Open AccessRhizobium dioscoreae sp. nov., a plant growth-promoting bacterium isolated from yam (Dioscorea species)
Author(s) -
Michel Ouyabe,
Naoto Tanaka,
Yuh Shiwa,
Nobuyuki Fujita,
Hidehiko Kikuno,
Pachakkil Babil,
Hironobu Shiwachi
Publication year - 2020
Publication title -
international journal of systematic and evolutionary microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 173
eISSN - 1466-5034
pISSN - 1466-5026
DOI - 10.1099/ijsem.0.004381
Subject(s) - biology , rhizobium , dioscorea , botany , 16s ribosomal rna , phylogenetic tree , bacteria , strain (injury) , gene , genetics , medicine , alternative medicine , pathology , anatomy
This study investigated endophytic nitrogen-fixing bacteria isolated from two species of yam (water yam, Dioscorea alata L.; lesser yam, Dioscorea esculenta L.) grown in nutrient-poor alkaline soil conditions on Miyako Island, Okinawa, Japan. Two bacterial strains of the genus Rhizobium , S-93 T and S-62, were isolated. The phylogenetic tree, based on the almost-complete 16S rRNA gene sequences (1476 bp for each strain), placed them in a distinct clade, with Rhizobium miluonense CCBAU 41251 T , Rhizobium hainanense I66 T , Rhizobium multihospitium HAMBI 2975 T , Rhizobium freirei PRF 81 T and Rhizobium tropici CIAT 899 T being their closest species. Their bacterial fatty acid profile, with major components of C 19 : 0 cyclo ω 8 c and summed feature 8, as well as other phenotypic characteristics and DNA G+C content (59.65 mol%) indicated that the novel strains belong to the genus Rhizobium . Pairwise average nucleotide identity analyses separated the novel strains from their most closely related species with similarity values of 90.5, 88.9, 88.5, 84.5 and 84.4 % for R. multihospitium HAMBI 2975 T , R. tropici CIAT 899 T , R. hainanense CCBAU 57015 T , R. miluonense HAMBI 2971 T and R. freirei PRF 81 T , respectively; digital DNA-DNA hybridization values were in the range of 26-42 %. Considering the phenotypic characteristics as well as the genomic data, it is suggested that strains S-93 T and S-62 represent a new species, for which the name Rhizobium dioscoreae is proposed. The type strain is S-93 T (=NRIC 0988 T =NBRC 114257 T =DSM 110498 T ).