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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]

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: 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]