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Merckx VSFT, Gomes SIF, Wang D, Verbeek C, Jacquemyn H, Zahn FE, Gebauer G, Bidartondo MI. Mycoheterotrophy in the wood-wide web. NATURE PLANTS 2024; 10:710-718. [PMID: 38641664 DOI: 10.1038/s41477-024-01677-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 03/25/2024] [Indexed: 04/21/2024]
Abstract
The prevalence and potential functions of common mycorrhizal networks, or the 'wood-wide web', resulting from the simultaneous interaction of mycorrhizal fungi and roots of different neighbouring plants have been increasingly capturing the interest of science and society, sometimes leading to hyperbole and misinterpretation. Several recent reviews conclude that popular claims regarding the widespread nature of these networks in forests and their role in the transfer of resources and information between plants lack evidence. Here we argue that mycoheterotrophic plants associated with ectomycorrhizal or arbuscular mycorrhizal fungi require resource transfer through common mycorrhizal networks and thus are natural evidence for the occurrence and function of these networks, offering a largely overlooked window into this methodologically challenging underground phenomenon. The wide evolutionary and geographic distribution of mycoheterotrophs and their interactions with a broad phylogenetic range of mycorrhizal fungi indicate that common mycorrhizal networks are prevalent, particularly in forests, and result in net carbon transfer among diverse plants through shared mycorrhizal fungi. On the basis of the available scientific evidence, we propose a continuum of carbon transfer options within common mycorrhizal networks, and we discuss how knowledge on the biology of mycoheterotrophic plants can be instrumental for the study of mycorrhizal-mediated transfers between plants.
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Affiliation(s)
- Vincent S F T Merckx
- Understanding Evolution, Naturalis Biodiversity Center, Leiden, the Netherlands.
- Evolutionary and Population Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands.
| | - Sofia I F Gomes
- Above-belowground Interactions, Institute of Biology Leiden, Leiden University, Leiden, the Netherlands
| | - Deyi Wang
- Understanding Evolution, Naturalis Biodiversity Center, Leiden, the Netherlands
| | - Cas Verbeek
- Understanding Evolution, Naturalis Biodiversity Center, Leiden, the Netherlands
- Evolutionary and Population Biology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands
| | - Hans Jacquemyn
- Plant Population Biology and Conservation, Department of Biology, Plant Conservation and Population Biology, KU Leuven, Leuven, Belgium
| | - Franziska E Zahn
- Laboratory of Isotope Biogeochemistry, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Bayreuth, Germany
| | - Gerhard Gebauer
- Laboratory of Isotope Biogeochemistry, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Bayreuth, Germany
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Yagame T, Figura T, Tanaka E, Selosse MA, Yukawa T. Mycobiont identity and light conditions affect belowground morphology and physiology of a mixotrophic orchid Cremastra variabilis (Orchidaceae). MYCORRHIZA 2024; 34:19-31. [PMID: 38381148 DOI: 10.1007/s00572-024-01138-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 02/12/2024] [Indexed: 02/22/2024]
Abstract
We have investigated whether mycobiont identity and environmental conditions affect morphology and physiology of the chlorophyllous orchid: Cremastra variabilis. This species grows in a broad range of environmental conditions and associates with saprotrophic rhizoctonias including Tulasnellaceae and saprotrophic non-rhizoctonian fungi from the family Psathyrellaceae. We cultured the orchid from seeds under aseptic culture conditions and subsequently inoculated the individuals with either a Tulasnellaceae or a Psathyrellaceae isolate. We observed underground organ development of the inoculated C. variabilis plants and estimated their nutritional dependency on fungi using stable isotope abundance. Coralloid rhizome development was observed in all individuals inoculated with the Psathyrellaceae isolate, and 1-5 shoots per seedling grew from the tip of the coralloid rhizome. In contrast, individuals associated with the Tulasnellaceae isolate did not develop coralloid rhizomes, and only one shoot emerged per plantlet. In darkness, δ13C enrichment was significantly higher with both fungal isolates, whereas δ15N values were only significantly higher in plants associated with the Psathyrellaceae isolate. We conclude that C. variabilis changes its nutritional dependency on fungal symbionts depending on light availability and secondly that the identity of fungal symbiont influences the morphology of underground organs.
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Affiliation(s)
- Takahiro Yagame
- The Mt. Fuji Institute for Nature and Biology, Showa University, 4562 Kamiyoshida, Fujiyoshida, Yamashi, 403-0005, Japan.
- Division of Academic Resources and Specimens, Hokkaido University Museum, Kita 10-jo, Nishi 8-chome, Kita-ku, Sapporo, Hokkaido, 060-0810, Japan.
| | - Tomáš Figura
- Department of Mycorrhizal Symbioses, Institute of Botany, Czech Academy of Sciences, Lesní 322, 25243, Průhonice, Czechia
- Naturalis Biodiversity Center, Darwinweg 2, 2333 CR, Leiden, The Netherlands
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, CP, 39, 57 rue Cuvier, F-75005, Paris, France
| | - Eiji Tanaka
- Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, 921-8836, Japan
| | - Marc-André Selosse
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, CP, 39, 57 rue Cuvier, F-75005, Paris, France
- University of Gdańsk, Faculty of Biology, Department of Vertebrate Ecology and Zoology; ul. Wita Stwosza 59, 80-308, Gdańsk, Poland
- Institut Universitaire de France, Paris, France
| | - Tomohisa Yukawa
- Tsukuba Botanical Garden, National Museum of Nature and Science, 4-1-1, Amakubo, Tsukuba, Ibaraki, 305-0005, Japan
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Suetsugu K, Ohta T, Tayasu I. Partial mycoheterotrophy in the leafless orchid Eulophia zollingeri specialized on wood-decaying fungi. MYCORRHIZA 2024; 34:33-44. [PMID: 38520554 DOI: 10.1007/s00572-024-01136-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 02/01/2024] [Indexed: 03/25/2024]
Abstract
Although the absence of normal leaves is often considered a sign of full heterotrophy, some plants remain at least partially autotrophic despite their leafless habit. Leafless orchids with green stems and capsules probably represent a late evolutionary stage toward full mycoheterotrophy and serve as valuable models for understanding the pathways leading to this nutritional strategy. In this study, based on molecular barcoding and isotopic analysis, we explored the physiological ecology of the leafless orchid Eulophia zollingeri, which displays green coloration, particularly during its fruiting phase. Although previous studies had shown that E. zollingeri, in its adult stage, is associated with Psathyrellaceae fungi and exhibits high 13C isotope signatures similar to fully mycoheterotrophic orchids, it remained uncertain whether this symbiotic relationship is consistent throughout the orchid's entire life cycle and whether the orchid relies exclusively on mycoheterotrophy for its nutrition during the fruiting season. Our study has demonstrated that E. zollingeri maintains a specialized symbiotic relationship with Psathyrellaceae fungi throughout all life stages. However, isotopic analysis and chlorophyll data have shown that the orchid also engages in photosynthesis to meet its carbon needs, particularly during the fruiting stage. This research constitutes the first discovery of partial mycoheterotrophy in leafless orchids associated with saprotrophic non-rhizoctonia fungi.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Hyogo, 657-8501, Japan.
- Institute for Advanced Research, Kobe University, 1-1 Rokkodai, Nada-Ku, Kobe, Hyogo, 657-8501, Japan.
| | - Tamihisa Ohta
- Faculty of Science, Academic Assembly, University of Toyama, Gofuku 3190, Toyama, 930-8555, Japan
| | - Ichiro Tayasu
- Research Institute for Humanity and Nature, 457-4 Motoyama Kamigamo, Kita-Ku, Kyoto, 603-8047, Japan
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Baan J, Holloway-Phillips M, Nelson DB, Kahmen A. The metabolic sensitivity of hydrogen isotope fractionation differs between plant compounds. PHYTOCHEMISTRY 2023; 207:113563. [PMID: 36528118 DOI: 10.1016/j.phytochem.2022.113563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 12/10/2022] [Accepted: 12/11/2022] [Indexed: 06/17/2023]
Abstract
Hydrogen stable isotope analyses (δ2H) of plant derived organic compounds are a useful tool for ecological, environmental, and palaeoclimatological research. However, during organic compound synthesis, variable biosynthetic 2H-fractionation has been suggested to occur as a result of changes in plant carbon fluxes. So far, inference has been based on examining the δ2H patterns of plant compounds along environmental gradients, among plant species, and between plant organs. In an alternative approach, we used four plant species with four different types of mutations that cause impaired starch synthesis to assess whether variability in carbon metabolism affects the biosynthetic 2H-fractionation during cellulose, phytol, and acetogenic lipid synthesis. We found that mutants with impaired starch synthesis always had higher cellulose and phytol δ2H values compared to the wild type. By contrast, 2H-fractionation during acetogenic lipid biosynthesis generally did not show strong metabolic sensitivity. We rationalise these differences by considering the biosynthetic pathway of each compound and the likely source of the variable isotope fractionation. In different organic compounds, the sensitivity of variable biosynthetic 2H-fractionation to changes in C-metabolism depends on incorporation of specific H atoms from precursor molecules. As such, we determined that the similar increase in cellulose and phytol δ2H values as an effect of impaired starch synthesis most likely originates in triose-phosphates.
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Affiliation(s)
- Jochem Baan
- University of Basel, Department of Environmental Sciences - Botany, Schönbeinstrasse 6, 4056, Basel, Switzerland.
| | - Meisha Holloway-Phillips
- University of Basel, Department of Environmental Sciences - Botany, Schönbeinstrasse 6, 4056, Basel, Switzerland
| | - Daniel B Nelson
- University of Basel, Department of Environmental Sciences - Botany, Schönbeinstrasse 6, 4056, Basel, Switzerland
| | - Ansgar Kahmen
- University of Basel, Department of Environmental Sciences - Botany, Schönbeinstrasse 6, 4056, Basel, Switzerland
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Novotná A, Mennicken S, de Paula CCP, Vogt-Schilb H, Kotilínek M, Těšitelová T, Šmilauer P, Jersáková J. Variability in Nutrient Use by Orchid Mycorrhizal Fungi in Two Medium Types. J Fungi (Basel) 2023; 9:jof9010088. [PMID: 36675907 PMCID: PMC9865426 DOI: 10.3390/jof9010088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/28/2022] [Accepted: 01/03/2023] [Indexed: 01/07/2023] Open
Abstract
Orchid mycorrhizal fungi (OMF) from the rhizoctonia aggregate are generally considered to be soil saprotrophs, but their ability to utilize various nutrient sources has been studied in a limited number of isolates cultivated predominantly in liquid media, although rhizoctonia typically grow on the surface of solid substrates. Nine isolates representing the key OMF families (Ceratobasidiaceae, Tulasnellaceae and Serendipitaceae), sampled in Southern France and the Czech Republic, were tested for their ability to utilize carbon (C), nitrogen (N) and phosphorus (P) sources in vitro in both liquid and solid media. The isolates showed significant inter- and intra-familiar variability in nutrient utilization, most notably in N sources. Isolates produced generally larger amounts of dry biomass on solid medium than in liquid one, but some isolates showed no or limited biomass production on solid medium with particular nutrient sources. The largest amount of biomass was produced by isolates from the family Ceratobasidiaceae on most sources in both medium types. The biomass production of Tulasnellaceae isolates was affected by their phylogenetic relatedness on all sources and medium types. The ability of isolates to utilize particular nutrients in a liquid medium but not a solid one should be considered when optimizing solid media for symbiotic orchid seed germination and in understanding of OMF functional traits under in situ conditions.
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Affiliation(s)
- Alžběta Novotná
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - Sophie Mennicken
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - Caio C. Pires de Paula
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
- Institute of Hydrobiology, Biology Centre CAS, Na Sádkách 702/7, 37005 České Budějovice, Czech Republic
| | - Hélène Vogt-Schilb
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
- Centre d’Écologie Fonctionnelle et Évolutive, Centre National de la Recherche Scientifique, University of Montpellier, EPHE, IRD, 1919 Route de Mende, 34293 Montpellier, France
| | - Milan Kotilínek
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - Tamara Těšitelová
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - Petr Šmilauer
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
| | - Jana Jersáková
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia, Branišovská 1760, 37005 České Budějovice, Czech Republic
- Correspondence:
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McCormick MK, Good KL, Mozdzer TJ, Whigham DF. Shade and drought increase fungal contribution to partially mycoheterotrophic terrestrial orchids Goodyera pubescens and Tipularia discolor. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1047267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Many photosynthetic plants supplement photosynthetic carbon with fungal carbon, but the mechanisms that govern dependence on mycoheterotrophic carbon are poorly understood. We used exclusion shelters to manipulate water and light availability to plants of the terrestrial orchids Goodyera pubescens and Tipularia discolor. We tracked changes in δ13C from photosynthesis and δ15N acquired from soil-derived inorganic nitrogen versus mycoheterotrophy, along with direct measures of photosynthesis in T. discolor. We hypothesized that shade would increase dependence on mycoheterotrophy compared to reference plants, while drought would decrease both photosynthesis and the abundance of potential mycorrhizal fungi. Drought and shade enriched 13C and 15N in both G. pubescens and T. discolor, compared to control plants, indicating increased fungal contribution to orchid tissues. Physiological measurements of T. discolor leaves showed that dark respiration, water use efficiency, and relative electron transport rate did not vary significantly, but shaded plants had greater quantum efficiency, suggesting they were light-limited. Light saturated photosynthesis of T. discolor leaves was lower in both shaded and drought-treated plants, indicating lower photosynthetic capacity, and likely greater dependence on mycoheterotrophy and corresponding enrichment in 13C and 15N. This study documented changes in orchid dependence on fungal carbon in response to manipulated environmental conditions. Both shade and drought increased the dependence of both orchids on mycoheterotrophically derived carbon and nitrogen.
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Suetsugu K, Matsubayashi J. Foliar chlorophyll concentration modulates the degree of fungal exploitation in a rhizoctonia-associated orchid. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:4204-4213. [PMID: 35312761 DOI: 10.1093/jxb/erac124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
Some green orchids obtain carbon from both mycobionts and photosynthesis at the adult stage. Intriguingly, these orchids can produce albino and, in rare cases, variegated phenotypes. Here, we studied a Platanthera hondoensis population with green, variegated, and albino individuals. Although its closely related Platanthera species are usually associated with non-ectomycorrhizal rhizoctonias, and several studies have failed to find evidence of trophic plasticity in rhizoctonia-associated orchids, variegated and albino P. hondoensis must possess a higher fungal dependency than green P. hondoensis. Therefore, we investigated whether (i) P. hondoensis is associated with non-ectomycorrhizal rhizoctonias and (ii) the degree of mycoheterotrophy (using 13C abundance as a proxy) correlates with the foliar chlorophyll concentration. High-throughput DNA sequencing revealed that all P. hondoensis phenotypes were dominantly associated with a rhizoctonia from Ceratobasidiaceae belonging to a clade distinct from recognized ectomycorrhizal clades. Regression analysis revealed a positive linear relationship between foliar chlorophyll concentration and the degree of mycoheterotrophy. This study strongly suggests that rhizoctonia-associated P. hondoensis can dynamically adjust fungal exploitation in response to photosynthetic carbon levels. Since rhizoctonia is the most common orchid mycorrhizal partner, trophic plasticity may be a widespread adaptive trait in green orchids.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Jun Matsubayashi
- Department of Integrated Science and Engineering for Sustainable Societies, Faculty of Science and Engineering, Chuo University, Tokyo, Japan
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Zahn FE, Lee YI, Gebauer G. Fungal association and root morphology shift stepwise during ontogenesis of orchid Cremastra appendiculata towards autotrophic nutrition. AOB PLANTS 2022; 14:plac021. [PMID: 35673361 PMCID: PMC9167560 DOI: 10.1093/aobpla/plac021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
The chlorophyllous, terrestrial orchid Cremastra appendiculata from East Asia is unique concerning its fungal mycorrhiza partners. The initially mycoheterotrophic protocorms exploit rather specialized non-rhizoctonia saprotrophic Psathyrellaceae. Adult individuals of this orchid species are either linked to Psathyrellaceae being partially mycoheterotrophic or form mycorrhiza with fungi of the ubiquitous saprotrophic rhizoctonia group. This study provides new insights on nutrition mode, subterranean morphology and fungal partners across different life stages of C. appendiculata. We compared different development stages of C. appendiculata to surrounding autotrophic reference plants based on multi-element natural abundance stable isotope analyses (δ13C, δ15N, δ2H, δ18O) and total N concentrations. Site- and sampling-time-independent enrichment factors of stable isotopes were used to reveal trophic strategies. We determined mycorrhizal fungi of C. appendiculata protocorm, seedling and adult samples using high-throughput DNA sequencing. We identified saprotrophic non-rhizoctonia Psathyrellaceae as dominant mycorrhizal fungi in protocorm and seedling rhizomes. In contrast, the roots of seedlings and mature C. appendiculata were mainly colonized with fungi belonging to the polyphyletic assembly of rhizoctonia (Ceratobasidium, Thanatephorus and Serendipitaceae). Mature C. appendiculata did not differ in isotopic signature from autotrophic reference plants suggesting a fully autotrophic nutrition mode. Characteristic of orchid specimens entirely relying on fungal nutrition, C. appendiculata protocorms were enriched in 15N, 13C and 2H compared to reference plants. Seedlings showed an intermediate isotopic signature, underpinning the differences in the fungal community depending on their subterranean morphology. In contrast to the suggestion that C. appendiculata is a partially mycoheterotrophic orchid species, we provide novel evidence that mature C. appendiculata with rhizoctonia mycobionts can be entirely autotrophic. Besides an environmentally driven variability among populations, we suggest high within-individual flexibility in nutrition and mycobionts of C. appendiculata, which is subject to the ontogenetic development stage.
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Affiliation(s)
- Franziska E Zahn
- Laboratory of Isotope Biogeochemistry, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
| | - Yung-I Lee
- Department of Life Science, National Taiwan University, Taipei 10617, Taiwan
- Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei 10617, Taiwan
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'Fly to a Safer North': Distributional Shifts of the Orchid Ophrys insectifera L. Due to Climate Change. BIOLOGY 2022; 11:biology11040497. [PMID: 35453696 PMCID: PMC9025215 DOI: 10.3390/biology11040497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/15/2022] [Accepted: 03/22/2022] [Indexed: 12/10/2022]
Abstract
Numerous orchid species around the world have already been affected by the ongoing climate change, displaying phenological alterations and considerable changes to their distributions. The fly orchid (Ophrys insectifera L.) is a well-known and distinctive Ophrys species in Europe, with a broad distribution across the continent. This study explores the effects of climate change on the range of O. insectifera, using a species distribution models (SDMs) framework that encompasses different climatic models and scenarios for the near- and long-term future. The species' environmentally suitable area is projected to shift northwards (as expected) but downhill (contrary to usual expectations) in the future. In addition, an overall range contraction is predicted under all investigated combinations of climatic models and scenarios. While this is moderate overall, it includes some regions of severe loss and other areas with major gains. Specifically, O. insectifera is projected to experience major area loss in its southern reaches (the Balkans, Italy and Spain), while it will expand its northern limits to North Europe, with the UK, Scandinavia, and the Baltic countries exhibiting the largest gains.
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Selosse MA, Petrolli R, Mujica MI, Laurent L, Perez-Lamarque B, Figura T, Bourceret A, Jacquemyn H, Li T, Gao J, Minasiewicz J, Martos F. The Waiting Room Hypothesis revisited by orchids: were orchid mycorrhizal fungi recruited among root endophytes? ANNALS OF BOTANY 2022; 129:259-270. [PMID: 34718377 PMCID: PMC8835631 DOI: 10.1093/aob/mcab134] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 10/25/2021] [Indexed: 05/17/2023]
Abstract
BACKGROUND As in most land plants, the roots of orchids (Orchidaceae) associate with soil fungi. Recent studies have highlighted the diversity of the fungal partners involved, mostly within Basidiomycotas. The association with a polyphyletic group of fungi collectively called rhizoctonias (Ceratobasidiaceae, Tulasnellaceae and Serendipitaceae) is the most frequent. Yet, several orchid species target other fungal taxa that differ from rhizoctonias by their phylogenetic position and/or ecological traits related to their nutrition out of the orchid roots (e.g. soil saprobic or ectomycorrhizal fungi). We offer an evolutionary framework for these symbiotic associations. SCOPE Our view is based on the 'Waiting Room Hypothesis', an evolutionary scenario stating that mycorrhizal fungi of land flora were recruited from ancestors that initially colonized roots as endophytes. Endophytes biotrophically colonize tissues in a diffuse way, contrasting with mycorrhizae by the absence of morphological differentiation and of contribution to the plant's nutrition. The association with rhizoctonias is probably the ancestral symbiosis that persists in most extant orchids, while during orchid evolution numerous secondary transitions occurred to other fungal taxa. We suggest that both the rhizoctonia partners and the secondarily acquired ones are from fungal taxa that have broad endophytic ability, as exemplified in non-orchid roots. We review evidence that endophytism in non-orchid plants is the current ecology of many rhizoctonias, which suggests that their ancestors may have been endophytic in orchid ancestors. This also applies to the non-rhizoctonia fungi that were secondarily recruited by several orchid lineages as mycorrhizal partners. Indeed, from our review of the published literature, they are often detected, probably as endophytes, in extant rhizoctonia-associated orchids. CONCLUSION The orchid family offers one of the best documented examples of the 'Waiting Room Hypothesis': their mycorrhizal symbioses support the idea that extant mycorrhizal fungi have been recruited among endophytic fungi that colonized orchid ancestors.
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Affiliation(s)
- Marc-André Selosse
- Institut de Systématique, Évolution, Biodiversité (UMR 7205 – CNRS, MNHN, UPMC, EPHE), Muséum national d’Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, 75005 Paris, France
- Department of Plant Taxonomy and Nature Conservation, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, China
| | - Rémi Petrolli
- Institut de Systématique, Évolution, Biodiversité (UMR 7205 – CNRS, MNHN, UPMC, EPHE), Muséum national d’Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, 75005 Paris, France
| | - María Isabel Mujica
- Institut de Systématique, Évolution, Biodiversité (UMR 7205 – CNRS, MNHN, UPMC, EPHE), Muséum national d’Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, 75005 Paris, France
- Departamento de Ecología, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile, & Instituto de Ecología and Biodiversidad (IEB), Alameda 340, Santiago, Chile
| | - Liam Laurent
- Institut de Systématique, Évolution, Biodiversité (UMR 7205 – CNRS, MNHN, UPMC, EPHE), Muséum national d’Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, 75005 Paris, France
| | - Benoît Perez-Lamarque
- Institut de Systématique, Évolution, Biodiversité (UMR 7205 – CNRS, MNHN, UPMC, EPHE), Muséum national d’Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, 75005 Paris, France
- Institut de Biologie de l’École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, 46 rue d’Ulm, 75005 Paris, France
| | - Tomáš Figura
- Institut de Systématique, Évolution, Biodiversité (UMR 7205 – CNRS, MNHN, UPMC, EPHE), Muséum national d’Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, 75005 Paris, France
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Viničná 5, 128 44, Prague, Czech Republic
| | - Amelia Bourceret
- Institut de Systématique, Évolution, Biodiversité (UMR 7205 – CNRS, MNHN, UPMC, EPHE), Muséum national d’Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, 75005 Paris, France
| | - Hans Jacquemyn
- Department of Biology, Plant Conservation and Population Biology, Department of Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Taiqiang Li
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, China
| | - Jiangyun Gao
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, China
| | - Julita Minasiewicz
- Department of Plant Taxonomy and Nature Conservation, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Florent Martos
- Institut de Systématique, Évolution, Biodiversité (UMR 7205 – CNRS, MNHN, UPMC, EPHE), Muséum national d’Histoire naturelle, Sorbonne Universités, 57 rue Cuvier, 75005 Paris, France
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11
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Ponert J, Šoch J, Vosolsobě S, Čiháková K, Lipavská H. Integrative Study Supports the Role of Trehalose in Carbon Transfer From Fungi to Mycotrophic Orchid. FRONTIERS IN PLANT SCIENCE 2021; 12:793876. [PMID: 34956293 PMCID: PMC8695678 DOI: 10.3389/fpls.2021.793876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/15/2021] [Indexed: 05/08/2023]
Abstract
Orchids rely on mycorrhizal symbiosis, especially in the stage of mycoheterotrophic protocorms, which depend on carbon and energy supply from fungi. The transfer of carbon from fungi to orchids is well-documented, but the identity of compounds ensuring this transfer remains elusive. Some evidence has been obtained for the role of amino acids, but there is also vague and neglected evidence for the role of soluble carbohydrates, probably trehalose, which is an abundant fungal carbohydrate. We therefore focused on the possible role of trehalose in carbon and energy transfer. We investigated the common marsh orchid (Dactylorhiza majalis) and its symbiotic fungus Ceratobasidium sp. using a combination of cultivation approaches, high-performance liquid chromatography, application of a specific inhibitor of the enzyme trehalase, and histochemical localization of trehalase activity. We found that axenically grown orchid protocorms possess an efficient, trehalase-dependent, metabolic pathway for utilizing exogenous trehalose, which can be as good a source of carbon and energy as their major endogenous soluble carbohydrates. This is in contrast to non-orchid plants that cannot utilize trehalose to such an extent. In symbiotically grown protocorms and roots of adult orchids, trehalase activity was tightly colocalized with mycorrhizal structures indicating its pronounced role in the mycorrhizal interface. Inhibition of trehalase activity arrested the growth of both symbiotically grown protocorms and trehalose-supported axenic protocorms. Since trehalose constitutes only an inconsiderable part of the endogenous saccharide spectrum of orchids, degradation of fungal trehalose likely takes place in orchid mycorrhiza. Our results strongly support the neglected view of the fungal trehalose, or the glucose produced by its cleavage as compounds transported from fungi to orchids to ensure carbon and energy flow. Therefore, we suggest that not only amino acids, but also soluble carbohydrates are transported. We may propose that the soluble carbohydrates would be a better source of energy for plant metabolism than amino acids, which is partially supported by our finding of the essential role of trehalase.
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Affiliation(s)
- Jan Ponert
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
- Prague Botanical Garden, Prague, Czechia
- Institute of Botany, Czech Academy of Sciences, Průhonice, Czechia
| | - Jan Šoch
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Stanislav Vosolsobě
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Klára Čiháková
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Helena Lipavská
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
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12
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Yagame T, Lallemand F, Selosse MA, Funabiki E, Yukawa T. Mycobiont diversity and first evidence of mixotrophy associated with Psathyrellaceae fungi in the chlorophyllous orchid Cremastra variabilis. JOURNAL OF PLANT RESEARCH 2021; 134:1213-1224. [PMID: 34405353 DOI: 10.1007/s10265-021-01337-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Mixotrophy (MX, also called partial mycoheterotrophy) in plants is characterized by isotopic abundances that differ from those of autotrophs. Previous studies have evaluated mycoheterotrophy in MX plants associated with fungi of similar ecological characteristics, but little is known about the differences in the relative abundances of 13C and 15N in an orchid species that associates with several different mycobionts species. Since the chlorophyllous orchid Cremastra variabilis Nakai associates with various fungi with different ecologies, we hypothesized that it may change its relative abundances of 13C and 15N depending on the associated mycobionts. We investigated mycobiont diversity in the chlorophyllous orchid C. variabilis together with the relative abundance of 13C and 15N and morphological underground differentiation (presence or absence of a mycorhizome with fungal colonization). Rhizoctonias (Tulasnellaceae, Ceratobasidiaceae, Sebacinales) were detected as the main mycobionts. High differences in δ13C values (- 34.7 to - 27.4 ‰) among individuals were found, in which the individuals associated with specific Psathyrellaceae showed significantly high relative abundance of 13C. In addition, Psathyrellaceae fungi were always detected on individuals with mycorhizomes. In the present study, MX orchid association with non-rhizoctonia saprobic fungi was confirmed, and the influence of mycobionts on morphological development and on relative abundance of 13C and 15N was discovered. Cremastra variabilis may increase opportunities to gain nutrients from diverse partners, in a bet-hedging plasticity that allows colonization of various environmental conditions.
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Affiliation(s)
- Takahiro Yagame
- Mizuho Town Museum, 316-5 Komagata Fujiyama, Mizuho, Nishitama, Tokyo, Japan.
| | - Felix Lallemand
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, CP 39, 57 rue Cuvier, 75005, Paris, France
| | - Marc-André Selosse
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire Naturelle, CNRS, Sorbonne Université, EPHE, Université des Antilles, CP 39, 57 rue Cuvier, 75005, Paris, France
- Department of Plant Taxonomy and Nature Conservation, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Eriko Funabiki
- The Graduate School of Agricultural Sciences, Tottori University, 4-101 Koyama-minami, Tottori, 680-8553, Japan
| | - Tomohisa Yukawa
- Tsukuba Botanical Garden, National Museum of Nature and Science, 4-1-1, Amakubo, Tsukuba, Ibaraki, 305-0005, Japan
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13
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Suetsugu K, Haraguchi TF, Okada H, Tayasu I. Stigmatodactylus sikokianus (Orchidaceae) mainly acquires carbon from decaying litter through association with a specific clade of Serendipitaceae. THE NEW PHYTOLOGIST 2021; 231:1670-1675. [PMID: 34076261 DOI: 10.1111/nph.17523] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/27/2021] [Indexed: 06/12/2023]
Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Hyogo, 657-8501, Japan
| | - Takashi F Haraguchi
- Research Institute for Humanity and Nature, Kita-ku, Kyoto, 603-8047, Japan
- Biodiversity Research Center, Research Institute of Environment, Agriculture and Fisheries, Osaka Prefecture, 10-4 Koyamotomachi, Neyagawa, Osaka, 572-0088, Japan
| | - Hidehito Okada
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Hyogo, 657-8501, Japan
| | - Ichiro Tayasu
- Research Institute for Humanity and Nature, Kita-ku, Kyoto, 603-8047, Japan
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14
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Berry EJ, Cleavitt NL. Population dynamics and comparative demographics in sympatric populations of the round‐leaved orchids
Platanthera macrophylla
and
P. orbiculata. POPUL ECOL 2021. [DOI: 10.1002/1438-390x.12092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Eric J. Berry
- Biology Department St. Anselm College Manchester New Hampshire USA
| | - Natalie L. Cleavitt
- Department of Natural Resources and the Environment, Fernow Hall Cornell University Ithaca New York USA
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15
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Li T, Yang W, Wu S, Selosse MA, Gao J. Progress and Prospects of Mycorrhizal Fungal Diversity in Orchids. FRONTIERS IN PLANT SCIENCE 2021; 12:646325. [PMID: 34025694 PMCID: PMC8138444 DOI: 10.3389/fpls.2021.646325] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 04/12/2021] [Indexed: 05/03/2023]
Abstract
Orchids form mycorrhizal symbioses with fungi in natural habitats that affect their seed germination, protocorm growth, and adult nutrition. An increasing number of studies indicates how orchids gain mineral nutrients and sometime even organic compounds from interactions with orchid mycorrhizal fungi (OMF). Thus, OMF exhibit a high diversity and play a key role in the life cycle of orchids. In recent years, the high-throughput molecular identification of fungi has broadly extended our understanding of OMF diversity, revealing it to be a dynamic outcome co-regulated by environmental filtering, dispersal restrictions, spatiotemporal scales, biogeographic history, as well as the distribution, selection, and phylogenetic spectrum width of host orchids. Most of the results show congruent emerging patterns. Although it is still difficult to extend them to all orchid species or geographical areas, to a certain extent they follow the "everything is everywhere, but the environment selects" rule. This review provides an extensive understanding of the diversity and ecological dynamics of orchid-fungal association. Moreover, it promotes the conservation of resources and the regeneration of rare or endangered orchids. We provide a comprehensive overview, systematically describing six fields of research on orchid-fungal diversity: the research methods of orchid-fungal interactions, the primer selection in high-throughput sequencing, the fungal diversity and specificity in orchids, the difference and adaptability of OMF in different habitats, the comparison of OMF in orchid roots and soil, and the spatiotemporal variation patterns of OMF. Further, we highlight certain shortcomings of current research methodologies and propose perspectives for future studies. This review emphasizes the need for more information on the four main ecological processes: dispersal, selection, ecological drift, and diversification, as well as their interactions, in the study of orchid-fungal interactions and OMF community structure.
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Affiliation(s)
- Taiqiang Li
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, China
| | - Wenke Yang
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, China
| | - Shimao Wu
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, China
| | - Marc-André Selosse
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, China
- Institut de Systématique, Évolution, Biodiversité, UMR 7205, CNRS, MNHN, UPMC, EPHE, Muséum National d’Histoire Naturelle, Sorbonne Universités, Paris, France
- Department of Plant Taxonomy and Nature Conservation, Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Jiangyun Gao
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology, Yunnan University, Kunming, China
- Laboratory of Ecology and Evolutionary Biology, Yunnan University, Kunming, China
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16
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Suetsugu K, Yamato M, Matsubayashi J, Tayasu I. Partial and full mycoheterotrophy in green and albino phenotypes of the slipper orchid Cypripedium debile. MYCORRHIZA 2021; 31:301-312. [PMID: 33852063 DOI: 10.1007/s00572-021-01032-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
Most green orchids form mycorrhizal associations with rhizoctonia fungi, a polyphyletic group including Serendipitaceae, Ceratobasidiaceae, and Tulasnellaceae. Although accumulating evidence indicated that partial mycoheterotrophy occurs in such so-called rhizoctonia-associated orchids, it remains unclear how much nutrition rhizoctonia-associated orchids obtain via mycoheterotrophic relationships. We investigated the physiological ecology of green and albino individuals of a rhizoctonia-associated orchid Cypripedium debile, by using molecular barcoding of the mycobionts and stable isotope (13C and 15 N) analysis. Molecular barcoding of the mycobionts indicated that the green and albino individuals harbored Tulasnella spp., which formed a clade with the previously reported C. debile mycobionts. In addition, stable isotope analysis showed that both phenotypes were significantly enriched in 13C but not in 15 N. Therefore, green and albino individuals were recognized as partial and full mycoheterotrophs, respectively. The green variants were estimated to obtain 42.5 ± 8.2% of their C from fungal sources, using the 13C enrichment factor of albino individuals as a mycoheterotrophic endpoint. The proportion of fungal-derived C in green C. debile was higher than that reported in other rhizoctonia-associated orchids. The high fungal dependence may facilitate the emergence of albino mutants. Our study provides the first evidence of partial mycoheterotrophy in the subfamily Cypripedioideae. Partial mycoheterotrophy may be more general than previously recognized in the family Orchidaceae.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan.
| | | | - Jun Matsubayashi
- Department of Biogeochemistry Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan
| | - Ichiro Tayasu
- Research Institute for Humanity and Nature, Kita-ku, Kyoto, Japan
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17
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Suetsugu K, Haraguchi TF, Tanabe AS, Tayasu I. Specialized mycorrhizal association between a partially mycoheterotrophic orchid Oreorchis indica and a Tomentella taxon. MYCORRHIZA 2021; 31:243-250. [PMID: 33150532 DOI: 10.1007/s00572-020-00999-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 10/21/2020] [Indexed: 05/25/2023]
Abstract
The evolution of full mycoheterotrophy in orchids likely occurs through intermediate stages (i.e., partial mycoheterotrophy or mixotrophy), in which adult plants obtain nutrition through both autotrophy and mycoheterotrophy. However, because of its cryptic manifestation, partial mycoheterotrophy has only been confirmed in slightly more than 20 orchid species. Here, we hypothesized that Oreorchis indica is partially mycoheterotrophic, since (i) Oreorchis is closely related to leafless Corallorhiza, and (ii) it possesses clustered, multi-branched rhizomes that are often found in fully mycoheterotrophic orchids. Accordingly, we investigated the nutritional modes of O. indica in a Japanese subboreal forest by measuring the 13C and 15N abundances and by community profiling of its mycorrhizal fungi. We found that O. indica mycorrhizal samples (all 12 samples from four individuals) were predominantly colonized by a single OTU of the obligate ectomycorrhizal Tomentella (Thelephoraceae). In addition, the leaves of O. indica were highly enriched in both 13C and 15N compared with those of co-occurring autotrophic plants. It was estimated that O. indica obtained 44.4 ± 6.2% of its carbon from fungal sources. These results strongly suggest that in the Oreorchis-Corallorhiza clade, full mycoheterotrophy evolved after the establishment of partial mycoheterotrophy, rather than through direct shifts from autotrophy.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Hyogo, 657-8501, Japan.
| | - Takashi F Haraguchi
- Research Institute for Humanity and Nature, Kita-ku, Kyoto, 603-8047, Japan
- Biodiversity Research Center, Research Institute of Environment, Agriculture and Fisheries, Osaka Prefecture, 10-4 Koyamotomachi, Osaka, 572-0088, Neyagawa, Japan
| | - Akifumi S Tanabe
- Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8578, Japan
| | - Ichiro Tayasu
- Research Institute for Humanity and Nature, Kita-ku, Kyoto, 603-8047, Japan
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18
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Jacquemyn H, Brys R, Waud M, Evans A, Figura T, Selosse MA. Mycorrhizal Communities and Isotope Signatures in Two Partially Mycoheterotrophic Orchids. FRONTIERS IN PLANT SCIENCE 2021; 12:618140. [PMID: 33633765 PMCID: PMC7901878 DOI: 10.3389/fpls.2021.618140] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/18/2021] [Indexed: 05/20/2023]
Abstract
Partial mycoheterotrophy, the ability of plants to obtain carbon from fungi throughout their life cycle in combination with photosynthesis, appears to be more common within the Plant Kingdom than previously anticipated. Recent studies using stable isotope analyses have indicated that isotope signatures in partially mycoheterotrophic plants vary widely among species, but the relative contributions of family- or species-specific characteristics and the identity of the fungal symbionts to the observed differences remain unclear. Here, we investigated in detail mycorrhizal communities and isotopic signatures in four co-occurring terrestrial orchids (Platanthera chlorantha, Epipactis helleborine, E. neglecta and the mycoheterotrophic Neottia nidus-avis). All investigated species were mycorrhizal generalists (i.e., associated with a large number of fungi simultaneously), but mycorrhizal communities differed significantly between species. Mycorrhizal communities associating with the two Epipactis species consisted of a wide range of fungi belonging to different families, whereas P. chlorantha and N. nidus-avis associated mainly with Ceratobasidiaceae and Sebacinaceae species, respectively. Isotopic signatures differed significantly between both Epipactis species, with E. helleborine showing near autotrophic behavior and E. neglecta showing significant enrichment in both carbon and nitrogen. No significant differences in photosynthesis and stomatal conductance were observed between the two partially mycoheterotrophic orchids, despite significant differences in isotopic signatures. Our results demonstrate that partially mycoheterotrophic orchids of the genus Epipactis formed mycorrhizas with a wide diversity of fungi from different fungal families, but variation in mycorrhizal community composition was not related to isotope signatures and thus transfer of C and N to the plant. We conclude that the observed differences in isotope signatures between E. helleborine and E. neglecta cannot solely be explained by differences in mycorrhizal communities, but most likely reflect a combination of inherent physiological differences and differences in mycorrhizal communities.
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Affiliation(s)
- Hans Jacquemyn
- Department of Biology, Plant Conservation and Population Biology, Department of Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Rein Brys
- Research Institute for Forest and Nature, Geraardsbergen, Belgium
| | - Michael Waud
- Department of Biology, Plant Conservation and Population Biology, Department of Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Alexandra Evans
- Department of Biology, Plant Conservation and Population Biology, Department of Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Tomáš Figura
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Paris, France
- Faculty of Biology, University of Gdańsk, Gdańsk, Poland
| | - Marc-André Selosse
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHE, Paris, France
- Faculty of Biology, University of Gdańsk, Gdańsk, Poland
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19
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Suetsugu K, Matsubayashi J. Evidence for mycorrhizal cheating in Apostasia nipponica, an early-diverging member of the Orchidaceae. THE NEW PHYTOLOGIST 2021; 229:2302-2310. [PMID: 33118174 DOI: 10.1111/nph.17049] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 09/23/2020] [Indexed: 05/12/2023]
Abstract
Most land plants, from liverworts to angiosperms, form mutualistic mycorrhizal symbioses with fungal partners. However, several plants known as mycoheterotrophs exploit fungal partners by reversing the polarity of carbon movement, which usually moves from plant to fungus. We investigated the physiological ecology of a photosynthetic orchid, Apostasia nipponica, which belongs to the first branching group within the Orchidaceae, to improve our understanding of mycoheterotrophic evolution in orchids. The fungal symbionts and nutrition modes of A. nipponica were investigated using molecular barcoding and carbon-13 (13 C) and nitrogen-15 (15 N) measurements, respectively. Community profiling based on a metabarcoding technique revealed that A. nipponica associates with specific Ceratobasidium spp. within ectomycorrhizas-forming clades, whereas isotope analysis revealed that A. nipponica was similar to fully mycoheterotrophic orchids in its 13 C signature and was even more enriched in 15 N than most of the fully mycoheterotrophic orchids that exploit ectomycorrhizal fungi. Our molecular and mass-spectrometric approaches demonstrated, for the first time, that a member of the Apostasioideae, the earliest-diverging lineage of the Orchidaceae, gains carbon through both photosynthesis and fungal cheating (i.e. partial mycoheterotrophy) during the adult stage.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Hyogo, 657-8501, Japan
| | - Jun Matsubayashi
- Department of Integrated Science and Engineering for Sustainable Societies, Faculty of Science and Engineering, Chuo University, Bunkyo-ku, Tokyo, 112-8551, Japan
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20
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Giesemann P, Eichenberg D, Stöckel M, Seifert LF, Gomes SIF, Merckx VSFT, Gebauer G. Dark septate endophytes and arbuscular mycorrhizal fungi (
Paris
‐morphotype) affect the stable isotope composition of ‘classically’ non‐mycorrhizal plants. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13673] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Philipp Giesemann
- Laboratory of Isotope Biogeochemistry Bayreuth Center of Ecology and Environmental Research (BayCEER) University of Bayreuth Bayreuth Germany
| | - David Eichenberg
- Laboratory of Isotope Biogeochemistry Bayreuth Center of Ecology and Environmental Research (BayCEER) University of Bayreuth Bayreuth Germany
| | - Marcus Stöckel
- Laboratory of Isotope Biogeochemistry Bayreuth Center of Ecology and Environmental Research (BayCEER) University of Bayreuth Bayreuth Germany
| | - Lukas F. Seifert
- Laboratory of Isotope Biogeochemistry Bayreuth Center of Ecology and Environmental Research (BayCEER) University of Bayreuth Bayreuth Germany
| | - Sofia I. F. Gomes
- Laboratory of Isotope Biogeochemistry Bayreuth Center of Ecology and Environmental Research (BayCEER) University of Bayreuth Bayreuth Germany
- Naturalis Biodiversity Center Leiden The Netherlands
| | - Vincent S. F. T. Merckx
- Naturalis Biodiversity Center Leiden The Netherlands
- Department of Evolutionary and Population Biology Institute for Biodiversity and Ecosystem Dynamics University of Amsterdam Amsterdam The Netherlands
| | - Gerhard Gebauer
- Laboratory of Isotope Biogeochemistry Bayreuth Center of Ecology and Environmental Research (BayCEER) University of Bayreuth Bayreuth Germany
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21
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Suetsugu K, Matsubayashi J, Tayasu I. Some mycoheterotrophic orchids depend on carbon from dead wood: novel evidence from a radiocarbon approach. THE NEW PHYTOLOGIST 2020; 227:1519-1529. [PMID: 31985062 DOI: 10.1111/nph.16409] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 12/30/2019] [Indexed: 05/25/2023]
Abstract
Mycoheterotrophic plants depend entirely on fungal associations for organic nutrients. While most mycoheterotrophic plants are associated with the mycorrhizal partners of surrounding green plants, some mycoheterotrophs are believed to obtain carbon from decaying litter or dead wood by parasitising saprotrophic fungi, based on culture experiments and 13 C and 15 N isotopic signatures. The carbon age (the time since carbon was fixed from atmospheric CO2 by photosynthesis) can be estimated by measuring the concentration of 14 C arising from the bomb tests of the 1950s and 1960s. Given that mycorrhizal fungi obtain photosynthate from their plant partners, and saprotrophic wood-decaying fungi obtain carbon from older sources, radiocarbon could represent a new and powerful tool to investigate carbon sources of mycoheterotrophic plants. We showed that the Δ14 C values of mycoheterotrophs exploiting ectomycorrhizal fungi were close to 0‰, similar to those of autotrophic plants. By contrast, the Δ14 C values of mycoheterotrophs exploiting saprotrophic fungi ranged from 110.7‰ to 324.8‰, due to the 14 C-enriched bomb carbon from dead wood via saprotrophic fungi. Our study provides evidence supporting that some mycoheterotrophic orchids depend on forest woody debris. Our study also indicates that radiocarbon could be used to predict the trophic strategies of mycoheterotroph-associated fungal symbionts.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Hyogo, 657-8501, Japan
| | - Jun Matsubayashi
- Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, 237-0061, Japan
| | - Ichiro Tayasu
- Research Institute for Humanity and Nature, Kita-ku, Kyoto, 603-8047, Japan
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22
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Shao SC, Wang QX, Beng KC, Zhao DK, Jacquemyn H. Fungi isolated from host protocorms accelerate symbiotic seed germination in an endangered orchid species (Dendrobium chrysotoxum) from southern China. MYCORRHIZA 2020; 30:529-539. [PMID: 32562087 DOI: 10.1007/s00572-020-00964-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/18/2020] [Indexed: 05/03/2023]
Abstract
To ensure long-term survival of epiphytic orchids through active reintroduction, more research on critical life cycle stages such as seed germination and seedling establishment are needed. In this study, we used in vitro germination experiments to investigate the role of mycorrhizal fungi in determining seed germination and growth in the endangered epiphytic orchid species, Dendrobium chrysotoxum. Symbiotic seed germination experiments were conducted for 90 days under different light conditions with fungal strains isolated from protocorms of D. chrysotoxum and three sister species. Molecular analyses showed that five strains belonged to the typical orchid mycorrhizal family Tulasnellaceae, whereas the other two strains belonged to the Sebacinaceae and the genus Coprinellus. Fungal inoculation, light conditions, and their interaction had a significant effect on protocorm formation and seedling development. Three fungal isolates, including two from D. chrysotoxum and one from D. catenatum, significantly stimulated protocorm formation and seedling development under light conditions. However, fungi isolated from host protocorms (GC-14 and GC-15) produced the highest number of seedlings after 50 days (49.5 ± 8.5%, 51.3 ± 9.0%, respectively), while the fungus isolated from D. catenatum protocorms produced the maximum number of seedlings only after 90 days (48.7 ± 16.1%). To conclude, this study has shown that light conditions and the identity of fungi had a strong effect on in vitro seed germination and seedling formation in an epiphytic orchid, with fungi isolated from host protocorms leading to accelerated germination and seedling formation. Therefore, fungal source should be taken into account when using seeds and compatible fungi for seedling propagation and in situ reintroduction.
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Affiliation(s)
- Shi-Cheng Shao
- Gardening and Horticulture Dep artment, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla county, Yunnan, 666 303, People's Republic of China
| | - Qiu-Xia Wang
- College of Agriculture and Life Sciences, Kunming University, Kunming, 650214, People's Republic of China
| | - Kingly C Beng
- Center for Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, 666303, People's Republic of China
- Leibniz Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 301, 12587, Berlin, Germany
| | - Da-Ke Zhao
- School of Life Science, Yunnan University, Kunming, 650504, People's Republic of China.
| | - Hans Jacquemyn
- Department of Biology, Plant Conservation and Population Biology, KU Leuven, Leuven, Belgium.
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23
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Suetsugu K, Matsubayashi J, Ogawa NO, Murata S, Sato R, Tomimatsu H. Isotopic evidence of arbuscular mycorrhizal cheating in a grassland gentian species. Oecologia 2020; 192:929-937. [PMID: 32172377 DOI: 10.1007/s00442-020-04631-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 03/05/2020] [Indexed: 01/25/2023]
Abstract
All orchids and pyroloids are mycoheterotrophic at least in the early stage. Many species are predisposed to mycoheterotrophic nutrition even in the adult stage, due to the initial mycoheterotrophy during germination. Although other green plants, such as gentian species, also produce numerous minute seeds, whose germination may depend on fungal associations to meet C demands, physiological evidence for partial mycoheterotrophy in the adult stage is lacking for most candidate taxa. Here, we compared the natural abundances of 13C and 15N isotopes in the AM-associated gentian species Pterygocalyx volubilis growing in high-light-intensity habitats with those of co-occurring autotrophic C3 and C4 plants and AM fungal spores. We found that P. volubilis was significantly enriched in 13C compared with the surrounding C3 plants, which suggests the transfer of some C from the surrounding autotrophic plants through shared AM networks. In addition, the intermediate δ15N values of P. volubilis, between those of autotrophic plants and AM fungal spores, provide further evidence for partial mycoheterotrophy in P. volubilis. Although it is often considered that light deficiency selects partial mycoheterotrophy, we show that partial mycoheterotrophy in AM-forming plants can evolve even under light-saturated conditions. The fact that there have been relatively few descriptions of partial mycoheterotrophy in AM plants may not necessarily reflect the rarity of such associations. In conclusion, partial mycoheterotrophy in AM plants may be more common than hitherto believed.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan.
| | - Jun Matsubayashi
- Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan
| | - Nanako O Ogawa
- Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan
| | - Satoe Murata
- Faculty of Science, Yamagata University, Yamagata, Japan
| | - Risa Sato
- Faculty of Science, Yamagata University, Yamagata, Japan
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24
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Suetsugu K, Yamato M, Matsubayashi J, Tayasu I. Comparative study of nutritional mode and mycorrhizal fungi in green and albino variants of Goodyera velutina, an orchid mainly utilizing saprotrophic rhizoctonia. Mol Ecol 2019; 28:4290-4299. [PMID: 31448451 DOI: 10.1111/mec.15213] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 07/05/2019] [Accepted: 07/22/2019] [Indexed: 01/30/2023]
Abstract
The majority of chlorophyllous orchids form mycorrhizal associations with so-called rhizoctonia fungi, a phylogenetically heterogeneous assemblage of predominantly saprotrophic fungi in Ceratobasidiaceae, Tulasnellaceae, and Serendipitaceae. It is still a matter of debate whether adult orchids mainly associated with rhizoctonia species are partially mycoheterotrophic. Here, we investigated the nutritional modes of green and albino variants of Goodyera velutina, an orchid species considered to be mainly associated with Ceratobasidium spp., by measuring their 13 C and 15 N abundances, and by molecular barcoding of their mycorrhizal fungi. Molecular analysis revealed that both green and albino variants of G. velutina harbored a similar range of mycobionts, mainly saprotrophic Ceratobasidium spp., Tulasnella spp., and ectomycorrhizal Russula spp. In addition, stable isotope analysis revealed that albino variants were significantly enriched in 13 C but not so greatly in 15 N, suggesting that saprotrophic Ceratobasidium spp. and Tulasnella spp. are their main carbon source. However, in green variants, 13 C levels were depleted and those of 15 N were indistinguishable from the co-occurring autotrophic plants. Therefore, we concluded that the albino G. velutina variants are fully mycoheterotrophic plants whose C derives mainly from saprotrophic rhizoctonia, while the green G. velutina variants are mainly autotrophic plants, at least at our study site, in spite of their additional associations with ectomycorrhizal fungi. This is the first report demonstrating that adult nonphotosynthetic albino variants can obtain their nutrition mainly from nonectomycorrhizal rhizoctonia.
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Affiliation(s)
- Kenji Suetsugu
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | | | - Jun Matsubayashi
- Department of Biogeochemistry, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan
| | - Ichiro Tayasu
- Research Institute for Humanity and Nature, Kyoto, Japan
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25
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Light limitation and partial mycoheterotrophy in rhizoctonia-associated orchids. Oecologia 2019; 189:375-383. [PMID: 30673856 DOI: 10.1007/s00442-019-04340-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 01/12/2019] [Indexed: 12/20/2022]
Abstract
Partially mycoheterotrophic (PMH) plants obtain organic molecules from their mycorrhizal fungi in addition to carbon (C) fixed by photosynthesis. Some PMH orchids associated with ectomycorrhizal fungi have been shown to flexibly adjust the proportion of organic molecules obtained from fungi according to the habitat's light level. We hypothesise that Neottia ovata and Ophrys insectifera, two orchids associated with saprotrophic rhizoctonia fungi, are also able to increase uptake of organic molecules from fungi as irradiance levels decrease. We continuously measured light availability for individuals of N. ovata and O. insectifera at a grassland and a forest during orchid flowering and fruiting. We repeatedly sampled leaves of N. ovata, O. insectifera and autotrophic reference species for stable isotope natural abundances (δ13C, δ15N, δ2H, δ18O) and C and N concentrations. We found significant 13C enrichment in both orchids relative to autotrophic references at the forest but not the grassland, and significant 2H enrichment at both sites. The 13C enrichment in O. insectifera was linearly correlated with the habitat's irradiance levels. We conclude that both species can be considered as PMH and at least in O. insectifera, the degree of partial mycoheterotrophy can be fine-tuned according to light availability. However, exploitation of mycorrhizal fungi appears less flexible in saprotroph-associated orchids than in orchids associated with ectomycorrhizal fungi.
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26
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Cormier MA, Werner RA, Leuenberger MC, Kahmen A. 2H-enrichment of cellulose and n-alkanes in heterotrophic plants. Oecologia 2019; 189:365-373. [DOI: 10.1007/s00442-019-04338-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 01/11/2019] [Indexed: 11/30/2022]
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