Occurrence and diagnosis of Tomato chlorosis virus in Portugal

Tomato chlorosis virus (ToCV), a new whitefly-transmitted and phloem-limited Crinivirus infecting tomatoes in Europe, is reported for the first time in Portugal. Tomato plants with symptoms of interveinal chlorosis, collected during autumn 1998 and summer and autumn 1999 in Algarve, southern Portugal, were positive in RT-PCR assays using ToCV-specific primers. The amplified 439 bp fragment was sequenced and showed 99% homology with the ToCV sequence in the GenBank database. A digoxigenin-DNA probe was produced and tested in dot-blot with total RNAs extracted from tomato samples. Both the RT-PCR and dot-blot hybridisation procedures enabled rapid and reliable detection of ToCV from field samples.