茶树CsIDI1和CsIDI2基因的克隆及其表达分析

摘要

该研究在茶树转录组测序基础上,以铁观音品种茶树为材料,采用RT-PCR技术,克隆了茶树异戊烯基焦磷酸异构酶(IDI)的2个编码基因(CsIDI1和CsIDI2)的cDNA全长序列.CsIDI1的全长为1 378 bp,其开放阅读框(ORF)长度894 bp,编码297个氨基酸,亚细胞定位预测位于叶绿体上,其氨基酸序列与葡萄IDI的相似性达95％;CsIDI2的全长为1 216 bp,其ORF长度为717 bp,编码238个氨基酸,亚细胞定位预测位于细胞质上,其氨基酸序列与芝麻IDI相似性达96％.CsIDI2和CsIDI2均含有典型的NUDIX水解酶域.荧光定量PCR结果表明,CsIDI1和CsIDI2基因在茶树地上部不同组织都有表达,但CsIDI2的表达量相对较高;品种间表达量分析显示,它们在父本黄旦品种及杂交后代高香型乌龙茶品种中的表达量显著高于母本铁观音品种,表现出香气上的杂种优势;在乌龙茶做青过程中,随着摇青的进行,CsIDI2的表达被显著诱导,表明CsIDIs在茶叶萜类香气物质形成中发挥重要功能.%Based on the tea plant transcriptome database,we cloned two full-length cDNAs of the isopentenyl diphosphate isomerases (CsIDI1 and CsIDI2) using RT-PCR method from the tea plant cultivar of Tieguanyin.CsIDI1 was 1 378 bp in length and contained a 894 bp ORF encoding 297 amino acids,which shared 95％ similarity with Vitis vinifera IDI.Subcellular localization prediction showed that CsIDI1 was localized to the chloroplast.Additionally,the length of CsIDI2 was 1 216 bp and contained a 717 bp ORF encoding 238 amino acids,CsIDI2 had similarity with 96％ homologous to Sesamum indicum IDI and predicted to was located on the cytoplasm.Both CsIDI1 and CsIDI2 contained a typical NUDIX hydrolase domain.The results of real-time quantitative PCR showed that CsIDI1 and CsIDI2 were expressed in different tissues of tea plant,wherease the expression of CsIDI2 was relatively higher,The expression of CsIDI1 and CsIDI2 was significantly higher in female parent Huangdan and high scent hybrids than that in male parent Tieguanyin,showing the heterosis of aroma.During the green-making procedure of Oolong tea,the expression level of CsIDI2 was significantly higher than that of CsIDI,indicating that CsIDIs play an important role in the formation of tea terpenoids aroma.