【作者】 龙建友；

【导师】 吴文君；

【作者基本信息】 西北农林科技大学 ， 农药学， 2006， 博士

【摘要】 秦岭链霉菌(Streptomyces qinlingensis sp.nov.)是作者从陕西秦岭土壤中分离的一株放线菌(No.24菌株),其发酵产物对多种植物病原真菌和细菌具有强烈的抑制作用。本文对秦岭链霉菌菌株的分类地位、发酵产物的生物活性、发酵产物的稳定性、高产菌株选育、发酵条件优化进行了系统的研究。主要研究结果如下:(1)No.24菌株的形态特征、培养特征、生理生化特征、细胞壁化学成分以及16SrDNA序列研究结果表明,No.24菌株与模式菌株Streptomyces maritimus(AY247716)的16SrDNA同源性为99%。但菌株在形态特征、培养特征、生理生化特征和细胞壁化学成分等方面均不同于模式菌株。No.24菌株在酵母膏培养基上产生浅黄色的可溶性色素,孢子表面光滑,而S.maritimus菌株不产生任何可溶性色素,孢子表面不光滑,No.24菌株细胞壁含二氨基庚二酸(LL-DAP)、甘氨酸和乳糖,而S.maritimus菌株细胞壁则含L-DAP;No.24菌株在含有5%NaCl的培养基中能良好生长,而S.maritimus菌株则不能在含有5%NaCl的培养基中生长;秦岭链霉菌能同时代谢杀虫和杀菌抗生素,而S.maritimus菌株则未见代谢任何抗生素的报道。因此,建议把该菌株命名为链霉菌属的一个新种,即秦岭链霉菌(Streptomyces qinlingensis sp.nov.)。(2)室内生测结果表明,秦岭链霉菌发酵产物不但对多种常见植物病原真菌具有较强的抑菌活性,而且对多种植物病原细菌和动物病原细菌也有良好的抑制作用,表现为广谱抗菌性。抑制菌丝生长速率法生测结果表明,秦岭链霉菌发酵产物对玉米大斑病菌(Exserohilum turcicum)、苹果轮纹病菌(Macrophoma kuwatsukai)、小麦根腐病菌(Bipolaris sorokiniana)的EC50分别为238.95 mg/l,146.87 mg/l和164.09 mg/l;抑制孢子萌发法试验结果表明,秦岭链霉菌发酵产物对玉米大斑病菌和马铃薯干腐病菌(Fusarium coeruleum)的EC50分别为129.33 mg/l和184.99 mg/l。管蝶法生测结果表明,秦岭链霉菌发酵产物对枯草芽孢杆菌(Bacillus subtills)、蜡状芽孢杆菌(Bacillus cereus)、水稻白叶枯病菌(Xathomonas oryzae pv.oryzae)和链球菌(Streptococcus)的抑菌圈直径分别为24mm,23 mm,19.8 mm和19.0 mm。盆栽试验结果表明,秦岭链霉菌发酵产物对小麦白粉病(Blumeria graminis)、黄瓜霜霉病(Pseudoperonospora cubensis)和番茄灰霉病(Botrytis cinerea)的保护效果分别为76.1%,63.9%和61.1%,治疗效果分别为70.8%,59.7%和66.9%。田间试验结果表明,秦岭链霉菌发酵产物对小麦白粉病、黄瓜霜霉病和番茄灰霉病的防治效果分别为52.73%,64.98%和74.95%。(3)以枯草芽孢杆菌为指示菌,测定了秦岭链霉菌发酵液的稳定性。发现发酵液对光照、热和酸均较稳定,加热到80℃仍不丧失活性,在pH2～6的1mol/l的HCl溶液更多还原

【Abstract】 Streptomyces qinlingensis sp.nov. was isolated by pesticide institute of Northwest A&F University from the soil of qinling mountainous areas in shaanxi province, China. The fermentation products of Streptomyces qinlingensis sp.nov. exhibited strong fungicidal activity against pathogenic fungi and bacteria. This dissertation focused particularly on studies on the strain identification, the stability, bioactivity of fermentation broths, mutation breeding, protoplast fusion, fermentation condition optimization, the main results are as follows:The 16SrDNA sequence showed that the homology between strain No.24 and Streptomycesmaritimus was 99%. However,the morphological ,cultural,physiological and biochemical characteristics,the chemical components of the cell walls of the strain were different from those of the model strain. Strain No.24 produced simple yellow soluble pigment in Yeast extract agar, had LL-DAP and lactose in cell wall,could grow in the medium contained 5% NaCl. But Streptomyces maritimus produced no pigment in medium, had L-DAP in cell wall, and could not grow in 5% NaCl medium. So, strain No.24 was identified as representing a novel species of Streptomyces, which the name Streptomyces qinlingensis sp.nov. is proposed.The fungicidal activity of fermentation products of Streptomyces qinlingensis sp.nov.against pathogenic fungi and bacteria had been studied. The results of the inhibition rate of mycelium growth showed that the fermentation products had high inhibition rate against Exserohilum turcicum,Macrophoma kuwatsukai and Bipolaris sorokinana. and the EC50 values was 238.95 mg/l, 146.87 mg/l and 164.09 mg/l, respectively. The results of the inhibition of spore germination indicated that the fermentation products exhibited obvious inhibition rate against Exserohilum turcicum and Fusarium coeruleum, the EC50 values was 129.33mg/ml and 184.99mg/ml. In the bioassay of the fermentation product against Bacillus更多还原