Molecular Strategies Of Wing Plasticity Development And Its Trade-off Regulation In Brown Planthopper,Nilaparvata Lugens

Wing-polymorphism is an important manifestation of insect phenotypic plasticity.The brown planthopper(Nilaparvata lugens),exhibit obvious wing dimorphism which have the macropterous and brachypterous dispersal morphs.The macropterous brown planthopper can fly long distances with fully developed wings and indirect flight muscles,which is helpful for population diffusion.But the brachypterous planthopper has stronger reproductive capacity,which is conducive to the rapid reproduction of the population in the habitat.Therefore,the nymphs of the brown planthopper must make a trade-off between dispersal and reproduction before the adult eclosion according to the changes of external environmental conditions,which is beneficial for the continuation of the population.Although many researches have revealed the tradeoff mechanism between tissue plasticity development and reproductive and other life characteristics based on the insects such as Orthoptera,Coleoptera and Hemiptera,the molecular mechanism of its occurrence has been rarely reported up to now.This article around the regulation function of insulin signaling pathway by using the methods of comparing the transcriptome data,gene silence.The gene sequential expression pattern of whole genome level about long and short wings of BPH were analyzed from the egg to the adult,the molecular mechanism of trade-off about plasticity development fore/hind-wing plasticity and reproduction between growth and physiological and biochemical process.The main research results are as follows:(1)Insulin-mediated tradeoff regulation strategy of wing-polymorphism and physiological and biochemical processes.Cuticle protein(cuticle protein),CP gene significantly expressed lower in Nl In R2^E4a-/-mutant larva stage,in addition,the genes regulating the carbohydrate metabolism(serine,arginine and proline metabolism)and lipid metabolism(glycerides/glycerol phospholipid metabolism and cutin,undersea lipid biosynthesis and wax)and glycolysis/sugar dysplasia genes also significantly expressed lower in larva stage.The expression of Nlvestigial in adult stage was significantly up-regulated.The expression of Nl Flightin and Tpn C4 were significantly upregulated,and Nlvitellogenin was downregulated in female adults silenced by ds NlFoxO.Therefore,the long-winged brown planthopper may provide energy for wing development by decreasing the metabolic rate during the nymphal stage,while the differential genes are related to migratory movement in the adult stage.(2)Fox O regulates the development of wing plasticity by regulating the span of cell proliferation.Comparative transcriptome analysis showed that a large number of genes(10-19%)were differentially expressed in the forewing buds and hindwing buds of the fifth-instar brown planthopper,including cell cycle related genes(e.g.cyclin D2).GO enrichment analysis showed that the differentially expressed genes were mainly related to cell process,binding and cell part classification.KEGG analysis showed that the up-regulated differential genes were significantly enriched in DNA Replication and Cell Cycle pathways.Therefore,silencing NlFoxO may upregulate the level and duration of genes expression related to cell proliferation,which may be the main driver of long wing development.(3)Insulin signaling pathway regulates the reproductive plasticity of brown planthopper by mediating methylation.We identified Nl MTase15,an important methyltransferase for ovary development of female brown planthopper.The silencing of Nl MTase15(ds Nl MTase15)resulted in insufficient production of female adults.In addition,male adults silenced by ds Nl MTase15 retain sperm that produced normal motility,but fewer sperm were transferred to wild-type females and the eggs diapause at embryonic stage.The results provide direct evidence that insulin signaling may regulate reproductive plasticity by regulating epigenetic pathways.This study first analysis the insulin pathway leading long wings BPH and short wings BPH from egg to adult gene expression in the whole development period from the point of view of whole genome system,the results provide a theoretical basis for the molecular strategy of trade-off about the plasticity of wing development and physiological and biochemical process.