Monitoring changing virulence patterns of Uromyces appendiculatus in the resistant pinto bean cultivar Olathe by rep-PCR

Corresponding molecular markers associated with avirulence or virulence genes in the bean rust pathogen are currently unknown, although host resistance genes have been linked to molecular markers in bean. The changing virulence patterns in pathotypes of Uromyces appendiculatus collected over a 14-year period after the release of the Ur-6 resistance gene on the USA high plains were therefore analyzed using rep-PCR molecular markers. Isolates from two neighbouring pathotype groups from Colorado and Nebraska were screened using the rep-PCR primer Box-AIR. The PCR fragment Box ₄₇₅ was cloned and sequenced and a specific primer set ATA-2 was designed. This primer yielded 10 polymorphic products which allowed separation of these isolates into two distinct groups and will be useful for future analysis of the population genetics of this organism.