Plant pattern-recognition receptors controlling innate immunity

Plants are exposed to numerous potential pathogenic microbes. To counter the threat, plants have evolved diverse pattern- recognition receptors (PRRs), which are receptor kinases (RKs) and receptor proteins (RPs) specialized to detect conserved pathogen/microbe-associated molecular patterns (PAMPs/MAMPs). Although only a handful of RKs and RPs are known PRRs, they belong to the receptor-like kinase (RLK) and receptor-like protein (RLP) superfamilies that undergo lineage-specific expansion, suggesting that many of these RLKs and RLPs are potential PRRs. Analyses of existing PRRs have uncovered ligand-induced RLK-RK or RLK-RP oligomerization as a common mechanism for immune activation. PRRs can recruit additional components to form dynamic receptor complexes, which mediate specific cellular responses. Detailed analyses of these components are shedding light on molecular mechanisms underlying the regulation of PRR activity and downstream signaling.