林下三七花PnAACT基因的克隆及表达模式分析OA

The AACT gene is a key enzyme gene in the mevalonic acid(MVA)pathway for triterpenoid saponin biosynthesis.However,to date,there have been no studies on the variations of the AACT gene in dif-ferent under-planting patterns or at different flowering stages.This study focused on Panax notoginseng flowers in Pinus armandi-P.notoginseng(PAP)and Pinus yunnanensis-P.notoginseng(PYP)agroforestry systems.Based on the transcriptome database of P.notoginseng flowers,primers were designed,and the mevalonic acid(MVA)synthase gene was successfully cloned from P.notoginseng flowers using PCR technology which was designated as PnAACT.The results showed that the open reading frame(ORF)of the PnAACT gene was 1 227 bp in length,encoding 408 amino acids,belonging to an acidic hydrophilic protein without transmembrane re-gions or signal peptides.Phylogenetic analysis revealed that PnAACT shared 99.26％homology with the PvAACT protein from Panax vietnamensis.Meanwhile,the results of real-time fluorescent quantitative PCR(qRT-PCR)demonstrated that the expression of the PnAACT gene was significantly higher at the initial flower-ing stage than that at the full flowering stage of P.notoginseng flowers with the highest expression level ob-served in the PYP agroforestry system.Additionally,the expression of the PnAACT gene in P.notoginseng flowers showed a positive correlation with temperature but negative correlations with humidity and altitude.This study aimed to elucidate the regulatory role of the PnAACT gene in the terpenoid biosynthesis process of P.no-toginseng flowers and provide new research directions for the biosynthesis of saponins and other secondary me-tabolites in P.notoginseng flowers.