Isolation, morphology characterization and an Antagonistic activity of Bacillus subtilis against Sheath Blight of Rice {Oryza sativa L.} caused by Rhizoctonia solani Kuhn.
R. Kannan and K. Sanjeevkumar
Department of Plant Pathology, Faculty of Agriculture, Annamalai University, Annamalai Nagar- 608 002 {India} email: pathosanjeev@yahoo.co.in
ABSTRACT
Bacillus subtilis is one of the major plant growth promoting rhizobacteria (PGPR) and act as predominant bio control agents against many plant pathogens of crop plants. The present study was made to isolated the different Bacillus strains and selected to assess their capability to inhibition of rice sheath blight pathogen. Among the different isolates Bacillus sp. tested, based on the topography, shape, colour and colony characters of Bacillus sp. the isolates collected were grouped into five categories. All isolates were proved to be Gram positive. Positive results were obtained for Starch hydrolysis, Gelatin liquefaction Casein Hydrolysis, IAA production, HCN Production and Catalase test. Similarly, negative reaction was obtained for pigement test, Methyl red test, H2S test and Urease utilization confirming the isolates to be Bacillus spp. The isolate B. subtilis (AUBS 2) was found to be the most effective against R. solani in dual culture. In poisoned food technique, the mycelial growth and sclerotial germination of R. solani was found to be reduced with an increase in the conc. of culture filtrate of B. subtilis. The culture filtrate of B. subtilis at 20 per cent conc. completely inhibited the mycelial growth and sclerotial germination of R. solani.