Studies on Molecular characterization of Rhizobium spp. Isolates from Agricultural soil of M.P

Abstract

Nitrogen fixation in leguminous plants by rhizobia, gram-negative symbiotic bacteria, is important in
natural ecosystems and for agriculture. This is because the rhizobia are capable of utilizing dinitrogen
directly with their nitrogenases, whereas the plants have to get nitrogen in a chemically reduced form,
which can be costly. Both the bacteria and their host plants are involved in determining host specificity
and the interaction between the host plant and the rhizobial bacteria is often highly specific. The aim of
this study was to study diversity of Rhizobium spp. in agricultural lands of Madhya Pradesh.
Physicochemical properties of soil were studied using standard methods while molecular methods used to
study diversity within Rhizobium species. Further, population analysis of Rhizobium species in relation to
genetic diversity was carried out using 16S rDNA-RFLP PCR. Rhizobium were identified and genetically
by determining the %G+C content of the whole genome, followed by Restriction enzyme (Mbo I, Hap II,
Taq I, Msp I, Cfo I, Nde II, Dde I, Rsa I) treatment of Polymerase Chain Reaction (PCR) amplified
product of 16S rDNA segment was performed. The sequences recognized by the restriction enzymes are
distributed at variable intervals in the genome of an organism and also vary in number. The separation
carried out by electrophoresis (1.6-2% agarose gel) resulted in specific banding pattern differing within as
well as among different species.