97 results on '"Huanquan Zheng"'
Search Results
2. ROOT HAIR DEFECTIVE3 Is a Receptor for Selective Autophagy of the Endoplasmic Reticulum in Arabidopsis
- Author
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Jiaqi Sun, Weina Wang, and Huanquan Zheng
- Subjects
ER ,ER stress ,ER-phagy ,RHD3 ,Atg8 ,autophagosomes ,Plant culture ,SB1-1110 - Abstract
ROOT HAIR DEFECTIVE3 (RHD3) is a plant member of atlastin GTPases, which belong to an evolutionally conserved family of proteins that mediate the homotypic fusion of the endoplasmic reticulum (ER). An atlastin in mammalian cells has recently been shown to act as an ER-phagy receptor for selective autophagy of the ER (ER-phagy) during nutrient starvation. Although RHD3 has been indicated to play a role in ER stress response, it is not very clear how RHD3 is involved in the process. In this study, we showed that the rhd3 mutant is hyposensitive to ER as well as salt stress. We employed an YFP-tagged ER membrane marker YFP-TMC to monitor the efficiency of ER-phagy microscopically and biochemically. We found that rhd3 is defective in ER-phagy under ER stress. Furthermore, there is an increased association of YFP-RHD3 with ATG8e-marked autophagosomes. YFP-RHD3 is also visible with ATG8e in the vacuole, and there is a breakdown of YFP-RHD3 under ER stress. RHD3 has two putative ATG8 interaction motifs (AIM1-2). We revealed that RHD3 but not RHD3(ΔAIM1) physically interacts with ATG8, a core autophagosomal component that interacts with various receptor proteins to recruit cargos for degradation by selective autophagy. Furthermore, their interaction is enhanced under ER stress. We thus propose that RHD3 acts as an ER-phagy receptor under ER stress to promote ER-phagy in Arabidopsis.
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- 2022
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3. Osj10gBTF3-Mediated Import of Chloroplast Protein Is Essential for Pollen Development in Rice
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Xue-jiao Liu, Jiaqi Sun, Yuqing Huang, Chao Li, Peng Zheng, Yue Yuan, Hao Chen, Mehmood Jan, Huanquan Zheng, Hao Du, and Jumin Tu
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NAC protein ,chloroplast import ,pollen development ,OsHSP82 ,rice ,Plant culture ,SB1-1110 - Abstract
Chloroplasts are crucial organelles for the generation of fatty acids and starch required for plant development. Nascent polypeptide-associated complex (NAC) proteins have been implicated in development as transcription factors. However, their chaperone roles in chloroplasts and their relationship with pollen development in plants remain to be elucidated. Here, we demonstrated that Osj10gBTF3, a NAC protein, regulates pollen and chloroplast development in rice by coordinating with a Hsp90 family chaperone OsHSP82 to mediate chloroplast import. Knockout of Osj10gBTF3 affects pollen and chloroplast development and significantly reduces the accumulation of fertility-related chloroplast protein OsPPR676. Both Osj10gBTF3 and OsHSP82 interact with OsPPR676. Interestingly, the interaction between OsHSP82 and OsPPR676 is only found in the cytoplasm, while the interaction between Osj10gBTF3 and OsPPR676 also occurs inside the chloroplast. The chloroplast stroma chaperone OsCpn60 can also be co-precipitated with Osj10gBTF3, but not with OsHSP82. Further investigation indicates that Osj10gBTF3 enters the chloroplast stroma possibly through the inner chloroplast membrane channel protein Tic110 and then recruits OsCpn60 for the folding or assembly of OsPPR676. Our results reveal a chaperone role of Osj10gBTF3 in chloroplast import different from Hsp90 and provide a link between chloroplast transport and pollen development in rice.
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- 2021
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4. Characterization of the Populus Rab family genes and the function of PtRabE1b in salt tolerance
- Author
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Jin Zhang, Yu Li, Bobin Liu, Lijuan Wang, Li Zhang, Jianjun Hu, Jun Chen, Huanquan Zheng, and Mengzhu Lu
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Populus ,Rab GTPase ,Phylogenetic analysis ,Co-expression network ,Subcellular localization ,Salt tolerance ,Botany ,QK1-989 - Abstract
Abstract Background Rab proteins form the largest family of the Ras superfamily of small GTP-binding proteins and regulate intracellular trafficking pathways. However, the function of the Rab proteins in woody species is still an open question. Results Here, a total of 67 PtRabs were identified in Populus trichocarpa and categorized into eight subfamilies (RabA-RabH). Based on their chromosomal distribution and duplication blocks in the Populus genome, a total of 27 PtRab paralogous pairs were identified and all of them were generated by whole-genome duplication events. Combined the expression correlation and duplication date, the PtRab paralogous pairs that still keeping highly similar expression patterns were generated around the latest large-scale duplication (~ 13 MYA). The cis-elements and co-expression network of unique expanded PtRabs suggest their potential roles in poplar development and environmental responses. Subcellular localization of PtRabs from each subfamily indicates each subfamily shows a localization pattern similar to what is revealed in Arabidopsis but RabC shows a localization different from their counterparts. Furthermore, we characterized PtRabE1b by overexpressing its constitutively active mutant PtRabE1b(Q74L) in poplar and found that PtRabE1b(Q74L) enhanced the salt tolerance. Conclusions These findings provide new insights into the functional divergence of PtRabs and resources for genetic engineering resistant breeding in tree species.
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- 2018
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5. A Poplar Rust Effector Protein Associates with Protein Disulfide Isomerase and Enhances Plant Susceptibility
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Mst Hur Madina, Md Saifur Rahman, Xiaoqiang Huang, Yang Zhang, Huanquan Zheng, and Hugo Germain
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fungal rust ,effector ,GxxxG motif ,protein disulfide isomerase ,helper protein ,plant susceptibility ,Biology (General) ,QH301-705.5 - Abstract
Melampsora larici-populina (Mlp), the causal agent of Populus leaf rust, secretes an array of effectors into the host through the haustorium to gain nutrients and suppress immunity. The precise mechanisms by which these effectors promote virulence remain unclear. To address this question, we developed a transgenic Arabidopsis line expressing a candidate effector, Mlp124357. Constitutive expression of the effector increased plant susceptibility to pathogens. A GxxxG motif present in Mlp124357 is required for its subcellular localization at the vacuolar membrane of the plant cell, as replacement of the glycine residues with alanines led to the delocalization of Mlp124357 to the nucleus and cytoplasm. We used immunoprecipitation and mass spectrometry (MS) to identify Mlp124357 interaction partners. Only one of the putative interaction partners knock-out line caused delocalization of the effector, indicating that Arabidopsis protein disulfide isomerase-11 (AtPDI-11) is required for the effector localization. This interaction was further confirmed by a complementation test, a yeast-two hybrid assay and a molecular modeling experiment. Moreover, localization results and infection assays suggest that AtPDI-11 act as a helper for Mlp124357. In summary, our findings established that one of Mlp effectors resides at the vacuole surface and modulates plant susceptibility.
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- 2020
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6. Intracellular Localization and Movement Phenotypes of Alfalfa mosaic virus Movement Protein Mutants
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Mei Huang, Laurian Jongejan, Huanquan Zheng, Lee Zhang, and John F. Bol
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Microbiology ,QR1-502 ,Botany ,QK1-989 - Abstract
Thirteen mutations were introduced in the movement protein (MP) gene of Alfalfa mosaic virus (AMV) fused to the green fluorescent protein (GFP) gene and the mutant MP-GFP fusions were expressed transiently in tobacco protoplasts, tobacco suspension cells, and epidermal cells of tobacco leaves. In addition, the mutations were introduced in the MP gene of AMV RNA 3 and the mutant RNAs were used to infect tobacco plants. Ten mutants were affected in one or more of the following functions of MP: the formation of tubular structures on the surface of protoplasts, association with the endoplasmic reticulum (ER) of suspension cells and epidermal cells, targeting to punctate structures in the cell wall of epidermis cells, movement from transfected cells to adjacent cells in epidermis tissue, cell-to-cell movement, or long-distance movement in plants. The mutations point to functional domains of the MP and support the proposed order of events in AMV transport. Studies with several inhibitors indicate that actin or microtubule components of the cytoskeleton are not involved in tubule formation by AMV MP. Evidence was obtained that tubular structures on the surface of transfected protoplasts contain ER- or plasmalemma-derived material.
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- 2001
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7. Alfalfa Mosaic Virus Movement Protein Induces Tubules in Plant Protoplasts
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Huanquan Zheng, Guiling Wang, and Lee Zhang
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Microbiology ,QR1-502 ,Botany ,QK1-989 - Abstract
The alfalfa mosaic virus (AlMV) movement protein (MP) was fused with the green fluorescence protein (GFP). The MP-GFP fusion was transiently expressed in protoplasts prepared from Nicotiana tabacum, resulting in the production of long, extending, tubular structures protruding from the protoplast surface. Deletions of MP amino acids 1 to 77, 84 to 142, or 226 to 300 all affected tubule formation. Hence, the AlMV MP is solely required for the induction of the tubular structures, and the results suggest that AlMV may move from cell to cell via tubules.
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- 1997
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8. Contribution of host intracellular transport machineries to intercellular movement of turnip mosaic virus.
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Maxime Agbeci, Romain Grangeon, Richard S Nelson, Huanquan Zheng, and Jean-François Laliberté
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Immunologic diseases. Allergy ,RC581-607 ,Biology (General) ,QH301-705.5 - Abstract
The contribution of different host cell transport systems in the intercellular movement of turnip mosaic virus (TuMV) was investigated. To discriminate between primary infections and secondary infections associated with the virus intercellular movement, a gene cassette expressing GFP-HDEL was inserted adjacent to a TuMV infectious cassette expressing 6K₂:mCherry, both within the T-DNA borders of the binary vector pCambia. In this system, both gene cassettes were delivered to the same cell by a single binary vector and primary infection foci emitted green and red fluorescence while secondarily infected cells emitted only red fluorescence. Intercellular movement was measured at 72 hours post infiltration and was estimated to proceed at an average rate of one cell being infected every three hours over an observation period of 17 hours. To determine if the secretory pathway were important for TuMV intercellular movement, chemical and protein inhibitors that blocked both early and late secretory pathways were used. Treatment with Brefeldin A or Concanamycin A or expression of ARF1 or RAB-E1d dominant negative mutants, all of which inhibit pre- or post-Golgi transport, reduced intercellular movement by the virus. These treatments, however, did not inhibit virus replication in primary infected cells. Pharmacological interference assays using Tyrphostin A23 or Wortmannin showed that endocytosis was not important for TuMV intercellular movement. Lack of co-localization by endocytosed FM4-64 and Ara7 (AtRabF2b) with TuMV-induced 6K₂-tagged vesicles further supported this conclusion. Microfilament depolymerizing drugs and silencing expression of myosin XI-2 gene, but not myosin VIII genes, also inhibited TuMV intercellular movement. Expression of dominant negative myosin mutants confirmed the role played by myosin XI-2 as well as by myosin XI-K in TuMV intercellular movement. Using this dual gene cassette expression system and transport inhibitors, components of the secretory and actomyosin machinery were shown to be important for TuMV intercellular spread.
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- 2013
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9. LUNAPARK Is an E3 Ligase That Mediates Degradation of ROOT HAIR DEFECTIVE3 to Maintain a Tubular ER Network in Arabidopsis
- Author
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Huanquan Zheng, Jiaqi Sun, and Nooshin Movahed
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0106 biological sciences ,0301 basic medicine ,Atlastin ,biology ,Endoplasmic reticulum ,Cell Biology ,Plant Science ,GTPase ,Root hair ,biology.organism_classification ,01 natural sciences ,Ubiquitin ligase ,Cell biology ,03 medical and health sciences ,030104 developmental biology ,Ubiquitin ,Arabidopsis ,biology.protein ,Arabidopsis thaliana ,010606 plant biology & botany - Abstract
ROOT HAIR DEFECTIVE3 (RHD3) is an atlastin GTPase involved in homotypic fusion of endoplasmic reticulum (ER) tubules in the formation of the interconnected ER network. Because excessive fusion of ER tubules will lead to the formation of sheet-like ER, the action of atlastin GTPases must be tightly regulated. We show here that RHD3 physically interacts with two Arabidopsis (Arabidopsis thaliana) LUNAPARK proteins, LNP1 and LNP2, at three-way junctions of the ER, the sites where different ER tubules fuse. Recruited by RHD3 to newly formed three-way junctions, LNPs act negatively with RHD3 to stabilize the nascent three-way junctions of the ER. Without this LNP-mediated stabilization, in Arabidopsis lnp1-1 lnp2-1 mutant cells, the ER becomes a dense tubular network. Interestingly, in lnp1-1 lnp2-1 mutant cells, the expression level of RHD3 is higher than that in wild-type plants. RHD3 is degraded more slowly in the absence of LNPs as well as in the presence of MG132 and concanamycin A. However, in the presence of LNPs, the degradation of RHD3 is promoted. We have provided in vitro evidence that Arabidopsis LNPs have E3 ubiquitin ligase activity and that LNP1 can directly ubiquitinate RHD3. Our data show that after ER fusion is completed, RHD3 is degraded by LNPs so that nascent three-way junctions can be stabilized and a tubular ER network can be maintained.
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- 2020
10. An essential role for Arabidopsis Trs33 in cell growth and organization in plant apical meristems
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Jun Chen, Jianbo Li, Shutang Zhao, Lijuan Wang, Jin Zhang, Weina Wang, Bobin Liu, Xingyun Qi, Huanquan Zheng, and Mengzhu Lu
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0106 biological sciences ,0301 basic medicine ,Transcription, Genetic ,Meristem ,Arabidopsis ,Vesicular Transport Proteins ,Golgi Apparatus ,Plant Science ,GTPase ,Biology ,01 natural sciences ,03 medical and health sciences ,Gene Expression Regulation, Plant ,Auxin ,Plant Cells ,Cell Proliferation ,chemistry.chemical_classification ,Indoleacetic Acids ,Arabidopsis Proteins ,Membrane Transport Proteins ,General Medicine ,Plants, Genetically Modified ,Subcellular localization ,biology.organism_classification ,Cell biology ,Protein Transport ,Fertility ,030104 developmental biology ,chemistry ,PIN1 ,RNA Interference ,Rab ,Agronomy and Crop Science ,Functional divergence ,010606 plant biology & botany - Abstract
Trafficking protein particle (TRAPP) complexes subunit gene AtTrs33 plays an important role in keeping apical meristematic activity and dominance in Arabidopsis. TRAPP complexes, composed of multimeric subunits, are guanine-nucleotide exchange factors for certain Rab GTPases and are believed to be involved in the regulation of membrane trafficking, but the cases in Arabidopsis are largely unknown. Trs33, recently proposed to be a component of TRAPP IV, is non-essential in yeast cells. A single copy of Trs33 gene, AtTrs33, was identified in Arabidopsis. GUS activity assay indicated that AtTrs33 was ubiquitously expressed. Based on a T-DNA insertion line, we found that loss-of-function of AtTrs33 is lethal for apical growth. Knock-down or knock-in of AtTrs33 affects apical meristematic growth and fertility, which indicates that AtTrs33 plays an important role in keeping apical meristematic activity and dominance in Arabidopsis. Analysis of auxin responses and PIN1/2 localization indicate that impaired apical meristematic activity and dominance were caused by altered auxin responses through non-polarized PIN1 localization. The present study reported that AtTrs33 plays an essential role in Arabidopsis cell growth and organization, which is different with its homologue in yeast. These findings provide new insights into the functional divergence of TRAPP subunits.
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- 2019
11. ROOT HAIR DEFECTIVE3 Is a Receptor for Selective Autophagy of the Endoplasmic Reticulum in
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Jiaqi, Sun, Weina, Wang, and Huanquan, Zheng
- Abstract
ROOT HAIR DEFECTIVE3 (RHD3) is a plant member of atlastin GTPases, which belong to an evolutionally conserved family of proteins that mediate the homotypic fusion of the endoplasmic reticulum (ER). An atlastin in mammalian cells has recently been shown to act as an ER-phagy receptor for selective autophagy of the ER (ER-phagy) during nutrient starvation. Although RHD3 has been indicated to play a role in ER stress response, it is not very clear how RHD3 is involved in the process. In this study, we showed that the
- Published
- 2021
12. ECERIFERUM11/C-TERMINAL DOMAIN PHOSPHATASE-LIKE2 Affects Secretory Trafficking
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Gillian H. Dean, Lin Shi, George W. Haughn, Huanquan Zheng, Ljerka Kunst, Miranda J. Meents, and Tegan M. Haslam
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0106 biological sciences ,Physiology ,Ubiquitin-Protein Ligases ,Mutant ,Arabidopsis ,Plant Science ,01 natural sciences ,Plant Epidermis ,Cell wall ,Gene Expression Regulation, Plant ,Genetics ,Arabidopsis thaliana ,Secretion ,Research Articles ,Cell Nucleus ,biology ,Arabidopsis Proteins ,Chemistry ,C-terminus ,Plants, Genetically Modified ,beta-Galactosidase ,biology.organism_classification ,Plant cell ,Cell biology ,Protein Transport ,Phenotype ,Seeds ,Secondary cell wall ,010606 plant biology & botany - Abstract
Secretory trafficking is highly conserved in all eukaryotic cells and is required for secretion of proteins as well as extracellular matrix components. In plants, the export of cuticular waxes and various cell wall components relies on secretory trafficking, but the molecular mechanisms underlying their secretion are not well understood. In this study, we characterize the Arabidopsis (Arabidopsis thaliana) dwarf eceriferum11 (cer11) mutant and we show that it exhibits reduced stem cuticular wax deposition, aberrant seed coat mucilage extrusion, and delayed secondary cell wall columella formation, as well as a block in secretory GFP trafficking. Cloning of the CER11 gene revealed that it encodes a C-TERMINAL DOMAIN PHOSPHATASE-LIKE2 (CPL2) protein. Thus, secretory trafficking in plant cells in general, and secretion of extracellular matrix constituents in developing epidermal cells in particular, involves a dephosphorylation step catalyzed by CER11/CPL2.
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- 2019
13. Turnip Mosaic Virus Components Are Released into the Extracellular Space by Vesicles in Infected Leaves
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Daniel Garcia Cabanillas, Jean-François Laliberté, Juan Wan, Nooshin Movahed, Hojatollah Vali, Huanquan Zheng, McGill University = Université McGill [Montréal, Canada], Institut Armand Frappier (INRS-IAF), Institut National de la Recherche Scientifique [Québec] (INRS)-Réseau International des Instituts Pasteur (RIIP), Institut National de la Recherche Scientifique [Québec] (INRS), This research was supported by grants from the Natural Sciences and Engineering Research Council (NSERC) of Canada and from le Fonds de Recherche du Québec sur la Nature et les Technologies (FRQNT) to J.-F. L and H.Z., and We would like to thank the research group of the Facility for Electron Microscopy Research (FEMR) at McGill University, where we conducted all the experiments of transmission electron microscopy and Focused Ion Beam Systems and Dual Beam TM (FIB) microscopy. We thank Roger Innes (Indiana State University) for providing 35S::GFP -PEN1 and 35S::GmMANI49sYFP transgenic plants
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Proteomics ,0106 biological sciences ,Physiology ,Viral protein ,viruses ,Potyvirus ,Arabidopsis ,Nicotiana benthamiana ,Plant Science ,Endoplasmic Reticulum ,Virus Replication ,medicine.disease_cause ,01 natural sciences ,Viral Proteins ,03 medical and health sciences ,Microscopy, Electron, Transmission ,Tobacco ,Genetics ,Extracellular ,medicine ,Turnip mosaic virus ,Endomembrane system ,News and Views ,030304 developmental biology ,0303 health sciences ,biology ,Chemistry ,Vesicle ,Multivesicular Bodies ,food and beverages ,Immunogold labelling ,biology.organism_classification ,3. Good health ,Cell biology ,Plant Leaves ,[SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology ,Viral replication ,Host-Pathogen Interactions ,Microscopy, Electron, Scanning ,RNA, Viral ,Extracellular Space ,010606 plant biology & botany - Abstract
International audience; Turnip mosaic virus (TuMV) reorganizes the endomembrane system of the infected cell to generate endoplasmic reticulum-derived motile vesicles containing viral replication complexes. The membrane-associated viral protein 6K2 plays a key role in the formation of these vesicles. Using confocal microscopy, we observed that this viral protein, a marker for viral replication complexes, localized in the extracellular space of infected Nicotiana benthamiana leaves. Previously, we showed that viral RNA is associated with multi-vesicular bodies (MVBs). Here, using transmission electron microscopy, we observed the proliferation of MVBs during infection and their fusion with the plasma membrane that resulted in the release of their intraluminal vesicles in the extracellular space. Immunogold labeling with a monoclonal antibody that recognizes double-stranded RNA indicated that the released vesicles contained viral RNA. Focused ion beam-extreme high-resolution scanning electron microscopy was used to generate a 3D image that showed extracellular vesicles in the cell wall. The presence of TuMV proteins in the extracellular space was confirmed by proteomic analysis of purified extracellular vesicles from Nicotiana benthamiana and Arabidopsis thaliana. Host proteins involved in biotic defense and in inter-organelle vesicular exchange were also detected. The association of extracellular vesicles with viral proteins and RNA emphasizes the implication of the plant extracellular space in viral infection.
- Published
- 2019
14. A Poplar Rust Effector Protein Associates with Protein Disulfide Isomerase and Enhances Plant Susceptibility
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Huanquan Zheng, Mst Hur Madina, Xiaoqiang Huang, Hugo Germain, Yang Zhang, and Saifur Rahman
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0106 biological sciences ,0301 basic medicine ,Immunoprecipitation ,Vacuole ,Biology ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Article ,03 medical and health sciences ,helper protein ,plant susceptibility ,Haustorium ,Arabidopsis ,Protein disulfide-isomerase ,lcsh:QH301-705.5 ,General Immunology and Microbiology ,Effector ,GxxxG motif ,biology.organism_classification ,Subcellular localization ,protein disulfide isomerase ,Cell biology ,fungal rust ,030104 developmental biology ,effector ,lcsh:Biology (General) ,Cytoplasm ,General Agricultural and Biological Sciences ,010606 plant biology & botany - Abstract
Melampsora larici-populina (Mlp), the causal agent of Populus leaf rust, secretes an array of effectors into the host through the haustorium to gain nutrients and suppress immunity. The precise mechanisms by which these effectors promote virulence remain unclear. To address this question, we developed a transgenic Arabidopsis line expressing a candidate effector, Mlp124357. Constitutive expression of the effector increased plant susceptibility to pathogens. A GxxxG motif present in Mlp124357 is required for its subcellular localization at the vacuolar membrane of the plant cell, as replacement of the glycine residues with alanines led to the delocalization of Mlp124357 to the nucleus and cytoplasm. We used immunoprecipitation and mass spectrometry (MS) to identify Mlp124357 interaction partners. Only one of the putative interaction partners knock-out line caused delocalization of the effector, indicating that Arabidopsis protein disulfide isomerase-11 (AtPDI-11) is required for the effector localization. This interaction was further confirmed by a complementation test, a yeast-two hybrid assay and a molecular modeling experiment. Moreover, localization results and infection assays suggest that AtPDI-11 act as a helper for Mlp124357. In summary, our findings established that one of Mlp effectors resides at the vacuole surface and modulates plant susceptibility.
- Published
- 2020
15. New insight into bulb dynamics in the vacuolar lumen ofArabidopsiscells
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Mst Hur Madina, Huanquan Zheng, and Hugo Germain
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0106 biological sciences ,0301 basic medicine ,Ecology ,Vacuolar lumen ,Fluorescence recovery after photobleaching ,Plant Science ,Vacuole ,Biology ,biology.organism_classification ,01 natural sciences ,Fusion protein ,Green fluorescent protein ,Bulb ,03 medical and health sciences ,030104 developmental biology ,nervous system ,Arabidopsis ,Organelle ,Botany ,Biophysics ,Ecology, Evolution, Behavior and Systematics ,010606 plant biology & botany - Abstract
Plant vacuoles are multifunctional organelles with dynamic and transient membranous structures, such as trans-vacuolar strands and bulbs. Bulbs are highly mobile structures that travel along trans-vacuolar strands. A candidate effector protein from Melampsora larici-populina (Mlp124357) fused with the enhanced green fluorescent protein (eGFP) was used to investigate the properties of central vacuoles and their bulbs. We discovered the coexistence of two bulb populations in Arabidopsis cells. In addition to previously-described bulbs, which present even marker protein distribution on the bulb surface, we discerned bulbs displaying irregular fusion protein distribution. Using fluorescence recovery after photobleaching (FRAP), we also demonstrated that bulbs do not exchange proteins with the tonoplast once they are formed. These results show that more than one type of bulb may co-exist in the same cell and provide evidence of micro-domains on the bulb surface. They also reveal that proteins do not flow freely from the tonoplast to the bulb membrane, giving new insight into the biology of tonoplast-derived substructures.
- Published
- 2018
16. Partnership in action: The endoplasmic reticulum regulates the cytoskeleton
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Huanquan Zheng
- Subjects
0106 biological sciences ,0303 health sciences ,Microtubule dynamics ,Physiology ,Chemistry ,Endoplasmic reticulum ,macromolecular substances ,Plant Science ,Endoplasmic Reticulum ,Plant cell ,Microtubules ,01 natural sciences ,Actins ,Cell biology ,03 medical and health sciences ,Microtubule ,Plant Cells ,Cytoskeleton ,Agronomy and Crop Science ,Actin ,030304 developmental biology ,010606 plant biology & botany - Abstract
The endoplasmic reticulum (ER) and the cytoskeleton are functionally linked in living cells. Past research has focused on how the cytoskeleton regulates ER dynamics. How the ER may contribute to cytoskeletal dynamics has been overlooked. In this commentary, I examined how the ER mediates actin and microtubule dynamics in plant cells.
- Published
- 2021
17. Efficient ER Fusion Requires a Dimerization and a C-Terminal Tail Mediated Membrane Anchoring of RHD3
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Huanquan Zheng and Jiaqi Sun
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0301 basic medicine ,Atlastin ,biology ,Physiology ,Endoplasmic reticulum ,Lipid bilayer fusion ,Plant Science ,GTPase ,biology.organism_classification ,Transmembrane protein ,Cell biology ,03 medical and health sciences ,Crystallography ,Cytosol ,030104 developmental biology ,Membrane ,Arabidopsis ,Genetics - Abstract
The endoplasmic reticulum (ER) is a network of tubules and sheets stretching throughout the eukaryotic cells. The formation of the ER requires homotypic membrane fusion, which is mediated by a family of Dynamin-like Atlastin GTPase proteins. The Arabidopsis (Arabidopsis thaliana) member ROOT HAIR DEFECTIVE3 (RHD3) has been demonstrated to mediate ER membrane fusion, but how exactly RHD3 is involved in the process is still unknown. Here we conducted systemic structure-function analyses of roles of different RHD3 domains in mediating ER fusion. We showed that efficient ER membrane fusion mediated by RHD3 requires a proper dimerization of RHD3 through the GTPase domain (GD) and the first and second three helix bundles (3HBs) in the middle domain. RHD3 has a 3HB-enriched middle domain longer than that of Atlastins, and we revealed that the third and fourth 3HBs are required for the stability of RHD3. The transmembrane segments of RHD3 are essential for targeting and retention of RHD3 in the ER and can also facilitate an oligomerization of RHD3. Furthermore, we showed that an amphipathic helix in the C-terminal cytosolic tail of RHD3 has a membrane anchoring ability that is required for efficient ER membrane fusion mediated by RHD3. This work contributes to a better understanding of a coordinated action of RHD3 in the fusion of ER membranes.
- Published
- 2017
18. Vacuolar membrane structures and their roles in plant-pathogen interactions
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Saifur Rahman, Huanquan Zheng, Hugo Germain, and Mst Hur Madina
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0106 biological sciences ,0301 basic medicine ,Hypersensitive response ,Plant Immunity ,Plant Science ,Vacuole ,Biology ,01 natural sciences ,03 medical and health sciences ,Immune system ,Organelle ,Genetics ,Plant defense against herbivory ,Pathogen ,Plant Proteins ,Cell Death ,food and beverages ,General Medicine ,Intracellular Membranes ,Plants ,Plant cell ,Cell biology ,030104 developmental biology ,Host-Pathogen Interactions ,Vacuoles ,Agronomy and Crop Science ,Biomarkers ,010606 plant biology & botany - Abstract
Short review focussing on the role and targeting of vacuolar substructure in plant immunity and pathogenesis. Plants lack specialized immune cells, therefore each plant cell must defend itself against invading pathogens. A typical plant defense strategy is the hypersensitive response that results in host cell death at the site of infection, a process largely regulated by the vacuole. In plant cells, the vacuole is a vital organelle that plays a central role in numerous fundamental processes, such as development, reproduction, and cellular responses to biotic and abiotic stimuli. It shows divergent membranous structures that are continuously transforming. Recent technical advances in visualization and live-cell imaging have significantly altered our view of the vacuolar structures and their dynamics. Understanding the active nature of the vacuolar structures and the mechanisms of vacuole-mediated defense responses is of great importance in understanding plant-pathogen interactions. In this review, we present an overview of the current knowledge about the vacuole and its internal structures, as well as their role in plant–microbe interactions. There is so far limited information on the modulation of the vacuolar structures by pathogens, but recent research has identified the vacuole as a possible target of microbial interference.
- Published
- 2019
19. Interactions between Transport Protein Particle (TRAPP) complexes and Rab GTPases in Arabidopsis
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Alexander Steiner, Ian Moore, Benjamin Al, Liam Elliott, Christina Ludwig, Pascal Falter-Braun, Bernhard Kuster, Raksha Ravikumar, Melina Altmann, Farhah F. Assaad, Christian Wiese, Chen Meng, Monika Kalde, Xingyun Qi, Susan Klaeger, Miriam Abele, Katarzyna Rybak, Huanquan Zheng, and Nils Kalbfuß
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0106 biological sciences ,0301 basic medicine ,Proteomics ,Proteome ,Arabidopsis ,Vesicular Transport Proteins ,Plant Science ,GTPase ,medicine.disease_cause ,01 natural sciences ,Models, Biological ,Exocytosis ,03 medical and health sciences ,Protein targeting ,Genetics ,medicine ,Arabidopsis thaliana ,Guanine Nucleotide Exchange Factors ,Cytokinesis ,Secretory Pathway ,biology ,Arabidopsis Thaliana ,Rab Gtpases ,Tethering Complexes ,Arabidopsis Proteins ,fungi ,Cell Biology ,biology.organism_classification ,Cell biology ,Protein Transport ,030104 developmental biology ,rab GTP-Binding Proteins ,Mutation ,Rab ,Guanine nucleotide exchange factor ,010606 plant biology & botany - Abstract
Transport Protein Particle II (TRAPPII) is essential for exocytosis, endocytosis, protein sorting and cytokinesis. In spite of a considerable understanding of its biological role, little information is known about Arabidopsis TRAPPII complex topology and molecular function. In this study, independent proteomic approaches initiated with TRAPP components or Rab-A GTPase variants converge on the TRAPPII complex. We show that the Arabidopsis genome encodes the full complement of 13 TRAPPC subunits, including four previously unidentified components. A dimerization model is proposed to account for binary interactions between TRAPPII subunits. Preferential binding to dominant negative (GDP-bound) versus wild-type or constitutively active (GTP-bound) RAB-A2a variants discriminates between TRAPPII and TRAPPIII subunits and shows that Arabidopsis complexes differ from yeast but resemble metazoan TRAPP complexes. Analyzes of Rab-A mutant variants in trappii backgrounds provide genetic evidence that TRAPPII functions upstream of RAB-A2a, allowing us to propose that TRAPPII is likely to behave as a guanine nucleotide exchange factor (GEF) for the RAB-A2a GTPase. GEFs catalyze exchange of GDP for GTP; the GTP-bound, activated, Rab then recruits a diverse local network of Rab effectors to specify membrane identity in subsequent vesicle fusion events. Understanding GEF-Rab interactions will be crucial to unravel the co-ordination of plant membrane traffic.
- Published
- 2019
20. A Host ER Fusogen Is Recruited by Turnip Mosaic Virus for Maturation of Viral Replication Vesicles
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Jiaqi Sun, Jean-François Laliberté, Nooshin Movahed, Hojatollah Vali, Huanquan Zheng, Department of Biology [Montréal], McGill University = Université McGill [Montréal, Canada], Facility for Electron Microscopy Research [Montréal] (FEMR), Institut Armand Frappier (INRS-IAF), Institut National de la Recherche Scientifique [Québec] (INRS)-Réseau International des Instituts Pasteur (RIIP), and This work was supported by grants from the Natural Sciences and Engineering Research Council (NSERC) of Canada and from the Quebec Fund for Research in Nature and Technology (to J.-F.L. and H.Z)
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0106 biological sciences ,Mutation ,Physiology ,Viral protein ,Host (biology) ,Vesicle ,Endoplasmic reticulum ,viruses ,RNA ,Plant Science ,Biology ,medicine.disease_cause ,biology.organism_classification ,01 natural sciences ,Cell biology ,Viral replication ,[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology ,Genetics ,medicine ,Turnip mosaic virus ,010606 plant biology & botany - Abstract
International audience; Like other positive-strand RNA viruses, the Turnip mosaic virus (TuMV) infection leads to the formation of viral vesicles at the endoplasmic reticulum (ER). Once released from the ER, the viral vesicles mature intracellularly and then move intercellularly. While it is known that the membrane-associated viral protein 6K2 plays a role in the process, the contribution of host proteins has been poorly defined. In this article, we show that 6K2 interacts with RHD3, an ER fusogen required for efficient ER fusion. When RHD3 is mutated, a delay in the development of TuMV infection is observed. We found that the replication of TuMV and the cell-to-cell movement of its replication vesicles are impaired in rhd3 This defect can be tracked to a delayed maturation of the viral vesicles from the replication incompetent to the competent state. Furthermore, 6K2 can relocate RHD3 from the ER to viral vesicles. However, a Golgi-localized mutated 6K2GV is unable to interact and relocate RHD3 to viral vesicles. We conclude that the maturation of TuMV replication vesicles requires RHD3 for efficient viral replication and movement.
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- 2019
21. Turnip Mosaic Virus Uses the SNARE Protein VTI11 in an Unconventional Route for Replication Vesicle Trafficking
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Hugo Germain, Daniel Garcia Cabanillas, Huanquan Zheng, Yasuyuki Yamaji, Nooshin Movahed, Jean-François Laliberté, Jun Jiang, Institut Armand Frappier (INRS-IAF), Institut National de la Recherche Scientifique [Québec] (INRS)-Réseau International des Instituts Pasteur (RIIP), McGill University = Université McGill [Montréal, Canada], Université du Québec à Trois-Rivières (UQTR), The University of Tokyo (UTokyo), This work was supported by grants from the Natural Science and Engineering Research Council of Canada and from Le Fonds Québécois de Recherche sur la Nature et les Technologies to H.Z. and J.-F.L., and We thank F. Prieto Bruckner and V. Schurdi-Levraud for their advice and technical support for RT-qPCR experiments. We thank J. Tremblay for his technical expertise assistance with confocal microscopy and S.G. Lazarowitz (Cornell University) for the Arabidopsis syta-1 seeds. We thank P. Moffett (Université de Sherbrooke) for valuable advice and for critically reading the manuscript.
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0301 basic medicine ,Viral protein ,viruses ,[SDV]Life Sciences [q-bio] ,Amino Acid Motifs ,Potyvirus ,Arabidopsis ,Vesicular Transport Proteins ,Golgi Apparatus ,Plant Science ,Endoplasmic Reticulum ,Virus Replication ,medicine.disease_cause ,Virus ,Synaptotagmins ,Viral Proteins ,03 medical and health sciences ,symbols.namesake ,Tobacco ,medicine ,Turnip mosaic virus ,Research Articles ,Brefeldin A ,biology ,Arabidopsis Proteins ,Endoplasmic reticulum ,Cell Biology ,Qb-SNARE Proteins ,Golgi apparatus ,Viral membrane ,Plants, Genetically Modified ,biology.organism_classification ,3. Good health ,Cell biology ,Plant Leaves ,030104 developmental biology ,Viral replication ,Viral replication complex ,Host-Pathogen Interactions ,Mutagenesis, Site-Directed ,symbols ,SNARE Proteins - Abstract
International audience; Infection of plant cells by RNA viruses leads to the generation of organelle-like subcellular structures that contain the viral replication complex. During Turnip mosaic virus (TuMV) infection of Nicotiana benthamiana, the viral membrane protein 6K2 plays a key role in the release of motile replication vesicles from the host endoplasmic reticulum (ER). Here, we demonstrate that 6K2 contains a GxxxG motif within its predicted transmembrane domain that is vital for TuMV infection. Replacement of the Gly with Val within this motif inhibited virus production, and this was due to a relocation of the viral protein to the Golgi apparatus and the plasma membrane. This indicated that passage of 6K2 through the Golgi apparatus is a dead-end avenue for virus infection. Impairing the fusion of transport vesicles between the ER and the Golgi apparatus by overexpression of the SNARE Sec22 protein resulted in enhanced intercellular virus movement. Likewise, expression of nonfunctional, Golgi-located synaptotagmin during infection enhanced TuMV intercellular movement. 6K2 copurified with VTI11, a prevacuolar compartment SNARE protein. An Arabidopsis thaliana vti11 mutant was completely resistant to TuMV infection. We conclude that TuMV replication vesicles bypass the Golgi apparatus and take an unconventional pathway that may involve prevacuolar compartments/multivesicular bodies for virus infection.
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- 2018
22. A GTPase-Dependent Fine ER Is Required for Localized Secretion in Polarized Growth of Root Hairs
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Jiaqi Sun, Xingyun Qi, and Huanquan Zheng
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0301 basic medicine ,Atlastin ,Physiology ,Endoplasmic reticulum ,Plant Science ,Root hair ,Biology ,Cell biology ,03 medical and health sciences ,030104 developmental biology ,Live cell imaging ,Cytoplasm ,Microtubule ,Botany ,Cell polarity ,Genetics ,Secretion - Abstract
The endoplasmic reticulum (ER) is a cellular network comprising membrane tubules and sheets stretching throughout the cytoplasm. Atlastin GTPases, including Atlastin-1 in mammals and RHD3 in plants, play a role in the generation of the interconnected tubular ER network by promoting the fusion of ER tubules. Root hairs in rhd3 are short and wavy, a defect reminiscent of axon growth in cells with depleted Atlastin-1. However, how a loss in the ER complexity could lead to a defective polarized cell growth of root hairs or neurons remains elusive. Using live-cell imaging techniques, we reveal that, a fine ER distribution, which is found in the subapical zone of growing root hairs of wild-type plants, is altered to thick bundles in rhd3. The localized secretion to the apical dome as well as the apical localization of root hair growth regulator ROP2 is oscillated in rhd3. Interestingly, the shift of ROP2 precedes the shift of localized secretion as well as the fine ER distribution in rhd3. Our live imaging and pharmacologic modification of root hair growth defects in rhd3 suggest that there is interplay between the ER and microtubules in the polarized cell growth of root hairs. We hypothesize that, under the guidance of ROP2, RHD3, together with the action of microtubules, is required for the formation of a fine ER structure in the subapical zone of growing root hairs. This fine ER structure is essential for the localized secretion to the apical dome in polarized cell growth.
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- 2016
23. Characterization of the Populus Rab family genes and the function of PtRabE1b in salt tolerance
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Jun Chen, Jin Zhang, Yu Li, Li Zhang, Bobin Liu, Lijuan Wang, Huanquan Zheng, Jianjun Hu, and Mengzhu Lu
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0301 basic medicine ,Populus trichocarpa ,Subfamily ,Plant Science ,Genes, Plant ,Chromosomes, Plant ,03 medical and health sciences ,lcsh:Botany ,Arabidopsis ,Gene duplication ,Promoter Regions, Genetic ,Gene ,Conserved Sequence ,Phylogeny ,Plant Proteins ,Genetics ,Co-expression network ,Phylogenetic analysis ,biology ,Subcellular localization ,fungi ,Salt-Tolerant Plants ,Salt Tolerance ,biology.organism_classification ,lcsh:QK1-989 ,Populus ,030104 developmental biology ,rab GTP-Binding Proteins ,Rab ,Ras superfamily ,Transcriptome ,Rab GTPase ,Functional divergence ,Research Article - Abstract
Background Rab proteins form the largest family of the Ras superfamily of small GTP-binding proteins and regulate intracellular trafficking pathways. However, the function of the Rab proteins in woody species is still an open question. Results Here, a total of 67 PtRabs were identified in Populus trichocarpa and categorized into eight subfamilies (RabA-RabH). Based on their chromosomal distribution and duplication blocks in the Populus genome, a total of 27 PtRab paralogous pairs were identified and all of them were generated by whole-genome duplication events. Combined the expression correlation and duplication date, the PtRab paralogous pairs that still keeping highly similar expression patterns were generated around the latest large-scale duplication (~ 13 MYA). The cis-elements and co-expression network of unique expanded PtRabs suggest their potential roles in poplar development and environmental responses. Subcellular localization of PtRabs from each subfamily indicates each subfamily shows a localization pattern similar to what is revealed in Arabidopsis but RabC shows a localization different from their counterparts. Furthermore, we characterized PtRabE1b by overexpressing its constitutively active mutant PtRabE1b(Q74L) in poplar and found that PtRabE1b(Q74L) enhanced the salt tolerance. Conclusions These findings provide new insights into the functional divergence of PtRabs and resources for genetic engineering resistant breeding in tree species. Electronic supplementary material The online version of this article (10.1186/s12870-018-1342-1) contains supplementary material, which is available to authorized users.
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- 2018
24. AtBET5 is essential for exine pattern formation and apical meristem organization in Arabidopsis
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Jianbo Li, Shutang Zhao, Jun Chen, Lijuan Wang, Xingyun Qi, Huanquan Zheng, Mengzhu Lu, Jin Zhang, Bobin Liu, and Hongying Li
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0106 biological sciences ,0301 basic medicine ,Endosome ,Recombinant Fusion Proteins ,Meristem ,Arabidopsis ,Vesicular Transport Proteins ,Plant Science ,01 natural sciences ,03 medical and health sciences ,symbols.namesake ,Biopolymers ,Sporopollenin ,Plant Growth Regulators ,Auxin ,RNA interference ,Genes, Reporter ,Genetics ,Guanine Nucleotide Exchange Factors ,Gene ,chemistry.chemical_classification ,biology ,Indoleacetic Acids ,Arabidopsis Proteins ,Membrane Transport Proteins ,General Medicine ,Golgi apparatus ,biology.organism_classification ,Carotenoids ,Cell biology ,Mutagenesis, Insertional ,030104 developmental biology ,chemistry ,symbols ,Pollen ,RNA Interference ,Agronomy and Crop Science ,010606 plant biology & botany - Abstract
BET5 is a component of trafficking protein particle (TRAPP) which has been studied extensively in non-plant organisms where they are involved in membrane trafficking within Golgi and between Golgi and early endosomes. Recent analysis of TRAPP in different classes of organisms indicates that TRAPP function might exhibit differences among organisms. A single copy of the BET5 gene named AtBET5 was found in the Arabidopsis genome based on sequence similarity. Developmental phenotype and the underlying mechanisms have been characterized upon transcriptional knock-down lines generated by both T-DNA insertion and RNAi. Pollen grains of the T-DNA insertional line present reduced fertility and pilate exine instead of tectate exine. Perturbation of the AtBET5 expression by RNAi leads to apical meristematic organization defects and reduced fertility as well. The reduced fertility was due to the pollination barrier caused by an altered composition and structure of pollen walls. Auxin response in root tip cells is altered and there is a severe disruption in polar localization of PIN1-GFP, but to a less extent of PIN2-GFP in the root tips, which causes the apical meristematic organization defects and might also be responsible for the secretion of sporopollenin precursor or polar targeting of sporopollenin precursor transporters.
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- 2018
25. Additional file 15: of Characterization of the Populus Rab family genes and the function of PtRabE1b in salt tolerance
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Zhang, Jin, Li, Yu, Bobin Liu, Lijuan Wang, Zhang, Li, Jianjun Hu, Chen, Jun, Huanquan Zheng, and Mengzhu Lu
- Abstract
Table S6 qRT-PCR Primers used in this study. (DOCX 18 kb)
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- 2018
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26. Additional file 7: of Characterization of the Populus Rab family genes and the function of PtRabE1b in salt tolerance
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Zhang, Jin, Li, Yu, Bobin Liu, Lijuan Wang, Zhang, Li, Jianjun Hu, Chen, Jun, Huanquan Zheng, and Mengzhu Lu
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Table S2. Probe sets corresponding to PtRab genes. (DOCX 22 kb)
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- 2018
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27. Cylindrical Inclusion Protein of Turnip Mosaic Virus Serves as a Docking Point for the Intercellular Movement of Viral Replication Vesicles
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Jiaqi Sun, Jean-François Laliberté, Huanquan Zheng, Hojatollah Vali, Camilo Patarroyo, and Nooshin Movahed
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0301 basic medicine ,Gene Expression Regulation, Viral ,Physiology ,Viral protein ,viruses ,Potyvirus ,Plant Science ,Plasmodesma ,medicine.disease_cause ,Virus Replication ,Inclusion bodies ,03 medical and health sciences ,Viral Proteins ,Plant virus ,Tobacco ,Genetics ,medicine ,Turnip mosaic virus ,biology ,Potyviridae ,Vesicle ,food and beverages ,Articles ,biology.organism_classification ,Virology ,Cell biology ,Plant Viral Movement Proteins ,030104 developmental biology ,Viral replication - Abstract
Plant viruses move from the initially infected cell to adjacent cells through plasmodesmata (PDs). To do so, viruses encode dedicated protein(s) that facilitate this process. How viral proteins act together to support the intercellular movement of viruses is poorly defined. Here, by using an infection-free intercellular vesicle movement assay, we investigate the action of CI (cylindrical inclusion) and P3N-PIPO (amino-terminal half of P3 fused to Pretty Interesting Potyviridae open reading frame), the two PD-localized potyviral proteins encoded by Turnip mosaic virus (TuMV), in the intercellular movement of the viral replication vesicles. We provide evidence that CI and P3N-PIPO are sufficient to support the PD targeting and intercellular movement of TuMV replication vesicles induced by 6K2, a viral protein responsible for the generation of replication vesicles. 6K2 interacts with CI but not P3N-PIPO. When this interaction is impaired, the intercellular movement of TuMV replication vesicles is inhibited. Furthermore, in transmission electron microscopy, vesicular structures are observed in connection with the cylindrical inclusion bodies at structurally modified PDs in cells coexpressing 6K2, CI, and P3N-PIPO. CI is directed to PDs through its interaction with P3N-PIPO. We hypothesize that CI serves as a docking point for PD targeting and the intercellular movement of TuMV replication vesicles. This work contributes to a better understanding of the roles of different viral proteins in coordinating the intercellular movement of viral replication vesicles.
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- 2017
28. Ultrastructural Characterization of Turnip Mosaic Virus-Induced Cellular Rearrangements Reveals Membrane-Bound Viral Particles Accumulating in Vacuoles
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Hojatollah Vali, Jeannie Mui, Jean-François Laliberté, Juan Wan, Kaustuv Basu, Huanquan Zheng, Institut Armand Frappier (INRS-IAF), Réseau International des Instituts Pasteur (RIIP)-Institut National de la Recherche Scientifique [Québec] (INRS), Facility for Electron Microscopy Research [Montréal] (FEMR), McGill University = Université McGill [Montréal, Canada], Department of Anatomy & Cell Biology, Department of Biology [Montréal], and This research was supported by grants from the Natural Sciences and Engineering Research Council (NSERC) of Canada and from le Fonds de Recherche du Québec sur la Nature et les Technologies (FRQNT) to H.Z. and J.-F.L.
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biology ,Endoplasmic reticulum ,[SDV]Life Sciences [q-bio] ,Immunology ,RNA ,Intracellular Membranes ,Immunogold labelling ,Viral membrane ,Endoplasmic Reticulum ,biology.organism_classification ,Microbiology ,Virus-Cell Interactions ,Cell biology ,Freeze substitution ,Viral replication ,Virology ,Insect Science ,Tobacco ,Vacuoles ,Turnip mosaic virus ,Endomembrane system ,Tymovirus - Abstract
Positive-strand RNA [(+) RNA] viruses remodel cellular membranes to facilitate virus replication and assembly. In the case of turnip mosaic virus (TuMV), the viral membrane protein 6K 2 plays an essential role in endomembrane alterations. Although 6K 2 -induced membrane dynamics have been widely studied by confocal microscopy, the ultrastructure of this remodeling has not been extensively examined. In this study, we investigated the formation of TuMV-induced membrane changes by chemical fixation and high-pressure freezing/freeze substitution (HPF/FS) for transmission electron microscopy at different times of infection. We observed the formation of convoluted membranes connected to rough endoplasmic reticulum (rER) early in the infection process, followed by the production of single-membrane vesicle-like (SMVL) structures at the midstage of infection. Both SMVL and double-membrane vesicle-like structures with electron-dense cores, as well as electron-dense bodies, were found late in the infection process. Immunogold labeling results showed that the vesicle-like structures were 6K 2 tagged and suggested that only the SMVL structures were viral RNA replication sites. Electron tomography (ET) was used to regenerate a three-dimensional model of these vesicle-like structures, which showed that they were, in fact, tubules. Late in infection, we observed filamentous particle bundles associated with electron-dense bodies, which suggests that these are sites for viral particle assembly. In addition, TuMV particles were observed to accumulate in the central vacuole as membrane-associated linear arrays. Our work thus unravels the sequential appearance of distinct TuMV-induced membrane structures for viral RNA replication, viral particle assembly, and accumulation. IMPORTANCE Positive-strand RNA viruses remodel cellular membranes for different stages of the infection process, such as protein translation and processing, viral RNA synthesis, particle assembly, and virus transmission. The ultrastructure of turnip mosaic virus (TuMV)-induced membrane remodeling was investigated over several days of infection. The first change that was observed involved endoplasmic reticulum-connected convoluted membrane accumulation. This was followed by the formation of single-membrane tubules, which were shown to be viral RNA replication sites. Later in the infection process, double-membrane tubular structures were observed and were associated with viral particle bundles. In addition, TuMV particles were observed to accumulate in the central vacuole as membrane-associated linear arrays. This work thus unravels the sequential appearance of distinct TuMV-induced membrane structures for viral RNA replication, viral particle assembly, and accumulation.
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- 2015
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29. The Vesicle-Forming 6K 2 Protein of Turnip Mosaic Virus Interacts with the COPII Coatomer Sec24a for Viral Systemic Infection
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Jean-François Laliberté, Jun Jiang, Daniel Garcia Cabanillas, Camilo Patarroyo, Huanquan Zheng, Institut Armand Frappier (INRS-IAF), Réseau International des Instituts Pasteur (RIIP)-Institut National de la Recherche Scientifique [Québec] (INRS), McGill University = Université McGill [Montréal, Canada], and This work was supported by grants from the Natural Science and Engineering Research Council (NSERC) of Canada and from Le Fonds Québécois de Recherche sur la Nature et les Technologies (FQRNT) to H.Z. and J.F.L.
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MESH: Vesicular Transport Proteins ,Viral protein ,[SDV]Life Sciences [q-bio] ,viruses ,DNA Mutational Analysis ,Potyvirus ,Immunology ,Arabidopsis ,Vesicular Transport Proteins ,MESH: Arabidopsis Proteins ,Biology ,MESH: Two-Hybrid System Techniques ,medicine.disease_cause ,Microbiology ,Virus ,Viral Proteins ,MESH: Potyvirus ,Viral entry ,Two-Hybrid System Techniques ,Virology ,medicine ,Immunoprecipitation ,Turnip mosaic virus ,MESH: Arabidopsis ,MESH: DNA Mutational Analysis ,COPII ,Sequence Deletion ,Arabidopsis Proteins ,MESH: Immunoprecipitation ,Endoplasmic reticulum ,MESH: Host-Pathogen Interactions ,MESH: Sequence Deletion ,biology.organism_classification ,MESH: Viral Proteins ,Virus-Cell Interactions ,Viral replication ,Coatomer ,Insect Science ,Host-Pathogen Interactions ,[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology - Abstract
Positive-sense RNA viruses remodel host cell endomembranes to generate quasi-organelles known as “viral factories” to coordinate diverse viral processes, such as genome translation and replication. It is also becoming clear that enclosing viral RNA (vRNA) complexes within membranous structures is important for virus cell-to-cell spread throughout the host. In plant cells infected by turnip mosaic virus (TuMV), a member of the family Potyviridae , peripheral motile endoplasmic reticulum (ER)-derived viral vesicles are produced that carry the vRNA to plasmodesmata for delivery into adjacent noninfected cells. The viral protein 6K 2 is responsible for the formation of these vesicles, but how 6K 2 is involved in their biogenesis is unknown. We show here that 6K 2 is associated with cellular membranes. Deletion mapping and site-directed mutagenesis experiments defined a soluble N-terminal 12-amino-acid stretch, in particular a potyviral highly conserved tryptophan residue and two lysine residues that were important for vesicle formation. When the tryptophan residue was changed into an alanine in the viral polyprotein, virus replication still took place, albeit at a reduced level, but cell-to-cell movement of the virus was abolished. Yeast ( Saccharomyces cerevisiae ) two-hybrid and coimmunoprecipitation experiments showed that 6K 2 interacted with Sec24a, a COPII coatomer component. Appropriately, TuMV systemic movement was delayed in an Arabidopsis thaliana mutant line defective in Sec24a. Intercellular movement of TuMV replication vesicles thus requires ER export of 6K 2 , which is mediated by the interaction of the N-terminal domain of the viral protein with Sec24a. IMPORTANCE Many plant viruses remodel the endoplasmic reticulum (ER) to generate vesicles that are associated with the virus replication complex. The viral protein 6K 2 of turnip mosaic virus (TuMV) is known to induce ER-derived vesicles that contain vRNA as well as viral and host proteins required for vRNA synthesis. These vesicles not only sustain vRNA synthesis, they are also involved in the intercellular trafficking of vRNA. In this investigation, we found that the N-terminal soluble domain of 6K 2 is required for ER export of the protein and for the formation of vesicles. ER export is not absolutely required for vRNA replication but is necessary for virus cell-to-cell movement. Furthermore, we found that 6K 2 physically interacts with the COPII coatomer Sec24a and that an Arabidopsis thaliana mutant line with a defective Sec24a shows a delay in the systemic infection by TuMV.
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- 2015
30. A survey of Populus PIN-FORMED family genes reveals their diversified expression patterns
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Bobin Liu, Jin Zhang, Mengzhu Lu, Huanquan Zheng, Lin Wang, Jun Chen, and Jianbo Li
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Physiology ,Secondary growth ,Plant Science ,Gene Expression Regulation, Plant ,Auxin ,Arabidopsis ,Botany ,Cambium ,PIN proteins ,Gene ,Phylogeny ,Plant Proteins ,chemistry.chemical_classification ,biology ,fungi ,Gene Expression Regulation, Developmental ,Membrane Transport Proteins ,food and beverages ,biology.organism_classification ,Cell biology ,Protein Transport ,Transmembrane domain ,Populus ,chemistry ,Multigene Family ,Plant hormone - Abstract
The plant hormone auxin is a key regulator of plant development, and its uneven distribution maintained by polar intercellular auxin transport in plant tissues can trigger a wide range of developmental processes. Although the roles of PIN-FORMED (PIN) proteins in intercellular auxin flow have been extensively characterized in Arabidopsis, their roles in woody plants remain unclear. Here, a comprehensive analysis of PIN proteins in Populus is presented. Fifteen PINs are encoded in the genome of Populus, including four PIN1s, one PIN2, two PIN3s, three PIN5s, three PIN6s, and two PIN8s. Similar to Arabidopsis AtPIN proteins, PtPINs share conserved topology and transmembrane domains, and are either plasma membrane- or endoplasmic reticulum-localized. The more diversified expansion of the PIN family in Populus, comparing to that in Arabidopsis, indicates that some auxin-regulated developmental processes, such as secondary growth, may exhibit unique features in trees. More importantly, different sets of PtoPINs have been found to be strongly expressed in the roots, leaves, and cambium in Populus; the dynamic expression patterns of selected PtoPINs were further examined during the regeneration of shoots and roots. This genome-wide analysis of the Populus PIN family provides important cues for their potential roles in tree growth and development.
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- 2014
31. ECERIFERUM11/C-TERMINAL DOMAIN PHOSPHATASE-LIKE2 Affects Secretory Trafficking.
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Lin Shi, Dean, Gillian H., Huanquan Zheng, Meents, Miranda J., Haslam, Tegan M., Haughn, George W., and Kunst, Ljerka
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- 2019
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32. Rab-A1c GTPase Defines a Population of the Trans-Golgi Network that Is Sensitive to Endosidin1 during Cytokinesis in Arabidopsis
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Huanquan Zheng and Xingyun Qi
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Limonins ,0106 biological sciences ,Vacuolar Proton-Translocating ATPases ,Green Fluorescent Proteins ,Meristem ,Population ,Arabidopsis ,Plant Science ,Biology ,01 natural sciences ,Wortmannin ,03 medical and health sciences ,symbols.namesake ,chemistry.chemical_compound ,Promoter Regions, Genetic ,education ,Mitosis ,Molecular Biology ,Cytokinesis ,Glucuronidase ,030304 developmental biology ,0303 health sciences ,education.field_of_study ,Arabidopsis Proteins ,fungi ,Cell plate ,Golgi apparatus ,Cell biology ,Transport protein ,Androstadienes ,Protein Transport ,chemistry ,rab GTP-Binding Proteins ,Mutation ,Vacuoles ,symbols ,Rab ,Subcellular Fractions ,trans-Golgi Network ,010606 plant biology & botany - Abstract
In plant cells, Rab-A proteins have been implicated to play important roles in membrane trafficking from the trans-Golgi network (TGN) to the plasma membrane/cell wall and to the newly formed cell plate in cytokinesis. But how different Rab-A proteins may work in the TGN is not well studied. We show here that RAB-A1c defines a population of TGN that is partially overlapped with the VHA-a1 marked-TGN. Interestingly, the morphology of RAB-A1c defined-TGN is sensitive to endosidin 1 (ES1), but not to wortmannin. In mitotic cells, RAB-A1c is relocated to the cell plate. We revealed that this process could be interrupted by ES1, but not by wortmannin. In addition, root growth and cytokinesis in root mitotic cells of rab-a1a/b/c triple mutant seedlings are hypersensitive to lower concentrations of ES1. ES1 is known to selectively block the transport of several plasma membrane auxin transporters, including PIN2 and AUX1 at the TGN. Together with the known facts that members of Rab-A1 proteins are involved in auxin-mediated responses in root growth and that mutations in TRAPPII, a protein complex that acts upstream of RAB-A1c, also selectively impair the transport of PIN2 and AUX1 at the TGN, we propose that the Rab-A1-mediated trafficking pathways around the TGN, but not Rab-A1s directly, are the target of ES1.
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- 2013
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33. An Integrated Bioinformatics Analysis Reveals Divergent Evolutionary Pattern of Oil Biosynthesis in High- and Low-Oil Plants
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Huanquan Zheng, Shibo Wang, Jian Song, Ling Zhou, Jim M. Dunwell, Yuan-Ming Zhang, Qi-Gang Li, Li Zhang, and Yu-Qi Hao
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0106 biological sciences ,0301 basic medicine ,lcsh:Medicine ,Gene Expression ,Plant Science ,01 natural sciences ,Genome ,Biochemistry ,Transcriptome ,Arabidopsis thaliana ,lcsh:Science ,Phylogeny ,Data Management ,Multidisciplinary ,biology ,Plant Anatomy ,food and beverages ,Agriculture ,Plants ,Lipids ,Seeds ,Research Article ,Computer and Information Sciences ,Crops ,03 medical and health sciences ,Phylogenetics ,Lipid biosynthesis ,Botany ,Genetics ,Plant Oils ,Grasses ,Gene ,Taxonomy ,lcsh:R ,Organisms ,Biology and Life Sciences ,Computational Biology ,Lipid metabolism ,Plant Taxonomy ,biology.organism_classification ,Lipid Metabolism ,Dicotyledons ,030104 developmental biology ,Metabolism ,lcsh:Q ,Oleosin ,Soybean ,Oils ,010606 plant biology & botany ,Crop Science - Abstract
Seed oils provide a renewable source of food, biofuel and industrial raw materials that is important for humans. Although many genes and pathways for acyl-lipid metabolism have been identified, little is known about whether there is a specific mechanism for high-oil content in high-oil plants. Based on the distinct differences in seed oil content between four high-oil dicots (20~50%) and three low-oil grasses (
- Published
- 2016
34. Viral Manipulation of Plant Host Membranes
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Huanquan Zheng, Jean-François Laliberté, Institut Armand Frappier (INRS-IAF), Institut National de la Recherche Scientifique [Québec] (INRS)-Réseau International des Instituts Pasteur (RIIP), Department of Biology [Montréal], and McGill University = Université McGill [Montréal, Canada]
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[SDV]Life Sciences [q-bio] ,viruses ,Cell ,Plasmodesma ,virus replication complexes ,Biology ,Virology ,Virus ,Cell biology ,virus movement ,medicine.anatomical_structure ,Viral envelope ,Viral entry ,Plant virus ,viral factories ,medicine ,cellular remodeling ,Intracellular ,Secretory pathway - Abstract
International audience; Plant viruses, like animal viruses, induce the formation of novel intracellular membranous structures that provide an optimum environment for coordinating diverse viral processes such as viral RNA synthesis and virus egress. Membrane reshaping is accomplished by the expression of specific membrane-associated viral proteins that interact with host proteins involved in membrane trafficking processes. Plant virus-induced membranous structures are motile, and this intracellular motility is required for the transport of viral RNA from sites of synthesis to plasmodesmata, which are used to move viral RNA from cell to cell. Cellular movement of these virus-induced bodies requires myosin motor activity and is dependent on the secretory pathway. The coupling of membrane-associated replication complexes with virus intra- and intercellular trafficking may explain why viral infection of neighboring cells is established rapidly and efficiently.
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- 2016
35. Subclass-Specific Localization and Trafficking of Arabidopsis p24 Proteins in the ER-Golgi Interface
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Huanquan Zheng, Jun Chen, and Xingyun Qi
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biology ,Vesicular-tubular cluster ,Endoplasmic reticulum ,Cell Biology ,COPI ,Golgi apparatus ,biology.organism_classification ,Subcellular localization ,Biochemistry ,Cell biology ,symbols.namesake ,Structural Biology ,Arabidopsis ,Genetics ,symbols ,Molecular Biology ,COPII ,Secretory pathway - Abstract
We describe a comprehensive analysis of the subcellular localization and in vivo trafficking of Arabidopsis p24 proteins. In Arabidopsis, there are 11 p24 proteins, which fall into only δ and β subfamilies. Interestingly, the δ subfamily of p24 proteins in Arabidopsis is elaborated spectacularly in evolution, which can be grouped into two subclasses: p24δ1 and p24δ2. We found that, although all p24δ proteins possess classic COPII/COPI binding motifs in their cytosolic C-termini, p24δ1 proteins are localized to the endoplasmic reticulum (ER), p24δ2 proteins are localized to both ER and Golgi. Two p24β proteins reside largely in Golgi. Similar to Atp24 (termed p24δ1c in this study), p24δ2d also cycles between the ER and Golgi. Interestingly, coexpression with p24β1 could retain p24δ2d, but not p24δ1d in Golgi. We revealed that the lumenal coiled-coil domain of p24δ2d is required for its steady-state localization in Golgi, probably through its interaction with p24β1. In p24β1, there is no classic COPII or COPI binding motif in its C-terminus. However, the protein also cycles between the ER and Golgi. We found that a conserved RV motif located at the extreme end of the C-terminus of p24β1 plays an important role in its Golgi target.
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- 2012
36. 6K2-induced vesicles can move cell to cell during turnip mosaic virus infection
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Huanquan Zheng, Jean-François Laliberté, Jun Jiang, Romain Grangeon, Juan Wan, Maxime Agbeci, Institut Armand Frappier (INRS-IAF), Institut National de la Recherche Scientifique [Québec] (INRS)-Réseau International des Instituts Pasteur (RIIP), Department of Biology [Montréal], McGill University = Université McGill [Montréal, Canada], and This study was supported by the Natural Sciences and Engineering Research Council of Canada and from Le Fonds de recherche du Québec – Nature et technologies to Huanquan Zheng and Jean-François Laliberté.
- Subjects
0106 biological sciences ,Microbiology (medical) ,viruses ,[SDV]Life Sciences [q-bio] ,Cell ,Potyvirus ,Plant RNA virus ,lcsh:QR1-502 ,membrane association ,Plasmodesma ,Biology ,01 natural sciences ,Microbiology ,intercellular movement ,lcsh:Microbiology ,Green fluorescent protein ,Cell wall ,03 medical and health sciences ,chemistry.chemical_compound ,RNA polymerase ,medicine ,Turnip mosaic virus ,replication complex ,Original Research Article ,030304 developmental biology ,0303 health sciences ,Vesicle ,biology.organism_classification ,Virology ,3. Good health ,medicine.anatomical_structure ,chemistry ,Intracellular ,010606 plant biology & botany - Abstract
International audience; To successfully infect plants, viruses replicate in an initially infected cell and then move to neighboring cells through plasmodesmata (PDs). However, the nature of the viral entity that crosses over the cell barrier into non-infected ones is not clear. The membrane-associated 6K2 protein of turnip mosaic virus (TuMV) induces the formation of vesicles involved in the replication and intracellular movement of viral RNA. This study shows that 6K2-induced vesicles trafficked toward the plasma membrane and were associated with plasmodesmata (PD). We demonstrated also that 6K2 moved cell-to-cell into adjoining cells when plants were infected with TuMV. 6K2 was then fused to photo-activable GFP (6K2:PAGFP) to visualize how 6K2 moved intercellularly during TuMV infection. After activation, 6K2:PAGFP-tagged vesicles moved to the cell periphery and across the cell wall into adjacent cells. These vesicles were shown to contain the viral RNA-dependent RNA polymerase and viral RNA. Symplasmic movement of TuMV may thus be achieved in the form of a membrane-associated viral RNA complex induced by 6K2.
- Published
- 2013
37. A specific role for Arabidopsis TRAPPII in post-Golgi trafficking that is crucial for cytokinesis and cell polarity
- Author
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Anja Geitmann, Huanquan Zheng, Minako Kaneda, Jun Chen, and Xingyun Qi
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biology ,Endoplasmic reticulum ,Cell Biology ,Plant Science ,Cell plate ,Vacuole ,Golgi apparatus ,biology.organism_classification ,Cell biology ,symbols.namesake ,Arabidopsis ,Cell polarity ,Genetics ,symbols ,Mitosis ,Cytokinesis - Abstract
Cytokinesis and cell polarity are supported by membrane trafficking from the trans-Golgi network (TGN), but the molecular mechanisms that promote membrane trafficking from the TGN are poorly defined in plant cells. Here we show that TRAPPII in Arabidopsis regulates the post-Golgi trafficking that is crucial for assembly of the cell plate and cell polarity. Disruptions of AtTRS120 or AtTRS130, two genes encoding two key subunits of TRAPPII, result in defective cytokinesis and cell polarity in embryogenesis and seedling development. In attrs120 and attrs130, the organization and trafficking in the endoplasmic reticulum (ER)-Golgi interface are normal. However, post-Golgi trafficking to the cell plate and to the cell wall, but not to the vacuole, is impaired. Furthermore, TRAPPII is required for the selective transport of PIN2, but not PIN1, to the plasma membrane. We revealed that AtTRS130 is co-localized with RAB-A1c. Expression of constitutively active RAB-A1c partially rescues attrs130. RAB-A1c, which resides at the TGN, is delocalized to the cytosol in attrs130. We propose that TRAPPII in Arabidopsis acts upstream of Rab-A GTPases in post-Golgi membrane trafficking in plant cells.
- Published
- 2011
38. Arabidopsis RHD3 mediates the generation of the tubular ER network and is required for Golgi distribution and motility in plant cells
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Huanquan Zheng, Giovanni Stefano, Jun Chen, and Federica Brandizzi
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Atlastin ,Blotting, Western ,Arabidopsis ,Golgi Apparatus ,Motility ,GTPase ,Root hair ,Endoplasmic Reticulum ,Plant Roots ,Polymerase Chain Reaction ,GTP Phosphohydrolases ,Plant Epidermis ,symbols.namesake ,Cell Movement ,GTP-Binding Proteins ,Tobacco ,Protein Isoforms ,biology ,Arabidopsis Proteins ,Endoplasmic reticulum ,Cell Biology ,Golgi apparatus ,biology.organism_classification ,Cell biology ,Plant Leaves ,Secretory protein ,Mutation ,Mutagenesis, Site-Directed ,symbols - Abstract
In plant cells, the endoplasmic reticulum (ER) and Golgi apparatus form a unique system in which single Golgi stacks are motile and in close association with the underlying ER tubules. Arabidopsis has three RHD3 (ROOT HAIR DEFECTIVE 3) isoforms that are analogous to the mammalian atlastin GTPases involved in shaping ER tubules. We used live-cell imaging, genetic complementation, split ubiquitin assays and western blot analyses in Arabidopsis and tobacco to show that RHD3 mediates the generation of the tubular ER network and is required for the distribution and motility of Golgi stacks in root and leaf epidermal cells. We established that RHD3 forms homotypic interactions at ER punctae. In addition, the activity of RHD3 on the tubular ER is specifically correlated with the cellular distribution and motility of Golgi stacks because ER to Golgi as well as Golgi to plasma membrane transport was not affected by RHD3 mutations in the conserved GDP/GTP motifs. We found a possible partial redundancy within the RHD3 isoforms in Arabidopsis. However, yeast Sey1p, a functional atlastin homologue, and RHD3 are not interchangeable in complementing the respective loss-of-function mutants, suggesting that the molecular mechanisms controlling ER tubular morphology might not be entirely conserved among eukaryotic lineages.
- Published
- 2011
39. Functional Characterization of the Arabidopsisβ-Ketoacyl-Coenzyme A Reductase Candidates of the Fatty Acid Elongase
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Frédéric Beaudoin, Johnathan A. Napier, Richard P. Haslam, Huanquan Zheng, Xianzhong Wu, Ljerka Kunst, Jonathan E. Markham, and Fengling Li
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Fatty Acid Elongases ,Physiology ,Coenzyme A ,Molecular Sequence Data ,Mutant ,Arabidopsis ,Plant Science ,Reductase ,Endoplasmic Reticulum ,chemistry.chemical_compound ,Acetyltransferases ,Genetics ,Protein Isoforms ,Arabidopsis thaliana ,chemistry.chemical_classification ,biology ,Arabidopsis Proteins ,Genetic Complementation Test ,Fatty acid ,biology.organism_classification ,Complementation ,Alcohol Oxidoreductases ,Mutagenesis, Insertional ,chemistry ,Biochemistry ,Seeds ,Fatty acid elongation ,RNA Interference ,Research Article - Abstract
In plants, very-long-chain fatty acids (VLCFAs; >18 carbon) are precursors of sphingolipids, triacylglycerols, cuticular waxes, and suberin. VLCFAs are synthesized by a multiprotein membrane-bound fatty acid elongation system that catalyzes four successive enzymatic reactions: condensation, reduction, dehydration, and a second reduction. A bioinformatics survey of the Arabidopsis (Arabidopsis thaliana) genome has revealed two sequences homologous to YBR159w encoding a Saccharomyces cerevisiae β-ketoacyl reductase (KCR), which catalyzes the first reduction during VLCFA elongation. Expression analyses showed that both AtKCR1 and AtKCR2 genes were transcribed in siliques, flowers, inflorescence stems, leaves, as well as developing embryos, but only AtKCR1 transcript was detected in roots. Fluorescent protein-tagged AtKCR1 and AtKCR2 were localized to the endoplasmic reticulum, the site of fatty acid elongation. Complementation of the yeast ybr159Δ mutant demonstrated that the two KCR proteins are divergent and that only AtKCR1 can restore heterologous elongase activity similar to the native yeast KCR gene. Analyses of insertional mutants in AtKCR1 and AtKCR2 revealed that loss of AtKCR1 function results in embryo lethality, which cannot be rescued by AtKCR2 expression using the AtKCR1 promoter. In contrast, a disruption of the AtKCR2 gene had no obvious phenotypic effect. Taken together, these results indicate that only AtKCR1 is a functional KCR isoform involved in microsomal fatty acid elongation. To investigate the roles of AtKCR1 in postembryonic development, transgenic lines expressing RNA interference and overexpression constructs targeted against AtKCR1 were generated. Morphological and biochemical characterization of these lines confirmed that suppressed KCR activity results in a reduction of cuticular wax load and affects VLCFA composition of sphingolipids, seed triacylglycerols, and root glycerolipids, demonstrating in planta that KCR is involved in elongation reactions supplying VLCFA for all these diverse classes of lipids.
- Published
- 2009
40. Identification of the Wax Ester Synthase/Acyl-Coenzyme A:Diacylglycerol Acyltransferase WSD1 Required for Stem Wax Ester Biosynthesis in Arabidopsis
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Reinhard Jetter, Patricia Lam, Huanquan Zheng, David Bird, Ljerka Kunst, Xuemin Wu, Lacey Samuels, and Fengling Li
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0106 biological sciences ,Physiology ,Coenzyme A ,Mutant ,Plant Science ,Biology ,01 natural sciences ,03 medical and health sciences ,chemistry.chemical_compound ,Biosynthesis ,Arabidopsis ,Genetics ,Arabidopsis thaliana ,030304 developmental biology ,0303 health sciences ,Wax ,ATP synthase ,food and beverages ,biology.organism_classification ,Wax ester ,Biochemistry ,chemistry ,visual_art ,visual_art.visual_art_medium ,biology.protein ,010606 plant biology & botany - Abstract
Wax esters are neutral lipids composed of aliphatic alcohols and acids, with both moieties usually long-chain (C16 and C18) or very-long-chain (C20 and longer) carbon structures. They have diverse biological functions in bacteria, insects, mammals, and terrestrial plants and are also important substrates for a variety of industrial applications. In plants, wax esters are mostly found in the cuticles coating the primary shoot surfaces, but they also accumulate to high concentrations in the seed oils of a few plant species, including jojoba (Simmondsia chinensis), a desert shrub that is the major commercial source of these compounds. Here, we report the identification and characterization of WSD1, a member of the bifunctional wax ester synthase/diacylglycerol acyltransferase gene family, which plays a key role in wax ester synthesis in Arabidopsis (Arabidopsis thaliana) stems, as first evidenced by severely reduced wax ester levels of in the stem wax of wsd1 mutants. In vitro assays using protein extracts from Escherichia coli expressing WSD1 showed that this enzyme has a high level of wax synthase activity and approximately 10-fold lower level of diacylglycerol acyltransferase activity. Expression of the WSD1 gene in Saccharomyces cerevisiae resulted in the accumulation of wax esters, but not triacylglycerol, indicating that WSD1 predominantly functions as a wax synthase. Analyses of WSD1 expression revealed that this gene is transcribed in flowers, top parts of stems, and leaves. Fully functional yellow fluorescent protein-tagged WSD1 protein was localized to the endoplasmic reticulum, demonstrating that biosynthesis of wax esters, the final products of the alcohol-forming pathway, occurs in this subcellular compartment.
- Published
- 2008
41. The Arabidopsis MUM2 Gene Encodes a β-Galactosidase Required for the Production of Seed Coat Mucilage with Correct Hydration Properties
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Gillian H. Dean, Jun Huang, Shawn D. Mansfield, Diana S. Young, Nicholas C. Carpita, Jagdish Tewari, Yeen Ting Hwang, George W. Haughn, Maureen C. McCann, Tamara L. Western, and Huanquan Zheng
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food.ingredient ,Pectin ,Recombinant Fusion Proteins ,Green Fluorescent Proteins ,Molecular Sequence Data ,Mutant ,Arabidopsis ,Carbonates ,Golgi Apparatus ,Plant Science ,Cell wall ,food ,Cell Wall ,Adhesives ,Spectroscopy, Fourier Transform Infrared ,Arabidopsis thaliana ,Research Articles ,Microscopy, Confocal ,biology ,Arabidopsis Proteins ,Reverse Transcriptase Polymerase Chain Reaction ,food and beverages ,Cell Biology ,Plants, Genetically Modified ,beta-Galactosidase ,biology.organism_classification ,Apoplast ,Plant Mucilage ,Mucilage ,Biochemistry ,Seeds ,Microscopy, Electron, Scanning ,Pectins - Abstract
Seed coat development in Arabidopsis thaliana involves a complex pathway where cells of the outer integument differentiate into a highly specialized cell type after fertilization. One aspect of this developmental process involves the secretion of a large amount of pectinaceous mucilage into the apoplast. When the mature seed coat is exposed to water, this mucilage expands to break the primary cell wall and encapsulate the seed. The mucilage-modified2 (mum2) mutant is characterized by a failure to extrude mucilage on hydration, although mucilage is produced as normal during development. The defect in mum2 appears to reside in the mucilage itself, as mucilage fails to expand even when the barrier of the primary cell wall is removed. We have cloned the MUM2 gene and expressed recombinant MUM2 protein, which has β-galactosidase activity. Biochemical analysis of the mum2 mucilage reveals alterations in pectins that are consistent with a defect in β-galactosidase activity, and we have demonstrated that MUM2 is localized to the cell wall. We propose that MUM2 is involved in modifying mucilage to allow it to expand upon hydration, establishing a link between the galactosyl side-chain structure of pectin and its physical properties.
- Published
- 2007
42. A Core Subunit of the RNA-Processing/Degrading Exosome Specifically Influences Cuticular Wax Biosynthesis inArabidopsis
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Huanquan Zheng, Ljerka Kunst, Tanya S. Hooker, and Patricia Lam
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Transcription, Genetic ,Protein subunit ,Molecular Sequence Data ,Mutant ,Arabidopsis ,Plant Science ,Cutin ,Biology ,Genes, Plant ,Plant Epidermis ,Gene Expression Regulation, Plant ,Transcription (biology) ,Yeast ribonuclease ,Exoribonuclease ,Amino Acid Sequence ,RNA, Messenger ,Cloning, Molecular ,Research Articles ,Phylogeny ,Messenger RNA ,Models, Genetic ,Plant Stems ,Arabidopsis Proteins ,Gene Expression Profiling ,Cell Biology ,biology.organism_classification ,Protein Subunits ,Phenotype ,Biochemistry ,Waxes ,Exoribonucleases ,Mutation - Abstract
The cuticle is an extracellular matrix composed of cutin polyester and waxes that covers aerial organs of land plants and protects them from environmental stresses. The Arabidopsis thaliana cer7 mutant exhibits reduced cuticular wax accumulation and contains considerably lower transcript levels of ECERIFERUM3/WAX2/YORE-YORE (CER3/WAX2/YRE), a key wax biosynthetic gene. We show here that CER7 protein is a putative 3′-5′ exoribonuclease homologous to yeast Ribonuclease PH45 (RRP45p), a core subunit of the RNA processing and degrading exosome that controls the expression of CER3/WAX2/YRE. We propose that CER7 acts by degrading a specific mRNA species encoding a negative regulator of CER3/WAX2/YRE transcription. A second RRP45p homolog found in Arabidopsis, designated At RRP45a, is partially functionally redundant with CER7, and complete loss of RRP45 function in Arabidopsis is lethal. To our knowledge, CER7 is currently the only example of a core exosomal subunit specifically influencing a cellular process.
- Published
- 2007
43. Turnip mosaic virus moves systemically through both phloem and xylem as membrane-associated complexes
- Author
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Huanquan Zheng, Juan Wan, Jean-François Laliberté, Daniel Garcia Cabanillas, Institut Armand Frappier (INRS-IAF), Institut National de la Recherche Scientifique [Québec] (INRS)-Réseau International des Instituts Pasteur (RIIP), Department of Biology [Montréal], McGill University = Université McGill [Montréal, Canada], and This work was supported by the Natural Sciences and Engineering Research Council of Canada and Le Fonds Québécois de Recherche sur la Nature et les Technologies (to H.Z. and J.-F.L.).
- Subjects
MESH: Brassica napus ,Physiology ,viruses ,[SDV]Life Sciences [q-bio] ,Plant Science ,Virus ,MESH: Xylem ,MESH: Plant Diseases ,MESH: Potyvirus ,Plant virus ,Genetics ,Turnip mosaic virus ,Endomembrane system ,MESH: Tobacco ,MESH: Plant Stems ,biology ,MESH: Plant Viruses ,fungi ,MESH: Virus Replication ,Xylem ,RNA ,food and beverages ,biology.organism_classification ,MESH: Viral Proteins ,Cell biology ,MESH: Phloem ,Biochemistry ,Viral replication ,MESH: RNA, Viral ,[SDV.MP.VIR]Life Sciences [q-bio]/Microbiology and Parasitology/Virology ,Phloem ,MESH: RNA Replicase - Abstract
International audience; Plant viruses move systemically in plants through the phloem. They move as virions or as ribonucleic protein complexes, although it is not clear what these complexes are made of. The approximately 10-kb RNA genome of Turnip mosaic virus (TuMV) encodes a membrane protein, known as 6K2, that induces endomembrane rearrangements for the formation of viral replication factories. These factories take the form of vesicles that contain viral RNA (vRNA) and viral replication proteins. In this study, we report the presence of 6K2-tagged vesicles containing vRNA and the vRNA-dependent RNA polymerase in phloem sieve elements and in xylem vessels. Transmission electron microscopy observations showed the presence in the xylem vessels of vRNA-containing vesicles that were associated with viral particles. Stem-girdling experiments, which leave xylem vessels intact but destroy the surrounding tissues, confirmed that TuMV could establish a systemic infection of the plant by going through xylem vessels. Phloem sieve elements and xylem vessels from Potato virus X-infected plants also contained lipid-associated nonencapsidated vRNA, indicating that the presence of membrane-associated ribonucleic protein complexes in the phloem and xylem may not be limited to TuMV. Collectively, these studies indicate that viral replication factories could end up in the phloem and the xylem.
- Published
- 2015
44. Hsf and Hsp gene families in Populus: genome-wide identification, organization and correlated expression during development and in stress responses
- Author
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Yan Wang, Huanquan Zheng, Mengzhu Lu, Jin Zhang, Bobin Liu, Li Zhang, Jun Chen, and Jianbo Li
- Subjects
endocrine system ,Transcription, Genetic ,Amino Acid Motifs ,Heat shock protein (Hsp) ,Biology ,Genes, Plant ,Bioinformatics ,Expression analysis ,Conserved sequence ,Gene Expression Regulation, Plant ,Stress, Physiological ,Gene Duplication ,Heat shock protein ,Arabidopsis ,Genetics ,Coexpression ,Gene family ,Gene Regulatory Networks ,Gene ,Conserved Sequence ,Phylogeny ,Regulation of gene expression ,Gene Expression Profiling ,fungi ,Chromosome Mapping ,biology.organism_classification ,Gene expression profiling ,Populus ,Organ Specificity ,Multigene Family ,Heat shock factor (Hsf) ,DNA microarray ,Genome, Plant ,Research Article ,Biotechnology - Abstract
Background Heat shock proteins (Hsps) are molecular chaperones that are involved in many normal cellular processes and stress responses, and heat shock factors (Hsfs) are the transcriptional activators of Hsps. Hsfs and Hsps are widely coordinated in various biological processes. Although the roles of Hsfs and Hsps in stress responses have been well characterized in Arabidopsis, their roles in perennial woody species undergoing various environmental stresses remain unclear. Results Here, a comprehensive identification and analysis of Hsf and Hsp families in poplars is presented. In Populus trichocarpa, we identified 42 paralogous pairs, 66.7% resulting from a whole genome duplication. The gene structure and motif composition are relatively conserved in each subfamily. Microarray and quantitative real-time RT-PCR analyses showed that most of the Populus Hsf and Hsp genes are differentially expressed upon exposure to various stresses. A coexpression network between Populus Hsf and Hsp genes was generated based on their expression. Coordinated relationships were validated by transient overexpression and subsequent qPCR analyses. Conclusions The comprehensive analysis indicates that different sets of PtHsps are downstream of particular PtHsfs and provides a basis for functional studies aimed at revealing the roles of these families in poplar development and stress responses. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1398-3) contains supplementary material, which is available to authorized users.
- Published
- 2015
45. CER4 Encodes an Alcohol-Forming Fatty Acyl-Coenzyme A Reductase Involved in Cuticular Wax Production in Arabidopsis
- Author
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Shelley R. Hepworth, Huanquan Zheng, Reinhard Jetter, Ljerka Kunst, Owen Rowland, and Patricia Lam
- Subjects
Reporter gene ,Wax ,biology ,Physiology ,Cuticle ,Coenzyme A ,Plant Science ,Cutin ,biology.organism_classification ,Complementation ,chemistry.chemical_compound ,Biochemistry ,chemistry ,Arabidopsis ,visual_art ,Genetics ,visual_art.visual_art_medium ,Arabidopsis thaliana - Abstract
A waxy cuticle that serves as a protective barrier against uncontrolled water loss and environmental damage coats the aerial surfaces of land plants. It is composed of a cutin polymer matrix and waxes. Cuticular waxes are complex mixtures of very-long-chain fatty acids and their derivatives. We report here the molecular cloning and characterization of CER4, a wax biosynthetic gene from Arabidopsis (Arabidopsis thaliana). Arabidopsis cer4 mutants exhibit major decreases in stem primary alcohols and wax esters, and slightly elevated levels of aldehydes, alkanes, secondary alcohols, and ketones. This phenotype suggested that CER4 encoded an alcohol-forming fatty acyl-coenzyme A reductase (FAR). We identified eight FAR-like genes in Arabidopsis that are highly related to an alcohol-forming FAR expressed in seeds of jojoba (Simmondsia chinensis). Molecular characterization of CER4 alleles and genomic complementation revealed that one of these eight genes, At4g33790, encoded the FAR required for cuticular wax production. Expression of CER4 cDNA in yeast (Saccharomyces cerevisiae) resulted in the accumulation of C24:0 and C26:0 primary alcohols. Fully functional green fluorescent protein-tagged CER4 protein was localized to the endoplasmic reticulum in yeast cells by confocal microscopy. Analysis of gene expression by reverse transcription-PCR indicated that CER4 was expressed in leaves, stems, flowers, siliques, and roots. Expression of a β-glucuronidase reporter gene driven by the CER4 promoter in transgenic plants was detected in epidermal cells of leaves and stems, consistent with a dedicated role for CER4 in cuticular wax biosynthesis. CER4 was also expressed in all cell types in the elongation zone of young roots. These data indicate that CER4 is an alcohol-forming FAR that has specificity for very-long-chain fatty acids and is responsible for the synthesis of primary alcohols in the epidermal cells of aerial tissues and in roots.
- Published
- 2006
46. Turnip Mosaic Virus Components Are Released into the Extracellular Space by Vesicles in Infected Leaves.
- Author
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Movahed, Nooshin, Cabanillas, Daniel Garcia, Juan Wan, Valid, Hojatollah, Laliberté, Jean-François, and Huanquan Zheng
- Published
- 2019
- Full Text
- View/download PDF
47. A Host ER Fusogen Is Recruited by Turnip Mosaic Virus for Maturation of Viral Replication Vesicles.
- Author
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Movahed, Nooshin, Jiaqi Sun, Vali, Hojatollah, Laliberté, Jean-François, and Huanquan Zheng
- Published
- 2019
- Full Text
- View/download PDF
48. A Rab-E GTPase Mutant Acts Downstream of the Rab-D Subclass in Biosynthetic Membrane Traffic to the Plasma Membrane in Tobacco Leaf Epidermis
- Author
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Patrick J. Hussey, Rui Malhó, Julia Legen, Henri Batoko, Edmund G. Wee, Luísa Camacho, Huanquan Zheng, Ian Moore, and Christopher J. Leaver
- Subjects
Yellow fluorescent protein ,Recombinant Fusion Proteins ,Green Fluorescent Proteins ,Mutant ,Golgi Apparatus ,Plant Science ,Vacuole ,Plant Epidermis ,symbols.namesake ,Bacterial Proteins ,Tobacco ,Research Articles ,Secretory pathway ,Plant Proteins ,biology ,Endoplasmic reticulum ,Cell Membrane ,fungi ,Intracellular Membranes ,Cell Biology ,Golgi apparatus ,Cell Compartmentation ,Cell biology ,Plant Leaves ,Luminescent Proteins ,Protein Transport ,Vacuolar pathway ,rab GTP-Binding Proteins ,Mutation ,Vacuoles ,biology.protein ,symbols ,Rab ,Signal Transduction - Abstract
The function of the Rab-E subclass of plant Rab GTPases in membrane traffic was investigated using a dominant-inhibitory mutant (RAB-E1d[NI]) of Arabidopsis thaliana RAB-E1d and in vivo imaging approaches that have been used to characterize similar mutants in the plant Rab-D2 and Rab-F2 subclasses. RAB-E1d[NI] inhibited the transport of a secreted green fluorescent protein marker, secGFP, but in contrast with dominant-inhibitory RAB-D2 or RAB-F2 mutants, it did not affect the transport of Golgi or vacuolar markers. Quantitative imaging revealed that RAB-E1d[NI] caused less intracellular secGFP accumulation than RAB-D2a[NI], a dominant-inhibitory mutant of a member of the Arabidopsis Rab-D2 subclass. Furthermore, whereas RAB-D2a[NI] caused secGFP to accumulate exclusively in the endoplasmic reticulum, RAB-E1d[NI] caused secGFP to accumulate additionally in the Golgi apparatus and a prevacuolar compartment that could be labeled by FM4-64 and yellow fluorescent protein (YFP)–tagged Arabidopsis RAB-F2b. Using the vacuolar protease inhibitor E64-d, it was shown that some secGFP was transported to the vacuole in control cells and in the presence of RAB-E1d[NI]. Consistent with the hypothesis that secGFP carries a weak vacuolar-sorting determinant, it was shown that a secreted form of DsRed reaches the apoplast without appearing in the prevacuolar compartment. When fused to RAB-E1d, YFP was targeted specifically to the Golgi via a saturable nucleotide- and prenylation-dependent mechanism but was never observed on the prevacuolar compartment. We propose that RAB-E1d[NI] inhibits the secretory pathway at or after the Golgi, causing an accumulation of secGFP in the upstream compartments and an increase in the quantity of secGFP that enters the vacuolar pathway.
- Published
- 2005
49. A GFP‐based assay reveals a role for RHD3 in transport between the endoplasmic reticulum and Golgi apparatus
- Author
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Chris Hawes, Huanquan Zheng, Ljerka Kunst, and Ian Moore
- Subjects
Cytochalasin B ,Green Fluorescent Proteins ,Arabidopsis ,Golgi Apparatus ,Plant Science ,Biology ,Endoplasmic Reticulum ,Green fluorescent protein ,chemistry.chemical_compound ,symbols.namesake ,GTP-Binding Proteins ,Genetics ,Secretion ,Endomembrane system ,Brefeldin A ,Arabidopsis Proteins ,Hydrolysis ,Endoplasmic reticulum ,Cell Biology ,Hydrogen-Ion Concentration ,Golgi apparatus ,Plants, Genetically Modified ,Apoplast ,Transport protein ,Cell biology ,Luminescent Proteins ,Protein Transport ,Biochemistry ,chemistry ,symbols - Abstract
We describe the use of a secreted form of Aequoria victoria green fluorescent protein (secGFP) in a non-invasive live cell assay of membrane traffic in Arabidopsis thaliana. We show that in comparison to GFP-HDEL, which accumulates in the endoplasmic reticulum (ER), secGFP generates a weak fluorescence signal when transported to the apoplast. The fluorescence of secGFP in the apoplast can be increased by growth of seedlings on culture medium buffered at pH 8.1, suggesting that apoplastic pH is responsible, at least in part, for the low fluorescence intensity of seedlings expressing secGFP. Inhibition of secGFP transport between the ER and plasma membrane (PM), either by Brefeldin A (BFA) treatment or by genetic intervention results in increased intracellular secGFP accumulation accompanied by an increase in the secGFP fluorescence intensity. secGFP thus provides a valuable tool for forward and reverse genetic analysis of membrane traffic and endomembrane organisation in Arabidopsis. Using this assay for quantitative sublethal perturbation of secGFP transport, we identify a role for root hair defective 3 (RHD3) in transport of secreted and Golgi markers between the ER and the Golgi apparatus.
- Published
- 2004
50. Intracellular localization and movement phenotypes of alfalfa mosaic virus movement protein mutants
- Author
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Lee Zhang, Huanquan Zheng, Mei Huang, John F. Bol, Laurian Jongejan, and Other departments
- Subjects
Genes, Viral ,Physiology ,Movement ,Mutant ,Green Fluorescent Proteins ,Gene Expression ,Biology ,Transfection ,Green fluorescent protein ,Viral Proteins ,Alfalfa mosaic virus ,Tobacco ,Movement protein ,Actin ,Cytoskeleton ,Epidermis (botany) ,Endoplasmic reticulum ,Protoplasts ,fungi ,General Medicine ,biology.organism_classification ,Plants, Genetically Modified ,Virology ,Cell biology ,Plant Leaves ,Plant Viral Movement Proteins ,Luminescent Proteins ,Phenotype ,Mutation ,RNA, Viral ,Agronomy and Crop Science - Abstract
Thirteen mutations were introduced in the movement protein (MP) gene of Alfalfa mosaic virus (AMV) fused to the green fluorescent protein (GFP) gene and the mutant MP-GFP fusions were expressed transiently in tobacco protoplasts, tobacco suspension cells, and epidermal cells of tobacco leaves. In addition, the mutations were introduced in the MP gene of AMV RNA 3 and the mutant RNAs were used to infect tobacco plants. Ten mutants were affected in one or more of the following functions of MP: the formation of tubular structures on the surface of protoplasts, association with the endoplasmic reticulum (ER) of suspension cells and epidermal cells, targeting to punctate structures in the cell wall of epidermis cells, movement from transfected cells to adjacent cells in epidermis tissue, cell-to-cell movement, or long-distance movement in plants. The mutations point to functional domains of the MP and support the proposed order of events in AMV transport. Studies with several inhibitors indicate that actin or microtubule components of the cytoskeleton are not involved in tubule formation by AMV MP. Evidence was obtained that tubular structures on the surface of transfected protoplasts contain ER- or plasmalemma-derived material.
- Published
- 2001
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