Genome-wide identification and expression analysis of the OSC gene family in <i>Platycodon grandiflorus</i>

<i>Platycodon grandiflorus</i> stands as one of the most extensively utilized traditional Chinese medicinal herbs, with triterpenoids and their derivatives serving as its primary medicinal components. Oxido squalene cyclase (OSC), serving as a crucial enzyme in the triterpenoid synthesis pathway, has the capability to enzymatically generate significant quantities of sterols and triterpenoid intermediates. While the <i>OSC</i> gene family has been identified in numerous species, bioinformatics research on this family remains scant. Presently, the specific members of this gene family in <i>Platycodon grandiflorus</i> have yet to be definitively determined. In this study, we successfully identified a total of 15 <i>PgOSC</i> genes within the genome of <i>Platycodon grandiflorus</i> by conducting homology comparisons. These genes were discovered to be unevenly distributed across the five chromosomes of the species, organized in the form of gene clusters. Subsequently, we conducted a thorough analysis of the <i>OSC</i> gene family's evolutionary relationship by constructing a phylogenetic tree. Other characteristics of <i>PgOSC</i> family members, including gene structure, conserved motifs, protein three-dimensional structure, subcellular localization, and cis-acting elements were thoroughly characterized. Furthermore, We analyzed the expression of <i>PgOSC</i> gene in different tissues of <i>Platycodon grandiflorus</i> by qRT-PCR, and found that the expression of <i>PgOSC</i> genes in root was higher than that in stem and leaf. Upon comparing the effects of salt, heat, and drought treatments, we observed a significant induction of <i>PgOSC</i> gene expression in <i>Platycodon grandiflorus</i> specifically under salt stress conditions. In summary, this study comprehensively identified and analyzed the <i>OSC</i> gene family, aiming to provide basic biological information for exploring the members of <i>PgOSC</i> gene family.