Overexpression of nepenthesin HvNEP-1 in barley endosperm reduces fusarium head blight and mycotoxin accumulation

Abstract

Fusarium head blight (FHB) causes substantial losses of yield and quality in grains, both in the field and in post-harvest storage. To date, adequate natural genetic resistance is not available for the control of FHB. This study reports the cloning and overexpression of a barley (Hordeum vulgare L.) antifungal gene, nepenthesin 1 (HvNEP-1), in the endosperm of barley grains. Transgenic barley lines overexpressing HvNEP-1 substantially reduced FHB severity and disease progression after inoculation with Fusarium graminearum or Fusarium culmorum. The transgenic barley also showed reduced accumulation of the mycotoxin deoxynivalenol (DON) in grain, far below the minimum value allowable for food. Semi-field evaluation of four HvNEP-1 transgenic lines revealed substantial reduction of FHB severity and progression as compared with the control H. vulgare cultivar Golden promise (GP) plants. Our study demonstrated the utility of HvNEP-1 for the control of FHB in barley, and possibly other grains such as wheat and maize.