Host immunogenetic variation and gut microbiome functionality in a wild vertebrate population

Area of Science:

• Immunogenetics
• Microbiome Research
• Evolutionary Biology

Background:

• The gut microbiome (GM) is crucial for host health and influenced by host immunogenetics.
• Previous research has not explored the impact of Major Histocompatibility Complex (MHC) genes on GM functionality in wild populations.

Purpose of the Study:

• To investigate the effects of MHC genes on the taxonomy and functionality of the gut microbiome in a wild population of Seychelles warblers.
• To assess the relationship between MHC variation and GM composition and function using shotgun metagenomics.

Main Methods:

• Shotgun metagenomics was employed to analyze the gut microbiome.
• The study focused on a natural population of Seychelles warblers (Acrocephalus sechellensis).
• Host immunogenetic data, specifically MHC genes, were correlated with GM data.

Main Results:

• MHC-II diversity correlated with changes in specific bacterial abundances (Lactococcus lactis, Staphylococcus lloydii).
• MHC-I allele (Ase-ua 7) was linked to alterations in Enterococcus casselifavus, Gordonia sp OPL2, Escherichia coli, and Vulcaniibacterium thermophilum.
• Increasing MHC-I diversity was associated with enhanced microbial defense genes and reduced microbial metabolism genes, alongside more fragmented GM networks.

Conclusions:

• MHC variation, particularly MHC-I, significantly shapes both gut microbiome taxonomy and function in wild vertebrates.
• In Seychelles warblers, increased MHC-I diversity leads to a trade-off: enhanced microbial defense at the expense of reduced GM metabolic capacity.
• This study provides insights into the costs and benefits of microbiome health and the co-evolution of the GM and immune system.