Molecular characterization and evolutionary relationships of avenin-like b gene in Aegilops speltoides

The avenin-like storage protein is a novel seed storage protein, it directly affects the processing quality of wheat flour. Aegilops speltoides is a diploid B genome donor species of the common wheat, which possesses plenty of variability. In this study, 43 avenin-like b alleles were discovered in 26 Ae. speltoides accessions. The nucleotide sequence analysis revealed genetic diversity of these alleles in Ae. speltoides, with a range of 1–5 different kinds of avenin-like b allele sequences detected in some accession. The length of avenin-like b alleles was 852, 855, or 858 bp, with 110 mutated sites. The alleles encoded avenin-like b proteins with 283 or 284 amino-acid residues. The amino acid sequences of nine avenin-like b alleles had 17 Cys residues whereas 34 alleles had 18 Cys residues. The repetitive region (left and right) domains and the C-terminus domain had changed from cysteine to tyrosine (Cys→Tyr). Ae. speltoides had greater genetic diversity in the avnenin-like b gene than did the polyploid wheats. The phylogenetic analysis showed that the avenin-like b genes of Ae. speltoides had high homology with those of 4A of tetraploid wheat and common wheat.