Neotyphodium coenophialum
Encyclopedia
Neotyphodium coenophialum is a systemic and seed-transmissible symbiont (endophyte) of Schedonorus arundinaceus (=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, principally ergovaline produced by N. coenophialum.
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 produces two classes of alkaloids, loline alkaloids
and the pyrrolopyrazine, peramine, which are insecticidal and insect deterrent, respectively, and presence of the fungus increases drought tolerance, nitrogen utilization, phosphate acquisition, and resistance to nematodes. 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, and also provide some, but not necessarily all, of the benefits attributable to the "common toxic" strains in the older tall fescue cultivars.
Molecular phylogenetic analysis indicates that N. coenophialum is an interspecific hybrid with three ancestors: Epichloë
festucae, Epichloë
typhina and an undescribed or extinct Neotyphodium
species that also contributed a genome to the hybrid endophyte Neotyphodium occultans, among others.
Festuca arundinacea
Festuca arundinacea is a species of fescue commonly known as Tall fescue. It is a cool-season perennial C3 species of bunchgrass native to Europe. It is an important forage grass throughout Europe, and many cultivars have been used in agriculture...
), 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
Fescue
Festuce is a genus of about 300 species of perennial tufted grasses, belonging to the grass family Poaceae . The genus has a cosmopolitan distribution, although the majority of the species are found in cool temperate areas...
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
Ergotism
Ergotism is the effect of long-term ergot poisoning, traditionally due to the ingestion of the alkaloids produced by the Claviceps purpurea fungus which infects rye and other cereals, and more recently by the action of a number of ergoline-based drugs. It is also known as ergotoxicosis, ergot...
in humans, the most likely agents responsible for fescue
Fescue
Festuce is a genus of about 300 species of perennial tufted grasses, belonging to the grass family Poaceae . The genus has a cosmopolitan distribution, although the majority of the species are found in cool temperate areas...
toxicosis are thought to be the ergot alkaloids, principally ergovaline produced by N. coenophialum.
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 produces two classes of alkaloids, loline alkaloids
Loline alkaloids
A loline alkaloid is a member of the 1-aminopyrrolizidines , which are bioactive natural products with several distinct biological and chemical features...
and the pyrrolopyrazine, peramine, which are insecticidal and insect deterrent, respectively, and presence of the fungus increases drought tolerance, nitrogen utilization, phosphate acquisition, and resistance to nematodes. 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, and also provide some, but not necessarily all, of the benefits attributable to the "common toxic" strains in the older tall fescue cultivars.
Molecular phylogenetic analysis indicates that N. coenophialum is an interspecific hybrid with three ancestors: Epichloë
Epichloë
Epichloë species and their close relatives, the Neotyphodium species, are systemic and constitutive symbionts of cool-season grasses , and belong to the fungal family Clavicipitaceae...
festucae, Epichloë
Epichloë
Epichloë species and their close relatives, the Neotyphodium species, are systemic and constitutive symbionts of cool-season grasses , and belong to the fungal family Clavicipitaceae...
typhina and an undescribed or extinct Neotyphodium
Neotyphodium
Neotyphodium is a form genus containing species of endophytic fungi. These endophytes are asexual, seed-borne symbionts of cool-season grasses, and grow intercellularly throughout the aerial tissues of their hosts, including shoot apical meristems, leaf sheaths and blades, inflorescences, seeds and...
species that also contributed a genome to the hybrid endophyte Neotyphodium occultans, among others.