RNA-seq of three Spodoptera frugiperda tissues (Midgut, Fat body, Hemocytes), at 2 time-points (8h and 15h) after infestation by entomopathogenic nematodes Steinernema carpocapsae/Xenorhabdus nematophila
ABSTRACT: Nematodes such as Steinernema carpocapsae are used as organic pesticides because of their ability to prey on live insects. They do so thanks to their symbiotic bacteria, that they release within the hemocoel of insects. In this study we wanted to study how Spodoptera frugiperda, a Lepidoptera pest of crops becoming invasive around the world, defend themselves against the nematodes. We infested S. frugiperda larvae with nematodes and dissected three tissues: the midgut, the fat body and the hemocytes at two time-points: 8 h and 15 h after infestation. We performed single-end RNA-seq on these samples to study the tissue specificity of S. fru response, as well as its dynamic.
Project description:We report small RNA sequencing of the entomopathogenic nematode Steinernema carpocapsae. The nematodes were grown in liquid culture in homogenates of pig kidney/fat and infective juveniles were gathered. Then Galleria mellonella insect haemolymph was added to simulate insect infection, control nematodes weren't added haemolymph. Nematodes were collected after two hours after haemolymph addition. infective juveniles S. carpocapsae were incubated with and without haemolymph, three replicates
Project description:This research investigates the molecular mechanisms of trait deterioration of two experimental lines of entamopathogenic nematodes, an inbred line (L5M) and its original parental line (OHB), created by sub-culturing different experimental lines of the nematode-bacterium complex over 20 passages in insect hosts. These lines differed in their virulence, heat tolerance and fecundity . Transcriptional profiles of the two experimental lines were determined and select differentially expressed genes were validated by quantitative PCR. Samples from four biological replicates each of the parental strain (OHB) and the laboratory strain (L5M) were hybridized to the custom H. bacteriophora arrays.
Project description:Spodoptera frugiperda invaded China in the end of 2018 and has caused severe damage to maize and other crops. Several S. frugiperda naturally parasitized by nematodes were observed in Hainan Province, China. The morphological characteristics based on the results of scanning electron microscopy indicated that the nematode belongs to the family Mermithidae. Additionally, coding sequences for the 18?S and 28?S rDNA were amplified from the nematode genome, and phylogenetic analysis revealed that the nematode belongs to Ovomermis sinensis, a known entomoparasitic nematode. Our finding is the first record that S. frugiperda was naturally parasitized by O. sinensis. The results of this study are of great significance for potential biological control of S. frugiperda by indigenous natural beneficial organisms, i.e. O. sinensis within an integrated pest management system.Spodoptera frugiperda invaded China in the end of 2018 and has caused severe damage to maize and other crops. Several S. frugiperda naturally parasitized by nematodes were observed in Hainan Province, China. The morphological characteristics based on the results of scanning electron microscopy indicated that the nematode belongs to the family Mermithidae. Additionally, coding sequences for the 18?S and 28?S rDNA were amplified from the nematode genome, and phylogenetic analysis revealed that the nematode belongs to Ovomermis sinensis, a known entomoparasitic nematode. Our finding is the first record that S. frugiperda was naturally parasitized by O. sinensis. The results of this study are of great significance for potential biological control of S. frugiperda by indigenous natural beneficial organisms, i.e. O. sinensis within an integrated pest management system.
Project description:We wished to investigate if adaptation to host-plant diet is the basis of differentiation for two strains of Spodoptera frugiperda (Lepidoptera:Noctuidae). We performed reciprocal transplant experiments in laboratory conditions, feeding each strain (sf-C and sf-R) with artificial diet, corn plants or rice plants. RNA-Seq was performed on pooled 4th instar larvae from this experiment. We compared this transcriptional response with that of individual 4th instar larvae collected in corn and grass fields in Florida.
Project description:Entomopathogenic nematodes (EPNs) of the genera Heterorhabditis are obligate and lethal insect parasites. In recent years they have been used increasingly as biological control agents. These EPNs are symbiotically associated with bacteria of the genera Photorhabdus. The bacterial symbionts are essential to kill the host (within 24-48 hours) and digest its tissues to provide nutrients for themselves as well for expanding nematodes. Drosophila larvae are suitable insect hosts and part of the tripartite model system we used before to show the importance of haemolymph clotting and eicosanoids during the infection. We used the well-established tripartite model (Drosophila, nematodes, bacteria), DNA chips and bioinformatic tools to compare gene expression in non-infected and infected fly larvae. We focused on the early time point of nematode infection and therefore infected Drosophila larvae using H. bacteriophora harbouring GFP-labelled P. luminescens bacteria. Infected (GFP positive) larvae were collected 6 hours after infection.
Project description:Dysregulation of adenosine (Ado) homeostasis has been observed in both rodent models and human patients of Huntington’s disease (HD). However, the underlying mechanisms of Ado signaling in HD pathogenesis is still unclear. In this study we examined influence of Ado signaling on Drosophila HD model. We further examined the transcription profile of AdoR mutants by microarray analysis to identified a downstream target of AdoR signaling, which mediates the AdoR effects on HD pathology. Our findings have important implications for the crosstalk between Ado signaling and pathogenic effects of HD as well as other human diseases associated with polyglutamine aggregation.
Project description:We report the application of next generation RNA sequencing to analyze the transcriptional response of Drosophila adult flies to infection by the insect pathogenic nematodes Heterorhabditis bacteriophora and their mutualistic bacteria Photorhabdus luminescens, either separately or together. We find that Heterorhabditis and Photorhabdus differentially modulate a large number of genes, many of which participate in metabolic functions, stress responses, repression of gene transcription and neuronal activities. We have also identified Drosophila genes with potential role in nematode recognition and others with putative anti-nematode properties. These findings generate novel insights into how the host immune function is shaped to respond against nematode parasites and their associated bacteria. Transcriptional profiles of Drosophila wild-type adult flies infected with Heterorhabditis bacteriophora carrying or lacking Photorhabdus or the bacteria alone were generated at 12 and 30 hours post infection using Illumina deep sequencing technology.
Project description:Mycetoma is a neglected chronic and granulomatous infection primarily associated with the fungal pathogen Madurella mycetomatis. Infection is characterised by the formation of fungal grains inside the infected tissue which commonly result in severe deformity and disability. Currently the biochemical processes and interactions between host and pathogen which result in grain formation are unknown. Furthermore, the infection process in mammals takes months to fully develop. In order to unravel these processes Galleria mellonella larvae were infected with M. mycetomatis and hyphae and grain formation, survival, fungal burden and proteomic responses of larvae were monitored for 10 days. At 24 h post infection proteins indicative of muscle invasion and humoral immune response activation were enriched in infected larval hemolymph. By 72 h immune related hdd11 was increased 337 fold, heat shock proteins 90 was increased 40 fold and glutathione-S-transferase was increased 25 fold. By 7 days post infection proteins which were associated with grain formation (hdd11 [533 fold], hemocentin [54 fold]) and a range of antimicrobial peptides were enriched. During the 7 day period a variety of proteins were decreased in infected hemolymph (e.g. hexamerin, apolipophorin and cationic peptide CP8). This data also identified 75 M. mycetomatis proteins released into hemolymph during infection. Proteins were also extracted from M. mycetomatis grains taken from larvae infected for 24, 72 and 7 days. These proteins give an insight into the interactions between the larval immune response and M. mycetomatis at the cellular levels during infection. These results identify similarities between the infection processes of M. mycetomatis in G. mellonella larvae and in humans and identify novel proteins from M. mycetomatis which may play a crucial role in grain development.
Project description:This study assessed the development of disseminated candidiasis within Galleria mellonella larvae and characterised the proteomic responses of Candida albicans to larval hemolymph. Infection of larvae with an inoculum of 1 × 106 yeast cell reduced larval viability 24 (53.33 ± 3.33%), 48 (33.33 ± 3.33%) and 72 (6.66 ± 3.33%) hour post infection. C. albicans infection quickly disseminated from the site of inoculation and the presence of yeast and hyphal forms were found in nodules extracted from infected larvae at 6 and 24 hours. A range of proteins secreted during infection of G. mellonella were detected in larval hemolymph and these were enriched for biological processes such as interaction with host and pathogenesis. The candicidal activity of hemolymph after immediate incubation of yeast cells resulted in a decrease in yeast cell viability (0.23 ± 0.03 × 106, p < 0.05) as compared to control (0.99 ± 0.01 × 106). extracellular (in vivo) proteome of C. albicans in larval hemolymph were assessed. C. albicans responds to incubation in hemolymph ex vivo by the induction of an oxidative stress response, a decrease in proteins associated with protein synthesis and an increase in glycolytic proteins.
Project description:Two Steinernema isolates found in Louisiana and Mississippi were later identified as isolates of S. rarum. DNA sequences of ITS regions of the United States isolates are identical with sequences of Argentinean S. rarum strains Samiento and Noetinger and differ by two bases from the Arroyo Cabral isolate from Córdoba, Argentina. SEM observations revealed several new structures in the isolates from the US: female face views have a hexagonal-star perioral disc and eye-shaped lips; some females do not have cephalic papillae; lateral fields of infective juveniles are variable; there are two openings observed close to the posterior edge of the cloaca. Virulence of the US isolates to Anthonomus grandis, Diaprepes abbreviatus, Solenopsis invicta, Coptotermes formosanus, Agrotis ipsilon, Spodoptera frugiperda, and Trichoplusia ni and reproductive potential were evaluated in comparison with other heterorhabditid and steinernematid nematodes. Results such as particularly high virulence to S. frugiperda indicate that the biocontrol potential of the new S. rarum strains merits further study.