A new study has shed light on how plant evolution and trait selection works based on how maize has adapted to high elevations and cold temperatures using borrowed gene from corn.
Researchers at North Carolina State University show that an important gene in maize called HPC1 modulates certain chemical processes that contribute to flowering time, and has its origins in “teosinte mexicana,” a precursor to modern-day corn that grows wild in the highlands of Mexico.
Maize grown at higher altitudes, like the highlands of Mexico, needs special accommodations in order to grow successfully. The colder temperatures in these mountainous regions put maize at a slight disadvantage when compared with maize grown at lower elevations and higher temperatures.
That’s where the HPC1 gene comes in, the researchers say. In corn varieties grown in low elevations, including most of the corn grown in the United States, the gene breaks down phospholipids that in other species have been shown to bind to important proteins that accelerate flowering time.
In the mountains, though, the gene misfires, but to the benefit of highland maize.
In the paper, the researchers show the results of vast experiments throughout Mexico – in lowlands and highlands – in which the highland version of the gene was present. They found that corn with the highlands version of the gene flowered one day earlier than plants without that version of the gene. Meanwhile, corn grown in the lowlands with the highlands version of the gene flowered one day later than plants without that gene version.
The study also examined maize’s evolution through thousands of years of farmer selection throughout the Western Hemisphere. Native Americans domesticated maize thousands of years ago in southwest Mexico from a wild plant called teosinte parviglumis and, with great ingenuity, brought and adapted maize across the Americas – from the deserts of Arizona and Perú to the humid forests of Yucatán and Colombia, including up to the Mexican highlands, where maize was crossed with another wild teosinte plant – teosinte mexicana.
In the study, the researchers showed that genetic pieces from teosinte mexicana – namely the highlands version of HPC1 – have been retained in modern-day maize.
The study also showed the highlands variant of HPC1 in corn grown in Canada, the northern United States and northern Europe – which makes sense due to the colder climate found in those locations.
The NC State researchers are now examining the role of this and other genes involved in phosphorus metabolism to learn more sustainable ways of growing maize and perhaps to bring more teosinte mexicana into modern corn.