Heidi Kaech1,2, Alice B Dennis3, Christoph Vorburger4,5. 1. Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland. kaechh@outlook.com. 2. D-USYS, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland. kaechh@outlook.com. 3. Institute of Biochemistry and Biology, University Potsdam, Potsdam, Germany. 4. Aquatic Ecology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland. 5. D-USYS, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland.
Abstract
BACKGROUND: Secondary endosymbionts of aphids provide benefits to their hosts, but also impose costs such as reduced lifespan and reproductive output. The aphid Aphis fabae is host to different strains of the secondary endosymbiont Hamiltonella defensa, which encode different putative toxins. These strains have very different phenotypes: They reach different densities in the host, and the costs and benefits (protection against parasitoid wasps) they confer to the host vary strongly. RESULTS: We used RNA-Seq to generate hypotheses on why four of these strains inflict such different costs to A. fabae. We found different H. defensa strains to cause strain-specific changes in aphid gene expression, but little effect of H. defensa on gene expression of the primary endosymbiont, Buchnera aphidicola. The highly costly and over-replicating H. defensa strain H85 was associated with strongly reduced aphid expression of hemocytin, a marker of hemocytes in Drosophila. The closely related strain H15 was associated with downregulation of ubiquitin-related modifier 1, which is related to nutrient-sensing and oxidative stress in other organisms. Strain H402 was associated with strong differential regulation of a set of hypothetical proteins, the majority of which were only differentially regulated in presence of H402. CONCLUSIONS: Overall, our results suggest that costs of different strains of H. defensa are likely caused by different mechanisms, and that these costs are imposed by interacting with the host rather than the host's obligatory endosymbiont B. aphidicola.
BACKGROUND: Secondary endosymbionts of aphids provide benefits to their hosts, but also impose costs such as reduced lifespan and reproductive output. The aphid Aphis fabae is host to different strains of the secondary endosymbiontHamiltonella defensa, which encode different putative toxins. These strains have very different phenotypes: They reach different densities in the host, and the costs and benefits (protection against parasitoid wasps) they confer to the host vary strongly. RESULTS: We used RNA-Seq to generate hypotheses on why four of these strains inflict such different costs to A. fabae. We found different H. defensa strains to cause strain-specific changes in aphid gene expression, but little effect of H. defensa on gene expression of the primary endosymbiont, Buchnera aphidicola. The highly costly and over-replicating H. defensa strain H85 was associated with strongly reduced aphid expression of hemocytin, a marker of hemocytes in Drosophila. The closely related strain H15 was associated with downregulation of ubiquitin-related modifier 1, which is related to nutrient-sensing and oxidative stress in other organisms. Strain H402 was associated with strong differential regulation of a set of hypothetical proteins, the majority of which were only differentially regulated in presence of H402. CONCLUSIONS: Overall, our results suggest that costs of different strains of H. defensa are likely caused by different mechanisms, and that these costs are imposed by interacting with the host rather than the host's obligatory endosymbiontB. aphidicola.
Authors: Alice M Laughton; Justine R Garcia; Boran Altincicek; Michael R Strand; Nicole M Gerardo Journal: J Insect Physiol Date: 2011-03-23 Impact factor: 2.354
Authors: Nicole M Gerardo; Boran Altincicek; Caroline Anselme; Hagop Atamian; Seth M Barribeau; Martin de Vos; Elizabeth J Duncan; Jay D Evans; Toni Gabaldón; Murad Ghanim; Adelaziz Heddi; Isgouhi Kaloshian; Amparo Latorre; Andres Moya; Atsushi Nakabachi; Benjamin J Parker; Vincente Pérez-Brocal; Miguel Pignatelli; Yvan Rahbé; John S Ramsey; Chelsea J Spragg; Javier Tamames; Daniel Tamarit; Cecilia Tamborindeguy; Caroline Vincent-Monegat; Andreas Vilcinskas Journal: Genome Biol Date: 2010-02-23 Impact factor: 13.583