Detection of Cutinases and Pectic Enzymes During Infection of Tomato byPseudomonas syringaepv.tomato

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Abstract
Cutinolytic and pectinolytic activities were detected in leaves of either susceptible or resistant tomato cultivars within 48 h after infection with P. syringae pv. tomato. These activites 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 partialy 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 h of infection. The pathogen-produced cutinases and pectic enzymes may be involved in the primary stages of disease development in tomato cultivars susceptible to bacterial speck.