Molecular detection of Streptomyces griseus isolated from Isfahan soil

The aim of the present study was to detect Streptomyces griseus from Isfahan soil using biochemical, morphological and molecular techniques. Soil samples were collected from different regions (compost, 50 year old garden, river bed, clove, wheat farms and domestic yards) of Isfahan in two different seasons. One gram of each sample was serially diluted and cultivated in a primary isolation medium. Morphological shapes of colonies and vegetative hyphae were initially used to separate the grown bacteria of the samples. Various biochemical tests based on Bergey's manual of systemic bacteriology were performed to separate the Streptomyces from other related Genera. In order to further separate Streptomyces grisesus, Polymerase Chain Reaction (PCR) was used to detect the presence of aphE and strA genes in isolated colonies. Biochemical and morphological results, showed the presence of several species of Streptomyces in the collected samples. The expected band of 924 bp belonging to strA gene was observed in the positive control bacterial DNA (PTCC 1125). Several other bands were also observed in the positive control sample. From the total of 10 colonies that undergone molecular detection for the presents of strA gene, 6 colonies (W1, W3, W5, F4, F5, F26) showed only one band at 750 bp and four (W1, W3, F5, F26) showed an extra band of approximately 924 bp band as well. The expected band of 671 bp belonging to aphE gene was detected in positive control bacterial DNA (PTCC 1125). None of the soil samples, however, showed the presence of the aphE gene (data not shown).