Root-Exuded Metabolites Recruit Selenium-Transforming Microbiota to Enhance Plant Selenium Acquisition.

Area of Science:

• Agricultural Science
• Microbiology
• Biochemistry

Background:

• Microbial fortification is a key strategy for selenium (Se) biofortification in crops.
• Bacillus cereus SESY was previously identified to enhance Se uptake in Brassica napus.

Purpose of the Study:

• To investigate the mechanism by which B. cereus SESY enhances Se bioavailability in the Brassica napus rhizosphere using multi-omics.
• To identify key microbial and metabolic factors involved in Se biofortification.

Main Methods:

• Integrated multi-omics approach (genomics, metabolomics).
• Microbial inoculation experiments in Brassica napus.
• Analysis of bacterial taxa, gene expression (Se metabolism, motility), and rhizosphere metabolites.
• Correlation analysis between microbial and metabolic factors and Se content.

Main Results:

• B. cereus SESY inoculation significantly increased Se content in Brassica napus roots (42.9%) and shoots (21.5% in calcareous soil; 30.7% in yellow brown soil).
• B. cereus SESY promoted the transformation of residual Se into bioavailable forms and enriched motile, Se-transforming bacteria (e.g., Lysobacter, Rhodanobacter).
• Up-regulation of Se metabolism and bacterial motility genes was observed. Core rhizosphere metabolites (N-formylmethionine, xanthine) correlated with bacterial abundance and available Se. Joint application of metabolites and bacteria increased plant Se content by 144%.

Conclusions:

• A metabolite-mediated microbial network enhances Se mobility and plant uptake in the Brassica napus rhizosphere.
• This study reveals a novel microbiome-driven strategy for effective Se biofortification in crops.