title: Resistance to Dutch elm disease reduces presence of xylem endophytic fungi in Elms (Ulmus spp.).
abstract: Efforts to introduce pathogen resistance into landscape tree species by breeding may have unintended consequences for fungal diversity. To address this issue, we compared the frequency and diversity of endophytic fungi and defensive phenolic metabolites in elm (Ulmus spp.) trees with genotypes known to differ in resistance to Dutch elm disease. Our results indicate that resistant U. minor and U. pumila genotypes exhibit a lower frequency and diversity of fungal endophytes in the xylem than susceptible U. minor genotypes. However, resistant and susceptible genotypes showed a similar frequency and diversity of endophytes in the leaves and bark. The resistant and susceptible genotypes could be discriminated on the basis of the phenolic profile of the xylem, but not on basis of phenolics in the leaves or bark. As the Dutch elm disease pathogen develops within xylem tissues, the defensive chemistry of resistant elm genotypes thus appears to be one of the factors that may limit colonization by both the pathogen and endophytes. We discuss a potential trade-off between the benefits of breeding resistance into tree species, versus concomitant losses of fungal endophytes and the ecosystem services they provide.
authors.affiliation: Departamento de Silvopascicultura, Escuela Técnica Superior de Ingenieros de Montes, Universidad Politécnica de Madrid, Madrid, Spain.
authors.forename: Juan A
authors.initials: JA
authors.lastname: Martín
authors.forename: Johanna
authors.initials: J
authors.lastname: Witzell
authors.forename: Kathrin
authors.initials: K
authors.lastname: Blumenstein
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Rozpedowska
authors.forename: Marjo
authors.initials: M
authors.lastname: Helander
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Sieber
authors.forename: Luis
authors.initials: L
authors.lastname: Gil
mesh_terms: D044822:Biodiversity; D002934:Cinnamates / Q000737:chemistry; D015169:Colony Count, Microbial; D053630:Depsides / Q000737:chemistry; D004198:Disease Susceptibility / Q000276:immunology; D060026:Endophytes / Q000276:immunology / Q000302:isolation & purification; D005658:Fungi / Q000276:immunology / Q000302:isolation & purification; D010636:Phenols / Q000737:chemistry; D024301:Plant Bark / Q000737:chemistry / Q000382:microbiology; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology*; D018515:Plant Leaves / Q000737:chemistry / Q000382:microbiology; D013030:Spain; D014197:Trees; D034403:Ulmus / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D052584:Xylem / Q000737:chemistry / Q000276:immunology / Q000382:microbiology*; D000097123:Rosmarinic Acid
chemical_list: D002934:Cinnamates; D053630:Depsides; D010636:Phenols; D000097123:Rosmarinic Acid