Research

Our group uses Drosophila and its powerful genetics on two main axes of research focusing on:

  1. Drosophila immunity
  2. Drosophila-Spiroplasma interactions: a model of endosymbiosis

1) Drosophila innate immunity

Insects possess efficient mechanisms for detecting and neutralizing microbial infections. The application of Drosophila genetics to deciphering these mechanisms has generated insights into insect immunity and uncovered similarities with mammalian innate immune responses. Our research focuses on understanding mechanisms of microbial infection and corresponding host defense responses in Drosophila using genetic and genomic approaches. Our group employs genetic screens to identify novel factors regulating the immune response of Drosophila. These studies extend our understanding of how the Toll and ImdNF-kB pathways activate antimicrobial defense, as well as how the host recognizes and distinguishes between different microbial pathogens. We are also analyzing the strategies used by entomopathogenic bacteria to subvert the Drosophila innate immune system and have a long-standing interest in the gut immune response.

 
Figure 1. Adult fly injected with GFP expressing bacteria. This mode of infection triggers a systemic immune response consisting of the production of antimicrobial peptides by the fat body, phagocytosis by blood cells and melanization at the site of injury.
Figure 1. Adult fly injected with GFP expressing bacteria. This mode of infection triggers a systemic immune response consisting of the production of antimicrobial peptides by the fat body, phagocytosis by blood cells and melanization at the site of injury.
 
 

2) The Drosophila-Spiroplasma interaction: a model for insect endosymbiosis


Virtually every species of insect harbours facultative bacterial endosymbionts (ex. Wolbachia) that are transmitted from females to their offsprings. These symbionts play crucial roles in the biology of their hosts. Some manipulate host reproduction, for example, by killing the sons of infected females, in order to spread within host populations. Other symbionts protect their hosts against natural pathogens and parasites. However, in spite of growing interest in endosymbionts, very little is known about the molecular mechanisms underlying most endosymbiont-insect interactions. Our laboratory is studying the interaction between Drosophila and its endosymbiont Spiroplasma poulsonii. We are using a broad range of approaches ranging from molecular genetics to genomics to dissect the molecular mechanisms underlying key features of the symbiosis, including vertical transmission, male killing, regulation of symbiont growth, and symbiont-mediated protection against pathogens. We believe that the fundamental knowledge generated by studying the Drosophila-Spiroplasma interaction will serve as a paradigm for other endosymbiont-insect interactions that are less amenable to genetic studies.

 
Figure 2: Spiroplasma colonization of the germline. Spiroplasma uses the yolk uptake machinery to colonize the germline, ensuring vertical transmission. In this photo, Spiroplasma bacteria (stained in red) are colonizing the egg chamber (stained with phalloidin) during vitellogenesis. (Spiroplasma).
Figure 2: Spiroplasma colonization of the germline. Spiroplasma uses the yolk uptake machinery to colonize the germline, ensuring vertical transmission. In this photo, Spiroplasma bacteria (stained in red) are colonizing the egg chamber (stained with phalloidin) during vitellogenesis. (Spiroplasma).