Lysin Motif-Containing Proteins LYP4 and LYP6 Play Dual Roles in Peptidoglycan and Chitin Perception in Rice Innate Immunity

• Published in: The Plant cell Vol. 24; no. 8; pp. 3406 - 3419
• Main Authors: Liu, Bing, Li, Jian-Feng, Ao, Ying, Qu, Jinwang, Li, Zhangqun, Su, Jianbin, Zhang, Yang, Liu, Jun, Feng, Dongru, Qi, Kangbiao, He, Yanming, Wang, Jinfa, Wang, Hong-Bin
• Format: Journal Article
• Language: English
• Published: United States American Society of Plant Biologists 01.08.2012
• Subjects: Amino Acid Motifs; Cell Membrane - immunology; Cell Membrane - metabolism; Cell membranes; Chitin; Chitin - immunology; Flagellin - immunology; Flagellin - pharmacology; Gene Expression Regulation, Plant; Genes, Plant; Glucans - metabolism; Innate immunity; Lipopolysaccharides - pharmacology; Magnaporthe - immunology; Magnaporthe - pathogenicity; Oryza - genetics; Oryza - immunology; Oryza - microbiology; Pathogens; Peptidoglycan - immunology; Phylogeny; Plant cells; Plant Diseases - immunology; Plant Diseases - microbiology; Plant Immunity; Plant Proteins - genetics; Plant Proteins - immunology; Plant Proteins - metabolism; Proteins; Protoplasts; Receptors; Receptors, Pattern Recognition - immunology; Receptors, Pattern Recognition - metabolism; Rice; RNA Interference; Transcriptional Activation; Transgenic plants; Xanthomonas - immunology; Xanthomonas - pathogenicity
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.112.102475

Plant innate immunity relies on successful detection of microbe-associated molecular patterns (MAMPs) of invading microbes via pattern recognition receptors (PRRs) at the plant cell surface. Here, we report two homologous rice (Oryza sativa) lysin motif-containing proteins, LYP4 and LYP6, as dual functional PRRs sensing bacterial peptidoglycan (PGN) and fungal chitin. Live cell imaging and microsomal fractionation consistently revealed the plasma membrane localization of these proteins in rice cells. Transcription of these two genes could be induced rapidly upon exposure to bacterial pathogens or diverse MAMPs. Both proteins selectively bound PGN and chitin but not lipopolysaccharide (LPS) in vitro. Accordingly, silencing of either LYP specifically impaired PGN-or chitin-but not LPS-induced defense responses in rice, including reactive oxygen species generation, defense gene activation, and callóse deposition, leading to compromised resistance against bacterial pathogen Xanthomonas oryzae and fungal pathogen Magnaporthe oryzae. Interestingly, pretreatment with excess PGN dramatically attenuated the alkalinization response of rice cells to chitin but not to flagellin; vice versa, pretreatment with chitin attenuated the response to PGN, suggesting that PGN and chitin engage overlapping perception components in rice. Collectively, our data support the notion that LYP4 and LYP6 are promiscuous PRRs for PGN and chitin in rice innate immunity.