Enhancing anthocyanin production by altering competition for substrate between flavonol synthase and dihydroflavonol 4-reductase
Enhancing anthocyanin production by altering competition for substrate between flavonol synthase and dihydroflavonol 4-reductase
复制标题
DOI：
10.1023/a:1024018729349
复制
发表时间：
2003-01-01
期刊：
影响因子：
1.9
通讯作者：
Bradley, JM
中科院分区：
文献类型：
--
作者：
Davies, KM;Schwinn, KE;Bradley, JM
风味物质，特别是花青素，是许多物种花颜色的原因。二氢黄酮醇代表类黄酮生物合成中的分支点，是通过酶二氢黄酮醇4-还原酶（DFR）的作用产生有色花青素和通过黄酮醇合酶（FLS）产生无色黄酮醇的中间体。在这项研究中，白花，黄酮醇积累米切尔线的矮牵牛作为一个模型来检查DFR和FLS酶活性和重定向黄酮类化合物的生物合成远离生产的黄酮醇和花青素的可能性之间的相互作用。引入35 S CaMV-DFR正义转基因构建体引起花青素的产生，导致粉红色花的表型。此外，通过引入FLS反义RNA构建体抑制FLS产生也导致花青素产生和粉红色花表型。两种转基因的组合产生了最高水平的花青素苷形成。花色素苷产生的DFR正义和FLS反义转基因株系，尽管在米切尔线的基因表达水平大大降低的三个酶后期花色素苷生物合成，花青素合酶，UDP-葡萄糖：类黄酮3-O-葡萄糖基转移酶和UDP-鼠李糖：花色素-3-葡萄糖苷鼠李糖基转移酶。因此，可见花青素形成所需的基因活性水平远低于花瓣发育过程中通常诱导的高水平。利用遗传修饰改变DFR和FLS酶活性之间的平衡，可能是在目标观赏物种中引入或增加花青素苷产量的有用策略。
Flavonoids, in particular the anthocyanins, are responsible for flower colour in many species. The dihydroflavonols represent a branch point in flavonoid biosynthesis, being the intermediates for production of both the coloured anthocyanins, through the action of the enzyme dihydroflavonol 4-reductase (DFR), and the colourless flavonols, produced by flavonol synthase (FLS). In this study the white-flowered, flavonol accumulating Mitchell line of petunia was used as a model to examine the interaction between DFR and FLS enzyme activities and possibilities for redirecting flavonoid biosynthesis away from production of flavonols and towards anthocyanins. Introduction of a 35S CaMV-DFR sense transgene construct caused the production of anthocyanins, resulting in a pink-flowered phenotype. Furthermore, inhibition of FLS production through introduction of an FLS antisense RNA construct also led to anthocyanin production and a pink-flowered phenotype. A combination of both transgenes gave the highest level of anthocyanin formation. Anthocyanins were produced in the DFR-sense and FLS-antisense transgenic lines in spite of the greatly reduced levels of gene expression in the Mitchell line for three enzymes late in anthocyanin biosynthesis, anthocyanindin synthase, UDP-glucose: flavonoid 3-O-glucosyltransferase and UDP-rhamnose: anthocyanidin-3-glucoside rhamnosyltransferase. Thus, the level of gene activity required for visible anthocyanin formation is much lower than the high levels normally induced during petal development. Altering the balance between the DFR and FLS enzyme activities, using genetic modification, may be a useful strategy for introducing or increasing anthocyanin production in target ornamental species.