The widespread occurrences of Beet soil borne virus and RNA-5 containing Beet necrotic yellow vein virus isolates in sugar beet production areas in Turkey

A total of 632 soil samples were collected from different sugar beet fields in 32 provinces during 2005, 2010 and 2011 growing seasons. Incidences of Beet necrotic yellow vein virus (BNYVV), Beet soil-borne virus (BSBV) and their vector Polymyxa betae were determined by bait plant tests using ELISA and root staining techniques. The percentages of BNYVV and BSBV infested soil samples were 38 and 49.8 %, respectively. The study showed that P. betae was very common (87.7 %) in the sampled sugar beet fields. Additionally, the presence of BNYVV RNA-5 component was investigated by RT-PCR using the primers specific for p26 coding region. Out of 240 BNYVV-infected samples, 85 were selected according to their geographic origin, and 62.4 % of them belonging to 29 provinces were found to contain the RNA-5 segment. The partial nucleotide sequences of RNA-5 of BNYVV isolates from Igdir, Edirne, Ankara and Konya provinces of Turkey were obtained. Nucleotide sequencing and phylogenetic analyses showed that RNA-5 of Turkish BNYVV isolates is closer to the J type BNYVV isolates than the P type isolates. These results also indicated that BNYVV populations containing RNA-5 is highly widespread in sugar beet production areas in Turkey.