Figure: ARS plant physiologist William Hay examines wheat plants exposed to elevated CO2 levels in growth chamber experiments. Photo Source: ARS

Scientists from the U.S. Department of Agriculture's Agricultural Research Service (ARS) are preparing wheat for climate challenges ahead.

The scientists are subjecting more than a dozen wheat varieties to two major stressors. The first comes from exposure to carbon dioxide (CO2) levels of up to 1,000 parts per million—an atmospheric concentration of the greenhouse gas projected for the turn of the century absent mitigation measures. The other stressor is infection by the insidious fungus Fusarium graminearum. This fungus causes head blight, a costly disease of wheat, barley, and oat crops worldwide that can damage the grain and contaminate it with mycotoxins, rendering the grain unsafe for food or feed use.

Initially, the scientists compared Alsen, a hard red spring wheat that carries two commonly used genetic sources of blight resistance, to Norm, a popular high-yielding but susceptible wheat variety. Alsen suffered a greater loss in grain nutritional content than Norm, resulting in increased mycotoxin production by certain Fusarium strains. In subsequent experiments, the researchers observed similar responses in an additional nine resistant and six susceptible varieties.

The team is also studying how the fungus itself behaves in wheat plants exposed to high CO2 levels and observed that the severity of blight and production of mycotoxins like deoxynivalenol depends on the fungal strain and wheat variety attacked. They also found that besides protein and minerals, Alsen plants suffered a drop in oleic and linoleic fatty acids, which normally contribute to resistance to blight and other fungal diseases.

For more details, read the article in ARS News & Events.