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Propylene-based elastomers (PBEs) have received widespread attention and research in recent years due to their structural diversity and excellent properties, and are also an important area for leading chemical companies to compete for layout, but efficient synthesis of PBEs remains challenging. In this paper, we review the development of PBEs and categorize them into three types, grounded in their unique chain structures, including homopolymer propylene-based elastomers (hPBEs), random copolymer propylene-based elastomers (rPBEs), and block copolymer propylene-based elastomers (bPBEs). The successful synthesis of these diverse PBEs is largely credited to the relentless innovative advancements in homogeneous catalysts (metallocene catalysts, constrained geometry catalysts, and non-metallocene catalysts). Consequently, we summarize the catalytic performance of various homogeneous catalysts employed in PBE synthesis and delve into their effect on molecular weight, molecular weight distribution, and chain structures of the resulting PBEs. In the end, based on the current academic research and industrialization status of PBEs, an outlook on potential future research directions for PBEs is provided.

Polyphenol oxidase (PPO) is a common metalloproteinase in plants with important roles in plant responses to abiotic and biotic stresses. There is evidence that PPOs contribute to stress responses in Paulownia fortunei. In this study, PPO gene family members in P. fortunei were comprehensively identified and characterized using bioinformatics methods as well as analyses of phylogenetic relationships, gene and protein structure, codon usage bias, and gene expression in response to stress. The genome contained 10 PPO gene family members encoding 406–593 amino acids, with a G/C bias. Most were localized in chloroplasts. The motif structure was conserved among family members, and α-helices and random coils were the dominant elements in the secondary structure. The promoters contained many cis-acting elements, such as auxin, gibberellin, salicylic acid, abscisic acid, and photoresponsive elements. The formation of genes in this family was linked to evolutionary events, such as fragment replication. Real-time quantitative PCR results showed that PfPPO7, PfPPO10, PfPPO1, PfPPO2, PfPPO3, PfPPO4, PfPPO5, and PfPPO8 may be key genes in drought stress resistance. PfPPO1, PfPPO3, PfPPO4, and PfPPO10 were resistant stress-sensitive genes. These results provide a reliable basis for fully understanding the potential functions of these genes and the selection of resistance breeding.

Abstract In the process of inflammatory activation, macrophages exhibit lipid metabolism disorders and accumulate lipid droplets. Kupffer cells (KCs) are the resident hepatic macrophage with critical defense functions in the pathogenesis of several types of liver disease. How dysregulated lipid metabolism contributes to perturbed KCs functions remains elusive. Here we report that glycerol-3-phosphate acyltransferase 3 (GPAT3) plays a key role in KCs inflammation response. Our findings indicate that lipopolysaccharide (LPS)-mediated inflammatory activation markedly increased lipid droplets (LDs) accumulation in KCs. This increase could be attributed to significantly up-regulated GPAT3. The loss of GPAT3 function obviously reduced KCs inflammation reaction both in vivo and in vitro, and was accompanied by improved mitochondrial function and decreased production of lysophosphatidic acid (LPA), in turn inhibiting extracellular regulated protein kinases (ERK) signaling pathway. Overall, this study highlights the role of GPAT3 in inflammatory activation of KCs and could thus be a potential therapeutic target for the treatment of inflammation-related liver disease.

In the realm of automated apple picking operations, the real-time monitoring of apple maturity and diameter characteristics is of paramount importance. Given the constraints associated with feature detection of apples in automated harvesting, this study proposes a machine vision-based methodology for the accurate identification of Fuji apples’ maturity and diameter. Firstly, maturity level detection employed an improved YOLOv5s object detection model. The feature fusion section of the YOLOv5s network was optimized by introducing the cross-level partial network module VoVGSCSP and lightweight convolution GSConv. This optimization aimed to improve the model’s multiscale feature information fusion ability while accelerating inference speed and reducing parameter count. Within the enhanced feature fusion network, a dual attention mechanism combining channel and spatial attention (GAM) was introduced to refine the color and texture feature information of apples and to increase spatial position feature weights. In terms of diameter determination, the contours of apples are obtained by integrating the dual features of color and depth images within the target boxes acquired using the maturity detection model. Subsequently, the actual area of the apple contour is determined by calculating the conversion relationship between pixel area and real area at the current depth value, thereby obtaining the diameter of the apples. Experimental results showed that the improved YOLOv5s model achieved an average maturity level detection precision of 98.7%. Particularly noteworthy was the detection accuracy for low maturity apples, reaching 97.4%, surpassing Faster R-CNN, Mask R-CNN, YOLOv7, and YOLOv5s models by 6.6%, 5.5%, 10.1%, and 11.0% with a real-time detection frame rate of 155 FPS. Diameter detection achieved a success rate of 93.3% with a real-time detection frame rate of 56 FPS and an average diameter deviation of 0.878 mm for 10 apple targets across three trials. Finally, the proposed method achieved an average precision of 98.7% for online detection of apple maturity level and 93.3% for fruit diameter features. The overall real-time inference speed was approximately 56 frames per second. These findings indicated that the method met the requirements of real-time mechanical harvesting operations, offering practical importance for the advancement of the apple industry.

Abstract Phytoplasmas induce diseases in more than 1000 plant species and cause substantial ecological damage and economic losses, but the specific pathogenesis of phytoplasma has not yet been clarified. N6‐methyladenosine (m6A) is the most common internal modification of the eukaryotic Messenger RNA (mRNA). As one of the species susceptible to phytoplasma infection, the pathogenesis and mechanism of Paulownia has been extensively studied by scholars, but the m6A transcriptome map of Paulownia fortunei (P. fortunei) has not been reported. Therefore, this study aimed to explore the effect of phytoplasma infection on m6A modification of P. fortunei and obtained the whole transcriptome m6A map in P. fortunei by m6A‐seq. The m6A‐seq results of Paulownia witches' broom (PaWB) disease and healthy samples indicate that PaWB infection increased the degree of m6A modification of P. fortunei. The correlation analysis between the RNA‐seq and m6A‐seq data detected that a total of 315 differentially methylated genes were predicted to be significantly differentially expressed at the transcriptome level. Moreover, the functions of PaWB‐related genes were predicted by functional enrichment analysis, and two genes related to maintenance of the basic mechanism of stem cells in shoot apical meristem were discovered. One of the genes encodes the receptor protein kinase CLV2 (Paulownia_LG2G000076), and the other gene encodes the homeobox transcription factor STM (Paulownia_LG15G000976). In addition, genes F‐box (Paulownia_LG17G000760) and MSH5 (Paulownia_LG8G001160) had exon skipping and mutually exclusive exon types of alternative splicing in PaWB‐infected seedling treated with methyl methanesulfonate, and m6A modification was found in m6A‐seq results. Moreover, Reverse Transcription–Polymerase Chain Reaction (RT‐PCR) verified that the alternative splicing of these two genes was associated with m6A modification. This comprehensive map provides a solid foundation for revealing the potential function of the mRNA m6A modification in the process of PaWB. In future studies, we plan to verify genes directly related to PaWB and methylation‐related enzymes in Paulownia to elucidate the pathogenic mechanism of PaWB caused by phytoplasma invasion.

For a fish tank of breeding vessels with perforated broadsides, in order to analyze its fluid characteristics under wave conditions, this paper presents a numerical method and predicts the fluid field in a fish tank with opening holes. Therein, three critical problems were solved, which include wave generation, the fluid–structure interaction of waves and vessel motion, and the sloshing phenomenon in the tank. The feasibility of the method was validated through a comparison with theoretical and experimental results. On this basis, the fluid characteristics in the fish tank of a fixed breeding vessel with opening holes on side walls were discussed. Firstly, the effects of wave direction, wave height, and wave period on the flow field in the tank were mainly analyzed. Next, the fluid characteristics in the tank of a floating vessel with opening holes equipping a multi-point mooring system were investigated. Finally, the influence of motion responses of breeding vessels on the fluid field in the fish tank was examined.

To learn about the gene structure, phylogenetic evolution, and function under biotic and abiotic stresses of BTB (Bric-a-Brac/Tramtrack/Broad Complex) genes in Paulownia fortunei, a whole-genome sequence evaluation was carried out, and a total of 62 PfBTB genes were identified. The phylogenetic analysis showed that PfBTB proteins are divided into eight groups, and these proteins are highly conserved. PfBTB genes were unevenly distributed on 17 chromosomes. The colinearity analysis found that fragment replication and tandem replication are the main modes of gene amplification in the PfBTB family. The analysis of cis-acting elements suggests that PfBTB genes may be involved in a variety of biological processes. The transcriptomic analysis results showed that PfBTB3/12/14/16/19/36/44 responded to Paulownia witches’ broom (PaWB), while PfBTB1/4/17/43 responded to drought stress, and the RT-qPCR results further support the reliability of transcriptome data. In addition, the association analysis between miRNA and transcriptome revealed a 91-pair targeting relationship between miRNAs and PfBTBs. In conclusion, the BTB genes in Paulownia are systematically identified in this research. This work provides useful knowledge to more fully appreciate the potential functions of these genes and their possible roles in the occurrence of PaWB and in response to stress.

The introduction of polar functional groups into polyolefin chain structures creates opportunities to enhance specific properties, such as adhesion, dyeability, printability, compatibility, thermal stability, and electrical conductivity, which widen the range of potential applications for these modified materials. Transition metal catalysts, especially late transition metals, have proven to be highly effective in copolymerization processes due to their reduced Lewis acidity and electrophilicity. However, when compared to the significant progress and summary of synthetic methods, there is a distinct lack of a comprehensive summary of mechanistic studies pertaining to the catalytic systems involved in ethylene copolymerization catalyzed by palladium and nickel catalysts. In this review, we have provided a comprehensive summary of the latest developments in mechanistic studies of ethylene copolymerization with polar monomers catalyzed by late-transition-metal complexes. Experimental and computational methods were employed to conduct a detailed investigation of these organic and organometallic systems. It is mainly focused on ligand substitution, changes in binding modes, ethylene/polar monomer insertion, chelate opening, and β-H elimination. Factors that control the catalytic activity, molecular weight, comonomer incorporation ratios, and branch content are analyzed, these include steric repulsions between ligands and monomers, electronic effects arising from both ligands and monomers, and so on.

To address the issues of low efficiency and high damage rates during apple harvesting and packing, a parameter optimization experiment was conducted on a low-damage packing device for an apple harvesting platform based on Adams 2019 software. The aim was to reduce the mechanical damage to apples during the packing process. Firstly, kinematics and energetics analyses of the apple packing process were performed, and a mathematical model for damage energy was established to identify the main factors and their ranges that influence the mechanical damage to apples. Secondly, using the fruit damage rate and packing efficiency as the evaluation criteria, a second-order orthogonal rotating regression experiment was conducted with the inclination angle of the fruit conveying tube, the inner wall radius of the fruit conveying tube, and the length of the fruit conveying tube as the experimental factors. Regression mathematical models were established to assess the relationship between the evaluation criteria and the experimental factors. Finally, the impact of each experimental factor on the evaluation criteria was analyzed to determine the optimal structural parameters for the low-damage packing device of the apple harvesting platform, and validation experiments were conducted. The results showed that when the inclination angle of the fruit conveying tube was 47°, the inner wall radius of the fruit conveying tube was 84 mm and the length of the fruit conveying tube was 0.12 m, the average fruit damage rate was minimized at 7.2%, and the average packing efficiency was maximized at 1925 kg/h. These results meet the requirements for apple harvesting operations, and the research findings can serve as a reference for the structural design and packing operation parameter optimization of apple harvesting platforms.

DHA/AA alleviated LPS-induced Kupffer cells pyroptosis via GPR120 interaction with NLRP3 to inhibit NLRP3 inflammasome assembly.

Abstract Background Paulownia withes’-broom (PaWB) disease caused by phytoplasma is a serious infectious disease for Paulownia. However, the underlying molecular pathogenesis is not fully understood. Recent studies have demonstrated that histone modifications could play a role in plant defense responses to pathogens. But there is still no available genome-wide histone modification data in non-model ligneous species infected with phytoplasma. Results Here, we provided the first genome-wide profiles of three histone marks (H3K4me3, H3K36me3 and H3K9ac) in Paulownia fortunei under phytoplasma stress by using chromatin immunoprecipitation sequencing (ChIP-Seq). We found that H3K4me3, H3K36me3 and H3K9ac were mainly enriched in the genic regions in P. fortunei with (PFI) and without (PF) phytoplasma infection. ChIP-Seq analysis revealed 1738, 986, and 2577 genes were differentially modified by H3K4me3, H3K36me3 and H3K9ac marks in PFI under phytoplasma infection, respectively. The functional analysis of these genes suggested that most of them were mainly involved in metabolic pathways, biosynthesis of secondary metabolites, phenylpropanoid biosynthesis, plant-pathogen interaction and plant hormone signal transduction. In addition, the combinational analysis of ChIP-Seq and RNA-Seq showed that differential histone methylation and acetylation only affected a small subset of phytoplasma-responsive genes. Conclusions Taken together, this is the first report of integrated analysis of histone modifications and gene expression involved in Paulownia-phytoplasma interaction. Our results will provide the valuable resources for the mechanism studies of gene regulation in non-model plants upon pathogens attack.

Pentachloronitrobenzene (PCNB) is an organochlorine protective fungicide mainly used as a soil and seed fungicide. Currently, there are few reports on the toxicity of PCNB to zebrafish embryo. Here, we evaluated the toxicity of PCNB in aquatic vertebrates using a zebrafish model. Exposure of zebrafish embryos to PCNB at concentrations of 0.25 mg/L, 0.5 mg/L, and 0.75 mg/L from 6 hpf to 72 hpf resulted in abnormal embryonic development, including cardiac malformation, pericardial edema, decreased heart rate, decreased blood flow velocity, deposition at yolk sac, shortened body length, and increased distance between venous sinus and arterial bulb (SV-BA). The expression of genes related to cardiac development was disordered. However, due to the unstable embryo status in the 0.75 mg/L exposure concentration group, the effect of PCNB on the expression levels of cardiac-related genes was not concentration-dependent. We found that PCNB increased reactive oxygen species stress levels in zebrafish, increased malondialdehyde (MDA) content and catalase (CAT) activity, and decreased superoxide dismutase (SOD) activity. The increased level of oxidative stress reduced the proliferation ability of zebrafish cardiomyocytes, and the expressions of zebrafish proliferation-related genes such as cdk-2, cdk-6, ccnd1, and ccne1 were significantly down-regulated. Astaxanthin (AST) attenuates PCNB-induced reduction in zebrafish cardiomyocyte proliferation by reducing oxidative stress levels. Our study shows that PCNB can cause severe oxidative stress in zebrafish, thereby reducing the proliferative capacity of cardiomyocytes, resulting in zebrafish cardiotoxicity.

Abstract Polyploidy in plants can bestow long-term evolutionary flexibility and resistance to biotic and abiotic stresses. The upstream activation mechanisms of salt response remain unknown. Here we integrated transcriptome, miRNA and proteome data to describe the link between abscisic acid (ABA)-effectors and salt resistance against the background of Paulownia genome. Combing GO and KEGG pathway annotation of differentially expressed genes and proteins, as well as differentially expressed miRNA, these results reflect endogenous signal ABA activate the downstream effectors, such as ion channel effectors and oxido-reduction effectors, to maintain the homeostasis of Paulownia’s growth. The cascaded metabolic network involved ABA biosynthesis, signaling transduction and the response of effectors. Our results will contribute to a comprehensive understanding of the genetic basis of salt tolerance, which may help to expand the available arable land for P. fortunei cultivation.

Paulownia witches’ broom caused by phytoplasma infection affects the production of Paulownia trees worldwide. Emerging evidence showed that long noncoding RNAs (lncRNA) play a protagonist role in regulating the expression of genes in plants. So far, the identification of lncRNAs has been limited to a few model plant species, and their roles in mediating responses to Paulownia tomentosa that free of phytoplasma infection are yet to be characterized. Here, whole-genome identification of lncRNAs, based on strand-specific RNA sequencing, from four Paulownia tomentosa samples, was performed and identified 3689 lncRNAs. These lncRNAs showed low conservation among plant species and some of them were miRNA precursors. Further analysis revealed that the 112 identified lncRNAs were related to phytoplasma infection. We predicted the target genes of these phytoplasma-responsive lncRNAs, and our analysis showed that 51 of the predicted target genes were alternatively spliced. Moreover, we found the expression of the lncRNAs plays vital roles in regulating the genes involved in the reactive oxygen species induced hypersensitive response and effector-triggered immunity in phytoplasma-infected Paulownia. This study indicated that diverse sets of lncRNAs were responsive to Paulownia witches’ broom, and the results will provide a starting point to understand the functions and regulatory mechanisms of Paulownia lncRNAs in the future.

Paulownia witches’ broom (PaWB) disease caused by phytoplasma is a fatal disease that leads to considerable economic losses. Although there are a few reports describing studies of PaWB pathogenesis, the molecular mechanisms underlying phytoplasma pathogenicity in Paulownia trees remain uncharacterized. In this study, after building a transcriptome database containing 67,177 sequences, we used isobaric tags for relative and absolute quantification (iTRAQ) to quantify and analyze the proteome-level changes among healthy P. fortunei (PF), PaWB-infected P. fortunei (PFI), and PaWB-infected P. fortunei treated with 20 mg L−1 or 60 mg L−1 methyl methane sulfonate (MMS) (PFI-20 and PFI-60, respectively). A total of 2,358 proteins were identified. We investigated the proteins profiles in PF vs. PFI (infected process) and PFI-20 vs. PFI-60 (recovered process), and further found that many of the MMS-response proteins mapped to “photosynthesis” and “ribosome” pathways. Based on our comparison scheme, 36 PaWB-related proteins were revealed. Among them, 32 proteins were classified into three functional groups: (1) carbohydrate and energy metabolism, (2) protein synthesis and degradation, and (3) stress resistance. We then investigated the PaWB-related proteins involved in the infected and recovered processes, and discovered that carbohydrate and energy metabolism was inhibited, and protein synthesis and degradation decreased, as the plant responded to PaWB. Our observations may be useful for characterizing the proteome-level changes that occur at different stages of PaWB disease. The data generated in this study may serve as a valuable resource for elucidating the pathogenesis of PaWB disease during phytoplasma infection and recovery stages.

Understanding the role of miRNAs in regulating the molecular mechanisms responsive to drought stress was studied in Paulownia “yuza 1.” Two small RNA libraries and two degradome libraries were, respectively, constructed and sequenced in order to detect miRNAs and their target genes associated with drought stress. A total of 107 miRNAs and 42 putative target genes were identified in this study. Among them, 77 miRNAs were differentially expressed between drought-treated Paulownia “yuza 1” and the control (60 downregulated and 17 upregulated). The predicted target genes were annotated using the GO, KEGG, and Nr databases. According to the functional classification of the target genes, Paulownia “yuza 1” may respond to drought stress via plant hormone signal transduction, photosynthesis, and osmotic adjustment. Furthermore, the expression levels of seven miRNAs (ptf-miR157b, ptf-miR159b, ptf-miR398a, ptf-miR9726a, ptf-M2153, ptf-M2218, and ptf-M24a) and their corresponding target genes were validated by quantitative real-time PCR. The results provide relevant information for understanding the molecular mechanism of Paulownia resistance to drought and reference data for researching drought resistance of other trees.

Polyploidy events are believed to be responsible for increasing the size of plant organs and enhancing tolerance to environmental stresses. Autotetraploid Paulownia australis plants exhibit superior traits compared with their diploid progenitors. Although some transcriptomics studies have been performed and some relevant genes have been revealed, the molecular and biological mechanisms regulating the predominant characteristics and the effects of polyploidy events on P. australis remain unknown. In this study, we compared the phenotypes, microstructures, and proteomes of autotetraploid and diploid P. australis plants. Compared with the diploid plant, the leaves of the autotetraploid plant were longer and wider, and the upper epidermis, lower epidermis, and palisade layer of the leaves were thicker, the leaf spongy parenchyma layer was thinner, the leaf cell size was bigger, and cell number was lower. In the proteome analysis, 3,010 proteins were identified and quantified, including 773 differentially abundant proteins. These results may help to characterize the P. australis proteome profile. Differentially abundant proteins related to cell division, glutathione metabolism, and the synthesis of cellulose, chlorophyll, and lignin were more abundant in the autotetraploid plants. These results will help to enhance the understanding of variations caused by polyploidy events in P. australis. The quantitative real-time PCR results provided details regarding the expression patterns of the proteins at mRNA level. We observed a limited correlation between transcript and protein levels. These observations may help to clarify the molecular basis for the predominant autotetraploid characteristics and be useful for plant breeding in the future.

Paulownia tomentosa is a fast-growing tree species with multiple uses. It is grown worldwide, but is native to China, where it is widely cultivated in saline regions. We previously confirmed that autotetraploid P. tomentosa plants are more stress-tolerant than the diploid plants. However, the molecular mechanism underlying P. tomentosa salinity tolerance has not been fully characterized. Using the complete Paulownia fortunei genome as a reference, we applied next-generation RNA-sequencing technology to analyze the effects of salt stress on diploid and autotetraploid P. tomentosa plants. We generated 175 million clean reads and identified 15,873 differentially expressed genes (DEGs) from four P. tomentosa libraries (two diploid and two autotetraploid). Functional annotations of the differentially expressed genes using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases revealed that plant hormone signal transduction and photosynthetic activities are vital for plant responses to high-salt conditions. We also identified several transcription factors, including members of the AP2/EREBP, bHLH, MYB, and NAC families. Quantitative real-time PCR analysis validated the expression patterns of eight differentially expressed genes. Our findings and the generated transcriptome data may help to accelerate the genetic improvement of cultivated P. tomentosa and other plant species for enhanced growth in saline soils.

Paulownia fortunei is a widely cultivated economic forest tree species that is susceptible to infection with phytoplasma, resulting in Paulownia witches’ broom (PaWB) disease. Diseased P. fortunei is characterized by stunted growth, witches’ broom, shortened internodes, and etiolated and smaller leaves. To understand the molecular mechanism of its pathogenesis, we applied isobaric tags for relative and absolute quantitation (iTRAQ) and liquid chromatography coupled with tandem mass spectrometry approaches to study changes in the proteomes of healthy P. fortunei, PaWB-infected P. fortunei, and PaWB-infected P. fortunei treated with 15 mg·L−1 or 75 mg·L−1 dimethyl sulfate. We identified 2969 proteins and 104 and 32 differentially abundant proteins that were phytoplasma infection responsive and dimethyl sulfate responsive, respectively. Based on our analysis of the different proteomes, 27 PaWB-related proteins were identified. The protein-protein interactions of these 27 proteins were analyzed and classified into four groups (photosynthesis-related, energy-related, ribosome-related, and individual proteins). These PaWB-related proteins may help in developing a deeper understanding of how PaWB affects the morphological characteristics of P. fortunei and further establish the mechanisms involved in the response of P. fortunei to phytoplasma.

Exposure to high salinity can trigger acclimation in many plants. Such an adaptative response is greatly advantageous for plants and involves extensive reprogramming at the molecular level. Acclimation allows plants to survive in environments that are prone to increasing salinity. In this study, diploid and autotetraploid Paulownia fortunei seedlings were used to detect alterations in leaf proteins in plants under salt stress. Up to 152 differentially abundant proteins were identified by Multiplex run iTRAQ-based quantitative proteomic and LC-MS/MS methods. Bioinformatics analysis suggested that P. fortunei leaves reacted to salt stress through a combination of common responses, such as induced metabolism, signal transduction, and regulation of transcription. This study offers a better understanding of the mechanisms of salt tolerance in P. fortunei and provides a list of potential target genes that could be engineered for salt acclimation in plants, especially trees.

MicroRNAs (miRNAs) are small, non-coding RNAs that play vital roles in plant growth, development, and stress response. Increasing numbers of studies aimed at discovering miRNAs and analyzing their functions in plants are being reported. In this study, we investigated the effect of drought stress on the expression of miRNAs and their targets in plants of a diploid and derived autotetraploid Paulownia australis. Four small RNA (sRNA) libraries and four degradome libraries were constructed from diploid and autotetraploid P. australis plants treated with either 75% or 25% relative soil water content. A total of 33 conserved and 104 novel miRNAs (processing precision value > 0.1) were identified, and 125 target genes were identified for 36 of the miRNAs by using the degradome sequencing. Among the identified miRNAs, 54 and 68 were differentially expressed in diploid and autotetraploid plants under drought stress (25% relative soil water content), respectively. The expressions of miRNAs and target genes were also validated by quantitative real-time PCR. The results showed that the relative expression trends of the randomly selected miRNAs were similar to the trends predicted by Illumina sequencing. And the correlations between miRNAs and their target genes were also analyzed. Furthermore, the functional analysis showed that most of these miRNAs and target genes were associated with plant development and environmental stress response. This study provided molecular evidence for the possible involvement of certain miRNAs in the drought response and/or tolerance in P. australis, and certain level of differential expression between diploid and autotetraploid plants.

Salt stress is a global environmental problem that affects plant growth and development. Paulownia fortunei is an adaptable and fast-growing deciduous tree native to China that is environmentally and economically important. MicroRNAs (miRNAs) play important regulatory roles in growth, development, and stress responses in plants. MiRNAs that respond to biotic stresses have been identified; however, how miRNAs in P. fortunei respond to salt stress has not yet been reported. To identify salt-stress-responsive miRNAs and predict their target genes, four small RNA and four degradome libraries were constructed from NaCl-treated and NaCl-free leaves of P. fortunei seedlings. The results indicated that salt stress had different physiological effects on diploid and tetraploid P. fortunei. We detected 53 conserved miRNAs belonging to 17 miRNA families and 134 novel miRNAs in P. fortunei. Comparing their expression levels in diploid and tetraploid P. fortunei, we found 10 conserved and 10 novel miRNAs that were significantly differentially expressed under salt treatment, among them eight were identified as miRNAs probably associated with higher salt tolerance in tetraploid P. fortunei than in diploid P. fortunei. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed to predict the functions of the target genes of the conserved and novel miRNAs. The expressions of 10 differentially expressed miRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR). This is the first report on P. fortunei miRNAs and their target genes under salt stress. The results provided information at the physiological and molecular levels for further research into the response mechanisms of P. fortunei to salt stress.

Paulownia witches' broom (PaWB) caused by a phytoplasma, has caused extensive losses in the yields of paulownia timber and resulted in significant economic losses. However, the molecular mechanisms in Paulownia that underlie the phytoplasma stress are poorly characterized. In this study, we use an Illumina platform to sequence four small RNA libraries and four degradome sequencing libraries derived from healthy, PaWB-infected, and PaWB-infected 15 mg·L-1 and 30 mg·L-1 methyl methane sulfonate (MMS)-treated plants. In total, 125 conserved and 118 novel microRNAs (miRNAs) were identified and 33 miRNAs responsive to PaWB disease were discovered. Furthermore, 166 target genes for 18 PaWB disease-related miRNAs were obtained, and found to be involved in plant-pathogen interaction and plant hormone signal transduction metabolic pathways. Eleven miRNAs and target genes responsive to PaWB disease were examined by a quantitative real-time PCR approach. Our findings will contribute to studies on miRNAs and their targets in Paulownia, and provide new insights to further understand plant-phytoplasma interactions.

MicroRNAs (miRNAs) are involved in plant growth, development, and response to biotic and abiotic stresses. Most of the miRNAs that have been identified in model plants are well characterized, but till now, no reports have previously been published concerning miRNAs in Paulownia australis. In order to investigate miRNA-guided transcript target regulation in P. australis, small RNA libraries from two P. australis (diploids, PA2; and autotetraploids, PA4) genotypes were subjected to Solexa sequencing. As a result, 10,691,271 (PA2) and 10,712,733 (PA4) clean reads were obtained, and 45 conserved miRNAs belonging to 15 families, and 31 potential novel miRNAs candidates were identified. Compared with their expression levels in the PA2 plants, 26 miRNAs were up-regulated and 15 miRNAs were down-regulated in the PA4 plants. The relative expressions of 12 miRNAs were validated by quantitative real-time polymerase chain reaction. Using the degradome approach, 53 transcript targets were identified and annotated based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis. These targets were associated with development, stimulus response, metabolism, signaling transduction and biological regulation. Among them, 11 targets, including TCP transcription factors, auxin response factors, squamosa promoter-binding-like proteins, scarecrow-like proteins, L-type lectin-domain containing receptor kinases and zinc finger CCCH domain-containing protein, cleaved by four known miRNA family and two potentially novel miRNAs were found to be involved in regulating plant development, biotic and abiotic stresses. The findings will be helpful to facilitate studies on the functions of miRNAs and their transcript targets in Paulownia.

Paulownia is a fast-growing deciduous hardwood species native to China, which has high ecological and economic value. In an earlier study, we reported ploidy-dependent differences in Paulownia drought tolerance by the microscopic observations of the leaves. Autotetraploid Paulownia has a higher resistance to drought stress than their diploid relatives. In order to obtain genetic information on molecular mechanisms responses of Paulownia plants to drought, Illumina/Solexa Genome sequencing platform was used to de novo assemble the transcriptomes of leaves from diploid and autotetraploid Paulownia tomentosa × Paulownia fortunei seedlings (PTF2 and PTF4 respectively) grown under control conditions and under drought stress and obtained 98,671 nonredundant unigenes. A comparative transcriptome analysis revealed that hundreds of unigenes were predicted to be involved mainly in ROS-scavenging system, amino acid and carbohydrate metabolism, plant hormone biosynthesis and signal transduction, while these unigenes exhibited differential transcript alteration of the two accessions. This study provides a comprehensive map of how P. tomentosa × P. fortunei responds to drought stress at physiological and molecular levels, which may help in understanding the mechanisms involve in water-deficit response and will be useful for further study of drought tolerance in woody plants.

Paulownia witches' broom (PaWB) caused by phytoplasma might result in devastating damage to the growth and wood production of Paulownia. To study the effect of phytoplasma on DNA sequence and to discover the genes related to PaWB occurrence, DNA polymorphisms and DNA methylation levels and patterns in PaWB seedlings, the ones treated with various concentration of methyl methane sulfonate (MMS) and healthy seedlings were investigated with amplified fragment length polymorphism (AFLP) and methylation-sensitive amplification polymorphism (MSAP). Our results indicated that PaWB seedlings recovered a normal morphology, similar to healthy seedlings, after treatment with more than 20 mg · L-1 MMS; Phytoplasma infection did not change the Paulownia genomic DNA sequence at AFLP level, but changed the global DNA methylation levels and patterns; Genes related to PaWB were discovered through MSAP and validated using quantitative real-time PCR (qRT-PCR). These results implied that changes of DNA methylation levels and patterns were closely related to the morphological changes of seedlings infected with phytoplasmas.

In spite of its economic importance, very little molecular genetics and genomic research has been targeted at the family Paulownia spp. The little genetic information on this plant is a big obstacle to studying the mechanisms of its ability to resist Paulownia Witches' Broom (PaWB) disease. Analysis of the Paulownia transcriptome and its expression profile data are essential to extending the genetic resources on this species, thus will greatly improves our studies on Paulownia. In the current study, we performed the de novo assembly of a transcriptome on P. tomentosa × P. fortunei using the short-read sequencing technology (Illumina). 203,664 unigenes with a mean length of 1,328 bp was obtained. Of these unigenes, 32,976 (30% of all unigenes) containing complete structures were chosen. Eukaryotic clusters of orthologous groups, gene orthology, and the Kyoto Encyclopedia of Genes and Genomes annotations were performed of these unigenes. Genes related to PaWB disease resistance were analyzed in detail. To our knowledge, this is the first study to elucidate the genetic makeup of Paulownia. This transcriptome provides a quick way to understanding Paulownia, increases the number of gene sequences available for further functional genomics studies and provides clues to the identification of potential PaWB disease resistance genes. This study has provided a comprehensive insight into gene expression profiles at different states, which facilitates the study of each gene's roles in the developmental process and in PaWB disease resistance.

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[Objectives] To screen a new wheat variety suitable for planting in southern Shandong Province. [Methods] The DTOPSIS based on entropy weighting was used to comprehensively evaluate 9 traits of 19 wheat varieties planted in southern Shandong Province. [Results] The weight of each indicator from low to high was growth period < yield < bulk density < plant height < effective panicle < basic seedling < 1 000-grain weight < heading rate < number of grains per panicle. The C, value of 6 varieties were greater than 0.5, specifically, 0.922 1 for Shannong HH126, 0.868 for DK171,0.851 5 for Hemai 179, 0.719 6 for Feida6, 0.6967 for Jinlai 36 and 0.523 2 for Yannong 301. [Conclusions] The comprehensive traits of these six wheat varieties are good, and they are suitable for planting in southern Shandong Province. [ABSTRACT FROM AUTHOR]

Somatic embryogenesis receptor-like kinases (SERKs) are receptor-like proteins that contain leucine-rich repeats and are involved in various signaling pathways. This study identified SERK family members in the Paulownia fortunei genome and analyzed their characteristics and expression profiles using bioinformatics methods. We identified 12 SERK genes with relatively conserved gene structures and motifs that were distributed unevenly on eight Paulownia chromosomes. The gene promoters contained various cis-acting elements that regulated the expression of the PfSERK genes in response to hormones and abiotic stresses. Synteny analysis indicated that 10 segmental duplication events had occurred during evolution of the PfSERK family. The expression profile of PfSERKs in various tissues of Paulownia fortunei was detected by quantitative real-time PCR (qRT-PCR). Many PfSERK genes can respond to drought and salt stress. Combined with RNA-seq and protein interaction network, it is speculated that PfSERK3/11 may participate in the occurrence of Paulownia witches' broom (PaWB) by regulating the plant height of Paulownia. [ABSTRACT FROM AUTHOR]