Differences in the biochemical compositions and elicitor activity of extracellular components produced by three races of a fungal plant pathogen, Colletotrichum lindemuthianum.

High molecular weight products from the alpha, beta, and gamma races of Colletotrichum lin- differed in their carbohydrate and protein compositions and in their abilities to elicit symptoms of a hypersensitive response in dark red kidney bean. The neutral sugar composition of the products varied in their proportions of rhamnose, mannose, galactose, and glucose. Polyacrylamide gel electrophoresis showed the protein components to be more numerous in the beta race products than in the alpha or gamma race products. Each protein band co-stained for carbohydrate. Highest elicitor activity was observed in the products from the alpha race, a race avirulent on dark red kidney. The products from the weakly virulent gamma race were about 10-fold less active as elicitors than those of the alpha race. With the beta race, a race highly virulent on dark red kidney, elicitor activity was 100-fold less than that of the alpha race.