Genetic variability of Glu-A3 locus in argentinean hexaploid wheat (Triticum aestivum L.) cultivars

MANCINI M.; VANZETTI L.; HELGUERA M.

Rosario. Argentina

Congreso; 1º Conferencia Latinoamericana ICC; 2007

Wheat seed storage proteins are composed by two major fractions termed gliadins and glutenins. These proteins play a key role in the determination of dough and bread-making quality. Glutenins are polymeric proteins whose subunits are classified into two groups, high-molecular-weight (HMWGs, 80-120 kDa) and low molecular weight (LMWGs 30-50 kDa) subunits. The majority of LMWGs are controlled by the Glu-A3, Glu-B3, and Glu-D3 genes, on the short arms of chromosome 1A, 1B, and 1D, respectively (Payne 1987). LMWGs are not as well characterized as HMWGs because of the complexity of band paterns observed by SDS-PAGE. Diverse molecular markers were development to facilitate the genetic variability characterization of the LMWGs genes (Devos et al. 1995 and Zhang et al.2004). The goal of this study was to characterize the genetic variability of the Glu-A3 locus in Argentinean common hexaploid wheat cultivars using allele-specific and microsatellite molecular markers. Glu-A3 specific markers detected 8 different alleles with relative frequencies of Glu-A3a f=3%, Glu-A3b f=7%, Glu-A3c f=32%, Glu-A3d f=15%, Glu-A3e f=11%, Glu-A3f f=28%, Glu-A3g f=3% and Glu-A3n f=1%. The Glu-A3n allele (not described in Zhang et al. 2004) did not show amplification with any allele specific markers, and it was observed in the cultivar Biointa 3003 which posses the 1AS/1RL rye translocation. Xpsp2999 microsatellite marker analysis showed 9 different alleles with relative frequencies as it follows: 144/130 pb f=28%, 153 pb f=32%, 144 pb f=29%, 155/140 pb f=3%, 155/145 pb f=1%, 150/135 f=1%, 150bp f=1%, 150/145 pb f=4% and 115 pb f=1%.  On the basis of these results wheat cultivars were grouped in different arrays depending on the marker. Interestingly, the use of combined data from both markers was able to discriminate 14 different alleles with relative frequencies between 1 and 28%. These results suggest that the two types of markers used in this study detect different sources of genetic variability linked or into the Glu-A3 locus. These markers seem to be a promising tool to further dissect the effect of single LMWGs alleles in bread quality parameters.