Nod factor structures, responses, and perception during initiation of nodule development.
The onset of nodule development, the result of rhizobia-legume symbioses, is determined by the exchange of chemical compounds between microsymbiont and leguminous host plant. Lipo-chitooligosaccharidic nodulation (Nod) factors, secreted by rhizobia, belong to these signal molecules. Nod factors consist of an acylated chitin oligomeric backbone with various substitutions at the (non)reducing-terminal and/or nonterminal residues. They induce the formation and deformation of root hairs, intra- and extracellular alkalinization, membrane potential depolarization, changes in ion fluxes, early nodulin gene expression, and formation of nodule primordia. Nod factors play a key role during nodule initiation and act at nano- to picomolar concentrations. A correct chemical structure is required for induction of a particular plant response, suggesting that Nod factor-receptor interaction(s) precede(s) a Nod factor-induced signal transduction cascade. Current data on Nod factor structures and Nod factor-induced responses are highlighted as well as recent advances in the characterization of proteins, possibly involved in recognition of Nod factors by the host plant.
D'Haeze
Wim
W
Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology, Ghent University, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
Holsters
Marcelle
M
D000818:Animals; D006790:Host-Parasite Interactions; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D008958:Models, Molecular; D009586:Nitrogen Fixation; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism / Q000382:microbiology; D012231:Rhizobium / Q000737:chemistry* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013559:Symbiosis
D008070:Lipopolysaccharides