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DREB transcription factor can significantly improve the plant resistance to drought, high salt, low temperature, high temperature, and other abiotic stress. A previous study showed that DREB transcription factor gene GmDREB3 from soybean can improve drought resistance in tobacco, however, whether it can improve drought resistance in wheat needs to be further investigated. In the present study, GmDREB3 was transferred to a wheat variety, Shi366 and two positive lines of the T5 generation were obtained by additive culture and molecular identification. GmDREB3‐OE (overexpression) lines conferred drought tolerance characteristics, including higher survival rates, lower malondialdehyde (MDA) content, lower relative conductivity, higher chlorophyll content, and higher proline content than Shi366 wheat plants under drought stress. The SPAD, Fv/Fm, panicle number, and grain yield of GmDREB3‐OE lines were increased but the transpiration rate was decreased, compared to the Shi366 plants in the field condition under drought stress. Significant differences in the stress indices were observed between the GmDREB3–OE lines and Shi366 wheat plants, which suggested that the GmDREB3 significantly improved wheat tolerance to drought stress. In addition, RT‐qPCR analysis indicated that GmDREB3 could enhance the expression of drought‐related genes in wheat. Therefore, GmDREB3 significantly increased drought tolerance in wheat plants along with improved physiological and agronomic traits and grain yield. [ABSTRACT FROM AUTHOR]

Tubby-like proteins (TLPs) are transcription factors that are widely present in eukaryotes and generally participate in growth and developmental processes. Using genome databases, a total of 22 putative TLP genes were identified in the soybean genome, and unevenly distributed across 13 chromosomes. Phylogenetic analysis demonstrated that the predicted GmTLP proteins were divided into five groups (I-V). Gene structure, protein motifs, and conserved domains were analyzed to identify differences and common features among the GmTLPs. A three-dimensional protein model was built to show the typical structure of TLPs. Analysis of publicly available gene expression data showed that GmTLP genes were differentially expressed in response to abiotic stresses. Based on those data, GmTLP8 was selected to further explore the role of TLPs in soybean drought and salt stress responses. GmTLP8 overexpressors had improved tolerance to drought and salt stresses, whereas the opposite was true of GmTLP8 -RNAi lines. 3,3-diaminobenzidine and nitro blue tetrazolium staining and physiological indexes also showed that overexpression of GmTLP8 enhanced the tolerance of soybean to drought and salt stresses; in addition, downstream stress-responsive genes were upregulated in response to drought and salt stresses. This study provides new insights into the function of GmTLPs in response to abiotic stresses. [ABSTRACT FROM AUTHOR]

TIFY proteins play crucial roles in plant abiotic and biotic stress responses. Our transcriptome data revealed several TIFY family genes with significantly upregulated expression under drought, salt, and ABA treatments. However, the functions of the GmTIFY family genes are still unknown in abiotic stresses. We identified 38 GmTIFY genes and found that TIFY10 homologous genes have the most duplication events, higher selection pressure, and more obvious response to abiotic stresses compared with other homologous genes. Expression pattern analysis showed that GmTIFY10e and GmTIFY10g genes were significantly induced by salt stress. Under salt stress, GmTIFY10e and GmTIFY10g transgenic Arabidopsis plants showed higher root lengths and fresh weights and had significantly better growth than the wild type (WT). In addition, overexpression of GmTIFY10e and GmTIFY10g genes in soybean improved salt tolerance by increasing the PRO, POD, and CAT contents and decreasing the MDA content; on the contrary, RNA interference plants showed sensitivity to salt stress. Overexpression of GmTIFY10e and GmTIFY10g in Arabidopsis and soybean could improve the salt tolerance of plants, while the RNAi of GmTIFY10e and GmTIFY10g significantly increased sensitivity to salt stress in soybean. Further analysis demonstrated that GmTIFY10e and GmTIFY10g genes changed the expression levels of genes related to the ABA signal pathway, including GmSnRK2 , GmPP2C , GmMYC2 , GmCAT1 , and GmPOD. This study provides a basis for comprehensive analysis of the role of soybean TIFY genes in stress response in the future. [ABSTRACT FROM AUTHOR]

DEAD-box RNA helicases constitute the largest subfamily of RNA helicase superfamily 2 (SF2), and play crucial roles in plant growth, development, and abiotic stress responses. Wheat is one of the most important cereal crops in worldwide, and abiotic stresses greatly restrict its production. So far, the DEAD-box RNA helicase family has yet to be characterized in wheat. Here, we performed a comprehensive genome-wide analysis of the DEAD-box RNA helicase family in wheat, including phylogenetic relationships, chromosomal distribution, duplication events, and protein motifs. A total of 141 TaDEAD-box genes were identified and found to be unevenly distributed across all 21 chromosomes. Whole genome/segmental duplication was identified as the likely main driving factor for expansion of the TaDEAD-box family. Expression patterns of the 141 TaDEAD-box genes were compared across different tissues and under abiotic stresses to identify genes to be important in growth or stress responses. TaDEAD-box57-3B was significantly up-regulated under multiple abiotic stresses, and was therefore selected for further analysis. TaDEAD-box57-3B was localized to the cytoplasm and plasma membrane. Ectopic expression of TaDEAD-box57-3B in Arabidopsis improved tolerance to drought and salt stress as measured by germination rates, root lengths, fresh weights, and survival rates. Transgenic lines also showed higher levels of proline and chlorophyll and lower levels of malonaldehyde (MDA) than WT plants in response to drought or salt stress. In response to cold stress, the transgenic lines showed significantly better growth and higher survival rates than WT plants. These results indicate that TaDEAD-box57-3B may increase tolerance to drought, salt, and cold stress in transgenic plants through regulating the degree of membrane lipid peroxidation. This study provides new insights for understanding evolution and function in the TaDEAD-box gene family. [ABSTRACT FROM AUTHOR]

Phospholipase C (PLC) performs significant functions in a variety of biological processes, including plant growth and development. The PLC family of enzymes principally catalyze the hydrolysis of phospholipids in organisms. This exhaustive exploration of soybean GmPLC members using genome databases resulted in the identification of 15 phosphatidylinositol-specific PLC (GmPI-PLC) and 9 phosphatidylcholine-hydrolyzing PLC (GmNPC) genes. Chromosomal location analysis indicated that GmPLC genes mapped to 10 of the 20 soybean chromosomes. Phylogenetic relationship analysis revealed that GmPLC genes distributed into two groups in soybean, the PI-PLC and NPC groups. The expression patterns and tissue expression analysis showed that GmPLCs were differentially expressed in response to abiotic stresses. GmPI-PLC7 was selected to further explore the role of PLC in soybean response to drought and salt stresses by a series of experiments. Compared with the transgenic empty vector (EV) control lines, over-expression of GmPI-PLC7 (OE) conferred higher drought and salt tolerance in soybean, while the GmPI-PLC7 -RNAi (RNAi) lines exhibited the opposite phenotypes. Plant tissue staining and physiological parameters observed from drought- and salt-stressed plants showed that stress increased the contents of chlorophyll, oxygen free radical (O2–), hydrogen peroxide (H2O2) and NADH oxidase (NOX) to amounts higher than those observed in non-stressed plants. This study provides new insights in the functional analysis of GmPLC genes in response to abiotic stresses. [ABSTRACT FROM AUTHOR]

Plant C2 domain proteins play essential biological functions in numerous plants. In this study, 180 soybean C2 domain genes were identified by screening. Phylogenetic relationship analysis revealed that C2 domain genes fell into three distinct groups with diverged gene structure and conserved functional domain. Chromosomal location analysis indicated that C2 domain genes mapped to 20 chromosomes. The transcript profiles based on RNA-seq data showed that GmC2-58 , GmC2-88 , and GmC2-148 had higher levels of expression under salt, drought, and abscisic acid (ABA) treatments. GmC2-148 , encoding a cell membrane-localized protein, had the highest level of response to various treatments according to real-time quantitative polymerase chain reaction (RT-qPCR) analysis. Under salt and drought stresses, the soybean plants with GmC2-148 transgenic hairy roots showed delayed leaf rolling, a higher content of proline (Pro), and lower contents of H2O2, O2– and malondialdehyde (MDA) compared to those of the empty vector (EV) plants. The results of transgenic Arabidopsis in salt and drought treatments were consistent with those in soybean treatments. In addition, the soybean plants with GmC2-148 transgenic hairy roots increased transcript levels of several abiotic stress-related marker genes, including COR47 , NCDE3 , NAC11 , WRKY13, DREB2A , MYB84 , bZIP44 , and KIN1 which resulted in enhanced abiotic stress tolerance in soybean. These results indicate that C2 domain genes are involved in response to salt and drought stresses, and this study provides a genome-wide analysis of the C2 domain family in soybean. [ABSTRACT FROM AUTHOR]

GRAS genes, which form a plant-specific transcription factor family, play an important role in plant growth and development and stress responses. However, the functions of GRAS genes in soybean (Glycine max) remain largely unknown. Here, 117 GRAS genes distributed on 20 chromosomes were identified in the soybean genome and were classified into 11 subfamilies. Of the soybean GRAS genes, 80.34% did not have intron insertions, and 54 pairs of genes accounted for 88.52% of duplication events (61 pairs). RNA-seq analysis demonstrated that most GmGRASs were expressed in 14 different soybean tissues examined and responded to multiple abiotic stresses. Results from quantitative real-time PCR analysis of six selected GmGRASs suggested that GmGRAS37 was significantly upregulated under drought and salt stress conditions and abscisic acid and brassinosteroid treatment; therefore, this gene was selected for further study. Subcellular localization analysis revealed that the GmGRAS37 protein was located in the plasma membrane, nucleus, and cytosol. Soybean hairy roots overexpressing GmGRAS37 had improved resistance to drought and salt stresses. In addition, these roots showed increased transcript levels of several drought‐ and salt-related genes. The results of this study provide the basis for comprehensive analysis of GRAS genes and insight into the abiotic stress response mechanism in soybean. [ABSTRACT FROM AUTHOR]

Background: Crop productivity is challenged by abiotic stresses, among which drought stress is the most common. NF-Y genes, especially NF-YA genes, regulate tolerance to abiotic stress. Results: Soybean NF-Y gene GmNFYA5 was identified to have the highest transcript level among all 21 NF-YA genes in soybean (Glycine max L.) under drought stress. Drought-induced transcript of GmNFYA5 was suppressed by the ABA synthesis inhibitor naproxen (NAP). GmNFYA5 transcript was detected in various tissues at vegetative and reproductive growth stages with higher levels in roots and leaves than in other tissues, which was consist with the GmNFYA5 promoter: GUS fusion assay. Overexpression of GmNFYA5 in transgenic Arabidopsis plants caused enhanced drought tolerance in seedlings by decreasing stomatal aperture and water loss from leaves. Overexpression and suppression of GmNFYA5 in soybean resulted in increased and decreased drought tolerance, respectively, relative to plants with an empty vector (EV). Transcript levels of ABA-dependent genes (ABI2, ABI3, NCED3, LEA3, RD29A, P5CS1, GmWRKY46, GmNCED2 and GmbZIP1) and ABA-independent genes (DREB1A, DREB2A, DREB2B, GmDREB1, GmDREB2 and GmDREB3) in transgenic plants overexpressing GmNFYA5 were higher than those of wild-type plants under drought stress; suppression of GmNFYA5 transcript produced opposite results. GmNFYA5 probably regulated the transcript abundance of GmDREB2 and GmbZIP1 by binding to the promoters in vivo. Conclusions: Our results suggested that overexpression of GmNFYA5 improved drought tolerance in soybean via both ABA-dependent and ABA-independent pathways. [ABSTRACT FROM AUTHOR]

Stress associated proteins (SAPs) containing A20/AN1 zinc finger domains have emerged as novel regulators of stress responses. In this study, 27 SAP genes were identified in soybean. The phylogenetic relationships, exon–intron structure, domain structure, chromosomal localization, putative cis -acting elements, and expression patterns of SAPs in various tissues under abiotic stresses were analyzed. Among the soybean SAP genes, GmSAP1 6 was significantly induced by water deficit stress, salt, and abscisic acid (ABA) and selected for further analysis. GmSAP16 was located in the nucleus and cytoplasm. The overexpression of GmSAP16 in Arabidopsis improved drought and salt tolerance at different developmental stages and increased ABA sensitivity, as indicated by delayed seed germination and stomatal closure. The GmSAP16 transgenic Arabidopsis plants had a higher proline content and a lower water loss rate and malondialdehyde (MDA) content than wild type (WT) plants in response to stresses. The overexpression of GmSAP16 in soybean hairy roots enhanced drought and salt tolerance of soybean seedlings, with higher proline and chlorophyll contents and a lower MDA content than WT. RNA inference (RNAi) of GmSAP16 increased stress sensitivity. Stress-related genes, including GmDREB1B;1 , GmNCED3 , GmRD22 , GmDREB2 , GmNHX1 , and GmSOS1 , showed significant expression alterations in GmSAP16 -overexpressing and RNAi plants under stress treatments. These results indicate that soybean SAP genes play important roles in abiotic stress responses. [ABSTRACT FROM AUTHOR]

Abscisic acid (ABA) mediates various abiotic stress responses, and ethylene responsive factors (ERFs) play vital role in resisting stresses, but the interaction of these molecular mechanisms remains elusive. In this study, we identified an ABA-induced soybean ERF gene GmERF135 that was highly up-regulated by ethylene (ET), drought, salt, and low temperature treatments. Subcellular localization assay showed that the GmERF135 protein was targeted to the nucleus. Promoter cis -acting elements analysis suggested that numerous potential stress responsive cis -elements were distributed in the promoter region of GmERF135 , including ABA-, light-, ET-, gibberellin (GA)-, and methyl jasmonate (MeJA)-responsive elements. Overexpression of GmERF135 in Arabidopsis enhanced tolerance to drought and salt conditions. In addition, GmERF135 promoted the growth of transgenic hairy roots under salt and exogenous ABA conditions. These results suggest that soybean GmERF135 may participate in both ABA and ET signaling pathways to regulate the responses to multiple stresses. [ABSTRACT FROM AUTHOR]

The TGA transcription factors, a subfamily of bZIP group D, play crucial roles in various biological processes, including the regulation of growth and development as well as responses to pathogens and abiotic stress. In this study, 27 TGA genes were identified in the soybean genome. The expression patterns of GmTGA genes showed that several GmTGA genes are differentially expressed under drought and salt stress conditions. Among them, GmTGA17 was strongly induced by both stress, which were verificated by the promoter-GUS fusion assay. GmTGA17 encodes a nuclear-localized protein with transcriptional activation activity. Heterologous and homologous overexpression of GmTGA17 enhanced tolerance to drought and salt stress in both transgeinc Arabidopsis plants and soybean hairy roots. However, RNAi hairy roots silenced for GmTGA17 exhibited an increased sensitivity to drought and salt stress. In response to drought or salt stress, transgenic Arabidopsis plants had an increased chlorophyll and proline contents, a higher ABA content, a decreased MDA content, a reduced water loss rate, and an altered expression of ABA- responsive marker genes compared with WT plants. In addition, transgenic Arabidopsis plants were more sensitive to ABA in stomatal closure. Similarly, measurement of physiological parameters showed an increase in chlorophyll and proline contents, with a decrease in MDA content in soybean seedlings with overexpression hairy roots after drought and salt stress treatments. The opposite results for each measurement were observed in RNAi lines. This study provides new insights for functional analysis of soybean TGA transcription factors in abiotic stress. [ABSTRACT FROM AUTHOR]

The phytohormone abscisic acid (ABA) plays crucial roles in adaptive responses of plants to abiotic stresses. ABA-responsive element binding proteins (AREBs) are basic leucine zipper transcription factors that regulate the expression of downstream genes containing ABA-responsive elements (ABREs) in promoter regions. A novel ABI-like (ABA-insensitive) transcription factor gene, named TaABL1, containing a conserved basic leucine zipper (bZIP) domain was cloned from wheat. Southern blotting showed that three copies were present in the wheat genome. Phylogenetic analyses indicated that TaABL1 belonged to the AREB subfamily of the bZIP transcription factor family and was most closely related to ZmABI5 in maize and OsAREB2 in rice. Expression of TaABL1 was highly induced in wheat roots, stems, and leaves by ABA, drought, high salt, and low temperature stresses. TaABL1 was localized inside the nuclei of transformed wheat mesophyll protoplast. Overexpression of TaABL1 enhanced responses of transgenic plants to ABA and hastened stomatal closure under stress, thereby improving tolerance to multiple abiotic stresses. Furthermore, overexpression of TaABL1 upregulated or downregulated the expression of some stress-related genes controlling stomatal closure in transgenic plants under ABA and drought stress conditions, suggesting that TaABL1 might be a valuable genetic resource for transgenic molecular breeding. [ABSTRACT FROM AUTHOR]

Vascular plant one-zinc-finger (VOZ) transcription factor, a plant specific one-zinc-finger-type transcriptional activator, is involved in regulating numerous biological processes such as floral induction and development, defense against pathogens, and response to multiple types of abiotic stress. Six VOZ transcription factor-encoding genes (GmVOZs) have been reported to exist in the soybean (Glycine max) genome. In spite of this, little information is currently available regarding GmVOZs. In this study, GmVOZs were cloned and characterized. GmVOZ genes encode proteins possessing transcriptional activation activity in yeast cells. GmVOZ1E, GmVOZ2B, and GmVOZ2D gene products were widely dispersed in the cytosol, while GmVOZ1G was primarily located in the nucleus. GmVOZs displayed a differential expression profile under dehydration, salt, and salicylic acid (SA) stress conditions. Among them, GmVOZ1G showed a significantly induced expression in response to all stress treatments. Overexpression of GmVOZ1G in soybean hairy roots resulted in a greater tolerance to drought and salt stress. In contrast, RNA interference (RNAi) soybean hairy roots suppressing GmVOZ1G were more sensitive to both of these stresses. Under drought treatment, soybean composite plants with an overexpression of hairy roots had higher relative water content (RWC). In response to drought and salt stress, lower malondialdehyde (MDA) accumulation and higher peroxidase (POD) and superoxide dismutase (SOD) activities were observed in soybean composite seedlings with an overexpression of hairy roots. The opposite results for each physiological parameter were obtained in RNAi lines. In conclusion, GmVOZ1G positively regulates drought and salt stress tolerance in soybean hairy roots. Our results will be valuable for the functional characterization of soybean VOZ transcription factors under abiotic stress. [ABSTRACT FROM AUTHOR]

Plants have a series of response mechanisms to adapt when they are subjected to external stress. Calcium-dependent protein kinases (CDPKs) in plants function against a variety of abiotic stresses. We screened 17 CDPKs from drought- and salt-induced soybean transcriptome sequences. The phylogenetic tree divided CDPKs of rice, Arabidopsis and soybean into five groups (I–V). Cis-acting element analysis showed that the 17 CDPKs contained some elements associated with drought and salt stresses. Quantitative real-time PCR (qRT-PCR) analysis indicated that the 17 CDPKs were responsive after different degrees of induction under drought and salt stresses. GmCDPK3 was selected as a further research target due to its high relative expression. The subcellular localization experiment showed that GmCDPK3 was located on the membrane of Arabidopsis mesophyll protoplasts. Overexpression of GmCDPK3 improved drought and salt resistance in Arabidopsis. In the soybean hairy roots experiment, the leaves of GmCDPK3 hairy roots with RNA interference (GmCDPK3-RNAi) soybean lines were more wilted than those of GmCDPK3 overexpression (GmCDPK3-OE) soybean lines after drought and salt stresses. The trypan blue staining experiment further confirmed that cell membrane damage of GmCDPK3-RNAi soybean leaves was more severe than in GmCDPK3-OE soybean lines. In addition, proline (Pro) and chlorophyll contents were increased and malondialdehyde (MDA) content was decreased in GmCDPK3-OE soybean lines. On the contrary, GmCDPK3-RNAi soybean lines had decreased Pro and chlorophyll content and increased MDA. The results indicate that GmCDPK3 is essential in resisting drought and salt stresses. [ABSTRACT FROM AUTHOR]

Pentatricopeptide-repeat (PPR) proteins were identified as a type of nucleus coding protein that is composed of multiple tandem repeats. It has been reported that PPR genes play an important role in RNA editing, plant growth and development, and abiotic stresses in plants. However, the functions of PPR proteins remain largely unknown in soybean. In this study, 179 DYW subgroup PPR genes were identified in soybean genome (Glycine max Wm82.a2.v1). Chromosomal location analysis indicated that DYW subgroup PPR genes were mapped to all 20 chromosomes. Phylogenetic relationship analysis revealed that DYW subgroup PPR genes were categorized into three distinct Clusters (I to III). Gene structure analysis showed that most PPR genes were featured by a lack of intron. Gene duplication analysis demonstrated 30 PPR genes (15 pairs; ~35.7%) were segmentally duplicated among Cluster I PPR genes. Furthermore, we validated the mRNA expression of three genes that were highly up-regulated in soybean drought- and salt-induced transcriptome database and found that the expression levels of GmPPR4 were induced under salt and drought stresses. Under drought stress condition, GmPPR4-overexpressing (GmPPR4-OE) plants showed delayed leaf rolling; higher content of proline (Pro); and lower contents of H2O2, O2− and malondialdehyde (MDA) compared with the empty vector (EV)-control plants. GmPPR4-OE plants exhibited increased transcripts of several drought-inducible genes compared with EV-control plants. Our results provided a comprehensive analysis of the DYW subgroup PPR genes and an insight for improving the drought tolerance in soybean. [ABSTRACT FROM AUTHOR]

Summary Sterols have long been associated with diverse fields, such as cancer treatment, drug development, and plant growth; however, their underlying mechanisms and functions remain enigmatic. Here, we unveil a critical role played by a GmNF‐YC9‐mediated CCAAT‐box transcription complex in modulating the steroid metabolism pathway within soybeans. Specifically, this complex directly activates squalene monooxygenase (GmSQE1), which is a rate‐limiting enzyme in steroid synthesis. Our findings demonstrate that overexpression of either GmNF‐YC9 or GmSQE1 significantly enhances soybean stress tolerance, while the inhibition of SQE weakens this tolerance. Field experiments conducted over two seasons further reveal increased yields per plant in both GmNF‐YC9 and GmSQE1 overexpressing plants under drought stress conditions. This enhanced stress tolerance is attributed to the reduction of abiotic stress‐induced cell oxidative damage. Transcriptome and metabolome analyses shed light on the upregulation of multiple sterol compounds, including fucosterol and soyasaponin II, in GmNF‐YC9 and GmSQE1 overexpressing soybean plants under stress conditions. Intriguingly, the application of soybean steroids, including fucosterol and soyasaponin II, significantly improves drought tolerance in soybean, wheat, foxtail millet, and maize. These findings underscore the pivotal role of soybean steroids in countering oxidative stress in plants and offer a new research strategy for enhancing crop stress tolerance and quality from gene regulation to chemical intervention. [ABSTRACT FROM AUTHOR]

Growing evidence indicates that elongation factor 1α (EF1α) is involved in responses to various abiotic stresses in several plant species. Soybean EF1α proteins include three structural domains: one GTP-binding domain and two oligonucleotide binding domains that are also called as domain 2 and domain 3. In this study, 10 EF1α genes were identified in the soybean genome. We predicted structures of different domains and analyzed gene locations, gene structures, phylogenetic relationships, various cis-elements, and conserved domains of soybean EF1αs. The expression patterns of 10 EF1α genes were analyzed by quantitative real-time PCR (qRT-PCR). Under drought stress, soybean EF1α genes were upregulated in varying degrees. In particular, GmEF4 was upregulated under drought and salt treatments. Compared to the drought- and salt-treated empty vector (EV)-control plants, drought- and salt-treated GmEF4-overexpressing (OE) plants had significantly delayed leaf wilting, longer root, higher biomass, higher proline (Pro) content, and lower H2O2, O2−, and malondialdehyde (MDA) contents. Thus, this study provides a foundation for further functional genomics research about this important family under abiotic stress. [ABSTRACT FROM AUTHOR]

LIM proteins have been found to play important roles in many life activities, including the regulation of gene expression, construction of the cytoskeleton, signal transduction and metabolic regulation. Because of their important roles in many aspects of plant development, LIM genes have been studied in many plant species. However, the LIM gene family has not yet been characterized in foxtail millet. In this study, we analyzed the whole genome of foxtail millet and identified 10 LIM genes. All LIM gene promoters contain MYB and MYC cis-acting elements that are related to drought stress. Based on the presence of multiple abiotic stress-related cis-elements in the promoter of SiWLIM2b, we chose this gene for further study. We analyzed SiWLIM2b expression under abiotic stress and hormone treatments using qRT-PCR. We found that SiWLIM2b was induced by various abiotic stresses and hormones. Under drought conditions, transgenic rice of SiWLIM2b-overexpression had a higher survival rate, higher relative water content and less cell damage than wild type (WT) rice. These results indicate that overexpression of the foxtail millet SiWLIM2b gene enhances drought tolerance in transgenic rice, and the SiWLIM2b gene can potentially be used for molecular breeding of crops with increased resistance to abiotic stress. [ABSTRACT FROM AUTHOR]

Melatonin (N-acetyl-5-methoxytryptamine) is involved in many developmental processes and responses to various abiotic stresses in plants. Most of the studies on melatonin focus on its functions and physiological responses in plants, while its regulation mechanism remains unknown. Caffeic acid 3-O-methyltransferase (COMT) functions at a key step of the biosynthesis process of melatonin. In this study, a COMT-like gene, TaCOMT (Traes_1AL_D9035D5E0.1) was identified in common wheat (Triticum aestivum L.). Transient transformation in wheat protoplasts determined that TaCOMT is localized in cytoplasm. TaCOMT in wheat was induced by drought stress, gibberellin (GA)3 and 3-Indoleacetic acid (IAA), but not by ABA. In TaCOMT transgenic Arabidopsis, melatonin contents were higher than that in wild type (WT) plants. Under D-Mannitol treatment, the fresh weight of the transgenic Arabidopsis was significantly higher than WT, and transgenic lines had a stronger root system compared to WT. Drought tolerance assays in pots showed that the survival rate of TaCOMT-overexpression lines was significantly higher than that of WT lines. this phenotype was similar to that the WT lines treated with melatonin under drought condition. In addition, the TaCOMT transgenic lines had higher proline content and lower malondialdehyde (MDA) content compared to WT lines after drought treatment. These results indicated that overexpression of the wheat TaCOMT gene enhances drought tolerance and increases the content of melatonin in transgenic Arabidopsis. It could be one of the potential genes for agricultural applications. [ABSTRACT FROM AUTHOR]

Background: Abiotic stress severely influences plant growth and development. MYB transcription factors (TFs), which compose one of the largest TF families, play an important role in abiotic stress responses. Result: We identified 139 soybean MYB-related genes; these genes were divided into six groups based on their conserved domain and were distributed among 20 chromosomes (Chrs). Quantitative real-time PCR (qRT-PCR) indicated that GmMYB118 highly responsive to drought, salt and high temperature stress; thus, this gene was selected for further analysis. Subcellular localization revealed that the GmMYB118 protein located in the nucleus. Ectopic expression (EX) of GmMYB118 increased tolerance to drought and salt stress and regulated the expression of several stress-associated genes in transgenic Arabidopsis plants. Similarly, GmMYB118-overexpressing (OE) soybean plants generated via Agrobacterium rhizogenes (A. rhizogenes)-mediated transformation of the hairy roots showed improved drought and salt tolerance. Furthermore, compared with the control (CK) plants, the clustered, regularly interspaced, short palindromic repeat (CRISPR)-transformed plants exhibited reduced drought and salt tolerance. The contents of proline and chlorophyll in the OE plants were significantly greater than those in the CK plants, whose contents were greater than those in the CRISPR plants under drought and salt stress conditions. In contrast, the reactive oxygen species (ROS) and malondialdehyde (MDA) contents were significantly lower in the OE plants than in the CK plants, whose contents were lower than those in the CRISPR plants under stress conditions. Conclusions: These results indicated that GmMYB118 could improve tolerance to drought and salt stress by promoting expression of stress-associated genes and regulating osmotic and oxidizing substances to maintain cell homeostasis. [ABSTRACT FROM AUTHOR]

Abiotic stresses restrict the growth and yield of crops. Plants have developed a number of regulatory mechanisms to respond to these stresses. WRKY transcription factors (TFs) are plant-specific transcription factors that play essential roles in multiple plant processes, including abiotic stress response. At present, little information regarding drought-related WRKY genes in maize is available. In this study, we identified a WRKY transcription factor gene from maize, named ZmWRKY40. ZmWRKY40 is a member of WRKY group II, localized in the nucleus of mesophyll protoplasts. Several stress-related transcriptional regulatory elements existed in the promoter region of ZmWRKY40. ZmWRKY40 was induced by drought, high salinity, high temperature, and abscisic acid (ABA). ZmWRKY40 could rapidly respond to drought with peak levels (more than 10-fold) at 1 h after treatment. Overexpression of ZmWRKY40 improved drought tolerance in transgenic Arabidopsis by regulating stress-related genes, and the reactive oxygen species (ROS) content in transgenic lines was reduced by enhancing the activities of peroxide dismutase (POD) and catalase (CAT) under drought stress. According to the results, the present study may provide a candidate gene involved in the drought stress response and a theoretical basis to understand the mechanisms of ZmWRKY40 in response to abiotic stresses in maize. [ABSTRACT FROM AUTHOR]

Background: The calcineurin B-like protein (CBL)-interacting protein kinase (CIPK) signaling pathway responds to various abiotic stresses in plants. Results: Wheat CIPK23, isolated from wheat drought transcriptome data set, was induced by multiple abiotic stresses, including drought, salt, and abscisic acid (ABA). Compared with wild-type plants, TaCIPK23-overexpression wheat and Arabidopsis showed an higher survival rate under drought conditions with enhanced germination rate, developed root system, increased accumulation of osmolytes, and reduced water loss rate. Over-expression of TaCIPK23 rendered transgenic plants ABA sensitivity, as evidenced by delayed seed germination and the induction of stomatal closure. Consistent with the ABA-sensitive phenotype, the expression level of drought- and ABA-responsive genes were increased under drought conditions in the transgenic plants. In addition, using yeast two-hybrid system, pull-down and bimolecular fluorescence complementation (BiFc) assays, TaCIPK23 was found to interact with TaCBL1 on the plasma membrane. Conclusions: These results suggest that TaCIPK23 plays important roles in ABA and drought stress responses, and mediates crosstalk between the ABA signaling pathway and drought stress responses in wheat. [ABSTRACT FROM AUTHOR]

A soybean elongation factor Tu family (EF-Tu) protein, GmEF8, was determined to interact with GmCBL1, and GmEF8 expression was found to be induced by various abiotic stresses such as drought and heat. An ortholog of GmEF8 was identified in Arabidopsis , a T-DNA knockout line for which exhibited hypersensitivity to drought and heat stresses. Complementation with GmEF8 rescued the sensitivity of the Arabidopsis mutant to drought and heat stresses, and GmEF8 overexpression conferred drought and heat tolerance to transgenic Arabidopsis plants. In soybean, plants with GmEF8 -overexpressing hairy roots (OE- GmEF8) exhibited enhanced drought and heat tolerance and had higher proline levels compared to plants with RNAi GmEF8 -knockdown hairy roots (MR- GmEF8) and control hairy roots (EV). A number of drought-responsive genes, such as GmRD22 and GmP5CS , were induced in the OE- GmEF8 line compared to MR- GmEF8 and EV under normal growth conditions. These results suggest that GmEF8 has a positive role in regulating drought and heat stresses in Arabidopsis and soybean. This study reveals a potential role of the soybean GmEF8 gene in response to abiotic stresses, providing a foundation for further investigation into the complexities of stress signal transduction pathways. [ABSTRACT FROM AUTHOR]

Aquaporins (AQPs) constitute a highly diverse family of water channel proteins that play crucial biological functions in plant growth and development and stress physiology. In Arabidopsis , 35 AQPs are classified into four subfamilies (PIPs, TIPs, NIPs and SIPs). However, knowledge about the roles of different subfamily AQPs remains limited. Here, we explored the chromosomal location, gene structure and expression patterns of all AQPs in different tissues or under different abiotic stresses based on available microarray data. Tissue expression analysis showed that different AQPs had various expression patterns in tissues (root, leaf, flower and seed). Expression profiles under stress conditions revealed that most AQPs were responsive to osmotic, salt and drought stresses. Phenotypic and physiological identification showed that Tip2 ; 2 loss-of-function mutant exhibited less sensitive to abiotic stresses (mannitol, NaCl and PEG) compared with wild-type, as evident by analysis of germination rate, root growth, survival rate, ion leakage, malondialdehyde (MDA) and proline contents. Mutant of TIP2 ; 2 modulated the transcript levels of SOS1 , SOS2 , SOS3 , DREB1A , DREB2A and P5CS1 , under abiotic stress conditions. This study provides a basis for further functional identification of stress-related candidate AQPs in Arabidopsis . [ABSTRACT FROM AUTHOR]

Despite their essential and multiple roles in biological processes, the molecular mechanism of Dof transcription factors (TFs) for responding to abiotic stresses is rarely reported in plants. We identified a soybean Dof gene GmDof41 which was involved in the responses to drought, salt, and exogenous ABA stresses. Overexpression of GmDof4 1 in soybean transgenic hairy roots attenuated H 2 O 2 accumulation and regulated proline homeostasis, resulting in the drought and salt tolerance. Yeast one-hybrid and electrophoretic mobility shift assay (EMSA) illustrated that GmDof41 was regulated by the DREB1-type protein GmDREB1B;1 that could improve drought and salt tolerance in plants. Further studies illustrated GmDof41 can directly bind to the promoter of GmDREB2A which encodes a DREB2-type protein and affects abiotic stress tolerance in plants. Collectively, our results suggested that GmDof41 positively regulated drought and salt tolerance by correlating with GmDREB1B;1 and GmDREB2A. This study provides an important basis for further exploring the abiotic stress-tolerance mechanism of Dof TFs in soybean. [ABSTRACT FROM AUTHOR]

Plant non-specific lipid transfer proteins (nsLTPs/LTPs) play important roles in plant growth, development and abiotic stress responses. However, little is known about LTPs in soybean. In this study, 131 LTPs were identified and divided into ten types (I, II, III, IV, V, VI, VII, VIII, IX, and Y), and each GmLtp has the characteristic eight-cysteine motif (8 CM) of plant LTPs. RNA-seq data showed that most GmLtps responded to a variety of abiotic stresses. Among the GmLtp members, GmLtpⅠ.3 was significantly induced under drought and salt treatments. Overexpressing GmLtpⅠ.3 improved tolerance to drought and salt stresses in transgenic Arabidopsis and soybean. The results showed that the accumulation of reactive oxygen species (ROS) in the roots of GmLtpⅠ.3 -overexpressing (OE -GmLtpⅠ.3) plants decreased significantly, compare with GmLtpⅠ.3 RNA interference (RNAi- GmLtpⅠ.3) and empty vector (EV-Control) plants. Furthermore, compared with EV-Control, the expression level of GmSOD1 and GmSOD2 increased in OE- GmLtpI.3. Contrarily, the expression of GmRBOHA and GmRBOHB decreased in OE- GmLtpI.3. The results of this study provide the basis for further comprehensive analyses of LTP genes and insights into abiotic stress response mechanisms in soybean. • 131 plant non-specific lipid transfer proteins genes were identified and analyzed in soybean. • Overexpression of GmLtpⅠ.3 can improve Arabidopsis and soybean stress tolerance. • GmLtpⅠ.3 regulates soybean tolerance to drought and salt stresses at the molecular levels. [ABSTRACT FROM AUTHOR]

Abstract: A novel DREB (dehydration responsive element binding protein) homologous gene, GmDREB2, was isolated from soybean. Based on its similarity with AP2 domains, GmDREB2 was classified into A-5 subgroup in DREB subfamily in AP2/EREBP family. Expression of GmDREB2 gene was induced by drought, high salt, and low temperature stresses and abscisic acid treatment. The GmDREB2 bound specifically to DRE element in vitro. Furthermore, the overexpression of GmDREB2 activated expression of downstream genes in transgenic Arabidopsis, resulting in enhanced tolerance to drought and high-salt stresses and did not cause growth retardation. Analysis of free proline contents in transgenic tobacco indicated that the overexpression of GmDREB2 accumulated higher level of free proline compared to the wild type plants under drought condition. The results from this study indicate that this novel soybean GmDREB2 gene functions as an important transcriptional activator and may be useful in improving of plant tolerance to abiotic stresses in plants. [Copyright &y& Elsevier]