Researchers at the University of Arizona have found a promising way to prevent the loss of millions of tons of crops to a fungus each year, offering the potential to dramatically improve food security, especially in developing countries. The team's approach uses transgenic corn plants that produce small RNA molecules that prevent fungi from producing aflatoxin, highly toxic substances that can render an entire harvest unsafe for human consumption even in small amounts. Although extensive field testing will have to precede widespread application of the new technique in agricultural settings around the world, the results of the study, published online on March 10, 2017 in Science Advances, showed that transgenic corn plants infected with the fungus suppressed toxin levels below detectable limits. Crops all over the world are susceptive to infection by fungi of various Aspergillus species, a fungus that produces secondary metabolites known as aflatoxins. These compounds have been implicated in stunting children's growth, increasing the risk for liver cancer, and making people more susceptible to diseases such as HIV and malaria. The open-access Science Advances article is titled “Aflatoxin-free transgenic maize using host-induced gene silencing.” Unlike in the U.S., where crops intended for human consumption are tested for aflatoxin and incinerated once levels approach 20 parts per billion (equivalent to one drop of water in a 22,000-gallon pool), no testing is available in many developing parts of the world, especially in Africa, where millions of people depend on consuming what they harvest. There, toxin levels up to 100,000 parts per billion have been measured, says study leader Dr. Monica Schmidt, an Assistant Professor in the UA's School of Plant Sciences and a member of the UA's BIO5 Institute.
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