Genetic diversity and distribution of Beet black scorch virus in Iran

Beet black scorch virus(BBSV) is a new soil-borne virus reported from sugar beet fields around the world that in terms of having similar symptoms (root beard) with Beet necrotic yellow vein virus and Probably some mutual interaction with that has high economic importance. For investigation of BBSV distribution in Iran's sugar beet farms a total of 309 samples were collected. Evaluation of test samples with RT-PCR indicated that 147 sample in total (48%) are infected. BBSV also has a satellite that in 30 cases (10%) of the samples was detected. According to this BBSV were detected in sugar beet farms of Khorasan Razavi, North Khorasan, South Khorasan, Lorestan, Ardabil, East Azarbayjan, West Azarbayjan, Ghazvin, Hamedan, Kerman, Kermanshah and Zanjan Provinces. Five isolates for assessment of genetic diversity were selected based on geographical distribution and symptoms in greenhouse including West Azarbayjan, Hamedan, Khorasan Razavi(Mashhad), North Khorasan(shirvan) and Kermanshah. Two important parts including Coat protein and 3'UTR of these isolates were compared with Chinese –N and US –Co isolates. Sequence analysis indicated that Us and Chinese isolates are more resemble together than to Iranians. Resemblance of Iranian isolates to Chinese and US isolates were about 88% in both parts. Iranian isolates were resemble together 98-99%. Only North Khorasan (Shirvan) isolate with less identical batch was separated. It seems that differences in 3'UTR are not effective and in all isolates virus genome well-expressed and translated. But amino acid changes in CP specially N-terminal area are effective in symptoms inducing and interaction with other soil-born Vieruses.