Showing papers on "Neotyphodium published in 2014"

Nomenclatural realignment of Neotyphodium species with genus Epichloë

Abstract: Nomenclatural rule changes in the International Code of Nomenclature for algae, fungi and plants, adopted at the 18th International Botanical Congress in Melbourne, Australia, in 2011, provide for a single name to be used for each fungal species. The anamorphs of Epichloe species have been classified in genus Neotyphodium, the form genus that also includes most asexual Epichloe descendants. A nomenclatural realignment of this monophyletic group into one genus would enhance a broader understanding of the relationships and common features of these grass endophytes. Based on the principle of priority of publication we propose to classify all members of this clade in the genus Epichloe. We have reexamined classification of several described Epichloe and Neotyphodium species and varieties and propose new combinations and states. In this treatment we have accepted 43 unique taxa in Epichloe, including distinct species, subspecies, and varieties. We exclude from Epichloe the two taxa Neotyphodium starrii, as nom...

Characterization of Epichloë coenophiala within the US: are all tall fescue endophytes created equal?

Abstract: Tall fescue (Lolium arundinaceum) is a valuable and broadly adapted forage grass that occupies approximately 14 million hectares across the United States. A native to Europe, tall fescue was likely introduced into the U.S. around the late 1800’s. Much of the success of tall fescue can be attributed to Epichloe coenophiala (formerly Neotyphodium coenophialum) a seed borne symbiont that aids in host persistence. Epichloe species are capable of producing a range of alkaloids (ergot alkaloids, indole-diterpenes, lolines and peramine) that provide protection to the plant host from herbivory. Unfortunately, most tall fescue within the U.S., commonly referred to as KY31, harbors the endophyte E. coenophiala that causes toxicity to grazing livestock due to the production of ergot alkaloids. Molecular analyses of tall fescue endophytes have identified four independent associations, representing tall fescue with E. coenophiala, Epichloe sp. FaTG-2, Epichloe sp. FaTG-3 or Epichloe sp. FaTG-4. Each of these Epichloe species can be further distinguished based on genetic variation that equates to differences in the alkaloid gene loci. Tall fescue samples were evaluated using markers to SSR and alkaloid biosynthesis genes to determine endophyte strain variation present within continental U.S. Samples represented seed and tillers from the Suiter farm (Menifee County, KY), which is considered the originating site of KY31, as well as plant samples collected from 14 states, breeder’s seed and plant introduction lines (National Plant Germplasm System, NPGS). This study revealed two prominent E. coenophiala genotypes based on presence of alkaloid biosynthesis genes and SSR markers and provides insight into endophyte variation within continental U.S. across historical and current tall fescue samples.

Metabolite analysis of the effects of elevated CO2 and nitrogen fertilization on the association between tall fescue (Schedonorus arundinaceus) and its fungal symbiont Neotyphodium coenophialum.

Abstract: GR was supported by a fellowship from the Natural Science and Engineering Research Council (NSERC) Canada. Funding to support this research was provided by grants from NSERC and the Ontario Ministry of Agriculture, Food and Rural Affairs, to JN.

Agronomic advantages conferred by endophyte infection of perennial ryegrass (Lolium perenne L.) and tall fescue (Festuca arundinacea Schreb.) in Australia

Abstract: Perennial ryegrass and tall fescue are key grasses of sown pastures in the high-rainfall zone of south-eastern Australia. Ryegrass in naturalised pastures, and in sown seed, is widely infected with Neotyphodium fungal endophytes, with toxic endophyte strains occasionally causing toxicosis in livestock. Endophyte infection is also beneficial in sown grasslands, assisting ryegrass hosts to overcome biotic stresses, and tall fescue hosts to overcome biotic and abiotic stresses. We review the literature for Australia and present new data, to examine the agronomic effects of endophyte. Frequency of endophyte infection in old, perennial ryegrass pastures and ecotype-based cultivars is high and, in all pastures, increases with time, providing evidence for endophyte-infected plants having an agronomic advantage over endophyte-free plants. Within a cultivar, agronomic field experiments have compared endophyte-infected with endophyte-free swards. Endophyte significantly improved ryegrass establishment in seven of 19 measurements taken from 12 trials. In mature ryegrass pastures, over half of the experiments found advantages to endophyte infection. Tall fescues infected with a selected endophyte (‘AR542’) had improved agronomic performance relative to endophyte-free in a majority of experiments, and on occasions, the endophyte was essential for tall fescue persistence. Cultivar × endophyte interactions occurred but were inconsistent. In high-stress environments, endophyte was more important for agronomic performance than difference between cultivars. The relative importance of cultivar and endophyte is discussed, with elite cultivars that are adapted to the region and are infected with elite endophytes being the best avenue to capture the benefits and minimise detrimental endophyte effects on livestock. The major drivers are likely to be insect pests and drought, but evidence is limited.

Loline alkaloid production by fungal endophytes of Fescue species select for particular epiphytic bacterial microflora

Abstract: The leaves of fescue grasses are protected from herbivores by the production of loline alkaloids by the mutualist fungal endophytes Neotyphodium sp. or Epichloe sp. Most bacteria that reside on the leaf surface of such grasses can consume these defensive chemicals. Loline-consuming bacteria are rare on the leaves of other plant species. Several bacterial species including Burkholderia ambifaria recovered from tall fescue could use N-formyl loline as a sole carbon and nitrogen source in culture and achieved population sizes that were about eightfold higher when inoculated onto plants harboring loline-producing fungal endophytes than on plants lacking such endophytes or which were colonized by fungal variants incapable of loline production. In contrast, mutants of B. ambifaria and other bacterial species incapable of loline catabolism achieved similarly low population sizes on tall fescue colonized by loline-producing Neotyphodium sp. and on plants lacking this endophytic fungus. Lolines that are released onto the surface of plants benefiting from a fungal mutualism thus appear to be a major resource that can be exploited by epiphytic bacteria, thereby driving the establishment of a characteristic bacterial community on such plants.

Epichloë fungal endophytes and the formation of synthetic symbioses in Hordeeae (=Triticeae) grasses

Abstract: This review examines two classes of organism that live in symbiosis; grasses, and fungi. Specifically it deals with grasses of the tribe Hordeeae (formerly Triticeae) of the subfamily Pooideae and the Epichloe fungi of family Clavicipitaceae. Epichloe endophytes, particularly asexual forms, have important roles in pastoral agricultural systems in the Americas, Australia, and New Zealand. Selected strains add value to some grass-based forage systems by providing both biotic and abiotic stress resistance. The importance of cereal grasses such as wheat, barley, rye, and oats to human and animal nutrition and indeed to the foundation and maintenance of human civilization is well documented. Both organism classes, Epichloe endophytes and cereal grasses, are of great importance in their own contexts. Here, we seek to review these two classes of organism and examine the possibility of bringing them together in symbiosis with the ultimate goal of improving cereal production systems.

Neotyphodium Coenophialum-Infected Tall Fescue and Its Potential Application in the Phytoremediation of Saline Soils

Abstract: The growth response of endophyte-infected (EI) and endophyte-free (EF) tall fescue to salt stress was investigated under two growing systems (hydroponic and soil in pots). The hydroponic experiment...

An isolate of Epichloë festucae , an endophytic fungus of temperate grasses, has growth inhibitory activity against selected grass pathogens

Abstract: The symbiotic association of epichloae endophytes (Epichloe/Neotyphodium species) with temperate grasses of the subfamily Pooideae is known to enhance plant host tolerance to abiotic and biotic stresses. While the protection of the host plant from insect herbivory by epichloae endophytes is well characterized, the mechanism by which they protect their host against grass pathogens is largely unknown. Here, we assessed a geographically diverse collection of 14 Epichloe festucae isolates for in vitro antifungal activity against 8 grass pathogens. Isolate E437 of E. festucae, which had the broadest antifungal spectrum, inhibited growth of Drechslera erythrospila, D. siccans, D. dictyoides, Colletotrichum graminicola and Bipolaris sorokiniana. As shown with confocal microscopy, the endophyte reduced hyphal tip growth and differentiation of the pathogen, but did not cause any lysis. The isolate produced a thermostable, low-molecular-weight antifungal compound in culture. Disease symptoms caused by D. erythrospila on perennial ryegrass plants infected with E437 were reduced, suggesting the antifungal compound produced by E. festucae E437 isolate could be involved in the protection of the host plant.

Does fungal endophyte infection improve tall fescue's growth response to fire and water limitation?

Abstract: Invasive species may owe some of their success in competing and co-existing with native species to microbial symbioses they are capable of forming. Tall fescue is a cool-season, non-native, invasive grass capable of co-existing with native warm-season grasses in North American grasslands that frequently experience fire, drought, and cold winters, conditions to which the native species should be better-adapted than tall fescue. We hypothesized that tall fescue’s ability to form a symbiosis with Neotyphodium coenophialum, an aboveground fungal endophyte, may enhance its environmental stress tolerance and persistence in these environments. We used a greenhouse experiment to examine the effects of endophyte infection (E+ vs. E−), prescribed fire (1 burn vs. 2 burn vs. unburned control), and watering regime (dry vs. wet) on tall fescue growth. We assessed treatment effects for growth rates and the following response variables: total tiller length, number of tillers recruited during the experiment, number of reproductive tillers, tiller biomass, root biomass, and total biomass. Water regime significantly affected all response variables, with less growth and lower growth rates observed under the dry water regime compared to the wet. The burn treatments significantly affected total tiller length, number of reproductive tillers, total tiller biomass, and total biomass, but treatment differences were not consistent across parameters. Overall, fire seemed to enhance growth. Endophyte status significantly affected total tiller length and tiller biomass, but the effect was opposite what we predicted (E−>E+). The results from our experiment indicated that tall fescue was relatively tolerant of fire, even when combined with dry conditions, and that the fungal endophyte symbiosis was not important in governing this ecological ability. The persistence of tall fescue in native grassland ecosystems may be linked to other endophyte-conferred abilities not measured here (e.g., herbivory release) or may not be related to this plant-microbial symbiosis.

Species diversity of Epichloë symbiotic with two grasses from southern Argentinean Patagonia

Abstract: In this work we performed morphological and molecular phylogenetic analyses (based on sequences of calmodulin M [calM], translation-elongation factor 1-α [tefA] and β-tubulin [tubB] genes) to characterize the diversity of Epichloe endophytes in Bromus setifolius and Phleum alpinum. The phylogenies obtained from the three genes were congruent and allowed differentiation of three lineages of endophytes that also presented morphological differences. One lineage corresponds to the previously described species Epichloe tembladerae, which is present in a wide range of native grasses from Argentina including B. setifolius and P. alpinum. Another genotype isolated only from B. setifolius is a non-hybrid endophyte, a rare condition for the South American Epichloe endophytes. Isolates of this genotype, described herein as a new variety, Epichloe typhina var. aonikenkana, presented waxy colonies at maturity and a low production of conidia. The third lineage, exclusively found in isolates from P. alpinum, is a hybrid between E. typhina and a common ancestor of E. amarillans and E. baconii. Isolates of this lineage produce abundant conidia that are variable in shape and size. Based on its unique phylogenetic position and morphology, we propose the new species, Epichloe cabralii for this lineage. The new combinations Epichloe tembladerae and E. pampeana also are proposed for the previously described Neotyphodium tembladerae and Neotyphodium pampeanum species.

Cytotoxic effect of ergot alkaloids in Achnatherum inebrians infected by the Neotyphodium gansuense endophyte.

Abstract: Ergonovine or ergonovinine was isolated from the aerial parts of endophyte (Neotyphodium gansuense) infected (E+) drunken horse grass (Achnatherum inebrians), neither of which existed in endophyte-free (E-) plants. Both of these ergot alkaloids had a cytotoxic effect on animal smooth muscle cells and increased cell growth inhibition with greater concentrations, in a significantly (P < 0.05) positive correlation. The median inhibitory concentrations (IC50) for ergonovine and ergonovinine were 71.95 and 72.75 μg/mL, respectively. These results indicate that endophytic ergot alkaloids may be the cause of drunken horse grass poisoning.

The role of the Oregon State University Endophyte Service Laboratory in diagnosing clinical cases of endophyte toxicoses.

Abstract: The Oregon State University Colleges of Veterinary Medicine and Agricultural Sciences instituted the Endophyte Service Laboratory to aid in diagnosing toxicity problems associated with cool-season grasses in livestock. The endophyte (Neotyphodium coenophalum) present in tall fescue (Festuca arundinacea) produces ergopeptine alkaloids, of which ergovaline is the molecule used to determine exposure and toxicity thresholds for the vasoconstrictive conditions "fescue foot" and "summer slump". Another vasoconstrictive syndrome, "ergotism," is caused by a parasitic fungus, Claviceps purpurea, and its primary toxin, ergotamine. "Ryegrass staggers" is a neurological condition that affects livestock consuming endophyte (Neotyphodium lolii)- infected perennial ryegrass (Lolium perenne) with high levels of lolitrem B. HPLC-fluorescent analytical methods for these mycotoxins are described and were used to determine threshold levels of toxicity for ergovaline and lolitrem B in cattle, sheep, horses, and camels. In addition, six clinical cases in cattle are presented to illustrate diagnosis of these three diseases.

Ergot alkaloid intoxication in perennial ryegrass ( Lolium perenne ): an emerging animal health concern in Ireland?

Abstract: Four primary mycotoxicosis have been reported in livestock caused by fungal infections of grasses or cereals by members of the Clavicipitaceae family. Ergotism (generally associated with grasses, rye, triticale and other grains) and fescue toxicosis (associated with tall fescue grass, Festuca arundinacea) are both caused by ergot alkaloids, and referred to as ‘ergot alkaloid intoxication’. Ryegrass staggers (associated with perennial ryegrass Lolium perenne) is due to intoxication with an indole-diperpene, Lolitrem B, and metabolites. Fescue-associated oedema, recently described in Australia, may be associated with a pyrrolizidine alkaloid, N-acetyl norloline. Ergotism, caused by the fungus Claviceps purpurea, is visible and infects the outside of the plant seed. Fescue toxicosis and ryegrass staggers are caused by Neotyphodium coenophalium and N. lolii, respectively. Fescue-associated oedema has been associated with tall fescue varieties infected with a specific strain of N. coenophialum (AR542, Max P or Max Q). The name Neotyphodium refers to asexual derivatives of Epichloe spp., which have collectively been termed the epichloe fungi. These fungi exist symbiotically within the grass and are invisible to the naked eye. The primary toxicological effect of ergot alkaloid involves vasoconstriction and/or hypoprolactinaemia. Ingestion of ergot alkaloid by livestock can cause a range of effects, including poor weight gain, reduced fertility, hyperthermia, convulsions, gangrene of the extremities, and death. To date there are no published reports, either internationally or nationally, reporting ergot alkaloid intoxication specifically associated with perennial ryegrass endophytes. However, unpublished reports from the Irish Equine Centre have identified a potential emerging problem of ergot alkaloid intoxication with respect to equines and bovines, on primarily perennial ryegrass-based diets. Ergovaline has been isolated in varying concentrations in the herbage of a small number of equine and bovine farms where poor animal health and performance had been reported. Additionally, in some circumstances changes to the diet, where animals were fed primarily herbage, were sufficient to reverse adverse effects. Pending additional information, these results suggest that Irish farm advisors and veterinarians should be aware of the potential adverse role on animal health and performance of ergot alkaloids from perennial ryegrass infected with endophytic fungi.

Bottom–up regulates top–down: the effects of hybridization of grass endophytes on an aphid herbivore and its generalist predator

Abstract: The ecological consequences of hybridization of microbial symbionts are largely unknown. We tested the hypothesis that hybridization of microbial symbionts of plants can negatively affect performance of herbivores and their natural enemies. In addition, we studied the effects of hybridization of these symbionts on feeding preference of herbivores and their natural enemies. We used Arizona fescue as the host-plant, Neotyphodium endophytes as symbionts, the bird cherry–oat aphid as the herbivore and the pink spotted ladybird beetle as the predator in controlled experiments. Neither endophyte infection (infected or not infected) nor hybrid status (hybrid and non-hybrid infection) affected aphid reproduction, proportion of winged forms in the aphid populations, aphid host-plant preference or body mass of the ladybirds. However, development of ladybird larvae was delayed when fed with aphids grown on hybrid (H+) endophyte infected grasses compared to larvae fed with aphids from non-hybrid (NH+) infected grasses, non-hybrid, endophyte-removed grasses (NH-) and hybrid, endophyte-removed (H-) grasses. Furthermore, adult beetles were more likely to choose all other types of grasses harboring aphids rather than H+ infected grasses. In addition, development of ladybirds was delayed when fed with aphids from naturally uninfected (E-) grasses compared to ladybirds that were fed with aphids from NH+ and NH- grasses. Our results suggest that hybridization of microbial symbionts may negatively affect generalist predators such as the pink spotted ladybird and protect herbivores like the bird cherry–oat aphids from predation even though the direct effects on herbivores are not evident.

Novel perennial ryegrass-Neotyphodium endophyte associations: relationships between seed weight, seedling vigour and endophyte presence

Abstract: Two forage cultivars of perennial ryegrass (Lolium perenne) colonised by the mutualistic fungal endophyte Neotyphodium lolii, strain AR37, were used to investigate relationships between seed weight, seed vigour and endophyte presence. Seed was separated into six fractions according to weight, with each fraction divided into two further groups with the first being subject to accelerated ageing. Seed germination rates and proportions of viable and total endophyte frequencies were assessed for each fraction. Heavier fractions of seed produced a higher number of endophyte infected seedlings sooner than the lighter fractions for both cultivars. The highest proportion of viable endophyte was found in the fastest germinating perennial ryegrass seed for all weight fractions, from both cultivars, indicating a strong relationship between endophyte presence and seed germination rate. For one of the cultivars, after accelerated ageing, as seed weight increased the proportion of viable endophyte increased and the discrepancy between the proportion of endophyte in fresh and accelerated aged seed was reduced. This implies that for this cultivar heavier ryegrass seed provides a more favourable habitat to the dormant endophyte than lighter seed during storage and/or allowed for a greater biomass of endophyte hyphae to proliferate in the seed tissues prior to seed dormancy, thus allowing the fungus to develop more propagules and greater nutritional reserves.

Asexual Endophytes of Grasses: Invisible Symbionts, Visible Imprints in the Host Neighborhood

Abstract: Asexual fungi from the genus Neotyphodium, relatives of the sexual epichloe species (Clavicipitaceae, Ascomycota), are symbionts of several cool-season grasses inhabiting virtually all terrestrial ecosystems. The host plants incur carbon costs to sustain this symbiosis, but, in return, they obtain multiple benefits from the fungal partners, above all, protection from herbivores. These endophytes are often considered to be defensive mutualists or private protectors because they produce a considerable range of secondary metabolites which prove to be toxic to livestock or deterrent to insects. Over the past decade, ecologists have begun to recognize the critical role played by this grass–endophyte symbiosis in the structure and functioning of natural and human-made communities. In this chapter, I will identify different pathways through which the presence of endophytic plants or their dead tissues (litter) can alter the fitness of nonsymbiotic plants. Those pathways lead to show how these symbionts impact on the establishment and productivity of nonsymbiotic neighbors and the interaction of the latter with multiple above- and belowground ecosystem components. A set of recent studies performed with plants of Lolium multiflorum associated with Neotyphodium occultans will provide experimental evidence to those effects. Finally, I will discuss the relevance of placing these pathways under the spotlight in order to understand the processes that determine the frequency of symbiotic plants within a population. Estimating endophyte impacts on host fitness must consider advantages or disadvantages transferred to conspecific plants in the neighborhood, coexisting as a consequence of inefficiencies during the transmission from plants to seeds.

Dynamics of Neotyphodium uncinatum and N-formylloline in Italian ryegrass, and their relation to insect resistance in the field.

Abstract: Aims A fungal endophyte, Neotyphodium uncinatum, accumulates N-formylloline, which is toxic to Hemipteran insects, in Italian ryegrass. This study aimed to clarify the dynamics of N. uncinatum and N-formylloline in Italian ryegrass, and their relationship to insect resistance. Methods and Results Changes in the density and localization of N. uncinatum and N-formylloline in N. uncinatum-infected Italian ryegrass were examined by real-time PCR and gas chromatography, respectively. Neotyphodium uncinatum multiplied on pseudostems at the flowering stage, and then increased on inflorescences at the ripening stage. On the other hand, N-formylloline accumulated heavily in inflorescences and leaf blades, but lightly in pseudostems at the ripening stage. In field experiments, N. uncinatum-infected Italian ryegrass suppressed the occurrence of Stenotus rubrovittatus, which fed on the inflorescences, but was not effective to Laodelphax striatellus, which do not necessarily prefer a particular plant tissue. Conclusion Localization of N. uncinatum and N-formylloline were discordant in Italian ryegrass. The N. uncinatum-infected Italian ryegrass was effective to only insects that prefer to feed on particular plant tissues containing N-formylloline. Significance and Impact of Study Our data implies that the relationship between insect habits and the dynamics of alkaloids in plants is important for the effective use of endophyte-infected crops.

Toxicité des mycotoxines produites par des champignons endophytes du genre Neotyphodium

Abstract: objectif de cette revue bibliographique est de faire un rappel des conditions historiques des survenues de ces affections, et une analyse des etudes cherchant a les reproduire experimentalement. Les mecanismes d’action toxiques supposes de l’ergovaline et du lolitrem B, ainsi que leurs toxicocinetiques et risques de persistance a l’etat residuel dans les productions animales et d’origine animale sont ensuite presentes. Mots-cles : Neotyphodium, endophytes, alcaloides ergotiques, lolitrem B, ergovaline, fescue foot, ryegrass staggers SUMMARY Toxicity of mycotoxins produced by endophytic fungi of the genus Neotyphodium The symbiotic associations between different varieties of fungi of the Neotyphodium kind and forages are responsible for the production of mycotoxins which are responsible of toxicoses in livestock and economic losses in some countries. The development of N. coenophialum in tall fescue, which is associated with the production of ergovaline, is responsible for « fescue foot disease » while the presence of N. lolii in ryegrass, which is accompanied by the production of lolitrem B, is responsible for the « ryegrass staggers ». The aim of this literature review is to recall the historical conditions on which these diseases occurred, followed by an analysis of studies seeking to experimentally reproduce the diseases. The supposed mechanisms of the toxic actions for ergovaline and lolitrem B, their toxicokinetics and the risk of persistence in the residual state in animal productions and animal origin are later presented.

Effects of grassland management, endophytic fungi and predators on aphid abundance in two distinct regions

Abstract: Aims Fungal endophytes of cool-season grass species produce alkaloids toxic to herbivores, affecting food webs in agricultural and natural ecosystems. Field studies about the effects of endophytes on herbivores are rare and show contradictory results, leading to uncertain conclusions about the nature of endophyte–grass symbiosis. We asked whether the environmental contexts of local and regional scales and predation could modify the effects of endophytes on herbivores. Methods In a full factorial field experiment, we quantified the abundance of the aphid species Rhopalosiphum padi on the potted host grass Lolium perenne, which was either infected or uninfected with the endophytic fungus Neotyphodium lolii. Predators were either excluded or had free access to the pots with the aphids. One hundred and sixty grass pots were located in two regions on altogether 40 grassland sites, half of the sites intensively and half extensively managed. We tested the importance of endophyte infection, study region, management intensity of grasslands, predation and all twoway interactions on aphid abundance. Important Findings Endophyte infection reduced aphid abundance significantly in one study region only. In both regions, we found that the impacts of aphidophagous predators and grassland management intensity on aphid abundance were substantially stronger and more consistent than that of endophytes on aphid abundance. Pots excluding predators and pots placed on extensive grasslands contained higher aphid abundance. The impact of predators and management on aphid abundance were not modified by the endophyte. We conclude that the effect of endophytes on herbivores can be weak in field experiments and depends on environmental context at a regional scale. Hence, more field research efforts are necessary to detect the relative importance of endophytes and the environmental context on biotic interactions in ecosystems.

Antifungal activity of petroleum ether extracts from Achnatherum inebrians infected with Neotyphodium gansuense.

Abstract: (Hance) Keng (drunken horse grass, DHG) is a toxic perennial bunchgrass, which is so-named because it is associated with the narcosis of livestock which graze on native grasslands in the northwest of China [1]. DHG is distributed mainly throughout the harsh conditions of alpine or sub-alpine grasslands, and this species is usual-ly infected by the fungal endophyte

The effect of endophyte presence on Schedonorus arundinaceus (tall fescue) establishment varies with grassland community structure

Abstract: The endophyte Neotyphodium coenophialum in Schedonorus arundinaceus (tall fescue) may alter host interactions with specific resident species or shift the host’s niche. These effects can be quantified by assessing tall fescue responses to, and effects on, the variation among resident species (selection) and resident species interactions (complementarity). To determine how N. coenophialum affects tall fescue, grassland microcosms containing 16 transplants of two, four, or eight resident species were seeded with endophyte-infected (E+) or endophyte-free (E−) Kentucky-31 (KY-31) tall fescue. All resident species were also grown in monoculture. Aboveground biomass was harvested 9 weeks after tall fescue was added (18 weeks’ total growth). At harvest, more E+ than E− individuals were present and they represented a larger portion of the aboveground biomass across richness treatments, despite similar germination in concurrent trials. Tall fescue individuals were larger in microcosms dominated by more productive resident species (greater selection). In contrast, fewer E−, but not E+, individuals were present in microcosms with more facilitative interactions among the resident species (greater complementarity). E− and E+ tall fescue also affected resident species differently. High-richness E+ microcosms were more diverse and less dominated by productive species (lower selection) than E− microcosms. Thus, E+ KY-31 may more readily establish in, and affect, species-rich, functionally diverse communities as a result of niche shifts during establishment and negative effects on specific resident species. Although results need to be further tested under field conditions, it appears that endophyte presence may only facilitate KY-31 invasion into a limited suite of community types.

Effect of Neotyphodium endophyte symbiosis on growth, Nickel uptake and photosynthetic pigments in two genotypes of tall fescue

Abstract: :هديكچ نيرتمهم زا نيگنس تازلف هب كاخ يگدولآ تارثا ناسنا هجيتن رد و يزرواشك تلاوصحم تملاس رب هك تسا يطيحم تسيز لئاسم چراق .تسا هتشاذگ ءوس چراق زا يهورگ تيافودنا ياه شخب رد ار دوخ يگدنز هرود مامت هك دنتسه اه نابزيم ناهايگ يياوه ياه يم چراق نيا .دننك داجيا هايگ رد ار يراميب مئلاع هكنيا نودب دننارذگ اه شنت هب نابزيم ناهايگ رتشيب تمواقم داجيا ببس يتسيز ياه يم يتسيز ريغ و ) دنلب يويكسف هايگ زا پيتونژ ود شهوژپ نيا رد .دنوش B 75 و C 75 تيافودنا چراق هب هدولآ تروص ود هب ( ) E ) چراق نودب و ( E كاخ رد ( تظلغ هب هدولآ ياه ياه 0 ، 30 ، 90 و ppm 180 هداد دشر راركت هس رد ،لكين سپ هام ود .دندش صخاش ،لكين راميت رد ناهايگ نتفرگ رارق زا مادنا و هشير رت نزو لماش دشر ياه مادنا هب هشير تبسن ،يياوه لكين بذج ،يياوه مادنا و هشير رد گرب ديئونتوراك و ليفورلك ياوتحم نينچمه و يياوه هزادنا اه ،جياتن قبط .دش يريگ چراق ببس تيافودنا ياه گرب رد ليفورلك ياوتحم شيازفا پيتونژ رد طقف ،لكين بذج شيازفا و پيتونژ ود ره ياه B 75 نينچمه جياتن .دندش اكوتسف پيتونژ تمواقم شيازفا و دشر دوبهب هدنهد ناشن B 75 دنلب يويكسف رد هكيلاح رد دوب تيافودنا اب يگدولآ رثا رد لكين شنت هب پيتونژ C 75 يم قوف هجيتن .دنداد ناشن لكين شنت هب يرتشيب تمواقم تيافودنا دقاف ناهايگ هك دشاب بلطم نيا رگنايب دناوت چراق رثا يگنوگچ .تسا هتسباو نابزيم پيتونژ هب نابزيم هايگ رد تيافودنا ياه

Influence of grassland management on the abundance of the endophytic fungi Neotyphodium

Abstract: The endophytic fungus Neotyphodium spec. Glenn, Bacon and Hanlin is common in many temperate grass species. This fungus is known to enhance the resistance of its host to adverse environmental conditions and to promote its growth. In addition, Neotyphodium spec. produces a wide range of alkaloids and can therefore be toxic to livestock. Many studies dealing with this topic were conducted in the intensively managed grasslands of the USA and New Zealand. However, we still lack knowledge about the abundance of this fungus in cultivated grasslands in Europe under different management regimes. This information could contribute to a better understanding of the fungal ecology and help to assess the risk of toxicoses in European grasslands. Hence, the objective of this study was to investigate the impact of grassland management on the incidence of Neotyphodium spec. in different grass species. 1) In the rural district of Northeim (central Germany) the impact of land use intensity and type of grassland use on the incidence of Neotyphodium lolii (Latch, Christensen and Samuels), Glenn, Bacon and Hanlin in perennial ryegrass (Lolium perenne L.) was investigated in 90 managed grasslands. - The mean infection rate of L. perenne with N. lolii was low. - The intensity of land use (extensive, intermediate, intensive) and the type of grassland (pasture, mown pasture, meadow) had no influence on the abundance of the fungus. - Geology significantly influenced the incidence of N. lolii: L. perenne plants collected from sites with limestone bedrock had higher infection rates than plants from other soils. 2) The influence of fertilization, cutting frequency and sward composition on the abundance of Neotyphodium spec. in four grass species was tested in an experimental grassland in the Solling Uplands, central Germany. - Cutting frequency and sward composition did not influence the incidence of Neotyphodium spec. - Fertilization significantly increased the infection rate of the tested grass species compared to non-fertilized plots. 3) It was tested how grazing of cattle, sheep and co-grazing of cattle and sheep under different diversity regimes (high and low sward diversity) influences the abundance of Neotyphodium spec. in L. perenne and Festuca pratensis Huds. (meadow fescue). This investigation was carried out in an experimental pasture in the Solling Uplands, central Germany. - In the high diversity treatment grazing and co-grazing of cattle and sheep had no influence on the abundance of the fungus in both grass species. - In the low diversity treatment the incidence of Neotyphodium unicatum (Gams, Petrini and Schmidt) Glenn, Bacon, Price and Hanlin in F. pratensis was significantly higher in plots co-grazed by cattle and sheep compared to plots grazed by sheep only. In contrast, there was no difference in the abundance of N. lolii in L. perenne between the grazing treatment

The effect of Neotyphodium grass endophyte on alkaloid profiles, dry matter production and botanical composition of perennial ryegrass pastures

Abstract: of a thesis submitted in partial fulfilment of the requirements for the Degree of Master of Agricultural Science. Abstract The effect of Neotyphodium grass endophyte on alkaloid profiles, dry matter production and botanical composition of perennial ryegrass pastures by Sarah Louise McKenzie This study involved three key experiments to examined the effect of Nil endophtye and novel endophyte strains (AR1, AR37, Wild-Type (WT) and NEA2) of perennial ryegrass on dry-matter (DM) production, botanical compositon, alkaloid profiles and possible effects on soil-pasture ecosystems interactions. A field trial measured DM production and composition of perennial ryegrass pastures sown with a diversity treatment of with or without additional prairie grass, herb (chicory) and legume (white clover). In the same trial, alkaloid and endophyte concentrations were examined in dissected vegetative grass tillers to ascertain how alkaloids may potentially leave the plant and affect soilpasture ecosystems. Finally, a pot trial comparing the addition of live or dead perennial ryegrass plant material was used to examine the effect of endophyte strain on the growth of associated pasture species. There was no effect of endophyte or diversity treatment on the total or seasonal herbage DM production of the field trial, with a non-significant 18,540 kg DM/ha and 18,090 kg DM/ha total yield for the diverse and monoculture treatments respectively over the 16 months of the trial. There was a significant endophyte x diversity interaction in spring 2011 when monocultures of Nil and AR37 (5638 and 4963 kg DM/ha respectively) yielded significantly higher than that of their equivalent diverse pastures (4099 and 4323 kg DM/ha). It is unclear the reasoning for this interaction. The different seasons showed significant differences in the proportion of white clover in the diverse swards with the highest in summer, and the lowest in winter (25% and 11% respectively as a porportion of the total sward DM). There were minimal effects of endophyte on botanical composition, with no significant differences for monocultures. The proportion of prairie grass present in summer 2010/11 was significantly higher in WT diverse plots than other endophytes and spring 2011 showed higher chicory present in WT and NEA2 diverse plots over AR37.