These few studies dealing with the expression of plant defense reactions in response to inoculation with a protective strain of F. oxysporum do not provide any information about the metabolic pathways triggered by the protective strains. In contrast, most of the recent studies dealing with plant defense induced by pathogenic strains have focused on the metabolic pathways leading to resistance, especially in A. thaliana. Results have shown that A. thaliana resistance to F. oxysporum requires intact ET, JA and SA signaling pathways, these pathways interacting positively with the activation of A. thaliana resistance to F. oxysporum (Berrocal-Lobo & Molina, 2004, 2007; McGrath et al., 2005). To our knowledge, an approach that uses plant mutants defective in different metabolic pathways has not yet been explored in tomato inoculated with protective strains of F. oxysporum.