Characterization of the Wheat Heat Shock Factor TaHsfA2e-5D Conferring Heat and Drought Tolerance in Arabidopsis.

Huihui Bi,Yue Zhao,Xuejun Tian,Wenxuan Liu,Jingnan Miao,Dan Ma,Jiajun Qian,Yan Xu,Jinqiu He,Huanhuan Li,Qifan Chen

doi:10.3390/ijms23052784

Abstract

Environmental stresses, especially heat and drought, severely limit plant growth and negatively affect wheat yield and quality worldwide. Heat shock factors (Hsfs) play a central role in regulating plant responses to various stresses. In this study, the wheat heat shock factor gene TaHsfA2e-5D on chromosome 5D was isolated and functionally characterized, with the goal of investigating its role in responses to heat and drought stresses. Gene expression profiling showed that TaHsfA2e-5D was expressed constitutively in various wheat tissues, most highly in roots at the reproductive stage. The expression of TaHsfA2e-5D was highly up-regulated in wheat seedlings by heat, cold, drought, high salinity, and multiple phytohormones. The TaHsfA2e-5D protein was localized in the nucleus and showed a transcriptional activation activity. Ectopic expression of the TaHsfA2e-5D in yeast exhibited improved thermotolerance. Overexpression of the TaHsfA2e-5D in Arabidopsis results in enhanced tolerance to heat and drought stresses. Furthermore, RT-qPCR analyses revealed that TaHsfA2e-5D functions through increasing the expression of Hsp genes and other stress-related genes, including APX2 and GolS1. Collectively, these results suggest that TaHsfA2e-5D functions as a positive regulator of plants’ responses to heat and drought stresses, which may be of great significance for understanding and improving environmental stress tolerance in crops.

Highlights

Wheat (Triticum aestivum L.) is one of the most important staple food crops in the world
By digging into published transcriptome sequencing data of wheat (TAM107) seedlings under normal growth conditions and heat stress for 6 h [25], we identified a heat shock factor gene, TaHsfA2e-5D, which was highly up-regulated by heat stress and was selected for further functional characterization
High temperatures and drought are increasingly becoming a serious threat to wheat production worldwide

Summary

Introduction

Wheat (Triticum aestivum L.) is one of the most important staple food crops in the world. Environmental stresses, such as high temperatures and drought, adversely affect wheat viability and yield globally, especially during pollination and grain-filling stages. One of the effective strategies is to transcriptionally regulate the expression of stress-related genes, among which transcription factors play a crucial role by activating and/or inhibiting specific genes [3]. Heat shock factors (Hsfs) are one of the prime transcription factors identified in plants in response to heat stress, which are responsible for activation of heat-responsive genes (for example, Hsp genes) by recognizing conserved heat shock elements (HSEs) in their promoters [4,5]. The N-terminal DBD is a typical structure in Hsfs that recognizes HSEs [8].

Methods

Results

Conclusion