Main content area

Nitrospirillum irinus sp. nov., a diazotrophic bacterium isolated from the rhizosphere soil of Iris and emended description of the genus Nitrospirillum

Chung, Eu Jin, Park, Tae Soon, Kim, Kyung Hyun, Jeon, Che Ok, Lee, Hae-In, Chang, Woo-Suk, Aslam, Zubair, Chung, Young Ryun
Antonie van Leeuwenhoek 2015 v.108 no.3 pp. 721-729
Azospirillum, DNA, Iris ensata, Rhodocista, Skermanella, altitude, bacteria, chemotaxonomy, fatty acids, flagellum, glycolipids, nucleotide sequences, pH, phosphatidylcholines, phosphatidylethanolamines, phylogeny, rhizosphere, ribosomal RNA, sequence homology, soil, wetlands, Korean Peninsula
A polyphasic approach was used to characterize a novel nitrogen-fixing bacterial strain, designated YC6995ᵀ, isolated from the rhizosphere soil of Iris ensata var. spontanea (Makino) Nakai inhabiting a wetland located at an altitude of 960 m on Jiri Mountain, Korea. Strain YC6995ᵀ cells were Gram-negative, and rod-shaped, with motility provided by a single polar flagellum. Optimal growth conditions were 30 °C and pH 7.0. The major fatty acids of strain YC6995ᵀ were C₁₈:₁ ω7c, C₁₈:₁ 2-OH and C₁₆:₀ 3-OH. The major respiratory quinone was ubiquinone-10 (Q-10). The polar lipids were phosphatidylethanolamine, phosphatidyldimethylethanolamine, phosphatidylcholine, phosphatidylglycerol and unidentified glycolipids. The genomic DNA G+C content was 64.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed strain YC6995ᵀ to form a phyletic lineage with Nitrospirillum amazonense DSM 2787ᵀ with a high sequence similarity (97.2 %), but it displayed low sequence similarity with other remotely related genera, including Azospirillum (<93 %), Rhodocista (93.1–93.4 %), and Skermanella (91.2–93.3 %) in the family Alphaproteobacteria. Based on the phenotypic, chemotaxonomic, and phylogenetic evidences, strain YC6995ᵀ represents a novel species within the genus Nitrospirillum, for which the name Nitrospirillum irinus sp. nov. is proposed. The type strain is YC6995ᵀ (= KACC 13777ᵀ = DSM 22198ᵀ). An emended description of the genus Nitrospirillum is also proposed.