Across the world, strategic seed banks keep safe seeds that could replenish agriculture after a cataclysm. But they aren’t just for a worst-case scenario, writes Veronique Greenwood.
Imagine an eerie slice of concrete on a frozen northern isle, holding a vault of seeds against the end of the world. The words “seed bank”, might conjure up the so-called Doomsday Vault, on the island of Svalbard. There, collections of the world’s crops are held in stasis in case of future need, like a catastrophic volcanic eruption, a world war, or rapid sea level rise.
But what most people don’t fully comprehend is that the Vault is primarily a back-up, a very placid hard drive of genetic material from a kaleidoscope of far more active facilities all around the world. These gene banks are managed by foundations, universities and governments. In some circles, the World Vegetable Center in Taiwan is famed for the completeness of their aubergine collection. Peppers, too, are a specialty, and gene bank manager Maarten van Zonneveld has a particular yen for the mung bean.
More than 132,000 samples of rice varieties reside in the International Rice Genebank in the Philippines. Wheat and corn and their little-known wild relatives swell the storage facilities of the International Maize and Wheat Improvement Center not far from Mexico City. Other crops have their devotees, and their collections, dotted around the globe.
By and large, these resources are available to plant breeders looking to create better, hardier, or tastier crops. “The gene bank is part of open science,” says van Zonneveld. It’s there to serve.
But with the rise of large-scale genome sequencing, these repositories are starting to play a new role. If you want to know the evolutionary history of the chili pepper, or how to breed a chickpea that can survive climate change, the seed bank is an intriguing dataset to draw on. It’s not just for Doomsday. It’s for the day after tomorrow.
When you have information about a plant’s genetics, you can correlate its genes to its appearance, hardiness and other qualities. This makes it easier to choose promising parents for potential future varieties. It can also make it easier, once you have bred new plants and have a thousand twiggy saplings of apple, for instance, to pick the ones that are going to have the features you like the most. With a snip of leaf tissue, you can generate a sequence revealing which got their father’s cold hardiness as well as their mother’s convenient height for picking fruit, rather than having to grow and observe them for years. All the others go by the wayside.
‟ In this first batch alone, the team identified more than 1,600 genes in chickpeas that were new to science
In this context, a seed bank’s tens-of-thousands of samples, or accessions, as they are generally known, start to look like rich pickings for anyone trying to understand how crops tick. Rajeev Varshney, presently at Murdoch University in Australia, put a vast sequencing project in motion when he was at the International Crops Research Institute for the Semi-Arid Tropics in India. The seed bank there has more than 20,000 accessions of chickpeas and their relatives, as well as massive collections of millet and sorghum and other crops, some varieties of which have been wiped out in their original homelands.
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In the fall of last year, Varshney and his colleagues published full genomes of more than 3,300 accessions of chickpeas and their relatives, one of the largest crop genome sequencing efforts ever. That’s just the beginning, he says: “We had a plan to sequence all accessions… we have the data for another 10,000.” In this first batch alone, the team identified more than 1,600 genes in chickpeas that were new to science, which may provide leads on new ways to breed disease and climate change resistance into the crop. It helped sketch a family tree suggesting that chickpeas went through a period of unpopularity some thousand years ago; a relatively small number of plants from back then seem to be the ancestors of all living varieties.
In another big sequencing effort published in 2021, Pasquale Tripodi at CREA Research Centre for Vegetable and Ornamental Crops in Italy and colleagues sequenced snippets of DNA from more than 10,000 accessions of peppers. Comparing data from peppers held in five different seed banks, they created a family tree which allowed them to trace the long-ago movement of pepper varieties back and forth between Europe and Asia, presumably along trade routes.
Although this work sequenced only part of the peppers’ genomes, it allowed the researchers a glimpse into the plants’ history that would not have been possible without genetic technology.
As more and more research groups sequence the bounty that seed banks hold, we may uncover not only the hidden travels of these familiar crops and their wild relations, but the genes that might be our saving grace in times of climate uncertainty. The World Vegetable Center, like other seed banks, is making an effort to put genetic and other information in a format that crop breeders can easily browse, says van Zonneveld. “For many breeders, it’s a challenge to select from 10,000 accessions. Where do you start?” he says.
Instead, seed banks put together curated collections of just a few hundred accessions. These might be centred around a theme – plants tested and proven to thrive in a hydroponic farm set-up, plants that don’t blanch when salt water soaks their soil, or plants which handle drought well, for instance. Genetic information and detailed physical descriptions can be presented together. Then breeders who work for companies, universities, or other institutions can go shopping, in a sense, for the traits they are hoping to introduce to crops. It’s a way get an easy sense of what the banks have to offer.
They’re meant to be more than vaults, after all – they’re active repositories of what lives on the planet, on hand to produce what might live here in the future.
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