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MEP途径定位于植物细胞的质体中,为包括青蒿素在内的萜类合成提供基本前体。2-C-甲基-D-赤藓醇-4-磷酸胱氨酰转移酶(2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase,MCT)是该途径的第3个关键酶,催化2-C-甲基-D-赤藓醇-4-磷酸生成4-(5’-焦磷酸胞苷)-2-C-甲基-D-赤藓醇。本文首次克隆了青蒿MCT基因全长cDNA(AaMCT)并进行了相关生物信息学分析。基因表达结果表明:AaMCT在青蒿分泌型腺体中大量表达,在叶、花、茎和根中少量表达;同时发现,AaMCT表达受到MeJA强烈诱导。亚细胞定位结果显示:AaMCT融合GFP特异性定位在叶绿体中,与MEP途径定位于质体吻合。最后在拟南芥中超量表达AaMCT,拟南芥中叶绿素a、叶绿素b和类胡萝卜素含量得到显著提高,表明AaMCT在萜类物质的生物合成中起重要作用。
The MEP pathway is localized in the plastids of plant cells and provides a basic precursor for terpenoid synthesis, including artemisinin. 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase (MCT) is the third key enzyme in this pathway, catalyzing 2 -C-methyl-D-erythritol-4-phosphate to generate 4- (5’-pyrophosphate cytidine) -2-C-methyl-D-erythritol. This article cloned the first full-length cDNA of Artemisia annua MCT gene (AaMCT) and related bioinformatics analysis. The results of gene expression showed that AaMCT was abundantly expressed in the secretory gland of A. annua and only a small amount in leaves, flowers, stems and roots. At the same time, AaMCT expression was strongly induced by MeJA. Subcellular localization results showed that AaMCT fusion GFP was specifically located in the chloroplast and was mapped to the plastid by the MEP pathway. Finally, overexpression of AaMCT in Arabidopsis significantly increased chlorophyll a, chlorophyll b and carotenoid content in Arabidopsis, indicating that AaMCT plays an important role in the biosynthesis of terpenoids.