In the present study, Streptomycetes species was isolated from rhizosphere soil samples of the Alternenthera sessilis Linn. which were collected from agricultural fields at Gudugeri, Dharwad, Karnataka. Streptomycetes sp. is a gram-positive, aerobic, non-motile, spore-forming filamentous bacterium and it was designated as Streptomycetes strain RSA-14, it was found to possess an extensive spectrum of antimicrobial activity against pathogenic microorganisms. The isolate was tested for their potential to grow in presence of antibiotics including penicillin, streptomycin, chloramphenicol, gentamycin, and tetracycline on Muller Hinton agar media containing those antibiotics one by one at the finest temperature for few days. The strain RSA-14 became sensitive to chloramphenicol, penicillin and tetracycline, proof against streptomycin and intermediate to gentamycin. Further, the most potent stress RSA-14 became characterized via physiological, biochemical and 16S rRNA gene sequencing. The 16S rRNA gene sequencing and evaluation of the phylogenetic tree showed a 100% series similarity with Streptomycetes cinereoruber strain P.B.373.
Key words: Streptomycetes sp, Rhizosphere soil, Antimicrobial activity, Antibiotic sensitivity, 16S rRNA gene sequencing.
|
