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Zhao DK, Mou ZM, Ruan YL. Orchids acquire fungal carbon for seed germination: pathways and players. TRENDS IN PLANT SCIENCE 2024; 29:733-741. [PMID: 38423891 DOI: 10.1016/j.tplants.2024.02.001] [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: 08/03/2023] [Revised: 01/31/2024] [Accepted: 02/05/2024] [Indexed: 03/02/2024]
Abstract
To germinate in nature, orchid seeds strictly rely on seed germination-promoting orchid mycorrhizal fungi (sgOMFs) for provision of carbon nutrients. The underlying delivery pathway, however, remains elusive. We develop here a plausible model for sugar transport from sgOMFs to orchid embryonic cells to fuel germination. Orchids exploit sgOMFs to induce the formation of pelotons, elaborate intracellular hyphal coils in orchid embryos. The colonized orchid cells then obtain carbon nutrients by uptake from living hyphae and peloton lysis, primarily as glucose derived from fungal trehalose hydrolyzed by orchid-specific trehalases. The uptake of massive fungally derived glucose is likely to be mediated by two classes of membrane proteins, namely, sugars will eventually be exported transporters (SWEETs) and H+-hexose symporters. The proposed model serves as a launch pad for further research to better understand and improve orchid seed germination and conservation.
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Affiliation(s)
- Da-Ke Zhao
- School of Ecology and Environmental Science, Yunnan University, Kunming 650504, China
| | - Zong-Min Mou
- School of Ecology and Environmental Science, Yunnan University, Kunming 650504, China.
| | - Yong-Ling Ruan
- State Key Laboratory of Crop Stress Biology in Arid Areas and College of Horticulture, Northwest A&F University, Xianyang 712100, China; Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia.
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2
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Wong S, Kaur J, Kumar P, Karremans AP, Sharma J. Distinct orchid mycorrhizal fungal communities among co-occurring Vanilla species in Costa Rica: root substrate and population-based segregation. MYCORRHIZA 2024; 34:229-250. [PMID: 38664239 DOI: 10.1007/s00572-024-01147-7] [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: 11/30/2023] [Accepted: 04/15/2024] [Indexed: 06/12/2024]
Abstract
Despite being the second largest family of flowering plants, orchids represent community structure variation in plant-microbial associations, contributes to niche partitioning in metacommunity assemblages. Yet, mycorrhizal communities and interactions remain unknown for orchids that are highly specialized or even obligated in their associations with their mycorrhizal partners. In this study, we sought to compare orchid mycorrhizal fungal (OMF) communities of three co-occurring hemiepiphytic Vanilla species (V. hartii, V. pompona, and V. trigonocarpa) in tropical forests of Costa Rica by addressing the identity of their OMF communities across species, root types, and populations, using high-throughput sequencing. Sequencing the nuclear ribosomal internal transcribed spacer (nrITS) yielded 299 fungal Operational Taxonomic Units (OTUs) from 193 root samples. We showed distinct segregation in the putative OMF (pOMF) communities of the three coexisting Vanilla hosts. We also found that mycorrhizal communities associated with the rare V. hartii varied among populations. Furthermore, we identified Tulasnellaceae and Ceratobasidiaceae as dominant pOMF families in terrestrial roots of the three Vanilla species. In contrast, the epiphytic roots were mainly dominated by OTUs belonging to the Atractiellales and Serendipitaceae. Furthermore, the pOMF communities differed significantly across populations of the widespread V. trigonocarpa and showed patterns of distance decay in similarity. This is the first report of different pOMF communities detected in roots of wild co-occurring Vanilla species using high-throughput sequencing, which provides evidence that three coexisting Vanilla species and their root types exhibited pOMF niche partitioning, and that the rare and widespread Vanilla hosts displayed diverse mycorrhizal preferences.
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Affiliation(s)
- Shan Wong
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, 79409, USA.
| | - Jaspreet Kaur
- Department of Biology, University of Wisconsin-La Crosse, 1725 State Street, La Crosse, WI, 54601, USA
| | - Pankaj Kumar
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, 79409, USA
| | - Adam P Karremans
- Lankester Botanical Garden, University of Costa Rica, P.O. Box 302-7050, Cartago, Costa Rica
| | - Jyotsna Sharma
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, 79409, USA
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Tian F, Wang JC, Bai XX, Yang YB, Huang L, Liao XF. Symbiotic seed germination and seedling growth of mycorrhizal fungi in Paphiopedilum hirsutissimun (Lindl.Ex Hook.) Stein from China. PLANT SIGNALING & BEHAVIOR 2023; 18:2293405. [PMID: 38104263 PMCID: PMC10730140 DOI: 10.1080/15592324.2023.2293405] [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: 07/03/2023] [Accepted: 08/11/2023] [Indexed: 12/19/2023]
Abstract
Similar to other orchid species, Paphiopedilum hirsutissimum (Lindl.ex Hook.) Stein, relies on nutrients provided by mycorrhizal fungus for seed germination and seedling development in the wild owing to a lack of endosperm in its seeds. Therefore, obtaining suitable and specialized fungi to enhance seed germination, seedling formation, and further development is considered a powerful tool for orchid seedling propagation, reintroduction, and species conservation. In this study, we investigated the diversity, abundance, and frequency of endophytic fungal strains in the root organs of P. hirsutissimum. One family and five genera of the fungi were isolated and identified through rDNA-ITS sequencing. The ability of isolated fungi to germinate in vitro from the seeds of this species was evaluated, and the development of P. hirsutissimum protocorm has been described. The findings showed that the treatments inoculated with endophytic fungal DYXY033 may successfully support the advanced developmental stage of seedlings up to stage 5. In addition, scanning electron microscopy (SEM) revealed that the mycelium of this strain began to invade from either end of the seeds up to the embryo, extending rapidly from the inside to the outside. Its lengthening resulted in the bursting of the seed coat to form protocorms, which developed into seedlings. The results showed that DYXY033 has a high degree of mycobiont specificity under in vitro symbiotic seed germination conditions and is a representative mycorrhizal fungus with ecological value for the species. In summary, this strain may particularly be significant for the protection of P. hirsutissimum species that are endangered in China. In the long run, it may also contribute to global efforts in reintroducing orchid species and in realizing in situ restorations of threatened orchid populations.
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Affiliation(s)
- Fan Tian
- Guizhou Academy of Forestry, Guiyang, Guizhou, China
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Guiyang, Guizhou, China
| | - Jun-Cai Wang
- Advanced Technology and Materials Research Institute, Guizhou Academy of Sciences, Guiyang, Guizhou, China
| | - Xin-Xiang Bai
- College of Forestry, Guizhou University, Guiyang, Guizhou, China
| | - Yan-Bing Yang
- Guizhou Academy of Forestry, Guiyang, Guizhou, China
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Guiyang, Guizhou, China
| | - Lang Huang
- Guizhou Academy of Forestry, Guiyang, Guizhou, China
- Key Laboratory of National Forestry and Grassland Administration on Biodiversity Conservation in Karst Mountainous Areas of Southwestern China, Guiyang, Guizhou, China
| | - Xiao-Feng Liao
- Advanced Technology and Materials Research Institute, Guizhou Academy of Sciences, Guiyang, Guizhou, China
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Calevo J, Duffy KJ. Interactions among mycorrhizal fungi enhance the early development of a Mediterranean orchid. MYCORRHIZA 2023; 33:229-240. [PMID: 37436449 PMCID: PMC10442268 DOI: 10.1007/s00572-023-01118-4] [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: 01/23/2023] [Accepted: 06/20/2023] [Indexed: 07/13/2023]
Abstract
Orchids depend on mycorrhizal fungi to germinate from seed. While multiple orchid mycorrhizal (OrM) taxa are often found associated with adult orchids, the relative contribution of particular OrM taxa to germination and early orchid development is poorly understood. We isolated 28 OrM fungi associated with the Mediterranean orchid Anacamptis papilionacea and tested the efficiency of five isolates on germination and early development, four belonging to the Tulasnella calospora species complex and one belonging to Ceratobasidium. Co-cultures of varying two-way and three-way combinations of OrM isolates were used in vitro to compare the simultaneous effect on seed germination rate with monocultures. We then tested whether, when given initial priority over other fungi, particular OrM taxa were more effective during the early stages of development. Seedlings germinated with different isolates were transferred to a growth chamber, and either the same or different isolate was added 45 days later. After 3 months, the number of roots, length of the longest root, and tuber area were measured. All OrM fungi resulted in seed germination; however, lower germination rates were associated with the Ceratobasidium isolate compared to the tulasnelloid isolates. There was significant decreased germination in co-culture experiments when the Ceratobasidium isolate was added. Despite being associated with reduced germination rates, the addition of the Ceratobasidium isolate to the seedlings germinated with tulasnelloid strains resulted in significant increased tuber size. Although A. papilionacea associates with many OrM taxa, these results show that OrM fungi may play different roles during orchid germination and early development. Even when given initial priority, other fungi may colonize developing orchids and interact to influence early orchid development.
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Affiliation(s)
- Jacopo Calevo
- Department of Biology, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cinthia, 80126, Naples, Italy.
| | - Karl J Duffy
- Department of Biology, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Via Cinthia, 80126, Naples, Italy.
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Arifin AR, Phillips RD, Linde CC. Strong phylogenetic congruence between Tulasnella fungi and their associated Drakaeinae orchids. J Evol Biol 2023; 36:221-237. [PMID: 36309962 PMCID: PMC10091943 DOI: 10.1111/jeb.14107] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 01/11/2023]
Abstract
The study of congruency between phylogenies of interacting species can provide a powerful approach for understanding the evolutionary history of symbiotic associations. Orchid mycorrhizal fungi can survive independently of orchids making cospeciation unlikely, leading us to predict that any congruence would arise from host-switches to closely related fungal species. The Australasian orchid subtribe Drakaeinae is an iconic group of sexually deceptive orchids that consists of approximately 66 species. In this study, we investigated the evolutionary relationships between representatives of all six Drakaeinae orchid genera (39 species) and their mycorrhizal fungi. We used an exome capture dataset to generate the first well-resolved phylogeny of the Drakaeinae genera. A total of 10 closely related Tulasnella Operational Taxonomic Units (OTUs) and previously described species were associated with the Drakaeinae orchids. Three of them were shared among orchid genera, with each genus associating with 1-6 Tulasnella lineages. Cophylogenetic analyses show Drakaeinae orchids and their Tulasnella associates exhibit significant congruence (p < 0.001) in the topology of their phylogenetic trees. An event-based method also revealed significant congruence in Drakaeinae-Tulasnella relationships, with duplications (35), losses (25), and failure to diverge (9) the most frequent events, with minimal evidence for cospeciation (1) and host-switches (2). The high number of duplications suggests that the orchids speciate independently from the fungi, and the fungal species association of the ancestral orchid species is typically maintained in the daughter species. For the Drakaeinae-Tulasnella interaction, a pattern of phylogenetic niche conservatism rather than coevolution likely explains the observed phylogenetic congruency in orchid and fungal phylogenies. Given that many orchid genera are characterized by sharing of fungal species between closely related orchid species, we predict that these findings may apply to a wide range of orchid lineages.
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Affiliation(s)
- Arild R Arifin
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia.,Department of Plant Pathology, Washington State University Tree Fruit Research and Extension Center, Wenatchee, Washington, USA
| | - Ryan D Phillips
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia.,Department of Ecology, Environment & Evolution, La Trobe University, Bundoora, Victoria, Australia.,Department of Biodiversity, Conservation and Attractions, Kings Park Science, Perth, Western Australia, Australia.,Royal Botanic Gardens Victoria, Victoria, Australia
| | - Celeste C Linde
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
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Addition of fungal inoculum increases seed germination and protocorm formation in a terrestrial orchid. Glob Ecol Conserv 2022. [DOI: 10.1016/j.gecco.2022.e02235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Ceratobasidium orchid mycorrhizal fungi reveal intraspecific variation and interaction with different nutrient media in symbiotic germination of Prasophyllum (Orchidaceae). Symbiosis 2022. [DOI: 10.1007/s13199-022-00874-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
AbstractUnderstanding how nutrient requirements of orchid mycorrhizal fungi (OMF) affect symbiotic germination is essential for the ex situ conservation of threatened orchids and their mycorrhizal symbioses. Yet the influence of isolate-level variation in OMF nutrient preferences on orchid germination is unknown. We tested germination of Prasophyllum frenchii (Orchidaceae) on 15 different media of varying carbon and macronutrient compositions with three Ceratobasidium isolates of the same operational taxonomic unit (OTU) as determined with internal transcribed spacer locus sequencing. There was a significant interaction between media and fungal isolate on percentage germination, with each isolate recording its highest percentage germination on different nutrient media (Isolate 9.3: 5.2 ± 1.4% on MOM–S; Isolate 8.2: 5.4 ± 1.1% on MOM + S; Isolate 4.3: 2.2 ± 0.5% on 1.25 g/L wheat bran agar). Across all isolates, germination (percentage germination > 0) occurred more frequently on wheat bran agar media (39.7% of plates) than on oatmeal agar media (6.0% of plates). There was also an effect of media type on aerial hyphal growth behaviour of the OMF isolate. All isolates supported growth through to adult flowering plants. We demonstrated that symbiotic germination of Prasophyllum is affected by media composition. Further, percentage germination and aerial hyphal growth behaviour differed significantly among OMF isolates of the same OTU. This illustrates that a diversity of functionally significant fungal strains occurs within a single OTU, a previously unknown aspect of OMF research with important ecological and conservation implications.
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Herrera H, Sanhueza T, da Silva Valadares RB, Matus F, Pereira G, Atala C, Mora MDLL, Arriagada C. Diversity of Root-Associated Fungi of the Terrestrial Orchids Gavilea lutea and Chloraea collicensis in a Temperate Forest Soil of South-Central Chile. J Fungi (Basel) 2022; 8:jof8080794. [PMID: 36012784 PMCID: PMC9409917 DOI: 10.3390/jof8080794] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/18/2022] [Accepted: 07/23/2022] [Indexed: 11/16/2022] Open
Abstract
The diversity of orchid mycorrhizal fungi (OMF) and other beneficial root-associated fungi in temperate forests has scarcely been examined. This study aimed to analyze the diversity of mycorrhizal and rhizosphere-associated fungal communities in the terrestrial orchids Gavilea lutea and Chloraea collicensis growing in high-orchid-population-density areas in the piedmont of the Andes Cordillera with native forest (Nothofagus-Araucaria) and Coastal Cordillera with an exotic plantation (Pinus-Eucalyptus) in south-central Chile. We focused on rhizosphere-inhabiting and peloton-associated OMF in a native forest (Andes Cordillera) and a mixed forest (Coastal Cordillera). The native terrestrial orchids G. lutea and C. collicensis were localized, mycorrhizal root segments were taken to isolate peloton-associated OMF, and rhizosphere soil was taken to perform the metabarcoding approach. The results revealed that Basidiomycota and Ascomycota were the main rhizosphere-inhabiting fungal phyla, showing significant differences in the composition of fungal communities in both sites. Sebacina was the most-abundant OMF genera in the rhizosphere of G. lutea growing in the native forest soil. In contrast, Thanatephorus was the most abundant mycorrhizal taxa growing in the rhizosphere of orchids from the Coastal Cordillera. Besides, other OMF genera such as Inocybe, Tomentella, and Mycena were detected. The diversity of OMF in pelotons differed, being mainly related to Ceratobasidium sp. and Tulasnella sp. These results provide evidence of differences in OMF from pelotons and the rhizosphere soil in G. lutea growing in the Andes Cordillera and a selection of microbial communities in the rhizosphere of C. collicensis in the Coastal Cordillera. This raises questions about the efficiency of propagation strategies based only on mycorrhizal fungi obtained by culture-dependent methods, especially in orchids that depend on non-culturable taxa for seed germination and plantlet development.
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Affiliation(s)
- Héctor Herrera
- Laboratorio de Biorremediación, Departamento de Ciencias Forestales, Facultad de Ciencias Agropecuarias y Forestales, Universidad de La Frontera, Temuco 4780000, Chile;
- Correspondence: (H.H.); (C.A.)
| | - Tedy Sanhueza
- Laboratorio de Biorremediación, Departamento de Ciencias Forestales, Facultad de Ciencias Agropecuarias y Forestales, Universidad de La Frontera, Temuco 4780000, Chile;
- Programa de Magister en Manejo de Recursos Naturales, Universidad de La Frontera, Casilla 54-D, Francisco Salazar 01145, Temuco 4780000, Chile
| | | | - Francisco Matus
- Laboratory of Conservation and Dynamics of Volcanic Soils, Department of Chemical Sciences and Natural Resources, Universidad de La Frontera, Temuco 4780000, Chile;
- Network for Extreme Environmental Research (NEXER), Universidad de La Frontera, Temuco 4780000, Chile
| | - Guillermo Pereira
- Departamento de Ciencias y Tecnología Vegetal, Laboratorio Biotecnología de Hongos, Universidad de Concepción, Los Angeles 4440000, Chile;
| | - Cristian Atala
- Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaiso 2340000, Chile;
| | - María de la Luz Mora
- Scientific and Technological Bioresource Nucleus, Universidad de La Frontera, Temuco 4780000, Chile;
| | - Cesar Arriagada
- Laboratorio de Biorremediación, Departamento de Ciencias Forestales, Facultad de Ciencias Agropecuarias y Forestales, Universidad de La Frontera, Temuco 4780000, Chile;
- Correspondence: (H.H.); (C.A.)
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Arifin AR, Phillips RD, Weinstein AM, Linde CC. Cryptostylis species (Orchidaceae) from a broad geographic and habitat range associate with a phylogenetically narrow lineage of Tulasnellaceae fungi. Fungal Biol 2022; 126:534-546. [DOI: 10.1016/j.funbio.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/14/2022] [Accepted: 06/20/2022] [Indexed: 11/04/2022]
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Davis B, Lim WH, Lambers H, Dixon KW, Read DJ. Inorganic phosphorus nutrition in green-leaved terrestrial orchid seedlings. ANNALS OF BOTANY 2022; 129:669-678. [PMID: 35247265 PMCID: PMC9113155 DOI: 10.1093/aob/mcac030] [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: 12/09/2021] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND AIMS Many terrestrial orchids have an obligate dependence on their mycorrhizal associations for nutrient acquisition, particularly during germination and early seedling growth. Though important in plant growth and development, phosphorus (P) nutrition studies in mixotrophic orchids have been limited to only a few orchid species and their fungal symbionts. For the first time, we demonstrate the role of a range of fungi in the acquisition and transport of inorganic P to four phylogenetically distinct green-leaved terrestrial orchid species (Diuris magnifica, Disa bracteata, Pterostylis sanguinea and Microtis media subsp. media) that naturally grow in P-impoverished soils. METHODS Mycorrhizal P uptake and transfer to orchids was determined and visualized using agar microcosms with a diffusion barrier between P source (33P orthophosphate) and orchid seedlings, allowing extramatrical hyphae to reach the source. KEY RESULTS Extramatrical hyphae of the studied orchid species were effective in capturing and transporting inorganic P into the plant. Following 7 d of exposure, between 0.5 % (D. bracteata) and 47 % (D. magnifica) of the P supplied was transported to the plants (at rates between 0.001 and 0.097 fmol h-1). This experimental approach was capable of distinguishing species based on their P-foraging efficiency, and highlighted the role that fungi play in P nutrition during early seedling development. CONCLUSIONS Our study shows that orchids occurring naturally on P-impoverished soils can obtain significant amounts of inorganic P from their mycorrhizal partners, and significantly more uptake of P supplied than previously shown in other green-leaved orchids. These results provide support for differences in mycorrhiza-mediated P acquisition between orchid species and fungal symbionts in green-leaved orchids at the seedling stage. The plant-fungus combinations of this study also provide evidence for plant-mediated niche differentiation occurring, with ecological implications in P-limited systems.
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Affiliation(s)
- Belinda Davis
- Kings Park Science, Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, 2 Kattidj Close, Kings Park, WA, Australia
- School of Biological Sciences, The University of Western Australia, Crawley, Perth, WA, Australia
| | - Wei-Han Lim
- Kings Park Science, Biodiversity and Conservation Science, Department of Biodiversity, Conservation and Attractions, 2 Kattidj Close, Kings Park, WA, Australia
- School of Biological Sciences, The University of Western Australia, Crawley, Perth, WA, Australia
| | - Hans Lambers
- School of Biological Sciences, The University of Western Australia, Crawley, Perth, WA, Australia
- Environment and Agriculture, Curtin University, Bentley, 6102, Western Australia
| | - Kingsley W Dixon
- School of Biological Sciences, The University of Western Australia, Crawley, Perth, WA, Australia
- Environment and Agriculture, Curtin University, Bentley, 6102, Western Australia
| | - David J Read
- School of Biological Sciences, The University of Western Australia, Crawley, Perth, WA, Australia
- Department of Animal and Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield, UK
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Mycorrhizal Compatibility and Germination-Promoting Activity of Tulasnella Species in Two Species of Orchid (Cymbidium mannii and Epidendrum radicans). HORTICULTURAE 2021. [DOI: 10.3390/horticulturae7110472] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In nature, Orchidaceae seeds establish a relationship with orchid mycorrhizal fungi to obtain essential nutrients for germination. The orchids, Cymbidium mannii and Epidendrum radicans, have significant ornamental and economic value. We isolated and cultured mycorrhizal fungi from C. mannii, E. radicans, and C. goeringii roots. Three strains of fungi, Tulasnella calospora (Tca), T. asymmetrica (Tas), and T. bifrons (Tbi), were identified using ITS-rDNA sequencing. Their mycorrhizal compatibility, germination-promoting effects, and symbiosis with the seeds of C. mannii and E. radicans were studied in vitro using various concentrations of oatmeal agar (OA) medium. Tca exhibited significant seed-germination-promoting effects on C. mannii (92.1%) and E. radicans (84.7%) on 2.0 and 4.0 g/L OA, respectively. For Tbi and Tas, the highest germination percentages were observed on 4.0 g/L OA in E. radicans (73.60% and 76.49%, respectively). Seed germination in C. mannii was enhanced by high oatmeal concentrations (8.0 and 12.0 g/L) during symbiosis with Tas, whereas Tbi had no effect regardless of OA concentration. Tca exhibited high compatibility with C. mannii and E. radicans, and the oatmeal concentration of the medium affected this compatibility. The findings of this study will aid in the propagation of endangered orchid species for conservation and commercial purposes using mycorrhizal technology.
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Freestone MW, Swarts ND, Reiter N, Tomlinson S, Sussmilch FC, Wright MM, Holmes GD, Phillips RD, Linde CC. Continental-scale distribution and diversity of Ceratobasidium orchid mycorrhizal fungi in Australia. ANNALS OF BOTANY 2021; 128:329-343. [PMID: 34077492 PMCID: PMC8389474 DOI: 10.1093/aob/mcab067] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 05/29/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND AIMS Mycorrhizal fungi are a critical component of the ecological niche of most plants and can potentially constrain their geographical range. Unlike other types of mycorrhizal fungi, the distributions of orchid mycorrhizal fungi (OMF) at large spatial scales are not well understood. Here, we investigate the distribution and diversity of Ceratobasidium OMF in orchids and soils across the Australian continent. METHODS We sampled 217 Ceratobasidium isolates from 111 orchid species across southern Australia and combined these with 311 Ceratobasidium sequences from GenBank. To estimate the taxonomic diversity of Ceratobasidium associating with orchids, phylogenetic analysis of the ITS sequence locus was undertaken. Sequence data from the continent-wide Australian Microbiome Initiative were used to determine the geographical range of operational taxonomic units (OTUs) detected in orchids, with the distribution and climatic correlates of the two most frequently detected OTUs modelled using MaxEnt. KEY RESULTS We identified 23 Ceratobasidium OTUs associating with Australian orchids, primarily from the orchid genera Pterostylis, Prasophyllum, Rhizanthella and Sarcochilus. OTUs isolated from orchids were closely related to, but distinct from, known pathogenic fungi. Data from soils and orchids revealed that ten of these OTUs occur on both east and west sides of the continent, while 13 OTUs were recorded at three locations or fewer. MaxEnt models suggested that the distributions of two widespread OTUs are correlated with temperature and soil moisture of the wettest quarter and far exceeded the distributions of their host orchid species. CONCLUSIONS Ceratobasidium OMF with cross-continental distributions are common in Australian soils and frequently have geographical ranges that exceed that of their host orchid species, suggesting these fungi are not limiting the distributions of their host orchids at large spatial scales. Most OTUs were distributed within southern Australia, although several OTUs had distributions extending into central and northern parts of the continent, illustrating their tolerance of an extraordinarily wide range of environmental conditions.
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Affiliation(s)
- Marc W Freestone
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
- Royal Botanic Gardens Victoria, Cranbourne, VIC 3977, Australia
- Biodiversity and Conservation Division, Department of Agriculture, Water and Environment, Canberra, ACT 2600, Australia
| | - Nigel D Swarts
- Tasmanian Institute of Agriculture, The University of Tasmania, Sandy Bay, TAS 7005, Australia
- Royal Tasmanian Botanical Gardens, Hobart, TAS 7000, Australia
| | - Noushka Reiter
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
- Royal Botanic Gardens Victoria, Cranbourne, VIC 3977, Australia
| | - Sean Tomlinson
- Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, West Perth, WA 6005, Australia
| | - Frances C Sussmilch
- Tasmanian Institute of Agriculture, The University of Tasmania, Sandy Bay, TAS 7005, Australia
| | - Magali M Wright
- Royal Tasmanian Botanical Gardens, Hobart, TAS 7000, Australia
| | - Gareth D Holmes
- Royal Botanic Gardens Victoria, Cranbourne, VIC 3977, Australia
| | - Ryan D Phillips
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
- Royal Botanic Gardens Victoria, Cranbourne, VIC 3977, Australia
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, West Perth, WA 6005, Australia
- Department of Ecology, Environment and Evolution, LaTrobe University, Bundoora, VIC 3086, Australia
| | - Celeste C Linde
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2600, Australia
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13
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Oktalira FT, May TW, Dearnaley JDW, Linde CC. Seven new Serendipita species associated with Australian terrestrial orchids. Mycologia 2021; 113:968-987. [PMID: 34338610 DOI: 10.1080/00275514.2021.1919848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Serendipita is one of the main fungal genera that form mutualistic associations with species of orchids (Orchidaceae). Here, seven new Serendipita species associated with various Australian orchid genera are described. These Serendipita species were originally characterized by multilocus DNA sequence species delimitation analyses (three mtDNA and four nuclear genes) and confirmed as distinct with addition of further isolates and reanalysis of nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS) and nuc 28S rDNA (28S). Culture morphology and microscopic features are presented for each species, three of which are binucleate and four multinucleate. For the ITS region, the seven species have within-species sequence divergence between 1.07% and 4.31%, and all but one of the species pairs is separated by interspecific divergence of at least 4.35%. The newly described Serendipita species, S. australiana, S. communis, S. occidentalis, S. rarihospitum, S. secunda, S. talbotii, and S. warcupii, are shown to be separate species from S. vermifera on the basis of comparison against a sequence from the type. Isolates originally identified by Warcup as Sebacina "vermifera" from Caladenia orchids are revised and shown to belong to three of the species newly described here. Some non-Caladenia isolates identified by Warcup as S. "vermifera" are also shown to be non-conspecific with the type of S. vermifera. On the basis of ITS sequences, 346 isolates from 26 other studies, previously identified under provisional designations, are accommodated under the novel species. The species of Serendipta described here associate with the Australian orchid genera Caladenia, Cyanicula, Elythranthera, Ericksonella, Eriochilus, Glossodia, and Pheladenia. Most of the novel Serendipita species occur widely across Australia, often with widely distributed hosts, but one species, Serendipita rarihospitum, associates with narrowly distributed orchid species.
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Affiliation(s)
- Fitria T Oktalira
- Ecology and Evolution, Research School of Biology, College of Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Tom W May
- Royal Botanic Gardens Victoria, Birdwood Avenue, Melbourne, VIC 3004, Australia
| | - John D W Dearnaley
- Centre for Crop Health, The University of Southern Queensland, Toowoomba, Queensland 4350, Australia
| | - Celeste C Linde
- Ecology and Evolution, Research School of Biology, College of Science, The Australian National University, Canberra, ACT 2601, Australia
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14
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Zhao DK, Selosse MA, Wu L, Luo Y, Shao SC, Ruan YL. Orchid Reintroduction Based on Seed Germination-Promoting Mycorrhizal Fungi Derived From Protocorms or Seedlings. FRONTIERS IN PLANT SCIENCE 2021; 12:701152. [PMID: 34276753 PMCID: PMC8278863 DOI: 10.3389/fpls.2021.701152] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/04/2021] [Indexed: 06/13/2023]
Abstract
Orchids are among the most endangered in the plant kingdom. Lack of endosperm in their seeds renders orchids to depend on nutrients provided by orchid mycorrhizal fungi (OMF) for seed germination and seedling formation in the wild. OMF that parasitize in germination seeds is an essential element for orchid seedling formation, which can also help orchid reintroduction. Considering the limitations of the previous orchid reintroduction technology based on seed germination-promoting OMF (sgOMF) sourced from orchid roots, an innovative approach is proposed here in which orchid seeds are directly co-sown with sgOMF carrying ecological specificity from protocorms/seedlings. Based on this principle, an integrative and practical procedure concerning related ecological factors is further raised for re-constructing long-term and self-sustained orchid populations. We believe that this new approach will benefit the reintroduction of endangered orchids in nature.
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Affiliation(s)
- Da-Ke Zhao
- Biocontrol Engineering Research Center of Plant Disease and Pest, Biocontrol Engineering Research Center of Crop Disease and Pest, School of Ecology and Environmental Science, Yunnan University, Kunming, China
| | - Marc-André Selosse
- Département Systématique et Evolution, UMR 7205 ISYEB, Muséum National d'Histoire Naturelle, Paris, France
- Faculty of Biology, University of Gdansk, Gdansk, Poland
| | - Limin Wu
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
| | - Yan Luo
- Gardening and Horticulture Department, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Shi-Cheng Shao
- Gardening and Horticulture Department, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Yong-Ling Ruan
- Australia-China Research Centre for Crop Improvement, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW, Australia
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15
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Kaur J, Sharma J. Orchid Root Associated Bacteria: Linchpins or Accessories? FRONTIERS IN PLANT SCIENCE 2021; 12:661966. [PMID: 34249034 PMCID: PMC8264303 DOI: 10.3389/fpls.2021.661966] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 05/19/2021] [Indexed: 05/28/2023]
Abstract
Besides the plant-fungus symbiosis in arbuscular mycorrhizal (AM) and ectomycorrhizal (EM) plants, many endorhizal and rhizosphere bacteria (Root Associated Bacteria, or RAB) also enhance plant fitness, diversity, and coexistence among plants via bi- or tripartite interactions with plant hosts and mycorrhizal fungi. Assuming that bacterial associations are just as important for the obligate mycorrhizal plant family Orchidaceae, surprisingly little is known about the RAB associated with orchids. Herein, we first present the current, underwhelming state of RAB research including their interactions with fungi and the influence of holobionts on plant fitness. We then delineate the need for novel investigations specifically in orchid RAB ecology, and sketch out questions and hypotheses which, when addressed, will advance plant-microbial ecology. We specifically discuss the potential effects of beneficial RAB on orchids as: (1) Plant Growth Promoting Rhizobacteria (PGPR), (2) Mycorrhization Helper Bacteria (MHB), and (3) constituents of an orchid holobiont. We further posit that a hologenomic view should be considered as a framework for addressing co-evolution of the plant host, their obligate Orchid Mycorrhizal Fungi (OMF), and orchid RAB. We conclude by discussing implications of the suggested research for conservation of orchids, their microbial partners, and their collective habitats.
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Affiliation(s)
- Jaspreet Kaur
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, United States
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16
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Stephan P, Bramon Mora B, Alexander JM. Positive species interactions shape species' range limits. OIKOS 2021. [DOI: 10.1111/oik.08146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Pauline Stephan
- Dept of Environmental Systems Science, ETH Zürich Zürich Switzerland
| | | | - Jake M. Alexander
- Dept of Environmental Systems Science, ETH Zürich Zürich Switzerland
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17
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Li T, Wu S, Yang W, Selosse MA, Gao J. How Mycorrhizal Associations Influence Orchid Distribution and Population Dynamics. FRONTIERS IN PLANT SCIENCE 2021; 12:647114. [PMID: 34025695 PMCID: PMC8138319 DOI: 10.3389/fpls.2021.647114] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 04/13/2021] [Indexed: 05/04/2023]
Abstract
Orchid distribution and population dynamics are influenced by a variety of ecological factors and the formation of holobionts, which play key roles in colonization and ecological community construction. Seed germination, seedling establishment, reproduction, and survival of orchid species are strongly dependent on orchid mycorrhizal fungi (OMF), with mycorrhizal cheating increasingly observed in photosynthetic orchids. Therefore, changes in the composition and abundance of OMF can have profound effects on orchid distribution and fitness. Network analysis is an important tool for the study of interactions between plants, microbes, and the environment, because of the insights that it can provide into the interactions and coexistence patterns among species. Here, we provide a comprehensive overview, systematically describing the current research status of the effects of OMF on orchid distribution and dynamics, phylogenetic signals in orchid-OMF interactions, and OMF networks. We argue that orchid-OMF associations exhibit complementary and specific effects that are highly adapted to their environment. Such specificity of associations may affect the niche breadth of orchid species and act as a stabilizing force in plant-microbe coevolution. We postulate that network analysis is required to elucidate the functions of fungal partners beyond their effects on germination and growth. Such studies may lend insight into the microbial ecology of orchids and provide a scientific basis for the protection of orchids under natural conditions in an efficient and cost-effective manner.
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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
| | - 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
| | - 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
| | - 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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18
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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: 22] [Impact Index Per Article: 7.3] [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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19
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Štípková Z, Tsiftsis S, Kindlmann P. Distribution of Orchids with Different Rooting Systems in the Czech Republic. PLANTS (BASEL, SWITZERLAND) 2021; 10:632. [PMID: 33810576 PMCID: PMC8067186 DOI: 10.3390/plants10040632] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 11/23/2022]
Abstract
Understanding diversity patterns along altitudinal gradients and the effect of global change on abundance, distribution patterns and species survival are of the most discussed topics in biodiversity research. Here, we determined the associations of orchid species richness and the degree of their specialization to specific environmental conditions (expressed by species specialization index) with altitude in six floristic areas in the Czech Republic. We distinguished three basic trends in these relationships: linear, parabolic and cubic. We then determined whether these trends differ between three orchid groups classified by their rooting systems: rhizomatous, intermediate and tuberous. We used distributional data on 69 species and subspecies of terrestrial orchids recorded in the Czech Republic and interpolated them at 100-m intervals along an altitudinal gradient in each floristic area. The trends in both species richness and mean species specialization index differed between the six floristic areas within each of the three orchid groups studied. These patterns are probably strongly influenced by the orography of the country and the distribution of different habitats in the six floristic areas in the Czech Republic. We also found that the most widely distributed orchid group in the Czech Republic are the rhizomatous orchids, followed by intermediate and tuberous ones.
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Affiliation(s)
- Zuzana Štípková
- Global Change Research Institute, Academy of Sciences of the Czech Republic, Bělidla 986/4a, 60300 Brno, Czech Republic;
- Faculty of Science, Institute for Environmental Studies, Charles University, Benátská 2, 12801 Prague, Czech Republic
| | - Spyros Tsiftsis
- Department of Forest and Natural Environment Sciences, International Hellenic University, GR-66100 Drama, Greece;
| | - Pavel Kindlmann
- Global Change Research Institute, Academy of Sciences of the Czech Republic, Bělidla 986/4a, 60300 Brno, Czech Republic;
- Faculty of Science, Institute for Environmental Studies, Charles University, Benátská 2, 12801 Prague, Czech Republic
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20
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Shao SC, Luo Y, Jacquemyn H. Co-Cultures of Mycorrhizal Fungi Do Not Increase Germination and Seedling Development in the Epiphytic Orchid Dendrobium nobile. FRONTIERS IN PLANT SCIENCE 2020; 11:571426. [PMID: 33193505 PMCID: PMC7644947 DOI: 10.3389/fpls.2020.571426] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 09/29/2020] [Indexed: 05/27/2023]
Abstract
Orchids are highly dependent on mycorrhizal fungi for seed germination and subsequent growth to a seedling as they provide essential carbon, water, and mineral nutrients to developing seeds. Although there is mounting evidence that orchid seeds are often colonized by multiple fungi simultaneously, most in vitro germination experiments focus on mycorrhizal monocultures and little is known about how mycorrhizal assemblages affect seed germination and growth of seedlings. In this study, we compared the effects of mycorrhizal monocultures and co-cultures on seed germination and seedling growth of the epiphytic orchid Dendrobium nobile. In situ baiting was used to isolate mycorrhizal fungi from protocorms for germination experiments. Germination experiments were conducted under two light regimes for 90 days. In total, five fungal strains were isolated from protocorms of D. nobile, indicating that the species was not highly specific to its fungal partners. Four strains (JC-01, JC-02, JC-04, and JC-05) belonged to the Serendipitaceae and one (JC-03) to the Tulasnellaceae. In vitro germination experiments showed that germination percentages were higher under light-dark conditions than under complete dark conditions, supporting previous findings that light facilitates germination in epiphytic orchids. While all strains were able to induce protocorm formation and growth into the seedling stage, large differences between fungal strains were observed. Co-cultures did not result in significantly higher seed germination percentages and seedling development than monocultures. Taken together, these results demonstrate that effects of fungal assemblages are not predictable from those of component species, and that more work is needed to better understand the role of fungal assemblages determining seed germination and subsequent growth under natural conditions.
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Affiliation(s)
- Shi-Cheng Shao
- Gardening and Horticulture Department, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Yan Luo
- Gardening and Horticulture Department, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, China
| | - Hans Jacquemyn
- Department of Biology, Plant Conservation and Population Biology, KU Leuven, Leuven, Belgium
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21
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Reiter N, Phillips RD, Swarts ND, Wright M, Holmes G, Sussmilch FC, Davis BJ, Whitehead MR, Linde CC. Specific mycorrhizal associations involving the same fungal taxa in common and threatened Caladenia (Orchidaceae): implications for conservation. ANNALS OF BOTANY 2020; 126:943-955. [PMID: 32574356 PMCID: PMC7539350 DOI: 10.1093/aob/mcaa116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 06/18/2020] [Indexed: 05/04/2023]
Abstract
BACKGROUND AND AIMS In orchid conservation, quantifying the specificity of mycorrhizal associations, and establishing which orchid species use the same fungal taxa, is important for sourcing suitable fungi for symbiotic propagation and selecting sites for conservation translocation. For Caladenia subgenus Calonema (Orchidaceae), which contains 58 threatened species, we ask the following questions. (1) How many taxa of Serendipita mycorrhizal fungi do threatened species of Caladenia associate with? (2) Do threatened Caladenia share orchid mycorrhizal fungi with common Caladenia? (3) How geographically widespread are mycorrhizal fungi associated with Caladenia? METHODS Fungi were isolated from 127 Caladenia species followed by DNA sequencing of the internal transcibed spacer (ITS) sequence locus. We used a 4.1-6 % sequence divergence cut-off range to delimit Serendipita operational taxonomic units (OTUs). We conducted trials testing the ability of fungal isolates to support germination and plant growth. A total of 597 Serendipita isolates from Caladenia, collected from across the Australian continent, were used to estimate the geographic range of OTUs. KEY RESULTS Across the genus, Caladenia associated with ten OTUs of Serendipita (Serendipitaceae) mycorrhizal fungi. Specificity was high, with 19 of the 23 threatened Caladenia species sampled in detail associating solely with OTU A, which supported plants from germination to adulthood. The majority of populations of Caladenia associated with one OTU per site. Fungal sharing was extensive, with 62 of the 79 Caladenia sampled in subgenus Calonema associating with OTU A. Most Serendipita OTUs were geographically widespread. CONCLUSIONS Mycorrhizal fungi can be isolated from related common species to propagate threatened Caladenia. Because of high specificity of most Caladenia species, only small numbers of OTUs typically need to be considered for conservation translocation. When selecting translocation sites, the geographic range of the fungi is not a limiting factor, and using related Caladenia species to infer the presence of suitable fungal OTUs may be feasible.
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Affiliation(s)
- Noushka Reiter
- Royal Botanic Gardens Victoria, Corner of Ballarto Road and Botanic Drive, Cranbourne, Victoria, Australia
- Ecology and Evolution, Research School of Biology, ANU College of Science, RN Robertson Building, 46 Sullivans Creek Road, The Australian National University, Canberra, ACT, Australia
| | - Ryan D Phillips
- Ecology and Evolution, Research School of Biology, ANU College of Science, RN Robertson Building, 46 Sullivans Creek Road, The Australian National University, Canberra, ACT, Australia
- Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria, Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions, Kattidj Close Kings Park, WA, Australia
| | - Nigel D Swarts
- Royal Tasmanian Botanical Gardens, Queens Domain, Hobart, Tasmania, Australia
- Tasmanian Institute of Agriculture, University of Tasmania, Sandy Bay, Tasmania, Australia
| | - Magali Wright
- Royal Tasmanian Botanical Gardens, Queens Domain, Hobart, Tasmania, Australia
| | - Gareth Holmes
- Royal Botanic Gardens Victoria, Corner of Ballarto Road and Botanic Drive, Cranbourne, Victoria, Australia
| | - Frances C Sussmilch
- Kings Park Science, Department of Biodiversity Conservation and Attractions, Kattidj Close Kings Park, WA, Australia
| | - Belinda J Davis
- Kings Park Science, Department of Biodiversity Conservation and Attractions, Kattidj Close Kings Park, WA, Australia
| | - Michael R Whitehead
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Celeste C Linde
- Ecology and Evolution, Research School of Biology, ANU College of Science, RN Robertson Building, 46 Sullivans Creek Road, The Australian National University, Canberra, ACT, Australia
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22
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Phillips RD, Reiter N, Peakall R. Orchid conservation: from theory to practice. ANNALS OF BOTANY 2020; 126:345-362. [PMID: 32407498 PMCID: PMC7424752 DOI: 10.1093/aob/mcaa093] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 05/07/2020] [Indexed: 05/21/2023]
Abstract
BACKGROUND Given the exceptional diversity of orchids (26 000+ species), improving strategies for the conservation of orchids will benefit a vast number of taxa. Furthermore, with rapidly increasing numbers of endangered orchids and low success rates in orchid conservation translocation programmes worldwide, it is evident that our progress in understanding the biology of orchids is not yet translating into widespread effective conservation. SCOPE We highlight unusual aspects of the reproductive biology of orchids that can have important consequences for conservation programmes, such as specialization of pollination systems, low fruit set but high seed production, and the potential for long-distance seed dispersal. Further, we discuss the importance of their reliance on mycorrhizal fungi for germination, including quantifying the incidence of specialized versus generalized mycorrhizal associations in orchids. In light of leading conservation theory and the biology of orchids, we provide recommendations for improving population management and translocation programmes. CONCLUSIONS Major gains in orchid conservation can be achieved by incorporating knowledge of ecological interactions, for both generalist and specialist species. For example, habitat management can be tailored to maintain pollinator populations and conservation translocation sites selected based on confirmed availability of pollinators. Similarly, use of efficacious mycorrhizal fungi in propagation will increase the value of ex situ collections and likely increase the success of conservation translocations. Given the low genetic differentiation between populations of many orchids, experimental genetic mixing is an option to increase fitness of small populations, although caution is needed where cytotypes or floral ecotypes are present. Combining demographic data and field experiments will provide knowledge to enhance management and translocation success. Finally, high per-fruit fecundity means that orchids offer powerful but overlooked opportunities to propagate plants for experiments aimed at improving conservation outcomes. Given the predictions of ongoing environmental change, experimental approaches also offer effective ways to build more resilient populations.
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Affiliation(s)
- Ryan D Phillips
- Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria, Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions, Kings Park, WA, Australia
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Noushka Reiter
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
- Royal Botanic Gardens Victoria, Corner of Ballarto Road and Botanic Drive, Cranbourne, VIC, Australia
| | - Rod Peakall
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, Australia
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23
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Is the Distribution of Two Rare Orchis Sister Species Limited by Their Main Mycobiont? DIVERSITY 2020. [DOI: 10.3390/d12070262] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
As orchids rely on their mycorrhizal fungi for nutrient supply, their spatial range is dependent on the distribution of orchid mycorrhizal (OM) fungi. We addressed possible correlations between mycorrhizal specificity and the geographic distribution of orchids and OM fungi in three populations of the rare sister species Orchis patens and O. canariensis. Metabarcoding of the fungal ITS2 region indicated that, although adult plants of either species were colonized by several ceratobasidioid, tulasnelloid, sebacinoid and serendipitoid fungi, the mycobiont spectra were dominated by Tulasnella helicospora (which occurred in 100% of examined plants with high read numbers), which is a globally distributed fungus. In vitro assays with a T. helicospora isolate obtained from O. patens indicated the effectiveness of this OM fungus at germinating seeds of its native host. At a local scale, higher read numbers for T. helicospora were found in soil samples collected underneath O. patens roots than at locations unoccupied by the orchid. Although these findings suggest that the geographical pattern of the main fungal symbiont does not limit the distribution of O. patens and O. canariensis at this scale, the actual causal link between orchid and OM fungal occurrence/abundance still needs to be better understood.
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Thixton HL, Esselman EJ, Corey LL, Zettler LW. Further evidence of Ceratobasidium D.P. Rogers (Basidiomycota) serving as the ubiquitous fungal associate of Platanthera leucophaea (Orchidaceae) in the North American tallgrass prairie. BOTANICAL STUDIES 2020; 61:12. [PMID: 32297130 PMCID: PMC7158956 DOI: 10.1186/s40529-020-00289-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 04/04/2020] [Indexed: 05/04/2023]
Abstract
BACKGROUND In the United States and Canada, ca. one-half of native orchid species are now threatened with extinction. A number of these species are restricted to tallgrass prairies of central North America, such as the Eastern Prairie Fringed Orchid, Platanthera leucophaea (Nutt.) Lindl.-a U.S. Federally threatened species. RESULTS We provide new records of fungi recovered from roots of P. leucophaea and five other orchid species inhabiting prairie sites in Illinois and neighboring states during a 10-year period (2008-2017). A total of 39 fungal endophytes were isolated from Cypripedium candidum (1), Platanthera lacera (1), P. leucophaea (32), P. peramoena (3), Spiranthes lacera (1), and S. magnicamporum (1), 31 (79%) of which were assignable to Ceratobasidium and the remainder to Tulasnella. These fungi were acquired from 16 different sites, 13 of which are new records including two new state records (Iowa, Wisconsin). Molecular analysis revealed that some Ceratobasidium strains were virtually identical despite being geographically isolated by > 300 km. CONCLUSIONS This study, encompassing a decade of work, confirms that Platanthera leucophaea is a mycorrhizal specialist with heavy reliance on Ceratobasidium with the tallgrass prairie ecosystem of North America. Our isolation of Ceratobasidium from P. leucophaea spanning additional sites suggests that the association is widespread. Such information should provide conservationists and land managers with more confidence in developing protocols that facilitate the long-term conservation of this prairie orchid.
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Affiliation(s)
- Hana L. Thixton
- Department of Biology, Southern Illinois University Edwardsville, 1 Hairpin Dr., Edwardsville, IL 62025 USA
- Department of Biology, Illinois College, 1101 W College Ave., Jacksonville, IL 62650 USA
- Present Address: Department of Biology, West Virginia University, P.O Box 6057, Morgantown, WV 26506 USA
| | - Elizabeth J. Esselman
- Department of Biology, Southern Illinois University Edwardsville, 1 Hairpin Dr., Edwardsville, IL 62025 USA
| | - Laura L. Corey
- Department of Biology, Illinois College, 1101 W College Ave., Jacksonville, IL 62650 USA
| | - Lawrence W. Zettler
- Department of Biology, Illinois College, 1101 W College Ave., Jacksonville, IL 62650 USA
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Figura T, Weiser M, Ponert J. Orchid seed sensitivity to nitrate reflects habitat preferences and soil nitrate content. PLANT BIOLOGY (STUTTGART, GERMANY) 2020; 22:21-29. [PMID: 31509637 DOI: 10.1111/plb.13044] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Accepted: 08/22/2019] [Indexed: 05/04/2023]
Abstract
Orchids are distributed around the world, however, the factors shaping their specific distribution and habitat preferences are largely unknown. Moreover, many orchids are at risk of becoming threatened as landscapes change, sometimes declining without apparent reason. One important factor affecting plant distribution is nutrient levels in the environment. Nitrates can inhibit not only orchid growth and persistence, but also seed germination. We used in vitro axenic cultures to exactly determine the germination sensitivity of seven orchid species to nitrates and correlated this with soil properties of the natural sites and with the species' habitat preferences. We found high variation in response to nitrate between species. Orchids from oligotrophic habitats were highly sensitive, while orchids from more eutrophic habitats were almost insensitive. Sensitivity to nitrate was also associated with soil parameters that indicated a higher nitrification rate. Our results indicate that nitrate can affect orchid distribution via direct inhibition of seed germination. Nitrate levels in soils are increasing rapidly due to intensification of agricultural processes and concurrent soil pollution, and we propose this increase could cause a decline in some orchid species.
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Affiliation(s)
- T Figura
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
- Institut de Systématique, Évolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, Paris, France
| | - M Weiser
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic
| | - J Ponert
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
- Prague Botanical Garden, Prague, Czech Republic
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Low mycorrhizal diversity in the endangered and rare orchids Bipinnula volckmannii and B. apinnula of Central Chile. Symbiosis 2019. [DOI: 10.1007/s13199-019-00648-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Oktalira FT, Whitehead MR, Linde CC. Mycorrhizal specificity in widespread and narrow-range distributed Caladenia orchid species. FUNGAL ECOL 2019. [DOI: 10.1016/j.funeco.2019.100869] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Four Tulasnella taxa associated with populations of the Australian evergreen terrestrial orchid Cryptostylis ovata. Fungal Biol 2019; 124:24-33. [PMID: 31892374 DOI: 10.1016/j.funbio.2019.10.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 10/11/2019] [Accepted: 10/15/2019] [Indexed: 11/23/2022]
Abstract
Of the more than 400 indigenous orchid species in Western Australia, Cryptostylis ovata is the only species that retains its leaves all year round. It exists as a terrestrial herb and occasionally as an epiphyte in forested areas. Like all terrestrial orchids, C. ovata plants associate with mycorrhizal fungi, but their identities have not previously been investigated. Fungi were isolated from pelotons in rhizomes collected from three southern and two northern populations of C. ovata on six occasions over two years. Phylogenetic analysis of ITS sequences temporally and spatially revealed that all the fungal isolates were of Tulasnella species of four distinct groups. One Tulasnella group was present only in the three southern orchid populations, and it closely resembled T. prima isolates previously described from Chiloglottis sp. orchids from eastern Australia. Isolates collected from plants in the two northern populations were of three undescribed Tulasnella groups. Analysis of intra-group diversity using inter-simple sequence repeat markers revealed that plants were usually colonised by a single genotype of Tulasnella at each sampling period, and this genotype usually, but not always, persisted with the host plant over both years tested.
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Kaur J, Andrews L, Sharma J. High specificity of a rare terrestrial orchid toward a rare fungus within the North American tallgrass prairie. Fungal Biol 2019; 123:895-904. [PMID: 31733732 DOI: 10.1016/j.funbio.2019.09.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/17/2019] [Accepted: 09/24/2019] [Indexed: 10/25/2022]
Abstract
The Orchidaceae are globally distributed and represent a diverse lineage of obligate mycotrophic plants. Given their dependence on symbiotic fungi for germination and/or plant development, fungal community structure in substrates is expected to influence the distribution and persistence of orchid species. Yet, simultaneous characterization of orchid mycorrhizal fungal (OMF) communities in roots and in soil is rarely reported. To explain the co-distributions of OMF in roots, orchid-occupied, and bulk soil, we characterized mycorrhizal fungi associated with Platanthera praeclara over multiple years across its entire natural distribution within the North American tallgrass prairie. Root derived OMF communities included 24 Ceratobasidiaceae and 7 Tulasnellaceae operational taxonomic units (OTUs) though the orchid exhibited high spatio-temporal specificity toward a single Ceratobasidiaceae OTU, which was strongly stable across population sizes and phenological stages of the sampled individuals. The preferred OMF OTUs were primarily restricted to orchid-occupied locations while infrequent or absent in bulk soil. Variation in soil OMF assemblies was explained most by soil moisture, magnesium, manganese, and clay. In this first study of coupled root and soil OMF communities across a threatened grassland ecosystem, we report a strong relationship, further nuanced by soil chemistry, between a rare fungus and a rare orchid.
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Affiliation(s)
- Jaspreet Kaur
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, 79409, USA
| | - Lela Andrews
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Jyotsna Sharma
- Department of Plant and Soil Science, Texas Tech University, Lubbock, TX, 79409, USA.
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Mushegian AA, Tougeron K. Animal-Microbe Interactions in the Context of Diapause. THE BIOLOGICAL BULLETIN 2019; 237:180-191. [PMID: 31714855 DOI: 10.1086/706078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Dormancy and diapause are key adaptations in many organisms, enabling survival of temporarily or seasonally unsuitable environmental conditions. In this review, we examine how our understanding of programmed developmental and metabolic arrest during diapause intersects with the increasing body of knowledge about animal co-development and co-evolution with microorganisms. Host-microbe interactions are increasingly understood to affect a number of metabolic, physiological, developmental, and behavioral traits and to mediate adaptations to various environments. Therefore, it is timely to consider how microbial factors might affect the expression and evolution of diapause in a changing world. We examine how a range of host-microbe interactions, from pathogenic to mutualistic, may have an impact on diapause phenotypes. Conversely, we examine how the discontinuities that diapause introduces into animal host generations can affect the ecology of microbial communities and the evolution of host-microbe interactions. We discuss these issues as they relate to physiology, evolution of development, local adaptation, disease ecology, and environmental change. Finally, we outline research questions that bridge the historically distinct fields of seasonal ecology and host-microbe interactions.
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Gomes SIF, van Bodegom PM, Merckx VSFT, Soudzilovskaia N. Environmental drivers for cheaters of arbuscular mycorrhizal symbiosis in tropical rainforests. THE NEW PHYTOLOGIST 2019; 223:1575-1583. [PMID: 31038750 PMCID: PMC6771734 DOI: 10.1111/nph.15876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 04/15/2019] [Indexed: 05/22/2023]
Abstract
Hundreds of nonphotosynthetic mycoheterotrophic plant species cheat the arbuscular mycorrhizal symbiosis. Their patchy local occurrence suggests constraints by biotic and abiotic factors, among which the role of soil chemistry and nutrient status has not been investigated. Here, we examine the edaphic drivers predicting the local-scale distribution of mycoheterotrophic plants in two lowland rainforests in South America. We compared soil chemistry and nutrient status in plots where mycoheterotrophic plants were present with those without these plants. Soil pH, soil nitrate, and the interaction between soil potassium and nitrate concentrations were the best predictors for the occurrence of mycoheterotrophic plants in these tropical rainforests. Mycoheterotrophic plant occurrences decreased with a rise in each of these predictors. This indicates that these plants are associated with low-fertility patches. Such low-fertility conditions coincide with conditions that potentially favour a weak mutualism between plants and arbuscular mycorrhizal fungi according to the trade balance model. Our study points out which soil properties favour the cheating of arbuscular mycorrhizal networks in tropical forests. The patchy occurrence of mycoheterotrophic plants suggests that local soil heterogeneity causes the stability of arbuscular mycorrhizal networks to vary at a very small scale.
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Affiliation(s)
- Sofia I. F. Gomes
- Institute of Environmental SciencesLeiden University2333 CCLeidenthe Netherlands
- Understanding Evolution GroupNaturalis Biodiversity Center2332 AALeidenthe Netherlands
| | - Peter M. van Bodegom
- Institute of Environmental SciencesLeiden University2333 CCLeidenthe Netherlands
| | - Vincent S. F. T. Merckx
- Understanding Evolution GroupNaturalis Biodiversity Center2332 AALeidenthe Netherlands
- Department of Evolutionary and Population BiologyInstitute for Biodiversity and Ecosystem DynamicsUniversity of AmsterdamAmsterdamthe Netherlands
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Reiter N, Lawrie AC, Linde CC. Matching symbiotic associations of an endangered orchid to habitat to improve conservation outcomes. ANNALS OF BOTANY 2018; 122:947-959. [PMID: 29897399 PMCID: PMC6266109 DOI: 10.1093/aob/mcy094] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 05/13/2018] [Indexed: 05/08/2023]
Abstract
Background and Aims An understanding of mycorrhizal variation, orchid seed germination temperature and the effect of co-occurring plant species could be critical for optimizing conservation translocations of endangered plants with specialized mycorrhizal associations. Methods Focusing on the orchid Thelymitra epipactoides, we isolated mycorrhizal fungi from ten plants within each of three sites; Shallow Sands Woodland (SSW), Damp Heathland (DH) and Coastal Heathland Scrub (CHS). Twenty-seven fungal isolates were tested for symbiotic germination under three 24 h temperature cycles: 12 °C for 16 h-16 °C for 8 h, 16 °C for 16 h-24 °C for 8 h or 27 °C constant. Fungi were sequenced using the internal transcribed spacer (ITS), nuclear large subunit 1 (nLSU1), nLSU2 and mitochondrial large rRNA gene (mtLSU). Orchids were grown to maturity and co-planted with each of ten associated plant species in a glasshouse experiment with tuber width measured at 12 months after co-planting. Key Results Two Tulasnella fungal lineages were isolated and identified by phylogenetic analyses, operational taxonomic unit 1 (OTU1) and 'T. asymmetrica'. Fungal lineages were specific to sites and did not co-occur. OTU1 (from the SSW site) germinated seed predominantly at 12-16 °C (typical of autumn-winter temperature) whereas 'T. asymmetrica' (from the DH and CHS sites) germinated seed across all three temperature ranges. There was no difference in the growth of adult orchids germinated with different OTUs. There was a significant reduction in tuber size of T. epipactoides when co-planted with six of the commonly co-occurring plant species. Conclusions We found that orchid fungal lineages and their germination temperature can change with habitat, and established that translocation sites can be optimized with knowledge of co-occurring plant interactions. For conservation translocations, particularly under a changing climate, we recommend that plants should be grown with mycorrhizal fungi tailored to the recipient site.
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Affiliation(s)
- Noushka Reiter
- Royal Botanic Gardens Victoria, Cnr Ballarto Rd and Botanic Drive, Cranbourne, VIC, Australia
- Ecology and Evolution, Research School of Biology, College of Science, The Australian National University, Canberra, ACT, Australia
| | - Ann C Lawrie
- School of Science, RMIT University (Bundoora West Campus), Bundoora, VIC, Australia
| | - Celeste C Linde
- Ecology and Evolution, Research School of Biology, College of Science, The Australian National University, Canberra, ACT, Australia
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Gaskett AC, Gallagher RV. Orchid diversity: Spatial and climatic patterns from herbarium records. Ecol Evol 2018; 8:11235-11245. [PMID: 30519440 PMCID: PMC6262934 DOI: 10.1002/ece3.4598] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 09/10/2018] [Accepted: 09/16/2018] [Indexed: 01/31/2023] Open
Abstract
AIM We test for spatial and climatic patterns of diversification in the Orchidaceae, an angiosperm family characterized by high levels of species diversity and rarity. Globally, does orchid diversity correlate with land area? In Australia, does diversity correlate with herbarium collecting effort, range size, or climate niche breadth? Where are Australia's orchids distributed spatially, in protected areas, and in climate space? LOCATION Global, then Australia. METHODS We compared orchid diversity with land area for continents and recognized orchid diversity hotspots. Then, we used cleaned herbarium records to compare collecting effort (for Australian Orchidaceae vs. all other plant families, and also among orchid genera). Spatial and climate distributions were mapped to determine orchids' coverage in the protected area network, range sizes, and niche breadths. RESULTS Globally, orchid diversity does not correlate with land area (depauperate regions are the subantarctic: 10 species, and northern North America: 394 species). Australian herbarium records and collecting effort generally reflect orchid species diversity (1,583 spp.), range sizes, and niche breadths. Orchids are restricted to 13% of Australia's landmass with 211 species absent from any protected areas. Species richness is the greatest in three biomes with high general biodiversity: Temperate (especially southwest and southeast Australia), Tropical, and Subtropical (coastal northern Queensland). Absence from the Desert is consistent with our realized climate niche-orchids avoid high temperature/low rainfall environments. Orchids have narrower range sizes than nonorchid species. Highly diverse orchid genera have narrower rainfall breadths than less diverse genera. MAIN CONCLUSIONS Herbarium data are adequate for testing hypotheses about Australian orchids. Distribution is likely driven by environmental factors. In contrast, diversification did not correlate with increases in range size, rainfall, or temperature breadths, suggesting speciation does not occur via invasion and local adaptation to new habitats. Instead, diversification may rely on access to extensive obligate symbioses with mycorrhizae and/or pollinators.
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Affiliation(s)
- Anne C. Gaskett
- School of Biological SciencesThe University of AucklandAucklandNew Zealand
| | - Rachael V. Gallagher
- Department of Biological SciencesMacquarie UniversitySydneyNew South WalesAustralia
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Pecoraro L, Caruso T, Cai L, Gupta VK, Liu ZJ. Fungal networks and orchid distribution: new insights from above- and below-ground analyses of fungal communities. IMA Fungus 2018; 9:1-11. [PMID: 30018868 PMCID: PMC6048571 DOI: 10.5598/imafungus.2018.09.01.01] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 01/27/2018] [Indexed: 01/27/2023] Open
Abstract
Orchids are critically dependent on fungi for seedling establishment and growth, so the distribution and diversity of orchids might depend on the associated fungal communities. We characterised the communities associated with eight orchid species in three Mediterranean protected areas, using a combination of above-ground analyses of sporophores and below-ground molecular analyses of orchid root samples. In three years of sporophore collection in 25 plots around flowering orchid plants, 268 macrofungal species belonging to 84 genera were observed. Statistical analyses indicated a correlation between macrofungal diversity and orchid community variation, regardless of the effect of environmental and spatial factors characterizing the investigated orchid sites. Fungal ITS-DNA PCR amplification, cloning, and sequencing revealed Rhizoctonia-like fungi belonging to Ceratobasidiaceae (26 %), Tulasnellaceae (22.5 %), and Sebacinaceae (3.5 %), as well as other basidiomycetes and ascomycetes, in the roots of 99 orchid plants. Mycorrhizal specificity was low but co-occurring orchid species showed preferences for different partners. The diverse macrofungal communities found in the sites may contribute to orchid community variation without colonizing the orchid roots. Molecular analyses revealed a segregation of associated fungi, which may contribute to Mediterranean orchid coexistence in nature.
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Affiliation(s)
- Lorenzo Pecoraro
- Shenzhen Key Laboratory for Orchid Conservation and Utilization, The National Orchid Conservation Center of China and The Orchid Conservation and Research Center of Shenzhen, 518114 Shenzhen, China
- Center for Biotechnology & BioMedicine and Division of Life & Health Sciences, Graduate School at Shenzhen, Tsinghua University, 518055 Shenzhen, China
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Tancredi Caruso
- School of Biological Sciences, Queen's University of Belfast, BT9 7BL Belfast, Northern Ireland
| | - Lei Cai
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China
| | - Vijai Kumar Gupta
- Department of Chemistry and Biotechnology, ERA Chair of Green Chemistry, School of Science, Tallinn University of Technology, 12618 Tallinn, Estonia
| | - Zhong-Jian Liu
- Shenzhen Key Laboratory for Orchid Conservation and Utilization, The National Orchid Conservation Center of China and The Orchid Conservation and Research Center of Shenzhen, 518114 Shenzhen, China
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Dornburg A, Townsend JP, Wang Z. Maximizing Power in Phylogenetics and Phylogenomics: A Perspective Illuminated by Fungal Big Data. ADVANCES IN GENETICS 2017; 100:1-47. [PMID: 29153398 DOI: 10.1016/bs.adgen.2017.09.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Since its original inception over 150 years ago by Darwin, we have made tremendous progress toward the reconstruction of the Tree of Life. In particular, the transition from analyzing datasets comprised of small numbers of loci to those comprised of hundreds of loci, if not entire genomes, has aided in resolving some of the most vexing of evolutionary problems while giving us a new perspective on biodiversity. Correspondingly, phylogenetic trees have taken a central role in fields that span ecology, conservation, and medicine. However, the rise of big data has also presented phylogenomicists with a new set of challenges to experimental design, quantitative analyses, and computation. The sequencing of a number of very first genomes presented significant challenges to phylogenetic inference, leading fungal phylogenomicists to begin addressing pitfalls and postulating solutions to the issues that arise from genome-scale analyses relevant to any lineage across the Tree of Life. Here we highlight insights from fungal phylogenomics for topics including systematics and species delimitation, ecological and phenotypic diversification, and biogeography while providing an overview of progress made on the reconstruction of the fungal Tree of Life. Finally, we provide a review of considerations to phylogenomic experimental design for robust tree inference. We hope that this special issue of Advances in Genetics not only excites the continued progress of fungal evolutionary biology but also motivates the interdisciplinary development of new theory and methods designed to maximize the power of genomic scale data in phylogenetic analyses.
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Affiliation(s)
- Alex Dornburg
- North Carolina Museum of Natural Sciences, Raleigh, NC, United States
| | | | - Zheng Wang
- Yale University, New Haven, CT, United States.
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Mushegian AA, Walser JC, Sullam KE, Ebert D. The microbiota of diapause: How host-microbe associations are formed after dormancy in an aquatic crustacean. J Anim Ecol 2017; 87:400-413. [DOI: 10.1111/1365-2656.12709] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 05/08/2017] [Indexed: 01/28/2023]
Affiliation(s)
| | - Jean-Claude Walser
- Zoological Institute; University of Basel; Basel Switzerland
- Genetic Diversity Centre; ETH Zürich; Zürich Switzerland
| | - Karen E. Sullam
- Zoological Institute; University of Basel; Basel Switzerland
| | - Dieter Ebert
- Zoological Institute; University of Basel; Basel Switzerland
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Ruibal MP, Triponez Y, Smith LM, Peakall R, Linde CC. Population structure of an orchid mycorrhizal fungus with genus-wide specificity. Sci Rep 2017; 7:5613. [PMID: 28717170 PMCID: PMC5514033 DOI: 10.1038/s41598-017-05855-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 06/02/2017] [Indexed: 12/02/2022] Open
Abstract
Fundamental life history processes of mycorrhizal fungi with inconspicuous fruiting bodies can be difficult to elucidate. In this study we investigated the species identities and life history of the orchid mycorrhizal Tulasnella fungi, which associate with the south eastern Australia orchid genus Chiloglottis. Tulasnella prima was the primary partner and was found to be associated with all 17 Chiloglottis species across a range of >1000 km, and to occur in the two edaphic conditions investigated (soil and sphagnum hammocks). Another Tulasnella species (T. sphagneti) appears to be restricted to moist conditions of alpine sphagnum hammocks. The population genetic structure of the widespread species T. prima, was investigated at 10 simple sequence repeat (SSR) markers and at four cross-amplified SSR loci for T. sphagneti. For both taxa, no sharing of multilocus genotypes was found between sites, but clones were found within sites. Evidence for inbreeding within T. prima was found at 3 of 5 sites. Significant genetic differentiation was found within and between taxa. Significant local positive spatial genetic autocorrelation was detected among non-clonal isolates at the scale of two metres. Overall, the population genetic patterns indicated that in Tulasnella mating occurs by inbreeding and dispersal is typically restricted to short-distances.
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Affiliation(s)
- M P Ruibal
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Y Triponez
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - L M Smith
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - R Peakall
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - C C Linde
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia.
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Evaluating multilocus Bayesian species delimitation for discovery of cryptic mycorrhizal diversity. FUNGAL ECOL 2017. [DOI: 10.1016/j.funeco.2016.11.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
BACKGROUND Due in great part to their often complex interactions with mycorrhizal fungi, pollinators and host trees, Orchidaceae present particular challenges for conservation. Furthermore, orchids, as potentially the largest family of angiosperms with >26000 species, species complexes and frequent hybrid formation, are complex to catalogue. Following a highlight in 2015, a further seven papers focusing on orchids, their interactions with beneficial organisms, pollinators and mycorrhiza, and other factors relating to their conservation, including threats from human utilization and changing land use, are presented here. CONCLUSIONS The production of an online flora of all known plants and an assessment of the conservation status of all known plant species as far as possible, to guide conservation action are the first two targets of the Global Strategy for Plant Conservation Without knowing how many species there are and how they should be circumscribed, neither of these targets is achievable. Orchids are a fascinating subject for fundamental research with rapid species evolution, specific organ structure and development, but they also suffer from high levels of threat. Effective orchid conservation must take account of the beneficial interactions with fungi and pollinators and the potentially detrimental effects of over-collection and changes in land use.
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Affiliation(s)
- Michael F Fay
- Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, UK and School of Plant Biology, University of Western Australia, Crawley, WA 6009, Australia
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Weiß M, Waller F, Zuccaro A, Selosse MA. Sebacinales - one thousand and one interactions with land plants. THE NEW PHYTOLOGIST 2016; 211:20-40. [PMID: 27193559 DOI: 10.1111/nph.13977] [Citation(s) in RCA: 172] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 02/05/2016] [Indexed: 05/20/2023]
Abstract
20 I 21 II 21 III 23 IV 29 V 33 VI 35 36 36 References 36 SUMMARY: Root endophytism and mycorrhizal associations are complex derived traits in fungi that shape plant physiology. Sebacinales (Agaricomycetes, Basidiomycota) display highly diverse interactions with plants. Although early-diverging Sebacinales lineages are root endophytes and/or have saprotrophic abilities, several more derived clades harbour obligate biotrophs forming mycorrhizal associations. Sebacinales thus display transitions from saprotrophy to endophytism and to mycorrhizal nutrition within one fungal order. This review discusses the genomic traits possibly associated with these transitions. We also show how molecular ecology revealed the hyperdiversity of Sebacinales and their evolutionary diversification into two sister families: Sebacinaceae encompasses mainly ectomycorrhizal and early-diverging saprotrophic species; the second family includes endophytes and lineages that repeatedly evolved ericoid, orchid and ectomycorrhizal abilities. We propose the name Serendipitaceae for this family and, within it, we transfer to the genus Serendipita the endophytic cultivable species Piriformospora indica and P. williamsii. Such cultivable Serendipitaceae species provide excellent models for root endophytism, especially because of available genomes, genetic tractability, and broad host plant range including important crop plants and the model plant Arabidopsis thaliana. We review insights gained with endophytic Serendipitaceae species into the molecular mechanisms of endophytism and of beneficial effects on host plants, including enhanced resistance to abiotic and pathogen stress.
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Affiliation(s)
- Michael Weiß
- Steinbeis-Innovationszentrum Organismische Mykologie und Mikrobiologie, Vor dem Kreuzberg 17, 72070, Tübingen, Germany
- Department of Biology, University of Tübingen, Auf der Morgenstelle 1, 72076, Tübingen, Germany
| | - Frank Waller
- Pharmaceutical Biology, Julius von Sachs Institute for Biosciences, Biocenter, Würzburg University, Julius-von-Sachs Platz 2, 97082, Würzburg, Germany
| | - Alga Zuccaro
- Botanical Institute, Cluster of Excellence on Plant Sciences (CEPLAS), BioCenter, University of Cologne, 50674, Cologne, Germany
- Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Marc-André Selosse
- Département Systématique et Evolution (UMR 7205 ISYEB), Muséum national d'Histoire naturelle, CP 50, 45 rue Buffon, 75005, Paris, France
- Department of Plant Taxonomy and Nature Conservation, University of Gdansk, Gdansk, Poland
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Abstract
Orchidaceae, one of the largest families of flowering plants, present particular challenges for conservation, due in great part to their often complex interactions with mycorrhizal fungi, pollinators and host trees. In this Highlight, we present seven papers focusing on orchids and their interactions and other factors relating to their conservation.
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Affiliation(s)
- Michael F Fay
- Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3DS, UK,
| | - Thierry Pailler
- Peuplements Végétaux et Bioagresseurs en Milieu Tropical, CIRAD-Université de La Réunion, 15 Avenue René Cassin BP 7151, 97715 Saint-Denis, La Réunion, France and
| | - Kingsley W Dixon
- Department of Environment and Agriculture, Curtin University, Kent Street, Bentley, Perth, Western Australia, 6102, Australia
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