栀子果实中八氢番茄红素脱饱和酶基因的克隆与表达分析

Cloning and expression analysis of a phytoene desaturase gene from Gardenia fruits

[目的]栀子果实中富含类胡萝卜素衍生物—西红花总苷。拟从果实中克隆西红花总苷生物合成途径中的八氢番茄红素脱饱和酶基因。[方法]利用RACE的方法克隆Gj PDS基因,绝对定量PCR法检测在不同组织中的表达。[结果]从果实中克隆了一个长1 746 bp的Gj PDS基因,编码由581个氨基酸组成的八氢番茄红素脱饱和酶序列。与水稻(Oryza sativa)PDS蛋白A链的氨基酸序列有83%的一致性,与菠萝泛菌(Pantoea ananatis)PDS蛋白A链的氨基酸序列一致性低。Gj PDS基因为组成性表达基因,它在栀子果肉中的表达量最高,是叶片中表达量的1.6倍,茎中表达量的3.5倍,种子中表达量的13.1倍。[结论]从栀子果实中克隆了一个1 746 bp的Gj PDS基因,它主要在栀子果肉中表达,可能与西红花总苷的生物合成有关。该基因今后可以用作西红花总苷生物合成途径的调控靶点。

[Objective]Crocins are carotenoid derivative synthesized in Gardenia fruits. A phytoene desaturase gene was cloned from Gardenia fruits and named Gj PDS. Tissue expressions of Gj PDS were analyzed. [Methods] Rapid Amplification of c DNA Ends（ RACE） technique was used to obtain a c DNA encoding the full length Gj PDS gene. Absolute quantitative real-time PCR assay was carried out to characterize the gene＇s expression pattern. [Results]A 1 746 bp Gj PDS gene who encoded a581 amino acids sequence was cloned. Gj PDS was predicted sharing a high similarity with the PDS protein chain A from Oryza sativa and a very low similarity with the PDS protein chain A from Pantoea ananatis. Gj PDS has a constitutive and variable expression pattern in different tissues. The highest expression level was detected in flesh; then the leaves,and the stems; the lowest was detected in seeds. [Conclusion] A 1 746 bp Gj PDS gene was cloning from Gardenia fruits. Gj PDS mainly expressed in flesh of fruits. Gj PDS was a possible target in genetic manipulation of crocin biosynthesis.