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
Date Issued
2014
Date
2014
Author(s)
Chen, Ching-Wei
Abstract
Plasma membrane-localized pattern recognition receptors (PRRs) 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 beta-aminobutyric acid (BABA) revealed IMPAIRED OOMYCETE SUSCEPTIBILITY1 (IOS1) as a critical PTI player. Arabidopsis thaliana ios1 mutants were hyper-susceptible to Pseudomonas syringae bacteria. Accordingly, ios1 mutants demonstrated defective PTI responses, notably delayed up-regulation of PTI-marker genes, lower callose deposition and mitogen-activated protein kinase activities upon bacterial infection or MAMP treatment. Moreover, Arabidopsis lines over-expressing IOS1 were more resistant to P. syringae and demonstrated a primed PTI response. In vitro pull-down, bimolecular fluorescence complementation, co-immunoprecipitation 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 novel regulatory protein of FLS2- and EFR-mediated signaling that primes PTI activation upon bacterial elicitation.
Subjects
β-氨基丁酸
阿拉伯芥
細菌性斑點病原菌
先天性免疫作用
白胺酸重覆受體激酶
減弱卵菌敏感性1
Type
thesis
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