Fusarium head blight (FHB; scab), primarily caused by Fusarium graminearum, is a devastating disease of wheat worldwide. FHB causes yield reductions and contamination of grains with trichothecene mycotoxins such as deoxynivalenol (DON). The genetic variation in existing wheat germplasm pools for FHB resistance is low and may not provide sufficient resistance to develop cultivars through traditional breeding approaches. Thus, genetic engineering provides an additional approach to enhance FHB resistance. The objectives of this study were to develop transgenic wheat expressing a barley class II chitinase and to test the transgenic lines against F. graminearum infection under greenhouse and field conditions. A barley class II chitinase gene was introduced into the spring wheat cultivar, Bobwhite, by biolistic bombardment. Seven transgenic lines were identified that expressed the chitinase transgene and exhibited enhanced Type II resistance in the greenhouse evaluations. These seven transgenic lines were tested under field conditions for percentage FHB severity, percentage visually scabby kernels (VSK), and DON accumulation. Two lines (C8 and C17) that exhibited high chitinase protein levels also showed reduced FHB severity and VSK compared to Bobwhite. One of the lines (C8) also exhibited reduced DON concentration compared with Bobwhite. These results showed that transgenic wheat expressing a barley class II chitinase exhibited enhanced resistance against F. graminearum in greenhouse and field conditions.
Bibliographical noteFunding Information:
We are grateful to Dr John Mundy of the Carlsberg Research Laboratory, Copenhagen, Denmark for providing the barley chitinase cDNA. We would like to thank Dr Peter Quail (USDA-ARS, Plant Gene Expression Center, Albany, CA) for providing the pAHC25 and pAHC17 plasmids. We are indebted to Abigail Cole, Sarah Jutila, Alissa Cyrus, Karen J Wennberg, Amar M Elakkad, and Yanhong Dong for excellent technical assistance. Sanghyun Shin was supported by the Korean Research Foundation (KRF-2005-000-10035). This project was supported by funds from the USDA-ARS US Wheat and Barley Scab Initiative, the Minnesota Small Grains Initiative, and Minnesota Wheat Research and Promotion Council.
- Fusarium graminearum
- Fusarium head blight