Behind Taxonomic Variability: The Functional Redundancy in the Tick Microbiome

Area of Science:

• Microbiology
• Ecology
• Genomics

Background:

• Tick midgut microbiota composition is well-studied, but functional significance remains underexplored.
• Previous research focused on taxonomic diversity across various tick genera.
• Understanding the functional roles of these microbial communities is crucial for tick biology.

Purpose of the Study:

• To investigate the functional redundancy of the tick microbiome in Ixodes scapularis.
• To compare metabolic profiles between uninfected and Borrelia burgdorferi-infected ticks.
• To assess the impact of infection and developmental stage on microbial functional diversity.

Main Methods:

• Utilized existing 16S amplicon sequence data from three Ixodes scapularis cohorts.
• Employed PICRUSt2 for metabolic profiling and prediction of functional pathways.
• Analyzed taxa contribution and functional similarity using network-based approaches.

Main Results:

• A high percentage (82.7%) of metabolic pathways were shared across all tick samples.
• Borrelia burgdorferi-infected larvae exhibited a reduction in specific functional pathways compared to uninfected nymphs.
• Functional redundancy was observed, with numerous bacterial taxa contributing to single pathways, though reduced in infected larvae.

Conclusions:

• The tick gut microbiota is a self-regulating community with significant functional redundancy.
• Functional traits, rather than just taxonomic profiles, are critical for understanding tick microbiome dynamics.
• Further research should focus on the functional relevance of these pathways for tick fitness and community stability.