VIEW ARTICLE

Physiology and Biochemistry

Detection of Cutinases and Pectic Enzymes During Infection of Tomato by Pseudomonas syringae pv. tomato. Y. Bashan, Phytobacteriologist, Department of Plant Pathology and Microbiology, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot 76100, Israel, Present address of senior author: Department of Plant Genetics, The Weizmann Institute of Science, Rehovot, Israel; Y. Okon(2), and Y. Henis(3). (2)(3)Associate professor, and professor, respectively, Department of Plant Pathology and Microbiology, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot 76100, Israel. Phytopathology 75:940-945. Accepted for publication 19 January 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/Phyto-75-940.

Cutinolytic and pectinolytic activities were detected in leaves of either susceptible or resistant tomato cultivars within 48 hr after infection with Pseudomonas syringae pv. tomato. These activities markedly decreased at later stages of disease development. The enzymes involved appeared to be constitutive, the activities being only slightly enhanced in the presence of their respective substrates. The cutinolytic activity seemed to be of bacterial origin whereas the pectinolytic (polygalacturonase) activity was partially of bacterial origin and partially evolved from the pathogenic interaction between the pathogen and its host. Inoculation with high numbers of pathogen propagules (10⁹ colony-forming units per milliliter) enhanced cutinolytic and pectinolytic activities and resulted in higher disease severity. Neither proteolytic nor cellulolytic activities seemed to play a role during the first 48 hr of infection. It was suggested that the pathogen-produced cutinases and pectic enzymes may be involved in the primary stages of disease development in tomato cultivars susceptible to bacterial speck.