Induction of systemic resistance in Lycopersicon esculentum cv. PKM1 (tomato) against Cucumber mosaic virus by using ozone

Studies were undertaken to evaluate ozone (O3) for induction of resistance against Cucumber mosaic virus in Lycopersicon esculentum cv. PKM1 (tomato) plants. Callus induced from tomato leaf explants on Murashige & Skoog's (MS) medium supplemented with benzyladenine (8.82 μM) were treated with different concentrations of ozone T1, T2, T3 and for control (C), filtered air was supplied. Regeneration of shoots was obtained by culturing ozone treated calli on MS medium containing 17.3 μM benzyladenine. The frequency of regeneration of tomato plants from the callus were T1 = 79%, T2 = 61%, T3 = 42%, but for control 90% regeneration was obtained. Regenerated plants were rooted in half strength MS medium supplemented with 10 μM indole-butyric acid and successfully acclimatized. The plants regenerated from ozone treated callus are referred to as T1, T2 and T3 plants, which hold remarkably increased soluble phenolic content compared to the control plants. All the plants were challenged by mechanical inoculation with Cucumber mosaic virus, shows disease incidence ranged from T1 = 32%, T2 = 56%, T3 = 78% and C = 94%. Remarkable increase in activities of salicylic acid (SA), phenylalanine ammonia-lyase (PAL) and peroxidase (POX) were detected after Cucumber mosaic virus inoculation, in foliar extracts of T1 plants than T2 and T3, compared to the control plants.