Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/7/1995
Publication Date: N/A
Interpretive Summary: A group of soilborne-fungi are commonly found in association with small grains and turf grasses. A few of these fungi cause root rot diseases on these plants. It is important to be able to distinguish the disease causing organisms from the benign to recommend control strategies and to breed for resistance to root rotting fungi. However, it is often difficult to tell a disease causing fungi from one that doesn't by simply relying on the appearance of the fungi. In addition, root rotting diseases can be caused by other unrelated organisms. To better differentiate fungi that cause disease from those that do not, we have developed a technique to examine differences in the genetic material, the DNA, of the fungi that may be important for disease induction but which are not manifest in any discernible difference in outward difference in the fungi. This method is highly reliable, much quicker than trying to produce a disease on plants with fungi isolated from diseased plants and requires very small amounts of fungal tissue for the analysis.
Technical Abstract: Randomly applied polymorphic DNAs (RAPD) were used to distinguish among isolates of Gaeumannomyces graminis var. tritici, G. g. var. graminis, G. g. var. avenae, G. incrustans, and G. cylindrosporous. A set of 60 random sequence 10-mer primers were tested, of which 28 produced bands and 15 showed evidence of polymorphism. Four primers produced DNA amplification patterns that could facilitate distinguishing the three varieties of G. graminis, G. incrustans, and G. cylindrosporous. Banding patterns were similar within isolates of G. g. var. tritici, G. g. var. avenae and G. incrustans. Isolates of G. g. var. graminis showed greater variability in banding patterns. UPGMA cluster analysis indicated that the relationship among isolates of G. g. var. tritici and G. g. var. avenae was closer than for isolates of the G. g. var. graminis. The results of this study show that RAPD markers can be used as a method to confirm the identification of Gaeumannomyces species and varieties.