关键词: 桂花, 香气, 芳樟醇及其衍生物, 芳樟醇合酶基因, 表达分析, 功能鉴定

Abstract: This study was conducted to isolate a linalool synthase gene from Osmanthus fragrans Lour.‘Lianzi Dangui’based on genome sequences. Functional identification，expression analysis and the relation with aroma compound formation were investigated. The gene was designated as OfTPS5（GenBank accession No. MN366471）. Sequence analysis demonstrated that the open reading frame（ORF）was 1 770 bp，and putatively encoded 589 amino acids. The OfTPS5 contained conserved domains and belonged to TPS-g subfamily. Multiple sequence alignment analysis demonstrated that it has approximate 50% homology with other plant TPSs. The transcript expression of OfTPS5 reached high level at the full bloom stage with a significant circadian rhythm，which also showed positive correlation with the aroma compound formation. Further transient expression in tobacco leaves proved that OfTPS5 was capable of producing linalool. Thus，OfTPS5 might play an important role in terpenoid biosynthesis in O. fragrans flowers.

Key words: Osmanthus fragrans, aroma, linalool and its derivatives, linalool synthase gene, expression analysis, functional characterization