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

Qiang Su,Ke Wang,Zengyan Zhang

doi:10.3390/ijms21020647

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.

Highlights

Bread wheat (Triticum aestivum L.) is an important food crop, feeding ≈35% of the world’s population [1]
The current results indicated that DmAMP1W peptide encoded by the synthesized DmAMP1W inhibited against growths of R. cerealis and B. sorokiniana, and DmAMP1W-expressing transgenic wheat plants displayed enhanced resistance to both fungal pathogens
The open-reading-frame sequence (ORF) of DmAMP1W was artificially synthesized according to wheat favor codons

Summary

Introduction

Bread wheat (Triticum aestivum L.) is an important food crop, feeding ≈35% of the world’s population [1]. R. cerealis reproduces asexually and exists primarily as vegetative mycelium and/or sclerotia [5]. It can infect the roots and basal stems at any time during the wheat growing season, and in turn can devastate the transport of tissues in stems of wheat and obstruct transportation of nutrition substances [3,6]. Common root rot, caused by the soil-borne fungus Bipolaris sorokiniana, is another important disease of wheat [7]. It is difficult to breed wheat varieties with resistance to sharp eyespot and common root rot by using traditional method, since no effective resistance accessions are available. Introducing alien genes conferring disease resistance by genetic transformation is an efficient alternative

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Conclusion