| In the flavor and fragrance industry, oil-bearing roses can be classified as varieties of the genus Rosa for the production of essential oil. With extraordinary value of health care and fragrance, rose flower and rose essential oils are broadly used in food, medicine and chemical industry, etc..It was found out that the oil-bearing rose resources were quite rich in China, but of which the development was rarely. For cultivars, the naming was in a mess, also the essential oil yield rate and quality are in different opinions. To resolve the problems brought by the oil-bearing rose development and for further exploration, utilization and germplasm innovation, this research was conducted. Firstly, the oil-bearing roses were investivated and collected from nationwide. The genetic diversity were studied based on DNA molecular markers, morphological marker and biochemical marker. Then summing up the research of the three parts, the application classification system of oil-bearing roses in China was proposed. The component and content of essential oils of the mainly cultivated oil-bearing roses in China also evaluated. Finally, to explore the factors from the metabolic pathway, a committed upper stream catalyzing enzyme of the terpenoid pathway DXR was cloned, the expression profiling of the gene also analysed. Main results were as follows:1. According to investigations, the oil-bearing rose germplasm is quite rich, with a wide spread in wild species, cultivars in the base and fragrant cultivars in modern rose. Totally, we collected37resources, including species covered all6sections recorded of oil value by Flora of China,28cultivars coming from the rose bases nationwide,2hybrid tea (HT) cultivars. The oil-bearing rose bases in our country could be classified into two types, the native rose bases and the exotic rose bases. At present the two type bases both have the the widening trend, exhibiting the expansion of cultivation scope and area and the diversification of varieties. At the same time, it both have a naming chaos problem resulting from blind introduction. In the production and utilization aspects, it is used for food more for native cultivars, while for essential oil more for cultivars introduced abroad. In short, the processing equipment is uneven and processing techniques is low, lacking of scientific guidance.2. Two molecular methods, chloroplast matK gene sequence comparison and ISSR DNA marker, botanical marker combined with quantitative analysis, biochemical marker with components of rose petals detected by DTD-GC-MS were applied to do clustering analysis for37oil-bearing roses, respectively. Combined clustering analysis of the three parts showed that all cultivars could go into three big groups, most domestic rose cultivars, introduced oil-bearing rose cultivars and HT cultivars. Using the classification of considering overseas oil-bearing rose cultivars as species of sect. Rosa for reference, we placed domestic rose cultivars in Sect. Cinnamomeae. Then the relationship between each section could be reconstructed. The results showed that two molecular dendrograms were similar with Sect. Rosa, HT cultivars, Sect. Chinenses, Sect. Synstylae and a wild species of Sect. Cinnamomeae clustered toghther, and the dendrograms of morphology and biochemical components were similar with Sect. Rosa and Sect. Cinnamomeae clustered nearly. It could be deduced that molecular clustering could reflect evolutionary relationship better, while morphology and biochemical components clustering could reflect similarity better. Aiming at the phenomenon of naming chaos, some unreasonable names of oil-bearing roses were corrected. Based on this, the application classification system of oil-bearing rose in China was proposed, taking the provenance reflected by traditional classification and molecular clustering as benchmark and chemotype reflected by biochemical components clustering as supplement, in combination with cultiv(?) classification based on morphological characters, including four grades, from one to four in the order:Sect./Group, species/Subgroup, cultivar and Local cultivar. The morphology and biochemical characteristics were showed in the form of identification key, by which the integrative eualuation was done for the oil-bearing roses.3. Taking five main rose bases as experimental sites, selecting13varieties of oil-bearing roses as experimental materials, comparison among cultivars, of one cultivar in different areas and among different pretreatment groups were set for accessment, essential oils were distilled using water distillation method with the same distilling conditions and totally16oils were got, then for which the physicochemical index, aroma and essential oil components analysis were made.108components with the relative content exceeding0.05%were found in16essential oils, which could be classified into9types.16essential oils could be divided into4chemotypes according to the its compotents composition:Alcohols-Alkane-Alkene chemotype for the oil-bearing roses introduced abroad (BB, BH, WDM, PDM, GLS and its pretreatment group), Alcohols-Esters-Ketones-Phenols chemotype (CH, MFS, FH, PF), Alcohols-Esters-Phenols chemotype (ZZ and PZ), Alcohols-Esters-Ketones chemotype (PK and KS). Priciple Component Analysis (PCA) of components exceeding0.1%resulting in6main components, the loading value of which could be divided into two types, positive and negative. It was found that there was a law a comparatively higher positive loading value featured with flower, fruit, medicine and oil incense was found to domestic cultivars and higher negative loading value featured with faint, green and wood incense for overseas cultivars. one cultivar in different areas and going through different pretreatment could not change the chemtype, but not for the content of some components which may resulting of fragrance difference. Then the main components and minor fragrant components among different pretreatment analysis showed that pretreatment could increase positive loading value and decrease negative loading value. Finally, correlation analysis between oil status and oil yie(?) rate with certain components or component combinations were made, respectively.4. The components of rose essential oil are mainly monoterpene alcohols, predominantly synthesized through the methylerythritol4-phosphate (MEP) pathway in plants.1-deoxy-D-xylulose5-phosphate-reductoisomerase (DXR) is specified to be a committed upper stream catalyzing enzyme of the MEP pathway. In order to understand more about the role of DXR involved in the rose essential oil biosynthesis at the molecular level, the full-length of DXR cDNA sequence (designated as RhDXR) was isolated and characterized from an oil-bearing rose hybrid cultivar Rosa’Zizhi’. Then it was also be amplified from several other cultivars, based on which comparative and clustering analysis were made. Finally, the expression profiling of the gene was investigated in this research. The full-length cDNA of RhDXR was1915bp, comprising an open reading frame (ORF) of1419bp, encoding an enzyme of472amino acids. A comparative analysis with DXRs of selected species from bacteria to higher plants showed three conserved domains existing in the N-terminal region as other high plant species. Phylogenetic analysis indicated that RhDXR belonged to a higher evolutionary plant group. The genetic relationship constructed based on DXR sequences of6cultivars was the same as it in rose application classification system based on DNA molecular, morphology and biochemical components diversity. Expression profiling analysis revealed relative expression levels of the DXR gene from high to low was receptacle, leaf, sepal, pistil, stamen, and petal for different tissues and full bloom (S3), flower bud (S1), flower in half bloom (S2) for different flower stages. Six cultivars could be classified into two groups according to flower color, and within each group there was positive correlation between expression level of DXR gene and oil yield rate. |
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