TY - JOUR
T1 - Intensity of Mutualism Breakdown Is Determined by Temperature Not Amplification of Wolbachia Genes
AU - Rohrscheib, Chelsie E.
AU - Frentiu, Francesca D.
AU - Horn, Emilie
AU - Ritchie, Fiona K.
AU - van Swinderen, Bruno
AU - Weible, Michael W.
AU - O'Neill, Scott L.
AU - Brownlie, Jeremy C.
PY - 2016/9/1
Y1 - 2016/9/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84989953087&partnerID=8YFLogxK
U2 - 10.1371/journal.ppat.1005888
DO - 10.1371/journal.ppat.1005888
M3 - Article
AN - SCOPUS:84989953087
SN - 1553-7366
VL - 12
JO - PLoS Pathogens
JF - PLoS Pathogens
IS - 9
M1 - e1005888
ER -