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Resistance to Dutch elm disease reduces presence of xylem endophytic fungi in Elms (Ulmus spp.).

Martín JA, Witzell J, Blumenstein K, Rozpedowska E, Helander M, Sieber TN, Gil L - PLoS ONE (2013)

Bottom Line: Efforts to introduce pathogen resistance into landscape tree species by breeding may have unintended consequences for fungal diversity.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.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.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Silvopascicultura, Escuela Técnica Superior de Ingenieros de Montes, Universidad Politécnica de Madrid, Madrid, Spain.

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.

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Accumulation curves of elm endophytic fungi.Accumulation curves indicating the number of endophyte morphotaxa isolated per number of twigs processed (four twigs per tree, and four leaf, bark and xylem samples per twig) in each tree group [P (R) = resistant U. pumila clones from Puerta de Hierro Forest Breeding Centre; M (R) = resistant U. minor clones from Puerta de Hierro Forest Breeding Centre; M (S) = susceptible U. minor clones from Puerta de Hierro Forest Breeding Centre; and M (F) = U. minor trees from Rivas-Vaciamadrid field site].
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pone-0056987-g002: Accumulation curves of elm endophytic fungi.Accumulation curves indicating the number of endophyte morphotaxa isolated per number of twigs processed (four twigs per tree, and four leaf, bark and xylem samples per twig) in each tree group [P (R) = resistant U. pumila clones from Puerta de Hierro Forest Breeding Centre; M (R) = resistant U. minor clones from Puerta de Hierro Forest Breeding Centre; M (S) = susceptible U. minor clones from Puerta de Hierro Forest Breeding Centre; and M (F) = U. minor trees from Rivas-Vaciamadrid field site].

Mentions: The sample-based rarefaction curves constructed for individual tissues showed different patterns: within each tree group, the curves for bark tissue increased at highest rate and reached the highest end points, whereas the curves constructed for xylem and leaf samples increased slower and remained at lower levels throughout the empirical range of samples (Fig. 2). Within this range, the curves constructed for bark tissues approached asymptote in all tree groups, and those for the xylem and leaves clearly reached a plateau in M (F) group. The highest end points of the curves constructed for bark and xylem, as well as for all tissues, were found in M (S) group (Fig. 2). The sample-based rarefaction curves based on non-singletons of all tissues reached an asymptote in all tree groups (Fig. 2). After an initial increment, the number of singletons diminished progressively as the number of twigs processed increased (Fig. 2). The initial level of singletons was lowest in M (F) group, reaching zero when the number of processed twigs was 26.


Resistance to Dutch elm disease reduces presence of xylem endophytic fungi in Elms (Ulmus spp.).

Martín JA, Witzell J, Blumenstein K, Rozpedowska E, Helander M, Sieber TN, Gil L - PLoS ONE (2013)

Accumulation curves of elm endophytic fungi.Accumulation curves indicating the number of endophyte morphotaxa isolated per number of twigs processed (four twigs per tree, and four leaf, bark and xylem samples per twig) in each tree group [P (R) = resistant U. pumila clones from Puerta de Hierro Forest Breeding Centre; M (R) = resistant U. minor clones from Puerta de Hierro Forest Breeding Centre; M (S) = susceptible U. minor clones from Puerta de Hierro Forest Breeding Centre; and M (F) = U. minor trees from Rivas-Vaciamadrid field site].
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3585289&req=5

pone-0056987-g002: Accumulation curves of elm endophytic fungi.Accumulation curves indicating the number of endophyte morphotaxa isolated per number of twigs processed (four twigs per tree, and four leaf, bark and xylem samples per twig) in each tree group [P (R) = resistant U. pumila clones from Puerta de Hierro Forest Breeding Centre; M (R) = resistant U. minor clones from Puerta de Hierro Forest Breeding Centre; M (S) = susceptible U. minor clones from Puerta de Hierro Forest Breeding Centre; and M (F) = U. minor trees from Rivas-Vaciamadrid field site].
Mentions: The sample-based rarefaction curves constructed for individual tissues showed different patterns: within each tree group, the curves for bark tissue increased at highest rate and reached the highest end points, whereas the curves constructed for xylem and leaf samples increased slower and remained at lower levels throughout the empirical range of samples (Fig. 2). Within this range, the curves constructed for bark tissues approached asymptote in all tree groups, and those for the xylem and leaves clearly reached a plateau in M (F) group. The highest end points of the curves constructed for bark and xylem, as well as for all tissues, were found in M (S) group (Fig. 2). The sample-based rarefaction curves based on non-singletons of all tissues reached an asymptote in all tree groups (Fig. 2). After an initial increment, the number of singletons diminished progressively as the number of twigs processed increased (Fig. 2). The initial level of singletons was lowest in M (F) group, reaching zero when the number of processed twigs was 26.

Bottom Line: Efforts to introduce pathogen resistance into landscape tree species by breeding may have unintended consequences for fungal diversity.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.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.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Silvopascicultura, Escuela Técnica Superior de Ingenieros de Montes, Universidad Politécnica de Madrid, Madrid, Spain.

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.

Show MeSH
Related in: MedlinePlus