Cargando…

CaWRKY40b in Pepper Acts as a Negative Regulator in Response to Ralstonia solanacearum by Directly Modulating Defense Genes Including CaWRKY40

WRKY transcription factors (TFs) have been implicated in plant growth, development, and in response to environmental cues; however, the function of the majority of pepper WRKY TFs remains unclear. In the present study, we functionally characterized CaWRKY40b, a homolog of AtWRKY40, in pepper immunit...

Descripción completa

Detalles Bibliográficos
Autores principales: Ifnan Khan, Muhammad, Zhang, Yangwen, Liu, Zhiqin, Hu, Jiong, Liu, Cailing, Yang, Sheng, Hussain, Ansar, Furqan Ashraf, Muhammad, Noman, Ali, Shen, Lei, Xia, Xiaoqin, Yang, Feng, Guan, Deyi, He, Shuilin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5983674/
https://www.ncbi.nlm.nih.gov/pubmed/29738468
http://dx.doi.org/10.3390/ijms19051403
_version_ 1783328472737775616
author Ifnan Khan, Muhammad
Zhang, Yangwen
Liu, Zhiqin
Hu, Jiong
Liu, Cailing
Yang, Sheng
Hussain, Ansar
Furqan Ashraf, Muhammad
Noman, Ali
Shen, Lei
Xia, Xiaoqin
Yang, Feng
Guan, Deyi
He, Shuilin
author_facet Ifnan Khan, Muhammad
Zhang, Yangwen
Liu, Zhiqin
Hu, Jiong
Liu, Cailing
Yang, Sheng
Hussain, Ansar
Furqan Ashraf, Muhammad
Noman, Ali
Shen, Lei
Xia, Xiaoqin
Yang, Feng
Guan, Deyi
He, Shuilin
author_sort Ifnan Khan, Muhammad
collection PubMed
description WRKY transcription factors (TFs) have been implicated in plant growth, development, and in response to environmental cues; however, the function of the majority of pepper WRKY TFs remains unclear. In the present study, we functionally characterized CaWRKY40b, a homolog of AtWRKY40, in pepper immunity. Ralstonia solanacearum inoculation (RSI) in pepper plants resulted in downregulation of CaWRKY40b transcript, and green fluorescent protein (GFP)-tagged CaWRKY40b was localized to the nuclei when transiently overexpressed in the leaves of Nicotiana benthamiana. Virus-induced gene silencing (VIGS) of CaWRKY40b significantly decreased pepper’ susceptibility to RSI. Consistently, the transient over-expression of CaWRKY40b-SRDX (chimeric repressor version of CaWRKY40b) triggered cell death, as indicated by darker trypan blue and DAB staining. CaWRKY40b targets a number of immunity-associated genes, including CaWRKY40 JAR, RLK1, EIN3, FLS2, CNGIC8, CDPK13, and heat shock cognate protein 70 (HSC70), which were identified by ChIP-seq and confirmed using ChIP-real time PCR. Among these target genes, the negative regulator HSC70 was upregulated by transient overexpression of CaWRKY40b and downregulated by silencing of CaWRKY40b, whereas other positive regulators as well as two non-target genes, CaNPR1 and CaDEF1, were downregulated by the transient overexpression of CaWRKY40b and upregulated by CaWRKY40b silencing or transient overexpression of CaWRKY40b-SRDX. In addition, CaWRKY40b exhibited a positive feedback regulation at transcriptional level by directly targeting the promoter of itself. In conclusion, the findings of the present study suggest that CaWRKY40b acts as a negative regulator in pepper immunity against R. solanacearum by transcriptional modulation of a subset of immunity-associated genes; it also represses immunity in the absence of a pathogen, and derepresses immunity upon pathogen challenge.
format Online
Article
Text
id pubmed-5983674
institution National Center for Biotechnology Information
language English
publishDate 2018
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-59836742018-06-05 CaWRKY40b in Pepper Acts as a Negative Regulator in Response to Ralstonia solanacearum by Directly Modulating Defense Genes Including CaWRKY40 Ifnan Khan, Muhammad Zhang, Yangwen Liu, Zhiqin Hu, Jiong Liu, Cailing Yang, Sheng Hussain, Ansar Furqan Ashraf, Muhammad Noman, Ali Shen, Lei Xia, Xiaoqin Yang, Feng Guan, Deyi He, Shuilin Int J Mol Sci Article WRKY transcription factors (TFs) have been implicated in plant growth, development, and in response to environmental cues; however, the function of the majority of pepper WRKY TFs remains unclear. In the present study, we functionally characterized CaWRKY40b, a homolog of AtWRKY40, in pepper immunity. Ralstonia solanacearum inoculation (RSI) in pepper plants resulted in downregulation of CaWRKY40b transcript, and green fluorescent protein (GFP)-tagged CaWRKY40b was localized to the nuclei when transiently overexpressed in the leaves of Nicotiana benthamiana. Virus-induced gene silencing (VIGS) of CaWRKY40b significantly decreased pepper’ susceptibility to RSI. Consistently, the transient over-expression of CaWRKY40b-SRDX (chimeric repressor version of CaWRKY40b) triggered cell death, as indicated by darker trypan blue and DAB staining. CaWRKY40b targets a number of immunity-associated genes, including CaWRKY40 JAR, RLK1, EIN3, FLS2, CNGIC8, CDPK13, and heat shock cognate protein 70 (HSC70), which were identified by ChIP-seq and confirmed using ChIP-real time PCR. Among these target genes, the negative regulator HSC70 was upregulated by transient overexpression of CaWRKY40b and downregulated by silencing of CaWRKY40b, whereas other positive regulators as well as two non-target genes, CaNPR1 and CaDEF1, were downregulated by the transient overexpression of CaWRKY40b and upregulated by CaWRKY40b silencing or transient overexpression of CaWRKY40b-SRDX. In addition, CaWRKY40b exhibited a positive feedback regulation at transcriptional level by directly targeting the promoter of itself. In conclusion, the findings of the present study suggest that CaWRKY40b acts as a negative regulator in pepper immunity against R. solanacearum by transcriptional modulation of a subset of immunity-associated genes; it also represses immunity in the absence of a pathogen, and derepresses immunity upon pathogen challenge. MDPI 2018-05-08 /pmc/articles/PMC5983674/ /pubmed/29738468 http://dx.doi.org/10.3390/ijms19051403 Text en © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Ifnan Khan, Muhammad
Zhang, Yangwen
Liu, Zhiqin
Hu, Jiong
Liu, Cailing
Yang, Sheng
Hussain, Ansar
Furqan Ashraf, Muhammad
Noman, Ali
Shen, Lei
Xia, Xiaoqin
Yang, Feng
Guan, Deyi
He, Shuilin
CaWRKY40b in Pepper Acts as a Negative Regulator in Response to Ralstonia solanacearum by Directly Modulating Defense Genes Including CaWRKY40
title CaWRKY40b in Pepper Acts as a Negative Regulator in Response to Ralstonia solanacearum by Directly Modulating Defense Genes Including CaWRKY40
title_full CaWRKY40b in Pepper Acts as a Negative Regulator in Response to Ralstonia solanacearum by Directly Modulating Defense Genes Including CaWRKY40
title_fullStr CaWRKY40b in Pepper Acts as a Negative Regulator in Response to Ralstonia solanacearum by Directly Modulating Defense Genes Including CaWRKY40
title_full_unstemmed CaWRKY40b in Pepper Acts as a Negative Regulator in Response to Ralstonia solanacearum by Directly Modulating Defense Genes Including CaWRKY40
title_short CaWRKY40b in Pepper Acts as a Negative Regulator in Response to Ralstonia solanacearum by Directly Modulating Defense Genes Including CaWRKY40
title_sort cawrky40b in pepper acts as a negative regulator in response to ralstonia solanacearum by directly modulating defense genes including cawrky40
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5983674/
https://www.ncbi.nlm.nih.gov/pubmed/29738468
http://dx.doi.org/10.3390/ijms19051403
work_keys_str_mv AT ifnankhanmuhammad cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT zhangyangwen cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT liuzhiqin cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT hujiong cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT liucailing cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT yangsheng cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT hussainansar cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT furqanashrafmuhammad cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT nomanali cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT shenlei cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT xiaxiaoqin cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT yangfeng cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT guandeyi cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40
AT heshuilin cawrky40binpepperactsasanegativeregulatorinresponsetoralstoniasolanacearumbydirectlymodulatingdefensegenesincludingcawrky40