Contrasting Infection Strategies in Generalist and Specialist Wasp Parasitoids of Drosophila melanogaster

PLoS Pathogens

Andrew G Clark¹  Shubha Govind¹  Jorge Morales²  Todd A Schlenke³ 

[1] Biology Department, City College and the Graduate Center of The City University of New York, New York, New York, United States of America;Department of Biology, Emory University, Atlanta, Georgia, United States of America;Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America

关键词: Drosophila melanogaster;    Immune response;    Parasitic diseases;    Larvae;    Hemocytes;    Venoms;    Gene expression;    Gene regulation;   

DOI  :  10.1371/journal.ppat.0030158

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Although host–parasitoid interactions are becoming well characterized at the organismal and cellular levels, much remains to be understood of the molecular bases for the host immune response and the parasitoids' ability to defeat this immune response. Leptopilina boulardi and L. heterotoma, two closely related, highly infectious natural parasitoids of Drosophila melanogaster, appear to use very different infection strategies at the cellular level. Here, we further characterize cellular level differences in the infection characteristics of these two wasp species using newly derived, virulent inbred strains, and then use whole genome microarrays to compare the transcriptional response of Drosophila to each. While flies attacked by the melanogaster group specialist L. boulardi (strain Lb17) up-regulate numerous genes encoding proteolytic enzymes, components of the Toll and JAK/STAT pathways, and the melanization cascade as part of a combined cellular and humoral innate immune response, flies attacked by the generalist L. heterotoma (strain Lh14) do not appear to initiate an immune transcriptional response at the time points post-infection we assayed, perhaps due to the rapid venom-mediated lysis of host hemocytes (blood cells). Thus, the specialist parasitoid appears to invoke a full-blown immune response in the host, but suppresses and/or evades downstream components of this response. Given that activation of the host immune response likely depletes the energetic resources of the host, the specialist's infection strategy seems relatively disadvantageous. However, we uncover the mechanism for one potentially important fitness tradeoff of the generalist's highly immune suppressive infection strategy.

【 授权许可】

CC BY