New transcriptomic insights in two RNAi wheat lines with the gliadins strongly down-regulated by two endosperm specific promoters

Abstract

The gluten proteins of wheat grain are responsible for visco-elastic properties of flour, but they also trigger the immune-response of celiac disease. In this work, two low-gliadin RNA interference (RNAi) wheat lines that differ for the promoter driving the silencing (D-hordein and γ-gliadin promoters for D783 and D793 lines, respectively), were characterized at transcriptomic, and protein fraction levels in the grain. Silencing of gliadins provides a readjustment in the grain protein fractions that also affects to the non-gluten proteins (NGP), which were increased in both RNAi lines. Determination of wheat gluten by means of the R5 monoclonal antibody also showed a strong reduction in the content of gluten in both RNAi lines. Moreover, fructans, an oligosaccharide linked with the development of non-celiac wheat sensitivity (NCWS) were also significantly decreased in RNAi lines. The down-regulation of gliadins fractions also impacts to other metabolic processes, particularly on carbohydrate metabolism, enzyme regulator activity and response to stress. Genes and transcription factors regulated by ABA were up-regulated, which could suggest the implication of this phytohormone on the stress response observed in the RNAi lines.