Engineering fungi to help plants fight disease – Author interview with Geoffrey Zahn

Last week we published Foliar microbiome transplants confer disease resistance in a critically-endangered plant by Geoffrey Zahn and Anthony Amend. Their study tested whether fungi could be engineered and employed to help plants respond to fight disease, thereby reducing dependence on harmful fungicide treatments. The plants which received applications of a simple leaf slurry containing an uncultured fungal community showed significant disease reduction. We interviewed Geoffrey Zahn about this research and its implications for understanding fungi-plant relations.

Can you tell us a bit about yourself?

GZ: I am a microbial ecologist based out of Utah Valley University. I study the functional roles of fungal and protist communities with an aim to better understand the drivers of microbial community dynamics and to address ecological goals.

View from some historic Phyllostegia kaalaensis habitat and the site of the new outplantings.

Can you briefly explain the research you published in PeerJ?

GZ: Fungi seem to live inside every leaf of every plant on earth. There’s a recently emerging perspective that these endophytic fungi help modify plant responses to disease. Our hypothesis was that we could try to engineer “good” communities of fungi to help a critically-endangered Hawai’ian plant from the mint family. These plants lived only in highly managed greenhouses, and were totally dependent on regular doses of fungicides to prevent them from dying.

Phyllostegia kaalaensis in bloom in a growth chamber. White patches are the fungal pathogen, Neoerysiphe galeopsidis

One problem with this fungicide-dependence is that plants aren’t so different from humans or other animals. . . when it comes to their health, every plant and animal depends on a host of mutualistic beneficial micro-organisms. The fungicides that prevented infection from bad fungi were also killing off potentially good fungi that the plants needed to survive in the wild. We found a simple and effective way of restoring some of these beneficial fungi to the plants before they were taken out into the wild.

Do you have any anecdotes about this research?

GZ: This project was part of my postdoc experience at the University of Hawaii with my mentor and co-author, Dr. Anthony Amend.  When I first got to the island, we hiked through the jungle for hours to go see the last remaining wild population of these endangered plants. But when we got there, all that was left were the flags marking where each individual had been placed. It was like a graveyard.

Hiking through the Phyllostegia graveyard, the previous “last stand” of wild P. kaalaensis before our study

It really hit home how perilous the position of these plant was. I sat there, having one of the most surreal lunches of my life. I had never felt such a personal connection with extinction before and I came away from the experience rather changed and determined to do what I could to help.

What kinds of lessons do you hope your readers take away from the research?

GZ: I think we need to stop treating plants as “just plants.” They are very complex organisms, engaged in a dizzying array of interactions with other organisms, including microbes. If we want to conserve endangered plants, or even increase agricultural efficiency, we need to step back and think about every aspect of the plants, including their microbiomes.

How did you first hear about PeerJ, and what persuaded you to submit to us?

I actually heard about PeerJ at a mycology conference my first year in graduate school and I was excited about the model, the low cost, and the focus on rigorousness as opposed to novelty. I published my first dissertation chapter in PeerJ and had such a great experience that I keep coming back.

How was your publishing experience with us?

Honestly, it’s the most intuitive submission process I’ve ever experienced. That’s a major draw for publishing with PeerJ, in my opinion. It’s always disheartening to go through all the work of designing, conducting, and writing up a project to then have to spend an entire day or more just to submit. PeerJ has things very streamlined and the process is fast, so our research can get out to the public as soon as it’s ready.

How would you describe your experience of our review process?

Having also served as a reviewer for PeerJ, I’m very impressed with how intuitive the process is. I appreciate the push for open reviews as well. Having those published alongside an article is a great resource for people wanting a deeper understanding of a paper, and also for early-career scientists to get an idea of how to use reviews to improve their manuscripts.

Would you submit again, and would you recommend that your colleagues submit?

I’ll definitely be submitting future work to PeerJ. Open access and open reviews embody good scientific practices, and the cost is affordable enough that I can sponsor all of my students to submit their work.