Benedetta Margiotta

A bread wheat line (N11) and a disomic 2D(2R) substitution triticale line were crossed and backrossed four times. At each step electrophoretic selection for the seeds that possessed, simultaneously, the complete set of high molecular weight glutenin subunits of N11 and the two high molecular weight secalins of rye, present in the 2D(2R) line, was carried out. Molecular cytogenetic analyses of the BC₄F₈ generation revealed that the selection carried out produced a disomic addition line (2n = 44). The pair of additional chromosomes consisted of the long arm of chromosome 1R (1RL) from rye fused with the satellite body of the wheat chromosome 6B. Rheological analyses revealed that the dough obtained by the new addition line had higher quality characteristics when compared with the two parents. The role of the two additional high molecular weight secalins, present in the disomic addition line, in influencing improved dough characteristics is discussed.

Three Apulian (SE Italy) coastal sites, Torre Canne to Torre San Leonardo (T), Punta della Contessa Salt Pans (S) and the La Vela Swamp (P), characterised by sandy shores and salt marshes recognised as wetland environments belonging to the Natura 2000 network, were selected as study areas in order to survey the vegetation zonation, plant communities, ecological context and genetic diversity of Thinopyrum elongatum population within humid habitats. Analysis of vegetation, plant communities and soil samplings were carried out to investigate the ecological context of 24 populations collected of this halophile wheatgrass, along with biochemical characterization (A-PAGE, SDS-PAGE, and IEFxSDS-PAGE) of seed storage proteins, used to assess the genetic diversity intra- and inter-populations and genotype frequencies. Thinopyrum elongatum populations showed a significative presence in the halophile shrub plant communities of salt marshes, especially those characterised by Limbarda crithmoides and Artemisia caerulescens. The differences of the protein patterns, suggest the presence in the T area of a higher genetic variability and a greater resistance to the numerous factors of human pressure. The results have been discussed hypothesizing that this multidisciplinary approach could be considered a model to evaluate in the future the same environments or other similar ones, subjected to anthropogenic pressures and environmental changes.

Among wheat gluten proteins, the α-type gliadins are the major responsible for celiac disease, an autoimmune disorder that affects about 1% of the world population. In fact, these proteins contain several toxic and immunogenic epitopes that trigger the onset of the disease. The α-type gliadins are a multigene family, encoded by genes located at the complex Gli-2 loci. Here, three bread wheat deletion lines (Gli-A2, Gli-D2 and Gli-A2/Gli-D2) at the Gli-2 loci were generated by the introgression in the bread wheat cultivar Pegaso of natural mutations, detected in different bread wheat cultivars. The molecular characterization of these lines allowed the isolation of 49 unique expressed genes coding α-type gliadins, that were assigned to each of the three Gli-2 loci. The number and the amount of α-type gliadin transcripts were drastically reduced in the deletion lines. In particular, the line Gli-A2/Gli-D2 contained only 12 active α-type gliadin genes (−75.6% respect to the cv. Pegaso) and a minor level of transcripts (−80% compared to cv. Pegaso). Compensatory pleiotropic effects were observed in the two other classes of gliadins (ω- and γ-gliadins) either at gene expression or protein levels. Although the comparative analysis of the deduced amino acid sequences highlighted the typical structural features of α-type gliadin proteins, substantial differences were displayed among the 49 proteins for the presence of toxic and immunogenic epitopes. The deletion line Gli-A2/Gli-D2 did not contain the 33-mer peptide, one of the major epitopes triggering the celiac disease, representing an interesting material to develop less “toxic” wheat varieties.