short interfering rna accumulation correlates with host recovery in dna virus-infected hosts, and gene silencing targets specific viral sequences.viruses are both inducers and targets of posttranscriptional gene silencing (ptgs), a natural defense mechanism in plants. here we report molecular evidence of the ability of single-stranded dna (ssdna) viruses to induce ptgs in infected plants irrespective of the severity of or recovery from the symptoms. our results reveal that five distinct species of cassava-infecting geminiviruses were capable of triggering ptgs by producing two classes of virus-specific short interfering rnas (sirnas) of 2 ...200415220420
broad spectrum resistance to ssdna viruses associated with transgene-induced gene silencing in cassava.geminiviruses are ssdna viruses that infect a range of economically important crop species. we have developed a pathogen-derived transgenic approach to generate high levels of resistance against these pathogens in a susceptible cultivar of cassava (manihot esculenta). integration of the ac1 gene (which encodes the replication-associated protein) from african cassava mosaic virus imparted resistance against the homologous virus and provided strong cross-protection against two heterologous species ...200415630623
diversity of begomoviruses associated with mosaic disease of cultivated cassava (manihot esculenta crantz) and its wild relative (manihot glaziovii mull. arg.) in uganda.cassava (manihot esculenta) growing in uganda during 2001-2002 has been screened for the presence of begomoviruses using pcr-rflp, cloning full-length genomic components and nucleotide sequence analysis. in contrast with a recent survey in neighbouring kenya, which identified three distinct strains of east african cassava mosaic virus (eacmv, eacmv-ug and eacmv-ke2) as well as east african cassava mosaic zanzibar virus and the new species east african cassava mosaic kenya virus, only eacmv-ug an ...200818559947
quantification of african cassava mosaic virus (acmv) and east african cassava mosaic virus (eacmv-ug) in single and mixed infected cassava (manihot esculenta crantz) using quantitative pcr.the quantity of genomic dna-a and dna-b of african cassava mosaic virus (acmv) and east african cassava mosaic virus uganda (uganda variant, eacmv-ug) was analysed using quantitative pcr to assess virus concentrations in plants from susceptible and tolerant cultivars. the concentrations of genome components in absolute and relative quantification experiments in single and mixed viral infections were determined. virus concentration was much higher in symptomatic leaf tissues compared to non-sympt ...201626456453
a rapid virus-induced gene silencing (vigs) method for assessing resistance and susceptibility to cassava mosaic disease.cassava mosaic disease (cmd) is a major constraint to cassava production in sub-saharan africa. under field conditions, evaluation for resistance to cmd takes 12-18 months, often conducted across multiple years and locations under pressure from whitefly-mediated transmission. under greenhouse or laboratory settings, evaluation for resistance or susceptibility to cmd involves transmission of the causal viruses from an infected source to healthy plants through grafting, or by using agrobacterium-m ...201728270156
east african cassava mosaic-like viruses from africa to indian ocean islands: molecular diversity, evolutionary history and geographical dissemination of a bipartite begomovirus.cassava (manihot esculenta) is a major food source for over 200 million sub-saharan africans. unfortunately, its cultivation is severely hampered by cassava mosaic disease (cmd). caused by a complex of bipartite cassava mosaic geminiviruses (cmg) species (family: geminivirideae; genus: begomovirus) cmd has been widely described throughout africa and it is apparent that cmg's are expanding their geographical distribution. determining where and when cmg movements have occurred could help curtail i ...201223186303
high-throughput multiplex real-time pcr assay for the simultaneous quantification of dna and rna viruses infecting cassava develop a multiplex taqman-based real-time pcr assay (qpcr) for the simultaneous detection and quantification of both rna and dna viruses affecting cassava (manihot esculenta) in eastern africa.201626743662
multiplex rt-pcr assays for the simultaneous detection of both rna and dna viruses infecting cassava and the common occurrence of mixed infections by two cassava brown streak viruses in east africa.uniplex and multiplex reverse transcription-polymerase chain reaction (rt-pcr) protocols were developed for the detection of cassava brown streak viruses (cbsvs) in single and mixed infections with cassava mosaic begomoviruses (cmbs) in a tropical crop plant, cassava (manihot esculenta). cmbs contain ssdna as their genome (genus begomovirus, family geminiviridae) while cbsvs are made up of positive sense ssrna (genus ipomovirus, family potyviridae), and they cause the economically important cass ...201222080852
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