_____________________________________________________________________________________________________ *Corresponding author: Email: awadelkarim6@gmail.com; Asian Journal of Research in Biosciences 3(3): 1-9, 2021; Article no.AJORIB.454 Isolation and Identification of Azospirillium zeae from Acacia tortilis at Riyadh, Saudi Arabia Kamal H. Suliman 1,2 , F. N. Barakah 2 , Abdulaziz M. Assaeed 3 and Awad Elkarim Suliman Osman Khalifa 4* 1 Department of Soil and Water Sciences, Natural Resources and Environmental Studies University of Kordofan, Elobeid, Sudan. 2 Department of Soil Sciences, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia. 3 Department of Plant Production, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia. 4 Department of Desertification Studies and Environment, Institute of Gum Arabic Research and Desertification Studies, University of Kordofan, Elobied, Sudan. Authors’ contributions This work was carried out in collaboration among all authors. Author KHS designed the study, wrote the protocol and wrote the first draft of the manuscript. Author FNB performed the laboratory work and data collection. Author AMA performed the statistical analysis. Author AESOK managed the literature searches and amended the comments raised by the reviewers. Hereby, we read and approved the final manuscript. Received 10 April 2021 Accepted 15 June 2021 Published 19 June 2021 ABSTRACT The Study was conducted at Riyadh, Saudi Arabia to Isolate and Identify the Azospirillium zeae from Acacia tortilis. Useful bacteria associated with the plant roots have the potential to alleviate the burden of using costly and harmful agrochemicals in harsh environments. Finding of novel and appropriate bacteria for enhancing plant growth is among the main primary challenges involved in achieving the agronomic application of plant beneficial bacteria. A bacterium isolated from the rhizospheric soil of the legume Acacia tortilis was described based on several biochemical, morphological and molecular analyses. The bacterium H1P is motile, negative in biotin medium, no growth in 3% NaCl, negative D-Ribose, positive D- glucose. Identification of the isolate via 16s rDNA via the BLASTn revealed that the isolate is an Azospirillum species with a 96.9% similarity to Azospirillum zeae H1P. Phylogenetic analyses with MEGA6 software showed that the isolate shares an ancestor with Azospirillum zeae, eventually branching off into a separate taxon. Azospirillum zeae isolated from Acacia tortilis it is considered first report. Keywords: Acacia tortilis; rhizosphere; Saudi Arabia; Azospirillum; BLASTn. Original Research Article