title: Secretion of the Rhizobium leguminosarum nodulation protein NodO by haemolysin-type systems.
abstract: The Rhizobium leguminosarum biovar viciae nodulation protein NodO is partially homologous to haemolysin of Escherichia coli and, like haemolysin, is secreted into the growth medium. The NodO protein can be secreted by a strain of E. coli carrying the cloned nodO gene plus the haemolysin secretion genes hlyBD, in a process that also requires the outer membrane protein encoded by tolC. The related protease secretion genes, prtDEF, from Erwinia chrysanthemi also enable E. coli to secrete NodO. The Rhizobium genes encoding the proteins required for NodO secretion are unlinked to nodO and are unlike other nod genes, since they do not require flavonoids or NodO for their expression. Although proteins similar to NodO were not found in rhizobia other than R. leguminosarum bv. viciae, several rhizobia and an Agrobacterium strain containing the cloned nodO gene were found to have the ability to secrete NodO. These observations indicate that a wide range of the Rhizobiaceae have a protein secretion mechanism analogous to that which secretes haemolysin and related toxins and proteases in the ENterobacteriaceae.
authors.affiliation: John Innes Institute, John Innes Centre, Norwich, UK.
authors.forename: A K
authors.initials: AK
authors.lastname: Scheu
authors.forename: A
authors.initials: A
authors.lastname: Economou
authors.forename: G F
authors.initials: GF
authors.lastname: Hong
authors.forename: S
authors.initials: S
authors.lastname: Ghelani
authors.forename: A W
authors.initials: AW
authors.lastname: Johnston
authors.forename: J A
authors.initials: JA
authors.lastname: Downie
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002135:Calcium-Binding Proteins; D003001:Cloning, Molecular; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D006460:Hemolysin Proteins / Q000378:metabolism; D012230:Rhizobiaceae / Q000235:genetics / Q000378:metabolism; D016961:Rhizobium leguminosarum / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002135:Calcium-Binding Proteins; D003470:Culture Media; D006460:Hemolysin Proteins; C062095:NodO protein, Rhizobium leguminosarum