Seed-specific overexpression of an endogenous Arabidopsis phytoene synthase gene results in delayed germination and increased levels of carotenoids, chlorophyll, and abscisic acid
Seed-specific overexpression of an endogenous Arabidopsis phytoene synthase gene results in delayed germination and increased levels of carotenoids, chlorophyll, and abscisic acid
复制标题
DOI：
10.1104/pp.102.017053
复制
发表时间：
2003-06-01
期刊：
影响因子：
7.4
通讯作者：
Höglund, AS
中科院分区：
文献类型：
--
作者：
Lindgren, LO;Stålberg, KG;Höglund, AS
植烯合成酶催化两个分子的香叶基香叶基焦磷酸二聚为植烯，已被证明是合成类胡萝卜素的限速酶。为了阐明在拟南芥(Wassilewski Ja)种子中是否也限制了生产植酸的能力，我们克隆了一个编码内源植酸合成酶的基因，并将其偶联到一个种子特异的启动子上，并检测了过表达的影响。由此产生的转基因植物产生了更深的种子，从5种过度表达植物的种子中提取的β-胡萝卜素的平均含量增加了43倍，总平均β-胡萝卜素的平均含量约为260杯(-1)鲜重。叶黄素、紫黄质和叶绿素显著增加，而玉米黄质水平仅增加了1.1倍。此外，种子中产生了大量的番茄红素和α-胡萝卜素，而对照植物中只发现了微量的番茄红素和α-胡萝卜素。转基因植株的种子表现出萌发延迟，且延迟程度与类胡萝卜素水平的增加呈正相关。脱落酸水平随着类胡萝卜素含量的增加而增加，类胡萝卜素水平最高的植株也具有最高的脱落酸含量。在生长介质中添加赤霉酸只能部分恢复转基因种子的萌发。
Phytoene synthase catalyzes the dimerization of two molecules of geranylgeranyl pyrophosphate to phytoene and has been shown to be rate limiting for the synthesis of carotenoids. To elucidate if the capacity to produce phytoene is limiting also in the seed of Arabidopsis (Wassilewskija), a gene coding for an endogenous phytoene synthase was cloned and coupled to a seed-specific promoter, and the effects of the overexpression were examined. The resulting transgenic plants produced darker seeds, and extracts from the seed of five overexpressing plants had a 43-fold average increase of beta-carotene and a total average amount of beta-carotene of approximately 260 mug g(-1) fresh weight. Lutein, violaxanthin, and chlorophyll were significantly increased, whereas the levels of zeaxanthin only increased by a factor 1.1. In addition, substantial levels of lycopene and alpha-carotene were produced in the seeds, whereas only trace amounts were found in the control plants. Seeds from the transgenic plants exhibited delayed germination, and the degree of delay was positively correlated with the increased levels of carotenoids. The abscisic acid levels followed the increase of the carotenoids, and plants having the highest carotenoid levels also had the highest abscisic acid content. Addition of gibberellic acid to the growth medium only partly restored germination of the transgenic seeds.