Granule‐bound starch synthase (GBSS) diversity of ancient wheat and related species

Abstract

Granule-bound starch synthase of ancient wheat and related species was examined by sodium dodecyl sulphate polyacrylamide gel. A total of 13 different alleles were revealed in a collection of three accessions of diploid wheat, six accessions of tetraploid wheat, 49 accessions of spelt wheat, nine accessions of Sitopsis and two accessions of Aegilops tauschii. A new allele named Wx-A1a' appeared in four spelt wheat accessions. The tetraploid wheat accessions evaluated did not show any polymorphism; nevertheless the tetraploid accessions of Sitopsis section revealed three novel alleles. The novel allele Wx-D(dn)1g was found in two accessions of A. ventricosa and the Wx-D(dcm)1h and Wx-D(dcm)1i in two accessions of A. crassa. A novel allele named Wx-A(u)1g was found in Triticum urartu, which is different from the also new Wx-A(m)1h allele of T. monococcum. The diploid-related species accessions revealed two novel alleles named Wx-B(sl)1h and Wx-B(s)1g found, respectively, in A. longissima and A. speltoides. The amylose content was measured for the different alleles found in all evaluated species and no significant effects of the allele composition on the amylose content were detected

Molecular characterization of a new waxy allele with partial expression in spelt wheat

“…One similar result was indicated by Caballero et al (2008) that provisionally named the partially null allele found as Wx-A1a 0 . Although following this discovery, this new allele was designated Wx-A1g by McIntosh et al (2009).…”

Wheat waxy proteins: polymorphism, molecular characterization and effects on starch properties

“…However, the molecular reason for this reduced expression has not been evaluated. A similar process was observed by Caballero et al (2008) for the Wx-A1 protein in some Spanish spelt accessions. The molecular characterisation of this allele (Wx-A1g) showed the presence of a TLE inside the fourth intron that modified the normal splicing of the mRNA (Guzmán et al 2012a).…”

“…Thell. ), Caballero et al (2008) also found a novel variant for Wx-A1 with reduced expression that was named Wx-A1a′ and later catalogued by McIntosh et al (2013) as Wx-A1g.…”

“…Later, Rodríguez-Quijano et al (2004) did not show intraspecific polymorphism for waxy proteins in einkorn and Aegilops, but their mobility differed from their homologs in common wheat, Wx-A1a and Wx-B1a. Caballero et al (2008) also identified and catalogued the waxy protein variants found in relatives of wheat (einkorn and Aegilops), although their nomenclature has not been used in further studies, probably because of the absence of molecular data that would better illustrate their results and allow good comparisons with other alleles. Guzmán et al (2009) found one einkorn accession with a waxy protein, named Wx-A m 1a′, with slightly less mobility than the common one of this species, described previously by Rodriguez-Quijano et al (2004).…”

“…In spelt, Caballero et al (2008) detected a Wx-A1 allele with reduced expression that was characterised by Guzmán et al (2012a). This allele (catalogued as Wx-A1g) presented a 160-bp insertion (TLE) in the fourth intron that could affect the maturation of primary transcripts due to aberrant splicing, which probably reduced the final amount of the Wx-A1 protein in the grain.…”