Melatonin Enhances Peanut Productivity by Enriching Root-Associated Nitrogen-Fixing Bacteria.

Area of Science:

• Agricultural Science
• Plant Biology
• Microbiome Research

Background:

• Melatonin is a phytohormone with potential bio-stimulant properties.
• Its effects on legume root development, yield, and microbiome assembly are not fully understood.

Purpose of the Study:

• To investigate the impact of melatonin seed treatment on peanut (Arachis hypogaea) genotypes.
• To analyze changes in plant productivity and bacterial community composition in response to melatonin.

Main Methods:

• Melatonin seed treatment applied to three peanut genotypes.
• Assessment of root biomass, nodulation, nitrogen balance, and yield traits.
• Amplicon sequencing and co-occurrence network analysis of bacterial communities in root, rhizosphere, and soil.

Main Results:

• Melatonin significantly enhanced root biomass, nodulation, nitrogen balance, and yield, particularly in the Xinbaihua 16 genotype.
• Distinct, genotype- and compartment-specific shifts in bacterial communities were observed, with increased remodeling in root bacteria.
• Melatonin enriched beneficial Proteobacteria, including Rhizobium, Sphingomonas, and nitrogen-fixing symbionts like Pararhizobium and Ensifer.
• Treated roots showed more complex bacterial networks correlated with improved plant traits.

Conclusions:

• Melatonin acts as a dual bio-stimulant and microbiome modulator in peanuts.
• It promotes a functionally enriched and responsive bacterial community, enhancing plant performance and nitrogen acquisition.
• Findings provide a basis for microbiome-informed strategies in peanut crop improvement.