High specificity generally characterizes mycorrhizal association in rare lady’s slipper orchids, genus Cypripedium. Mol Ecol

Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, United States
Molecular Ecology (Impact Factor: 6.49). 03/2005; 14(2):613-26. DOI: 10.1111/j.1365-294X.2005.02424.x
Source: PubMed


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.

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Available from: Richard Shefferson
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    • "Although it has been hypothesized that mycorrhizal specificity is associated with rarity in orchids, the recent proliferation of molecular studies of orchid–fungal relationships is revealing that there is no clear trend between mycorrhizal specificity and the abundance and geographical range size of orchids (McCormick and Jacquemyn, 2014). For example, there are several instances in which rare orchids have been found to utilize multiple fungal species (Shefferson et al., 2005; Jacquemyn et al., 2011; Pandey et al., 2013). As seen in P. deformis, increasingly it is being shown that high mycorrhizal specificity can be associated with widespread host distribution . "
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    ABSTRACT: Methods Mycorrhizal fungi were isolated from P. deformis populations in eastern and western Australia. Germination trials using seed from western Australian populations were conducted to test if these fungi supported germination, regardless of the region in which they occurred. A phylogenetic analysis was undertaken using isolates from P. deformis and other Australian orchids that use the genus Sebacina to test for the occurrence of operational taxonomic units (OTUs) in eastern and western Australia. Key Results With the exception of one isolate, all fungi used by P. deformis belonged to a single fungal OTU of Sebacina. Fungal isolates from eastern and western Australia supported germination of P. deformis. A phylogenetic analysis of Australian Sebacina revealed that all of the OTUs that had been well sampled occurred on both sides of the continent. Conclusions The use of a widespread fungal OTU in P. deformis enables a broad distribution despite high mycorrhizal specificity. The Sebacina OTUs that are used by a range of Australian orchids occur on both sides of the continent, demonstrating that the short-range endemism prevalent in the orchids is not driven by fungal species with narrow distributions. Alternatively, a combination of specific edaphic requirements and a high incidence of pollination by sexual deception may explain biogeographic patterns in southern Australian orchids.
    Full-text · Article · Jun 2015 · Annals of Botany
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    • "Several studies have examined this plant group. Previous studies examined biogeographical patterns, evolution of fungal associations, genome size, and correlation between pollinator activities and fruitset rates (Guo et al. 2012; Shefferson et al. 2005; Cox et al. 1998; Bernhardt and Edens-Meier 2010). Molecular phylogenetic studies of Cypripedium revealed that Cypripedium japonicum Thunb. is similar to Cypripedium formosanum Hayata, which is contained in the section Flabellinervia together with C. japonicum. "
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    ABSTRACT: Reliable and accurate species identification is essential to establish a strategy for monitoring and manipulation of plant populations for conservation biology. However, identification of nonflowering plants is difficult. Based on recent advances in molecular biological techniques, various molecular identification methodologies have been proposed and applied in plant science, with a focus on medicinally valuable species. Lady’s slipper orchids (Cypripedium) are a representative terrestrial orchid group that includes many endangered species. Of 46 species, 3 (Cypripedium japonicum Thunb., Cypripedium macranthos Sw., and Cypripedium guttatum var. koreanum Nakai) were reported from Korea and categorised as endangered species or at risk of becoming endangered because of the rapidly decreasing population. We generated an accurate molecular identification system for these species using the sequence variation and species-specific SNPs of two plastid loci, rpoC2 and the IGS region between atpF and atpH. We selected the atpF-H region for molecular identification of the Korean Cypripedium and related Taiwan-endemic taxon Cypripedium formosanum Hayata. Cypripedium guttatum var. koreanum contained large deletions of over 300 bp, and could be distinguished by electrophoresis. For the other three species, we designed new primers based on a specific insertion (C. macranthos) and SNPs (C. japonicum and C. formosanum). We confirmed that molecular identification enables detection of each species using species-specific primers. © 2015 National Research Council of Canada. All rights reserved.
    Full-text · Article · Jun 2015 · Botany
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    • " n g i i n t h e Tu l a s n e l l a c e a e a n d Ceratobasidiaceae ( e . g . , cantharelloid clade ) has been previous - ly reported ( Otero et al . 2002 ; Ma et al . 2003 ; Suarez et al . 2006 ) . Certain photosynthetic orchids , even when sampled over a wide range , have a single dominant species of Rhizoctonia fungus ( McCormick et al . 2004 ; Shefferson et al . 2005 , 2010 ; Irwin et al . 2007 ) . However , fully mycoheterotrophic ( MH ) orchids , which are achlorophyllous and nutritionally dependent on their mycorrhizal fungi , can be colonized by several different ectomycorrhizal ( ECM ) fungi ( e . g . , Russulaceae and Thelephoraceae fungi ) ( Roy et al . 2009 ; Kennedy et al . 2011 ) as well a"
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    ABSTRACT: The medicinal effects and techniques for cultivating Anoectochilus formosanus are well-documented, but little is known about the mycorrhizal fungi associated with A. formosanus. Rhizoctonia (Thanatephorus) anastomosis group 6 (AG-6) was the most common species isolated from fungal pelotons in native A. formosanus and represented 67 % of the sample. Rhizoctonia (Ceratobasidium) AG-G, P, and R were also isolated and represent the first occurrence in the Orchidaceae. Isolates of AG-6, AG-R, and AG-P in clade I increased seed germination 44–91 % and promoted protocorm growth from phases III to VI compared to asymbiotic treatments and isolates of AG-G in clade II and Tulasnella species in clade III. All isolates in clades I to III formed fungal pelotons in tissue-cultured seedlings of A. formosanus, which exhibited significantly greater growth than nonmycorrhizal seedlings. An analysis of the relative effect of treatment ( \( {\widehat{p}}_i \) ) showed that the low level of colonization ( \( {\widehat{p}}_i = 0.30\hbox{--} 0.47 \) ) by isolates in clade I resulted in a significant increase in seedling growth compared to isolates in clades II (0.63–0.82) and III (0.63–0.75). There was also a negative correlation (r = −0.8801) with fresh plant weight and fungal colonization. Our results suggest that isolates in clade I may represent an important group associated with native populations of A. formosanus and can vary in their ability to establish a symbiotic association with A. formosanus. The results presented here are potentially useful for advancing research on the medicinal properties, production, and conservation of A. formosanus in diverse ecosystems.
    Preview · Article · Jan 2015 · Mycorrhiza
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