title: Exopolysaccharide-Deficient Mutants of Rhizobium fredii HH303 Which Are Symbiotically Effective.
abstract: Nineteen Tn5-induced mutants of Rhizobium fredii HH303 defective in acidic exopolysaccharide synthesis were isolated by screening for lack of Calcofluor fluorescence. They were grouped by complementation analysis by using Rhizobium meliloti cosmids carrying exo genes. All of the 19 mutants were symbiotically effective or partially effective, indicating that the major bacterial acidic exopolysaccharide of this strain of R. fredii may not be required for symbiotic development in the soybean.
authors.affiliation: Nitrogen Fixation and Soybean Genetics Laboratory, Agricultural Research Service, U.S. Department of Agriculture, Bldg. 011, HH-19, BARC-W, Beltsville, Maryland 20705.
authors.forename: C H
authors.initials: CH
authors.lastname: Kim
authors.forename: R E
authors.initials: RE
authors.lastname: Tully
authors.forename: D L
authors.initials: DL
authors.lastname: Keister