Sweet potato leaf curl disease (SPlcD) was primarily identified in sweet potato fields in korea in 2003, and the complete genomic sequence of sweet potato leaf curl virus (SPlcv) has been cloned. The genome of the korean SPlcv isolate (SPlcv-kr) comprises 2,828 nucleotides with six open reading frames in DnA-A, similar to a monopartite begomovirus. Additionally, neither the genome B genomic component nor the DnA beta sequence was detected. The results of phylogenetic analysis using the maximum parsimony method showed that SPlcv-kr is more closely related to SPlcv-uS (uS) than SPlcv-cn (china) and SPlcv-JP (Japan). A tandem repeat dimer of SPlcv-kr was cloned and found to be infectious in sweet potatoes (Ipomoea batatas) via biolistic inoculation. The SPlcv-infected sweet potatoes exhibited mild leaf curl symptoms of SPlcD, and the newly-replicated viral DnA was detected via Southern blot analysis. results of biotic, molecular, and phylogenetic characterization suggest that SPlcv-kr is a new strain of SPlcv and is importantly placed in the evolutionary progression from curtoviruses to begomoviruses.

Summary. -The complete DNA genome of sweet potato leaf curl virus (SPLCV) from samples obtained from eight regions was amplified by PCR and characterized in this study. The DNA genome of one group (SPLCV Korea group 1) consisted of 2828 nucleotides and that of the second group (SPLCV Korea group 2) consisted of 2829 nucleotides. Sequence comparisons showed that the genome sequences of SPLCV Korea isolates were closely related to those of SPLCV Brazil isolates (FJ969834, FJ969835, and FJ969836), SPLCV Japan isolate (AB433788), and SPLCV USA isolate (AF104036) with nucleotide sequence identity values ranging from 96-98%. Analysis of the phylogenetic relationship of SPLCV Korea isolates with other begomoviruses revealed that the majority of SPLCV Korea isolates were clustered with SPLCV Brazil isolates (FJ969834, FJ969835, and FJ969836). Recombination analysis results revealed three recombinations among SPLCV Korea isolates, SPLCV isolates from Brazil and Japan, and ipomoea yellow vein virus (IYVV) Italy isolate.Keywords: begomovirus; Korea; molecular phylogeny; recombination; sweet potato leaf curl virus (SPLCV) * Corresponding authors. E-mail: cell4u@skku.edu, hschoi@korea. kr; fax: +82-31-290-7870, +82-31-290-0438. Abbreviations: IYVV = ipomoea yellow vein virus; REn = replication enhancer protein; Rep = replication-associated protein; SPLCV = sweet potato leaf curl virus; SPLCGV = sweet potato leaf curl Georgia virus; SPLCCaV = sweet potato leaf curl Canary virus; SPLCLaV = sweet potato leaf curl Lanzarote virus; SPLCESV = sweet potato leaf curl Spain virus; SPGVaV = sweet potato golden veinassociated virus; SPMaV = sweet potato mosaic-associated virus; TbLCV = tobacco leaf curl virus; TrAP = transcriptional activator protein; TYLCV = tomato yellow leaf curl virus