牻牛儿基牻牛儿基焦磷酸合酶(GGPS)在类胡萝卜素的生物合成中起着重要作用。在之前的研究中，我们从一个高类胡萝卜素含量的甘薯品系农大辐14中克隆得到IbGGPS基因, 但其在甘薯类胡萝卜素生物合成中的作用及其调控机制尚未研究。在本研究中，我们将IbGGPS基因导入甘薯品种栗子香中，发现该基因显著增加转基因甘薯块根中的β-胡萝卜素、β-隐黄质、玉米黄质和叶黄素含量。进一步研究表明，IbGGPS基因的过表达使糖酵解途径、MEP途径和类胡萝卜素途径相关基因的表达系统上调，从而增加了转基因植株的类胡萝卜素含量。这些结果表明，IbGGPS基因具有提高甘薯和其他植物类胡萝卜素含量的利用价值。

Geranylgeranyl pyrophosphate synthase (GGPS) plays an important role in the biosynthesis of carotenoids.  In a previous study, the IbGGPS gene was isolated from a sweetpotato, Ipomoea batatas (L.) Lam., line Nongdafu 14 with high carotenoid contents, but its role and underlying mechanisms in carotenoid biosynthesis in sweetpotato were not investigated.  In the present study, the IbGGPS gene was introduced into a sweetpotato cv. Lizixiang and the contents of β-carotene, β-cryptoxanthin, zeaxanthin and lutein were significantly increased in the storage roots of the IbGGPS-overexpressing sweetpotato plants.  Further analysis showed that IbGGPS gene overexpression systematically up-regulated the genes involved in the glycolytic, 2-C-methyl-D-erythritol-4-phosphate (MEP) and carotenoid pathways, which increased the carotenoid contents in the transgenic plants.  These results indicate that the IbGGPS gene has the potential for use in improving the carotenoid contents in sweetpotato and other plants.