Fitness costs of R-gene-mediated resistance in Arabidopsis thaliana

Nature. 2003 May 1;423(6935):74-7. doi: 10.1038/nature01588.


Resistance genes (R-genes) act as an immune system in plants by recognizing pathogens and inducing defensive pathways. Many R-gene loci are present in plant genomes, presumably reflecting the need to maintain a large repertoire of resistance alleles. These loci also often segregate for resistance and susceptibility alleles that natural selection has maintained as polymorphisms within a species for millions of years. Given the obvious advantage to an individual of being disease resistant, what prevents these resistance alleles from being driven to fixation by natural selection? A cost of resistance is one potential explanation; most models require a lower fitness of resistant individuals in the absence of pathogens for long-term persistence of susceptibility alleles. Here we test for the presence of a cost of resistance at the RPM1 locus of Arabidopsis thaliana. Results of a field experiment comparing the fitness of isogenic strains that differ in the presence or absence of RPM1 and its natural promoter reveal a large cost of RPM1, providing the first evidence that costs contribute to the maintenance of an ancient R-gene polymorphism.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alleles
  • Arabidopsis / genetics*
  • Arabidopsis / physiology*
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism*
  • Genes, Plant / genetics*
  • Haplotypes / genetics
  • Immunity, Innate / genetics
  • Models, Biological
  • Phenotype
  • Polymerase Chain Reaction
  • Polymorphism, Genetic / genetics*
  • Promoter Regions, Genetic / genetics
  • Seeds / genetics
  • Seeds / physiology
  • Selection, Genetic


  • Arabidopsis Proteins
  • RPM1 protein, Arabidopsis