Screening new gene markers for gluten detection in foods

• Three real-time PCR systems to detect gluten-containing cereals were developed.
• DNA sequences encoding α2-gliadin, agglutinin isolectin and thioredoxin h proteins.
• Assessing the performance of the three methods.
• α2-Gliadin method revealed the highest sensitivity.
• High specificity for detecting wheat, barley and rye.

In the present work, three DNA sequences encoding wheat proteins (α2-gliadin, agglutinin isolectin and thioredoxin h) were compared to trace gluten-containing cereals in food products. Quantitative real-time PCR methods using hydrolysis probes were successfully developed to target the three sequences for the detection of wheat DNA. The comparison of the three systems highlights the best sensitivity when tracing the α2-gliadin marker sequence, showing an absolute limit of detection (LOD) of 2 pg of wheat DNA and a relative LOD of 0.005% (50 mg/kg) of wheat in soybean, which corresponds to 4.5 mg/kg of gluten. All the systems reveal high specificity for detecting other gluten-containing cereals, such as barley and rye. Therefore, the developed real-time PCR systems can be used as non-immunological tools to confirm the presence of gluten-containing cereals in foods, towards the safety of celiac patients and wheat allergic individuals.