Effective method for the isolation of non-nodulating mutants of<i>Rhizobium trifolii</i>

Abstract

SUMMARY Non-nodulating mutants of Rhizobium trifolii were found in cultures incubated at 35 °C for 7 days. From among ten strains incubated at the elevated temperature six became non-nodulating. The frequency of Nod − mutants in R. trifolii cultures varied from 1 to 75% depending on the strain tested. It is suggested that gene(s) controlling nodulation are located on a large plasmid.