Gene manipulation using algae could grow more crops with less water

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Tobacco plants have been modified with a protein found in algae to improve their photosynthesis and increase growth, while using less water, in a new advance that could point the way to higher-yielding crops in a drought-afflicted future.

The technique focuses on photosynthesis, the complex process by which plants are able to use sunlight and carbon dioxide to produce nutrients that fuel their growth. Enhancing photosynthesis would produce huge benefits to agricultural productivity, but the complexities of the process have stymied many past attempts to harness it.

In research published in the journal Nature Plants, scientists used genetic manipulation processes to increase an enzyme that already exists within the tobacco plant, introduce a new enzyme from cyanobacteria, and to introduce a protein from algae.

When the plants were modified in this way, their ability to convert light energy efficiently into chemical energy increased significantly. To the surprise of the researchers, the transgenic plants also needed much less water to produce the higher yields.

Having proved the concept in tobacco plants, the scientists, at the University of Essex in Colchester in the UK, hope to further refine the technique and adapt it to crops, targeting soybeans, cowpea and rice. The development could help to ease some of the pressures the world is facing, in the climate crisis and the need to grow food more efficiently.

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 problem of how to increase photosynthesis was a core scientific goal, added Christine Raines, a professor of plant biology at Essex University and another of the paper’s authors. “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.”

Solving the same problem by using conventional plant breeding techniques might eventually be possible, said Lopez-Calcagno, but would take many decades. By introducing a gene from algae, the researchers were able to take a shortcut that was not available to nature, she said.

While GM crops are subject to an effective ban in Europe, the dangers that some people have perceived in genetic modification were quite different from the sort of genetic manipulation that has been used in creating the enhanced photosynthesis that the Essex team achieved, 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 was publicly funded, including by the Department for International Development, and any resulting developments will be made available to developing countries for free or at no profit. “The people who need it will be able to access it,” said Lopez-Calcagno.

The Essex research began in 2013, and it is likely to take another five to 10 years of development to get to the point of growing crops that use the technique.

Algae has shown promise for other uses of photosynthesis, including capturing and storing carbon dioxide. Research labs are working on using algae as a biofuel, as a food, and as an additive that could cut methane emissions from livestock.

A brief history of GM in Europe during the 21st century

Techniques for manipulating genes in plants, and animals, have developed swiftly in the last three decades, while the regulations surrounding the techniques in Europe have remained largely static. Many scientists believe that the time has come for a rethink on how we view and use GM techniques.

GM crops have been almost entirely banned in the EU since a moratorium in 1999, followed by a directive in 2001. Only one form of GM maize is currently grown in EU member states (mostly Spain and Portugal), although there are about 60 crops that are approved for use within the bloc.

One of the spurs to EU regulation was the attempt to introduce a fish gene into tomatoes, which a company in the US tried as a way of taking the anti-freeze gene that allows flounder to live in icy seas, splicing it into tomatoes to make them more resistant to cold. That research itself floundered, but the impression of “Frankenfoods” stuck.

However, modern transgenic techniques involve far less outlandish manipulation, usually involving minor variations in genetic material from similar species. The work reported from Essex University on Monday is an example: proteins from algae were introduced into tobacco plants, with the effect of enhancing the plant’s photosynthetic capabilities. Higher plants do not possess the required proteins.

Some scientists had also hoped that a new technique called gene editing could be used despite the EU’s strict rules. Gene editing involves manipulating the genetic material of a plant or animal species, without adding genes from other organisms – a form of rewriting the DNA from within, and thus different from transgenesis and other forms of genetic manipulation. Those hopes were dashed in July 2018, when the European court of justice ruled that gene editing fell under the same rules as other forms of GM.

Gene editing alone will not hold all the answers. Prof Christine Raines, one of the scientists involved in the Essex research, said a future goal was to use gene editing of proteins that exist within the target crops, but that is some way off, so the GM approach was needed in this respect.

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.”

In the UK, there are signs of a possible change in regulation after Brexit. Boris Johnson used his first speech as prime minister last summer to call to “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.”

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