Molecular phylogenetic and sequence variation analysis of dimeric α-amylase inhibitor genes in wheat and its wild relative species

Dimeric alpha-amylase inhibitors serve protection against insects that are highly dependent on starch for their energy. In order to study the molecular evolution and sequence variation, we have sequenced dimeric α-amylase inhibitors gene from different genomes in Triticeae including Indian bread and durum wheat genotypes. Using BLAST, obtained sequences show very high homology with other inhibitors available at GenBank database and had common conserved 10 cysteine residues. Investigated frequency of significant SNPs in the α-amylase inhibitor gene was 1 out of 60 bases. The phylogenetic analysis based on deduced amino acid sequences revealed that the genes encoding dimeric α-amylase inhibitors formed three groups and genes isolated from Indian bread wheat clustered with 0.19 inhibitors. In addition, we predicted that dimeric α-amylase inhibitors co-localized into chloroplast and mitochondria expect for the sequences isolated from Aegilops tauschii. Fingerprinting analysis done with ScanProsite confirmed biologically meaningful signatures. Multiple sequence alignment of dimeric α-amylase proteins from different plant species revealed a conserved secondary structure region, indicating homology at the sequence and structural levels. Analysis of the protein sequences obtained from wheat and its wild related species are very similar, indicates a highest conservation of these proteins.