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-质谱法分析了包括中国分类群在内的64种239个栽培品种花的挥发性成分。原产于中国西南地区的月季玫瑰（Rosa chinensis var. spontanea）散发出的1,3,5-三甲氧基苯是月季气味的主要成分。通过1,3,5-三甲氧基苯（TMB）和1,3-二甲氧基-5-甲苯（DMMB）作为关键成分，许多茶月季和月季与祖先种R.chinensis var. spontanea和r.g angantea具有亲缘关系。然而，月季中有一些品种没有这些关键成分，这些品种的来源尚不确定。(2)在分析的古月季中，我们发现有一些品种的挥发性成分与现有月季不同。这些品种是TMB和DMMB排放平衡，TMB或DMMB大量排放和二氢β-离子酮大量排放的品种。这些品种将成为培育新型香玫瑰的宝贵基因资源。(3)从中国蔷薇（Rosa chinensis var. spontanea）花瓣中分离到3种o -甲基转移酶，并测定了它们对底物的偏好。其中一种药物与被认为是TMB前体的3,5-二羟基异唑有效。(4)从中华r.c chinensis var. spontanea花瓣中分离得到甲基化生产中间体3,5-二羟基茴香醚第一步的间苯三酚o -甲基转移酶（POMT），并对其进行纯化。分离出全长的POMT cDNA，并在大肠杆菌中表达。POMT作为玫瑰花香化合物合成的关键酶，在花器官中特异表达。

(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.