利用原生质体融合技术选育农抗120高产菌株及应用的研究

利用TF-120和KT-739菌株理化特性相似、抗性互补、届者生长速度快等特点,进行了原生质体的形成、再生及其融合的研究,从近千个融合子中选育出一株FR-220。经鉴定,确认FR-220为农抗120高产菌株。工厂中试结果,其发酵单位可以提高一倍,由6000～8000μg/ml增加到14000～17000lμg/ml,相当于生产成本降低一半。1988-1089年田间防治瓜果蔬菜上的白粉病、炭疽病、枮萎病,试验示范面积2000亩,防效达70～90％,增产20～25％,扩大推广20万亩。

SELECTION OF A HIGH-YIELD STRAIN OF AGRICULTURAL ANTIBIOTIC 120 BY PROTOPLAST-FUSION TECHNIQUES

Agricultural Antibiotic 120 (AA 120) is a product of an actinomycete, Streptomyces hygrospinosus var. beijingensis. Two strains of the actinomycete, TF-120 and KT-739, were found to have similar biophysical and chemical properties and complementary biological activities against target pathogens. The latter strain had higher growth rate. Protoplast formation, regeneration, and fusion of the protoplast of the two strains were achieved in the laboratory. A new strain, FR-220, was then selected from ca. 1,000 recombinants. Results of the laboratory analysis and fermentation trials showed that the new strain is a stable, high-yielding and effective control agent against the target pathogens. The fermentation efficacy in the production of AA 120 was increased from 6,000-8,000 ug/ml by using strain TF-120 to 14,000-17,000 ug/ml by using FR-220, resulting in a 50% reduction of the production cost. In the field trials in a total area of 133 ha, spray of AA 120 produced with the new strain gave 70-90X control effect against powdery mildew, anthracnose, and wilt disease on melons, fruit trees and vegetables. During 1988-1989, AA 120 produced with the new strain was applied in an area of 13,300 ha.