Endophyte Acremonium Research Articles

Metabolic profiling for the discovery of two rare fusidane-type heterodimers from the fungal endophyte Acremonium pilosum F47

In our process of studying fusidane-type antibiotics, metabolomics-guided chemical investigation on the endophytic Acremonium pilosum F47 led to the isolation of two unique heterodimers, acremonidiols B and C (1 and 2) consisting of a fusidane-type triterpenoid motif and a steroid unit. Four biosynthetically related known natural products including fusidic acid (FA, 3), as well as ergosterol derivatives (4–6) were also obtained. Their structures were determined by the analyses of ESI-HRMS and NMR data. Compounds 1 and 2, as hybrid molecules comprising the fusidane triterpenoid and steroid, are rare in nature. Compared with the clinically used antibiotic FA (3), new compounds 1 and 2 showed no obvious antibiotic activity, indicating the importance of free C-21 carboxyl group for antibacterial activity.

Isolation, Morphological And Biochemical Identification Of Endophytic Fungi From Moringa oleifera And Its Antimicrobial Potential

The present study was aimed at isolating endophytic fungi from the leaves of M. oleifera and analyzing its antimicrobial potential. In this study, the fungal endophyte Acremonium sp. was isolated identified through morphological and biochemical analysis. In IAA the strain produced 55.27 ± 3.00 μgml-1 IAA without exogenous tryptophan application (control) in the culture medium. The addition of 1mgml-1 tryptophan to the culture medium increased the IAA production to 76 ± 2.6 μgml-1 The production of siderophore was performed in the absence and presence of an iron source in the medium. The strain was cultured in the minimal media supplemented with different Fe(III) citrate concentrations, i.e., 0 μM, 0.25 μM, 2.0 μM, and 4.0 μM. The isolated fungi showed high siderophore production when cultured in a medium without Fe(III) citrate. Siderophore production found to be 40.00 ± 0.4 (psu) in the culture medium without the addition of Fe(III) citrate.. Siderophore production was slightly reduced , i.e., 33 ± 0.3 (psu) at 0.25 μM Fe(III) citrate in the culture medium. However, a significant reduction in the production of the siderophore was observed when Fe (III) citrate content was raised to 2.0 μM and 4.0 μM. In case of bacterial strains it was observed that maximum activity was observed against P. aeruginosa at 80 µg/ml (IZ-20mm) while minimum at 20 µg/ml against E. coli (10mm) but at 40 and 60 µg/ml activity was at par (IZ-14mm) while S. aureus was found to be partially resistant. In case of antifungal it was observed that when extract of PD 20 was tested maximum activity was observed at 80 µg/ml against T. reesei (IZ-22mm) while C. albicans was found to be partially resistant as initially no activity was observed against it. Against P. funiculosum no activity was observed at 20 µg/ml but with increase dose level activity increased.Therefore, we conclude that the isolated Acremonium sp. should be further investigated before utilization as a biocontrol agent and plant growth stimulator

Characterization of Endophytic Fungi, Acremonium sp., from Lilium davidii and Analysis of Its Antifungal and Plant Growth-Promoting Effects.

The present study was aimed at isolating endophytic fungi from the Asian culinary and medicinal plant Lilium davidii and analyzing its antifungal and plant growth-promoting effects. In this study, the fungal endophyte Acremonium sp. Ld-03 was isolated from the bulbs of L. davidii and identified through morphological and molecular analysis. The molecular and morphological analysis confirmed the endophytic fungal strain as Acremonium sp. Ld-03. Antifungal effects of Ld-03 were observed against Fusarium oxysporum, Botrytis cinerea, Botryosphaeria dothidea, and Fusarium fujikuroi. The highest growth inhibition, i.e., 78.39 ± 4.21%, was observed for B. dothidea followed by 56.68 ± 4.38%, 43.62 ± 3.81%, and 20.12 ± 2.45% for B. cinerea, F. fujikuroi, and F. oxysporum, respectively. Analysis of the ethyl acetate fraction through UHPLC-LTQ-IT-MS/MS revealed putative secondary metabolites which included xanthurenic acid, valyl aspartic acid, gancidin W, peptides, and cyclic dipeptides such as valylarginine, cyclo-[L-(4-hydroxy-Pro)-L-leu], cyclo(Pro-Phe), and (3S,6S)-3-benzyl-6-(4-hydroxybenzyl)piperazine-2,5-dione. Other metabolites included (S)-3-(4-hydroxyphenyl)-2-((S)-pyrrolidine-2-carboxamido)propanoic acid, dibutyl phthalate (DBP), 9-octadecenamide, D-erythro-C18-Sphingosine, N-palmitoyl sphinganine, and hydroxypalmitoyl sphinganine. The strain Ld-03 showed indole acetic acid (IAA) production with or without the application of exogenous tryptophan. The IAA ranged from 53.12 ± 3.20 μg ml−1 to 167.71 ± 7.12 μg ml−1 under different tryptophan concentrations. The strain was able to produce siderophore, and its production was significantly decreased with increasing Fe(III) citrate concentrations in the medium. The endophytic fungal strain also showed production of organic acids and phosphate solubilization activity. Plant growth-promoting effects of the strain were evaluated on in vitro seedling growth of Allium tuberosum. Application of 40% culture dilution resulted in a significant increase in root and shoot length, i.e., 24.03 ± 2.71 mm and 37.27 ± 1.86 mm, respectively, compared to nontreated control plants. The fungal endophyte Ld-03 demonstrated the potential of conferring disease resistance and plant growth promotion. Therefore, we conclude that the isolated Acremonium sp. Ld-03 should be further investigated before utilization as a biocontrol agent and plant growth stimulator.

Colonization of endophyte Acremonium sp. D212 in Panax notoginseng and rice mediated by auxin and jasmonic acid.

Endophytic fungi can be beneficial to plant growth. However, the molecular mechanisms underlying colonization of Acremonium spp. remain unclear. In this study, a novel endophytic Acremonium strain was isolated from the buds of Panax notoginseng and named Acremonium sp. D212. The Acremonium sp. D212 could colonize the roots of P. notoginseng, enhance the resistance of P. notoginseng to root rot disease, and promote root growth and saponin biosynthesis in P. notoginseng. Acremonium sp. D212 could secrete indole-3-acetic acid (IAA) and jasmonic acid (JA), and inoculation with the fungus increased the endogenous levels of IAA and JA in P. notoginseng. Colonization of the Acremonium sp. D212 in the roots of the rice line Nipponbare was dependent on the concentration of methyl jasmonate (MeJA) (2-15 μmol/L) and 1-naphthalenacetic acid (NAA) (10-20 μmol/L). Moreover, the roots of the JA signaling-defective coi1-18 mutant were colonized by Acremonium sp. D212 to a lesser degree than those of the wild-type Nipponbare and miR393b-overexpressing lines, and the colonization was rescued by MeJA but not by NAA. It suggests that the cross-talk between JA signaling and the auxin biosynthetic pathway plays a crucial role in the colonization of Acremonium sp. D212 in host plants.

Bazı Antagonist Trichoderma ve Endofitik Acremonium İzolatlarının Fusarium Kök ve Kök-Boğazı Çürüklüğü Hastalıklarına Karşı Etkinliklerinin Belirlenmesi

The use of antagonist microorganisms against pathogenic organisms in organic agricultural systems was promising for biological control approach. The aim of this study was to determination of the potential biological control of some fungal isolates which characterized as endophytic and antagonistic against soil borne Fusarium culmorum (FC) and F. oxysporum f.sp. radicis lycopersici (FORL) pathogens. For this, seven isolates of endophytic Acremonium spp. that isolated from healthy wheat plants and eight isolates of antagonist Trichoderma spp., isolated from soil of organic vegetable areas, were performed as biological control agents (BCA). The agar media with hypha and mycelia of the BCAs and spore suspensions (106 spores/ml) of FC and FORL were treated for inoculation of wheat seeds and tomato seedlings. The harvested plants were statistically analyzed by some parameters (severity of crown rot disease (%DS and scale), plant lengths (cm) etc.). In conclusion, the Acremonium isolates (47.5%) were lower means of disease severity than Trichoderma isolates (74.6%) for FC and FORL assessments in wheat experiment. In tomato, the averages of disease severity between Acremonium and Trichoderma were similar while their means were lower than positive control (The Scale of DS=0.67

Identification of Acremonium isolates from grapevines and evaluation of their antagonism towards Plasmopara viticola

Some endophytic fungal genera in Vitis vinifera, including Acremonium, have been reported as antagonists of Plasmopara viticola. Endophytic Acremonium isolates from an asymptomatic grapevine cultivar Inzolia from Italy were identified by morphological features and multigene phylogenies of ITS, 18S and 28S genes, and their intra-specific genomic diversity was analyzed by RAPD analysis. Culture filtrates (CFs) obtained from Acremonium isolates were tested in vitro for their inhibitory activity against the P. viticola sporangia germination. Among 94 isolates, 68 belonged to the Acremonium persicinum and 26 to the Acremonium sclerotigenum. RAPD analysis grouped the A. persicinum isolates into 15 clusters and defined 31 different strains. The A. sclerotigenum isolates, instead, were clustered into 22 groups and represented 25 strains. All A. persicinum CFs inhibited sporangia germination of P. viticola, while not all those of A. sclerotigenum had inhibitory effect. A different degree of inhibition was observed between strains of the same species, while some strains of different species showed identical inhibitory effect. No correlation was found between RAPD groups and inhibitory activity in both Acremonium species.

Gliotoxin-producing endophytic Acremonium sp. from Zingiber officinale found antagonistic to soft rot pathogen Pythium myriotylum.

Soft rot caused by Pythium sp. is a major cause of economic loss in ginger cultivation. Endophytic fungi isolated from Zingiber officinale were screened for its activity against the soft rot pathogen Pythium myriotylum. Among the isolates screened, an endophytic fungus which was identified as Acremonium sp. showed promising activity against the phytopathogen in dual culture. The selected fungus was cultured in large scale on solid rice media and was extracted with ethyl acetate. The crude extract was subjected to column chromatography and preparative HPLC to obtain the fraction with the antifungal activity. LC-QTOF-MS/MS analysis of this fraction done using water-acetonitrile gradient identified a mass of m/z 327 (M + H) corresponding to gliotoxin with specific fragments m/z 263, 245, 227, and 111. The result was reconfirmed in negative mode ionization. Gliotoxin is the major antagonistic peptide produced by the commercially used biocontrol agent, Trichoderma sp., which shows high antagonism against Pythium sp. The gliotoxin production by the isolated endophytic Acremonium sp. of Z. officinale shows the possible natural biocontrol potential of this endophytic fungus.

Effect of grass species and fungal endophyte on soil nitrification potential

This experiment tested the impact of grass species and fungal endophyte status and strain on soil nitrification. Three C3 grass–endophyte combinations were tested: Festuca arundinacea–Neotyphodium coenophialum; F. pratensis–N. uncinatum; Lolium perenne–N. lolii, and included different strains of endophyte and endophyte-free grasses. Three C4 species— Brachiaria decumbens, Paspalum dilatatum and Pennisetum clandestinum—of unknown Acremonium endophyte status, were also tested. Plants were grown for 6 weeks without fertiliser in pots in a field soil (Mollic Psammaquent), then rhizosphere soil was sampled and incubated at 27 °C with and without (NH4)2SO4. The –N production was measured weekly. The presence of plants significantly increased the nitrification rate compared with bare soil. There were significant differences (P=0.02) among plant species. In all cases, endophyte presence increased nitrification in soil samples (P<0.001) relative to endophyte-free within a species.

Purification and characterization of arabinofuranosidase from the corn endophyte Acremonium zeae

Acremonium zeae, one of the most prevalent fungal colonists of preharvest corn, possesses a suite of hemicellulolytic activities including xylanase, xylosidase, and arabinofuranosidase. Two enzymes with arabinofuranosidase activity were purified from cell-free culture supernatants of A. zeae grown on oat spelt xylan. A 47 kDa enzyme (AF47) was optimally active at 37 °C and pH 6.0, and had a specific activity for 4-nitrophenyl-α-L-arabinofuranoside (4NPA) of 6.2 U/mg. A 30 kDa enzyme (AF30) was optimally active at 50 °C and pH 4.5, and had a specific activity for 4NPA of 12.4 U/mg. AF47 hydrolyzed 4-nitrophenyl-β-D-xylopyranoside, 4-nitrophenyl-β-D-glucopyranoside, and 4-nitrophenyl-β-D-cellobioside, as well as producing reducing sugars from corn fiber, wheat, and oat spelt arabinoxylan. AF30 had little detectable activity on the 4-nitrophenyl substrates, except for 4NPA, but activity on arabinoxylans from corn fiber, wheat, and oat spelt was at least 7-fold higher than AF47, with specific activities of 109, 358, and 153 U/mg, respectively. A combination of the two enzymes released 61 and 88% of the total arabinose from corn fiber and wheat arabinoxylans. The arabinofuranosidases produced by A. zeae may have industrial application for the enzymatic hydrolysis of recalcitrant lignocellulosic feedstocks such as corn fiber and wheat straw.

Cellulases and Hemicellulases from Endophytic Acremonium Species and Its Application on Sugarcane Bagasse Hydrolysis

The aim of this work was to have cellulase activity and hemicellulase activity screenings of endophyte Acremonium species (Acremonium zeae EA0802 and Acremonium sp. EA0810). Both fungi were cultivated in submerged culture (SC) containing L -arabinose, D -xylose, oat spelt xylan, sugarcane bagasse, or corn straw as carbon source. In solid-state fermentation, it was tested as carbon source sugarcane bagasse or corn straw. The highest FPase, endoglucanase, and xylanase activities were produced by Acremonium sp. EA0810 cultivated in SC containing sugarcane bagasse as a carbon source. The highest β-glucosidase activity was produced by Acremonium sp. EA0810 cultivated in SC using D -xylose as carbon source. A. zeae EA0802 has highest α-arabinofuranosidase and α-galactosidase activities in SC using xylan as a carbon source. FPase, endoglucanase, β-glucosidase, and xylanase from Acremonium sp. EA0810 has optimum pH and temperatures of 6.0, 55 °C; 5.0, 70 °C; 4.5, 60 °C; and 6.5, 50 °C, respectively. α-Arabinofuranosidase and α-galactosidase from A. zeae EA0802 has optimum pH and temperatures of 5.0, 60 °C and 4.5, 45 °C, respectively. It was analyzed the application of Acremonium sp. EA0810 to hydrolyze sugarcane bagasse, and it was achieved 63% of conversion into reducing sugar and 42% of conversion into glucose.

Extracellular Hemicellulolytic Enzymes from the Maize Endophyte Acremonium zeae

Microorganisms that colonize plants require a number of hydrolytic enzymes to help degrade the cell wall. The maize endophyte Acremonium zeae was surveyed for production of extracellular enzymes that hydrolyze cellulose and hemicellulose. The most prominent enzyme activity in cell-free culture medium from A. zeae NRRL 6415 was xylanase, with a specific activity of 60 U/mg from cultures grown on crude corn fiber. Zymogram analysis following SDS-PAGE indicated six functional xylanase polypeptides of the following masses: 51, 44, 34, 29, 23, and 20 kDa. Xylosidase (0.39 U/mg), arabinofuranosidase (1.2 U/mg), endoglucanase (2.3 U/mg), cellobiohydrolase (1.3 U/mg), and beta-glucosidase (0.85 U/mg) activities were also detected. Although apparently possessing a full complement of hemicellulolytic activities, cell-free culture supernatants prepared from A. zeae required an exogenously added xylosidase to release more than 90% of the xylose and 80% of the arabinose from corn cob and wheat arabinoxylans. The hydrolytic enzymes from A. zeae may be suitable for application in the bioconversion of lignocellulosic biomass into fermentable sugars.

Interaction between Acremonium byssoides and Plasmopara viticola in Vitis vinifera

Summary. The endophytic fungus Acremonium byssoides was isolated from the leaves of grapevine cv. Regina Bianca to determine whether it could act as an antagonistic endophyte of the downy mildew agent Plasmopara viticola. The occurrence of this fungus was ascertained in 34 grapevines (cultivars Regina Bianca, Catarratto and Insolia) representing all the grapevine plants in an experimental vineyard located in Sicily and which had never been treated with any fungicides. The isolation frequency of the endophytic Acremonium strains was assessed in several plant organs by means of monthly samplings over a 2-year period. The endophyte was found in all the grapevines, with higher frequencies in the cv. Regina Bianca in the buds, and in the cooler months of the year. All the strains collected from the leaves, and most of the strains from the buds of cv. Insolia were identifi ed as A. byssoides by conventional means. The presence and spatial distribution of A. byssoides was determined in asymptomatic or P. viticola-infected leaves of the grapevine cv. Insolia using an optimised staining technique and differential interferential contrast light microscopy, as well as laser scanning microscopy. A. byssoides was a natural colonizer of grapevines and actively parasitized P. viticola. Culture fi ltrates and the crude extract of A. byssoides obtained from a cv. Insolia foliar strain, completely inhibited P. viticola sporangia.

Secondary Mould Metabolites. Part 64. Acremines A—F, Novel Secondary Metabolites Produced by a Strain of an Endophytic Acremonium, Isolated from Sporangiophores of Plasmopara viticola in Grapevine Leaves.

Secondary Mould Metabolites. Part 64. Acremines A—F, Novel Secondary Metabolites Produced by a Strain of an Endophytic Acremonium, Isolated from Sporangiophores of Plasmopara viticola in Grapevine Leaves.

Acremines A–F, novel secondary metabolites produced by a strain of an endophytic Acremonium, isolated from sporangiophores of Plasmopara viticola in grapevine leaves

Six novel metabolites, acremines A–F have been isolated from agar cultures of a strain of Acremonium sp. Their structures and stereochemistry were elucidated using a combination of 13C and 1H homo and heteronuclear 2D NMR experiments and X-ray analysis. Acremines A–D inhibited the germination of sporangia of Plasmopara viticola.

A protective endophyte of maize: Acremonium zeae antibiotics inhibitory to Aspergillus flavus and Fusarium verticillioides

The maize endophyte Acremonium zeae is antagonistic to kernel rotting and mycotoxin producing fungi Aspergillus flavus and Fusarium verticillioides in cultural tests for antagonism, and interferes with A. flavus infection and aflatoxin contamination of preharvest maize kernels. Chemical studies of an organic extract from maize kernel fermentations of Acremonium zeae (NRRL 13540), which displayed significant antifungal activity against Aspergillus flavus and F. verticillioides, revealed that the metabolites accounting for this activity were two newly reported antibiotics pyrrocidines A and B. Pyrrocidines were detected in fermentation extracts for 12 NRRL cultures of Acremonium zeae isolated from maize kernels harvested in Illinois (4/4 cultures), North Carolina (5/5), Georgia (1/2) and unrecorded locations within the USA (2/2). Pyrrocidine B was detected by LCMSMS in whole symptomatic maize kernels removed at harvest from ears of a commercial hybrid that were wound-inoculated in the milk stage with A. zeae (NRRL 13540) or (NRRL 13541). The pyrrocidines were first reported from the fermentation broth of an unidentified filamentous fungus LL-Cyan426, isolated from a mixed Douglas Fir hardwood forest on Crane Island Preserve, Washington, in 1993. Pyrrocidine A exhibited potent activity against most Gram-positive bacteria, including drug-resistant strains, and was also active against the yeast Candida albicans. In an evaluation of cultural antagonism between 13 isolates of A. zeae in pairings with A. flavus (NRRL 6541) and F. verticillioides (NRRL 25457), A. zeae (NRRL 6415) and (NRRL 34556) produced the strongest reaction, inhibiting both organisms at a distance while continuing to grow through the resulting clear zone at an unchanged rate. Maximum colony diameters for A. zeae (NRRL 6415) and (NRRL 13540), on potato dextrose agar after 14 d, were attained within the range of 25-30 degrees C, with less growth recorded at 15 degrees and 37.5 degrees and no growth at 5 degrees. Potential interactions between A. zeae and other maize endophytes are considered and the significance of these interactions relative to the aflatoxin and fumonisin contamination of preharvest maize is presented. This is the first report of natural products from Acremonium zeae.

Genetic Diversity in Acremonium Endophytes Isolated from Warm-season Grasses as Revealed by RAPD Markers

Genetic diversity in Acremonium endophyte of warm-season grasses was studied using RAPD markers. Diversity levels of 60–100% were evident from all the fifteen isolates studied. This appears to be the first study on genetic variation in Acremonium endophytes of warm-season grasses.

Detection of the nematophagous fungus Verticillium chlamydosporium in nematode-infested plant roots using PCR

PCR-based methods to detect Verticillium chlamydosporium on infected plant roots were developed. Arbitrary ERIC primers and those based on rRNA genes, to identify fungi grown in pure culture, were unsuitable for DNA extracted from nematode-infested roots, because of interference by plant and nematode DNA. A novel method utilizing specific primers designed from an amplified and cloned fragment of the V. chlamydosporium β-tubulin gene was developed. Although it could not discriminate between different isolates of V. chlamydosporium, one primer set could identify the fungus on tomato roots infested with root-knot nematodes. The V. chlamydosporium β-tubulin sequence data showed close homology to sequences from plant endophytic Acremonium and Epichloe species and the saprotrophic Trichoderma viride.

Interactions between Herbivores and Endophyte-Infected Festuca rubra from the Scottish Islands of St. Kilda, Benbecula and Rum

Fungal endophytes of tall fescue, Festuca arundinacea, have been found to synthesize toxic alkaloids which function as an anti-herbivore defence. Ingestion of infected F. arundinacea causes widespread losses to the US livestock industry. We investigated whether the fungal endophyte Acremonium in the congeneric species, Festuca rubra, may be playing a similar role on four Scottish islands. Hirta, an island in the St. Kilda group, is grazed by a population of feral Soay sheep which crashes every 3-5 years with up to 60% mortality. Fungal endophytes of F. rubra were present in 65-100% of shoots. Infection frequency was positively correlated with grazing pressure. Infection was significantly lower on the neighbouring ungrazed island of Dun, supporting the hypothesis that endophytes function to deter herbivory. In contrast, on the Hebridean islands of Rum and Benbecula, there were no significant differences in endophyte infection between grazed and ungrazed populations of F. rubra. Here, infection rates were lower than on Hirta, suggesting that endophyte-host-grazer interactions were not significant. In common garden experiments with F. rubra from St. Kilda and Rum, endophyte infection resulted in higher survival rates of plants. However, there were no significant differences between infected and uninfected plants in leaf and shoot growth. Thus, while variation in infection frequencies on Hirta was most likely due to selective grazing of uninfected plants, the effect of infection status on plant survival may also have influenced these frequencies. Infected F. rubra from St. Kilda was found to be toxic and cause mortality in locust bioassays. Two additional results suggested that the fungal endophytes of F. rubra may function as an antiherbivore defence which is inducible, and could influence sheep population crashes on St. Kilda. First, the concentration of endophytic hyphae was significantly greater in infected plants from grazed patches than infected plants from adjacent ungrazed patches. This indicated a relationship between grazing pressure and endophyte concentration. Secondly, in a simulated grazing experiment with infected plants from St. Kilda, levels of the ergot alkaloid, ergovaline, in clipped plants were significantly greater than the undetectable levels in infected plants which were not clipped ('ungrazed') for 12 months.

Levels and tissue distribution of loline alkaloids in endophyte-infected Festuca pratensis

Festuca pratensis (meadow fescue) infected with the endophyte Acremonium uncinatum produces loline alkaloids (1-aminopyrrolizidines) that are not found in the uninfected grass or the fungus alone. Five alkaloids were identified by capillary GC and GC-MS: N-formylloline as the major compound, followed by N-acetylloline, N-acetylnorloline and trace amounts of loline and N-methylloline. A routine procedure for the extraction and sensitive quantitative analysis of loline alkaloids by capillary GC is described. The loline alkaloid levels and concentrations were followed quantitatively over the growing season of the grass-endophyte association. A detailed analysis of the tissue distribution of the alkaloids is given. The total alkaloid level per plant increases from almost zero in early spring and reaches its highest level during seed maturation. It drops to almost zero with seed dispersal and stalk senescence but increases again during the subsequent period of vegetative growth in late summer. The highest alkaloid concentrations were found in young leaves in early spring, and in panicles (spikelets, seeds) and leaf pseudostems during the period of vegetative growth in late summer and autumn. During seed germination loline alkaloids are not degraded, however, a significant proportion (about 20%) are lost by leaching, mainly during seed imbibition. Within a seed the embryo was found to contain a two-fold higher alkaloid concentration than the remaining seed tissue.

Some Effects of Water Potential upon Endophytic Acremonium spp. in Culture

Some Effects of Water Potential upon Endophytic Acremonium spp. in Culture