摘要: Conopomorpha sinensisis the dominant borer pest ofLitchi chinensis(litchi) andEuphoria longan(longan) in China. Control ofC. sinensisis difficult because of its cryptic life habit; thus, an effective ovicide could be beneficial. The larvicidal effects of diflubenzuron (DFB) have been documented in many insect pest species. Therefore, DFB might be a useful ovicide to controlC. sinensis. However, the detailed mode of action of DFB interference with insect molting and egg hatching is unclear. Thus, we studied alterations in expression of all genes potentially affected by DFB treatment using a transcriptome approach in 2-d-oldC. sinensiseggs. Clean reads were assembled to generate 203 455 unigenes and 440 558 transcripts. A total of 4625 differently expressed genes, which included 2670 up-regulated and 1955 down-regulated unigenes, were identified. Chitin binding and chitin metabolic processes were among the most significant enriched pathways according to Gene Ontology analyses. Most of the genes that encode enzymes involved in the chitin biosynthesis pathway were unaffected, whereas genes that presumably encode cuticle proteins were up-regulated. Furthermore, altered expression patterns of 10 genes involved in the chitin biosynthesis pathway ofC. sinensisembryos were observed in response to DFB treatment at different time points by quantitative reverse transcription polymerase chain reaction. We also observed abnormal development; there was reduced chitin content and modulated chitin distribution of newly hatched larvae, and altered egg hatching. Our findings illustrate an ovicidal effect of DFB onC. sinensis, and reveal more molecular consequences of DFB treatment on insects.

摘要: Sex pheromones serve a critical role in Lepidopterans finding mates. Male moths perceive and react to sex pheromones emitted by conspecific females through a delicate pheromone communication system. Pheromone receptors (PRs) are the key sensory elements at the beginning of that process. The codling moth (Cydia pomnonella) is an important pome fruit pest globally and a serious invasive species in China. Pheromone-based techniques have been used successfully in monitoring and controlling this species. We conducted ribonucleic acid sequencing analysis of the codling moth antennal transcriptome and identified 66 odorant receptors (ORs) in a population from Xinjiang province, China, of which 14 were PRs, including two novel PRs (CpomOR2e and CpomOR73). Four PRs that contain full-length open reading frames (CpomOR1, OR2a, OR5, OR7) and four PRs with ligands that have not been reported previously (CpomOR1, OR2a, OR5, OR7) were selected to deorphanize in the heterologousXenopus oocyteexpression system. Specifically, we found that CpomOR2a and CpomOR5 responded to (E,E)-8, 10-dodecadien-1-yl acetate (codlemone acetate). Furthermore, CpomOR5 (EC50= 1.379 x 10(-8)mol/L) was much more sensitive to codlemone acetate than CpomOR2a (EC50= 1.663 x 10(-6)mol/L). Since codlemone acetate is an important component ofC. pomonellasex pheromone, our results improve the current understanding of pheromone communication in codling moths and will be helpful for the development of pest management strategies.

摘要: The coloration and hatchability of insect eggs can affect individual and population survival. However, few genetic loci have been documented to affect both traits, and the genes involved in regulating these two traits are unclear. The silkworm recessive mutantre(l)shows both red egg color and embryo mortality. We studied the molecular basis of there(l)phenotype formation. Through genetic analysis, gene screening and sequencing, we found that two closely linked genes,BGIBMGA003497(Bm-re) andBGIBMGA003697(BmSema1a), control egg color and embryo mortality, respectively. Six base pairs of theBm-regene are deleted in its open reading frame, andBmSema1ais expressed at abnormally low levels in mutantre(l).BmSema1agene function verification was performed using RNA interference and clustered randomly interspersed palindromic repeats (CRISPR)/CRISPR-associate protein 9. Deficiency of theBmSema1agene can cause the death of silkworm embryos. This study revealed the molecular basis of silkwormre(l)mutant formation and indicated that theSema1agene is essential for insect embryo development.

摘要: Insect neuropeptides regulate various physiological processes, such as reproduction, feeding, growth and development, and have been considered as viable targets in the development of alternative strategies for pest control. Amongst these neuropeptides is myosuppressin (MS), a very conserved neuropeptide that has been reported to regulate cardiac and skeletal muscle contractility, feeding and pupal diapause in insects. In this study, we investigated the involvement of MS in fecundity in a notorious defoliator of potato and other solanaceous plants, the Colorado potato beetle (CPB), Leptinotarsa decemlineata. We identified an MS-precursor-encoding transcript in theL. decemlineatatranscriptomic database and then evaluated its transcript levels in various CPB tissues. MS transcript levels were found to be highest in the central nervous system, gut and muscle of CPB males and females. To investigate the role of MS in fecundity, MS was silenced in adult CPBs through RNA interference (RNAi). This resulted in a significant reduction in oviposition (over 80%) and oocyte size (69%) in the treated beetles compared to the controls. Also, the reduction in oviposition in treated females was confirmed to be dependent on MS knockdown and independent of male fertilization. Furthermore, MS-knockdown in females resulted in decreased levels of ecdysteroid hormone titers and the transcript levels of its receptor. Interestingly, the injection of 20-hydroxyecdysone into females following MS knockdown could rescue ovary development. Altogether, this study highlights the important role played by MS in regulating fecundity in CPB.

摘要: Chemosensory systems are considered to play an important role in host plant selection in herbivorous insects. However, few studies have focused on chemosensory proteins (CSPs) for aphid host-location mechanisms. The roles of CSPs in searching for different Poaceae species (wheat, barley, triticale, maize and sorghum) were tested inRhopalosiphum padi, an important cereal pest. The olfactometer assays showed thatR. padiresponds to plant odors. SevenR. padi CSPgenes were identified. Influence of aphid morph, tissue and starvation state on expression patterns ofCSPswas evaluated. Expression levels ofCSP1,CSP4,CSP5andCSP6in winged aphids were significantly higher than those in wingless ones. Transcription levels of four genes (CSP1,CSP4,CSP5andCSP6) were relatively higher in the head with antennae, and the four genes tended to be upregulated following starvation. Silencing of threeCSPs (CSP4,CSP5andCSP6) altered aphid host-location behavior in response to the five different host plants tested. Three volatile compounds of host plants (octanal, [E]-2-hexenol and linalool) have significant attraction to wingedR. padiaccording to the four-arm olfactometer tests. Molecular docking predicted hydrogen bonding sites which played key roles in the binding of CSP4, CSP5 and CSP6 with volatile compounds. Knockdown ofCSP4orCSP5significantly decreased the staying time ofR. padiin the arms with octanal. However, knockdown ofCSP6could not affect the response ofR. padito octanal. These results bring evidence for the involvement of three CSPs inR. padihost-location behavior.