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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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Two-dimensional ordination using non-metric multidimensional scaling (MDS) based on Jaccard’s similarity measures.Each point represents the fungal endophyte community of an individual tree. Endophytes were isolated from leaf (a), bark (b) or xylem (c) tissues. Groups of elm trees: 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-g004: Two-dimensional ordination using non-metric multidimensional scaling (MDS) based on Jaccard’s similarity measures.Each point represents the fungal endophyte community of an individual tree. Endophytes were isolated from leaf (a), bark (b) or xylem (c) tissues. Groups of elm trees: 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 MSD graph obtained from the Jaccard’s similarity matrix showed a clear distinction in leaf endophyte community between the M (F) trees and the trees from the Breeding Centre (Fig. 4a). The same analysis applied to the bark endophytes revealed a higher overlap among tree groups than in leaf or xylem tissues (Fig. 4b). However, M (F) samples were grouped in the positive horizontal semi-axis together with a M (S) tree from the Breeding Centre. This M (S) tree is the UPM007 clone (Table 1), belonging to the U. minor var. vulgaris complex, which also includes the trees studied at the field population. For the xylem-associated endophyte communities (Fig. 4c), a clear distinction was again observed between M (F) and the trees from the Breeding Centre. Furthermore, a clear distinction in endophyte diversity was observed between the M (R) trees on the one hand, and the M (S) and P (R) trees on the other hand (Fig. 4c).


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)

Two-dimensional ordination using non-metric multidimensional scaling (MDS) based on Jaccard’s similarity measures.Each point represents the fungal endophyte community of an individual tree. Endophytes were isolated from leaf (a), bark (b) or xylem (c) tissues. Groups of elm trees: 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-g004: Two-dimensional ordination using non-metric multidimensional scaling (MDS) based on Jaccard’s similarity measures.Each point represents the fungal endophyte community of an individual tree. Endophytes were isolated from leaf (a), bark (b) or xylem (c) tissues. Groups of elm trees: 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 MSD graph obtained from the Jaccard’s similarity matrix showed a clear distinction in leaf endophyte community between the M (F) trees and the trees from the Breeding Centre (Fig. 4a). The same analysis applied to the bark endophytes revealed a higher overlap among tree groups than in leaf or xylem tissues (Fig. 4b). However, M (F) samples were grouped in the positive horizontal semi-axis together with a M (S) tree from the Breeding Centre. This M (S) tree is the UPM007 clone (Table 1), belonging to the U. minor var. vulgaris complex, which also includes the trees studied at the field population. For the xylem-associated endophyte communities (Fig. 4c), a clear distinction was again observed between M (F) and the trees from the Breeding Centre. Furthermore, a clear distinction in endophyte diversity was observed between the M (R) trees on the one hand, and the M (S) and P (R) trees on the other hand (Fig. 4c).

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