| The Blumeria graminis f.sp.tritic of wheat is one of the major diseases of wheat in the word. It is much severe in China. But the controls to the wheat powdery mildew are chemical control and cultivating resistance-variety; and meanwhile, the variation of the physiological races is so fast. The resistance to wheat powdery mildew is lost easily, and the negative effect to environment and pesticide-resistance of chemical pesticide are more and more serious. So the new control measures are necessary, and the benefic microorganism to control wheat powdery mildew become to be hot research. So, effects of endophytic bacteria E1R-J isolated from winter wheat were studied in this thesis. The main results were as follows:1. Through the primary screening to 15 strains, the control effect of Chae,E1R-J,E1R-H,ECL5 and EM7 are better than others. The control effect of E1R-J and E1R-H are best in the 5 strains, it can be got to 80%. And through the secondary screening ,the E1R-J is chosen as the biocontrol strain.2. The bacterial suspension and fermented filtration from the antagonistic endophytic bacteria E1R-J were tested for effectiveness against Blumeria graminis f.sp. tritici, pathogen of wheat powdery mildew. Results showed that the effectiveness of the fermented filtration had been beyond 80%, better than the 40% from the bacterial suspension. The results indicated the effective substance was crude protein in fermented filtration by contrasting the protein suspension and the non-protein suspension. And more, the best concentration was tested, the bacterial suspension was 109-10 CFU/ ml, and the fermented filtration was 5 times diluted E1R-J.3. The inhibition ratio of conidia germination to wheat powdery mildew is showed: the bacterial suspension,antimicrobial protein and fermented filtration from the antagonistic endophytic bacteria E1R-J are all obviously active to the conidia germination to wheat powdery mildew. The inhibition ratio of 1% crude protein can be got to 86.44%, and the 10% fermented filtration's can be 100%; the 100μl bacterial suspension is 52.71%.4. The colonization test showed that the bacteria E1R-J could colonize in the root, stem-base and leaf of the wheat through soaking-seed,soil-mixed and dipping- root. And through the contrast of three treatment, the colonization quantity of the endophytic bacteria E1R-J is different. The best is dipping-root, the concentration is 9×10~3 CFU/g; the next is soaking-seed, the concentration is 7×10~3 CFU/g; and soil-mixed is the last one, the concentration is 5×10~3 CFU/g. With the time process, the quantity of dipping- root is to more, but the quantity of soaking-seed and soil- mixed is to decline. So the dipping-root is the best treatment to control wheat powdery mildew with the endophytic bacteria E1R-J. And it was detected after 24 days, that showed it was an endophytic bacteria.5. The endophytic bacteria E1R-J is isolated from the root of winter wheat, the optimiz- ing conditions of the fermentation are showed: the optimum media is that made of peptone 0.6%, yeast exact 0.6%, NaCl 0.3%, K2HPO4 0.02% with initial pH 4.5-9.0, culturing at 34℃,150r/m, and inoculation of seeds culture with 2%, in 100ml LB of 250ml flask, the time of seeds culture is 20~34h, and the time of fermentation for biocontrol is 48~73h.. So the concen- tration is 5.2×10~7CFU/ml.
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