Watermelon mosaic virus 1 and 2 in Queensland cucurbit crops

Abstract

Watermelon mosaic virus type 1 (WMV-1) has not previously been reported from Australia and has become prevalent in Queensland only since 1970. Watermelon mosaic virus type 2 (WMV-2) continues to reach a high incidence in marrow (Cucurbita pepo) and pumpkin (Cucurbita maxima and Cucurbita moschata) crops, WMV-2 is rarely isolated from watermelons (Citrullus vulgaris) in which epidemics of WMV-1 now cause serious reductions in yield. The Queensland Blue cultivar of C. maxima, the most important cucurbit crop, produces severely distorted fruit following infection by WMV-1, although it is little affected by WMV-2. Physical properties of these WMV isolates and electron microscopic examination of the virus particles and associated cellular inclusions showed them to be similar to those reported elsewhere, but there were some distinctive host reactions for the WMV-2 isolates. No resistance to either WMV-1 or WMV-2 was found in commercially available C. pepo, C. maxima or C. vulgaris. The resistance of Cucumis metuliferus to Australian WMV-1 isolates was confirmed, and a source of resistance to both WMV-1 and WMV-2 was found in Lagenaria siceravia. Methods of separation of WMV-1 and WMV-2 from mixed isolates and methods for the identification of each on differential hosts and by serology were shown to be effective.

The N and C Termini of the Coat Proteins of Potyviruses Are Surface-located and the N Terminus Contains the Major Virus-specific Epitopes

“…Potyviruses used in this study were bean yellow mosaic virus (BYMV-S; Randles et al, 1980), clover yellow vein virus (CYVV; Garrett, 1983), Johnson grass mosaic virus (JGMV; Shukla et al, 1987), passion-fruit woodiness virus (PWV-Tip blight; Shukla et al, 1988), potato virus Y (PVY-D; Shukla et al, 1986) and watermelon mosaic virus II (WMMV-II; Greber, 1978). Propagation hosts were Phaseolus vulgaris for BYMV, CYVV and PWV, Zea mays cv.…”

Carrot as a natural host ofWatermelon mosaic virus

“…The latter was detected from only one location in one sample . A possible reason for this is that WMV is endemic in southern Queensland (Greber 1978) and infects almost all cucurbit species, thus providing a greater inoculum source. In contrast, CarVY has a very limited host range within Apiaceae and carrots are not grown commercially in the region during the hot summer months.…”

The Use of 3' Non-coding Nucleotide Sequences in the Taxonomy of Potyviruses: Application to Watermelon Mosaic Virus 2 and Soybean Mosaic Virus-N

“…The WMV 2 isolate was originally obtained from Mr R. S. Greber (Greber, 1978) and was maintained and propagated in marrow and purified according to methods described previously .…”