detection of types of beet necrotic yellow vein benyvirus (bnyvv), causal agent of rhizomania in chenaran region

beet necrotic yellow vein benivirus (bnyvv) as one of the most important virues of sugar beet is the causal agent of rhizomania. bnyvv, as a type member of genus benyvirus has four types a, b, p and j, that are restricted to specific geographic areas. types a and b are similar in pathogenicity, but p and j types that have rna5 are more aggressive. these types cannot be distinguished serologically. for detection of bnyvv types in chenaran region, 28 samples of sugar beet roots showing the suspicious symptoms of rhizomania were collected from vicinity of chenaran sugar factory during growing season in 2006. at first, bnyvv was detected in the samples by das-elisa and rt-pcr. virus type was determined in the infected plants by specific primers and rt-pcr from 28 examined samples, bnyvv was detected  in 23 and 25 samples by elisa and rt-pcr, respectively. rt-pcr using specific primers of virus type produced only a specific band sized 324 bp, therefore, only type a of bnyvv was detected in the infected samples.