Transcription factor TabHLH49 positively regulates dehydrin WZY2 gene expression and enhances drought stress tolerance in wheat

Hao Liu,Linsheng Zhang,Ying Yang,Xiaoyu Wang,Dandan Liu

doi:10.1186/s12870-020-02474-5

Abstract

BackgroundAs functional proteins, dehydrins are found in many maturing seeds and vegetable tissues under adverse environmental conditions. However, the regulation of dehydrin expression remains unclear.ResultsIn this study, a novel drought stress-related bHLH transcription factor, TabHLH49, was isolated from a wheat cDNA library treated with the drought and cold stress by using yeast one-hybrid system. TabHLH49 protein possesses a typical conserved bHLH domain and is a Myc-type bHLH transcription factor. TabHLH49 was detected in the nucleus of tobacco epidermal cells, and the amino acid sequences at the C-terminus (amino acids 323–362) is necessary for its transactivation activity. Real-time PCR analyses revealed the tissue-specific expression and drought stress-responsive expression of TabHLH49 in wheat. In addition, the verification in Y1H and electrophoretic mobility shift assays illustrated that TabHLH49 protein can bind and interact with the promoter of the wheat WZY2 dehydrin. Furthermore, the dual-luciferase assays showed that TabHLH49 can positively regulate the expression of WZY2 dehydrin. The transient expression and BSMV-mediated gene silencing of TabHLH49 also showed that TabHLH49 positively regulates the expression of WZY2 dehydrin and improves drought stress resistance in wheat.ConclusionsThese results provide direct evidences that TabHLH49 positively regulates expression level of dehydrin WZY2 gene and improves drought tolerance of wheat.

Highlights

As functional proteins, dehydrins are found in many maturing seeds and vegetable tissues under adverse environmental conditions
Characterization of TabHLH49 and bioinformatics analysis In our previous study, we isolated a cDNA segment of bHLH49-like protein interacting with dehydrin WZY2 promoter performed by yeast one-hybrid (Y1H) assay [10], the complete coding sequence was obtained via a BLAST search against the wheat genomic database, and this gene was named TabHLH49
The results indicated that TabHLH49 was highly homologous to AtbHLH049 and was a Myc-type basic helix-loop-helix (bHLH) transcription factor

Summary

Introduction

Dehydrins are found in many maturing seeds and vegetable tissues under adverse environmental conditions. Plants have evolved the ability to synthesize a series of stress-responsive proteins to avoid or defend against adverse conditions. Late embryogenesis abundant (LEA) proteins act as functional proteins in helping to protect cells from direct dehydration. Based on their conserved sequence motifs, the LEA proteins have been grouped into seven distinctive groups [1]. Group 2 LEA proteins, known as dehydrins, are characterized by their highly hydrophilicity. They are considered hydrophiles and contain three typical conserved motifs: K-(EKKGIMDKIKEKLPG), Y-([V/T]D [E/ Q]YGNP) and S-(serine-track) segments.

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