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In insects, proteolytic cascades medicated by serine proteases (SPs), serine protease homologs (SPHs) and prophenoloxidases (PPOs) control several physiological processes, notably the innate immunity. However, no attempts have been made to identify and characterize these genes in Spodoptera frugiperda, one of the most destructive agricultural pests. In this study, 83 SPs, 26 SPHs and four PPOs were respectively identified in S. frugiperda genome based on homology blast against those of other insects. We then analyzed the domain organization of these proteins and assigned them into different groups by phylogenetic reconstruction. Furthermore, the mRNA levels of clip-domain SPs/SPHs (cSPs/cSPHs) and PPOs were quantified in response to a mixed infection of Micrococcus luteus and Escherichia coli, and obvious accumulations were recorded in immune tissues, including hemocytes and fat body. In the latter study, we profiled the expression patterns of highly expressed cSPs and PPOs in different developmental stages, including egg, larva, pupa, female and male adults. It was shown that most cSPs were abundantly expressed in adults, while PPOs were detected at high levels in both egg and larval stages. These current findings substantially add to our understanding of the roles of S. frugiperda SPs, SPHs and PPOs in immune regulation and further lay a solid foundation for uncovering the interaction mechanisms between insects and pathogens.

As a major invasive pest in China

Background Spodoptera frugiperda (J. E. Smith), commonly known as fall armyworm (FAW), is one of the most destructive agricultural pests in the world and has posed a great threat to crops. The improper use of insecticides has led to rapid development of resistance. However, the genetic data available for uncovering the insecticide resistance mechanisms are scarce. Methods In this study, we used PacBio single-molecule real-time (SMRT) sequencing aimed at revealing the full-length transcriptome profiling of the FAW larval brain to obtain detoxification genes. Results A total of 18,642 high-quality transcripts were obtained with an average length of 2,371 bp, and 11,230 of which were successfully annotated in six public databases. Among these, 5,692 alternative splicing events were identified.

As a major invasive pest in China, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) has caused great damage to crops. Hymenopteran parasitoids, especially the braconid wasps, play crucial roles in depressing pest populations. However, there was little information about the ideal storage of parasitoids to achieve their mass-rearing. Here, we identified a dominant parasitoid of S. frugiperda, Microplitis manilae (Ashmead) (Hymenoptera: Braconidae), in the Hainan province of China with a field parasitism rate of 5.66–19.10%. The investigation of biological parameters revealed that the parasitism rate of M. manilae significantly decreased with an increase in both wasp adult longevity and host age, and the wasp of 1–3 d post eclosion performed best on the first instar of host larvae, showing the highest parasitism rate. We also discovered that the decreased temperature from 30 to 20 °C greatly extended the longevity of wasp adults, and a similar result was observed after feeding on 10% sucrose water compared with sterile water. Then, the effects of different pupal cold storage temperatures (4 and 10 °C), storage period (prepupa, middle-aged pupa, late-aged pupa) and storage time (5, 10 or 20 d) on the emergence rate, parasitism rate, female proportion and longevity of M. manilae were investigated. The results demonstrated that the middle-aged wasp pupae stored at 10 °C for 5–10 d possessed a stronger parasitic ability and longer longevity. These findings may promote the flexibility and efficacy of large-scale production of M. manilae, thus contributing to its biological field control against S. frugiperda.

Background Spodoptera frugiperda (J. E. Smith), commonly known as fall armyworm (FAW), is one of the most destructive agricultural pests in the world and has posed a great threat to crops. The improper use of insecticides has led to rapid development of resistance. However, the genetic data available for uncovering the insecticide resistance mechanisms are scarce. Methods In this study, we used PacBio single-molecule real-time (SMRT) sequencing aimed at revealing the full-length transcriptome profiling of the FAW larval brain to obtain detoxification genes. Results A total of 18,642 high-quality transcripts were obtained with an average length of 2,371 bp, and 11,230 of which were successfully annotated in six public databases. Among these, 5,692 alternative splicing events were identified.