BEAT基因在控制蜡梅乙酸苄酯合成散发中的功能解析

Wintersweet (Chimonanthus praecox) is a traditional fragrant plant in China and the benzyl acetate was the characteristic floral scent consistent. In present, we collected 3 wintersweet genotypes with different scent. The plant materials offers an opportunity to understand the molecular mechanism of the biosynthesis and emission of benzyl acetate in wintersweet. Based on a comparative analysis of transcriptome and proteome between the full open stage flowers of scent and scentless wintersweet genotypes, we surmised that the difference of floral synthesis and emission of benzyl acetate in different wintersweet genotypes is due to a mutation in the benzylalcohol acetyltransferase (BEAT) gene that regulated the biosynthesis of benzyl acetate from benzylalcohol. In this project, we will isolate the cDNA, gDNA and promoter sequences of BEAT from the three genotypes, screen the up-regulated genes which interacted with BEAT gene, then compare the sequences alignment, analyze the expression levels, enzyme activity and function of BEAT, quantitate the endogenous substrate of wintersweet flowers. The results will reveal the molecular mechanism of different emission pattern of benzyl acetate from different scent wintersweet genotypes. This research will provide the knowledge for comprehending the evolution mechanism of wintersweet floral scent.

蜡梅是中国传统的香花植物，乙酸苄酯是蜡梅的特征香气成分之一。项目组前期收集到浓香型、芳香型和无香的3种蜡梅基因型，为研究蜡梅乙酸苄酯合成和散发的分子机理提供了理想材料。苯甲醇乙酰基转移酶基因（BEAT）基因控制乙酸苄酯的合成，前期通过对芳香和无香的蜡梅基因型的转录组和蛋白组比较分析，推测BEAT基因的差异表达可能导致不同芳香蜡梅基因型中乙酸苄酯的差异散发。本项目在已有研究基础上，从3个蜡梅基因型中分离BEAT的cDNA、gDNA和启动子序列，通过对三种材料中基因序列、表达模式、酶活性、基因功能、内源底物含量的分析，以及BEAT基因上游调控基因的筛选，从而揭示BEAT基因在调控不同芳香蜡梅基因型中乙酸苄酯差异合成散发中的作用，这对理解蜡梅花香进化的机理具有重要意义。

按照项目任务书，已经完成蜡梅中BEAT基因的序列的分离及生物信息学分析、时空表达分析、亚细胞定位分析。同时，对蜡梅花中苯甲醇和乙酸苄酯的含量进行测定。对蜡梅中BEAT酶活性进行测定，构建蜡梅花期酵母单杂文库。我们还开展了BEAT基因转化早花烟草以及转基因植株芳香成分的测定。此外，我们还开展了云南不同蜡梅花香物质对节律的反应研究。以及云南蜡梅在整个花期花香的变化等相关研究。我们还开展了对参与云南蜡梅主要花香物质的相关合成基因（5个），进行了克隆和表达分析。3名研究生依托本项目开展了蜡梅相关研究。此外，依托本项目共发表SCI论文3篇，中文核心论文1篇，培养研究生3名顺利毕业。