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Arifin AR, Reiter NH, May TW, Linde CC. New species of Tulasnella associated with Australian terrestrial orchids in the subtribes Megastylidinae and Thelymitrinae. Mycologia 2022; 114:388-412. [PMID: 35316155 DOI: 10.1080/00275514.2021.2019547] [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: 10/18/2022]
Abstract
Tulasnella (Tulasnellaceae) is a genus of fungus that can form mycorrhizal associations with orchids (Orchidaceae). Here we used molecular phylogenetic analyses and morphological characteristics of pure cultures across four different media to support the description of five new Tulasnella species associated with commonly occurring and endangered Australian orchids. Tulasnella nerrigaensis associates with Calochilus; T. subasymmetrica and T. kiataensis with Thelymitra; and T. korungensis and T. multinucleata with Pyrorchis and Rimacola respectively. The newly described species were primarily delimited by analyses of five loci: nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), C14436 (adenosine triphosphate [ATP] synthase), C4102 (glutamate synthase), C3304 (ATP helicase), and mt large subunit 16S rDNA (mtLSU). Tulasnella subasymmetrica is introduced for some isolates previously identified as T. asymmetrica, and this latter species is characterized from multilocus sequencing of a new isolate that matches ITS sequences from the ex-type culture. Morphological differences between the new species are slight. Tulasnella multinucleata has 6-12 nuclei per hyphal compartment which is the first instance of multinucleate rather than binucleate or trinucleate hyphal compartments in Tulasnella. The formal description of these species of Tulasnella will aid in future evolutionary and ecological studies of orchid-fungal interactions.
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Affiliation(s)
- Arild R Arifin
- Ecology and Evolution, Research School of Biology, the Australian National University, ACT 2601, Canberra, Australia
| | - Noushka H Reiter
- Ecology and Evolution, Research School of Biology, the Australian National University, ACT 2601, Canberra, Australia.,Science Division, Royal Botanic Gardens Victoria, cnr Ballarto Road and Botanic Drive, Cranbourne, 3977, Australia
| | - Tom W May
- Science Division, Royal Botanic Gardens Victoria, Melbourne, 3004, Australia
| | - Celeste C Linde
- Ecology and Evolution, Research School of Biology, the Australian National University, ACT 2601, Canberra, Australia
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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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Arifin AR, May TW, Linde CC. New species of Tulasnella associated with Australian terrestrial orchids in the Cryptostylidinae and Drakaeinae. Mycologia 2020; 113:212-230. [PMID: 33146586 DOI: 10.1080/00275514.2020.1813473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Many orchids have an obligate relationship with Tulasnella mycorrhizal fungi for seed germination and support into adulthood. Despite the importance of Tulasnella as mycorrhizal partners, many species remain undescribed. Here, we use multiple sequence locus phylogenetic analyses to delimit and describe six new Tulasnella species associated with Australian terrestrial orchids from the subtribes Cryptostylidinae and Drakaeinae. Five of the new species, Tulasnella australiensis, T. occidentalis, T. punctata, T. densa, and T. concentrica, all associate with Cryptostylis (Cryptostylidinae), whereas T. rosea associates with Spiculaea ciliata (Drakaeinae). Isolates representing T. australiensis were previously also reported in association with Arthrochilus (Drakaeinae). All newly described Tulasnella species were delimited by phylogenetic analyses of four loci (nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 [ITS], C14436 [ATP synthase], C4102 [glutamate synthase], and mt 16S rDNA [mtLSU]). The pairwise sequence divergence between species for the ITS region ranged from 5.6% to 25.2%, and the maximum sequence divergence within the newly described species ranged from 1.64% to 4.97%. There was a gap in the distribution of within- and between-species pairwise divergences in the region of 4-6%, with only one within-species value of 4.97% (for two T. australiensis isolates) and one between-species value of 5.6% (involving an isolate of T. occidentalis) falling within this region. Based on fluorescence staining, all six new Tulasnella species are binucleate and have septate, cylindrical hyphae. There was some subtle variation in culture morphology, but colony diameter as measured on 3MN+vitamin medium after 6 wk of growth did not differ among species. However, T. australiensis grew significantly (P < 0.02) slower than others on ½ FIM and ¼ potato dextrose agar (PDA) media. Formal description of these Tulasnella species contributes significantly to documentation of Tulasnella diversity and provides names and delimitations to underpin further research on the fungi and their relationships with orchids.
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Affiliation(s)
- Arild R Arifin
- Ecology and Evolution, Research School of Biology, The Australian National University , Canberra, ACT 2601, Australia
| | - Tom W May
- Royal Botanic Gardens Victoria, Birdwood Avenue, Melbourne , VIC 3004, Australia
| | - Celeste C Linde
- Ecology and Evolution, Research School of Biology, The Australian National University , Canberra, ACT 2601, Australia
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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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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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Waud M, Busschaert P, Ruyters S, Jacquemyn H, Lievens B. Impact of primer choice on characterization of orchid mycorrhizal communities using 454 pyrosequencing. Mol Ecol Resour 2014; 14:679-99. [PMID: 24460947 DOI: 10.1111/1755-0998.12229] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 01/07/2014] [Accepted: 01/08/2014] [Indexed: 01/24/2023]
Abstract
Although the number of studies investigating mycorrhizal associations in orchids has increased in recent years, the fungal communities associating with orchids and how they differ between species and sites remain unclear. Recent research has indicated that individual orchid plants may associate with several fungi concurrently, implying that to study mycorrhizal associations in orchids the fungal community should be assessed, rather than the presence of individual dominant fungal species or strains. High-throughput sequencing methods, such as 454 pyrosequencing, are increasingly used as the primary tool for such analyses. However, many studies combine universal primers from previous phylogenetic or ecological studies to generate amplicons suitable for 454 pyrosequencing without first critically evaluating their performance, potentially resulting in biased fungal community descriptions. Here, following in silico primer analysis we evaluated the performance of different combinations of existing PCR primers to characterize orchid mycorrhizal communities using 454 pyrosequencing by analysis of both an artificially assembled community of mycorrhizal fungi isolated from diverse orchid species and root samples from three different orchid species (Anacamptis morio, Ophrys tenthredinifera and Serapias lingua). Our results indicate that primer pairs ITS3/ITS4OF and ITS86F/ITS4, targeting the internal transcribed spacer-2 (ITS-2) region, outperformed other tested primer pairs in terms of number of reads, number of operational taxonomic units recovered from the artificial community and number of different orchid mycorrhizal associating families detected in the orchid samples. Additionally, we show the complementary specificity of both primer pairs, making them highly suitable for tandem use when studying the diversity of orchid mycorrhizal communities.
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Affiliation(s)
- Michael Waud
- Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), Department of Microbial and Molecular Systems (M2S), KU Leuven, Campus De Nayer, B-2860, Sint-Katelijne-Waver, Belgium; Division of Plant Ecology and Systematics, Biology Department, KU Leuven, Kasteelpark Arenberg 31, B-3001, Heverlee, Belgium
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Linde CC, Phillips RD, Crisp MD, Peakall R. Congruent species delineation of Tulasnella using multiple loci and methods. THE NEW PHYTOLOGIST 2014; 201:6-12. [PMID: 24028679 DOI: 10.1111/nph.12492] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Affiliation(s)
- Celeste C Linde
- Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
| | - Ryan D Phillips
- Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
- The Botanic Garden and Parks Authority, Kings Park and Botanic Garden, West Perth, WA, 6005, Australia
- School of Plant Biology, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Michael D Crisp
- Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
| | - Rod Peakall
- Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
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