Rhizobium flavescens sp. nov., Isolated from a Chlorothalonil-Contaminated Soil

• Published in: Current microbiology Vol. 78; no. 5; pp. 2165 - 2172
• Main Authors: Su, Xiao-Jing, Liu, Gui-Ping, Zhang, Long, Zhou, Xi-Yi, Qiao, Wen-Jing, Jiang, Jian-Dong
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2021; Springer Nature B.V
• Subjects: Bacterial Typing Techniques; Biomedical and Life Sciences; Biotechnology; China; Chlorothalonil; Deoxyribonucleic acid; DNA; DNA, Bacterial - genetics; Fatty Acids; Gene sequencing; Genes; Genomes; Hybridization; Life Sciences; Microbiology; New species; NifH gene; Nitriles; Nucleic Acid Hybridization; Nucleotides; Phylogenetics; Phylogeny; Reductases; Rhizobiaceae; Rhizobium - genetics; RNA, Ribosomal, 16S - genetics; rRNA 16S; Sequence Analysis, DNA; Similarity; Soil; Soil contamination; Soil pollution; Soils; China
• ISSN: 0343-8651; 1432-0991
• DOI: 10.1007/s00284-021-02462-4

A Gram-negative, facultative anaerobic, non-lagellated and rod-shaped bacterium FML-4 T was isolated from a chlorothalonil-contaminated soil in Nanjing, China. Phylogenetic analyses of 16S rRNA genes revealed that the strain FML-4 T shared the highest sequence similarity of 97.1% with Ciceribacter thiooxidans KCTC 52231 T , followed by Rhizobium rosettiformans CCM 7583 T (97.0%) and R. daejeonense KCTC 12121 T (96.8%). Although the sequence similarities of the housekeeping genes thrC , rceA , glnII , and atpD between strain FML-4 T and C. thiooxidans KCTC 52231 T were 83.8%, 88.7%, 86.2%, and 92.0%, respectively, strain FML-4 T formed a monophyletic clade in the cluster of Rhizobium species. Importantly, the feature gene of the genus Rhizobium , nifH gene (encoding the dinitrogenase reductase), was detected in strain FML-4 T but not in C. thiooxidans KCTC 52231 T . In addition, strain FML-4 T contained the summed feature 8 (C 18:1 ω 7 c and/or C 18:1 ω 6 c ), C 19:0 cyclo ω 8 c and C 16:0 as the major fatty acids. Genome sequencing of strain FML-4 T revealed a genome size of 7.3 Mbp and a G+C content of 63.0 mol%. Based on the results obtained by phylogenetic and chemotaxonomic analyses, phenotypic characterization, average nucleotide identity (ANI, similarity 77.3–75.4%), and digital DNA–DNA hybridization (dDDH, similarity 24.5–22.3%), it was concluded that strain FML-4 T represented a novel species of the genus Rhizobium , for which the name Rhizobium flavescens sp. nov. was proposed (type strain FML-4 T  = CCTCC AB 2019354 T  = KCTC 62839 T ).