title: Symbiotic mutants of Rhizobium meliloti that uncouple plant from bacterial differentiation.
abstract: Spontaneous mutants at a new symbiotic locus in Rhizobium meliloti SU47 are resistant to several phages and are conditionally insensitive to a monoclonal antibody to the bacterial surface, apparently because they are deficient in a wild-type exopolysaccharide. On alfalfa, the mutants do not curl root hairs, but penetrate the epidermis directly, forming nodules that contain no visible infection threads or "bacteroids," have a few bacteria in superficial intercellular spaces only and not within the nodule cells, and fail to fix nitrogen (Fix-). Evidently, infection threads are not essential for cell proliferation and nodule formation, which are here induced by a bacterial signal at a distance and uncoupled from the bacterial differentiation that normally goes on as well.
authors.forename: T M
authors.initials: TM
authors.lastname: Finan
authors.forename: A M
authors.initials: AM
authors.lastname: Hirsch
authors.forename: J A
authors.initials: JA
authors.lastname: Leigh
authors.forename: E
authors.initials: E
authors.lastname: Johansen
authors.forename: G A
authors.initials: GA
authors.lastname: Kuldau
authors.forename: S
authors.initials: S
authors.lastname: Deegan
authors.forename: G C
authors.initials: GC
authors.lastname: Walker
authors.forename: E R
authors.initials: ER
authors.lastname: Signer
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D001435:Bacteriophages / Q000502:physiology; D004251:DNA Transposable Elements; D005798:Genes, Bacterial; D000455:Medicago sativa; D009154:Mutation; D009584:Nitrogen / Q000378:metabolism; D010944:Plants / Q000378:metabolism / Q000382:microbiology*; D011135:Polysaccharides, Bacterial / Q000235:genetics; D012231:Rhizobium / Q000235:genetics* / Q000276:immunology; D013559:Symbiosis
chemical_list: D000911:Antibodies, Monoclonal; D004251:DNA Transposable Elements; D011135:Polysaccharides, Bacterial; D009584:Nitrogen