Thomas Slewinski is onto something very big for agriculture and global food production. The Cornell University plant biology researcher has discovered a maize (corn) gene that could lead to new varieties of staple crops with 50% higher yields. It has huge implications for feeding a projected word population of 9.5 billion people by 2050.
The gene, called Scarecrow, is in C4 plants such as corn, sorghum, sugarcane and certain grasses. It controls a special leaf structure, known as Kranz anatomy, which helps these plants convert carbon dioxide for more efficient photosynthesis than C3 plants, explains Slewinski. C3 food crops include rice, wheat, barley and potatoes.
"Researchers have been trying to find the underlying genetics of Kranz anatomy so we can engineer it into C3 crops," elaborates Slewinski, a researcher in the Cornell lab of Plant Biologist Robert Turgeon.
"There's still a lot to be learned," adds Turgeon. "But now the barn door is open and you are going to see people working on this Scarecrow pathway."
The promise of transferring C4 mechanisms into C3 plants has been scientifically pursued and funded on a global scale for decades. C3 plants can't grow in hot, dry areas because an in-plant enzyme, commonly referred to as RuBisCO, incorporates more oxygen than carbon as temperatures increase. That leads to photorespiration, causing a net loss of carbon and nitrogen and limiting growth.
Genetic engineering potential|
If C4 photosynthesis is successfully transferred to C3 plants through genetic engineering, it would make C3 plants better suited to drought, intense sunlight, heat and low nitrogen rates. Farmers could grow wheat and rice in hotter, dryer environments with less fertilizer, while possibly increasing yields by half, contend Slewinski and Turgeon.
By looking closely at plant evolution and anatomy, Slewinski recognized that the bundle sheath cells in leaves of C4 plants were similar to endodermal cells surrounding vascular tissue in roots and stems.
Slewinski found experimental maize with Scarecrow genes that governed endodermal cells in roots.
Next step is to successfully transfer those genes into C3 crops and develop new varieties. The study was funded by the National Science Foundation and the U.S. Department of Agriculture.