Abstract
This study was carried out with the isolation of Streptomyces bacteria from soil samples of Dilam city. Seventy two (72) Streptomyces isolates were isolated and purified using starch nitrate agar medium. On the other hand, nine (9) phytopathogenic fungi were isolated from rotted roots of six different plants, namely Triticum aestivum (wheat), Trifolium trifolium (clover), Coriandrum sativum (coriander), Cucurbita pepo (zucchini), Cucumis sativus (cucumber) and Avena sativa (oat). These fungi were primarily identified as Fusarium sp(w) (from diseased wheat), Fusarium sp(c) and Macrophamina sp(c) (from diseased clover), Fusarium sp(co), Macrophamina sp(co) and Rhizoctonia sp(co) (from diseased coriander), Fusarium sp(z) (from diseased zucchini), Fusarium sp(cu) (from diseased cucumber) and Fusarium sp(o) (from diseased oat). Screening test was done for all Streptomyces isolates against phytopathogenic fungi to determine the antifungal activity. The antifungal activity was shown at 24 Streptomyces isolates by various efficacies. However, Streptomyces isolate number 13 (S-13) has the highest antifungal activity especially against 6 fungi, Fusarium sp(w), Fusarium sp(c), Macrophamina sp(c), Macrophamina sp(co), Rhizoctonia sp(co) and Fusarium sp(cu). The isolate S-13 was identified as Streptomyces collinus albescens by using gene for 16S rRNA which was firstly recorded in gene bank with accession number AB184101.2. Optimum factors were studied to obtain the maximum yield of antifungal compound. The 5th day has the best incubation period, 30 degrees C is a best incubation temperature, 7.5 is a best pH value, with glucose and ammonium nitrate as the best carbon and nitrogen source, respectively.