Project description:Bioinformatic prediction, deep sequencing of microRNA and expression analysis during phenotypic plasticity in the pea aphid acyrthosiphon pisum We developed high throughput Solexa sequencing and bioinformatic analyses of the genome of the pea aphid Acyrthosiphon pisum in order to identify the first miRNAs from a hemipteran insect. By combining these methods we identified 155 miRNAs including 56 conserved and 99 new miRNAs. Moreover, we investigated the regulation of these miRNAs in different alternative morphs of the pea aphid by analysing the expression of miRNAs across the switch of reproduction mode.
Project description:Bioinformatic prediction, deep sequencing of microRNA and expression analysis during phenotypic plasticity in the pea aphid acyrthosiphon pisum We developed high throughput Solexa sequencing and bioinformatic analyses of the genome of the pea aphid Acyrthosiphon pisum in order to identify the first miRNAs from a hemipteran insect. By combining these methods we identified 155 miRNAs including 56 conserved and 99 new miRNAs. Moreover, we investigated the regulation of these miRNAs in different alternative morphs of the pea aphid by analysing the expression of miRNAs across the switch of reproduction mode. deep sequencing of small RNAs from parthenogenetic Acyrthosiphon pisum
Project description:We developed high throughput Solexa sequencing and bioinformatic analyses of the genome of the pea aphid Acyrthosiphon pisum in order to identify the first miRNAs from a hemipteran insect. By combining these methods we identified 155 miRNAs including 56 conserved and 99 new miRNAs. Moreover, we investigated the regulation of these miRNAs in different alternative morphs of the pea aphid by analysing the expression of miRNAs across the switch of reproduction mode.
Project description:We developed high throughput Solexa sequencing and bioinformatic analyses of the genome of the pea aphid Acyrthosiphon pisum in order to identify the first miRNAs from a hemipteran insect. By combining these methods we identified 155 miRNAs including 56 conserved and 99 new miRNAs. Moreover, we investigated the regulation of these miRNAs in different alternative morphs of the pea aphid by analysing the expression of miRNAs across the switch of reproduction mode. An array including the 155 aphid microRNAs was designed in order to follow the expression of aphid microRNAs during the modification of reproduction mode of the pea aphid
Project description:The pea aphid, Acyrthosiphon pisum, can host different facultative symbionts (FS), which may provide various benefits to the host, including adaptation to the host plant and resistance to heat or natural enemies (fungi, bacteria, parasitoid wasps). Here, we searched whether and how the presence of some FS could affect a key component of insect innate immunity, the phenoloxidase, under normal and stressed conditions. For this, we used A. pisum clones of different genetic background (LL01, YR2 and T3-8V1) and harboring or not FS (Regiella insecticola (Ri), Hamiltonella defensa (Hd) or Serratia symbiotica (Ss)). Proteomic analysis of aphid hemolymph and PCR indicated that the two A. pisum phenoloxidases, PO1 and PO2, are expressed and translated into protein. They seem mainly secreted as circulating enzymes in the hemolymph and a proteolytic cleavage was not necessary for their activation. PO genes expression was dependent upon the aphid genotypes as well as the amount of PO proteins and activity in the total hemolymph (T3-8V1-Amp > LL01 = YR2-Amp). The presence in YR2 and T3-8V1 clones of Hd or Ri, but not Ss, caused a sharp decrease in PO activity by interfering with both transcription and translation. Microinjection of different types of stressors (yeast, E. coli, latex beads) in YR2 lines affected the survival rate of aphids and in most cases, it also decreases the PO genes expression after 24h, whereas the amount and activity of the proteins varied differently depending on the FS and the stressor, regardless of the genes expression. These data provide new hypothesis on the mechanism by which some facultative symbionts act on the pea aphid immunity.
Project description:Background: The best studied insect-symbiont system is that of aphids and their primary bacterial endosymbiont Buchnera aphidicola. Buchnera inhabits specialized host cells called bacteriocytes, provides nutrients to the aphid and has co-speciated with its aphid hosts for the past 150 million years. We have used a single microarray to examine gene expression in the pea aphid, Acyrthosiphon pisum, and its resident Buchnera. Very little is known of gene expression in aphids, few studies have examined gene expression in Buchnera, and no study has examined simultaneously the expression profiles of a host and its symbiont. Expression profiling of aphids, in studies such as this, will be critical for assigning newly discovered A. pisum genes to functional roles. In particular, because aphids possess many genes that are absent from Drosophila and other holometabolous insect taxa, aphid genome annotation efforts cannot rely entirely on homology to the best-studied insect systems. Development of this dual-genome array represents a first attempt to characterize gene expression in this emerging model system. Results: We chose to examine heat shock response because it has been well characterized both in Buchnera and in other insect species. Our results from the Buchnera of A. pisum show responses for the same gene set as an earlier study of heat shock response in Buchnera for the host aphid Schizaphis graminum. Additionally, analyses of aphid transcripts showed the expected response for homologs of known heat shock genes as well as responses for several genes with unknown functional roles. Conclusions: We examined gene expression under heat shock of an insect and its bacterial symbiont in a single assay using a dual-genome microarray. Further, our results indicate that microarrays are a useful tool for inferring functional roles of genes in A. pisum and other insects and suggest that the pea aphid genome may contain many gene paralogs that are differentially regulated. Keywords: Stress response