Relationship between herbicide resistance in Lolium rigidum and populations of Anguina funesta, the nematode vector in annual ryegrass toxicity

1994 ◽  
Vol 34 (5) ◽  
pp. 633 ◽  
Author(s):  
IT Riley ◽  
GS Gill
Keyword(s):  
Herbicide Resistance ◽  
Rapid Development ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Annual Ryegrass Toxicity ◽  
Causal Bacterium

Samples of annual ryegrass (Lolium rigidum Gaudin) seed tested for herbicide resistance were examined for seed-galls of Anguina funesta, the nematode vector of Clavihacter toxicus the causal bacterium in annual ryegrass toxicity (ARGT). Of the 246 samples examined, 63% contained galls, with concentrations up to 1400 galls per 10 g of seed. Higher herbicide resistance was associated with increased concentrations of A. funesta. We conclude that use of selective herbicides for ARGT control may have contributed to the rapid development of herbicide resistance.

Development and application of polymerase chain reaction-based assays for Rathayibacter toxicus and a bacteriophage associated with annual ryegrass (Lolium rigidum) toxicity

2007 ◽  
Vol 47 (2) ◽  
pp. 177 ◽  
Author(s):  
M. C. Kowalski ◽  
D. Cahill ◽  
T. J. Doran ◽  
S. M. Colegate
Keyword(s):  
Polymerase Chain Reaction ◽  
Immunosorbent Assay ◽  
Potential Application ◽  
South Australia ◽  
Enzyme Linked Immunosorbent Assay ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Chain Reaction ◽  
Polymerase Chain ◽  
Annual Ryegrass Toxicity

Annual ryegrass toxicity (ARGT) is responsible for significant stock losses in South Australia and Western Australia. The toxicity is caused by corynetoxins produced by the bacterium Rathayibacter toxicus (with the possible involvement of a bacteriophage), which infects annual ryegrass (Lolium rigidum). Polymerase chain reaction (PCR)-based assays, compatible with an existing enzyme-linked immunosorbent assay for the corynetoxins, have been developed and used to screen L. rigidum for both the presence of R. toxicus and for the bacteriophage isolate NCPPB 3778. The results from analysing bacterially infected galls from toxic grain screenings showed a positive correlation between the presence of the bacterium and corynetoxins but not with the bacteriophage. Analysis of pasture-derived samples of annual ryegrass showed about a 50% correlation of corynetoxins with bacterial presence and about a 5% correlation of phage with the presence of the bacterium. These observations support the potential application of the PCR-based assays in providing a useful, complementary tool in the assessment of the likelihood of pasture and feed to cause ARGT and to enable a better understanding of the complex aetiology of ARGT.

Rapid estimation of corynetoxins in bacterial galls from annual ryegrass (Lolium rigidum Gaudin) by high-performance liquid chromatography

1985 ◽  
Vol 36 (1) ◽  
pp. 35 ◽  
Author(s):  
PA Cockrum ◽  
JA Edgar
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
South Australia ◽  
Reversed Phase ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Aqueous Methanol ◽  
The Individual ◽  
Annual Ryegrass Toxicity

A rapid and sensitive method is described for the extraction, detection and measurement of corynetoxins in ryegrass seed galls colonized by Corynebucterium rathayi. Excised galls are extracted with aqueous methanol and the extract analysed, without further purification, by reversed-phase high-performance liquid chromatography with detection by uItraviolet absorption. The method is applicable down to the level of a single gall or part of a gall with a minimum level of detection of about 0.25 �g using the equipment described. The corynetoxin content of the individual galls examined varied from below the detection limit to 10.6 �g. The highest level of corynetoxin in a single gall was 1.15% of gall weight. The corynetoxin composition of galls collected during outbreaks of annual ryegrass toxicity in South Australia, Western Australia and South Africa during a 19-year period were found to be similar.

scholarly journals Rapid On-Farm Testing of Resistance in Lolium rigidum to Key Pre- and Post-Emergence Herbicides

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1879
Author(s):  
Martina Badano Perez ◽  
Hugh J. Beckie ◽  
Gregory R. Cawthray ◽  
Danica E. Goggin ◽  
Roberto Busi
Keyword(s):  
Weed Control ◽  
Herbicide Resistance ◽  
Rapid Detection ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Herbicide Resistant ◽  
Primary Dormancy ◽  
Wide Range ◽  
Control Options ◽  
On Farm

Overreliance on herbicides for weed control is conducive to the evolution of herbicide resistance. Lolium rigidum (annual ryegrass) is a species that is prone to evolve resistance to a wide range of herbicide modes of action. Rapid detection of herbicide-resistant weed populations in the field can aid farmers to optimize the use of effective herbicides for their control. The feasibility and utility of a rapid 7-d agar-based assay to reliably detect L. rigidum resistant to key pre- and post-emergence herbicides including clethodim, glyphosate, pyroxasulfone and trifluralin were investigated in three phases: correlation with traditional pot-based dose-response assays, effect of seed dormancy, and stability of herbicides in agar. Easy-to-interpret results were obtained using non-dormant seeds from susceptible and resistant populations, and resistance was detected similarly as pot-based assays. However, the test is not suitable for trifluralin because of instability in agar as measured over a 10-d period, as well as freshly-harvested seeds due to primary dormancy. This study demonstrates the utility of a portable and rapid assay that allows for on-farm testing of clethodim, glyphosate, and pyroxasulfone resistance in L. rigidum, thereby aiding the identification and implementation of effective herbicide control options.

Production of corynetoxins in vitro by Corynebacterium sp. isolated from annual ryegrass seedheads

1988 ◽  
Vol 39 (1) ◽  
pp. 63 ◽  
Author(s):  
AL Payne ◽  
PA Cockrum
Keyword(s):  
Incubation Temperature ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
In Vitro Production ◽  
The Family ◽  
Agar Surface ◽  
Vitro Production ◽  
Corynebacterium Sp ◽  
Annual Ryegrass Toxicity

Corynetoxin complex is the family of tunicamycin-like antibiotics isolated from annual ryegrass (Lolium rigidum) seedheads infected with a plant pathogenic Corynebacterium and identified as the causative toxins for annual ryegrass toxicity (ARGT) in Australia. Only trace amounts of corynetoxins have been reported to be produced in vitro. Enhanced in vitro production of corynetoxins by Corynebacterium sp. has now been demonstrated. The important conditions required were growth on an agar surface, absence of light, low incubation temperature and strain of the organism. Strains of the Corynebaterium sp. grown under conditions not supporting corynetoxin production failed to produce corynetoxins when subsequently grown under more favourable conditions. Even when maintained under the most favourable conditions, toxigenicity of strains declined on repeated subculturing. While levels of toxin typically produced in vitro were only about 5% of those found in infected ryegrass seedheads, they were high enough to be a useful source of corynetoxins for experimental purposes.

A decade of monitoring herbicide resistance in Lolium rigidum in Australia

2006 ◽  
Vol 46 (9) ◽  
pp. 1151 ◽  
Author(s):  
J. C. Broster ◽  
J. E. Pratley
Keyword(s):  
Herbicide Resistance ◽  
Cultural Practices ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Herbicide Resistant ◽  
South Wales ◽  
Australian State ◽  
Group B ◽  
Random Survey ◽  
Group D

Charles Sturt University commenced herbicide resistance monitoring in 1991. A random survey in 1991 to determine the level of resistance in annual ryegrass (Lolium rigidum) to selective herbicides across the south-west slopes region of New South Wales found that 30% of samples were resistant to at least 1 herbicide. A subsequent survey of commercially available ryegrass seed found that 58% of these samples were resistant to at least 1 herbicide. As a result of these findings, a commercial testing service was established and has since received samples from a large proportion of the southern Australian cropping belt. Seventy-seven percent of samples tested were resistant to Group AI, 40% to Group B and 22% to Group AII herbicides. Lower levels of resistance were found to Group D (8%), Group C (1%) and Group M (0.4%) herbicides. The correlation between resistance in Group AI and AII herbicides was lower than expected given that these herbicides are considered to have the same mode of action. Within the Group AI herbicides the observed response of the samples was consistent across herbicide formulations. Resistance to clethodim varied from observed responses to other Group AII herbicides. The variation in resistance levels (and degree of multiple resistance) in each Australian state is discussed in relation to environmental conditions and cultural practices. The size of this dataset allows for the analysis of the relationships present among herbicide resistant annual ryegrass.

Epichloë occultans infection in Australian Lolium rigidum is associated with cropping history and environment but not with herbicide resistance status of host plant

2018 ◽  
Vol 69 (6) ◽  
pp. 642
Author(s):  
Joseph R. Moore ◽  
James E. Pratley ◽  
Leslie A. Weston ◽  
Wade J. Mace ◽  
John C. Broster ◽  
...  
Keyword(s):  
Herbicide Resistance ◽  
Invasive Plant ◽  
Fungal Endophyte ◽  
Infection Frequency ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Selection Pressures ◽  
Environmental Selection ◽  
Millennium Drought ◽  
Endophyte Infection

Annual ryegrass (Lolium rigidum Gaud.) is a troublesome invasive plant in southern Australian cropping systems and is typically infected with a fungal endophyte, Epichloë occultans. Potential links between herbicide resistance and endophyte infection were investigated in this study. We surveyed 391 ryegrass populations from geographically distinct, naturalised pasture and cropping areas across southern Australia and compared frequencies of seed-borne endophyte infection in the collected seed samples from mature annual ryegrass. Data on herbicide resistance from similar seedlots were cross-referenced with endophyte infection frequency to examine the potential relationship between herbicide resistance and endophyte infection. Seeds from cropping paddocks exhibited a significantly higher frequency of endophyte infection than pasture paddocks sampled from the same region. Frequencies of endophyte infection in annual ryegrass declined across Australia during 2001–09, whereas the opposite trend was observed during 2009–12. Impacts of the Australian Millennium Drought, the correspondingly altered rainfall patterns and environmental selection pressures have a role in determining observed endophyte infection frequencies. However, there was no significant correlation between endophyte frequency and herbicide resistance in the populations evaluated. Differences in endophyte infection frequencies were associated with farming practices, and require further examination to determine causative selection pressures encountered in Australian field settings.

Corynetoxins are not detoxicated by in vitro fermentation in ovine rumen fluid

1986 ◽  
Vol 37 (5) ◽  
pp. 523 ◽  
Author(s):  
P Vogel ◽  
MG McGrath
Keyword(s):  
Rumen Fluid ◽  
Annual Ryegrass ◽  
Inhibition Assay ◽  
Lolium Rigidum ◽  
In Vitro Fermentation ◽  
Bacterial Inhibition ◽  
Annual Ryegrass Toxicity

Tunicamycin and seed galls of annual ryegrass (Lolium rigidum) containing corynetoxins, the causal agents of annual ryegrass toxicity, were incubated in ovine rumen fluid-buffer mixtures. A bacterial inhibition assay of extracted incubation mixtures revealed that no detoxication occurred under these in vitro conditions.

scholarly journals Annual ryegrass toxicity – an animal disease caused by toxins produced by a bacterial plant pathogen

2012 ◽  
Vol 33 (1) ◽  
pp. 18 ◽  
Author(s):  
Jeremy Allen
Keyword(s):  
Plant Pathogen ◽  
Neurological Disease ◽  
Animal Disease ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Grain Crop ◽  
Bacterial Plant Pathogen ◽  
Annual Ryegrass Toxicity

Annual ryegrass toxicity (ARGT) is an acute and often fatal neurological disease of livestock caused by consumption of annual ryegrass (Lolium rigidum) seed heads infected with the bacterium Rathayibacter toxicus (formerly Clavibacter toxicus and Corynebacterium rathayi). These toxic seed heads may be present in pasture, crop stubbles or provided feed (hay, grain, crop fines or pellets).

Ecological field studies on Anguina funesta, the vector in annual ryegrass toxicity

1981 ◽  
Vol 32 (6) ◽  
pp. 917 ◽  
Author(s):  
AC McKay ◽  
JM Fisher ◽  
AJ Dube
Keyword(s):  
Environmental Conditions ◽  
Field Studies ◽  
Annual Ryegrass ◽  
Lolium Rigidum ◽  
Second Stage ◽  
Stage Of Development ◽  
Annual Ryegrass Toxicity

Entry of second-stage juveniles (J2) of Anguina funesta into the apex of Lolium rigidum was dependent on environmental conditions and so varied in 1978 and 1979. Penetration and initiation of galls dependent on stage of development of the plant, was more consistent and occurred in late August-early September. Two to three nematodes initiated each gall. The first egg was deposited at the end of September and the first J2 hatched in mid-October. The implications of these observations for control are discussed. Mowing and grazing, the fungus Dilophospora alopecuri, and good clover growth all showed promise in reducing numbers of the nematode.

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