The wheat WRKY transcription factor TaWRKY1-2D confers drought resistance in transgenic Arabidopsis and wheat (Triticum aestivum L.)

The WRKY transcription factor family has been associated with a variety of plant biological processes, such as biotic and abiotic stress responses. In this study, 13 wheat TaWRKY DEGs in transcriptome data before and after drought stress, namely TaWRKY1 to TaWRKY8, including various copies, were identified and classified as Group I, II, or III. TaWRKY1-2D overexpression enhanced drought tolerance in transgenic Arabidopsis. Moreover, the AtRD29A, AtP5CS1, AtPOD1, AtCAT1, and AtSOD (Cu/Zn) genes, which are related to the stress response and antioxidant system, were significantly upregulated in TaWRKY1-2D transgenic Arabidopsis under drought stress. TaWRKY1-2 silencing in wheat increases the MDA content, reduces the contents of proline and chlorophyll and the activities of antioxidant enzymes, and inhibits the expression levels of antioxidant (TaPOD, TaCAT, and TaSOD (Fe))- and stress-related genes (TaP5CS) under drought stress. Yeast two-hybrid screening revealed TaDHN3 as an interaction partner of TaWRKY1-2D; their interaction was further confirmed using yeast twohybrid and bimolecular fluorescence complementation. Furthermore, TaWRKY1-2D may play essential roles in wheat drought tolerance through posttranslational regulation of TaDHN3. Overall, these findings contribute to our knowledge of the WRKY family in wheat and identify TaWRKY1-2D as a promising candidate gene for improving wheat breeding to generate drought-tolerant wheat.

Automated summary

This study identifies 13 wheat TaWRKY DEGs that are associated with drought stress response. Overexpression of TaWRKY1-2D enhances drought tolerance in transgenic Arabidopsis through the upregulation of stress response and antioxidant genes. Silencing of TaWRKY1-2 in wheat leads to increased oxidative damage and decreased antioxidant enzyme activity under drought stress. The interaction between TaWRKY1-2D and TaDHN3 is also identified, suggesting the posttranslational regulation of TaDHN3 by TaWRKY1-2D in wheat drought tolerance. Overall, this study provides insights into the WRKY family in wheat and identifies TaWRKY1-2D as a promising candidate for improving drought tolerance in wheat breeding.