Study On The Specific Secondary Metabolism In Tea Based On The Transcriptome And Metabolome Analysis In Grafted Seedlings Of Camellia Sinensis And Camellia Oleifera

Camellia sinensis and Camellia oleifera are perennial woody plants,both belong to Theaceae Camellia.The accumulation of the metabolites and gene expression patterns were quite different from each other.In order to clarify the mechanism of the accumulation and biosynthesis of tea specific secondary metabolites,and the key genes regulate the pathways of characteristic secondary metabolism,the grafted seedlings of Camellia sinensis and Camellia oleifera as rootstocks and scions,were respectively cultivated and studied,and the self-grafted seedlings of Camellia sinensis and Camellia oleifera were established as controls.The transcriptome and metabolome of leaves and roots in the grafted seedlings were analyzed,and the information of differential patterns of genes and metabolites were obtained.Moreover,the association analysis of the secondary metabolic pathways was carried out,and the RNA-seq from the transcriptome were verified by q RT-PCR.The contents of secondary metabolites of different parts in roots,stems and leaves of the two-year-old tea grafted seedlings were analyzed,and used for explaining the stable characters in the grafted tea plants.The study was based on the transcriptome and metabolome analysis of the spefic secondary metabolism using the grafed seedlings of Camellia sinensis and Camellia oleifera,the main results were shown as follows:1.In this study,eight high-quality c DNA libraries of leaves and roots of four kinds Camellia sinensis and Camellia oleifera grafts were constructed by High-Throughput Sequencing.48.72 Gb clean data were obtained with an average data of 6.09 Gb.The Unigenes of 96,417,84,636 were obtained from leaves and roots of Camellia sinensis and Camellia oleifera,respectively.The functional annotation genes accounted for 71%,72.37% in the total Unigenes.2.1375 Unigenes were up-regulated in the leaves of the grafted seedling of CS-CO,compared with the control seedlings of CS-CS,which siginicantly enriched in the pathways of flavonoids biosynthesis,GSH metabolism,limonene and pinene degradation,tyrosine metabolism,styrene compounds,diary heptane and ginger hydroxybenzene biosynthesis,glycolysis/glucose production,half terpene and terpene biosynthesis.However,2437 Unigenes were down-regulated,which siginicantly enriched in the pathways of the nitrogen metabolsim,proteoglycan degradation,terpenoids skeleton biosynthesis,indole alkaloids biosynthesis.3.The OPLS-DA models established for 7230,3223 peaks of mass spectra were obtained in the positive and negative modes by LC-MS detection.22 kinds of differential metabolites were screened and identified from the leaves of the grafted seedlings of CS-CO compared with the control CS-CS.Among them,the accumulations of theanine and caffeine decreased significantly,while the amount of flavonoids apparently increased.4.HPLC analysis showed that the content of total free amino acids in the leaves of two-year-old grafted seedlings CS-CO was lower than that of CS-CS,while there was no significant difference in the content of the leaves of two-year-old grafted seedlings CO-CO.The content of amino acids in grafted tea leaves was significantly affected by rootstocks.However,the amounts of caffeine and catechins in the leaves of two-year-old grafted seedlings CS-CO were closely similar to the leaves of the control seedlings(CS-CS).It showed the accumulations of caffeine and catechins were significantly affected by their scions.