【摘要】 构建出费氏中华根瘤菌嘌呤合成酶基因purL的基因置换载体pHN70 1 ,purL内部NotⅠ XhoⅠ片段被luxAB基因取代 ,造成正常基因的破坏。用该载体对野生型费氏中华根瘤菌HH1 0 3进行purL的基因置换 ,筛选到腺嘌呤缺陷型突变株P82 5。波动实验和连续转接试验结果表明该突变菌株表型十分稳定。purL表达载体pBBR PG在P82 5中可恢复其在基本培养基上的生长情况 ,证明突变株确实为purL单基因破坏。盆栽结瘤实验结果表明 ,该突变株只能侵染大豆根系形成不固氮的根瘤更多还原

【Abstract】 The Sinorhizobium fredii purL gene replacement vetcor pHN701 was constructed. The Not Ⅰ Xho Ⅰ fragment inside purL was replaced with luxAB , resulting a mutant purL . The purL gene replacement in wide type Sinorhizobium fredii HH103 was performed with pHN701, and the purine mutant P825 was screened. Fluctuation experiment and continuous reinoculation experiment showed that P825 was a very stable purine auxotroph mutant. Mutant P825 could be complemented by purL expressing vector pBBR PG to grow in minimal media, which confirmed that P825 was the result of mutagenized purL gene. In pot plant test, this mutant could infect legume plant, but only form defective nodules.更多还原