Transfer of an Indigenous Plasmid of Rhizobium loti to other Rhizobia and Agrobacterium tumefaciens

Publisher Website
Google Scholar
Abstract
R. loti strains NZP2037 and NZP2213 were each found to contain a single large plasmid: pRlo2037a (240 megadaltons) and pRlo2213a (120 megadaltons), 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 N2 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 A. 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 neccessary for effective nodulation of L. pedunculatus, were not carried on pRlo2037a. Thus, nodulation, N2 fixation and flavolan resistance genes evidently are not present on the large plasmid in R. loti strain NZP2037.