Pseudomonas lopnurensis sp. nov., an endophytic bacterium isolated from Populus euphratica at the ancient Ugan river

Abstract

A Gram-stain negative, aerobic, rod-shaped, motile by a single polar flagellum, non-spore-forming bacterium, designated strain AL-54^T, was isolated from the storage liquid in the stems of Populus euphratica tree at the ancient Ugan River in Xinjiang, PR China. Isolated AL-54^T grew optimally at pH 7.0 and temperature 35 °C in the presence of 3% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence demonstrated that the isolate belonged to the genus Pseudomonas and was closely related to Pseudomonas songnenensis NEAU-ST5-5 ^T (97.6%), Pseudomonas zhaodongensis NEAU-ST5-21 ^T (97.5%), Pseudomonas alcaliphila AL15-21^T (97.3%), Pseudomonas toyotomiensis HT-3^T (97.3%), Pseudomonas oleovorans subsp. lubricantis RS1^T (97.3%), Pseudomonas stutzeri ATCC 17588^T (97.3%), Pseudomonas chengduensis CGMCC 2318^T (97.2%), and Pseudomonas xanthomarina KMM 1447^T (97.1%). Multilocus Sequences Analysis (MLSA) of strain AL-54^T based on the three housekeeping genes, rpoB, rpoD and gyrB further confirmed the phylogenetic assignment of the isolates. The G+C content was 64.7 mol%. The DNA-DNA hybridization with P. songnenensis NEAU-ST5-5 ^T, P. zhaodongensis NEAU-ST5-21^T, P. alcaliphila AL15-21^T, P. toyotomiensis HT-3^T, P. oleovorans subsp. lubricantis RS1^T, P. stutzeri ATCC 17588^T, P. chengduensis CGMCC 2318^T and P. xanthomarina KMM 1447^T revealed 44.0%, 44.7%, 60.1%, 48.7%, 49.1%, 60.1%, 58.9% and 60.2% relatedness respectively. The predominant quinone system is ubiquinone-9 (Q-9). The major components of the cellular fatty acids (>10%) were summed feature 8 (comprising C_18:1 ω7c /C_18:1 ω6c), summed feature 3 (comprising C_16:1 ω7c /C_16:1 ω6c) and C_16:0. The detected major polar lipids were phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG) and phosphatidylcholine (PC). On the basis of phenotypic data, chemotaxonomic and phylogenetic properties, strain AL-54^T can consider as a novel species within the genus Pseudomonas, for which the name Pseudomonas lopnurensis sp. nov. is proposed. The type strain is AL-54^T (= JCM 19136^T = CCTCC AB 2013066^T = NRRL B-59987^T).

Keywords: Phylogenetic analysis; Populus euphratica trees; Pseudomonas lopnurensis sp. nov..