Isolation, Evaluation and Molecular Identification of Streptomyces Isolates with Antimicrobial Activities

Abstract

Out of sixteen Streptomyces sp. isolates were isolated from root rhizosphere soil of tomato plants. Four isolates coded; C1, 8SW, 30SW and 11SA were selected as the highest antibiotic productivity. The highest records of the antibiotic productivity were 21 and 25 mm as inhibition zones obtained from the original strains 8SW and 11SA after 10 days using E. coli DH-5α as a tester. The highest records of the antibiotic productivity were 12 mm and 11 mm when used Aspergillus niger and Saccharomyces cerevisiae as testers. Three of the four tested Streptomyces isolates i.e. C1, 8SW and 11SA exhibited highly inhibited (31 mm) of the two fungal plant pathogens. Using RAPD and SRAP marker the clustering of tested isolates were different from each other, RAPD marker could be grouped isolates (C1 and 8SW), (30SW and 11SA) to two clusters. However, SRAP grouped isolates (C1, 8SW and 30SW) in one cluster, however isolate 11SA clustered separately. Based on DNA sequences using 16S rDNA the data showed that isolates C1 and 8SW belonged to Streptomyces albidoflavus andisolates 30SW and 11SA were belonged to Streptomyces bobbili. For more accuracy the isolate C1 aligned with all Streptomyces in gene bank and confirmed in belonged to S. albidoflavus.