Occurrence and diagnosis of Tomato chlorosis virus in Portugal

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