Giant grass offers clues to growing corn in cooler climes, researchers report

A protein that gives Miscanthus an advantage in cool weather may be used to develop cold-tolerant corn varieties. Click here for more information.

A giant perennial grass used as a biofuels source has a much longer growing season than corn, and researchers think they've found the secret of its success. Their findings offer a promising avenue for developing cold-tolerant corn, an advance that would significantly boost per-acre yields.

The new study, from researchers at University of Illinois, appears this month in Plant Physiology Preview.

Miscanthus x giganteus is one of the most productive grasses known. It is able to capture the sun's energy even as cool temperatures shut down photosynthesis in other plants.

In Illinois, green Miscanthus leaves emerge up to six weeks before corn can be planted. Miscanthus thrives into late October, while corn leaves wither at the end of August.

Postdoctoral fellow Dafu Wang examines photosynthesis in corn and Miscanthus in controlled simulated cold conditions. Click here for more information.

Corn and Miscanthus are C4 plants, which are more efficient than C3 plants in converting sunlight into leaves and stalks. (C3 and C4 simply refer to the number of carbon atoms in a molecule critical to photosynthesis.)

"The C4 process differs from C3 in having just four extra steps in its metabolism," said Stephen Long, a professor of crop sciences and principal investigator on the study. "There are four extra proteins in this process, so we assumed that these proteins are related to low temperature tolerance."

When they compared the levels of these proteins in plants grown in warm and cold conditions, the researchers noticed that one of the proteins, pyruvate phosphate dikinase (PPDK), was present at much higher levels in the Miscanthus leaves grown at cool temperatures than in the leaves of either corn or Miscanthus grown in warmer conditions.

Although photosynthesis declined in both plants when they were first subjected to cool temperatures, after two days, photosynthesis rebounded in the Miscanthus.