ISOLATION AND CHARACTERIZATION OF PLASMID DNA FROM RHIZOBIUM IN THE ROOT NODULES OF GROUNDNUT

ABSTRACT

Groundnut (Arachis hypogaea L.) is a legume crop that is grown for its edible nuts. The root nodules of groundnut are formed by a symbiotic relationship between the groundnut plant and the bacterium Rhizobium. Rhizobium bacteria are able to fix nitrogen in the soil, which is essential for the growth of the groundnut plant. Within the rhizobium, on a cellular level, are Plasmids. These plasmids are small, circular DNA molecules that are found in bacteria. This study investigated the isolation and characterization of plasmid DNA from Rhizobium in the root nodules of groundnut. The root nodules were harvested from healthy plants and the bacteria were extracted. The extracted bacteria were then subjected to a series of procedures to isolate the plasmid DNA. The plasmid DNA is characterized by Gel electrophoresis method which involved the separation of DNA fragments by size whereby the DNA will migrate through the gel according to its size, with the smaller fragments moving faster than the larger fragments. The results of the study showed that the Rhizobium bacteria in the root nodules of groundnut contained a number of plasmids and play roles in the symbiotic relationship between groundnut plants and Rhizobium bacteria.