Novel microbial fungicide using pseudomonas protegens PS11 to control fungal infections in tomato crops

Overview

This solution introduces a novel microbial fungicide based on a native bacterial strain, Pseudomonas protegens (PS11), isolated and characterized through 16S sequencing. The strain demonstrated 90-100% inhibitory activity against two major tomato pathogens, Sclerotinia sclerotiorum and Botrytis cinerea, in laboratory antagonistic assays. Beyond disease suppression, PS11 exhibits multiple plant growth-promoting traits, offering a dual benefit of pathogen control and improved crop performance. The technology targets greenhouse and open-field tomato production, where fungal diseases cause significant yield losses, and aims to reduce reliance on chemical fungicides.

Technical specifications

Key features:

• Pseudomonas protegens strain PS11 isolated from native soil and identified via 16S rRNA sequencing
• Broad-spectrum antifungal activity achieving 90-100% inhibition of S. sclerotiorum and B. cinerea in dual-culture plate assays on PDA medium
• Plant growth-promoting attributes including phosphate solubilization, siderophore production, nitrogen fixation, and indole-3-acetic acid (IAA) production
• Planned formulation strategies using biochar carriers and bacterial nano-emulsions in lemongrass essential oil (which does not inhibit PS11 viability)
• Targeted application for tomato cultivars under greenhouse and field conditions

Validation status:

• In vitro antagonism confirmed through replicated plate assays (n=12) with negative controls
• Plant growth-promoting traits verified through growth on nitrogen-free medium, phosphate solubilization assays, and siderophore formation tests

Technology readiness level

The technology is currently at an early-to-mid stage of development. The core biological mechanism has been validated in vitro, confirming both antifungal efficacy and plant growth-promoting capabilities of the PS11 strain. Future validation will focus on greenhouse trials using two formulation approaches (biochar and nano-emulsion in lemongrass essential oil) to evaluate disease severity reduction in tomato cultivars, followed by field studies. Additional investigations will assess the impact of PS11 application on soil microbial diversity, plant immunity gene expression, and volatile compound production. Further development, including formulation optimization, scale-up fermentation, regulatory assessment, and multi-location field trials, is needed before commercial deployment.