Sequencing evidence for differentiation of Gaeumannomyces graminis var. tritici isolates originated from wheat and rye

Abstract

Gaeumannomyces graminis var. tritici (Ggt), a homothallic fungus of the Ascomycota, causes take-all disease-the most economically important root disease of wheat in all cropping areas around the world. Severe infections impair plant nutrition and reduce yield dramatically. Resistance to Ggt has not been found in the Triticum germplasm so far. It was shown that a significant genetic variation in fungus populations causes major problems for stability of host-plant disease resistance. In an attempt to understand the variation among isolates of G. graminis in depth, descriptive data are required in addition to morphological and physiological charactersation. Many molecular tools can be applied to assess intravarietal differentiation of Ggt. In the present study, the internal transcribed spacers of ribosomal DNA are shown to be sufficiently variable to distinguish Ggt isolates originated from different host crop species. The region analysed yielded fragments ranging in length from 502 to 503 nt and a total of five variable sites throughout the exons across all isolates was revealed. The hierarchical grouping revealed twomajor clades of isolates named W (originating from winter wheat) and R (originating from winter rye). © 2012 Springer-Verlag and the University of Milan.