title: Co-occurrence and hybridization of anther-smut pathogens specialized on Dianthus hosts.
abstract: Host specialization has important consequences for the diversification and ecological interactions of obligate pathogens. The anther-smut disease of natural plant populations, caused by Microbotryum fungi, has been characterized by specialized host-pathogen interactions, which contribute in part to the isolation among these numerous fungal species. This study investigated the molecular variation of Microbotryum pathogens within the geographic and host-specific distributions on wild Dianthus species in southern European Alps. In contrast to prior studies on this pathogen genus, a range of overlapping host specificities was observed for four delineated Microbotryum lineages on Dianthus hosts, and their frequent co-occurrence within single-host populations was quantified at local and regional scales. In addition to potential consequences for direct pathogen competition, the sympatry of Microbotryum lineages led to hybridization between them in many populations, and these admixed genotypes suffered significant meiotic sterility. Therefore, this investigation of the anther-smut fungi reveals how variation in the degrees of host specificity can have major implications for ecological interactions and genetic integrity of differentiated pathogen lineages.
authors.affiliation: Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA, USA.
authors.forename: Elsa
authors.initials: E
authors.lastname: Petit
authors.affiliation: Biology Department, Amherst College, Amherst, MA, 01002, USA.
authors.forename: Casey
authors.initials: C
authors.lastname: Silver
authors.affiliation: Center for Adaptation to a Changing Environment, ETH Zürich, 8092, Zürich, Switzerland.
authors.forename: Amandine
authors.initials: A
authors.lastname: Cornille
authors.affiliation: UMR BGPI, INRA, Campus International de Baillarguet, 34398, Montpellier, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Gladieux
authors.affiliation: Biology Department, Amherst College, Amherst, MA, 01002, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Rosenthal
authors.affiliation: Department of Biology, University of Virginia, Charlottesville, VA, 22903, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Bruns
authors.affiliation: Biology Department, Amherst College, Amherst, MA, 01002, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Yee
authors.affiliation: Department of Biology, University of Virginia, Charlottesville, VA, 22903, USA.
authors.forename: Janis
authors.initials: J
authors.lastname: Antonovics
authors.affiliation: Ecologie Systematique Evolution, CNRS, University of Paris-Sud, AgroParisTech, Université Paris-Saclay, 91400, Orsay, France.
authors.forename: Tatiana
authors.identifier: http://orcid.org/0000-0002-2685-6478
authors.initials: T
authors.lastname: Giraud
authors.affiliation: Biology Department, Amherst College, Amherst, MA, 01002, USA.
authors.forename: Michael E
authors.identifier: http://orcid.org/0000-0003-4379-0711
authors.initials: ME
authors.lastname: Hood
mesh_terms: D001487:Basidiomycota / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics; D029749:Dianthus / Q000382:microbiology*; D005060:Europe; D005838:Genotype; D058507:Host Specificity; D006824:Hybridization, Genetic; D018895:Microsatellite Repeats; D010935:Plant Diseases / Q000382:microbiology; D060047:Reproductive Isolation; D017422:Sequence Analysis, DNA; D061350:Sympatry
chemical_list: D004271:DNA, Fungal
keywords: 
  Microbotryum violaceum
  ; generalist; host range; host shift; introgression; pathogen sympatry; secondary contact