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Article|01 Jun 2021|OPEN
The role of the MAP kinase−kinase protein StMKK1 in potato immunity to different pathogens
Xiaokang Chen1, Wenbin Wang1, Pingping Cai1, Ziwei Wang1, Tingting Li1, & Yu Du1,
1College of Horticulture, Northwest A&F University and Shaanxi Engineering Research Center for Vegetables, Yangling, Shaanxi 712100, China

Horticulture Research 8,
Article number: 117 (2021)
doi: 10.1038/hortres.2021.117
Views: 143

Received: 15 Nov 2020
Revised: 18 Feb 2021
Accepted: 14 Mar 2021
Published online: 01 Jun 2021

Abstract

Mitogen-activated protein kinase (MAPK) cascades play important roles in plant immunity. Previously, we reported that the potato StMKK1 protein negatively regulates Nicotiana benthamiana resistance to Phytophthora infestans. However, the functions of StMKK1 in potato immunity are unknown. To investigate the roles of StMKK1 in potato resistance to different pathogens, such as the potato late-blight pathogen P. infestans, the bacterial wilt pathogen Ralstonia solanacearum, and the gray-mold fungal pathogen Botrytis cinerea, we generated StMKK1 transgenic lines and investigated the response of potato transformants to destructive oomycete, bacterial, and fungal pathogens. The results showed that overexpression and silencing of StMKK1 do not alter plant growth and development. Interestingly, we found that StMKK1 negatively regulated potato resistance to the hemibiotrophic/biotrophic pathogens P. infestans and R. solanacearum, while it positively regulated potato resistance to the necrotrophic pathogen B. cinerea. Further investigation showed that overexpression of StMKK1 suppressed potato pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and salicylic acid (SA)-related responses, while silencing of StMKK1 enhanced PTI and SA-related immune responses. Taken together, our results showed that StMKK1 plays dual roles in potato defense against different plant pathogens via negative regulation of PTI and SA-related signaling pathways.