Identification of a Novel Streptomyces Species for Management of Plant Disease

Native isolates of groundnut stem rot casual organism, Sclerotium rolfsii Sacc. Were collected from major groundnut growing areas of Tamil Nadu. Selected isolates were screened, characterized and indentified the virulent isolate (GNSR1). Several native bacterial and fungal antagonists were isolated against GNSR1. Two antagonistic isolates, viz., GNRAJK1 and GNRAVR14, were found to have antagonistic effects on GNSR1. Morphology and spore structure of isolated antagonists, GNRAJK1 and GNRAVR14, were studied under Light microscopy, Biochemical test, Thin layer chromatography and Biolog analysis. It confirmed the group of micro organisms as Streptomyces based on gram staining, medium specific growth, visual morphological characters, cell wall amino acid studies and spore forming chraracters. The genus and species level of the antagonists were identified by Fatty Acids Methyl Esters (FAME) Analysis. The isolate GNRAJK1 had a SIM index of 0.007 and was identified as Streptomyces violaceusniger, and GNRAVR14 had a SIM index of 0.013 and was identified as Streptomyces exfoliatus.