A Wheat WRKY Transcription Factor TaWRKY46 Enhances Tolerance to Osmotic Stress in transgenic Arabidopsis Plants

Abstract

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. <i>TaWRKY46</i>, 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 <i>TaWRKY46</i> enhanced osmotic stress tolerance in transgenic <i>Arabidopsis thaliana</i> plants, which was mainly demonstrated by transgenic <i>Arabidopsis</i> 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 (<i>P5CS1</i>, <i>RD29B, DREB2A, ABF3, CBF2,</i> and <i>CBF3</i>) was significantly increased in <i>TaWRKY46-</i>overexpressing transgenic <i>Arabidopsis</i> 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. <i>TaWRKY46</i> 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.