A novel interactor of symbiotic RLKs is involved in nodulation in Lotus japonicus
A. YAMAZAKI (1), Y. Shimoda (2), M. Hayashi (1) (1) Center for Sustainable Resource Science, Riken, Japan; (2) NIAS, Japan

The mutual interaction between legumes and rhizobia leading to root nodule symbiosis requires several receptor-like kinases (RLKs). In response to flavonoids released by hosts, symbiotic rhizobia produce and excrete lipochitooligosaccharides termed nod factors (NFs). These strain-specific signals are perceived by LysM type receptors, which in turn activate downstream events eventually forming nodules that enable plants to fix atmospheric nitrogen. To date, several interactors of symbiotic receptor kinases have been identified, e.g. an E3 ubiquitin ligase PUB1, an Rho small GTPase ROP6, a scaffold protein SYMREM1, and a key enzyme in the mevalonate pathway HMGR. However, the early signal transduction, i.e. NF perception to the calcium spiking, remains mysteries. In order to better-understand the signaling around NF receptors, we performed the yeast two hybrid screening using the NF receptor NFR1 as a bait and found ACRE76 as an NFR1 interactor. ACRE76 contains a transmembrane domain and thus localizes in the plasma membrane. Interestingly, ACRE76 also interacted with the other symbiotic RLK, SymRK, in yeast and in planta. ACRE76 interacted with these two RLKs at the same region, indicating its possible role as a signal mediator between NF receptors and SymRK. Finally, the knockdown of ACRE76 resulted in the attenuation in nodulation. These results indicated the positive role of ACRE76 in nodulation, that could be mediated by its interaction with SymRK.

Abstract Number: C1-4, P2-58
Session Type: Concurrent