Isolation and characterization of plant synergistic bacteria capable of degrading xenobiotics from oil spillage sites

Oil spillage sites primarily contain various types of hydrocarbons, such as linear chain, polycyclic, and aromatic compounds, posing several detrimental effects on plants. Results from our previous study showed an alteration of various metabolomic parameters, indirectly resulting in an observable decline of growth in the mung seedlings upon incubation with phenol, toluene, xylene, and hexane. This study evaluates the role of these compounds upon plant growth and focusses to mitigate the effect of the same, using some isolated plant synergistic bacteria. We isolated Proteus sp., Streptococcus sp., and Enterococcus sp., and tested the synergism of them in mung seedlings (Vigna radiata) by hydroponics. Treatment with the above-mentioned compounds significantly reduced the root and shoot length of the seedlings when compared to the control. The bacterial treatment helped in reducing the adversity due to the xenobiotic insult, by improving the root shoot length of the treated seedlings. Proteus sp. was found to be the most promising among other isolates. In another experiment, plasmid profiling of the bacterial isolates was done, yielding a band of 4.5 kb common for all, serving as a clue to be the most probable plasmid responsible for the degradation of the compounds. Results from this study clearly indicate that Proteus sp. can be explored further for its plant synergism and xenobiotic degradative capability to exploit its potential in oil spillage land reclamation and establishing vegetation.