Enriching novel Glu-Ax alleles and significantly strengthening gluten properties of common wheat through wide hybridization with wild emmer

Two hybrids, BAd7-209 and BAd7-210, were obtained by wide hybridization between wild emmer D97 and weak gluten cultivar CN16. They had a genetic background of common wheat, resulting from continuous selfing over nine times. These hybrids were better than CN16 in dough quality and processing quality tests. BAd7-210 was better than medium gluten wheat cultivar MM37, and BAd7-209 was far better than moderate to strong gluten wheat cultivar SM482. Through chromosome engineering, BAd7-210 possessed the 1Ax2.2 of male D97, and BAd7-209 had the 1Ax1.2 which was caused by complex variation because of cross-parents' genomic asymmetry. The open reading frames (ORFs) of two novel active Glu-Ax alleles 1Ax2.2 and 1Ax1.2 were 2496 bp and 2514 bp, encoding 830 and 836 amino acid residues, respectively. The 1Ax1.2 was the second longest Glu-Ax gene discovered to date, and it had two deletions and one insertion besides many single nucleotide polymorphisms (SNPs) compared with the 1Ax2.2 and 1Ax1. The longer polypeptide of 1Ax1.2 should explain why BAd7-209 has better processing quality than BAd7-210. Therefore, wild emmer could be effectively utilized to enrich the 1Ax alleles of common wheat through direct cross transferring and generating novel allele variation, which could significantly enhance the gluten strength.