New research from China has demonstrated that a novel technique to enhance photosynthetic efficiency in rice crops can increase grain yields by up to 27 percent. The study also shows other recent demonstrations of food bioengineering designed to enhance worldwide food productivity by improving the photosynthesis process in crops.
Scientists are working to increase crop yields to enhance the efficiency of photosynthesis. Around 20-50% of the energy a plant produces through photosynthesis can be diverted into a process called photorespiration.
However, one scientist recently described photorespiration as "anti-photosynthesis." Plants generate the chemical energy they need to grow by grabbing carbon dioxide molecules from the surrounding environment. Around 25% of the time the plant incorrectly collects oxygen molecules, creating a plant-toxic byproduct that disrupts the entire photosynthesis process, and ultimately releases carbon dioxide. Photorespiration is the process plants use to remove these problematic byproducts.
One recent strategy developed to increase photosynthetic efficiency focus on engineering more efficient photorespiration pathways within a plant. These techniques essentially engineered alternate routes within a plant cell so the toxic byproducts could be removed using less energy.
The new study, from a team of scientists in China, demonstrates a different strategy to increase a plant's energy efficiency. This technique diverts carbon dioxide produced during photorespiration to photosynthesis. The process is named GOC bypass and utilizes three enzymes to convert a molecule called glycolate into carbon dioxide.
The results were impressive in field tests using rice crops, with the GOC bypass plants displaying overall grain yield improvements between 7 and 27%. Photorespiratory rates were suppressed by up to 31% and net photosynthetic rates increased up to 2%.
The researchers suggest these results can be further optimized through larger field testing and experimenting with different rice varieties. Future work will also investigate whether the technique applies to other food crops like potatoes. Though there are many questions that need to be resolved before these kinds of engineered crops can be widely deployed.
"Although we don't expect this approach would affect the taste of these plants, both the nutritional quality and taste are yet to be comprehensively evaluated by independent labs and governmental agencies," said Xin-Xiang Pen, senior author on the new research.
