Skip to main content
ARS Home » Research » Publications at this Location » Publication #122479
Title: NITROGEN FIXING NODULES WITH ENSIFER ADHAERENS HARBORING RHIZOBIUM TROPICI SYMBIOTIC PLASMIDS

Author
item ROGEL, M - CUERNAVACA MEXICO
item HERNANDEZ-LUCAS, ISMAEL - CUERNAVACA MEXICO
item Kuykendall, Larry
item BALKWILL, DAVID - FL STATE UNIV TALLAHASSEE
item MARTINEZ-ROMERO, ESPERANZA - CUERNAVACA MEXICO

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: In crop legumes, competition between indigenous strains of bacteria and the inoculant strain typically limits nodule occupancy by the symbiotically elite inoculant strain to no more than 20% in the first year of inoculation. Recombination between, or hybrid strain formation among strains of rhizobia and their wild non-nodulating relatives in the soil, is sperhaps one way of obtaining inoculant-quality strains that are more competitive. Therefore, in this study, we transferred the symbiosis controlling plasmids from a Rhizobium strain to the bacterial close relative Ensifer that is a predator of other bacteria in the soil. The transconjugants, with an Ensifer genome and Rhizobium symbiotic plasmids, nodulated and fixed nitrogen as expected but these recombinant strains were unfortunately not any more competitive than Rhizobium but rather, in fact, they were less competitive. This information will be of interest to researchers involved with defining what makes rhizobia competitive.

Technical Abstract: Ensifer adhaerens is a soil bacterium that attaches to other bacteria and may cause their lysis. Based on the sequence of its SSU rRNA gene, E. adhaerens is related to Sinorhizobium spp. E. adhaerens ATCC33499 did not nodulate Phaseolus vulgaris (bean) or Leucaena leucocephala but with the symbiotic plasmids from Rhizobium tropici CFN299 formed nitrogen fixing nodules on both hosts. The nodule isolates were identified as E. adhaeren by growth on selective media.