CHALCONE SYNTHASE IN RICE (ORYZA-SATIVA L) - DETECTION OF THE CHS PROTEIN IN SEEDLINGS AND MOLECULAR MAPPING OF THE CHS LOCUS

The chalcone synthase is a key enzyme that catalyses the first dedicat ed reaction of the flavonoid pathway in higher plants. The chs gene an d its protein product in rice has been investigated. The presence of a chalcone synthase (CHS) protein in rice seedlings and its development al stage-specific expression has been demonstrated by western analysis . The chalcone synthase of rice was found to be immunologically simila r to that of maize. A rice cDNA clone, Os-chs cDNA, encoding chalcone synthase, isolated from a leaf cDNA library of an indica rice variety Purpleputtu has been mapped to the centromeric region of chromosome 11 of rice. It was mapped between RFLP markers RG2 and RG103. RG2 is the nearest RFLP marker located at a genetic distance of 3.3 cM. Some seg ments of chromosome 11 of rice including chs locus are conserved on ch romosome 4 of maize. The markers, including chs locus on chromosome 11 of rice are located, though not in the same order, on chromosome 4 of maize. Genetic analysis of purple pigmentation in two rice lines, Abh aya and Shyamala, used in the present mapping studies, indicated the i nvolvement of three genes, one of which has been identified as a domin ant inhibitor of leaf pigmentation. The Os-chs cDNA shows extensive se quence homology, both for DNA and protein (deduced), to that of maize, barley and also to different monocots and dicots.