Browsing by Author "Mollel, Happyness G."

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    African Basil (Ocimum gratissimum) Is a Reservoir of Divergent Begomoviruses in Uganda
    (Plant disease, 2020) Mollel, Happyness G.; Ndunguru, Joseph; Sseruwagi, Peter; Alicai, Titus; Colvin, John; Navas-Castillo, Jesus; Fiallo-Oliv, Elvira
    Begomoviruses are plant viruses that cause major losses to many economically important crops. Although they are poorly understood, begomoviruses infecting wild plants may have an important role as reservoirs in the epidemiology of viral diseases. This study reports the discovery and genomic characterization of three novel bipartite begomoviruses from wild and cultivated African basil (Ocimum gratissimum) plants collected in Uganda, East Africa. Based on the symptoms shown by the infected plants, the names proposed for these viruses are Ocimum yellow vein virus (OcYVV), Ocimum mosaic virus (OcMV), and Ocimum golden mosaic virus (OcGMV). Genome and phylogenetic analyses suggest that DNA-A of OcGMV is mostly related to begomoviruses infecting tomato in Africa, whereas those of OcYVV and OcMV are closely related to one another and highly divergent within the Old World begomoviruses. The DNA-A of all characterized begomovirus isolates are of a recombinant nature, revealing the role of recombination in the evolution of these begomoviruses. The viruses characterized here are the first identified in O. gratissimum and the first in Ocimum spp. in the African continent and could have important epidemiological consequences for cultivated basils and other important crops.
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    Desmodium mottle virus, the first legumovirus (genus Begomovirus) from East Africa
    (Archives of virology, 2017) Mollel, Happyness G.; Sseruwagi, Peter; Ndunguru, Joseph; Alicai, Titus; Colvin, John; Navas-Castillo, Jesu´ s; Fiallo-Olive, Elvira
    A novel bipartite legumovirus (genus Begomovirus, family Geminiviridae), that naturally infects the wild leguminous plant Desmodium sp. in Uganda, was molecularly characterized and named Desmodium mottle virus. The highest nucleotide identities for DNA-A, obtained from two field-collected samples, were 79.9% and 80.1% with the legumovirus, soybean mild mottle virus. DNA-B had the highest nucleotide identities (65.4% and 66.4%) with a typical non-legumovirus Old World begomovirus, African cassava mosaic virus. This is the first report of a legumovirus in East Africa and extends the known diversity of begomoviruses found infecting wild plants in this continent.
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    A novel East African monopartite begomovirus-betasatellite complex that infects Vernonia amygdalina
    (Archives of virology, 2017) Mollel, Happyness G.; Ndunguru, Joseph; Sseruwagi, Peter; Alicai, Titus; Colvin, John; Navas-Castillo, Jesu´ s; Fiallo-Olive, Elvira
    The complete genomes of a monopartite begomovirus (genus Begomovirus, family Geminiviridae) and an associated betasatellite found infecting Vernonia amygdalina Delile (family Compositae) in Uganda were cloned and sequenced. Begomoviruses isolated from two samples showed the highest nucleotide sequence identity (73.1% and 73.2%) to an isolate of the monopartite begomovirus tomato leaf curl Vietnam virus, and betasatellites from the same samples exhibited the highest nucleotide sequence identity (67.1% and 68.2%) to vernonia yellow vein Fujian betasatellite. Following the current taxonomic criteria for begomovirus species demarcation, the isolates sequenced here represent a novel begomovirus species. Based on symptoms observed in the field, we propose the name vernonia crinkle virus (VeCrV) for this novel begomovirus and vernonia crinkle betasatellite (VeCrB) for the associated betasatellite. This is the first report of a monopartite begomovirus-betasatellite complex from Uganda.