Effect And Mechanism Analysis Of Feeding On Different Parts Of Wheat Seedling On The Aphid Production Of Rhopalosiphum Padi

Rhopalosiphum padi(R.paid)can reduce the yield and quality of wheat.The control methods relying on chemical pesticides are greatly restricted due to the problems of insect resistance,environmental pollution and natural enemies.Therefore,the research and development of new prevention and control technology is imminent.The niche of R.paid is different from that of other wheat aphids,mainly distributed on the stem and basal leaf of stem.The research group verified its distribution in the early stage.On this basis,the differences of R.paid production after feeding on the stems and leaves of wheat seedlings were studied.In addition,the differences of feeding behavior and nutrients of R.paid on different parts of wheat seedling and their relationship with aphid yield were explored.At the same time,the differentially expressed α-glucosidase gene was obtained based on transcriptome sequencing.And the gene expression and enzyme activity of R.paid were analyzed.Based on metabonomic sequencing,α-glucosidase inhibitors were screened from wheat seedling metabolites to further study the effects of α-glucosidase inhibitors onα-glucosidase and aphid yield of R.paid.The results provide a theoretical basis for the development of new control technology.The results showed that:1.The aphid yield of R.paid was affected by different parts of wheat seedlingThe yield of R.paid after feeding on the stems and leaves of wheat seedlings was observed.It was found that the aphid production of R.paid increased significantly after feeding on the stem of wheat seedling.The total aphid production per aphid was 71 ± 20.The aphid production of R.paid decreased significantly after feeding on wheat seedling leaves.The total aphid production per aphid was 55 ± 15.In addition,the R.paid feeding on different parts of wheat seedling had a great influence on the aphid production period and weight.The period of aphid production was shorter and the body was heavier after feeding on wheat seedling stem.2.Analysis on main factors affecting aphid yield of R.paidDetection of the feeding behavior of R.paid on the stems and leaves of wheat seedlings by the technique of electrical potential mapping.The results showed that the duration of E1 wave on stem and leaf was 15 and 45 min,respectively.The results showed that the saliva secretion time of R.paid on leaves was longer.The duration of E2 wave on stem and leaf was 267 min and 103 min respectively,which indicated that the R.paid had longer feeding time on stem.R.paid may absorb more nutrients on the stem.Further detection of nutritional components in R.paid.It was found that the content of total sugar and glucose in wheat seedling increased significantly after R.paid feeding on the stem of wheat seedling.3.Screening and identification of related genes of sugar metabolism based on transcriptional dataRNA-seq technique was used to analyze the transcriptome of R.paid feeding on different parts of wheat seedlings.The control group was R.paid,which fed on the stem of wheat seedling.A total of 140 differentially expressed genes were obtained,including 100up-regulated genes and 40 down regulated genes.Two α-glucosidase genes were up-regulated.The expression level of α-glucosidase gene in R.paid was verified by q RT-PCR.The results showed that the expression of α-glucosidase gene g25847 and g25848 were up-regulated by 2.8 and 7.3 times respectively,which was consistent with the result of transcriptome sequencing.4.Analysis of α-glucosidase gene expression and enzyme activityDetection of temporal and spatial expression of α-glucosidase gene in R.paid by q RT-PCR.The results showed that the gene was expressed in the whole growth stage of R.paid.From the 2nd instar,the expression level decreased with the development of R.paid.Which indicated that more α-glucosidase genes were needed to participate in the early development of R.paid.The expression level of α-glucosidase gene in the thorax of R.paid is the highest,and its role in the thorax of R.paid remains to be studied.Meanwhile,the α-glucosidase activity of R.paid fed on different parts of wheat seedling was detected.The α-glucosidase activity of R.paid fed on the stems of wheat seedlings was 1.46 times higher than that of the leaves.Which has an impact on glucose metabolism.5.Screening of α-glucosidase inhibitors based on metabonomic analysis of Wheat SeedlingsAcarbose,an α-glucosidase inhibitor,was screened after analyzing the metabolomic data of wheat seedlings.The content of acarbose in the leaves of wheat seedlings was 1.6 times higher than that in the stems.Acarbose in wheat seedling may affect the activity ofα-glucosidase in R.paid.Therefore,acarbose was selected to inhibit the activity ofα-glucosidase for subsequent experiments.6.Effects of acarbose on α-glucosidase and yield of R.paidAfter acarbose treatment,α-glucosidase activity of R.paid decreased by 57%.The expression levels of α-glucosidase gene g25847 and g25848 were significantly up-regulated.The increases were 2.3 and 5.3 times,respectively.The changes ofα-glucosidase activity and gene expression were basically consistent with those of R.paid feeding on different parts.However,it has no effect on the total sugar,glucose content and aphid yield.There may be other metabolic pathways to produce glucose,so that the glucose content remains unchanged,resulting in no change in aphid yield.