LRR receptor kinase involved in positive regulation of somatic embryogenesis and defense response against the rice blast fungus pathogen Magnaporthe oryzae (PubMed:15968510). Involved in the positive regulation of receptor kinase-mediated immunity. Required for immunity mediated by the LRR receptor kinases XA21 and XA26/XA3 which recognize effectors from the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo). Required for the immune response mediated by the LRR receptor kinase FLS2 which recognizes specifically the bacterial flagellin (flg22) effector. Kinase activity and direct interaction with the immune receptors is critical for their function (PubMed:24482436). Involved in the regulation of plant growth through the brassinosteroid (BR) signaling pathway (PubMed:19754838, PubMed:24482436). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with BRI1 (PubMed:22058019, PubMed:24482436). Interacts with XA21, XA26/XA3 and FLS2 (PubMed:25372696). Expressed in flag leaves (PubMed:11332734). Expressed in roots, shoot apex, leaf blades, leaf sheaths, panicles and flowers (PubMed:16081169). Expressed leaves, stems, sheaths and flowers (PubMed:24482436). Induced by infection with the rice blast fungus Magnaporthe oryzae (PubMed:11332734, PubMed:15968510). Induced by salicylate (SA), jasmonate (JA), abscisic acid (ABA) and benzothiadiazole (BTH) (PubMed:15968510). Autophosphorylated on serine and threonine residues. Plants silencing SERK2 exhibit strong reduction of percentage of shoot regeneration from callus. Plants over-expressing SERK2 show enhanced resistance to the rice blast fungus Magnaporthe oryzae (PubMed:15968510). Plants silencing SERK2 have compromised XA21- and XA3/XA26-mediated immunity to the bacterial leaf blight pathogen Xanthomonas oryzae pv. oryzae (Xoo). Plants silencing SERK2 display altered morphology and reduced sensitivity to the hormone brassinolide (PubMed:24482436). Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.