Dactylellina haptotyla

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Dactylellina haptotyla
Scientific classification
Kingdom:
Fungi
Division:
Ascomycota
Subdivision:
Pezizomycotina
Class:
Orbiliomycetes
Order:
Orbiliales
Family:
Orbiliaceae
Genus:
Dactylellina
Species:
D. haptotyla
Binomial name
Dactylellina haptotyla
(Drechsler) M. Scholler, Hagedorn & A. Rubner (1999)
Synonyms
  • Arthrobotrys haptotylaDrechsler (1977)
  • Golovinia haptotyla(Drechsler) Mekht (1967)
  • Candelabrella haptotyla(Drechsler) Rifai (1968)
  • Dactylella haptotyla(Drechsler) de Hoog & Oorschot (1985)
  • Monacrosporium haptotylum(Drechsler) Xing Z. Liu & K.Q. Zhang (1994)
  • Dactylium candidum Nees (1817)
  • Dactylaria sclerohyphaDrechsler (1950)
  • Golovinia capitulopagaMekht. (1979)
  • Monacrosporium yunnanenseK.Q. Zhang, Xing Z. Liu & L. Cao (1996)
  • Dactylellina candidum(Nees) Yan Li (2006)

Dactylellina haptotyla is a common soil-living fungus that develops structures to capture nematodes as nutrient source. In the presence of nematodes, spores can germinate into sticky knobs or non-constricting loops. [1] The fungus traps nematodes with sticky knobs and non-constricting loops, then breakdown the cuticle, and penetrates the body of nematodes to obtain nutrients. For its predatory nature, Dactylellina haptotyla is also considered as nematode-trapping fungus or carnivorous fungus.

Contents

Taxonomy

Dactylellina haptotyla belongs to the family Orbiliaceae. Before nematode-trapping fungi were studied phylogenetically, Dactylellina haptotyla had been classified with more than five synonyms, and it is commonly known as Arthrobotrys candida, Monacrosporium haptotyla and Dactylella haptotyla. The classification was ambiguous because the fungus does not form non-constricting loops all the time. For example, M. candidum and M.yunnanense form stalk adhesive knobs and non-constricting rings, while M. sclerohypha and M.haptotylum only form adhesive knobs. [2] Yet, these four species are all synonyms of Dactylellina haptotyla.

In 1999, the carnivorous fungi of Orbiliaceae has been reclassified based on rDNA and β-tubulin datasets. [3] Nematode-trapping fungi can be grouped into four monophyletic clade ( Arhtrobotrys , Monacrosporium , Dactylella and Dactylellina ) which correspond to their nematode-trapping structures. Therefore, Dactylellina haptotyla has been classified as genus Dactylellina because of its non-constricting loops and sticky knobs structure.

Growth and morphology

Dactylellina haptotyla can be isolated on corn meal agar. After fifteen days of incubation, the colour of colonies changes from hyaline (unpigmented) to whitish or faintly pink colour. [4] Colony diameter can expand by 4 cm at 25 °C within 10 days.

Conidiophores are hyaline branches that are constructed by 5-7 septate. It is about 100–335μm long, 2–3.7 μm wide at the base. 2-12 (mostly 3-5) branches can grow near apex with conidia. [4] Macroconidia are also hyaline and in spindle-shape (truncate at the base and narrow down at the basal end). It is usually constructed by 2-5 septate, and approximately 27.5–57.5 × 7.5–12.5μm2 (mostly 35 × 9μm2) in size. No chlamydospores have been observed in cultures.

The spindle spores can develop into adhesive knob in the presence of nematodes. [1] The adhesive knob is a globose adhesive cell locates at the end of non-adhesive stalk which is composed by one to three cells. The adhesive knob contains membrane-bound vesicles which is approximately 0.2-0.5μm. [5] The other trapping structure, non-constricting loop, is constructed by three cells which elongate from stalk and fuse back to base. The inner area of the loop is sticky.

Nematode-trapping features

Dactyllelina haptotyla traps nematodes by adhesive knobs and non-constricting loops.

When nematodes thrust into non-constricting loops or adhesive knobs, the trapping structures wedge the nematodes by the sticky surface. [1] Nematodes struggle and sometimes become more tightly wedged because they contact other loops or knobs. In some cases, the struggle may be so violent that the nematode can escape and detach the knobs or loops from stalks. The detached knobs or loops stay on the nematode's body and travel along. Eventually, the fungus will paralyze and digest the nematode. Evolutionary, this assist the Dactylellina haptotyla to migrate to new sites and explore food sources.

The adhesive knob contains membrane-bound vesicles, 0.2-0.5μm in diameter, with various electron densities. [5] The electron-dense vesicles are rarely seen in stalk cells' cytoplasm. When sticky knob adheres a nematode, electron-dense vesicles migrate toward nematode and discard the enzymatic contents to degrade the cuticle. The sub-cuticle swells [1] and infection bulbs permeate the body. [5] The infection bulb is separated from the sticky knob with septum. It can take about 36 hours to degrade a nematode, and a new trap will form afterward. [6]

Linoleic acid, has been identified in the mycelial extracts. [4] It is an aliphatic compound that is antibacterial and nematocidal.

Although the nematode-attractant has not been identified, a common hypothesis is the nematode-trapping fungus are able to release pheromones to attract nematodes. [1]

Genomics

The total genome size of Dactylellina haptotyla is estimated as 40.4Mb with 271 genes/Mb and 3.3 exons/gene. [7]

Based on a cDNA microarray study, [7] 23.3% of the studied gene pool are differentially expressed in mycelium and knobs. Some of those genes are responsible for cell polarity regulation. For example, profilin and cofilin are downregulated in knobs. Moreover, the transcription pattern of sticky knobs shows similarities with appressoria of plant pathogenic fungi like Magnaporthe grisea and Blumeria graminis . Particularly, peptide sequences of some defense and stress response protein are significantly similar.

When Caenorhabditis elegans adheres, the transcriptional pattern changes significantly as well. The initial transcriptional responses begin after one hour of attachment. [8] Approximately 40% of nematodes were paralyzed after four hours, and 372 gene clusters are upregulated only during this stage of infection. Among the 372 gene clusters, 79% of genes are specific to Dactylellina haptotyla or other closely related species.

On the other hand, 26 CFEM-containing proteins and 28 GLEYA-containing proteins are identified as adhesive molecules on knobs and loops. CFEM-containing proteins function as adhesion molecules or cell-surface receptors. GLEYA-containing proteins bind to lectin-like ligand domain. [9]

APES protein with unknown function was also identified in Dactylellina haptotyla. [10]

Habitat and ecology

Dactylellina haptotyla is distributed in soil worldwide. [4]

In 1998, Jaffee, Ferris and Scow [11] compared the population of nematode-trapping fungi in conventional and organic systems. A conventional system was soil plots that were fertilized by inorganic matters and grown with cover crop every four year. The organic system was soil plots that were treated with manure and grown with cover crop every year. Different nematode-trapping fungi prefers different systems. Dactylellina haptotyla is more populated in conventional plots. Yet, the cause of impact in population was unclear. Also, number of the fungus increased when water content was higher in soil. In general, nematode-trapping fungi prefer to colonize on cellulose and lignin substrates with low nitrogen content. [12]

Industrial use

The use of Dactylellina haptotyla as bio-control agent in agricultural industry has been explored. However, the application has not been proven yet.

Related Research Articles

<span class="mw-page-title-main">Hypha</span> Long, filamentous structure in fungi and Actinobacteria

A hypha is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium.

<i>Glomus</i> (fungus) Genus of arbuscular mycorrhizal fungi

Glomus is a genus of arbuscular mycorrhizal (AM) fungi, and all species form symbiotic relationships (mycorrhizae) with plant roots. Glomus is the largest genus of AM fungi, with ca. 85 species described, but is currently defined as non-monophyletic.

<span class="mw-page-title-main">Carnivorous fungus</span> Fungus which traps and eats tiny animals

Carnivorous fungi or predaceous fungi are fungi that derive some or most of their nutrients from trapping and eating microscopic or other minute animals. More than 200 species have been described, belonging to the phyla Ascomycota, Mucoromycotina, and Basidiomycota. They usually live in soil and many species trap or stun nematodes, while others attack amoebae or collembola.

This is a glossary of some of the terms used in phytopathology.

Dactylella is a genus comprising 72 species of mitosporic fungi in the family Orbiliaceae. They are notable for trapping and eating nematodes.

Hyphomycetes are a form classification of fungi, part of what has often been referred to as fungi imperfecti, Deuteromycota, or anamorphic fungi. Hyphomycetes lack closed fruit bodies, and are often referred to as moulds. Most hyphomycetes are now assigned to the Ascomycota, on the basis of genetic connections made by life-cycle studies or by phylogenetic analysis of DNA sequences; many remain unassigned phylogenetically.

Clonostachys rosea f. rosea, also known as Gliocladium roseum, is a species of fungus in the family Bionectriaceae. It colonizes living plants as an endophyte, digests material in soil as a saprophyte and is also known as a parasite of other fungi and of nematodes. It produces a wide range of volatile organic compounds which are toxic to organisms including other fungi, bacteria, and insects, and is of interest as a biological pest control agent.

Acremonium strictum is an environmentally widespread saprotroph species found in soil, plant debris, and rotting mushrooms. Isolates have been collected in North and Central America, Asia, Europe and Egypt. A. strictum is an agent of hyalohyphomycosis and has been identified as an increasingly frequent human pathogen in immunosuppressed individuals, causing localized, disseminated and invasive infections. Although extremely rare, A. strictum can infect immunocompetent individuals, as well as neonates. Due to the growing number of infections caused by A. strictum in the past few years, the need for new medical techniques in the identification of the fungus as well as for the treatment of human infections has risen considerably.

<span class="mw-page-title-main">Nematophagous fungus</span> Carnivorous fungi specialized in trapping and digesting nematodes

Nematophagous fungi are carnivorous fungi specialized in trapping and digesting nematodes. Around 160 species are known. Species exist that live inside the nematodes from the beginning and others that catch them, mostly with glue traps or in rings, some of which constrict on contact. Some species possess both types of traps. Another technique is to stun the nematodes using toxins, a method employed by Coprinus comatus, Stropharia rugosoannulata, and the family Pleurotaceae. The habit of feeding on nematodes has arisen many times among fungi, as is demonstrated by the fact that nematophagous species are found in all major fungal groups. Nematophagous fungi can be useful in controlling those nematodes that eat crops. Purpureocillium, for example, can be used as a bio-nematicide.

<span class="mw-page-title-main">Nematode</span> Phylum of worms with tubular digestive systems with openings at both ends

The nematodes, roundworms or eelworms constitute the phylum Nematoda. They are a diverse animal phylum inhabiting a broad range of environments. Most species are free-living, feeding on microorganisms, but there are many that are parasitic. The parasitic worms (helminths) are the cause of soil-transmitted helminthiases.

<span class="mw-page-title-main">Orbiliaceae</span> Family of fungi

The Orbiliaceae are a family of saprobic sac fungi in the order Orbiliales. The family, first described by John Axel Nannfeldt in 1932, contains 288 species in 12 genera. Members of this family have a widespread distribution, but are more prevalent in temperate regions. Some species in the Orbiliaceae are carnivorous fungi, and have evolved a number of specialized mechanisms to trap nematodes.

<i>Purpureocillium lilacinum</i> Species of fungus

Purpureocillium lilacinum is a species of filamentous fungus in the family Ophiocordycipitaceae. It has been isolated from a wide range of habitats, including cultivated and uncultivated soils, forests, grassland, deserts, estuarine sediments and sewage sludge, and insects. It has also been found in nematode eggs, and occasionally from females of root-knot and cyst nematodes. In addition, it has frequently been detected in the rhizosphere of many crops. The species can grow at a wide range of temperatures – from 8 to 38 °C for a few isolates, with optimal growth in the range 26 to 30 °C. It also has a wide pH tolerance and can grow on a variety of substrates. P. lilacinum has shown promising results for use as a biocontrol agent to control the growth of destructive root-knot nematodes.

<i>Rhopalomyces elegans</i> Species of fungus

Rhopalomyces elegans is a common species of zygomycete fungus, and the type species of the genus Rhopalomyces. Widely distributed, it is found in soil, rotting plant material, and animal dung. It is a facultative parasite of nematode eggs.

<i>Harposporium anguillulae</i> Species of fungus

Harposporium anguillulae is a member of the genus Harposporium. It is an endoparasitic nematophagous fungus that attacks nematodes and eelworms and is isolated commonly from field and agricultural soils as well as used as an experimental organism in the laboratory.

<i>Arthrobotrys oligospora</i> Species of fungus

Arthrobotrys oligospora was discovered in Europe in 1850 by Georg Fresenius. A. oligospora is the model organism for interactions between fungi and nematodes. It is the most common nematode-capturing fungus, and most widespread nematode-trapping fungus in nature. It was the first species of fungi documented to actively capture nematodes.

Arthrobotrys dactyloides is a species of fungus in the family Orbiliaceae. It is nematophagous, forming loops of hypha to trap nematodes, on which it then feeds.

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Birgit Ann-Marie Margareta Nordbring-Hertz, was a Swedish scientist at Lund University known for her work on the interactions between fungi and nematodes.

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References

  1. 1 2 3 4 5 Barron, G.L. (1977). The nematode-destroying fungi. Guelph: Canadian Biological Publications. ISBN   978-0920370001.
  2. ↑ Li, Yan; Hyde, Kevin D.; Jeewon, Rajesh; Cai, Lei; Vijaykrishna, Dhanasekaran; Zhang, Keqin (1 September 2005). "Phylogenetics and evolution of nematode-trapping fungi (Orbiliales) estimated from nuclear and protein coding genes". Mycologia. 97 (5): 1034–1046. doi:10.3852/mycologia.97.5.1034. hdl: 10722/53351 . ISSN   0027-5514. PMID   16596955.
  3. ↑ Scholler, Markus; Hagedorn, Gregor; Rubner, A. (1999). "A reevaluation of predatory orbiliaceous fungi.II. A new generic concept". Sydowia. 51 (1): 89–113.
  4. 1 2 3 4 Ke-Qin Zhang; Kevin D. Hyde, eds. (2014). Nematode-trapping fungi (Aufl. 2014 ed.). Dordrecht: Springer Netherlands. ISBN   9789401787307.
  5. 1 2 3 Saikawa, Masatoshi; Kaneko, Makoto (April 1994). "Electron microscopy of infection of nematodes by Dactylaria haptotyla". Mycoscience. 35 (1): 89–94. doi:10.1007/BF02268534. S2CID   84235224.
  6. ↑ Meerupati, Tejashwari; Andersson, Karl-Magnus; Friman, Eva; Kumar, Dharmendra; Tunlid, Anders; Ahrén, Dag; Richardson, Paul M. (14 November 2013). "Genomic Mechanisms Accounting for the Adaptation to Parasitism in Nematode-Trapping Fungi". PLOS Genetics. 9 (11): e1003909. doi: 10.1371/journal.pgen.1003909 . PMC   3828140 . PMID   24244185.
  7. 1 2 Ahren, D. (1 March 2005). "Comparison of gene expression in trap cells and vegetative hyphae of the nematophagous fungus Monacrosporium haptotylum". Microbiology. 151 (3): 789–803. doi: 10.1099/mic.0.27485-0 . PMID   15758225. S2CID   9191426.
  8. ↑ Fekete, Csaba; Tholander, Margareta; Rajashekar, Balaji; Ahrén, Dag; Friman, Eva; Johansson, Tomas; Tunlid, Anders (February 2008). "Paralysis of nematodes: shifts in the transcriptome of the nematode-trapping fungus Monacrosporium haptotylum during infection of Caenorhabditis elegans". Environmental Microbiology. 10 (2): 364–375. doi:10.1111/j.1462-2920.2007.01457.x. PMID   18028414.
  9. ↑ Li, Juan; Zou, Chenggang; Xu, Jianping; Ji, Xinglai; Niu, Xuemei; Yang, Jinkui; Huang, Xiaowei; Zhang, Ke-Qin (4 August 2015). "Molecular Mechanisms of Nematode-Nematophagous Microbe Interactions: Basis for Biological Control of Plant-Parasitic Nematodes". Annual Review of Phytopathology. 53 (1): 67–95. doi: 10.1146/annurev-phyto-080614-120336 . PMID   25938277.
  10. ↑ Zhao, Yong; Su, Hao; Zhou, Jing; Feng, Huihua; Zhang, Ke-Qin; Yang, Jinkui (August 2015). "The APSES family proteins in fungi: Characterizations, evolution and functions". Fungal Genetics and Biology. 81: 271–280. doi:10.1016/j.fgb.2014.12.003. PMID   25534868.
  11. ↑ Jaffee, B. A.; Ferris, H.; Scow, K. M. (April 1998). "Nematode-Trapping Fungi in Organic and Conventional Cropping Systems". Phytopathology. 88 (4): 344–350. doi: 10.1094/PHYTO.1998.88.4.344 . PMID   18944958.
  12. ↑ Blackwell, C.J. Alexopoulos ; C.W. Mims ; M. (1996). Introductory mycology (4. ed.). New York [u.a.]: Wiley. ISBN   9780471522294.{{cite book}}: CS1 maint: multiple names: authors list (link)
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