Soil samples and initial screening for antagonistic bacteria. A total number of 148 soil samples were obtained from different parts of the province of Tehran, Iran. All the samples were transferred to the laboratory in sterile plastic containers. For initial screening of inhibitory soils, 0.1 g of each soil sample was suspended in 0.5 ml 0.9% (w/v) NaCl, mixed by vortex for 30 s, and centrifuged at 2500 rpm for 30 s. Two µl of A. niger conidial suspension (2×105 conidia/ml) was spotted onto the center of a GY (Glucose 2.0%, Yeast extract 0.5%, Agar 1.5%) plate, and 10 µl supernatant of each soil sample was placed around the periphery of the plate, 3 cm distance from the A. niger spot. Screen plates were incubated at 28°C for 5 days and assessed visually for antifungal phenotypes (10).