A team of scientists led by Pennsylvania State University has recently identified a gene encoding a transcription factor (a protein useful for converting DNA into RNA) which triggers a genetic sequence that enables corn roots to acquire more water and nutrients. This finding could lead to the breeding of corn crops able to withstand droughts and low-nitrogen soil conditions, and thus improve global food security.
The newly discovered trait – known as a phenotype – is called “root cortical aerenchyma” and plays a crucial role in the development of air passages in the roots which enables them to explore the soil more efficiently and capture larger amounts of water and nutrients from dry, infertile soils.
By using powerful genetic tools developed in previous studies and conducting a series of field experiments that lasted over a decade, the experts identified the gene that causes corn to express cortical aerenchyma, which they named bHLH121.
“We first performed the field experiments that went into this study starting in 2010, growing more than 500 lines of corn at sites in Pennsylvania, Arizona, Wisconsin, and South Africa,” said lead author Hannah Schneider, an assistant professor of Crop Physiology at the Wageningen University & Research in the Netherlands, who conducted this study during a postdoctoral fellowship at Penn State. “I worked at all those locations. We saw convincing evidence that we had located a gene associated with root cortical aerenchyma.”
The discovery of the bHLH121 gene’s importance in root cortical aerenchyma formation provides a new marker for plant breeders to select corn varieties with improved soil exploration and yield under suboptimal conditions. As the climate continues to warm, creating crops with better drought tolerance and nitrogen and phosphorous capture capacities is crucial.
“Those are super-important qualities – both here in the U.S. and around the world. Droughts are the biggest risk to corn growers and are worsening with climate change, and nitrogen is the biggest cost of growing corn, from both a financial and environmental perspective. Breeding corn lines more efficient at scavenging for the nutrient would be a major development,” concluded senior author Jonathan Lynch, a professor of Plant Sciences at Penn State.
The study is published in the journal Proceedings of the National Academy of Sciences.
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