Bacterial and Bacteroid Properties of Mutants of Rhizobium Trifolii Strain T1 Uncoupled in Oxidative Phosphorylation

Abstract

Using the neomycin-resistance selection technique, mutants uncoupled in oxidative phosphorylation were isolated in R. tri/olii strain Tl. These mutants had no detectable ATP-synthesizing activity and between 8 and 20% of the ATP-degrading activity of their parent strain in the bacterial form. The mutants formed nitrogen-fixing nodules on red, white, and subterranean clovers, and bacteroids isolated from white clover nodules had a high level of ATPase activity of about 70% of that found in bacteroids of their parental strain. The possibility that a new ATPase complex is synthesized when the bacteria differentiate to form bacteroids within the nodule is discussed.