Antagonism of dominant bacteria in tea rhizosphere of Indian Himalayan regions

Some parts of the Indian Himalayan region are covered by established and abandoned tea bushes. Rhizospheric soils of these plants were studied for bacterial dominance and antagonism. Amongst bacteria, Bacillus (up to 45%) and Pseudomonas (up to 85%) were found to dominate the rhizosphere of established and abandoned tea bushes, respectively. Amongst the species, B. subtilis and B. mycoides appeared to be closely associated with roots of established tea bushes, and the rhizosphere of abandoned tea bushes was dominated by Pseudomonas putida. Four bacterial strains each of B. subtilis and P. putida were selected on the basis of maximum antibacterial activity. Incubation of indicator strains with different concentrations of bacteriocin exhibited bactericidal activity. Various species of Bacillus and Pseudomonas behaved antagonistically amongst themselves due to the production of bacteriocins under in vitro conditions.