Study On Endophytic Bacteria (Bacillus Subtilis) From Tea Plant

There were 14 Bacillus strains isolated from tea plant, which were tested to have strong antagonism to pathogens of tea leaf spot diseases. Strain TL2 was identified to be Bacillus subtilis.The strains were proved to have ability to colonize inside of the tea plant, to have antagonism to some plant pathogens, to have control effect on tea leaf spot disease, also to have ability to degradate cypermethrin, among of which strain TL2 had stronger ability.It was tested that the bacteria could be isolated from tissues of root tip, main root, caudex, stem, lower leaf, upper leaf of tea plant in order, and community quantity of bacteria in tea plant was decreased gradually with the diversity index of endophytic bacteria in tea plant reducing, by the time after strain TL2 was inoculated. The bacterial cells of strain TL2 were proved to mainly distribute in intercellular substance of sclerenchyma in root, intercellular substance of collenchyma and vascular bundle in stem, leaf stomatal apparatus, intercellular substance of epidermal cell and collenchyma in leaf.Changing the community quantity and diversity index of endophytic bacteria in tea plant by inhabiting the ecological niche in tea plant, inhibiting the growth of hyphal and the germination of conidiospore of Pestallozzia theae by secreting the antifungal proteins, regulating the activities of SOD, POD, CAT, PAL, β-1,3-glucanases and exo-chitinases in tea plant when P. theae was inoculated, were proposed to be the key mechanisms of strain TL2 on controlling tea leaf spot disease.Various proteins secreted by strain TL2 were proved to have strong antagonism to P. theae. BSPT-P1 was proposed to be one of dominating proteins, which had inhibition to P. theae and could be strongly induced by the fermentation of P. theae. BSPT-P1, its MW was 56KDa, was tested to have strong tolerant to heat and UV light, also be steady with pH 6.0 to pH 9.0.