Tobacco plants have been engineered to improve their photosynthesis and increase growth with a protein found in algae, while using less water, in a recent development that may pave the way to higher yielding crops in a drought-afflicted future.
The technique focuses on photosynthesis, the complex process through which plants can use sunlight and carbon dioxide to produce nutrients which fuel their growth. Improving photosynthesis can yield tremendous benefits for agricultural production, but many previous attempts to exploit it have been stymied by the complexities of the process.
Scientists used genetic engineering processes in work published in the journal Nature Plants to increase an enzyme that already exists inside the tobacco plant, add a new enzyme from cyanobacteria and add a protein from algae.
When the plants were thus changed their ability to efficiently transform light energy into chemical energy increased significantly. To the researchers’ surprise, transgenic plants also required much less water to achieve the higher yields.
The scientists at the University of Essex in Colchester in the UK, having proved the principle in tobacco plants, hope to further develop the technique and apply it to crops, targeting soybeans, cowpea and rice. Technology may help ease some of the world’s stresses in the climate crisis, and the need to develop food more effectively.
Patricia Lopez-Calcagno, a co-author of the paper, said: “The global population is increasing, and that means we need to grow more food. We are also seeing the effects of climate change, creating more extreme weather, so we will have more droughts. That means we are going to need to make better use of water. We need more crops from the same amount of land, and with less water.”
Cracking the question of how to improve photosynthesis was a key scientific goal, added Christine Raines, a professor of plant biology at the University of Essex and another author of the paper. “This is the most fundamental process on Earth – without photosynthesis there would be nothing,” she said. “All the food we eat, the plants and the food our animals eat, comes from this primary process. We understand a lot about it, but it involves a huge number of individual steps.”
It could eventually be possible to solve the same problem by using traditional breeding techniques for plants, Lopez-Calcagno said, but it would take several decades. The researchers were able to take a shortcut by adding a gene from algae that was not available to nature, she said.
Although GM crops are subject to an effective ban in Europe, the dangers feared by some people during genetic modification were very different from the kind of genetic engineering used to produce the enhanced photosynthesis achieved by the Essex team, she said.
“I do not think there is anything to worry about from this,” Lopez-Calcagno said. “GM has had a really bad press as it was associated with big corporations taking power away from farmers, and with the overuse of herbicides. But that is not the case here.”
The research has been publicly funded, including by the Department for International Development, and any subsequent advances will be made available free of charge or at no fee to developing countries. “The people who need it will be able to access it,” said Lopez-Calcagno.
Research into Essex started in 2013, and it is likely to take another five to 10 years of growth to get to the point of growing crops using the technique. Algae has shown potential for many photosynthesis applications, including carbon dioxide capture and storage. Research laboratories are focusing on using algae as a biofuel, as a supplement and as an additive that could minimize livestock methane emissions.
In the last three decades, techniques for manipulating genes in plants and animals have evolved rapidly, while the regulations governing the techniques in Europe have remained largely static. Many researchers believe the time has come to reconsider how we interpret and use GM techniques.
Since a moratorium in 1999, GM crops have been almost completely banned in the EU, followed by a Directive in 2001. Only one type of GM maize is currently grown in EU Member States (mostly Spain and Portugal), although there are approved for use in the block about 60 crops.
One of the spurs to EU control was the effort to incorporate a fish gene into tomatoes, which was attempted by a US corporation as a way to take the anti-freeze gene that helps flounder to survive in frozen seas, slicing it into tomatoes to make them more cold-resistant. That work itself was floundering, but the “Frankenfoods” idea has stuck.
Modern transgenic methods, however, require much less outlandish modification, typically involving minor genetic material changes from related species. The research published on Monday from Essex University is an example: algae proteins were introduced into tobacco plants, with the effect of increasing the photosynthetic capabilities of the plant. Higher plants don’t have the proteins they need. Some scientists also had hoped that given the strict EU guidelines, a new technique called gene editing could be used.
Gene editing includes altering a plant or animal species’ genetic material without inserting genes from other organisms – a form of DNA rewriting from inside, and thus distinct from transgenesis and other types of genetic engineering. In July 2018, when the European Court of Justice ruled that gene editing falls under the same rules as other forms of GM, those expectations were dashed.
Gene editing alone isn’t going to hold all the answers. Prof. Christine Raines, one of the scientists involved in Essex study, said that a potential aim was to use gene editing of proteins that occur inside the target crops, but that’s some distance away, so the GM approach was required in this regard.
Prof Wendy Harwood of the John Innes Centre said: “There are a lot of new techniques available, and we need all of them, really – we can’t just rely on one. We need the best technology for the outcome.”
There are signs in the UK of a potential regulatory reform following Brexit. Last summer, Boris Johnson used his first speech as Prime Minister to call for “liberate the UK’s extraordinary bioscience sector from anti-genetic modification rules and let’s develop the blight-resistant crops that will feed the world.”
Prof Dale Sanders, the director of the John Innes Centre, said: “An approach to regulation based on what is produced rather than on technologies used to deliver the product would be very sensible.”
