Difference Study Between Dachang Tea And Tufang Tea Based On Transcriptome And Metabolome Analysis

Tea,originated in China,is one of the three major non-alcoholic beverages in the world,rich in tea polyphenols,alkaloids,amino acids,tea polysaccharides and other physiologically active ingredients.Catechin is the main component of tea polyphenols,and it is also an important component that determines the quality and function of tea.The catechins in tea are divided into phenotypic catechins and non-phenotypic catechins,and their content and monomer composition in tea plants are related to the resources of tea species.In order to explore the composition characteristics and molecular mechanism of catechins from different tea resources,this study used the Dachang tea and the rare tea resource Tufang tea as materials,the content and composition of catechins in Dachang tea and Tufang tea fresh leaves,Dachang tea and Tufang tea were determined by LC-MS comparative analysis.The characteristics of the metabolome composition in the tissue were analyzed,the transcriptional profiles of Dachang tea and Tufang tea were compared and analyzed by high-throughput sequencing technology,and the expression differences of the corresponding genes of some key enzymes in catechin biosynthesis in the materials were studied.The main results are as follows:1)The content of catechins in tea leaves is explained by measuring: the contents of epicatechin gallate（ECG）and epicatechin gallate（EGCG）in Tufang tea are the most,accounting for 31.3% and 30.2% respectively,followed by Gallic catechin（GC）9%;Epicatechin gallate（ECG）is the highest in the catechin content of Dachang tea,which is significantly higher than that of other catechins.2)Metabolomics assay showed that a total of 1113 metabolites were detected in different samples.Compared with the leaf tissue metabolites of Dachang tea and Tufang tea,the cluster heat map and volcano map of differential metabolites in positive ion mode showed that they have different metabolic characteristics,and the former was more up-regulated than the latter in positive ion mode.There are 79 species,127 species are down-regulated,and 907 are unchanged metabolites;the cluster heat map and volcano map of differential metabolites in negative ion mode show that they have different metabolic characteristics,and the former is more than the latter in negative ion mode.29 were up-regulated,87 were down-regulated,and 423 were unchanged metabolites.3)In the positive ion mode,KEGG analysis was performed on these differential metabolites obtained in this study,and cluster Profiler was used to select the hypergeometric test method to perform enrichment analysis on the annotation results of the differential metabolites KEGG.There are 14 metabolic pathways involved,accounting for 6.8 %;The analysis process is the same in negative ion mode.KEGG analysis was carried out on the differential metabolites,and the annotation results of the differential metabolites KEGG were enriched and analyzed by using the method of hypergeometric test selected by clusterprofiler.There were 47 metabolic pathways involved,accounting for 40.52%.4)Transcriptomics analysis showed that 84,322 Transcripts and 37,842 Unigenes were assembled by related software.The N50 lengths of Transcripts and Unigenes were1799 bp and 1784 bp,and the average lengths were 1329.96 bp and 1222.55 bp,respectively.The assembly integrity of the obtained fragments is high.For the Unigenes obtained in this study,there were 27,470 functional annotations,of which up to 26,927 were matched to the Nr database,while the least number of genes annotated to the COG database was only 7,009.5)According to the FPKM expression abundance information of Dachang tea and Tufang tea leaf tissues,with FDR ≤ 0.01 and |log2FC| ≥ 1 as the standard,the differentially expressed genes shown in Table 3-7 were obtained.There were 1746 differentially expressed genes in Tufang tea leaf tissue.Compared with Tufang tea leaf tissue,917 unigenes were up-regulated and 829 down-regulated in Dachang tea.