Identification of a chromosome-specific probe that maps within the Ph1 deletions in common and durum wheat

The Ph1 (pairing homoeologous) gene is the major factor that determines the diploid-like chromosome behavior of polyploid wheat. This gene, which is located on the long arm of chromosome 5B (5BL), suppresses homoeologous pairing at meiosis while allowing exclusive homologous pairing. In an effort to tag the specific chromosomal region where this gene is located, we have previously microdissected chromosome arm 5BL from bread wheat and produced a plasmid library by random PCR amplification and cloning. In this work we isolated from this library a 5BL-specific probe, WPG90, and mapped it within the interstitial deleted chromosome fragments carrying Phi in common and durum wheat. A PCR assay of Ph1 based on WPG90 was developed that allows an easy identification of homozygous genotypes deficient for this gene.