| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |