Showing papers on "Neotyphodium published in 1997"

Protective Grass Endophytes: Where are they from and where are they going?

Abstract: erhaps the most widely used agents of biological plant protection are endophytic fungal symbionts (endophytes) of forage and turfgrasses. These are fungi of the family Clavicipitaceae, which grow between host cells in vegetative tissues, ovules, and seeds of systemically infected grass plants. The existence of these endophytes was not fully appreciated until recent years, although the protection they provide against insect damage (Fig. 1) and drought contributes to the superior agronomic qualities of favorite pasture grasses in North America, Australia, and New Zealand. Unfortunately for livestock farmers, these endophytes also provide a degree of protection from grazing mammals. In 1977, Bacon et al. (2) reported that the grass Festuca arundinacea var. genuina Schreb. (hexaploid tall fescue) had a fungal endophyte related to Epichloe typhina (Pers.:Fr.) Tul., and that this endophyte— now known as Neotyphodium coenophialum (Morgan-Jones & Gams) Glenn, Bacon, & Hanlin—was responsible for toxicosis suffered by livestock grazing the grass. Epichloe species were known for many decades (44), but reports relating that nonpathogenic endophytes could be detrimental to livestock provided new impetus for intensive studies, making the grass–endophyte associations among the best characterized symbioses in biology. Less than two decades of research have yielded a rich body of knowledge about these symbioses: their secondary product chemistry, ecology, evolution, genetics, and molecular biology; their ecological roles as protectants from insect and vertebrate herbivores, pathogenic fungi and nematodes, and drought; and their effects on host growth and competitiveness. The endophytes produce numerous alkaloids, some of which are unrelated to any known from plants or other fungi. Their genetic and evolutionary complexity is extraordinary. They were the first fungi genetically documented as interspecific hybrids (47,53). Meanwhile, molecular genetic techniques were applied to the endophytes of tall fescue and other grasses, bringing us closer to the prospect of reducing or eliminating their toxicosis to livestock while continuing to employ their bioprotective qualities.

Neotyphodium/grass interactions

Abstract: An Overview of Neotyphodium-Grass Interactions G.C.M. Latch. Evolution and Systematics of Grass-Endophyte Associations: The Evolution of Mutualism in Grass-Endophyte Associations H.H. Wilkinson, C.L. Schardl. Systematics of the Graminicolous Clavicipitacea: Applications of Morphological and Molecular Approaches J.F. White. Ecological Interactions of Endophyte-Grass Associations: Ecological Diversity in Neotyphodium-Infected Grasses as Influenced by Host and Fungus Characteristics A. Leuchtmann. Consequences of Endophyt-Infected Grasses on Plant K. Clay. Soil Invertebrate Species Diversity and Abundance in Endophyte-Infected Tall Fescue Pastures E.C. Bernard, et al. Commercial Uses of Endophyte-Infected Grasses: The Evaluation and Use of Endophytes for Pasture Improvement L.R. Fletcher, H.S. Easton. Use of Natural and Transformed Endophytes for Turf Improvement C.R. Funk, J.F. White. Animal Toxicoses: Fescue Toxicosis in Horses D.L. Cross. Physiological Manifestations of Endophyte Toxicosis in Ruminant and Laboratory Species J.W. Oliver. 6 Additional Chapters. Short Papers. Index.

Growth and Water Status in Meadow Fescue is Affected by Neotyphodium and Phialophora Species Endophytes

Abstract: Growth and water status in meadow fescue (Festuca elatior L.; syn. F. pratensis Huds.) is affected by Neotyphodium and Phialophora endophytes. Meadow fescue is often infected with Neotyphodium uncinatum (Gams, Petrini & Schmidt) Glenn, Bacon, Price & Hanlin or cosymbiotically with this and a Phialophora-like endophyte. In a growth chamber experiment, we determined the influence of these endophytes on selected growth attributes and plant water status of one genotype of meadow fescue. Single plants of done M1 free of endophytes (E-) or infected with N. uncinatum (N), Phialophora-like endophyte (P), or both endophytes (NP) were adequately irrigated (control plants) or subjected to a gradually established soil water deficit for 26 d (stressed plants). Afterwards, stressed plants were rewatered and allowed to regrow for 4 wk. Cumulative herbage dry matter (DM) yield was greater in P plants by 7.5% compared with N plants, generally. Control P plants produced more root DM than E- and NP plants. Root DM in N plants was significantly greater during recovery from drought, compared with P and NP plants (36%). Tiller number of NP plants was the lowest among endophyte treatments in the predrought period. In response to water stress, P plants produced more tillers than E- plants (24%), but average tiller weight of P plants was lower than in E- plants (14%). During imposed water stress, stomatal conductance (g s ) and leaf water potential (ψ L ) decreased in all plant-endophyte associations to a similar extent. At severe soil water deficit, however, N plants had significantly lower g s and ψ L than the other plant-endophyte associations. Control plants benefited from the symbiosis with endophytes by increasing root growth (both endophytes) and shoot growth (Phialophora-like endophyte). Plants infected with N. uncinatum were potentially able to adjust to soil water depletion earlier, suggesting a greater potential for adaptation to drought.

The effect of imperfect transmission on the frequency of mutualistic seed-borne endophytes in natural populations of grasses

Abstract: We develop a simple mathematical model to explain the lower than expected levels of infection of wild perennial ryegrass populations in France by endophytic Neotyphodium fungi (formerly named Acremonium). Indeed, seed-borne Neotyphodium endophytes are considered as mutualistic symbionts, because they increase survival, growth and flowering rates of their hosts, and should therefore be present at very high frequencies in all host populations. However, recent surveys have shown that 70% of wild populations of perennial ryegrass harbour such endophytes in France. Moreover, most infected populations exhibit a low level of infection. Our simple model, taking into account the life-cycles of the host and the fungus, shows that these patterns can be satisfactorily explained if the vertical transmission of the fungus is imperfect. Such imperfect transmission, though never measured in natural populations, is likely because of the reported mortality of the endophyte in stored seeds. This process, analogous to the mutation-selection balance of classical population genetics theory, may explain the observed patterns even better when we consider random fluctuations of selection coefficients over time and genetic drift.

Molecular systematics of Clavicipitaceae supporting monophyly of genus Epichloe and form genus Ephelis

Abstract: The family Clavicipitaceae (Ascomycota) is comprised of fungi with perithecia borne on stro- mata, unitunicate asci, and filamentous, multiseptate ascospores. All are biotrophic symbionts, either mu- tualistic with plant hosts or pathogenic to plants, in- vertebrate animals or other fungi. Genera of plant- associated Clavicipitaceae (tribes Balansieae and Clavicipieae) are distinguished, in part, by stromal and ascus morphology, ascospore germination pat- terns, whether sclerotia are formed, and host inter- actions. Their anamorphs include enteroblastic mi- croconidial states, classified in anamorphic genera Neotyphodium and Sphacelia (for teleomorphs Atkin- sonella, Claviceps, Echinodothis, and Epichloe), and ho- loblastic macroconidia, classified in the anamorphic genus Ephelis (teleomorphs Atkinsonella, Balansia, and Myriogenospora). Epichloe' species often are mu- tualistic with grass hosts, and are ancestral to asexual, seed transmitted endophytes symbiotic with many cool-season grasses. Partial 28S nuclear rDNA se- quences were determined from isolates of five species and two undescribed mating populations of Epichloe, one asexual Epichloe hybrid (Neotyphodium coeno- phialum), and representatives of six other genera in the family. Results from phylogenetic analysis of the sequences supported monophyly of plant-associated Clavicipitaceae, with insect-pathogenic Cordyceps spe- cies more deeply rooted. Four clades were distin-

Distribution and Accumulation of the Alkaloid Peramine in Neotyphodium lolii-Infected Perennial Ryegrass

Abstract: Through the production of alkaloids and mycotoxins, the endophytic fungus of perennial ryegrass, Neotyphodium lolii, confers resistance to the host grass against several insect pasture pests and causes health problems in livestock. The effects of plant component, plant reproductive development, and plant management (trimming) on the concentration and accumulation of peramine, the alkaloid thought to be most important for conferring resistance against Argentine stem weevil, were investigated. Clones of eight different naturally occurring perennial ryegrass-N. lolii associations were used in the experiment, which was conducted during spring–summer, which corresponded with the height of plant reproductive activity. Clones were either trimmed regularly to maintain them in a vegetative state (V clones) or not trimmed, allowing them to become fully reproductive (R clones). V and R clones of each grass/endophyte association were destructively harvested at times that corresponded roughly with the start, middle, and end of the plant reproductive phase. Harvested material was dissected into a number of plant components that were analyzed for peramine concentration by HPLC. All clippings from the V clones were also analyzed. Peramine concentrations were usually similar in leaf sheaths and leaf blades, but they decreased as leaf age increased. The seed from R clones and younger sheaths and blades of leaves from vegetative tillers contained the highest concentrations, while the root, crown, and dead leaf tissue contained the lowest. During the inflorescence phase, tissues from reproductive tillers generally contained lower concentrations than corresponding tissues from vegetative tillers. Also at this time, mean peramine concentrations were higher in V clones than in R clones. By the end of the plant reproductive phase, at the mature seed stage, mean peramine concentrations in R and V clones were similar. The seed component, which contained approximately 75% of the total peramine present in the plant (at a mean concentration of 63.7 μg/g), probably accounted for much of the recovery in the R clones.

Modification and uses of endophyte-enhanced turfgrasses: a role for molecular technology

Abstract: Over the past decade, the significance of symbiotic fungal endophytes in turfgrasses was established as having the potential for supplementing the genetics of turfgrass improvement since endophyte-infected grasses frequently show enhanced performance. Endophyte-enhanced traits include insect and mammalian deterrence to herbivory, and often increased tolerance of drought and other abiotic stresses. However, not all endophytes are suited for use in enhancing grass performance, and only those fungi that are symptomless endophytes of grasses are currently being used. The endophytes that are of the major focus for current use include species of Neotyphodium (=Acremonium), e.g., N. coenophialum, N. lolii, and other species of Neotyphodium. The Neotyphodium endophytes do not reproduce sexually, and only produce conidia under laboratory culture, suggesting that they should be genetically stable. These endophytes can be removed from the host, transformed by molecular technology, and reinserted into the host. However, these fungi have other means for genetic variation, which might include chromosome polymorphisms, altered chromosome structures, and loss of nonessential chromosomes. Thus, the genetics related to an endophyte-enhanced trait of that turfgrass might not be stable. However, the potential for genetic engineering of the endophytes is growing nearer with recent application of DNA mediated techniques. Furthermore, genetic engineering or other approaches may soon lead to endophyte-grass associations that have further enhanced fitness or are more benign to wildlife. Before such genetically modified systems are marketed, particular attention and extensive field tests should be applied to ensure that they retain their beneficial characteristics and have truly acquired their intended improvements. Continued research into the biochemical and genetics basis of endophyte-enhanced traits should eventually identify genes that ultimately can be use for the production of transgenic grasses.

Effect of Growth Conditions on Alkaloid Concentrations in Perennial Ryegrass Naturally Infected with Endophyte

Abstract: A preliminary study of the effect of water stress on alkaloid concentrations in endophyte-infected perennial ryegrass (Lolium perenne) focused on artificial infections with selected endophyte strains (Barker et al., 1993). This paper reports the results of studies of the impact of environmental factors (nitrogen, water, temperature) on the concentration of alkaloids in “Nui” perennial ryegrass naturally infected with Neotyphodium lolii, a more typical component of New Zealand pastoral forage.

Fungal endophytes of wild barley and their effects on Diuraphis noxia population development

Abstract: Laboratory experiments were conducted to compare the expression of Diuraphis noxia (Mordvilko) (Homoptera: Aphididae) resistance in four plant introduction (PI) lines of wild barley (Hordeum) infected with different species or strains of endophytic fungi (tribe Balansieae, family Clavicipitaceae, Neotyphodium gen. nov. [formerly Acremonium]). Aphid densities were significantly lower on endophyte-infected plants of PI 314696 (H. bogdanii Wilensky) and PI 440420 (H. brevisubulatum subsp. violaceum (Boissier & Hohenacker)), compared with densities on endophyte-free plants of both PI lines in population growth experiments. This endophyte- associated resistance was the result of antibiosis effects or starvation. In other experiments, endophyte-free plants of PI 269406 and PI 440413 (H. bogdanii) were not superior to endophyte-infected conspecifics as host plants of D. noxia. Our results demonstrate the influence of host plant species/genotype and endophyte species/strain on expression of aphid resistance, provide an explanation of the high levels of D. noxia resistance in PI 314696 and PI 440420 previously reported in the literature, and underscore the potential importance of endophytic fungi in conferring insect resistance in wild barley.

Negligible Physiological Responses to Water Deficit in Endophyte-Infected and Uninfected Perennial Ryegrass

Abstract: Evidence relating improved performance of endophyte-infected perennial ryegrass during drought to plant physiological responses is equivocal. Hume et al. (1993) reported no effect of endophyte on ryegrass osmotic potential during moderate water deficit. Although evidence has shown that improved persistence of endophyte-infected tall fescue during drought is related to desirable physiological responses (West & Gwinn 1993) such evidence is sparse for ryegrass. This study aimed to compare physiological responses of “Grasslands Nui” (“Grasslands Pacific” for Exp. 2) ryegrass infected or free of “wild-type” Neotyphodium lolii endophyte, during water deficit.

An overview of neotyphodium-grass interactions

Abstract: Epichloe typhina is an endophytic fungus which causes a disease of grasses known as “choke”. In many grasses infected with this fungus the mycelium remains hidden intercellularly in the plant until flowering. Mycelium then emerges and forms a weft around the developing inflorescence preventing its development and hence no seed is produced. Some grasses such as tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne) are infected with endophytes which are related to E. typhina but have no sexual reproductive stage. The systemic mycelium of these Neotyphodium species of fungi never emerges from within the plant and these endophytes are propagated by means of seed transmission of mycelium. These latter fungi were regarded as curiosities and little notice was taken of them until their significance in agriculture was revealed two decades ago. Since then, the interactions they have with their host grasses have been studied in order to understand the remarkable relationship between the endophyte and host. With this understanding has come the realization that host and endophyte are in a mutualistic relationship. The grass provides the fungus with nutrients, shelter and a means of propagation through seed while the endophyte provides mechanisms for enhancing its host’s survival. No doubt there are many interactions in this mutualism still to be discovered but those we are presently aware of are dealt with in this overview.

Monoclonal Antibodies for Detection of Neotyphodium coenophialum

Abstract: A simple endophyte detection system is vital for breeding efforts designed to produce low alkaloid, endophyte-infected tall rescue (Festuca arundinacea Schreb.) cultivars. The objectives of this research were to generate monoclonal antibodies specific to endophytes for immunochcmical detection purposes. Protein extracts from Neotyphodium coenophialum (Morgan-Jones and Gains) Glenn, Bacon, and Hanlin comb. nov. isolate EDN11w ere injected into Balb/c mice to elicit an immuner esponse. Hybridomac ell lines were screened for antibody production to the Neotyphodium extract and for cross recognition of protein extracts from N. uncinatum Glen, Bacon, and Hanlin and N. starrii Glen, Bacon, and Hanlin, as well as other fungi in the genera Ciadosporlum, Penicilllum, Fusarium, and Aspergillus. Three hybridomace ll lines produceda ntibodies that reacted to Neotyphodium spp. proteins, but not with proteins isolated from the other fungi. Monoclonal antibody 5C7 was immunochemically tested for specificity to endophyte in leaf sheaths of plant genotype DN11. Fluorescent staining suggested the antibody preferentially bound to the cell wall of the endophyte. Antibodies were tested for affinity to protein extracts from 14 endophyte-infected and endophyte-free tall fescue genotypes by an enzyme-linked immunosorbenta ssay (ELISA) method. Mean absorbance values for the protein extracts from the endophyte-infected genotypcs differed and ranged from 0.317 to 0.583. Mean absorbance values for the endophyte-free forms did not differ (P ≥ 0.05). All infected plants had higher absorbance values than non-infected plants regardless of antibody tested. Monoclonal antibodies can be used in an ELISA to detect Neotyphodium spp. fungal mycelia present in tall fescue.

Seedborne fungal contamination: consequences in space-grown wheat

Abstract: Plants grown in microgravity are subject to many environmental stresses that may promote microbial growth and result in disease symptoms. Wheat (cv. Super Dwarf) recovered from an 8-day mission aboard a NASA (National Aeronautics and Space Administration) space shuttle showed disease symptoms, including girdling of leaf sheaths and chlorosis and necrosis of leaf and root tissues. A Neotyphodium species was isolated from the seed and leaf sheaths of symptomatic wheat used in the spaceflight mission. Certain isozymes of a peroxidase unique to extracts from the microgravity-grown plants were observed in extracts from earth-grown Neotyphodium-infected plants but were not present in noninfected wheat. The endophytic fungus was eliminated from the wheat seed by prolonged heat treatment at 50 degrees C followed by washes with water at 50 degrees C. Plants from wheat seed infected with the Neotyphodium endophyte were symptomless when grown under greenhouse conditions, whereas symptoms appeared after only 4 days of growth in closed containers. Disease spread from an infected plant to noninfected plants in closed containers. Dispersion via spores was found on asymptomatic plants at distances of 7 to 18 cm from infected plants. The size and shape of the conidia, mycelia, and phialide-bearing structures and the ability to grow rapidly on carbohydrates, especially xylose, resembled the characteristics of N. chilense, which is pathogenic on orchard grass, Doctylis glomerati. The Neotyphodium wheat isolate caused disease symptoms on other cereals (wheat cv. Malcolm, orchard grass, barley, and maize) grown in closed containers.

Distribution and Accumulation of the Mycotoxin Lolitrem B in Neotyphodium lolii - Infected Perennial Ryegrass

Abstract: The symbiotic relationship between perennial ryegrass and its endophytic fungus, Neotyphodium lolii, is of considerable agronomic significance in New Zealand. Livestock ingesting N. lolii-infected perennial ryegrass may succumb to a neuromuscular condition, ryegrass staggers, the probable cause of which has been identified as the endophyte-produced indole–diterpenoid mycotoxin lolitrem B. The effects of plant component, plant reproductive development, and plant management (clipping) on the concentration and accumulation of lolitrem B were investigated. Eight different naturally occurring perennial ryegrass–N. lolii associations were cloned. They were either trimmed regularly to maintain their vegetative state (V clones) or not trimmed at all to enable full plant reproductive development (R clones). At times that corresponded approximately with the start, middle, and end of the plant reproductive phase, V and R clones of each grass–endophyte association were destructively harvested. After dissection into a number of plant components, harvested material was analyzed for lolitrem B content by HPLC. Analyses were also performed on all clippings taken from the V clones. Highest lolitrem B concentrations in vegetative parts were found in older leaf sheaths and dead leaves. Towards the end of the plant reprodutive phase, dead leaves also contained a large proportion of the total lolitrem B content of the V clones. The highest concentration of lolitrem B was found in the seed, which accounted for nearly 60% of the total quantity in R clones. Leaf blades, young leaf sheaths, roots, and crowns generally contained low to moderate concentrations. In late spring, mean concentrations in R and V clones were similar. By the time mature seed was present (mid-summer), mean concentrations in R clones were three times higher than in V clones. This difference was attributed largely to the contribution by the seed in the R clones. The implications of these findings in relation to ryegrass staggers in livestock are discussed.

Endophytic fungi and alkaloid production in perennial ryegrass in Germany

Abstract: Infection with Neotyphodium endophyte was detected in 33 of 38 ecotype populations of Lolium perenne originating from old grassland at four widespread sites in Germany. The frequency of individual infected plants of the different populations ranged mostly from 1% to 30%; a few populations showed higher infection levels, up to 80%. The contribution of endophyte-positive plants to the biomass of the original swards was estimated to range from 1% to 34%. Concentrations of the indole alkaloid lolitrem B detected in the endophyte-positive German ecotypes were similar to those in the endophyte-positive cultivars‘Ellett’and‘Grasslands Nui', originating in New Zealand, when all were cultivated under the climatic conditions of northern Germany. A seasonal variation in lolitrem B concentrations was observed from 1993 to 1996. The highest concentrations, 0·8–1·4 mg kg−1 dry matter of herbage, were recorded during the months of July and August. These concentrations were not considered to be sufficient to induce‘ryegrass staggers', a neurological disorder in grazing animals. It is concluded that further research is necessary to elucidate the implications of grass endophytes under the climatic conditions of Central Europe.

Neotyphodium coenophialum Mycelial Protein and Herbage Mass Effects on Ergot Alkaloid Concentration in Tall Fescue

Abstract: Breeding tall fescue (Festuca arundinacea Schreb.) with low alkaloid concentration may select for tall fescue plants that are antagonistic towards Neotyphodium coenophialum (Morgan-Jones and Gams) Glenn, Bacon, and Hanlin, comb. nov. The objectives of this study were to determine the relationship between plant mass and endophyte mycelial proteins versus ergot alkaloid concentration.

Endophyte Effect on Drought Tolerance in Diverse Festuca Species

Abstract: Tall fescue (Festuca arundinacea Schreb.) drought survival is generally enhanced in high-temperature environments when infested with the fungal endophyte Neotyphodium coenophialum Glenn, Bacon, Price and Hanlin. Our group has concentrated on identifying water relations traits of the vegetative tiller base, mostly in plants from the cv. “Kentucky-31” (West, 1994). Studies on more diverse relatives of tall fescue are underway to (1) investigate whether detached-leaf conductance can serve as a screening tool for drought-stress-enhancing endophytes and (2) determine relative importance of tiller-base desiccation tolerance vs. desiccation postponement as a mode for endophyte-enhanced drought survival of the host.

Ecological diversity in neotyphodium-infected grasses as influenced by host and fungus characteristics

Abstract: Neotyphodium is the newly proposed name for the asexual state of the clavicipitaceous genus Epichloe (Glenn et al. 1996). The members of this endophytic genus form systemic, long-term associations with numerous cool season grasses (Leuchtmann 1992, White 1987). In these associations, the two partners have developed an intimate relationships over evolutionary time which in most cases can be regarded as mutualistic. The symbiosis may be more antagonistic in endophyte species which, during their sexual reproduction, profoundly affect the reproductive system of the host.

Ergovaline Distribution in Perennial Ryegrass Naturally Infected with Endophyte

Abstract: Recently there has been renewed interest in the possible impact on animal health and performance and insect resistance of ergovaline in perennial ryegrass (Lolium perenne) naturally infected with Neotyphodium lolii. In an earlier limited study of vegetative plants, ergovaline was found to be concentrated in basal tissues (Davies et al., 1993). We have now examined the ergovaline content of tissue fractions of vernalized endophyte-infected ryegrass plants in spring, and report our findings to draw attention to the effect of the reproductive status of the ryegrass plant on the exposure of grazing stock to ergovaline in the forage on offer.

Neotyphodium Coenophialum Mycelial Protein and Herbage Mass Effects on Ergot Alkaloid Concentration in Tall Fescue

Abstract: Breeding tall fescue (Festuca arundinacea Schreb.) with low alkaloid concentration may select for tall fescue plants that are antagonistic towards Neotyphodium coenophialum (Morgan-Jones and Gams) Glenn, Bacon, and Hanlin, comb. nov. The objectives of this study were to determine the relationship between plant mass and endophyte mycelial proteins versus ergot alkaloid concentration.

Soil Invertebrate Species Diversity and Abundance in Endophyte-Infected Tall Fescue Pastures

Abstract: The reduced ability of many herbivorous insects and nematodes to subsist on grasses infected by endophytic fungi is well-documented (Clay, 1989;1991). These effects upon insects are mostly due to the presence of a diverse array of alkaloids and other compounds produced by the fungus-grass symbiosis (Garner et al., 1993; Rottinghaus et al., 1991) but the mechanisms that account for nematode resistance have not yet been elucidated. Despite much research devoted to single-species herbivory on endophyte-infected grasses, little effort has yet been made to understand effects of such symbioses on soil invertebrate communities. The purpose of this review is to analyze recent progress made in the understanding of the role of the endophyte (Neotyphodium coenophialum)-tall fescue (Festuca arundinacea) symbiosis in regulation of invertebrate communities, and to suggest fruitful lines of research for the future. Because litter, fermentation, and mineral layers are a continuum and most soil arthropods move within this continuum (Eisenbeis and Wichard, 1987), “soil invertebrates” is used in the broad sense to include surface-dwelling arthropods.

Effect of selected Neotyphodium lolii isolates on root-knot nematode ( Meloidogyne marylandi ) numbers in perennial ryegrass

Abstract: Root-knot nematode numbers were assessed in roots of perennial ryegrass plants containing different strains of Neotyphodium lolii. The selected endophytes produced mycotoxin profiles differing from those found in most natural associations. Roots of endophyte-free plants contained the highest numbers of nematodes, significantly more than a perennial ryegrass/N. lolii association not producing the mammalian toxin, ergovaline. There was also a significant host plant genotype effect on nematode numbers. The results are relevant to the development of grass/endophyte associations non-toxic to livestock but resistant to nematodes.

Occurrence of endophytes in European cultivars, seed lots, and ecotypes of Festuca species

Abstract: A lot of work has been done on the occurrence and role of endophytes in ryegrass and tall fescue in the USA and New Zealand. In Europe some investigations were made on the role of endophyte infested meadow and tall fescue (BUMERL and MIKA 1991, SCHMIDT 1991), but few data are known about the occurrence of endophytes in meadow fescue. The aim was to evaluate European commercial cultivars and also ecotypes from fescue grasses for endophytic fungi.

Distribution of Ergot Alkaloids within the Family Clavicipitaceae

Abstract: In the twenty years since the first report of an ergot alkaloid-producing endophytic fungus being the causal agent of grass-associated toxicoses in livestock (Bacon et al., 1977), the production of these alkaloids are now well documented among several grass endophytes of the family Clavicipitaceae (Porter, 1994). These endophytes have been shown to convey to the host grasses certain advantageous physiological and ecological characteristics such as increased vigor, tolerance, and resistance to drought and pests (West, 1994; Rowan and Latch, 1994). Research interests have begun to focus on the potential manipulation of the fungi to retain the beneficial qualities communicated to the plant but to down-regulate or eliminate the production of toxicosis-inducing ergot alkaloids (Schardl, 1994). However, little attention has been given to the distribution of these alkaloids within the Clavicipitaceae. While select species of grass endophytes within the genera Neotyphodium, Epichloe, and Balansia have been assayed for alkaloid production, a broad sampling of the entire family is lacking, especially among the entomopathogenic species. We have undertaken such a sampling within a phylogenetic construct and have assayed ergot alkaloid production by certain grass associates and by several species of entomopathogenic Cordyceps with the objective of more clearly defining the evolutionary history, derivation, and biological significance of ergot alkaloids within the family.

Influence of the Ryegrass Endophyte on Phyto-Nematodes

Abstract: Ryegrass endophyte (Neotyphodium lolii) mediated resistance to Argentine stem weevil (Listronotus bonariensis) (ASW) (Prestidge et al., 1982) proved to be the first of an increasing number of pasture pests against which endophytes provide some level of protection. Latch (1993) lists 24 insect species and 6 nematode species affected by the presence of endophytes of perennial ryegrass and/or tall fescue.

Significance of Endophyte Toxicosis and Current Practices in Dealing with the Problem in South America

Abstract: The agronomic and economic significance of Neotyphodium related toxicoses in South America is strongly associated with the relative importance and localization of the two main forage grasses that host Neotyphodium endophytes, namely tall fescue (Festuca arundinacea Schreb.) and perennial ryegrass (Lolium perenne L.).

The Effects of Neotyphodium-Infected Perennial Ryegrass on the Abundance of Invertebrate Predators

Abstract: Plant feeding insects live in a world dominated on the one hand by their natural enemies and on the other by a nutritionally inadequate, and often poisonous food supply. Although there are more than 40 known species of plant feeding insect adversely affected by Neotyphodium-infected plants (Prestidge and Ball 1996), the effects of N. lolii on the predators of herbivorous insects are unknown. This information is required, as often the interaction of insect pests and natural enemies are extremely complex. The development of a database of Neotyphodium-sensitive invertebrate species prior to the widespread introduction of selected endophyte/grass associations is imperative so that concerns about environmental disturbance and loss of endemic species are avoided. This paper reports on the abundance of common ground dwelling predatory invertebrates in a large field trial sown with N. lolii-infected and N. lolii-free perennial ryegrass.

Influence of Neotyphodium Infection on Plant Survival of Diseased Tall Fescue and Ryegrass

Abstract: Basal necrosis resulting in death of tall fescue (Festuca arundinacea) and perennial ryegrass (Lolium perenne) plants has been a problem when pasteurised soil has been used to investigate abiotic stresses on grasses in a greenhouse trial. The likelihood that plant death was at least partly due to fungal pathogens was indicated by the isolation of Fusarium species (F. crookwellense, F. culmorum, F. oxysporum) and Microdochium bolleyi from the necrotic lower crowns and upper roots of affected ryegrass plants (M J Christensen, unpubl. data). The development of basal necrosis in tall fescue and perennial ryegrass plants growing in pasteurised sand in a greenhouse in Hamilton, Victoria, in preparation for a trial to assess tolerance to drought stress, provided an opportunity to assess the influence of endophyte infection on the development of this condition.

Field Performance of Tall Fescue with Low Infection with Neotyphodium Endophyte

Abstract: Tall fescue is used in New Zealand to provide quality summer herbage in summer-dry areas, and to provide a ryegrass staggers-free pasture in regions where perennial rye-grass can only persist if infected with ryegrass endophyte (Easton et al. 1994). Volunteer tall fescue growing on roadsides and on farm waste areas is heavily infected with the tall fescue endophyte, Neotyphodium coenophialum, and has long been known to be toxic to livestock. Tall fescue sold in New Zealand for use in pastures is free of endophyte.