Since 1988, a yellowing disease of melon, cucumber and zucchini squash has been frequently observed in summer autumn crops France. Infected plants show thickening the older leaves; symptom intensity differs depending upon cultivar season, can be easily overlooked when are already infected by mosaic‐inducing viruses or other pathogens. The is associated with presence virus spherical particles c. 25 nm diameter, which readily transmitted persistent manner aphids Myzus persicae Aphis gossypii ,...

Beet western yellows luteovirus, like other luteoviruses, cannot be transmitted to host plants by mechanical inoculation but requires an aphid vector, a feature that has heretofore presented serious obstacle the study of such viruses. In this paper we describe use agroinfection infect hosts with beet virus without recourse aphids. Agroinfection is procedure for introducing plant into via Agrobacterium tumefaciens harboring Ti plasmid, which can efficiently transfer portion plasmid (T-DNA)...

Aphid transmission of poleroviruses is highly specific, but the viral determinants governing this specificity are unknown. We used a gene exchange strategy between two with different vectors, Beet western yellows virus (BWYV) and Cucurbit aphid-borne (CABYV), to analyze role major minor capsid proteins in vector specificity. Virus recombinants obtained by exchanging sequence readthrough domain (RTD) viruses replicated plant protoplasts whole plants. The hybrid protein chimeric was...

Previous studies have revealed a wide-spread occurence of the partial and complete genomes reverse-transcribing pararetroviruses in nuclear herbaceous plants. Although absence virus-encoded integrases attests to random incidental incorporation viral sequences, their presence could functional implications for virus-host interactions.

ABSTRACT Point mutations were introduced into or near five conserved sequence motifs of the readthrough domain beet western yellows virus minor capsid protein P74. The mutant was tested for its ability to accumulate efficiently in agroinfected plants and be transmitted by aphid vector, Myzus persicae . stability mutants aphid-infected followed analysis progeny virus. Only mutation Y201D found strongly inhibit accumulation planta following agroinfection, but high levels restored reversion...

SUMMARY Taxonomy: There are three members of the genus Polerovirus (family Luteoviridae ) that induce yellowing sugar beet: Beet mild virus (BMYV), chlorosis (BChV) and western yellows ‐USA (BWYV‐USA, Fig. 1 ). Non‐beet‐infecting isolates BWYV found particularly within Europe have now been re‐named Turnip (TuYV). Species‐specific antibodies unavailable, but viruses can be distinguished by RT‐PCR using primers specifically designed to 5′ end their respective genomes. Taxonomy genome...

Beet western yellows virus (BWYV), family Luteoviridae , is an icosahedral plant which strictly transmitted by aphids in a persistent and circulative manner. Virions cross two cellular barriers the aphid receptor-based mechanisms involving endocytosis exocytosis. Particles are first transported across intestinal cells into haemolymph then accessory salivary gland for delivery to via saliva. We identified midgut part of digestive tract as site passage BWYV virions. To analyse role...

Yellowing diseases of sugar beet can be caused by a range strains classified as Beet mild yellowing virus (BMYV) or western yellows (BWYV), both belonging to the genus Polerovirus family Luteoviridae. Host range, genomic, and serological studies have shown that isolates these viruses grouped into three distinct species. Within species, coat protein amino acid sequences are highly conserved (more than 90% homology), whereas P0 (open reading frame, ORF 0) variable (about 30% homology). Based...

Summary In order to discriminate between sugar beet infecting mild yellowing virus (BMYV) and other isolates of western yellows (BWYV), monoclonal antibodies (MAbs) radioactive riboprobes were used. With MAbs prepared against BMYV or potato leafroll (PLRV) no distinction could be established BWYV. Seven probes synthesised from a lettuce BWYV isolate; their localisation in the genome is known they cover almost its entire length. Probes ′3 part hybridised with all whereas those ′5 did not...

Soft scales nymphs are suspected to propagate grapevine leafroll viruses in the vineyard, while moving from vine vine, but results of long distance dispersion, especially those due wind, poorly known. Thus, a net sticky cylindrical traps was placed newly planted plot evaluate aerial dispersal Parthenolecanium corni (Hemiptera Coccidae) nymphs. The surrounded by plots infested this species. Number crawlers collected on generally higher trap side exposed downwind and depended population...

Abstract Mealybugs (Hemiptera: Pseudococcidae) are important pests for crops worldwide. Different species, cryptic taxa under the same species name or even populations within a can differ in biological characteristics, such as phenology, resistance to insecticides, virus transmission and susceptibility natural enemies. Therefore, their management efficacy depends on accurate identification. Microsatellite genetic markers efficient revealing fine-scale taxonomic status of insects, both at...

Distribution patterns of the European fruit lecanium Parthenolecanium corni (Bouché) and grapevine leafroll-associated virus-1 (GLRaV-1) virus A (GVA) were monitored from 2003 to 2015 in a Riesling vine plot northeast France. Virus spread was compared between two periods: 2003–2008 2009–2014. The percentage infected vines increased 54 78% for GLRaV-1 14 26% GVA. spatial distribution viruses P. analysed using permutation tests revealed an aggregative pattern. not associated with density...

The cottony grape scale Pulvinaria vitis is a insect colonizing grapevine; however, its capacity as vector of grapevine viruses poorly known in comparison to other species that are vectors viral the genera Ampelovirus and Vitivirus. ability P. transmit ampeloviruses Grapevine leafroll-associated [GLRaV]-1, -3, -4, vitivirus virus A (GVA), healthy vine cuttings was assessed. insects used originated from commercial plots located Alsace, Eastern France. When nymphs sampled leafroll-infected...

Grapevine-infecting ampelo- and vitiviruses are transmitted by scale insects belonging to several species, among which is the European fruit lecanium, Parthenolecanium corni (Bouché) (Hemiptera Coccidae). Our objective was characterize transmission biology of grapevine leafroll-associated viruses (GLRaV) virus A (GVA) this soft species in order evaluate its ability spread these viruses. In experiments with nymphs sampled from different vineyards infected GLRaV 1, 2, 3 GVA, P. only 1 GVA...

SUMMARY The effect of dodecanoic acid, a behaviour‐controlling chemical which alters aphid feeding behaviour and virus transmission efficiency, was studied under field conditions. In first experiment, acid reduced the level natural colonisation sugar beet by Aphis fabae. A second experiment revealed no significant influence on secondary spread semi‐persistent yellows persistent mild yellowing virus.