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 in Science Advances, showed that transgenic corn plants infected with the fungus suppressed toxin levels below detectable limits.
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.
The modified corn plants carry a genetic blueprint for small RNA molecules, each only about 20 base pairs long, only in the edible kernels, not the whole plant.
"The corn is constantly producing that RNA during the entire development of the kernel," Schmidt explained.
In their experiments, the team infected corn plants with Aspergillus and let them grow for one month.
The team took the project a step further and investigated overall gene expression in kernels to see if the transgenic corn plants come with undesired side effects.
This involved co-author Rod Wing’s laboratory, also of the UA’s School of Plant Sciences, to compare thousands of RNA transcripts between the nontransgenic control kernels and transgenic kernels.
"This corn plant would be like any other," she said.