GhWRKY40, a multiple stress-responsive cotton WRKY gene, plays an important role in the wounding response and enhances susceptibility to ralstonia solanacearum infection in transgenic Nicotiana benthamiana.

Xiuling Wang,Xingqi Guo,Yuzhen Li,Yan Yan,Xiaoqian Chu,Changai Wu,Sara Amancio

doi:10.1371/journal.pone.0093577

Xiuling Wang, Xingqi Guo + Show 5 more

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https://doi.org/10.1371/journal.pone.0093577

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Journal: PloS one	Publication Date: Apr 18, 2014
Citations: 63	License type: CC BY 4.0

Affiliation: Shandong Agricultural University

Abstract

WRKY transcription factors form one of the largest transcription factor families and function as important components in the complex signaling processes that occur during plant stress responses. However, relative to the research progress in model plants, far less information is available on the function of WRKY proteins in cotton. In the present study, we identified the GhWRKY40 gene in cotton (Gossypium hirsutum) and determined that the GhWRKY40 protein is targeted to the nucleus and is a stress-inducible transcription factor. The GhWRKY40 transcript level was increased upon wounding and infection with the bacterial pathogen Ralstonia solanacearum. The overexpression of GhWRKY40 down-regulated most of the defense-related genes, enhanced the wounding tolerance and increased the susceptibility to R. solanacearum. Consistent with a role in multiple stress responses, we found that the GhWRKY40 transcript level was increased by the stress hormones salicylic acid (SA), methyl jasmonate (MeJA) and ethylene (ET). Moreover, GhWRKY40 interacted with the MAPK kinase GhMPK20, as shown using yeast two-hybrid and bimolecular fluorescence complementation systems. Collectively, these results suggest that GhWRKY40 is regulated by SA, MeJA and ET signaling and coordinates responses to wounding and R. solanacearum attack. These findings highlight the importance of WRKYs in regulating wounding- and pathogen-induced responses.

Highlights

Stress is perceived and transduced through a series of signaling molecules that affect the regulation of stress-inducible genes to initiate the synthesis of different types of proteins, including transcription factors, enzymes, molecular chaperones, ion channels, and transporters, or to alter their activities [1]
WRKY proteins are a class of zinc finger-containing transcription factors (TFs) that are encoded by large gene families in all higher plants and are reported to play a pivotal role in many physiological processes
Our sequence and phylogenetic tree analyses indicated that the GhWRKY40 gene belongs to subgroup IIa (Fig. 1B)

Summary

Introduction

Stress is perceived and transduced through a series of signaling molecules that affect the regulation of stress-inducible genes to initiate the synthesis of different types of proteins, including transcription factors, enzymes, molecular chaperones, ion channels, and transporters, or to alter their activities [1]. Among these proteins, transcription factors (TFs) are crucial in eliciting stress responses by modulating the expression of specific target genes in a temporal and spatial manner; they are necessary for normal development and proper responses to physiological or environmental stimuli [2,3,4,5]. WRKY TFs act as transcriptional regulators by binding to the W-box, which is present in the promoter regions of various stress-related genes, regulating the expression of many genes, resulting in stress tolerance [7]

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