Evaluation of the Effectiveness of Soil Streptomyces Isolates for Induction of Plant Resistance Against Tomato mosaic virus (ToMV).

The ability of various Streptomyces isolates obtained from soil to induce systemic resistance in tomato (Solanum lycopersicum cv. Supra) plant against Tomato mosaic virus (ToMV) was characterized in current study. Importantly, of nine Streptomyces isolates tested herein, the culture filtrate (CF) of one isolate, designated as Streptomyces ovatisporus LC597360, was the most effective. It exhibited 93.9% biocontrol efficacy and induced a significant decrease (17.6 ± 0.8%) of symptoms severity compared with infected control plants. These finding were confirmed using I-ELISA showing that ToMV concentration was significantly reduced in plants treated with S. ovatisporus LC597360 CF as compared with plants inoculated with ToMV. Moreover, treatment with CF of S. ovatisporus LC597360 not only increased activity of defense-related enzymes such as ascorbate oxidase, catalase, peroxidase, and polyphenol oxidase, but also induced plant growth promotion. The present study is the first one that demonstrates the potential of S. ovatisporus LC597360 in biocontrol of ToMV and investigated its antiviral mechanisms.