70 Oral - Immunity and Microbiome
Friday April 08, 9:30 AM - 9:45 AM

Authors:
Ren Dodge ¹; Eric Jones ^7,2; Haolong Zhu ^1,3; Benjamin Obadia ⁵; Chenhui Wang ¹; Andrés Aranda-Díaz ⁴; Kevin Aumiller ^1,3; Zhexian Liu ³; Marco Voltolini ⁸; Eoin Brodie ⁷; Kerwyn Casey Huang ^4,9; Jean Carlson ²; David Sivak ⁷; Allan Spradling ^1,3,6; Will Ludington ^1,3

Affiliations:
1) Carnegie Institute of Washington; 2) University of California, Santa Barbara, CA; 3) Department of Biology, Johns Hopkins University; 4) Department of Microbiology and Immunology, Stanford University School of Medicine; 5) Molecular and Cell Biology Department, University of California; 6) Howard Hughes Medical Institute; 7) Simon Frasier University, Burnaby, BC; 8) Lawrence Berkeley National Lab; 9) Chan Zuckerberg Biohub

Keywords:
m. microbiome; m. adaptation

Animal guts are colonized by a complex community of host-specific commensal bacteria that is relatively stable over time within an individual and can have life-long effects on health. The microbiome is established and maintained in the face of daily fluctuations in diet, invasion by pathogens, and disruptions by antibiotics. Many gut resident bacteria localize to specific regions of the gut that correspond to chemical environments matching the specific species’ metabolism. Certain probiotic species, namely Lactobacilli, additionally make physical attachments with host mucus, stabilizing their colonization. A key gap in our knowledge is how the host constructs microenvironments that promote colonization by specific multispecies communities of bacteria. Here, we show that a physical niche exists within the proventriculus region of the Drosophila foregut that selectively binds bacteria with exquisite strain-level specificity. Using gnotobiotic flies, microscopy, and microbial population kinetics we found that primary colonizers saturate the niche and exclude secondary colonizers of the same strain. Conversely, initial colonization by Lactobacillus physically remodels the niche to favor secondary colonization by another commensal, Acetobacter. Our results provide a mechanistic framework for understanding the establishment and stability of a multispecies intestinal microbiome. We anticipate this model will form the basis for dissecting the host genetics of an intestinal niche as well as for the discovery of similar niches in Drosophila and other animals, including humans.