Transcription factor gene TaWRKY76 confers plants improved drought and salt tolerance through modulating stress defensive-associated processes in Triticum aestivum L

Plant Physiol Biochem. 2024 Nov:216:109147. doi: 10.1016/j.plaphy.2024.109147. Epub 2024 Sep 27.

Abstract

WRKY transcription factor (TF) family acts as essential regulators in plant growth and abiotic stress responses. This study reported the function of TaWRKY76, a member of WRKY TF family in Triticum aestivum L., in regulating plant osmotic stress tolerance. TaWRKY76 transcripts were significantly upregulated upon drought and salt signaling, with dose extent- and stress temporal-dependent manners. Plant GUS activity assays suggested that stress responsive cis-acting elements, such as DRE and ABRE, exert essential roles in defining gene transcription under osmotic stress conditions. The TaWRKY76 protein targeted onto nucleus and possessed ability interacting with TaMYC2, a MYC TF member of wheat. TaWRKY76 and TaMYC2 positively regulated plant drought and salt adaptation by modulating osmotic stress-related physiological indices, including osmolyte contents, stomata movement, root morphology, and reactive oxygen species (ROS) homeostasis. Yeast one-hybrid assay indicated the binding ability of TaWRKY76 with promoters of TaDREB1;1, TaNCEB3, and TaCOR15;4. ChIP-PCR analysis confirmed that the osmotic stress genes are transcriptionally regulated by TaWRKY76. Moreover, the transgenic lines with knockdown of these stress-response genes displayed lowered plant biomass together with worsened root growth traits, decreased proline contents, and elevated ROS amounts. These results suggested that these stress defensive genes contributed to TaWRKY76-modulated osmotic stress tolerance. Highly positive correlations were observed between yield and the transcripts of TaWRKY76 in a wheat variety panel under field drought condition. A major haplotype TaWRKY76 Hap1 conferred improved drought tolerance. Our results suggested that TaWRKY76 is essential in plant drought and salt adaptation and a valuable target for molecular breeding stress-tolerant cultivars in Triticum aestivum L..

Keywords: Gene expression; Osmotic stress; Physiological indices; Transgene analysis; Wheat WRKY76.

MeSH terms

  • Droughts*
  • Gene Expression Regulation, Plant*
  • Osmotic Pressure
  • Plant Proteins* / genetics
  • Plant Proteins* / metabolism
  • Plants, Genetically Modified
  • Reactive Oxygen Species / metabolism
  • Salt Tolerance* / genetics
  • Stress, Physiological / genetics
  • Transcription Factors* / genetics
  • Transcription Factors* / metabolism
  • Triticum* / genetics
  • Triticum* / metabolism
  • Triticum* / physiology

Substances

  • Plant Proteins
  • Transcription Factors
  • Reactive Oxygen Species