title: Requirement of succinate dehydrogenase activity for symbiotic bacteroid differentiation of Rhizobium meliloti in alfalfa nodules.
abstract: Transmission electron microscopy was used to study the cellular morphologies of a wild-type Rhizobium meliloti strain (L5-30), a nitrogen fixation-ineffective (Fix-) succinate dehydrogenase mutant (Sdh-) strain, and a Fix+ Sdh+ revertant strain within alfalfa nodules and after free-living growth in a minimal medium containing 27 mM mannitol plus 20 mM succinate. The results showed a requirement of succinate dehydrogenase activity for symbiotic differentiation and maintenance of R. meliloti bacteroids within alfalfa nodules and for succinate-induced cellular pleomorphism in free-living cultures. Also, the Sdh- strain had a 3.5-fold lower rate of oxygen consumption in the defined medium than did the wild type.
authors: Department of Microbiology, Michigan State University, East Lansing 48824.
authors: A E
authors: AE
authors: Gardiol
authors: G L
authors: GL
authors: Truchet
authors: F B
authors: FB
authors: Dazzo
mesh_terms: D000455:Medicago sativa / Q000382:microbiology; D008854:Microscopy, Electron; D009586:Nitrogen Fixation; D010101:Oxygen Consumption; D012231:Rhizobium / Q000201:enzymology* / Q000648:ultrastructure; D013385:Succinate Dehydrogenase / Q000378:metabolism*; D013559:Symbiosis
chemical_list: D013385:Succinate Dehydrogenase