摘要: Spodoptera liturais a destructive agricultural pest in tropical and subtropical areas. Understanding the molecular mechanisms ofS. lituraadaptation to its preferred host plants may help identify target genes useful for pest control. We used high-throughput sequencing to characterize the expression patterns of messenger RNAs (mRNAs) and microRNAs (miRNAs) in the midgut ofS. liturafed onBrassica junceafor 6 h and 48 h. A total of 108 known and 134 novel miRNAs were identified, 29 miRNAs and 237 mRNAs were differentially expressed at 6 h ofB. junceafeeding, 26 miRNAs and 433 mRNAs were differentially expressed at 48 h. For the mRNAs, the up-regulated genes were mostly enriched in detoxification enzymes (cytochrome P450, esterase, glutathioneS-transferase, uridine diphosphate-glucuronosyl transferase), while the down-regulated genes were mostly enriched in proteinases and immune-related genes. Furthermore, most detoxification enzymes begin to up-regulate at 6 h, while most digestion and immune-related genes begin to up- or down-regulate at 48 h. Eighteen and 37 differently expressed transcription factors were identified at 6 h and 48 h, which may regulate the functional genes. We acquired 136 and 41 miRNA versus mRNA pairs at 6 h and 48 h, respectively. Some down-regulated and up-regulated miRNAs were predicted to target detoxification enzymes and proteinases, respectively. Real-time quantitative polymerase chain reaction of nine randomly selected miRNAs and 28 genes confirmed the results of RNA-seq. This analyses of miRNA and mRNA transcriptomes provides useful information about the molecular mechanisms ofS. lituraresponse toB. juncea.

摘要: Cuticular proteins (CPs) are critical components of the insect cuticle and play important roles in maintaining normal insect development and defense against various environmental stresses. The oriental fruit fly (Bactrocera dorsalis) is one of the most destructive pests worldwide, and its eight CPs analogous to peritrophin 3 (BdCPAP3) family genes have been identified in our previous study. In the present study, we further explored the possible roles ofCPAP3genes inB. dorsalisdevelopment. Each sequence ofBdCPAP3genes contained three conserved ChtBD2 (chitin-binding) domains. Spatial and temporal expression patterns revealed that the fourBdCPAP3genes (BdCPAP3-A1,B,E, andE2) might play important roles in larval pupariation ofB. dorsalis. Moreover, treatment with a juvenile hormone analog (methoprene) significantly restricted expression of these four CPAP3 genes, whereas treatment with 20-hydroxy-ecdysone induced expression. The RNA interference (RNAi) results revealed that down-regulatedCPAP3genes led to significant delay of pupariation, and injection of dsBdCPAP3-E into 5-d-oldB. dorsalislarvae caused approximately 40% mortality. Interestingly, we also confirmed thatBdCPAP3-D2was involved inB. dorsalisovarian development. This study showed that some specificCPAP3genes had crucial roles inB. dorsalisdevelopment, and these CP genes could be used as potential targets to control this pest via RNAi.

摘要: Chitinase degrades chitin in the old epidermis or peritrophic matrix of insects, which ensures normal development and metamorphosis. In our previous work, we comprehensively studied the function ofSfCht7inSogatella furcifera. However, the number and function of chitinase genes inS.furciferaremain unknown. Here, we identified 12 full-length chitinase transcripts fromS.furcifera, which included nine chitinase (Cht), two imaginal disc growth factor (IDGF), and one endo-beta-N-acetylglucosaminidase (ENGase) genes. Expression analysis results revealed that the expression levels of eight genes (SfCht3,SfCht5,SfCht6-1,SfCht6-2,SfCht7,SfCht8,SfCht10, andSfIDGF2) with similar transcript levels peaked prior to molting of each nymph and were highly expressed in the integument. Based on RNA interference (RNAi), description of the functions of each chitinase gene indicated that the silencing ofSfCht5,SfCht10, andSfIDGF2led to molting defects and lethality. RNAi inhibited the expressions ofSfCht5,SfCht7,SfCht10, andSfIDGF2, which led to downregulated expressions of chitin synthase 1 (SfCHS1,SfCHS1a, andSfCHS1b) and four chitin deacetylase genes (SfCDA1,SfCDA2,SfCDA3, andSfCDA4), and caused a change in the expression level of two trehalase genes (TRE1andTRE2). Furthermore, silencing ofSfCht7induced a significant decrease in the expression levels of three wing development-related genes (SfWG,SfDpp, andSfHh). In conclusion,SfCht5,SfCht7,SfCht10, andSfIDGF2play vital roles in nymph-adult transition and are involved in the regulation of chitin metabolism, andSfCht7is also involved in wing development; therefore, these genes are potential targets for control ofS.furcifera.

摘要: Sensory neuron membrane proteins(SNMPs) play a critical role in insect chemosensory system. Previously, three SNMPs were identified, characterized and functionally investigated in a lepidopteran model insect,Bombyx mori. However, whether these results are consistent across other lepidopteran species are unknown. Here genome and transcriptome data analysis, expression profiling, quantitative real-time PCR (qRT-PCR) and the yeast hybridization system were utilized to examinesnmpgenes ofHelicoverpa armigera, one of the most destructive lepidopteran pests in cropping areas.In silicoexpression and qRT-PCR analyses showed that, just as theB. mori snmpgenes,H. armigera snmp1(Harmsnmp1) is specifically expressed in adult antennae.Harmsnmp2is broadly expressed in multiple tissues including adult antennae, tarsi, larval antennae and mouthparts.Harmsnmp3is specifically expressed in larval midguts. Further RNAseq analysis suggested that the expression levels ofHarmsnmp2andHarmsnmp3differed significantly depending on the plant species on which the larvae fed, indicating they may be involved in plant-feeding behaviours. Yeast hybridization results revealed a protein-protein interaction between HarmSNMP1 and the sex pheromone receptor, HarmOR13. This study demonstrated that SNMPs may share same functions and mechanisms in different lepidopteran species, which improved our understanding of insectsnmpgenes and their functions in lepidopterans.

摘要: The fall armyworm (FAW),Spodoptera frugiperda, is a major pest native to the Americas that has recently invaded the Old World. Point mutations in the target-site proteins acetylcholinesterase-1 (ace-1), voltage-gated sodium channel (VGSC) and ryanodine receptor (RyR) have been identified inS. frugiperdaas major resistance mechanisms to organophosphate, pyrethroid and diamide insecticides respectively. Mutations in the adenosine triphosphate-binding cassette transporter C2 gene (ABCC2) have also been identified to confer resistance to Cry1F protein. In this study, we applied a whole-genome sequencing (WGS) approach to identify point mutations in the target-site genes in 150 FAW individuals collected from China, Malawi, Uganda and Brazil. This approach revealed three amino acid substitutions (A201S, G227A and F290V) ofS. frugiperda ace-1, which are known to be associated with organophosphate resistance. The Brazilian population had all threeace-1point mutations and the 227A allele (mean frequency = 0.54) was the most common. Populations from China, Malawi and Uganda harbored two of the threeace-1point mutations (A201S and F290V) with the 290V allele (0.47-0.58) as the dominant allele. Point mutations in VGSC (T929I, L932F and L1014F) and RyR (I4790M and G4946E) were not detected in any of the 150 individuals. A novel 12-bp insertion mutation in exon 15 of theABCC2gene was identified in some of the Brazilian individuals but absent in the invasive populations. Our results not only demonstrate robustness of the WGS-based genomic approach for detection of resistance mutations, but also provide insights for improvement of resistance management tactics inS. frugiperda.