| The author had systemically studied and reported the isolation and identification of the antagonistic strain BY-3 and its effects against tomato gray mould rot and pepper anthracnose, which are expected to obtain. The biological characteristics, the physiology and biochemistry, cultivated features, biocontrol mechanism and its biocontrol effects against Botrytis cinema and Colletotrichum coccodes, were studied respectively in this paper.1 Sieving and anti-fungal activity of the antagonistic strain BY-3In the experiment, we found that both antagonistic strain BY-3 and BA-5 were inhibiting activity to tomato gray mould rot and pepper anthracnose. And the capacity of the strain BY-3 was obvious by using the method of the inhibiting zones. Thus, the strain BY-3 was regarded as the biocontrol agent to pathogens.Besides, the activity of 12 kinds of fungal pathogens was measured respectively. The results showed the strain BY-3 had certain antagonistic effect to them, especially to Botrytis sp. and Colletotrichum sp.As a whole, the antagonistic strain BY-3 is a biological agent which is tested and applied.2 The research of the antagonistic strain BY-32.1 Cultivated features of the antagonistic strain BY-3This research indicated different temperature, pH, nourishment( carbon source, nitrogen source) and different salinity to the influence of the growth of the strain BY-3.The results showed that the optimal temperature for the growth of BY-3 was 30~ 40℃. And the optimal pH was 6~6.5. Besides, the optimal cultivated time was 36~52 h. The favorite carbon source included maltase, sucrose, mannitol, glucose, lactose, and so on. The strain BY-3 can grow well in inorganic or organic substrate media containing different C or N source. Both Casein hydrolysate and ammonium nitrate can be used better than the others. Among nitrogen sources, the nitrate was the best for the cultivation of the strain BY-3.In different salinity cultivated liquid, the strain BY-3 can grow well. But while the percentage of the salinity was below 2%, the cultivated liquid was the best media for the grow of the strain BY-3.2.2 Identification of the antagonistic strain BY-3Based on the reference book, the physiology and biochemistry, cultivation of the antagonistic strain BY-3 were studied and identified. The results showed that the biocontrol strain BY-3 belonged to Bacillus licheniformis according to the morphological, physiological and biochemical characteristic as well as culture characters3 Biocontrol mechanism of the antagonistic strain BY-3Both tomato gray mould rot and pepper anthracnose were cultivated on the PDA plate which contain the culture filtrate of the biocontrol strain BY-3. After treated by the aseptic filtrate, there were a lot of vesicles like prayer beads appearing in the apex and middle of the mycelia of both pathogens. And the diameter of the vesicle was four to five times of the normal hyphae. As the time gone, the cell wall of the vesicles broken and the protoplasm from it flowed out.The spore suspension of the pathogens was treated by aseptic filtrate of the biocontrol strain BY-3.Then the spores were observed at regular intervals under the microscope The results showed that some spore tubes began to dilate and become to deformed spherical structure when cultured for 12 hours and the spherical structures began to break after cultivated for 18 hours, the protoplasm of the cell flowed out and the cells were left as empty vesicles.4 Biocontrol effects of the antagonistic strain BY-3 against B. cinerea and C. coccodesDifferent methods were used to test the inhibition of fermentation liquid and exudate filtrate of the strain BY-3 against B.cinerea Pers. ex Fr. and C. coccodes (Wallroth) Hughes. The results showed that the biocontrol effects of the strain BY-3 was better. As far as the effects were concerned, the cell culture of BY-3 was more effective than heated culture(121°C,30min) and cell-filtrate.By soaking the fermentation liquid and exudate filtrate of the strain BY-3, the biocontrol effectiveness of B.cinerea and C. coccodes was57.7~75.5% and 45.1~68.1%, respectivelyConsequently, all these results indicated that the antagonistic strain BY-3 could effectively control the diseases by all kinds of the mechanisms.
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