Manure source distance and soil depth: a natural screening system for nutrient-solubilizing bacteria

Area of Science:

• Microbial Ecology
• Soil Science
• Biotechnology

Background:

• Nutrient-solubilizing bacteria (NSB) are crucial for plant nutrient uptake and sustainable agriculture.
• Traditional methods for isolating NSB are often inefficient and lack ecological context.
• Understanding microbial community dynamics in response to environmental gradients is key for bioprospecting.

Purpose of the Study:

• To develop and validate an ecology-driven strategy for isolating nutrient-solubilizing bacteria (NSB).
• To leverage natural manure-soil depth gradients as a screening system.
• To identify NSB with high biofertilizer potential for targeted applications.

Main Methods:

• Implemented a full-factorial sampling design across manure-distance and soil-depth gradients.
• Isolated culturable bacteria using a culture-dependent approach.
• Identified bacteria via 16S rRNA gene sequencing and screened for nitrogen fixation, phosphate solubilization (PS), and potassium solubilization (KS).

Main Results:

• Manure input and soil depth created a heterogeneous soil nutrient landscape, with phosphorus influencing bacterial communities.
• Phosphate-solubilizing bacteria (PSB) were enriched in low-phosphorus habitats, confirming niche-based selection.
• Multifunctional NSB strains (e.g., Klebsiella, Enterobacter) with nitrogen fixation, PS, and KS capabilities were successfully isolated from specific microhabitats.

Conclusions:

• Intersecting manure and soil depth gradients provide a powerful, predictable natural screening system for beneficial bacteria isolation.
• This ecology-driven strategy effectively links microbial ecology to bioprospecting.
• The approach yields a curated library of isolates with defined ecological origins, aiding in customized biofertilizer development and enhancing microbial resource mining for sustainable agriculture.