Unveiling the biocontrol potential of Streptomyces sp. OR02 against Rhizoctonia solani in Tomato fruit

Rhizoctonia solani is a major microbial pathogen that affects harvested tomatoes during shipping and storing. Synthetic fungicides are extensively applied to control postharvest decay loss, but due to their deleterious effects and evolved resistance to pathogens, the current trend is moving toward more safer and eco-friendly alternatives. The increasing popularity of utilizing antagonistic biocontrol microbes, such as Streptomyces, has effectively addressed postharvest diseases in fruit. In this study, Streptomyces sp. OR02 with high antifungal activity against Rhizoctonia solani was isolated from Orang National Park, Assam. Morphological and 16S rRNA gene sequence analysis identified the strain as Streptomyces sp. (PP338111). Streptomyces sp. OR02 ethyl acetate extract was used to control the disease caused by Rhizoctonia solani on tomato by fruit acupuncture method. The treatment significantly reduced the disease severity and incidence in the infected tomatoes. The MIC and MFC values were found to be 10 mg L−1 and 20 mg L−1, respectively. The extract of OR02 significantly inhibited both mycelial growth as well as spore germination of Rhizoctonia solani. Also, strain OR02 demonstrated a broad-spectrum antifungal activity against different phytopathogenic fungi. Further, GC-MS analysis identified important volatile organic compounds. These results exemplify the use of the strain Streptomyces sp. OR02 as a promising biocontrol agent to reduce the postharvest disease of tomatoes caused by Rhizoctonia solani. •Streptomyces sp. OR02 extract combats R. solani in tomato fruit.•OR02 extract inhibits R. solani growth, reducing tomato disease severity.•Metabolic analysis of OR02 extract identifies potent antimicrobial compounds.