A novel gene mutation that confers abnormal patterns of β-carotene accumulation in cauliflower (Brassica oleracea var. botrytis)
Article first published online: 23 DEC 2001
The Plant Journal
Volume 26, Issue 1, pages 59–67, April 2001
How to Cite
Li, L., Paolillo, D. J., Parthasarathy, M. V., DiMuzio, E. M. and Garvin, D. F. (2001), A novel gene mutation that confers abnormal patterns of β-carotene accumulation in cauliflower (Brassica oleracea var. botrytis). The Plant Journal, 26: 59–67. doi: 10.1046/j.1365-313x.2001.01008.x
- Issue published online: 23 DEC 2001
- Article first published online: 23 DEC 2001
- Received 23 October 2000; revised 19 January 2001; accepted 29 January 2001.
- carotenoid biosynthesis;
- gene expression;
- sequestering structure
The Or gene of cauliflower (Brassica oleracea var. botrytis) causes many tissues of the plant to accumulate carotenoids and turn orange, which is suggestive of a perturbation of the normal regulation of carotenogenesis. A series of experiments to explore the cellular basis of the carotenoid accumulation induced by the Or gene was completed. The Or gene causes obvious carotenoid accumulation in weakly or unpigmented tissues such as the curd, pith, leaf bases and shoot meristems, and cryptically in some cells of other organs, including the roots and developing fruits. The dominant carotenoid accumulated is β-carotene, which can reach levels that are several hundred-fold higher than those in comparable wild-type tissues. The β-carotene accumulates in plastids mainly as a component of massive, highly ordered sheets. The Or gene does not affect carotenoid composition of leaves, nor does it alter color and chromoplast appearance in flower petals. Interestingly, mRNA from carotenogenic and other isoprenoid biosynthetic genes upstream of the carotenoid pathway was detected both in orange tissues of the mutant, and in comparable unpigmented wild-type tissues. Thus the unpigmented wild-type tissues are likely to be competent to synthesize carotenoids, but this process is suppressed by an unidentified mechanism. Our results suggest that the Or gene may induce carotenoid accumulation by initiating the synthesis of a carotenoid deposition sink in the form of the large carotenoid-sequestering sheets.