Melissa Cregger
A diverse group of fungi lives in symbiosis with poplar trees, sharing water and nutrients in a complex and mutually beneficial system. Understanding these interactions provides an opportunity to engineer ecosystems — maximizing soil health, mitigating adverse impacts on climate and producing resilient plants.
Because poplars grow rapidly and in many regions, they have the potential to be grown in plantations for biofuel feedstock. Melissa Cregger, an ecologist in the Biosciences Division, studies these interactions with the aim of increasing drought tolerance in poplars. For her Early Career Research Program award project, Cregger is investigating optimal poplar “holobiont,” the term used for the biological unit consisting of a tree plus all the symbiotic microorganisms interacting with its roots.
“I like to think about nutrient cycling, carbon cycling and nitrogen cycling,” she said. “I’m interested in the ways that plants and microbes interact and how can we use these interactions to alleviate climate change and increase carbon cycling in the soil. But, to do those things, we have to understand the molecular basis for how these interactions occur.”
Poplars are unique in that they can form associations with both arbuscular and ectomycorrhizal fungi. Cregger hopes to manipulate those interactions to learn more about how each operates and in which situations it might be beneficial to have more or less of one or the other.
In addition to her work at ORNL, Cregger holds a joint appointment at the University of Tennessee and is a faculty mentor in a USDA Research and Extension Experience for Undergraduates called Explore BiGG Data. The program seeks to prepare talented, diverse women for graduate programs and careers in bioinformatics, genetics and genomic sciences. Cregger draws upon her own experiences as a first-generation college student navigating graduate school and the path to finding her career focus.
“I’m passionate about this,” she said. “I want to increase the representation of women and minorities in the sciences and to mentor people like me, who didn’t know science was an option.”
Cregger also highly values the team structure and collaborative nature of working at ORNL.
“I’ve had amazing mentorship to get to this point,” she said. “A lot of people invested in me and gave me valuable feedback on my proposal.
“I think it’s important to recognize the support I’ve received. It wasn’t just me; many people have put in hard work to get me here.”
