Science Express


—The receptor kinase FER is a RALF-regulated scaffold controlling plant immune signaling

Science, (2017); 

This paper by Stegmann et al. is particularly interesting because it sheds a new light on the receptor-ligand mode of action, and also addresses the larger question of pleiotropy in signaling. The FERONIA plant receptor like kinase had previously been shown to play a role in ovule fertilization, growth control, mechanoperception, pathogen response and to genetically interact with a number of hormone signaling pathways.

Here, Stegmann et al. show that FER physically interacts with two major receptors for pathogen perception, namely FLS2 and EFR, as well as their co-receptor BAK1. But most importantly, they reveal that the presence of FER largely promotes the FLS2-BAK1 and EFR-BAK1 complex formation, and that small peptides of the RALF family, the FER ligands, can inhibit this complex formation, thus making the plant sensitive to pathogens.

More globally, this finding raises the question of whether this new FER feature, namely scaffolding receptor complex formation, is a particular case or is the general mode of action of FER in other pathways. For example, one may envision that FER is not a mechanoreceptor by itself, but that it serves as a scaffold for mechanoreceptor complexes.