Host-mutualist-pathogen interactions

Both plant species and genotypes within a species vary in the severity of disease
symptoms, perhaps due to differences in tolerance (ability of the plant to recover after infection), susceptibility (probability of infection when exposed to the pathogen) or resistance (ability of the plant to defend against infection). Association with other microbes such as mutualists may induce phenotypic changes in plants that alter the intensity, outcome and even the symbiotic state (mutualistic, parasitic, or commensal) of an association (Rúa & Umbanhowar, 2015, Theoretical Ecology). Furthermore, plant pathogens and mutualists may modify plant nutrient allocation in response to abiotic environmental changes (Rúa et al. 2011 Current Opinion in Virology, Rúa & Umbanhowar, 2015, Theoretical Ecology).

My work indicates that the type of mutualistic


Former undergraduate research assistant Briana Whitaker takes photosynthesis measurements during her honors thesis project in 2011.

relationship is important for determining plant response to pathogen infection:

Further collaborative work with other members of the Mitchell lab at UNC-Chapel Hill indicates that direct amendments to host nutritional status lead to increases in viral titer across a number of host species (Cronin et al. 2014 American Naturalist), and produced an undergraduate honors thesis demonstrating increased titer for hosts across a gradient of nutrient values (Whitaker et al. 2015 New Phytologist).

Collaborators: James Umbanhowar (UNC), Charles Mitchell (UNC), Briana Whitaker (IU), James P. Cronin (USGS)


Rúa M.A, Pollina E.C., Power A.G., Mitchell C.E. 2011. The role of viruses in biological invasions: friend or foe? Current Opinion in Virology. 1:68-72.

Cronin, J.P., Rúa, M.A., Mitchell, C.E. 2014. Why is living fast dangerous? Disentangling the roles of resistance and tolerance of disease American Naturalist.184:172-187.

Whitaker, B.*, Rúa, M.A., Mitchell, C.E. 2015. Viral pathogen production in a wild grass host driven by host growth and soil nitrogen. New Phytologist. 207(3):760-768.

Rúa, M.A. & Umbanhowar, J. 2015. The effect of mutualists on pathogen-host dynamics. Theoretical Ecology. 8(1):133-148.