%0 Journal Article %A Sørensen, Grete M. %A Wyndaele, Rita %T Effect of Transfer of Symbiotic Plasmids and of Hydrogenase Genes (hup) on Symbiotic Efficiency of Rhizobium leguminosarum Strains %D 1986 %J Microbiology, %V 132 %N 2 %P 317-324 %@ 1465-2080 %R https://doi.org/10.1099/00221287-132-2-317 %I Microbiology Society, %X Summary: Plasmid-encoded symbiotic determinants from the Rhizobium leguminosarum strain MA1 (817) with uptake hydrogenase activity (Hup+) and from the Hup− strain MC1 (18a) were mobilized by recombination with the self-transmissible plasmid pVW5JI. The symbiotic determinants were transferred by conjugation from strain MA1 to strain MC1 and to a derivative of MC1 without the symbiotic plasmid, and vice versa, thus constructing four types of transconjugants. The determinants for a total recycling hydrogenase in strain MA1 were found to be encoded on the symbiotic plasmid. Strain MC1 fixed 60% more N2 in pea root nodules, determined as mg nitrogen per plant, than strain MA1. This difference was not increased in the MC1 derivative that obtained hydrogenase activity. Plants inoculated with a derivative of strain MA1, however, where the symbiotic plasmid was replaced by that of strain MC1 had a high percentage nitrogen content. It was concluded that the symbiotic plasmid and the genetic background were more important for plant nitrogen accumulation than uptake hydrogenase. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-132-2-317