title: Nod factor-induced expression of leghemoglobin to study the mechanism of NH4NO3 inhibition on root hair deformation.
abstract: Nod factors secreted by Rhizobium leguminosarum by, viciae induce root hair deformation, the formation of nodule primordia, and the expression of early nodulin genes in Vicia sativa (vetch). Root hair deformation is induced within 3 h in a small, susceptible zone (+/-2 mm) of the root. NH4NO3, known to be a potent blocker of nodule formation, inhibits root hair deformation, initial cortical cell divisions, and infection thread formation. To test whether NH4NO3 affects the formation of a component of the Nod factor perception-transduction system, we studied Nod factor-induced gene expression. The differential display technique was used to search for marker genes, which are induced within 1 to 3 h after Nod factor application. Surprisingly, one of the isolated cDNA clones was identified as a leghemoglobin gene (VsLb1), which is induced in vetch roots within 1 h after Nod factor application. By using the drug brefeldin A, it was then shown that VsLb1 activation does not require root hair deformation. The pVsLb1 clone was used as a marker to show that in vetch plants grown in the presence of NH4NO3, Nod factor perception and transduction leading to gene expression are unaffected.
authors.affiliation: Department of Molecular Biology, Agricultural University, Wageningen, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Heidstra
authors.forename: G
authors.initials: G
authors.lastname: Nilsen
authors.forename: F
authors.initials: F
authors.lastname: Martinez-Abarca
authors.forename: A
authors.initials: A
authors.lastname: van Kammen
authors.forename: T
authors.initials: T
authors.lastname: Bisseling
mesh_terms: D001483:Base Sequence; D018744:DNA, Plant / Q000235:genetics; D007887:Fabaceae / Q000187:drug effects / Q000235:genetics* / Q000382:microbiology*; D015870:Gene Expression / Q000187:drug effects; D017343:Genes, Plant / Q000187:drug effects; D005819:Genetic Markers; D007874:Leghemoglobin / Q000235:genetics*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D009566:Nitrates / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics; D010946:Plants, Medicinal; D016961:Rhizobium leguminosarum / Q000502:physiology
chemical_list: D018744:DNA, Plant; D005819:Genetic Markers; D007874:Leghemoglobin; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D009566:Nitrates; C092736:Nod factor, Rhizobium leguminosarum; D010940:Plant Proteins; C045625:nodulin; C006568:ammonium nitrate