Analysis of x- and y-type high molecular weight glutenin subunit genes associated to the A and G-genomes in Triticum Timopheevi.

T. timopheevii is a tetraploid species (AtAtGG) morphologically similar to T. durum (AABB) but with distinctive biochemical, genetical traits and karyotype structure, considered as a valuable donor of peculiar traits and used in wheat breeding. Previous results obtained by electrophoresis (SDS-PAGE) and chromatographic (RP-HPLC) analyses of high molecular weight glutenin subunits (HMW-GS) present in several accessions of T. timopheevii ssp. timopheevii (cultivated) and ssp. araraticum (wild), permitted to associate different type of subunits to the A and G genome. Genes corresponding to these subunits were amplified by polymerase chain reaction (PCR). DNA fragments corresponding to x- and y-type genes associated to the A genome were detected in all accessions including those without expressed x- and y-type subunits. The absence in the y-type genes associated to A genome of the particular 8-kb transposon-like insertion, usually present in unexpressed y­type genes at Glu-A1 locus in the bread wheat cultivar Chinese Spring, has also been shown.