Identification of candidate genes for traits of relevant breeding value transferred from a wild relative to wheat.

Two valuable genes for durum wheat breeding, i.e. Lr19 (leaf-rust resistance) and Yp (yellow endosperm pigmentation), closely linked on the 7AgL chromosome arm of the perennial wheatgrass species Thinopyrum ponticum, have been transferred to the 7AL durum wheat arm by chromosome engineering. Using a ‘NBS profiling’ assay to target Lr19, and a comparative genomics approach for Yp, candidate genes for both traits have been identified

Cytogenetic and molecular characterization of durum wheat chromosome transfers with 1D-associated gluten protein genes and their pyramiding

Gluten quality of bread wheat is known to be mainly associated with high- (HMW-GS) and low-(LMW-GS) molecular weight glutenin subunits encoded by Glu-1 (L arm of group-1 chromosomes) and Glu-3 (S arm of group-1 chromosomes) genes, respectively, with the 1D alleles of such genes having the major impact on bread making properties. Transfer of chromosomal segments containing the Glu-D1 and Gli-D1/Glu-D3 loci was successfully achieved in a number of instances resorting to chromosome engineering. Using this strategy, we isolated two 1A-1D recombinant lines, in which the Gli-D1/Glu-D3 genes and the Glu-D1d allele (HMW-GS "5+10") were separately transferred into the 1AS and 1AL arm, respectively, of recipient durum wheat lines (named PS and PL, respectively). Also, a detailed genetic map of both recombinant chromosome arms was developed. Stable PS + PL double-recombinant lines have been obtained as a result of homologous recombination in the 1A portions shared by the two recombinant chromosomes present in PS x PL hybrids. Preliminary quality tests suggest that the Glu-D3 + Glu-D1d combined presence could determine a slight increase of gluten quality parameters over those associated with Glu-D1d alone

Durum wheat-Thinopyrum ponticum recombinant lines: a tool to finely describe homoeologous 7L arm regions.

As one important result of wheat chromosome engineering, creation of arrays of wheat-alien recombinant chromosomes allows assignment of markers and genes to defined physical locations, hence improving knowledge of structural-functional organization of wheat and alien chromosomal regions and to identify suitable markers for MAS of target genes. Regions involved in our research are the distal portions of wheat 7AL and Thinopyrum ponticum (tall wheatgrass, a wild wheat relative) 7AgL arms, the latter containing several genes of value for wheat improvement