Main content area

Rhizobium populi sp. nov., an endophytic bacterium isolated from Populus euphratica

Rozahon, Manziram, Ismayil, Nurimangul, Hamood, Buayshem, Erkin, Raziya, Abdurahman, Mehfuzem, Mamtimin, Hormathan, Abdukerim, Muhtar, Lal, Rup, Rahman, Erkin
International journal of systematic and evolutionary microbiology 2014 v.64 no.Pt 9 pp. 3215-3221
DNA, Populus euphratica, Rhizobium, bacteria, chemotaxonomy, endophytes, fatty acids, genes, nucleotide sequences, pH, phosphatidylcholines, phosphatidylethanolamines, phylogeny, ribosomal RNA, rivers, sequence homology, sodium chloride, stems, temperature, trees, China
An endophytic bacterium, designated K-38T, was isolated from the storage liquid in the stems of Populus euphratica trees at the ancient Ugan River in Xinjiang, PR China. Strain K-38T was found to be rod-shaped, Gram-stain-negative, aerobic, non-motile and non-spore-forming. Strain K-38T grew at temperatures of 25–37 °C (optimum, 28 °C), at pH 6.0–9.0 (optimum, pH 7.5) and in the presence of 0–3 % (w/v) NaCl with 1 % as the optimum concentration for growth. According to phylogenetic analysis based on 16S rRNA gene sequences, strain K-38T was assigned to the genus Rhizobium with highest 16S rRNA gene sequence similarity of 97.2 % to Rhizobium rosettiformans W3T, followed by Rhizobium nepotum 39/7T (96.5 %) and Rhizobium borbori DN316T (96.2 %). Phylogenetic analysis of strain K-38T based on the protein coding genes recA, atpD and nifH confirmed (similarities were less than 90 %) it to be a representative of a distinctly delineated species of the genus Rhizobium. The DNA G+C content was determined to be 63.5 mol%. DNA–DNA relatedness between K-38T and R. rosettiformans W3T was 48.4 %, indicating genetic separation of strain K-38T from the latter strain. The major components of the cellular fatty acids in strain K-38T were revealed to be summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c; 57.2 %), C16 : 0 (13.6 %) and summed feature 2 (comprising C12 : 0 aldehyde, C14 : 0 3-OH/iso-C16 : 1 I and/or unknown ECL 10.928; 11.0 %). Polar lipids of strain K-38T include phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, two unidentified aminophospholipids and two unidentified phospholipids. Q-10 was the major quinone in strain K-38T. Based on phenotypic, chemotaxonomic and phylogenetic properties, strain K-38T represents a novel species of the genus Rhizobium, for which the name Rhizobium populi sp. nov. is proposed. The type strain is K-38T ( = CCTCC AB 2013068T = NRRL B-59990T = JCM 19159T).