Tomato yellow leaf curl virus and Tomato leaf curl Taiwan virus invade south-east coast of China

An epidemic outbreak of severe yellow leaf curl disease was reported in field grown tomato within Zhejiang Province of China in the autumn-winter cropping season of 2006. A molecular diagnostic survey was carried out based on comparisons of partial and complete viral DNA sequences. Comparison of partial DNA-A sequences amplified with degenerate primers specific for begomoviruses confirmed the presence of two types of begomoviruses. The complete DNA sequences of five isolates, corresponding to the two types, were determined. Sequence comparisons and phylogenetic analysis revealed that they correspond to two previously identified begomoviruses, Tomato yellow leaf curl virus and Tomato leaf curl Taiwan virus. The satellite DNA beta molecule was not detected in these samples by either PCR or Southern blot hybridization analysis. There has been no previous report of geminivirus disease incidence in Zhejiang Province, indicating that the introduction of these two tomato infecting geminiviruses into the agro-ecological zone of South-eastern China is a fairly recent event. The implications for disease control are discussed.