Abstract
The SDS-PAGE pattern of reduced and alkylated glutenins from the bread wheat cultivar Prinqual presents a subunit (named d4) in the mobility zone of the omega -gliadins that only appears under reduced conditions. This subunit was isolated and characterised at the biochemical and genetic levels. Subunit d4 was shown to form disulphide aggregates with glutenins and had an acidic pI. These characteristics correspond to those of the D glutenin subunits. The N-terminal amino acid sequence of subunit d4 was coincident with the SRL sequence type characteristic of omega -gliadins encoded by genes on the 1B chromosome, and confirms the similarity between D glutenin subunits and omega -gliadins. The genetic study of subunit d4 was performed in the F2 progeny from the 'Prinqual' x 'Ablaca' cross, based on four prolamin loci: Glu-B1, Glu-B3, Gli-B1, and Gli-B5. The recombinants found between Glu-B3 and Gli-B1 demonstrated that subunit d4 was encoded at the Glu-B3 locus, and reinforces the hypothesis of the duplication of prolamin gene clusters in wheat. A preliminary study of the effect of subunit d4 on gluten strength showed that lines with the Glu-B3 allele from 'Prinqual', which includes subunit d4, had a significantly higher sedimentation volume than those with the allele from 'Ablaca'.Key words: wheat gluten proteins, D glutenin subunits, amino acid sequence, linkage mapping, complex loci duplication.
Published Version
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