Molecular Analysis of the Wheat Blast Population in Brazil with a Homolog of Retrotransposon MGR583.

Abstract

We have identified a family of dispersed repetitive DNA sequences in the genome of a Magnaporthe grisea isolate from finger millet (Eleusine coracana). Southern blot analyses showed that this element is present in a moderate copy number (30-40 copies) in the genome of blast isolates from wheat (Triticum aestivum). DNA sequence data suggested that this element contains a region highly homologous to the reverse transcriptase domain of MGR583, a poly A-type retrotransposon. Using the reverse transcriptase domain of this element as a molecular probe, the genetic structure of the wheat blast population was examined. DNA fingerprinting analyses revealed that the wheat-infecting isolates constitute a separate, single lineage of their own, suggesting that they are derived from a single origin.