High similarity among the tomato yellow leaf curl virus isolates from the west Mediterranean basin: the nucleotide sequence of an infectious clone from Spain.

An isolate of tomato yellow leaf curl geminivirus, from the first epidemic outbreaks that occurred in Murcia, Spain (TYLCV-M) in 1992, was cloned and its nucleotide sequence was determined. The circular single stranded DNA consisted of 2777 nucleotides. The genome organization resembled that of other TYLCV sequenced so far; regulatory signal sequences for bidirectional transcription and for polyadenylation of the transcripts were localized in the sequence. Infectivity of the cloned DNA was demonstrated by subcloning a 1.8 mer of TYLCV-M in pBin19 and agroinoculating it into tomato and Nicotiana benthamiana plants. Symptoms and viral DNA forms in agroinfected plants did not differ from those of field infected ones. Sequence comparisons with other TYLCV isolates show a high homogeneity between isolates from the West Mediterranean Basin, suggesting the presence of a geographical cluster.