Effects of Citrus Exocortis Viroid Infection on the Peroxidase/IAA-Oxidase System of Gynura aurantiaca and Lycoperszcon esculentum

Summary The peroxidase/indoleacetic acid (IAA) oxidase system of plants of Gynura aurantiaca and Lycopersicon esculentum healthy and infected by citrus exocortis viroid (CEV) was studied. In these hosts, the infection induced an increase of both enzymic activities, when they were measured between 40 and 50 d post inoculation. The analysis of isozyme composition by polyacrylamide gel electrophoresis and specific staining of peroxidase revealed an intensification of most of the zymogram bands as well as the premature appearance of one of the isozymes in the two plants investigated. All the tomato isoperoxidases exhibited IAA-oxidase activity when measured with the oxygen electrode. These resu…