Streptomyces hygroscopicus subsp. hygroscopicus 5-4: A Potential Biocontrol Agent for Fusarium Wilt of Banana

This text discusses the potential use of endophytic actinomycetes, specifically 'Streptomyces hygroscopicus subsp. hygroscopicus 5-4', as a biocontrol agent for Fusarium wilt of banana caused by 'Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4)'. The study isolated 144 actinomycetes from different tissues of medicinal plants, with 43 exhibiting antifungal activities against Foc TR4. Strain 5-4, isolated from roots of 'Piper austrosinense', was found to have a broad-spectrum antifungal activity due to the production of chitinase and β-1,3-glucanase. Application of strain 5-4 significantly reduced the disease index of banana wilt and increased the expression levels of defense genes. The antifungal mechanism assay demonstrated that extracts of strain 5-4 inhibited spore germination and hyphal growth of Foc TR4, making it a potential biological agent for controlling Fusarium wilt of banana.