Addition of Aegilops U and M Chromosomes Affects Protein and Dietary Fiber Content of Wholemeal Wheat Flour

Marianna Rakszegi, István Molnár, Alison Lovegrove, Éva Darkó, András Farkas, László Láng, Zoltán Bedő, Jaroslav Doležel, Márta Molnár-Láng, Peter Shewry

Cereal grain fiber is an important health-promoting component in the human diet. One option to improve dietary fiber content and composition in wheat is to introduce genes from its wild relatives Aegilops biuncialis and Aegilops geniculata. This study showed that the addition of chromosomes 2U(g), 4U(g), 5U(g), 7U(g), 2M(g), 5M(g), and 7M(g) of Ae. geniculata and 3U(b), 2M(b), 3M(b), and 7M(b) of Ae. biuncialis into bread wheat increased the seed protein content. Chromosomes 1U(g) and 1M(g) increased the proportion of polymeric glutenin proteins, while the addition of chromosomes 1U(b) and 6U(b) led to its decrease. Both Aegilops species had higher proportions of β-glucan compared to arabinoxylan (AX) than wheat lines, and elevated β-glucan content was also observed in wheat chromosome addition lines 5U, 7U, and 7M. The AX content in wheat was increased by the addition of chromosomes 5U(g), 7U(g), and 1U(b) while water-soluble AX was increased by the addition of chromosomes 5U, 5M, and 7M, and to a lesser extent by chromosomes 3, 4, 6U(g), and 2M(b). Chromosomes 5U(g) and 7M(b) also affected the structure of wheat AX, as shown by the pattern of oligosaccharides released by digestion with endoxylanase. These results will help to map genomic regions responsible for edible fiber content in Aegilops and will contribute to the efficient transfer of wild alleles in introgression breeding programs to obtain wheat varieties with improved health benefits. Key Message: Addition of Aegilops U- and M-genome chromosomes 5 and 7 improves seed protein and fiber content and composition in wheat.