Metabolomics Mechanisms Underlying Inhibition Of Infestatiion By Toxoptera Aurantii On Defense Response Of Tea Plants To Ectropis Obliqua

Plants are commonly attacked by multiple herbivorous species.The loss of plant tissue and nutrient caused by the feeding of herbivorous will inevitably lead to changes in metabolites,and then have an important effect on the insect resistance of plants.Camellia sinensis is an important economic crop in our country,which can be damaged by more than 40 kinds of pests in natural conditions.Toxoptera aurantii and Ectropis obliqua are important pests that occur frequently and seriously in C.sinensis,and can occur simultaneously in the same plant in natural conditions.Preliminary study results show that compared with the control,feeding on the plant that have been harmed by T.aurantii six days can significantly benefit to E.obliqua's growth,but feeding on the plant that have been harmed by T.aurantii two days have no significant change in E.obliqua's growth.Basing on the present research progress of both at home and abroad,and combining our previous results,the second leaf of C.sinensis were chosen as the research subjects.To analyze the difference of metabolites in T.aurantii infection leaves and infection by different mouthparts leaves,the GC-MS and HPLC was used to analysis.Principle component analysis(PCA)and orthogonal partial least-squares-discriminant analysis OPLS-DA were performed to visualize the metabolic difference among experimental groups,after mean centering and unit variance scaling.And then tested the effect of rutin on the growth and development of E.obliqua in vitro.The main results are as follows:(1)The inhibition effect of T.aurantii on cellular respiration of C.sinensis was determined.After T.aurantii infection 6 d,the content of glucose 1-phosphate glucose,glucose 6-phosphate,fructose 6 – phosphate,citric acid,isoccitric acid,malic acid and fumaric acid have been significant reduced.Sucrose,a synthetic product of photosynthesis,was significantly accumulated.However,only fructose 6-phosphate was significantly decreased after T.aurantii infection 2 d.By inhibiting the cellular respiration of tea leaves,reduced the material and energy supply of the synthesis of secondary metabolites.(2)Infection by T.aurantii inhibit the synthesis of C.sinensis secondary metabolites.After T.aurantii infection 6 d,the content of shikimic acid,4-hydroxy cinnamic acid,chlorogenic acid,gallic acid,twist and putrescine were significantly lower than control.However,there is no significant change after T.aurantii infection 2 d.(3)Infection by T.aurantii have significantly affect on the content of various free amino acids.After T.aurantii infection 2 d,the content of proline,tyrosine,L-hydroxy proline and gamma aminobutyric acid was significantly raised.While,the content of L-hydroxyproline was significantly reduced,proline and tyrosine were not significantly changed in leaves after infection 6 d.These amino acids are widely reported related to plants defensive response,those change may improve the resistance of tea leaves to aphids.On the orther hand,the content of threonine and serine are significant indused by T.aurantii infection both 2 d and 6 d,this may benefit to E.obliqua.(4)Infestation of E.obliqua enhances the response of catechin metabolism in C.sinensis.E.obliqua infested C.sinensis significantly induced the expression of Cs ANR within 3 h?6 h?12 h,and very significantly induced within 3 h.E.obliqua infested tea plants also significantly induced the expression of Cs LAR within 6 h?12 h.Moreover,the content of C?EGCG?ECG?GC were significantly higher than control.(5)Rutin is make for growth ang development of E.obliquaAfter infection 48 h,compared to the control,the content of rutin is up-regulate 57% in T.aurantii infected leaves,and down-regulate 35% in E.obliqua infected leaves.While the content of rutin in composite infected leaves is up-regulate 62% than it in E.obliqua infected leaves.Further study indicated that rutin is make for growth ang development of E.obliqua.This article studied the relationship between different herbivore in one plant.Infected by T.aurantii significantly increased the content of sucrose and amino acid and decreased the content of secondary metabolites.The anti-insect target compounds can be found in those compounds that can provide theoretical basis for the green control of C.sinensis.