Cloning And Expression Analysis Of Rosa Rugosa Genes Related To The Aromatic Constituents Biosynthesis

Rosa rugosa, a deciduous shrub of the genus Rosa, is a good landscaping materials and very valuable natural fragrant plants. Monoterpenes including citronellol, geraniol, nerol, and its acetic acid ester derivatives are the major headspace compounds of Chinese traditional R. rugosa, By means of analyzing the volatile compounds of the23R. rugosa germplasm resources, we excavated5excellent rose germplasms which had high content of main monoterpenes, and on this basis, we cloned two genes RrDXR and RrAAT which related to the monoterpene biosynthetic pathway by using’Tang zi’for test material, then expression patterns of the two genes in different developmental stages and different organs of R. rugosa were researched, and the relationship of the R. rugosa volatile substances accumulation and the gene expression were analyzed too. The main results are as follows:1> The floral headspace compounds of Chinese Rosa rugosa germplasms that were isolated by an automated headspace sampler with built-in trap, and followed by gas chromatography-mass spectrometry for identification and quantification. Up to33volatile compounds were identified from the23rose germplasms, including nine alcohols, five esters, three alkanes,10terpenes, three aldehydes, two ketones, and one ether. The main floral components identified were2-phenylethanol, β-citronellol, ethanol, n-hexane, cis-geraniol, citronellol acetate, nerol acetate. In short,’Rongchengyesheng’,’tanghong’,’xizi’’miaofengshan’, and’baizizhi’could be considered good materials for extracting rose oil and breeding new cultivars.2、Total RNA of ’Tanghong’ was extracted using the CTAB method, then the full sequence of RrDXR and RrAAT gene which related to the mnoterpene biosynthetic pathway were cloned by RACE method. The full length of RrDXR was1850bp, with the start codon, the complete open reading frame (1419bp), termination codon. the5’non-coding region (225bp), the3’ non-coding region (206bp) and poly (A) tail (12bp), which encodes473amino acids, and the Genbank No. is JN675704; the full length of RrAAT was1702bp, with the start codon. the complete open reading frame (1380bp). termination codon, the5’non-coding region (48bp), the3’non-coding region (274bp) and poly (A) tail (10bp), which encodes460amino acids, and the Genbank No. is JN675705.3、Tanghong’was used as plant material to study the expression patterns of RrDXR and RrAAT in different developmental stages and different organs of R. rugosa by RT-PCR and Realtime-PCR, the relationship of the R. rugosa volatile substances accumulation and the gene expression were analyzed also. We found that the expression level of RrDXR was increasing from bud to bloom stage in R. rugosa, strongest at bloom and weakest at senescence stage. The expression level of RrDXR was highest in rose petals, in the stamens and pistils the content level were only47.2%and44.3%of the petals, Nor in the calyx, receptacle and pedicel. The gene expression level of RrAAT was low at bud stage of R. rugosa, but followed by the opening stage. the level rapid rise and get highest in the halfopen period. In the full bloom stage, the expression level weakened to47.4%of the previous period and lowest at senescence stage. The gene expression levels of RrAAT in the stamens was strongest in the stamens, while the level was only32.7%of the stamens in the petals, as well as low expression in the pedicel and receptacle.almost nothing in the calyx and pedicel. Then the content of the monoterpenes and its acetic acid ester compounds which controlled by RrDXR and RrAAT in the different developmental stages and different flower organs were determined, and we found the variation pattern was consistent to the RrDXR gene expression; RrAAT gene expression was highest in the halfopen period, but the acetic acid ester compounds was most in the full bloom stage, comprehensive analysis that RrDXR and RrAAT genes play a key role in the biosynthesis of the aromatic components.