Acremonium Coenophialum Research Articles

GC-MS Analysis of extract for Endophytic fungus Acremonium coenophialum and its Antimicrobial and Antidiabetic

The aim of the present work was to study antimicrobial and antidiabetic activities of the fungal extract of endophytic fungus Acremonium coenophialum isolated from medicinal plant Myrtus communis was evaluated. The fungal extract was carried out by Ethyl acetate solvent. Column Chromatography, Thin Layer Chromatography (TLC) and Gas chromatography-mass spectrometry (GC-MSS) were used to determine the chemical composition of fungal extract from endophytic fungus A. coenophialum. As a result, a total of nineteen compounds of Fungal extract were demonstrated for antimicrobial activity against seven Gram-Positive Bacteria named Staphylococcus aureus, S. epidermidis, Streptococcus Pneumoniae, Strep. pyogenes, Enterococcus faecalis, Bacillus cereus and B. subtilis which range between (10.0-17.0) mm against seven Gram-Negative Bacteria namely; Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, Klebsiella pneumoniae, Morganella morganii, Serratia sp. and Proteus vulgaris which range between (10.0-18.0) mm and against both yeasts test was (10.0) mm. Minimum inhibitory concentrations were in the range between (25.0-100), (50-100)µg/ml and (100)µg/ml against Gram-Positive bacteria, Gram-Negative and yeasts test respectively. Minimal bactericidal concentrations ranged from (50-100)µg/ml and (100-200)µg/ ml against Gram-Positive bacteria and Gram-Negative bacteria respectively and minimal fungicidal concentrations (200)µg/ml against both yeasts test. The fungal extract also exhibited antidiabetic potential by inhibition of a-amylase activity. The activity was found to be similar to that of acarbose.

Economic evaluation of genetic markers for cow-calf operations differentiated by forage type and breed

When selecting breeding stock, the use of genetic marker information in beef cattle (Bos taurus L., and Bos indicus L.) is expected to enhance herd performance and thereby producer returns. Cattle performance data from experimental trials, tracking the single nucleotide polymorphism (SNP) P450 C994G and HSP70 CDS G2033C genotypic distributions in Angus (AA; Bos taurus), Brahman (BB; Bos indicus), and their reciprocal cross (RC) cows were investigated to determine economic performance differences when grazing endophyte infected tall fescue [Lolium arundinaceum (=Festuca arundinacea)] compared to Bermudagrass (BG; Cynodon dactylon L.) pastures. Since open cows were not culled, the study provides unique lifetime data on cow-calf breeding failure rates. These data are essential for economic comparisons of spring calving herds that were either exposed to fungal endophyte [Epichloë coenophiala (=Neotyphodium coenophialum=Acremonium coenophialum)] infected tall fescue grazing and hay (E+) or not (BG). The Forage and Cattle Analysis and Planning (FORCAP) decision support software was used to assess impact on profitability of birth weight, weaning weight, and breeding failure rate differences across treatment. Results showed that added SNP marker information did little to separate animal performance. A neural network approach also was used to assess the impact of genetic marker information to predict economic performance. Using either gene SNP, less than 5% of variation in economic returns was affected by genetic information, with the largest driver of profitability being breeding failure rate. Using the two genetic markers of this study to predict breeding failure rate showed little evidence to suggest that breeding decisions could be improved using genetic marker information. With more data, this conclusion may well change as observed least square mean differences by SNP were larger than the cost of obtaining the information but not statistically significant.

The Effects of Endophyte-Infected KY 31 Tall Fescue Seed on Northern Bobwhite Reproduction

We assessed the impact of feeding an endophyte-free, endophyte-infected (Acremonium coenophialum), KY 31 tall fescue (Festuca arundinacea Schreb.) and a control diet on northern bobwhite (Colinus virginianus) reproduction. The birds consumed significantly more of the tall fescue diets compared to the control diet. There was no difference in female body weights at the end of the experiment. Male birds lost significantly more weight on the tall fescue diets than the control diet. The birds were in positive nutritional balances on all diets. There were no treatment effects on egg production, fertility, embryo mortality, hatch ability, or number of chicks per hen. Significantly more birds died eating endophyte-infected tall fescue seed compared to endophyte-free and control diets. These results indicate that tall fescue does not affect quail reproduction as indicated by previous authors. However, the endophyte does affect the weight gain of male birds and caused high mortality in these birds. We propose the alkaloids created by the endophyte caused a swelling of the cloaca which elicited a behavioral response in the birds causing them to become cannibalistic. These data support the idea that tall fescue does not provide quality nutritional habitat for northern bobwhite.

Mycotoxicoses of ruminants and horses

In the current study, mycotoxicoses of ruminants and horses are reviewed, with an emphasis on the occurrence of these diseases in South America. The main mycotoxicoses observed in grazing cattle include intoxications by indole-diterpenoid mycotoxins (Paspalum spp. contaminated by Claviceps paspali, Lolium perenne infected by Neotyphodium lolii, Cynodon dactylon infected by Claviceps cynodontis, and Poa huecu), gangrenous ergotism and dysthermic syndrome (hyperthermia) caused by Festuca arundinacea (syn. Festuca elatior) infected by Neotyphodium coenophialum (syn. Acremonium coenophialum), and photosensitization in pastures contaminated by toxigenic Pithomyces chartarum. Other mycotoxicoses in grazing cattle include slaframine toxicity in clover pastures infected by Rhizoctonia leguminicola and diplodiosis in cattle grazing in corn stubbles. The mycotoxicoses caused by contaminated concentrated food or byproducts in cattle include poisoning by toxins of Aspergillus clavatus, which contaminate barley or sugar beetroot by-products, gangrenous ergotism or dysthermic syndrome caused by wheat bran or wheat screenings contaminated with Claviceps purpurea, and acute respiratory distress caused by damaged sweet potatoes (Ipomoea batatas). The main mycotoxicosis of horses is leukoencephalomalacia caused by the fumonisins B1 and B2 produced by Fusarium spp. Poisoning by C. purpurea and F. elatior infected by N. coenophialum has also been reported as a cause of agalactia and neonatal mortality in mares. Slaframine toxicosis caused by the ingestion of alfalfa hay contaminated by R. leguminicola has also been reported in horses.

Trigonella foenum-graecum (fenugreek)-mediated suppression of meloidogyne javanica in Mungbean

Soil amendments with powered seeds of Trigonella foenum graecum (fenugreek) caused soil suppressiveness against Meloidogyne javanica. Decomposed seeds of fenugreek caused marked reduction in nematode population densities and subsequent root-knot development as compared to the aqueous extract of the seeds, indicating that some indirect factors are involved in the suppression of root-knot nematode. Both decomposed seeds and aqueous extracts enhanced plant height and fresh weights of shoot, whereas root growth remained uninfluenced. Changes in fungal communities associated with nematode control were studied by comparing population numbers of fungi in the soil and in internal root tissues (endorhiza) in non-amended and fenugreek-amended soils. Acremonium coenophialum, Chaetomium globosum, Fusarium solani, Macrophomina phaseolina and Rhizoctonia solani were found to colonize inner root tissues of mungbean. A. coenophialum, C. globosum and F. solani were isolated in a relatively higher frequency from roots growing in the amended soils, while M. phaseolina and R. solani colonized greatly in roots growing in non-amended soil. Of the fungi isolated from soils, Penicillium brefaldianum caused maximum juvenile mortality, whereas F. solani caused greatest inhibition of egg hatch.

SULFUR SOURCE AND PLACEMENT FOR NEWLY ESTABLISHED ENDOPHYTE-FREE TALL FESCUE11

Previous research indicated that tall fescue (Festuca arundinacea Schreb.) may respond to sulfur (S) fertilization. However, data are limited concerning S management options to improve yield and quality of newly-established, endophyte-free tall fescue. Thus, a field study was conducted from 1989 to 1991 to determine the effects of S source (ammonium thiosulfate [ATS] and ammonium sulfate [AS]); rate (17 and 34 kg S ha−1); and placement (broadcast, dribble [surface band], and knife [subsurface band]) on yield and quality of a newly-established, endophyte [Neotyphodium coenophialum (Morgan-Jones and W. Gams) Glenn, Bacon, Price & Hanlin; syn. Acremonium coenophialum Morgan-Jones and W. Gams]-free, tall fescue. Compared to a no-fertilizer control, adding N alone more than tripled hay production to 6.09 Mg ha−1, but the addition of fertilizer S had little effect on early-season production and only a 6% increase in later hay yields with ATS. Sulfur fertilization increased tissue S concentration and lowered N/S ratios. Increasing the S rate from 17 to 34 kg ha−1 resulted in a small increase in S concentration and decrease in N/S ratio. Correlation analyses suggested that increasing S concentrations may reduce neutral-detergent fiber content and improve in vitro dry matter digestibility early in the season but not at hay harvest. Fescue sampled to simulate grazing in early spring yielded less but was higher in N/S ratios when S was knifed rather than surface applied. At hay harvest, knifing increased yield more than 10% and increased N concentration by 10 to 20% compared to surface application methods but had no effect on in vitro dry matter digestibility. 1 Contribution No. 00-233-J, Kansas Agric. Exp. Stn. Research partially supported by grant funds from the Fluid Fertilizer Foundation, Kerley Ag, Inc., The Sulphur Institute, and Allied-Signal, Inc.

Fungal Endophyte Effects on Production of Legumes in Association with Tall Fescue

The fungal endophyte, Neotyphodium coenophialum (Morgan‐Jones & W. Gams) Glenn, Bacon & Hanlin (syn. Acremonium coenophialum Morgan‐Jones & W. Gams) is generally considered to enhance the competitive ability of tall fescue (Festuca arundinacea Schreb.) with legumes, but substantiating field data are limited. Our objectives were to determine if endophyte infection of tall fescue affects stand density and forage production of (i) red clover (Trifolium pratense L.), ladino clover (T. repens L.), and alfalfa (Medicago sativa L.) harvested at 3‐wk intervals and (ii) alfalfa at low and high seeding rates harvested at 3‐wk and 9‐wk intervals. The first study compared alfalfa, red clover, and ladino clover in association with ‘Jesup’ E+ (endophyte‐infected) and E− (endophyte‐free) tall fescue, harvested at 3‐wk intervals for 3 yr. The second study had alfalfa broadcast planted at 11.2 and 22.4 kg ha−1 with E+ and E− tall fescue planted broadcast at 11.2 and 22.4 kg ha−1 or in rows at 22.4 kg ha−1. This was harvested at 3‐wk intervals for 3 yr, then at 5‐wk intervals for 1 yr. In the first study, clovers and alfalfa cut at 3‐wk intervals for 3 yr had similar (P > 0.05) legume yields when grown with both E+ and E− tall fescue. In the second study harvested at 3‐wk intervals, E+ tall fescue adversely affected (P < 0.05) the associated alfalfa the second year, and by the third year the yield of alfalfa planted at 22.4 kg ha−1 in mixture with E+ tall fescue was only 71% of alfalfa with E− tall fescue (P < 0.05). Similar differences occurred the next year when cut at 5‐wk intervals. Stands of alfalfa or tall fescue after 4 yr were not affected (P > 0.05) by endophyte. The results suggest that endophyte infection of tall fescue increases competition with legumes, but it may be modified by seeding rates or grass sod density.

Population Differentiation, Spatial Variation, and Sampling of Tall Fescue under Grazing

Tall fescue [Festuca arundinacea Schreb.] is the most important cool‐season perennial forage grass in Alabama and the southeastern USA. Genetic variation is essential for breeding improved cultivars, and understanding factors influencing genetic variability in pastures is important if material from existing pastures is to be used in a breeding program. This study was conducted to determine the extent of differentiation for agronomic traits in pastures grazed long‐term and to investigate possible spatial variation and its effect on sampling. Three populations from permanent pasture treatments of the USDA SARE cropping system trial in Virginia were sampled: (i) pure tall fescue fertilized with N, stocked continuously (Fescue + N); (ii) tall fescue–alfalfa (Medicago sativa L.) mixture used as hay and pasture (Fescue + alfalfa); and (iii) tall fescue–red clover (Trifolium pratense L.) mixture used as hay and pasture (Fescue + red clover). The tall fescue cultivar was endophyte‐free Ky 31 [fescue endophyte: Neotyphodium coenophialum; syn. Acremonium coenophialum]. Plants from these paddocks were established in central Alabama in 1995. Original seed from the SARE trial were also germinated for establishing the original population. Ex situ evaluation was conducted in Alabama (1995–1997). Compared with plants derived from the original seed lot, plants derived from pastures under grazing had significantly earlier maturity, higher dry matter (DM) yield per plant, and larger plant diameter, indicating population differentiation in response to grazing. No significant differences were observed among populations with different pasture management treatments. Statistical and graphical analysis of spatial variation of agronomic traits showed no spatial relationships in any of the six sampled paddocks. Bootstrap estimates of minimum and maximum values indicated that 25 individuals per paddock captured most of the phenotypic variation within each paddock. A random walk approach covering the entire unit being sampled seems therefore to be an appropriate strategy for sampling similar pastures to obtain base material for a breeding program.

Effect of Interseeding Legumes into Endophyte-Infected Tall Fescue Pastures on Forage Production and Steer Performance

Grazing and subsequent finishing performances of steers (Bos taurus) (n=135) that grazed high-endophyte [Neotyphodium coenophialum Glen, Bacon, Price, and Hanlin (formerly Acremonium coenophialum)] tall fescue (Festuca arundinacea Shreb.) pastures interseeded with lespedeza (Lespedeza stipulacea Maxim.), ladino clover (Trifolium repens L.), or red clover (Trifolium pratense L.) were evaluated during 1995, 1996, and 1997. Nine 5-acre established pastures of Kentucky 31' tall fescue with approximately 70% endophyte infection were used in a randomized complete block design containing three replications of each legume treatment. Pastures were seeded with legumes each year in late winter, and steers grazed continuously from early spring to mid-fall. At the end of the grazing phase, steers were finished for slaughter. Legume cover, available forage dry matter, grazing and subsequent feedlot performances of steers, and carcass parameters were measured. Total available forage dry matter was similar among legume treatments. A significant (P 0.05) among legume treatments in 1995 and 1996. In 1997, steers grazing ladino clover pastures gained 36% more (P< 0.01) and 28% more (P < 0.01) than those grazing lespedeza and red clover pastures, respectively. Gains by steers grazing red clover and lespedeza pastures were similar. Legume treatment during the grazing phase had no effects on subsequent finishing performance. Total gains (grazing + finishing) were similar among legume treatments in 1995 and 1996; however, in 1997, steers that grazed ladino clover had higher (P < 0.01) overall gains than those that grazed red clover or lespedeza.

Impact of Consuming Tall Fescue Leaves with the Endophytic Fungus, Acremonium coenophialum, on Meadow Voles

Most of the 14 million hectares of pastures of tall fescue ( Festuca arundinacea ) planted in the United States are infected with the endophytic fungus, Acremonium coenophialum . I examined if grazing infected plants had an adverse impact on meadow voles ( Microtus pennsylvanicus ). Captive voles fed leaves from infected fescue plants (fungus-fed voles) gave birth and weaned as many offspring as voles fed leaves from uninfected plants of the same genotype of tall fescue (control voles). Mass and body temperatures of fungus-fed and control voles did not differ. When maintained at 21°C, mortality rates were similar, but when ambient temperatures were increased to 31°C, fungus-fed voles had significantly higher mortality rates than control voles. Naive voles did not discriminate between infected and uninfected leaves, but after a diet of fescue, voles preferred uninfected leaves.

Effects of endophyte consumption on food intake, growth, and reproduction in prairie voles

Grasses infected with fungal endophytes are known to deter herbivores. Athough ingestion of infected plant tissues has detrimental effects on insects, birds, domestic livestock, and laboratory rodents, little is known about the consequences of endophyte consumption for wild rodent consumers. This multigenerational study investigated how consumption of tall fescue (Festuca arundinacea) seeds infected with the endophytic fungus Acremonium coenophialum affects prairie voles (Microtus ochrogaster). Breeding pairs were fed one of three base diets: laboratory rodent chow (C; control diet), 50% uninfected tall fescue seeds plus 50% chow (E-), or 50% endophyte-infected seeds plus 50% chow (E+). In the first generation, the E+ diet suppressed food and water intake, growth rates, and reproductive success, so no voles fed on the E+ diet could be followed in the second generation. In general, voles of the two generations performed similarly on the C and E- diets. Our findings show that prairie voles are sensitive to the presence of endophytes, or associated alkaloids, in their diets, and suggest that free-ranging voles avoid consuming endophyte-infected plant tissues if other foods are available.

Oral and parenteral vaccination of mice with protein-ergotamine conjugates and evaluation of protection against fescue toxicosis

Acremonium coenophialum produces ergopeptide alkaloids in tall fescue ( Festuca arundinacea Schreb.). These ergot alkaloids decrease serum alkaline phosphatase (ALP) activity, serum cholesterol and prolactin concentrations, as well as average daily gains (ADG) in cattle. The objective of this study was to evaluate the protection of anti-ergotamine antibodies induced by either oral or parenteral vaccination with protein-ergotamine conjugates or passive vaccination with anti-ergovaline, monoclonal antibodies in a murine model of fescue toxicosis. Ergotamine (EG) was conjugated to bovine serum albumin (BSA) and cholera toxin subunit B (CTB) by the Mannich reaction. Mice were blocked based on weight and randomly allocated into five groups of 10 mice each. Treatment groups were as follows: (1) group vaccinated intraperitoneally (ip) with a BSA–EG conjugate and fed an endophyte-infected (EI) fescue diet (BSA–EG group); (2) group orally vaccinated with a CTB–EG conjugate mixed with free cholera toxin (CT) and fed an EI fescue diet (CTB–EG group); (3) nonvaccinated group fed an EI fescue diet (EI group); (4) group passively vaccinated with anti-ergovaline, monoclonal antibodies and fed an EI fescue diet (MoAB group); and (5) nonvaccinated group fed an endophyte-free (EF) fescue diet (EF group). The EI diet contained 1.5 ppm of Ergovaline (EV), whereas no EV was detected in the EF diet. Respective diets were similar upon nutritional analysis. Unvaccinated mice in the EI group exhibited features of fescue toxicosis as indicated by decreased serum ALP activity and cholesterol, and decreased weight gain as compared to mice in the EF group. Antibodies against EG and EV were present in sera of mice in the BSA–EG and MoAB groups, respectively. Mice orally vaccinated with the CTB–EG conjugate developed secretory IgA (sIgA) antibodies and short-lived, systemic IgG responses against EG. Weight gains were increased in the BSA–EG and CTB–EG groups and tended to be increased in the MoAB group vs. the unvaccinated EI group. Serum ALP activity was decreased in the BSA–EG and MoAB groups as compared to the EF group. Serum ALP activity was further decreased in the BSA–EG vaccinated group as compared to the EI group. Cholesterol concentrations were decreased in the EI, BSA–EG and MoAB groups as compared to the EF group. Prolactin concentrations were similar in all groups.

Analysis of Ergot Alkaloids in Endophyte-Infected Tall Fescue by Liquid Chromatography/Electrospray Ionization Mass Spectrometry

Previous investigators have identified a number of ergot alkaloids (EAs) in tall fescue (Festuca arundinacea Schreb.) infected by the endophytic fungus, Neotyphoidium coenophialum [(Morgan-Jones & W. Gams) Glenn, Bacon & Hanlin comb. nov.]. Their results, however, may have been confounded by the presence of the related parasitic ergot fungus (Claviceps purpurea [Fr.:Fr.] Tul.), which also produces EAs. Semipreparative HPLC was used to separate fractions giving a high fluorescence response in a sample of endophyte-infected (EI) tall fescue seeds, carefully examined to eliminate the possibility of Claviceps infection. Analytical high-performance liquid chromatography (HPLC) and LC/electrospray ionization mass spectrometry (ESI-MS) were used to identify EAs after isolation. Clearly identified in the spectra were ergine, ergovaline, ergosine, ergonine, and previously undescribed EAs, didehydroergovaline and aci-ergovaline, including their epimers. Several additional EAs may have been present, but structures could not be confirmed by their spectra. Not found in the isolated fractions were ergonovine, ergotamine, or lysergylmethylcarbinolamide. The developed HPLC method was used to determine the alkaloids in plants, culms, and seeds of EI tall fescue. Keywords: Neotyphodium coenophialum; Acremonium coenophialum; Festuca arundinacea, ergovaline

Improved Method of Analysis for Ergovaline in Tall Fescue by High-Performance Liquid Chromatography

A rapid HPLC method of analysis for ergovaline in tall fescue plants is presented; it offers the advantages of utilizing readily available materials that are safer to use than those in previous methods. In addition, the sample preparation and chromatographic method allow for the detection and quantification of both C-8 epimers of the target alkaloid. Inclusion of the epimer in the analysis procedure provides a more accurate method of determining total ergovaline in plant materials. Keywords: Festuca arundinacea; Neotyphodium coenophialum; Acremonium coenophialum

PCR assay based on a microsatellite-containing locus for detection and quantification of Epichloë endophytes in grass tissue.

A PCR assay which allows detection and quantification of Epichloë endophytes in tissues of the grass Bromus erectus is described. PCR with specific primers flanking a microsatellite-containing locus (MS primers) amplified fragments 300 to 400 bp in length from as little as 1.0 pg of fungal genomic DNA in 100 ng of DNA from infected plant material. When annealing temperatures were optimized, all Epichloë and Acremonium strains tested, representing many of the known taxonomic groups, yielded an amplification product, indicating that the MS primers may be useful for in planta detection of a variety of related species, including agronomically important Acremonium coenophialum and Acremonium lolii. No fragments were generated from DNA isolates from uninfected plant material or from unrelated fungi isolated from B. erectus. For diagnostic applications, a B. erectus-specific primer pair was designed for use in multiplex PCR to allow simultaneous amplification of plant and fungal DNA sequences, providing an internal control for PCR failure caused by inhibitory plant compounds present in DNA extracts. For quantitative applications, a heterologous control template in primer binding sites complementary to the MS primers was constructed for use in competitive PCR, allowing direct quantification of Epichloë in plant DNA extracts. The fungal DNA present in infected leaves of B. erectus between 1 and 20 pg per 100 ng of leaf DNA, but the amounts of fungal DNA present in the sheath and blade of a given leaf were correlated, indicating that the degree of infection varied between plant individuals but that leaves were colonized in a uniform way.

Effect of a Fungal Endophyte on the Growth and Survival of Two Euplectrus parasitoids

Presence of the endophytic fungus, Acremonium coenophialum, within tall fescue (Festuca arundinacea) deters many vertebrate and invertebrate herbivores, apparently because of alkaloids produced by the grass-fungus symbiotum. In one set of experiments we tested if A. coenophialum alters the growth and survival of two parasitoids of an insect herbivore feeding on tall fescue. We fed fall armyworm [Spodoptera fruigiperda (Lepidoptera: Noctuidae)] larvae tall fescue either infected or lacking its endophytic fungus and then allowed the parasitoids, Euplectrus comstockii and Euplectrus plathypenae (Hymenoptera: Eulophidae), to parasitize larvae. We found the presence of endophyte-infected plants in the diet of fall armyworm had a negative impact on the pupal mass of parasitoids. In contrast, developmental rate of the parasitoids was generally not affected by the fungal endophyte. Survival of neither parasitoid to the adult stage was reduced by the presence of endophyte-infected grass in the diet of fall armyworm. We also tested if effects of the fungus on E. comstockii were due to the specific alkaloids, N-acetyl and N-formyl loline, that are produced by the grass-fungus symbiotum. When added to artificial diets of fall armyworm, both lolines resulted in reduced survival of parasitoids. Overall, we found the fungus had a moderate negative impact on two natural enemies that mirrors some of the effects the fungus has on insect herbivores and that may be mediated, at least in part, by alkaloids associated with the fungus. We discuss implications of our work for the hypothesis that endophytes defend their host grasses from herbivores.

Tall Fescue Response to Clipping and Competition with No‐Till Seeded Alfalfa as Affected by Fungal Endophyte

AbstractTall fescue (Festuca arundinacea Schreb.) is generally less productive, persistent, and competitive under stress after removal of its fungal endophyte, Neotyphodium coenophialum (Morgan‐Jones &amp; W. Gams) Glenn, Bacon &amp; Hanlin (syn. Acremonium coenophialum Morgan‐ Jones &amp; W. Gams). Our objectives were to compare endophyteinfected (E + ) and endophyte‐free (E −) tall fescue for (i) forage yield and tiller response at different cutting frequencies and heights and (ii) competition with no‐till seeded alfalfa (Medicago sativa L.). Factorialized combinations of 3‐wk and hay‐stage harvest intervals with clipping heights of 3.8 cm (low) and 7.6 cm (high) were used with E + and E − tall fescue in a 4‐yr study. ‘Alfagraze’ alfalfa was no‐till seeded into E + and E − ‘Kentucky 31’ tall fescue, E − ‘AU Triumph’ tall fescue, orchardgrass (Dactylis glomerata L.), reed canarygrass (Phalaris arundinacea L.), and Kentucky bluegrass (Poa pratensis L.) in each of 3 yr. Forage yield of E + and E − Kentucky 31 was similar (P &gt; 0.05) within a cutting treatment. When cut at 3‐wk intervals, a low as compared with a high clipping height had no effect (P &gt; 0.05) on total forage yield of E + Kentucky 31 tall fescue, but forage yield of E − Kentucky 31 and E − AU Triumph were reduced by 23 and 28%, respectively, in the fourth year. Both E + and E − tall fescue cut every 3 wk during a dry, hot summer at a low clipping height had autumn forage yields only 20 to 25% of that at a high clipping height. Tiller populations declined more on AU Triumph than E − Kentucky 31 in response to cutting. Cutting height had a minor effect on yield with hay‐stage harvest. Endophyte infection had no effect on stands or forage yield of no‐till seeded alfalfa. Alfalfa forage yields were lower with tall fescue than with the other grass species. AU Triumph, a winter‐productive tall fescue, was the grass most competitive with alfalfa.

Growth and water relations of field‐grown tall fescue as influenced by drought and endophyte

AbstractField plots were established in autumn 1992 in which endophyte [Neotyphodium coenophialum Glenn. Bacon, Price and Hanlin (formerly Acremonium coenophialum)]‐infected (E+) and endophyte‐free (E−) isolines of three tall fescue [Festuca arundinacea Schreb.) genotypes were planted. Plants were subjected to three water‐withholding periods in 1993 and one in 1994, or were kept well watered throughout the experiment. There were no consistent endophyte effects for leaf elongation, tiller density or dry weight per tiller. There were genotype X endophyte interactions (P&lt;001) for tiller density and shoot dry weight per area and genotype X water X endophyte interactions (P&lt;005) for cumulative leaf elongation in 1993. These interactions indicated the highly specific effect of host genotype‐endophyte association on the expression of plant growth. Leaf rolling in the stressed treatments was more severe in E− than in E+ plants in 1993, but there were no differences in 1994, and stomatal conductance tended to be lower in E− than in E+ plants in 1993. Fractional water content of the lower 3 cm of the youngest fully developed leaf sheath was usually greater, and never less, in E+ than in E− plants. The leaf rolling and stomatal conductance results suggest that E− plants were more severely stressed in the summer after planting. Thus, the endophyte may induce greater water retention in the leaf sheath and therefore better protect the internal growing zone from lethal desiccation.

Performance of endophyte-free and endophyte-infected tall fescue seedlings in soil infested withCochliobolus sativus

Responses of tall fescue (Festuca arundinacea) seedlings free of or infected with Acremonium coenophialum were determined when exposed to soil infested with Cochliobolus sativus. In a greenhouse pot experiment, germinated seeds of AU Triumph and Kentucky 31 (KY 31) tall fescue were covered with a soil mixture containing corncob grits infested with C. sativus. Emergence, establishment of seedlings, and growth of leaves and shoots were determined weekly for 6 wk. Emergence and growth of KY 31 seedlings were greater than for those of AU Triumph. Plant stand, height, and shoot fresh weight were significantly reduced by C. sativus after 6 wk in plants free of or infected with A. coenophialum compared to noninoculated plants. There was no significant difference in growth parameters between plants free of or infected with A. coenophialum. The data support a neutral interaction between the endophyte and the pathogen.

Allelopathic Effects on Germination and Seedling Growth of Clovers by Endophyte‐Free and ‐Infected Tall Fescue

Reports of allelopathy by tall fescue (Festucarundinacea Schreb.) on Trifolium species are inconsistent. Many tall fescue plants are infected with a fungal endophyte (Acremonium coenophialum Morgan‐Jones &amp; Gams), which may account for some of the inconsistencies. My objective was to investigate the allelopathic effect of extracts of endophyte‐free (TF − E) and ‐infected (TF + E) tall fescue seeds the seed germination and seedling growth (shoot, root, and root‐hair length and root‐hair density) of five Trifolium species (ball clover, T. nigrescens Viv.; crimson clover, T. incarnatum L.; red clover, T. pratense L.; subterranean clover, T. subterraneum L.; and white clover, T. repens L.). Extracts were prepared by passing 50 g of seed through a pulverizing mill, soaking the milled seed in 500 mL of deionized water, filtering, and sterilizing the solution. Differences among allelopathic effects for seed germination were attributed to legume species. Although the presence of fungal endophyte had no effect on seed germination, germination of ball, crimson, and red clover seed was significantly reduced in extracts of tall fescue seed. Differences among allelopathic effects for shoot and root lengths were attributed to legume species. Seedling shoot length was significantly increased and root length was significantly decreased for clover seedlings grown in tall fescue extracts. Differences among allelopathic effects for root‐hair length and density were attributed to species and substrate (TF − E vs. TF + E) differences. There was a 34% reduction in root‐hair length and a 45% reduction in root‐hair density for clover seedlings grown in seed extracts compared with seedlings grown in water. Seed germination and seedling shoot and root lengths inadequately expressed the subtle allelopathic effects of the fungal endophyte. Micromorphological characters, such as root hairs, may be more sensitive in detecting allelopathic effects.