Enhanced drought tolerance in transgenic Arabidopsis thaliana through overexpression of a novel WRKY transcription factor gene, TaWRKY31

Abstract

Abstract Background Wheat, a crucial food crop in China, is highly vulnerable to drought stress throughout its growth and development. WRKY transcription factors (TFs), being one of the largest families of TFs, play a vital role in responding to various abiotic stresses. Results In this study, we cloned and characterized the TF TaWRKY31 from wheat. This TF, belonging to the WRKY II family, contains a WRKYGQK amino acid sequence and a C2H2-type zinc finger structure. TaWRKY31 is expressed with tissue specificity and is responsive to abiotic stresses in wheat. TaWRKY31 protein is localized in the nucleus and can function as a TF with transcription activating activity at the N-terminus. Results showed that the wheat plants with silenced strains (BSMV: TaWRKY31-1as and BSMV: TaWRKY31-2as) exhibited poor growth status and low relative water content when subjected to drought treatment. Moreover, the levels of O2·−, H2O2, and malondialdehyde (MDA) in the plants increased, while the activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) decreased. The expression levels of TaSOD(Fe), TaPOD, TaCAT, TaDREB1, TaP5CS, TaNCED1, TaSnRK2, TaPP2C, and TaPYL5 all decreased. The heterologous overexpression of TaWRKY31 in Arabidopsis decreased H2O2 and MDA content, stomatal opening, and water loss. Furthermore, an increase in resistance oxidase activity, germination rate, and root length in the TaWRKY31 transgenic Arabidopsis was observed. Lastly, the expression levels of AtNCED3, AtABA2, AtSnRK2.2, AtABI1, AtABF3, AtP5CS1, AtSOD(Cu/Zn), AtPOD, AtCAT, AtRD29A, AtRD29B, and AtDREB2A increased in the transgenic plants. Conclusions Our findings indicate that TaWRKY31 enhances drought resistance in plants by promoting the scavenging of reactive oxygen species, reducing stomatal opening, and increasing the expression levels of stress-related genes.