Journal Article

ETHYLENE INSENSITIVE3 and ETHYLENE INSENSITIVE3-LIKE1 Repress SALICYLIC ACID INDUCTION DEFICIENT2 Expression to Negatively Regulate Plant Innate Immunity in Arabidopsis

Lin, Huiqiong, Cui, Haitao, Guo, Hongwei, Zhou, Jian-Min, Xue, Li, Tang, Xiaoyan, Chintamanani, Satya, Germain, Hugo, Zuo, Jianru, Chen, Huamin, Li, Xin, Cai, Run

2009

Overview

Pathogen/microbe-associated molecular patterns (PAMPs/MAMPs) trigger plant immunity that forms the first line inducible defenses in plants. The regulatory mechanism of MAMP-triggered immunity, however, is poorly understood. Here, we show that Arabidopsis thaliana transcription factors ETHYLENE INSENSITIVE3 (EIN3) and ETHYLENE INSENSITIVE3-LIKE1 (EIL1), previously known to mediate ethylene signaling, also negatively regulate PAMP-triggered immunity. Plants lacking EIN3 and EIL1 display enhanced PAMP defenses and heightened resistance to Pseudomonas syringae bacteria. Conversely, plants overaccumulating EIN3 are compromised in PAMP defenses and exhibit enhanced disease susceptibility to Pseudomonas syringae. Microarray analysis revealed that EIN3 and EIL1 negatively control PAMP response genes. Further analyses indicated that SALICYLIC ACID INDUCTION DEFICIENT2 (SID2), which encodes isochorismate synthase required for pathogen-induced biosynthesis of salicylic acid (SA), is a key target of EIN3 and EIL1. Consistent with this, the ein3-1 eil1-1 double mutant constitutively accumulates SA in the absence of pathogen attack, and a mutation in SID2 restores normal susceptibility in the ein3 eil1 double mutant. EIN3 can specifically bind SID2 promoter sequence in vitro and in vivo. Taken together, our data provide evidence that EIN3/EIL1 directly target SID2 to downregulate PAMP defenses.

• Publisher: American Society of Plant Biologists
• Subject: Arabidopsis / Arabidopsis - genetics / Arabidopsis - immunology / Arabidopsis - metabolism / Arabidopsis - microbiology / Arabidopsis Proteins / Arabidopsis Proteins - genetics / Arabidopsis Proteins - metabolism / Arabidopsis Proteins - physiology / Arabidopsis thaliana / Bacteria / Biosynthesis / Chromatin Immunoprecipitation / Disease resistance / DNA / Electrophoretic Mobility Shift Assay / ethylene / Gene expression regulation / Gene Expression Regulation, Plant / Genes / Genetic mutation / genetics / immunity / Immunity, Innate / Immunity, Innate - genetics / Immunity, Innate - physiology / Immunoblotting / immunology / Intramolecular Transferases / Intramolecular Transferases - genetics / Intramolecular Transferases - metabolism / Intramolecular Transferases - physiology / metabolism / microarray technology / microbiology / mutants / mutation / Nuclear Proteins / Nuclear Proteins - genetics / Nuclear Proteins - metabolism / Nuclear Proteins - physiology / Oligonucleotide Array Sequence Analysis / pathogenicity / Pathogens / physiology / Plant cells / Plant immunity / Plants / Plants, Genetically Modified / Plants, Genetically Modified - genetics / Plants, Genetically Modified - immunology / Plants, Genetically Modified - metabolism / Plants, Genetically Modified - microbiology / promoter regions / Promoter Regions, Genetic / Pseudomonas syringae / Pseudomonas syringae - pathogenicity / Reverse Transcriptase Polymerase Chain Reaction / RNA / salicylic acid / transcription factors / Transcription Factors - genetics / Transcription Factors - metabolism / Transcription Factors - physiology