Selective enrichment platform for beneficial bacterial endophyte bioinoculants to reduce chemical fertilizer use

Overview

This solution offers a highly selective enrichment methodology for isolating beneficial bacterial endophytes that can serve as next-generation bioinoculants. By leveraging the protected and stable niche of the plant endosphere, the approach targets generalist microorganisms that efficiently colonize internal root tissues, tolerate abiotic stresses such as salinity and nutrient limitation, and coexist as cooperative consortia. The ultimate goal is to reduce dependence on chemical fertilizers while maintaining or improving crop performance, addressing a critical need in sustainable agriculture.

Technical specifications

Enrichment methodology:

• Serial re-inoculation across multiple plant generations using endosphere macerates from the previous generation
• Initial generation grown in highly bio-diverse wild soil to maximize microbial starting diversity
• Selective pressure applied through targeted abiotic stress conditions (e.g., saline stress, limited nutrient availability)
• Microbial community composition tracked after each re-inoculation step via next-generation sequencing (NGS)

Validation outcomes:

• Pilot experiment across five plant generations under saline stress confirmed enrichment of Stenotrophomonas and Achromobacter genera, both previously associated with salinity tolerance
• Future validation will assess keystone co-occurring endophytes for plant-beneficial traits across multiple combinations and fertilization regimes
• Best-performing consortia will be selected for development as commercial bioinoculants

Key advantages:

• Selects for endophytes that are well-adapted to specific stress conditions rather than relying on random screening
• Identifies cooperative consortia rather than single strains, improving field robustness
• Compatible with reduced fertilizer regimes, supporting sustainable intensification

Technology readiness level

The enrichment methodology has been validated in a pilot experiment demonstrating successful selection of stress-adapted endophyte genera under saline conditions across five plant generations. The next stage of validation will extend the approach to nutrient-limited conditions over a one-year experimental period, with plans to isolate and characterize keystone endophytes and evaluate consortia performance under varying fertilization practices. The technology is currently at the proof-of-concept to validation stage, with a clear development pathway toward a field-ready bioinoculant product.