title: Mesorhizobium thiogangeticum sp. nov., a novel sulfur-oxidizing chemolithoautotroph from rhizosphere soil of an Indian tropical leguminous plant.
abstract: The bacterial strain SJT(T), along with 15 other mesophilic, neutrophilic and facultatively sulfur-oxidizing chemolithotrophic isolates, was isolated by enrichment on reduced sulfur compounds as the sole energy and electron source from soils immediately adjacent to the roots of Clitoria ternatea, a slender leguminous herb of the Lower Gangetic plains of India. Strain SJT(T) was able to oxidize thiosulfate and elemental sulfur for chemolithoautotrophic growth. 16S rRNA and recA gene sequence-based phylogenetic analyses showed that the Gram-negative rod-shaped bacterium belonged to the genus Mesorhizobium and was most closely related to Mesorhizobium loti, Mesorhizobium plurifarium, Mesorhizobium amorphae and Mesorhizobium chacoense. Unequivocally low 16S rRNA (<97 %) and recA (< or =88 %) gene sequence similarities to all existing species of the most closely related genera, a unique fatty acid profile, a distinct G+C content (59.6 mol%) and phenotypic characteristics all suggested that strain SJT(T) represents a novel species. DNA-DNA hybridization and SDS-PAGE analysis of whole-cell proteins also confirmed the taxonomic uniqueness of SJT(T). It is therefore proposed that isolate SJT(T) (= LMG 22697T = MTCC 7001T) be classified as the type strain of a novel species, Mesorhizobium thiogangeticum sp. nov.
authors.affiliation: Department of Microbiology, Bose Institute, P-1/12, CIT Scheme VII-M, Kolkata - 700 054, India. Wriman@rediffmail.com
authors.forename: Wriddhiman
authors.initials: W
authors.lastname: Ghosh
authors.forename: Pradosh
authors.initials: P
authors.lastname: Roy
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D001482:Base Composition; D031292:Clitoria / Q000382:microbiology*; D005227:Fatty Acids; D007194:India; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D018517:Plant Roots / Q000382:microbiology; D020560:Proteobacteria / Q000737:chemistry / Q000145:classification* / Q000302:isolation & purification / Q000502:physiology; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D011938:Rec A Recombinases / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D012988:Soil Microbiology; D013045:Species Specificity; D013455:Sulfur / Q000378:metabolism; D013885:Thiosulfates / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D005227:Fatty Acids; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D013885:Thiosulfates; D013455:Sulfur; D011938:Rec A Recombinases