中文摘要：

为研究从玫瑰黄链霉菌Men-myco-93-63中克隆到的,与天蓝色链霉菌M 145中的一个重要负调控基因nsd A基因同源的nsdA（mgh）基因的功能,本文构建了nsd A（mgh）基因破坏型重组质粒pSRNA2500（pKC1139：：1.5 kb nsdA（mgh）：：1.0 kb Km-r）,转化ET12567（pUZ8002）获得接合转移供体菌ET12567（pUZ8002,pSRNA2500）,通过接合转移将重组质粒导入玫瑰黄链霉菌Men-myco-93-63中。在高温和抗生素双重筛选压力下,筛选得到表型为Am-sKm-r的nsd A（mgh）基因阻断突变株,通过PCR、Dot bloting和Southern blotting验证了突变株中的nsdA（mgh）基因已被正确阻断。与出发菌株相比,突变株在摇瓶水平上对棉花黄萎病菌的抑制能力提高了一倍。

英文摘要：

Insertional mutagenesis is a widely used method to determine the function（s） of a gene. To study the function（s） of the gene nsdA（mgh） in Streptomyces roseoflavus, a homologous recombination vector pSRNA2500 was structured in this paper. The recombination donor vector was then transformed into Strempomyces roseoflavus strain Men-myco-93-63 by conjugative transfer. The transformants were subjected to selection under the pressure of high temperature and appropriate antibiotics. As a result, several disrupted mutants of nsdA（mgh） gene, with a phenotype of Am-sKm-r, were isolated and verified using PCR and Dot-blotting and Southern blotting hybridization methods. Functional analysis showed that the disrupted mutants of nsdA（mgh） had a two-fold higher inhibition against Verticillium dahlia Kleb than that of the wild strain Men-myco-93-63, which all will provide a new study route for future research about positive and negative regulator in Men-myco-93-63.