Stepwise Gradient in Fundamental Individualised Niche Differentiation Across Soil Microbiomes.

Area of Science:

• Microbial Ecology
• Genomics
• Environmental Microbiology

Background:

• Individual microbes exhibit varied responses to environmental conditions, but the extent of this niche variation is not well understood.
• Existing research often focuses on community-level responses, potentially masking individual microbial behavior.

Purpose of the Study:

• To quantify the individualised niche variation of soil microbes.
• To investigate the influence of environmental factors, specifically temperature, on microbial niche breadth and overlap.
• To characterize the patterns of niche differentiation across different taxonomic levels.

Main Methods:

• Metagenomic binning was applied to monthly soil samples collected over seasonal cycles.
• The fundamental individualised niche (FIN) was defined using 440,571 genes as dimensions.
• FIN trajectories for archaea and bacteria were traced through warming, cooling, and turning periods.

Main Results:

• Neither mean temperature nor temperature difference significantly affected FIN breadth or overlap.
• A consistent, stepwise gradient of niche differentiation was observed across taxonomic categories.
• Niche overlap was approximately 25% at the interdomain level (Archaea vs. Bacteria), 40% at the interphylum level, and 60% at the interorder level.

Conclusions:

• Microbial niche differentiation is structured by a stepwise gradient rather than direct environmental drivers like temperature.
• This gradient suggests inherent boundaries for niche variation and functional synergy within individual niches.
• The findings provide a framework for understanding ecological carrying capacity and interdomain balance in microbial communities.