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Summary: Abscisic acid (ABA) receptors are considered as the targeted manipulation of ABA sensitivity and water productivity in plants. Regulation of their stability or activity will directly affect ABA signalling. Mitogen‐activated protein kinase (MAPK) cascades link multiple environmental and plant developmental cues. However, the molecular mechanism of ABA signalling and MAPK cascade interaction remains largely elusive.TaMPK3 overexpression decreases drought tolerance and wheat sensitivity to ABA, significantly weakening ABA's inhibitory effects on growth. Under drought stress, overexpression lines show lower survival rates, shoot fresh weight and proline content, but higher malondialdehyde levels at seedling stage, as well as decreased grain width and 1000 grain weight in both glasshouse and field conditions at the adult stage. TaMPK3‐RNAi increases drought tolerance.TaMPK3 interaction with TaPYL4 leads to decreased TaPYL4 levels by promoting its ubiquitin‐mediated degradation, whereas ABA treatment diminishes TaMPK3–TaPYL interactions. In addition, the expression of ABA signalling proteins is impaired in TaMPK3‐overexpressing wheat plants under ABA treatment. The MPK3‐PYL interaction module was found to be conserved across monocots and dicots.Our results suggest that the MPK3‐PYL module could serve as a negative regulatory mechanism for balancing appropriate drought stress response with normal plant growth signalling in wheat. [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]

Summary: Drought and salt stresses impose major constraints on soybean production worldwide. However, improving agronomically valuable soybean traits under drought conditions can be challenging due to trait complexity and multiple factors that influence yield. Here, we identified a nuclear factor Y C subunit (NF‐YC) family transcription factor member, GmNF‐YC14, which formed a heterotrimer with GmNF‐YA16 and GmNF‐YB2 to activate the GmPYR1‐mediated abscisic acid (ABA) signalling pathway to regulate stress tolerance in soybean. Notably, we found that CRISPR/Cas9‐generated GmNF‐YC14 knockout mutants were more sensitive to drought than wild‐type soybean plants. Furthermore, field trials showed that overexpression of GmNF‐YC14 or GmPYR1 could increase yield per plant, grain plumpness, and stem base circumference, thus indicating improved adaptation of soybean plants to drought conditions. Taken together, our findings expand the known functional scope of the NF‐Y transcription factor functions and raise important questions about the integration of ABA signalling pathways in plants. Moreover, GmNF‐YC14 and GmPYR1 have potential for application in the improvement of drought tolerance in soybean plants. [ABSTRACT FROM AUTHOR]

Abiotic stresses, such as drought and salinity, severely affects the growth, development and productivity of the plants. The Catharanthus roseus RLK1-like (CrRLK1L) protein kinase family is involved in several processes in the plant life cycle. However, there have been few studies addressing the functions of CrRLK1L proteins in soybean. In this study, 38 CrRLK1L genes were identified in the soybean genome (Glycine max Wm82.a2.v1). Phylogenetic analysis demonstrated that soybean CrRLK1L genes were grouped into clusters, cluster I, II, III. The chromosomal mapping demonstrated that 38 CrRLK1L genes were located in 14 of 20 soybean chromosomes. None were discovered on chromosomes 1, 4, 6, 7, 11, and 14. Gene structure analysis indicated that 73.6% soybean CrRLK1L genes were characterized by a lack of introns.15.7% soybean CrRLK1L genes only had one intron and 10.5% soybean CrRLK1L genes had more than one intron. Five genes were obtained from soybean drought- and salt-induced transcriptome databases and were found to be highly up-regulated. GmCrRLK1L20 was notably up-regulated under drought and salinity stresses, and was therefore studied further. Subcellular localization analysis revealed that the GmCrRLK1L20 protein was located in the cell membrane. The overexpression of the GmCrRLK1L20 gene in soybean hairy roots improved both drought tolerance and salt stresses and enhanced the expression of the stress-responsive genes GmMYB84 , GmWRKY40 , GmDREB-like , GmGST15 , GmNAC29 , and GmbZIP78. These results indicated that GmCrRLK1L20 could play a vital role in defending against drought and salinity stresses 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]

NF-YA transcription factors function in modulating tolerance to abiotic stresses that are serious threats to crop yields. In this study, GmNFYA13 , an NF-YA gene in soybean, was strongly induced by salt, drought, ABA, and H2O2, and suppressed by tungstate, an ABA synthesis inhibitor. The GmNFYA13 transcripts were detected in different tissues in seedling and flowering stages, and the expression levels in roots were highest. GmNFYA13 is a nuclear localization protein with self-activating activity. Transgenic Arabidopsis plants overexpressing GmNFYA13 with higher transcript levels of stress-related genes showed ABA hypersensitivity and enhanced tolerance to salt and drought stresses compared with WT plants. Moreover, overexpression of GmNFYA13 resulted in higher salt and drought tolerance in OE soybean plants, while suppressing it produced the opposite results. In addition, GmNFYA13 could bind to the promoters of GmSALT3 , GmMYB84 , GmNCED3 , and GmRbohB to regulate their expression abundance in vivo. The data in this study suggested that GmNFYA13 enhanced salt and drought tolerance in soybean plants. [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]

Plant calcium-dependent protein kinases (CDPKs) were reported to play important roles in plant resistance to abiotic stress. Foxtail millet cultivation “H138” was used for RNA-seq analysis. The data from drought-induced de novo transcriptomic sequences of foxtail millet showed that CDPKs were up- or down-regulated by drought to different degrees. In this study, 29 foxtail millet CDPKs were classified into four subgroups. These genes were unevenly distributed on nine foxtail millet chromosomes, and chromosomes 2, 3, and 9 contained the most SiCDPK members. Analysis of putative cis-acting elements showed that most foxtail millet CDPK genes contained the ABRE, LTR, HSE, MYB, MYC, DRE, CGTCA-motif, and TGACG-motif cis-acting elements, which could be activated by abiotic stresses. Real-time PCR analysis indicated that 29 SiCDPK genes experienced different degrees of induction under drought and ABA stresses. SiCDPK24 had the highest expression levels at 6 and 12 h of drought treatment and was chosen for further analysis. SiCDPK24 localized to the cell membrane and the nucleus of Arabidopsis mesophyll protoplasts. Western blot analysis showed that SiCDPK24 protein had autophosphorylation activity. Overexpression of SiCDPK24 in Arabidopsis enhanced drought resistance and improved the survival rate under drought stress. It also activated the expressions of nine stress-related genes, namely RD29A, RD29B, RD22, KIN1, COR15, COR47, LEA14, CBF3/DREB1A, and DREB2A. These genes are involved in resistance to abiotic stresses in Arabidopsis. These results indicate that foxtail millet CDPK genes play important roles in resisting drought stress. [ABSTRACT FROM AUTHOR]

YABBY family is a plant specific transcription factor family, with the typical N-terminal C2C2 type zinc finger domain and the C-terminal YABBY conservative structure domain, which plays important biological roles in plant growth, development and morphogenesis. In this study, a total of 17 YABBY genes were identified in the soybean genome. The results of this research showed that 17 soybean YABBY genes were located on 11 chromosomes. Analysis of putative cis -acting elements showed that soybean YABBY genes contained lots of MYB and MYC elements. Quantitative Real-time PCR (qRT-PCR) showed that the expressions of GmYABBY3 , GmYABBY10 and GmYABBY16 were more highly sensitive in drought, NaCl and ABA stresses. And the transient expression in Arabidopsis protoplasts showed that GmYABBY3 protein distributed uniformly the whole cells, while GmYABBY10 protein was mainly localized in the membranes and cytoplasm and GmYABBY16 protein was localized the nucleus and membranes. To further identify the function of GmYABBY10 , we obtained the transgenic Arabidopsis overexpression GmYABBY10 . Based on germination and seedling root arrays in transgenic Arabidopsis , we found that the rates of wild type seeds was a litter higher than that of GmYABBY10 transgenic seeds under both PEG and NaCl treatment. While the root length and root surface of wild type seedlings were bigger than those of GmYABBY10 transgenic seedlings. When seedlings were grown in soil, the survival rates of wild type were higher than those of transgenic plants under both PEG and NaCl treatment, which indicated that GmYABBY10 may be a negatively regulator in plant resistances to drought and salt stresses. This study provided valuable information regarding the classification and functions of YABBY genes in soybean. [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]