Evaluation of Biochemical Changes in Leaves of Tomato Infected with Alternaria Alternata and its Metabolites

The present study was carried out to evaluate the biochemical changes occurring in tomato leaves following treatment with leaf spot disease causing pathogen Alternaria alternata and two of its phytotoxic metabolites. Results revealed that the pathogen treatment caused severe foliar necrosis and by 10th day of treatment almost 3/4th of the leaf area was necrotized. A significant decline in the chlorophyll content was observed in the leaves treated with the pathogen and its metabolites. Reducing sugars showed a visible decline in the treated leaves in comparison to the control leaves. When compared with the control an increase in total soluble protein was observed in leaves treated with the pathogen and its metabolites. In case of phenol, a significant enhancement in phenol content of the pathogen and metabolite treated leaves was observed than the amount detected in control leaves. The results indicate that infection of tomato by the leaf spot pathogen Alternaria alternata and its metabolites causes severe alterations in the amount of various biochemical components.