Researchers believe they can boost crop productivity by as much as 40 per cent by engineering plants to improve how efficiently they convert the sunlight into energy via photosynthesis.
Researchers from the University of Illinois and U.S. Department of Agriculture Agricultural Research Service report in the journal Science that crops engineered with a photorespiratory shortcut are 40 per cent more productive in real-world agronomic conditions.
“We could feed up to 200 million additional people with the calories lost to photorespiration in the Midwestern U.S. each year,” said principal investigator Donald Ort, the Robert Emerson Professor of Plant Science and Crop Sciences at Illinois’ Carl R. Woese Institute for Genomic Biology.
This landmark study is part of Realizing Increased Photosynthetic Efficiency (RIPE), an international research project that is engineering crops to photosynthesize more efficiently to sustainably increase worldwide food productivity with support from the Bill & Melinda Gates Foundation, the Foundation for Food and Agriculture Research (FFAR), and the U.K. Government’s Department for International Development (DFID).
Photosynthesis uses the enzyme Rubisco — the planet’s most abundant protein — and sunlight energy to turn carbon dioxide and water into sugars that fuel plant growth and yield. Over millennia, Rubisco has become a victim of its own success, creating an oxygen-rich atmosphere.
Unable to reliably distinguish between the two molecules, Rubisco grabs oxygen instead of carbon dioxide about 20 per cent of the time, resulting in a plant-toxic compound that must be recycled through the process of photorespiration.
Photorespiration normally takes a complicated route through three compartments in the plant cell. Scientists engineered alternate pathways to reroute the process, drastically shortening the trip and saving enough resources to boost plant growth by 40 per cent.
Over two years of replicated field studies, they found that these engineered plants developed faster, grew taller, and produced about 40 per cent more biomass, most of which was found in 50-per-cent-larger stems.
The team tested their hypotheses in tobacco: an ideal model plant for crop research because it is easier to modify and test than food crops, yet unlike alternative plant models, it develops a leaf canopy and can be tested in the field. Now, the team is translating these findings to boost the yield of soybean, cowpea, rice, potato, tomato, and eggplant.