Rhizobium pongamiaesp. nov. from Root Nodules ofPongamia pinnata
Pongamia pinnatahas an added advantage of N2-fixing ability and tolerance to stress conditions as compared with other biodiesel crops. It harbours “rhizobia” as an endophytic bacterial community on its root nodules. A gram-negative, nonmotile, fast-growing, rod-shaped, bacterial strain VKLR-01Twas isolated from root nodules ofPongamiathat grew optimal at 28°C, pH 7.0 in presence of 2% NaCl. Isolate VKLR-01 exhibits higher tolerance to the prevailing adverse conditions, for example, salt stress, elevated temperatures and alkalinity. Strain VKLR-01Thas the major cellular fatty acid as C18:1 ω7c (65.92%). Strain VKLR-01Twas found to be a nitrogen fixer using the acetylene reduction assay and PCR detection of anifH gene. On the basis of phenotypic, phylogenetic distinctiveness and molecular data (16S rRNA,recA, andatpD gene sequences, G + C content, DNA-DNA hybridization etc.), strain VKLR-01T= (MTCC 10513T= MSCL 1015T) is considered to represent a novel species of the genusRhizobiumfor which the nameRhizobium pongamiaesp. nov. is proposed.Rhizobium pongamiaemay possess specific traits that can be transferred to other rhizobia through biotechnological tools and can be directly used as inoculants for reclamation of wasteland; hence, they are very important from both economic and environmental prospects.