Abstract
Recent advances in analyses of CLV3/ESR-related (CLE) peptides have revealed some of their functions in modulating cell proliferation and differentiation, but most of CLE peptide functions remain unknown. Using an Arabidopsis pollen tube culture, we previously found a novel activity of synthetic CLE peptides on promoting the in vitro pollen tube growth. Three receptor-like kinase (RLK) genes expressing in pollen were shown to be responsible for the CLE peptide perception, examining a collection of T-DNA insertion mutants for the in vitro assay. Here we report functional analyses of the selected CLE and RLK genes in Arabidopsis plants. One CLE gene promoter activity was observed in pistil where pollen tubes penetrated. A severe reduction in seed production efficiency was first observed in plants in which the CLE gene expression was down-regulated by RNA interference. A similar defect was found in plants harboring a kinase-dead version of the corresponding RLK gene instead of the wild-type gene. These results indicate the involvement of a novel CLE peptide-mediated signaling in Arabidopsis pollen-pistil interactions for maintaining seed production efficiency.
