Microbial influence on Drosophila biology
Introduction
Microorganisms can be found virtually everywhere. A large number of microbes live in association with animals, with whom they constantly interact and forge alliances. These microbes, called microbiota, provide the hosts with essential services. Many members of the microbiota are symbionts or stable partners that contribute to improve and optimize many aspects of the host physiology [1]. In the last years, research in host–microbiota interaction has significantly advanced our knowledge of the multitude of traits affected by the complex relationship. Our current understanding of the role of microbiota in animals has largely benefitted from studies on Drosophila melanogaster. Natural populations of D. melanogaster live in constant association with microorganisms inhabiting rotting fruits, including a variety of yeasts and bacteria of the Acetobacteraceae and Lactobacillales taxa [2]. In the laboratory, members from the same families of microbes are also found to be extensively associated with their fly partners and in the food. Therefore, Drosophila serves as an excellent model to study host–microbiota interaction, due to its relatively simple intestinal architecture, its amenability to genetic studies and the ease at raising axenic and gnotobiotic flies [3, 4]. Drosophila has been extensively used both to decipher mechanisms of host–microbe interactions in invertebrates and also as a model for translational research. However, the mechanisms behind the mutual interplay between Drosophila and its microbiota are still not fully understood. In this review, we highlight recent studies demonstrating the diverse impacts of microorganisms on Drosophila physiology and behaviour (Figure 1).
Section snippets
The reciprocal effects of Drosophila/microbiota interaction
It is well acknowledged that commensal microbes enhance Drosophila metabolic capacities, development, immune system, and even affect behaviour [5, 6]. To elucidate the basis of Drosophila response to microbes, a few studies have focused on the effect of microbiota on host's gene expression. The presence of microbiota upregulates gene expression associated with Drosophila gut physiology, tissue homeostasis, immune response, at least partly through the IMD pathway [7, 8, 9]. In particular, Elya
Conclusions
To dissect the essential mechanisms underlying host–microbe interaction, research work has largely simplified the experimental settings by defining microbiota composition and standardizing nutritional input. These studies allowed us to identify several important factors involved in host–microbe relationship, revealing the high complexity of the system and its multifactorial nature. It is now clear that a combination of internal mechanisms, exogenous factors and behavioural strategies likely
Conflict of interest
The authors declare no conflict of interests.
References and recommended reading
Papers of particular interest, published within the period of review, have been highlighted as:
• of special interest
•• of outstanding interest
Acknowledgements
FL lab is supported by an ERC starting grant (FP7/2007-2013-N°309704) and an ANR grant (n°ANR-15-CE14-0028-01), the FINOVI foundation, the ‘Fondation Schlumberger pour l’Education et la Recherche’ and the EMBO Young Investigator Programme. MEM was funded by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement N8659510. The authors would like to thank Dr. Carmine Gioffrè for providing graphical support.
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