Nutrient Supply Gradients Modulate Cultivation-Driven Restructuring of Microbial Communities in Desert Soils

Area of Science:

• Microbial Ecology
• Soil Microbiology
• Desert Ecology

Background:

• Cultivation-derived microbial communities are vital for ecological interpretation, especially in nutrient-limited desert soils.
• Understanding how nutrient availability affects microbial recovery during cultivation is crucial for accurate ecological assessments.

Purpose of the Study:

• To investigate the impact of an oligotrophic nutrient gradient on cultivation outcomes and bacterial community structure in Taklimakan Desert soils.
• To compare cultivation-derived bacterial communities with the original soil microbiome under varying nutrient conditions.

Main Methods:

• Utilized three enrichment treatments with decreasing nutrient availability: standard low-nutrient medium (R2A), diluted medium (DR2A), and sterile water.
• Employed amplicon sequencing to analyze bacterial community composition, richness, and diversity.
• Performed beta diversity analysis and co-occurrence network analysis to assess community structure and interactions.

Main Results:

• Cultivation significantly altered community composition, reducing taxonomic richness and diversity compared to the original soil.
• Bacterial communities in cultivation were dominated by a few taxa, unlike the diverse low-abundance lineages in the original soil.
• Nutrient supply intensity modulated the relative abundance of specific taxa at the genus level, but beta diversity showed limited separation among treatments.

Conclusions:

• Cultivation is the primary selective force shaping desert soil bacterial communities recovered through enrichment.
• Nutrient supply intensity acts as a secondary factor influencing taxon-specific enrichment.
• Incorporating nutrient gradients into cultivation strategies is essential for improved ecological interpretation and recovery of oligotrophic microorganisms.