Photosynthesis efficiency and relative chlorophyll content in response to the culture filtrates of F. virguliforme. dpi, Days post inoculation. A, Development of SDS foliar chlorosis or necrosis over 3 d in response to phytotoxins produced by F. virguliforme. B, Soybean variety LD01-5907 (wild type) exhibited gradual chlorophyll degradation induced by phytotoxins produced by F. virguliforme. Soybean variety GD2422 (d1d1d2d2 genotype) maintained its relative chlorophyll content (SPAD, Soil-Plant Analyses Development), but the photosynthesis efficiency decreased significantly (one-way ANOVA test, P < 0.01). The vertical and horizontal bars indicate the standard errors of the photosynthesis efficiency and the relative chlorophyll content for each time point and treatment.