Project description:Background The generalist dipteran pupal parasitoid Nasonia vitripennis injects 79 venom peptides into the host before egg laying. This venom induces several important changes in the host, including developmental arrest, immunosuppression, and alterations to normal metabolism. It is hoped that diverse and potent bioactivities of N. vitripennis venom provide an opportunity for the design of novel acting drugs. However, currently very little is known about the individual functions of N. vitripennis venom peptides and less than half can be bioinformatically annotated. The paucity of annotation information complicates the design of studies that seek to better understand the potential mechanisms underlying the envenomation response. Although the RNA interference system of N. vitripennis provides an opportunity to functionally characterise venom encoding genes, with 79 candidates this represents a daunting task. For this reason we were interested in determining the expression levels of venom encoding genes in the venom gland, such that this information could be used to rank candidate venoms. To do this we carried out deep sequencing of the transcriptome of the venom gland and neighbouring ovary tissue and used RNA-seq to measure expression from the 79 venom encoding genes. The generation of a specific venom gland transcriptome dataset also provides further opportunities to investigate novel features of this highly specialised organ. Results High throughput sequencing and RNA-seq revealed that the highest expressed venom encoding gene in the venom gland was a serine protease called Nasvi2EG007167, which has previously been implicated in the apoptotic activity of N. vitripennis venom. As expected the RNA-seq confirmed that the N. vitripennis venom encoding genes are almost exclusively expressed in the venom gland relative to the neighbouring ovary tissue. Novel peptides appear to perform key roles in N. vitripennis venom function as only four of the highest 15 expressed venom encoding genes are bioinformatically annotationed. The high throughput sequencing data also provided evidence for the existence of an additional 471 novel genes in the Nasonia genome that are expressed in the venom gland and ovary. Finally, metagenomic analysis of venom gland transcripts identified viral transcripts that may play an important part in the N. vitripennis venom function. Conclusions The expression level information provided here for the 79 venom encoding genes provides an unbiased dataset that can be used by the N. vitripennis community to identify high value candidates for further functional characterisation. These candidates represent bioactive peptides that have value in drug development pipelines.
Project description:Diachasmimorpha longicaudata parasitoid wasps carry a symbiotic poxvirus, known as DlEPV, within the female wasp venom gland. We sequenced RNA from venom gland tissue to identify DlEPV orthologs for 3 conserved poxvirus core genes. The DlEPV ORFs identified from this transcriptome were used to design primers for downstream RT-qPCR analysis and RNAi knockdown experiments.
Project description:Parasitoid wasps of the species Diachasmimorpha longicaudata are associated with a heritable poxvirus, known as DlEPV, that is stored in the venom gland of adult female wasps and transferred to tephritid fly hosts of the wasps during oviposition. We conducted a RNA-seq differential expression analysis to gain insight on how DlEPV can replicate in both wasps and their fly hosts but only cause pathogenic effects during replication in flies. Our analysis revealed that 91.2% (176 of 193) of DlEPV genes showed significant differential expression during peak virus replication in wasp venom glands compared to parasitized flies. Over 80% of DlEPV replication genes were significantly upregulated in wasps, while 79% of DlEPV putative virulence genes were significantly upregulated in fly hosts. These data therefore support a dichotomy of viral function, where virus replication is promoted in wasp tissue and virulence in host tissue. Such a division of viral activity could represent an important adaptation to maintain a stable symbiosis between this virus and its associated parasitoid.
Project description:Seasonal photoperiodic changes have strong impact on development in Nasonia vitripennis. Here, Using high-throughput Reduced Representation Bisulfite Sequencing (RRBS) and single-molecule-based sequencing, we generated DNA methylation maps of female wasps maintained in long vs short day. We have identified differential methylated loci that encode the photoperiodic change. analysis of DNA methylation in female wasps maintained in long vs short day, using RRBS followed by Illumina sequencing
Project description:We quantified genome-wide total and allele-specific expression in two non-social parasitoids wasp species Nasonia vitripennis and Nasonia giraulti and their reciprocal F1 hybrids. No parent-of-origin effect in allelic expression was found for >8,000 informative genes, suggesting lack of genomic imprinting in adult Nasonia. Gene expression divergence between Nv and Ng could be attributed to both significant cis- and trans- regulatory changes during evolution.
Project description:The extraordinary range in the degree of sexual dimorphism (SD) among animal species is widely perceived to be caused in part by differences in patterns of sexual selection, but sex-specific adaptations and sex chromosome differences also play a role. Studies in insects have discovered a substantial number of sex-biased genes, but little is known about the epigenetic basis of SD. The degree and genome-wide distribution of sex-biased expression become interesting questions in hymenoptera species with haplodiploid sex-determination. To study the genetic and epigenetic architecture of SD and understand the conservation and evolution of sex-biased expression in a haplodiploid system that lacks sex chromosomes, we performed RNA-seq and whole-genome bisulfite sequencing in female and male adult samples of two parasitoid wasp species, Nasonia vitripennis and Nasonia giraulti. More than 75% of the expressed genes displayed significantly sex-biased expression. Both the number and the degree of sex-biased genes are higher than insects like Drosophila melanogaster, which have sex-chromosome mediated sex determination. Females from the two Nasonia species have far more similar expression profiles than does the contrast between the two sexes within either species. Interestingly, the extremely male- and female-biased genes are enriched for totally different functional categories: male-biased genes are highly enriched for key enzymes in sex-pheromone synthesis; female-biased genes are enriched for nuclear-located genes that are responsible for epigenetic regulation of gene expression. Unlike gene expression profiles, DNA methylomes are more similar within species, and no stable differentially methylated genes have been found between the two sexes, suggesting that DNA methylation is not directly responsible for the molecular basis of SD. However, methylation status does influence sex-biased expression: 80% of female-biased genes are methylated, which is more than two-fold higher than the genome average (30%); almost all male-biased and sex-specific genes are non-methylated, which is consistent with the fact that methylated genes have house-keeping functions and a broader expression breadth. Evolutionarily, male-biased genes have greater sequence divergence between the two species, and they are more likely to have a functional paralog in the Nasonia genome. Sex-specific genes have significantly higher non-synonymous substitution rates and dN/dS ratios. In addition, local clusters of sex-biased genes in the genome may have epigenetic properties similar to the sex chromosome. In summary, Nasonia accomplish a striking degree of sex-differential expression through a difference in ploidy along with associated differences in methylations status. Whole-genome bisulfite sequencing of 24-hour adult whole body samples of Nasonia vitripennis and Nasonia giraulti using Iilumina sequencing.
Project description:The extraordinary range in the degree of sexual dimorphism (SD) among animal species is widely perceived to be caused in part by differences in patterns of sexual selection, but sex-specific adaptations and sex chromosome differences also play a role. Studies in insects have discovered a substantial number of sex-biased genes, but little is known about the epigenetic basis of SD. The degree and genome-wide distribution of sex-biased expression become interesting questions in hymenoptera species with haplodiploid sex-determination. To study the genetic and epigenetic architecture of SD and understand the conservation and evolution of sex-biased expression in a haplodiploid system that lacks sex chromosomes, we performed RNA-seq and whole-genome bisulfite sequencing in female and male adult samples of two parasitoid wasp species, Nasonia vitripennis and Nasonia giraulti. More than 75% of the expressed genes displayed significantly sex-biased expression. Both the number and the degree of sex-biased genes are higher than insects like Drosophila melanogaster, which have sex-chromosome mediated sex determination. Females from the two Nasonia species have far more similar expression profiles than does the contrast between the two sexes within either species. Interestingly, the extremely male- and female-biased genes are enriched for totally different functional categories: male-biased genes are highly enriched for key enzymes in sex-pheromone synthesis; female-biased genes are enriched for nuclear-located genes that are responsible for epigenetic regulation of gene expression. Unlike gene expression profiles, DNA methylomes are more similar within species, and no stable differentially methylated genes have been found between the two sexes, suggesting that DNA methylation is not directly responsible for the molecular basis of SD. However, methylation status does influence sex-biased expression: 80% of female-biased genes are methylated, which is more than two-fold higher than the genome average (30%); almost all male-biased and sex-specific genes are non-methylated, which is consistent with the fact that methylated genes have house-keeping functions and a broader expression breadth. Evolutionarily, male-biased genes have greater sequence divergence between the two species, and they are more likely to have a functional paralog in the Nasonia genome. Sex-specific genes have significantly higher non-synonymous substitution rates and dN/dS ratios. In addition, local clusters of sex-biased genes in the genome may have epigenetic properties similar to the sex chromosome. In summary, Nasonia accomplish a striking degree of sex-differential expression through a difference in ploidy along with associated differences in methylations status. Profiling of expression levels in Nasonia vitripennis and Nasonia giraulti adult male and female samples using Illumina RNA-seq
Project description:Seasonal photoperiodic changes have strong impact on development in Nasonia vitripennis. Here, Using high-throughput Reduced Representation Bisulfite Sequencing (RRBS) and single-molecule-based sequencing, we generated DNA methylation maps of female wasps maintained in long vs short day. We have identified differential methylated loci that encode the photoperiodic change.