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WRKY transcription factors play central roles in developmental processes and stress responses of wheat. Most WRKY proteins of the same group (Group III) have a similar function in abiotic stress responses in plants. TaWRKY46, a member of Group III, was up-regulated by PEG treatment. TaWRKY46-GFP fusion proteins localize to the nucleus in wheat mesophyll protoplasts. Overexpression of TaWRKY46 enhanced osmotic stress tolerance in transgenic Arabidopsis thaliana plants, which was mainly demonstrated by transgenic Arabidopsis plants forming higher germination rate and longer root length on 1/2 Murashige and Skoog (MS) medium containing mannitol. Furthermore, the expression of several stress-related genes (P5CS1, RD29B, DREB2A, ABF3, CBF2, and CBF3) was significantly increased in TaWRKY46-overexpressing transgenic Arabidopsis plants after mannitol treatment. Taken together, these findings proposed that TaWRKY46 possesses vital functions in improving drought tolerance through ABA-dependent and ABA-independent pathways when plants are exposed to adverse osmotic conditions. TaWRKY46 can be taken as a candidate gene for transgenic breeding against osmotic stress in wheat. It can further complement and improve the information of the WRKY family members of Group III. [ABSTRACT FROM AUTHOR]

WRKYs are one of the largest transcription factor (TF) families and play an important role in plant resistance to various stresses. TaWRKY133, a group I WRKY protein, responds to a variety of abiotic stresses, including PEG treatment. The TaWRKY133 protein is located in the nucleus of tobacco epidermal cells, and both its N-terminal and C-terminal domains exhibit transcriptional activation activity. Overexpression of TaWRKY133 reduced drought tolerance in Arabidopsis thaliana, as reflected by a lower germination rate, shorter roots, higher stomatal aperture, poorer growth and lower antioxidant enzyme activities under drought treatment. Moreover, expression levels of stress-related genes (DREB2A, RD29A, RD29B, ABF1, ABA2, ABI1, SOD (Cu/Zn), POD1 and CAT1) were downregulated in transgenic Arabidopsis under drought stress. Gene silencing of TaWRKY133 enhanced the drought tolerance of wheat, as reflected in better growth, higher antioxidant enzyme activities, and higher expression levels of stress-related genes including DREB1, DREB3, ABF, ERF3, SOD (Fe), POD, CAT and P5CS. In conclusion, these results suggest that TaWRKY133 might reduce drought tolerance in plants by regulating the expression of stress-related genes. [ABSTRACT FROM AUTHOR]