Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/21/2001
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Carotenoids represent the most diverse and a widely distributed class of pigments in nature. They are important for human health and well-being, because they serve as precursors of vitamin A synthesis, and they may have chemoprotective activity. In spite of recent advances in our understanding of the molecular biology of carotenoid biosynthesis, the mechanisms and signals that regulate carotenogenesis largely remain an enigma. Cauliflower (Brassica oleracea L. var. botrytis) curd normally contains negligible amounts of carotenoids. However, the Or gene causes this structure and other tissues to accumulate large amounts of beta-carotene (Crisp et al., 1975), and we are attempting to elucidate the biochemical, molecular, and cellular changes induced by this gene. We have found no clear association between the presence of the Or gene and differences in plastid isoprenoid and carotenoid biosynthetic gene expression. Although the molecular basis of Or mutation is still open to speculation, our cytological evidence is suggestive of a role for the Or gene in determining plastid fate. In the absence of signals required for chloroplast development, the Or gene may direct plastids to convert into chromoplasts. We are now initiating comparative genomics studies to isolate the Or gene. We hope that by isolating this gene, we will gain new insights into the cellular processes that govern carotenoid synthesis and accumulation in plants. This in turn may identify novel strategies for modifying carotenoid content in other more important crops.