SANNAZZARO Analia Ines
Mesorhizobium intechi sp. nov. isolated from nodules of Lotus tenuis in soils of the Flooding Pampa, Argentina
ESTRELLA, MARIA JULIA; FONTANA, MA. FLORENCIA; CUMPA VELÁZQUEZ, LIZ; TORRES TEJERIZO, GONZALO; DIAMBRA, LUIS; HANSEN, LARS; PISTORIO, MARIANO; SANNAZZARO, ANALÍA INÉS
SYSTEMATIC AND APPLIED MICROBIOLOGY
Three symbiotic nitrogen-fixing bacteria (BD68T, BD66 and BD73) isolated from root nodules of Lotus tenuis in lowlands soils of the Flooding Pampa (Argentina), previously classified as members of the Mesorhizobium genus, were characterized. Phylogenetic analysis of their 16S rRNA gene sequences showed a close relationship to M. japonicum MAFF 303099T, M. erdmanii USDA 3471T, M. opportunistum WSM 2975T, M. jarvisii ATCC 33669T and M. huakuii LMG 14107T, with sequence identities of 99.78% - 100%. Multilocus sequence analysis of other housekeeping genes revealed that the three isolates belong to a phylogenetically distinct clade within the genus Mesorhizobium. The strain BD68T was designated as a group representative and its genome was fully sequenced. The Average Nucleotide Identity and in silico DNA-DNA hybridization comparisons between BD68T and the most related type strains showed values that are below the accepted threshold for species discrimination. Phenotypic and chemotaxonomic features were also studied.On the basis of our results, BD68T, BD66 and BD73 can be considered to represent a novel species of the genus Mesorhizobium, for which the name Mesorhizobium intechi sp. nov. is hereby proposed. The type strain of this species is BD68T (= CECT 9304T = LMG 30179T).