Evidence of asexual recombination in Rhynchosporium secalis

Abstract

Three single‐spore isolates of Rhynchosporium secalis that differed in their α‐esterase and β‐glucosidase isozyme patterns were inoculated as two mixtures, each of two isolates, on to seedlings of the susceptible barley cultivar Maris Mink. Approximately 100 single‐spore isolates were taken from mature lesions produced by each mixture. These were subjected to polyacrylamide gel electrophoresis and the gels were stained for α‐esterase and β‐glucosidase. Parental types only were produced by one of the isolate mixtures. However, one of the 10 lesions examined for the second mixture produced nine isolates with a novel combination of isozymes, indicating that some form of asexual recombination had occurred. The use of isozymes as a natural marker system for the detection in vivo of asexual recombination in pathogenic fungi is discussed.