Breeding a fungal gene into wheat

Every year, infection of wheat by the fungus Fusarium graminearum results in losses of ∼28 million metric tons of wheat grain, valued at $5.6 billion. The fungus reduces yields but also contaminates harvests with trichothecene toxins such as deoxynivalenol (DON; also called vomitoxin because of its effects on mammals) that render grain too poisonous to use. The disease is becoming more prevalent because of increasing cultivation of maize (also a host for the fungus) and reduced tillage (ploughing) agriculture, which promotes fungal survival on last season's plant debris. On page 844 of this issue, Wang et al. reveal the molecular identity of the Fusarium head blight 7 (Fhb7) gene, which encodes a glutathione S-transferase that detoxifies DON. This gene was acquired through a “natural” fungus-to-plant gene transfer in a wild wheat relative. This naturally occurring genetically modified (GM) wheat strain is therefore exempt from regulation and can be grown directly by farmers.