Campus Units

Agronomy, Plant Pathology and Microbiology

Document Type

Article

Publication Version

Published Version

Publication Date

10-2018

Journal or Book Title

Plant Physiology

Volume

178

Issue

2

First Page

907

Last Page

922

DOI

10.1104/pp.18.00903

Abstract

MAPK signaling pathways play critical roles in plant immunity. Here, we silenced multiple genes encoding MAPKs using virus-induced gene silencing mediated by Bean pod mottle virus to identify MAPK genes involved in soybean (Glycine max) immunity. Surprisingly, a strong hypersensitive response (HR) cell death was observed when soybean MAPK KINASE KINASE1 (GmMEKK1), a homolog of Arabidopsis (Arabidopsis thaliana) MEKK1, was silenced. The HR was accompanied by the overaccumulation of defense signaling molecules, salicylic acid (SA) and hydrogen peroxide. Genes involved in primary metabolism, translation/transcription, photosynthesis, and growth/development were down-regulated in GmMEKK1-silenced plants, while the expression of defense-related genes was activated. Accordingly, GmMEKK1-silenced plants were more resistant to downy mildew (Peronospora manshurica) and Soybean mosaic virus compared with control plants. Silencing GmMEKK1 reduced the activation of GmMPK6 but enhanced the activation of GmMPK3 in response to flg22 peptide. Unlike Arabidopsis MPK4, GmMPK4 was not activated by either flg22 or SA. Interestingly, transient overexpression of GmMEKK1 in Nicotiana benthamiana also induced HR. Our results indicate that GmMEKK1 plays both positive and negative roles in immunity and appears to differentially activate downstream MPKs by promoting GmMPK6 activation but suppressing GmMPK3 activation in response to flg22. The involvement of GmMPK4 kinase activity in cell death and in flg22- or SA-triggered defense responses in soybean requires further investigation.

Comments

This article is published as Xu, Hui-Yang, Chi Zhang, Zhen-Chao Li, Zhi-Rong Wang, Xu-Xu Jiang, Ya-Fei Shi, Sheng-Nan Tian et al. "The MAPK kinase kinase GmMEKK1 regulates cell death and defense responses." Plant physiology 178, no. 2 (2018): 907-922. doi:10.1104/pp.18.00903.

Rights

Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.

Language

en

File Format

application/pdf

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