Identification, Structural and Evolutionary Analysis of Polyprenyl Synthase Gene Family in Tomato and Three Tobacco Varieties

Polyprenyl synthase gene family contained many genes which played key roles in terpenoids biosynthesis. In A. thaliana, 17 polyprenyl synthase genes were already identified which could be divided into 4 major groups as Geranylgeranyl Diphosphate Synthase (GGPPS), Farnesyl Diphosphate Synthase (FPS), Solanesyl Diphosphate Synthase (SPS) and Geranyl Diphosphate Synthase (GPS). In this article, bioinformatics analyses were performed to infer the putative polyprenyl synthase genes of tomato and three tobacco varieties based on whole genome databases. In total, 13 and 32 polyprenyl synthase genes were identified in whole genome of tomato and three tobacco varieties. Phylogenetic analyses showed that they were grouped into three major clades, gps and sps genes shared relative close relationship for one subclade grouping. Besides of these, 10 positive selection sites were identified along the sequences of Sub III clade which contained sps and gps genes. 2 of 10 positive selection sites were mapped onto 3-dimensionmal structures of tomato SPS and GPS sequences, respectively. One positive selection site was neighbor of conserved domain DDXXD, suggesting its important role played in polyprenyl synthase activities. Tomato GGPPS gene only has 1 intron, while other genes have multiple introns.