Molecular characterization and functional properties of avenin-like b gene TuALPb7As in Triticum urartu

Avenin-like storage proteins affect the rheological properties and processing quality of common wheat. Triticum urartu, the A-genome donor of polyploid wheat, shows abundant variation in its glutenin subunits. In this study, the variability in avenin-like b genes was evaluated in 74 T. urartu accessions. High levels of polymorphism were demonstrated in the analyzed sequence, resulting in the discovery of 18 novel TuALPb7A alleles (TuALPb7A-A-TuALPb7A-R). There were nucleotide sequence differences in 18 locations, which, due to synonymous mutations, resulted in amino acid changes. The polymorphic sites were located in the N-terminus, repetitive region (Left), repetitive region (Right) and C-terminus domains. The position of some cysteine residues was different in T. urartu and Aegilops tauschii accessions. Phylogenetic analysis divided the avenin-like b (ALPb) genes into two groups. The ALPb-7A alleles, containing 18 TuALPb7As, were distributed in the first group, whereas the ALPb-4A alleles were present in another. Avenin-like proteins encoded by four alleles (TuALPb7A-G, TuALPb7A-O, TuALPb7A-K and TuALPb7A-C) were expressed on a large scale and purified to estimate the effect on dough mixing properties. Mixograph testing demonstrated that these proteins could improve the functional properties of dough, including the mixing time, peak dough resistance and breakdown in resistance. The avenin-like b genes hold rich genetic alleles in T. urartu, and can improve the functional properties of dough. The new favourable alleles discovered will provide breeding materials and a theoretical basis for wheat quality improvement.