Monday, July 5, 2010

MDROs in agriculture

Humans aren't the only ones battling multi-drug resistant organisms (MDROs), wheat, as it turns out, is also susceptible to fast evolving infectious superbugs. A story on the wheat rust in last week's Economist reminded me of our ongoing battle with MDROs.

Wheat rust is a type of fungal infection that attacks the wheat plant's stem by forming red pustules on the plant and eventually causes the crops to die. The disease is highly infectious - responsible for killing one fifth of America's wheat harvest in the first half of the 20th century.

The discovery of a wheat rust resistant gene in the 1940s led to genetically modified wheat seeds that were resistant to the fungus and seemingly eliminated the disease for the next 40 years.

Scientists have now found that the fungus is making a comback and in a more virulent form. The first case was discovered in 1998 in Uganda. The fungus has evolved to overcome the resistant gene in the wheat plant and has become more lethal to the crop. The new variant, called Ug99, quickly spread to Kenya and Ethiopia and then to the Middle East, evolving into new forms as it spreads. Scientists fear that it will make its way to Southeast Asia and the Far East where 3/5 of world's wheat is grown.

In order to combat the fungus, scientists have developed over 60 experimental varieties of wheat with multiple resistant genes. However, whether or not any of them would work remains to be seens. An even bigger challenge is figuring out how to distribute the new seeds to all of world's wheat growing regions.

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