title: Host-Pathogen Interactions : XX. BIOLOGICAL VARIATION IN THE PROTECTION OF SOYBEANS FROM INFECTION BY PHYTOPHTHORA MEGASPERMA F. SP. GLYCINEA.
abstract: Phytophthora megasperma f.sp. glycinea, which causes soybean (Glycine max) root and stem rot, exists as several races which differ in their ability to infect a range of soybean cultivars. A glycoprotein-rich fraction (Fraction I) isolated from fungal culture fluid protects soybean seedlings from infection with compatible races. In an early study (13), seedlings were protected only by Fraction I purified from incompatible races. In 1979, seedlings were better protected by Fraction I isolated from incompatible races than by Fraction I isolated from compatible races. In 1980, seedlings were protected equally well by Fraction I from incompatible and compatible races. Materials similar in composition to Fraction I did not protect seedlings from infection. No cause could be identified for the apparent change, during the 3-year period, in the race specificity of the protection assay. Variability in the bioassay prohibited further purification or characterization of Fraction I components that protect seedlings from infection.
authors: Department of Chemistry, University of Colorado, Boulder, Colorado 80309.
authors: A E
authors: AE
authors: Desjardins
authors: L M
authors: LM
authors: Ross
authors: M W
authors: MW
authors: Spellman
authors: A G
authors: AG
authors: Darvill
authors: P
authors: P
authors: Albersheim