Significant effects in bread making quality associated with the gene cluster GLU-D3/GLI-D1 from the common hard wheat cultivar PROINTA GUAZÚ

DEMICHELIS M.; VANZETTI L.; PFLUGER L.; BAINOTTI C.; MIR L.; CUNIBERTI M.; HELGUERA M.

San Petesburgo. Rusia

Conferencia; 8 International Wheat Conference; 2010

Seed storage proteins (gliadins and glutenins) play a key role in the determination of dough and bread making quality in common wheat (Triticum aestivum L.). This is due to the interaction between high and low molecular weight glutenins and gliadins, via complex inter- and intra- molecular bondings. Different roles can be attributed to the glutenins. The high molecular weight glutenins (HMWGs) form the polypeptide network responsible for the visco-elastic properties of dough and the low molecular weight glutenin subunits (LMWGs) function as chain extenders or terminators according to the number of cysteine residues available for disulfide bonding. LMWGs functioning as extenders are thought to increase the polymer size and confer dough strength and, in opposition, LMWGs functioning as chain terminators will decrease polymer size and dough strength. In contrast with HMWGs subunits, resolution of LMWGs and scoring of alleles by protein or molecular analysis is difficult due to the large number of expressed subunits and coding genes. For these reasons the role of individual LMWGs in the determination of wheat quality is less clear. A similar situation can be considered in the case of gliadins, complex protein patterns and complex genetics (multigene families and a close association between Gli-1 and Glu-3 loci) complicates the determination of gliadins role in dough formation.   In this work we studied the effect of clusters Glu-A3/Gli-A1 and Glu-D3/Gli-D1 in bread making quality parameters using 20 F4-6 families generated from the cross ProINTA Guazú x ProINTA Oasis, both cultivars carrying identical HMWGs subunits composition and presence of 1BL/1RS wheat-rye translocation, but differing in Glu-A3 and Glu-D3 LMWGs subunits and Gli-A1 and Gli-D1 gliadins patterns. Seeds from 136 F2 plants were scored by SDS-PAGE and A-PAGE and 20 families divided in four groups carrying homozygous parental or recombinant Glu-A3/Gli-A1 and Glu-D3/Gli-D1 gene clusters were selected. No recombination events in-between gene clusters were observed. Partial seed from F4, F5 and F6 selected families was used to determine bread making quality parameters protein content (PC), Zeleny sedimentation test (ZT) and mixograph developmental time (MDT) using standard protocols. Successive ANOVAs showed, in the case of PC, only a highly significant effect of year (P<0.0001) and no significant effects of Glu-A3/Gli-A1, Glu-D3/Gli-D1 gene clusters or interactions. ZT and MDT variation was significantly affected by year (P<0.0001) and Glu-D3/Gli-D1 gene cluster (P<0.0001), and no significant effect of Glu-A3/Gli-A1 cluster was observed (P=0.9 and P=0.2, respectively). In Glu-D3/Gli-D1 gene cluster, LSD analysis showed consistently a significant and positive effect of ProINTA Guazú vs. ProINTA Oasis locus in quality parameters ZT (48.17s vs. 43.13s) and MDT (5.6min vs. 4.06min). In MDT a significant interaction effect Glu-D3/Gli-D1 x year was also observed (P<0.0001) however independently of the year, MDT values from families carrying ProINTA Guazú Glu-D3/Gli-D1 cluster were consistently higher than MDT values from ProINTA Oasis. Further efforts are being carried out in order to precisely determine if observed differences in dough strength are caused by a favorable effect of ProINTA Guazú proteins or by a detrimental effect of ProINTA Oasis'.