RRC ID 59896
Author Nakano M, Mukaihara T.
Title Comprehensive Identification of PTI Suppressors in Type III Effector Repertoire Reveals that Ralstonia solanacearum Activates Jasmonate Signaling at Two Different Steps.
Journal Int J Mol Sci
Abstract Ralstonia solanacearum is the causative agent of bacterial wilt in many plants. To identify R. solanacearum effectors that suppress pattern-triggered immunity (PTI) in plants, we transiently expressed R. solanacearum RS1000 effectors in Nicotiana benthamiana leaves and evaluated their ability to suppress the production of reactive oxygen species (ROS) triggered by flg22. Out of the 61 effectors tested, 11 strongly and five moderately suppressed the flg22-triggered ROS burst. Among them, RipE1 shared homology with the Pseudomonas syringae cysteine protease effector HopX1. By yeast two-hybrid screening, we identified jasmonate-ZIM-domain (JAZ) proteins, which are transcriptional repressors of the jasmonic acid (JA) signaling pathway in plants, as RipE1 interactors. RipE1 promoted the degradation of JAZ repressors and induced the expressions of JA-responsive genes in a cysteine-protease-activity-dependent manner. Simultaneously, RipE1, similarly to the previously identified JA-producing effector RipAL, decreased the expression level of the salicylic acid synthesis gene that is required for the defense responses against R. solanacearum. The undecuple mutant that lacks 11 effectors with a strong PTI suppression activity showed reduced growth of R. solanacearum in Nicotiana plants. These results indicate that R. solanacearum subverts plant PTI responses using multiple effectors and manipulates JA signaling at two different steps to promote infection.
Volume 20(23)
Published 2019-11-28
DOI 10.3390/ijms20235992
PII ijms20235992
PMID 31795135
PMC PMC6928842
MeSH Bacterial Proteins / genetics Bacterial Proteins / metabolism* Cyclopentanes / metabolism* Host-Pathogen Interactions* Oxylipins / metabolism* Plant Immunity* Plant Proteins / genetics Plant Proteins / metabolism Protein Binding Ralstonia solanacearum / genetics Ralstonia solanacearum / pathogenicity* Reactive Oxygen Species / metabolism Signal Transduction Tobacco / genetics Tobacco / immunology Tobacco / microbiology* Transcription Factors / genetics Transcription Factors / metabolism
IF 4.183
Times Cited 2
Arabidopsis / Cultured plant cells, genes pda