Delivering data-driven, field-level decision-support tools for black shank management

Yuan Zeng’s Hatch project emphasizes comprehensive soil testing to build a disease forecasting model, helping growers manage destructive soil-dwelling pathogens.

By Julie Shlisky

Black shank is a disease caused by a destructive oomycete that lives in the soil and affects several economically important crops, including onion, tomato, and tobacco. The disease, caused by a fungus-like pathogen called Phytophthora nicotianae, is particularly challenging because it continues to evolve, becoming capable of infecting previously resistant plant varieties. This challenge is compounded by the impacts of climate change.

Assistant Professor Yuan Zeng designed her Hatch project to develop predictive tools for managing black shank disease. Zeng holds a dual appointment at the School of Plant and Environmental Sciences and the Southern Piedmont Agricultural Research and Extension Center. Her project emphasizes comprehensive soil testing, including pathogen quantification and soil fertility analysis, as the foundation for building a disease forecasting model.

Zeng’s team integrates quantitative, lab-based assays specific to specific pathogen types with real-time environmental soil sensors and detailed soil physicochemical data. These data are used to identify key factors driving black shank disease development. Ultimately, her work aims to provide a data-driven tool to support growers in making informed decisions to manage black shank in their fields.

A major impact of Zeng’s work has been the development of a novel tool: a fluorescent probe-based quantitative PCR assay to quantify levels of this pathogen in field soils. To date, more than 300 soil samples from tobacco-growing regions in Virginia, Kentucky, Georgia, and North Carolina have been submitted to her group for quantification. Results have informed stakeholder decisions on field selection for tobacco cultivation.

Additionally, analysis performed by her team on pathogen isolates from tobacco, potato, and tomato plants suggests that tobacco-associated strains may have evolved from ancestral types that originally infected potato and tomato. Within the group of pathogens infecting tobacco, distinct clustering based on geographic location and specific within-species groups, or races, was observed, indicating potential regional adaptation and race-specific differentiation.

Findings from this project have laid the foundation for new research initiatives that characterize the soil microbiome in tobacco fields with varying levels of black shank disease burden. The project has also led to a collaboration with GoldLeaf Seed Co., focusing on soil testing for a range of soilborne pathogens, further emphasizing the importance of soil testing as a critical component of integrated disease management strategies for stakeholders.