The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
Erwin Aballay - One of the best experts on this subject based on the ideXlab platform.
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exoenzymes and metabolites related to the nematicidal effect of rhizobacteria on Xiphinema Index thorne allen
Journal of Applied Microbiology, 2016Co-Authors: C Castanedaalvarez, S Prodan, I M Rosales, Erwin AballayAbstract:AIMS: To identify enzymes and metabolites in the rhizobacteria filtrates that have a nematicidal effect on Xiphinema Index and perform molecular characterization of the strains evaluated. METHODS AND RESULTS: A series of four bacteria selected for their nematicidal potential were considered for in vitro, biochemical and molecular studies. The direct effect of the bacterial filtrates was evaluated in vitro on X. Index juveniles and adults. Hydrogen sulphide and hydrogen cyanide liberation and protease, chitinase, collagenase and lipase activity were verified in the strains. Up to five housekeeping genes and one ITS 16S-23S rRNA were analysed. All bacterial filtrates presented 54-100% mortality when evaluated during up to 72 h of nematode exposure. Strains presented protease activity; two of them (strains FB833T and FR203A) showed reliable collagenase and chitinase activities, respectively, and three of them showed strong lipolytic activity (FB833T, FR203A and FS213P). Strain Bacillus megaterium FB133M had no lipase activity and presented the lowest nematicidal effect. Bacillus amyloliquefaciens FR203A had the largest lethal effect. CONCLUSION: The rhizobacteria strains evaluated in this study possess nematicidal compounds, which may offer an interesting alternative for X. Index control. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of exoenzymes and metabolites associated with nematicidal effect of rhizobacteria on X. Index, which can be a possible alternative for control of this plant-parasitic nematode.
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Exoenzymes and metabolites related to the nematicidal effect of rhizobacteria on Xiphinema Index Thorne & Allen.
Journal of Applied Microbiology, 2016Co-Authors: C. Castaneda‐alvarez, I M Rosales, S Prodan, Erwin AballayAbstract:AIMS: To identify enzymes and metabolites in the rhizobacteria filtrates that have a nematicidal effect on Xiphinema Index and perform molecular characterization of the strains evaluated. METHODS AND RESULTS: A series of four bacteria selected for their nematicidal potential were considered for in vitro, biochemical and molecular studies. The direct effect of the bacterial filtrates was evaluated in vitro on X. Index juveniles and adults. Hydrogen sulphide and hydrogen cyanide liberation and protease, chitinase, collagenase and lipase activity were verified in the strains. Up to five housekeeping genes and one ITS 16S-23S rRNA were analysed. All bacterial filtrates presented 54-100% mortality when evaluated during up to 72 h of nematode exposure. Strains presented protease activity; two of them (strains FB833T and FR203A) showed reliable collagenase and chitinase activities, respectively, and three of them showed strong lipolytic activity (FB833T, FR203A and FS213P). Strain Bacillus megaterium FB133M had no lipase activity and presented the lowest nematicidal effect. Bacillus amyloliquefaciens FR203A had the largest lethal effect. CONCLUSION: The rhizobacteria strains evaluated in this study possess nematicidal compounds, which may offer an interesting alternative for X. Index control. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report of exoenzymes and metabolites associated with nematicidal effect of rhizobacteria on X. Index, which can be a possible alternative for control of this plant-parasitic nematode.
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assessment of rhizobacteria from grapevine for their suppressive effect on the parasitic nematode Xiphinema Index
Crop Protection, 2012Co-Authors: Erwin Aballay, S Prodan, Anna Martensson, Paula PerssonAbstract:The capacity of rhizobacteria isolated from grape plants to protect grapevine roots from damage by the nematode Xiphinema Index was assessed in trials carried out in the growing season 2008e2009 and 2009e2010. A total of two groups of bacteria were evaluated, one comprising 49 isolates, of which 37 were assessed in previous studies, and one comprising 90 isolates not previously evaluated. Two assays were performed on the first group, one per season, and one on the second group, lasting two growing seasons. Pots of field soil (3 L) planted with two-month old Thompson Seedless vines were inoculated with 200 or 400 specimens of X. Index after inoculation with 10 6 cfu/ml of test rhizobacteria; the posts were maintained in a shaded greenhouse. Seven isolates from the first group of bacteria (Bacillus brevis, Bacillus megaterium, Cytophaga johnsonae, Pseudomonas fluorescens, Rahnella aquatilis and Stenotrophomonas maltophilia) were effective in decreasing damage in both of the assays (P < 0.05). Ten isolates from the second group (Variovorax paradoxus, Pseudomonas pseudoalcaligenes, Bacillus mycoides, Bacillus sphaericus, Bacillus thuringiensis, Curtobacterium flaccumfaciens, Pseudomonas putida, Pseudomonas alcaligenes and Pseudomonas viridiflava) resulted in the lowest number of galls per gram root. B. brevis and B. megaterium also demonstrated good activity in previous studies on grape plants and are thus promising candidates for further research.
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screening of rhizosphere bacteria from grapevine for their suppressive effect on Xiphinema Index thorne allen on in vitro grape plants
Plant and Soil, 2011Co-Authors: Erwin Aballay, Anna Martensson, Paula PerssonAbstract:Xiphinema Index is the most aggressive root parasite affecting vines in Chile, controlled mainly chemically. The aim of this study was to identify rhizobacteria in grapevine roots growing in infested soils and to determine if some of these affect the parasitism caused by the nematode. Rhizobacteria of ungrafted grapevine cultivars from 11 vineyards were isolated using TSBA and identified with FAMEs analysis. The antagonistic effect to X. Index of those from soils 1 to 4 was assessed in 500 ml pots treating 2 months old in vitro plants with a bacterial suspension containing 1 × 106 c.f.u./ml and 400 nematodes, determining after 4 months growth nematode populations and root damages. Also culture filtrates were assessed. 400 isolates in 25 genera were obtained from the 11 vineyards. The most frequent species were Pseudomonas putida (35.1%), Escherichia coli (7.6%) and Pseudomonas fluorescens (6.1%). Isolates of soils 1 to 4, show that Bacillus megaterium, B. brevis, Pseudomonas corrugata, P. savastanoi, Stenotrophomonas maltophilia and Serratia plymuthica reduced root damage and suppressed populations, meanwhile strains of B. brevis and Comamonas acidovorans increased plant growth but did not control nematodes. It is concluded that these isolates may be useful in biological control programmes in vineyards.
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Screening of rhizosphere bacteria from grapevine for their suppressive effect on Xiphinema Index Thorne & Allen on in vitro grape plants
Plant and Soil, 2011Co-Authors: Erwin Aballay, Anna Martensson, Paula PerssonAbstract:Xiphinema Index is the most aggressive root parasite affecting vines in Chile, controlled mainly chemically. The aim of this study was to identify rhizobacteria in grapevine roots growing in infested soils and to determine if some of these affect the parasitism caused by the nematode. Rhizobacteria of ungrafted grapevine cultivars from 11 vineyards were isolated using TSBA and identified with FAMEs analysis. The antagonistic effect to X. Index of those from soils 1 to 4 was assessed in 500 ml pots treating 2 months old in vitro plants with a bacterial suspension containing 1 × 106 c.f.u./ml and 400 nematodes, determining after 4 months growth nematode populations and root damages. Also culture filtrates were assessed. 400 isolates in 25 genera were obtained from the 11 vineyards. The most frequent species were Pseudomonas putida (35.1%), Escherichia coli (7.6%) and Pseudomonas fluorescens (6.1%). Isolates of soils 1 to 4, show that Bacillus megaterium, B. brevis, Pseudomonas corrugata, P. savastanoi, Stenotrophomonas maltophilia and Serratia plymuthica reduced root damage and suppressed populations, meanwhile strains of B. brevis and Comamonas acidovorans increased plant growth but did not control nematodes. It is concluded that these isolates may be useful in biological control programmes in vineyards.
Gerard Demangeat - One of the best experts on this subject based on the ideXlab platform.
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detection of multiple variants of grapevine fanleaf virus in single Xiphinema Index nematodes
Viruses, 2019Co-Authors: Shahinez Garcia, Gerard Demangeat, Veronique Komar, Olivier Lemaire, Jeanmichel Hily, Claude Gertz, Emmanuelle VigneAbstract:Grapevine fanleaf virus (GFLV) is responsible for a widespread disease in vineyards worldwide. Its genome is composed of two single-stranded positive-sense RNAs, which both show a high genetic diversity. The virus is transmitted from grapevine to grapevine by the ectoparasitic nematode Xiphinema Index. Grapevines in diseased vineyards are often infected by multiple genetic variants of GFLV but no information is available on the molecular composition of virus variants retained in X. Index following nematodes feeding on roots. In this work, aviruliferous X. Index were fed on three naturally GFLV-infected grapevines for which the virome was characterized by RNAseq. Six RNA-1 and four RNA-2 molecules were assembled segregating into four and three distinct phylogenetic clades of RNA-1 and RNA-2, respectively. After 19 months of rearing, single and pools of 30 X. Index tested positive for GFLV. Additionally, either pooled or single X. Index carried multiple variants of the two GFLV genomic RNAs. However, the full viral genetic diversity found in the leaves of infected grapevines was not detected in viruliferous nematodes, indicating a genetic bottleneck. Our results provide new insights into the complexity of GFLV populations and the putative role of X. Index as reservoirs of virus diversity.
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in vitro acquisition of specific small interfering rnas inhibits the expression of some target genes in the plant ectoparasite Xiphinema Index
International Journal of Molecular Sciences, 2019Co-Authors: Aurelie Marmonier, Gerard Demangeat, Laetitia Perfusbarbeoch, Corinne Rancurel, Sylvaine Boissinot, Bruno Favery, Veronique BraultAbstract:Xiphinema Index is an important plant parasitic nematode that induces direct damages and specifically transmits the Grapevine fanleaf virus, which is particularly harmful for grapevines. Genomic resources of this nematode species are still limited and no functional gene validation technology is available. RNA interference (RNAi) is a powerful technology to study gene function and here we describe the application of RNAi on several genes in X. Index. Soaking the nematodes for 48 h in a suspension containing specific small interfering RNAs resulted in a partial inhibition of the accumulation of some targeted mRNA. However, low reproducible silencing efficiency was observed which could arise from X. Index silencing pathway deficiencies. Indeed, essential accustomed proteins for these pathways were not found in the X. Index proteome predicted from transcriptomic data. The most reproducible silencing effect was obtained when targeting the piccolo gene potentially involved in endo-exocytosis of synaptic molecules. This represents the first report of gene silencing in a nematode belonging to the Longidoridae family.
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control of Xiphinema Index populations by fallow plants under greenhouse and field conditions
Phytopathology, 2012Co-Authors: L Villate, Gerard Demangeat, Elisa Morin, Maarten Van Helden, D EsmenjaudAbstract:ABSTRACT The dagger nematode Xiphinema Index has a high economic impact in vineyards by direct pathogenicity and above all by transmitting the Grapevine fanleaf virus (GFLV). Agrochemicals have been largely employed to restrict the spread of GFLV by reducing X. Index populations but are now banned. As an alternative to nematicides, the use of fallow plants between two successive vine crops was assessed. We selected plant species adapted to vineyard soils and exhibiting negative impact on nematodes and we evaluated their antagonistic effect on X. Index in greenhouse using artificially infested soil, and in naturally infested vineyard conditions. The screening was conducted with plants belonging to the families Asteraceae (sunflower, marigold, zinnia, and nyjer), Poaceae (sorghum and rye), Fabaceae (white lupin, white melilot, hairy vetch, and alfalfa), Brassicaceae (rapeseed and camelina), and Boraginaceae (phacelia). In the greenhouse controlled assay, white lupin, nyjer, and marigold significantly reduce...
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transmission competency of single female Xiphinema Index lines for grapevine fanleaf virus
Phytopathology, 2010Co-Authors: Gerard Demangeat, Veronique Komar, Cyril Vanghelder, R Voisin, Olivier Lemaire, D Esmenjaud, Marc FuchsAbstract:ABSTRACT Grapevine fanleaf virus (GFLV) is vectored specifically from grapevine to grapevine by the ectoparasitic nematode Xiphinema Index. Limited information is available on the vector competency of X. Index populations from diverse geographical origins. We determined the transmissibility of two GFLV strains showing 4.6% amino acid divergence within their coat protein (e.g., strains F13 and GHu) by seven clonal lines of X. Index developed from seven distinct populations from the Mediterranean basin (Cyprus, southern France, Israel, Italy, and Spain), northern France, and California. X. Index lines derived from single adult females were produced on fig (Ficus carica) plants to obtain genetically homogenous aviruliferous clones. A comparative reproductive rate analysis on Vitis rupestris du Lot and V. vinifera cv. Cabernet Sauvignon showed significant differences among clones, with the single-female Cyprus line showing the highest rate (30-fold the initial population) and the Spain and California lines sh...
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survival of Xiphinema Index in vineyard soil and retention of grapevine fanleaf virus over extended time in the absence of host plants
Phytopathology, 2005Co-Authors: Gerard Demangeat, R Voisin, Marc Fuchs, Jc Minot, N Bosselut, D EsmenjaudAbstract:ABSTRACT Grapevine fanleaf virus (GFLV) is transmitted specifically from grapevine to grapevine by the ectoparasitic root-feeding nematode Xiphinema Index. Limited information is available on the survival of X. Index in vineyard soil and on the retention of GFLV by X. Index over extended periods of time. We addressed these two issues by quantifying the numbers of living X. Index recovered from soil samples that were collected in three naturally GFLV-infected vineyards in France and subsequently stored at 7 or 20°C in the absence of host plants. Our data indicated a two- to eightfold decrease in X. Index numbers but the recovery of 8 to 10 living fourth-stage juveniles (J4) and adults per kilogram of soil after 4 years of storage regardless of temperature. In addition, GFLV was detected readily in all groups of 20 isolated X. Index adults and J4 (except for J4 that were kept 4 years at 20°C) by reverse transcription-polymerase chain reaction using total nematode RNAs and a primer set located in conserved r...
D Esmenjaud - One of the best experts on this subject based on the ideXlab platform.
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control of Xiphinema Index populations by fallow plants under greenhouse and field conditions
Phytopathology, 2012Co-Authors: L Villate, Gerard Demangeat, Elisa Morin, Maarten Van Helden, D EsmenjaudAbstract:ABSTRACT The dagger nematode Xiphinema Index has a high economic impact in vineyards by direct pathogenicity and above all by transmitting the Grapevine fanleaf virus (GFLV). Agrochemicals have been largely employed to restrict the spread of GFLV by reducing X. Index populations but are now banned. As an alternative to nematicides, the use of fallow plants between two successive vine crops was assessed. We selected plant species adapted to vineyard soils and exhibiting negative impact on nematodes and we evaluated their antagonistic effect on X. Index in greenhouse using artificially infested soil, and in naturally infested vineyard conditions. The screening was conducted with plants belonging to the families Asteraceae (sunflower, marigold, zinnia, and nyjer), Poaceae (sorghum and rye), Fabaceae (white lupin, white melilot, hairy vetch, and alfalfa), Brassicaceae (rapeseed and camelina), and Boraginaceae (phacelia). In the greenhouse controlled assay, white lupin, nyjer, and marigold significantly reduce...
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transmission competency of single female Xiphinema Index lines for grapevine fanleaf virus
Phytopathology, 2010Co-Authors: Gerard Demangeat, Veronique Komar, Cyril Vanghelder, R Voisin, Olivier Lemaire, D Esmenjaud, Marc FuchsAbstract:ABSTRACT Grapevine fanleaf virus (GFLV) is vectored specifically from grapevine to grapevine by the ectoparasitic nematode Xiphinema Index. Limited information is available on the vector competency of X. Index populations from diverse geographical origins. We determined the transmissibility of two GFLV strains showing 4.6% amino acid divergence within their coat protein (e.g., strains F13 and GHu) by seven clonal lines of X. Index developed from seven distinct populations from the Mediterranean basin (Cyprus, southern France, Israel, Italy, and Spain), northern France, and California. X. Index lines derived from single adult females were produced on fig (Ficus carica) plants to obtain genetically homogenous aviruliferous clones. A comparative reproductive rate analysis on Vitis rupestris du Lot and V. vinifera cv. Cabernet Sauvignon showed significant differences among clones, with the single-female Cyprus line showing the highest rate (30-fold the initial population) and the Spain and California lines sh...
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host suitability of vitis and vitis muscadinia material to the nematode Xiphinema Index over one to four years
American Journal of Enology and Viticulture, 2010Co-Authors: D Esmenjaud, R Voisin, Cyril Van Ghelder, Louis Bordenave, Stephane Decroocq, A Bouquet, Nathalie OllatAbstract:The dagger nematode Xiphinema Index specifically transmits Grapevine fanleaf virus (GFLV), which causes progressive grape degeneration in vineyards worldwide. Nematode-resistant rootstocks are a promising alternative to the ban of nematicides. We report the evaluation, under controlled conditions in two independent experiments, of the host suitability (reproduction factor, RF) of 40 Vitis and Vitis - Muscadinia accessions to the isofemale line Frejus of X. Index. In the first experiment, 17 accessions, grown from either in vitro culture or cuttings, were evaluated after 1 and 3 years and, for four accessions, also after 4 years. The nematode multiplied early and late on reference rootstocks V. rupestris du Lot and V. riparia Gloire de Montpellier, respectively. Among Vitis - Muscadinia material, after 1 and 3 years, accession VRH 8624 had high RFs, while VRH 8771 and NC 35–50 had RFs close to 1. The nematode-resistant candidate rootstock accession RPG1 (=VRH 8771 x Vitis rootstock 140Ru) and the intergeneric hybrid VRH 97-99-79 had RFs significantly higher at 4 years than at 1 year, suggesting a progressive adaptation of the nematode to the plant resistance factors. Most Vitis botanic accessions had high RFs at both 1-year and 3-year durations. Low RFs, observed for the remaining accessions, were probably due to the poor root development and the subsequent difficult access of nematodes to feeding on this material. In the second experiment, 23 Vitis accessions, evaluated only at 3 years, had high RFs, except for a few accessions that expressed low RFs and poor development. Thus some muscadine-derived intergeneric hybrids are promising resistance sources that must be confirmed using nematode lines from other geographic origins.
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permanent genetic resources note development of nine polymorphic microsatellite markers for the phytoparasitic nematode Xiphinema Index the vector of the grapevine fanleaf virus
2009Co-Authors: L Villate, S Coedel, D Esmenjaud, Olivier PlantardAbstract:We report isolation, characterization and cross-species amplification of nine microsatellite loci from the phytoparasitic nematode Xiphinema Index, the vector of grapevine fanleaf virus. Levels of polymorphism were evaluated in 62 individuals from two X. Index populations. The number of alleles varies between two and 10 depending on locus and population. Observed heterozygosity on loci across both populations varied from 0.32 to 0.857 (mean 0.545). The primers were tested for cross-species amplification in three other species of phytoparasitic nematodes of the Xiphinema genus. These nine microsatellite loci constitute valuable markers for population genetics and phylogeographical studies of X. Index.
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survival of Xiphinema Index in vineyard soil and retention of grapevine fanleaf virus over extended time in the absence of host plants
Phytopathology, 2005Co-Authors: Gerard Demangeat, R Voisin, Marc Fuchs, Jc Minot, N Bosselut, D EsmenjaudAbstract:ABSTRACT Grapevine fanleaf virus (GFLV) is transmitted specifically from grapevine to grapevine by the ectoparasitic root-feeding nematode Xiphinema Index. Limited information is available on the survival of X. Index in vineyard soil and on the retention of GFLV by X. Index over extended periods of time. We addressed these two issues by quantifying the numbers of living X. Index recovered from soil samples that were collected in three naturally GFLV-infected vineyards in France and subsequently stored at 7 or 20°C in the absence of host plants. Our data indicated a two- to eightfold decrease in X. Index numbers but the recovery of 8 to 10 living fourth-stage juveniles (J4) and adults per kilogram of soil after 4 years of storage regardless of temperature. In addition, GFLV was detected readily in all groups of 20 isolated X. Index adults and J4 (except for J4 that were kept 4 years at 20°C) by reverse transcription-polymerase chain reaction using total nematode RNAs and a primer set located in conserved r...
Marc Fuchs - One of the best experts on this subject based on the ideXlab platform.
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transmission competency of single female Xiphinema Index lines for grapevine fanleaf virus
Phytopathology, 2010Co-Authors: Gerard Demangeat, Veronique Komar, Cyril Vanghelder, R Voisin, Olivier Lemaire, D Esmenjaud, Marc FuchsAbstract:ABSTRACT Grapevine fanleaf virus (GFLV) is vectored specifically from grapevine to grapevine by the ectoparasitic nematode Xiphinema Index. Limited information is available on the vector competency of X. Index populations from diverse geographical origins. We determined the transmissibility of two GFLV strains showing 4.6% amino acid divergence within their coat protein (e.g., strains F13 and GHu) by seven clonal lines of X. Index developed from seven distinct populations from the Mediterranean basin (Cyprus, southern France, Israel, Italy, and Spain), northern France, and California. X. Index lines derived from single adult females were produced on fig (Ficus carica) plants to obtain genetically homogenous aviruliferous clones. A comparative reproductive rate analysis on Vitis rupestris du Lot and V. vinifera cv. Cabernet Sauvignon showed significant differences among clones, with the single-female Cyprus line showing the highest rate (30-fold the initial population) and the Spain and California lines sh...
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survival of Xiphinema Index in vineyard soil and retention of grapevine fanleaf virus over extended time in the absence of host plants
Phytopathology, 2005Co-Authors: Gerard Demangeat, R Voisin, Marc Fuchs, Jc Minot, N Bosselut, D EsmenjaudAbstract:ABSTRACT Grapevine fanleaf virus (GFLV) is transmitted specifically from grapevine to grapevine by the ectoparasitic root-feeding nematode Xiphinema Index. Limited information is available on the survival of X. Index in vineyard soil and on the retention of GFLV by X. Index over extended periods of time. We addressed these two issues by quantifying the numbers of living X. Index recovered from soil samples that were collected in three naturally GFLV-infected vineyards in France and subsequently stored at 7 or 20°C in the absence of host plants. Our data indicated a two- to eightfold decrease in X. Index numbers but the recovery of 8 to 10 living fourth-stage juveniles (J4) and adults per kilogram of soil after 4 years of storage regardless of temperature. In addition, GFLV was detected readily in all groups of 20 isolated X. Index adults and J4 (except for J4 that were kept 4 years at 20°C) by reverse transcription-polymerase chain reaction using total nematode RNAs and a primer set located in conserved r...
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sensitive and reliable detection of grapevine fanleaf virus in a single Xiphinema Index nematode vector
Journal of Virological Methods, 2004Co-Authors: Gerard Demangeat, Veronique Komar, D Esmenjaud, Pascal Cornuet, Marc FuchsAbstract:Grapevine fanleaf virus (GFLV) is specifically transmitted from plant to plant by the ectoparasitic nematode Xiphinema Index. A sensitive and reliable procedure was developed to readily detect GFLV in a single viruliferous X. Index, regardless of the nematode origin, i.e. greenhouse rearings or vineyard soils. The assay is based on bead milling to disrupt nematodes extracted from soil samples, solid-phase extraction of total nematode RNAs, and amplification of a 555 bp fragment of the coat protein (CP) gene by reverse transcription-polymerase chain reaction with two primers designed from conserved sequences. This procedure is sensitive since the CP gene fragment is amplified from an artificial sample consisting of one viruliferous nematode mixed with 3000 aviruliferous individuals. In addition, StyI RFLP analysis of the CP amplicon enables the GFLV isolate carried by a single viruliferous X. Index to be characterized. This GFLV detection assay opens new avenues for epidemiological studies and for molecular investigations on the mechanism of X. Index-mediated GFLV transmission.
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the specific transmission of grapevine fanleaf virus by its nematode vector Xiphinema Index is solely determined by the viral coat protein
Virology, 2004Co-Authors: P Andretlink, Gerard Demangeat, Veronique Komar, Corinne Schmittkeichinger, Marc FuchsAbstract:Abstract The viral determinants involved in the specific transmission of Grapevine fanleaf virus (GFLV) by its nematode vector Xiphinema Index are located within the 513 C-terminal residues of the RNA2-encoded polyprotein, that is, the 9 C-terminal amino acids of the movement protein (2BMP) and contiguous 504 amino acids of the coat protein (2CCP) [Virology 291 (2001) 161]. To further delineate the viral determinants responsible for the specific spread, the four amino acids that are different within the 9 C-terminal 2BMP residues between GFLV and Arabis mosaic virus (ArMV), another nepovirus which is transmitted by Xiphinema diversicaudatum but not by X. Index, were subjected to mutational analysis. Of the recombinant viruses derived from transcripts of GFLV RNA1 and RNA2 mutants that systemically infected herbaceous host plants, all with the 2CCP of GFLV were transmitted by X. Index unlike none with the 2CCP of ArMV, regardless of the mutations within the 2BMP C-terminus. These results demonstrate that the coat protein is the sole viral determinant for the specific spread of GFLV by X. Index.
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involvement of rna2 encoded proteins in the specific transmission of grapevine fanleaf virus by its nematode vector Xiphinema Index
Virology, 2001Co-Authors: Christophe Belin, Gerard Demangeat, Veronique Komar, L Pinck, Corinne Schmitt, Marc FuchsAbstract:Abstract The nepovirus Grapevine fanleaf virus (GFLV) is specifically transmitted by the nematode Xiphinema Index. To identify the RNA2-encoded proteins involved in X. Index -mediated spread of GFLV, chimeric RNA2 constructs were engineered by replacing the 2A, 2B MP , and/or 2C CP sequences of GFLV with their counterparts in Arabis mosaic virus (ArMV), a closely related nepovirus which is transmitted by Xiphinema diversicaudatum but not by X. Index. Among the recombinant viruses obtained from transcripts of GFLV RNA1 and chimeric RNA2, only those which contained the 2C CP gene (504 aa) and 2B MP contiguous 9 C-terminal residues of GFLV were transmitted by X. Index as efficiently as natural and synthetic wild-type GFLV, regardless of the origin of the 2A and 2B MP genes. As expected, ArMV was not transmitted probably because it is not retained by X. Index. These results indicate that the determinants responsible for the specific spread of GFLV by X. Index are located within the 513 C-terminal residues of the polyprotein encoded by RNA2.
Paula Persson - One of the best experts on this subject based on the ideXlab platform.
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assessment of rhizobacteria from grapevine for their suppressive effect on the parasitic nematode Xiphinema Index
Crop Protection, 2012Co-Authors: Erwin Aballay, S Prodan, Anna Martensson, Paula PerssonAbstract:The capacity of rhizobacteria isolated from grape plants to protect grapevine roots from damage by the nematode Xiphinema Index was assessed in trials carried out in the growing season 2008e2009 and 2009e2010. A total of two groups of bacteria were evaluated, one comprising 49 isolates, of which 37 were assessed in previous studies, and one comprising 90 isolates not previously evaluated. Two assays were performed on the first group, one per season, and one on the second group, lasting two growing seasons. Pots of field soil (3 L) planted with two-month old Thompson Seedless vines were inoculated with 200 or 400 specimens of X. Index after inoculation with 10 6 cfu/ml of test rhizobacteria; the posts were maintained in a shaded greenhouse. Seven isolates from the first group of bacteria (Bacillus brevis, Bacillus megaterium, Cytophaga johnsonae, Pseudomonas fluorescens, Rahnella aquatilis and Stenotrophomonas maltophilia) were effective in decreasing damage in both of the assays (P < 0.05). Ten isolates from the second group (Variovorax paradoxus, Pseudomonas pseudoalcaligenes, Bacillus mycoides, Bacillus sphaericus, Bacillus thuringiensis, Curtobacterium flaccumfaciens, Pseudomonas putida, Pseudomonas alcaligenes and Pseudomonas viridiflava) resulted in the lowest number of galls per gram root. B. brevis and B. megaterium also demonstrated good activity in previous studies on grape plants and are thus promising candidates for further research.
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screening of rhizosphere bacteria from grapevine for their suppressive effect on Xiphinema Index thorne allen on in vitro grape plants
Plant and Soil, 2011Co-Authors: Erwin Aballay, Anna Martensson, Paula PerssonAbstract:Xiphinema Index is the most aggressive root parasite affecting vines in Chile, controlled mainly chemically. The aim of this study was to identify rhizobacteria in grapevine roots growing in infested soils and to determine if some of these affect the parasitism caused by the nematode. Rhizobacteria of ungrafted grapevine cultivars from 11 vineyards were isolated using TSBA and identified with FAMEs analysis. The antagonistic effect to X. Index of those from soils 1 to 4 was assessed in 500 ml pots treating 2 months old in vitro plants with a bacterial suspension containing 1 × 106 c.f.u./ml and 400 nematodes, determining after 4 months growth nematode populations and root damages. Also culture filtrates were assessed. 400 isolates in 25 genera were obtained from the 11 vineyards. The most frequent species were Pseudomonas putida (35.1%), Escherichia coli (7.6%) and Pseudomonas fluorescens (6.1%). Isolates of soils 1 to 4, show that Bacillus megaterium, B. brevis, Pseudomonas corrugata, P. savastanoi, Stenotrophomonas maltophilia and Serratia plymuthica reduced root damage and suppressed populations, meanwhile strains of B. brevis and Comamonas acidovorans increased plant growth but did not control nematodes. It is concluded that these isolates may be useful in biological control programmes in vineyards.
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Screening of rhizosphere bacteria from grapevine for their suppressive effect on Xiphinema Index Thorne & Allen on in vitro grape plants
Plant and Soil, 2011Co-Authors: Erwin Aballay, Anna Martensson, Paula PerssonAbstract:Xiphinema Index is the most aggressive root parasite affecting vines in Chile, controlled mainly chemically. The aim of this study was to identify rhizobacteria in grapevine roots growing in infested soils and to determine if some of these affect the parasitism caused by the nematode. Rhizobacteria of ungrafted grapevine cultivars from 11 vineyards were isolated using TSBA and identified with FAMEs analysis. The antagonistic effect to X. Index of those from soils 1 to 4 was assessed in 500 ml pots treating 2 months old in vitro plants with a bacterial suspension containing 1 × 106 c.f.u./ml and 400 nematodes, determining after 4 months growth nematode populations and root damages. Also culture filtrates were assessed. 400 isolates in 25 genera were obtained from the 11 vineyards. The most frequent species were Pseudomonas putida (35.1%), Escherichia coli (7.6%) and Pseudomonas fluorescens (6.1%). Isolates of soils 1 to 4, show that Bacillus megaterium, B. brevis, Pseudomonas corrugata, P. savastanoi, Stenotrophomonas maltophilia and Serratia plymuthica reduced root damage and suppressed populations, meanwhile strains of B. brevis and Comamonas acidovorans increased plant growth but did not control nematodes. It is concluded that these isolates may be useful in biological control programmes in vineyards.
