Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| spatial analysis of temporal changes in the pandemic of severe cassava mosaic disease in north-western tanzania. | to improve understanding of the dynamics of the cassava mosaic disease (cmd) pandemic front, geospatial approaches were applied to the analysis of three years' data obtained from a 2° by 2° (ca 222km by 222 km) area of north-western tanzania. a total of 80 farmers' fields were assessed in each of 2009, 2010 and 2011, with 20 evenly-distributed fields per 1° by 1° quadrant. cmd-associated variables (cmd incidence, cmd severity, vector-borne cmd infection and vector abundance) increased in magnitu ... | 2017 | 28714353 |
| near-atomic resolution structure of a plant geminivirus determined by electron cryomicroscopy. | african cassava mosaic virus is a whitefly-transmitted geminivirus which forms unique twin particles of incomplete icosahedra that are joined at five-fold vertices, building an unusual waist. how its 22 capsomers interact within a half-capsid or across the waist is unknown thus far. using electron cryo-microscopy and image processing, we determined the virion structure with a resolution of 4.2 å and built an atomic model for its capsid protein. the inter-capsomer contacts mediated by the flexibl ... | 2017 | 28712809 |
| nitric oxide associated protein 1 is associated with chloroplast perturbation and disease symptoms in nicotiana benthamiana infected with south african cassava mosaic virus. | nitric oxide associated 1 (noa1) in plants is a cyclic gtpase involved in protein translation in the chloroplast and has been indirectly linked to nitric oxide (no) accumulation and response to biotic stress. the association between noa1 and no accumulation in arabidopsis noa1 mutants has been linked to the inability of noa1 mutants to accumulate carbon reserves such as fumarate, leading to chloroplast dysfunction and a pale green leaf phenotype. to understand the role played by noa1 in response ... | 2017 | 28577889 |
| 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 ... | 2017 | 28270156 |
| desmodium mottle virus, the first legumovirus (genus begomovirus) from east africa. | 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 ... | 2017 | 28243802 |
| deinbollia mosaic virus: a novel begomovirus infecting the sapindaceous weed deinbollia borbonica in kenya and tanzania. | four isolates of a bipartite begomovirus from naturally infected deinbollia borbonica plants exhibiting yellow mosaic symptoms in kenya and tanzania were molecularly characterised. the dna-a was most closely related to that of tomato leaf curl mayotte virus (am701764; 82%), while the dna-b shared the highest nucleotide sequence identity with that of east african cassava mosaic virus (aj704953) at 65%. based on the current ictv species demarcation criterion for the genus begomovirus (≥91% sequenc ... | 2017 | 28070648 |
| differential response of cassava genotypes to infection by cassava mosaic geminiviruses. | mitigation of cassava mosaic disease (cmd) focuses on the introgression of resistance imparted by the polygenic recessive (cmd1), dominant monogenic (cmd2) and cmd3 loci. the mechanism(s) of resistance they impart, however, remain unknown. two cmd susceptible and nine cmd resistant cassava genotypes were inoculated by microparticle bombardment with infectious clones of african cassava mosaic virus cameroon strain (acmv-cm) and the kenyan strain k201 of east african cassava mosaic virus (eacmv ke ... | 2017 | 27693919 |
| divergent evolutionary and epidemiological dynamics of cassava mosaic geminiviruses in madagascar. | cassava mosaic disease (cmd) in madagascar is caused by a complex of at least six african cassava mosaic geminivirus (cmg) species. this provides a rare opportunity for a comparative study of the evolutionary and epidemiological dynamics of distinct pathogenic crop-infecting viral species that coexist within the same environment. the genetic and spatial structure of cmg populations in madagascar was studied and bayesian phylogeographic modelling was applied to infer the origins of madagascan cmg ... | 2016 | 27600545 |
| small rna and methylation responses in susceptible and tolerant landraces of cassava infected with south african cassava mosaic virus. | endogenous small rnas (srnas) associated with gene regulatory mechanisms respond to virus infection, and virus-derived small rnas (vsrnas) have been implicated in recovery or symptom remission in some geminivirus-host interactions. transcriptional gene silencing (tgs) (24 nt vsrnas) and post transcriptional gene silencing (ptgs) (21-23 nt vsrnas) have been associated with geminivirus intergenic (ir) and coding regions, respectively. in this illumina deep sequencing study, we compared for the fir ... | 2016 | 27586073 |
| translation, modification and cellular distribution of two ac4 variants of african cassava mosaic virus in yeast and their pathogenic potential in plants. | plant infecting geminiviruses encode a small (a)c4 protein within the open reading frame of the replication-initiator protein. in african cassava mosaic virus, two in-frame start codons may be used for the translation of a longer and a shorter ac4 variant. both were fused to green fluorescent protein or glutathione-s-transferase genes and expressed in fission yeast. the longer variant accumulated in discrete spots in the cytoplasm, whereas the shorter variant localized to the plasma membrane. a ... | 2016 | 27584591 |
| deciphering the biology of deltasatellites from the new world: maintenance by new world begomoviruses and whitefly transmission. | deltasatellites are small noncoding dna satellites associated with begomoviruses. the study presented here has investigated the biology of two deltasatellites found in wild malvaceous plants in the new world (nw). infectious clones of two nw deltasatellites (from malvastrum coromandelianum and sidastrum micranthum) and associated begomoviruses were constructed. infectivity in nicotiana benthamiana and their natural malvaceous hosts was assessed. the nw deltasatellites were not able to spread aut ... | 2016 | 27400152 |
| properties of african cassava mosaic virus capsid protein expressed in fission yeast. | the capsid proteins (cps) of geminiviruses combine multiple functions for packaging the single-stranded viral genome, insect transmission and shuttling between the nucleus and the cytoplasm. african cassava mosaic virus (acmv) cp was expressed in fission yeast, and purified by sds gel electrophoresis. after tryptic digestion of this protein, mass spectrometry covered 85% of the amino acid sequence and detected three n-terminal phosphorylation sites (threonine 12, serines 25 and 62). differential ... | 2016 | 27399762 |
| expression of concern: sequences enhancing cassava mosaic disease symptoms occur in the cassava genome and are associated with south african cassava mosaic virus infection by a. t. maredza, f. allie, g. plata, m. e. c. rey. | 2016 | 27119656 | |
| erratum to: sequences enhancing cassava mosaic disease symptoms occur in the cassava genome and are associated with south african cassava mosaic virus infection. | 2016 | 27013466 | |
| two novel dnas that enhance symptoms and overcome cmd2 resistance to cassava mosaic disease. | cassava mosaic begomoviruses (cmbs) cause cassava mosaic disease (cmd) across africa and the indian subcontinent. like all members of the geminivirus family, cmbs have small, circular single-stranded dna genomes. we report here the discovery of two novel dna sequences, designated segs-1 and segs-2 (forsequencesenhancinggeminivirussymptoms), that enhance symptoms and break resistance to cmd. the segs are characterized by gc-rich regions and the absence of long open reading frames. both segs enhan ... | 2016 | 26865712 |
| high-throughput multiplex real-time pcr assay for the simultaneous quantification of dna and rna viruses infecting cassava plants. | to 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. | 2016 | 26743662 |
| loss of cmd2-mediated resistance to cassava mosaic disease in plants regenerated through somatic embryogenesis. | cassava mosaic disease (cmd) and cassava brown streak disease (cbsd) are the two most important viral diseases affecting cassava production in africa. three sources of resistance are employed to combat cmd: polygenic recessive resistance, termed cmd1, the dominant monogenic type, named cmd2, and the recently characterized cmd3. the farmer-preferred cultivar tme 204 carries inherent resistance to cmd mediated by cmd2, but is highly susceptible to cbsd. selected plants of tme 204 produced for rna ... | 2016 | 26662210 |
| mapping and identification of cassava mosaic geminivirus dna-a and dna-b genome sequences for efficient sirna expression and rnai based virus resistance by transient agro-infiltration studies. | geminiviruses are among the most serious pathogens of many economically important crop plants and rna interference (rnai) is an important strategy for their control. although any fragment of a viral genome can be used to generate a double stranded (ds) rna trigger, the precursor for generation of sirnas, the exact sequence and size requirements for efficient gene silencing and virus resistance have so far not been investigated. previous efforts to control geminiviruses by gene silencing mostly t ... | 2016 | 26581664 |
| 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 ... | 2016 | 26456453 |
| resistance gene analogs involved in tolerant cassava--geminivirus interaction that shows a recovery phenotype. | the current literature describes recovery from virus-induced symptoms as a rna silencing defense, but immunity-related genes, including the structurally specific resistance gene analogs (rgas) that may play a key role in tolerance and recovery is not yet reported. in this study, the transcriptome data of tolerant cassava tme3 (which exhibits a recovery phenotype) and susceptible cassava t200 infected with south african cassava mosaic virus were explored for rgas. putative resistance protein anal ... | 2015 | 26370397 |
| sequences enhancing cassava mosaic disease symptoms occur in the cassava genome and are associated with south african cassava mosaic virus infection. | cassava is an important food security crop in sub-saharan africa. two episomal begomovirus-associated sequences, named sequences enhancing geminivirus symptoms (segs1 and segs2), were identified in field cassava affected by the devastating cassava mosaic disease (cmd). the sequences reportedly exacerbated cmd symptoms in the tolerant cassava landrace tme3, and the model plants arabidopsis thaliana and nicotiana benthamiana, when biolistically co-inoculated with african cassava mosaic virus-camer ... | 2016 | 25920485 |
| form follows function in geminiviral minichromosome architecture. | a comprehensive survey on the viral minichromosomes of the begomoviruses abutilon mosaic virus, tomato yellow leaf curl sardinia virus, african cassava mosaic virus, indian cassava mosaic virus (family geminiviridae) during the course of infections in nicotiana benthamiana is summarized. using optimized one-dimensional and two-dimensional gel systems combined with blot hybridization and a standardized evaluation, discrete and heterogeneous virus-specific signals with different dna forms were com ... | 2015 | 25445344 |
| transcriptional analysis of south african cassava mosaic virus-infected susceptible and tolerant landraces of cassava highlights differences in resistance, basal defense and cell wall associated genes during infection. | cassava mosaic disease is caused by several distinct geminivirus species, including south african cassava mosaic virus-[south africa:99] (sacmv). to date, there is limited gene regulation information on viral stress responses in cassava, and global transcriptome profiling in sacmv-infected cassava represents an important step towards understanding natural host responses to plant geminiviruses. | 2014 | 25412561 |
| evolutionary liberties of the abutilon mosaic virus cluster. | two new strains of abutilon mosaic virus (abmv; geminiviridae) from germany (stuttgart) and france (paris) have been characterized by circomics, direct pyrosequencing of rolling circle amplification (rca) products, as well as conventional cloning and sanger sequencing. rca combined with an analysis of restriction fragment length polymorphisms confirmed the completeness of the sequence determination and a close relationship of both isolates for dna a with 99 % nucleotide sequence identity. phylog ... | 2015 | 25315632 |
| the rxl motif of the african cassava mosaic virus rep protein is necessary for rereplication of yeast dna and viral infection in plants. | geminiviruses, single-stranded dna plant viruses, encode a replication-initiator protein (rep) that is indispensable for virus replication. a potential cyclin interaction motif (rxl) in the sequence of african cassava mosaic virus rep may be an alternative link to cell cycle controls to the known interaction with plant homologs of retinoblastoma protein (prbr). mutation of this motif abrogated rereplication in fission yeast induced by expression of wildtype rep suggesting that rep interacts via ... | 2014 | 24999043 |
| virus versus host plant micrornas: who determines the outcome of the interaction? | considering the importance of micrornas (mirnas) in the regulation of essential processes in plant pathogen interactions, it is not surprising that, while plant mirna sequences counteract viral attack via antiviral rna silencing, viruses in turn have developed antihost defense mechanisms blocking these rna silencing pathways and establish a counter-defense. in the current study, computational and stem-loop reverse transcription - polymerase chain reaction (rt-pcr) approaches were employed to a) ... | 2014 | 24896088 |
| computer analysis identifies sequence homologies between potential gene products of maize streak virus and those of cassava latent virus and tomato golden mosaic virus. | the amino acid sequences of the putative polypeptides of maize streak virus (msv) have been systematically compared with those of cassava latent virus (clv) and tomato golden mosaic virus (tgmv) using the programme diagon (8).conserved sequences have been detected between peptides encoded by the complementary (-) sense of msv and those of clv and tgmv, viz; the 40 200 mr polypeptide of clv-1 (3) and the 40 285 mr polypeptide of tgmv-a (4) show extensive homologies with the 17 768 mr and 31 388 m ... | 1985 | 24306572 |
| cassava latent virus infections mediated by the ti plasmid of agrobacterium tumefaciens containing either monomeric or dimeric viral dna. | plant infections with cassava latent virus (clv) were mediated by the ti plasmid of agrobacterium tumefaciens containing either monomeric or dimeric copies of the virus genome. the clv dnas caused typical symptoms when they were inoculated in agrobacterium strains c58, lba4404 and a vire mutant a1026, but not other agrobacterium strains with mutations in other vir loci or an e. coli pola strain. virus-specific dna forms characteristic of normal clv infections were found after such infection. cha ... | 1988 | 24272630 |
| why mosaic? gene expression profiling of african cassava mosaic virus-infected cassava reveals the effect of chlorophyll degradation on symptom development. | cassava mosaic disease, caused by cassava begomoviruses, is the most serious disease for cassava in africa. however, the pathogenesis of this disease is poorly understood. we employed high throughput digital gene expression profiling based on the illumina solexa sequencing technology to investigate the global transcriptional response of cassava to african cassava mosaic virus infection. we found that 3,210 genes were differentially expressed in virus-infected cassava leaves. gene ontology term a ... | 2014 | 24237761 |
| assessing global transcriptome changes in response to south african cassava mosaic virus [za-99] infection in susceptible arabidopsis thaliana. | in susceptible plant hosts, co-evolution has favoured viral strategies to evade host defenses and utilize resources to their own benefit. the degree of manipulation of host gene expression is dependent on host-virus specificity and certain abiotic factors. in order to gain insight into global transcriptome changes for a geminivirus pathosystem, south african cassava mosaic virus [za:99] and arabidopsis thaliana, 4×44k agilent microarrays were adopted. after normalization, a log2 fold change filt ... | 2013 | 23826319 |
| a geminivirus-satellite complex is associated with leaf deformity of mentha (mint) plants in punjab. | a widespread leaf deformity disease of mentha (mint), accompanied by whiteflies, the vectors of begomoviruses, was observed in punjab in the last few years. the presence of begomovirus was indicated by dna dot-blot analysis using the conserved coat protein and replication-associated protein genes of another begomovirus, sri lankan cassava mosaic virus (slcmv). a dna fragment (2.0 kb), representing a partial genomic dna of a begomovirus, amplified from the symptomatic mentha leaves was used to de ... | 2011 | 23637488 |
| complete genome sequencing of two causative viruses of cassava mosaic disease in ghana. | cassava mosaic disease (cmv), caused by one or a combination of cassava mosaic geminiviruses, is ranked among the most important constraints to profitable and efficient production of cassava. effective control measures require in-depth knowledge of the viral causative agent. using rolling-circle amplification and unique enzymes, the full genome of two species of cassava mosaic geminivirus isolated from infected cassava plants in ghana were cloned into pcambia 1300 and pet-28b. the sequences of t ... | 2012 | 23237086 |
| 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 ... | 2012 | 23186303 |
| [effects of seven rna silencing suppressors on heterologous expression of green fluorescence protein expression mediated by a plant virus-based system in nicotiana benthamiana]. | to test the effects of 7 virus-encoded rna silencing suppressors (rsss) for enhancement of a plant virus-based vector system-mediated heterologous expression of green fluorescence protein (gfp) in nicotiana benthamiana. | 2012 | 23174571 |
| a single-tube duplex and multiplex pcr for simultaneous detection of four cassava mosaic begomovirus species in cassava plants. | a single-tube duplex and multiplex pcr was developed for the simultaneous detection of african cassava mosaic virus (acmv), east african cassava mosaic cameroon virus (eacmcv), east african cassava mosaic malawi virus (eacmmv) and east african cassava mosaic zanzibar virus (eacmzv), four cassava mosaic begomoviruses (cmbs) affecting cassava in sub-saharan africa. co-occurrence of the cmbs in cassava synergistically enhances disease symptoms and complicates their detection and diagnostics. four p ... | 2013 | 23174160 |
| exploiting the combination of natural and genetically engineered resistance to cassava mosaic and cassava brown streak viruses impacting cassava production in africa. | cassava brown streak disease (cbsd) and cassava mosaic disease (cmd) are currently two major viral diseases that severely reduce cassava production in large areas of sub-saharan africa. natural resistance has so far only been reported for cmd in cassava. cbsd is caused by two virus species, cassava brown streak virus (cbsv) and ugandan cassava brown streak virus (ucbsv). a sequence of the cbsv coat protein (cp) highly conserved between the two virus species was used to demonstrate that a cbsv-cp ... | 2012 | 23049780 |
| a melting pot of old world begomoviruses and their satellites infecting a collection of gossypium species in pakistan. | clcud in southern asia is caused by a complex of multiple begomoviruses (whitefly transmitted, single-stranded [ss]dna viruses) in association with a specific ssdna satellite; cotton leaf curl multan betasatellite (clcumub). a further single ssdna molecule, for which the collective name alphasatellites has been proposed, is also frequently associated with begomovirus-betasatellite complexes. multan is in the center of the cotton growing area of pakistan and has seen some of the worst problems ca ... | 2012 | 22899988 |
| construction of effective inverted repeat silencing constructs using sodium bisulfite treatment coupled with strand-specific pcr. | rna silencing has been exploited to produce transgenic plants with resistance to viral pathogens via posttranscriptional gene silencing (ptgs). in some cases, this technology is difficult to apply due to the instability of inverted repeat (ir) constructs during cloning and plant transformation. although such constructs have been shown to be stabilized with introns and efficiently induce rna silencing, we found that the pdk intron did not stabilize south african cassava mosaic virus (sacmv) silen ... | 2012 | 22482441 |
| evolution of african cassava mosaic virus by recombination between bipartite and monopartite begomoviruses. | cassava mosaic disease (cmd) is a major constraint on cassava cultivation in africa. the disease is endemic and is caused by seven distinct cassava mosaic geminiviruses (cmgs), some of them including several variants. | 2012 | 22416906 |
| influence of retinoblastoma-related gene silencing on the initiation of dna replication by african cassava mosaic virus rep in cells of mature leaves in nicotiana benthamiana plants. | abstract: background: geminiviruses mainly infect terminally differentiated tissues and cells in plants. they need to re-programme host cellular machinery for dna replication. this process is thought to be mediated by inactivation of cell-cycle repressor proteins and by induction of host dna synthesis protein expression through actions of the geminviral replication initiator protein (rep). findings: exploiting a nicotiana benthamiana pori2 line, which is transformed with a transgene consisting ... | 2011 | 22204717 |
| 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 ... | 2012 | 22080852 |
| top 10 plant viruses in molecular plant pathology. | many scientists, if not all, feel that their particular plant virus should appear in any list of the most important plant viruses. however, to our knowledge, no such list exists. the aim of this review was to survey all plant virologists with an association with molecular plant pathology and ask them to nominate which plant viruses they would place in a 'top 10' based on scientific/economic importance. the survey generated more than 250 votes from the international community, and allowed the gen ... | 2011 | 22017770 |
| molecular interaction between two cassava geminiviruses exhibiting cross-protection. | there are increasing reports of geminivirus mixed infections of field plant hosts. these mixed infections have been suggested to result in recombinations, emergence of new viruses and new disease epidemics. we previously reported the occurrence of mixed infection between african cassava mosaic virus (acmv) and east african cassava mosaic cameroon virus (eacmcv) resulting in severe symptoms in cassava fields in cameroon. here, we show that reassortment of dna-a and dna-b components of acmv and ea ... | 2011 | 21925553 |
| biotechnological approaches to determine the impact of viruses in the energy crop plant jatropha curcas. | abstract: background: geminiviruses infect a wide range of plant species including jatropha and cassava both belonging to family euphorbiaceae. cassava is traditionally an important food crop in sub - saharan countries, while jatropha is considered as valuable biofuel plant with great perspectives in the future. results: a total of 127 jatropha samples from ethiopia and kenya and 124 cassava samples from kenya were tested by enzyme-linked immunosorbent assay (elisa) for rna virus and polymerase ... | 2011 | 21812981 |
| comparison of phenotypes produced in response to transient expression of genes encoded by four distinct begomoviruses in nicotiana benthamiana and their correlation with the levels of developmental mirnas. | abstract: background: whitefly-transmitted geminiviruses (begomoviruses) are a major limiting factor for the production of numerous dicotyledonous crops throughout the world. begomoviruses differ in the number of components that make up their genomes and association with satellites, and yet they cause strikingly similar phenotypes, such as leaf curling, chlorosis and stunted plant growth. micrornas (mirnas) are small endogenous rnas that regulate plant growth and development. the study described ... | 2011 | 21592402 |
| a common set of developmental mirnas are upregulated in nicotiana benthamiana by diverse begomoviruses. | begomoviruses are single-stranded dna viruses that cause economically important diseases of many crops throughout the world and induce symptoms in plants, including enations, leaf curling and stunting, that resemble developmental abnormalities. micrornas (mirnas) are small endogenous rnas that are involved in a variety of activities, including plant development, signal transduction and protein degradation, as well as response to environmental stress, and pathogen invasion. | 2011 | 21447165 |
| differential roles of geminivirus rep and ac4 (c4) in the induction of necrosis in nicotiana benthamiana. | summary the replication-associated protein (rep) of two distinct begomoviruses, the bipartite african cassava mosaic virus (acmv) and the monopartite tomato yellow leaf curl virus-china (tylcv-c), elicits a reaction resembling a hypersensitive response (hr), associated with the induction of local necrosis and a systemic burst of hydrogen peroxide production, when expressed from a potato virus x vector in nicotiana benthamiana. transient expression of the acmv rep after agrobacterium infiltration ... | 2002 | 20569353 |
| differential interaction between cassava mosaic geminiviruses and geminivirus satellites. | geminiviruses are often associated with subviral agents called dna satellites that require proteins encoded by the helper virus for their replication, movement and encapsidation. hitherto, most of the single-stranded dna satellites reported to be associated with members of the family geminiviridae have been associated with monopartite begomoviruses. cassava mosaic disease is known to be caused by viruses belonging to nine different begomovirus species in the african continent and the indian subc ... | 2010 | 20335493 |
| a new strain of indian cassava mosaic virus causes a mosaic disease in the biodiesel crop jatropha curcas. | jatropha curcas mosaic disease is a newly emerging disease that challenges the productivity of a prospective biofuel crop, j. curcas. the aetiology of this disease has not been resolved. here, we report the complete nucleotide sequences of a jatropha virus isolated from dharwad, southern india. phylogenetic analysis of the virus genome suggests it is a new strain of indian cassava mosaic virus. agroinfiltration of the two cloned viral dna components produced systemic infection and typical mosaic ... | 2010 | 20224893 |
| plant geminivirus rep protein induces rereplication in fission yeast. | the replication-associated protein (rep) of geminiviruses, single-stranded dna viruses of higher plants, is essential for virus replication. since these viruses do not encode their own polymerases, rep induces differentiated plant cells to reenter the cell cycle by interacting with the plant homologues of retinoblastoma proteins in order to activate the host dna synthesis machinery. we have used fission yeast (schizosaccharomyces pombe) as a model organism to analyze the impact of ectopically ex ... | 2009 | 19369323 |
| dose-dependent rnai-mediated geminivirus resistance in the tropical root crop cassava. | cassava mosaic disease is a major constraint for cassava production in africa, resulting in significant economic losses. we have engineered transgenic cassava with resistance to african cassava mosaic virus (acmv), by expressing acmv ac1-homologous hairpin double-strand rnas. transgenic cassava lines with high levels of ac1-homologous small rnas have acmv immunity with increasing viral load and different inoculation methods. we report a correlation between the expression of the ac1-homologous sm ... | 2009 | 19300911 |
| validation of high rates of nucleotide substitution in geminiviruses: phylogenetic evidence from east african cassava mosaic viruses. | whitefly-transmitted geminiviruses are major pathogens of the important crop cassava in africa. the intensive sampling and sequencing of cassava mosaic disease-causing viruses that occurred in the wake of a severe outbreak in central africa (1997-2002) allowed us to estimate the rate of evolution of this virus. east african cassava mosaic virus and related species are obligately bipartite (dna-a and dna-b segments), and these two genome segments have different evolutionary histories. despite the ... | 2009 | 19264617 |
| agroinfection of cloned sri lankan cassava mosaic virus dna to arabidopsis thaliana, nicotiana tabacum and cassava. | sri lankan cassava mosaic virus (slcmv) is a bipartite begomovirus infecting cassava in india and sri lanka. we have used agrobacterium-mediated inoculation (agroinoculation) of cloned slcmv dna to inoculate additional hosts, nicotiana tabacum and arabidopsis. although slcmv infection in these hosts caused stunting, leaf deformation and developmental abnormalities, accumulation levels of viral dna in the infected plants suggested that this virus was poorly adapted to them. in the natural host, c ... | 2008 | 18982246 |
| a single amino acid change in a geminiviral rep protein differentiates between triggering a plant defence response and initiating viral dna replication. | we have devised an in planta system for functional analysis of the replication-associated protein (rep) of african cassava mosaic virus (acmv). using this assay and pcr-based random mutagenesis, we have identified an acmv rep mutant that failed to trigger the hypersensitive response (hr), but had an enhanced ability to initiate dna replication. the mutant rep-green fluorescent protein (gfp) fusion protein was localized to the nucleus. sequence analysis showed that the mutated rep gene had three ... | 2008 | 18796734 |
| multiplex pcr for the detection of african cassava mosaic virus and east african cassava mosaic cameroon virus in cassava. | a multiplex pcr was developed for simultaneous detection of african cassava mosaic virus (acmv) and east african cassava mosaic cameroon virus (eacmcv) in cassava affected with cassava mosaic disease (cmd). one set of three primers consisting of an upstream primer common for both viruses and two down stream virus-specific primers were designed for simultaneous amplification of 368 base pair (bp) and 650 bp dna fragments specific to the replicase gene of acmv and eacmcv, respectively. similarly, ... | 2008 | 18789974 |
| alternate hosts of african cassava mosaic virus and east african cassava mosaic cameroon virus in nigeria. | cassava mosaic disease (cmd) caused by african cassava mosaic virus (acmv) and east african cassava mosaic cameroon virus (eacmcv) is the major constraint to cassava production in nigeria. sequences of the dna-a component of acmv and eacmcv isolates from leguminous plant species (senna occidentalis, leucana leucocephala and glycine max), castor oil plant (ricinus communis), a weed host (combretum confertum) and a wild species of cassava (manihot glaziovii) were determined. all acmv isolates from ... | 2008 | 18661095 |
| disassembly of african cassava mosaic virus. | the plant-infecting geminiviruses encapsidate their single-stranded dna genome in characteristic twinned particles that are unique among viruses. these particles are formed by joining two incomplete t=1 icosahedra. african cassava mosaic virions were purified by density-gradient centrifugation from infected nicotiana benthamiana plants and analysed for their stability with respect to ph changes and heat treatment by using electron microscopy. negative staining and rotary shadowing revealed stabl ... | 2008 | 18632975 |
| 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 ... | 2008 | 18559947 |
| phenotypes and functional effects caused by various viral rna silencing suppressors in transgenic nicotiana benthamiana and n. tabacum. | rna silencing suppressor genes derived from six virus genera were transformed into nicotiana benthamiana and n. tabacum plants. these suppressors were p1 of rice yellow mottle virus (rymv), p1 of cocksfoot mottle virus, p19 of tomato bushy stunt virus, p25 of potato virus x, hcpro of potato virus y (strain n), 2b of cucumber mosaic virus (strain kin), and ac2 of african cassava mosaic virus (acmv). hcpro caused the most severe phenotypes in both nicotiana spp. ac2 also produced severe effects in ... | 2008 | 18184062 |
| the role of biotechnology for agricultural sustainability in africa. | sub-saharan africa could have a shortfall of nearly 90mt of cereals by the year 2025 if current agricultural practices are maintained. biotechnology is one of the ways to improve agricultural production. insect-resistant varieties of maize and cotton suitable for the subcontinent have been identified as already having a significant impact. virus-resistant crops are under development. these include maize resistant to the african endemic maize streak virus and cassava resistant to african cassava ... | 2008 | 17761472 |
| transgenic cassava resistance to african cassava mosaic virus is enhanced by viral dna-a bidirectional promoter-derived sirnas. | expression of double-stranded rna (dsrna) homologous to virus sequences can effectively interfere with rna virus infection in plant cells by triggering rna silencing. here we applied this approach against a dna virus, african cassava mosaic virus (acmv), in its natural host cassava. transgenic cassava plants were developed to express small interfering rnas (sirna) from a camv 35s promoter-controlled, intron-containing dsrna cognate to the common region-containing bidirectional promoter of acmv d ... | 2007 | 17492253 |
| infectivity, pseudorecombination and mutagenesis of kenyan cassava mosaic begomoviruses. | cloned dna-a and dna-b components of kenyan isolates of east african cassava mosaic virus (eacmv, eacmv-ug and eacmv-ke2), east african cassava mosaic kenya virus (eacmkv) and east african cassava mosaic zanzibar virus (eacmzv) are shown to be infectious in cassava. eacmv and eacmkv genomic components have the same iteron sequence (ggggg) and can form viable pseudorecombinants, while eacmzv components have a different sequence (ggaga) and are incompatible with eacmv and eacmkv. mutagenesis of ea ... | 2007 | 17412996 |
| resistance to cassava mosaic disease in transgenic cassava expressing antisense rnas targeting virus replication genes. | african cassava mosaic virus (acmv) is a major contributor to cassava mosaic disease (cmd), the economically most important and devastating disease of cassava in africa. we have developed transgenic cassava plants with increased acmv resistance using improved antisense rna technology by targeting the viral mrnas of rep (ac1), trap (ac2) and ren (ac3). viral dna replication assays in detached leaves demonstrated that replication of two acmv isolates was strongly reduced or inhibited in most trans ... | 2005 | 17173627 |
| the oligomeric rep protein of mungbean yellow mosaic india virus (mymiv) is a likely replicative helicase. | geminiviruses replicate by rolling circle mode of replication (rcr) and the viral rep protein initiates rcr by the site-specific nicking at a conserved nonamer (taatatt downward arrow ac) sequence. the mechanism of subsequent steps of the replication process, e.g. helicase activity to drive fork-elongation, etc. has largely remained obscure. here we show that rep of a geminivirus, namely, mungbean yellow mosaic india virus (mymiv), acts as a replicative helicase. the rep-helicase, requiring > or ... | 2006 | 17142233 |
| deletion and recombination events between the dna-a and dna-b components of indian cassava-infecting geminiviruses generate defective molecules in nicotiana benthamiana. | cloned dna-b components, belonging to the bipartite begomoviruses indian cassava mosaic virus (icmv) and sri lankan cassava mosaic virus (slcmv), family geminiviridae, when co-inoculated along with previously cloned dna-a components of the respective viruses onto the experimental host nicotiana benthamiana, generated defective dnas (def-dna) ranging in size from 549 to 1555 nucleotides. all the cloned def-dnas contained the common region (cr) as well as portions of either dna-a or dna-b and, in ... | 2007 | 17109983 |
| tissue and cell tropism of indian cassava mosaic virus (icmv) and its av2 (precoat) gene product. | in order to establish defined viruses for challenging plants in resistance breeding programmes, indian cassava mosaic virus (icmv; family geminiviridae) dna clones were modified to monitor viral spread in plants by replacing the coat protein gene with the green fluorescent protein (gfp) reporter gene. comparative in situ hybridization experiments showed that icmv was restricted to the phloem in cassava and tobacco. gfp-tagged virus spread similarly, resulting in homogeneous fluorescence within n ... | 2007 | 17049959 |
| cassava mosaic virus disease in east and central africa: epidemiology and management of a regional pandemic. | 2006 | 17027685 | |
| genetic diversity and phylogeography of cassava mosaic viruses in kenya. | cassava is a major factor in food security across sub-saharan africa. however, the crop is susceptible to losses due to biotic stresses, in particular to viruses of the genus begomovirus (family geminiviridae) that cause cassava mosaic disease (cmd). during the 1990s, an epidemic of cmd severely hindered cassava production across eastern and central africa. a significant influence on the appearance of virus epidemics is virus diversity. here, a survey of the genetic diversity of cmd-associated b ... | 2006 | 16963765 |
| the use of biolistic inoculation of cassava mosaic begomoviruses in screening cassava for resistance to cassava mosaic disease. | inoculation of cassava with infectious clones of cassava mosaic geminiviruses (geminiviridae: begomovirus) and total dna extracts from plants infected with well-characterised viruses was evaluated using the bio-rad helios gene gun system. total dna extracts from infected plants and cloned viruses were produced for coating gold particles and bombardment onto new cassava genotypes, 96/1089a, 96/1039, 96/0160, 96/0304 and three local landraces tme 117, tme 3 and tme 4. cloned dna of a kenyan isolat ... | 2006 | 16839615 |
| nucleotide sequence of bean golden mosaic virus and a model for gene regulation in geminiviruses. | we have sequenced the genome of bean golden mosaic virus, which comprises two circular single-stranded dna molecules (2646 and 2587 nucleotides long) of mostly unique sequence. comparison of the sequences of bean golden mosaic virus and of cassava latent virus, which share serological relationship but are very different in host range and geographical origin, shows that each virus has a unique 200-nucleotide sequence (common region) on each 2.6-kilobase molecule of its genome. the common regions ... | 1985 | 16593562 |
| expression of a bacterial gene in plants mediated by infectious geminivirus dna. | a viable coat protein deletion mutant of cassava latent virus (clv) dna 1 has been isolated, suggesting that this geminivirus might be exploited as a gene replacement vector. an extensive deletion of 727 nucleotides within the coat protein gene renders dna 1 non-infectious. chimeric clones have been constructed in which the deleted coat protein open reading frame has been replaced by the coding region of the bacterial chloramphenicol acetyl transferase (cat) gene. infectivity is restored to dna ... | 1988 | 16453850 |
| complete nucleotide sequence of the infectious cloned dna components of tomato golden mosaic virus: potential coding regions and regulatory sequences. | the nucleotide sequences of the infectious cloned dna components of tomato golden mosaic virus (tgmv) have been determined. dna a (2588 nucleotides) and dna b (2508 nucleotides) have little sequence homology except for a region of 200 bases which is almost identical in the two molecules. analysis of open reading frames revealed six potential coding regions for proteins of mol. wt. >10 000, four in dna a and two in dna b. possible regulatory signals are identified and a model for bidirectional tr ... | 1984 | 16453557 |
| biodiversity and recombination of cassava-infecting begomoviruses from southern india. | cassava mosaic disease (cmd) is caused by various begomoviruses of the family geminiviridae leading to considerable crop losses in africa and asia. recombination between their genomic components has generated new pathotypes with enhanced virulence in africa. here, we report about a survey on the biodiversity of begomoviruses in cassava from southern india (tamil nadu and kerala states) performed in 2001 and 2002. viral dna a components from stem cuttings were analysed using polymerase chain reac ... | 2006 | 16132175 |
| microrna-binding viral protein interferes with arabidopsis development. | micrornas (mirnas) are small (approximately 21 nt), noncoding rnas that negatively regulate target mrnas at the posttranscriptional level that are involved in development. in plants, virus-induced disease symptoms often result in developmental abnormalities resembling perturbation of mirna-mediated function. here, we report that expression in transgenic plants of a geminivirus-encoded ac4 protein from african cassava mosaic virus cameroon strain (acmv), a suppressor of posttranscriptional gene s ... | 2005 | 16006510 |
| identification of a second begomovirus, sri lankan cassava mosaic virus, causing cassava mosaic disease in india. | the dna a and dna b components of a begomovirus associated with cassava mosaic disease (cmd) originating from kerala, india, were cloned. biolistically inoculated clones induced symptoms typical of cmd in cassava. sequence comparisons showed the virus to be an isolate of sri lankan cassava mosaic virus (slcmv). this is the first time this begomovirus species has been identified in india and only the second species shown to cause cmd in the country. the implication of these findings on our unders ... | 2005 | 15986172 |
| the nucleotide sequence of cloned wheat dwarf virus dna. | restriction analysis and cloning of virus-specific double-stranded dna isolated from plants infected with wheat dwarf virus (wdv) indicated that the virus genome, like that of maize streak virus (msv), consists of a single dna circle. the complete nucleotide sequence of cloned wdv dna (2749 nucleotides) has been determined. comparison of the potential coding regions in wdv dna with those in the dna of two strains of msv suggests that these viruses encode at least two functional proteins, the coa ... | 1985 | 15938050 |
| major polyadenylated transcripts of cassava latent virus and location of the gene encoding coat protein. | the nucleotide sequences of infectious cloned dnas 1 and 2 of a kenyan isolate of cassava latent virus (clv) have been determined. five virus-specific polyadenylated transcripts have been identified and mapped either to the viral or complementary sense dnas of both components of the clv genome, confirming that transcription is bidirectional on both dnas. a major mrna has been translated in vitro to yield a 30 000 mol. wt. product, which is precipitated by antibodies raised against whole virus, a ... | 1985 | 15918226 |
| biolistic infection of cassava using cloned components of indian cassava mosaic virus. | cassava mosaic disease (cmd) is a major constraint to cassava production in africa and asia. of the two begomoviruses associated with cmd on the indian subcontinent, indian cassava mosaic virus (icmv) and sri lankan cassava mosaic virus, only the latter has been successfully reintroduced into cassava to resolve the aetiology of the disease. here, we report the complete nucleotide sequence of an icmv isolate from maharashtra (icmv-[mah2]), central india. biolistic inoculation of the cloned compon ... | 2005 | 15824887 |
| molecular biodiversity of cassava begomoviruses in tanzania: evolution of cassava geminiviruses in africa and evidence for east africa being a center of diversity of cassava geminiviruses. | cassava is infected by numerous geminiviruses in africa and india that cause devastating losses to poor farmers. we here describe the molecular diversity of seven representative cassava mosaic geminiviruses (cmgs) infecting cassava from multiple locations in tanzania. we report for the first time the presence of two isolates in east africa: (eacmcv-[tz1] and eacmcv-[tz7]) of the species east african cassava mosaic cameroon virus, originally described in west africa. the complete nucleotide seque ... | 2005 | 15784145 |
| a geminivirus-induced gene silencing system for gene function validation in cassava. | we have constructed an african cassava mosaic virus (acmv) based gene-silencing vector as a reverse genetics tool for gene function analysis in cassava. the vector carrying a fragment from the nicotiana tabacum sulfur gene (su), encoding one unit of the chloroplast enzyme magnesium chelatase, was used to induce the silencing of the cassava orthologous gene resulting in yellow-white spots characteristic of the inhibition of su expression. this result suggests that well developed sequence database ... | 2004 | 15630624 |
| 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 ... | 2004 | 15630623 |
| both indian cassava mosaic virus and sri lankan cassava mosaic virus are found in india and exhibit high variability as assessed by pcr-rflp. | the biodiversity of geminiviruses associated with the cassava mosaic disease (cmd) in india was investigated using pcr to specifically amplify the dna of indian cassava mosaic virus (icmv) or sri lankan cassava mosaic virus (slcmv) and also by using pcr to amplify specific viral genes, followed by digestion with different restriction endonucleases to obtain polymorphic patterns (pcr-rflp). results showed that both icmv and slcmv were present in mosaic-affected cassava; icmv was geographically re ... | 2005 | 15503225 |
| east african cassava mosaic zanzibar virus - a recombinant begomovirus species with a mild phenotype. | cassava plants exhibiting mild symptoms of cassava mosaic disease (cmd) were collected from unguja island, zanzibar. cuttings grown from these plants in the glasshouse produced similar symptoms, which were milder than those caused by other known cassava mosaic geminiviruses (cmgs). the whitefly vector, bemisia tabaci (gennadius), transmitted the putative virus to 27.7% (n = 18) of target plants. total dna extracted from diseased leaves did not yield diagnostic pcr-bands using virus-specific prim ... | 2004 | 15375675 |
| differential roles of ac2 and ac4 of cassava geminiviruses in mediating synergism and suppression of posttranscriptional gene silencing. | posttranscriptional gene silencing (ptgs) in plants is a natural defense mechanism against virus infection. in mixed infections, virus synergism is proposed to result from suppression of the host defense mechanism by the viruses. synergistic severe mosaic disease caused by simultaneous infection with isolates of the cameroon strain of african cassava mosaic virus (acmv-[cm]) and east african cassava mosaic cameroon virus (eacmcv) in cassava and tobacco is characterized by a dramatic increase in ... | 2004 | 15308741 |
| 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 ... | 2004 | 15220420 |
| geminate structures of african cassava mosaic virus. | two types of geminate structures were purified from african cassava mosaic geminivirus (acmv)-infected nicotiana benthamiana plants and analyzed by electron cryomicroscopy and image reconstruction. after cesium sulfate density gradient centrifugation, they were separated into lighter top (t) and heavier bottom (b) components. t particles comigrated with host proteins, whereas b particles were concentrated in a cesium density typical for complete virions. both particles were composed of two incom ... | 2004 | 15194750 |
| begomoviruses from mungbeans in pakistan: epitope profiles, dna a sequences and phylogenetic relationships. | monoclonal antibodies raised against particles of african cassava mosaic virus, indian cassava mosaic virus or okra leaf curl virus were used to test samples collected in pakistan from begomovirus-infected plants. epitope profiles obtained from cucurbits resembled those previously reported for pakistani begomoviruses. in contrast, epitope profiles obtained from legumes showed little diversity and were quite distinct from these. dna with nucleotide sequences typical of begomovirus dna a component ... | 2004 | 15045567 |
| bemisia tabaci (homoptera: aleyrodidae) biotypes in india. | host plant performance, esterase, and virus transmission tests revealed cassava-strain and sweetpotato-strain populations of whitefly bemisia tabaci (gennadius) biotypes in india. individuals from the sweetpotato-reared population did not breed on cassava, manihot esculenta crantz, and the cassava-strain-reared individuals failed to develop on sweetpotato, ipomoea batatus (l.) lam. eggplant, solanum melongena l., and tobacco, nicotiana tabacum l., were common hosts for both biotypes. the cassava ... | 2003 | 14994796 |
| short deletions in nuclear targeting sequences of african cassava mosaic virus coat protein prevent geminivirus twinned particle formation. | coat proteins (cps) of geminiviruses are multifunctional proteins. using transient expression experiments, we have recently identified putative sequence motifs of african cassava mosaic virus (acmv) cp involved in nuclear import (nls) and export (nes) (virology 286 (2001) 373). here, we report on the effect of corresponding deletion mutants in the context of infecting viruses. since nls and nes may overlap with dna binding and multimerisation domains, we have investigated their effect on viral i ... | 2004 | 14972538 |
| novel system for the simultaneous analysis of geminivirus dna replication and plant interactions in nicotiana benthamiana. | the origin of replication of african cassava mosaic virus (acmv) and a gene expression vector based on potato virus x were exploited to devise an in planta system for functional analysis of the geminivirus replication-associated protein (rep) in transgenic nicotiana benthamiana line pori-2. this line contains an integrated copy of a tandem repeat of the acmv origin of replication flanking nonviral sequences that can be mobilized and replicated by rep as an episomal replicon. a rep-gfp fusion pro ... | 2003 | 14645587 |
| short interfering rna-mediated interference of gene expression and viral dna accumulation in cultured plant cells. | gene silencing mediated by double-stranded rna is a sequence-specific rna degradation mechanism highly conserved in eukaryotes that serves as an antiviral defense pathway in both plants and drosophila. short interfering rnas (sirnas), the 21- to 23-nt double-stranded intermediates of this natural defense mechanism, are becoming powerful tools for reducing gene expression and countering viral infection in a variety of mammalian cells. here we report the use of sirnas to target reporter gene expre ... | 2003 | 12886005 |
| efficient replication of cloned african cassava mosaic virus in cassava leaf disks. | a transient viral replication assay for cloned african cassava mosaic virus (acmv) was developed using cassava leaf disks. tms60444 leaf disks were transfected using biolistic-mediated inoculation with acmv clones pkacmva and pkacmvb, which originate from west kenya acmv isolate 844 (acmv-ke). viral dna synthesized de novo was monitored by southern hybridization with an av1 dna probe. by using the methylation-sensitive restriction enzymes dpni and mboi, it was possible to distinguish between the ... | 2003 | 12606075 |
| co-adaptation between cassava mosaic geminiviruses and their local vector populations. | four cassava mosaic geminivirus (cmg) isolates; african cassava mosaic virus from namulonge, uganda (acmv-[nam]), east african cassava mosaic virus from mtwara, tanzania (eacmv-[mtw]), eacmv-uganda from namulonge (eacmv-ug[nam]) and indian cassava mosaic virus from trivandrum, india (icmv-[tri]) were compared for their ability to be transmitted by four colonies of cassava whitefly, bemisia tabaci (gennadius), collected from namulonge (nam), mtwara (mtw), kumasi (kum) and trivandrum (tri). with 2 ... | 2002 | 12076831 |
| a distinct bemisia tabaci (gennadius) (hemiptera: sternorrhyncha: aleyrodidae) genotype cluster is associated with the epidemic of severe cassava mosaic virus disease in uganda. | during the 1990s, an epidemic of cassava mosaic virus disease caused major losses to cassava production in uganda. two factors associated with the epidemic were the occurrence of a novel recombinant begomovirus, eacmv-ug, and unusually high populations of the whitefly vector, bemisia tabaci. here we present molecular evidence for the occurrence of two cassava-colonizing b. tabaci genotype clusters, ug1 and ug2, one of which, ug2, can be consistently associated with the cmd epidemic in uganda at ... | 2002 | 12074729 |
| mutation of three cysteine residues in tomato yellow leaf curl virus-china c2 protein causes dysfunction in pathogenesis and posttranscriptional gene-silencing suppression. | the nuclear localized c2 protein of the monopartite begomovirus tomato yellow leaf curl virus-china (tylcv-c) contributes to viral pathogenicity. here, we have investigated tylcv-c c2 protein domains that play a role in the phenotype. alignment of the c2 protein with 67 homologues from monopartite and bipartite begomoviruses revealed that a putative zinc-finger motif c36-x1-c38-x7-c46-x6-h53-x4-h58c59 and four potential phosphorylation sites (t52, s61, y68, and s74) are highly conserved. when ex ... | 2002 | 11952122 |
| characterisation of sri lankan cassava mosaic virus and indian cassava mosaic virus: evidence for acquisition of a dna b component by a monopartite begomovirus. | two bipartite begomoviruses, indian cassava mosaic virus (icmv) and sri lankan cassava mosaic virus (slcmv), have been isolated from mosaic-diseased cassava originating from central india and sri lanka, respectively. icmv was transmitted with low efficiency from cassava to nicotiana benthamiana by sap inoculation to give leaf curl symptoms. slcmv was much more virulent in this host, producing severe stunting, leaf curl, and chlorosis. these symptoms were reproduced when their cloned genomic comp ... | 2002 | 11853400 |
| molecular evidence for diverse populations of cassava-infecting begomoviruses in southern africa. | in this paper we describe results obtained from screening field populations of begomoviruses from infected cassava from six countries in southern africa. it was found that african cassava mosaic virus occurs in five of the six countries (except angola), east african cassava mosaic virus is present in five countries (except zambia) and south african cassava mosaic virus was detected only in south africa and swaziland. in addition, we report for the first time in southern africa, the appearance of ... | 2001 | 11699964 |
| subcellular targeting of the coat protein of african cassava mosaic geminivirus. | the coat protein (cp) of geminiviruses is involved in a number of processes during the life cycle of the virus. the predominant function is encapsidation of single-stranded dna and formation of the virus particle to protect viral dna during transmission. the cp of monopartite geminiviruses is absolutely essential for virus movement, whereas cp mutants of bipartite geminiviruses are able to infect some host plants systemically, indicating an involvement of the cp in host specificity. during the l ... | 2001 | 11485405 |
| expression of the oligomerization domain of the replication-associated protein (rep) of tomato leaf curl new delhi virus interferes with dna accumulation of heterologous geminiviruses. | the minimal dna binding domain of the replication-associated protein (rep) of tomato leaf curl new delhi virus was determined by electrophoretic mobility gel shift analysis and co-purification assays. dna binding activity maps to amino acids 1-160 (rep-(1-160)) of the rep protein and overlaps with the protein oligomerization domain. transient expression of rep protein (rep-(1-160)) was found to inhibit homologous viral dna accumulation by 70-86% in tobacco protoplasts and in nicotiana benthamian ... | 2001 | 11342533 |
| simultaneous analysis of the bidirectional african cassava mosaic virus promoter activity using two different luciferase genes. | the expression of geminivirus genes is controlled by bidirectional promoters which are located in the large intergenic region of the circular dna genomes and specifically regulated by virus encoded proteins. in order to study the simultaneous regulation of both orientations of the dna a and dna b promoters of african cassava mosaic virus (acmv), they were cloned between two different luciferase genes with the firefly luciferase gene in complementary-sense and the renilla luciferase gene in virio ... | 2001 | 11324760 |