A mutually beneficial physical habitat within Drosophila melanogaster controls the consistent presence of a diverse gut microbiome

Researchers recently announced the foregut creates a specialized environment that captures specific bacteria, keeping them stable in the gut, and Lactobacillus bacteria helps modify this environment to support the colonization of unrelated Acetobacter bacteria.

The research highlights the selective nature of bacterial colonization within Drosophila, the host's role in promoting beneficial bacteria, the potential involvement of the extracellular matrix and the complexity of microbiome assembly, according to Nature Communications. Additionally, it emphasizes the significance of understanding these processes for insights into microbiome function and their potential relevance in other animals, including humans.

The study reveals that certain strains of Drosophila gut bacteria inhabit specific crypt-like furrows within the proventriculus, and this colonization is saturable, implying a limited number of binding sites. This finding demonstrates the selectivity of bacterial colonization within the host.

The study reveals that the proventriculus responds to bacterial colonization through engorgement, which promotes the colonization of bacteria beneficial to the fly. This suggests a mutually beneficial relationship between the host and specific bacterial strains in the gut.

The research speculates about the existence of specific molecules in the proventriculus's extracellular matrix that bind to colonization-competent bacterial strains. This raises questions about the role of these molecules and whether niche cells are involved in their production.

The study proposes a model where the binding of one bacterial strain can lead to structural changes in the niche, allowing for the colonization of other bacterial species. This model illustrates how complex bacterial communities can form and persist in the host's digestive tract, with primary colonizers selecting secondary colonizers.

Dodge, R., Jones, E.W., Zhu, H. et al. A symbiotic physical niche in Drosophila melanogaster regulates stable association of a multi-species gut microbiota. Nat Commun 14, 1557 (2023). https://doi.org/10.1038/s41467-023-36942-x