Wheat Heat Shock Factor TaHsfA6f Increases ABA Levels and Enhances Tolerance to Multiple Abiotic Stresses in Transgenic Plants

Huihui Bi,Wenxuan Liu,Huanhuan Li,Yue Zhao

doi:10.3390/ijms21093121

Huihui Bi, Wenxuan Liu + Show 2 more

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https://doi.org/10.3390/ijms21093121

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Abstract

Abiotic stresses are major constraints limiting crop growth and production. Heat shock factors (Hsfs) play significant roles in mediating plant resistance to various environmental stresses, including heat, drought and salinity. In this study, we explored the biological functions and underlying mechanisms of wheat TaHsfA6f in plant tolerance to various abiotic stresses. Gene expression profiles showed that TaHsfA6f has relatively high expression levels in wheat leaves at the reproductive stage. Transcript levels of TaHsfA6f were substantially up-regulated by heat, dehydration, salinity, low temperature, and multiple phytohormones, but was not induced by brassinosteroids (BR). Subcellular localization analyses revealed that TaHsfA6f is localized to the nucleus. Overexpression of the TaHsfA6f gene in Arabidopsis results in improved tolerance to heat, drought and salt stresses, enhanced sensitivity to exogenous abscisic acid (ABA), and increased accumulation of ABA. Furthermore, RNA-sequencing data demonstrated that TaHsfA6f functions through up-regulation of a number of genes involved in ABA metabolism and signaling, and other stress-associated genes. Collectively, these results provide evidence that TaHsfA6f participates in the regulation of multiple abiotic stresses, and that TaHsfA6f could serve as a valuable gene for genetic modification of crop abiotic stress tolerance.

Highlights

Abiotic stresses, such as heat, drought, and salinity, have a tremendous impact on crop growth and production
We found that TaHsfA6f was quickly and dramatically up-regulated by heat stress (Figure 1B) and overexpression of the TaHsfA6f gene improved the heat tolerance of transgenic Arabidopsis (Figure 3C,D)
These results imply that the improvement of heat resistance by TaHsfA6f is conserved between monocot and dicot plant species

Summary

Introduction

Abiotic stresses, such as heat, drought, and salinity, have a tremendous impact on crop growth and production. Plant adaptation to abiotic stresses involves a series of sophisticated regulatory mechanisms. Plant heat shock factors (Hsfs) represent important players in the intricate regulatory network through modulating the expression of genes responsive to a variety of environmental stresses [1]. The protein products of Hsp genes function as molecular chaperones and assist in protein folding, assembly, and translocation, protecting plants from impairment under stress conditions [4]. Hsf gene families have been identified and analyzed at the genome level in many plant species. 21 Hsf genes were identified in Arabidopsis [5], 25 in rice [6], 25 in maize [7], and 38 in soybean [8]

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