Assessment of Streptomyces isolates of tomato rhizosphere for biocontrol of Fusarium oxysporum f. sp. radicis-lycopersici

Fusarium oxysporum f.sp. radicis-lycopersici (FORL) is a causal agent of tomato crown and root rot, a soil-borne disease of worldwide importance in commercial tomatoes. Actinobacteria, in general, and Streptomyces, in particular, are recognized as plant disease controllers and plant growth promoters due to their wide production of the secondary metabolite. In this study, 740 Actinobacteria isolates were gathered from different tomato farms throughout Fars and Alborz provinces. Enzymes production test, such as protein activity, production of siderophore, demonstrated a positive result for all isolates. The results also showed that the UTS49 cell-free culture in 3 × 10 8 concentration was able to prevent the fungal spore germination with the rate 94%. The results indicated that best biofilm was mostly formed by UTS385, UTS10 and UTS49 isolates. In greenhouse conditions, the results showed that UTS49 caused the reduction of the disease up to 25%, which was the most reduction rate of disease symptoms among the studied isolates. S. carpaticus UTS49 demonstrated a strong and stable impact on colonization of cucumber and tomato rhizosphere. According to the biochemical and 16S rDNA, S. carpaticus UTS49 was identified and introduced as the best one against to the pathogen.