Font Size: a A A

Identification, Expression And Functional Analysis Of Odorant Receptors In Green Plant Bug Apolygus Lucorum(Meyer-DR)

Posted on:2020-09-24Degree:DoctorType:Dissertation
Country:ChinaCandidate:X K AnFull Text:PDF
GTID:1363330572498876Subject:Agricultural Entomology and Pest Control
Abstract/Summary:PDF Full Text Request
With successful promotion and cultivation of Bacillus thuringiensis(Bt)cotton,the regional population of Apolygus lucorum in cotton fields has increased dramatically,causing huge economic losses to the production of cotton and various other economic crops.It has proven that A.lucorum has a sensitive olfactory system to accurately locate the host plant and continue to transfer to new host plants.In addition,the male can accurately locate the female via the sex pheromone secreted by the female and complete the mating behavior.At the molecular level,multiple proteins are involved in this process,such as odorant binding proteins(OBPs),chemosensory proteins(CSPs),odorant receptors(ORs),ionotropic receptors(IRs),and sensory neuron membrane proteins(SNMPs).The specific functions of these proteins are hotspots of insect chemosensation research.Here,some olfactory genes from A.lucorum were identified and their functions were also checked.We performed a transcriptome analysis of both female and male antennae,and a total of 110 OR genes from A.lucorum were identified and named,among which 46 sequences encoded a full-length open reading frame(ORF)and AlucOrco is the most abundant gene.The semi-quantitative RT-PCR of the four tissues showed that two AlucOR genes were specifically expressed in the female antennae and two AlucOR genes in the male antennae.Ten AlucORs were highly expressed in the female antennae,and 18 AlucORs were highly expressed in the male antennae.The qPCR showed that 40 AlucORs genes were highly expressed in the antennae(5 times higher than that in other body parts),and AlucOR91 was 7.4 times higher expressed in female antenna than in other tissues,and 9 AlucORs were higher expressed in male antennae(5.5~38.1 times higher)than in other tissues.In addition,phylogenetic tree analysis predicted a conserved sex pheromone subclade of A.lucorum.Twenty four new chemosensory related genes were newly identified,including 7 AlucCSPs,6 AlucGRs,7 AlucIRs and 4 AlucSNMPs.Expression profiling revealed that AlucSNMP1 b,AlucCSP14 and AlucIR41 a.2 were highly expressed in the antennae.In addition,four GR genes,AlucGR63 a,AlucGR66a,AlucGR66 b,and AlucIR41 a.3 were highly expressed in the stylet and higher in the male stylet.Three genes,AlucOR4,AlucOR40,and AlucOR59 were selected from the conserved sex pheromone subclade.The two-electrode voltage clamp was used to verify their potential ligands.The results showed that AlucOR4 has response to two sex pheromone components hexyl butyrate(HB)and(E)-2-hexenyl butyrate(E2HB)with greater response to E2 HB.AlucOR40 showed response to hexyl hexanoate,(Z)-3-hexenyl hexanoate,amyl butyrate,ethyl caprylate,and with biggest response to hexyl hexanoate.AlucOR59 showed response to E2 HB,ethyl caprylate,n-octyl acetate,and n-octyl butyrate with the biggest response to E2 HB.The ligands are belong to sex pheromones or analogs,which prove that these three genes are all sex pheromone receptors.We selected to knockdown AlucOR4 to check its involvement in the pheromone reception via RNAi.EAG results showed that antennae responses to the two pheromones decreased by 38%~44%,In addition,the tendency to sex pheromone lures of male bugs impaired after AlucOR4 silenced by RNAi.The voltage-clamp was used to verify the ligands of AlucOR91 and AlucOR21 which are highly expressed in female and male antenna,respectively.AlucOR91 showed responses to(-)-terpinen-4-ol,1-undecanol,1-dodecanol,1-pentadecanol,and dl-Isoborneol with the biggest response to dl-Isoborneol.However,AlucOR21 didn't show response to any odorants.AlucOR91 may be involved in the location of to located host plants and oviposition sites.
Keywords/Search Tags:Apolygus lucorum, Transcriptome, Chemosensory genes, Odorant receptor, Pheromone
PDF Full Text Request
Related items