Drought cuts down harvests every year, but new local research may allow farmers to maximize their output even as water becomes more scarce.
A team at the Salk Institute investigating plant aging has charted a new path to drought-tolerant crops. While the broader scientific community is packed with research on human aging, they have found plants approach the process very differently.
“Plants are able to accelerate their aging when undergoing environmental stress. If you and I don’t get enough water, not enough food, we’ll just die – we don’t have internal flexibility. Plants can say, ‘I don’t have enough resources. I’m going to speed up my aging process,’” said Joseph Swift, PhD, the first author of the Nature Plants study.
While the average person might scoff at choosing to age faster, plants see things differently. Aging faster actually helps them stay alive.
“Imagine you’re a plant, growing super happy and you have enough water. You’ve developed all these leaves and have grown to a certain level that you match how many resources you have. If you run out of water, you need a way to shrink your size really quickly,” said Swift. “They do that by throwing off leaves, so the older leaves start dying.”
Stress avoidance causes leaves to shrink in size and eventually wither away. Even if a plant looks perfectly healthy, it can still be dealing with stress. It was not known how exactly plants do this. Swift and his senior colleague, Joseph Ecker, PhD, sought to uncover this “magical property of plants.”
The pair turned to Arabidopsis thaliana, a fast-growing weed that botanists worldwide use as a model organism – it works like mice in human studies. The plant’s genetic code relates to a wide range of crops, including corn, wheat and rice.
They found a specific gene, FRO6, is turned off during drought conditions. Since it had the clearest connection to limiting leaf sizes, Swift and Ecker elected to genetically engineer the plant so this switch would always stay on.
By removing the ability to regulate growth, scientists can develop crops that perform at their best even under stress. Farmers often don’t know until the harvest if invisible drought stress is making their fields less productive.
If this kind of genetic edit is applied to crops, it would be the first proactive measure against these unseen stressors. Until then, farmers still will be stuck reacting after the damage has been done, surveying fields with tools like leaf scanners, satellite imagery and drones.
This does not mean fields will be full of freshly genetically modified crops – that will take time. The Salk Institute hopes its observational research lays the groundwork for future discoveries.
“We looked at drought in a way folks haven’t before,” said Swift. “In the face of climate change and limiting water resources, we need to move into a future with better technology to help agriculture be adaptive, both in this country and in other places.”
Juan Martinez has operated Heritage Family Farms since 2008. With a specialty in fruit trees, he offers in-season farm-to-table goods at local farmers’ markets. He limits how much he waters his plants, naturally adapting them to drought conditions and improving their resistance. He believes drought-tolerant crops would work wonders for his business.
“They wouldn’t slow down at any point, not even during the transition period from being under watered to when they have enough, like a wet winter,” said Martinez. “They have to adapt to less watering and essentially learn to survive again with less nourishing conditions. We wouldn’t see any decline in production; it would make me more money.”
Steven Briggs spent the first half of his career working on agriculture biotechnology. Today, the professor is focused on crop disease resistance and teaching the science of the genome at UC San Diego. In a world with a changing climate and agricultural economy, Briggs sees the promise of a future with drought-resistant crops.
“The primary impact will be to increase the income of farmers. Nobody’s going to pay more because this came from a drought-tolerant plant, but farmers will save money. Therefore, they’ll earn more and be willing to pay more for the seed,” said Briggs.
Water is not an issue in the current market, since farmers have access to affordable water from the Colorado River. But with disputes over the river’s water rights, Briggs foresees an increase in farmers’ costs that could be transferred to the consumer.
“I don’t think anything is going to cause prices to go down. Even beyond price, there’s only so much water. Agriculture takes about 80% to 90% of all of our fresh water across the country. So, as cities and consumers require more fresh water, it has to come from agriculture,” said Briggs.
Advances in developing drought tolerant crops could help San Diego farmers maintain their current level of production as water becomes more scarce and costs rise.
“You’re dependent on a farmer somewhere, being able to make enough food and to make affordable food. This is something we’ve taken for granted, but we’re entering a period where I think we’ll see a tipping point. Prices will go up dramatically, and in some cases, supplies won’t be adequate,” said Briggs.
