CRISPR tomatoes are at the forefront of a food revolution. No, this is not another Golden Fleece Award. It is a scientific project for here on earth that could help guarantee our food sources in the future.
At first glance, they look like any other plant that can be found growing in the corners of offices, or on the windowsills of university laboratories. But this particular tomato plant, grown in 2018 at the University of Minnesota, is different. The bushy tangle of elongated leaves and small red fruits are characteristic of a wild species of tomato plant native to Peru and Ecuador called Solanum pimpinellifolium. It’s also known as the red currant tomato. On closer inspection, however, this plant’s uniqueness becomes more apparent.
It is more compact, with fewer branches, but more fruits, than the wild tomato. Its fruits are also a little darker in color, a sign of increased lycopene; lycopene is an antioxidant linked to a lower risk of cancer and heart disease. It has been designed that way.
The plant was created by geneticist Tomas Cermak and his colleagues using CRISPR gene editing. This Nobel Prize-winning technology works like a “cut and paste” tool for genetic material. The technique is now revolutionizing agriculture and helping create crops for the future. Cermak himself is on a mission to find a perfect tomato, one that would be easy to cultivate, nutritious and tasty, yet be more adaptable to a changing climate. “The ideal plant would be resistant to all forms of stress — heat, cold, salt, drought, as well as pests,” he says.
Climate change spells trouble for many crops, and tomatoes are no exception. Tomatoes don’t like heat, growing best between 18C (64F) and 25C (77F). Cross either side of that threshold and things start going downhill rapidly: pollen doesn’t form properly and the flowers don’t form into berries in the way they should. On the higher end of the temperature scale, once the mercury goes over 35C (95F), yields begin to collapse. A 2020 study showed that by mid-21st Century, up to 66% of land in California historically used for growing tomatoes may no longer have temperatures appropriate for the crop. Other modelling studies suggest that by 2050 large swaths of land in Brazil, sub-Saharan Africa, India and Indonesia will also no longer have an optimal climate for cultivation of tomatoes.
That’s troubling because tomatoes are currently the largest horticultural crop in the world – humanity produces 182 million tons of the fruit every year, equivalent to the weight of almost 32 Great Pyramids of Giza. What’s more, our appetites for tomatoes are growing fast – over the last 15 years global production of tomatoes rose by more than 30%.
CRISPR gene editing is a molecular toolbox scientists have repurposed from bacteria. When bacteria are attacked by viruses, they capture and cut the viral DNA to prevent the aggressor from replicating, and so fight it off. In use in plants since 2013, CRISPR now allows researchers to modify genome with extreme precision and accuracy to obtain traits they desire. You can insert genes, delete them, and create targeted mutations. In non-human animals, CRISPR is being used for the study of human disease models, for improving livestock, and could even potentially be used to resurrect extinct species. In plants, it can help create better, tastier, more nutritious and more resistant crops.
Domesticating crops, tomatoes included, has led to a huge loss of genetic diversity. Modern commercial crops may be fast to grow and easy to harvest, but genetically speaking they are homogeneous. Just four highly homogenized crops – soybeans, rice, wheat and corn – dominate global agriculture, accounting for more than half of all the world’s agricultural land use. In contrast, their wild cousins are a treasure trove of genetic diversity. This is why scientists are now searching this wild genetic pool to identify traits that can be reintroduced into commercial plants. The fast-dropping costs of DNA-sequencing technologies is making this technique more commercially viable and, therefore, more readily available.
However, there is the law. Although in 2016 CRISPR-edited mushrooms fell into a legal loophole in the U.S., and escaped regulation, Europe’s highest court decided in 2018 that gene-edited crops should be subject to the same stringent regulations that govern conventional GM organisms. For Cermak’s climate-smart “ideal tomato”, such legal hurdles paired with consumer hesitance, could prove a major obstacle.
We obviously have to be very careful about the development and testing process, and each step needs to be thoroughly investigated, but the potential of CRISPR gene editing is both fascinating and encouraging.