茎瘤芥BjPKS1基因的克隆及遗传转化

Cloning and genetic transforming of BjPKS1 in tumourous stem mustard(Brassica juncea var. tumida Tsen et Lee)

茎瘤芥(榨菜)具有瘤茎膨大的性状,该特征是一种重要的经济性状。在前期研究中,我们获得一个可能与瘤茎膨大有关的基因片段,该基因与拟南芥PKS1基因相似。通过RACE技术获得了该基因全长序列,命名为BjPKS1。该基因的mRNA序列全长1440bp,其预测的ORF长度为1131bp,编码的氨基酸序列长度为376aa。多序列比对发现,预测的氨基酸序列与其他物种的PKS基因家族蛋白具有高度相似性,在多个区域都高度保守,进化分析显示Bj PKS与拟南芥的PKS1基因关系最近。荧光定量RT-PCR结果显示,该基因在茎瘤芥瘤茎膨大发育的过程中表达量明显上升。将该基因转化拟南芥,转基因植株株高和节间都明显缩短。结果表明BjPKS1可能具有其他物种中同源基因相似的分子功能,其在茎瘤芥瘤茎膨大过程中的作用有待进一步研究。

Tumourous stem mustard （Brassica juncea var. tumida Tsen et Lee） is an economically and nutritionally important vegetable crop of the Cruciferae family that also provides the raw material for Fuling mustard. In the previous studies,a gene may be associated with the tumor stem swelling was obtained,which was similar to PKS1 gene in Arabidopsis thaliana. In this study,through RACE technology,the full lenth sequence was cloned and named BjPKS1. It had 1 440 bp cDNA and a complete opening reading frame （ORF） of 1 131 bp,containing the initial code （ATG） and terminal code （TAG） （accession number： JN714279）. The predicted protein of complete ORF comprised 376 amino acids. From a search for BjPKS1 cDNA and amino acid sequences in the database,it had highly sequence identity with the PKS1 protein from A. thaliana. We proposed that BjPKS1 may play the same role as PKS1. In addition,expression of BjPKS1 in development of tumor stem swelling was studied by quantitative RT-polymerase chain reaction,and the level in tumor stem swelling stage was obviously higher than that in unswelling stage,suggesting that BjPKS1 may be related to tumor stem swelling. The BjPKS was genetic transformed to A. thaliana,and the plant height and internode were significantly shorter than WT.