【作者】 陈立梅；

【导师】 杨信东； 李启云；

【作者基本信息】 吉林农业大学 ， 植物病理学， 2006， 硕士

【摘要】 本研究采用稀释平板划线分离法从土壤中分离到11株放线菌，并采用平板对峙法针对防治玉米弯孢菌对这11种放线菌进行初步筛选和再次筛选，经初步平板筛选后，有5株放线菌对玉米弯孢菌有拮抗作用，其中有3株表现较强的抑菌活性。经发酵液再次筛选发现在这5株菌株中BPS2对玉米弯孢菌的抑菌效果最佳。随后对BPS2放线菌菌种的初步鉴定、摇瓶最适发酵条件及田间防治效果等内容进行了探索。 通过对菌株BPS2的形态和生理生化特征以及16S rDNA序列分析的结果表明，该菌株的16S rDNA序列与S．purpurascens DSM 40310T同源性最高，其同源性高达97％，但该菌株与S．purpurascens DSM 40310T在形态特征、生理生化特性上均有较大差异。因此，初步鉴定菌株BPS2可能为一个新种或变种，并将其命名为Streptomyces tumenensis BPS2。抑菌谱测定表明BPS2放线菌的发酵液对多种真菌如：禾谷镰刀菌病菌(Fusarium graminearum)、玉米大斑病菌(Exserohilum turcicum)、大豆灰斑病菌(Cercosporidium sojinum)、黄瓜黑星病菌(Cladosporium cucumerinum)、番茄叶霉(Fulvia fulva)、番茄早疫病菌(Alternaria solani)、烟草赤星病菌(Alternaria alternata)、葱紫斑病菌(Alternaria porri)、大豆灰斑(Cercosporidium sojinum(Hara)Liu & Guo)、茄腐镰刀菌(Fusarium solani)及对革兰氏阳性菌金黄色葡萄球菌(Staphvlococcus aureaus)、枯草杆菌(Bacillus subtilis)；革兰氏阴性菌大肠杆菌(Escherichia coli)、结核杆菌(Mycobecterium tuberculosis)都表现出不同程度的抑菌活性。 试验还对影响菌株BPS2抑菌活性的发酵条件进行了优化，确定其培养基最佳配方为：蔗糖2.0％，玉米粉2.0％，黄豆饼粉3.0％，蛋白胨0.6％，硫酸铵0.3％，磷酸二氢钾0.1％，氯化钠0.1％，碳酸钙0.3％，培养初始pH值为自然。其适宜的发酵条件是：种龄28h、接种量6％、装液量为30ml/250ml三角瓶，发酵周期为60h、摇床转速200r/min、发酵温度28℃、pH为自然。 通过菌株BPS2发酵液进行的对玉米弯孢菌叶斑病防效实验表明，田间接种前24h喷施发酵原液和发酵液5倍稀释液，对玉米弯孢菌叶斑病有显著的防治效更多还原

【Abstract】 Eleven actinomycetes strains were isolated from different soil samples using dilution method Plate resist method combined with growth speed method was applied to select antagonists. After primary selection by plate resist method, 5 strains were acquired among which 3 strains behaved stronger inhibition activities. In the following selection, 1 strain named BPS2 showed the strongest inhibition activity. The fermentation filtrate showed a high inhibition activity against maize leaf spot caused by Curvularia lunata. Then, identification, optimum fermentation condition and antifungal test against Curvularia lunata were studied in this reportMorphological, physiological and biochemical tests and 16S rDNA sequence analysis were made to identify the strain BPS2. The results indicated that the 16S rDNA of BPS2 showed the highest homology to Streptomyces purpurascens with 97 % . But the morphological and physiological and biochemical character between them revealed distinctness. Based on the polyphase taxonomical views, BPS2 was identified as a new special of streptomyce and was denominated Streptomyces tumenensis BPS2. Its antifungal spectrum includes many plant pathogenic fungi such as Fusarium graminearum, Exserohilum turcicum, Cercosporidium sojinum, Cladosporium cucumerinum, Alternaria solani, Alternaria alternate, Alternaria alternate, Alternaria porri, Cercosporidium sojinum （Hara） , Fusarium solani. The fermentation filtrate showed a high inhibition activity against Gram-positive bacteria such as Staphylococcus aureaus, Bacillus subtilis; Gram-negative bacteria such as Escherichia coli, Mycobecterium tuberculosis.The optimum conditions were determined, which included sucrose 2.0 %, cornmeal powder 2.0 %, soybean powder 3.0 %, peptone 0.6 %, Ammonia sulfate 0.3 %, KH₂PO₄0 1 %, NaCl 0.1 %, CaCO₃ 0.3% in 1000 ml medium, the optimum initial pH was natural pH 6. Optimum fermentation condition of strain BPS2 was also determined, which indicated that antibiotics of strain BPS2 had strong inhibition activity with 28 h seed age, 6 % inoculation volume （v/v）, the medium volume in the flask was 30 ml/250 ml, fermentation period was 60 hour, 200 r/min, 28℃fermentation temperature and pH was natural.Through control efficiency test, it indicated that the fermentation liquid of strain BPS2 had更多还原