Identification Of Salivary Protein Components And Preliminary Study On Their Functions In Procecidochares Utilis

Eupatorium adenophorum Spreng is a plant of the Genus Eupatorium in the composite family,which has a strong invasive ability and is a malignant weed.Its perennial characteristics have caused huge economic losses in agriculture and disrupted the local ecological balance in its invasive areas.Procecidochares utilis Stone is a Dipteran insect in the family Procecidochares,and is an important predatory natural enemy of the invasive weed E.adenophorum.Research has found that the fruit fly of P.utilis can effectively inhibit the growth and development of E.adenophorum.Saliva is the main factor that insects exert influence on plants,and it is also an important pathway for plants to perceive different types or ages of insects feeding.The salivary glands of insects play an important role in the interaction between insects and host plants.In this study,the physiological and biochemical responses of E.adenophorum after being induced by salivary gland homogenate of P.utilis were investigated,and the physiological basis of the effect of salivary gland substances of P.utilis larvae on gall formation was preliminarily studied.The salivary protein components of Bactrocera eupatorium larvae were analyzed by label free proteomics;To provide new ideas for the development and utilization of salivary proteins from P.utilis and to reduce the defensive effect of E.adenophorum,in order to find a breakthrough for the effective management of E.adenophorum.The main research findings are as follows:(1)Using Label free quantitative proteomics technology,3485 proteins were identified in the salivary glands of the 1st and 2nd instar larvae of P.utilis,including 3368 quantitative proteins and 3234 proteins shared by the salivary glands of the 1st and 2nd instar larvae.It is predicted that 160 proteins have signal peptide.According to the PFAM domain and KEGG annotation results,155 salivary proteins have been annotated,which can be divided into guessing proteins,peptidase hydrolysate,glycosidase hydrolysate,esterase hydrolysate,oxidoreductase,isomerase,transporter,recognition/binding proteins,specific matrix proteins,enzyme inhibitors,structural proteins,other functional proteins and molecular chaperones.A total of 138 proteins were screened for significant changes in expression levels,of which 90 proteins were significantly upregulated and 48 proteins were significantly downregulated.(2)A total of 81 RING finger proteins were identified from P.utilis by combining genome,transcriptome and proteome.According to the type of domain,they were further divided into two subclasses,namely 48 HC subclasses and 33 H2 subclasses.QPCR analyzed the expression of 15 RNF genes in different tissues of larvae and found that they had high expression levels in salivary glands and long Martensian ducts;At different developmental stages,most genes have high expression levels in female adults,and these genes may play important roles in female adult development and reproductive processes.(3)After treatment with the salivary gland homogenate of the P.utilis,there were significant changes in the nutrient content and protective enzyme activity of the leaves of E.adenophorum.The soluble sugar content and proline content gradually increase with the increase of injection concentration,while chlorophyll a,chlorophyll b,and total chlorophyll content all significantly decrease;The activities of superoxide dismutase,peroxidase and catalase in the leaves of E.adenophorum increased significantly.Research has shown that E.adenophorum exhibits a strong physiological and biochemical response to the saliva homogenate of the fruit fly P.utilis.E.adenophorum responds to the impact of saliva homogenate on its growth and development by altering its physiological characteristics.(4)A total of 294 differentially expressed unigenes genes were screened by high-throughput sequencing in E.adenophorum injected with salivary gland homogenate of P.utilis and phosphate buffer salt.Among these 294 unigenes,266 were upregulated and28 were downregulated.Some differentially expressed genes are associated with the synthesis of zeatin,lignin,etc.