Interactions Among WxGenes and Effects of a Mutated Wx-D1eAllele on Starch Properties in Wheat

The waxy mutant wheat Tanikei A6599-4 contains little amylose and exhibits a stable hot paste viscosity. It has null alleles at the Wx-A1and Wx-B1loci and a mutated allele at the Wx-D1locus (Wx-D1e). From the cross-combination of Kanto 123 (normal amylose line) and Tanikei A6599-4, 51 DH (doubled haploid) lines were produced and their genotypes were determined by SDS-PAGE and a derived cleaved amplified polymorphic sequence (dCAPS) analysis. Eight genotypes were obtained at the expected ratio. Using a Rapid Visco Analyser (RVA), all the lines with the same genotype as Tanikei A6599-4 showed a stable hot paste viscosity. The other lines did not show a stable hot paste viscosity regardless of the presence of the Wx-D1eallele. When two genotypes with the same Wx-A1and Wx-B1alleles were compared, the one with Wx-D1econtained less amylose and exhibited a lower final viscosity and a lower setback with RVA. Although the Wx-D1eallele produces an almost inactive Wx protein, these findings suggest that this allele contributes at some level to starch synthesis.