Actinomycetes Strain Selection From Maize Rhizosphere With Antagonistic Potential Against Fungal Phytopathogen

Fungal infestation in maize reduces productivity by 80%, with leaf blight disease causing about 60% reduction in grain yield. Numerous studies have shown the efficacy of synthetic chemicals in reducing the disease severity in agro-systems, which was efficient but with several negative impacts. Hence, there is an urgency to search for a more sustainable alternative with similar or better efficiency. This study was conceptualized to select a strain with in vitro antagonistic activity against leaf blight causative fungi and predict the secondary metabolites produced through the culture-dependent method and whole genome sequencing approach. Maize pathogens, Bipolaris sp., Fusarium equiseti , and Phoma sp., were obtained from symptomatic leaves and known to cause leaf blight diseases in maize crops, and antagonized by Streptomyces sp. OP7. The OP7 strain was isolated from the rhizosphere of maize crop and its cell-free supernatant extract showed antifungal activity against phytopathogens tested. The complete whole genome data of Streptomyces sp. OP7 revealed the presence of 16 biosynthetic gene clusters similar to metabolites with antifungal functional annotations implicating Strep tomyces sp. OP7’s capacity to produce valuable agroactive compounds.