Plant receptor kinases

: Recent plant genome analyses have revealed a large number of genes encoding receptor-like kinases (RLKs) in plants. Theyare transmembrane proteins structurally related to the animal tyrosine and serin/threonine families with differences in their extracellular domains. There are more than 20 classes of plant RLKs, distinguished according to their extracellular domains, which can potentially bind an array of molecules. Although the majority of these RLKs remains uncharacterized, several members of this family are known to function in a diverse biological processes including plant growth and development, self-incompatibility, hormone perception and plant-microbe interactions. Despite knowledge of RLKs functions is increasing rapidly, yet major challenges remain. These include identifying ligands that activate RLKs and characterizing downstream pathways.