The Arabidopsis malectin-like/LRR-RLK IOS1 is critical for BAK1-dependent and BAK1-ndependent pattern-triggered immunity

Yeh, Yu-Hung, Panzeri, Dario, Kadota, Yasuhiro, Huang, Yi-Chun, Huang, Pin-Yao, Tao, Chia-Nan, Roux, Milena, Chien, Hsiao-Chiao, Chin, Tzu-Chuan, Chu, Po-Wei, Zipfel, Cyril and Zimmerli, Laurent (2016) The Arabidopsis malectin-like/LRR-RLK IOS1 is critical for BAK1-dependent and BAK1-ndependent pattern-triggered immunity. The Plant Cell, 28 (7). pp. 1701-1721. ISSN 1040-4651

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Plasma membrane-localized pattern recognition receptors (PRRs) such as FLAGELLIN SENSING2 (FLS2), EF-TU RECEPTOR (EFR) and CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) recognize microbe-associated molecular patterns (MAMPs) to activate pattern-triggered immunity (PTI). A reverse genetics approach on 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 showed defective PTI responses, notably delayed up-regulation of the PTI-marker gene FLG22-INDUCED RECEPTOR-LIKE KINASE1 (FRK1), reduced callose deposition and mitogen-activated protein kinase activation upon MAMP treatment. Moreover, Arabidopsis lines over-expressing IOS1 were more resistant to bacteria and showed 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 BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1)-dependent PRRs FLS2 and EFR, as well as with the BAK1-independent PRR CERK1. IOS1 also associated with BAK1 in a ligand-independent manner, and positively regulated FLS2-BAK1 complex formation upon MAMP treatment. In addition, IOS1 was critical for chitin-mediated PTI. Finally, ios1 mutants were defective in BABA-induced resistance and priming. This work reveals IOS1 as a novel regulatory protein of FLS2-, EFR- and CERK1-mediated signaling pathways that primes PTI activation.

Item Type: Article
Faculty \ School: Faculty of Science > School of Biological Sciences
UEA Research Groups: Faculty of Science > Research Groups > Plant Sciences
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Depositing User: Pure Connector
Date Deposited: 16 Jun 2016 15:00
Last Modified: 22 Oct 2022 01:16
DOI: 10.1105/tpc.16.00313


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