Could quinoa solve worldwide food shortages?
The Incas called it the 'Mother Grain', while middle class residents of Cambridge and probably Camden call it lunch. But for many the quinoa plant - or Chenopodium Quinoa to give it its proper name - which can tolerate extremes of salt, and drought, and temperature and yet still produce nutritious seeds could be a future lifeline. Now scientists have decoded its genome to reveal where this extraordinary crop came from and how it can handle such harsh conditions. The ultimate goal is going to be to breed these traits into other quinoa strains and even completely different crop plants in order to combat concerns for future food security. Georgia Mills spoke to Mark Tester who led the work at the King Abdullah University of Science and Technology in Saudi Arabia...
Mark - About a third of the world’s food is produced under irrigation and a large fraction of the water sources that are being used for the irrigation are being depleted. We’re mining a lot of the world’s water and as the water is depleted so the quality of the water degrades, and it gets saltier. So we’re actually facing a very big challenge in global agriculture because a lot of the systems that are producing food at very high amounts at the moment are not sustainable. We need to be able to increase the salinity tolerance of crops in those systems.
Georgia - The amount of water is going down and, I suppose, at the same time the number of people and mouths to feed is on the up?
Mark - Yes. There’s an increase in demand for global food production. The UN Food Agriculture Organisation predicts that we will need at least 50 percent more food by 2050. And yet, one of the major systems of producing food at the moment is threatened with decreasing production, not increasing production.
Georgia - So quinoa, as a salt tolerant plant, suddenly looks quite important. Using several cutting edge sequencing technologies, Mark and the term worked out the most complete genome of the plant yet. But so what?
Mark - When you’ve got the genome sequence you can do a lot of things. You can have fun, and do things like understand some of the evolutionary processes that have led to the genomes being the way they are. But on a more applied level, once you have the genome then you can then start to look at differences in the genome between different individuals within the species. What we find often is that if you look at a large enough number of individuals and then you characterise those individuals: look at their salinity tolerance, the way they grow, the way they produce their flowers and so on. All the traits which are important to lead to a crop that we can harvest. And you can quantify each of those aspects of the plant and then look at all of their genomes and then what you can do is associate bits of the genome with particular traits and, with that, you can start to discover genes very, very rapidly. That’s what Sandra and the team did with the saponins.
Georgia - Saponins are a thorn in the side of quinoa growers. The plant creates these bitter compounds to protect itself, but it means that to wash away this bitter taste we need to use a lot of water which drives up the price. But now, knowing the genome the team have linked the production of these saponins to a specific gene which could make breeding sweet, cheap quinoa much, much easier. As post-doc researcher Sandra Schmoeckel explained…
Sandra - Saponins are only really harmful in the seeds or around the seeds. So you need to plant a plant, wait for it to grow and produce seeds and then you look at the seeds. So when you do your natural breeding and you’re looking for the sweetness now we have a marker. We know which gene is making it sweet so we can look at a plant and when it’s very little, tiny we can take a little piece of the leaf and look for it’s sweetness. That’s the major advantage of having the genome and knowing what genes are contributing to sweetness because we can look at them a lot earlier than conventional breeding.