Abstract
Abstract Hydrophobic mutants of the Bradyrhizohium japonicum strain 138NR were obtained by transposon Tn5 mutagenesis followed by replica-plating on polystyrene plates. Fifteen mutants were isolated at a frequency of 106. Gel-filtration analysis of the exopolysaccharides revealed that the hydrophobic mutants produced a significantly smaller amount of low-molecular-weight polysaccharides than the parent. Four of the isolated mutants formed a larger number of nodules on soybean (Glycine max L. Merr. cv. Tamahomare) than the parent, two were superior in symbiotic nitrogen fixation, and two were symbiotically defective on soybean. Competitive nodulation abilities of the mutants were examined by inoculating them to soybean with B. japonicum strain 123ET as a competitor and determining the nodule occupancy based on the antibiotic resistance. All the mutants tested except for the symbiotically defective ones were superior in their competitive nodulation ability to the parent strain. When inoculated 24 h before t...
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call