Morphological and Molecular Evidence of Arbuscular Mycorrhizal Fungal Associations in Costa Rican Epiphytic Bromeliads1

Authors

  • Annette R. Rowe,

    Corresponding author
    1. Department of Plant and Microbial Biology, 111 Koshland Hall, University of California, Berkeley, California 94720-3102, U.S.A.
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  • Anne Pringle

    1. Department of Plant and Microbial Biology, 111 Koshland Hall, University of California, Berkeley, California 94720-3102, U.S.A.
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  • 1

    Received 23 February 2004; revision accepted 12 September 2004.

Corresponding author; e-mail: annierow@berkeley.edu

ABSTRACT

Arbuscular mycorrhizal fungi influence the growth, morphology, and fitness of a variety of plant species, but little is known of the arbuscular mycorrhizal (AM) fungal associations of plant species in forest canopies. Plant species' associations with AM fungi are most often elucidated by examining the roots for fungal structures; however, morphological data may provide a limited resolution on a plant's mycorrhizal status. We combined a traditional staining technique with a molecular marker (the 18S ribosomal gene) to determine whether or not a variety of epiphytic bromeliads form arbuscular mycorrhizal fungal associations. Using these methods we show that the epiphytic bromeliad Vriesea werkleana forms arbuscular mycorrhizal fungal associations with members of the genus Glomus. AM fungal sequences of this plant species formed three distinct clades nested within a larger Glomus clade; two of the clades did not group with any previously sequenced lineage of Glomus. Novel clades may represent novel species. Although Vriesea werkleana is associated with multiple AM fungal species, each individual plant is colonized by a single lineage. The combination of morphological and molecular methods provides a practical approach to the characterization of the mycorrhizal status of epiphytic bromeliads, and perhaps other tropical epiphytes.

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