| Abstract: | Like in animals, cell surface and intracellular receptors mediate immune recognition of potential microbial intruders in plants. Membrane‐localized pattern recognition receptors (PRRs) initiate immune responses upon perception of cognate microbe‐associated molecular patterns (MAMPs). MAMP‐triggered immunity provides a first line of defence that restricts the invasion and propagation of both adapted and non‐adapted pathogens. The Leu‐rich repeat (LRR) receptor protein kinases (RKs) define a major class of trans‐membrane receptors in plants, of which some members are engaged in MAMP recognition and/or defence signalling. The endoplasmic reticulum (ER) quality control (QC) systems monitor N‐glycosylation and folding states of the extracellular, ligand‐binding LRR domains of LRR‐RKs. Recent progress reveals a critical role of evolutionarily conserved ERQC components for different layers of plant immunity. N‐glycosylation appears to play a role in ERQC fidelity rather than in ligand binding of LRR‐RKs. Moreover, even closely related PRRs show receptor‐specific requirements for N‐glycosylation. These findings are reminiscent of the earlier defined function of the cytosolic chaperon complex for LRR domain‐containing intracellular immune receptors. QC of the LRR domains might provide a basis not only for the maintenance but also for diversification of recognition specificities for immune receptors in plants. |
