In C3-type plants, Rubisco catalyzes the capture of CO2 from the atmosphere during photosynthesis but about 35% of the time Rubisco binds oxygen instead of CO2 producing a carbon compound called glycolate that cannot be used in photosynthesis. In fact, glycolate is toxic to some photosynthetic enzymes. The plant makes the best of a bad situation by salvaging a portion of carbon in glycolate via a complex network of enzyme reactions in multiple organelles into 3-phosphoglycerate (PGA), which can be used in photosynthesis. This process, called photorespiration, recovers 75% of the carbon lost by the Rubisco oxygenation reaction but expends a large amount of metabolic energy in the recovery process. Some bacteria have simpler pathways for converting glycolate to PGA that require less energy. RIPE is replacing the native pathway with these more efficient bacterial pathways and other novel synthetic pathways in order to make photosynthesis more efficient.
Can you imagine the entire population of the United States, Canada, Mexico, Brazil, the United Kingdom and France going hungry? You don’t need to imagine.
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.