Characterization of a variant isolate of Zucchini yellow mosaic virus infecting green kabocha (Cucurbita maxima L.) in Bogor, Indonesia

Abstract

Zucchini yellow mosaic virus (ZYMV) has been reported in Indonesia over the past decade. However, the biological, morphological, and molecular characterizations of Indonesian isolates of this virus have not yet been determined. In this study, we report a ZYMV isolate infecting green kabocha (Cucurbita maxima L.; GK) and exhibiting a typical chlorotic mosaic with vein banding symptoms. A bioassay performed on indicator plants demonstrated that the host range of the ZYMV-GK isolate was restricted to Cucurbitaceae, Amaranthaceae, and one Solanaceae family member, Nicotiana benthamiana. Interestingly, Luffa acutangula, a species in the Cucurbitaceae family, could not be infected with ZYMV-GK. Electron microscopy revealed the presence of filamentous virus-like particles, approximately 900 nm in length, characteristic to potyviruses. Sequence analysis of the coat protein gene confirmed that ZYMV-GK was a variant of ZYMV sharing 94.5% (96.7%) maximum nucleotide (amino acid) sequence identity with the GenBank sequence of a Vietnamese isolate (Acc.no. DQ925447.1).