Relating Phylogenetic and Functional Diversity among Denitrifiers and Quantifying their Capacity to Predict Community...

Area of Science:

• Microbiology
• Microbial Ecology
• Molecular Ecology

Background:

• Genetic diversity is commonly used as a proxy for microbial diversity.
• The relationship between functional diversity, gene sequence diversity, and community functioning remains unclear.
• Denitrifying bacteria play a crucial role in nitrogen cycling.

Purpose of the Study:

• To analyze the relationships between functional traits, gene sequence similarity, and community functioning in denitrifying bacteria.
• To evaluate different diversity metrics for their ability to infer the functioning of assembled denitrifier communities.
• To determine which diversity proxies best predict microbial community functioning.

Main Methods:

• Assessed functional traits using metabolic profiles (BIOLOG plates) and N2O accumulation patterns.
• Analyzed phylogenetic (16S rRNA gene) and functional (nir gene) marker similarities.
• Calculated various diversity metrics including taxa richness, phylogenetic diversity, and functional diversity (FD).

Main Results:

• Individual strain 16S rRNA gene sequence variation weakly correlated with metabolic patterns and not N2O accumulation.
• N2O accumulation was correlated with nitrite reductase (nirS) amino acid similarity, but not nirK.
• Functional diversity (FD) based on N2O accumulation patterns explained 23-42% of variation in denitrification, outperforming phylogenetic diversity and metabolic profile-based FD.

Conclusions:

• Functional diversity, specifically related to N2O accumulation patterns, is a better predictor of denitrifier community functioning than genetic markers or metabolic profiles.
• Community niche, a measure of FD based on N2O accumulation, was the most effective metric for predicting community functioning.
• Resource complementarity is important for bacterial community functioning.