Lactobacilli-Host mutualism: "learning on the fly"

Abstract

Metazoans establish with microorganisms complex interactions for their mutual benefits. Drosophila, which has already proven useful host model to study several aspects of innate immunity and host-bacteria pathogenic associations has become a powerful model to dissect the mechanisms behind mutualistic host-microbe interactions. Drosophila microbiota is composed of simple and aerotolerant bacterial communities mostly composed of Lactobacillaceae and Acetobactereaceae. Drosophila mono- or poly-associated with lactobacilli strains constitutes a powerful model to dissect the complex interplay between lactobacilli and host biologic traits. Thanks to the genetic tractability of both Drosophila and lactobacilli this association model offers a great opportunity to reveal the underlying molecular mechanisms. Here, we review our current knowledge about how the Drosophila model is helping our understanding of how lactobacilli shapes host biology.

Figure 1

Functional impact of commensal lactobacilli on Drosophila biology. Strains of L. plantarum can be true mutualists and impact different aspects of host biology: mating preferences, gut epithelial homeostasis, protection against enteric infection, nutrient allocation and metabolism. During larval stages it promotes systemic growth. Depending on the strain and host genetic background, L. brevis is a mutualist of pathobiont, which interferes with host metabolism and/or induces chronic inflammation and epithelial cell death.