Depolarization of alfalfa root hair membrane potential by Rhizobium meliloti Nod factors.
Although much is known about the bacterial genetics of early nodulation, little is known about the plant cell response. Alfalfa root hair cells were impaled with intracellular microelectrodes to measure a membrane potential depolarizing activity in Rhizobium meliloti cell-free filtrates, a plant response dependent on the bacterial nodulation genes. The depolarization was desensitized by repeated exposure to factors and was not observed in a representative nonlegume. A purified extracellular Nod factor, NodRm-IV(S), caused membrane potential depolarization at nanomolar concentrations. This rapid single-cell assay provides a tool for dissecting the mechanisms of host cell response in early nodulation.
Ehrhardt
D W
DW
Department of Biological Sciences, Stanford University, Stanford CA 94305, USA.
Atkinson
E M
EM
Long
S R
SR
D008070:Lipopolysaccharides / Q000494:pharmacology*; D000455:Medicago sativa / Q000166:cytology / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D016962:Sinorhizobium meliloti / Q000502:physiology
D008070:Lipopolysaccharides; C092082:Nod factor IV, Rhizobium meliloti