Work

Exploring the bioactive potential of rhizospheric Streptomyces clavuligerus against Macrophomina phaseolina, an incitant of groundnut dry root rot disease

Year: 2025

Type: article

Abstract: Dry root rot caused by Macrophomina phaseolina is the most destructive soil-borne fungal disease that severely hampers groundnut production. This study investigated the multifaceted biocontrol and plant growth-promoting potential of rhizospheric Streptomyces spp., focusing on the strain Streptomyces clavuligerus GRS-8. In vitro dual culture assays revealed that GRS-8 exhibited the highest antifungal activity, inhibiting 76.50 % of M. phaseolina mycelial growth. The strain also produced key metabolites, including indole-3-acetic acid, siderophores, and hydrolytic enzymes, contributing to plant growth promotion and defense priming. In silico molecular docking identified quininone oxime as a potent bioactive compound with high binding affinity to five virulence-associated proteins of M. phaseolina. Molecular dynamics simulations confirmed the structural stability of the lipase-quininone oxime complex, supporting its potential as a fungal inhibitor. Under protected cultivation, the combined application of GRS-8 liquid formulation via seed treatment, basal application, and soil drenching significantly reduced dry root rot incidence by 73.10 % and enhanced the activity of host defense enzymes. These findings highlight the dualistic mechanism of S. clavuligerus GRS-8 involving direct antifungal action and host defense induction, underscoring its potential as a promising biocontrol agent for sustainable groundnut cultivation.

Source: Microbial Pathogenesis

DOI: 10.1016/j.micpath.2025.108093