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Orbiliaceae

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A fungus of the genus Arthrobotrys, showing adhesive nets that it uses to trap nematodes. Numbered ticks are 122 μm apart.

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.[1] Members of this family have a widespread distribution, but are more prevalent in temperate regions.[2] Some species in the Orbiliaceae are carnivorous fungi, and have evolved a number of specialized mechanisms to trap nematodes.

Description

Orbiliaceae do not have stromata, dense structural tissue that produces fruit bodies. They have small disc-shaped apothecia, that are typically convex, brightly colored or translucent.[2] Their ascospores are small (typically less than 10 x 1 μm), hyaline, and have an oval or ellipsoidal shape.[3] Species are usually found in wood on both wet and dry habitats.[2] Anamorph species are hyphomycetous.[4]

Nematophagy

This family is well known for its many nematophagous species.[5] Shortly after coming into contact with its prey, fungal mycelia penetrate the nematode and spontaneously differentiate into functional structures, known as traps, which will ultimately digest the nematode's internal contents.[6] There are 5 types of trap mechanisms recognized in this family:[6][7][8][9]

  • Adhesive network: the most common trap, formed by hyphal outgrowths that recurve into themselves to form nematode-trapping loops.
  • Adhesive knob: a roughly spherical cell, attached to the hyphae either directly or on an erect stalk. Adhesive knobs are typically closely spaced along a section of hyphae.
  • Nonconstricting rings: always found with the adhesive network traps, and formed from thickening hyphae that curve and fuse to the supporting stalk.
  • Adhesive column: a layer of cells on a hyphae with an adhesive surface.
  • Constricting rings: these are rings of hyphae that swell rapidly inwards upon contact with the nematode, quickly (in 1–2 seconds) "lassoing" the victim.

Genera

According to the most recent classification of Ascomycota,[10] the Orbiliaceae contain only two (teleomorph) genera, the Hyalorbilia and the Orbilia. Hyalorbilia is distinguished from Orbilia by having asci without a stalk that arise from croziers, a hemispherical to broadly conical, thin-walled apex, asci and paraphyses in a gelatinous matrix, and an ectal excipulum (the outer surface of a cup-like apothecium) of horizontal textura prismatica.[11][12]

Anamorph genera of the Orbiliaceae include Anguillospora,[13] Arthrobotrys,[14] Dactylella,[15] Dactylellina, Dicranidion,[16] Drechslerella, Helicoön,[17] Monacrosporium, and Trinacrium. It has been suggested that the anamorph specialization illustrates convergent evolution occurring among mycelial fungi in aquatic and low-nitrogen habitats.[18] This hypothesis has been borne out by recent phylogenetic and morphological studies.[19]

In 2007, a new species was described from southwestern China with morphological features intermediate between Orbilia and Hyalorbilia. This species, named Pseudorbilia bipolaris Y. Zhang, Z.F. Yu, H.O. Baral & K.Q. Zhang, was placed into its own genus in the Orbiliaceae to accommodate its distinctive features.[20]

References

  1. ^ Kirk, Paul M.; Cannon, Paul F.; Minter, David W.; Stalpers, Joost A., eds. (2008). "Orbiliaceae". Ainsworth & Bisby's Dictionary of the Fungi. CABI. p. 485. ISBN 978-0-85199-826-8.
  2. ^ a b c Cannon, P. F.; Kirk, P. M., eds. (2007). "Orbiliaceae". Fungal Families of the World. CABI. pp. 251–252. ISBN 978-0-85199-827-5.
  3. ^ Blackwell M, Alexopoulos CJ, Mims CW (1996). Introductory Mycology. New York: Wiley. ISBN 0-471-52229-5.
  4. ^ Bisby GR, Ainsworth GC, Kirk PM, Aptroot A (2001). Ainsworth & Bisby's Dictionary of the Fungi. Oxon: CAB International. p. 369. ISBN 0-85199-377-X.
  5. ^ Pfister, Donald H. (1997). "Castor, Pollux and life histories of fungi". Mycologia. 89 (1): 1–23. doi:10.1080/00275514.1997.12026750.
  6. ^ a b Barron, George L. (1977). The Nematode-destroying Fungi. Guelph: Canadian Biological Publications. ISBN 0-920370-00-4.
  7. ^ Yang, Ying; Yang, Ence; An, Zhiqiang; Liu, Xingzhong (15 May 2007). "Evolution of nematode-trapping cells of predatory fungi of the Orbiliaceae based on evidence from rRNA-encoding DNA and multiprotein sequences". Proceedings of the National Academy of Sciences of the United States of America. 104 (20): 8379–8384. Bibcode:2007PNAS..104.8379Y. doi:10.1073/pnas.0702770104. PMC 1895958. PMID 17494736.
  8. ^ Drechsler, Charles (1 July 1937). "Some Hyphomycetes that Prey on Free-Living Terricolous Nematodes". Mycologia. 29 (4): 447–552. doi:10.1080/00275514.1937.12017222.
  9. ^ Stirling GR (1991). Biological control of plant parasitic nematodes. Wallingford, UK: C.A.B. International. ISBN 0-85198-703-6.
  10. ^ "Outline of Ascomycota - 2007". Retrieved 2008-12-25.
  11. ^ Baral, HO (1994). "Comments on 'Outline of the ascomycetes-1993'". Systema Ascomycetum. 13 (1): 113–128. NAID 10014785631.
  12. ^ Wu, Mei-Lee; Su, Yu-Chih; Baral, Hans-Otto; Liang, Shih-Hsiung (2007). "Two new species of Hyalorbilia from Taiwan" (PDF). Fungal Diversity. 25: 233–244. CiteSeerX 10.1.1.594.3347. S2CID 90409824.
  13. ^ Webster, J; Descals, E. (1979). "The teleomorphs of water-borne Hyphomycetes from fresh water". In Kendrick, Bryce (ed.). The Whole Fungus: The Sexual-asexual Synthesis. National Museum of Natural Sciences. pp. 419–451. ISBN 978-0-660-00146-3.
  14. ^ Pfister, Donald H. (1 May 1994). "Orbilia fimicola, a nematophagous discomycete and its Arthrobotrys anamorph". Mycologia. 86 (3): 451–453. doi:10.1080/00275514.1994.12026433.
  15. ^ Thakur, S.; Zachariah, K. (1 November 1989). "Response of the fungus Dactylella rhopalota to bacteria". Plant and Soil. 120 (1): 87–93. doi:10.1007/BF02370294. S2CID 28858277.
  16. ^ Korf, Richard P (1992). "A preliminary discomycete flora of Macaronesia: Part 8, Orbiliaceae". Mycotaxon. 45: 503–510. INIST:4551685.
  17. ^ Pfister, DH (1995). "Helicoon sessile, the anamorph of Orbilia luteorubella". Inoculum. Mycological Society of America. 46: 34.
  18. ^ Webster, John (June 2011). "Convergent evolution and the functional significance of spore shape in aquatic and semi-aquatic fungi". In Rayner, A. D. M.; Brasier, C. M.; Moore, David (eds.). Evolutionary Biology of the Fungi: Symposium of The British Mycological Society Held at the University of Bristol April 1986. Cambridge University Press. pp. 191–201. ISBN 978-0-521-27925-3. NAID 10019290922.
  19. ^ Li Y, Hyde KD, Jeewon R, Cai L, Vijaykrishna D, Zhang K (2005). "Phylogenetics and evolution of nematode-trapping fungi (Orbiliales) estimated from nuclear and protein coding genes". Mycologia. 97 (5): 1034–46. doi:10.3852/mycologia.97.5.1034. hdl:10722/53351. PMID 16596955.
  20. ^ Zhang, Ying; Yu, Ze-Fen; Baral, H.-O.; Qiao, Min; Zhang, Ke-Qin (2007). "Pseudorbilia gen. nov. (Orbiliaceae) from Yunnan, China" (PDF). Fungal Diversity. 26: 305–312.

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Orbiliaceae: Brief Summary

provided by wikipedia EN
 src= A fungus of the genus Arthrobotrys, showing adhesive nets that it uses to trap nematodes. Numbered ticks are 122 μm apart.

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.

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cc-by-sa-3.0
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