Showing papers on "Neotyphodium published in 2010"

The Epichloae, Symbionts of the Grass Subfamily Poöideae1

Abstract: Symbioses of grasses (Poaceae) with fungi of family Clavicipitaceae vary widely in relative benefits and detriments to the plant, and include mutualisms characterized by vertical transmission and protective effects of the fungus and its metabolites against vertebrate and invertebrate herbivores. This review focuses on the epichloae, a group of fungi within the Clavicipitaceae that are symbiotic with members of the grass subfamily Pooideae and comprise sexual fungi of genus Epichloe (Fr.) Tul. & C. Tul. and their asexual derivatives (form genus Neotyphodium A. E. Glenn, C. W. Bacon & R. T. Hanlin). Most epichloid fungi are vertically transmissible, and many produce antiherbivore alkaloids belonging to any of four distinct chemical classes: lolines, peramine, ergot alkaloids, and indole-diterpenes. Like many plant-associated Clavicipitaceae, fruiting of Epichloe species chokes host inflorescences, preventing seed production on the affected tillers. However, most Epichloe-infected grasses also produ...

Effect of Endophytic Fungi on Cadmium Tolerance and Bioaccumulation by Festuca Arundinacea and Festuca Pratensis

Abstract: Endophytic fungi are a group of fungi that live asymptomatically inside plant tissue. These fungi may increase host plant tolerance to biotic and abiotic stresses. The effect of Neotyphodium endophytes in two grass species (Festuca arundinacea and Festuca pratensis) on cadmium (Cd) tolerance, accumulation and translocation has been our main objective. The plants were grown in a hydroponic system under different Cd concentrations (0, 5, 10, and 20 mg L(-1)) for 6 weeks. They were also grown in soil spiked with different concentrations of Cd (0, 10, 20, and 40 mg kg(-1)) for 2 months. The results from all Cd treatments showed higher biomass production (12-24%) and higher potential to accumulate Cd in roots (6-16%) and shoots (6-20%) of endophyte-infected plants than endophyte-free plants. Cadmium accumulation by plants indicated that the grasses were capable of Cd hyperaccumulation, a property that was augmented after endophyte infection. Maximum photochemical efficiency of photosystem II (Fv/Fm) revealed that Cd stress was significantly reduced in endophyte-infected plants compared to non-infected ones.

Neotyphodium endophytes trigger salt resistance in tall and meadow fescues

Abstract: Infection with Neotyphodium spp. endophytes increases resistance to drought stress and soil mineral imbalances in tall fescue (Festuca arundinacea Schreb. = Lolium arundinaceum (Schreb.) S. J. Darbysh.) and meadow fescue (Festuca pratensis Huds. = Lolium pratense (Huds.) Darbysh.). We hypothesized that resistance of these grasses to salinity stress may also be attributed to endophyte infection. Two tall fescue genotypes, Fa75 and Fa83, and one meadow fescue genotype, Fp60, infected (E+) with their endophytic fungi, Neotyphodium coenophialum (Glenn, Bacon and Hanlin) and N. uncinatum (Glenn, Bacon and Hanlin), respectively, and their noninfected counterparts (E–) were cultured in nutrient solution at three salinity levels of 0, 85, and 170 mM NaCl. Except for genotype Fa75, E+ plants exhibited higher leaf survival rates than E– clones at a high salinity level (170 mM). Root dry matter was higher in E+ than in E– plants, but shoot dry matter was not affected by endophyte infection. This resulted in a lower shoot-to-root ratio in E+ plants (1.63) compared with E– plants (2.40). Sodium (Na+) and chloride (Cl–) concentrations were greater in roots of E– than in E+ clones. In shoots, Na+ and Cl– concentrations were not affected by the endophyte. In contrast, E+ plants accumulated more potassium (K+), which resulted in a greater K+ : Na+ ratio in shoots of E+ than in those of E– plants. Our results show that endophyte infection reduced Na+ and Cl– concentrations in tall fescue and meadow fescue roots but increased K+ concentrations in the shoots. Based on these results, we conclude that endophyte-infected grasses may thrive better in salinity-stress environments.

Managing plant symbiosis: fungal endophyte genotype alters plant community composition

Abstract: Summary 1. Understanding the extent to which plant genotype influences community composition has important conservation and management value. Here, we add a new layer to current research by testing whether genotypes of plant symbionts influence plant community composition. 2. Tall fescue grass Lolium arundinaceum is planted worldwide for forage, turf, and soil stabilization, has invaded native communities, and commonly hosts the foliar endophytic fungus, Neotyphodium coenophialum. We quantified vegetation development over a 6-year period in replicated field plots of the two most commonly introduced genotypes of the endophyte (KY-31, AR-542) in two tall fescue cultivars (Georgia-5, Jesup). The KY-31 endophyte produces ergot alkaloids toxic to mammalian herbivores, while AR-542 lacks ergots. We expected that the KY-31 endophyte would promote tall fescue dominance by altering mammalian herbivory, that endophyte-free plots would support the highest plant diversity, and that AR-542 endophyte would show intermediate effects. 3. Plots with the KY-31 endophyte supported 10% fewer plant species than endophyte-free or AR-542 plots. KY-31 also reduced graminoids and forbs more strongly than AR-542, with the greatest response in Georgia-5. Endophyte genotype did not significantly alter the prevalence of tall fescue; however, absence of the endophyte reduced the biomass of Georgia-5. 4. Both plant and endophyte genetic identity influenced the persistence of endophyte symbiosis. In Georgia-5, the frequency of AR-542 declined more through time than did KY-31; these effects were reversed in Jesup. 5. Endophyte presence reduced herbivory by mammals (voles), but endophyte genotype had no effect, suggesting that voles were not driving endophyte genotype-mediated changes in plant composition, and that other compounds besides ergot alkaloids influenced vole feeding. 6. Synthesis and applications. When endophyte-symbiotic plants are desired, the AR-542 endophyte in the Georgia-5 background would achieve higher native plant diversity and reduce tall fescue invasion of nearby areas. Conversely, Jesup is recommended for increased tall fescue persistence, as both biomass and reproduction exceeded Georgia-5. In summary, our results demonstrate that, like plant genotype, symbiont genotype can also alter vegetation dynamics and plant composition and should be considered when managing for conservation, restoration, forage, turf, re-vegetation or soil stabilization.

Asexual endophytes and associated alkaloids alter arthropod community structure and increase herbivore abundances on a native grass

Abstract: Despite their minute biomass, microbial symbionts of plants potentially alter herbivory, diversity and community structure. Infection of grasses by asexual endophytic fungi often decreases herbivore loads and alters arthropod diversity. However, most studies to date have involved agronomic grasses and often consider only infection status (infected vs. uninfected), without explicitly measuring endophyte-produced alkaloids, which vary among endophyte isolates and may impact consumers. We combined field experiments and population surveys to investigate how endophyte infection and associated alkaloids influence abundances, species richness, evenness and guild structure of arthropod communities on a native grass, Achnatherum robustum (sleepygrass). Surprisingly, we found that endophyte-produced alkaloids were associated with increased herbivore abundances and species richness. Our results suggest that, unlike what has been found in agronomic grass systems, high alkaloid levels in native grasses may not protect host grasses from arthropod herbivores, and may instead more negatively affect natural enemies of herbivores.

The interplay between the effectiveness of the grass-endophyte mutualism and the genetic variability of the host plant.

Abstract: Neotyphodium endophytic fungi, the asexual state of Epichloe species, protect cool-season grasses against stresses. The outcomes of Neotyphodium-grass symbioses are agronomically relevant as they may affect the productivity of pastures. It has been suggested that the mutualism is characteristic of agronomic grasses and that differential rates of gene flow between both partners’ populations are expected to disrupt the specificity of the association and, thus, the mutualism in wild grasses. We propose that compatibility is necessary but not sufficient to explain the outcomes of Neotyphodium-grass symbiosis, and advance a model that links genetic compatibility, mutualism effectiveness, and endophyte transmission efficiency. For endophytes that reproduce clonally and depend on allogamous hosts for reproduction and dissemination, we propose that this symbiosis works as an integrated entity where gene flow promotes its fitness and evolution. Compatibility between the host plant and the fungal endophyte would be high in genetically close parents; however, mutualism effectiveness and transmission efficiency would be low in fitness depressed host plants. Increasing the genetic distance of mating parents would increase mutualism effectiveness and transmission efficiency. This tendency would be broken when the genetic distance between parents is high (out-breeding depression). Our model allows for testable hypotheses that would contribute to understand the coevolutionary origin and future of the endophyte-grass mutualism.

Inherited microbial symbionts increase herbivore abundances and alter arthropod diversity on a native grass

Abstract: Some microbial symbionts of plants are maternally inherited and thus functionally increase genetic and phenotypic variation within plant populations. This variation, coupled with that of the host plant and environment, may alter abundances, diversity, and trophic structure of associated plant and animal communities. Fungal endophytes in the genus Neotyphodium are vertically transmitted, asexual microbial symbionts of grasses that remain asymptomatic and rely upon their hosts for resources and transmission via seeds, often providing benefits to their hosts, including protection against herbivores. Endophyte infections may influence associated arthropod communities in agronomic grasses, but the long-term effects of endophytes and variation in host genotype and resource availability on arthropod communities in native grass populations are unknown. We conducted a long-term field experiment with four maternal genotypes of an infected (E+) native grass (Festuca arizonica) from whence the endophyte was experimentally removed (E-) and water availability was controlled, to test the effects of infection, plant genotype, and resources on abundances, biomass, diversity (richness and evenness), and trophic structure of the arthropod community. Generally, E+ grasses harbored more arthropods, including more herbivores, predators, and detritivores, suggesting that the effects of endophytes cascaded upward through trophic levels in terms of abundances, at least in early ontogeny of the host. That E+ plants harbored more herbivorous insects than E- plants suggests that infection does not increase but instead decreases resistance to herbivores, contrary to prevailing concepts of endophytes as defensive mutualists. Infection did not alter overall species richness of the arthropod community or richness of herbivores but reduced natural enemy richness, especially that of parasites, and increased richness of detritivores. Reduced richness and shifts in evenness of natural enemies on E+ plants suggest that endophytes may disproportionately affect diversity at higher trophic levels and may partially explain increases in abundances of herbivorous insects on E+ plants. Biomass of predators, detritivores, and omnivores increased on plants with supplemented water, and arthropod and herbivore biomass varied by plant genotype. Symbiont-mediated phenotypic variation interacts with variation from plant genotype and environmental factors to alter arthropod abundances and diversity, and these effects shift with ontogeny of the host.

Hybridization in Endophyte Symbionts Alters Host Response to Moisture and Nutrient Treatments

Abstract: When a host organism is infected by a symbiont, the resulting symbiotum has a phenotype distinct from uninfected hosts. Genotypic interactions between the partners may increase phenotypic variation of the host at the population level. Neotyphodium is an asexual, vertically transmitted endophytic symbiont of grasses often existing in hybrid form. Hybridization in Neotyphodium rapidly increases the symbiotum’s genomic content and is likely to increase the phenotypic variation of the host. This phenotypic variation is predicted to enhance host performance, especially in stressful environments. We tested this hypothesis by comparing the growth, survival, and resource allocation of hybrid and nonhybrid infected host plants exposed to controlled variation in soil moisture and nutrients. Infection by a hybrid endophyte did not fit our predictions of comparatively higher root and total biomass production under low moisture/low nutrient treatments. Regardless of whether the host was infected by a hybrid or nonhybrid endophyte, both produced significantly higher root/total biomass when both nutrient and moisture were high compared to limited nutrient/moisture treatments. However, infection by hybrid Neotyphodium did result in significantly higher total biomass and host survival compared to nonhybrid infected hosts, regardless of treatment. Endophyte hybridization alters host strategies in response to stress by increasing survival in depauperate habitats and thus, potentially increasing the relative long-term host fitness.

Do the costs and benefits of fungal endophyte symbiosis vary with light availability

Abstract: • Here, we examined whether fungal endophytes modulated host plant responses to light availability. First, we conducted a literature review to evaluate whether natural frequencies of endophyte symbiosis in grasses from shaded habitats were higher than frequencies in grasses occupying more diverse light environments. Then, in a glasshouse experiment, we assessed how four levels of light and the presence of endophyte symbioses affected the growth of six grass species. • In our literature survey, endophytes were more commonly present in grasses restricted to shaded habitats than in grasses from diverse light environments. • In the glasshouse, endophyte symbioses did not mediate plant growth in response to light availability. However, in the host grass, Agrostis perennans, symbiotic plants produced 53% more inflorescences than nonsymbiotic plants at the highest level of shade. In addition, under high shade, symbiotic Poa autumnalis invested more in specific leaf area than symbiont-free plants. Finally, shade increased the density of the endophyte in leaf tissues across all six grass species. • Our results highlight the potential for symbiosis to alter the plasticity of host physiological traits, demonstrate a novel benefit of endophyte symbiosis under shade stress for one host species, and show a positive association between shade-restricted grass species and fungal endophytes.

Dynamics of Neotyphodium endophyte infection in ageing seed pools: incidence of differential viability loss of endophyte, infected seed and non-infected seed

Abstract: Symbiotic associations between grasses and vertically transmitted endophytic fungi are widespread in nature. Within grass populations, changes in the frequency of infected plants are driven by influence of the endophyte on the fitness of their hosts and by the efficiency of endophyte transmission from parent plants to their offspring. During the seed stage, the endophyte might influence the fitness of its host by affecting the rate of seed viability loss, whereas the efficiency of endophyte transmission is affected by losses of viability of the fungus within viable seeds. We assessed the viability losses of Lolium multiflorum seeds with high and low level of infection of the endophyte Neotyphodium occultans, as well as the loss of viability of the fungus itself, under accelerated seed ageing and under field conditions. Starting with high endophyte-infected accessions of L. multiflorum, we produced their low endophyte-infected counterparts by treating seeds with a fungicide, and subsequently multiplying seeds in adjacent plots allowing pollen exchange. In our accelerated ageing experiments, which included three accessions, high endophyte-infected seeds lost viability significantly faster than their low endophyte-infected counterpart, for only one accession. High endophyte-infected seeds of this particular accession absorbed more water than low endophyte-infected seeds. In contrast, the endophyte lost viability within live seeds of all three accessions, as the proportions of viable seeds producing infected seedlings decreased over time. In our field experiment, which included only one accession, high endophyte-infected seed lost viability significantly but only slightly faster than low endophyte-infected seed. In contrast, the loss of viability of the endophyte was substantial as the proportions of viable seeds producing infected seedlings decreased greatly over time. Moving the seeds from the air to the soil surface (simulating seed dispersion off the spikes) decreased substantially the rate of seed viability loss, but increased the rate of endophyte viability loss. Our experiments suggest that, in ageing seed pools, endophyte viability loss and differential seed mortality determine decreases in the proportions of endophyte-infected seeds in L. multiflorum. Endophyte viability loss within live seeds contributes substantially more to infection frequency changes than differential viability losses of infected and non-infected seeds.

Development of a bird-deterrent fungal endophyte in turf tall fescue

Abstract: Two Neotyphodium fungal endophyte strains (AR601 and AR604) that produce high levels of ergovaline and loline alkaloids were inoculated into turf tall fescue for the purpose of producing symbioses that deter birds. The endophyte–grass associations were shown to be stably transmitted and, in preliminary experiments, reduced insect and bird numbers at an airport and reduced faecal contamination of a sports field by birds. Cultivar ‘Jackal’ infected with endophyte strain AR601 has been released commercially.

Asexual Endophytes in a Native Grass: Tradeoffs in Mortality, Growth, Reproduction, and Alkaloid Production

Abstract: Neotyphodium endophytes are asexual, seed-borne fungal symbionts that are thought to interact mutualistically with their grass hosts. Benefits include increased growth, reproduction, and resistance to herbivores via endophytic alkaloids. Although these benefits are well established in infected introduced, agronomic grasses, little is known about the cost and benefits of endophyte infection in native grass populations. These populations exist as mosaics of uninfected and infected plants, with the latter often comprised of plants that vary widely in alkaloid content. We tested the costs and benefits of endophyte infections with varying alkaloids in the native grass Achnatherum robustum (sleepygrass). We conducted a 4-year field experiment, where herbivory and water availability were controlled and survival, growth, and reproduction of three maternal plant genotypes [uninfected plants (E−), infected plants with high levels of ergot alkaloids (E+A+), and infected plants with no alkaloids (E+A−)] were monitored over three growing seasons. Generally, E+A+ plants had reduced growth over the three growing seasons and lower seed production than E− or E+A− plants, suggesting a cost of alkaloid production. The reduction in vegetative biomass in E+A+ plants was most pronounced under supplemented water, contrary to the prediction that additional resources would offset the cost of alkaloid production. Also, E+A+ plants showed no advantage in growth, seed production, or reproductive effort under full herbivory relative to E− or E+A− grasses, contrary to the predictions of the defensive mutualism hypothesis. However, E+A+ plants had higher overwintering survival than E+A− plants in early plant ontogeny, suggesting that alkaloids associated with infection may protect against below ground herbivory or harsh winter conditions. Our results suggest that the mosaic of E−, E+A+, and E+A− plants observed in nature may result from varying biotic and abiotic selective factors that maintain the presence of uninfected plants and infected plants that vary in alkaloid production.

Co-occurring patterns of endophyte infection and genetic structure in the alpine grass, Festuca eskia : implications for seed sourcing in ecological restoration

Abstract: Choosing the provenance of seed used in ecological restoration could entail its success. An alternative approach to examine local adaptation in seed sourcing is the assessment of genetic structure and diversity based on molecular markers. These types of analyses focus on the genetics of the target plant itself and eliminate the genetic influence of associated organisms, such as Epichloe/Neotyphodium endophytes in grasses. By impacting the fitness of their host, such symbionts may influence population genetic structure and diversity. Therefore, seed sourcing for grasses must consider the influence of their endophytes to increase seed translocation success and minimize the risks associated with this practice. To delineate seed zones for restoration of the alpine fescue Festuca eskia Ramond ex. DC. (Poaceae), we assessed population genetic differentiation and diversity patterns in the species including endophyte occurrence along altitudinal and longitudinal gradients in the Pyrenees Mountains. Twenty-three populations were analysed for endophyte status, and three STS and one SSR marker were used to examine genetic differentiation and diversity patterns. Results showed that F. eskia hosts an asexual form of Epichloe and infection frequency within populations decreased from East to West (100 vs. 8–25%). Molecular markers separated F. eskia into two East and West groups, and endophyte infection and genetic patterns were congruent with molecular data. Little evidence for genetic differentiation or difference in endophyte occurrence associated with altitude was detected. Little variation was found in within population diversity, regardless of provenance altitude and site, and/or endophyte infection frequency. The results of this study suggested the establishment of two distinct management units for F. eskia seed sourcing restoration.

Are loline alkaloid levels regulated in grass endophytes by gene expression or substrate availability

Abstract: Many cool-season grasses (Poaceae, subfam. Pooideae) possess seed-borne fungal symbionts, the epichloae, known for their bioprotective properties and especially for production of anti-insect alkaloids such as lolines. Asexual epichloae (Neotyphodium species) are primarily or entirely transmitted vertically, whereas the sexual structures (stromata) of the related Epichloa species give rise to horizontally transmissible spores (ascospores). In certain grass-Neotyphodium species symbiota, levels of lolines are extremely high and apparently limited by availability of precursor amino acids, whereas sexual epichloae generally produce much lower levels. This may reflect the inherent conflict between the vertical and horizontal transmission; although the plant and seeds may be protected by the alkaloids, the sexual cycle depends on anthomyiid flies for cross-fertilization. Given this insect role, we predicted that loline biosynthesis would be down-regulated in the stromata relative to the corresponding asymptomatic tissues (inflorescences) of the same symbiota. This prediction was substantiated, and RNA-seq and RT-qPCR analysis indicated that the loline biosynthesis genes are dramatically upregulated in asymptomatic inflorescences compared to stromata. The fundamental difference between asexual and sexual epichloae in regulation of loline alkaloid levels is in keeping with evolutionary trends for greater host control on metabolism of their vertically transmitted symbionts compared to contagious symbionts.

Gene expression profiling of the endophytic fungus Neotyphodium lolii in association with its host plant perennial ryegrass

Abstract: Endophytes of the Neotyphodium/Epichloe complex are filamentous fungi that typically form mutualistic associations with temperate grasses. The endophytes systemically colonise the intercellular spaces of their grass hosts and confer several biotic and abiotic attributes, but can also cause mammalian toxicoses. These symbioses are therefore of significant agricultural importance, and furthermore, the symbioses represent models to understand how such symbioses are established and maintained. To gain a greater understanding of the Neotyphodium lolii-perennial ryegrass (Lolium perenne) symbiosis, we have generated, sequenced and analysed four in planta expressed sequence tag libraries, enriched for genes differentially expressed during symbiosis via suppression subtractive hybridisation. Subtracted libraries were largely comprised of perennial ryegrass sequences, and comparative functional profiling of endophyte-infected ryegrass libraries with endophyte-free ryegrass libraries revealed downregulation of carbohydrate metabolism and photosynthesis during symbiosis, the latter confirming observations made in previous studies. Functional categories up regulated in the plant host in association with endophyte infection included cellular protein transport and protein synthesis and turn over.We also identified 24 N. lolii transcripts expressed during symbiosis, some of which were homologous to demonstrated pathogenicity/virulence genes, and others with proven roles in endophyte secondary metabolism. This study offers insights into biological processes underlying the N. lolii-perennial ryegrass symbiosis, and provides a list of novel candidate genes from both symbionts, which will form the basis for future investigations.

Genetic Diversity and Structure of Neotyphodium Species and Their Host Achnatherum sibiricum in a Natural Grass–Endophyte System

Abstract: Achnatherum sibiricum (Poaceae) is a perennial bunchgrass native to the Inner Mongolia Steppe of China. This grass is commonly infected by epichloe endophytes with high-infection frequencies. Previously, we identified two predominant Neotyphodium spp., N. sibiricum and N. gansuense. In the present study, genetic diversity and structure were analyzed for the two predominant Neotyphodium spp. as well as the host grass. We obtained 103 fungal isolates from five populations; 33 were identified as N. sibiricum and 61 as N. gansuense. All populations hosted both endophytic species, but genetic variation was much higher for N. gansuense than for N. sibiricum. The majority of fungal isolates were haploid, and 13% of them were heterozygous at one SSR locus, suggesting hybrid origins of those isolates. Significant linkage disequilibrium of fungal SSR loci suggested that both fungal species primarily propagate by clonal growth through plant seeds, whereas variation in genetic diversity and the presence of hybrids in both endophytic species revealed that although clonal propagation was prevalent, occasional recombination might also occur. By comparing genetic differentiation among populations, we found around 4–7-fold greater differentiation of endophyte populations than host populations, implying more restricted gene flow of endophytes than hosts. We proposed that endophyte infection of A. sibiricum might confer the host some selective advantages under certain conditions, which could help to maintain high-endophyte-infection frequencies in host populations, even when their gene flows do not match each other. Furthermore, we suggested that the same genotype of endophyte as well as host should be confirmed if the objective of the study is to know the influence of endophyte or host genotype on their symbiotic relationship, instead of just considering whether the plant is infected by an endophyte or not, since endophytes from the same host species could exhibit high levels of genetic diversity, which is likely to influence the outcome of their symbiotic relationship.

Effects of Neotyphodium endophyte on germination of Hordeum brevisubulatum under temperature and water stress conditions.

Abstract: Seed germination and seedling growth of Neotyphodium endophytE-infected(E+)and endophytE-free(E-)wild barley(Hordeum brevisubulatum)were observed under temperature and simulated drought stress conditions.Results show that germination rate and germination index of E+ seed were significantly higher than those of E-seeds(P0.05)under 10℃ and 15℃ low temperature stress and 30℃ high temperature stress.Similar results were seen under stimulated drought stress conditions of-0.6 MPa,-0.9 MPa and-1.2 MPa osmotic potential.Moreover,shoot length,root length and seedling water content of E+ seedling were significantly higher than those of E-seedling(P0.05)under stress conditions at 10℃,15℃,30℃ and-0.3 MPa～-1.2 MPa.This study shows that Neotyphodium endophyte can improve the germination rate,germination speed,seedling growth,capacity of water self-absorption of wild barley under lower and higher temperature and water stress conditions.

Contrasting infection frequencies of Neotyphodium endophyte in naturalized Italian ryegrass populations in Japanese farmlands

Abstract: Neotyphodium endophytes often confer benefits to their host grasses and may enhance invasiveness of some grasses. The knowledge of infection frequencies of endophytes among invading weed populations is necessary to understand the relationships between endophyte infection and invasiveness. Here we present data on infection frequencies of Italian ryegrass (Lolium multiflorum Lam.), an important weed in some farmlands in Japan, persisting in contrasting farmlands: a terraced paddy field and a wheat-soybean double-cropped field in the western region of Shizuoka prefecture, Japan. The terraced paddy site is a mosaic of several landscape elements such as paddy fields, levees, fallow and abandoned fields, with a high percentage of non-crop area. Rice (Oryza sativa L.) has been cultivated for more than a decade with no application of chemical fertilizers, pesticides and fungicides. The wheat-soybean field is characterized by the aggregation of large-scaled fields that were originally reconstructed paddy fields, showing a low percentage of non-crop area. Wheat and soybean have been grown as winter and summer crops, respectively, using chemical fertilizers and herbicides. We examined the presence or absence of endophytes in a total of 1200 seeds sampled from the two Italian ryegrass populations. The terraced paddy population exhibited a markedly high infection frequency (91.0%), due possibly to selective feeding of non-infected seeds by insects. In contrast, the wheat-soybean farmland population showed almost no infection (1.1%), whereas the putative source of the invasion in the proximity exhibited a relatively high infection rate (64.4%). Such a micro-scale variation in infection frequencies may be attributable to a loss in endophyte viability within the wheat-soybean field. The findings suggest that endophyte infection frequency may markedly differ among the Italian ryegrass populations even within the same region, presumably depending on the abundance of the seed-eating insects, farmland management regimes and/or environmental conditions such as soil humidity.

The potential of specialty endophyte-infected grasses for the aviation industry

Abstract: Endophytic fungi (Neotyphodium sp.) co-evolved with grasses and are known to protect plants from overgrazing by animals and insect predation by the production of toxins. This has led to the development of endophytes that are animal safe but reduce insect pests and the discovery of other chemicals that deter grazing. For airports and recreational areas turf grasses were inoculated with novel endophytes that produce insect and animal/bird avoidance behaviour. Bird strikes mostly occur during the takeoff and landing phases, so a grass that reduces the attractiveness of airports and surrounding areas to bird activity by habitat modification may be an important part of the long term solution. This paper will discuss results from trials of the selected turf type grasses containing the unique fungal endophytes and show effects on herbivorous, insectivorous and omnivorous birds that visit airfields and surrounding parklands for foraging. Preliminary data on a short versus tall grass trial using these test endophytes are presented. A large plot trial of a selected endophyte (AR601) was inoculated into a turf type tall fescue Jackal, sown at Christchurch International Airport (New Zealand) has shown a significant reduction in bird number visits in its first year. Earlier trials with caged finches (Carduelis choris) showed a 30 to 40% reduction in feeding when exposed to selected endophytic seed. Gulls (Larus dominicus) were initially consuming 60% endophyte treated feed but by the end of the trial were consuming only 30% confirming learned avoidance behaviour or post digestional feedback (PDF) to treated endophyte feed. Wild Canada geese (Branta canadensis) were used to test the effect on herbivorous birds on associations of endophyte-containing grass in a field trial where birds visited regularly. Results of this trial have shown a significant avoidance of the novel endophyte fescue and ryegrass test plants. Novel endophyte enhanced grasses for bird management at airports will soon become available in commercial quantities. This material has been established in large areas at Auckland, Hamilton and Christchurch International Airports. Data on establishment methodology, insect presence, bird behaviour, bird numbers and strike rate will be monitored over these new large areas.

Occam’s Razor Cuts Both Ways: Endophytes, Resource Allocation, Herbivory, and Mutualism: A Reply to Rudgers et al.

Abstract: Fungal endophytes and their grass hosts have attracted growing research interest as systems in which to examine the ecological and evolutionary consequences of maternally inherited symbioses. The lion’s share of research for these endophytic symbioses has been focused on Neotyphodium endophytes in three introduced agronomic grasses (but especially one, tall fescue; see Faeth and Saikkonen 2007; fig. 7.1 in Cheplick and Faeth 2009), and much of the conventional wisdom about endophyte-host interactions has been developed from these agronomic grass systems. However, accumulating studies from wild grasses suggest important species-specific differences between host grass–endophyte associations and therefore challenge concepts based on a few agronomic grass systems. My long-term study (Faeth 2009) of how asexual Neotyphodium endophytes affect resource allocation and herbivore loads in a wild grass, Arizona fescue (Festuca arizonica), is one of these, and Rudgers et al. (2010) challenge both my methods and my interpretation.

Quantification of ergovaline using HPLC and mass spectrometry in Iranian Neotyphodium infected tall fescue.

Abstract: Ergovaline, the main ergopeptine alkaloid produced in tall fescue ( Fescue arundinacea Schreb.) infected with endophyte ( Neotyphodium coenophialum Morgan- Jones & Gams), is known to cause tall fescue toxicosis. This study was conducted to examine the presence of fungal endophytes in five populations of tall fescue collected from various regions of Iran. The existence of Neotyphodium mycelia in the tissues of the samples was confirmed by microscopic examination, and the isolation was performed from leaf tissues of the hosts on potato dextrose agar. All isolates were confirmed as the Neotyphodium species by PCR, using specific primers. Mass detection and determination of ergovaline were performed by HPLC at three plant growth stages. Ergovaline was detected in all isolates, with the mean concentrations of 0.24 to 3.48 µg/g dry matter of different populations for the whole three plant growth stages. The differences in ergovaline content between plant populations and sampling time were statistically significant. This is the first report of ergovaline content in endophyte infected F escue. arundinacea from natural grasslands in Iran. Keywords: Fescue arundinacea ; Alkaloid; Ergovaline; Neotyphodium coenophialum ; toxicosis

Variable Effects of Grass-Neotyphodium Associations on Cereal Leaf Beetle (Coleoptera: Chrysomelidae) Feeding, Development and Survival

Abstract: Although cereal grains are the preferred food plants of the cereal leaf beetle, Oulema melanopus (L.), several other graminoid species are acceptable feeding hosts of larvae and adults of this chrysomelid beetle. In view of the potential for expanding the use of diverse endophytic fungi (Neotyphodium Glenn, Bacon and Hanlin) to protect forage and cereal grasses from insect pests, more information on the effect of Neotyphodium-infected (E+) grasses on the behavior and performance of the most important graminoid pests, including O. melanopus, is required. In feeding and oviposition choice experiments, adult O. melanopus fed readily on E+ and uninfected (E−) plants of wild tall fescue (Lolium arundinaceum (Schreb.) S.J. Darbyshire) and alpine timothy (Phleum alpinum L.), while exhibiting a feeding preference for E− over E+ plants of one tall fescue accession. In larval survival and development experiments, low survival on E+ plants of alpine timothy and one tall fescue accession (averaged 3.75 - 12.5%) was n...

Inhibitory effect of an endophytic fungus, Neotyphodium lolii, on the feeding and survival of Ostrinia furnacalis (Guenee) (Lepidoptera: Pyralidae) and Sesamia inferens (Walker) (Lepidoptera: Noctuidae) on infected Lolium perenne.

Abstract: To examine the feasibility of using endophytic fungi (/endophyte) as biological control agents against insect pests of host plants, the effect of Neotyphodium lolii, an endophyte living in perennial ryegrass, Lolium perenne L., was studied using two species of caterpillars: the Oriental corn borer, Ostrinia furnacalis (Guenee) (Lepidoptera: Pyralidae) and the pink borer, Sesamia inferens (Walker) (Lepidoptera: Noctuidae). Choice and no-choice feeding tests using endophyte-infected and endophyte-free clonal L. perenne indicate that endophyte-infected L. perenne have excellent resistance to O. furnacalis and S. inferens. Larvae of O. furnacalis significantly preferred endophyte-free to endophyte-infected grass. The ratio of surviving insects rapidly declined on infected grass and the survival curve on infected grass was similar to that of larvae of the no-food control. A similar trend occurred with S. inferens. These results indicate that N. lolii-infected L. perenne contains strong deterrent or toxic effects that affect O. furnacalis and S. inferens feeding and survival.

Epichloë Endophytes: Models of an Ecological Strategy

Abstract: This chapter considers our current understanding of the epichloae, for which the recently sequenced Epichloe festucae is considered a model. The epichloae are in the family Clavicipitaceae within the order Hypocreales. While it was not the first recognition of an epichloe endophyte, the discovery of an introduced tall fescue population by University of Kentucky agronomists in the early 1930s led to the development of the (in)famously popular cultivar Kentucky-31. A flourish of studies comparing endophyte-infected (E+) and endophyte-free (E-) conspecific grasses in the 1980s and 1990s established a list of host fitness enhancements attributable to the endophyte: herbivore resistance, disease resistance, competitive ability, drought tolerance, heat tolerance, and tolerance to nutrient deficits. Researchers conducted a study to determine and compare the impacts of E+ and E- tall fescue on a natural grass community. The implications of this study reveal the concern that when introduced symbiota with pronounced fitness enhancements become established in nature, they run the risk of dominating communities and driving out some native plant species. While much of the understanding of ergot alkaloid biosynthesis has come from the characterization of the genes in the Claviceps spp., disruption and characterization of key pathway genes such as dmaW, lpsA, and lpsB have also been performed for epichloe endophytes. Most of the Epichloe and Neotyphodium endophytes screened to date are able to synthesize the alkaloid peramine.