Overexpression of TaSIM provides increased drought stress tolerance in transgenic Arabidopsis.

Abstract Drought is the most serious meteorological disaster affecting wheat production. Members of the R2R3-MYB gene subfamily play a crucial role in the regulation of the wheat drought stress response. In this study, the function of polyethylene glycol (PEG)-induced expression of the wheat R2R3-MYB gene TaSIM in response to drought stress was characterized. β-Glucuronidase (GUS) histochemical staining revealed that the TaSIM promoter can drive the expression of the GUS gene in the flowers, roots, stems and rosette leaves. Moreover, TaSIM was expressed in the stamens, pistils, roots, stems and leaves of wheat. The TaSIM promoter contains a known stress-responsive cis -acting element and is inducible by stress, PEG and abscisic acid (ABA). Under drought stress, compared with wild-type (WT) Arabidopsis , transgenic Arabidopsis overexpressing TaSIM presented significantly lower leaf water loss rates and increased survival. Moreover, the content of soluble sugars and proline and the expression of stress-related genes (RD29A and RD22) in transgenic Arabidopsis overexpressing TaSIM were higher than those in WT Arabidopsis under drought stress. Our results indicate that TaSIM plays a positive role in the drought stress response and can be used as a candidate gene for the genetic engineering of wheat drought resistance. Highlights • TaSIM is expressed in the stamens, pistils, roots, stems and leaves of wheat. • ABRE and CRT/DRE cis -acting elements are present in the TaSIM promoter, which is induced by stress, PEG and ABA. • Transgenic Arabidopsis overexpressing TaSIM has a low water loss rate, accumulates relatively high contents of soluble sugars and proline, and expresses RD22 and RD29A , thereby enhancing Arabidopsis tolerance to drought stress. [ABSTRACT FROM AUTHOR]