P-361 - COMPARISON OF THE GENETIC DIVERSITY IN RHIZOBIA ISOLATED FROM CULTIVATED AND UNCULTIVATED LEGUMES GROWN ON O‘AHU

Abstract Text: Rhizobia are nitrogen-fixing, species specific endosymbiotic bacteria that grow in root nodules of legumes. Since cultivation practices can lead to a drastic change in the environment, we hypothesize that there is a genetic difference between Rhizobial populations in cultivated and uncultivated leguminous crops on O‘ahu. Root nodules collected from multiple locations on O‘ahu were surface sterilized, and contents within the nodules were inoculated onto a semi-selective differential medium for Rhizobia. Pure cultures were established by streaking the resulting colonies resembling those of known characteristics in Rhizobia.The DNA from pure cultures were isolated and several genetic loci (16S, atpD, recA, dnaK, gyrA) were amplified, and resulting amplicons were purified and sequenced by Sanger Sequencing. The isolated Rhizobia were identified via BLAST search, and the resulting sequences of each locus were analyzed to determine the relatedness of the isolates using Clustal Omega and MEGA to produce a phylogenetic tree. Additionally, a multilocus analysis was performed to elucidate the genetic diversity of the isolated Rhizobia. While the data generated did not suggest that there was a significant genetic difference between Rhizobia isolated from cultivated and uncultivated legumes, we postulate that a larger sample size will better shed light on their genetic differences. Future work would involve a careful sampling of representative plants to determine the impact of human cultivation methods on the relationship between legumes and their rhizobial endosymbionts.