Hybrid metagenome assemblies link carbohydrate structure with function in the human gut microbiome

Area of Science:

• Microbiology
• Metagenomics
• Gut Microbiome Research

Background:

• Gut microbes break down complex carbohydrates indigestible by humans.
• Microbial metabolism of carbohydrates impacts host health.
• Carbohydrate structure's role in shaping gut microbial communities is not fully understood.

Purpose of the Study:

• To investigate how distinct carbohydrate structures influence gut microbial composition.
• To identify specific microbes and their genes involved in carbohydrate degradation.
• To explore species-level dynamics within a model gut microbiome.

Main Methods:

• Utilized a controlled model gut system.
• Fed six structurally diverse carbohydrates to the model.
• Employed hybrid metagenome assemblies to analyze microbial genomes.
• Identified 509 high-quality metagenome-assembled genomes (MAGs).

Main Results:

• Identified bacterial species with starch-binding modules that increased with starch exposure.
• Observed species-level compositional variation in response to different carbohydrates.
• Cataloged microbes from ten bacterial classes and 28 families.
• Linked specific microbial genes to the degradation of particular carbohydrate substrates.

Conclusions:

• Bacterial species possessing starch-binding modules are enriched by starch substrates.
• Hybrid metagenomics enables the discovery of uncultured microbes with specific carbohydrate-degrading functions.
• Carbohydrate structure plays a key role in directing the composition and succession of carbohydrate-degrading gut microbes.