Streptomyces sp. JCK-7385 Effectively Controls Fusarium Head Blight in Rice and Wheat

Fusarium head blight (FHB) primarily caused by Fusarium species including F. graminearum and F. asiaticum, is a major fungal disease affecting wheat, rice, and other cereal crops worldwide. Chemical fungicides remain the primary means of FHB management owing to their convenience and efficacy. Nonetheless, the overuse of chemical pesticides has led to fungicide resistance, human health effects, and environmental contamination, driving a shift toward biocontrol agents as sustainable alternatives for managing plant pathogens. This study aims to evaluate Streptomyces sp. JCK-7385, a rice-associated isolate, is an environmentally friendly biocontrol agent against FHB. The strain produced indole-3-acetic acid, siderophore, and 1-aminocyclopropane-1-carboxylic acid deaminase, as well as extracellular enzymes including cellulase, gelatinase, and chitinase. JCK-7385 treatments induced defense-related marker gene PR1 expression in transgenic Arabidopsis, as confirmed via β-glucuronidase assays, suggesting an induced resistance mechanism. In greenhouse trials, the JCK-7385 cell suspension and its suspension concentrate formulation (JCK-7385 SC) at a 2,000-fold concentration effectively reduced FHB incidence in rice by 42.3% and 52.5%, respectively. JCK-7385 SC also maintained high efficacy (54.4% control value) after storage at 45°C for 6 weeks. Furthermore, the integrated treatment of JCK-7385 SC and the chemical fungicide (Peulrei) significantly enhanced FHB control compared to single treatments, achieving 63.3% and 71.7% efficacy in rice and wheat, respectively. Field trials demonstrated that this collaborative treatment effectively suppressed FHB development in rice by 52.0%, outperforming individual applications. These findings suggest that Streptomyces sp. JCK-7385 has strong potential as a biological fungicide for FHB management through an induced resistance mechanism.