Molecular Genetic Classification of Fusarium oxysporum f. Sp. Vasinfectum

An understanding of the pathogenic diversity present in a population of a given disease organism is necessary for the effective development and deployment of host-plant resistance.  The need for rapid and accurate diagnostic tools for identifying races or genotypes of the Fusarium wilt pathogen, Fusarium oxysporum f. sp. vasinfectum, has increased since it was shown that populations in the United States are no longer limited to races 1 and 2.  Multi-gene phylogenies have revealed the presence of races 3, 4, and 8, as well as four novel genotypes in the U.S.  A DNA-based macroarray using the translation elongation factor gene was developed to rapidly and accurately identify races 1, 3, 4, 8, and Australian biotypes.  A broad understanding of the genetic diversity of this fungus is a first step toward characterizing its pathogenic diversity.