Biological control of Fusarium oxysporum f. sp. lycopersici and induction of defensive enzyme of phenylalanine ammonialyse in tomato by Trichoderma and Bacillus antagonist isolates

Background & Fusarium wilt disease is one of the limiting factors of tomato production in most countries, especially in Iran. Considering the malicious effect of chemicals on health, the study on the alternatives for disease controlling is important. This study aimed to evaluate the ability of Trichoderma and Bacillus isolates on biological control of Fusariumoxysporum f. sp. lycopersici.
Materials & The inhibitory effects of  Trichoderma and Bacillus isolates against Fusarium were evaluated on PDA. The ability of the colonization of these antagonists was also examined. The effect of separate and combined application of the antagonists isolates against Fusarium vascular wilt disease severity index and some growth factors of tomato were determined. Also, the potential of these isolates on the induction of phenylalanine ammonlyase was measured in seedlings infected with Fusarium.
The biocontrol agents showed different levels of inhibition of Fusarium growth. The Trichoderma isolates were more successful with a high inhibitory effect (72.06% and 69.16%). These isolates were also powerful colonizers of the pathogen. The disease severity was affected by the antagonists at different levels. Separate and combined treatments of Trichoderma isolates were more effective in the reduction of the disease severity and improving the growth factors. The activity of phenylalanine ammonialyas increased in the plants treated with Trichoderma isolates compared to control treatment (Fusarium). The combined application of these isolates was more effective than the separate using of them on the induction of the enzyme.
The investigated Trichoderma isolates were successful in controlling the pathogen. Therefore, the use of these isolates as agents with multiplier effects can be effective in biocontrol of tomato Fusarium wilt.