玫瑰2-苯乙醇生物合成与转录调控的分子机制研究

Rose (Rosa rugosa) is an excellent landscaping material and a precious natural perfume plants. Rose essential oil is known as ‘liquid gold’ and has high economic and health values. 2-phenylethanol is the main fragrant components of rose flower and essential oil, the regulation and modification of the metabolic pathways of 2-phenylethanol by genetic and metabolic engineering aimed at improving the content of rose essential oil will have important theoretical and practical significance. Based on the previous studies, this project aimed to tap the key genes regulating 2-phenylethanol biosynthesis from R. rugosa through the full metabolic pathway, to screen the transcription factor regulating the above key genes, and to analyze the temporal and spatial expression patterns and transcriptional activation activity of the transcription factor; Subsequently, overexpressed vectors of the key genes and transcription factors shall be constructed and transferred into petunia based on agrobacterium-mediated genetic transform.The purpose is to identify their function by analyzing the differences in floral scent composition between the transgenic plants and control plants, and the differences in transcript expression will also be analyzed to screen genes regulated downstream by the transcription factors using bioinformatics analysis, to reveal the gene network in the transcription factor involved in regulation of the synthesis of 2-phenylethanol. Take together, the present proposal will disclose the molecular mechanism of 2-phenylethanol biosynthesis and transcriptional regulation in R. rugosa. Therefore, this study can enrich the theory of 2-phenylethanol metabolism and regulation in plants, and lay the foundation for creating new germplasm of R. rugosa with improved essential oil content, genetic resources for the molecular improvement of the aroma quality of some other commercial flowers shall be provided as well.

玫瑰是优良的园林绿化材料和珍贵的天然香料植物，玫瑰精油被誉为“液体黄金”，经济和保健价值极高。2-苯乙醇是玫瑰精油的主要芳香成分，采用基因工程手段调控2-苯乙醇代谢途径，开展以提高玫瑰精油含量为目标的代谢工程研究具有重要的理论意义和应用价值。本项目拟在前期研究的基础上，进一步从全代谢通路上挖掘调控玫瑰2-苯乙醇生物合成的关键基因，分离调控关键基因的转录因子，检测其时空表达模式和转录激活活性；构建关键基因和转录因子的超表达载体并转化矮牵牛，观测超表达合成基因及转录因子对2-苯乙醇含量的影响；通过分析转基因植株与对照株系转录本表达的差异，筛选出受转录因子调控的候选下游基因，探讨转录因子参与2-苯乙醇合成调控的基因网络，最终阐释我国传统玫瑰中2-苯乙醇生物合成与转录调控的分子机制，从而丰富植物2-苯乙醇代谢与调控的理论，为接下来创制“高油”玫瑰新种质及其它商品花卉香气品质的分子改良奠定基础。

玫瑰是优良的园林绿化材料和珍贵的天然香料植物，玫瑰精油被誉为“液体黄金”，经济和保健价值极高。2-苯乙醇是玫瑰精油的主要芳香成分，采用基因工程手段调控2-苯乙醇代谢途径，开展以提高玫瑰精油含量为目标的代谢工程研究具有重要的理论意义和应用价值。本项目初步探明了玫瑰花中精油的合成与分泌机制，发现使用0.25%茉莉酸甲酯溶液喷洒玫瑰植株可导致玫瑰花香气成分释放总量明显增加。在此基础上，克隆了玫瑰中2-苯乙醇生物合成途径中的RrAAAT、RrPPDC1、RrPPDC2、RrAADC和RrPAR基因，分析了其时空表达规律，以及玫瑰花中2-苯乙醇积累与基因表达的关系；构建了玫瑰2-苯乙醇合成相关基因的超表达载体，并转入矮牵牛验证其功能，发现转RrPPDC1基因的矮牵牛花朵变大，转RrAADC和RrAAAT基因植株花朵中2-苯乙醇的含量较对照株均有明显增加，个别转基因植株2-苯乙醇的含量为对照株的2倍以上，挖掘出了调控玫瑰2-苯乙醇代谢的关键基因，并初步探讨了玫瑰 2-苯乙醇生物合成与代谢的分子调控机制；克隆获得了与玫瑰2-苯乙醇合成的底物L-苯丙氨酸合成相关的RrDHQ/SDH、RrCM1和RrCM2基因，以及两个R2R3-MYB家族转录因子RrODO1和RrMYB114，分析了其时空表达特性，构建了这些基因的超表达载体并转入矮牵牛验证其功能。表型观察发现，转RrMYB114基因的矮牵牛植株形花中主要芳香物质的含量高于野生型植株，尤其是苯类/苯丙素类芳香化合物变化较为显著，转RrMYB114基因植株中2-苯乙醇的含量是野生型矮牵牛植株的10倍左右，可能是调控玫瑰2-苯乙醇合成的关键转录因子。本项目的完成不仅可以发掘我国传统玫瑰中2-苯乙醇生物合成的关键基因及转录因子，揭示其调控玫瑰2-苯乙醇合成的分子机制，还可为接下来创制“高油”玫瑰新种质及其它商品花卉香气品质的分子改良奠定基础。

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