Protoplast Fusion Of Hyperparasitic Streptomyces F46 And Actinomyces SC11

The protoplast fusion between hyperparasitic Streptomyces strain F46 and Actinomyces strain SC11 was studied in order to improve the effect of wild actinomyces strains to control plant diseases, solve the problems in application of the biocontrol strains, explore the method of protoplast fusion and get the recombinants with some excellent characteristics of both parents.The conditions of protoplast formation and regeneration were optimized by measuring the dried mycelia, counting the protoplasts with microscope and calculating the regeneration rate. The results showed that strains F46 & SC11 can form high quantity and quality mycelia which were easy to prepare protoplast when they grew respectively in liquid medium with 20% & 10% sucrose and 1.5% & 1.0% Gly for 96-100h; High quality protoplasts of strains SC11 & F46 can be gained respectively in 5mg·mL-1 lysozyme and enzyme mixing 10mg·mL-1 lysozyme with 10mg·mL-1 snailase for 90min and 120min.Inactivating conditions of strains F46 & SC11 were determined by survival rate. In 60℃, strains F46 & SC11 protoplasts were treated for 60min and 15min respectively; In the distance of 15cm, 15min and 7min radiation treatments to strains F46 & SC11 protoplast with 20W UV-light were the best.Following all conditions optimized, protoplasts'preparation, fusion and regeneration were done and nine recombinant strains were selected according to colony characteristics of strains. Recombinant strains F-S5, F-S15, F-S16 and F-S17, which were better than strain SC11, were gained by comparing the suppressive ability with the parents to the target pathogens.According to the inhibiting mechanism to the target pathogens, the stability of fusants in inheritance, the morphological characteristics, the cultural properties on different media, biochemical and physiological characteristics and growth speed of mycelium, the fusants were identified if they were true. The result showed that there were the different as well as the same between the fusants and strains F46 & SC11. Conclusion was gotten that the recombinants inherited characteristics of the parents and produced some new properties. A single band about 1500bp were gained in all strains by amplifying 16S rDNAs with universal...