Biocontrol of wilt disease of rice seedlings incited by Fusarium oxysporum through soil application of Streptomyces chilikensis RC1830.

The genus Streptomyces includes many antifungal metabolite-producing novel strains. Fusarium oxysporum soil-inhabiting pathogenic fungi, that affects rice to cause wilt disease. This work demonstrates the efficacy of novel Streptomyces chilikensis strain RC1830, previously isolated from estuarine habitat Chilika Lake in preventing the F. oxysporum wilting/root rot disease and promoting the growth of rice (Var. Swarna) seedlings. A total of 25 different compounds were identified from crude extracts of S. chilikensis RC1830 by GC-MS. In pot trial experiments, Streptomyces-treated rice seedlings showed significantly reduced disease severity index by 80·51%. The seedlings growth parameters (root length, root fresh weight and root dry weight) were also increased by 53·91, 62·5 and 73·46%, respectively, in Streptomyces-treated groups of seedlings compared to Fusarium-infected seedlings. Similarly, the shoot length, shoot dry weight and shoot fresh weight were also increased by 26, 58 and 34·4%, respectively, in Streptomyces-treated groups of seedlings compared to Fusarium-infected seedlings. Formulations of the strain were prepared using seven organic and inorganic wastes as the carrier material and the shelf lives of the propagules were also monitored. Vermiculite and activated charcoal formulations stored at 4°C exhibited a higher viable cell count after 3 months of storage.