Can CRISPR keep the beer flowing?

A staple crop around the world, barley is grown for animal feed, breads and cereals, and, most crucially of all, as malt for making beer and whiskey. 

But a warmer world is posing problems for this essential brew ingredient. Fortunately, CRISPR and clever scientists have found a way to keep the malt flowing. 

The problem: Barley can suffer from “pre-harvest sprouting,” where the grain sprouts before it can be harvested. Prematurely sprouted barley is less useful and less valuable on the market, damaging farmer’s bottom lines — and climate change stands to exacerbate the problem, as warmth and unexpected rain can kick off the early sprout.

Barley’s been domesticated since, oh, 8,000 BC, and it’d be a shame if we dropped the ball now. And, as New Atlas reports, researchers have known for a while how to use genetic engineering to keep barley dormant and prevent premature sprouting — but the current methods also harm its ability to be used for malt.

A warming world is posing problems for barley, an essential ingredient for breads, cereals, and beer.

Since we obviously cannot have the world’s beer and whiskey supply imperiled, researchers at Japan’s Okayama University are turning to CRISPR to create better, more resilient varieties of barley. 

“We recognized the need to strategically manipulate crops to weather the effects of steadily exacerbating climate change,” research team leader Hiroshi Hisano, an associate professor at Okayama’s Institute of Plant Science and Resources, said. 

His team already has expertise in precision editing of the barley genome, and previous studies have identified two genes that are key to the grain’s dormancy.

“Hence, our modus operandi was pretty clear.”

A self-inflicted wound: Barley’s not wholly defenseless when it comes to sprouting. Like most cereals, barley can sense the best time to sprout and close up (or go dormant) when conditions aren’t right.

“Grains exhibit dormancy to prevent sprouting under adverse conditions and environments and only germinate when favourable conditions return,” the researchers wrote in their study, published in Plant Biotechnology Journal. 

Human plant breeders have reduced barley’s dormancy time so that we can harvest it multiple times in a season, but we also must reap what we’ve sown.

“This brevity of dormancy can cause pre-harvest sprouting in some temperate areas where the crop harvesting season coincides with high humidity,” the researchers wrote.

Bettering barley: To help prevent this, the Okayama team set their sights on two genes (called qsd1 and qsd2, for you geneticists). These genes each impact barley’s dormancy, or its ability to hang around without sprouting.

Using CRISPR-Cas9, Hisano and his team caused specific single and double mutations — known as “targeted mutagenesis” — in these genes of Golden Promise barley. All of the resulting plants kept sprouting at bay, but different mutations and different conditions impacted the results.

“We could successfully produce mutant barley that was resistant to pre-harvest sprouting, using the CRISPR/Cas9 technology.”

Hiroshi Hisano

“We could successfully produce mutant barley that was resistant to pre-harvest sprouting, using the CRISPR/Cas9 technology,” Hisano said.

 However, all of the mutant varieties sprouted when exposed to cold temperatures, which the researchers say is a sign that their dormancy genes were merely, well, dormant, not turned off — which is important because we do need the barley to sprout eventually.

“The motivation for this study was fuelled by the need to fine-tune barley grain dormancy for breeding,” the researchers wrote, finding the correct balance tolerance and the uniform sprouting eventually needed to create the best beer.

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