Giant Grass Offers Clues to Growing Corn in Cooler Climes

Researchers at the University of Illinois have recently discovered why the giant grass Miscanthus x giganteus can survive cool climates. The giant perennial grass which is a biofuel feedstock is a C4 plant which converts sunlight into leaves and stalks more efficiently than the C3 plants. When the researchers led by Stephen Long compared the levels of proteins in plants grown in warm and cold conditions, 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.

PPDK catalyzes the formation of starches from carbon dioxide in C4 plants. PPDK is made up of four subunits which tend to disassemble at low temperatures. However, studies made by post-doctoral fellow Dafu Wang showed that when the protein is expressed in bacteria E.coli in large amounts it becomes resistant to cold. “At higher concentration the protein creates its own microenvironment in the cold that it doesn’t come apart. This appears to be the secret of success for Miscanthus at low temperature: Expressing more of the protein allows it to photosynthesize at low temperature where corn can’t”, Long said. The group is now strategizing ways to develop a corn plant that will express the gene at high levels to determine if that will make the corn more tolerant of low temperatures.

See the press release for more details at: http://www.news.uiuc.edu/news/08/0915coolgrass.html