The Arabidopsis malectin-like leucine-rich repeat receptor-like kinase IOS1 associates with the pattern recognition receptors FLS2 and EFR and is critical for priming of pattern-triggered immunity.

Abstract

Plasma membrane-localized pattern recognition receptors such as FLAGELLIN SENSING2 (FLS2) and EF-TU RECEPTOR (EFR) recognize microbe-associated molecular patterns (MAMPs) to activate the first layer of plant immunity termed pattern-triggered immunity (PTI). A reverse genetics approach with genes responsive to the priming agent β-aminobutyric acid (BABA) revealed IMPAIRED OOMYCETE SUSCEPTIBILITY1 (IOS1) as a critical PTI player. Arabidopsis thaliana ios1 mutants were hypersusceptible to Pseudomonas syringae bacteria. Accordingly, ios1 mutants demonstrated defective PTI responses, notably delayed upregulation of PTI marker genes, lower callose deposition, and mitogen-activated protein kinase activities upon bacterial infection or MAMP treatment. Moreover, Arabidopsis lines overexpressing IOS1 were more resistant to P. syringae and demonstrated a primed PTI response. In vitro pull-down, bimolecular fluorescence complementation, coimmunoprecipitation, and mass spectrometry analyses supported the existence of complexes between the membrane-localized IOS1 and FLS2 and EFR. IOS1 also associated with BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1) in a ligand-independent manner and positively regulated FLS2/BAK1 complex formation upon MAMP treatment. Finally, ios1 mutants were defective in BABA-induced resistance and priming. This work reveals IOS1 as a regulatory protein of FLS2- and EFR-mediated signaling that primes PTI activation upon bacterial elicitation.

• Authors: Ching-Wei Chen, Dario Panzeri, Yu-Hung Yeh, Yasuhiro Kadota, Pin-Yao Huang, Chia-Nan Tao, Milena Roux, Shiao-Chiao Chien, Tzu-Chuan Chin, Po-Wei Chu, Cyril Zipfel, Laurent Zimmerli
• Journal: The Plant cell (Plant Cell) Vol. 26 Issue 7 Pg. 3201-19 (Jul 2014) ISSN: 1532-298X [Electronic] England
• PMID: 25070640 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Retracted Publication)
• Copyright: © 2014 American Society of Plant Biologists. All rights reserved.

Chemical References

• Aminobutyrates
• Arabidopsis Proteins
• EFR protein, Arabidopsis
• Receptors, Pattern Recognition
• 3-aminobutyric acid
• At1g51800 protein, Arabidopsis
• Protein Kinases
• FLS2 protein, Arabidopsis
• Leucine

Topics

• Aminobutyrates (metabolism)
• Arabidopsis (enzymology, genetics, immunology)
• Arabidopsis Proteins (genetics, metabolism)
• Gene Expression
• Gene Expression Regulation, Plant
• Leucine (metabolism)
• Mutation
• Plant Diseases (immunology, microbiology)
• Plant Immunity
• Protein Kinases (genetics, metabolism)
• Pseudomonas syringae (physiology)
• Receptors, Pattern Recognition (genetics, metabolism)
• Signal Transduction