Intensity of Mutualism Breakdown Is Determined by Temperature Not Amplification of Wolbachia Genes
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Author(s)
Rohrscheib, Chelsie E
Frentiu, Francesca D
Horn, Emilie
Ritchie, Fiona K
van Swinderen, Bruno
Weible, Michael W
O'Neill, Scott L
Brownlie, Jeremy C
Year published
2016
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Show full item recordAbstract
Wolbachia are maternally transmitted intracellular bacterial symbionts that infect approximately
40% of all insect species. Though several strains of Wolbachia naturally infect
Drosophila melanogaster and provide resistance against viral pathogens, or provision
metabolites during periods of nutritional stress, one virulent strain, wMelPop, reduces fly
lifespan by half, possibly as a consequence of over-replication. While the mechanisms that
allow wMelPop to over-replicate are still of debate, a unique tandem repeat locus in the
wMelPop genome that contains eight genes, referred to as the “Octomom” locus has been
identified ...
View more >Wolbachia are maternally transmitted intracellular bacterial symbionts that infect approximately 40% of all insect species. Though several strains of Wolbachia naturally infect Drosophila melanogaster and provide resistance against viral pathogens, or provision metabolites during periods of nutritional stress, one virulent strain, wMelPop, reduces fly lifespan by half, possibly as a consequence of over-replication. While the mechanisms that allow wMelPop to over-replicate are still of debate, a unique tandem repeat locus in the wMelPop genome that contains eight genes, referred to as the “Octomom” locus has been identified and is thought to play an important regulatory role. Estimates of Octomom locus copy number correlated increasing copy number to both Wolbachia bacterial density and increased pathology. Here we demonstrate that infected fly pathology is not dependent on an increased Octomom copy number, but does strongly correlate with increasing temperature. When measured across developmental time, we also show Octomom copy number to be highly variable across developmental time within a single generation. Using a second pathogenic strain of Wolbachia, we further demonstrate reduced insect lifespan can occur independently of a high Octomom locus copy number. Taken together, this data demonstrates that the mechanism/s of wMelPop virulence is more complex than has been previously described.
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View more >Wolbachia are maternally transmitted intracellular bacterial symbionts that infect approximately 40% of all insect species. Though several strains of Wolbachia naturally infect Drosophila melanogaster and provide resistance against viral pathogens, or provision metabolites during periods of nutritional stress, one virulent strain, wMelPop, reduces fly lifespan by half, possibly as a consequence of over-replication. While the mechanisms that allow wMelPop to over-replicate are still of debate, a unique tandem repeat locus in the wMelPop genome that contains eight genes, referred to as the “Octomom” locus has been identified and is thought to play an important regulatory role. Estimates of Octomom locus copy number correlated increasing copy number to both Wolbachia bacterial density and increased pathology. Here we demonstrate that infected fly pathology is not dependent on an increased Octomom copy number, but does strongly correlate with increasing temperature. When measured across developmental time, we also show Octomom copy number to be highly variable across developmental time within a single generation. Using a second pathogenic strain of Wolbachia, we further demonstrate reduced insect lifespan can occur independently of a high Octomom locus copy number. Taken together, this data demonstrates that the mechanism/s of wMelPop virulence is more complex than has been previously described.
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Journal Title
PLoS Pathogens
Volume
12
Issue
9
Copyright Statement
© 2016 Rohrscheib et al. This is an open
access article distributed under the terms of the
Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any
medium, provided the original author and source are
credited.
Subject
Host-parasite interactions
Microbiology
Immunology
Medical microbiology