scholarly journals Field performance of perennial ryegrass (Lolium oerenne) infected with toxin-free fungal endophytes (Neotyphodium spp.)

1999 ◽  
Vol 7 ◽  
pp. 113-122
Author(s):  
A.J. Popay ◽  
D.E. Hume ◽  
J.G. Baltus ◽  
G.C.M. Latch ◽  
B.A. Tapper ◽  
...  
Keyword(s):  
Insect Resistance ◽  
Perennial Ryegrass ◽  
Fungal Endophytes ◽  
Field Performance ◽  
Insect Damage ◽  
Wild Type ◽  
Pasture Production ◽  
Adult Feeding ◽  
Lolitrem B ◽  
Beetle Damage

A national series of six small plot trials were sown in 1996 and four in 1997 to evaluate the performance of six novel fungal endophytes in Grasslands Nui perennial ryegrass. These endophytes do not produce the mammalian toxins, ergovaline and lolitrem B, but produce peramine, a feeding deterrent to the major ryegrass pest, Argentine stem weevil (ASW). Trials included the naturally occurring endophyte (wild-type) which produces both toxins, and an endophyte-free (nil) treatment. Pasture production was measured regularly and samples were taken at least once each summer-autumn from all trials for assessment of ASW damage. Black beetle larval damage was recorded on three trials. The toxin-free endophytes, AR1, AR12, AR22 and the wild-type were equally effective at reducing ASW adult feeding and larval damage significantly below that which occurred in nil treatments. Ryegrass infected with AR1, AR12, AR22 and the wild-type endophyte was damaged less by black beetle larvae than ryegrass without endophyte. The effect of AR24 on insect damage was variable and two other toxin-free endophytes, AR17 and AR506, which had low infection rates, seldom reduced either ASW or black beetle damage. Yield differences between treatments were found on two of 21 sampling occasions between October and December and 12 of 30 sampling occasions between January and April. During summer-autumn, wild-type, AR1, AR12 and AR22 gave higher ryegrass yields than the nil, AR17 and AR506 treatments. In the second year of the 1996-sown trials, productivity of ryegrass with AR1 in the summer-autumn tended to be lower than that of the wild-type with significant differences occasionally occurring. Yield differences were correlated with either ASW or black beetle damage in North Island trials and with percent endophyte infection at all sites. Differences in yield at Lincoln, Canterbury, were attributed to pasture mealy bug. Three conclusions were drawn from these results: 1. Endophytes are very important for maximising ryegrass yield during summer and early autumn. 2. The effect of endophytes on yield is at least partly due to the insect resistance they impart. 3. The field performance of three toxin-free endophytes, AR1, AR12 and AR22, equalled that of the wild-type in terms of increased insect resistance but did not always match it in plant growth. Keywords: AR1, Argentine stem weevil, black beetle, endophyte strain, ergovaline, insect damage, lolitrem B, Neotyphodium lolii, ryegrass yield

scholarly journals Black beetle damage to perennial ryegrass infected with AR1 endophyte

2001 ◽  
pp. 267-271 ◽  
Author(s):  
A.J. Popay ◽  
J.G. Baltus
Keyword(s):  
New Zealand ◽  
Perennial Ryegrass ◽  
Field Trials ◽  
Fungal Endophyte ◽  
Reproductive Capacity ◽  
Wild Type ◽  
Adult Feeding ◽  
Important Pest ◽  
Pot Trial ◽  
Beetle Damage

AR1 is a new fungal endophyte that is being released in perennial ryegrass to New Zealand farmers. This endophyte lacks the mammalian toxins, ergovaline and lolitrem B, but produces peramine which provides resistance to a major ryegrass pest, Argentine stem weevil (Listronotus bonariensis). Black beetle (Heteronychus arator) is another important pest of ryegrass in northern areas of New Zealand. Adults are selective feeders, and avoid feeding on ryegrass infected with wildtype endophyte. A limited supply of suitable food greatly reduces their reproductive capacity. Laboratory and field investigations were therefore carried out to evaluate the degree of resistance to black beetle provided by AR1. Assessments of adult black beetle feeding were made on two field trials planted in autumn 1999. In both trials, adult feeding was significantly higher on ryegrass infected with AR1 than on ryegrass with wild-type but also significantly lower on AR1 than on endophyte-free ryegrass. In a pot trial conducted in summer, black beetle adult damage to 4-week-old AR1-infected ryegrass was no different from damage to endophyte-free plants. However in 6-month-old plants, damage to AR1 plants was significantly less than to endophyte-free plants and was similar to damage levels on wild-type plants. A further pot trial showed that beetles overwintering on AR1 ryegrass had a higher reproductive capacity than those overwintering on wild-type infected ryegrass. In February 2001, two field trials planted the previous June were sampled for black beetle larvae. Black beetle presence was significantly higher on endophyte-free plots than on wild-type plots, with presence on AR1 intermediate between these treatments. Ryegrass infected with AR1, although showing a degree of resistance to black beetle compared with endophyte-free ryegrass, is more susceptible to damage than wild-type, particularly in its first year of planting. Limited data indicate that older AR1 swards may have similar resistance to that of the wild-type but further research is needed to clarify the effect of stand maturity on black beetle damage to ryegrass infected with this new endophyte. Keywords: AR1, black beetle, endophyte, Heteronychus, Listronotus, Neotyphodium, ryegrass

scholarly journals Evaluation of several lolitrem-free endophyte/perennial ryegrass combinations

1991 ◽  
pp. 215-219 ◽  
Author(s):  
L.R. Fletcher ◽  
A.J. Popay ◽  
B.A. Tapper
Keyword(s):  
Weight Loss ◽  
Perennial Ryegrass ◽  
Fungal Endophyte ◽  
Feeding Deterrent ◽  
Animal Performance ◽  
Wild Type ◽  
Affected Animal ◽  
Lolitrem B

The fungal endophyte Acremonium lolii, in association with its ryegrass host, produces both peramine, a feeding deterrent to Argentine stem weevil,andlolitrem B,a neurotoxin causing ryegrass staggers. Endophyte strains vary in the ratio of production of these alkaloids in the ryegrass. In field evaluations of several endophyte/ryegrass - combinations, 'Endosafe', a zero lolitrem B, high peramine strain protected its host against Argentine stem weevil attack and did not cause ryegrass staggers in lambs grazing three of four ryegrass cultivars. Lambs on the endophyte-free and Endosafe combinations had the highest liveweight gains and while endophyte-free ryegrass did not cause ryegrass staggers it suffered significant stem weevil damage. Ryegrasses with their 'wild-type' endophyte and a high lolitrem B strain 'Waiau', had only minor stem weevil damage but caused severe ryegrass staggers and weight loss in lambs. Ryegrass with the no lolitrem B, low peramine strain, 'IOOA', suffered some stem weevil damage and although not causing ryegrass staggers, did cause weight loss in lambs. Ryegrass/endophyte metabolites in addition to lolitrem B may have affected animal performance on endophyte-infected ryegrass. Keywords endophytc, Endosafe, perennial ryegrass,ryegrass staggers, Argentine stem weevil, liveweight gains, peramine, lolitrem B

scholarly journals Olfactory responses of Argentine stem weevil to herbivory and endophyte-colonisation in perennial ryegrass

2021 ◽  
Author(s):  
Louise M. Hennessy ◽  
Alison J. Popay ◽  
Travis R. Glare ◽  
Sarah C. Finch ◽  
Vanessa M. Cave ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Perennial Ryegrass ◽  
Fungal Endophytes ◽  
Fungal Endophyte ◽  
Wild Type ◽  
Olfactory Responses ◽  
Plant Volatile ◽  
Endophyte Infection ◽  
Listronotus Bonariensis ◽  
Volatile Blend

AbstractArgentine stem weevil adults (ASW, Listronotus bonariensis) feed on the leaves of agricultural grasses and their larvae mine the pseudostem, causing extensive damage that can result in plant death. Plants emit volatiles that serve as signals to host-searching insects and these odours can be altered by both herbivory and fungal endophyte-infection. This study investigated whether ASW adults utilise olfaction to identify their host plants, perennial ryegrass (Lolium perenne), and if conspecific herbivory or the presence of Epichloë festucae var. lolii fungal endophytes (strain wild-type or AR1) influenced such responses. Results from olfactometer bioassays established that ASW adults were able to utilise their olfactory response to orient towards volatiles released by perennial ryegrass and further, the weevils displayed a preference for plants previously damaged by conspecific weevils. However, there was no evidence that weevils had the ability to distinguish between endophyte-infected and endophyte-free plants using olfaction alone. Using a push–pull extraction technique, thirteen volatile compounds were identified in the blend released by perennial ryegrass. Endophyte and herbivory were found to alter these volatile compounds and quantities emitted by this forage grass. This study suggests that despite observing differences in the plant volatile blend, ASW do not perceive endophyte (wild-type and AR1) using olfaction alone and must rely on other cues, e.g. contact chemoreception or post-ingestional malaise, to detect the presence of a bioactive endophyte in an otherwise acceptable host plant.

scholarly journals Establishing and maintaining a toxin-free pasture: a review

1999 ◽  
Vol 7 ◽  
pp. 123-132
Author(s):  
D.E. Hume
Keyword(s):  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Tall Fescue ◽  
Fungal Endophytes ◽  
Wild Type ◽  
Neotyphodium Lolii ◽  
Domestic Livestock ◽  
Buried Seed ◽  
On Farm ◽  
Sources Of Contamination

This paper reviews how new pastures may become contaminated with perennial ryegrass (Lolium perenne) infected with wild-type fungal endophytes (Neotyphodium lolii). These wild-type endophyte strains may be toxic to domestic livestock. Sources are from seed (natural reseeding, buried seed, sown seed, in dung, hay, carried on farm machinery) and survival of existing infected ryegrass plants. In particular, seed in soil and dung are reviewed. Contamination may occur both pre- and postestablishment. It is recommended that steps should be taken to minimise contamination from all sources when establishing new pastures. Although normal establishment practices for successful rapid establishment of weed-free pastures (e.g., cropping, fallow, herbicides) will minimise the risk of contamination, a number of cases highlight that extra time (e.g., 18-24 months planning rather 6- 12 months) and consideration of all sources of contamination is needed to minimise risk. Once established, further measures should be taken to prevent seed being transferred in dung or hay. This has implications when establishing pastures with endophyte-free ryegrasses, ryegrasses with selected non-toxic endophytes, a new ryegrass cultivar, or other grasses (e.g., tall fescue), whether for grazing by animals or for seed production. Keywords: endophyte, endophyte survival, faeces, Lolium perenne, natural reseeding, Neotyphodium lolii, pasture establishment, perennial ryegrass, seed burial, seed survival, tall fescue

Production and physiological effects of perennial ryegrass alkaloids under thermoneutral conditions in Merinos

2016 ◽  
Vol 56 (10) ◽  
pp. 1629 ◽  
Author(s):  
M. L. E. Henry ◽  
S. Kemp ◽  
I. J. Clarke ◽  
F. R. Dunshea ◽  
B. J. Leury
Keyword(s):  
Perennial Ryegrass ◽  
High Dose ◽  
Plasma Prolactin ◽  
Physiological Effects ◽  
Wild Type ◽  
Short Period ◽  
Lolitrem B ◽  
Whole Seed ◽  
C 50 ◽  
Linear Manner

A confined feeding study was conducted to compare the production and physiological effects of feeding three doses of wild-type perennial ryegrass alkaloids via whole seed to Merino sheep housed under thermoneutral conditions (21°C, 50% relative humidity). Eighteen Merino ewe weaners (16 months; initial bodyweight 47 ± 1.94 kg) were offered Nil, Low (50 µg/kg liveweight ergovaline, 22 µg/kg liveweight lolitrem B) or High (100 µg/kg liveweight ergovaline, 44 µg/kg liveweight lolitrem B) doses of alkaloids for 21 days. Dry matter intake tended (P = 0.072) to decrease in a linear manner with increasing dietary alkaloid concentration. Rectal temperature and respiration rate increased (P = 0.002 for both) in a linear manner with increasing dietary alkaloid concentration. Oxygen consumption increased linearly (P = 0.064) and quadratically (P = 0.015) with increasing alkaloid concentration, being highest in the Low dose and intermediate in the High dose group. Plasma prolactin decreased linearly (P = 0.002) with increasing dietary alkaloids. These data clearly show that animal production and efficiency are compromised when sheep consume perennial ryegrass alkaloids, even over a short period of time. This study indicates that a pyrogenic response can occur when alkaloids are consumed, even under thermoneutral conditions.

scholarly journals Cultivar and endophyte effects on a root aphid Aploneura lentisci in perennial ryegrass

2007 ◽  
Vol 60 ◽  
pp. 223-227 ◽  
Author(s):  
A.J. Popay ◽  
P.J. Gerard
Keyword(s):  
Growth Rate ◽  
Perennial Ryegrass ◽  
Significant Relationship ◽  
Fungal Endophytes ◽  
Dry Weight ◽  
Lolitrem B ◽  
Pot Trial ◽  
Alkaloid Profiles

In a pot trial fungal endophytes (Neotyphodium spp) with different alkaloid profiles were investigated for their effects on numbers of a root aphid (Aploneura lentisci) in perennial ryegrass Some endophytes were also tested in different cultivars (Nui Samson and Impact) Two endophytes AR37 and AR6 strongly suppressed root aphid numbers Wildtype had fewer aphids than endophytefree plants and AR1 Endophytes producing peramine only (AR1 AR12 AR22) and an endophyte producing peramine and lolitrem B (AR23) did not differ from endophytefree There were no cultivar by endophyte interactions but cultivar affected the strength of aphid response to Wildtype Comparisons of alkaloid profiles suggest that ergovaline (in Wildtype and AR6) and epoxyjanthitrems (in AR37) may affect root aphids whereas peramine and lolitrem B do not Differences in herbage dry weight of plants and a significant relationship between herbage dry weight and root aphid numbers indicated this aphid reduces the growth rate of plants

Fluctuations in the concentration of ergovaline and lolitrem B produced by the wild-type endophyte (Neotyphodium lolii) in perennial ryegrass (Lolium perenne) pasture

2011 ◽  
Vol 51 (12) ◽  
pp. 1098 ◽  
Author(s):  
K. F. M. Reed ◽  
Z. N. Nie ◽  
L. V. Walker ◽  
G. Kearney
Keyword(s):  
Seed Development ◽  
Perennial Ryegrass ◽  
Animal Health ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Wild Type ◽  
Neotyphodium Lolii ◽  
Eastern Australia ◽  
Lolitrem B

Mammalian toxins produced by the wild-type endophyte, Neotyphodium lolii, in perennial ryegrass (PRG) pasture cause production losses and animal health and welfare problems in livestock. Managing this risk is limited by the lack of information on fluctuations in the concentration of toxin in Australian pasture. We investigated how the toxin concentrations may be related to recent observations of weather. Swards sown from common seedlots of two cultivars of wild endophyte-infected PRG, grazed short by sheep, were sampled at 2–4 weekly intervals from spring to autumn at two sites in Victoria. The highest concentration of ergovaline and lolitrem B was observed at Hamilton, the site with the longer-growing season. The concentration of ergovaline peaked in early summer, coinciding with seed development, and declined through summer, before increasing with the commencement of autumn growth. The concentration of lolitrem B remained low in summer, then rose in autumn. Variation between the two cultivars in the concentration of toxins was small and rarely significant. The concentration of ergovaline declined as the mean daily maximum temperature over the preceding 1–5 days increased. Similarly, for lolitrem B, the concentration declined over the temperature range 12−20°C, from 1.3 to 0.3 mg/kg. At Hamilton, where solar radiation and soil temperature were recorded, both were superior to maximum temperature for predicting lolitrem B. Serial sampling of PRG from old naturalised pasture on seven farms across south-eastern Australia found two seasonal peaks for both alkaloids in most pastures. The concentration of ergovaline reached or exceeded tolerance levels for livestock in 23 of 43 samples, compared with 5 of 43 for lolitrem B. Ergovaline concentrations initially peaked (at 1.0–1.6 mg/kg) when mature reproductive material was present (coinciding with peduncle elongation and seed development). In pastures with low grazing pressure, i.e. where growth was allowed to continue through summer, ergovaline concentration was relatively low (<0.7 mg/kg) but in a hard-grazed pasture (sward height 3 cm), the ergovaline concentration was greater (up to 1.1 mg/kg). Concentration of lolitrem B also peaked in December, except on pasture where growth continued through summer. High concentrations of lolitrem B associated with neurotoxic signs in sheep (viz. 2.4–3.9 mg/kg) were observed only in mid-summer and autumn, and only if conditions favoured growth or where close grazing by sheep left the crown as the dominant source of herbage.

scholarly journals "Non-toxic" endophytes in ryegrass and their effect on livestock health and production

1999 ◽  
Vol 7 ◽  
pp. 133-139
Author(s):  
L.R. Fletcher
Keyword(s):  
Perennial Ryegrass ◽  
The Other ◽  
Serum Prolactin ◽  
Sheep Grazing ◽  
Wild Type ◽  
Respiration Rates ◽  
Neotyphodium Lolii ◽  
Lolitrem B ◽  
Livestock Health ◽  
Gross Margins

Ryegrass/endophyte associations have been developed which produce peramine, but not the endophyte toxins ergovaline or lolitrem B. Sheep grazing these ryegrasses in small paddocks and in a systems trial over three years gained weight as rapidly as those grazing endophyte-free ryegrass, and showed none of the adverse responses associated with grazing ryegrass naturally infected with wild-type endophyte (Neotyphodium lolii). Growth rates, rectal temperatures, respiration rates, serum prolactin concentrations, ryegrass staggers scores and scores for dag burdens were equivalent for the selected endophyte and nil endophyte treatments, whereas sheep grazing the wild-type endophyte treatment were adversely affected for all parameters. This was reflected in calculated gross margins for the systems trial of only $605 per hectare for the wild-type endophyte treatment compared with over $700 per hectare for each of the other treatments. To date there have been no conclusive studies of non-toxic endophyte with cattle. Keywords: AR1, dags, endophyte, ergovaline, liveweight gain, lolitrem B, Lolium perenne, Neotyphodium, peramine, perennial ryegrass, prolactin, sheep

scholarly journals Spontaneous in planta changes in fungal endophytes impact symbiosis

2007 ◽  
Vol 13 ◽  
pp. 191-193
Author(s):  
W.R. Simpson ◽  
M.J. Christensen ◽  
R.D. Johnson ◽  
J. Schmid
Keyword(s):  
Perennial Ryegrass ◽  
Cell Walls ◽  
Fungal Endophytes ◽  
Fungal Mycelium ◽  
Wild Type ◽  
In Planta ◽  
Neotyphodium Lolii ◽  
The Relationship ◽  
Host Tissues

The symbiosis between the asexual Ascomycetous fungi of the genus Neotyphodium and host grasses is considered to be symptomless. Symbioses involving Epichloë can show symptoms but this is restricted to the formation of stroma on floral structures. Fungal mycelium of both Epichloë and Neotyphodium endophytes occupy the intercellular space of plant tissues with no breach of host cell walls. Research involving these endophytes and their host grass symbioses relies on staining of host tissues and microscopic examination, immuno-detection or in-vitro isolation to determine infection status. This work reports on the observation of two independent instances of spontaneous change in the endophyte fungus that manifests as changes in the host grass vegetative morphology; one involving a genetically modified Epichloë festucae inoculated into a perennial ryegrass (Lolium perenne) population and the other a resident wild type Neotyphodium lolii. The relationship between wild type and variant fungus is confirmed as is the connection between variant fungus and host morphology. This work demonstrates that spontaneous in-planta changes in fungal endophytes occur and that these can impact on fungus/host grass symbioses. Keywords: Neotyphodium, Epichloë, symbiosis, endophyte, perennial ryegrass

Bt-Cry3Aa transgene expression reduces insect damage and improves growth in field-grown hybrid poplar

2014 ◽  
Vol 44 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Amy L. Klocko ◽  
Richard Meilan ◽  
Rosalind R. James ◽  
Venkatesh Viswanath ◽  
Cathleen Ma ◽  
...  
Keyword(s):  
Large Scale ◽  
Populus Deltoides ◽  
Integrated Management ◽  
Populus Trichocarpa ◽  
Hybrid Poplar ◽  
Volume Growth ◽  
Field Trials ◽  
Leaf Beetle ◽  
Insect Damage ◽  
Beetle Damage

The stability and value of transgenic pest resistance for promoting tree growth are poorly understood. These data are essential for determining if such trees could be beneficial to commercial growers in the face of substantial regulatory and marketing costs. We investigated growth and insect resistance in hybrid poplar expressing the cry3Aa transgene in two field trials. An initial screening of 502 trees comprising 51 transgenic gene insertion events in four clonal backgrounds (Populus trichocarpa × Populus deltoides, clones 24-305, 50-197, and 198-434; and P. deltoides × Populus nigra, clone OP-367) resulted in transgenic trees with greatly reduced insect damage. A large-scale study of 402 trees from nine insertion events in clone OP-367, conducted over two growing seasons, demonstrated reduced tree damage and significantly increased volume growth (mean 14%). Quantification of Cry3Aa protein indicated high levels of expression, which continued after 14 years of annual or biannual coppice in a clone bank. With integrated management, the cry3Aa gene appears to be a highly effective tool for protecting against leaf beetle damage and improving yields from poplar plantations.

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