Inserting a human RNA demethylase protein into plant genes can increase rice and potato production and improve drought tolerance.
Since the 18th century, experts like Thomas Malthus have projected that food production will not be able to keep up with the growth of the human population. True enough, with today’s rapidly growing population and increasingly unstable climate, food insecurity has become a major global concern, affecting around 957 million people or approximately 12 per cent of the world population this year, according to the United Nations’ Hunger Map.
Given its importance, scientists have been exploring ways to boost food supply by increasing crop production and agricultural yield. Yet most of the efforts to date have only resulted in minor improvements, thus demonstrating just how complex crop systems can be.
Fortunately, manipulating plant RNA has been found to help plants dramatically increase yield and drought tolerance, as demonstrated by a group of scientists from the University of Chicago, Peking University, and Guizhou University. Preliminary field tests have revealed that adding a gene that encodes for a protein known as FTO to rice and potato plants can increase their size, yield, and drought tolerance. The team is hopeful that this breakthrough can boost crop production in the face of climate change and other pressures that threaten crop systems.
Their journey to discovery first began in 2011, when He’s lab was studying gene expression in mammals. They found that cells can regulate gene expression by placing chemical markers onto RNAs to modulate protein production. These chemical makers can be erased by specific proteins, one of which is the human RNA demethylase FTO protein. The scientists established that FTO can target RNA to influence cell growth in animals and humans, and with that in mind, the team tried to insert the FTO gene into rice plants as an experiment to assess whether plant growth could be affected as well. The results were astonishing.
The rice plants with FTO genes reportedly grew three times more rice under greenhouse or laboratory conditions. When field tests were conducted, their findings revealed that the transgenic plants could increase biomass and yield by approximately 50 per cent. The presence of FTO was found to promote the growth of longer root systems by stimulating root meristem cell proliferation and tiller bud formation. FTO also boosted photosynthetic efficiency and raised drought tolerance. Additionally, when they repeated the experiments with potato plants, they observed similar results, demonstrating the gene’s potent universality.
"The change really is dramatic," said University of Chicago Professor Chuan He, who worked with Professor Guifang Jia at Peking University to lead the research. "What's more, it worked with almost every type of plant we tried it with so far, and it's a very simple modification to make."
Simple is not a word that can be used to describe the mechanisms underlying these remarkable effects. It was only after a series of additional studies that the scientists finally began to understand how FTO can boost crop yield so effectively. Their results suggested that FTO proteins can erase an RNA modification known as N6-methyladenosine, thereby muffling the signals that usually trigger plants to stop growing. Akin to removing all the red lights and leaving all the green lights turned on, plants can continue growing as more proteins are continuously translated. This theory is supported by the fact that modified plants produced significantly more RNAs than control plants.
"This really provides the possibility of engineering plants to potentially improve the ecosystem as global warming proceeds," said He, who is the John T. Wilson Distinguished Service Professor of Chemistry, Biochemistry and Molecular Biology. "We rely on plants for many, many things–everything from wood, food, and medicine, to flowers and oil–and this potentially offers a way to increase the stock material we can get from most plants."
Rice and potatoes are only the beginning. Once scientists are able to gain a complete picture of how FTO regulates plant growth, they hope to utilise this mechanism to innovate beyond food crops.
"Even beyond food, there are other consequences of climate change," said He. "Perhaps we could engineer grasses in threatened areas that can withstand drought. Perhaps we could teach a tree in the Midwest to grow longer roots, so that it's less likely to be toppled during strong storms. There are so many potential applications."
Source: Yu et al. (2021). RNA demethylation increases the yield and biomass of rice and potato plants in field trials. Nature Biotechnology.