Volatile components of tea and china roses and analysis of genetic resources by their biosynthetic genes

（1）采用顶空气相色谱-质谱联用技术（GC-MS）分析了包括中国植物分类群在内的64种239个栽培品种花的挥发性成分。月季原产于我国西南地区的密花藤（spontanea）释放的1，3，5-三甲氧基苯（trimethoxybenzene）含量最高，是月季气味的主要成分。许多茶树和月季与其祖先种月季有亲缘关系。以1，3，5-三甲氧基苯（TMB）和1，3-二甲氧基-5-甲基苯（DMMB）为关键成分，对密穗松和红毛密穗松进行了化学成分分析。然而，在中国玫瑰中，也有一些品种没有这些关键成分，这些品种的起源仍然是不确定的。（2）在分析的中国古代玫瑰中，发现有一些品种的挥发性成分与现存的中国玫瑰不同。这些品种是TMB和DMMB释放平衡好、TMB或DMMB释放量大、二氢-β-紫罗兰酮释放量大的品种。这些品种将是培育新型香玫瑰品种的宝贵基因资源。（3）从月季（Rosa chinensis var. spontanea并测定以确定它们的底物偏好。其中之一与3，5-二羟基苯甲醚（TMB的推定前体）作用良好。（4）间苯三酚O-甲基转移酶（POMT）是从月季（R.chinensis var.）spontanea和纯化。分离全长POMT cDNA并在大肠杆菌中表达。POMT在玫瑰花器官中特异表达，是合成玫瑰花香味物质的关键酶。

(1)The volatile components from the flowers of 64 species and 239 cultivars including Chinese taxon were analysed by using GC-MS in the head-space GC analysis. Rosa chinensis var. spontanea, native to south-western China, emitted the greatest amount of 1,3,5-trimethoxybenzene as a key component of Chinese rose odor. Many of tea and china roses had genealogical relationship to ancestral species, R.chinensis var. spontanea and R.gigantea, through 1,3,5-trimethoxybenzene(TMB) and 1,3-dimethoxy-5-methylbenzene(DMMB) as the key components. However, among Chinese roses, there were some cultivars without these key components and it remains to be uncertain about the origin of those cultivars.(2)Among analysed ancient Chinese roses, we found that there were some cultivars emitted composition of volatile components different from existing Chinese roses. These are cultivars emitted well-balanced of TMB and DMMB, large quantity of TMB or DMMB and large quantity of dihydro-β-ionone. These cultivars will be valuable gene resources to breed new type fragrant roses.(3)Three O-methyltransferases were isolated from flower petals of Rosa chinensis var. spontanea and assayed to determine their substrate preferences. One of them workes well with 3,5-dihydroxyanisole, a putative precursor of TMB.(4)Phloroglucinol O-methyltransferase(POMT), which methylates the first step to produce the intermediate 3,5-dihydroxyanisole, was isolated from flower petals of R.chinensis var. spontanea and purified. The full-length POMT cDNA was isolated and expressed in Escherichia coli. POMT was expressed specifically in floral organs in accordance with its role as a key enzyme in the synthesis of rose floral scent compounds.