Correlation between cell wall-degrading enzymes in wheat leaves infected by Septoria tritici and disease severity

Investigation of enzyme activity in extracts from wheat leaves inoculated with Septoria tritici revealed activity of the following enzymes: xylanase, cellulase, protease, and alpha-amylase. Levels of xylanase, protease, and cellulase activities were closely correlated (P > 0.05) to fungal antigens as measured by ELISA and visual disease data on infected leaves from greenhouse experiments and field trials in 2002 and 2003. For the tested wheat cultivars, levels of these three enzymes also showed a good correlation (R = 0.65-0.97) with susceptibility ratings from the Bundessortenamt (Federal Office of Plant Variety) recommended cultivar list, which was based on visual assessment. Protease, xylanase, and cellulase are suggested to have a role in plant pathogenesis by S. tritici. Enzyme activity may serve as a measurement of disease severity for assessing the range of susceptibility of wheat cultivars to S. tritici.