Disease signatures in whole plants and callus culture of Arabidopsis thaliana infected with the fungal plant pathogen Fusarium graminearum

Abstract There is a growing need for scalable and high-throughput model systems to study plant-pathogen interactions and fungal secondary metabolite production. This research addresses that need by exploring the use of callus culture as a proxy for whole-plant infection dynamics and mycotoxin biosynthesis. Both callus and intact Arabidopsis thaliana plants were inoculated with the fungal pathogen, Fusarium graminearum. Disease progression in plants was evaluated using a visual Fusarium-Arabidopsis Disease (FAD) rating system, while ergosterol, a marker of fungal biomass, was quantified in callus. The mycotoxin, deoxynivalenol, (DON) was measured in both plants and callus. Three A. thaliana accessions with known differences in susceptibility were assessed at 7, 14, and 21 days post-inoculation (DPI). In all greenhouse experiments, inoculated plants exhibited symptoms and signs of infection including mycelial growth, drying, and constriction. The three A. thaliana accessions varied significantly in mean FAD ratings ( P = 0.03), when controlling for timepoint and experiment. DON was detected in flower and seed samples from infected A. thaliana plants. Inoculated calli exhibited symptoms of infection, and DON was measured in some but not all samples. Inconsistent DON detection may reflect detoxification by other fungi or the plants themselves. Mean ergosterol concentrations varied significantly across callus of different accessions ( P = 0.02), when controlling for timepoint and experiment. These findings highlight distinctions in disease markers based on accession-specific susceptibility and time post-inoculation. Collectively, the results support the potential of callus culture as a simplified yet informative system for studying plant-pathogen interactions and developing phytosensors for fungal pathogen detection in the future.