Genome-Wide Identification and Characterization of Gene Family in (Cucurbitaceae).

is a traditional Chinese medicinal plant of considerable application value and commercial potential, primarily due to its production of various bioactive compounds, particularly dammarane-type triterpenoid saponins that are structurally analogous to ginsenosides. Oxidosqualene cyclase (OSC), a pivotal enzyme in the biosynthesis of triterpenoid metabolites in plants, catalyzes the conversion of oxidosqualene into triterpenoid precursors, which are essential components of the secondary metabolites found in . To elucidate the role of gene family members in the synthesis of gypenosides within , this study undertook a comprehensive genome-wide identification and characterization of genes within and compared their expression levels across populations distributed over different geographical regions by both transcriptome sequencing and qRT-PCR experimental validation. The results identified a total of 11 members of the gene family within the genome of . These genes encode proteins ranging from 356 to 767 amino acids, exhibiting minor variations in their physicochemical properties, and are localized in peroxisomes, cytoplasm, plasma membranes, and lysosomes. All s contain highly conserved DCTAE and QW sequences that are characteristic of the gene family. A phylogenetic analysis categorized the s into four distinct subfamilies. A cis-element analysis of the promoters revealed a substantial number of abiotic stress-related elements, indicating that these genes may respond to drought conditions, low temperatures, and anaerobic environments, thus potentially contributing to the stress resistance observed in . Expression analyses across different populations demonstrated significant variability in gene expression among geographically diverse samples of , likely attributable to genetic variation or external factors such as environmental conditions and soil composition. These differences may lead to the synthesis of various types of gypenosides within geographically distinct populations. The findings from this study enhance our understanding of both the evolutionary history of the gene family in and the biosynthetic mechanisms underlying triterpenoid compounds. This knowledge is essential for investigating molecular mechanisms involved in forming dammarane-type triterpenoid saponins as well as comprehending geographical variations within populations. Furthermore, this research lays a foundation for employing plant genetic engineering techniques aimed at increasing gypenoside content.