Regulating Effects Of Trehalose-6-phyosphate Synthase And Trehalase On The Trehalose And Chitin Metabolism In Acyrthosiphon Pisum Harris

Acyrthosiphon pisum Harris is one of the important world wide agricultural pests,which was worst affected alfalfa,peas,broad beans,clover and so on.In northwest of China,it has caused serious economic losses about 10% to 30% per year due to alfalfa pests,especially aphids.It creates incalculable losses to agricultural production through directly feeding or spreading 25 kinds of plant viruses,such as alfalfa Mosaic virus.In recent years,transgenic technology has been applied in pest control management and it may be an effective strategy in the future.Researching the regulation of trehalose-6-phyosphate synthase(TPS)and trehalase(TRE)on the synthesis and metabolism of trehalose and chitin,it provides a theoretical basis for clarifying the function of trehalose related genes and the regulation mechanism of physiological activities.Trehalose,as the blood sugar,it is also the mian carbohydrate in hemolymph of insects,accounting for 80-90% of total hemolymph sugar.Trehalose is mainly synthesized in the fat body of insect,besides in the gut,blood,ovaries and even in leg muscles through TPS.TPS and trehalase TRE play a key role in the metabolisms of trehalose and chitin.In this study,using RNAi technology,feeding pea aphid with artificial diets containing high concentration(100 mg/m L)trehalose and glucose.The regulation function of trehalose-6-phyosphate synthase and trehalase on trehalose and chitin metabolism of pea aphid were studied.The main results are as follows:1.The survival rate,life table parameters of net reproductive rate and reproduction of A.pisum were decreased after RNAi of Ap TPS and Ap TRE,high trehalose and glucose treatment.RNAi of Ap TRE resulted in two abnormal phenotypes(molting deformities and wing deformities)in the red A.pisum but only one abnormal phenotype(molting deformities)in the green A.pisum.2.Feeding behaviors were changed after treatment by RNAi of Ap TPS and Ap TRE,high trehalose and glucose during 24 h to 48 h,but it was significantly different at 48 h,which the percentage of E2 wave was reduced and the percentage of F wave and G wave was increased.Meanwhile,decreased the feeding time of A.pisum in phloem and increased the feeding time in xylem.The A.pisum regulated negative environment through reducing carbohydrates,increasing water and salt intake.3.RNAi Ap TPS reduced trehalose content in A.pisum,while RNAi Ap TRE could not hydrolyze trehalose which continuously accumulated to increase its content.The hyperglycemic environment lasted for at least 48 h after hyperglycemic feeding.High trehalose content was beneficial to the accumulation of glycogen,while medium and low trehalose content had no significant effect on the accumulation of glycogen.RNAi could reduce TRE activitality.However,TRE1 activitality could be increased by feeding trehalose at100 mg/m L.It was found in Ap TPS expression that hyperglycemia treatment reduced Ap TPS expression.RNAi Ap TRE inhibited Ap TPS expression at 24 h,but promoted its expression at48 h.4.Ap TPS and Ap TRE affected the m RNA expression of related genes in the chitin metabolism pathway.At 24 h,RNAi of Ap TPS and Ap TRE mainly reduced gene expression related to chitin metabolism pathway.However,at 48 h,there were three expression conditions: continuously decreasing,restoring or increasing.There were differences between RNAi of Ap TPS and Ap TRE,as well as between red A.pisum and green A.pisum.5.High trehalose and high glucose can disturb the metabolism of aphid,and also affect the expression level of genes related to the chitin metabolism pathway of A.pisum.As detailed in our findings above,the Ap TPS and Ap TRE have regulated function in trehalose and chitin metabolism.But so far we were unable to clearly address the specific regulatory mechanism.Certainly,it is necessary to the further study to the regulatory mechanism about Ap TPS and Ap TRE on the trehalose and chitin metabolism in Acyrthosiphon pisum Harris.