Bioinformatics-based detection of secondary metabolite biosynthetic gene clusters and enzymes involved in terpene synthesis in Citrus sinensis (L.) Osbeck

Plants synthesize primary and secondary metabolites through their biochemical processes. Secondary metabolites are substances with diverse functions, ranging from stress response to pharmaceutical production. Terpenes belong to the category of secondary metabolites. The purpose of this article is to predict the biosynthetic gene clusters of secondary metabolites in the Citrus sinensis, to identify the terpene synthases present in terpene clusters, and to elucidate their functions. Additionally, another goal is to identify the enzymes in orthologous species that are counterparts to these enzymes. The plantiSMASH tool was utilized for the prediction of secondary metabolite biosynthetic gene clusters. Later, enzymes with defined functions in the terpene synthase category were selected, ID numbers were assigned to them, and they were listed as CsTS1-CsTS23. The phylogenetic tree of enzymes belonging to the terpene synthase category was generated using the MEGA11 program and the Interactive Tree Of Life v6.7.3 software. For ortholog analysis, the OrthoDB v11 software was utilized. Following the conducted analyses, a total of 11 putative, 3 alkaloid, 3 lignan, 12 saccharide, 6 terpene, 1 terpene-alkaloid, 2 polyketide, 1 saccharide-terpene, and 1 terpene-saccharide-polyketide gene cluster was identified in the C. sinensis. Furthermore, within the phylogenetic tree of terpene synthases, 3 distinct groups were observed. It was determined that the first group had the highest number of members. In addition, orthologs for CsTS9, CsTS10, CsTS12, CsTS19, and CsTS22 could not be identified in the example species. In conclusion, the determination of gene clusters for secondary metabolites will contribute to studies in diverse fields such as medicine, pharmacy, and agriculture.