Network-based Analysis Of Wing Dimorphism And Antiviral Immune Responses In Sogatella Furcifera And Construction Of The Pest Genome Database

White-backed planthopper(Sogatella furcifera)is a rice pest not only directly causing damage to rice plants,but also transmitting rice virus and having a strong dispersal capability.Thus,it serves as an ideal model for studying host plant-virus-insect vector interactions and phenotypic plasticity of wing size.In order to investigate the regulatory methanism of wing dimorphism as well as the interaction patterns between S.furcifera and Southern rice black-streaked dwarf virus(SRBSDV),we constructed wing dimorphism and immune response related gene interaction networks.Combined with multi-omics data,including RNA-Seq and ChIP-Seq,the network-based analysis revealed the roles of genes and pathways in wing dimorphic development and antiviral immune response to SRBSDV.We also identified and verified novel regulatory genes in the regulation of wing dimorphism.First,phenotypic plasticity is a common and highly adaptive phenomenon in insects,and the same genotype can produce different phenotypes in response to environmental changes.The wing dimorphism in S.furcifera is one of them.Previous studies have shown that the IIS-PI3K-Akt-FOXO signaling pathway plays a crucial role in the regulation of wing dimorphism in planthoppers.However,other regulatory genes and downstream effectors of the pathway are still not fully explored.Based on transcriptome data,we found that flight muscle genes and energy metabolic genes are highly expressed in the wing hinges of the long-winged morph,and also,flight muscle genes exhibited significant alternative splicing,indicating the powerful flight capabilities and active energy metabolism in the long-winged.Next,based on the FOXO ChIP-Seq data,we predicted 1259 FOXO target genes in the wing hinges,including wing dimorphism,flight muscle and energy metabolism related genes.Then we constructed an integrated gene interaction network combining homology-based protein-protein interactions,co expression interactions,functional associated interactions and FOXO-target gene interactions.The integrated network was divided into densely connected functional modules by MCL clustering.In the ?S-PI3K-Akt-FOXO pathway related module,we identified 45 differentially expressed genes that having direct interactions with the components of this pathway.These 45 genes were regarded as Insulin pathway mediated wing dimorphism related genes(IWDRGs).We selected five genes from them for experimental verification,and found that all the five genes played roles in the regulation of wing size.This study provided valuable insights into the regulation mechanism of wing dimorphism in S.furcifera,and demonstrated that network-based analysis is a potent method for identifying novel regulatory genes.In addition,we constructed an immune-related network in a similar manner by combining multiple heterogeneous interactions.Using transcriptome data of 5.furcifera male and female adults feeding on SRBSDV-infected rice plants,we identified the activated or suppressed immune genes,pathways and network modules in response to SRBSDV infection.The results indicated the potential sexual dimorphism in the antiviral immune response in a series of immune pathways such as RNA interference(RNAi).Endocytosis-related network module exhibited significant expression changes with various viral titres.Moreover,in females,the expression of vitellogenin(Vg)associated with fertility was up-regulated with increasing viral titres,suggesting that SRBSDV may enhance the fecundity of S.furcifera females.Lastly,on the basis of the newly assembled S.furcifera genome and a wealth of multi-omics data produced by our lab,we established a genome database of S.furcifera,which provided a platform for query,visualization and download of genomics data and high-throughput sequencing data,aimed to enrich the research resources of S.furcifera and lay a good foundation for future studies.