Bacillus-based delivery system for plant immunostimulants to protect potato crops
A biocontrol solution using engineered Bacillus subtilis bacteria to deliver plant defense elicitors (StPep1) directly to potato roots. This rhizospheric delivery system enhances resistance to soilborne pathogens including root-knot nematodes and Spongospora subterranea, while inducing systemic resistance in leaves against foliar pathogens like late blight and gray mold.
Overview
This technology leverages engineered beneficial bacteria as a delivery platform for plant immunostimulants, offering a biological alternative to traditional chemical pesticides for potato crop protection. The approach uses Bacillus subtilis engineered to secrete StPep1, a plant defense elicitor peptide, directly into the rhizosphere (the soil region surrounding plant roots). This targeted delivery stimulates the plant's own immune defenses, reducing infection by root-knot nematodes by approximately 50% and limiting plasmodium formation caused by Spongospora subterranea. Beyond root protection, the technology shows potential to trigger induced systemic resistance (ISR), sending defense signals to aerial plant parts and potentially protecting leaves against foliar pathogens such as late blight and gray mold.
Technical specifications
Key features:
- Engineered Bacillus subtilis strains capable of secreting the plant defense elicitor peptide StPep1
- Rhizospheric delivery system that targets immunostimulants directly to the root zone
- Stimulation of defense-related gene expression in potato roots
- Reduction of root galling caused by root-knot nematodes by approximately 50%
- Reduction of plasmodium formation caused by Spongospora subterranea in roots
- Potential to induce systemic resistance (ISR), activating defense gene expression in leaves
- Collection of B. subtilis strains available for screening optimized secretory capacity
- Greenhouse trial validation planned for efficacy against root-knot nematodes
- Pathogenicity tests planned using foliar pathogens causing late blight and gray mold
Technology readiness level
The technology has progressed beyond initial proof-of-concept. Direct application of StPep1 has been validated to enhance resistance of potato roots to root-knot nematodes and other soilborne pathogens. The engineered B. subtilis delivery system has demonstrated significant reduction in root galling and plasmodium formation in roots. Future validation includes screening the B. subtilis strain collection for optimal StPep1 secretion capacity, greenhouse trials to confirm antagonistic effects against root-knot nematodes, and pathogenicity tests to evaluate induced systemic resistance against foliar pathogens. The technology is currently at a stage suitable for collaborative development and further field validation.
About Washington State University
Washington State University is a comprehensive public land‑grant research university serving the state through a multi‑campus system anchored in Pullman. Industry engagement runs through a research and technology park in Pullman, a health sciences campus in Spokane integrated with regional hospitals, and a statewide extension network linking faculty with companies and communities. The Tri‑Cities campus sits minutes from a U.S. Department of Energy national lab, enabling collaborations, shared facilities access, and talent pipelines for regulated sectors. Research is supported by competitive federal funding from agencies such as NSF, NIH, USDA, DOE, and DoD. A dedicated technology transfer office manages IP, licensing, and startup support, complemented by incubator and pilot‑scale resources.
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