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Journal ArticleDOI: 10.1071/CP20299

A root aphid Aploneura lentisci is affected by Epichloë endophyte strain and impacts perennial ryegrass growth in the field

02 Mar 2021-Crop & Pasture Science (CSIRO Publishing)-Vol. 72, Iss: 2, pp 155-164
Abstract: The aphid Aploneura lentisci is widespread in Australia and New Zealand, living all year round on roots of its secondary grass hosts. The fungal endophyte (Epichloe festucae var. lolii), strain AR37 in Lolium perenne is known to greatly reduce populations and was a likely reason for the superior growth and persistence of this association previously observed in the field. Aphid populations were quantified in a field trial near Ballarat, comparing yields of perennial ryegrass infected with eight different endophyte strains and an endophyte-free (Nil) control in a common ryegrass background (Grasslands Samson (G. Samson)). AR37 and another endophyte strain, AR5, had significantly fewer aphids than all other endophytes. These differences were significantly related to yield increases taken before and after sampling that persisted until the end of the trial. In a pot trial comparing commercially available ryegrass-endophyte combinations with equivalent Nil controls, aphid numbers were lower on G. Samson AR37 and Banquet II with AR5 (Endo®5) than on all other cultivar-endophyte combinations. Compared with Nil controls, the common toxic strain in G. Samson, and two strains in Trojan also reduced aphid numbers. The AR5 endophyte produces the alkaloid ergovaline but high concentrations of this in roots of potted plants could not account for differences in root aphid numbers. Root concentrations of epoxyjanthitrems, the only known alkaloids produced by AR37, were low and unlikely to be the cause of resistance to A. lentisci.

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Topics: Ergovaline (58%), Endophyte (56%), Aphid (53%) ... show more

5 results found

Open accessJournal ArticleDOI: 10.3390/JOF6040322
John R. Caradus, Linda J. Johnson1Institutions (1)
27 Nov 2020-Journal of Fungi
Abstract: The relationship between Epichloe endophytes found in a wide range of temperate grasses spans the continuum from antagonistic to mutualistic. The diversity of asexual mutualistic types can be characterised by the types of alkaloids they produce in planta. Some of these are responsible for detrimental health and welfare issues of ruminants when consumed, while others protect the host plant from insect pests and pathogens. In many temperate regions they are an essential component of high producing resilient tall fescue and ryegrass swards. This obligate mutualism between fungus and host is a seed-borne technology that has resulted in several commercial products being used with high uptake rates by end-user farmers, particularly in New Zealand and to a lesser extent Australia and USA. However, this has not happened by chance. It has been reliant on multi-disciplinary research teams undertaking excellent science to understand the taxonomic relationships of these endophytes, their life cycle, symbiosis regulation at both the cellular and molecular level, and the impact of secondary metabolites, including an understanding of their mammalian toxicity and bioactivity against insects and pathogens. Additionally, agronomic trials and seed biology studies of these microbes have all contributed to the delivery of robust and efficacious products. The supply chain from science, through seed companies and retailers to the end-user farmer needs to be well resourced providing convincing information on the efficacy and ensuring effective quality control to result in a strong uptake of these Epichloe endophyte technologies in pastoral agriculture.

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Topics: Endophyte (56%), Epichloë (53%)

10 Citations

Open accessJournal ArticleDOI: 10.48130/GR-2021-0007
01 Jan 2021-
Abstract: Fungal Epichloe endophytes form symbiotic associations with many temperate grasses, such as Lolium and Festuca, giving their host grasses an ecological advantage. The importance of specific Epichloe endophytes in providing varying levels of protection against invertebrate pests has been well documented. Similarly, but with fewer studies, the benefits of Epichloe to host grasses in drought events has been shown. Endophyte-infected grasses show an improved persistence against herbivore insect attack as well as resilience under drought. However, there are relatively few studies that investigate the interaction between drought and insect pressure, and yet it is these combined pressures that can prove detrimental for a ryegrass or fescue crop. This review examines the current state of knowledge on the effects of Epichloe on the interactions of insects and drought in temperate grasses.

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Topics: Festuca (53%), Epichloë (53%), Endophyte (52%) ... show more

3 Citations

Open accessJournal ArticleDOI: 10.48130/GR-2021-0008
Alison J. Popay, Neil R. Cox1Institutions (1)
01 Jan 2021-
Abstract: The symbiotic relationship between Lolium perenne and Epichloe festucae var. lolii, a fungal endophyte that lives asymptomatically in its above-ground parts, benefits both the host and fungus. In an outdoor container experiment, the effects of three distinct endophyte haplotypes (AR1, AR37 and CT) on natural infestations of a root aphid, Aploneura lentisci and a mealybug Phenococcus graminicola were compared with an endophyte-free (Nil) control. Populations of these insects were suppressed in a genetically identical set of plants treated with insecticide. Over 18 months, foliar and root growth, tiller numbers and plant mortality were compared between the different endophyte treatments and between insecticide-treated and untreated plants. Hyphal densities were recorded once during the trial. Untreated plants infected with AR37 had the lowest populations of A. lentisci and P. graminicola, and the highest root and foliar growth compared with other treatments. Growth parameters of untreated plants infected with CT often exceeded that of AR1 and Nil due to low infestations of P. graminicola and lower populations of A. lentisci. Growth of Nil, AR1 and CT plants were higher in insecticide-treated than in corresponding untreated plants but was unaffected in AR37. Untreated Nil and AR1 plants had a lower survival than AR37 and CT plants. Cumulative root outgrowth for treated AR37 plants was significantly lower than for treated AR1 on three sampling occasions. These Epichloe haplotypes are primarily mutualists, although there are circumstances when they may be disadvantageous to their host. Opposing outcomes likely originate in the ecosystems in which associations evolved.

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Topics: Endophyte (57%), Graminicola (55%)

Open accessJournal ArticleDOI: 10.3390/ENCYCLOPEDIA1040083
27 Oct 2021-
Abstract: Asexual Epichloe are obligate fungal mutualists that form symbiosis with many temperate grass species, providing several advantages to the host. These advantages include protection against vertebrate and invertebrate herbivores (i.e., grazing livestock and invertebrate pests, respectively), improved resistance to phytopathogens, increased adaptation to drought stress, nutrient deficiency, and heavy metal-containing soils. Selected Epichloe strains are utilised in agriculture mainly for their pest resistance traits, which are moderated via the production of Epichloe-derived secondary metabolites. For pastoral agriculture, the use of these endophyte infected grasses requires the balancing of protection against insect pests with reduced impacts on animal health and welfare.

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Topics: Obligate (55%), Epichloë (54%), Endophyte (51%)

Journal ArticleDOI: 10.1111/EEA.13115
Abstract: The wheat sheath miner, Cerodontha australis Malloch (Diptera: Agromyzidae), is a small leaf‐ and stem‐mining fly that is native to New Zealand and eastern Australia where it feeds on grasses and cereals. Although not considered to be a major insect pest of pastures in New Zealand, it can be abundant during spring and summer in Waikato, New Zealand, and infests tillers of the introduced pasture plant, perennial ryegrass, Lolium perenne L. (Poaceae). Cerodontha australis is not deterred from feeding on L. perenne infected with commercially available strains of the fungal endophyte Epichloë festucae var. lolii, which have been shown to provide protection from a range of other insect pests. In this study, three‐pot trials and periodic examination over 18 months of field‐collected L. perenne tillers showed that two Epichloë endophyte strains, AR47 and AR48, reduced the survival and feeding damage by C. australis larvae, but there was no evidence of an effect on adult female feeding or oviposition. Compared to other strains of E. festucae var. lolii endophytes tested, plants infected with AR47 and AR48 had fewer and smaller larvae and less larval mining. The number of tillers with mining was reduced in AR47 relative to endophyte‐free (Nil) by 57.1% (ranging from 25.0 to 92.5% across trials) and in AR48 by 67.1% (26.3–100%). Larvae in AR47 and AR48 were found further from the base of the tiller where they were less likely to damage the meristem and cause tiller death. The number of larvae and pupae in pseudostems was reduced in AR47 and AR48 compared with Nil by 78.4 and 82.0%, respectively, in the field trial. Very few larvae survived to pupation in AR47 and AR48 plants, with a reduction compared to Nil of over 81.5% in AR47 and over 97% in AR48 in each of the four trials presented here.

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Topics: Lolium perenne (54%)

30 results found

Journal ArticleDOI: 10.1890/03-0352
Andrea F. Huberty1, Robert F. Denno1Institutions (1)
01 May 2004-Ecology
Abstract: Traditionally, herbivorous insects are thought to exhibit enhanced performance and outbreak dynamics on water-stressed host plants due to induced changes in plant physiology. Recent experimental studies, however, provide mixed support for this historical view. To test the plant-stress hypothesis (PSH), we employed two methods (the traditional vote-counting approach and meta-analysis) to assess published studies that investigated insect responses to experimentally induced water-deficit in plants. For insects, we examined how water deficit affects survivorship, fecundity, density, relative growth rate, and oviposition preference. Responses were analyzed by major feeding guild (sap-feeding insects and chewing insects) and for the subguilds of sap-feeders (phloem, mesophyll, and xylem feeders) and chewing insects (free-living chewers, borers, leaf miners, and gall-formers). Both vote counting and meta-analysis found strong negative effects of water stress on the performance of sap-feeding insects at large and...

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600 Citations

Journal ArticleDOI: 10.1080/00480169.1981.34839
Abstract: Sir, — In recent years, much research effort has been directed towards identifying the cause of Ryegrass staggers (RGS). Many promising leads have been investigated, including studies of fungi in soil, ryegrass leaves, and dead leaf litter that could produce tremorgenic mycotoxins(3). Several groups of fungi produce tremorgens(4) which, when injected into sheep, produce symptoms similar to those in field outbreaks of RGS. However, under field conditions, populations of these fungi have not been shown to differ significantly between toxic and non-toxic pasture(7) (McKenzie & Byford, unpublished data).

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Topics: Lolium (53%)

297 Citations

Journal ArticleDOI: 10.1007/BF01012099
Abstract: Infection of ryegrass (Lolium perenne) by an endophytic fungus (Acremonium loliae) confers resistance against the Argentine stem weevil (Listronotus bonariensis). Extracts from ryegrass clones, infected and uninfected with A. loliae, were compared in a feeding choice bioassay, and several fractions were identified which affected stem weevil feeding behavior. One stem weevil feeding deterrent, peramine C12H17N5O, has been isolated from infected ryegrass and partially characterized as a basic indole derivative. Extracts from culturedA. loliae had no effect on stem weevil feeding behavior nor was peramine detected in the fungal cultures examined. Peramine and the other active substances are hydrophilic in contrast to the lipophilic properties reported for the neurotoxic lolitrems also isolated from ryegrass infected with A. loliae and associated with causing ryegrass staggers disorder in livestock. It is suggested that ryegrass staggers and stem weevil feeding deterrency may arise by different biochemical mechanisms.

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Topics: Weevil (57%), Listronotus bonariensis (54%), Lolium perenne (51%)

172 Citations

Journal ArticleDOI: 10.2135/CROPSCI2002.5100
01 Jan 2002-Crop Science
Abstract: Endophytic fungi in pasture grasses produce alkaloids which affect invertebrate and vertebrate herbivores. While the competence to produce an alkaloid is a property of the fungus, the host plant may moderate fungal activity. Host genetic influence on endophyte activity was studied in perennial ryegrass (Lolium perenne L.) infected with a common strain of Neotyphodium lolii (Latch, Christensen & Samuels) Glenn, Bacon & Hanlin. Progeny seedling families of a partial diallel cross and their 12 parent clones were compared in a glasshouse experiment. Peramine and ergovaline concentrations were determined by high pressure liquid chromatography (HPLC), and intensity of endophyte infection was determined by enzyme-linked immunosorbent assay (ELISA). Concentrations of peramine and ergovaline and the amount of endophyte mycelium in plants varied between families, consistently across two glasshouse cells and (for the HPLC data) two harvests. There was no indication of any maternal effects. Host genetic control was evident in significant general combining ability effects and smaller specific combining ability effects. Parent-progeny correlation coefficients were high, and narrow-sense heritability was estimated as 0.70, 0.72, and 0.58 respectively for ergovaline, peramine, and ELISA. Further analysis indicated little interaction between loci, and no directional dominance. The three traits were correlated, indicating that 41 and 65% of the genetically controlled variation in ergovaline and peramine concentrations, respectively, was a function of mycelial mass. However, there were departures from these relationships. Host plant selection may enable development of pastures with controlled low levels of toxic but ecologically beneficial endophyte metabolites.

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Topics: Ergovaline (65%), Endophyte (58%), Neotyphodium (52%) ... show more

92 Citations