Identification of molecular markers for the Pc39 gene conferring resistance to crown rust in oat

The aim of this study was the identification of molecular markers for the Pc39 gene in cultivated oat (Avena sativa L.). Pc39 is a major race-specific crown rust resistance gene originally found in an Israeli accession of the wild hexaploid Avena sterilis. The effectiveness of this gene in Europe has decreased in recent years, but is still relatively high and breeding programs would benefit from the availability of molecular markers to aid in its mapping and deployment. The complexity of the oat genome poses a significant obstacle to genetic research. No oat rust resistance genes have yet been cloned, and even the number of relevant molecular markers is very limited. Here, genotyping of a segregating population derived from a cross ‘Celer’ (Pc39)/STH9210 (susceptible) was conducted using RAPD- and SRAP-PCR-based methods, as well as microarray-based DArT™ and next-generation sequencing DArTseq™ techniques. Markers associated with Pc39 were placed on the hexaploid oat consensus linkage group Mrg11 at 3.7–6.7 cM. Six new PCR-based markers were developed to allow identification of the resistant Pc39 allele. These tightly linked markers will be useful in marker-assisted selection, with the closest, SCAR_3456624, being within 0.37 cM of Pc39. The newly developed markers could find applications in the fine mapping or positional cloning of this gene. Moreover, easy-to-use PCR-based markers linked to Pc39 could facilitate the utilization of this gene in oat breeding programs, especially as a component of crown rust resistance gene pyramids.