Identification and Tissue-specific Expression Analysis of Oxidosqua-lene Cyclase Gene Family and Cloning of PqOSC2 Gene in Panax quinquefolium
Oxidosqualene cyclase is the key enzyme that catalyzes biosynthesis of triterpenoid sapo-nins,and the identification of oxidosqualene cyclase in Panax quinquefolium is carried out by full-length transcriptome analysis,which provides a basis for the analysis of biosynthesis mechanism of triterpene saponins in P.quinquefolium.In this study,bioinformatics methods were used to identify oxidosqualene cyclase gene family in the transcriptome database of P.quinquefolium and analyze their protein motif,physicochemical properties,and expression characteristics.A total of 15 OSC genes were identified from P.quinquefolium.Phylogenetic analysis grouped them into 7 subfamilies,tissue-specific expression analysis showed that OSC gene family had four expression patterns in dif-ferent tissues,and co-expression analysis of OSC and ginsenosides accumulation showed that OSC family gene was associated with different types of saponins.The full length of PqOSC2 which was positively correlated to the accumulation of ginsenoside Re and Protopanaxatriol was also cloned.This study provides a basis for further revealing the mechanism of the oxidosqualene cyclase family in P.quinquefolium triterpene saponins biosynthesis.