Characterization of infectious transcripts from a potato virus X cDNA clone.

A full-length cDNA clone of potato virus X (PVX) has been constructed and fused to the bacteriophage T7 promoter in an in vitro transcription vector. Transcripts derived from this template (pMON 8660) were infectious when inoculated onto the local lesion host, Chenopodium amaranticolor. The infectivity of these transcripts was approximately 0.2% that of authentic PVX RNA. Lesions sampled from plants inoculated with these transcripts contained virus particles and virus aggregates typically observed in lesions from plants inoculated with authentic PVX RNA, as evidenced by electron microscopy. In addition, progeny virus isolated from these lesions was as infectious as progeny virus from an authentic PVX RNA infection when inoculated onto new local lesions plants. Infectious transcripts derived from PVX cDNA clones will facilitate analysis of the molecular aspects of PVX infection.