| The wild hawthorn fruits were selected for isolating more effective antagonistic yeasts against apple diseases. In order to expand the sources of antagonistic yeasts and provide the material to improve antagonistic yeasts by protoplast fusion between yeast and actinomyces, creating the new approaches for screening the antagonistic yeast.Eleven antagonistic yeasts were screened from the surface of wild hawthorn fruits in vivo method, and both of them could inhibit to three target pathogens, Trichothecium roseum, Botrytis cinerea and Colletotrichum gloeosporioides. Suppressive effect was influencing in different inoculum concentration of yeast strains, challenge inoculation interval with target pathogens and different storage temperature of tested fruits by the further suppressive effect study. Four effective antagonistic yeasts, S3, A14, A2 and T1, were screened. The effective effects of four strains control apple diseases caused by three target pathogens could be observed at 108cfu/mL yeasts inoculation concentration, preinoculation of 24h and at 4℃storage condition. The control efficiency of two strains, A2 and T1, reach to 100% under the same condition. And four antagonistic yeasts in wound apple fruit could be rapid multiply, the population of them increased by 30 fold, then stabilized for the remained period of storage.The most effective antagonistic yeasts T1 was the Cryptococcus luteolus on the base of comprehensive analysis of morphological and physiological characteristics.Although no access to effective integration of strains, but it is a correct and feasible method to improve effective antagonistic yeasts through the protoplast fusion between the endophytic actinimycte SG2 and yeasts T1.I believe it was the efficient path through screening the antagonistic yeast from the wild hawthorn fruits used in vivo method, then used the protoplast fusion between the endophytic actinimycte and yeasts which have strong reproductive capacity and resistance, to obtain the more effective and more safer biocontrol pathogens. |
