Consumption of Tritordeum Bread Reduces Immunogenic Gluten Intake without Altering the Gut Microbiota

Tritordeum: Promising Cultivars to Improve Health

Tritordeum is an amphiploides species resulting from the hybridization between durum wheat (T. durum) and wild barley (H. chilense). This new cereal is considered a natural crop as it is obtained by traditional breeding techniques. Given its appreciable organoleptic characteristics, agronomic features, presence of interesting components, and good technological properties, Tritordeum is of promising interest for the development of health-oriented foods. In this study, we evaluated two registered Tritordeum cultivars, Bulel and Aucan. T. durum (Provenzal) was employed as the positive control. The extracted proteins were digested by gastric/pancreatic proteases, and their biological effects on Caco-2 differentiated on transwell inserts were determined. Changes in cell viability, monolayer permeability, organization of F-actin microfilaments, and ER stress triggered by protein-digested samples (DPs) were inspected. Our results showed that exposure to Provenzal-DPs promptly disrupted the tight junction barrier. Conversely, Aucan-DPs did not enhance monolayer permeability, whereas Bulel-DPs exerted only slight effects. Provental-DPs-induced toxicity was also confirmed by changes in cell viability and by the deep reorganization of the enterocyte cytoskeleton. In contrast, Aucan-DPs and Bulel-DPs did not affect monolayer viability and cytoskeleton structure. Overall, our findings suggest that both Tritordeum cultivars could be potential candidates for mitigating the toxicity of wheat flour.

Identification of RNAi hypoallergic bread wheat lines for wheat-dependent exercise-induced anaphylaxis patients

Wheat-dependent exercise-induced anaphylaxis (WDEIA) is one of the most severe forms of wheat allergy. It occurs in patients when they exercise after ingesting wheat-containing foods. Nowadays, the only possible alternative for WDEIA patients is to avoid such foods. This study investigated the potential of six RNA of interference (RNAi) wheat lines with low-prolamin content as alternatives for WDEIA patients. For that purpose, a high performance-liquid chromatography (HPLC) analysis was performed to evaluate differences in gluten protein fractions among these lines. Next, western blots were conducted to measure the immunoglobulin E (IgE) reactivity to wheat proteins in sera from five WDEIA patients. Additionally, monoclonal antibodies (moAb) recognition sites and the IgE binding sites were searched in all peptides identified by LC-MS/MS after protein digestion. The results showed a 61.4%-81.2% reduction in the gliadin content of the RNAi lines, accompanied by an increase in their high-molecular weight (HMW) glutenin content compared to the wild type bread wheat line (WT). In all cases, the reduction in gliadin content correlated with a decrease in IgE reactivity observed in the sera of WDEIA patients, highlighting the E82 and H320 lines. These two RNAi lines exhibited a ≤90% reduction in IgE reactivity. This reduction could be attributed to an absence of IgE binding sites associated with α- and ω5-gliadins, which were present in the WT. Overall, these lines offer a potential alternative for foodstuff for individuals with WDEIA.

Unraveling the celiac disease-related immunogenic complexes in a set of wheat and tritordeum genotypes: implications for low-gluten precision breeding in cereal crops

The development of low-gluten immunogenic cereal varieties is a suitable way to fight the increment of pathologies associated with the consumption of cereals. Although RNAi and CRISPR/Cas technologies were effective in providing low-gluten wheat, the regulatory framework, particularly in the European Union, is an obstacle to the short- or medium-term implementation of such lines. In the present work, we carried out a high throughput amplicon sequencing of two highly immunogenic complexes of wheat gliadins in a set of bread and durum wheat, and tritordeum genotypes. Bread wheat genotypes harboring the 1BL/1RS translocation were included in the analysis and their amplicons successfully identified. The number of CD epitopes and their abundances were determined in the alpha- and gamma-gliadin amplicons, including 40k-γ-secalin ones. Bread wheat genotypes not containing the 1BL/1RS translocation showed a higher average number of both alpha- and gamma-gliadin epitopes than those containing such translocation. Interestingly, alpha-gliadin amplicons not containing CD epitopes accounted for the highest abundance (around 53%), and the alpha- and gamma-gliadin amplicons with the highest number of epitopes were present in the D-subgenome. The durum wheat and tritordeum genotypes showed the lowest number of alpha- and gamma-gliadin CD epitopes. Our results allow progress in unraveling the immunogenic complexes of alpha- and gamma-gliadins and can contribute to the development of low-immunogenic varieties within precision breeding programs, by crossing or by CRISPR/Cas gene editing.

Comparative compositions of grain of tritordeum, durum wheat and bread wheat grown in multi-environment trials

Three genotypes each of bread wheat, durum wheat and tritordeum were grown in randomized replicated field trials in Andalusia (Spain) for two years and wholemeal flours analysed for a range of components to identify differences in composition. The contents of all components that were determined varied widely between grain samples of the individual species and in most cases also overlapped between the three species. Nevertheless, statistically significant differences between the compositions of the three species were observed. Notably, tritordeum had significantly higher contents of protein, some minerals (magnesium and iron), total phenolics and methyl donors. Tritordeum also had higher levels of total amino acids (but not asparagine) and total sugars, including raffinose. By contrast, bread wheat and tritordeum had similar contents of the two major dietary fibre components in white flour, arabinoxylan and β-glucan, with significantly lower contents in durum wheat.