Isolation and Characterization of Iranian Indigenous Azospirilla

In order to isolate and characterize the Iranian indigenous Azospirilla, 404 soil and plant samples were collected from 12 provinces. One hundred and fifty isolates capable of forming a veil-like pellicle in a semi solid medium, free of N and with bromethymole blue (NFB), were subjected to primary isolation and characterization. Seventy six isolates were tested and classified into 4 species, based on their growth in a 3% medium of sodium chloride, biotin requirements, consumption and production of acid from glucose and production of polymorphous cells in a NFB medium. The phenotypic specification of indigenous species were compared with those of A.lipoferum, A.brasilense, A.irakense and A.halopraeferense. The highest number of isolated species belonged to Golestan (25 isolate), Fars, and Khozestan Provinces, respectively. Despite the higher area and number of sampling at Khorasan province, the lowest number of isolates belonged to this province. This may be attributed to the low level of organic matter and unfavorable agricultural condition at this province. Most of the isolated species (80%) were collected from rhizosphere of the gramineous plants, especially wheat. Among the identified species, A.lipoferum was the highest in number, followed by A.brasilense and A.irakense. Only one isolate was morphologically and physiologically similar to A.halopraeferense.