TaWRKY24-1D, interacts with TaERFL1a, regulates DHAR-mediated ASA-GSH biosynthesis to enhance drought tolerance in wheat

Drought is a major environmental factor limiting wheat yield and quality. WRKY transcription factors play crucial roles in abiotic stresses, including drought stress. In this study, we found that the WRKY transcription factors TaWRKY24 interacted with TaERFL1a in the response to wheat drought stress as determined using yeast two-hybrid and bimolecular fluorescence complementation. Transiently silencing of TaWRKY24 in wheat increased sensitivity to drought stress by increasing the malondialdehyde and hydrogen peroxide contents, decreasing the activities of ascorbate peroxidase, superoxide dismutase, or catalase, contents of ascorbate (ASA), and glutathione (GSH), and inhibiting the biomass and relative water content. Moreover, qPCR analyses showed that the expression levels of ASA-GSH-related genes were also significantly inhibited in TaWRKY24-silenced wheat plants. Dehydroascorbate reductase (DHAR) were the lowest expression levels than other ASA-GSH-related genes, indicating that this gene may be mainly regulated by TaWRKY24. In addition, yeast one-hybrid, luciferase complementation imaging, and luciferase assays revealed greater DHAR promoter binding activity for TaWRKY24 than TaERFL1a, suggesting that TaWRKY24 positively regulates the expression levels of DHAR and interactes with TaERFL1a to promote wheat drought tolerance. Therefore, these results provide insight into the molecular regulatory mechanisms by which TaWRKY24 contributes to wheat drought resistance, and reveals the candidate genes for breeding the drought-resistance wheat varieties.