Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/15/1997
Publication Date: N/A
Interpretive Summary: Wheat quality is strongly affected by not only the amount of protein in the flour or, in the case of pasta, in the semolina, but also by the kinds of proteins present. Considerable information on the kinds of proteins present in wheat seeds is available. However, knowledge of the locations and relationships of the genes that control the production of the various kinds of proteins is lacking. The map locations of protein genes on the chromosomes of various types of wheat were determined and compared using several populations of plants segregating for these genes. The results clarify the comparative map location of the various protein genes. This new knowledge will assist the plant breeder in his efforts to produce wheat varieties with superior protein quality.
Technical Abstract: Linkages between high and low Mw glutenin, gliadin and triticin loci in diploid, tetraploid and hexaploid wheats were studied using DNA clones. In tetraploid and hexaploid wheat, DNA fragments hybridizing only with a low Mw glutenin clone were detected at two different loci on chromosome 1B. Most DNA fragments were mapped at the XGlu-B3 locus on the distal part of the map of chromosome arm 1BS. However, other DNA fragments were completely linked to XGli-B3 locus in the middle of the map of the same chromosome arm. This suggests that this low Mw glutenin locus, designated XGlu-B2, is either closely linked to toe gliadin locus XGli-B3 or is part of a compounded locus that contain both gliadin and low Mw glutenin genes. The restriction fragments mapped at this locus were shown to cosegregate with B subunits of low Mw glutenins in SDS-PAGE in tetraploid wheat indicating that XGlu-B2 is an active low Mw clone. No glutenin protein was found to cosegregate with this new locus. A triticin locus, XTri-B1, was mapped on chromosome 1B completely linked to the centromere. Failure to detect triticin proteins cosegregating with these DNA fragments suggests that the XTri-B1 locus is not active. Recombination between XGli-A1 and XGli-A3 (19.6 cM) in tetraploid wheat was within the range observed in chromosome 1A in diploid (15.1 to 20.7 cM) and hexaploid wheat species (13.0 to 26.6 cM). No evidence was found for the existence of Gli-A4. This locus is presumably synonymous with Gli-A3. Recombination was observed within the multigene gliadin family mapped at XGli-A1 (1.2 cM). Though these closely linked loci may correspond to previously named Gli-A1 and Gli-A5 loci they were temporarily designated XGli-A1.1 and XGli-A1.2 until orthology with Gli-A1 and Gli-A5 is established.