ERECTA and BAK1, two receptor-like kinases interact to regulate immune responses in Arabidopsis

Researchers from the CBGP group “Plant innate immunity and resistance to necrotrophic fungi”, in collaboration with Dr. Keiko Torii from Washington University (USA), have demonstrated the role of two membrane receptor-like kinases in the regulation of several Arabidopsis thaliana immune responses.

ERECTA (ER) is a receptor-like kinase that regulates stomatal patterning and floral architecture by interacting with the ER-family members, ERL1 and ERL2, and the receptor-like protein (RLP), TOO MANY MOUTHS (TMM). Moreover, ER controls immune responses and disease resistance to pathogens like the bacterium Pseudomonas syringae pv. tomato DC3000 and the necrotrophic fungus Plectosphaerella cucumerina BMM (PcBMM). Genetic analyses performed by the “Plant innate immunity” group have demonstrated that ER acts in a combinatorial specific manner with ERL1, ERL2 and TMM to control PcBMM resistance. Besides, the RLK BAK1 interacts with ER to regulate this type of defense responses, and both proteins interact in vivo in co-immunoprecipitation experiments in Nicotiana benthamiana. This is the first demonstration of the involvement of this multiproteic receptorsome in the regulation of both stomatal patterning and innate immunity. However, the data by Jordá et al., suggest that the cues (ligands) activating the immunity function of this multiproteic receptorsome are different from those (EPFs peptides) regulating stomatal patterning.