| The white-backed planthopper,Sogatella furcifera,is a typical sap-sucking insect that causes considerable damage on rice by sucking phloem sap and transmitting plant viral diseases.S.furcifera secretes watery and gelling saliva during feeding.The saliva includes bioactive compounds that have a range of functions from degrading plant cell and digesting nutrients to eliciting or inhibiting plant defense.Proteomic analysis of sap-sucking insect saliva is a useful method to discover the salivary proteins that play important roles in feeding and virulence.Therefore,in this study,we analysed the proteome of watery saliva secreted by S.furcifera,verified the sequences of secretory proteins,investigated the expression level of salivary genes and interfered the mucin-like protein(Mucin).We identidfied the salivary components to enrich the database of S.furcifera salivary protein.As for Mucin,which was specifically expressed in salivary gland,we investigated its function in feeding,laying the foundation for management of S.furcifera.The results are as follows:1.Proteomic analysis of watery saliva secreted by S.furcifera.We collected the watery saliva of S.furcifera by feeding with surcrose solution and identified the major proteins in watery saliva of S.furcifera by shotgun LC-MS/MS analysis combined with transcriptomic analysis.A total of 161 proteins were identified,which were divided into 8 function categories,including enzymes,transporter,calcium ion binding protein,salivary sheath protein,cytoskeleton protein,DNA-,RNA-,and protein-binding or regulating proteins,other non-enzyme proteins and unknown proteins.2.Sequence cloning and expression pattern of salivary protein secreted by S.furcifera.We chose 11 secretory protein genes that play roles in feeding and virulence and verified the nucleotide sequences by cloning and sequencing.We conducted the real-time qRCR to investigate the tissue-,developmental stageand sex-specific expression patterns of S.furcifera secretory protein genes.We detected that Mucin had a unique expression level in salivary gland.In addition,the expression level of this gene was increasing with the development of S.furcifera.This suggests that Mucin plays an important role in feeding.3.RNA interference of Mucin.We silenced the Mucin,which is specifically expressed in salivary gland,to detect the effects on survival rates,feeding consumption,feeding behavior,morphology of salivary gland and salivary sheath.The results showed that silencing of Mucin significantly decreased the feeding consumption of S.furcifera and made it difficult to suck phloem sap,which decreased the survival rates of S.furcifera feeding on rice.Knocking down of Mucin influenced the formation of A-follicle in salivary gland and resulted in the secretion of short and single-branched salivary sheaths.Moreover,silencing of Mucin led to less salivary flange on rice.As a result,Muicn is involved in the formation of salivary gland and salivary sheath and it plays an essential role in feeding process of S.furcifera. |
PDF Full Text Request