1997 Volume 63 Issue 3 Pages 155-163
We characterized 24 Japanese isolates of Magnaporthe grisea by DNA fingerprinting and electrophoretic karyotyping. These isolates included seven Japanese differential strains as well as field isolates belonging to various pathogenic races which were collected from all over Japan. We used previously cloned repetitive DNAs, MGR586 and pMG6015, as DNA fingerprinting probes. Bootstrapping analysis revealed that pMG6015 is effective for constructing a robust phylogenetic tree. Five clonal lineages were found in the phylogenetic analysis. All field isolates belonged to one particular clonal lineage JBLA-K04. Electrophoretic karyotypes were polymorphic among isolates in the lineage JBLA-K04, but some similarities of karyotype were observed in the isolates of similar pathogenic race. These results indicate that field isolates of M. grisea were derived from a limited number of clonal lineages and diverged in their host-cultivar specificity, and that variation at the chromosomal level is correlated to race differentiation in the clonal lineage JBLA-K04.
