LysM-mediated signaling in Marchantia polymorpha highlights the conservation of pattern-triggered immunity in land plants

Pattern-recognition receptor (PRR)-triggered immunity (PTI) wards off a wide range of pathogenic microbes, playing pivotal role in angiosperms. The model liverwort Marchantia polymorpha triggers defense-related gene expression upon sensing components bacterial and fungal extracts, suggesting the existence PTI this plant model. However, molecular putative M. significance bryophytes have not yet been described. We here show that has four lysin motif (LysM)-domain-containing homologs, two which, LysM-receptor-like kinase (LYK) MpLYK1 LYK-related (LYR) MpLYR, are responsible for chitin peptidoglycan fragments, triggering series characteristic immune responses. Comprehensive phosphoproteomic analysis response to treatment identified regulatory proteins potentially shape LysM-mediated PTI. included homologs well-described angiosperms as well whose roles determined, including blue-light phototropin MpPHOT. revealed MpPHOT is required negative feedback during Taken together, study outlines basic framework highlights conserved elements new aspects pattern-triggered land plants.