Bacterial population-level trade-offs between drought tolerance and resource acquisition traits impact decomposition

Area of Science:

• Microbial ecology
• Environmental microbiology
• Genomics

Background:

• Microbes are essential for ecosystem functions like decomposition.
• Environmental stressors, such as drought, can alter microbial communities and their functions.
• Understanding the mechanisms linking microbial traits to ecosystem processes under stress is crucial.

Purpose of the Study:

• To investigate how drought stress affects bacterial genomic traits and decomposition rates.
• To test the hypothesis that genome-scale trade-offs reduce decomposition capacity under drought.
• To determine if population-level trade-offs scale up to impact community traits and ecosystem functions.

Main Methods:

• Utilized a leaf litter model system over 18 months.
• Applied drought as an environmental stressor.
• Analyzed bacterial genomic traits using metagenome-assembled genomes.
• Assessed decomposition rates and community shifts.

Main Results:

• Drought-tolerant bacterial populations showed heightened stress tolerance mechanisms, indicated by increased gene copy numbers.
• A subset of drought-affected populations exhibited reduced carbohydrate-active enzyme genes, suggesting decreased decomposition capabilities.
• Community succession and taxonomic shifts were observed, driving trait trade-offs.
• Overall decomposition rates and litter decay were reduced under drought conditions.

Conclusions:

• Genome-scale trait trade-offs in soil bacteria under drought stress can impair decomposition.
• Population-level changes in bacterial traits scale up to affect ecosystem functions.
• A trait-based approach reveals the ecological consequences of microbial responses to environmental stressors.