Virus diseases of perennial pasture legumes in Australia: incidences, losses, epidemiology, and management

2013 ◽  
Vol 64 (3) ◽  
pp. 199 ◽  
Author(s):  
Roger A. C. Jones
Keyword(s):  
Mosaic Virus ◽  
White Clover ◽  
Large Scale ◽  
Current Knowledge ◽  
Alfalfa Mosaic Virus ◽  
South Australia ◽  
Control Measures ◽  
Virus Diseases ◽  
Virus Identification ◽  
Pasture Legumes

This article reviews current knowledge for Australia over the occurrence, losses caused, epidemiology, and management of virus diseases of perennial pasture legumes. Currently, 24 viruses have been found infecting perennial pasture legumes, and one or more viruses have been detected in 21 of these species. These viruses are transmitted by insect vectors, non-persistently or persistently, by contact or via seed. Their modes of transmission are critical factors determining their incidences within pastures in different climatic zones. Large-scale national or state surveys of lucerne (alfalfa) (Medicago sativa) and white clover (Trifolium repens) pastures revealed that some viruses reach high incidences. Infection with Alfalfa mosaic virus (AMV) was very widespread in lucerne stands, and with AMV and White clover mosaic virus (WClMV) in white clover pastures. Several other viruses are potentially important in pastures in these and other perennial temperate/Mediterranean pasture species. Data demonstrating herbage yield losses, diminished pasture persistence, and impaired nitrogen fixation/nodule function are available for AMV in lucerne, and AMV, WClMV, and Clover yellow vein virus in white clover. Integrated Disease Management approaches involving phytosanitary, cultural, chemical, and host resistance control measures are available to minimise virus infection in lucerne and white clover. Research on virus diseases of perennial tropical–subtropical pasture legumes has focussed almost entirely on virus identification, and information on their incidences in pastures, the losses they cause, and how to control them is lacking. Overall, viruses of perennial pasture legumes are least studied in South Australia and the Northern Territory. These and other critical research and development gaps that need addressing are identified.

Virus diseases of annual pasture legumes: incidences, losses, epidemiology, and management

2012 ◽  
Vol 63 (5) ◽  
pp. 399 ◽  
Author(s):  
Roger A. C. Jones
Keyword(s):  
Large Scale ◽  
Current Knowledge ◽  
Subterranean Clover ◽  
Summer Rainfall ◽  
Virus Diseases ◽  
Pasture Legumes ◽  
Improvement Programs ◽  
Annual Medics ◽  
Grazed Swards ◽  
Pasture Legume

This paper reviews current knowledge concerning the occurrence, losses caused, epidemiology, and management of virus diseases of annual pasture legumes. The viruses commonly present are spread by contact, or aphid vectors either non-persistently or persistently. Whether they are seed-borne and their means of transmission are critical factors determining their incidences within pastures in climatic zones with dry summers or substantial summer rainfall. Large-scale national or state surveys of subterranean clover pastures revealed that some viruses reach high infection incidences. Contamination with seed-borne viruses was widespread in plots belonging to annual pasture legume improvement programs and seed stocks of subterranean clover, annual medics, and alternative annual pasture legumes, and in commercial annual medic seed stocks. Yield loss studies with grazed swards were completed for three common viruses: two in subterranean clover and one in annual medics. These studies demonstrated considerable virus-induced losses in herbage and seed yields, and established that virus infection causes deteriorated pastures with high weed contents even when foliar symptoms are mild. Comprehensive integrated disease management tactics involving phytosanitary, cultural, chemical, or host resistance measures were devised for these three viruses in infected pastures, and for seed-borne viruses in annual pasture legume improvement programs. Several other viruses are potentially important, but, with these, quantification of losses caused in grazed swards is lacking and information on incidences in pastures is currently insufficient. Critical research and development gaps that need addressing are identified.

scholarly journals Viruses of White Clover in Pastures of Pennsylvania, New York, and Vermont

Plant Disease ◽  
1997 ◽  
Vol 81 (7) ◽  
pp. 817-820 ◽  
Author(s):  
Robert T. Sherwood
Keyword(s):  
New York ◽  
Mosaic Virus ◽  
White Clover ◽  
Significant Variation ◽  
Alfalfa Mosaic Virus ◽  
Red Clover ◽  
Yellow Mosaic Virus ◽  
Peanut Stunt Virus ◽  
Clover Yellow Mosaic Virus ◽  
White Clover Mosaic Virus

Incidence of six viruses was tested in white clover from 28 rotationally grazed pastures of Pennsylvania (PA), New York (NY), and Vermont (VT). Each of 17 PA pastures was sampled fall 1994, spring 1995, fall 1995, and spring 1996, and 10 pastures were sampled fall 1996. Each of five NY and six VT pastures was sampled spring and fall 1995 and 1996. Enzyme-linked immunosorbent assays (ELISA) were conducted for red clover vein mosaic virus (RCVMV), white clover mosaic virus (WCMV), alfalfa mosaic virus (AlMV), peanut stunt virus (PSV), clover yellow mosaic virus (CYMV), and the potyvirus group (POTY). RCVMV, WCMV, AlMV, and POTY were detected in 28, 28, 27, and 25 of the 28 pastures and in 67, 32, 30, and 7% of the 3,065 samples tested, respectively. PSV occurred at low to moderate levels in 11 PA pastures. PSV was rare in NY and was not detected in VT. CYMV was never found. Incidence of each virus varied significantly among pastures. For any given virus, there was not a significant variation in incidence among sampling dates within the NY-VT samples. RCVMV, WCMV, and POTY varied among dates within PA.

The sense and antisense coat protein gene of alfalfa mosaic virus strain N20 confers protection in transgenic tobacco plants

1997 ◽  
Vol 48 (4) ◽  
pp. 503 ◽  
Author(s):  
K. W. Jayasena ◽  
B. J. Ingham ◽  
M. R. Hajimorad ◽  
J. W. Randles
Keyword(s):  
Coat Protein ◽  
Mosaic Virus ◽  
Coat Protein Gene ◽  
Protein Gene ◽  
Alfalfa Mosaic Virus ◽  
35S Promoter ◽  
Pasture Legumes ◽  
Nicotiana Tabacum L ◽  
Sense Orientation ◽  
A Minor

The coat protein gene of a South Australian strain of alfalfa mosaic virus (AMV-N20 [NcS]) has been cloned, sequenced, and transferred into Nicotiana tabacum L. cv. Xanthi via Agrobacterium tumefaciens under the control of the CaMV 35S promoter. A number of lines (T0 generation) were selected with the coat protein gene either in sense orientation (CP+) or in antisense orientation (CP–). The T0 plants were tested for their gene expression and susceptibility to the homologous AMV strain. A significant delay in the onset of symptoms and a reduction in virus accumulation was observed in CP+ plants mechanically inoculated with AMV. CP– plants were also significantly protected but less so than the CP+ plants. Plants transformed with the expression vector only (CP0) showed a minor resistance to local infection on inoculated leaves compared with untransformed plants. The strategy of coat protein mediated protection (CPMP) using the CP gene in either messenger sense or antisense would therefore be appropriate for testing on economically important pasture legumes.

White clover (Trifolium repens) and associated viruses in the subalpine region of south-eastern Australia: implications for GMO risk assessment

2004 ◽  
Vol 52 (3) ◽  
pp. 321 ◽  
Author(s):  
R. C. Godfree ◽  
P. W. G. Chu ◽  
M. J. Woods
Keyword(s):  
Mosaic Virus ◽  
Plant Communities ◽  
White Clover ◽  
Alfalfa Mosaic Virus ◽  
Yellow Vein ◽  
Native Plant ◽  
Eastern Australia ◽  
Clover Yellow Vein Virus ◽  
Subalpine Region ◽  
White Clover Mosaic Virus

Over the past several years, increased emphasis has been placed on conducting comprehensive ecological-risk assessments of virus-resistant genetically modified organisms (GMOs) prior to their release into the environment. In this paper we report on the first stage in our assessment of the level of risk posed by virus-resistant transgenic Trifolium repens L. (white clover) to native plant communities in south-eastern Australia. We investigated the distribution, abundance and phytosociological characteristics of naturalised T. repens populations in two areas in the subalpine region of New South Wales (NSW) and the Australian Capital Territory (ACT), and determined the distribution and abundance of Alfalfa mosaic virus, Clover yellow vein virus and White clover mosaic virus in 31 populations of white clover in this region. We found that T. repens is a significant component of Poa grasslands and Eucalyptus–Poa woodlands in the subalpine region, but is absent or rare in Eucalyptus species forests and Carex–Poa species bogs. Clover yellow vein virus was by far the most common virus in the study area, being present in 18% of T. repens plants across a wide range of plant communities. Alfalfa mosaic virus and White clover mosaic virus were each recorded in only one white-clover population growing in a native plant community. We conclude that white clover is a significant constituent of subalpine grasslands and woodlands in the region studied, and that of the viruses investigated, Clover yellow vein virus is the most abundant and widespread.

Alfalfa mosaic virus. [Distribution map].

2002 ◽  
Author(s):  
Keyword(s):  
New York ◽  
South Carolina ◽  
Mosaic Virus ◽  
Prince Edward Island ◽  
Alfalfa Mosaic Virus ◽  
South Australia ◽  
Distribution Map ◽  
Central Russia ◽  
South Wales ◽  
Wide Range

Abstract A new distribution map is provided for Alfalfa mosaic virus Viruses: Bromoviridae: Alfamovirus Attacks a very wide range of hosts. Information is given on the geographical distribution in EUROPE, Austria, Belarus, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Lithuania, Netherlands, Poland, Portugal, Romania, Central Russia Russia, Southern Russia, Slovakia, Slovenia, Spain, Switzerland, UK, Ukraine, Yugoslavia (Fed. Rep.), ASIA, Bangladesh, China, Nei, Menggu, Shaanxi, Zhejiang, India, Maharashtra, Iran, Iraq, Israel, Japan, Hokkaido, Honshu, Jordan, Korea Republic, Kyrgyzstan, Lebanon, Myanmar, Nepal, Pakistan, Saudi Arabia, Syria, Taiwan, Tajikistan, Turkey, Uzbekistan, Yemen, AFRICA, Algeria, Egypt, Ethiopia, Kenya, Libya, Morocco, South Africa, Sudan, Tanzania, Tunisia, Zambia, NORTH AMERICA, Canada, Alberta, British Columbia, Manitoba, New Brunswick, Ontario, Prince Edward Island, Quebec, Mexico, USA, Alabama, Arkansas, California, Connecticut, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Vermont, Virginia, Washington, Wisconsin, Wyoming, SOUTH AMERICA, Argentina, Brazil, Parana, Chile, Colombia, Peru, Venezuela, OCEANIA, Australia, New South Wales, Queensland, South Australia, Tasmania, Victoria, Western Australia, New Zealand.

Bean leafroll virus is widespread in subterranean clover (Trifolium subterraneum L.) seed crops and can be persistently transmitted by bluegreen aphid (Acyrthosiphon kondoi Shinji)

2012 ◽  
Vol 63 (9) ◽  
pp. 902 ◽  
Author(s):  
D. M. Peck ◽  
N. Habili ◽  
R. M. Nair ◽  
J. W. Randles ◽  
C. T. de Koning ◽  
...  
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Seed Production ◽  
Alfalfa Mosaic Virus ◽  
South Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Bean Leafroll Virus ◽  
Leafroll Virus ◽  
Clover Seed

In the mid 2000s subterranean clover (Trifolium subterraneum) seed producers in South Australia reported symptoms of a red-leaf disease in fields with reduced seed yields. The red-leaf symptoms resembled those caused by several clover-infecting viruses. A set of molecular diagnostic tools were developed for the following viruses which are known to infect subterranean clover: Alfalfa mosaic virus; Bean leafroll virus (BLRV); Beet western yellows virus; Bean yellow mosaic virus; Cucumber mosaic virus; Pea seed-borne mosaic virus; Soybean dwarf virus and Subterranean clover stunt virus. Surveys of subterranean clover seed production fields in 2008 in the south-east of South Australia and western Victoria identified Bean leafroll virus, Alfalfa mosaic virus and Cucumber mosaic virus as present, with BLRV the most widespread. Surveys of pasture seed production fields and pasture evaluation trials in 2009 confirmed that BLRV was widespread. This result will allow seed producers to determine whether control measures directed against BLRV will overcome their seed losses. Bluegreen aphid (Acyrthosiphon kondoi) was implicated as a potential vector of BLRV because it was observed to be colonising lucerne plants adjacent to subterranean clover seed production paddocks with BLRV, and in a glasshouse trial it transmitted BLRV from an infected lucerne plant to subterranean clover in a persistent manner.

scholarly journals First Report of Alfalfa mosaic virus Associated with Severe Mosaic and Mottling of Pepper (Capsicum annuum) and White Clover (Trifolium repens) in Oklahoma

Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1705-1705 ◽  
Author(s):  
O. A. Abdalla ◽  
A. Ali
Keyword(s):  
United States ◽  
Mosaic Virus ◽  
Capsicum Annuum ◽  
White Clover ◽  
Trifolium Repens ◽  
Alfalfa Mosaic Virus ◽  
The United States ◽  
Morphological Data ◽  
Total Rna ◽  
First Report

Alfalfa mosaic virus (AMV), a member of the genus Alfamovirus, family Bromoviridae (1), has been reported in 44 states in the United States excluding Oklahoma. During a cucurbit survey in the summer of 2010, severe mosaic and mottling symptoms were observed on many peppers (Capsicum annuum) and white clover (Trifolium repens) plants in Tulsa, Oklahoma. Symptomatic leaf samples from 15 pepper and two white clover plants were collected in the Bixby area and analyzed serologically by dot-immunobinding assay (DIBA) using specific polyclonal antibodies against AMV (Agdia, Inc). Seven out of 15 pepper samples and both white clover samples were tested positive by DIBA to AMV. The remaining symptomatic samples were positive to Cucumber mosaic virus (CMV). Total RNA was extracted from DIBA positive AMV samples by Tri-reagent method. A small aliquot of total RNA was tested by reverse transcription (RT)-PCR using specific primers: AMV-F 5′ GTCCGCGATCTCTTAAAT 3′ and AMV-R 5′ GAAGTTTGGGTCGAGAGA 3′ that were designed to amplify 900 bp of the AMV-RNA 3. Analysis of the PCR products on agarose gel electrophoreses showed that all tested samples showed a band of the expected size while DIBA negative AMV samples did not produce any band. The amplified PCR product (900 bp) obtained from pepper and white clover were cleaned with PCR purification kit (Qiagen, Germantown, MD) and directly sequenced bi-directionally using the above primers. Sequence analysis confirmed that this virus shared 97% identity at nucleotide sequence with RNA 3 of AMV isolate from Madison-USA (GenBank Accession No. K02703). For biological and morphological characterization of the virus, eight pepper plants were mechanically inoculated using 0.1 M K2HPO4 buffer (pH 7.2) with total RNA extracted from AMV positive pepper or white clover plant samples. One to two weeks post-inoculation, all inoculated plants produced severe mosaic, mottling, and stunting. Virus-like particles preparations were obtained from these symptomatic plants according to our previously described method (2) and electron microcopy examination showed typical AMV particles. These biological and morphological data further confirmed the presence of AMV infecting pepper and clover in Oklahoma. AMV is a significant pathogen worldwide and infects more than 600 species in 70 families, especially alfalfa, pepper, soybean, and tobacco (3). AMV has a worldwide distribution, including the United States, and particularly the Midwestern U.S. where the incidence of the virus is on the rise recently because of the presence of its vector (Aphis glycines) (4). To our knowledge, this is the first report of AMV infecting crops in Oklahoma, which could pose a threat to other economic crops grown in Oklahoma, especially soybean. References: (1) E. E. Mueller et al. Plant Dis. 91:266, 2007. (2) A. Ali et al. Plant Dis. 96:243, 2012. (3) J. F. Bol. Mol. Plant Path.4:1, 2003. (4) M. Malapi-Nelson et al. Plant Dis.93:1259, 2009.

scholarly journals First Report of Alfalfa mosaic virus Infecting Tedera (Bituminaria bituminosa (L.) C.H. Stirton var. albomarginata and crassiuscula) in Australia

Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1384-1384 ◽  
Author(s):  
R. A. C. Jones ◽  
D. Real ◽  
S. J. Vincent ◽  
B. E. Gajda ◽  
B. A. Coutts
Keyword(s):  
Mosaic Virus ◽  
Alfalfa Mosaic Virus ◽  
Plant Viruses ◽  
Yellow Mosaic Virus ◽  
Rt Pcr ◽  
First Report ◽  
Pasture Legumes ◽  
Bituminaria Bituminosa ◽  
Pcr Products ◽  
Burr Medic

Tedera (Bituminaria bituminosa (L.) C.H. Stirton vars albomarginata and crassiuscula) is being established as a perennial pasture legume in southwest Australia because of its drought tolerance and ability to persist well during the dry summer and autumn period. Calico (bright yellow mosaic) leaf symptoms occurred on occasional tedera plants growing in genetic evaluation plots containing spaced plants at Newdegate in 2007 and Buntine in 2010. Alfalfa mosaic virus (AlMV) infection was suspected as it often causes calico in infected plants (1,2) and infects perennial pasture legumes in local pastures (1,3). Because AlMV frequently infects Medicago sativa (alfalfa) in Australia and its seed stocks are commonly infected (1,3), M. sativa buffer rows were likely sources for spread by aphids to healthy tedera plants. When leaf samples from plants with typical calico symptoms from Newdegate (2007) and Buntine (2010) were tested by ELISA using poyclonal antisera to AlMV, Bean yellow mosaic virus (BYMV) and Cucumber mosaic virus (CMV), only AlMV was detected. When leaf samples from 864 asymptomatic spaced plants belonging to 34 tedera accessions growing at Newdegate and Mount Barker in 2010 were tested by ELISA, no AlMV, BYMV, or CMV were detected, despite presence of M. sativa buffer rows. A culture of AlMV isolate EW was maintained by serial planting of infected seed of M. polymorpha L. (burr medic) and selecting seed-infected seedlings (1,3). Ten plants each of 61 accessions from the local tedera breeding program were grown at 20°C in an insect-proof air conditioned glasshouse. They were inoculated by rubbing leaves with infective sap containing AlMV-EW or healthy sap (five plants each) using Celite abrasive. Inoculations were always done two to three times to the same plants. When both inoculated and tip leaf samples from each plant were tested by ELISA, AlMV was detected in 52 of 305 AlMV-inoculated plants belonging to 36 of 61 accessions. Inoculated leaves developed local necrotic or chlorotic spots or blotches, or symptomless infection. Systemic invasion was detected in 20 plants from 12 accessions. Koch's postulates were fulfilled in 12 plants from nine accessions (1 to 2 of 5 plants each), obvious calico symptoms developing in uninoculated leaves, and AlMV being detected in symptomatic samples by ELISA, inoculation of sap to diagnostic indicator hosts (2) and RT-PCR with AlMV CP gene primers. Direct RT-PCR products were sequenced and lodged in GenBank. When complete nucleotide CP sequences (666 nt) of two isolates from symptomatic tedera samples and two from alfalfa (Aq-JX112758, Hu-JX112759) were compared with that of AlMV-EW, those from tedera and EW were identical (JX112757) but had 99.1 to 99.2% identities to the alfalfa isolates. JX112757 had 99.4% identity with Italian tomato isolate Y09110. Systemically infected tedera foliage sometimes also developed vein clearing, mosaic, necrotic spotting, leaf deformation, leaf downcurling, or chlorosis. Later-formed leaves sometimes recovered, but plant growth was often stunted. No infection was detected in the 305 plants inoculated with healthy sap. To our knowledge, this is the first report of AlMV infecting tedera in Australia or elsewhere. References: (1) B. A. Coutts and R. A. C. Jones. Ann. Appl. Biol. 140:37, 2002. (2) E. M. J. Jaspars and L. Bos. Association of Applied Biologists, Descriptions of Plant Viruses No. 229, 1980. (3) R. A. C. Jones. Aust. J. Agric. Res. 55:757, 2004.

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