Catechol-induced resistance of tomato plants to Fusarium wilt

Treatment of susceptible tomato plants with catechol prevented disease symptom expression after infection by Fusarium oxysporum f. sp. lycopersici. A marked accumulation of total phenols was observed in the catechol-treated plants. Though the treatment changed peroxidase and polyphenoloxidase activity, no changes appeared in their isozyme patterns. The pathogen was recovered from both inoculated-susceptible and catechol-treated tomato stem sections. It is suggested that the catechol treatment renders the susceptible plants symptomless carriers. The mechanism of this acquired resistance is discussed.