Rhizobium strains exhibiting enhanced capacities for fixing gaseous nitrogen

摘要

The present invention relates to a Rhizobium strain genetically engineered so as to enhance its ability to fix nitrogen symbiotically, characterised in that it is chosen from: a) the fixK mutants affected only in the repression of the nif and fix genes and hardly or not at all in the activation of the fix genes; b) the mutants rendered totally or partially insensitive to the repressor effect of fixK.