Electrophoretic Patterns of Soluble Proteins and Isoenzymes of Gaeumannomyces graminis

Abstract

The wheat and oat take-all fungi show a close serological relationship with Gaeumannomyces graminis var. graminis isolated from kikuyu grass, supporting the conclusions of Walker, who recognized the three fungal groups as varieties of G. graminis based on morphological characters. Three techniques for studying proteins (disc and gradient gel electrophoresis and isoelectric focusing) were assessed as possible aids in identifying and classifying isolates of G. graminis. Protein patterns were affected by the age of the mycelium and the composition of the growth medium used. Patterns prepared by disc electrophoresis were helpful for identifying isolates of G. graminis, but not for separating the varieties. Gradient gel electrophoresis patterns were sufficient for distin- guishing the kikuyu grass isolate from take-all fungi isolated from wheat or oats, but the differences between the patterns of the wheat and oat take-all fungi were too slight to aid in identifying these varieties. Esterase and peroxidase isoenzyme patterns of the isolates from the three varieties were too variable to assist in identifying isolates of G. graminis at either the species or the variety level. Isoelectric focusing patterns of the proteins for each variety were useful for distinguishing the kikuyu grass isolate from the wheat and oat take-all fungi. The protein patterns illustrate a closer relationship between the wheat and oat take-all fungi than either has with the variety of G. graminis from kikuyu grass. None of the methods gave a convenient means of separating the wheat and oat take-all fungi.