Pathogen impact on the activity dynamics of potato suspension cells extra-cellular peroxidase

Changes in the activity of extracellular peroxidases were measured in cell suspension cultures of potato infected by Clavibacter michiganensis subsp. sepedonicus (Spieck. et Kotth.) Skapt et Burkh. The total extracellular peroxidases activity of the resistant potato variety was higher than that of the sensitive variety both before and after infection. The enzyme of the resistant variety had a pH optimum of 6.2, while that of the sensitive variety was 5.4. Extracellular peroxidases of the sensitive potato variety were activated 10 minutes after infection, and displayed highest activity 1.5-2 hours later. In the resistant variety, peroxidase activity rose sharply in the first minutes of infection, and second peak of activity occurred 1.5-2 hours later. The increase of extracellular peroxidases activity of the sensitive potato variety under pathogenesis is connected with the change of genome expression and synthesis of proteins. The increase of enzyme activity of resistant potato variety in the first moments of infection is not related to proteins synthesis and is apparently conditioned by the change of kinetic parameters.