过表达三七PnSS基因对烟草萜类物质含量及生长发育的影响

Effects of overexpression of PnSS gene from Panax notoginseng on tobacco terpenoid contents and plant growth and development

为明确PnSS基因在调节烟草萜类物质含量中的作用,构建了PnSS基因过表达载体,并通过叶盘法转化烟草品种巴斯玛14号,获得了PnSS基因过表达烟草植株,最后利用HS-SPME-GC/MS分析转化烟草叶片中的香味物质含量(质量分数)。结果表明:①PnSS的氨基酸序列与其在烟草中同源物NtSS具有81.9%的一致性,并含有角鲨烯和植烯合成酶结构域。②PnSS基因的过表达导致烟草植株变矮、叶片变小;与根和茎相比,叶片中PnSS基因表达量最高。③PnSS基因的过表达使烟叶中乙酸、糠醇、4,6-二甲基嘧啶、苯乙醛、3,5-二甲基苯甲醛、二烯烟碱、二氢猕猴桃内酯、2-甲基吡嗪、壬酸、异戊醛、2-甲基丁醛、西松烯和烟碱13种香味物质含量增加,2,3-二氢-3,5二羟基-6-甲基-4(H)-吡喃-4-酮、2,3-联吡啶、植醇、苯乙醇、新植二烯、苯甲醛和麦斯明7种香味物质含量降低。因此,过表达PnSS基因会抑制烟草植株的生长发育并改变烟叶中萜类物质等香味物质的含量。

In order to clarify the role of PnSS gene in regulating the terpenoid contents in tobacco,an overexpression vector of PnSS gene was constructed.Tobacco cultivar Basma 14 was transformed by the leaf disc method,and the tobacco plants with overexpression of PnSS gene were obtained.The contents(mass fractions)of aroma components in the transformed tobacco leaves were analyzed by HS-SPME-GC/MS.The results showed that:1)The consistency between amino acid sequences of PnSS and homolog NtSS in tobacco were 81.9%.PnSS and NtSS contained squalene and phytoene synthase domains.2)Overexpression of PnSS gene resulted in shorter tobacco plants and smaller leaves.Compared with roots and stalks,the relative expression level of PnSS gene in tobacco leaves was the highest.3)Overexpression of PnSS gene increased the contents of 13 aroma components,including acetic acid,furfuryl alcohol,4,6-dimethylpyrimidine,phenylacetaldehyde,3,5-dimethylbenzaldehyde,diene nicotine,dihydroactinidiolide,2-methylpyrazine,nonanoic acid,isovaleraldehyde,2 methyl butyl aldehyde,cembrane and nicotine in tobacco leaves.The treatment decreased the contents of 7 aroma components,including 2,3-dihydro-3,5 dihydroxy-6-methyl-4(H)-pyran-4-one,2,3-bipyridine,phytol,phenylethanol,neophydiene,benzaldehyde and mesmin.Therefore,the overexpression of PnSS gene inhibited the growth and development of tobacco plants and changed the contents of aroma components,such as terpenoids,in tobacco leaves.