Abstract
The cpm1 mutant of rice is impaired in phytochrome-mediated inhibition of coleoptile growth and in the process of anthesis causing partial sterility (Biswas et al., 2003). The CPM1 locus was mapped to a 143cM region of chromosome 3, in which the ALLENE OXIDE SYNTHASE1 (AOS1) gene is located. The cpm1 mutant was found to have a point mutation in this gene, which is expected to alter one of the amino acid residues conserved in all the reported AOSs. We complemented the cpm1 mutant with the OsAOS1 genomic DNA that included the promoter region. The complemented mutant recovered the phytochrome response and complete fertility, demonstrating that OsAOS1 corresponds to CPM1. The cpm1 mutant had a normal level of OsAOS1 transcripts. It is expected that the mutated protein has a reduced enzyme activity. This possibility is now under investigation. We will also discuss the role played by OsAOS1 in photomorphogenesis.
