利用豌豆根瘤菌（Ｒｈｉｚｏｂｉｕｍｌｅｇｕｍｉｎｏｓａｒｕｍ）ＤＮＡ和好气性固氮菌（Ａｚｏｔｏｂａｃｔｅｒｖｉｎｅｌａｎｄｉｉ）ＤＮＡ之间的同源性，将ｎｉｆＤ基因插入了Ｔｎ５的豌豆根瘤菌突变株来诱导在ｎｉｆＤ基因上产生变异的Ａ．ｖｉｎｅｌａｎｄｉｉ突变株．先将豌豆根瘤菌的固氮结构基因ｎｉｆＤＨ克隆到大肠杆菌质粒ＰＲＫ２９０形成新的质粒ＰＲＫ２５０９，在协助质料ＰＲＫ２０１３的帮助下转入Ａ．ｖｉｎｅｌａｎｄｉｉ．对于筛选出的失去固氮能力的Ａ．ｖｉｎｅｌａｎｄｉｉ突变株进行测定，检测无细胞提取物中不同固氮酶组分的活性以及固氨酶蛋白组分的免疫性．结果表明，利用此基因转移系统查得到Ａ．ｖｉｎｅ；ａｎｄｉｉｅ的ｎｉｆ突变株．一些突变株的体外固氨酶活性非常低，加入纯化的固氨酶的不同组分可以增加其活性．在测定的突变株中，固氨酶的两种组分仍然存在，说明Ｔｎ５插入的位点是染色体上其它与固氮酶活性有关的位点． Using the homology between Rhizobium leguminosarum DNA and Azotobacter vinelandii DNA, a nifD gene was inserted into a mutant pea Rhizobium strain of Tn5 to induce a mutation in the nifD gene. vinelandii mutant. Firstly, nifDH, a nitrogen-fixing structural gene of pea rhizobia, was cloned into Escherichia coli PRK290 to form a new plasmid PRK2509, which was transferred to A with the help of PRK2013. vinelandii. For the screening of the ability to lose nitrogen fixation A. vinelandii mutant strain was tested for the activity of different nitrogenase components in the cell-free extract and for the immunity of the protein components of the ammonia-fixing enzyme. The results show that the use of this gene transfer system found A vine; andiie’s nif mutant. Some mutant strains have very low in vitro aminotransferase activity and the addition of different components of purified aminotransferase increases their activity. In the mutants tested, the two components of the aminotransferase still exist, indicating that the insertion site of Tn5 is the site on the chromosome that is related to the activity of the nitrogenase.