Pseudomonas yamanorum sp. nov., a new psychrotolerant bacterium isolated from Sub-Antarctic environment (Tierra del Fuego, Ushuaia)

Abstract

A psychrotolerant strain, 8H1T was isolated from soil samples collected in Isla de los Estados , Ushuaia, Argentina. Cells were Gram negative, aerobic, straight rods, occurring singly or in pairs, non-spore-forming and motile by mean of two polar flagella. The isolate was able to grow in the 4-35 °C range, with an optimum rate at 28 °C. The predominant cellular fatty acids were summed feature 3 (C16:1 ω6c and/or C16:1 ω7c; 38.0 %), C16:0 (35.4 %) and summed feature 8 (C18:1 ω7c; 9.5 %). The polar lipid pattern of strain 8H1T comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and phospholipid. Ubiquinone 9 (Q-9) was the predominant lipoquinone. DNA G+C content was 59.8 mol%. 16S rRNA gene sequence-based phylogeny suggested the affiliation of isolate 8H1T to the Pseudomonas fluorescens group; displaying ≥98.5 % sequence similarities among 29 type strains. However, MLSA study by concatenating 16S rRNA, gyrB, rpoD and rpoB genes showed that isolate 8H1T could be discriminated from closely related Pseudomonas species and placed in the Pseudomonas gessardii subgroup, including the species with the highest MLSA sequence similarities: P. brenneriT (96.2 %), P. gessardiiT (96.1 %), P. proteolyticaT (96.0 %), P. meridianaT (96.0 %), P. mucidolensT (95.4 %). DNA-DNA hybridization analysis between 8H1T and these closely related type strains revealed relatedness values of 27.0, 8.8, 41.2, 39.7 and 46.1 %, respectively. These results together with differences in several phenotypic features support the classification of a novel species for which the name Pseudomonas yamanorum sp. nov. is proposed. The type strain is 8H1T (=DSM 26522T =CCUG 63249T= LMG 27247T).