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Title: Empirical Support for the Virulence-Transmission Tradeoff Hypothesis in Melampsora lini
Authors: Escoto, Andrea
Advisors: Metcalf, C. Jessica
Department: Ecology and Evolutionary Biology
Certificate Program: Global Health and Health Policy Program
Class Year: 2022
Abstract: Understanding how pathogens evolve is relevant to human health, agriculture, and how species interact in our world. One long-held theory predicts that pathogens should evolve to become avirulent, or not cause damage, since they depend on their host to survive. While there is evidence in support for the avirulence hypothesis, the hypothesis does not adequately explain pathogen evolution. In order to replicate inside of a host, pathogens consume and damage host tissues and resources, meaning that they always cause some amount of virulence. The "tradeoff" hypothesis was proposed as an alternative explanation for how pathogens evolve. In this model, pathogens face a tradeoff between their level of transmission and the amount of damage they inflict upon their hosts. An increase in the abundance of a pathogen within a host increases the likelihood of transmission, but it also increases the likelihood of host mortality. The hypothesis suggests that there is an optimal level of virulence that maximizes a pathogen’s transmission. Much theoretical work has been done on the tradeoff hypothesis, but few empirical studies have been conducted to study the relationship in plant systems. In this study, I aimed to determine if there is evidence of a tradeoff between transmission and virulence in Melampsora lini. I used logistic regression and generalized additive modeling to investigate the relationship between the transmission and virulence of flax rust. Transmission was approximated by using the area under the disease progress curve, while virulence was represented by a plant’s probability of mortality based on the intensity of infection. My results support the presence of a tradeoff in the flax and flax rust system.
Type of Material: Princeton University Senior Theses
Language: en
Appears in Collections:Ecology and Evolutionary Biology, 1992-2022
Global Health and Health Policy Program, 2017-2022

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