Marilyn J. Roossinck

Marilyn J. Roossinck is an American virologist and professor emerita of virus ecology at Pennsylvania State University. She is known for her research on the ecology and evolution of RNA viruses and plants, particularly her work demonstrating mutualistic relationships between viruses and their hosts.

Education Roossinck grew up in rural Michigan, and is of German-Dutch ancestry. She received two B.A. degrees from the University of Colorado, Boulder in 1982, in Molecular Biology and in Evolutionary Biology. She completed her Ph.D. in Microbiology and Immunology at the University of Colorado School of Medicine in 1986, her doctoral research focused on the molecular biology of hepatitis B virus. She undertook a postdoctoral fellowship in plant virology at Cornell University, studying the genetics and evolution of cucumber mosaic virus.

Career In 1991, Roossinck joined the Samuel Roberts Noble Foundation in Ardmore, Oklahoma, as an assistant professor of Plant Biology. In 2011, she moved to Penn State's Center for Infectious Disease Dynamics, Huck Institute of Life Sciences, as a full professor, holding joint appointments in the Department of Plant Pathology and Environmental Microbiology and the Eberly College of Science. She taught a course in virus ecology at Penn State and retired in August 2021. which grows in geothermal soils and depends on a symbiotic fungus, Curvularia protuberata. Roossinck and colleagues discovered that the fungus confers heat tolerance only when it is itself infected by a virus, later named the "Curvularia thermal tolerance virus". When the fungus was cured of the virus, the heat tolerance was lost. The same effect was observed in tomatoes. Roossinck has described this project as the work she is most proud of. In a 2011 review in Nature Reviews Microbiology, she catalogued mutualistic virus-host relationships across bacteria, fungi, plants, insects, and mammals, including cases where viruses confer drought tolerance, cold tolerance, or protection against unrelated pathogens.