Ecotopic Expression of the Antimicrobial Peptide DmAMP1W Improves Resistance of Transgenic Wheat to Two Diseases: Sharp Eyespot and Common Root Rot

Abstract

Wheat (Triticum aestivum L.) is an important staple crop. Sharp eyespot and common root rot are destructive diseases of wheat. Antimicrobial peptides (AMPs) are small peptides with broad-spectrum antimicrobial activity. In this study, we synthesized the DmAMP1W gene, encoding Dahlia merckii DmAMP1, and investigated the antifungal role of DmAMP1W in vitro and in transgenic wheat. Protein electrophoresis analysis and in vitro inhibition results demonstrated that the synthesized DmAMP1W correctly translated to the expected peptide DmAMP1W, and the purified peptide inhibited growths of the fungi Rhizoctonia cerealis and Bipolaris sorokiniana, the pathogenic causes of wheat sharp eyespot and common root rot. DmAMP1W was introduced into a wheat variety Zhoumai18 via Agrobacterium-mediated transformation. The molecular characteristics indicated that DmAMP1W could be heritable and expressed in five transgenic wheat lines in T1–T2 generations. Average sharp eyespot infection types of these five DmAMP1W transgenic wheat lines in T1–T2 generations decreased 0.69–1.54 and 0.40–0.82 compared with non-transformed Zhoumai18, respectively. Average common root rot infection types of these transgenic lines and non-transformed Zhoumai18 were 1.23–1.48 and 2.27, respectively. These results indicated that DmAMP1W-expressing transgenic wheat lines displayed enhanced-resistance to both sharp eyespot and common root rot. This study provides new broad-spectrum antifungal resources for wheat breeding.