Lysin motif (LysM) receptor kinase that functions as a cell surface receptor in chitin elicitor (chitooligosaccharides) signaling leading to innate immunity. Recognizes microbe-derived N-acetylglucosamine (NAG)-containing ligands. Involved in the resistance to the pathogenic fungus Alternaria brassicicola and to the bacterial pathogen the bacterial pathogen Pseudomonas syringae pv tomato DC3000, probably by sensing microbe-associated molecular pattern (MAMP) and pathogen-associated molecular patterns (PAMP). May play a role in detecting peptidoglycans (e.g. PGNs) during bacterial growth