Project description:We investigate the potential metabolic costs for Steinernema nematode in relation to the maintenance and vectoring of their Xenorhabdus endosymbionts. we performed a comparative dual RNA-seq analysis of infective juveniles (IJs) of two symbiotic partners: S. carpocapsae-X. nematophila and S. puntauvense-X. bovienii.
Project description:Xenorhabdus nematophila is a Gram-negative bacterium, mutually associated with the soil nematode Steinernema carpocapsae and this nematobacterial complex is parasitic for a broad spectrum of insects. The transcriptional regulator OxyR is widely conserved in bacteria, but the OxyR regulon can vary significantly between species. OxyR activates the transcription of a set of genes that influence cellular defense against oxidative stress. It is also involved in the virulence of several bacterial pathogens. The aim of this study was to identify the X. nematophila OxyR regulon and investigate its role in the bacterial life cycle. An oxyR-mutant was constructed in X. nematophila and phenotypically characterized in vitro and in vivo after reassociation with its nematode partner. OxyR plays a major role during the X. nematophila resistance to oxidative stress in vitro. Transcriptome analysis allowed the identification of 59 genes differentially regulated in the oxyR mutant compared to the parental strain. In vivo, the oxyR mutant was able to reassociate with the nematode as efficiently as the control strain. These nematobacterial complexes harboring the oxyR mutant symbiont were able to rapidly kill the insect larvae in less than 48h after infestation, suggesting that factors other than OxyR could also allow X. nematophila to cope with oxidative stress encountered during this phase of infection in insect. The significant increased number of offspring of the nematobacterial complex when reassociated with the X. nematophila oxyR mutant compared to the control strain, revealed a potential role of OxyR during this symbiotic stage of the bacterial life-cycle.
Project description:Entomopathogenic nematodes, the beneficial soil-dwelling nematodes identified with noteworthy ecological services of insect pest management naturally, harbor and vector obligate bacterial symbionts which together cause rapid insect mortality. The tritrophism among the bacterium-nematode-insect host is a treasure box of biological, molecular and biochemical information that was examined to a limited extent. In this project, we intend to explore the time-course expression of proteins of test insect, Holotrichia serrata larvae, during the progression of larval mortality due to nematode-bacterium infection, more specifically, Heterorhabditis indica-
Photorhabdus luminescens, Steinernema spp. vs Xenorhabdus spp., respectively. The data submitted relates to the insect protein profiles (LC-MSMS) in healthy, infected and morbid, and dead larvae of Holotrichia serrata.
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.
Project description:Entomopathogenic nematodes, the beneficial soil-dwelling nematodes identified with noteworthy ecological services of insect pest management, naturally, harbor and vector obligate bacterial symbionts which together cause rapid insect mortality. The tritrophism among the bacterium-nematode-insect host is a treasure box of biological, molecular and biochemical information that was examined to a limited extent in other studies. We have, herein, aimed at quantifying the concentration and at generating the total proteomic profiles of one insect host, Spodoptera frungiperda, during the progression of infection with 4 EPN and their associated bacteria, as compared to that of healthy controls. The time-course expression of larval proteins of the test insect, Spodoptera frugiperda, during the progression of larval mortality due to nematode-bacterium infection, more specifically,4 different combinations of Heterorhabditis indica-Photorhabdus luminescens, Steinernema spp. vs Xenorhabdus spp., respectively. The proteomic profiling was facilitated through LC-MS/MS. The data submitted relates to the insect protein profiles (LC-MSMS) in healthy, infected and morbid, and dead larvae of Spodoptera frugiperda.
Project description:Parasitism is a major ecological niche for a variety of nematodes. Multiple nematode lineages have specialized as pathogens, including deadly parasites of insects that are used in biological control. We have sequenced and analyzed the draft genomes and transcriptomes of the entomopathogenic nematode Steinernema carpocapsae and four congeners (S. scapterisci, S. monticolum, S. feltiae, and S. glaseri). We used these genomes to establish phylogenetic relationships, explore gene conservation across species, and identify genes uniquely expanded in insect parasites. Protein domain analysis in Steinernema revealed a striking expansion of numerous putative parasitism genes, including certain protease and protease inhibitor families, as well as fatty acid- and retinol-binding proteins. Stage-specific gene expression of some of these expanded families further supports the notion that they are involved in insect parasitism by Steinernema. We show that sets of novel conserved non-coding regulatory motifs are associated with orthologous genes in Steinernema and Caenorhabditis. We have identified a set of expanded gene families that are likely to be involved in parasitism. We have also identified a set of non-coding motifs associated with groups of orthologous genes in Steinernema and Caenorhabditis involved in neurogenesis and embryonic development that are likely part of conserved protein–DNA relationships shared between these two genera.
Project description:A fliZ mutant in the entomopathogenic bacterium X. nematophila is attenuated in virulence in the insect. The goal of this study is to compare transcriptomes of the fliZ mutant and wild type strain to identify the FliZ regulon.
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
