Rhizobium pusense sp nov., isolated from the rhizosphere of chickpea (Cicer arietinum L.)

A novel bacterial strain, designated NRCPB10(T), was isolated from rhizosphere soil of chickpea (Cicer arietinum L.) in Pusa, New Delhi, India. The 16S rRNA gene sequence of strain NRCPB10T showed highest similarity (98.9%) to that of Rhizobium radiobacter NCPPB 2437(T), followed by Rhizobium larrymoorei AF3-10(T) (97.7%) and Rhizobium rubi IFO 13261(T) (97.4%). Phylogenetic analysis of strain NRCPB10(T) based on the housekeeping genes recA and atpD confirmed its position as distinct from recognized Rhizobium species. Levels of DNA DNA relatedness between strain NRCPB10(T) and R. radiobacter ICMP 5785(T), R. larrymoorei LMG 21410(T) and R. rubi ICMP 6428(T) were 51.0, 32.6 and 27.3%, respectively. Cellular fatty acids of strain NRCPB10(T) were C-18:1 omega 7c (58.9%), C-16:0 (15.5%), C-19:0 cyclo omega 8c (11.5%), iso-C-16:1 (5.8%), C-16:0 3-OH (4.5%), C-16:1 omega 7c (2.1 %) and C-18:0 (1.3%). The G+C content of the genomic DNA of strain NRCPB10(T) was 59.0 mol%. Strain NRCPB10(T) did not nodulate chickpea plants or induce tumours in tobacco plants. Phenotypic and physiological properties along with SDS-PAGE of whole-cell soluble proteins differentiated strain NRCPB10(T) from its closest phylogenetic neighbours. On the basis of data from the present polyphasic taxonomic study, strain NRCPB10(T) is considered to represent a novel species of the genus Rhizobium, for which the name Rhizobium pusense sp. nov. is proposed. The type strain is NRCPB10(T) (=LMG 25623(T)=JCM 16209(T)=NCIMB 14639(T)).