Camellia Reticulata Mosaic Virus Identification And Mosaic Color Mechanism Research

Camellia reticulata is an important landscape and garden plants which is enjoyed by the masses of Camellia enthusiasts because of its evergreen leaves and bright colors.However,in the process of cultivation,mosaic disease occurred frequently and by the domestic and foreign research,it found that Camellia yellow mottle virus(CLYMV)is the cause.Although the cultivation area of C.reticulate has been continuously expanded,but for the pathology and coloring mechanism of mosaic disease,the relative reports were very few.Electron microscopy and small RNA high-throughput sequencing technologies were used to identify the mosaic virus;the transcriptome high-throughput sequencing technologies were used to the preliminary study of the color generation mechanism;analyzing gene expression difference and the metabolic pathway of synthetic condition.The research content and results mainly include the following respects:1.Small RNA high-through sequencing technologies were used to build the small RNA libraries of the leaf blade.Then,through bioinformatics analysis,the 276 viral sequences which were preliminary identified were got.By comparing with the virus database,they have homology with Groundnut bud necroshs virus(GB NV)?Watermelon silver mottle virus(WSMV)?Tomato chlorosis virus(ToCV)?Capsicum chlorosis virus(CaCV)and Southern tomato virus(STV)respectively.Virus specific primers were used as the primer to proceed the RT-PCR and the validation results showed that by BLAST comparative analysis,the mosaic virus of C.reticulata is not the detected virus,and it need further research.2.The transcriptome high-throughput sequencing technologies were used to construct cDNA libraries of RNA from the green leaves and the mosaic respectively.By sequencing,assembly splicing and quality testing,the Mapped Reads of the green leaves and the mosaic are 21,079,024 Unigene and 18,332,867 Unigene respectively.Through the analysis of gene expression in the green leaves and the mosaic,a total of 4851 genes are differentially expressed.Noting in the GOG?GO?KEGG?KOG?Pfam?Swiss-part and NR database,the number of genes that were annotated were 1826?2291?1302?2356?2356?2948?2610 and 3969 respectively.From the three aspects,the composition,the metabolism and the biological process to do the functional annotation and the enrichment analysis of the differential expressed genes,a large number of genes on the growth and metabolism of the C.reticulata were obtained.The differential expression genes were analyzed by direct homology,and the results showed that the 25 functional categories were obtained.The enrichment analysis was used to analyze the expression pathways of differential genes,131 metabolic pathways were found been enriched,and among them,3 were relative with the coloring mechanism.3.Based on the sequencing analysis of the transcriptional group,the porphyrin and chlorophyll metabolism,the carotenoid biosynthesis and the flavonoid biosynthesis are included in the related pathways of leaf color synthesis.The analysis shows that the biosynthesis of chlorophyll and carotenoid is hindered,compared with the green leaves,the ratio of two falls 4.67 times.The anthocyanin synthesis gene,the chalcone synthesis gene and other genes which are associated with the biosynthesis of flavonoid are differentially expressed,resulting in the inhibition of pigment synthesis.Analyzing the three ways,it reveals that the virus hinders the formation of the leaf color synthesis and then results in the macular region of the blade which provides the theoretical basis for the cultivation of the colorful C.reticulata.