| he mechanisms that underlie the lack of carotenoid accumulation in rice endosperm were investigated, en route to engineering carotenoid biosynthesis in rice. The genetic capacity to synthesize and accumulate carotenoids in photosynthetic tissues and not in endosperm of rice implies a tissue specific regulation. One of the possible causes of the absence of colored carotenoid accumulation in rice endosperm may be the lack of expression of one or more carotenoid biosynthetic genes. Furthermore, the presence of more than one gene involved in the tissue specific expression of carotenoid biosynthetic enzymes is a possibility too. To investigate the tissue specific regulation, the expression of the first two carotenoid biosynthetic genes, Psy (phytoene synthase) and Pds (phytoene desaturase), in rice was studied.;Results clearly shows that the carotenoid biosynthetic enzymes PSY and PDS were encoded by single copy genes mapped to chromosome... |
