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: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.
2015-03-05 | GSE55700 | GEO
Project description:partial genomic scaffold of fig wasps
Project description:Plant response to insect feeding appears to be highly specific with regard to the organisms in the system. Here, we report on the interaction between grapevine Vitis vinifera plants and a phloem-feeding insect pest, the vine mealybug Planococcus ficus. Plants were exposed to P. ficus for periods of 6 hours and 96 hours, after which they were analysed for gene expression levels using microarrays and quantitative real-time PCR (qPCR). Both methods showed that grapevine displayed only a minimal response to mealybug feeding at the transcript level at both time periods. Intermediate grapevine exposure times (24, 48 and 72 hours) to P. ficus feeding were investigated using qPCR analysis of ten additional genes associated with known plant defense responses. Results showed that only a single gene, pathogenesis-related protein 1, was differentially expressed after 48 hours of mealybug feeding. During the course of mealybug feeding, however, a number of other genes were significantly up- or down-regulated at certain time points. Thus, it appears as if grapevine responds minimally to feeding by P. ficus as well as within a very narrow time period. The relative lack of grapevine plant defense mechanisms may be a result of the feeding strategies of mealybugs.
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.