27 Structure/function relationships of glutenin subunits.

D. LAFIANDRA (1), R. D’Ovidio (1), S. Masci (1), and B. Margiotta (2). (1) Department of Agrobiology and Agrochemistry, University of Tuscia, Viterbo 01100, Italy; (2) Germplasm Institute, C.N.R., Bari 01100, Italy.

Glutenin polymers are formed by two major group of subunits, the high- and the low-molecular weight glutenin subunits, both characterized by the presence of a repetitive domain rich in proline and glutamine, and by cysteine residues mainly located in the non repetitive domains. The number and distribution of cysteine residues can be of extreme importance in determining the size of the glutenin polymers and consequently dough viscoelastic properties, whereas length and regularity of repetitive domains can also contribute, through non-covalent interactions, to affect the same properties. Wheat lines in which glutenin subunits differ in the size of the repetitive domain or the number of cysteine residues have been obtained and used to assess the role of such structural features on wheat technological properties. The complexity of the glutenin polymer is further complicated by the presence of gliadin-like components resulting from gene mutations that change the number of cysteine residues relative to those of monomeric forms. Characterization of these gliadin-like components will be presented and their possible role in affecting flour functional properties will also be discussed.