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: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: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: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
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:An analysis of the impact of infection by Buchnera aphidicola APS (isolated from Acyrthosiphon pisum strain LL01) on gene expression of S2 cells. All comparisons are made against a pool of RNA from S2 cells not exposed to B. aphidicola. B. aphidicola freshly isolated from the aphids, and data are collected at 1, 6 and 24 hours after exposure of S2 cells to the B. aphidicola preparation. Keywords: time course, Buchnera aphidicola APS, aphids, Drosophila melanogaster S2 cells
Project description:Aphid adaptation to harsh winter conditions is illustrated by an alternation of their reproductive mode. Aphids detect photoperiod shortening by sensing the length of the night and switch from viviparous parthenogenesis in spring and summer, to oviparous sexual reproduction in autumn. The photoperiodic signal is transduced from the head to the reproductive tract to change the fate of the future oocytes from mitotic diploid embryogenesis to haploid formation of gametes. Because of viviparous parthenogenesis, the whole process takes place in three consecutive generations. To understand the molecular basis of the switch in the reproductive mode, a transcriptomic approach was used to detect significantly regulated transcripts in the heads of the pea aphid Acyrthosiphon pisum. The transcriptomic profiles of the heads of the first generation were slightly affected by photoperiod shortening. This suggests that trans-generation signaling does not occur between the grand-mothers and the viviparous embryos they contain. By analogy, many of the genes regulated in the heads of the second generation are implicated in visual functions, photoreception and cuticle structure. The modification of the cuticle could decrease the storage of N-β-alanyldopamine and provoke an increase in free dopamine concentration. Based in results in Drosophila, modification of the insulin pathway could cause a decrease of juvenile hormones in short-day reared aphids.
Project description:An analysis of the impact of infection by Buchnera aphidicola APS (isolated from Acyrthosiphon pisum strain LL01) on gene expression of S2 cells. All comparisons are made against a pool of RNA from S2 cells not exposed to B. aphidicola. B. aphidicola freshly isolated from the aphids, and data are collected at 1, 6 and 24 hours after exposure of S2 cells to the B. aphidicola preparation. Keywords: time course, Buchnera aphidicola APS, aphids, Drosophila melanogaster S2 cells All comparisons are made against a pool of RNA from S2 cells not exposed to B. aphidicola. B. aphidicola freshly isolated from the aphids, and data are collected at 1, 6 and 24 hours after exposure of S2 cells to the B. aphidicola preparation.
Project description:Tyrosine (Tyr, Y) and phenylalanine (Phe, F) synthesis is shared by the pea aphid and its symbiont Buchnera aphidicola.These aromatic amino acids are essential for the pea aphid growth and development. To characterize the molecular mechanisms, at gene transcriptional level, underlying this symbiotic integrated network pea aphids (Acyrthosyphon pisum, clone LL01) were reared on (i) standard artificial diet (AP3) and (ii) on the same AP3 medium depleted of Tyr (Y) and Phe (F). From each of the two groups, aphids were collected at specific time points and dissected: 12 h (D0), 1 day (D1), 2 days (D2), 3 days (D3), 4 days (D4), 5 days (D5) and 7 days (D7). Total RNA, to be used in gene expression analysis by arrays, was extracted, under the two rearing conditions, from two tissues: gut [from 20 aphids per sample at all 7 time points] and bacteriocytes [from 25 aphids per sample at 4 time points: 3 days (D3), 4 days (D4), 5 days (D5) and 7 days (D7)]. At each time point we included three biological replicates.