Screening And Differential Expression Analysis Of Genes Related To Anthocyanin Biosynthesis In Purple Buds Of Tea(Camellia Sinensis)

Anthocyanins are water-soluble pigments which widely exist in plants.As a strong free radical scavenger,it has many health protection functions in anti-inflammatory,anti-oxidation,blood pressure lowering,hypoglycemic effect.The purple-buds tea plants are a kind of excellent tea germplasm rich in anthocyanins.More and more attentions have been focused on research and utilization of purple-buds tea plants.Compared to model plants,the research on the metabolic pathway of anthocyanins in tea started late,its not mature enough.Some of the genes involved in the anthocyanins biosynthesis have been cloning,but the metabolic pathway of anthocyanins in tea is a complex network structure that is affected by multiple metabolic pathways and is completed by a series of enzymes,so further exploration is needed to reveal the mechanism.9803 is a purple-buds cultivar with purple all year round,it is a natural material for studying the synthesis mechanism of anthocyanin.In this study,RNA-seq and bioinformatic analysis was performed in tea plant(purple-buds cultivar 9803 and green-buds cultivar 9806,hunan Agricultural University,changsha,hunan,china),at the transcriptome level,differential genes related to the metabolism of anthocyanins in purple-buds tea plants were screened,which laid the foundation for further revealing the molecular mechanism in purple-buds tea plants.The main results were listed as follows:(1)Through the Illumina HiSeqTM 2000 sequencing platform,6 transcriptome libraries of purple-buds cultivar 9803 and green-buds cultivar 9806 were constructed.A total of 42.83 G of high-quality data was obtained after removing the connector and low-quality reads.(2)By alternative splicing analysis,286 differential AS events were found in the comparison of purple-buds cultivar 9803 and green-buds cultivar 9806,of which 144 differential AS events were up-regulated and 142 were down-regulated in purple-buds cultivar.(3)The SNP and InDel analysis were used to classify the number of sample variation loci,and the chromosomal location of each mutation site,the coordinates of the variation loci,the genotypes before and after the mutationand the amount of expression in each sample were annotated in detail.(4)Through the comparison with the tea plant reference genome,the structure of 18,550 genes in genome was optimized,8681 new genes were obtained,and the function of these genes was predicted.(5)Through gene differential expression analysis,11060 differential genes were screened,among which 5289 genes were significantly up-regulated and 5771 genes were significantly down-regulated in purple-buds cultivar.Through functional enrichment analysis in selected differential genes,42 unigenes are associated with anthocyanin biosynthetic pathway were screened in tea,including 34 genes in the GenBank date base and 8 genes not reported.KEGG pathway analysis showed that differentially expression genes annotated to five metabolic pathways,including flavonoid biosynthetic pathway,lignin biosynthesis pathway,flavone and flavonol biosynthesis pathway,brassinosteroid biosynthesis pathway and encoding transcription factors.