Symbiotic mutants of rhizobium meliloti that uncouple plant from bacterial differentiation Academic Article uri icon

  • Overview
  • Research
  • Identity
  • Additional Document Info
  • View All


  • 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.


  • Finan, Turlough Mary
  • Hirsch, Ann M
  • Leigh, John A
  • Johansen, Eric
  • Kuldau, Gretchen A
  • Deegan, Sarah
  • Walker, Graham C
  • Signer, Ethan R

publication date

  • April 1985

published in