title: Fine genetic mapping of RXopJ4, a bacterial spot disease resistance locus from Solanum pennellii LA716.
abstract: The RXopJ4 resistance locus from the wild accession Solanum pennellii (Sp) LA716 confers resistance to bacterial spot disease of tomato (S. lycopersicum, Sl) caused by Xanthomonas perforans (Xp). RXopJ4 resistance depends on recognition of the pathogen type III effector protein XopJ4. We used a collection of Sp introgression lines (ILs) to narrow the RXopJ4 locus to a 4.2-Mb segment on the long arm of chromosome 6, encompassed by the ILs 6-2 and 6-2-2. We then adapted or developed a collection of 14 molecular markers to map on a segregating F(2) population from a cross between the susceptible parent Sl FL8000 and the resistant parent RXopJ4 8000 OC(7). In the F(2) population, a 190-kb segment between the markers J350 and J352 cosegregated with resistance. This fine mapping will enable both the identification of candidate genes and the detection of resistant plants using cosegregating markers. The RXopJ4 resistance gene(s), in combination with other recently characterized genes and a quantitative trait locus (QTL) for bacterial spot disease resistance, will likely be an effective tool for the development of durable resistance in cultivated tomato.
authors.affiliation: Department of Plant and Microbial Biology, University of California, 111 Koshland Hall, Berkeley, CA 94720, USA. sharlach@berkeley.edu
authors.forename: Molly
authors.initials: M
authors.lastname: Sharlach
authors.forename: Douglas
authors.initials: D
authors.lastname: Dahlbeck
authors.forename: Lily
authors.initials: L
authors.lastname: Liu
authors.forename: Joshua
authors.initials: J
authors.lastname: Chiu
authors.forename: José M
authors.initials: JM
authors.lastname: Jiménez-Gómez
authors.forename: Seisuke
authors.initials: S
authors.lastname: Kimura
authors.forename: Daniel
authors.initials: D
authors.lastname: Koenig
authors.forename: Julin N
authors.initials: JN
authors.lastname: Maloof
authors.forename: Neelima
authors.initials: N
authors.lastname: Sinha
authors.forename: Gerald V
authors.initials: GV
authors.lastname: Minsavage
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Jones
authors.forename: Robert E
authors.initials: RE
authors.lastname: Stall
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Staskawicz
mesh_terms: D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D018744:DNA, Plant / Q000235:genetics; D060467:Disease Resistance / Q000235:genetics*; D017343:Genes, Plant; D005819:Genetic Markers; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D040641:Quantitative Trait Loci; D017422:Sequence Analysis, DNA; D032322:Solanum / Q000235:genetics* / Q000382:microbiology; D014974:Xanthomonas / Q000302:isolation & purification
chemical_list: D018744:DNA, Plant; D005819:Genetic Markers