Molecular characterization of Alphanecrovirus nicotianae variants identified in sugarbeet

Sugarbeet is a major crop that provides ~ 20% of global sucrose.Viral diseases affecting sugarbeet impact sugar yield and lead to significant financial losses for growers.Recently, our laboratory identified a new Alphanecrovirus nicotianae variant named Beta vulgaris Alphanecrovirus-1 (BvANV-1) in rhizomania-diseased sugarbeet roots.From the latter, two DNA-based clones were developed (WT: wild-type and #7) to determine the impact of the BvANV-1 on the sugarbeet crop 1 .The Alphanecrovirus genus belongs to the Tombusviridae family and consists of four viruses: A. oleae, A. tessellati, A. solani, and A. nicotianae, which are transmitted through the soil by the fungus Olpidium brassicae and/or O. virulentus 2,3 .The Alphanecrovirus genome (~3700 nt) is a positive-sense single-stranded RNA without a 5'-CAP or a 3'-polyA tail.This RNA contains five ORFs, two involved with replication (p23 and p52), two implicated in cell-to-cell movement (p8 and p6), and one involved with encapsidation, viral longdistance movement, and vector transmission (p30) 4,5 .Based on phylogenetic analysis, BvANV-1 is closely related to A. nicotianae compared to other Alphanecrovirus species 6 .Therefore, A. nicotianae will be used as a control in this study.