Antifungal extracellular metabolites from soil microalgae and cyanobacteria for crop disease control

Overview

This research program investigates soil microalgae and cyanobacteria as natural sources of antifungal metabolites that can combat Fusarium, a destructive fungal pathogen affecting crops such as rice and tomato. The hypothesis is that these photosynthetic microorganisms survive in fungus-rich soils by excreting bioactive compounds that inhibit fungal growth. By isolating and characterizing these extracellular metabolites, the project seeks to establish a foundation for biological fungicide development tailored to sustainable agriculture.

The work addresses a critical need for environmentally friendly alternatives to synthetic fungicides, which face growing resistance and regulatory restrictions. Successful identification of these metabolites could enable new biocontrol products, offering farmers effective disease management while supporting soil health and reducing chemical inputs.

Technical specifications

Research approach:

• Screening of 5 microalgae and 5 cyanobacteria strains isolated from soil for resistance to Fusarium
• Isolation and molecular identification of Fusarium strains from infected rice plants, followed by pathogenicity testing
• Physical and chemical characterization of soil samples to understand the environmental context
• Selection of the 3 most resilient strains capable of thriving in Fusarium-contaminated soil
• Separation, characterization, and identification of extracellular metabolites, including potential polysaccharides, proteins, lipids, and phenolic compounds
• Transcriptomic analysis to identify overexpressed biosynthetic pathways during antifungal metabolite production
• Greenhouse validation in rice plants, evaluating disease control efficacy and yield impact after inoculation with selected strains

Technology readiness level

The research is at an early-to-mid stage of development. Prior published work has demonstrated antifungal activity of cyanobacteria and microalgae biomass extracts against Fusarium in vitro and in rice and tomato systems. The current proposal advances this foundation by focusing specifically on soil-adapted strains and their excreted metabolites rather than whole-cell extracts. The project moves from laboratory screening and metabolite identification toward greenhouse validation in rice plants, representing a progression from proof-of-concept toward applied agricultural use. Further field validation and product formulation would be required before commercial deployment.