S-acylation is a positive regulator of FLS2-mediated plant immunity

Plant receptor kinases are key transducers of extracellular stimuli and are regulated by numerous post-translational modifications. S-acylation involves the addition of long chain fatty acids to cysteine residues within proteins, altering their biophysical properties. Here we identify S-acylation at a conserved cysteine of the receptor kinase FLS2 as being crucial for function during plant immunity. We observe rapid S-acylation of FLS2 upon perception of its flg22 ligand in a BAK1 co-receptor dependent manner. Notably, S-acylation is essential for several aspects of FLS2-mediated early and late signalling, including anti-bacterial immunity. Biochemical analysis suggests that that FLS2 S-acylation assists the stabilisation of activated receptor kinase protein complexes at the plasma membrane to increase signalling efficiency.