野菊与观赏菊花香萜类物质差异的分子与生化机制

As the important aesthetic character in Chrysanthemum, floral scent is an important factor determining its economic and ornamental value. The wild Chrysanthemum normally possess stronger floral scent than ornamental cultivars. The difference of complexity and richness of terpenoids contribute significantly to the difference of olfactory sensation between cultivars and wild relatives. In this project, with the representative fragrant cultivars and their wild relatives as the model, we plan to investigate the difference of terpene emission and biosynthesis in floral scent from ornamental Chrysanthemum cultivars and their wild relatives. Based on the quantitative and qualitive analysis of the floral terpene compounds, we intend to thoroughly characterize the Isoprenyl diphosphate synthase (IDS) and Terpene synthase (TPS) by RNA-Seq and transcriptional database screening. By highlighting the gene structure, active motif and biochemical function of IDS and TPS, we aim to clarify the difference of molecular and biochemical mechanisms of floral terpene emission in ornamental cultivars and their wild relatives. This project could assist in hypothesizing the genetic origin of floral scent in Chrysanthemum and lay the foundation to the exploitation of wild Chrysanthemum and breeding of the characteristic fragrant Chrysanthemum cultivars.

花香作为菊花的特色观赏性状，是影响其品质和观赏价值的重要因素。野菊种普遍比观赏菊栽培品种具有更为浓郁的香气特征。花香萜类物质成分多样性和丰富度的差异是造成野菊与观赏菊香气差异的重要原因。本项目拟以典型芳香野菊种和观赏菊品种，作为模式物种，深入研究它们之间花香萜类物质释放和生物合成的差异性。在对萜类成分差异进行分析比较的基础上，通过RNA-Seq测序与转录组数据库筛选，鉴定和克隆萜类物质合成途径中的异戊烯基二磷酸合成酶（IDS）和萜类合成酶（TPS）基因，并重点对这两类合成酶的结构、活性位点及生化功能的差异进行全面比较。从底物充足度和萜类产物多样性两个方面，来阐述野菊和观赏菊中花香萜类物质差异的分子与生化机制。本项目可为研究菊花香气的起源提供依据，并对野菊资源的开发利用和特色香气菊花的育种具有指导性意义。

花香作为菊花的特色观赏性状，是影响其品质和观赏价值的重要因素。野菊种普遍比观赏菊栽培品种具有更为浓郁的香气特征。花香萜类物质成分多样性和丰富度的差异是造成野菊与观赏菊香气差异的重要原因。本项目以典型芳香野菊种和栽培菊品种，作为模式物种，深入研究了它们之间花香萜类物质释放和生物合成的差异性。(1)本研究首先对不同类型菊属植物及不同组织萜类成分差异进行分析比较，揭示了萜类物质释放与合成的定量关系，明确了菊属花中腺毛的类型与释放的相关性。(2)通过RNA-Seq测序与比较转录组数据库筛选，并结合已测序菊属植物基因组，鉴定和克隆萜类物质合成途径中的异戊烯基二磷酸合成酶（IDS）和萜类合成酶（TPS）基因，并重点对TPS结构、活性位点、生化功能的差异进行全面比较，初步阐明了菊属植物IDS与TPS的进化特点。从底物充足度和萜类产物多样性两个方面，阐述了野菊和观赏菊中花香萜类物质差异的分子与生化机制。(3)另外，我们对菊属萜类物质在间接防御和抑菌等方面的生物学功能进行了初步探究。本项目为研究菊花香气的起源提供依据，并对野菊资源的开发利用和特色香气菊花的育种具有指导性意义。