Codiversification of orchids (Pterostylidinae) and their associated mycorrhizal fungi

2011 ◽  
Vol 59 (5) ◽  
pp. 480 ◽  
Author(s):  
J. Tupac Otero ◽  
Peter H. Thrall ◽  
Mark Clements ◽  
Jeremy J. Burdon ◽  
Joseph T. Miller
Keyword(s):  
Mycorrhizal Fungi ◽  
Mycorrhizal Fungus ◽  
Distinct Group ◽  
Host Group ◽  
Mycorrhizal Associations ◽  
As Species ◽  
Terrestrial Orchids ◽  
Nuclear Its ◽  
Germination Experiments

Fungal symbionts involved in mycorrhizal associations are known to vary considerably in both specificity and the level of benefits conferred on their plant hosts. For orchids, association with a suitable mycorrhizal fungus is vital for successful germination, growth and establishment. Using an evolutionarily distinct group of Australasian terrestrial orchids, the Pterostylidinae (Cranichiadeae: Orchidaceae), we assessed potential codiversification and the level of response between this diverse host group (~250 species) and their associated fungal symbionts. All fungal isolates recovered (~200 from 41 host species covering all major orchid clades) were identified as species of Ceratobasidium, which clustered into strongly supported groups using nuclear (ITS) and mitochondrial (ML 4–5) gene sequences. Three clades within the Pterostylidinae phylogeny showed associations with specific fungal clades. The results suggest the occurrence of local adaptation by the fungal symbionts to the orchid host, particularly in diverse and widespread host taxa. Results of cross-inoculation in vitro germination experiments revealed correlations between certain mycorrhizal fungal clades and particular orchid taxa, with germination generally being most effective when seeds were inoculated with fungal strains from the same clade as found naturally associated with the orchid species. We found only general congruence between the orchid and fungal phylogenies, suggesting that strict codivergerence between these orchids and their mycorrhizal associates has not occurred at the broad level of resolution studied.

Simultaneous encapsulation of seed and mycorrhizal fungi for long-term storage and propagation of terrestrial orchids

2008 ◽  
Vol 56 (7) ◽  
pp. 609 ◽  
Author(s):  
Karen D. Sommerville ◽  
John P. Siemon ◽  
Chris B. Wood ◽  
Catherine A. Offord
Keyword(s):  
Mycorrhizal Fungi ◽  
Ex Situ Conservation ◽  
Alginate Beads ◽  
Ex Situ ◽  
Storage Duration ◽  
Long Term Storage ◽  
Mycorrhizal Associations ◽  
Terrestrial Orchids

Ex situ conservation of threatened terrestrial orchids requires the simultaneous conservation of their mycorrhizal associations. A method for encapsulating both seed and fungi in alginate beads (known as encapsulation–dehydration) was applied to the storage and propagation of two endangered orchid species in NSW, Australia—Pterostylis saxicola D.L.Jones & M.A.Clem. and Diuris arenaria D.L.Jones. We tested the effect of storage duration and temperature on fungal recovery and germination potential in vitro, and recorded survival for seedlings subsequently transferred to potting mix. Storage at 23°C significantly reduced fungal recovery and germination for both species after only 3 months (P < 0.05), whereas storage at 4°C significantly reduced fungal recovery for P. saxicola after 6 months (P < 0.05). Storage for 6 months at −18 and −196°C had no significant effect on the fungal recovery and germination percentages of either species. All beads transferred directly from in vitro culture to potting mix resulted in the establishment of at least one seedling, and production of a healthy tuberoid, when transferred near the commencement of the natural growing season. The encapsulation–dehydration method may have a practical application for use in ex situ conservation of other terrestrial orchids, as well as their mycorrhizal fungi.

scholarly journals Alkaline extract of the seaweed Ascophyllum nodosum stimulates arbuscular mycorrhizal fungi and their endomycorrhization of plant roots

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah Hines ◽  
Timo van der Zwan ◽  
Kevin Shiell ◽  
Katy Shotton ◽  
Balakrishnan Prithiviraj
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Ascophyllum Nodosum ◽  
Tube Length ◽  
Direct Stimulation ◽  
Mycorrhizal Associations ◽  
Stimulation Of

AbstractAscophyllum nodosum extracts (ANE) are well-established plant biostimulants that improve stress tolerance and crop vigour, while also having been shown to stimulate soil microbes. The intersection of these two stimulatory activities, and how they combine to enhance plant health, however, remains poorly understood. In the present study, we aimed to evaluate: (1) the direct effect of ANE on the arbuscular mycorrhizal fungus Rhizophagus irregularis, and (2) whether ANE influences endomycorrhization in plants. ANE enhanced development of R. irregularis in vitro, showing greater spore germination, germ tube length, and hyphal branching. Greenhouse-grown Medicago truncatula drench-treated with ANE formed mycorrhizal associations faster (3.1-fold higher mycorrhization at week 4) and grew larger (29% greater leaf area by week 8) than control plants. Foliar applications of ANE also increased root colonization and arbuscular maturity, but did not appear to enhance plant growth. Nonetheless, following either foliar or drench application, M. truncatula genes associated with establishment of mycorrhizae were expressed at significantly higher levels compared to controls. These results suggest that ANE enhances mycorrhization through both direct stimulation of arbuscular mycorrhizal fungus growth and through stimulation of the plant’s accommodation of the symbiont, together promoting the establishment of this agriculturally vital plant–microbe symbiosis.

In vitro culture of arbuscular mycorrhizal fungus and Frankia for inoculation of micropropagated Casuarina equisetifolia L.

1999 ◽  
Vol 77 (9) ◽  
pp. 1391-1397
Author(s):  
Genevieve Louise Mark ◽  
John E Hooker ◽  
Alexander Hahn ◽  
Chris T Wheeler
Keyword(s):  
Spore Germination ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal Fungus ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Dichlorophenoxyacetic Acid ◽  
Casuarina Equisetifolia ◽  
Half Strength ◽  
2,4 Dichlorophenoxyacetic Acid

Micropropagated, rooted, and calli explants of Casuarina equisetifolia L. were inoculated with Frankia UGL 020605S and the arbuscular mycorrhizal fungus (AMF) Glomus mosseae, in single and dual co-culture, in vitro. Different micropropagation media formulations were evaluated for their capacity to stimulate germination of G. mosseae spores and growth of Frankia. Murashige and Skoog basal nutrient (half strength) medium, supplemented with 6-benzylaminopurine (BAP), 2,4-dichlorophenoxyacetic acid (2,4-D), and pyruvate was selected for the in vitro co-culture of C. equisetifolia callus explants, G. mosseae, and Frankia. This medium (M4) supported 70% AMF spore germination with 44 and 34% of the germinating spores producing single and branched hyphal strands, respectively. Hoaglands (quarter strength, modified by Hoaglands and Arnon (1950)) nutrient medium (M5) with no supplements was selected for the in vitro co-culture of rooted C. equisetifolia explants, G. mosseae, and Frankia and supported 57% AMF spore germination with 29 and 40% of the germinating spores producing single and branched hyphal strands, respectively. Both media supported significant growth of Frankia. In both cases agar was substituted with Terragreen(r). AMF appressoria and intercellular hyphae were observed in rooted C. equisetifolia at 28 days; arbuscule formation occurred at 56 days postinoculation. Frankia infection was evident after 28 days. This was observed in both dual and single in vitro co-cultures. No specific immunofluorescent or immunogold reactions to monoclonal antibodies (mABs) anti-Frankia < 8C5 > and anti-G. mosseae < F5G5 > were evident in C. equisetifolia callus explants.Key words: arbuscular mycorrhizal fungi (AMF), Frankia, Casuarina, micropropagation, immunofluorescent labelling.

scholarly journals Mycorrhizal Fungi Isolated from Native Terrestrial Orchids from Region of La Araucanía, Southern Chile

2020 ◽  
Vol 8 (8) ◽  
pp. 1120
Author(s):  
Hector Herrera ◽  
Tedy Sanhueza ◽  
Rodolfo Martiarena ◽  
Rafael Valadares ◽  
Alejandra Fuentes ◽  
...  
Keyword(s):  
Life Cycle ◽  
Seed Germination ◽  
Threatened Species ◽  
Mycorrhizal Fungi ◽  
Its Region ◽  
Southern Chile ◽  
Mycorrhizal Associations ◽  
Terrestrial Orchids ◽  
Recovery Strategies ◽  
Mycorrhizal Interactions

Mycorrhizal interactions of orchids are influenced by several environmental conditions. Hence, knowledge of mycorrhizal fungi associated with orchids inhabiting different ecosystems is essential to designing recovery strategies for threatened species. This study analyzes the mycorrhizal associations of terrestrial orchids colonizing grassland and understory in native ecosystems of the region of La Araucanía in southern Chile. Mycorrhizal fungi were isolated from peloton-containing roots and identified based on the sequence of the ITS region. Their capacities for seed germination were also investigated. We detected Tulasnella spp. and Ceratobasidium spp. in the pelotons of the analyzed orchids. Additionally, we showed that some Ceratobasidium isolates effectively induce seed germination to differing degrees, unlike Tulasnella spp., which, in most cases, fail to achieve protocorm growth. This process may underline a critical step in the life cycle of Tulasnella-associated orchids, whereas the Ceratobasidium-associated orchids were less specific for fungi and were effectively germinated with mycorrhizal fungi isolated from adult roots.

Scientific approaches to Australian temperate terrestrial orchid conservation

2007 ◽  
Vol 55 (3) ◽  
pp. 293 ◽  
Author(s):  
Mark C. Brundrett
Keyword(s):  
Mycorrhizal Fungi ◽  
Three Dimensions ◽  
Natural Habitats ◽  
Mycorrhizal Associations ◽  
Terrestrial Orchids ◽  
Key Factor ◽  
Orchid Seed ◽  
Declining Populations ◽  
Feral Animals ◽  
Sexually Deceptive Orchids

This review summarises scientific knowledge concerning the mycorrhizal associations, pollination, demographics, genetics and evolution of Australian terrestrial orchids relevant to conservation. The orchid family is highly diverse in Western Australia (WA), with over 400 recognised taxa of which 76 are Declared Rare or Priority Flora. Major threats to rare orchids in WA include habitat loss, salinity, feral animals and drought. These threats require science-based recovery actions resulting from collaborations between universities, government agencies and community groups. Fungal identification by DNA-based methods in combination with compatibility testing by germination assays has revealed a complex picture of orchid–fungus diversity and specificity. The majority of rare and common WA orchids studied have highly specific mycorrhizal associations with fungi in the Rhizoctonia alliance, but some associate with a wider diversity of fungi. These fungi may be a key factor influencing the distribution of orchids and their presence can be tested by orchid seed bait bioassays. These bioassays show that mycorrhizal fungi are concentrated in coarse organic matter that may be depleted in some habitats (e.g. by frequent fire). Mycorrhizal fungi also allow efficient propagation of terrestrial orchids for reintroduction into natural habitats and for bioassays to test habitat quality. Four categories of WA orchids are defined by the following pollination strategies: (i) nectar-producing flowers with diverse pollinators, (ii) non-rewarding flowers that mimic other plants, (iii) winter-flowering orchids that attract fungus-feeding insects and (iv) sexually deceptive orchids with relatively specific pollinators. An exceptionally high proportion of WA orchids have specific insect pollinators. Bioassays testing orchid-pollinator specificity can define habitats and separate closely related species. Other research has revealed the chemical basis for insect attraction to orchids and the ecological consequences of deceptive pollination. Genetic studies have revealed that the structure of orchid populations is influenced by pollination, seed dispersal, reproductive isolation and hybridisation. Long-term demographic studies determine the viability of orchid populations, estimate rates of transition between seedling, flowering, non-flowering and dormant states and reveal factors, such as grazing and competition, that result in declining populations. It is difficult to define potential new habitats for rare orchids because of their specific relationships with fungi and insects. An understanding of all three dimensions of orchid habitat requirements can be provided by bioassays with seed baits for fungi, flowers for insects and transplanted seedlings for orchid demography. The majority of both rare and common WA orchids have highly specific associations with pollinating insects and mycorrhizal fungi, suggesting that evolution has favoured increasing specificity in these relationships in the ancient landscapes of WA.

scholarly journals Conservation-driven Propagation of an Epiphytic Orchid (Epidendrum nocturnum) with a Mycorrhizal Fungus

HortScience ◽  
2007 ◽  
Vol 42 (1) ◽  
pp. 135-139 ◽  
Author(s):  
Lawrence W. Zettler ◽  
Sarah B. Poulter ◽  
Kris I. McDonald ◽  
Scott L. Stewart
Keyword(s):  
Mycorrhizal Fungus ◽  
Leaf Length ◽  
Ex Vitro ◽  
Commercial Fertilizer ◽  
Epiphytic Orchid ◽  
Seed Sources ◽  
Terrestrial Orchids ◽  
Half Strength ◽  
Symbiotic Seed Germination

Seeds of an endangered epiphytic orchid from Florida (Epidendrum nocturnum Jacquin) germinated in vitro with a mycorrhizal fungus [Epulorhiza repens (Bernard) Moore] using a technique normally applied to terrestrial orchids (symbiotic seed germination). Seeds from two sources (Fakahatchee Strand, Fla. Panther NWR) were sown on either modified oats medium (MOM) or standard oat medium (SOM) and inoculated with the fungus. Significant differences in germination were detected between the two seed sources. MOM had a significant effect on mean leaf length during incubation in vitro (F (1278) = 23.81, P > 0.000), but media had no significant effect on leaf number. After 48 days in vitro, all leaf-bearing seedlings were exposed to light and then transferred to greenhouse conditions ex vitro on sterile Sphagnum moss with or without half-strength Miracle-Gro (Scotts, Port Washington, N.Y.) commercial fertilizer. After 163 days ex vitro, seedlings on Sphagnum without Miracle-Gro displayed highest survivorship (>90%), whereas Miracle-Gro-exposed seedlings from standard oat agar experienced low (44%) survivorship. Healthy seedlings with a mycotrophic capability were obtained 1 year after sowing. A total of 43 seedlings were subsequently reintroduced into the Florida Panther NWR in Nov. 2005, 16 months after sowing. The symbiotic technique may, therefore, have practical merit for conservation of E. nocturnum and other epiphytic orchids threatened with extinction.

scholarly journals Evaluación de un sistema para la micorrización in vitro en plantas de mora de castilla (Rubus glaucus, Benth)

2012 ◽  
Vol 17 (2) ◽  
pp. 140 ◽  
Author(s):  
Urley Adrian Pérez-Moncada ◽  
María Margarita Ramírez-Gómez ◽  
Víctor Manuel Núñez-Zarante ◽  
Marcela Franco-Correa ◽  
Gabriel Roveda-Hoyos
Keyword(s):  
Mycorrhizal Fungi ◽  
Culture System ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Dry Weight ◽  
Extraradical Mycelium ◽  
Direct Inoculation ◽  
Autotrophic Culture ◽  
Glomus Sp

<strong>Objective</strong>. Obtain an in vitro mycorrhization system in autotrophic culture systems of blackberry plants (Rubus glaucus, Benth). <strong>Materials and methods</strong>. We used spores and root fragments with vesicles of Arbuscular Mycorrhizal Fungus (AMF) Glomus sp (GEV02). We established an autotrophic culture system of blackberry plantlets comparing two methods of direct inoculation of the AMF. We measured the number of spores produced, the length of the extraradical mycelium as well as the percentage of colonization of the AMF. Additionally, we measured the shoot and root length, and the fresh and dry weight of the leaf and root parts to determine the plant development. <strong>Results</strong>. The autotrophic culture system was successful for blackberry plants (Rubus glaucus, Benth; an optimal shoot and root growth was observed. Additionally, we obtained a system that allowed the development of Glomus sp. in in vitro conditions, with the formation of structures typical of the symbiosis as well as a good intraradical colonization, with the production of arbuscules and vesicles, development of extraradical mycelium with branched hyphae, and formation of new spores. <strong>Conclusion</strong>. For the first time, micropropagated blackberry plants associated successfully with an AMF under in vitro conditions, enabling the development of the symbiotic system AMF Glomus sp. associated to roots of micropropagated blackberry plantlets.<br /><strong>Key words</strong>: arbuscular mycorrhizal fungi (AMF), autotrophic culture, Rubus glaucus Benth, Glomus sp. (GEV02), in vitro mycorrhization.

scholarly journals Utilization of exogenous saccharides by protocorms of two terrestrial orchids  

2017 ◽  
Vol 63 (No. 4) ◽  
pp. 152-158
Author(s):  
Ponert Jan ◽  
Lipavská Helena
Keyword(s):  
Mycorrhizal Fungi ◽  
Life Strategy ◽  
Limited Knowledge ◽  
Phylogenetic Relations ◽  
Wide Range ◽  
Terrestrial Orchids ◽  
Time Utilization ◽  
First Time ◽  
Germination Stage

Orchid protocorms are completely mycoheterotrophic structures. Although saccharides are proposed as the main energy and carbon (C) sources provided by fungi, there is only limited knowledge on their effects. For the first time, utilization of a wide range of saccharides by in vitro axenic protocorms of two terrestrial orchids from two subfamilies, Ophrys iricolor subsp. lojaconoi and Oeceoclades, was tested. Protocorm size and, in the first of these also rhizoid length and soluble saccharide contents, were analysed. The endogenous saccharide spectra reflected the supplied saccharides and their metabolism. In both species, sucrose supported protocorm growth best. Surprisingly, fructose inhibited O. iricolor subsp. lojaconoi protocorm growth while O. decaryana ones grew well on it. Interestingly, mannitol abundant in mycorrhizal fungi was not utilized while sorbitol not found in fungi was usable. Galactose was toxic at pre-germination stage. Protocorm rhizoid length correlated with protocorm size but revealed several signalling effects of some saccharides. In conclusion, the orchid’s ability to utilize various saccharides reflects more likely species life strategy rather than phylogenetic relations or saccharide abundance in mycorrhizal fungi.  

scholarly journals Propagation and reintroduction of Caladenia

2009 ◽  
Vol 57 (4) ◽  
pp. 373 ◽  
Author(s):  
Magali Wright ◽  
Rob Cross ◽  
Kingsley Dixon ◽  
Tien Huynh ◽  
Ann Lawrie ◽  
...  
Keyword(s):  
Conservation Planning ◽  
Mycorrhizal Fungi ◽  
Ex Situ ◽  
Terrestrial Orchid ◽  
Natural Habitats ◽  
Nurse Plants ◽  
Mycorrhizal Associations ◽  
Symbiotic Germination ◽  
Growing Conditions

Many Caladenia species have been reduced to extremely small and/or fragmented populations, and reintroduction/translocation into natural or rehabilitated habitats, by using ex situ propagated plants or via direct seeding, represents an important adjunct in conservation planning. However, Caladenia species are some of the most difficult terrestrial orchid taxa to propagate, in part because of the specificity of the mycorrhizal associations and the need to provide growing conditions that suit both the mycorrhizal fungi and Caladenia plants. The present paper reviews recent advances in Caladenia propagation and reintroduction methods, including in vitro seed germination, transferral from in vitro to nursery environments, ex vitro symbiotic germination (germination in inoculated nursery media), nursery cultivation, the use of nurse plants and reintroduction of Caladenia into natural habitats by using seed, dormant tubers or growing plants. Techniques discussed in the present paper increase the options for future Caladenia conservation programs, especially for those species currently on the brink of extinction.

Food preferences of a fungal-feeding Aphelenchoides species

Nematology ◽  
2000 ◽  
Vol 2 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Liliane Ruess ◽  
Erick J. Garcia Zapata ◽  
John Dighton
Keyword(s):  
Mycorrhizal Fungi ◽  
Food Source ◽  
Food Preferences ◽  
Fungal Species ◽  
Fungal Host ◽  
Toxic Metabolites ◽  
Mycorrhizal Associations ◽  
Marked Preference ◽  
Choice Chamber

Abstract The growth of Aphelenchoides sp. populations was investigated in vitro with 17 different fungal species as food source. Nematode mass cultures were obtained with saprophytic (Agrocybe, Chaetomium) and especially with mycorrhizal fungi (Cenococcum, Hymenoscyphus, Laccaria). Mitosporic species, like Alternaria, Monocillium or Penicillium, were generally meagre or non-hosts. This poor host suitability is likely due to the release of toxic metabolites (e.g. antibiotics) and/or to morphological differences (e.g., forming of conidiophores) by the fungi. Frequent grazing of nematodes on mycorrhizal mycelia may be of major significance for the establishment and maintenance of mycorrhizal associations in the field. Food preference of Aphelenchoides sp. was tested in choice chamber experiments. Nematodes showed a marked preference for particular fungal species. They changed food source with time, indicating a “mixed diet” selection, probably a strategy to avoid the concentration of toxic metabolites. The attractiveness of a fungus was not necessarily correlated with its suitability as a host. That a poor fungal host can be a strong nematode attractant and influence their spatial distribution in the soil has implications for nematode populations in the field. In Laborexperimenten wurde die Vermehrung des Nematoden Aphelenchoides sp. mit 17 verschiedenen Pilzspezies als Nahrungsgrundlage untersucht. Neben saprophytischen Arten (Agrocybe, Chaetomium) eigneten sich insbesondere Mykorrhizapilze (Cenococcum, Hymenoscyphus, Laccaria) für eine Massenvermehrung. Eine schlechte Nahrungsquelle stellten mitosporische Arten, wie Alternaria, Monocillium oder Penicillium, dar. Dies dürfte auf toxische Stoffwechselprodukte (z.B., Antibiotika) und/oder auf morphologische Unterschiede (z.B., Sporenbildung) zurückzuführen sein. Die gute Vermehrung der Nematoden an Mykorrhizapilzen ist von weitreichender Bedeutung für das Freiland. Negative Auswirkungen auf die Ausbildung und Funktion von Mykorrhiza im Boden sind zu erwarten. In Nahrungswahlexperimenten zeigte Aphelenchoides sp. eine ausgeprägte Präferenz für bestimmte Pilzarten. Das Wechseln zwischen den einzelnen Pilzspezies weist auf die Bevorzugung von “Mischnahrung” hin. Dies dürfte eine Strategie zur Vermeidung von hohen Konzentrationen toxischer Nahrungsbestandteile sein. Präferenz und Nahrungsqualität standen nur in geringem Zusammenhang. Somit können auch Pilze, die eine schlechte Nahrungsquelle darstellen, attraktiv auf Nematoden wirken und deren Verbreitung in Boden und Rhizosphäre beeinflussen.

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