Effect of 28-homobrassinolide on susceptible and resistant cultivars of tomato after nematode inoculation

In vitro effects of 28-homobrassinolide (HBl) were evaluated on morphological and biochemical parameters of susceptible (Pusa Ruby) and resistant (PNR-7) cultivars of tomato, 5 days after nematode inoculation. In susceptible cultivar, nematode invasion reduced the plant growth while growth was enhanced after brassinosteroid treatment. In case of resistant plants, nematodes were not able to invade the roots and here also, pre-sowing treatment of seeds with HBl further enhanced the growth of plants. An increase in specific activities of antioxidative enzymes (catalase, ascorbate peroxidase, guaiacol peroxidase, glutathione reductase, glutathione peroxidase and superoxide dismutase) was observed in susceptible plants treated with HBl. In resistant cultivar, nematode inoculation increased the specific activities which were further enhanced with HBl treatment. The results obtained in the present study indicated the ameliorative effects on tomato varieties treated with HBl even after nematode stress. Thus, suggesting a possible role of HBl in lessening the oxidative stress generated during nematode invasion and boosting the resistance capacity of plants.