Paraburkholderia azotifigens sp. nov., a nitrogen-fixing bacterium isolated from paddy soil.

A Gram-stain-negative, aerobic, non-motile and rod-shaped bacterial strain, designated NF2-5-3T, was isolated from a paddy soil in Anseong city, Republic of Korea. This bacterium was characterized to determine its taxonomic position using a polyphasic approach. On the basis of 16S rRNA gene sequence analysis, strain NF2-5-3T had a close relationship with, and was related most closely to, members of the genus Paraburkholderia, namely Paraburkholderia caribensis MWAP64T (98.8 % similarity), P. sabiae Br3407T (98.8 %), P. hospita LMG 20598T (98.5 %), P. terrae NBRC 100964T (98.3 %) and P. phymatum STM815T (98.1 %). Growth of strain NF2-5-3T occurred at 15-37 °C, at pH 6.0-8.0 and at NaCl concentrations of 0-2 % (w/v). The major respiratory quinone was ubiquinone 8 (Q-8) and the major fatty acids were C16 : 0, summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c), C17 : 0 cyclo and C16 : 0 3-OH. The polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, unidentified aminophospholipids, unidentified aminolipids and unidentified polar lipids. The G+C content of the genomic DNA was 64.2 mol%. DNA-DNA relatedness values between strain NF2-5-3T and its closest phylogenetic neighbours were much lower than 70 %. Strain NF2-5-3T could be differentiated phylogenetically and phenotypically from recognized species of the genus Paraburkholderia. The isolate therefore represents a novel species, for which the name Paraburkholderia azotifigens sp. nov. is proposed, with NF2-5-3T (=KACC 18968T=LMG 29961T) as the type strain.