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Keywords:

  • Bipolaris sorokiniana ;
  • common wheat;
  • drought;
  • MYB transcription factor;
  • resistant response;
  • Triticum aestivum

Summary

  • In this study, we report new insights into the function of a wheat (Triticum aestivum) MYB gene TaPIMP1 through overexpression and underexpression, and its underlying mechanism in wheat.

  • Electrophoretic mobility shift and yeast-one-hybrid assays indicated that TaPIMP1 can bind to five MYB-binding sites including ACI, and activate the expression of the genes with the cis-element, confirming that TaPIMP1 is an MYB transcription activator.

  • TaPIMP1-overexpressing transgenic wheat exhibited significantly enhanced resistance to the fungal pathogen Bipolaris sorokiniana and drought stresses, whereas TaPIMP1-underexpressing transgenic wheat showed more susceptibility to the stresses compared with untransformed wheat, revealing that TaPIMP1 positively modulates host-defense responses to B. sorokiniana and drought stresses. Microarray analysis showed that a subset of defense- and stress-related genes were up-regulated by TaPIMP1. These genes, including TaPIMP1, RD22, TLP4 and PR1a, were regulated by ABA and salicylic acid (SA). TaPIMP1-underexpressing transgenic wheat showed compromised induction of these stress-responsive genes following ABA and SA treatments.

  • In summary, TaPIMP1, as a positive molecular linker, mediates resistance to B. sorokiniana and drought stresses by regulation of stress-related genes in ABA- and SA-signaling pathways in wheat. Furthermore, TaPIMP1 may provide a transgenic tool for engineering multiple-resistance wheat in breeding programs.