植物花香因具有重要的生态学功能与潜在的应用价值，促使其生物合成途径的研究颇受注目。植物花香生物合成途径的研究大多基于无外界胁迫的植物中进行，然而在自然界中植物的生长过程遭受许多外界胁迫；而这些胁迫是否会诱导其花香生物合成途径的变化，至今尚未见报道。我们前期的研究表明玫瑰花并不是通过单一的合成途径生成芳香族香气物质（AC），且其主要合成途径可能受温度胁迫的影响而发生变化。本项目以玫瑰花为研究材料，采用同位素示踪、特异性抑制剂阻断路径、基于原生质体建立的RNA干涉等方法，研究在高温胁迫下植物中尚未知的AC上游合成途径(由L-苯丙氨酸经苯丙酮酸形成AC)，包括功能鉴定AC合成相关的芳香族氨基酸转氨酶等，旨在获得高温胁迫诱导AC合成路径变化的可靠证据。本项目有望揭示在高温胁迫下AC的新合成途径，为将来玫瑰花AC基因工程技术的开发与成功应用提供更充分的科学依据。

Recently biosynthesis of floral volatiles has attracted great interest of many researchers, because floral volatiles possess important ecological functions and potential economic applications. Current research on biosynthesis of plant secondary metabolites including floral volatiles are mostly based on the plants unexposed to stress in laboratory experiments. In nature, various abiotic and biotic stresses are involved in growth of plants. However, no information is available on the influences of environmental stresses on biosynthesis of floral volatiles. Our preliminary experiments proposed that rose flowers may produce volatiles such as aroma compounds (AC) via more than one pathway. Furthermore, temperature stresses may induce variation of upstream major pathway of AC. This research proposal will elucidate the putative upstream pathways of AC (the pathway of AC derived from L-phenylalanine via phenylpyruvic acid), which will be investigated in plants for the first time. The aromatic amino acid aminotransferase, which is involved in biosynthesis of AC, will be characterized. Moreover, this research proposal will emphasize investigating mechanism of variation of AC upstream major pathway induced by high temperature stresses. The results obtained within these studies will advance our understanding of biosynthesis and defense strategy of plant secondary metabolites such as volatiles, and also can be essential for the future developments of genetic engineering of aroma compounds of rose flowers.