The LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE 1 protein of banana is required for perception of pathogenic and symbiotic signals

• Published in: The New phytologist 2019-08, Vol.223 (3), p.1530-1546
• Main Authors: Zhang, Lu, Yuan, Liangbin, Staehelin, Christian, Li, Yin, Ruan, Jiuxiao, Liang, Zhenwei, Xie, Zhiping, Wang, Wei, Xie, Jianghui, Huang, Shangzhi
• Format: Article
• Language: English
• Subjects: Arabidopsis - metabolism; arbuscular mycorrhiza; Beads; chimeric receptor; Chitin; Chitin - analogs & derivatives; Chitin - metabolism; Complex formation; Coordination compounds; defense; Foc4 (banana wilt); Fungi; Fusarium oxysporum; Gene expression; Gene Expression Regulation, Plant; Gene Silencing; Imaging techniques; Immunoprecipitation; Kinases; Ligands; Localization; Lotus - metabolism; lysin motif receptor kinase; Molecular machines; Musa - genetics; Musa - metabolism; Musa - microbiology; Myc protein; Mycorrhizae - physiology; Nucleic acids; Pathogen-Associated Molecular Pattern Molecules - metabolism; Pathogens; Plant Proteins - chemistry; Plant Proteins - metabolism; Plants (botany); Protein Domains; Receptor mechanisms; Receptors; RNA; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA-mediated interference; Signal Transduction; Signs and symptoms; Symbionts; Symbiosis; Symptoms; Transgenic plants
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.15888

How plants can distinguish pathogenic and symbiotic fungi remains largely unknown. Here, we characterized the role of MaLYK1, a lysin motif receptor kinase of banana. Live cell imaging techniques were used in localization studies. RNA interference (RNAi)-silenced transgenic banana plants were generated to analyze the biological role of MaLYK1. The MaLYK1 ectodomain, chitin beads, chitooligosaccharides (COs) and mycorrhizal lipochitooligosaccharides (Myc-LCOs) were used in pulldown assays. Ligand-induced MaLYK1 complex formation was tested in immunoprecipitation experiments. Chimeric receptors were expressed in Lotus japonicus to characterize the function of the MaLYK1 kinase domain. MaLYK1 was localized to the plasma membrane. MaLYK1 expression was induced by Foc4 (Fusarium oxysporum f. sp. cubense race 4) and diverse microbe-associated molecular patterns. MaLYK1-silenced banana lines showed reduced chitin-triggered defense responses, increased Foc4-induced disease symptoms and reduced mycorrhization. The MaLYK1 ectodomain was pulled down by chitin beads and LCOs or COs impaired this process. Ligand treatments induced MaLYK1 complex formation in planta. The kinase domain of MaLYK1 could functionally replace that of the chitin elicitor receptor kinase 1 (AtCERK1) in Arabidopsis thaliana and of a rhizobial LCO (Nod factor) receptor (LjNFR1) in L. japonicus. MaLYK1 represents a central molecular switch that controls defense- and symbiosis-related signaling.