Project description:A striking property of the ancient and obligate mutualism between figs and their pollinating wasps is that fig wasps consistently oviposit in the inner flowers of the fig syconium (gall flowers, which develop into galls that house developing larvae), but typically do not use the outer ring of flowers (seed flowers, which develop into seeds). To better understand differences between gall and seed flowers that might influence oviposition choices, and the unknown mechanisms underlying gall formation, we used a metatranscriptomic approach to analyze eukaryotic gene expression within fig flowers at the time of oviposition choice and early gall development. Consistent with the unbeatable seed hypothesis, which posits that only a portion of fig flowers are physiologically capable of responding to gall induction or supporting larval development, we found significant differences in gene expression assigned to defense and metabolism between gall- and seed flowers in receptive syconia. Transcripts assigned to flavonoids and defense were especially prevalent in receptive gall flowers, and carbohydrate metabolism was significantly up-regulated relative to seed flowers. In turn, high expression of the venom gene icarapin during wasp embryogenesis within galled flowers distinguishes it as a candidate gene for gall initiation. In response to galling, the fig significantly up-regulates the expression of chalcone synthase, which previously has been connected to gall formation in other plants. This study simultaneously evaluates the gene expression profile of both mutualistic partners in a plant-insect mutualism and provides evidence for a stability mechanism in the ancient fig-fig wasp association.
Project description:A striking property of the ancient and obligate mutualism between figs and their pollinating wasps is that fig wasps consistently oviposit in the inner flowers of the fig syconium (gall flowers, which develop into galls that house developing larvae), but typically do not use the outer ring of flowers (seed flowers, which develop into seeds). To better understand differences between gall and seed flowers that might influence oviposition choices, and the unknown mechanisms underlying gall formation, we used a metatranscriptomic approach to analyze eukaryotic gene expression within fig flowers at the time of oviposition choice and early gall development. Consistent with the unbeatable seed hypothesis, which posits that only a portion of fig flowers are physiologically capable of responding to gall induction or supporting larval development, we found significant differences in gene expression assigned to defense and metabolism between gall- and seed flowers in receptive syconia. Transcripts assigned to flavonoids and defense were especially prevalent in receptive gall flowers, and carbohydrate metabolism was significantly up-regulated relative to seed flowers. In turn, high expression of the venom gene icarapin during wasp embryogenesis within galled flowers distinguishes it as a candidate gene for gall initiation. In response to galling, the fig significantly up-regulates the expression of chalcone synthase, which previously has been connected to gall formation in other plants. This study simultaneously evaluates the gene expression profile of both mutualistic partners in a plant-insect mutualism and provides evidence for a stability mechanism in the ancient fig-fig wasp association. We examined two different Ficus flower types at two different time points. Each sample contained a pool of hundreds of individual flowers from multiple sycomia.
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:Upon pathogenic infection, drosophila larval host mounts an immune response. Parasitic wasps inject venom that contain virulence factors during oviposition, which can elicit host immune response, and in some cases, suppress host immune responses altogether. Several microarray experiments have been performed on different classes of parasitic wasps. We wanted to compare how Ganaspis xanthopoda-infected hosts respond compared to other classes of parasitic wasps.
Project description:Highly specific amplification of complex DNA pools without bias or template-independent products (TIPs) remains a challenge. We have developed a procedure using phi29 DNA polymerase and trehalose and optimized control of amplification to create micrograms of specific amplicons without TIPs from down to sub-femtograms of DNA. The amplicons from 5 ng and 0.5 ng DNA, which were from originally good quality of gDNA (05-050), or partially degraded gDNA (04-018), faithfully demonstrated all previously known heterozygous segmental duplications and deletions (3 Mb to 18 kb) located on chromosome 22 and even a homozygous deletion smaller than 1 kb with high resolution chromosome-wide CGH. Specifically, HR-CGH with 5 ng-input gDNA-derived amplicon detected all previously known chromosomal segmental aberrations in chromosome 22 in samples from two different probands, and was indistinguishable from the HR-CGH result with native gDNA from the same probands (Fig. 4, Fig. S3 and S4). The break points were also precisely demonstrated. These include a heterozygous genomic segmental duplication (3 copies, 3 Mb in size, sample 05-050, Fig. 4) and 2 different heterozygous deletions (1 copy, 1.4 Mb and 18 kb respectively, sample 04-018, Fig. S4), all of which are located in or bounded by regions of low copy repeats (LCRs). In addition, a previous known homozygous deletion of 975 bp (in 04-018 and 05-050) was again accurately demonstrated (05-050 data showed in Fig. 4c), although sometimes (04-018) the data was a little noisier than with unamplified DNA (Fig. S4d). In contrast, the Wpa-40oC resulted in abundant signal noise and failed in detection of these copy number aberrations (Fig. 4, Fig. S3, S4). Impressively, HR-CGH with 0.5 ng gDNA-derived amplicons via Wpa also clearly detected the known CNVs, although noisier (Fig. S4). The 0.1ng gDNA derived amplicons via Wpa could not unambiguously show CNVs because of higher variability of signals, but the CNVs’ patterns were mostly well maintained (Fig. S4 for 04-018). We did also notice some locus-imbalance in the amplicon, however this was minimized, and was reproducible when the input was above a certain threshold amount, and it could be well compensated if the same amplified reference sample was applied in parallel as showed above. Keywords: Whole-pool amplification, high resolution comparative genome hybridization (HR-CGH)
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:Upon pathogenic infection, drosophila larval host mounts an immune response. Parasitic wasps inject venom that contain virulence factors during oviposition, which can elicit host immune response, and in some cases, suppress host immune responses altogether. Several microarray experiments have been performed on different classes of parasitic wasps. We wanted to compare how Ganaspis xanthopoda-infected hosts respond compared to other classes of parasitic wasps. Third instar y w larvae from a 2-day egglay were infected with G. xanthopoda for three and six hours, respectively, by introducing waps in petri-dish containing larvae. Controls were handled side-by-side without introducing wasps. Host larvae were immediately dissected, infection confirmed by presence of wasp egg, and frozen in liquid nitrogen and ground in Trizol. RNA was isolated and checked by agarose gel-electrophoresis. Samples were then sent to the Microarray Core Facility at Weill Cornell Medical College.