Abstract
A rice mutant, rod-like lemma (rol) has pleiotropic phenotypes in spikelet. In rol spikelet, the lemma is replaced by a rod-like structure and the stamen has an abnormal anther on its top. These phenotypes seem to be associated with a defect of organ development along the adaxial-abaxial axis. Thus, rol mutation is likely to affect regulation of the adaxial-abaxial polarity.
Establishment of the adaxial-abaxial polarity is required for expression of the genes that function specifically in the adaxial or abaxial side. In rice, the OsETTIN (OsETT) genes, orthologs of Arabidopsis ETTIN/ARF3, are specifically expressed in the abaxial side. Expression analysis showed the OsETT genes were ectopically expressed in rol mutant. This suggests a possibility that the ectopic expression of the OsETT genes would be associated with morphological defects in rol mutant. To assess this possibility, we tried to suppress the OsETT genes in rol mutant by RNA silencing. The result demonstrated the suppression of the OsETT genes rescued some aspects of rol phenotypes. Thus, this result indicated that ectopic expression of the OsETT genes was one of the causes of rol phenotype.
