Azospirillum griseum sp. nov., isolated from lakewater

A novel Gram-stain-negative, strictly aerobic, rod-shaped, gray-pigmented bacterial strain, designated L-25-5 w-1^T, was isolated from the water at Baiyang Lake, PR China. Cells of strain L-25-5 w-1^T were motile, with a single polar flagellum. L-25-5 w-1^T was able to grow at 15-37 °C (optimum 37 °C) and pH 5-8 (optimum pH 6) in R2A medium. 16S rRNA gene sequence analysis and phylogenetic analysis of L-25-5 w-1^T showed the highest relationship to Azospirillum doebereinerae GSF71^T (97.9 %), Azospirillum thiophilum DSM 21654^T (97.9 %) and Azospirillum agricola CC-HIH038^T (97.0 %), with other species of the genus Azospirillum showing less than 97 % sequence similarity. The predominant polar lipids were phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol and two unidentified aminolipids; the major cellular fatty acids were C_16 : 0, C_16 : 0 3-OH, C_18 : 1 2-OH, iso-C_18 : 0, summed feature 2 (C_12 : 0 aldehyde and/or unknown 10.9525 and/or iso-C_16 : 1I and/or C_14 : 0 3-OH), summed feature 3 (C_16 : 1ω7c and/or C_16 : 1ω6c) and summed feature 8 (C_18 : 1ω7c and/or C_18 : 1ω6c); and the major respiratory quinone was ubiquinone 10. The draft genome size of L-25-5 w-1^T was 5.8 Mbp, and the DNA G+C content was 66.6 %. The average nucleotide identity value and digital DNA-DNA hybridization relatedness value between L-25-5 w-1^T and related type strains were 80.2 and 24.7 % with A. doebereinerae GSF71^T and 78.8 and 23.6 % with A. thiophilum DSM 21654^T, respectively. According to the phylogenetic, chemotaxonomic and genotypic properties, strain L-25-5 w-1^T represents a novel species in the genus Azospirillum, for which the name Azospirillum griseum sp. nov. is proposed. The type strain is L-25-5 w-1^T (=CGMCC 1.13672^T=KCTC 62777^T).