普通烟草茄尼基焦磷酸合酶基因NtSPS的克隆和表达分析

为揭示烟草茄尼基焦磷酸合酶（Nicotiana tabacum solanesyl diphosphate synthase, NtSPS）在烟草茄尼醇生物合成中的作用，分离了烟草品种红花大金元茄尼醇生物合成关键基因NtSPS1和NtSPS2，并对其进行了序列比对、进化分析和亚细胞定位分析，研究了其在烟草植株不同器官的表达水平以及烟草植株不同器官的茄尼醇、叶绿素含量与NtSPS表达水平的相关性。结果表明，NtSPS1和NtSPS2开放读码框（ORF）大小分别为1209、1206 bp，分别编码402、401个氨基酸；NtSPS1和NtSPS2均存在2个保守的DDxxD结构域，这与NtSPS功能发挥相关；NtSPS1、NtSPS2与番茄SPS同源性较高，这与烟草、番茄均为茄科作物有关；NtSPS1、NtSPS2均定位于叶绿体中；烟草植株不同器官NtSPS1和NtSPS2表达水平排序为：叶 > 茎 > 根，这与茄尼醇、叶绿素在烟草植株中的分布规律一致。本研究可为NtSPS调控烟草茄尼醇生物合成机制的深入研究奠定基础。

Cloning and Expression Analysis of Solanesyl Diphosphate Synthase (NtSPS) Genes in Nicotiana Tabacum

We cloned two solanesyl diphosphate synthase genes, NtSPS1 and NtSPS2, from tobacco (Nicotiana tabacum cv. Honghuadajinyuan) plants to investigate their role in tobacco solanesol biosynthesis. In this study, we performed sequence alignment, phylogenetic analysis, and subcellular localization analysis of NtSPS1 and NtSPS2. Further, we studied the expression levels of NtSPSs in different organs of tobacco plants, and analysed the relationship between solanesol, chlorophyll content and the expression levels of NtSPSs in different organs of tobacco plants. The results showed that:NtSPS1 contained an open reading frame (ORF) of 1209 bp encoding 402 amino acids and NtSPS2 contained an ORF of 1206 bp encoding 401 amino acids. Both NtSPS1 and NtSPS2 had two conserved DDxxD domains, which were related to the function of NtSPS. The homology among NtSPS1, NtSPS2, and SlSPS was very high, probably because both tobacco and tomato were solanaceous crops. Both NtSPS1 and NtSPS2 were located in the chloroplast. The expression levels of NtSPS1 and NtSPS2 in different organs of tobacco plants decreased according to this order:leaf > stem > root, which was consistent with the distribution of solanesol and chlorophyll in tobacco plants. This study could lay a foundation for further research on the role of NtSPSs in the regulation of tobacco solanesol biosynthesis.