Alfalfa survives cold
When the mercury takes a plunge, people bundle up. But important crops like alfalfa, which often spend long winters in the field, are laid bare to the elements. To help the crop survive, Guelph researchers have introduced new genes into standard alfalfa plants and created the world’s first freeze-tolerant transgenic alfalfa.
In the scientific journal Plant Physiology, a research team led by crop science professors Bryan McKersie and Steve Bowley tells how — after six years of laboratory and field tests — they have produced a plant defence system. It makes alfalfa more tolerant to environmental stresses such as freezing and drought.
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“This alfalfa has undergone harsh field trials and tough laboratory tests,” says McKersie. “It has performed well.”
Key to their efforts is beefed-up superoxide dismutase (SOD), a gene native to alfalfa. It breaks down stress-activated oxygen molecules — which attack cell membranes during freezing and drought and cause decay — into substances the plant can use as energy or emit as waste.
The project began in 1988 when McKersie was on sabbatical in Belgium at the University of Ghent and its sister company Plant Genetic Systems. There, he participated in a project to isolate the SOD gene and modify it to automatically raise SOD levels during stress.
Later, he brought the project home with him, shuttled the SODs back into the alfalfa and linked them to environmental stress tolerance. In 1992, the modified alfalfa was planted at the Elora, Ont. research station, and the research crew began putting the plants through lab tests.
Out in the field, trials ran through last year and into this winter. Bowley said the transgenic alfalfa delivered a more rugged performance than its non-transgenic counterparts during the past two summers and winters.
McKersie said this genetic defence might help other plants beat freezing: “Perhaps our success with alfalfa will have a broad application.”
- University of Guelph
