Joanna Tannous: Harnessing an unlikely climate challenge ally

Joanna Tannous has found the perfect organism to study to satisfy her deeply curious nature, her skills in biochemistry and genetics, and a drive to create solutions for a better world. The organism is a poorly understood life form that greatly influences its environment and is unique enough to deserve its own biological kingdom: fungi.

Humans have for centuries prevailed upon fungi to make bread, beer and wine; to consume as a food source; and more recently to fight infection and create energy. Fungi can also wreak havoc by destroying crops and triggering illness. In studying this mysterious microbe that has more in common with animals than plants, scientists have made a host of discoveries, including how some fungi enhance the ability of plants to absorb and store carbon.

Can fungi help solve the climate crisis? That’s one of the questions fungal geneticist Tannous will address as she takes on a new challenge at the Department of Energy’s Oak Ridge National Laboratory: determining the genetic processes that underlie fungi’s support for carbon storage and asking if they can be modified to do the job better.

Tannous is an awardee in the first round of ORNL’s new Early Career Scientist Laboratory-Directed Research and Development Program. Her project will focus on a better understanding of the genetic mechanisms that cause ectomycorrhizal fungi to form symbioses with plants and develop vast underground networks that provide nutrients, warn of pests and disease and aid carbon sequestration for their hosts.

The project “is the opposite of what I’ve done in the past with pathogenic, or disease-causing fungi, where I try to mitigate their ability to cause harm. Here, I’m trying to enhance the properties of beneficial fungi,” said Tannous, a staff scientist in ORNL’s Biosciences Division.

Tannous first came to ORNL in 2020 as a postdoctoral researcher working within the Secure Ecosystem Engineering and Design Science Focus Area to develop CRISPR-Cas9 gene editing tools to combat Sphaerulina musiva, an invasive fungal pathogen that can damage poplar trees grown as a bioenergy feedstock. The genetic approach she developed will be used to establish  a gene drive, a system designed to outpace natural selection by supporting the rapid spread of a new fungal variant that has been genetically modified to be benign. If successful, it will mark the first gene drive developed on a fungal plant pathogen.

Basic science discoveries lead to applied solutions

“I’ve never felt like my work is a job. It’s more of a passion,” Tannous said. “I enjoy conducting basic science experiments to better understand these organisms that we know so little bit about, and then getting in some applied science by genetically engineering a fungus and evaluating the outcome. That’s what keeps me motivated — that my research never feels routine. There is always something new and unexpected to discover.”

Tannous first became fascinated by fungi as a college senior at St. Joseph University of Beirut, Lebanon.

“The fungal kingdom is very interesting. Even when looking at them on plates, every single fungus has a specific makeup and background. Some can be beneficial, whereas others can be pathogenic. In the past, I spent a lot of time analyzing the virulence factors of a fungus, and at the same time I’d be looking at its beneficial properties. There’s a lot we still don’t know, and there are a lot of fungal species that we have not yet discovered.”

Tannous’ academic journey reflects her interest in both basic and applied science. She earned a bachelor’s in biochemistry, a master’s in food chemistry, and a doctorate in chemistry with a focus in applied fungal genetics from St. Joseph. She also earned a second doctoral degree in pathology, toxicology, genetics and nutrition from the National Polytechnic Institute of Toulouse in France.

As she worked toward those doctorates concurrently, Tannous would spend six months in Lebanon during apple season researching an apple pathogen, and the other six months in France performing fundamental science.

Tannous worked as a postdoctoral researcher at two universities: the University of Wisconsin-Madison’s Department of Medical Microbiology and Immunology, and the Research Institute of Horticulture and Seeds at the University of Angers in France. She began as a postdoc at ORNL in 2020 and was hired as staff in 2022.  

She describes working at ORNL as a middle ground between academia and industry, with the benefits of a deep bench of expertise and facilities under one roof. “Working with a multidisciplinary team at a single institution is a big advantage. I’ve worked with colleagues in the chemical sciences, with computational scientists, and we have supercomputers and sophisticated mass spectrometry to support our research. It’s great to have those internal collaborations and capabilities at your fingertips. You’re also encouraged to publish your work at ORNL, which isn’t always the case in the private sector.”

A drive to succeed and a mother’s influence

When asked about key influencers in her life, Tannous points to her mother.

“I’m a driven individual. I knew early on I wanted to be a scientist, and my mother has supported me every step of the way,” Tannous said. Her father died when Tannous was a toddler. It was her mother who worked tirelessly as a single parent to ensure that her daughter had all the opportunities she needed to succeed.

“My mother taught me to always look for what’s next, in terms of continuing my education and then in my pursuit of a science career,” Tannous said. “She works as an accountant back in Lebanon and says she has no interest in retiring. She tells me, ‘Why would I want to just stay home? I like working.’”

It’s now Joanna’s turn to parent, having given birth to her first child last fall. It’s been a bit of a challenge, she said, being a new mom and at the same time transitioning to staff at ORNL.

“I wouldn’t have had it any other way,” Tannous said. “I’ve achieved my two biggest dreams at the same time — being a mom and stepping into a new phase of my career. I’m happy to be getting the best out of both experiences.”

She cites encouraging colleagues at ORNL who’ve made her success possible. “I get support from Julie Mitchell (Biosciences Division director), Carrie Eckert (group leader), and from my co-workers, particularly all the new moms here. It’s especially good to have advice from colleagues who’ve been in the same situation. We lift each other up, and it helps me to know things won’t always be as challenging as they are now.”

Her advice for young scientists? “Move out of your comfort zone. Challenge yourself. For me, that meant leaving my country, my family, my home, my friends, and challenging myself to succeed.

“You will have failures and rejections along the way. That’s totally normal,” Tannous continued. “You can be disappointed, but don’t get demotivated. Learn how to troubleshoot and to seek advice from others. I’m still at the beginning of my career, and I have ups and downs, but I always look to the future.”

UT-Battelle manages ORNL for the Department of Energy’s Office of Science, the single largest supporter of basic research in the physical sciences in the United States. The Office of Science is working to address some of the most pressing challenges of our time. For more information, please visit energy.gov/science. — Stephanie Seay