Morphological,Physiological,Biochemical And Molecular Responses Of Tea(Camellia Sinensis) Leaves To Tea Green Leafhopper(E.(M.) Onukii Infestation)

Emporasca(Matsumurasca)onukii Matsuda is one of the major pests in tea production areas in China and East Asia and often causes significant losses in tea production.The resistance of tea plants to the infection of tea green leafhoppers has been the focus of research.The defensive response of the tea is generally induced by two evoked factors produced in the feeding of tea green leafhoppers: mechanical damage and infestation by the tea green leafhoppers.In this paper,we took Jinxuan as the research material to compare the morphological,physiological and biochemical characteristics of leafhopper infestation,mechanical damage,and untreated control leaves.Using transcriptome sequencing as a means to diversify and compare the different transcriptomes,we investigated the defense response mechanism of tea green leafhopper infection,the main research results are as follows:1.The weight of tea fresh leaves is reduced by leafhoppers' infestation,and the length of leaves is shortened.The infection of leafhoppers inhibits the growth and development of tea plants and the accumulation of organic matter.The total amount of amino acids,tea polyphenols,and catechins decreased,and the total amount of caffeine slightly increased.The total amount of soluble sugars did not change significantly.2.The activities of PAL enzyme and PPO enzyme of fresh tea leaves were significantly decreased after leafhopper infestation and mechanical injury,which was in some agreement with the results of KEGG metabolic pathway.The leafhopper invasion process and mechanical injury process inhibited the activity of PAL enzyme and PPO enzyme,inhibited some of the tea tree metabolic process,and weakened the tea tree's resistance to stress.3.Compared with the untreated control group,the gene expression levels of the leafhopper infestation process and mechanical injury process were similar,and the difference was not obvious.A total of 31218 differential genes were found in the leafhopper infestation group compared with the untreated control group,of which the differential gene was upregulated by 1361 and the down-regulated expression was 1536.The mechanical injury group was compared with the untreated control group.A total of 31,224 differential genes were found,among which 1592 genes were differentially up-regulated and 1698 were downregulated.The number of differential genes found in the leafhopper infestation group was 31,044 compared with the mechanical injury group.The number of up-regulated expression was 8 and the number of genes down-regulated was 39.4.GO enrichment analysis of the annotation function of differentially expressed genes up-or down-regulates the functional enrichment and functionalization of cells,substance binding and synthesis,and enrichment of cellular components on organelles and cell membranes.,The biochemical process is enriched in cell metabolism and stress response,revealing that the catalytic and synthetic functions on the cell membrane and the changes in the metabolic processes on the membrane are important parts of the tea tree in response to the leafhopper infestation mechanism;the function of mechanical damage is enriched in Leafhoppers have similar infestations,but the number is greater.The catalytic,synthetic functions and metabolic processes on the membrane should be more clearly defined.Mechanical damage is an important cause of the defense mechanism of tea.5.Through KEGG enrichment analysis of the annotation function of differentially expressed genes up-or down-regulated,it was found that the expression of genes in phytohormones synthesis and signal transduction pathways after leafhopper infestation was significantly changed;mechanical hormone synthesis and vitamin metabolism after plant injury The gene expression on the signal transduction pathway changed significantly.It shows that hormonal regulation is an important means of tea tree defense.