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In field pea (Pisum sativum) crops worldwide, sowing seed with minimal Pea seed-borne mosaic virus (PSbMV) infection is crucial to manage its spread and the seed yield and quality losses it causes. The possibility of using seed fractionation to help decrease PSbMV infection in infected seed-stocks used for sowing crops was investigated. When six PSbMV-infected seed-lots of Australian field pea cvs Kaspa or PBA Twilight were passed through sieves of different mesh sizes to obtain different size fractions, PSbMV seed transmission rates to seedlings were significantly higher in the 6.5 mm fractions. Passing pea seed-lots through a 6.5 mm sieve can be used to: (i) provide a useful indicator warning of likely high seed infection levels, and (ii) contribute towards decreasing PSbMV infection levels below the % seed transmission risk threshold for sowing.

Legume crop cultivation is widespread in Greece and contributes significantly to the agricultural economy of the country. In contrast to pea, Pea seed-borne mosaic virus (PSbMV) detection and pathotype characterization in lentil is limited. The aim of this study was the molecular characterization of the first reported lentil isolate of PSbMV in Greece. Specific primers against three genes of PSbMV, namely the coat protein (CP) and the P1 and HC-Pro proteases have been designed and tested in RT-PCR detection and quantitation of the virus in lentil. Phylogenetic and recombination analysis of the Greek CP and HC-Pro amplicons was performed with the aim of detecting sequence variability indicative of pathotype classification. Moreover, the identified point mutations of the Greek HC-Pro sequence were further exploited in RT-RFLP protocols that together with the phylogenetic analysis lead to the classification of the Greek PSbMV isolate into pathogroup 1.

For the first time, Cucumber mosaic virus (CMV), Pea seed-borne mosaic virus (PSbMV) and Turnip yellows virus (TuYV) were detected in a naturally infected fenugreek (Trigonella foenum-graecum) crop in Australia. The level of infection reached an alarming 90%, 75% and 20% respectively for CMV, TuYV and PSbMV, resulting in total crop loss. Both CMV and TuYV were detected in non-symptomatic fenugreek plants while PSbMV was not. Seed lots from the crop in question were established, planted in the glasshouse and tested for a range of seed-borne viruses, none of which were detected. Additionally, fenugreek seedlings grown from the seeds in the glasshouse were found to be readily infected with a TuYV isolate from canola when inoculated using viruliferous Myzus persicae.

Tasmanian vegetable crops (broccoli, carrots, cauliflower, common bean, and pea) were tested for virus infection with Potyviruses (all crops), members of the Luteoviridae (all except carrot), Alfalfa mosaic virus (all except brassicas), Cucumber mosaic virus (all except carrot and cauliflower), Subterranean clover stunt virus (legumes only), Tomato spotted wilt virus (legumes only) and Cauliflower mosaic virus (brassicas only) over three seasons (2007–2010). Low (and sporadic) incidence of each virus (or virus group) was found in pea crops. Only Luteovirid and SCSV infections were found in bean crops at low frequency and incidence. Virus infection was not detected in carrot crops. Broccoli crops recorded generally low incidence of all four viruses or groups tested for, whilst cabbage crops recorded very low incidence of CaMV only. In the pea and broccoli crops members of the Luteoviridae were the most prevalent viruses detected. Samples that tested positive for generic Potyvirus and Luteoviridae tests were retested using virus specific antiserum and/or RT-PCR. Potyvirus detections (from pea crops in the first year of testing) were due to infection with Pea seed-borne mosaic virus (PSbMV). These samples were all sourced from a single imported seed line. Subsequent testing over the next two seasons failed to show evidence of PSbMV which may have been eliminated with destruction of the seed source. Molecular analyses of a selection of Luteovirid isolates revealed most infections were due to Turnip yellows virus with five isolates from pea belonging to a putative novel Polerovirus species with closest homology to Cucurbit aphid-borne yellows virus.

A survey was conducted to identify viruses affecting chickpea and lentil crops in the major production areas of Azerbaijan during June 2007 and May 2008. The survey covered randomly selected 16 farmers’ fields (13 chickpea and three lentil) and one lentil field in research station during 2007, and 14 fields (nine chickpea and five lentil fields) during 2008. Infection incidences were determined for 11 legume viruses by tissue blot immunoassays (TBIA) on 50–200 randomly samples collected from each field. The TBIA and confirmatory nucleic acid analyses indicated that Luteoviridae species [Beet western yellows virus (BWYV), Bean leafroll virus (BLRV) and Chickpea chlorotic stunt virus (CpCSV)] were collectively the most common viruses in chickpea and lentil fields followed by Faba bean necrotic yellows virus (FBNYV). Pea seed-borne mosaic virus (PSbMV) was not detected in chickpea but reached high incidences in lentil fields. This is the first survey of legume viruses in Azerbaijan and first record of FBNYV, BWYV, BLRV and CpCSV naturally infecting chickpea and lentil crops, and PSbMV infecting lentil crop in Azerbaijan.

Traditional plant breeding relies upon crosses and subsequent selection of genotypes to meet desirable traits. The incorporation of marker-assisted selection into breeding strategies would result in a reduction in the number of offspring to be propagated, selected and tested. In the case of pea (Pisum sativum L.), the testing of resistance to viral pathogens such as pea seed-borne mosaic virus (PSbMV) is included in the breeding process. Resistance to the common strains of PSbMV is conferred by a single recessive gene (eIF4E), localized on LG VI (sbm-1 locus). We have analyzed for variation in the eIF4E genomic sequences from 43 pea varieties and breeding lines, reported as donors of resistance. This enabled a comprehensive investigation of the eIF4E gene structure and mutations responsible for PSbMV resistance were identified. Subsequently, PCR-based and gene-specific single nucleotide polymorphism and co-dominant amplicon length polymorphism markers were developed. All together 60 accessions were analyzed using sequence data and/or allele specific DNA markers. Developed allele specific markers were reproducibly amplified across a broad spectra of pea varieties and breeding lines. These were found to be 100% accurate in detecting the presence of the respective alleles when compared to symptomology and ELISA, testing (74% reliable). Hence, these molecular markers will substantially speed-up PSbMV diagnosis and resistance breeding processes in pea.

Pea seed-borne mosaic virus (PSbMV) is not considered a problem in Australian lentils as no seed transmission in commercial lentil seed lots has so far been reported. PSbMV lentil-seed transmissible strains were found in accessions from the Australian germplasm collection that were imported from the USDA germplasm collection and were previously reported to contain PSbMV. Strategies to clean up infected entries and to avoid the spread of these strains to commercial fields are discussed.

Two virus resistance loci on linkage groups II and VI have provided the only sources of natural resistance against Pea seed-borne mosaic virus (PSbMV, Potyviridae) in the important crop plant Pisum sativum L. A combination of parallel approaches was used to collate linked markers, particularly for sbm-1 resistance on linkage group VI. We have identified sequences derived from the genes for the eukaryotic translation initiation factors eIF4E and eIF(iso)4E as being very tightly linked to the resistance gene clusters on linkage groups VI and II, respectively. In particular, no recombinants between sbm-1 and eIF4E were found amongst 500 individuals of an F2 cross between the BC4 resistant line (JI1405) and its recurrent susceptible parent 'Scout'. In a different mapping population, the gene eIF(iso)4E was also shown to be linked to sbm-2 on linkage group II. A parallel cDNA-AFLP comparison of pairs of resistant and susceptible lines also identified an expressed tag marker just 0.7 cM from sbm-1. eIF4E and eIF(iso)4E have been associated with resistance to related viruses in other hosts. This correlation strengthens the use of our markers as valuable tools to assist in breeding multiple virus resistances into peas, and identifies potential targets for resistance gene identification in pea.

In a survey for viruses of cultivated legumes in West Asia and North Africa, pea seed-borne mosaic virus (PSbMV) was found in faba bean, lentil and pea. Using ELISA, it was detected in 107 out of 1554 faba bean samples and 40 out of 496 lentil samples with virus-like symptoms collected in Algeria, Egypt, Ethiopia, Jordan, Lebanon., Libya, Morocco, Sudan, Tunisia and Turkey.

The location of sbm-1 on the Pisum sativum genetic map was determined by linkage analysis with eight syntenic molecular markers. Analysis of the progeny of two crosses confirmed that sbm-1 is on chromosome 6 and permitted a more detailed map of this chromosome to be constructed. The inclusion of Fed-1 and Prx-3 among the markers facilitated the comparison of our map with the classical genetic map of pea. The sbm-1 gene is most closely linked to RFLP marker GS185, being separated by a distance of about 8 cM. To determine the practical value of GS185 as a marker for sbm-1 in plant breeding programs, the GS185 hybridization pattern and virus-resistance phenotype were compared in of a collection of breeding lines and cultivars. Three GS185 hybridization patterns were discerned among the lines. A strong association was found between one of these patterns and resistance to PSbMV.

A total of 52 faba-bean (Vicia faba L.) fields, located in the main growing areas in Morocco were surveyed for viruses. From 240 samples with symptoms suggestive of virus infection, the following viruses were detected using electron microscopy, serology, and biological indexing: Alfalfa mosaic virus (AMV), bean yellow mosaic virus (BYMV), broad bean mottle virus (BBMV), broad bean stain virus (BBSV), broad bean true mosaic virus (BBTMV), pea earlybrowning virus (PEBV), pea enation mosaic virus (PEMV), pea seed-borne mosaic virus (PSbMV), and a complex of luteoviruses including bean leafroll virus (BLRV). This is the first report of the occurrence of BBTMV, PEMV, PSbMV, and the luteoviruses (including BLRV) of faba bean in Morcco.

The effect of the South Australian pathotype 4 isolate (S6) of pea seed-borne mosaic virus (PSbMV-S6) on the yield components of pea (cv. Dundale) was compared in a glasshouse trial with that of a North American pathotype 1 isolate (PSbMV-US). Plants inoculated mechanically with PSbMV-S6 showed systemic vein clearing, vein banding, severe mosaic, leaf distortion, abnormal tendril curling, stunting and colour break of petals, premature axillary shoot formation, delayed flowering and pod formation, and plants matured 14 days late. Seed yield was reduced by 82% and the virus was transmitted to 31% of seedlings. In comparison, PSbMV-US induced a transient, mild leaf rolling, stunting and colour break in petals with a less noticeable effect on axillary shoot production, and plants matured 7 days late. Seed yield was reduced by 35% and the virus was transmitted to 8% of seedlings. Infected plants raised from seed of plants infected with S6 were symptomless and matured 7 days late; seed yield was reduced by 52% and 12% of their seed contained virus. In contrast, some infected plants raised from seed of plants infected with PSbMV-US showed mild leaf rolling, but there was no significant effect on yield and 7% of seed contained virus. Thus, PSbMV-S6 not only severely affects seed yield, but changes in plant habit and time of maturation may have additional deleterious effects on plant performance in field crops.

Seven isolates of pea seed-borne mosaic virus (PSbMV) were compared on selectedPisum sativum L. differentials and by microprecipitin and SDS-gel serology and particle length. All isolates were characterized by 750 nm particle-length modes and were closely related serologically, but some were readily distinguished onP. sativum differentials. Isolate distinctions were of the magnitude typical for virus strains. Differentials, diversePisum germplasm from U.S. Plant Introduction accessions, provided a practical means of PSbMV strain differentiation. Tussen 1966 en 1970 zijn in verschillende landen virussen gerapporteerd, die bij erwt met zaad overgaan, maar in verschillende opzichten leken te verschillen. Isolaten uit Japan en de USA bleken serologisch nauw aan elkaar verwant, zo niet identiek te zijn. Daarom werd de internationale naam ‘pea seed-borne mosaic virus’ voorgesteld. In Nederland was het virus beschreven onder de naam erwterolmozaiekvirus. Zeven isolaten van het virus uit de USA, Japan, Tsjechoslowakije en Nederland zijn nader met elkaar vergeleken in reactie op geselecteerde differentierende rassen van erwt (Pisum sativum) en op enkele andere plantessorten, en in serologische eigenschappen zowel als in deeltjeslengte. Serologisch waren de isolaten niet van elkaar te onderscheiden, wel echter van het verwante bonescherpmozaiekvirus. De voor alle vormen van het laatste virus onvatbare ‘Perfection’-type erwterassen bleken al eerder alle vatbaar te zijn voor het erwterolmozaiekvirus. Ook verschillen de isolaten niet in deeltjeslengte (750 nm). Bij toetsing in zes verschillende over de wereld verspreide laboratoria bleek de reactie van de differentierende erwterassen te varieren van een snelle, de hele plant dodende necrose (groep I) tot onvatbaarheid (groep V). Ook tussen de virusisolaten bestonden kleine verschillen in reactie. Het Nederlandse isolaat E224 gedroeg zich opvallend mild. Ook in de, directe vergelijkingsproeven op enkele toetsplantesoorten bleken kleine biologische verschillen te bestaan. De geconstateerde verschillen overschrijden echter niet die tussen stammen van eenzelfde virus. Wellicht gaat het bij het optreden van necrose en van zwakke symptomen om genen die het vatbaarheidsgensbm modificeren.