番茄萜类生物合成途径研究进展

Research advances in terpenoids biosynthesis pathway of tomatoes

番茄中的萜类代谢既对植株本身生长产生影响，又对番茄果实的品质和颜色有着巨大的作用。番茄中大部分萜类化合物均属于类胡萝卜素类，都是通过萜类化合物通路合成的包括3个乙酰辅酶A分子缩合成3．甲基-3，5-二甲基戊酸（MVA），MVA在酶的作用下磷酸化形成焦磷酸酯，脱羧后形成异戊二烯焦磷酸（IPP）；IPP在IPP异构酶（IPPI）的作用下异构化生成甲叉双丙烯焦磷酸（DMAPP），栊牛儿基栊牛儿基焦磷酸合成酶（GGPPS）催化DMAPP与3个IPP分子缩合生成栊牛儿基栊牛儿基焦磷酸（GGPP）。2个GGPP分子在八氢番茄红素合成酶（PSY）的催化下聚合成八氢番茄红素（40碳）；八氢番茄红素脱氢酶（PDS）催化八氢番茄红素成ζ-胡萝卜素，ζ-胡萝卜素在ζ-胡萝卜素脱氢酶（ZDS）的作用下生成番茄红素；在番茄红素β环化酶（LCYb）和ε环化酶（LCYe）的作用下进-步发生环化反应，分别合成仅胡萝卜素和β胡萝卜素；P450类胡萝卜素对此继续作用，通过2步羟化反应生成叶黄素。就番茄中的萜类代谢途径的关键酶基因进行了详细阐述，并对其最新研究进展进行了概括，同时展望了其发展前景。

The metabolic activity of terpenoids not only have a grant effect on normal growth of tomato plants, but also have a great influence on the quality and colour of the fruits. Most terpenoids belong to the carotenoids, which are synthesized through terpenoid pathway. Three acety-CoAs are condensated into one mevalonate （MVA）, which will be phosphorylated into diphosphate, then turn into isopentenyl diphosphate （IPP） through decarboxylation. IPP will be isomerased into dimethylallyl diphosphate （DMAPP） by IPP isomerase （IPPI）. Geranyl Ger- anyl diphosphate synthase （GGPPS） catalyze the reaction for DMAPP and IPP. One DMAPP and three IPP molecules condensedintoone GGPP. Two GGPP polymerize into one phytoene by phytoene synthase （PSY）. Phytoene desaturase （PDS） catalyze the phytoene into E-carotene, which catalyzed into lycopene by X-carotene desaturase （ZDS）. Lycopene β cyclase （LCYb） and lycopene β cyclase （LCYe） catalyze the lycopene turn into or-carotene and β-carotene after cyclization reaction. The lutein will be combined after two step of hydroxylation. The latest research advances in terpeniods biosynthesis pathway are summarized in this review and foreground of the field is prospected.