白菜型油菜八氢番茄红素脱氢酶基因PDS3的克隆与序列分析

利用电子克隆技术,从数据库中找到与拟南芥高度同源的油菜EST序列,继而通过RT-PCR和RACE等方法,成功克隆了白菜型油菜八氢番茄红素脱氢酶（类胡萝卜素合成途径中的一个关键限速酶）基因PDS3的cDNA,命名为BrPDS3（GenBank登记号GQ200741）。cDNA序列全长1 940bp,其中包含114bp的5＇前导序列和134bp的3＇不翻译序列,编码区长度为1 692bp,编码63kD的蛋白。序列分析表明,BrPDS3蛋白与其他植物的PDS蛋白具有较高相似性;在系统进化树中,BrPDS3与甘蓝亲缘关系最近。根据全长cDNA序列设计引物,从白菜型油菜青油13号DNA中克隆得到BrPDS3基因的全长DNA,长度为3 911bp,ORF（开放阅读框）1 692bp,含有15个外显子和14个内含子。

Cloning and analyzing BrPDS3 gene of phytoene desaturase in Brassica rapa L.

Using in silico cloning method,a phytoene desaturase gene was obtained from Brassica rapa EST database.It was named as BrPDS3（accession number GQ200741）,encoding a key enzyme in carotene biosythesis pathway.By RT-PCR and RACE methods,BrPDS3 cDNA putative full length was assembled 1 940bp long,including 114bp 5′ UTR（untranslated region）,134bp 3′ UTR and 1 692bp ORF（open reading frame） coding a 63kD protein.BrPDS3 protein was highly homologous to other PDS3 proteins from different species.Phylogenetic analysis indicated its close relationship to B.oleracea.BrPDS3 DNA sequence was 3 911bp including 15 exons,14 introns.