Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/16/2005
Publication Date: 7/16/2005
Citation: Chiu, L., Prior, R.L., Wu, X., Li, L. 2005. Toward identification of the candidate gene controlling anthocyanin accumulation in purple cauliflower (brassica oleracea l. var. botrytis). American Society of Plant Biologists Annual Meeting. P. 628.
Technical Abstract: Anthocyanins are the largest group of water-soluble pigments in the plant kingdom that are responsible for the blue, red, and purple color of many fruits, vegetables, grains, flowers, and leaves. In recent years, numerous studies have suggested that anthocyanins serve as valuable diet antioxidants in reducing the risk of a number of human diseases. To gain a better understanding of the regulation of anthocyanin biosynthesis in plants, we are studying a purple cauliflower mutant that exhibits a distinctive purple coloration in curd and young leaves. Biochemical characterization of the mutant showed that cyanidin-(coumaryl-caffeyl)glucoside-5-(malonyl)glucoside is the predominant anthocyanin identified in the purple curd tissue and it accumulates at a level of approximately 2.5 mg of cyanidin equivalent per gram of fresh weight. Microscopy study of the mutant revealed that the anthocyanins accumulate primarily in the axis cells of curd tissue and in the epidermis of young leaves. Examination of the transcript levels of anthocyanin biosynthetic genes and the related transcription factors by Northern blot analysis indicated that while most of the gene examined showed similar levels of expression, the genes encoding dihydroflavonol reductase and anthocyanin synthase are expressed highly in both curd and leaf tissues of the purple mutant in comparison with wild type cauliflower. Preliminary genetic segregation study of the F2 plants appears to suggest that the purple mutation is controlled by a single semi-dominant gene. Candidate gene mapping using a small mapping population of F2 individuals is being carried out to identify the potential gene that controls anthocyanin accumulation in the purple cauliflower.