过表达Lcy-b基因对烟草类胡萝卜素代谢及香气物质的影响  

Effects of overexpression lycopene beta-cyclase gene on carotenoids metabolism and aroma compounds in tobacco

作　　者：杨永霞[1] 张嘉炜[1] 张洪映[1] 张松涛[1] 贾宏昉[1] 崔红[1] 

机构地区：[1]国家烟草栽培生理生化研究基地,河南农业大学烟草学院,郑州市450002

出　　处：《中国烟草学报》2016年第3期94-100,共7页Acta Tabacaria Sinica

基　　金：中国烟草总公司特色优质烟叶开发重大专项浓香型项目(110200902045 TS-01)

摘　　要：为揭示类胡萝卜素代谢关键基因番茄红素β-环化酶基因(Lycopene beta-cyclase,Lcy-b)对类胡萝卜素及香气物质代谢的影响,通过同源克隆法获得烟草品种K326 Lcy-b基因c DNA全长序列。采用农杆菌介导法导入烟草,测定Lcy-b过表达对类胡萝卜素各组分及烤后样香气物质含量的影响。序列分析表明:K326 Lcy-b基因包含一个1503bp的开放读码框(ORF),编码500个氨基酸。预测蛋白二级结构以α螺旋和无规则卷曲为主,蛋白质分子量为56.06KDa,理论等电点(p I)为6.98。部分过表达阳性植株Lcy-b基因的表达量显著高于对照,类胡萝卜素组分中的β-胡萝卜素、新黄质、紫黄质比例增加,叶黄素所占比例降低。过表达植株烤后样β-胡萝卜素降解产物显著高于对照,而叶黄素降解产物则低于K326对照或与对照相当。研究结果说明Lcy-b过表达可以改变烟草类胡萝卜素组分比例,影响烤后烟叶香气物质含量。In order to reveal function of lycopene beta-cyclase （Lcy-b） gene in the growth and development of tobacco plants, especially its influence on aroma substance metabolism, full-length cDNA sequence of Lcy-b was cloned from tobacco variety K326 homology cloning strategy and effects of overexpression of lycopene beta-cyclase gene on carotenoid components and aroma compounds were determined by agrobacterium-mediated transformation. Sequences analysis showed that tobacco Lcy-b contained 1503-bp open reading frame （ORF） and coded 500 amino acid residues, the calculated molecular mass was 56066.12Da with theoretical isoelectric point （pI） of 6.98. Secondary structure prediction results showed that they were mainly made up of alpha helix and random coil. The expression of Lcy-b gene was significantly higher in some of the transgenic positive plants than that of K326 untransformed control. Correspondingly, the proportion of beta-carotene, neoxanthin and violaxanthin increased and the proportion of lutein reduced. Aroma substance in the cured leaves also displayed that the amounts of beta-carotene degradation products were significantly higher in transgenic positive plants than that of K326 untransformed control while the lutein degradation products were equivalent to or lower than that of K326 control. These results showed that Lcy-b could change the proportion of carotenoid components and affect the content of aroma components in cured samples.

关 键 词：烟草 Lcy—b基因 过表达 类胡萝卜素 香气物质 

分 类 号：S572[农业科学—烟草工业]