Xanthomonas translucens is the causal agents of bacterial leaf streak in wheat plants worldwide. Many bacteria in plant rhizosphere have ability to inhibit growth of pathogens. In this study, 2 isolates, Ph20 and Rh17 which isolated from wheat rhizosphere in Khorasan Razavi, showed growth inhibition halo against X. transluscens with 33.66±0.61mm and 24.66±0.25mm respectively. The isolates were tested for their ability to control bacterial leaf streak in greenhouse conditions. The length of streak on the leaves in the treated samples were significantly smaller than the negative control. Isolates Ph20, Rh17, reduced symptoms more than others with disease inhibition index of 82.57±4.55%, 59.7±2.98%, respectively. Among the 2 selected isolates, only isolate Ph20 produced cellulase, protease, ACC deaminase and fixed nitrogen. The Ph20 isolate could solubilize 89.72μg/ml phosphate in medium. This isolate also produced 12.56±0.3 μg/ml IAA. Root and shoot length, dry and wet weight were significantly increased in plants treated with Ph20. Seed germination in seeds treated with isolate Ph20 increased by 18.75%. The Ph20 isolate was identified as Stenotrophomonas maltophilia according to 16S rRNA gene sequencing.

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