برخی خصوصیات مولکولی جدایه‌های ایرانی ویروس سوختگی سیاه چغندرقند

Beet black scorch virus (BBSV) infection has been reported from several sugar beet production regions of Iran. In this study, partial molecular properties of some Iranian isolates of BBSV from Azarbaijan-e-Gharbei, Isfahan, Khorasan-e-Razavei, Kermanshah and Fars provinces were determined. Coat protein (CP) gene of three BNYVV isolates and about one third of the genomic 3’ end of four BBSV isolates were amplified by specific primers using RT-PCR method and their nucleotide (nt) sequence were determined. Nucleotide similarity of CP gene among Iranian BNYVV ranged from 97.7 to 100%. BNYVV isolates obtained in this study showed the highest nt similarity (99.6%) with IR-GR1 isolate (FM210683) and the lowest nt similarity (97.7%) with Malr isolate (AF522462) from type B. Iranian BNYVV isolates showed highest similarity with Bao isolate (EF473093) from China in A(P) type. BBSV isolates grouped in two main GI and GII groups based on the CP and 3’UTR sequences. Most Iranian BBSV isolates including four BBSV isolates obtained in this study, clustered in subgroups IA and IB of the main group GI, whereas, the other four isolates from Kermanshah province, together with Chinese isolates clustered in GII group. The highest variation of BBSV isolates have been determined in GII group particularly among BBSV isolates from West Iran, in IIC subgroup. It seems that incidence of these main infection sources and then, their coinfections in East and Central Asia (Mid Asia) including Iran, have been occurred many years before cultivation of sugar beet. In this way, populations of BBSV have been emerged after various bottleneck events from different hosts in the course of time.