Molecular and Biological Features of Sweet Potato Leaf Curl Virus in Burkina Faso

Abstract

Begomoviruses (family Geminiviridae, genus Begomovirus) that infect sweetpotato (Ipomoea batatas) are known as sweepoviruses and are a major constraint to sweetpotato production. To date, the known distribution of sweepoviruses in Africa has been limited to Kenya, Uganda, South Africa, Sudan and Tanzania. Weeds can act as sources or reservoirs for important crop pathogens, but their role in crop plant diseases in Africa has not been well documented. Begomoviruses infect a wide range of dicotyledonous plants, including cultivated crops and weeds. Sweetpotato plants and weeds from Burkina Faso exhibiting severe leaf curling, suggesting the presence of begomoviruses, were tested and characterized using rolling circle amplification followed by cloning and sequencing. Six full genomes were successfully obtained, and molecular analysis revealed a monopartite genomic organization typical of sweepoviruses. Sequence analyses and phylogenetic data showed the virus was closely related to Sweet potato leaf curl virus-United States (SPLCV-US) with 98% nucleotide identity for sweetpotato plant samples. From Ipomoea alba, the sequenced genomes were also closely related to SPLCV-US with 96% as the highest nucleotide sequence identity. When healthy Ipomoea setosa plants were grafted with infected scions, plants showed systemic upward leaf-curling and leaf deformation symptoms. This is the first published full-length genome of a sweepovirus reported and first time in West Africa that the common weed I alba has been found to be sweepovirus-positive. This discovery raises concerns about its presence in Burkina Faso and its potential spread in the region.