Epichloë coenophiala: Difference between revisions
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'''''[[Neotyphodium]] coenophialum''''' is a systemic and seed-transmissible [[symbiont]] (endophyte) of ''Lolium arundinaceum'' (='Festuca arundinacea'; tall [[fescue]]), a grass endemic to Eurasia and North Africa, but widely naturalized in North America, Australia and New Zealand / Aotearoa. The endophyte has been identified as the cause of the "[[fescue]] toxicosis" syndrome sometimes suffered by livestock that graze the ''N. coenophialum''-infected grass. Possible symptoms include poor weight gain, elevated body temperature, reduced conception rates, agalactia, rough hair coat, fat necrosis, loss of switch and ear tips, and lameness or dry gangrene of the feet. Because of the resemblance to symptoms of [[ergotism]] in humans, the most likely agents responsible for [[fescue]] toxicosis are thought to be the ergot alkaloids produced by ''N. coenophialum''. <ref name="Lyons1986">{{cite journal|author=Lyons PC, Plattner RD, Bacon CW|year=1986|title=Occurrence of peptide and clavine ergot alkaloids in tall fescue grass|journal=Science|volume=232|pages=487-489}}</ref> |
'''''[[Neotyphodium]] coenophialum''''' is a systemic and seed-transmissible [[symbiont]] (endophyte) of ''Lolium arundinaceum'' (='Festuca arundinacea'; tall [[fescue]]), a grass endemic to Eurasia and North Africa, but widely naturalized in North America, Australia and New Zealand / Aotearoa. The endophyte has been identified as the cause of the "[[fescue]] toxicosis" syndrome sometimes suffered by livestock that graze the ''N. coenophialum''-infected grass. Possible symptoms include poor weight gain, elevated body temperature, reduced conception rates, agalactia, rough hair coat, fat necrosis, loss of switch and ear tips, and lameness or dry gangrene of the feet. Because of the resemblance to symptoms of [[ergotism]] in humans, the most likely agents responsible for [[fescue]] toxicosis are thought to be the ergot alkaloids produced by ''N. coenophialum''. <ref name="Lyons1986">{{cite journal|author=Lyons PC, Plattner RD, Bacon CW|year=1986|title=Occurrence of peptide and clavine ergot alkaloids in tall fescue grass|journal=Science|volume=232|pages=487-489}}</ref> |
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Continued popularity of tall fescue with this endophyte, despite episodic livestock toxicosis, is attributable to the exceptional productivity and stress tolerance of the grass in pastures and hay fields. The endophyte enhances several of these characteristics, including drought tolerance, nitrogen utilization, phosphate acquisition, and resistance to nematodes.<ref name="Malinowski2000">{{cite journal|author=Malinowski DP, Belesky DP|year=2000|title=Adaptations of endophyte-infected cool-season grasses to environmental stresses: Mechanisms of drought and mineral stress tolerance|journal=Crop Sci|volume=40|pages=923-940}}</ref><ref name="Timper2005">{{cite journal|author=Timper P, Gates RN, Bouton JH|year=2005|title=Response of ''Pratylenchus'' spp. in tall fescue infected with different strains of the fungal endophyte ''Neotyphodium coenophialum''|journal=Nematology|volume=7|pages=105-110}}</ref> Recently, natural strains of ''N. coenophialum'' with little or no ergot alkaloid production have been introduced into tall fescue for new cultivar development. These strains are apparently not toxic to livestock,<ref name="Parish2003">{{cite journal|author=Parish JA, McCann MA, Watson RH, Paiva NN, Hoveland CS, Parks AH, Upchurch BL, Hill NS, Bouton JH|year=2003|title=Use of nonergot alkaloid-producing endophytes for alleviating tall fescue toxicosis in stocker cattle|journal=J Animal Sci|volume=81|pages=2856-2868}}</ref> and also provide some, but not necessarily all, of the benefits attributable to the "common toxic" strains in the older tall fescue cultivars. <ref name="Parish2003"/><ref name="Timper2005"/> |
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Molecular [[phylogenetic]] analysis indicates that ''N. coenophialum'' is an interspecific hybrid with three ancestors<ref name="Tsai">{{cite journal|author=Tsai HF, Liu JS, Staben C, Christensen MJ, Latch GC, Siegel MR, Schardl CL|year= 1994|title=Evolutionary diversification of fungal endophytes of tall fescue grass by hybridization with <i>Epichloë</i> species|journal= Proc. Natl. Acad. Sci. USA|volume=91|pages= 2542-2546|id=PMID 8172623}}</ref>: ''[[Epichloë]] festucae'', ''[[Epichloë]] typhina'' and an undescribed or extinct ''[[Neotyphodium]]'' species that also contributed a genome to the hybrid endophyte ''[[Neotyphodium occultans]]'', among others. |
Molecular [[phylogenetic]] analysis indicates that ''N. coenophialum'' is an interspecific hybrid with three ancestors<ref name="Tsai">{{cite journal|author=Tsai HF, Liu JS, Staben C, Christensen MJ, Latch GC, Siegel MR, Schardl CL|year= 1994|title=Evolutionary diversification of fungal endophytes of tall fescue grass by hybridization with <i>Epichloë</i> species|journal= Proc. Natl. Acad. Sci. USA|volume=91|pages= 2542-2546|id=PMID 8172623}}</ref>: ''[[Epichloë]] festucae'', ''[[Epichloë]] typhina'' and an undescribed or extinct ''[[Neotyphodium]]'' species that also contributed a genome to the hybrid endophyte ''[[Neotyphodium occultans]]'', among others. |
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Revision as of 07:12, 9 April 2007
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Neotyphodium coenophialum is a systemic and seed-transmissible symbiont (endophyte) of Lolium arundinaceum (='Festuca arundinacea'; tall fescue), a grass endemic to Eurasia and North Africa, but widely naturalized in North America, Australia and New Zealand / Aotearoa. The endophyte has been identified as the cause of the "fescue toxicosis" syndrome sometimes suffered by livestock that graze the N. coenophialum-infected grass. Possible symptoms include poor weight gain, elevated body temperature, reduced conception rates, agalactia, rough hair coat, fat necrosis, loss of switch and ear tips, and lameness or dry gangrene of the feet. Because of the resemblance to symptoms of ergotism in humans, the most likely agents responsible for fescue toxicosis are thought to be the ergot alkaloids produced by N. coenophialum. [1]
Continued popularity of tall fescue with this endophyte, despite episodic livestock toxicosis, is attributable to the exceptional productivity and stress tolerance of the grass in pastures and hay fields. The endophyte enhances several of these characteristics, including drought tolerance, nitrogen utilization, phosphate acquisition, and resistance to nematodes.[2][3] Recently, natural strains of N. coenophialum with little or no ergot alkaloid production have been introduced into tall fescue for new cultivar development. These strains are apparently not toxic to livestock,[4] and also provide some, but not necessarily all, of the benefits attributable to the "common toxic" strains in the older tall fescue cultivars. [4][3]
Molecular phylogenetic analysis indicates that N. coenophialum is an interspecific hybrid with three ancestors[5]: Epichloë festucae, Epichloë typhina and an undescribed or extinct Neotyphodium species that also contributed a genome to the hybrid endophyte Neotyphodium occultans, among others.
References
- ^ Lyons PC, Plattner RD, Bacon CW (1986). "Occurrence of peptide and clavine ergot alkaloids in tall fescue grass". Science. 232: 487–489.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Malinowski DP, Belesky DP (2000). "Adaptations of endophyte-infected cool-season grasses to environmental stresses: Mechanisms of drought and mineral stress tolerance". Crop Sci. 40: 923–940.
- ^ a b Timper P, Gates RN, Bouton JH (2005). "Response of Pratylenchus spp. in tall fescue infected with different strains of the fungal endophyte Neotyphodium coenophialum". Nematology. 7: 105–110.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ a b Parish JA, McCann MA, Watson RH, Paiva NN, Hoveland CS, Parks AH, Upchurch BL, Hill NS, Bouton JH (2003). "Use of nonergot alkaloid-producing endophytes for alleviating tall fescue toxicosis in stocker cattle". J Animal Sci. 81: 2856–2868.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Tsai HF, Liu JS, Staben C, Christensen MJ, Latch GC, Siegel MR, Schardl CL (1994). "Evolutionary diversification of fungal endophytes of tall fescue grass by hybridization with Epichloë species". Proc. Natl. Acad. Sci. USA. 91: 2542–2546. PMID 8172623.
{{cite journal}}: CS1 maint: multiple names: authors list (link)