A novel gene mutation that confers abnormal patterns of β-carotene accumulation in cauliflower (Brassica oleracea var. botrytis)
A novel gene mutation that confers abnormal patterns of β-carotene accumulation in cauliflower (Brassica oleracea var. botrytis)
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DOI：
10.1046/j.1365-313x.2001.01008.x
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发表时间：
2001-04-01
期刊：
影响因子：
7.2
通讯作者：
Garvin, DF
中科院分区：
文献类型：
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作者：
Li, L;Paolillo, DJ;Garvin, DF
花椰菜（Brassica oleracea var.葡萄孢属）引起植物的许多组织积累类胡萝卜素并变成橙子，这表明胡萝卜素生成的正常调节受到干扰。完成了一系列探索Or基因诱导类胡萝卜素积累的细胞基础的实验。Or基因导致类胡萝卜素在弱或无色素的组织如花球、髓、叶基部和茎分生组织中明显积累，并在其他器官的一些细胞中神秘地积累，包括根和发育中的果实。积累的主要类胡萝卜素是β-胡萝卜素，其可以达到比可比较的野生型组织中的水平高几百倍的水平。β-胡萝卜素在质体中的积累主要是作为一个巨大的，高度有序的片层的组成部分。或基因不影响类胡萝卜素的组成，也不改变花瓣的颜色和质体外观。有趣的是，在突变体的橙子组织和可比的无色素野生型组织中检测到类胡萝卜素途径上游的类胡萝卜素和其他类异戊二烯生物合成基因的mRNA。因此，未着色的野生型组织可能有能力合成类胡萝卜素，但这一过程被一种未知的机制抑制。我们的研究结果表明，或基因可能会诱导类胡萝卜素的积累，通过启动类胡萝卜素沉积汇的形式大类胡萝卜素螯合片的合成。
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 beta -carotene, which can reach levels that are several hundred-fold higher than those in comparable wild-type tissues. The beta -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.