Molecular analysis of dimeric α-amylase inhibitor genes in Indian wheat

Abstract

Various enzymes inhibitors act on key gut digestive hydrolysis of insects, including <i style="mso-bidi-font-style:normal">α</i>-amylase and proteinases. The <i style="mso-bidi-font-style:normal">α</i>-amylase inhibitors have been widely investigated for their possible use in strengthening the plant defense against insects those are highly dependable on starch as an energy source. In the present study, dimeric <i style="mso-bidi-font-style:normal">α</i>-amylase inhibitors (WDAIs) were isolated from three Indian bread wheat genotypes and their molecular diversities were characterized. The dimeric <i style="mso-bidi-font-style: normal">α</i>-amylase inhibitors shared very high homology (95%) with other inhibitors available at GenBank database and had common conserved cysteine residues C-X_n-C-X_n-C-X_n-CC-X_n-C-X-C-X_n-C-X_n-C-X_n-C. The phylogentic analysis based on deduced amino acid sequences revealed that the genes encoding dimeric <i style="mso-bidi-font-style:normal">α</i>-amylase inhibitors formed three groups and genes isolated from Indian bread wheat clustered with 0.19 inhibitor. In addition, three allele-specific markers were validated in diverse Indian bread wheat, durum, and wild species using genome allele-specific markers. The AS (allele specific)-PCR primers based on SNPs are valuable in wheat breeding for effective selection of genes for dimeric α-amylase inhibitors. Characterization of novel inhibitors of this family in wheat by specific primers based on SNPs could provide an explanation of the evolution of the multigene family encoding the dimeric <i style="mso-bidi-font-style:normal">α</i>-amylase inhibitors.