Azospirillum oryzae sp. nov., a nitrogen-fixing bacterium isolated from the roots of the rice plant Oryza sativa

The taxonomic position of the free-living diazotrophic strain COC8^T isolated from rice was investigated based on phylogenetic analyses. 16S rRNA gene sequence analyses indicated that strain COC8^T was closely related to the genus Azospirillum (96 % similarity). Chemotaxonomic characteristics (G+C content of the DNA 66·8 mol%, Q-10 quinone system, 18 : 1ω7c as the major fatty acid and 14 : 0 3-OH and 16 : 0 3-OH as the major hydroxy fatty acids) were also similar to those of the genus Azospirillum. Based on its physiological characteristics, strain COC8^T can clearly be differentiated from recognized species of Azospirillum. The name Azospirillum oryzae sp. nov. is proposed to accommodate this bacterial strain; the type strain is COC8^T (=IAM 15130^T=CCTCC AB204051^T).