Partial sequence of HSP70 homologue gene shows diversity between West African and East African isolates of sweetpotato chlorotic stunt virus.
Sweetpotato virus disease, caused by infection with both the crinivirus sweetpotato chlorotic stunt virus (SPCSV) and the potyvirus sweetpotato feathery mottle virus, severely reduces yield of sweetpotato in Africa. The SPCSV has been distinguished into two main strains. One of the strains is found in West and the other in East and southern Africa. Nucleic acid from the heat shock protein 70 (HSP70) homologue gene of isolates from Nigeria and Madagascar was partially sequenced. In comparison to previously described sequences of the HSP70 homologue gene of Ugandan isolates, a Madagascan sample had between 2.8% and 3.2% variation at the nucleic acid level and no amino acid variation. In contrast, a Nigerian sample had between 25.8-27% variation at the nucleic acid level and 7.5% variation in amino acids. This indicates that the Madagascan isolate belongs to the East African strain of SPCSV. The EMBL accession numbers of the sequences reported in this study are AJ278650 to AJ278653.