title: A novel cost of R gene resistance in the presence of disease.
abstract: Resistance responses can impose fitness costs when pests are absent. Here, we test whether the induction of resistance can decrease fitness even in plants under attack; we call this potential outcome a net cost with attack. Using lines in which genetic background was controlled, we investigated whether susceptible Arabidopsis thaliana plants can outperform R gene resistant plants when infected with pathogens. For the R gene RPS2, there was a fitness benefit of resistance in the presence of intraspecific competition, but there was a net cost in the absence of competition: resistant plants produced less seed than susceptible plants even though infected with Pseudomonas syringae. This net cost was primarily due to overcompensation by susceptible plants, which occurred because of a developmental response to infection. For the R gene RPP5, there was no fitness effect of resistance without competition but a net cost when plants were infected with Peronospora parasitica in the presence of competition. This net cost was due to a reduction in the fitness of infected, resistant plants and complete compensation in susceptible plants. A spatially variable model suggests that a trade-off between net benefits and net costs with attack may help explain the persistence of individuals lacking R gene resistance to disease.
authors.affiliation: Department of Ecology and Evolution, University of Chicago, Chicago, Illinois 60637, USA. tonia_korves@brown.edu
authors.forename: Tonia
authors.initials: T
authors.lastname: Korves
authors.forename: Joy
authors.initials: J
authors.lastname: Bergelson
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000382:microbiology*; D029681:Arabidopsis Proteins / Q000235:genetics*; D005075:Biological Evolution; D004734:Energy Metabolism; D017343:Genes, Plant; D020022:Genetic Predisposition to Disease; D008954:Models, Biological; D009154:Mutation; D044742:Peronospora; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology*; D044224:Pseudomonas syringae
chemical_list: D029681:Arabidopsis Proteins; C107295:RPP5 protein, Arabidopsis; C089426:RPS2 protein, Arabidopsis