Rethinking plant disease prevention: lessons from a Tilletia caries soil infection study

Seed coatings can effectively protect plants from diseases that are dually transmitted in seed and soil. However, the reduction of synthetic seed protection products due to environmental concerns necessitates new preventive approaches, including improved disease detection tools. The detection of seed-borne diseases, like Tilletia caries (common bunt), relies on seed health tests and often neglects soil-borne sources. In order to better assess the risk to plant health from soil- versus seed-borne infections of T. caries, we conducted a climate chamber experiment and applied the same disease inoculum (0.1 g teliospores /pot) to wheat seeds or the soil in which they were planted. Based on a common conception that T. caries is primarily seed-borne, we expected higher infection levels from the seed-borne inoculum. Instead, our data revealed that, compared to seed infections, T. caries teliospores in soil resulted in significantly more diseased plants under the same growth conditions. Therefore, T. caries soil-borne outbreaks could also result in substantial crop and quality losses, motivating the project’s next steps to optimize T. caries molecular detection in soil. These results underline the need to develop integrative approaches that extend beyond seed testing and include soil surveillance to prevent potential soil-borne outbreaks.