A mixotrophy is in question: new data on fungal community associated with photosynthetic terrestrial orchid Goodyera repens

Mycoheterotrophic plants (MHPs) are leafless, achlorophyllous, and completely dependent on mycorrhizal fungi for their carbon supply. Mycorrhizal symbiosis is a mutualistic association with fungi that is undertaken by the majority of land plants, but mycoheterotrophy represents a breakdown of this mutualism in that plants parasitize fungi. Most MHPs are associated with fungi that are mycorrhizal with autotrophic plants, such as arbuscular mycorrhizal (AM) or ectomycorrhizal (ECM) fungi. Although these MHPs gain carbon via the common mycorrhizal network that links the surrounding autotrophic plants, some mycoheterotrophic lineages are associated with saprotrophic (SAP) fungi, which are free-living and decompose leaf litter and wood materials. Such MHPs are dependent on the forest carbon cycle, which involves the decomposition of wood debris and leaf litter, and have a unique biology and evolutionary history. MHPs associated with SAP fungi (SAP-MHPs) have to date been found only in the Orchidaceae and likely evolved independently at least nine times within that family. Phylogenetically divergent SAP Basidiomycota, mostly Agaricales but also Hymenochaetales, Polyporales, and others, are involved in mycoheterotrophy. The fungal specificity of SAP-MHPs varies from a highly specific association with a single fungal species to a broad range of interactions with multiple fungal orders. Establishment of symbiotic culture systems is indispensable for understanding the mechanisms underlying plant–fungus interactions and the conservation of MHPs. Symbiotic culture systems have been established for many SAP-MHP species as a pure culture of free-living SAP fungi is easier than that of biotrophic AM or ECM fungi. Culturable SAP-MHPs are useful research materials and will contribute to the advancement of plant science.

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“…(Fan et al 1996), Goodyera repens (L.) R.Br. (Voronina et al 2018), and Bletilla striata (Thunb.) Rchb.f.…”

Section: Evolution Of Mycorrhizal Interactionsunclassified

Evolutionary histories and mycorrhizal associations of mycoheterotrophic plants dependent on saprotrophic fungi

2021

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“…2 SUN 2011, three Rhizophagus , three R. intraradices , two R. irregularis , and an unknown Glomeromycota. Other studies have identified Glomus and Rhizophagus clarus (as Glomus clarum ) in Cypripedium californicum , and Funneliformis mosseae (as Glomus mosseae ) in C. parviflorum (Shefferson et al, 2005 ), as well as Glomus, Gigaspora, Scutellospora, Claroideoglomus and other likely AMF in other Orchidaceae (Gebauer and Meyer, 2003 ; Bidartondo et al, 2004 ; Voyron et al, 2017 ; Voronina et al, 2018 ). Notably, no AMF were unique to SS ash roots.…”

Section: Discussionmentioning

confidence: 97%

“…While achlorophyllous plants, including orchids, need an external source of energy throughout their life, the extent of mixotrophy, or partial nutritional dependence on fungi, in chlorophyllous orchids has been little investigated. Substantial evidence has accumulated to show that several Orchidaceae species that are chlorophyllous and photosynthetic as adults continue to obtain at least a part of their carbon energy from a shared, or common mycorrhizal network; Temperate orchid genera in which this has been documented include Cephalanthera, Epipactis (Bidartondo et al, 2004 ), Goodyera (Voronina et al, 2018 ), Listera (Gebauer and Meyer, 2003 ), Ophrys (Girlanda et al, 2011 ), and Rhizanthella (Warcup, 1985 ). Where the association is known, it is usually with ectomycorrhizal (ECM) fungi (Selosse et al, 2006 ), or with known root pathotrophic (Peschke and Volz, 1978 ; Vujanovic et al, 2000 ) or saprotrophic endophytes (Wang et al, 2021 ).…”

Section: Introductionmentioning

confidence: 99%

Multiple Fungi May Connect the Roots of an Orchid (Cypripedium reginae) and Ash (Fraxinus nigra) in Western Newfoundland

Weerasuriya

Kukolj

Spencer

et al. 2022

Front. Fungal Biol.

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Showy lady's slipper (Cypripedium reginae Walter, Orchidaceae) and black ash (Fraxinus nigra Marshall, Oleaceae) often co-occur in close proximity in fens in western Newfoundland, Canada. Metabarcoding of DNA extracted from root samples of both species following surface sterilization, and others without surface sterilization was used to determine if there were shared fungal endophytes in the roots of both species that could form a common mycorrhizal network between them. A wide variety of fungi were recovered from primers amplifying the nuclear ribosomal internal transcribed spacer region (ITS2). Sixty-six fungal sequences were shared by surface-sterilized roots of both orchid and ash, among them arbuscular mycorrhizal fungi (Claroideoglomus, Dominikia, Glomus and Rhizophagus), ectomycorrhizal fungi (Inocybe and Tomentella), the broad-host root endophyte Cadophora orchidicola, along with root pathogens (Dactylonectria, Ilyonectria, Pyricularia, and Xylomyces) and fungi of unknown function. There appear to be multiple fungi that could form a common mycorrhizal network between C. reginae and F. nigra, which might explain their frequent co-occurrence. Transfer of nutrients or carbon between the orchid and ash via one or more of the shared fungal endophytes remains to be demonstrated.

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“…Certain orchid species target other fungal groups that differ from usual OMF, with differences in the phylogenetic position and/or ecological traits [ 57 , 58 ]. Several groups of saprotrophic fungi, for example Mycena [ 59 ], Coprinellus [ 60 ], and Trametes [ 61 ], can colonize the roots of orchids and promote their growth or can serve as mycorrhizal fungi. Recent research suggests that mycorrhizal fungi could be recruited from the endophytic fungi colonized in orchid ancestors [ 57 ].…”

Section: Discussionmentioning

confidence: 99%

Coriolopsis strumosa as an Orchid Endophytic Fungus and Its Spatial Distribution in Epidendrum sp. (Orchidaceae)

Yao,

Wang,

Jiang

et al. 2024

Microorganisms

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Coriolopsis spp. are wood-decaying fungi that inhabit forests. They are mainly distributed in tropical and subtropical areas. Strain Epi910 was isolated from the asymbiotically germinated protocorm of Epidendrum sp. and identified as Coriolopsis strumosa. Symbiotic germination and high-throughput sequencing of the endophytic fungal communities of different parts were performed to characterize the function and spatial distribution of the Epi910 isolate. Under symbiotic germination, Epi910 promoted seed germination and seedling formation as an endophytic native fungus of Epidendrum sp. Endophytic fungal communities from seven different parts of Epidendrum sp. were characterized. In total, 645 OTUs were identified; 30 OTUs were shared among all seven parts. The internal transcribed spacer sequence of Epi910 was identical to that of a dominant shared OTU (OTU6). The relative abundance of OTU6 in the seven parts was identified as follows: capsule pericarp > seed > root > asymbiotically germinated protocorm > epiphytic root > ovary > rachis. Our results suggest that the isolate belonging to Coriolopsis strumosa could promote the germination of Epidendrum sp. There may, therefore, be endophytic fungi other than common orchid mycorrhizal fungi with the ability to enhance germination in orchids.

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A mixotrophy is in question: new data on fungal community associated with photosynthetic terrestrial orchid Goodyera repens

Cited by 6 publications

References 43 publications

Evolutionary histories and mycorrhizal associations of mycoheterotrophic plants dependent on saprotrophic fungi

Evolutionary histories and mycorrhizal associations of mycoheterotrophic plants dependent on saprotrophic fungi

Multiple Fungi May Connect the Roots of an Orchid (Cypripedium reginae) and Ash (Fraxinus nigra) in Western Newfoundland

Coriolopsis strumosa as an Orchid Endophytic Fungus and Its Spatial Distribution in Epidendrum sp. (Orchidaceae)

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