Receptor Kinase H13 And Its Homologues Regulate Meristem And Organ Development In Arabidopsis Thaliana

Receptor-like kinases (RLKs) encode plasma membrane-localized proteins that transduce extracellular signals into cells to regulate many aspects of plant growth and development. For example, CLV1 controls the morphology and function of meristem; BRI1 and BAK1 function together in a protein complex to perceive brassinosteoid signals. There are more than 600 RLKs in Arabidopsis. Although some of them were reported with important roles, biological functions of most RLKs have not been revealed yet.Single and higher order T-DNA insertion mutants of homologous RLKs H6, H10, H12 and H13 were obtained for further functional analyses. The single knockout mutant of h6, h10, h12 and h13 does not show any obvious phenotypes. However, the quadruple mutant h6/10/12/13 displays fasciated inflorescence that initiates many flowers, but produces severely few seeds due to abnormal growth of ovule and anther. The mutant exhibits clvl and clv3-like phenotypes with plethoric leaf, additional carpels and club-shaped siliques, indicating that H13 and its homologous genes are essential components of the CLV3 pathway. The expression of CLV3 is up-regulated remarkably in the quadruple mutants. Meanwhile, yeast-two-hybrid results suggested that H13 and its homologs could interact with CLV1. Our results indicate that H13 and its homologs probably function as new putative receptors or coreceptors by interacting with CLV1 to perceive ligands like CLV3, then take part in the CLV3-WUS feed back loop signaling pathway to control the development of meristem, pistil and anther in Arabidopsis thaliana.