The end of fire blight in Adams County?

Sixteen first-year Gettysburg College students gather in a semicircle in the middle of an orchard. It’s their first day of college classes, but they’re not there to pick apples for their new professor. They’re there to hunt phage, although they don’t know what that is yet.

Phages course

Prof. Nikki Shariat introduces Kari Peter, Assistant Professor of Plant Pathology from the Penn State Fruit Research and Extension Center in Biglerville, PA and Dave Wenk, owner of Three Springs Fruit Farm and the orchard where they’re standing.  Wenk cuts off a branch from one of the apple trees.  Brown leaves curl in tendrils, dry and dead. The apple oozes. “Ten years ago we didn’t know what fire blight was,” he says.

Phages course

Fire blight, Peter explains, is a bacterial disease that damages fruit trees and related plants, including apple trees. In 2014, growers like Wenk lost between $1,000 and $20,000 per acre as a result of fire blight. That kind of impact is devastating, especially in Pennsylvania, which is the fourth largest producer of apples in the country. And 75 percent of those apples come from Adams County, where Gettysburg is located.

Fire blightBut what does fire blight have to do with phage? What is phage, and why are these students hunting it?

Fire blight is caused by the bacterium Erwinia amylovora. A bacteriophage—phage for short—is a virus that infects and replicates within a bacterium (like E. amylovora). As part of the yearlong Introduction to Phage Biology course taught by Shariat, these students will look for—hunt—the phage found naturally in the orchard. The idea is that if you can harness the power of the phage to do what they already do—attack E. amylovora—then you can use it to eradicate the bacteria and put an end to fire blight.

Before joining the faculty at Gettysburg College this year, Shariat completed a postdoc at Penn State, so she knew about the significance of the apple industry in the state. It was during her interview when she presented the idea that would turn into the focus of the phage course: “I thought, wouldn’t it be great if we can identify phage against this bacteria and then use it as a potential therapy,” she says. “And so I’ve been in connection with Dr. Peter and she’s educated me on how terrible fire blight is for our growers.”

Partnerships are an important component of the course. In addition to working with local growers and the Fruit Research and Extension Center at Penn State, Shariat and her students are collaborating with Brigham Young University (BYU), where researchers are also investigating how to use phage therapy against fire blight and have previously found success in treating honeybee-killing bacteria.

“Part of the benefit of students completing the phage class is not only the research experience, but also being able to take ownership of a research project and feel like they are part of a research community,” says Shariat. “Students learn by doing, by communicating their findings and by being part of a research team.”

Which is why, she says, Gettysburg College will sponsor a trip that will allow all sixteen of her students to travel to BYU for a symposium in April.  There, every student will have the opportunity to share the culmination of their research and findings with one another. The two classes will also collaborate throughout the year remotely via web conference and mini-projects. For example, over the winter, Gettysburg will send samples to BYU’s lab, where they will sequence the phage’s DNA. In the spring, students will assemble genomes and study their genetic makeup, comparing the similarities and differences between BYU and Gettysburg phage. This will help them learn more about how to optimize phage therapy by location, applying what they learn to create the ideal conditions for phage to fight fire blight in Adams County.

“It’s great for the students to be able to have a research experience and give them ownership over their own project and the outcomes, but some of the skills they learn go way beyond the standard fundamental biological skills,” Shariat adds. “The number one lesson they learn is failure and how to deal with it. Some students had to try seven times before they got phage.”

Phages course

That’s why it’s called phage hunting. The process entails cutting the branch of the apple tree into tiny pieces, preparing a plate sample, and then incubating that plate. Because phage eat bacteria, finding phage requires finding the absence of the bacteria, called plaques, which appear as clear spheres that look like air bubbles. Often what the students find are air bubbles—finding phage requires perseverance.

Phages courseFor Jacob Marogi ’19, the process took over a month.

“It got to the point where I was having dreams about finally getting phage on my plates,” he jokes. “But even for those of us who took longer, we were still excited for our classmates who found it. We’re all contributing to the greater good.”

In many ways, the class operates as a team, mimicking the work of colleagues in a professional lab. All students are hunting their own phage but are working as part of a group research initiative. Marogi says he helps out classmates who can’t get to the lab when their samples need maintenance, and others return the favor.

To promote the team concept, in their second week of class, the students participated in a ropes course and team-building exercise organized by the Gettysburg Recreational Adventure Board (GRAB)

Dorothy Vosik ’19, another student taking the course, said having a long-term goal helps. “I know where we want to go and how this is going to help people in the future,” she says.  “I didn’t know what fire blight was before this class, and I didn’t know how it was affecting Pennsylvania, even though I’m from Pennsylvania—this research helps my home state and the people who own orchards in the county.”

Phages courseBut the research has broader implications as well.

In response to accounts of antibiotic resistance against diseases like MRSA and bacterial infections that cause problems like acne and staph infections, phage therapy provides an alternative, cost effective treatment. Phage therapy “cocktails” can be created to treat specific infections. When resistance develops, a new cocktail can be deployed. The treatment was first developed in the early 1900s and used mostly in Eastern Europe and Russia, where they still use it today.

Phages course

For now, Shariat and her students will continue to focus on using phage therapy in the fight against fire blight. For Wenk and Three Springs Farm, that means being able to focus on the business. For the students, it means being able to learn how to do research, work in a lab, and directly apply their coursework to solving a problem in the community—all in their first year (and days) of college.

And, according to Marogi’s own words, “that’s an experience not many students, let alone first-years, are getting across the country.”

Read more in The Evening Sun.

Gettysburg College course helps local farmers

The Gettysburg College freshmen gathered around a computer screen Wednesday to inspect the photograph of tiny gray splotches, exclaiming about the coolness of what they were seeing...

View photos on Flickr.


Founded in 1832, Gettysburg College is a highly selective four-year residential college of liberal arts and sciences with a strong academic tradition. Alumni include Rhodes Scholars, a Nobel laureate, and other distinguished scholars. The college enrolls 2,600 undergraduate students and is located on a 200-acre campus adjacent to the Gettysburg National Military Park in Pennsylvania.

Contact: Carina Sitkus, senior assistant director of communications, 717.337.6803

Posted: Mon, 16 Nov 2015

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