Hosts and pathogens are engaged in an ongoing evolutionary struggle. In humanmanaged
systems, rapid evolution of pathogen populations can reduce the
effectiveness of important control methods such as antibiotics and genetic resistance
in crop species. My thesis research investigates potential constraints to pathogen
evolution by examining genetic and ecological factors affecting the evolution of
infection and reproduction in the plant pathogen Puccinia coronata. I first investigate
genetic variation underlying three pathogen life history stages within the host and
show that variation in pathogen life-history stages within the host is affected by both
the pathogen and host genotype. Next, I evaluate the relationship between pathogen
infection and reproduction and show evidence of a trade-off between the number of
resistant host genotypes infected and two key pathogen life history traits. Finally, I
quantify the variation in infection and reproduction among eight different agricultural
populations of P. coronata and ask whether the genetic diversity of the host
population affects the evolution of pathogen infection and reproduction. While I do
not find conclusive evidence that host genetic diversity affects the evolution of these
traits, I do I find significant variation among populations that is not explained by
pathogen population structure, indicating that selection structures pathogen
University of Minnesota Ph.D. dissertation. December 2012. Major: Ecology, Evolution and Behavior. Advisor: Georgiana May. 1 computer file (PDF); viii, 169 pages.
Bruns, Emily Louise.
Genetic and ecological constraints to the evolution of virulence and reproduction in a plant pathogen.
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