“…Although the disease was reported many years ago in Oregon (Shaw and Muth, 1949;Galloway, 19611, it has not been observed recently because of the widespread use of open field burning to dispose of grass straw and stubble. Although annual ryegrass is the main grass involved, recent reports from Australia (Finnie, 1991; implicate several other grasses, including blowngrass ( Agrostis avenacea) and annual beardgrass (Polypogon monspeliensis) . The disorders associated with these grasses are locally known as floodplain staggers (blowngrass) and Stewarts Range Syndrome (beardgrass).…”
Plant toxins are the chemical defenses of plants against herbivory. Grasses have relatively few intrinsic toxins, relying more on growth habit to survive defoliation and endophytic fungal toxins as chemical defenses. Forage grasses that contain intrinsic toxins include Phalaris spp. (tryptamine and carboline alkaloids), sorghums (cyanogenic glycosides), and tropical grasses containing oxalates and saponins. Toxic effects of these grasses include neurological damage (Phalaris staggers), hypoxia (sudangrass), saponin-induced photosensitization (Brachiaria and Panicum spp.), and bone demineralization (oxalate-containing grasses). Endophytic toxins in grasses include ergot alkaloids in tall fescue and tremorgens (e.g., lolitrem B) in perennial ryegrass. Lolitrems cause neurological effects, producing the ryegrass staggers syndrome. Annual ryegrass toxicosis is caused by corynetoxins, which are chemically similar to tunicamycin antibiotics. Corynetoxins are produced by Clavibacter bacteria that parasitize a nematode, Anguina agrostis, that may infect annual ryegrass. Corynetoxins inhibit glycoprotein synthesis, causing defective formation of various blood components of the reticulo-endothelial system. Another mycotoxin in ryegrass is sporidesmin, which causes liver damage and secondary photosensitization (facial eczema). Fusarium toxins such as zearalenone and trichothecenes also occur in forage grasses. Kikuyugrass poisoning results in severe damage to the ruminal epithelium and omasal mucosa, and neurological signs. The causative agent, which may be associated with army worm predation of the grass, has not been identified. The properties and significance of these toxins are reviewed.
“…Although the disease was reported many years ago in Oregon (Shaw and Muth, 1949;Galloway, 19611, it has not been observed recently because of the widespread use of open field burning to dispose of grass straw and stubble. Although annual ryegrass is the main grass involved, recent reports from Australia (Finnie, 1991; implicate several other grasses, including blowngrass ( Agrostis avenacea) and annual beardgrass (Polypogon monspeliensis) . The disorders associated with these grasses are locally known as floodplain staggers (blowngrass) and Stewarts Range Syndrome (beardgrass).…”
Plant toxins are the chemical defenses of plants against herbivory. Grasses have relatively few intrinsic toxins, relying more on growth habit to survive defoliation and endophytic fungal toxins as chemical defenses. Forage grasses that contain intrinsic toxins include Phalaris spp. (tryptamine and carboline alkaloids), sorghums (cyanogenic glycosides), and tropical grasses containing oxalates and saponins. Toxic effects of these grasses include neurological damage (Phalaris staggers), hypoxia (sudangrass), saponin-induced photosensitization (Brachiaria and Panicum spp.), and bone demineralization (oxalate-containing grasses). Endophytic toxins in grasses include ergot alkaloids in tall fescue and tremorgens (e.g., lolitrem B) in perennial ryegrass. Lolitrems cause neurological effects, producing the ryegrass staggers syndrome. Annual ryegrass toxicosis is caused by corynetoxins, which are chemically similar to tunicamycin antibiotics. Corynetoxins are produced by Clavibacter bacteria that parasitize a nematode, Anguina agrostis, that may infect annual ryegrass. Corynetoxins inhibit glycoprotein synthesis, causing defective formation of various blood components of the reticulo-endothelial system. Another mycotoxin in ryegrass is sporidesmin, which causes liver damage and secondary photosensitization (facial eczema). Fusarium toxins such as zearalenone and trichothecenes also occur in forage grasses. Kikuyugrass poisoning results in severe damage to the ruminal epithelium and omasal mucosa, and neurological signs. The causative agent, which may be associated with army worm predation of the grass, has not been identified. The properties and significance of these toxins are reviewed.
“…C orynetoxins are highly toxic chemicals produced by the bacterium Clavibacter toxicus, which infects developing seed heads of certain pasture grasses resulting in serious episodes of poisoning in grazing livestock. The principal corynetoxicoses in Australia are ARGT, flood plain staggers and Stewart Ranges syndrome, caused by C toxicus infection of annual ryegrass (Lolium rigidum), 1,2 blown grass (Agrostis avenacea) [3][4][5] and annual beardgrass (Polypogon monspeliensis), 6 respectively. The most important economic problem is ARGT, which has caused major outbreaks with high mortality and leads to major changes in the physical and biochemical properties of the 'guest' molecule.…”
Protection studies using these two beta-cyclodextrin derivatives suggest that they may be effective in increasing the survival of sheep poisoned by tunicamycin and warrant further testing in field outbreaks of annual ryegrass toxicity.
“…This pasture association has led to the common designation of the disease as Annual Ryegrass Toxicity or ARGT. 1 In 1991, in Australia, R. toxicus was also found to be responsible for a severe neurologic disorder with high mortality in sheep and cattle grazing annual beard grass ( Polypogon monspeliensis ) in flood-prone areas of the south-east of South Australia, 14,15 and blown grass ( Agrostis avenacea ) on the floodplains of northern New South Wales. 15,16 Annual ryegrass is not a prominent pasture species in either of these regions.…”
Section: Geographic Distribution Of Corynetoxicitymentioning
confidence: 99%
“…1 While Anguina funesta prefers annual ryegrass ( Lolium rigidum ), a pasture plant introduced to Australia in 1880, it can also parasitize other grasses, such as annual beard grass ( Polypogon monspeliensis ) and blown grass ( Agrostis avenacea ). 14,16 Figure 1. Anguina sp. larvae in a nematode gall of annual ryegrass ( Lolium rigidum ).…”
Section: The Nematode-bacterium Complex Required For Corynetoxin Pois...mentioning
Corynetoxins, members of the tunicamycin group of antibiotics, are produced by the bacterium, Rathayibacter toxicus. They cause a severe neurologic disorder in domestic livestock, are hepatotoxins, and can damage retinal photoreceptors. For these toxins to be ingested by livestock, the bacterium must first be transported onto host plants by adhering to nematode larvae. In the infected seed heads, bacterial galls (gumma) then form. While corynetoxicity occurs most commonly in Australia, it has occurred sporadically in other countries and, due to the widespread global distribution of the bacterium, nematode, and host plants, there is great potential for further spread, particularly as the range of host plant species and nematode vectors identified for R. toxicus is increasing. Since many animal species are susceptible to corynetoxins poisoning, it is likely that humans would also be vulnerable if exposed to these potent, lethal toxins.
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