title: Genotypic Diversity among Strains of Bradyrhizobium japonicum Belonging to Serogroup 110.
abstract: Thirty-three strains of Bradyrhizobium japonicum within serogroup 110 were examined for genotypic diversity by using DNA-DNA hybridization analyses. The analysis of the DNA from 15 hydrogen-uptake-negative strains with the bradyrhizobial uptake hydrogenase probe pHU52 showed variation in degree of homology and restriction fragment length polymorphism of EcoRI-restricted DNA. Clustering analysis of the 33 strains on the basis of DNA-DNA hybridization analysis with four restriction enzymes and with the bradyrhizobial nodulation locus, pRJUT10, as probe indicated the existence of four groups of strains, which were less than 70% similar. Restriction digestion of genomic DNA with BamHI and DNA-DNA hybridization with pRJUT10 permitted classification of each of the strains according to a specific fingerprint pattern.
authors.affiliation: Soybean and Alfalfa Research Laboratory, Agricultural Research Service, HH-19, Building 011, BARC-West, U.S. Department of Agriculture, Beltsville, Maryland 20705; Department of Agronomy, University of Maryland, College Park, Maryland 20742 ; and Department of Botany, Zagazig University, Cairo, Egypt.
authors.forename: P
authors.initials: P
authors.lastname: van Berkum
authors.forename: S I
authors.initials: SI
authors.lastname: Kotob
authors.forename: H A
authors.initials: HA
authors.lastname: Basit
authors.forename: S
authors.initials: S
authors.lastname: Salem
authors.forename: E M
authors.initials: EM
authors.lastname: Gewaily
authors.forename: J S
authors.initials: JS
authors.lastname: Angle