TY - JOUR

T1 - Co-occurring orchid species associated with different low-abundance mycorrhizal fungi from the soil in a high-diversity conservation area in Denmark

AU - Hartvig, Ida

AU - Kosawang, Chatchai

AU - Rasmussen, Hanne

AU - Kjær, Erik Dahl

AU - Nielsen, Lene Rostgaard

N1 - Funding Information: We thank Lene Hasmark Andersen for extracting DNA from soil samples. Melissa McCormick is thanked for providing information on suitable OMF primers and PCR conditions. Lea Vig McKinney helped screening seed packets for protocorms. We are grateful to Danish Nature Agency in Storstrøm for collaboration and access to field sites throughout the project. The project was supported by Godfred Birkedal Hartmanns Familiefond and infrastructure at the Center for Evolutionary Hologenomics was funded by the Danish National Research Foundation grant DNRF143. Funding Information: We thank Lene Hasmark Andersen for extracting DNA from soil samples. Melissa McCormick is thanked for providing information on suitable OMF primers and PCR conditions. Lea Vig McKinney helped screening seed packets for protocorms. We are grateful to Danish Nature Agency in Storstrøm for collaboration and access to field sites throughout the project. The project was supported by Godfred Birkedal Hartmanns Familiefond and infrastructure at the Center for Evolutionary Hologenomics was funded by the Danish National Research Foundation grant DNRF143. Publisher Copyright: © 2024 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

PY - 2024

Y1 - 2024

N2 - Plant–fungal interactions are ubiquitous across ecosystems and contribute significantly to plant ecology and evolution. All orchids form obligate symbiotic relationships with specific fungi for germination and early growth, and the distribution of terrestrial orchid species has been linked to occurrence and abundance of specific orchid mycorrhizal fungi (OMF) in the soil. The availability of OMF can therefore be a habitat requirement that is relevant to consider when establishing management and conservation strategies for threatened orchid species, but knowledge on the spatial distribution of OMF in soil is limited. We here studied the mycorrhizal associations of three terrestrial orchid species (Anacamptis pyramidalis, Orchis purpurea and Platanthera chlorantha) found in a local orchid diversity hotspot in eastern Denmark, and investigated the abundance of the identified mycorrhizal fungi in the surrounding soil. We applied ITS metabarcoding to samples of orchid roots, rhizosphere soil and bulk soil collected at three localities, supplemented with standard barcoding of root samples with OMF specific primers, and detected 22 Operational Taxonomic Units (OTUs) putatively identified as OMF. The three orchid species displayed different patterns of OMF associations, supporting the theory that association with specific fungi constitutes part of an orchid's ecological niche allowing co-occurrence of many species in orchid-rich habitats. The identified mycorrhizal partners in the basidiomycete families Tulasnellaceae and Ceratobasidiaceae (Cantharallales) were detected in low abundance in rhizosphere soil, and appeared almost absent from bulk soil at the localities. This finding highlights our limited knowledge of the ecology and trophic mode of OMF outside orchid tissues, as well as challenges in the detection of specific OMF with standard methods. Potential implications for management and conservation strategies are discussed.

AB - Plant–fungal interactions are ubiquitous across ecosystems and contribute significantly to plant ecology and evolution. All orchids form obligate symbiotic relationships with specific fungi for germination and early growth, and the distribution of terrestrial orchid species has been linked to occurrence and abundance of specific orchid mycorrhizal fungi (OMF) in the soil. The availability of OMF can therefore be a habitat requirement that is relevant to consider when establishing management and conservation strategies for threatened orchid species, but knowledge on the spatial distribution of OMF in soil is limited. We here studied the mycorrhizal associations of three terrestrial orchid species (Anacamptis pyramidalis, Orchis purpurea and Platanthera chlorantha) found in a local orchid diversity hotspot in eastern Denmark, and investigated the abundance of the identified mycorrhizal fungi in the surrounding soil. We applied ITS metabarcoding to samples of orchid roots, rhizosphere soil and bulk soil collected at three localities, supplemented with standard barcoding of root samples with OMF specific primers, and detected 22 Operational Taxonomic Units (OTUs) putatively identified as OMF. The three orchid species displayed different patterns of OMF associations, supporting the theory that association with specific fungi constitutes part of an orchid's ecological niche allowing co-occurrence of many species in orchid-rich habitats. The identified mycorrhizal partners in the basidiomycete families Tulasnellaceae and Ceratobasidiaceae (Cantharallales) were detected in low abundance in rhizosphere soil, and appeared almost absent from bulk soil at the localities. This finding highlights our limited knowledge of the ecology and trophic mode of OMF outside orchid tissues, as well as challenges in the detection of specific OMF with standard methods. Potential implications for management and conservation strategies are discussed.

KW - Ceratobasidiaceae

KW - ITS metabarcoding

KW - orchid mycorrhizal fungi

KW - plant hologenomics

KW - soil mycobiome

KW - Tulasnellaceae

U2 - 10.1002/ece3.10863

DO - 10.1002/ece3.10863

M3 - Journal article

C2 - 38304271

AN - SCOPUS:85183932446

VL - 14

JO - Ecology and Evolution

JF - Ecology and Evolution

SN - 2045-7758

IS - 2

M1 - e10863

ER -