New Soil Microbiologist Aims To Study Plant-Microbe Relationships, Improve Crop Growth
Microbiology researcher Mark McDonald becomes new assistant professor
By Maddie Johnson – Aug. 18, 2025
FAYETTEVILLE, Ark. — Following an unexpected path from dreams of medical school to agricultural science, soil microbiologist Mark McDonald is eager to improve soil health and crop growth by investigating plant-microbe relationships.
“A lot of people have heard of the human gut microbiome, and they understand if your gut microbiome is changed after taking antibiotics, you’re not going to feel super great,” McDonald said.
He said plants are similar.
Plants need nutrients, and microbes are how they get them, so the relationship is mutually beneficial, he explained.
“If we can understand that relationship better, we can manage our production better to make it easier on the plant and potentially reduce fertilizer costs,” he said. “At the end of the day, I want to be able to go to a field day and tell farmers the biology side of things that could help or hurt plant growth.”
McDonald joined the crop, soil and environmental sciences department last month as an assistant professor. He will conduct research and teach courses as part of the Arkansas Agricultural Experiment Station, the research arm of the University of Arkansas System Division of Agriculture, and the Dale Bumpers College of Agricultural, Food and Life Sciences at the University of Arkansas.
Changing plans
As an undergraduate at the University of Tennessee, McDonald originally planned to attend medical school. To bolster his resume, McDonald first pursued research experience as a sophomore in an aquatic microbiology lab. Between his sophomore and junior years, he also spent the summer working at a research farm.
“I was really surprised because I saw people doing science in the field,” he said. “They got to drive tractors and be outside. This seemed better than being inside all the time.”
While attending a Medical College Admission Test prep course, the instructor asked the students, “Why do you want to be a doctor?”
It got McDonald thinking about his true interests, eventually leading him to a master’s degree in plant and soil science from Texas Tech University. He remained in Texas for his doctoral work, earning a Ph.D. in soil science focusing on soil microbiology from Texas A&M University.
Fostering student success
Recalling the mentors that inspired him, McDonald said he sees it as his duty to pay mentorship forward.
“I’m very passionate about making it accessible for students from backgrounds that may not have the same opportunities to pursue their interests,” he said of research and graduate school experiences.
As an example, McDonald described a research experience that brings students from across the country to New Hampshire for skills training and then to Sweden for research. He heard about the program as a postdoctoral scholar in Chicago at Argonne National Laboratory, where he connected with the group of microbiologists who lead the 10-week summer research experience funded by the National Science Foundation.
He said experiences like these are crucial to providing students with connections and allowing them to present their research at meetings.
To learn more about the Division of Agriculture research, visit the Arkansas Agricultural Experiment Station website. Follow us on 𝕏 at @ArkAgResearch, subscribe to the Food, Farms and Forests podcast and sign up for our monthly newsletter, the Arkansas Agricultural Research Report. To learn more about the Division of Agriculture, visit uada.edu. Follow us on 𝕏 at @AgInArk. To learn about extension programs in Arkansas, contact your local Cooperative Extension Service agent or visit uaex.uada.edu.
About the Division of Agriculture
The University of Arkansas System Division of Agriculture’s mission is to strengthen agriculture, communities, and families by connecting trusted research to the adoption of best practices. Through the Agricultural Experiment Station and the Cooperative Extension Service, the Division of Agriculture conducts research and extension work within the nation’s historic land grant education system.
The Division of Agriculture is one of 20 entities within the University of Arkansas System. It has offices in all 75 counties in Arkansas and faculty on three campuses.
Pursuant to 7 CFR § 15.3, the University of Arkansas System Division of Agriculture offers all its Extension and Research programs and services (including employment) without regard to race, color, sex, national origin, religion, age, disability, marital or veteran status, genetic information, sexual preference, pregnancy or any other legally protected status, and is an equal opportunity institution.
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