Novel genetic resistance sources in tomato against verticillium dahliae race 2 and race 3
Research program identifying and characterizing novel single-gene resistance sources in tomato against Verticillium dahliae races 2 and 3, using genome-wide association studies and pathogen effector discovery to enable breeding of disease-resistant elite cultivars.
Overview
Verticillium dahliae is a soil-borne fungal pathogen that causes significant yield losses in tomato and other crops. This research program has identified two novel genetic resistance sources against races 2 and 3 of V. dahliae—one in cultivated tomato (Solanum lycopersicum) and another in the wild relative S. chilense. The team is using recombinant inbred lines (RILs) developed from resistant hybrids to map resistance genes through genome-wide association studies, while simultaneously sequencing pathogen isolates to identify secreted effectors responsible for race-specific virulence. The ultimate goal is to introgress these resistance genes into elite tomato cultivars to provide durable, broad-spectrum protection against Verticillium wilt.
Technical specifications
Resistance sources and genetic basis:
- Race 2 resistance discovered in three tomato hybrids (Aibou, GBK, and Bowman), showing a 3:1 resistant-to-susceptible segregation ratio indicating a single dominant resistance gene
- Novel race 3 resistance identified in a S. chilense line, currently being characterized through RNA-seq analysis
- RILs developed from race 2 resistant cultivars are at the F4 stage, with phenotyping performed at every generation to ensure homozygosity
Pathogen characterization:
- Sequenced isolates of races 1, 2, and 3 of V. dahliae used for host resistance screening
- Discovery of secreted effectors responsible for race-specific phenotypes through pathogen genome sequencing
- Host-pathogen interaction matrix built from sequenced resistant and susceptible tomato lines against sequenced V. dahliae isolates
Validation methodology:
- Resistance confirmed by root-dip inoculation in conidia suspension at 10^7 conidia/mL
- Foliage rated for V. dahliae-specific symptoms post-inoculation
- Extensive phenotyping completed for race 2 resistance confirmation
- Phylogenetic and race-specific signatures in isolates being prepared for publication
Technology readiness level
The resistance sources have been identified and genetically characterized at the population level, with RILs in advanced generations (F4). The team is currently transitioning from mapping to gene discovery, with short-term plans to identify candidate resistance genes through RNA-seq and whole genome sequencing, followed by gene knockout validation. Long-term objectives include introgression of these novel resistance genes into elite tomato cultivars for commercial deployment. The pathogen side of the research is similarly advanced, with race-specific effector discovery underway to understand the molecular basis of resistance-breaking.
About North Carolina State University
North Carolina State University is a large, comprehensive public land‑grant research university in Raleigh. Its on‑campus research and technology park co‑locates corporate R&D groups, government partners, and faculty labs, enabling shared facilities, prototyping, and agile contracting. Located in North Carolina’s Research Triangle, partners tap a dense regional ecosystem while engaging through a statewide extension network and a mature co‑op program that deliver field deployment and workforce pipelines. Multiple pilot and demonstration facilities support scale‑up and validation toward pre‑commercial readiness. Research is supported by competitive funding from major federal agencies, including NSF, USDA, DOE, and DOD, and a dedicated technology transfer office with clear IP pathways helps accelerate commercialization.
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