Epiparasitism

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Epiparasitism is the indirect exploitation of one living being by another through the mediation of a third party.

History and content of the term

The term was coined in 1960 by the Swedish forest botanist Erik Björkman for the relationship between the myco-heterotrophic spruce asparagus ( Monotropa hypopitys ) and the surrounding forest trees, mediated by mycorrhizal fungi : The seeds of Monotropa hypopitys only germinate after fungal infection by knightly species ( Tricholoma ). But even the adult plants are still dependent on the supply of carbohydrates from the fungus, which the fungus in turn obtains from its mycorrhizal partners, the forest trees. The autotrophic trees are parasitized by heterotrophic spruce asparagus with the help of a fungal bridge.

Since the 1990s, the term has been used more comprehensively for myco-heterotrophic plants than the previously used, factually incorrect term " saprophyte " came under criticism.

The biologist Martin Bidartondo defined the term as a “three-part symbiosis of a parasitic partner, an intermediary partner and a final host partner” ( tripartite symbiosis between a parasitic lineage, an intermediate host lineage and an ultimate host lineage ).

Recently, however, this use of the term has also been criticized as being incorrect because it implies that the fungus acts exclusively as a “nutrient bridge”, but otherwise remains unaffected. However, all mykoheterotrophic plants, as far as examined, kill the hyphae growing into the root tissue and then digest them using enzymes . For these destructive "epiparasites", among other things, the term "exploitative mycorrhiza" has been suggested.

The epiparasitic way of life differs fundamentally from hyperparasitism ; however, the terms are often confused or used synonymously.

Examples of epiparasitic plants

Apart from the heather plants without chlorophyll , the epiparasitic way of life occurs mainly in myco-heterotrophic orchids. Examples from the Central European flora are the bird's nest root ( Neottia nidus-avis ), the coral root ( Corallorhiza trifida ) and the violet thing ( Limodorum abortivum ). Other epiparasitic orchids include Gastrodia minor and Rhizanthella gardneri , an Australian orchid. The mycorrhizal fungus Thanatephorus gardneri, which has grown together with its roots, is also a symbiotic partner of the myrtle heather Melaleuca uncinata . The fungus receives nutrients from the tree and passes some of them on to the orchid.

But even for a liverwort , the underground Cryptothallus mirabilis , it could be shown that it is epiparasitic.

See also

Parasitism , mycotrophy , mycorrhiza

literature

  • Ulrich Kull: Ecology: Epiparasitism - a parasitism in a roundabout way . In: Naturwissenschaftliche Rundschau 56 (2003), p. 157, ISSN  0028-1050 .

Web links

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  1. ↑ Erik Björkman: Monotropa hypopitys L., an epiparasite on tree roots. In: Physiologia plantarum 13 (1960), pp. 308-327.
  2. ↑ JR Leake, SL McKendrick, MI Bitardondo, DJ Read: Symbiotic germination and development of the myco-heterotroph Monotropa hypopitys in nature and its requirement for locally distributed Tricholoma spp. In: New Phytologist 163 (2004), pp. 405-423.
  3. ↑ Leake, JR: Myco-heterotroph / epiparasitic plant interactions with ectomycorrhizal and arbuscular mycorrhizal fungi . In: Current Opinion in Plant Biology 7 (2004), pp. 422-428.
  4. ↑ Jonathan R. Leake: The biology of myco-heterotrophic ('saprophytic') plants. In: Tansley Review No. 69, New Phytologist 127: pp. 171-216, 1994
  5. ↑ Jonathan R. Leake: Myco-heterotroph / epiparasitic plant interactions with ectomycorrhizal and arbuscular mycorrhizal fungi. In: Current Opinion in Plant Biology 7, pp. 422-428, 2004
  6. ↑ Jonathan R. Leake: Plants parasitic on fungi: unearthing the fungi in myco-heterotrophs and debunking the 'saprophytic' plant myth. In: Mycologist 19, pp. 113-122, 2005
  7. ↑ Martin Bidartondo: Tansley Review: The evolutionary ecology of myco-hetero trophy. In: New Phytologist 167, p. 352, 2005
  8. ↑ M. Brundrett: Diversity and classification of mycorrhizal associations. In: Biol. Rev. Camb. Philos. Soc. ; 79 (3), pp. 473-495, 2004
  9. ↑ McKendrick, SL, Leake, JR, Taylor, DL & DJ Read: Symbiotic germination and development of myco-heterotrophic Neottia nidus-avis in nature and its requirement for locally distributed Sebacina spp . In: New Phytologist 154 (2002), pp. 233-247.
  10. ↑ McKendrick, SL, Leake, JR & DJ Read: Symbiotic germination and development of myco-heterotrophic plants in nature: transfer of carbon from ectomycorrhizal Salix repens and Betula pendula to the orchid Corallorhiza trifida through shared hyphal connections . In: New Phytologist 145 (2000), pp. 539-548.
  11. ↑ Girlanda, M., Selosse, MA, Cafasso, D., Brilli, F., Delfine, S., Fabbian, R., Ghignone, S., Pinelli, P., Segrete, R., Loreto, F., Cozzolino, S. & S. Perotto: Inefficient photosynthesis in the Mediterranean orchid Limodorum abortivum is mirrored by specific association to ectomycorrhizal Russulaceae . In: Molecular Ecology 15 (2006), pp. 491-504.
  12. ↑ Ella O. Campbell: Gastrodia minor Petrie, an epiparasite of manuka. In: Transactions of the Royal Society of New Zealand (Botany) 2 (1963), pp. 73-81.
  13. ↑ Martin I. Bidartondo, Thomas D. Bruns, Michael White, Cecília Sérgio and David J. Read: Specialized cheating of the ectomycorrhizal symbiosis by at epiparasitic liverwort . In: Proceedings of the Royal Society London , Series B 270 (2003), pp. 835-842