THE PLANT WHISPERER
A famine crisis is looming. Stephen Long’s work aims to feed the masses by supercharging the plants we eat
“The UN Food and Agriculture Organization says that we’re going to need 70 per cent more food by 2050. With current rates of crop improvement we’re not going to get there”
In the middle of the 20th Century, many parts of the world were on the brink of famine. A growing global population was butting up against the limits of food supply, with disastrous consequences. But the lives of more than a billion people were saved by a ‘Green Revolution’ – the spread of techniques like irrigation, hybridised seeds, and human-made fertilisers and pesticides from industrialised countries to the developing world.
Today, we’re facing a similar crisis. “The UN Food and Agriculture Organization says that we’re going to need 70 per cent more food by 2050, and with current rates of crop improvement we’re not going to get there,” says Stephen Long, director of The RIPE Project, which aims to spur a second Green Revolution by engineering crops so that they’re able to photosynthesise more efficiently.
“Photosynthesis is the process that converts sunlight energy and carbon dioxide into the substance of a plant, so it’s basically the source, directly or indirectly, of all of our food. We know that in crop plants this process is not actually very efficient, and we now understand enough about the process that we can start to intervene and genetically improve its efficiency.”
Historically, prevailing wisdom has always been that photosynthesis couldn’t be made more efficient. After all, why would evolution have not optimised such an important process? But Long points out that evolution optimises for survival and reproduction, not maximum output of the seeds and fruits that humans eat.
Meanwhile, we’re living in a different environment from the time of the first Green Revolution. “A major molecule involved in photosynthesis is carbon dioxide, and in the last 50 years, through our activities, we’ve increased the concentration of carbon dioxide in the atmosphere by 25 per cent. That is a very short time for evolution to adapt to a change,” says Long.
So, he and his team set to work proving that it was possible to boost the efficiency of photosynthesis. With funding from the Bill and Melinda Gates Foundation, they started tinkering with tobacco – a plant that’s relatively easy to engineer. To begin with, his team transferred genes from Arabidopsis thaliana, better known as thale cress, to the tobacco plant in the hope of helping it shed heat energy more efficiently. When three variants of these engineered plants were grown, their yields were 13.5 per cent, 19 per cent and 20 per cent greater than normal tobacco plants grown as a comparison. “Although we understand photosynthesis now in plants in great detail, it is a complex process. It’s over 160 discrete steps. The first part of the project was actually simulating the whole thing on a computer. We could then try billions of manipulations, mathematically, to then see where might be the best places to intervene.”
What’s more, these impressive gains were achieved with minimal increases in resource costs. The engineered plants required about 1 to 2 per cent more nitrogen than the unmodified plants, and no increase in water use. “That is really the beauty of improving photosynthetic efficiency,” says Long. “It’s not only the efficiency with which they use light, but it’s also the efficiency with which they use water and nitrogen. So in most cases, we are getting more productivity for the same amount of water, and minimal increases in nitrogen.”
The big question is whether these gains in tobacco can be transferred to food crops, and there’s reason to believe that they can. Photosynthesis works in the same way in tobacco as it does in many food crops, and tests are planned to see if similar modifications can deliver increases in yields of staples like rice, cowpeas and cassava. The potential is enormous, but the clock’s ticking. “Any innovation we have today is going to take about 20 years to be available to farmers at the scale we need,” says Long. “So while 2050 might sound a long way off, in terms of improving crop productivity it’s quite close.”