First report of Turnip mosaic virus on Brassicaceae crops in Turkey

During winter and early spring of 2004-2006, Brassicaceae crops, Brassica oleracea, Raphanus sativus and R. raphanistrum, showing mosaic, mottling, necrotic spots, malformation and chlorosis were collected from Canakkale, Balikesir and Bursa Province of the Turkey (Fig. 1 & 2). Leaf samples were tested for the presence of Turnip mosaic virus (TuMV) by DAS-ELISA using a commercial polyclonal antibody (PAb) (Loewe, Germany). Sixteen out of 130 leaf samples from B. oleracea vars. capitata and gemmifera, Raphanus sativus, R. raphanistrum were found to be infected with TuMV, whereas no samples of B. oleracea var. botrytis were found to be infected. Leaf extracts of plants that reacted positively with the TuMV PAb were used for mechanical inoculation and produced chlorotic local lesions on Chenopodium quinoa, severe mosaic and stunting on B .rapa, and mosaic and wilting on Nicotiana benthamiana. These symptoms were similar to those described previously for TuMV (Ohshima et al., 2002; Provvidenti, 1996). In addition, reverse transcription-polymerase chain reaction of total RNA extracted from the inoculated leaves using TuMV-specific primers resulted in the amplification of one fragment of the expected sizes (data not shown).

TuMV belongs to the genus Potyvirus (family Potyviridae), has a single-stranded, positive-sense RNA genome and infects a wide range of plant species, mostly from the family Brassicaceae. It is probably the most widespread and important virus infecting both crop and ornamental species of this family (Ohshima et al., 2002; Provvidenti, 1996; Walsh & Jenner, 2002). TuMV has been reported to occur in the temperate and sub-tropical regions of Africa, Asia, the Americas, Oceania and Europe, including Greece (Tomimura et al., 2004). To our knowledge, this is the first report of the natural occurrence of TuMV on B. oleracea, R. sativus and R. raphanistrum in Turkey.