Evaluation of transgenic tomato plants expressing an additional phytoene synthase in a fruit-specific manner
Evaluation of transgenic tomato plants expressing an additional phytoene synthase in a fruit-specific manner
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DOI：
10.1073/pnas.241374598
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发表时间：
2002-01-22
影响因子：
11.1
通讯作者：
Bramley, PM
中科院分区：
文献类型：
--
作者：
Fraser, PD;Romer, S;Bramley, PM
来自噬夏欧文氏菌（Erwinia uredovora）的八氢番茄红素合酶（crtB）已经在番茄（Lycopersicon esculentum Mill.）CV. Ailsa克雷格）。通过使用番茄多聚半乳糖醛酸酶启动子实现果实特异性表达，并且通过番茄八氢番茄红素合成酶-1转运序列将CRTB蛋白靶向至质体。初级转化体（TO）的总果实类胡萝卜素比对照高2-4倍，而八氢番茄红素、番茄红素、β-胡萝卜素和叶黄素水平分别增加2.4倍、1.8倍和2.2倍。生物合成相关的类异戊二烯，生育酚质体醌和泛醌，不受类胡萝卜素水平的变化。后代（T-1和T-2代）遗传了转基因和表型。酶活性测定和Western印迹分析表明，CRTB蛋白质位于质体中，具有催化活性，总八氢番茄红素合酶活性升高5-10倍。代谢控制分析表明，额外的八氢番茄红素合酶的存在下，减少了这一步的类胡萝卜素途径的调节作用。其他酶的途径（异戊烯二磷酸异构酶，香叶基香叶基二磷酸合成酶，并将异戊烯二磷酸八氢番茄红素）的活动没有显着改变的存在下的细菌八氢番茄红素合成酶。
Phytoene synthase from the bacterium Erwinia uredovora (crtB) has been overexpressed in tomato (Lycopersicon esculentum Mill. cv. Ailsa Craig). Fruit-specific expression was achieved by using the tomato polygalacturonase promoter, and the CRTB protein was targeted to the chromoplast by the tomato phytoene synthase-1 transit sequence. Total fruit carotenoids of primary transformants (TO) were 2-4-fold higher than the controls, whereas phytoene, lycopene, beta-carotene, and lutein levels were increased 2.4-, 1.8-, and 2.2-fold, respectively. The biosynthetically related isoprenoids, tocopherols plastoquinone and ubiquinone, were unaffected by changes in carotenoid levels. The progeny (T-1 and T-2 generations) inherited both the transgene and phenotype. Determination of enzyme activity and Western blot analysis revealed that the CRTB protein was plastid-located and catalytically active, with 5-10-fold elevations in total phytoene synthase activity. Metabolic control analysis suggests that the presence of an additional phytoene synthase reduces the regulatory effect of this step over the carotenoid pathway. The activities of other enzymes in the pathway (isopentenyl diphosphate isomerase, geranylgeranyl diphosphate synthase, and incorporation of isopentenyl diphosphate into phytoene) were not significantly altered by the presence of the bacterial phytoene synthase.