Fusarium graminearum is the fungal pathogen that causes globally important 
diseases of cereals and produces mycotoxins such as deoxynivalenol (DON). Owing 
to the dearth of available sources of resistance to Fusarium pathogens, 
characterization of novel genes that confer resistance to mycotoxins and 
mycotoxin-producing fungi is vitally important for breeding resistant crop 
varieties. In this study, a wheat methionyl-tRNA synthetase (TaMetRS) gene was 
identified from suspension cell cultures treated with DON. It shares conserved 
aminoacylation catalytic and tRNA anticodon binding domains with human MetRS and 
with the only previously characterized plant MetRS, suggesting that it functions 
in aminoacylation in the cytoplasm. However, the TaMetRS comprises a typical 
nuclear localization signal and cellular localization studies with a 
TaMetRS::GFP fusion protein showed that TaMetRS is localized in the nucleus. 
Expression of TaMetRS was activated by DON treatment and by infection with a 
DON-producing F. graminearum strain in wheat spikes. No such activation was 
observed following infection with a non-DON-producing F. graminearum strain. 
Expression of TaMetRS in Arabidopsis plants conferred significant resistance to 
DON and F. graminearum. These results indicated that this DON-activated TaMetRS 
gene may encode a novel type of MetRS in plants that has a role in defense and 
detoxification.