 | Shefferson, R.P., M. Weiss, T. Kull, and D.L. Taylor. 2005. High specificity | |
| generally characterizes mycorrhizal association in rare lady's slipper orchids, genus Cypripedium. Molecular Ecology 14:613-626 |
Abstract Lady's slipper orchids (Cypripedium spp.) are rare terrestrial plants that
grow throughout the temperate Northern Hemisphere. Like all orchids, they require
mycorrhizal fungi for germination and seedling nutrition. The nutritional relationships
of adult Cypripedium mycorrhizae are unclear; however, Cypripedium distribution may
be limited by mycorrhizal specificity, whether this specificity occurs only during the
seedling stage or carries on into adulthood. We attempted to identify the primary
mycorrhizal symbionts for 100 Cypripedium plants, and successfully did so with two
Cypripedium calceolus, 10 Cypripedium californicum, six Cypripedium candidum, 16
Cypripedium fasciculatum, two Cypripedium guttatum, 12 Cypripedium montanum,
and 11 Cypripedium parviflorum plants from a total of 44 populations in Europe and
North America, yielding fungal nuclear large subunit and mitochondrial large subunit
sequence and RFLP (restriction fragment length polymorphism) data for 59 plants.
Because orchid mycorrhizal fungi are typically observed without fruiting structures, we
assessed fungal identity through direct PCR (polymerase chain reaction) amplification
of fungal genes from mycorrhizally colonized root tissue. Phylogenetic analysis
revealed that the great majority of Cypripedium mycorrhizal fungi are members of
narrow clades within the fungal family Tulasnellaceae. Rarely occurring root
endophytes include members of the Sebacinaceae, Ceratobasidiaceae, and the
ascomycetous genus, Phialophora. C. californicum was the only orchid species with
apparently low specificity, as it associated with tulasnelloid, ceratobasidioid, and
sebacinoid fungi in roughly equal proportion. Our results add support to the growing
literature showing that high specificity is not limited to nonphotosynthetic plants, but
also occurs in photosynthetic ones.
Article copyright notice: © 2005 by Blackwell Publishing Ltd.
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Copyright 2009 Richard P. Shefferson. All rights reserved.
Shefferson et al. 2005
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