Seanna Hewitt didn’t always care for pears. The ones she picked up at the supermarket were often unpredictable, overripe, or hard as a rock.

But as a doctoral student interested in food sustainability, Hewitt (’19 PhD Molecular Plant Sci.) was reacquainted with the fruit and joined the Washington State University Genomics Lab in its pursuit of a more perfect pear.

Seanna Hewitt
Seanna Hewitt (Courtesy WSU Three Minute Thesis)

When Amit Dhingra, now a professor and head of the department of horticulture at Texas A&M and adjunct professor at WSU, launched the lab about 15 years ago, he recalls how many researchers were trying to solve the pear ripening problem through the lens of apples.

“Initially, pears weren’t even on my radar,” he says. “A farmer, Chuck Peters, reached out to me and said, ‘I hope you’ll work on pears.’”

As Dhingra met with growers across the country, he heard a similar sentiment about the need for new knowledge and tools for the pear industry. In turn, the lab set out to sequence the pear genome and explore the inner workings of fruit.

Pears don’t typically ripen on the tree. Instead, they spend time in cold storage which kickstarts the production of a ripening molecule: ethylene.

People who put unripe fruit in a brown paper bag also take advantage of this molecule. The ethylene released from the fruit gets concentrated in the bag and speeds up the ripening process.

In packing houses, pears are often treated with ethylene after their cold spell. But in recent years Dhingra, Hewitt, and fellow WSU researchers have discovered there’s more to it than just ethylene.

When Hewitt joined the lab in 2014, she began to investigate the molecules and molecular pathways that might promote ripening, specifically in D’Anjou pears. Along with Bartlett and Bosc, D’Anjous are among the top varieties grown in the Pacific Northwest.

The compounds and molecular pathways she identified, along with those identified by her predecessors in the lab, hold potential as targets the industry could use for regulation⁠—turning genes on and off to improve the fruit’s quality⁠—and fine-tune ripening.

For instance, producers who treat pears with a compound called 1-MCP, which slows or in some cases completely blocks ripening at harvest, could ship the fruit to its destination. Then they could apply a compound like glyoxylic acid, which can overcome 1-MCP, and restart ripening as needed.

“If we can solve the ripening problem in pears, we can do it in almost any fruit,” Hewitt says.

Understanding these nuances at the molecular level could help improve food sustainability, reduce food waste from consumers, and even prevent losses that often occur before harvest.

The discoveries also bring new ideas to Washington state’s $250 million pear industry. Fresh sliced pears, for instance.

“That’s the ticket,” Dhingra says. “If you slice it and sell it, a ten-cent pear is now worth a dollar and ten cents. There’s so much margin to be made in the industry.”

In partnership with the WSU School of Biological Systems Engineering and with funding from the Washington State Department of Agriculture, the lab is now developing packaging that’s just right for fresh sliced pears and the ripening research continues.

Meanwhile, Hewitt is now working as a scientist in the horticulture industry and sees the fruit in a different light⁠—full of potential and promise, in many ways, thanks to basic research inspired by growers. As she puts it, “There’s still hope for the pear.”