Chemotypic diversity of bioprotective grass endophytes based on genome analyses, with new insights from a Mediterranean-climate region in Isfahan Province, Iran.

species are systemic, often seed-transmissible symbionts (endophytes) of cool-season grasses (Poaceae subfam. Poöideae) that produce up to four classes of bioprotective alkaloids. Whereas haploid species may reproduce sexually and transmit between host plants (horizontally), many species are polyploid hybrids that are exclusively transmitted via seeds (vertically).

Transcriptome analysis of strains in tall fescue in response to drought stress.

, a systemic fungal symbiont (endophyte) of tall fescue (), has been documented to confer to this grass better persistence than plants lacking the endophyte, especially under stress conditions such as drought. The response, if any, of the endophyte to imposition of stress on the host plant has not been characterized previously. Therefore, we investigated effects on gene expression by and a related endophyte when plant-endophyte symbiota were subjected to acute water-deficit stress.

Differential gene expression in tall fescue tissues in response to water deficit.

Tall fescue (Festuca arundinacea Schreb.) is a popular pasture and turf grass particularly known for drought resistance, allowing for its persistence in locations that are unfavorable for other cool-season grasses. Also, its seed-borne fungal symbiont (endophyte) Epichloë coenophiala, which resides in the crown and pseudostem, can be a contributing factor in its drought tolerance.

Cross-species transcriptomics identifies core regulatory changes differentiating the asymptomatic asexual and virulent sexual life cycles of grass-symbiotic Epichloë fungi.

Fungi from the genus Epichloë form systemic endobiotic infections of cool season grasses, producing a range of host-protective natural products in return for access to nutrients. These infections are asymptomatic during vegetative host growth, with associations between asexual Epichloë spp. and their hosts considered mutualistic.

Transcriptome Analysis and Differential Expression in Tall Fescue Harboring Different Endophyte Strains in Response to Water Deficit.

Two tall fescue [Lolium arundinaceum (Schreb.) Darbysh. = Schedonorus arundinaceus (Schreb.

Infection Rates and Alkaloid Patterns of Different Grass Species with Systemic Endophytes.

Symbiotic species are fungal endophytes of cool-season grasses that can produce alkaloids with toxicity to vertebrates and/or invertebrates. Monitoring infections and presence of alkaloids in grasses infected with species can provide an estimate of possible intoxication risks for livestock. We sampled 3,046 individuals of 13 different grass species in three regions on 150 study sites in Germany.

Transcriptomics of Epichloë-Grass Symbioses in Host Vegetative and Reproductive Stages.

Epichloë species are fungal symbionts (endophytes) of cool-season grasses that transmit vertically via inflorescence primordia (IP), ovaries (OV), and ultimately, embryos. Epichloë coenophiala, an endophyte of tall fescue (Schedonorus arundinaceus), provides multiple protective benefits to the grass. We conducted transcriptome analysis of the tall fescue-E.

Molecular identification and characterization of endophytes from uncultivated barley.

Epichloë species (Clavicipitaceae, Ascomycota) are endophytic symbionts of many cool-season grasses. Many interactions between Epichloë and their host grasses contribute to plant growth promotion, protection from many pathogens and insect pests, and tolerance to drought stress. Resistance to insect herbivores by endophytes associated with Hordeum species has been previously shown to vary depending on the endophyte-grass-insect combination.

Epichloë festucae endophytic growth in florets, seeds, and seedlings of perennial ryegrass (Lolium perenne).

Many symbiotic Epichloë species are seed-transmitted in their grass hosts. For a detailed investigation of Epichloë festucae colonization throughout the life cycle of its host, the authors transformed strain Fl1 with a fungal-active gene for enhanced cyan-fluorescent protein (eCFP), introduced it into perennial ryegrass (Lolium perenne), and used confocal microscopy to track its growth in the shoot apex, floral primordium, floral organs, seeds, and seedlings. Hyphae intercellularly colonized leaf sheaths, blades, true stems, and leaf primordia, and among floral primordia the endophyte exhibited different levels of colonization.

Transcriptome response of Lolium arundinaceum to its fungal endophyte Epichloë coenophiala.

Tall fescue (Lolium arundinaceum) is one of the primary forage and turf grasses in temperate regions of the world. A number of favourable characteristics of tall fescue are enhanced by its seed-transmissible fungal symbiont (endophyte) Epichloë coenophiala. Our approach was to assemble the tall fescue transcriptome, then identify differentially expressed genes (DEGs) for endophyte-symbiotic (E+) vs endophyte-free (E-) clones in leaf blades, pseudostems, crowns and roots.

Enzymes from fungal and plant origin required for chemical diversification of insecticidal loline alkaloids in grass-Epichloë symbiota.

The lolines are a class of bioprotective alkaloids that are produced by Epichloë species, fungal endophytes of grasses. These alkaloids are saturated 1-aminopyrrolizidines with a C2 to C7 ether bridge, and are structurally differentiated by the various modifications of the 1-amino group: -NH2 (norloline), -NHCH3 (loline), -N(CH3)2 (N-methylloline), -N(CH3)Ac (N-acetylloline), -NHAc (N-acetylnorloline), and -N(CH3)CHO (N-formylloline). Other than the LolP cytochrome P450, which is required for conversion of N-methylloline to N-formylloline, the enzymatic steps for loline diversification have not yet been established.

Ether bridge formation in loline alkaloid biosynthesis.

Lolines are potent insecticidal agents produced by endophytic fungi of cool-season grasses. These alkaloids are composed of a pyrrolizidine ring system and an uncommon ether bridge linking carbons 2 and 7. Previous results indicated that 1-aminopyrrolizidine was a pathway intermediate.

Sequence analysis of hepatitis C virus from patients with relapse after a sustained virological response: relapse or reinfection?

Background: A sustained virological response (SVR) is the major end point of therapy for chronic hepatitis C virus (HCV) infection. Late relapse of infection is rare and poorly characterized. Three of 103 patients with a SVR treated at the National Institutes of Health had late relapse.

Tall fescue endophyte effects on tolerance to water-deficit stress.

Background: The endophytic fungus, Neotyphodium coenophialum, can enhance drought tolerance of its host grass, tall fescue. To investigate endophyte effects on plant responses to acute water deficit stress, we did comprehensive profiling of plant metabolite levels in both shoot and root tissues of genetically identical clone pairs of tall fescue with endophyte (E+) and without endophyte (E-) in response to direct water deficit stress. The E- clones were generated by treating E+ plants with fungicide and selectively propagating single tillers.

The epichloae: alkaloid diversity and roles in symbiosis with grasses.

Epichloae (Epichloë and Neotyphodium species; Clavicipitaceae) are fungi that live in systemic symbioses with cool-season grasses, and many produce alkaloids that are deterrent or toxic to herbivores. The epichloae colonize much of the aerial plant tissues, and most benignly colonize host seeds to transmit vertically. Of their four chemical classes of alkaloids, the ergot alkaloids and indole-diterpenes are active against mammals and insects, whereas peramine and lolines specifically affect insects.

Currencies of mutualisms: sources of alkaloid genes in vertically transmitted epichloae.

The epichloae (Epichloë and Neotyphodium species), a monophyletic group of fungi in the family Clavicipitaceae, are systemic symbionts of cool-season grasses (Poaceae subfamily Poöideae). Most epichloae are vertically transmitted in seeds (endophytes), and most produce alkaloids that attack nervous systems of potential herbivores. These protective metabolites include ergot alkaloids and indole-diterpenes (tremorgens), which are active in vertebrate systems, and lolines and peramine, which are more specific against invertebrates.

Plant-symbiotic fungi as chemical engineers: multi-genome analysis of the clavicipitaceae reveals dynamics of alkaloid loci.

The fungal family Clavicipitaceae includes plant symbionts and parasites that produce several psychoactive and bioprotective alkaloids. The family includes grass symbionts in the epichloae clade (Epichloë and Neotyphodium species), which are extraordinarily diverse both in their host interactions and in their alkaloid profiles. Epichloae produce alkaloids of four distinct classes, all of which deter insects, and some-including the infamous ergot alkaloids-have potent effects on mammals.

Randomised clinical trial: the benefit of combination therapy with adefovir and lamivudine for chronic hepatitis B.

Background: Combination antiviral therapy holds the promise of increasing response rates while decreasing antiviral resistance, but has yet to be shown to be beneficial or necessary in chronic hepatitis B.

Aim: To evaluate the benefit of combination therapy with adefovir and lamivudine versus adefovir alone in maintaining virological, biochemical and histological responses.

Methods: Patients with chronic hepatitis B with and without previous lamivudine therapy were randomised to receive adefovir alone (10 mg/daily) or adefovir and lamivudine (100 mg/daily) for up to 192 weeks.

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

Many cool-season grasses (Poaceae, subfam. Pooideae) possess seedborne 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 Epichloë species give rise to horizontally transmissible spores (ascospores).

Toxicity of endophyte-infected tall fescue alkaloids and grass metabolites on Pratylenchus scribneri.

ABSTRACT Neotyphodium coenophialum, an endophytic fungus associated with tall fescue grass, enhances host fitness and imparts pest resistance. This symbiotum is implicated in the reduction of stresses, including plant-parasitic nematodes. To substantiate this implication, toxicological effects of root extracts, polyphenolic fraction, ergot, and loline alkaloids from endophyte-infected tall fescue were investigated using Pratylenchus scribneri, a nematode pest of tall fescue.

Chemotaxis disruption in Pratylenchus scribneri by tall fescue root extracts and alkaloids.

Tall fescue (Festuca arundinacea) forms a symbiotic relationship with the clavicipitalean fungal endophyte Neotyphodium coenophialum. Endophyte-infected grass is tolerant to nematode, but the factors responsible are unknown. One objective of this work was to determine if root extracts of tall fescue effected chemoreceptor activity of Pratylenchus scribneri by using an in vitro chemoreception bioassay.

Regulation of a chemical defense against herbivory produced by symbiotic fungi in grass plants.

Neotyphodium uncinatum and Neotyphodium siegelii are fungal symbionts (endophytes) of meadow fescue (MF; Lolium pratense), which they protect from insects by producing loline alkaloids. High levels of lolines are produced following insect damage or mock herbivory (clipping). Although loline alkaloid levels were greatly elevated in regrowth after clipping, loline-alkaloid biosynthesis (LOL) gene expression in regrowth and basal tissues was similar to unclipped controls.

Clinical trial: pilot study of metformin for the treatment of non-alcoholic steatohepatitis.

Background: Non-alcoholic steatohepatitis (NASH) is a form of progressive fatty liver disease that is strongly associated with insulin resistance, which suggests that insulin sensitizing agents such as metformin may be beneficial for NASH.

Aim: To assess the effects of metformin on insulin sensitivity, body composition, serum alanine aminotransferase (ALT) levels and liver histology in patients with NASH.

Methods: Patients underwent liver biopsy, metabolic profiling and imaging studies before and at the end 48 weeks of metformin (2000 mg/day) therapy.

Loline alkaloids: Currencies of mutualism.

Several species of Lolium and other cool-season grasses (Poaceae subfamily Pooideae) tend to harbor symbiotic, seed-transmitted, fungi that enhance their fitness by various means. These fungal endophytes--species of Neotyphodium or Epichloë (Clavicipitaceae)--are known for production of antiherbivore metabolites such as the bioprotective loline alkaloids. Lolines are saturated pyrrolizidines with an exo-1-amine and an ether bridge between C-2 and C-7.