白菜型油菜八氢番茄红素合酶基因BrPSY的克隆与序列分析

八氢番茄红素合酶（PSY）是类胡萝卜素合成途经的第一个关键限速酶，对类胡萝卜素合成起着重要的控制作用。本研究利用电子克隆技术，从油菜EST数据库中找到与拟南芥PSY，基因高度同源的油菜EST序列，通过人工拼接及lit—PCR、RACE的方法，克隆得到白菜型油菜BrPSY基因全长eDNA的序列，提交GenBank，被命名为BrPSY（GenBank登记号EUl38883）。BrPSY包含168bp的5’前导序列、69bp的3’不翻译序列和1278bp的完整开放读码框（ORF），编码47．6kOa的蛋白质。序列比对结果表明，BrPSY蛋白与其它植物的PSY蛋白具有很高的相似性；系统进化树分析表明，BrPSY与拟南芥亲缘关系最近。在全长eDNA序列的基础上，设计引物从白菜型油菜DNA中克隆得到BrPSY基因的全长DNA序列，含有7个外显子和6个内含子。

Cloning and analyzing BrPSY gene of carotenoids biosynthesis in Brassica rapa L.

Phytoene synthase （PSY） is a key enzyme in carotenoid biosythesis pathway. A highly homologous PSY gene to the AtPSY from Arabidopsis, was obtained from rape EST database by in silico cloning. The putative full length PSY cDNA of Brassica rapa L. , named as BrPSY （ accession number GQ200740 ） , was assembled and cloned through RT- PC R and RACE. BrPSY had 1 515bp including 168hp of 5＇ leader sequence, 69bp of 3＇ UTR and 1 278bp of open reading frame （ ORF）. BrPSY protein was highly homologous to other PSY protein in different species and was more related to that from Arabidopsis thaliana. Its full length DNA was 2 690bp including 7 exons and 6 introns.