title: Diversity and molecular evolution of the RPS2 resistance gene in Arabidopsis thaliana.
abstract: The RPS2 gene in Arabidopsis thaliana governs resistance to strains of the bacterial pathogen, Pseudomonas syringae pv. tomato, that express the avrRpt2 gene. The two loci are involved in a gene-for-gene interaction. Seventeen accessions of A. thaliana were sequenced to explore the diversity present in the coding region of the RPS2 locus. An unusually high level of nucleotide polymorphisms was found (1.26%), with nearly half of the observed polymorphisms resulting in amino acid changes in the RPS2 protein. Seven haplotypes (alleles) were identified and their evolutionary relationships deduced. Several of the alleles conferring resistance were found to be closely related, whereas susceptibility to disease was conferred by widely divergent alleles. The possibility of selection at the RPS2 locus is discussed.
authors.affiliation: Department of Biology, Washington University, St. Louis, MO 63130, USA. alcaiced@artsci.wustl.edu
authors.forename: A L
authors.initials: AL
authors.lastname: Caicedo
authors.forename: B A
authors.initials: BA
authors.lastname: Schaal
authors.forename: B N
authors.initials: BN
authors.lastname: Kunkel
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D019143:Evolution, Molecular; D017343:Genes, Plant; D014644:Genetic Variation; D006239:Haplotypes; D010935:Plant Diseases / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics*; D011549:Pseudomonas; D012641:Selection, Genetic; D017422:Sequence Analysis, DNA
chemical_list: D029681:Arabidopsis Proteins; D010940:Plant Proteins; C089426:RPS2 protein, Arabidopsis