Genotype-Specific Rhizosphere Microbiome Assembly Mediates Biochar-Induced Salt Tolerance in Sorghum

Area of Science:

• Agricultural Science
• Microbiology
• Soil Science

Background:

• Salt stress negatively impacts crop yields, particularly in sensitive sorghum genotypes.
• Biochar's role in modulating plant-microbe interactions under stress is not fully understood.
• Sorghum genotypes exhibit inherent differences in rhizosphere microbiome assembly.

Purpose of the Study:

• To investigate how biochar influences genotype-specific rhizosphere microbiome assembly in sorghum under salt stress.
• To elucidate the mechanisms by which biochar enhances salt tolerance in different sorghum varieties.
• To identify key microbial taxa and soil properties modulated by biochar.

Main Methods:

• Salt stress applied to salt-sensitive (HN16) and salt-tolerant (JZN) sorghum genotypes with and without biochar.
• Soil physicochemical properties (EC, SOM, pH) analyzed.
• Rhizosphere microbial communities characterized using 16S rRNA gene sequencing.
• Microbial co-occurrence networks constructed and analyzed.

Main Results:

• Biochar application reduced soil electrical conductivity and increased soil organic matter.
• Distinct, genotype-specific microbial communities were enriched by biochar, including stress-resistant taxa.
• Salt-sensitive HN16 recruited *Sporosarcina*, while salt-tolerant JZN enriched *Salinimicrobium*.
• Biochar modulated soil pH and SOM, driving microbial community divergence and enhancing plant biomass.

Conclusions:

• Biochar enhances sorghum salt tolerance primarily by facilitating the deterministic assembly of genotype-specific, functional rhizosphere microbiomes.
• Biochar acts as a precision tool for rhizosphere engineering, optimizing plant-microbe interactions for salinity resilience.
• This study provides a genotype-aware foundation for sustainable agriculture and enhanced crop performance under saline conditions.