Newly characterized protein has potential to save US farmers millions annually

Instead of turning carbon into food, many plants accidentally make a plant-toxic compound during photosynthesis that is recycled through a process called photorespiration. 

University of Illinois and USDA/ARS researchers report in Plant Cell the discovery of a key protein in this process, which they hope to manipulate to increase plant productivity.

"Photorespiration is essential for C3 plants, such as rice and soybeans, but operates at the massive expense of fixed carbon and energy," said project lead Don Ort, USDA/ARS scientist and the Robert Emerson Professor of Plant Biology at Illinois. "We have identified photorespiration as a primary target to improve photosynthetic efficiency as a strategy to improve crop yield. Successfully re-engineering photorespiration requires deep knowledge of the process, for which understanding of transport steps is most lacking."

Related to a family of transport proteins that move bile around in animals, the newly discovered role of the plant protein Bile Acid Sodium Symporter 6 (BASS6) is to transport the toxic product glycolate out of the chloroplast where it is recycled into a useful sugar molecule (glycerate) through a series of chemical reactions, which release carbon dioxide and harmful ammonia while sacrificing energy.

"We could feed around 200 million people with the calories lost to photorespiration each year just in the Midwestern United States," said co-author author Berkley Walker, an Alexander von Humboldt Postdoctoral Fellow at the University of Düsseldorf, citing his recently published simulations. "While we can't get all that yield back, even saving 5% of the energy in lost in photorespiration would be worth millions of dollars annually."