Frateuria defendens biopesticide for phloem-limited crop pathogens
Endophytic bacterium Frateuria defendens introduced into crop phloem tissue to suppress Liberibacter and phytoplasma diseases. Validated in carrot and potato systems, offering an antibiotic-free, sustainable alternative to conventional pesticide-based management of insect-vectored bacterial pathogens.
Overview
This solution leverages the endophytic bacterium Frateuria defendens (Frd) as a biological control agent against phloem-limited plant pathogens, including bacteria from the genus Liberibacter and phytoplasmas. These pathogens are transmitted by phloem-feeding insects and cause devastating diseases such as zebra chip in potato and carrot yellows, posing serious threats to global food production. Current management options are limited because conventional pesticides fail to reliably control insect vectors and antimicrobial treatments accelerate antibiotic resistance. Frd offers a green, sustainable alternative by colonizing plant vascular tissue and reducing both pathogen titer and disease symptom development.
Technical specifications
Key features:
- Frd is applied as a foliar spray and successfully penetrates plant tissue, reaching both xylem and phloem systems
- Bacterial colonization confirmed via PCR, sequencing, and scanning electron microscopy (SEM)
- Concentrations of 10⁴–10⁵ CFU per mL recovered from surface-sterilized leaves and tubers 11–19 days post-treatment
- Significantly suppresses axillary shoot proliferation symptoms in Liberibacter-infected carrots under natural inoculation conditions
- Mechanism involves interactions between the endophyte, the plant host, and the pathogen to reduce symptom development
- Compatible with multiple potato varieties, with optimization planned across concentrations, application methods, and timing
- Targets reduction of psyllid yellows and zebra chip disease symptoms in potato
Technology readiness level
Proof-of-concept validation has been completed in both carrot and potato systems, with documented pathogen suppression and confirmed endophyte colonization in vascular tissues. The technology is at an early-to-mid stage of development, with planned optimization studies to evaluate efficacy across additional potato varieties and to quantify reductions in Liberibacter titer and disease symptom severity. The research team is seeking funding support for key personnel, growing materials, and molecular diagnostic and imaging supplies to advance toward broader field validation.
About University of California, Riverside
UC Riverside is a comprehensive public research university within the UC system, recognized for translational work and talent development at scale. An on‑campus research and technology park, shared core facilities, and prototype spaces let companies co‑locate and validate new solutions alongside faculty. Partnerships with a medical enterprise and regional hospitals support clinical collaboration, while field sites and an extension network translate research to producers and communities across the region. Faculty secure competitive federal funding from NSF, NIH, DOE, and USDA, complemented by state and industry support. A dedicated technology transfer office streamlines IP, licensing, and startup formation, with incubator programming and flexible lab space for corporate collaborators.
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