A large family of genes that share homology with CLE domain in Arabidopsis and rice

Thirty-one CLAVATA3/ENDOSPERM SURROUNDING REGION (ESR)-related (CLE) proteins are encoded in the Arabidopsis genome, and they are supposed to function as dodecapeptides with two hydroxyproline residues. Twenty-six synthetic CLE peptides, corresponding to the predicted products of the 31 CLE genes, were examined in Arabidopsis and rice. Nineteen CLE peptides induced root meristem consumption, resulting in the short root phenotype in Arabidopsis and rice, whereas no CLE peptides affected the shoot apical meristem in rice. Database searches revealed 47 putative CLE genes in the rice genome. Three of the rice CLE genes, OsCLE502, OsCLE504 and OsCLE506, encode CLE proteins with multiple CLE domains, which are not found in the Arabidopsis genome, and polyproline region was found between these CLE domains. These results indicate conserved and/or diverse CLE functions in each plant species.