Efficacy of the arbuscular mycorrhizal fungi and Bacillus subtilis for enhancing the metabolic activities and induced resistance in tomato plant when challenged with Fusarium oxysporum

Abstract

The synergistic interaction between two biocontrol agents, an arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and a plant growth-promoting rhizobacterium (Bacillus subtilis) were tested for improving metabolic activities of tomato plants infected by the pathogenic fungus, Fusarium oxysporum f. sp. lycopersici (FOL). The results showed that the treatment with AM fungus, B. subtilis or in combination statistically increased the accumulation of the total soluble sugars, total soluble proteins and total free amino acids, especially when the mixture of two antagonistic strains was used. Elicitation of induced systemic resistance (ISR) by plant-associated biocontrol agents was also demonstrated in this study. Results proved that the colonization of tomato roots by G. mosseae and / or B. subtilis increased the activities of peroxidases, polyphenol oxidases and catalases. In addition, ISR by the two-biocontrol microorganisms leads to accumulation of phenolic compounds inside the plant cells. In addition, SDS-PAGE analysis of proteins revealed that there is an induction of novel proteins as a result of AM fungi and / or bacteria. The obtained results might have contributed to restriction of invasion of F. oxysporum in tomato plants