title: The genetic basis of quantitative variation in susceptibility of Arabidopsis thaliana to Pseudomonas syringae (Pst DC3000): evidence for a new genetic factor of large effect.
abstract: * Pathogens represent an important threat to plant communities and agriculture, and can shape many aspects of plant evolution. Natural variation in plant disease susceptibility is typically quantitative, yet studies on the molecular basis of disease resistance have focused mainly on qualitative variation. * Here we investigated the genetic architecture of quantitative susceptibility to the bacterium Pseudomonas syringae by performing a quantitative trait locus (QTL) analysis on the F2 progeny of two natural accessions of Arabidopsis thaliana under two nutrient treatments. * We found that a single QTL explains most of the variation (77%) in susceptibility between accessions Columbia (Col-0) and San Feliu-2 (Sf-2), and its effect is independent of nutrients. The Sf-2 allele at this QTL is dominant and can reduce the bacterial population size by 31-fold, much like a classical resistance (R) gene. However, minor QTLs, whose effects are altered by nutrient treatment, were also detected. * Surprisingly, we found that none of the QTLs for susceptibility had any effect on fruit production, suggesting that the use of resistance genes for crop improvement and evolutionary analysis of plant-pathogen interactions requires caution.
authors.affiliation: University of Manchester, Faculty of Life Sciences, Michael Smith Building, Room C.1261, Manchester M13 9PT, UK.
authors.forename: Paula X
authors.initials: PX
authors.lastname: Kover
authors.affiliation: Washington University Medical School, Department of Anatomy and Neurobiology, 660 S. Euclid Ave., St Louis, MO 631110, USA.
authors.forename: James
authors.initials: J
authors.lastname: Cheverud
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology / Q000382:microbiology*; D003433:Crosses, Genetic; D005308:Fertilizers; D005638:Fruit / Q000235:genetics / Q000382:microbiology; D017343:Genes, Plant; D010641:Phenotype; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D044224:Pseudomonas syringae / Q000502:physiology*; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable
chemical_list: D005308:Fertilizers