Isolation of Antagonistic Actinomycetes SPS from Rhizosphere of BT Cotton

The plant microbe interaction in the rhizosphere is one of the major factors regulating the health and growth of plants. Actinomycetes are common filamentous soil microorganisms important in maintaining a satisfactory biological balance in the soil, largely because of the ability to produce antibiotics. In the present study Antagonistic Actinomycetes species was isolated from rhizosphere of Bt cotton. Seven types of isolated Actinomycetes colonies were isolated from crowded plate method and were screened primarily by Giant colony technique. Three strains with best antifungal activity were further screened by Well Diffusion method and the best member which has good antifungal activity was selected and named as BtAS. This strain was studied for it’s morphological, physiological characteristics according to Bergey’s Manual and further studied by molecular characterization and was identified as Streptomyces filamentosus. The 16s rRNA gene sequence (1472 bp) of isolate was deposited at NCBI GeneBank with Accession Number KF939135. The antagonistic nature of the isolated strain was determined for its anti-fungal activity by Well Diffusion method, MIC and Inhibition of phytopathogenic fungi likeA. alternata,F.moniliformae, M. phaseolina, R. solaniand A. niger in liquid medium. The results indicate that Streptomyces f lam ntosusisolatedfrom rhizosphere of Bt c tton has Good Antifungal activity and it was mor effective against F.moniliformae when compared with other test fungi.