Genomic and functional characterization of rice rhizosphere-associated Streptomyces for sheath blight suppression with potential for scalable agricultural application

Plant growth–promoting bacteria (PGPB) are increasingly explored as sustainable alternatives to agrochemicals for improving crop productivity and disease resilience. However, the successful application of effective strains requires linking genomic potential with functional performance and production feasibility. Here, we characterized two rice rhizosphere–associated Streptomyces isolates, FT1 and FB2, for their plant growth–promoting and biocontrol potential against the sheath blight pathogen Rhizoctonia solani AG-1 IA. Genome analyses revealed genes associated with plant-beneficial traits, antimicrobial activity, and diverse biosynthetic gene clusters, indicating strong potential for rhizosphere adaptation and pathogen suppression. Functional validation showed that both isolates inhibited R. solani growth in vitro, reduced sheath blight severity in detached leaf assays, and improved rice seed germination and early seedling growth under pathogen pressure. In addition to disease suppression, both strains exhibited multiple plant growth–promoting traits consistent with genomic predictions. Further, phenotypic profiling was conducted to guide cultivation strategies and medium selection for techno-economic evaluation. The assessment identified sucrose as a cost-effective carbon source for fermentation, supporting the feasibility of scalable production. Overall, this study demonstrates the value of integrating comparative genomics, phenotypic validation, and techno-economic analysis to accelerate the development of PGPB-based solutions. Our findings highlight Streptomyces sp. FT1 and FB2 as promising candidates for sustainable rice health management and provide a practical framework for translating beneficial microbes into economically viable agricultural applications.