Phylogeographic analysis of the full genome of Sweepovirus to trace virus dispersal and introduction to Korea

Sweet potato viromes in eight different geographical regions in Korea and two different cultivars

The sweet potato in the family Convolvulaceae is a dicotyledonous perennial plant. Here, we conducted a comprehensive sweet potato virome study using 10 different libraries from eight regions in Korea and two different sweet potato cultivars by RNA-Sequencing. Comprehensive bioinformatics analyses revealed 10 different virus species infecting sweet potato. Moreover, we identified two novel viruses infecting sweet potato referred to as Sweet potato virus E (SPVE) in the genus Potyvirus and Sweet potato virus F (SPVF) in the genus Carlavirus. Of the identified viruses, Sweet potato feathery mottle virus (SPFMV) was the dominant virus followed by Sweet potato virus C (SPVC) and SPVE in Korea. We obtained a total of 30 viral genomes for eight viruses. Our phylogenetic analyses showed many potyvirus isolates are highly correlated with geographical regions. However, two isolates of SPFMV and a single isolate of Sweet potato virus G (SPVG) were genetically distant from other known isolates. The mutation rate was the highest in SPFMV followed by SPVC and SPVG. Two different sweet potato cultivars, Beni Haruka and Hogammi, were infected by seven and five viruses, respectively. Taken together, we provide a complete list of viruses infecting sweet potato in Korea and diagnostic methods.