| Rose(Rosa rugosa Thunb.)is an important ornamental plant of Rosaceae.With unique shape,colorful flowers and strong resistance,rose are widely used as a landscape plant.Rose has a potential for economic growth as it is an important material to extract essential oils.Flavonoids are secondary metabolites of plants,which have an important effect on the color formation of flowers.They also have stronger antioxidant activity,play a positive role in response to extreme environmental changes and enhance resistance of plants to various diseases or some particular disease.In addition,it has been reported that flavonoids have an important significance on human health.Anthocyanins,proanthocynadins and other flavonoids class may enhance anti-inflammatory mechanism and blood circulation,act as antioxidant and can reduce the risk of coronary heart diseases,inflammation,cancer,etc.At present,the research on flavonoid metabolism pathway is relatively clear,but there are still some concerns that need to be resolved.And Most of the studies on rose are still focus on the traditional breeding and molecular research is limited.By deeply studying of the rose genetic transformation,it is possible to improve the quality of rose by combining modern biotechnology with traditional breeding methods.In this study,we firstly identified 28 conserved genes by analyzing the co-expression network and protein-protein interaction network of the homologous structural genes,which were related to the anthocyanin metabolic pathway of the different species of Rosaceae.And then we selected 35 most homologous genes that are related to color from the Arabidopsis thaliana.Later,we use 35 mutants of candidate genes in Arabidopsis thaliana as the main materials.Through a series of experiments,we had screened out some genes that were related to the flavonoid metabolism,and then studied their function,as well as their homologous genes in rose.We deeply examined the molecular mechanism of flavonoid biosynthetic pathway in order to lay the foundation for the rose breeding.The main results are as follows:1.Observing the characteristics of these mutants,we found that 288 and 95 mutants were obvious.The rosette leaves of the 288 mutants were wider,the petiole was shorter and the internode brances were more as compared with the control.While 95 mutants resulted in dwarfed plant,round rosette leaves,leathery,more petals and bar pods.2.In vitro staining analysis of proanthocyanidion and flavonols from different tissues of Arabidopsis thaliana mutants were carried out by DMACA and DPBA.We concluded that 212,272,288,403,494,550,6506 and 0653 mutants have lower flavonol content.Indicating that the deletion of these genes can led to decreased flavonoid content in Arabidopsis.3.The content of flavonoid in inflorescence of Arabidopsis thaliana mutants was determined by high performance liquid chromatography(HPLC).The results showed that the content of flavonol in212,272,288,403,494,550 and 6506 mutants inflorescence were significantly reduced as compared to the control group.However,the content of flavonol in 0653 mutant was not statistically significant.4.Treating Arabidopsis mutants with different concentration of auxin,shown that under the concentrations of 0.5?M IAA and 0.5?? NAA treatment,mutants respond to auxin as the Col-0 control group.494,550,272,403 amd 6506 mutants have significant differences in root length.While on the cases of 0.5?? NAA,272,288,403,6506 mutants have significant difference in their toor length.5.By carrying out bioinformatics analysis of candidate genes,we found that the candidate genes are highly homologous and conserved to the homologous genes in the rose.And the expression of these genes were consistent with the key enzymes in metabolic pathways of flavonoids in different tissues of Arabidopsis thaliana and rose,we found the similar expression trend on them. |
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