As the global population continues to grow at an unprecedented rate, there will be 9 billion hungry people on the planet by the year 2050. To ensure this growing number of mouths are fed, the yields of key crops such as rice, wheat and maize must increase by 50% within the next three decades. A major obstacle in the way of this essential crop yield increase is the changing climate, as rising global temperatures has meant seasonal periods of heat stress are becoming more common, whilst water supplies are becoming heavily depleted. These environmental stresses are disrupting the growth of crops around the world and causing record levels of yield loss. Of course, this is not a new problem, and scientists have been working tirelessly for the last few decades, using all the tricks biology has to offer, to improve the stress tolerance and yield of crop species, from sweet potato to soybean. Some scientists have opted to use “conventional” techniques, breeding crop varieties with their ancient ancestors to improve yield and stress tolerance, whilst others have used techniques, similar to those used by a certain Doctor Frankenstein, to tackle the same problems. These somewhat Frankensteinian techniques have involved transferring genes from other plants, or sometimes genes from bacteria and animals, into crop species as part of an approach called “transgenics”. Although the use of transgenics is controversial, with only two transgenic crop varieties ever being approved to be grown commercially in the EU, the approach has led to the production of some high-yielding and stress-tolerant crop varieties that are perfectly safe to cultivate and consume. The latest addition to this list of superior transgenic crop varieties comes from the research laboratory of Professor Chuan He, the John T. Wilson Distinguished Service Professor of Chemistry, Biochemistry and Molecular Biology at the University of Chicago.
Professor He claims, in a paper published in the journal “Nature Biotechnology”, that scientists in his laboratory have produced potato and rice plants which show increased yields, higher levels of drought tolerance and longer roots. But how did they do this? They inserted a human gene, called “FTO”, into these plants. In humans, FTO is a key enzyme involved in the removal of a chemical mark, called “m6a”, from RNA molecules. The m6a mark is dynamically written, read and erased by various enzymes to regulate how RNA molecules are processed and metabolised. How RNA is processed determines how much of the molecule’s corresponding protein is synthesised, and subsequently has a dramatic effect on the cellular landscape, which can translate to whole-organism effects. He had known about the effects of manipulating levels of the m6a RNA mark in animal cells since 2011, however had never attempted to test the effect that this manipulation would have on plants. This was because plants have no FTO enzyme of their own and so manipulating levels of the m6a RNA mark would be difficult to achieve using conventional approaches such as breeding. However, in the paper published on the 22nd of July 2021, He reports how m6a RNA marks were manipulated in rice and potato plants, via transgenic insertion of the human FTO gene. Despite these exciting results, the Professor is aware of how controversial this approach may be, and thinks there may be other ways to achieve the same results, stating that “it seems that plants already have this layer of regulation, and all we did is tap into it. So, the next step would be to discover how to do it using the plant’s existing genetics”.
In its current form, the technology increases plant growth and yield by increasing the levels of RNA in cells and removing the m6a mark from RNA, using the human FTO enzyme. The m6a mark acts a signal to limit growth, therefore removing these marks removes this signal; allowing plants to grow larger and produce more harvestable yield. This research was speculative, as inserting human genes into plants can often yield unpredictable results, as the researchers noted in the paper – referring to how the human protein may be recognised as “foreign”, or even have effects on other molecules besides the RNA target. However, the researchers saw no such adverse effects, which marked the point where He started to believe his research group had made a significant breakthrough, stating “I think right then was when all of us realized were doing something special”. These “special” findings continued, as He’s transgenic rice showed a 300% increase in yield under laboratory conditions, and a 50% yield increase under field conditions, whilst also growing longer roots and being more tolerant of drought stress. The scientists were not content with these findings, however, pushing forward with their research to see if the same growth patterns would be replicated in an entirely different plant family – potato. Amazingly, the transgenic potato plants, containing the human FTO gene, also showed increased yield and drought tolerance. Observing identical growth patterns in completely unrelated plant species is very uncommon, and suggests the same transgenic approach could be taken to improve the yield and stress tolerance of many other crops, something He described as “extremely exciting”.
The researchers behind this breakthrough are hopeful about its potential to combat the pressures of climate change on global food systems and crop production worldwide. Nobel prize winners have also weighed-in to praise Professor He’s latest breakthrough, “this is a very exciting technology and could potentially help address problems of poverty and food insecurity at a global scale – and could also potentially be useful in responding to climate change” stated Michael Kremer, who was awarded a noble prize in 2019 for his work on alleviating global poverty.
So, what’s next for Professor He and his transgenic crops? He has stated his desire to work with academia and industry to further understand the biology behind this breakthrough, and how best to safely and widely apply this new technology. The Professor also has aspirations to use the transgenic technology in non-food plants, stating “Even beyond food there are consequences of climate change. Perhaps we could engineer grasses in threatened areas that can withstand drought. Perhaps we could teach a tree in the Midwest (USA) to grow longer roots, so that it’s less likely to be toppled during strong storms. There are so many potential applications”. Whatever comes next for these transgenic plants, it is clear that this breakthrough holds great potential to tackle the climate crisis and protect future crops. Who knows, in 30 years’ time Professor He’s crops may be grown all over the world, helping to feed 9 billion hungry people in the face of a changing climate.
Quotes from Professor He can be found here.