The 2b protein encoded by Cucumber mosaic virus (CMV) has been shown to be a silencing suppressor and pathogenicity determinant in solanaceous hosts, but a movement determinant in cucumber. In addition, synergistic interactions between CMV and Zucchini yellow mosaic virus (ZYMV) have been described in several cucurbit species. Here, it was shown that deletion of the 2b gene from CMV prevented e...

During routine graft indexing of Rubus clones at the USDA-ARS Horticultural Crops Research Laboratory in Corvallis, Oregon, a ‘Glen Clova’ plant that originated in Scotland induced severe symptoms including stunting and apical necrosis when grafted on ‘Munger’ black raspberry (Rubus occidentalis). Cloning of viral dsRNA obtained from the plant and sequence analysis indicated the presence of a n...

In order to understand the molecular mechanisms underlying circulative transmission of potato leafroll virus (PLRV) by aphids, we screened Myzus persicae proteins as putative PLRV binding molecules using a virus overlay assay of protein blots. In this way, we found that purified PLRV particles exhibited affinity for five aphid proteins. The one most readily detected has an M(r) of 63K, and was ...

In minor veins of leaves of Beta vulgaris L. (sugar beet) yellows virus particles were found both in parenchyma cells and in mature sieve elements. In parenchyma cells the particles were usually confined to the cytoplasm, that is, they were absent from the vacuoles. In the sieve elements, which at maturity have no vacuoles, the particles were scattered throughout the cell. In dense aggregations...

Potato leafroll virus (PLRV) is transmitted by aphids in a persistent manner. Although virus circulation within the aphid leading to transmission has been well characterized, the mechanisms involved in virus recognition at aphid membranes are still poorly understood. One isolate in our collection (PLRV-14.2) has been shown to be non- or only poorly transmitted by some clones of aphids belonging...

Drought is a major threat to crop production worldwide and is accentuated by global warming. Plant responses to this abiotic stress involve physiological changes overlapping, at least partially, the defense pathways elicited both by viruses and their herbivore vectors. Recently, a number of theoretical and empirical studies anticipated the influence of climate changes on vector-borne viruses of...

Amino acids near the N terminus of the coat protein of tobacco vein mottling virus were deleted or altered by site-directed mutagenesis to determine the effect on aphid transmissibility of the virus. Deletion of a three amino acid sequence Asp-Ala-Gly, which is conserved in aphid-transmissible potyvirus isolates, abolished transmission. The mutation Ala----Thr in this triplet drastically reduce...