title: Suppressed recombination and unique candidate genes in the divergent haplotype encoding Fhb1, a major Fusarium head blight resistance locus in wheat.
abstract: Fine mapping and sequencing revealed 28 genes in the non-recombining haplotype containing Fhb1 . Of these, only a GDSL lipase gene shows a pathogen-dependent expression pattern. Fhb1 is a prominent Fusarium head blight resistance locus of wheat, which has been successfully introgressed in adapted breeding material, where it confers a significant increase in overall resistance to the causal pathogen Fusarium graminearum and the fungal virulence factor and mycotoxin deoxynivalenol. The Fhb1 region has been resolved for the susceptible wheat reference genotype Chinese Spring, yet the causal gene itself has not been identified in resistant cultivars. Here, we report the establishment of a 1 Mb contig embracing Fhb1 in the donor line CM-82036. Sequencing revealed that the region of Fhb1 deviates from the Chinese Spring reference in DNA size and gene content, which explains the repressed recombination at the locus in the performed fine mapping. Differences in genes expression between near-isogenic lines segregating for Fhb1 challenged with F. graminearum or treated with mock were investigated in a time-course experiment by RNA sequencing. Several candidate genes were identified, including a pathogen-responsive GDSL lipase absent in susceptible lines. The sequence of the Fhb1 region, the resulting list of candidate genes, and near-diagnostic KASP markers for Fhb1 constitute a valuable resource for breeding and further studies aiming to identify the gene(s) responsible for F. graminearum and deoxynivalenol resistance.
authors.affiliation: Institute for Biotechnology in Plant Production (IFA-Tulln), BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Strasse 20, 3430, Tulln, Austria. wolfgang.schweiger@boku.ac.at.
authors.forename: W
authors.initials: W
authors.lastname: Schweiger
authors.affiliation: Institute for Biotechnology in Plant Production (IFA-Tulln), BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Strasse 20, 3430, Tulln, Austria.
authors.forename: B
authors.initials: B
authors.lastname: Steiner
authors.affiliation: French Plant Genomic Resource Centre, INRA-CNRGV, Chemin de Borde Rouge, CS 52627, 31326, Castanet Tolosan, France.
authors.forename: S
authors.initials: S
authors.lastname: Vautrin
authors.affiliation: Plant Genome and Systems Biology, Helmholtz Zentrum München, 85764, Neuherberg, Germany.|Division of Computational System Biology, Department of Microbiology and Ecosystem Science, University of Vienna, 1090, Vienna, Austria.
authors.forename: T
authors.initials: T
authors.lastname: Nussbaumer
authors.affiliation: Institute for Biotechnology in Plant Production (IFA-Tulln), BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Strasse 20, 3430, Tulln, Austria.|Department of Applied Genetics and Cell Biology, BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Strasse 22, 3430, Tulln, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Siegwart
authors.affiliation: Institute for Biotechnology in Plant Production (IFA-Tulln), BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Strasse 20, 3430, Tulln, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Zamini
authors.affiliation: Institute for Biotechnology in Plant Production (IFA-Tulln), BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Strasse 20, 3430, Tulln, Austria.
authors.forename: F
authors.initials: F
authors.lastname: Jungreithmeier
authors.affiliation: Institute for Biotechnology in Plant Production (IFA-Tulln), BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Strasse 20, 3430, Tulln, Austria.
authors.forename: V
authors.initials: V
authors.lastname: Gratl
authors.affiliation: Institute for Biotechnology in Plant Production (IFA-Tulln), BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Strasse 20, 3430, Tulln, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Lemmens
authors.affiliation: Plant Genome and Systems Biology, Helmholtz Zentrum München, 85764, Neuherberg, Germany.
authors.forename: K F X
authors.initials: KF
authors.lastname: Mayer
authors.affiliation: French Plant Genomic Resource Centre, INRA-CNRGV, Chemin de Borde Rouge, CS 52627, 31326, Castanet Tolosan, France.
authors.forename: H
authors.initials: H
authors.lastname: Bérgès
authors.affiliation: Department of Applied Genetics and Cell Biology, BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Strasse 22, 3430, Tulln, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Adam
authors.affiliation: Institute for Biotechnology in Plant Production (IFA-Tulln), BOKU-University of Natural Resources and Life Sciences, Konrad Lorenz Strasse 20, 3430, Tulln, Austria.
authors.forename: H
authors.initials: H
authors.lastname: Buerstmayr
mesh_terms: D020451:Contig Mapping; D060467:Disease Resistance / Q000235:genetics*; D005670:Fusarium; D056426:Genetic Loci; D005838:Genotype; D006239:Haplotypes; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D018749:RNA, Plant / Q000235:genetics; D011995:Recombination, Genetic; D017423:Sequence Analysis, RNA; D014255:Trichothecenes; D014908:Triticum / Q000235:genetics* / Q000382:microbiology
chemical_list: D018749:RNA, Plant; D014255:Trichothecenes; C007262:deoxynivalenol