Hosts and Commensal Bacteria Synergistically Antagonize Opportunistic Pathogens at the Single-Cell Resolution

Area of Science:

• Microbiology
• Host-microbe interactions
• Systems biology

Background:

• Microbial communities are complex, with poorly understood regulatory mechanisms.
• Host-microbe and microbe-microbe interactions are crucial for ecosystem dynamics.

Purpose of the Study:

• To investigate the molecular mechanisms of a three-species interaction involving Drosophila, Lactiplantibacillus plantarum, and Serratia marcescens.
• To elucidate how host-microbe alliances influence competition and colonization resistance.

Main Methods:

• Utilized an integrated three-species model system (Drosophila, L. plantarum, S. marcescens).
• Analyzed transcriptional reprogramming in larvae and bacterial populations.
• Examined population dynamics and virulence evolution at single-cell resolution.

Main Results:

• Drosophila facilitates L. plantarum growth, conferring colonization resistance against S. marcescens.
• S. marcescens employs adaptive strategies, including sensing lactate and evolving virulence heterogeneity.
• L. plantarum exhibits broadened lactate generation heterogeneity to support the host alliance.

Conclusions:

• Host-commensal-pathogen symbiosis involves intricate regulatory networks and adaptive evolution.
• Single-cell resolution reveals mechanisms of bacterial community manipulation and resistance heterogeneity.
• Findings advance fundamental concepts in microbial ecology and host-microbe interactions.