Induction and resistance against Fusarium wilt disease of tomato by using sweet basil (Ocimum basilicum L) extract

Abstract

The antifungal activity of Ocimum basilicum (sweet basil) extract against Fusarium oxysporum f. sp. lycopersici race 3 the causal agent of tomato wilt and its ability in inducing disease resistance were studied in vivo using seed-soaking treatment before sowing. Plants were harvested at 45 and 105 d (vegetative and flowering stages) after sowing. Treatment with O. basilicum extract decreased the disease incidence from 94.70 to 18.00%. Results revealed that growth parameters and photosynthetic pigments were markedly inhibited in tomato plants in response to Fusarium wilt disease, whereas the contents of non-enzymatic and enzymatic antioxidants were increased as compared with healthy control plants. Moreover, presoaking in basil extract enhanced all the mentioned parameters in both healthy and infected plants. SDS-PAGE analysis of tomato leaves revealed that seed treated with basil extract resulted in an induction of novel protein bands during the vegetative stage. These new proteins were not detected in untreated healthy or infected control plants. Electrophoretic studies of polyphenol oxidase, esterase and malate dehydrogenase isoenzymes showed wide variations in their intensities and densities among all treatments. It seems that O. basilicum extract was able to enhance the biological control of Fusarium wilt disease of tomato.