TWO-STEP INFECTION PROCESSES CAN LEAD TO COEVOLUTION BETWEEN FUNCTIONALLY INDEPENDENT INFECTION AND RESISTANCE PATHWAYS
Article first published online: 23 FEB 2012
© 2012 The Author(s).
Volume 66, Issue 7, pages 2030–2041, July 2012
How to Cite
Fenton, A., Antonovics, J. and Brockhurst, M. A. (2012), TWO-STEP INFECTION PROCESSES CAN LEAD TO COEVOLUTION BETWEEN FUNCTIONALLY INDEPENDENT INFECTION AND RESISTANCE PATHWAYS. Evolution, 66: 2030–2041. doi: 10.1111/j.1558-5646.2012.01578.x
- Issue published online: 3 JUL 2012
- Article first published online: 23 FEB 2012
- Accepted manuscript online: 1 FEB 2012 03:02PM EST
- Received June 6, 2011, Accepted December 17, 2011
- infection genetics;
- linkage disequilibrium;
- plant pathogens;
There is growing evidence that successful infection of hosts by pathogens requires a series of independent steps. However, how multistep infection processes affect host–pathogen coevolution is unclear. We present a coevolutionary model, inspired by empirical observations from a range of host–pathogen systems, where the infection process consists of the following two steps: the first is for the pathogen to recognize and locate a suitable host, and the second is to exploit the host while evading immunity. Importantly, these two steps conform to different models of infection genetics: inverse-gene-for-gene (IGFG) and gene-for-gene (GFG), respectively. We show that coevolution under this scenario can lead to coupled gene frequency changes across these two systems. In particular, selection often favors pathogens that are infective at the first, IGFG, step and hosts that are resistant at the second, GFG, step. Hence, there may be signals of positive selection between functionally independent systems whenever there are multistep processes determining resistance and infectivity. Such multistep infection processes are a fundamental, but overlooked feature of many host–pathogen interactions, and have important consequences for our understanding of host–pathogen coevolution.