First Report of a Novel Potyvirus from Florida Causing Chlorotic Mottling in Squash (Cucurbita pepo).

摘要

During the 2010 to 2011 growing seasons, nine cucurbit leaf samples including cantaloupe, cucumber, pumpkin, squash, and watermelon, showing mosaic and mottling, were collected from fields in the Homestead and Tampa areas in Florida (1). Eight of the nine samples were positive by dot-immunobinding assay (DIBA) and reverse transcription (RT)-PCR for either Watermelon mosaic virus (WMV), Papaya ringspot virus (PRSV-W), or mixed infection of both viruses. One squash sample from the Homestead area showing unique symptoms including chlorotic spots, yellowing, mottling, vein clearing, and mild mosaic was negative by RT-PCR against PRSV-W, Squash vein yellowing virus (SqVYV), WMV, and Zucchini yellow mosaic virus (ZYMV).The presence of virus-like particles (VLP) from symptomatic squash leaves (1) was prepared as described previously (2). Typical potyvirus-like particles ~700 nm long and 12 to 14 nm wide were observed by electron microscope from VLP preparations. Analysis of VLP on SDS-PAGE demonstrated a slightly larger coat protein (CP) (37 kDa compared with PRSV-W [35 kDa]).