Abstract
The interaction between rhizobia and other nodule associated bacteria assist to mitigate nutrient stress in leguminous plants by fixing atmospheric nitrogen and synthesizing plant growth regulators. Beneficial effects of microbial inoculants emphasize the need for further research and their use in modern agriculture. The present work describes the isolation, identification, plant growth promoting properties and phylogenetic analysis of nodule associated bacteria from Mimosa pudica L. Isolation and characterization of nodule associated bacteria were done according to standard procedures. Molecular characterization of the isolates was performed using 16S ribosomal RNA. Plant growth promoting ability was analyzed by quantifying the levels of Indole acetic acid. Evolutionary distance and relatedness was analyzed using neighbor joining method. Rhizobium sp. CU8 and three other co-resident non-rhizobial nodule associated bacteria (Bacillus cereus MY5, Ralstonia pickettii MY1 and Lactococcus lactis MY3) exhibiting nitrogen fixation, plant growth promotion and other potential microbial activities were characterized. Phylogenetic analysis revealed the genetic relatedness and evolutionary significance of Rhizobium sp. CU8 and other co-inhabitant non-rhizobial nodule associated bacteria from M. pudica. Present study identified the four isolates as potential biofertilizers due to their nitrogen fixing and growth promoting characteristics. L. lactis MY3 is the first co-resident nitrogen fixer and plant growth promoter reported from the root nodules of M. pudica.
Characterization of plant growth promoting rhizobia from root nodule of Mimosa pudica grown in Assam, India
