【摘要】 A-因子是灰色链霉菌次级代谢和形态分化的自调节因子,研究发现,afsA家族基因编码链霉菌A-因子及其类似物合成过程中的一种关键酶。前期本研究将玫瑰黄链霉菌Men-myco-93-63抗生素合成基因簇定位于其线性质粒pSR47上,生物信息学分析发现pSR47含有afsA家族基因。为了明确afsA在玫瑰黄链霉菌中的作用,本研究通过构建afsA基因敲除载体,应用接合转移方法将其转入玫瑰黄链霉菌,筛选获得发生同源重组的afsA缺失突变株。试验发现缺失突变株只产生少量气生菌丝及孢子,并且丧失对指示菌的拮抗作用,这说明afsA基因参与控制玫瑰黄链霉菌Men-myco-93-63的形态分化及抗生素产生。更多还原

【Abstract】 A-factor(autoregulatory factor)induces streptomycin production and sporulation in Streptomycesgriseus.Gene of afsAfamily encodes a kind of key enzyme during the synthesis of A-factor and its analogs in Streptomyces.In our previous work,antibiotic biosynthetic gene cluster has been positioned on linear plasmid pSR47 of S.roseoflavu Men-myco-93-63.Bioinformatic analysis revealed that plasmid pSR47 contains afsAfamily gene.In order to clarify the role of afsAin S.roseoflavu Men-myco-93-63,knockout vector used for deletion of afsAwas constructed,transferred into S.roseoflavu Men-myco-93-63 by conjugation,and afsA-deletion mutant strain in which homologous recombination has occured was obtained.It was found that deletion mutant produced only a small amount of aerial hyphae and spores,and lost antagonism against indicator Verticillium dahliae,which shows that afsAinvolves in morphological differentiation and antibiotic production of S.roseoflavu Men-myco-93-63.更多还原