Isolation And Characteristics Of Antifungal Proteins From Strain TL2(Bacillus Subtilis)

The strain TL2 isolated from tea leaves was identified as endophytic Bacillus subtilis and could strong control tea disease caused by P. theae. The stain protein was isolated and purified with proteome such as two-dimensional gel electrophoresis, and identified with PMF and MALDI-TOF-TOF-MS.The result demonstrated that most active elements of out-membrane-secreted protein could be deposited by 30%-70% ammonium sulfate and antifungal protein could be included in depositional protein sample by 50%-70% ammonium sulfate. The protein also be induced by the metabolites of P.theae. Meanwhile, the strain TL2 could secrete antifungal proteins to inhibit the mycelial growth and the conidia germination, thus restricting the invasion and development of the pathogen and decreasing the extent of the disease.In this experiment, clear and obviously distinct protein pots were chosen for further PMF and MALDI-TOF-TOF-MS anlysis. The result demonstrated that: 10 protein pots were successfully identified, one among them was a new protein extracellular neutral protease, This protease could inhibit several fungal pathogens, such as F.oxysporum f.sp and Rhizoctonia.solani. Furthermore, the subtilisin is a kind of serine proteases, which is the main material of many defend strain to kill drone. For example, Trichoderma spp, Metarhizium spp, Arthrobotrys oligospora, Clonostachys rosea could produce serine protease to degrade the cell wall or body wall of host.The test of antifungal proteins isolated from the strain TL2 inclaimed that various proteins secreted by strain TL2 were proved to have strong antagonism to P. theae. BSPT-P2 was proposed to be one of dominating protein, which had inhibition to P. theae and could be strongly induced by the fermentation of P. theae. BSPT-P2, which MW was 32KDa, was tested to have strong tolerant to heat and UV light, was steady from pH 6.0 to pH 9.0.