In this study, samples from the roots, leaves and stems of healthy oak trees were collected from various locations of Baneh and Marivan regions, Iran. In total, 63 endophytic bacteria were isolated and grouped according to phenotypic properties. Seven selected isolates were further identified by partial sequencing of the 16S rRNA gene. According to the results, isolates Pp54, Pp88, Pp95 and Pp177 belonged to the Pseudomonas genus, isolates Sm59 and Sm79 belonged to the Stenotrophomonas genus and isolate Bf 172 was identified as a member of the Bacillus genus. Ability of these isolates was evaluated forto phytohormone production such as auxin and gibberellin, siderophore production, phosphate solubilization, atmospheric nitrogen fixation, protease and hydrogen cynide production. All strains were capable ofto producinge the plant growth hormones auxin and gibberellin in different amounts. Atmospheric nitrogen fixation ability was positive for strains Sm79, Pp54, Pp88 and Pp95. All strains except Sm79 were able to solubilize phosphate. The results of protease production by strains Sm59, SM79, Pp88, Pp177 and Bf172 were positive. Pp88, Pp95, Bf172 and Pp177 were able to produce siderophore. Strains Sm79 and Pp95 was able tocan produce low amounts of hydrogen cyanide. Amongst the strains tested, Pp95, Pp88, Pp177 and Sm79 had different inhibition effects on bacterial plant pathogen, Pseudomonas syringae pv. syringae under in vitro conditions. This is the first reported case about isolation of endophytic bacterial strains isolation belonging to Bacillus, Pseudomonas and Stenotrophomonas genus from of oak trees in Iran.
