Scientists have found a way to increase crop production by up to 47% by speeding up a process in plant metabolism called photorespiration. The findings could help improve crop resilience to stress caused by higher temperatures during the growing season and increase global food security.
Photorespiration causes some of the energy produced by photosynthesis to be wasted. In plants such as wheat and soybeans, enzyme reactions associated with photorespiration can cause plants to waste between 20% and 50% of their energy, according to the researchers.
The study, published on Thursday in Plant Biotechnology Journal was conducted as part of Realizing Increased Photosynthetic Efficiency (RIPE), an international research project that seeks to increase global food productivity in a sustainable way.
The team engineered tobacco to overexpress a native protein called the H-protein, which plays a role in plants’ recycling process, known as photorespiration. Based on two years of field trials, they found that increasing the amount of H-protein in the plants’ leaves led to crop production increases of between 27% and 47%.
Although previous research had experimented with increasing H-protein levels in plants in the lab, the new study is the first to examine the H-protein in a crop in real-world growing conditions.
“Plant scientists have traditionally used promoters that express proteins at high levels throughout the plant, and there are many examples where this has worked really well,” lead author Patricia Lopez-Calcagno, a senior research officer at the University of Essex, said in a statement. “But for the H-protein, we showed that more is not always better.”
Researchers found that increasing H-protein levels throughout the tobacco plant rather than in just the leaves had harmful effects, including stunted growth and reduced metabolism. These effects resulted in plants that at four weeks old were half the size of the plants that had not been genetically altered.
The findings demonstrate “that when we translate this method to other crop plants, we will need to tune the changes in protein to the right levels in the right tissues,” Lopez-Calcagno explained.
If researchers prove a genetic modification to be effective in tobacco, “the same approach can be applied to food crops that are needed to feed our growing population,” according to the study’s authors.
The team emphasised the importance of finding a solution to global warming-related crop stress.
“The reality is that as growing season temperatures continue to increase, the yield hit caused by photorespiration will also increase,” said study co-author Paul South, from the Carl R. Woese Institute for Genomic Biology at the University of Illinois. “If we can translate this discovery to food crops, we can equip farmers with resilient plants capable of producing more food despite increasing temperature stress.”
The team is planning to conduct additional research to increase H-protein levels in crops such as soybeans, cowpeas (also known as black-eyed peas) and cassava with the goal of increasing yields and creating opportunities for farmers.
The researchers also plan to combine the trait with other successful traits developed by the RIPE project to obtain even higher yields. By doing so, “we can make the yield gains needed to feed this century’s growing population,” said Christine Raines, a professor of plant molecular physiology at Essex.