SaHsfA4c From Sedum alfredii Hance Enhances Cadmium Tolerance by Regulating ROS-Scavenger Activities and Heat Shock Proteins Expression.

Shuangshuang Chen,He Li,Ying Wang,Renying Zhuo,Zhuchou Lu,Xiaojiao Han,Longhua Wu,Miao Yu,Guirong Qiao,Mingying Liu,Yunxing Zhang

doi:10.3389/fpls.2020.00142

Abstract

The heat shock transcription factor (Hsf) family, an important member in plant stress response, affects cadmium (Cd) tolerance in plants. In this study, we identified and functionally characterized a transcript of the Hsf A4 subgroup from Sedum alfredii. Designated as SaHsfA4c, the open reading frame was 1,302 bp long and encoded a putative protein of 433 amino acids containing a complete DNA-binding domain (DBD). Heterologous expression of SaHsfA4c in yeast enhanced Cd stress tolerance and accumulation, whereas expression of the alternatively spliced transcript InSaHsfA4c which contained an intron and harbored an incomplete DBD, resulted in relatively poor Cd stress tolerance and low Cd accumulation in transgenic yeast. The function of SaHsfA4c under Cd stress was characterized in transgenic Arabidopsis and non-hyperaccumulation ecotype S. alfredii. SaHsfA4c was able to rescue the Cd sensitivity of the Arabidopsis athsfa4c mutant. SaHsfA4c reduced reactive oxygen species (ROS) accumulation and increased the expression of ROS-scavenging enzyme genes and Hsps in transgenic lines. The present results suggest that SaHsfA4c increases plant resistance to stress by up-regulating the activities of ROS-scavenging enzyme and the expression of Hsps.

Highlights

Heavy metal pollution from industrial and agricultural activities has become a worldwide concern (Akesson et al, 2014)
The results showed that SaHsfA4c plays a role in Cd tolerance
SaHsfA4c was upregulated under Cd stress, with higher transcript levels detected in the root, stem, and leaf (Figure 2)

Summary

Introduction

Heavy metal pollution from industrial and agricultural activities has become a worldwide concern (Akesson et al, 2014). Many genes associated with Cd uptake, resistance and hyperaccumulation, such as SpHMA3, SpMTL, SaREF, SaMT2, SaCAX2 and SaCu/ZnSOD, have been characterized from S. plumbizincicola and S. alfredii (Zhang et al, 2014; Liu et al, 2016; Zhang et al, 2016; Li et al, 2017; Liu et al, 2017; Peng et al, 2017). Despite these findings, transcription factors, which play an important role in abiotic stress, remain largely unknown in S. alfredii

Methods

Results

Conclusion