Cloning of β-amyrin synthase gene from Panax quinquefolius and its bioinformatics analysis / 中草药

ABSTRACT

Objective: To obtain the full-length cDNA of β-amyrin synthase (bAS) involved in triterpene saponin biosynthesis in Panax quinquefolius and provide the reference for saponin biosynthesis and the regulation of secondary metabolism in P. quinquefolius. Methods: Based on large-scale ESTs sequencing and RACE technology, the full-length cDNA of P. quinquefolius bAS (PqbAS) was obtained. Results: The full-length cDNA of PqbAS (GenBank No. JX185490) was 2 309 bp which included an open reading frame (ORF) code of 631 amino acid peptide. Common conserved domains of oxidosqualene cyclases (OSCs) were found in PqbAS including active sites and conserved sequence. Singal P4.0 analysis showed that PqbAS was a non-secreted protein. Tmhmm 2.0 analysis showed that PqbAS was a non-transmembrane protein. Real-time fluorescence quantitative PCR analysis showed PqbAS gene expressed in various organs, higher in flowers and stems while relatively lower in roots and leaves. Conclusion: The full-length of bAS is first cloned, which could provide the foundation for the investigation on expression characteristics and its role in synthesis of saponin.