VIEW ARTICLE

Physiology and Biochemistry

Effect of Heat-Induced Susceptibility of Tobacco to Black Shank on Protein Content and on Activity of Peroxidases. G. E. Sanden, Former NSF Fellow, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, The senior author is now Associate Professor of Plant Pathology, Northwest Area Extension Office, Kansas State University, Colby, KS 67701; L. D. Moore, Associate Professor of Plant Pathology, Department of Plant Pathology and Physiology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061. Phytopathology 68:1164-1167. Accepted for publication 15 February 1978. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1164.

When tobacco plants of cultivars Coker 187 (resistant) and Virginia Gold (susceptible) were immersed in a water bath at 50 C for 1 min and inoculated with Phytophthora parasitica var. nicotianae, disease severity of both cultivars was increased up to 100% compared with nontreated controls. In root tissue, the protein concentration significantly decreased as disease severity increased in both cultivars. Disease susceptibility was not correlated with levels of peroxidase activity in extracts from both cultivars. The heat treatment, however, induced four distinct peroxidase bands in noninoculated and inoculated Coker 187 roots after 1 hr and 10 days, as shown by disc electrophoresis. These bands were not present in gels of nonheated Coker 187 root extracts.