Symbiotic mutants of rhizobium meliloti that uncouple plant from bacterial differentiation

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

Research output: Contribution to journalArticlepeer-review

164 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)869-877
Number of pages9
Issue number4
StatePublished - Apr 1985

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)

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