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Physiology and Biochemistry

Activity, Isozyme Pattern, and Cellular Localization of Peroxidase as Related to Systemic Resistance of Tobacco to Blue Mold (Peronospora tabacina) and to Tobacco Mosaic Virus. X. S. Ye, Department of Plant Pathology, University of Kentucky, Lexington 40546; S. Q. Pan, and J. Ku?. Department of Plant Pathology, University of Kentucky, Lexington 40546. Phytopathology 80:1295-1299. Accepted for publication 4 June 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/Phyto-80-1295.

Stem injection of tobacco cultivar Ky 14 with Peronospora tabacina or leaf inoculation with tobacco mosaic virus induced systemic resistance to both pathogens. The treatment also elicited a systemic increase in peroxidase activity which was positively correlated with induced resistance. Increases were evident in cytosol, intercellular fluid, and cell wall fractions. Upon challenge with P. tabacina, peroxidase activity further increased in the induced plants and remained higher after challenge as compared to the control plants. The isozyme patterns of peroxidases on isoelectric focusing gels showed an increase of two anionic peroxidases. Both peroxidases were positively correlated with induced resistance.