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Myco-heterotrophy (Greek: μυκός mykós, "fungus", ἕτερος heteros = "another", "different" and τροφή trophe = "nutrition") is a symbiotic relationship between certain kinds of plants and fungi, in which the plant gets all or part of its food from parasitism upon fungi rather than from photosynthesis. A myco-heterotroph is the parasitic plant partner in this relationship. Myco-heterotrophy is considered a kind of cheating relationship and myco-heterotrophs are sometimes informally referred to as "mycorrhizal cheaters". This relationship is sometimes referred to as mycotrophy, though this term is also used for plants that engage in mutualistic mycorrhizal relationships. == Relationship between myco-heterotrophs and host fungi == Full (or obligate) myco-heterotrophy exists when a non-photosynthetic plant (a plant largely lacking in chlorophyll or otherwise lacking a functional photosystem) gets all of its food from the fungi that it parasitizes. Partial (or facultative) myco-heterotrophy exists when a plant is capable of photosynthesis, but parasitizes fungi as a supplementary food supply. There are also plants, such as some orchid species, that are non-photosynthetic and obligately myco-heterotrophic for part of their life cycle, and photosynthetic and facultatively myco-heterotrophic or non-myco-heterotrophic for the rest of their life cycle.〔Leake JR. 1994. (The biology of myco-heterotrophic ('saprophytic') plants. ) ''New Phytologist'' 127: 171–216. . ''Warning: large document''〕 Not all non-photosynthetic or "achlorophyllous" plants are myco-heterotrophic – some non-photosynthetic plants like dodder directly parasitize the vascular tissue of other plants.〔Dawson JH, Musselman LJ, Wolswinkel P, Dörr I. 1994. Biology and control of ''Cuscuta''. ''Reviews of Weed Science'' 6: 265–317.〕 In the past, non-photosynthetic plants were mistakenly thought to get food by breaking down organic matter in a manner similar to saprotrophic fungi. Such plants were therefore called "saprophytes". It is now known that no plant is physiologically capable of direct breakdown of organic matter and that in order to get food, non-photosynthetic plants must engage in parasitism, either through myco-heterotrophy or direct parasitism of other plants.〔Bidartondo MI. 2005. (The evolutionary ecology of myco-heterotrophy. ) ''New Phytologist'' 167: 335–352. PMID 15998389.〕〔Leake JR. 2005. (Plants parasitic on fungi: unearthing the fungi in myco-heterotrophs and debunking the ‘saprophytic’ plant myth ). ''Mycologist'' 19: 113–122. .〕 The interface between the plant and fungal partners in this association is between the roots of the plant and the mycelium of the fungus. Myco-heterotrophy therefore closely resembles mycorrhiza (and indeed is thought to have evolved from mycorrhiza),〔 except that in myco-heterotrophy, the flow of carbon is from the fungus to the plant, rather than vice versa.〔Trudell SA, Rygiewicz PT, Edmonds RL. 2003. (Nitrogen and carbon stable isotope abundances support the myco-heterotrophic nature and host-specificity of certain achlorophyllous plants. ) ''New Phytologist'' 160: 391–401. .〕〔Bidartondo MI, Burghardt B, Gebauer G, Bruns TD, Read DJ. 2004. (Changing partners in the dark: isotopic and molecular evidence of ectomycorrhizal liaisons between forest orchids and trees. ) ''Proceedings of the Royal Society of London'', series B 271: 1799–1806. .〕 Most myco-heterotrophs can therefore be seen as ultimately being epiparasites, since they take energy from fungi that in turn get their energy from vascular plants.〔〔〔Selosse M-A, Weiss M, Jany J, Tilier A. 2002. (Communities and populations of sebacinoid basidiomycetes associated with the achlorophyllous orchid ''Neottia nidus-avis'' (L.) L.C.M. Rich. and neighbouring tree ectomycorrhizae ). ''Molecular Ecology'' 11: 1831–1844. .〕 Indeed, much myco-heterotrophy takes place in the context of common mycorrhizal networks, in which plants use mycorrhizal fungi to exchange carbon and nutrients with other plants.〔 In these systems, myco-heterotrophs play the role of "mycorrhizal cheaters", taking carbon from the common network, with no known reward.〔 In congruence with older reports, it has been recently shown that some myco-heterotrophic orchids can be supported by saprotrophic fungi, exploiting litter- or wood-decaying fungi.〔Martos F, Dulormne M, Pailler T, Bonfante P, Faccio A, Fournel J, Dubois M-P, Selosse M-A. 2009. (Independent recruitment of saprotrophic fungi as mycorrhizal partners by tropical achlorophyllous orchids ). ''New Phytologist'' 184: 668–681. .〕 In addition, several green plants (evolutionarily close to myco-heterotrophic species) have been shown to engage in partial myco-heterotrophy, that is, they are able to take carbon from mycorrhizal fungi, in addition to their photosynthetic intake.〔Gebauer G, Meyer M. 2003. (15N and 13C natural abundance of autotrophic and myco-heterotrophic orchids provides insights into nitrogen and carbon gain from fungal association ). ''New Phytologist'' 160: 209–223. .〕〔Selosse M-A, Roy M. 2009. Green plants eating fungi: facts and questions about mixotrophy. ''Trends in Plant Sciences'' 14: 64–70. PMID 19162524.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Myco-heterotrophy」の詳細全文を読む スポンサード リンク
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