Pankhurst C E, Broughton W J, Wieneke U
J Gen Microbiol. 1983 Aug;129(8):2535-43. doi: 10.1099/00221287-129-8-2535.
Rhizobium loti strains NZP2037 and NZP2213 were each found to contain a single large plasmid: pRlo2037a (240 MDal) and pRlo2213a (120 MDal), respectively. Plasmid DNA present in crude cell lysates of each strain and purified pRlo2037a DNA did not hybridize with pID1, a recombinant plasmid containing part of the nitrogen fixation (nif) region of R. meliloti, indicating that nif genes were not present on these plasmids. The transposon Tn5 was inserted into pRlo2037a and this plasmid was then transferred into R. leguminosarum, R. meliloti and Agrobacterium tumefaciens. All transconjugants failed to nodulate Lotus pedunculatus, suggesting that the ability to nodulate this legume was also not carried on pRlo2037a. Transfer of pRlo2037a to R. loti strain NZP2213 did not alter the Nod+ Fix- phenotype of this strain for L. pedunculatus. Determinants for flavolan resistance, believed to be necessary for effective nodulation of L. pedunculatus, were not carried on pRlo2037a. These data suggest that nodulation, nitrogen fixation and flavolan resistance genes are not present on the large plasmid in R. loti strain NZP2037.
发现百脉根根瘤菌菌株NZP2037和NZP2213各自含有一个大质粒：分别为pRlo2037a（240 MDal）和pRlo2213a（120 MDal）。每个菌株的粗细胞裂解物中存在的质粒DNA以及纯化的pRlo2037a DNA与pID1不杂交，pID1是一种含有苜蓿根瘤菌固氮（nif）区域部分的重组质粒，这表明这些质粒上不存在nif基因。转座子Tn5插入到pRlo2037a中，然后将该质粒转移到豌豆根瘤菌、苜蓿根瘤菌和根癌土壤杆菌中。所有的接合子都不能使百脉根结瘤，这表明使这种豆科植物结瘤的能力也不在pRlo2037a上。将pRlo2037a转移到百脉根根瘤菌菌株NZP2213中并没有改变该菌株对百脉根的结瘤阳性固氮阴性表型。据信对百脉根有效结瘤必需的黄烷抗性决定因素不在pRlo2037a上。这些数据表明，百脉根根瘤菌菌株NZP2037中的大质粒上不存在结瘤、固氮和黄烷抗性基因。
