Open AccessPotato StMPK7 is a downstream component of StMKK1 and promotes resistance to the oomycete pathogen Phytophthora infestans
Author(s) -
Zhang Houxiao,
Li Fangfang,
Li Zhenzhen,
Cheng Jing,
Chen Xiaokang,
Wang Qinhu,
Joosten Matthieu H.A.J.,
Shan Weixing,
Du Yu
Publication year - 2021
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.13050
Subject(s) - phytophthora infestans , oomycete , biology , nicotiana benthamiana , effector , arabidopsis , microbiology and biotechnology , kinase , arabidopsis thaliana , plant disease resistance , phytophthora , phosphorylation , mutant , pathogen , gene , botany , genetics
A cascade formed by phosphorylation events of mitogen‐activated protein kinases (MAPKs) takes part in plant stress responses. However, the roles of these MAPKs in resistance of potato ( Solanum tuberosum ) against Phytophthora pathogens is not well studied. Our previous work showed that a Phytophthora infestans RXLR effector targets and stabilizes the negative regulator of MAPK kinase 1 of potato (StMKK1). Because in Arabidopsis thaliana the AtMPK4 is the downstream phosphorylation target of AtMKK1, we performed a phylogenetic analysis and found that potato StMPK4/6/7 are closely related and are orthologs of AtMPK4/5/11/12. Overexpression of StMPK4/7 enhances plant resistance to P. infestans and P. parasitica . Yeast two‐hybrid analysis revealed that StMPK7 interacts with StMKK1, and StMPK7 is phosphorylated on flg22 treatment and by expressing constitutively active StMKK1 (CA‐StMKK1), indicating that StMPK7 is a direct downstream signalling partner of StMKK1. Overexpression of StMPK7 in potato enhances potato resistance to P. infestans . Constitutively active StMPK7 (CA‐StMPK7; StMPK7 D198G, E202A ) was found to promote immunity to Phytophthora pathogens and to trigger host cell death when overexpressed in Nicotiana benthamiana leaves. Cell death triggered by CA‐StMPK7 is SGT1/RAR1‐dependent. Furthermore, cell death triggered by CA‐StMPK7 is suppressed on coexpression with the salicylate hydroxylase NahG, and StMPK7 activation promotes salicylic acid (SA)‐responsive gene expression. We conclude that potato StMPK7 is a downstream signalling component of the phosphorelay cascade involving StMKK1 and StMPK7 plays a role in immunity to Phytophthora pathogens via an SA‐dependent signalling pathway.