Variation in the tonoplast cadmium transporter heavy metal ATPase 3 (HMA3) homolog gene in Aegilops tauschii

The functionality of HMA3 is a key determinant controlling Cd accumulation in the shoots and grains of plants. Wild relatives of modern crop plants can serve as sources of valuable genetic variation for various traits. Here, resequencing of HMA3 homoeologous genes from Aegilops tauschii (the donor of the wheat D genome) was carried out to identify natural variation at both the nucleotide and polypeptide levels. HMA3 homoeologs are highly conserved, and 10 haplotypes were revealed based on 19 single nucleotide polymorphisms (eight induced single amino acid residue substitutions, including 2 altered amino acids in transmembrane domains) in 80 widely distributed Ae. tauschii accessions. The results provide genetic resources for low/no Cd concentration wheat improvement.