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Sample records for fastidiosa infecting grapes

  1. Comparative analysis of ESTs involved in grape responses to Xylella fastidiosa infection

    PubMed Central

    Lin, Hong; Doddapaneni, Harshavardhan; Takahashi, Yuri; Walker, M Andrew

    2007-01-01

    Background The gram-negative bacterium Xylella fastidiosa (Xf) is the causal agent of Pierce's disease (PD) in grape as well as diseases of many fruit and ornamental plants. The current molecular breeding efforts have identified genetic basis of PD resistance in grapes. However, the transcriptome level characterization of the host response to this pathogen is lacking. Results Twelve tissue specific subtractive suppression hybridization (SSH) cDNA libraries derived from a time course sampling scheme were constructed from stems, leaves and shoots of PD resistant and susceptible sibling genotypes (V. rupestris × V. arizonica) in response to Xf infection. A total of 5,794 sequences were obtained from these cDNA libraries from which 993 contigs and 949 singletons were derived. Using Gene Ontology (GO) hierarchy, the non-redundant sequences were classified into the three principal categories: molecular function (30%), cellular components (9%) and biological processes (7%). Comparative analysis found variations in EST expression pattern between infected and non-infected PD resistant and PD susceptible grape genotypes. Among the three tissues, libraries from stem tissues showed significant differences in transcript quality suggesting their important role in grape-Xylella interaction. Conclusion This study constitutes the first attempt to characterize the Vitis differential transcriptome associated with host-pathogen interactions from different explants and genotypes. All the generated ESTs have been submitted to GenBank and are also available through our website for further functional studies. PMID:17316447

  2. Transcriptional regulation of the grape cytochrome P450 monooxygenase gene CYP736B expression in response to Xylella fastidiosa infection

    PubMed Central

    2010-01-01

    Background Plant cytochrome P450 monooxygenases (CYP) mediate synthesis and metabolism of many physiologically important primary and secondary compounds that are related to plant defense against a range of pathogenic microbes and insects. To determine if cytochrome P450 monooxygenases are involved in defense response to Xylella fastidiosa (Xf) infection, we investigated expression and regulatory mechanisms of the cytochrome P450 monooxygenase CYP736B gene in both disease resistant and susceptible grapevines. Results Cloning of genomic DNA and cDNA revealed that the CYP736B gene was composed of two exons and one intron with GT as a donor site and AG as an acceptor site. CYP736B transcript was up-regulated in PD-resistant plants and down-regulated in PD-susceptible plants 6 weeks after Xf inoculation. However, CYP736B expression was very low in stem tissues at all evaluated time points. 5'RACE and 3'RACE sequence analyses revealed that there were three candidate transcription start sites (TSS) in the upstream region and three candidate polyadenylation (PolyA) sites in the downstream region of CYP736B. Usage frequencies of each transcription initiation site and each polyadenylation site varied depending on plant genotype, developmental stage, tissue, and treatment. These results demonstrate that expression of CYP736B is regulated developmentally and in response to Xf infection at both transcriptional and post-transcriptional levels. Multiple transcription start and polyadenylation sites contribute to regulation of CYP736B expression. Conclusions This report provides evidence that the cytochrome P450 monooxygenase CYP736B gene is involved in defense response at a specific stage of Xf infection in grapevines; multiple transcription initiation and polyadenylation sites exist for CYP736B in grapevine; and coordinative and selective use of transcription initiation and polyadenylation sites play an important role in regulation of CYP736B expression during growth

  3. Xylella fastidiosa infection of grapevines affects host secondary metabolite and defense-related protein levels within xylem

    USDA-ARS?s Scientific Manuscript database

    Pierce’s disease of grapevine is a serious threat to grape production and is caused by the xylem-dwelling bacterial pathogen Xylella fastidiosa. Microscopy studies have documented morphological changes to grapevine xylem due to infection by X. fastidiosa. Comparatively, less is known about the bi...

  4. Production of Xylella fastidiosa diffusible signal factor in transgenic grape causes pathogen confusion and reduction in severity of Pierce's disease.

    PubMed

    Lindow, Steven; Newman, Karyn; Chatterjee, Subhadeep; Baccari, Clelia; Lavarone, Anthony T; Ionescu, Michael

    2014-03-01

    The rpfF gene from Xylella fastidiosa, encoding the synthase for diffusible signal factor (DSF), was expressed in 'Freedom' grape to reduce the pathogen's growth and mobility within the plant. Symptoms in such plants were restricted to near the point of inoculation and incidence of disease was two- to fivefold lower than in the parental line. Both the longitudinal and lateral movement of X. fastidiosa in the xylem was also much lower. DSF was detected in both leaves and xylem sap of RpfF-expressing plants using biological sensors, and both 2-Z-tetradecenoic acid, previously identified as a component of X. fastidiosa DSF, and cis-11-methyl-2-dodecenoic acid were detected in xylem sap using electrospray ionization mass spectrometry. A higher proportion of X. fastidiosa cells adhered to xylem vessels of the RpfF-expressing line than parental 'Freedom' plants, reflecting a higher adhesiveness of the pathogen in the presence of DSF. Disease incidence in RpfF-expressing plants in field trials in which plants were either mechanically inoculated with X. fastidiosa or subjected to natural inoculation by sharpshooter vectors was two- to fourfold lower in than that of the parental line. The number of symptomatic leaves on infected shoots was reduced proportionally more than the incidence of infection, reflecting a decreased ability of X. fastidiosa to move within DSF-producing plants.

  5. Xylella fastidiosa infection of grapevines affects xylem levels of phenolic compounds and pathogenesis-related proteins

    USDA-ARS?s Scientific Manuscript database

    Pierce’s disease (PD), caused by the xylem-dwelling pathogen Xylella fastidiosa (X.f.), is a serious threat to grape production. The effects of X.f. infection six months post-inoculation on defense-associated proteins and phenolic compounds found in xylem sap and tissue were evaluated. Defense-assoc...

  6. Grapevine phenolics in xylem sap and tissues are significantly altered during infection by Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Pierce’s disease of grapevine (PD), caused by the bacterial pathogen Xylella fastidiosa (X.f.), remains a serious problem for grape production in California and elsewhere. This research examined induction of phenolic compounds in grapevines (cv. Thompson Seedless) infected with X.f. over a six month...

  7. Xylella fastidiosa Isolates from Both subsp. multiplex and fastidiosa Cause Disease on Southern Highbush Blueberry (Vaccinium sp.) Under Greenhouse Conditions.

    PubMed

    Oliver, J E; Cobine, P A; De La Fuente, L

    2015-07-01

    Xylella fastidiosa is a xylem-limited gram-negative plant pathogen that affects numerous crop species, including grape, citrus, peach, pecan, and almond. Recently, X. fastidiosa has also been found to be the cause of bacterial leaf scorch on blueberry in the southeastern United States. Thus far, all X. fastidiosa isolates obtained from infected blueberry have been classified as X. fastidiosa subsp. multiplex; however, X. fastidiosa subsp. fastidiosa isolates are also present in the southeastern United States and commonly cause Pierce's disease of grapevines. In this study, seven southeastern U.S. isolates of X. fastidiosa, including three X. fastidiosa subsp. fastidiosa isolates from grape, one X. fastidiosa subsp. fastidiosa isolate from elderberry, and three X. fastidiosa subsp. multiplex isolates from blueberry, were used to infect the southern highbush blueberry 'Rebel'. Following inoculation, all isolates colonized blueberry, and isolates from both X. fastidiosa subsp. multiplex and X. fastidiosa subsp. fastidiosa caused symptoms, including characteristic stem yellowing and leaf scorch symptoms as well as dieback of the stem tips. Two X. fastidiosa subsp. multiplex isolates from blueberry caused more severe symptoms than the other isolates examined, and infection with these two isolates also had a significant impact on host mineral nutrient content in sap and leaves. These findings have potential implications for understanding X. fastidiosa host adaptation and expansion and the development of emerging diseases caused by this bacterium.

  8. Grapevine phenolic compounds in xylem sap and tissues are significantly altered during infection by Xylella fastidiosa.

    PubMed

    Wallis, Christopher M; Chen, Jianchi

    2012-09-01

    Pierce's disease of grapevine (PD), caused by the bacterial pathogen Xylella fastidiosa, remains a serious problem for grape production in California and elsewhere. This research examined induction of phenolic compounds in grapevines ('Thompson Seedless') infected with X. fastidiosa over a 6-month period. Two months postinoculation with X. fastidiosa, catechin, digalloylquinic acid, and astringin were found at greater levels in xylem sap; multiple catechins, procyanidins, and stilbenoids were found at greater levels in xylem tissues; and precursors to lignin and condensed tannins were found at greater levels in xylem cell walls. However, such large-scale inductions of phenolic compounds were not observed 4 months after inoculation. Six months after inoculation, infected plants had significantly reduced phenolic levels in xylem sap and tissues when compared with control plants, including lowered levels of lignin and condensed tannins. At 6 months, PD symptoms were severe in infected plants and most photosynthetic tissue was abscised. These results suggest that, even though grapevine hosts may initially respond to X. fastidiosa infections with increased production of phenolic compounds, ultimately, PD causes grapevines to enter a state of decline whereby diseased hosts no longer have the resources to support secondary metabolite production, including defense-associated phenolic compounds.

  9. The role of Xylella fastidiosa cold shock proteins in Pierce’s disease of grapes

    USDA-ARS?s Scientific Manuscript database

    Pierce’s disease of grapevine, caused by the bacterial pathogen Xylella fastidiosa (Xf) is limited to warmer climates, and plant infection can be eliminated by cold winter conditions. Milder winters can increase the likelihood of pathogen persistence from one growing season to the next. Cold adaptat...

  10. The Bacterial Pathogen Xylella fastidiosa Affects the Leaf Ionome of Plant Hosts during Infection

    PubMed Central

    De La Fuente, Leonardo; Parker, Jennifer K.; Oliver, Jonathan E.; Granger, Shea; Brannen, Phillip M.; van Santen, Edzard; Cobine, Paul A.

    2013-01-01

    Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition) were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen. PMID:23667547

  11. The bacterial pathogen Xylella fastidiosa affects the leaf ionome of plant hosts during infection.

    PubMed

    De La Fuente, Leonardo; Parker, Jennifer K; Oliver, Jonathan E; Granger, Shea; Brannen, Phillip M; van Santen, Edzard; Cobine, Paul A

    2013-01-01

    Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition) were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen.

  12. Hyper-variation of Tandem Repeats at the PD0218 (pspB) locus of Xylella fastidiosa Almond Leaf Scorch and Grape Pierce’s Disease Strains

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a Gram negative plant pathogenic bacterium that causes almond leaf scorch disease (ALSD) and grape Pierce’s disease (PD) in California. A-genotype strains cause ALSD only. G-genotype strains cause both PD and ALSD. Little is known about how X. fastidiosa interacts with the envi...

  13. Genetic variation of Xylella fastidiosa associated with grape vines in two major viticulture regions in the United Sates: California and Texas

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf) causes Pierce’s disease in grapevine. Here, genetic diversity and population structure of grape strains of Xf collected from two important grape growing regions in the United States, California and Texas, is presented. Multilocus simple sequence repeat (SSR) markers revealed ...

  14. Diversity Evaluation of Xylella fastidiosa from Infected Olive Trees in Apulia (Southern Italy)

    PubMed Central

    Mang, Stefania M.; Frisullo, Salvatore; Elshafie, Hazem S.; Camele, Ippolito

    2016-01-01

    Olive culture is very important in the Mediterranean Basin. A severe outbreak of Olive Quick Decline Syndrome (OQDS) caused by Xylella fastidiosa infection was first noticed in 2013 on olive trees in the southern part of Apulia region (Lecce province, southern Italy). Studies were carried out for detection and diversity evaluation of the Apulian strain of Xylella fastidiosa. The presence of the pathogen in olive samples was detected by PCR amplifying the 16S rDNA, gyrase B subunit (gyrB) and HL hypothetical protein genes and single nucleotide polymorphisms (SNPs) assessment was performed to genotype X. fastidiosa. Twelve SNPs were recorded over gyrB and six SNPs were found for HL gene. Less variations were detected on 16S rDNA gene. Only gyrB and HL provided sufficient information for dividing the Apulian X. fastidiosa olive strains into subspecies. Using HL nucleotide sequences was possible to separate X. fastidiosa into subspecies pauca and fastidiosa. Whereas, nucleotide variation present on gyrB gene allowed separation of X. fastidiosa subsp. pauca from the other subspecies multiplex and fastidiosa. The X. fastidiosa strain from Apulia region was included into the subspecies pauca based on three genes phylogenetic analyses. PMID:27147930

  15. Diversity Evaluation of Xylella fastidiosa from Infected Olive Trees in Apulia (Southern Italy).

    PubMed

    Mang, Stefania M; Frisullo, Salvatore; Elshafie, Hazem S; Camele, Ippolito

    2016-04-01

    Olive culture is very important in the Mediterranean Basin. A severe outbreak of Olive Quick Decline Syndrome (OQDS) caused by Xylella fastidiosa infection was first noticed in 2013 on olive trees in the southern part of Apulia region (Lecce province, southern Italy). Studies were carried out for detection and diversity evaluation of the Apulian strain of Xylella fastidiosa. The presence of the pathogen in olive samples was detected by PCR amplifying the 16S rDNA, gyrase B subunit (gyrB) and HL hypothetical protein genes and single nucleotide polymorphisms (SNPs) assessment was performed to genotype X. fastidiosa. Twelve SNPs were recorded over gyrB and six SNPs were found for HL gene. Less variations were detected on 16S rDNA gene. Only gyrB and HL provided sufficient information for dividing the Apulian X. fastidiosa olive strains into subspecies. Using HL nucleotide sequences was possible to separate X. fastidiosa into subspecies pauca and fastidiosa. Whereas, nucleotide variation present on gyrB gene allowed separation of X. fastidiosa subsp. pauca from the other subspecies multiplex and fastidiosa. The X. fastidiosa strain from Apulia region was included into the subspecies pauca based on three genes phylogenetic analyses.

  16. Grapevines undergo varying shifts in secondary metabolic profiles when infected with Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Pierce’s disease (PD) is a devastating disease of grapevine caused by the bacterial pathogen Xylella fastidiosa (Xf). Key to the development and optimization of PD-tolerant grape cultivars is improved understanding about how grapevines defend themselves against Xf. This study complements histologica...

  17. Genome-wide Profiling and Analysis of the Vitis Transcriptome Responses to Xylella fastidiosa Infection

    USDA-ARS?s Scientific Manuscript database

    The gram-negative bacterium Xylella fastidiosa (Xf), vectored by xylem-feeding sharpshooters, is the causal agent of Pierce’s disease (PD) in grape. This disease causes serious economic losses in California. PD resistant plants produced by conventional or molecular breeding techniques are the ultima...

  18. Whole genome evaluation of tandem repeat polymorphisms between two pathogenically similar strains of Xylella fastidiosa isolated from almond and grape in California

    USDA-ARS?s Scientific Manuscript database

    Whole genome tandem repeat polymorphisms were evaluated between two closely related Xylella fastidiosa strains, M23 and Temecula1, both cause almond leaf scorch disease (ALSD) and grape Pierce’s disease (PD) in California. Strain M23 was isolated from almond and the genome was sequenced in this stu...

  19. New Coffee Plant-Infecting Xylella fastidiosa Variants Derived via Homologous Recombination

    PubMed Central

    Denancé, Nicolas; Legendre, Bruno; Morel, Emmanuelle; Briand, Martial; Mississipi, Stelly; Durand, Karine; Olivier, Valérie; Portier, Perrine; Poliakoff, Françoise; Crouzillat, Dominique

    2015-01-01

    Xylella fastidiosa is a xylem-limited phytopathogenic bacterium endemic to the Americas that has recently emerged in Asia and Europe. Although this bacterium is classified as a quarantine organism in the European Union, importation of plant material from contaminated areas and latent infection in asymptomatic plants have engendered its inevitable introduction. In 2012, four coffee plants (Coffea arabica and Coffea canephora) with leaf scorch symptoms growing in a confined greenhouse were detected and intercepted in France. After identification of the causal agent, this outbreak was eradicated. Three X. fastidiosa strains were isolated from these plants, confirming a preliminary identification based on immunology. The strains were characterized by multiplex PCR and by multilocus sequence analysis/typing (MLSA-MLST) based on seven housekeeping genes. One strain, CFBP 8073, isolated from C. canephora imported from Mexico, was assigned to X. fastidiosa subsp. fastidiosa/X. fastidiosa subsp. sandyi. This strain harbors a novel sequence type (ST) with novel alleles at two loci. The two other strains, CFBP 8072 and CFBP 8074, isolated from Coffea arabica imported from Ecuador, were allocated to X. fastidiosa subsp. pauca. These two strains shared a novel ST with novel alleles at two loci. These MLST profiles showed evidence of recombination events. We provide genome sequences for CFBP 8072 and CFBP 8073 strains. Comparative genomic analyses of these two genome sequences with publicly available X. fastidiosa genomes, including the Italian strain CoDiRO, confirmed these phylogenetic positions and provided candidate alleles for coffee plant adaptation. This study demonstrates the global diversity of X. fastidiosa and highlights the diversity of strains isolated from coffee plants. PMID:26712553

  20. New Coffee Plant-Infecting Xylella fastidiosa Variants Derived via Homologous Recombination.

    PubMed

    Jacques, Marie-Agnès; Denancé, Nicolas; Legendre, Bruno; Morel, Emmanuelle; Briand, Martial; Mississipi, Stelly; Durand, Karine; Olivier, Valérie; Portier, Perrine; Poliakoff, Françoise; Crouzillat, Dominique

    2015-12-28

    Xylella fastidiosa is a xylem-limited phytopathogenic bacterium endemic to the Americas that has recently emerged in Asia and Europe. Although this bacterium is classified as a quarantine organism in the European Union, importation of plant material from contaminated areas and latent infection in asymptomatic plants have engendered its inevitable introduction. In 2012, four coffee plants (Coffea arabica and Coffea canephora) with leaf scorch symptoms growing in a confined greenhouse were detected and intercepted in France. After identification of the causal agent, this outbreak was eradicated. Three X. fastidiosa strains were isolated from these plants, confirming a preliminary identification based on immunology. The strains were characterized by multiplex PCR and by multilocus sequence analysis/typing (MLSA-MLST) based on seven housekeeping genes. One strain, CFBP 8073, isolated from C. canephora imported from Mexico, was assigned to X. fastidiosa subsp. fastidiosa/X. fastidiosa subsp. sandyi. This strain harbors a novel sequence type (ST) with novel alleles at two loci. The two other strains, CFBP 8072 and CFBP 8074, isolated from Coffea arabica imported from Ecuador, were allocated to X. fastidiosa subsp. pauca. These two strains shared a novel ST with novel alleles at two loci. These MLST profiles showed evidence of recombination events. We provide genome sequences for CFBP 8072 and CFBP 8073 strains. Comparative genomic analyses of these two genome sequences with publicly available X. fastidiosa genomes, including the Italian strain CoDiRO, confirmed these phylogenetic positions and provided candidate alleles for coffee plant adaptation. This study demonstrates the global diversity of X. fastidiosa and highlights the diversity of strains isolated from coffee plants.

  1. Induction of phenolic compounds in response to Xylella fastidiosa infection in five different grapevine cultivars

    USDA-ARS?s Scientific Manuscript database

    Previously, Thompson seedless grapevines infected with Xylella fastidiosa (Xf), the causal agent of Pierce’s disease (PD), were observed to possess greater phenolic levels in xylem sap and tissues than non-infected plants shortly after inoculation. Plants often produce greater levels of phenolic com...

  2. Comparative genomic analysis of coffee-infecting Xylella fastidiosa strains isolated from Brazil.

    PubMed

    Barbosa, Deibs; Alencar, Valquíria Campos; Santos, Daiene Souza; de Freitas Oliveira, Ana Cláudia; de Souza, Alessandra A; Coletta-Filho, Helvecio D; de Oliveira, Regina Souza; Nunes, Luiz R

    2015-05-01

    Strains of Xylella fastidiosa constitute a complex group of bacteria that develop within the xylem of many plant hosts, causing diseases of significant economic importance, such as Pierce's disease in North American grapevines and citrus variegated chlorosis in Brazil. X. fastidiosa has also been obtained from other host plants, in direct correlation with the development of diseases, as in the case of coffee leaf scorch (CLS)--a disease with potential to cause severe economic losses to the Brazilian coffee industry. This paper describes a thorough genomic characterization of coffee-infecting X. fastidiosa strains, initially performed through a microarray-based approach, which demonstrated that CLS strains could be subdivided in two phylogenetically distinct subgroups. Whole-genomic sequencing of two of these bacteria (one from each subgroup) allowed identification of ORFs and horizontally transferred elements (HTEs) that were specific to CLS-related X. fastidiosa strains. Such analyses confirmed the size and importance of HTEs as major mediators of chromosomal evolution amongst these bacteria, and allowed identification of differences in gene content, after comparisons were made with previously sequenced X. fastidiosa strains, isolated from alternative hosts. Although direct experimentation still needs to be performed to elucidate the biological consequences associated with such differences, it was interesting to verify that CLS-related bacteria display variations in genes that produce toxins, as well as surface-related factors (such as fimbrial adhesins and LPS) that have been shown to be involved with recognition of specific host factors in different pathogenic bacteria.

  3. Microarray Analysis of Global Gene Expression of V. vinifera in Response to Xylella fastidiosa Infection

    USDA-ARS?s Scientific Manuscript database

    Previously, we analyzed gene expression profiles of Pierce’s Disease (PD) resistant and susceptible genotypes of V. arizonica hybrids in response to infection by X. fastidiosa (Xf). Here we report the gene expression profile of the PD susceptible European grapevine (V. vinifera) in response to Xf...

  4. Intersubspecific recombination in Xylella fastidiosa Strains native to the United States: infection of novel hosts associated with an unsuccessful invasion.

    PubMed

    Nunney, Leonard; Hopkins, Donald L; Morano, Lisa D; Russell, Stephanie E; Stouthamer, Richard

    2014-02-01

    The bacterial pathogen Xylella fastidiosa infects xylem and causes disease in many plant species in the Americas. Different subspecies of this bacterium and different genotypes within subspecies infect different plant hosts, but the genetics of host adaptation are unknown. Here we examined the hypothesis that the introduction of novel genetic variation via intersubspecific homologous recombination (IHR) facilitates host shifts. We investigated IHR in 33 X. fastidiosa subsp. multiplex isolates previously identified as recombinant based on 8 loci (7 multilocus sequence typing [MLST] loci plus 1 locus). We found significant evidence of introgression from X. fastidiosa subsp. fastidiosa in 4 of the loci and, using published data, evidence of IHR in 6 of 9 additional loci. Our data showed that IHR regions in 2 of the 4 loci were inconsistent (12 mismatches) with X. fastidiosa subsp. fastidiosa alleles found in the United States but consistent with alleles from Central America. The other two loci were consistent with alleles from both regions. We propose that the recombinant forms all originated via genomewide recombination of one X. fastidiosa subsp. multiplex ancestor with one X. fastidiosa subsp. fastidiosa donor from Central America that was introduced into the United States but subsequently disappeared. Using all of the available data, 5 plant hosts of the recombinant types were identified, 3 of which also supported non-IHR X. fastidiosa subsp. multiplex, but 2 were unique to recombinant types from blueberry (7 isolates from Georgia, 3 from Florida); and blackberry (1 each from Florida and North Carolina), strongly supporting the hypothesis that IHR facilitated a host shift to blueberry and possibly blackberry.

  5. Specific Detection and Identification of American Mulberry-Infecting and Italian Olive-Associated Strains of Xylella fastidiosa by Polymerase Chain Reaction

    PubMed Central

    Guan, Wei; Shao, Jonathan; Elbeaino, Toufic; Davis, Robert E.; Zhao, Tingchang; Huang, Qi

    2015-01-01

    Xylella fastidiosa causes bacterial leaf scorch in many landscape trees including elm, oak, sycamore and mulberry, but methods for specific identification of a particular tree host species-limited strain or differentiation of tree-specific strains are lacking. It is also unknown whether a particular landscape tree-infecting X. fastidiosa strain is capable of infecting multiple landscape tree species in an urban environment. We developed two PCR primers specific for mulberry-infecting strains of X. fastidiosa based on the nucleotide sequence of a unique open reading frame identified only in mulberry-infecting strains among all the North and South American strains of X. fastidiosa sequenced to date. PCR using the primers allowed for detection and identification of mulberry-infecting X. fastidiosa strains in cultures and in samples collected from naturally infected mulberry trees. In addition, no mixed infections with or non-specific detections of the mulberry-infecting strains of X. fastidiosa were found in naturally X. fastidiosa-infected oak, elm and sycamore trees growing in the same region where naturally infected mulberry trees were grown. This genotype-specific PCR assay will be valuable for disease diagnosis, studies of strain-specific infections in insects and plant hosts, and management of diseases caused by X. fastidiosa. Unexpectedly but interestingly, the unique open reading frame conserved in the mulberry-infecting strains in the U. S. was also identified in the recently sequenced olive-associated strain CoDiRO isolated in Italy. When the primer set was tested against naturally infected olive plant samples collected in Italy, it allowed for detection of olive-associated strains of X. fastidiosa in Italy. This PCR assay, therefore, will also be useful for detection and identification of the Italian group of X. fastidiosa strains to aid understanding of the occurrence, evolution and biology of this new group of X. fastidiosa strains. PMID:26061051

  6. Specific Detection and Identification of American Mulberry-Infecting and Italian Olive-Associated Strains of Xylella fastidiosa by Polymerase Chain Reaction.

    PubMed

    Guan, Wei; Shao, Jonathan; Elbeaino, Toufic; Davis, Robert E; Zhao, Tingchang; Huang, Qi

    2015-01-01

    Xylella fastidiosa causes bacterial leaf scorch in many landscape trees including elm, oak, sycamore and mulberry, but methods for specific identification of a particular tree host species-limited strain or differentiation of tree-specific strains are lacking. It is also unknown whether a particular landscape tree-infecting X. fastidiosa strain is capable of infecting multiple landscape tree species in an urban environment. We developed two PCR primers specific for mulberry-infecting strains of X. fastidiosa based on the nucleotide sequence of a unique open reading frame identified only in mulberry-infecting strains among all the North and South American strains of X. fastidiosa sequenced to date. PCR using the primers allowed for detection and identification of mulberry-infecting X. fastidiosa strains in cultures and in samples collected from naturally infected mulberry trees. In addition, no mixed infections with or non-specific detections of the mulberry-infecting strains of X. fastidiosa were found in naturally X. fastidiosa-infected oak, elm and sycamore trees growing in the same region where naturally infected mulberry trees were grown. This genotype-specific PCR assay will be valuable for disease diagnosis, studies of strain-specific infections in insects and plant hosts, and management of diseases caused by X. fastidiosa. Unexpectedly but interestingly, the unique open reading frame conserved in the mulberry-infecting strains in the U. S. was also identified in the recently sequenced olive-associated strain CoDiRO isolated in Italy. When the primer set was tested against naturally infected olive plant samples collected in Italy, it allowed for detection of olive-associated strains of X. fastidiosa in Italy. This PCR assay, therefore, will also be useful for detection and identification of the Italian group of X. fastidiosa strains to aid understanding of the occurrence, evolution and biology of this new group of X. fastidiosa strains.

  7. Evaluation of Arabidopsis thaliana as a model host for Xylella fastidiosa.

    PubMed

    Rogers, Elizabeth E

    2012-06-01

    The bacterium Xylella fastidiosa causes a number of plant diseases of significant economic impact. To date, progress determining mechanisms of host-plant susceptibility, tolerance, or resistance has been slow, due in large part to the long generation time and limited available genetic resources for grape, almond, and other known hosts of X. fastidiosa. To overcome many of these limitations, Arabidopsis thaliana has been evaluated as a host for X. fastidiosa. A pin-prick inoculation method has been developed to infect Arabidopsis with X. fastidiosa. Following infection, X. fastidiosa multiplies and can be detected by microscopy, polymerase chain reaction, and isolation. The ecotypes Van-0, LL-0, and Tsu-1 all allow more growth of strain X. fastidiosa Temecula than the reference ecotype Col-0. Affymetrix ATH1 microarray analysis of inoculated vs. noninoculated Tsu-1 reveals gene expression changes that differ greatly from changes seen after infection with apoplast-colonizing bacteria such as Psuedomonas syringae pvs. tomato or syringae. Many genes responsive to oxidative stress are differentially regulated, while classic pathogenesis-related genes are not induced by X. fastidiosa infection.

  8. Ionome changes in Xylella fastidiosa-infected Nicotiana tabacum correlate with virulence and discriminate between subspecies of bacterial isolates.

    PubMed

    Oliver, J E; Sefick, S A; Parker, J K; Arnold, T; Cobine, P A; De La Fuente, L

    2014-10-01

    Characterization of ionomes has been used to uncover the basis of nutrient utilization and environmental adaptation of plants. Here, ionomic profiles were used to understand the phenotypic response of a plant to infection by genetically diverse isolates of Xylella fastidiosa, a gram-negative, xylem-limited bacterial plant pathogen. In this study, X. fastidiosa isolates were used to infect a common model host (Nicotiana tabacum 'SR1'), and leaf and sap concentrations of eleven elements together with plant colonization and symptoms were assessed. Multivariate statistical analysis revealed that changes in the ionome were significantly correlated with symptom severity and bacterial populations in host petioles. Moreover, plant ionome modification by infection could be used to differentiate the X. fastidiosa subspecies with which the plant was infected. This report establishes host ionome modification as a phenotypic response to infection.

  9. Transcriptome analysis of the phytobacterium Xylella fastidiosa growing under xylem-based chemical conditions.

    PubMed

    Ciraulo, Maristela Boaceff; Santos, Daiene Souza; Rodrigues, Ana Claudia de Freitas Oliveira; de Oliveira, Marcus Vinícius; Rodrigues, Tiago; de Oliveira, Regina Costa; Nunes, Luiz R

    2010-01-01

    Xylella fastidiosa is a xylem-limited bacterium responsible for important plant diseases, like citrus-variegated chlorosis (CVC) and grapevine Pierce's disease (PD). Interestingly, in vitro growth of X. fastidiosa in chemically defined media that resemble xylem fluid has been achieved, allowing studies of metabolic processes used by xylem-dwelling bacteria to thrive in such nutrient-poor conditions. Thus, we performed microarray hybridizations to compare transcriptomes of X. fastidiosa cells grown in 3G10-R, a medium that resembles grape sap, and in Periwinkle Wilt (PW), the complex medium traditionally used to cultivate X. fastidiosa. We identified 299 transcripts modulated in response to growth in these media. Some 3G10R-overexpressed genes have been shown to be upregulated in cells directly isolated from infected plants and may be involved in plant colonization, virulence and environmental competition. In contrast, cells cultivated in PW show a metabolic switch associated with increased aerobic respiration and enhanced bacterial growth rates.

  10. Comparative analyses of the complete genome sequences of Pierce's disease and citrus variegated chlorosis strains of Xylella fastidiosa.

    PubMed

    Van Sluys, M A; de Oliveira, M C; Monteiro-Vitorello, C B; Miyaki, C Y; Furlan, L R; Camargo, L E A; da Silva, A C R; Moon, D H; Takita, M A; Lemos, E G M; Machado, M A; Ferro, M I T; da Silva, F R; Goldman, M H S; Goldman, G H; Lemos, M V F; El-Dorry, H; Tsai, S M; Carrer, H; Carraro, D M; de Oliveira, R C; Nunes, L R; Siqueira, W J; Coutinho, L L; Kimura, E T; Ferro, E S; Harakava, R; Kuramae, E E; Marino, C L; Giglioti, E; Abreu, I L; Alves, L M C; do Amaral, A M; Baia, G S; Blanco, S R; Brito, M S; Cannavan, F S; Celestino, A V; da Cunha, A F; Fenille, R C; Ferro, J A; Formighieri, E F; Kishi, L T; Leoni, S G; Oliveira, A R; Rosa, V E; Sassaki, F T; Sena, J A D; de Souza, A A; Truffi, D; Tsukumo, F; Yanai, G M; Zaros, L G; Civerolo, E L; Simpson, A J G; Almeida, N F; Setubal, J C; Kitajima, J P

    2003-02-01

    Xylella fastidiosa is a xylem-dwelling, insect-transmitted, gamma-proteobacterium that causes diseases in many plants, including grapevine, citrus, periwinkle, almond, oleander, and coffee. X. fastidiosa has an unusually broad host range, has an extensive geographical distribution throughout the American continent, and induces diverse disease phenotypes. Previous molecular analyses indicated three distinct groups of X. fastidiosa isolates that were expected to be genetically divergent. Here we report the genome sequence of X. fastidiosa (Temecula strain), isolated from a naturally infected grapevine with Pierce's disease (PD) in a wine-grape-growing region of California. Comparative analyses with a previously sequenced X. fastidiosa strain responsible for citrus variegated chlorosis (CVC) revealed that 98% of the PD X. fastidiosa Temecula genes are shared with the CVC X. fastidiosa strain 9a5c genes. Furthermore, the average amino acid identity of the open reading frames in the strains is 95.7%. Genomic differences are limited to phage-associated chromosomal rearrangements and deletions that also account for the strain-specific genes present in each genome. Genomic islands, one in each genome, were identified, and their presence in other X. fastidiosa strains was analyzed. We conclude that these two organisms have identical metabolic functions and are likely to use a common set of genes in plant colonization and pathogenesis, permitting convergence of functional genomic strategies.

  11. Seasonal increase of Xylella fastidiosa in hemiptera collected from central Texas vineyards.

    PubMed

    Mitchell, Forrest L; Brady, Jeff; Bextine, Blake; Lauzière, Isabelle

    2009-10-01

    Yellow sticky traps were placed in six vineyards in central Texas from 2003 to 2006 and in locations outside the vineyards in 2004-2006. In total, 72 collections on 55 dates were examined. Xylem fluid-feeding insects were removed and identified to species and then analyzed by polymerase chain reaction to determine the presence or absence of Xylella fastidiosa Wells et al. Of the 1318 insects removed, 13 species were found, dominated by Homalodisca vitripennis (Germar), Clastoptera xanthocepahala Germar, and Graphocephala versuta (Say). Insects testing positive for X. fastidiosa were analyzed further using fluorescence resonance energy transfer probes to determine the genotype of the bacterium, which fell into four groups: subspecies fastidiosa, multiplex, sandyi, and unknown subspecies. Vineyards known to be affected by Pierce's disease had more insects that were contaminated by the bacterium than those that were not as affected. X. fastidiosa subsp. fastidiosa, the causative agent of Pierce's disease, was found more commonly in insects collected from vineyards than from insects collected outside the vineyards. Conversely, the subspecies multiplex and sandyi, which are not known to cause disease in grape, were more commonly found in insects collected outside the vineyard. The percentage of individuals contaminated with the bacterium increased over the course of the growing season, and the data suggest that vector insects acquired X. fastidiosa subsp. fastidiosa from infected grapevines, a necessary precursor for vine to vine transmission to occur. Management options, including the use of systemic insecticides and plant roguing, would be effective for this type of transmission model.

  12. Grape Cultivar and Sap Culture Conditions Affect the Development of Xylella fastidiosa Phenotypes Associated with Pierce's Disease

    PubMed Central

    Hoch, Harvey C.; Burr, Thomas J.; Mowery, Patricia

    2016-01-01

    Xylella fastidiosa is a xylem-limited bacterium in plant hosts and causes Pierce’s disease (PD) of grapevines, which differ in susceptibility according to the Vitis species (spp.). In this work we compared X. fastidiosa biofilm formation and population dynamics when cultured in xylem saps from PD-susceptible and -resistant Vitis spp. under different conditions. Behaviors in a closed-culture system were compared to those in different sap-renewal cultures that would more closely mimic the physicochemical environment encountered in planta. Significant differences in biofilm formation and growth in saps from PD-susceptible and -resistant spp. were only observed using sap renewal culture. Compared to saps from susceptible V. vinifera, those from PD-resistant V. aestivalis supported lower titers of X. fastidiosa and less biofilm and V. champinii suppressed both growth and biofilm formation, behaviors which are correlated with disease susceptibility. Furthermore, in microfluidic chambers X. fastidiosa formed thick mature biofilm with three-dimensional (3-D) structures, such as pillars and mounds, in saps from all susceptible spp. In contrast, only small aggregates of various shapes were formed in saps from four out of five of the resistant spp.; sap from the resistant spp. V. mustangensis was an exception in that it also supported thick lawns of biofilm but not the above described 3-D structures typically seen in a mature biofilm from the susceptible saps. Our findings provide not only critical technical information for future bioassays, but also suggest further understanding of PD susceptibility. PMID:27508296

  13. Seasonal fluctuations of sap-feeding insect species infected by Xylella fastidiosa in apulian olive groves of southern Italy

    USDA-ARS?s Scientific Manuscript database

    A study on seasonal abundance and infectivity by Xylella fastidiosa of Auchenorrhyncha species in the Apulia region of Italy was conducted to identify ideal periods for monitoring and adoption of potential control measures against insect vectors. Adult populations of Auchenorrhyncha species were mon...

  14. Association of Xylella fastidiosa with Yield Loss and Altered Fruit Quality in a Naturally Infected Rabbiteye Blueberry Orchard

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa causes disease in a number of plants in the southeastern United States, including southern highbush blueberry, but little was known concerning its potential impact in rabbiteye blueberry (Vaccinium virgatum). In a naturally infected orchard in Louisiana, mean yields of X. fastidi...

  15. Spatial Genetic Structure of Coffee-Associated Xylella fastidiosa Populations Indicates that Cross Infection Does Not Occur with Sympatric Citrus Orchards.

    PubMed

    Francisco, Carolina S; Ceresini, Paulo C; Almeida, Rodrigo P P; Coletta-Filho, Helvécio D

    2017-04-01

    Xylella fastidiosa, an economically important plant-pathogenic bacterium, infects both coffee and citrus trees in Brazil. Although X. fastidiosa in citrus is well studied, knowledge about the population structure of this bacterium infecting coffee remains unknown. Here, we studied the population structure of X. fastidiosa infecting coffee trees in São Paulo State, Brazil, in four regions where citrus is also widely cultivated. Genotyping of over 500 isolates from coffee plants using 14 genomic microsatellite markers indicated that populations were largely geographically isolated, as previously found with populations of X. fastidiosa infecting citrus. These results were supported by a clustering analysis, which indicated three major genetic groups among the four sampled regions. Overall, approximately 38% of isolates showed significant membership coefficients not related to their original geographical populations (i.e., migrants), characterizing a significant degree of genotype flow among populations. To determine whether admixture occurred between isolates infecting citrus and coffee plants, one site with citrus and coffee orchards adjacent to each other was selected; over 100 isolates were typed from each host plant. No signal of natural admixture between citrus- and coffee-infecting isolates was found; artificial cross-infection assays with representative isolates also yielded no successful cross infection. A comparison determined that X. fastidiosa populations from coffee have higher genetic diversity and allelic richness compared with citrus. The results showed that coffee and citrus X. fastidiosa populations are effectively isolated from each other and, although coffee populations are spatially structured, migration has an important role in shaping diversity.

  16. Citrus Functional Genomics and Molecular Modeling in Relation to Citrus sinensis (Sweet Orange) Infection with Xylella fastidiosa (Citrus Variegated Chlorosis).

    PubMed

    Dwivedi, Upendra N; Tiwari, Sameeksha; Prasanna, Pragya; Awasthi, Manika; Singh, Swati; Pandey, Veda P

    2016-08-01

    Citrus are among the economically most important fruit tree crops in the world. Citrus variegated chlorosis (CVC), caused by Xylella fastidiosa infection, is a serious disease limiting citrus production at a global scale. With availability of citrus genomic resources, it is now possible to compare citrus expressed sequence tag (EST) data sets and identify single-nucleotide polymorphisms (SNPs) within and among different citrus cultivars that can be exploited for citrus resistance to infections, citrus breeding, among others. We report here, for the first time, SNPs in the EST data sets of X. fastidiosa-infected Citrus sinensis (sweet orange) and their functional annotation that revealed the involvement of eight C. sinensis candidate genes in CVC pathogenesis. Among these genes were xyloglucan endotransglycosylase, myo-inositol-1-phosphate synthase, and peroxidase were found to be involved in plant cell wall metabolism. These have been further investigated by molecular modeling for their role in CVC infection and defense. Molecular docking analyses of the wild and the mutant (SNP containing) types of the selected three enzymes with their respective substrates revealed a significant decrease in the binding affinity of substrates for the mutant enzymes, thus suggesting a decrease in the catalytic efficiency of these enzymes during infection, thereby facilitating a favorable condition for infection by the pathogen. These findings offer novel agrigenomics insights in developing future molecular targets and strategies for citrus fruit cultivation in ways that are resistant to X. fastidiosa infection, and by extension, with greater harvesting efficiency and economic value.

  17. Transmission of Xylella fastidiosa to grapevines by Homalodisca coagulata (Hemiptera: Cicadellidae).

    PubMed

    Almeida, Rodrigo P P; Purcell, Alexander H

    2003-04-01

    Pierce's disease (PD) of grapevines is caused by a xylem-limited bacterium Xylella fastidiosa (Wells, Raju, Hung, Weisburg, Mandelco-Paul, and Brenner) that is transmitted to plants by xylem sap-feeding insects. The introduction of the sharpshooter leafhopper Homalodisca coagulata (Say) into California has initiated new PD epidemics in southern California. In laboratory experiments, the major characteristics of H. coagulata's transmission of X. fastidiosa to grapevines were the same as reported for other vectors: short or absent latent period; nymphs transmitted but lost infectivity after molting and regained infectivity after feeding on infected plants; and infectivity persisted in adults. Adult H. coagulata acquired and inoculated X. fastidiosa in <1 h of access time on a plant. Inoculation rates increased with access time, but acquisition efficiency (20% per individual) did not increase significantly beyond 6-h access. Estimated inoculation efficiency per individual per day was 19.6, 17.9, and 10.3% for experiments where plant access was 1, 2, and 4 d, respectively. Freshly molted adults and nymphs acquired and transmitted X. fastidiosa more efficiently than did older, field-collected insects. H. coagulata transmitted X. fastidiosa to 2-yr-old woody tissues of grapevines as efficiently as to green shoots. H. coagulata transmitted X. fastidiosa 3.5 mo after acquisition, demonstrating persistence of infectivity in adults. About half (14/29) of the H. coagulata from which we failed to culture X. fostidiosa from homogenized heads (with a detection threshold of 265 CFU/head) transmitted the pathogen to grape, and 17 of 24 from which we cultured X. fastidiosa transmitted.

  18. Identification of potential protein markers of noble rot infected grapes.

    PubMed

    Lorenzini, Marilinda; Millioni, Renato; Franchin, Cinzia; Zapparoli, Giacomo; Arrigoni, Giorgio; Simonato, Barbara

    2015-07-15

    The evaluation of Botrytis cinerea as noble rot on withered grapes is of great importance to predict the wine sensory/organoleptic properties and to manage the winemaking process of Amarone, a passito dry red wine. This report describes the first proteomic analysis of grapes infected by noble rot under withering conditions to identify possible markers of fungal infection. 2-D gel electrophoresis revealed that protein profiles of infected and not infected grape samples are significantly different in terms of number of spots and relative abundance. Protein identification by MS analysis allowed to identify only in infected berries proteins of B. cinerea that represent potential markers of the presence of the fungus in the withered grapes.

  19. Lack of evidence for transmission of Xylella fastidiosa from infected sweet orange seed

    USDA-ARS?s Scientific Manuscript database

    Citrus variegated chlorosis is among the principle diseases that affect sweet orange in Brazil and Argentina, and is viewed as an emerging threat by the U.S. sweet orange industry. The disease is caused by the fastidious bacterium Xylella fastidiosa, and can be transmitted by both leafhopper insect...

  20. Specific detection and identification of mulberry-infecting strains of Xylella fastidiosa by polymerase chain reaction

    USDA-ARS?s Scientific Manuscript database

    X. fastidiosa causes bacterial leaf scorch in many landscape trees including elm, oak, sycamore and mulberry, but methods for specific identification of a particular tree host species-limited strain or differentiation of tree-specific strains are lacking. It is also unknown whether a particular land...

  1. Draft Genome Sequence of CO33, a Coffee-Infecting Isolate of Xylella fastidiosa

    PubMed Central

    Loconsole, Giuliana; Boscia, Donato; Calzolari, Alessandra; Chiumenti, Michela; Martelli, Giovanni P.; Saldarelli, Pasquale; Almeida, Rodrigo P. P.; Saponari, Maria

    2015-01-01

    The draft genome sequence of Xylella fastidiosa CO33 isolate, retrieved from symptomatic leaves of coffee plant intercepted in northern Italy, is reported. The CO33 genome size is 2,681,926 bp with a GC content of 51.7%. PMID:26679584

  2. Initial genetic analysis of Xylella fastidiosa in Texas.

    PubMed

    Morano, Lisa D; Bextine, Blake R; Garcia, Dennis A; Maddox, Shermel V; Gunawan, Stanley; Vitovsky, Natalie J; Black, Mark C

    2008-04-01

    Xylella fastidiosa is the causative agent of Pierce's Disease of grape. No published record of X. fastidiosa genetics in Texas exists despite growing financial risk to the U.S. grape industry, a Texas population of the glassy-winged sharpshooter insect vector (Homalodisca vitripennis) now spreading in California, and evidence that the bacterium is ubiquitous to southern states. Using sequences of conserved gyrB and mopB genes, we have established at least two strains in Texas, grape strain and ragweed strain, corresponding genetically with subsp. piercei and multiplex, respectively. The grape strain in Texas is found in Vitis vinifera varieties, hybrid vines, and wild Vitis near vineyards, whereas the ragweed strain in Texas is found in annuals, shrubs, and trees near vineyards or other areas. RFLP and QRT PCR techniques were used to differentiate grape and ragweed strains with greater efficiency than sequencing and are practical for screening numerous X. fastidiosa isolates for clade identity.

  3. RNA-Seq analysis of Citrus reticulata in the early stages of Xylella fastidiosa infection reveals auxin-related genes as a defense response.

    PubMed

    Rodrigues, Carolina M; de Souza, Alessandra A; Takita, Marco A; Kishi, Luciano T; Machado, Marcos A

    2013-10-03

    Citrus variegated chlorosis (CVC), caused by Xylella fastidiosa, is one the most important citrus diseases, and affects all varieties of sweet orange (Citrus sinensis L. Osb). On the other hand, among the Citrus genus there are different sources of resistance against X. fastidiosa. For these species identifying these defense genes could be an important step towards obtaining sweet orange resistant varieties through breeding or genetic engineering. To assess these genes we made use of mandarin (C. reticulata Blanco) that is known to be resistant to CVC and shares agronomical characteristics with sweet orange. Thus, we investigated the gene expression in Ponkan mandarin at one day after infection with X. fastidiosa, using RNA-seq. A set of genes considered key elements in the resistance was used to confirm its regulation in mandarin compared with the susceptible sweet orange. Gene expression analysis of mock inoculated and infected tissues of Ponkan mandarin identified 667 transcripts repressed and 724 significantly induced in the later. Among the induced transcripts, we identified genes encoding proteins similar to Pattern Recognition Receptors. Furthermore, many genes involved in secondary metabolism, biosynthesis and cell wall modification were upregulated as well as in synthesis of abscisic acid, jasmonic acid and auxin. This work demonstrated that the defense response to the perception of bacteria involves cell wall modification and activation of hormone pathways, which probably lead to the induction of other defense-related genes. We also hypothesized the induction of auxin-related genes indicates that resistant plants initially recognize X. fastidiosa as a necrotrophic pathogen.

  4. Detection and Analysis of the Bacterium, Xylella fastidiosa, in Glassy-Winged Sharpshooter, Homalodisca vitripennis, Populations in Texas

    PubMed Central

    Hail, Daymon; Mitchell, Forrest; Lauzière, Isabelle; Marshall, Patrick; Brady, Jeff; Bextine, Blake

    2010-01-01

    The glassy-winged sharpshooter, Homalodisca vitripeninis Germar (Hemiptera: Cicadellidae), is a xylophagous insect that is an endemic pest of several economically important plants in Texas. H. vitripennis is the main vector of Xylella fastidiosa Wells (Xanthomonadales: Xanthomonadaceae), the bacterium that causes Pierce's disease of grapevine and can travel long distances putting much of Texas grape production at risk. Understanding the movement of H. vitripennis populations capable of transmitting X. fastidiosa into Pierce's-disease-free areas is critical for developing a management program for Pierce's disease. To that end, the USDA-APHIS has developed a program to sample vineyards across Texas to monitor populations of H. vitripennis. From this sampling, H vitripennis collected during 2005 and 2006 over the months of May, June, and July from eight vineyards in different regions of Texas were recovered from yellow sticky traps and tested for the presence of X. fastidiosa. The foregut contents were vacuum extracted and analyzed using RT-PCR to determine the percentage of H. vitripennis within each population that harbor X. fastidiosa and have the potential to transmit this pathogen. H. vitripennis from vineyards known to have Pierce's disease routinely tested positive for the presence of X. fastidiosa. While almost all H. vitripennis collected from vineyards with no history of Pierce's disease tested negative for the presence of the pathogen, three individual insects tested positive. Furthermore, all three insects were determined, by DNA sequencing, to be carrying a strain of X. fastidiosa homologous to known Pierce's disease strains, signifying them as a risk factor for new X. fastidiosa infections. PMID:21062210

  5. Detection and analysis of the bacterium, Xylella fastidiosa, in glassy-winged sharpshooter, Homalodisca vitripennis, populations in Texas.

    PubMed

    Hail, Daymon; Mitchell, Forrest; Lauzière, Isabelle; Marshall, Patrick; Brady, Jeff; Bextine, Blake

    2010-01-01

    The glassy-winged sharpshooter, Homalodisca vitripeninis Germar (Hemiptera: Cicadellidae), is a xylophagous insect that is an endemic pest of several economically important plants in Texas. H. vitripennis is the main vector of Xylella fastidiosa Wells (Xanthomonadales: Xanthomonadaceae), the bacterium that causes Pierce's disease of grapevine and can travel long distances putting much of Texas grape production at risk. Understanding the movement of H. vitripennis populations capable of transmitting X. fastidiosa into Pierce's-disease-free areas is critical for developing a management program for Pierce's disease. To that end, the USDA-APHIS has developed a program to sample vineyards across Texas to monitor populations of H. vitripennis. From this sampling, H vitripennis collected during 2005 and 2006 over the months of May, June, and July from eight vineyards in different regions of Texas were recovered from yellow sticky traps and tested for the presence of X. fastidiosa. The foregut contents were vacuum extracted and analyzed using RT-PCR to determine the percentage of H. vitripennis within each population that harbor X. fastidiosa and have the potential to transmit this pathogen. H. vitripennis from vineyards known to have Pierce's disease routinely tested positive for the presence of X. fastidiosa. While almost all H. vitripennis collected from vineyards with no history of Pierce's disease tested negative for the presence of the pathogen, three individual insects tested positive. Furthermore, all three insects were determined, by DNA sequencing, to be carrying a strain of X. fastidiosa homologous to known Pierce's disease strains, signifying them as a risk factor for new X. fastidiosa infections.

  6. Characterization of a diffusible signaling factor from Xylella fastidiosa.

    PubMed

    Beaulieu, Ellen D; Ionescu, Michael; Chatterjee, Subhadeep; Yokota, Kenji; Trauner, Dirk; Lindow, Steven

    2013-01-08

    Cell-cell signaling in Xylella fastidiosa has been implicated in the coordination of traits enabling colonization in plant hosts as well as insect vectors. This cell density-dependent signaling has been attributed to a diffusible signaling factor (DSF) produced by the DSF synthase RpfF. DSF produced by related bacterial species are unsaturated fatty acids, but that of X. fastidiosa was thought to be different from those of other taxa. We describe here the isolation and characterization of an X. fastidiosa DSF (XfDSF) as 2(Z)-tetradecenoic acid. This compound was isolated both from recombinant Erwinia herbicola expressing X. fastidiosa rpfF and from an X. fastidiosa rpfC deletion mutant that overproduces DSF. Since an rpfF mutant is impaired in biofilm formation and underexpresses the hemagglutinin-like protein-encoding genes hxfA and hxfB, we demonstrate that these traits can be restored by ca. 0.5 µM XfDSF but not by myristic acid, the fully saturated tetradecenoic acid. A phoA-based X. fastidiosa biosensor that assesses DSF-dependent expression of hxfA or hxfB revealed a high level of molecular specificity of DSF signaling. X. fastidiosa causes diseases in many important plants, including grape, where it incites Pierce's disease. Virulence of X. fastidiosa for grape is coordinated by cell-cell signaling molecules, designated DSF (Diffusible Signaling Factor). Mutants blocked in DSF production are hypervirulent for grape, suggesting that virulence is suppressed upon DSF accumulation and that disease could be controlled by artificial elevation of the DSF level in plants. In this work, we describe the isolation of the DSF produced by X. fastidiosa and the verification of its biological activity as an antivirulence factor. We also have developed X. fastidiosa DSF biosensors to evaluate the specificity of cell-cell signaling to be investigated.

  7. Cell Wall-Degrading Enzymes Enlarge the Pore Size of Intervessel Pit Membranes in Healthy and Xylella fastidiosa-Infected Grapevines1[C][W][OA

    PubMed Central

    Pérez-Donoso, Alonso G.; Sun, Qiang; Roper, M. Caroline; Greve, L. Carl; Kirkpatrick, Bruce; Labavitch, John M.

    2010-01-01

    The pit membrane (PM) is a primary cell wall barrier that separates adjacent xylem water conduits, limiting the spread of xylem-localized pathogens and air embolisms from one conduit to the next. This paper provides a characterization of the size of the pores in the PMs of grapevine (Vitis vinifera). The PM porosity (PMP) of stems infected with the bacterium Xylella fastidiosa was compared with the PMP of healthy stems. Stems were infused with pressurized water and flow rates were determined; gold particles of known size were introduced with the water to assist in determining the size of PM pores. The effect of introducing trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid (CDTA), oligogalacturonides, and polygalacturonic acid into stems on water flux via the xylem was also measured. The possibility that cell wall-degrading enzymes could alter the pore sizes, thus facilitating the ability of X. fastidiosa to cross the PMs, was tested. Two cell wall-degrading enzymes likely to be produced by X. fastidiosa (polygalactuoronase and endo-1,4- β -glucanase) were infused into stems, and particle passage tests were performed to check for changes in PMP. Scanning electron microscopy of control and enzyme-infused stem segments revealed that the combination of enzymes opened holes in PMs, probably explaining enzyme impacts on PMP and how a small X. fastidiosa population, introduced into grapevines by insect vectors, can multiply and spread throughout the vine and cause Pierce's disease. PMID:20107028

  8. Cell wall-degrading enzymes enlarge the pore size of intervessel pit membranes in healthy and Xylella fastidiosa-infected grapevines.

    PubMed

    Pérez-Donoso, Alonso G; Sun, Qiang; Roper, M Caroline; Greve, L Carl; Kirkpatrick, Bruce; Labavitch, John M

    2010-03-01

    The pit membrane (PM) is a primary cell wall barrier that separates adjacent xylem water conduits, limiting the spread of xylem-localized pathogens and air embolisms from one conduit to the next. This paper provides a characterization of the size of the pores in the PMs of grapevine (Vitis vinifera). The PM porosity (PMP) of stems infected with the bacterium Xylella fastidiosa was compared with the PMP of healthy stems. Stems were infused with pressurized water and flow rates were determined; gold particles of known size were introduced with the water to assist in determining the size of PM pores. The effect of introducing trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA), oligogalacturonides, and polygalacturonic acid into stems on water flux via the xylem was also measured. The possibility that cell wall-degrading enzymes could alter the pore sizes, thus facilitating the ability of X. fastidiosa to cross the PMs, was tested. Two cell wall-degrading enzymes likely to be produced by X. fastidiosa (polygalactuoronase and endo-1,4- beta -glucanase) were infused into stems, and particle passage tests were performed to check for changes in PMP. Scanning electron microscopy of control and enzyme-infused stem segments revealed that the combination of enzymes opened holes in PMs, probably explaining enzyme impacts on PMP and how a small X. fastidiosa population, introduced into grapevines by insect vectors, can multiply and spread throughout the vine and cause Pierce's disease.

  9. Transcriptome Analysis of the Phytobacterium Xylella fastidiosa Growing under Xylem-Based Chemical Conditions

    PubMed Central

    Ciraulo, Maristela Boaceff; Santos, Daiene Souza; Rodrigues, Ana Claudia de Freitas Oliveira; de Oliveira, Marcus Vinícius; Rodrigues, Tiago; de Oliveira, Regina Costa; Nunes, Luiz R.

    2010-01-01

    Xylella fastidiosa is a xylem-limited bacterium responsible for important plant diseases, like citrus-variegated chlorosis (CVC) and grapevine Pierce's disease (PD). Interestingly, in vitro growth of X. fastidiosa in chemically defined media that resemble xylem fluid has been achieved, allowing studies of metabolic processes used by xylem-dwelling bacteria to thrive in such nutrient-poor conditions. Thus, we performed microarray hybridizations to compare transcriptomes of X. fastidiosa cells grown in 3G10-R, a medium that resembles grape sap, and in Periwinkle Wilt (PW), the complex medium traditionally used to cultivate X. fastidiosa. We identified 299 transcripts modulated in response to growth in these media. Some 3G10R-overexpressed genes have been shown to be upregulated in cells directly isolated from infected plants and may be involved in plant colonization, virulence and environmental competition. In contrast, cells cultivated in PW show a metabolic switch associated with increased aerobic respiration and enhanced bacterial growth rates. PMID:20625415

  10. Seasonal Abundance and Natural Inoculativity of Insect Vectors of Xylella fastidiosa in Oklahoma Tree Nurseries and Vineyards.

    PubMed

    Overall, Lisa M; Rebek, Eric J

    2015-12-01

    Xylella fastidiosa is the causative agent of diseases of perennial plants including peach, plum, elm, oak, pecan, and grape. This bacterial pathogen is transmitted by xylem-feeding insects. In recent years, Pierce's disease of grape has been detected in 10 counties in central and northeastern Oklahoma, prompting further investigation of the disease epidemiology in this state. We surveyed vineyards and tree nurseries in Oklahoma for potential insect vectors to determine species composition, infectivity, and natural inoculativity of commonly captured insect vectors. Yellow sticky cards were used to sample insect fauna at each location. Insects were removed from sticky cards and screened for X. fastidiosa using immunocapture-PCR to determine their infectivity. A second objective was to test the natural inoculativity of insect vectors that are found in vineyards. Graphocephala versuta (Say), Graphocephala coccinea (Forster), Paraulacizes irrorata (F.), Oncometopia orbona (F.), Cuerna costalis (F.), and Entylia carinata Germar were collected from vineyards and taken back to the lab to determine their natural inoculativity. Immunocapture-PCR was used to test plant and insect samples for presence of X. fastidiosa. The three most frequently captured species from vineyards and tree nurseries were G. versuta, Clastoptera xanthocephala Germar, and O. orbona. Of those insects screened for X. fastidiosa, 2.4% tested positive for the bacterium. Field-collected G. versuta were inoculative to both ragweed and alfalfa. Following a 7-d inoculation access period, a higher percentage of alfalfa became infected than ragweed. Results from this study provide insight into the epidemiology of X. fastidiosa in Oklahoma. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Grapes

    USDA-ARS?s Scientific Manuscript database

    Grapes are grown worldwide, on about 7.9 million ha., and are used to produce wine, raisins, juice, jam, concentrate, and seed oils, as well as fresh fruit. Grapes (Vitis sp.) are members of the Vitaceae. Vitis includes two subgenera, Euvitis (38 chromosomes) and Muscadinia (40 chromosomes), with ...

  12. Grapevine genotype susceptibility to Xylella fastidiosa does not predict vector transmission success.

    PubMed

    Rashed, Arash; Daugherty, Matthew P; Almeida, Rodrigo P P

    2011-10-01

    For vector-borne diseases, interactions between vector, host, and pathogen can influence patterns of disease spread. In particular, previous studies suggest that host genotype may influence disease dynamics because of differences in susceptibility to the pathogen and, therefore, subsequent vector transmission efficiency from these plants. We tested this hypothesis by using the pathogenic bacterium Xylella fastidiosa, the etiological agent of Pierce's disease in grapevines, and its leafhopper vector Homalodisca vitripennis (Germar). Pathogen infection level and transmission efficiency among several widely cultivated red and white wine, table, and raisin grape cultivars, were compared with the expectation that vector transmission rate would differ among cultivars, because of underlying differences in susceptibility to infection. The 14 grapevine genotypes evaluated showed significant differences among cultivars in the populations of X. fastidiosa that developed in petioles. 'Flame seedless' hosted the highest bacterial populations, between 1.81 and 2.05 times higher than the least susceptible 'Merlot', 'Crimson seedless', 'Grenache Noir', and 'Rubired'. Although the transmission rate of X. fastidiosa by H. vitripennis varied substantially (zero to 33%), it was not significantly different among cultivars. These results suggest that either the relationship between vine infection level and transmission is weaker than previously reported, or innate differences in vector preference among cultivars confounded any effects of vine susceptibility to infection.

  13. Xylella fastidiosa Infection and Ethylene Exposure Result in Xylem and Water Movement Disruption in Grapevine Shoots1[OA

    PubMed Central

    Pérez-Donoso, Alonso G.; Greve, L. Carl; Walton, Jeffrey H.; Shackel, Ken A.; Labavitch, John M.

    2007-01-01

    It is conventionally thought that multiplication of the xylem-limited bacterium Xylella fastidiosa (Xf) within xylem vessels is the sole factor responsible for the blockage of water movement in grapevines (Vitis vinifera) affected by Pierce's disease. However, results from our studies have provided substantial support for the idea that vessel obstructions, and likely other aspects of the Pierce's disease syndrome, result from the grapevine's active responses to the presence of Xf, rather than to the direct action of the bacterium. The use of magnetic resonance imaging (MRI) to observe the distribution of water within the xylem has allowed us to follow nondestructively the development of vascular system obstructions subsequent to inoculation of grapevines with Xf. Because we have hypothesized a role for ethylene produced in vines following infection, the impact of vine ethylene exposure on obstruction development was also followed using MRI. In both infected and ethylene-exposed plants, MRI shows that an important proportion of the xylem vessels become progressively air embolized after the treatments. The loss of xylem water-transporting function, assessed by MRI, has been also correlated with a decrease in stem-specific hydraulic conductivity (KS) and the presence of tyloses in the lumens of obstructed water conduits. We have observed that the ethylene production of leaves from infected grapevines is greater than that from healthy vines and, therefore, propose that ethylene may be involved in a series of cellular events that coordinates the vine's response to the pathogen. PMID:17189331

  14. Characterization of novel virulent broad-host-range phages of Xylella fastidiosa and Xanthomonas.

    PubMed

    Ahern, Stephen J; Das, Mayukh; Bhowmick, Tushar Suvra; Young, Ry; Gonzalez, Carlos F

    2014-01-01

    The xylem-limited bacterium Xylella fastidiosa is the causal agent of several plant diseases, most notably Pierce's disease of grape and citrus variegated chlorosis. We report the isolation and characterization of the first virulent phages for X. fastidiosa, siphophages Sano and Salvo and podophages Prado and Paz, with a host range that includes Xanthomonas spp. Phages propagated on homologous hosts had observed adsorption rate constants of ~4 × 10(-12) ml cell(-1) min(-1) for X. fastidiosa strain Temecula 1 and ~5 × 10(-10) to 7 × 10(-10) ml cell(-1) min(-1) for Xanthomonas strain EC-12. Sano and Salvo exhibit >80% nucleotide identity to each other in aligned regions and are syntenic to phage BcepNazgul. We propose that phage BcepNazgul is the founding member of a novel phage type, to which Sano and Salvo belong. The lysis genes of the Nazgul-like phage type include a gene that encodes an outer membrane lipoprotein endolysin and also spanin gene families that provide insight into the evolution of the lysis pathway for phages of Gram-negative hosts. Prado and Paz, although exhibiting no significant DNA homology to each other, are new members of the phiKMV-like phage type, based on the position of the single-subunit RNA polymerase gene. The four phages are type IV pilus dependent for infection of both X. fastidiosa and Xanthomonas. The phages may be useful as agents for an effective and environmentally responsible strategy for the control of diseases caused by X. fastidiosa.

  15. RNA-Seq analysis of Citrus reticulata in the early stages of Xylella fastidiosa infection reveals auxin-related genes as a defense response

    PubMed Central

    2013-01-01

    Background Citrus variegated chlorosis (CVC), caused by Xylella fastidiosa, is one the most important citrus diseases, and affects all varieties of sweet orange (Citrus sinensis L. Osb). On the other hand, among the Citrus genus there are different sources of resistance against X. fastidiosa. For these species identifying these defense genes could be an important step towards obtaining sweet orange resistant varieties through breeding or genetic engineering. To assess these genes we made use of mandarin (C. reticulata Blanco) that is known to be resistant to CVC and shares agronomical characteristics with sweet orange. Thus, we investigated the gene expression in Ponkan mandarin at one day after infection with X. fastidiosa, using RNA-seq. A set of genes considered key elements in the resistance was used to confirm its regulation in mandarin compared with the susceptible sweet orange. Results Gene expression analysis of mock inoculated and infected tissues of Ponkan mandarin identified 667 transcripts repressed and 724 significantly induced in the later. Among the induced transcripts, we identified genes encoding proteins similar to Pattern Recognition Receptors. Furthermore, many genes involved in secondary metabolism, biosynthesis and cell wall modification were upregulated as well as in synthesis of abscisic acid, jasmonic acid and auxin. Conclusions This work demonstrated that the defense response to the perception of bacteria involves cell wall modification and activation of hormone pathways, which probably lead to the induction of other defense-related genes. We also hypothesized the induction of auxin-related genes indicates that resistant plants initially recognize X. fastidiosa as a necrotrophic pathogen. PMID:24090429

  16. Paradigms: examples from the bacterium Xylella fastidiosa.

    PubMed

    Purcell, Alexander

    2013-01-01

    The history of advances in research on Xylella fastidiosa provides excellent examples of how paradigms both advance and limit our scientific understanding of plant pathogens and the plant diseases they cause. I describe this from a personal perspective, having been directly involved with many persons who made paradigm-changing discoveries, beginning with the discovery that a bacterium, not a virus, causes Pierce's disease of grape and other plant diseases in numerous plant species, including important crop and forest species.

  17. Genetic Analysis of a Novel Xylella fastidiosa Subspecies Found in the Southwestern United States ▿

    PubMed Central

    Randall, Jennifer J.; Goldberg, Natalie P.; Kemp, John D.; Radionenko, Maxim; French, Jason M.; Olsen, Mary W.; Hanson, Stephen F.

    2009-01-01

    Xylella fastidiosa, the causal agent of several scorch diseases, is associated with leaf scorch symptoms in Chitalpa tashkentensis, a common ornamental landscape plant used throughout the southwestern United States. For a number of years, many chitalpa trees in southern New Mexico and Arizona exhibited leaf scorch symptoms, and the results from a regional survey show that chitalpa trees from New Mexico, Arizona, and California are frequently infected with X. fastidiosa. Phylogenetic analysis of multiple loci was used to compare the X. fastidiosa infecting chitalpa strains from New Mexico, Arizona, and trees imported into New Mexico nurseries with previously reported X. fastidiosa strains. Loci analyzed included the 16S ribosome, 16S-23S ribosomal intergenic spacer region, gyrase-B, simple sequence repeat sequences, X. fastidiosa-specific sequences, and the virulence-associated protein (VapD). This analysis indicates that the X. fastidiosa isolates associated with infected chitalpa trees in the Southwest are a highly related group that is distinct from the four previously defined taxons X. fastidiosa subsp. fastidiosa (piercei), X. fastidiosa subsp. multiplex, X. fastidiosa subsp. sandyi, and X. fastidiosa subsp. pauca. Therefore, the classification proposed for this new subspecies is X. fastidiosa subsp. tashke. PMID:19581467

  18. Grapevine rootstock effects on scion sap phenolic levels, resistance to Xylella fastidiosa infection, and progression of Pierce's disease.

    PubMed

    Wallis, Christopher M; Wallingford, Anna K; Chen, Jianchi

    2013-01-01

    The xylem-limited bacterium Xylella fastidiosa (Xf) causes Pierce's disease (PD), an important disease of grapevine, Vitis vinifera L. Grapevine rootstocks were developed to provide increased resistance to root disease, but rootstock effects on cane and vine diseases remain unclear. Grapevines that consisted of Cabernet Sauvignon or Chardonnay grafted to 13 different rootstocks were inoculated with Xf and evaluated for PD severity and Xf titer after 6 months. A subset of six rootstock/scion combinations had xylem sap phenolic levels assessed in non-infected and Xf-infected grapevines. Vigor also was analyzed by measuring root lengths and masses. Cabernet Sauvignon grafted to 101-14MG, 1103P, 420A, or Schwarzmann had reduced PD severity compared to Cabernet Sauvignon grafted to 110R, 5BB, or SO4. Chardonnay grafted to Salt Creek or Freedom had reduced PD severity compared to Chardonnay grafted to RS3 or Schwarzmann. Chardonnay grafted to RS3 had greater Xf titer than Chardonnay grafted to 101-14MG, Freedom, or Salt Creek. No other differences in Xf titer among rootstocks were observed. Of the six scion/rootstock combinations which had xylem sap phenolics analyzed, Chardonnay/RS3 had the highest levels of most phenolics whereas Cabernet Sauvignon/101-14MG had the lowest phenolic levels. However, Chardonnay/101-14MG, which had mild PD symptoms, had greater sap levels of caftaric acid than other scion/rootstock combinations. Sap levels of caftaric acid, methyl salicylate, a procyanidin trimer, and quinic acid were greater in Xf-infected vs. non-infected grapevines. Chardonnay on 101-14MG or Salt Creek had greater root mass than Chardonnay on RS3. Cabernet Sauvignon on 101-14MG had greater root mass than Cabernet Sauvignon on 110R. These results identified rootstocks with the capacity for reducing PD symptom progression. Rootstocks also were shown to affect Xf titer, xylem sap phenolic levels, and plant vigor.

  19. Grapevine rootstock effects on scion sap phenolic levels, resistance to Xylella fastidiosa infection, and progression of Pierce's disease

    PubMed Central

    Wallis, Christopher M.; Wallingford, Anna K.; Chen, Jianchi

    2013-01-01

    The xylem-limited bacterium Xylella fastidiosa (Xf) causes Pierce's disease (PD), an important disease of grapevine, Vitis vinifera L. Grapevine rootstocks were developed to provide increased resistance to root disease, but rootstock effects on cane and vine diseases remain unclear. Grapevines that consisted of Cabernet Sauvignon or Chardonnay grafted to 13 different rootstocks were inoculated with Xf and evaluated for PD severity and Xf titer after 6 months. A subset of six rootstock/scion combinations had xylem sap phenolic levels assessed in non-infected and Xf-infected grapevines. Vigor also was analyzed by measuring root lengths and masses. Cabernet Sauvignon grafted to 101-14MG, 1103P, 420A, or Schwarzmann had reduced PD severity compared to Cabernet Sauvignon grafted to 110R, 5BB, or SO4. Chardonnay grafted to Salt Creek or Freedom had reduced PD severity compared to Chardonnay grafted to RS3 or Schwarzmann. Chardonnay grafted to RS3 had greater Xf titer than Chardonnay grafted to 101-14MG, Freedom, or Salt Creek. No other differences in Xf titer among rootstocks were observed. Of the six scion/rootstock combinations which had xylem sap phenolics analyzed, Chardonnay/RS3 had the highest levels of most phenolics whereas Cabernet Sauvignon/101-14MG had the lowest phenolic levels. However, Chardonnay/101-14MG, which had mild PD symptoms, had greater sap levels of caftaric acid than other scion/rootstock combinations. Sap levels of caftaric acid, methyl salicylate, a procyanidin trimer, and quinic acid were greater in Xf-infected vs. non-infected grapevines. Chardonnay on 101-14MG or Salt Creek had greater root mass than Chardonnay on RS3. Cabernet Sauvignon on 101-14MG had greater root mass than Cabernet Sauvignon on 110R. These results identified rootstocks with the capacity for reducing PD symptom progression. Rootstocks also were shown to affect Xf titer, xylem sap phenolic levels, and plant vigor. PMID:24376452

  20. Post-harvest proteomics of grapes infected by Penicillium during withering to produce Amarone wine.

    PubMed

    Lorenzini, Marilinda; Mainente, Federica; Zapparoli, Giacomo; Cecconi, Daniela; Simonato, Barbara

    2016-05-15

    The study of withered grape infection by Penicillium, a potentially toxigenic fungus, is relevant to preserve grape quality during the post-harvest dehydration process. This report describes the first proteomic analysis of Amarone wine grapes, infected by two strains of Penicillium expansum (Pe1) and Penicillium crustosum (Pc4). Protein identification by MS analysis allowed a better understanding of physiological mechanisms underlying the pathogen attack. The Pe1 strain had a major impact on Vitis vinifera protein expression inducing pathogenesis-related proteins and other protein species involved in energy metabolism. A greater expression of new Penicillium proteins involved in energy metabolism and some protein species related to redox homeostasis has been observed on grapes infected by Pc4 strain. Moreover, the new induced proteins in infected grapes could represent potential markers in withered grapes, thus creating the chance to develop case-sensitive prevention strategies to inhibit fungal growth.

  1. Discrimination of fungal infections on grape berries via spectral signatures

    NASA Astrophysics Data System (ADS)

    Molitor, Daniel; Griesser, Michaela; Schütz, Erich; Khuen, Marie-Therese; Schefbeck, Christa; Ronellenfitsch, Franz Kai; Schlerf, Martin; Beyer, Marco; Schoedl-Hummel, Katharina; Anhalt, Ulrike; Forneck, Astrid

    2016-04-01

    The fungal pathogens Botrytis cinerea and Penicillium expansum are causing economic damages on grapevine worldwide. Especially the simultaneous occurrence of both often results in off-flavours highly threatening wine quality. For the classification of grape quality as well as for the determination of targeted enological treatments, the knowledge of the level of fungal attack is of highest interest. However, visual assessment and pathogen discrimination are cost-intensive. Consequently, a pilot laboratory study aimed at (i) detecting differences in spectral signatures between grape berry lots with different levels of infected berries (B. cinerea and/or P. expansum) and (ii) detecting links between spectral signatures and biochemical as well as quantitative molecular markers for fungal attack. To this end, defined percentages (infection levels) of table grape berries were inoculated with fungal spore suspensions. Spectral measurements were taken using a FieldSpec 3 Max spectroradiometer (ASD Inc., Boulder/Colorado, USA) in regular intervals after inoculation. In addition, fungal attack was determined enzymatically) and quantitatively (real-time PCR). In addition, gluconic acid concentrations (as a potential markers for fungal attack) were determined photometrically. Results indicate that based on spectral signatures, a discrimination of P. expansum and B. cinerea infections as well as of different B. cinerea infection levels is possible. Real-time PCR analyses, detecting DNA levels of both fungi, showed yet a low detection level. Whereas the gluconic acid concentrations turned out to be specific for the two fungi tested (B. cinerea vs. P. expansum) and thus may serve as a differentiating biochemical marker. Correlation analyses between spectral measurements and biological data (gluconic acid concentrations, fungi DNA) as well as further common field and laboratory trials are targeted.

  2. Development of single chain variable fragment (scFv) antibodies against Xylella fastidiosa subsp. pauca by phage display

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a member of the gamma proteobacteria. It is fastidious, insect-vectored and xylem-limited and causes a variety of diseases, some severe, on a wide range of economically important perennial crops, including grape and citrus. Xylella fastidiosa subsp pauca causes citrus variegat...

  3. Genomic characterization of a lysogenic phage from Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is an important pathogen causing disease of several economically important crops such as grape and almond in Central California. Despite intensive efforts to study this nutritionally fastidious pathogen, many biological traits of the bacterium such as bacteriophages remains poorl...

  4. Effects of kaolin particle film and imidacloprid on glassy-winged sharpshooter (Homalodisca vitripennis) (Hemiptera: Cicadellidae)populations and the prevention of spread of Xylella fastidiosa in grape

    USDA-ARS?s Scientific Manuscript database

    The glassy-winged sharpshooter (GWSS), Homalodisca coagulata (Say), was introduced into California and soon became a major pest of important agronomic, horticultural, landscape, ornamental crops and native trees in California. This pest feeds readily on grape and, in doing so, transmits X. fastidio...

  5. Infectivity and transmission of Xylella fastidiosa Salento strain by Philaenus spumarius L. (Hemiptera: Aphrophoridae) in Apulia, Italy

    USDA-ARS?s Scientific Manuscript database

    Discovery of X. fastidiosa from olive trees with “Olive quick decline syndrome" (OQDS) in October 2013 on the western coast of the Salento Peninsula prompted an immediate search for insect vectors of the bacterium. The dominant xylem-fluid feeding hemipteran collected in olive orchards was the meado...

  6. Grapevine rootstock effects on scion sap phenolic levels, resistance to Xylella fastidiosa infection, and progression of Pierce’s disease

    USDA-ARS?s Scientific Manuscript database

    The xylem-limited bacterium Xylella fastidiosa (Xf) causes Pierce’s disease (PD), an important disease of grapevine, Vitis vinifera L. Grapevine rootstocks were developed to provide increased resistance to root disease, but rootstock effects on cane and vine diseases remain unclear. Grapevines that ...

  7. Conjugative Plasmid Transfer in Xylella fastidiosa Is Dependent on tra and trb Operon Functions

    PubMed Central

    Van Horn, Christopher R.

    2017-01-01

    ABSTRACT The insect-transmitted plant pathogen Xylella fastidiosa is capable of efficient horizontal gene transfer (HGT) and recombination. Natural transformation occurs at high rates in X. fastidiosa, but there also is evidence that certain strains of X. fastidiosa carry native plasmids equipped with transfer and mobilization genes, suggesting conjugation as an additional mechanism of HGT in some instances. Two operons, tra and trb, putatively encoding a conjugative type IV secretion system, are found in some but not all X. fastidiosa isolates, often on native plasmids. X. fastidiosa strains that carry the conjugative transfer genes can belong to different subspecies and frequently differ in host ranges. Using X. fastidiosa strain M23 (X. fastidiosa subsp. fastidiosa) or Dixon (X. fastidiosa subsp. multiplex) as the donor strain and Temecula (X. fastidiosa subsp. fastidiosa) as the recipient strain, plasmid transfer was characterized using the mobilizable broad-host-range vector pBBR5pemIK. Transfer of plasmid pBBR5pemIK was observed under in vitro conditions with both donor strains and was dependent on both tra and trb operon functions. A conjugative mechanism likely contributes to gene transfer between diverse strains of X. fastidiosa, possibly facilitating adaptation to new environments or different hosts. IMPORTANCE Xylella fastidiosa is an important plant pathogen worldwide, infecting a wide range of different plant species. The emergence of new diseases caused by X. fastidiosa, or host switching of existing strains, is thought to be primarily due to the high frequency of HGT and recombination in this pathogen. Transfer of plasmids by a conjugative mechanism enables movement of larger amounts of genetic material at one time, compared with other routes of gene transfer such as natural transformation. Establishing the prevalence and functionality of this mechanism in X. fastidiosa contributes to a better understanding of HGT, adaptation, and disease emergence

  8. Detection and Diversity Assessment of Xylella fastidiosa in Field-Collected Plant and Insect Samples by Using 16S rRNA and gyrB Sequences

    PubMed Central

    Rodrigues, Jorge L. M.; Silva-Stenico, M. E.; Gomes, J. E.; Lopes, J. R. S.; Tsai, S. M.

    2003-01-01

    The causal agent of diseases in many economically important plants is attributed to the xylem-limited bacterium Xylella fastidiosa. The detection of this plant pathogen has been hampered due to its difficult isolation and slow growth on plates. Nearly complete nucleotide sequences of the 16S rRNA gene and partial sequences of the gyrB gene were determined for 18 strains of X. fastidiosa isolated from different plant hosts. A phylogenetic analysis, based on gyrB, grouped strains in three clusters; grape-isolated strains formed one cluster, citrus-coffee strains formed another cluster, and a third cluster resulted from all other strains. Primer pairs designed for the 16S rRNA and gyrB genes were extensively searched in databases to verify their in silico specificity. Primer pairs were certified with 30 target and 36 nontarget pure cultures of microorganisms, confirming 100% specificity. A multiplex PCR protocol was developed and its sensitivity tested. Sequencing of PCR products confirmed the validity of the multiplex PCR. Xylella fastidiosa was detected in field-collected plants, disease vector insects, and nonsymptomatic but infected plants. Specific detection of X. fastidiosa may facilitate the understanding of its ecological significance and prevention of spread of the disease. PMID:12839807

  9. Diagnosis of Pierce's disease using biomarkers specific to Xylella fastidiosa rRNA and Vitis vinifera gene expression.

    PubMed

    Choi, H-K; Goes da Silva, F; Lim, H-J; Iandolino, A; Seo, Y-S; Lee, S-W; Cook, D R

    2010-10-01

    Pierce's disease (PD), caused by Xylella fastidiosa, represents one of the most damaging diseases of cultivated grape. Management of PD in the vineyard often relies on the removal of infected individuals, which otherwise serve as a source of inoculum for nearby healthy vines. Effective implementation of such control measures requires early diagnosis, which is complicated by the fact that infected vines often harbor high titers of the pathogen in advance of visual symptom development. Here, we report a biomarker system that simultaneously monitors Xylella-induced plant transcripts as well as Xylella ribosomal (r)RNA. Plant biomarker genes were derived from a combination of in silico analysis of grape expressed sequence tags and validation by means of reverse-transcriptase polymerase chain reaction (RT-PCR). Four genes upregulated upon PD infection were individually multiplexed with an X. fastidiosa marker rRNA and scored using either real-time RT-PCR or gel-based conventional RT-PCR techniques. The system was sufficiently sensitive to detect both host gene transcript and pathogen rRNA in asymptomatic infected plants. Moreover, these plant biomarker genes were not induced by water deficit, which is a component of PD development. Such biomarker genes could have utility for disease control by aiding early detection and as a screening tool in breeding programs.

  10. Yeast populations residing on healthy or botrytis-infected grapes from a vineyard in Attica, Greece.

    PubMed

    Nisiotou, Aspasia A; Nychas, George-John E

    2007-04-01

    The yeast flora associated with healthy and Botrytis-infected grapes was assessed. Molecular identification methods assigned isolates to six genera and nine species. For the first time Hanseniaspora opuntiae was encountered as an inhabitant of the grape ecosystem. By using DraI, an informative restriction fragment length polymorphism pattern was generated to distinguish H. opuntiae from the closely related organism Hanseniaspora guilliermondii. Botrytis infection resulted in a larger population and greater diversity of yeasts enriched with fermentative or spoilage species.

  11. Antibacterial activity of phenolic compounds against the phytopathogen Xylella fastidiosa.

    PubMed

    Maddox, Christina E; Laur, Lisa M; Tian, Li

    2010-01-01

    Xylella fastidiosa is a pathogenic bacterium that causes diseases in many crop species, which leads to considerable economic loss. Phenolic compounds (a group of secondary metabolites) are widely distributed in plants and have shown to possess antimicrobial properties. The anti-Xylella activity of 12 phenolic compounds, representing phenolic acid, coumarin, stilbene and flavonoid, was evaluated using an in vitro agar dilution assay. Overall, these phenolic compounds were effective in inhibiting X. fastidiosa growth, as indicated by low minimum inhibitory concentrations (MICs). In addition, phenolic compounds with different structural features exhibited different anti-Xylella capacities. Particularly, catechol, caffeic acid and resveratrol showed strong anti-Xylella activities. Differential response to phenolic compounds was observed among X. fastidiosa strains isolated from grape and almond. Elucidation of secondary metabolite-based host resistance to X. fastidiosa will have broad implication in combating X. fastidiosa-caused plant diseases. It will facilitate future production of plants with improved disease resistance properties through genetic engineering or traditional breeding approaches and will significantly improve crop yield.

  12. Combined use of a new SNP-based assay and multilocus SSR markers to assess genetic diversity of Xylella fastidiosa subsp. pauca infecting citrus and coffee plants.

    PubMed

    Montes-Borrego, Miguel; Lopes, Joao R S; Jiménez-Díaz, Rafael M; Landa, Blanca B

    2015-03-01

    Two haplotypes of Xylella fastidiosa subsp. pauca (Xfp) that correlated with their host of origin were identified in a collection of 90 isolates infecting citrus and coffee plants in Brazil, based on a single-nucleotide polymorphism in the gyrB sequence. A new single-nucleotide primer extension (SNuPE) protocol was designed for rapid identification of Xfp according to the host source. The protocol proved to be robust for the prediction of the Xfp host source in blind tests using DNA from cultures of the bacterium, infected plants, and insect vectors allowed to feed on Xfp-infected citrus plants. AMOVA and STRUCTURE analyses of microsatellite data separated most Xfp populations on the basis of their host source, indicating that they were genetically distinct. The combined use of the SNaPshot protocol and three previously developed multilocus SSR markers showed that two haplotypes and distinct isolates of Xfp infect citrus and coffee in Brazil and that multiple, genetically different isolates can be present in a single orchard or infect a single tree. This combined approach will be very useful in studies of the epidemiology of Xfp-induced diseases, host specificity of bacterial genotypes, the occurrence of Xfp host jumping, vector feeding habits, etc., in economically important cultivated plants or weed host reservoirs of Xfp in Brazil and elsewhere.

  13. Phylogenetic Relationships of Xylella fastidiosa Strains Isolated from Landscape Ornamentals in Southern California.

    PubMed

    Hernandez-Martinez, Rufina; de la Cerda, Karla A; Costa, Heather S; Cooksey, Donald A; Wong, Francis P

    2007-07-01

    ABSTRACT Xylella fastidiosa is an insect-borne, xylem-limited pathogenic bacterium that has been associated with a rise in incidence of diseased landscape ornamentals in southern California. The objective of this study was to genetically characterize strains isolated from ornamental hosts to understand their distribution and identity. Strains of X. fastidiosa isolated from ornamentals were characterized using a multiprimer polymerase chain reaction (PCR) system, random amplified polymorphic DNA (RAPD)-PCR, and sequence analysis of the 16S-23S rDNA intergenic spacer region (ISR). Based on RAPD-PCR and 16S-23S rDNA ISR, strains isolated from daylily, jacaranda, and magnolia clustered with members of X. fastidiosa subsp. sandyi and caused oleander leaf scorch but not Pierce's disease symptoms in glasshouse assays on oleander and grape, respectively. This demonstrated both that our groupings based on genetic characterization were valid and that strains of X. fastidiosa subsp. sandyi are present in hosts other than oleander. Strains isolated from Spanish broom, cherry, and one strain isolated from western redbud clustered with X. fastidiosa subsp. fastidiosa members. Strains isolated from purple-leafed plum, olive, peach, plum, sweetgum, maidenhair tree, crape myrtle, and another western redbud strain clustered with members of X. fastidiosa subsp. multiplex. All strains isolated from mulberry and one from heavenly bamboo formed a separate cluster that has not yet been defined as a subspecies.

  14. Conjugative plasmid transfer in Xylella fastidiosa is dependent on tra and trb operon functions.

    PubMed

    Burbank, Lindsey P; Van Horn, Christopher R

    2017-08-14

    The insect-transmitted plant pathogen Xylella fastidiosa is capable of efficient horizontal gene transfer (HGT) and recombination. Natural transformation occurs at high rates in X. fastidiosa, but there also is evidence that certain strains of X. fastidiosa carry native plasmids equipped with transfer and mobilization genes, suggesting conjugation as an additional mechanism of HGT in some instances. Two operons, tra and trb, putatively encoding a conjugative Type IV secretion system are found in some but not all X. fastidiosa isolates, often on native plasmids. X. fastidiosa strains that carry the conjugative transfer genes can belong to different subspecies, and frequently differ in host ranges. Using X. fastidiosa strains M23 (subspecies fastidiosa) or Dixon (subspecies multiplex) as the donor strain and Temecula (subspecies fastidiosa) as the recipient strain, plasmid transfer was characterized using the mobilizable broad host range vector pBBR5pemIK. Transfer of plasmid pBBR5pemIK was observed under in vitro conditions with both donor strains, and was dependent on both tra and trb operon functions. A conjugative mechanism likely contributes to gene transfer between diverse strains of X. fastidiosa, possibly facilitating adaptation to new environments or different hosts.IMPORTANCEXylella fastidiosa is an important plant pathogen world-wide, infecting a wide range of different plant species. Emergence of new diseases caused by X. fastidiosa, or host-switching of existing strains is thought to be primarily due to the high frequency of HGT and recombination in this pathogen. Transfer of plasmids by a conjugative mechanism enables movement of larger amounts of genetic material at one time compared with other routes of gene transfer such as natural transformation. Establishing the prevalence and functionality of this mechanism in X. fastidiosa contributes to a better understanding of HGT and adaptation, and disease emergence in this diverse pathogen. This is a work

  15. Transcriptional Regulation of the Grape Cytochrome P450 Monooxygenase Gene CYP736B Expression in Response to Xylella fastidiosa Infection

    USDA-ARS?s Scientific Manuscript database

    Plant cytochrome P450 monooxygenases are a group of versatile redox proteins that mediate the biosynthesis of lignins, terpenes, alkaloids, and a variety of other secondary compounds which act as plant defense agents. To determine if cytochrome P450 monooxygenases are involved in defense response to...

  16. Probe-based real-time PCR method for multilocus melt typing of Xylella fastidiosa strains.

    PubMed

    Brady, Jeff A; Faske, Jennifer B; Ator, Rebecca A; Castañeda-Gill, Jessica M; Mitchell, Forrest L

    2012-04-01

    Epidemiological studies of Pierce's disease (PD) can be confounded by a lack of taxonomic detail on the bacterial causative agent, Xylella fastidiosa (Xf). PD in grape is caused by strains of Xylella fastidiosa subsp. fastidiosa, but is not caused by other subspecies of Xf that typically colonize plants other than grape. Detection assays using ELISA and qPCR are effective at detecting and quantifying Xf presence or absence, but offer no information on Xf subspecies or strain identity. Surveying insects or host plants for Xf by current ELISA or qPCR methods provides only presence/absence and quantity information for any and all Xf subspecies, potentially leading to false assessments of disease threat. This study uses a series of adjacent-hybridizing DNA melt analysis probes that are capable of efficiently discriminating Xf subspecies and strain relationships in rapid real-time PCR reactions.

  17. Bacterial species associated with sound and Botrytis-infected grapes from a Greek vineyard.

    PubMed

    Nisiotou, Aspasia A; Rantsiou, Kalliopi; Iliopoulos, Vassilios; Cocolin, Luca; Nychas, George-John E

    2011-02-28

    Grape bacterial microbiota plays central roles in the quality of grapes and wine, yet its diversity remains poorly described. In the present study, bacterial species associated with sound and Botrytis-infected grapes of two cultivars originating from the same vineyard were assessed. Isolates were identified by PCR-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) and sequence analysis of partial 16S rRNA gene. Comparable counts were recorded between Botrytis-infected and sound grape samples. In all cases, the majority of isolates belonged to different species of Enterobacteriaceae. The dominant species in the vineyard was Klebsiella oxytoca that was found in different combinations with Citrobacter freundii, Enterobacter spp., Erwinia sp., Pantoea dispersa, Tatumella ptyseos or other species. In fermenting musts, those populations declined while other species evolved, like Lactobacillus plantarum and Enterobacter ludwigii. Populations in botrytised samples persisted longer during spontaneous fermentations. Present study suggests that bacterial diversity on grapes may be wider than previously described. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Genetic Differences between Two Strains of Xylella fastidiosa Revealed by Suppression Subtractive Hybridization†

    PubMed Central

    Harakava, Ricardo; Gabriel, Dean W.

    2003-01-01

    Suppression subtractive hybridization was used to rapidly identify 18 gene differences between a citrus variegated chlorosis (CVC) strain and a Pierce's disease of grape (PD) strain of Xylella fastidiosa. The results were validated as being highly representative of actual differences by comparison of the completely sequenced genome of a CVC strain with that of a PD strain. PMID:12571065

  19. Characterization of Xylella fastidiosa popP gene required for pathogenicity

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf) possesses a two component regulatory system (TCS) popP-popQ which differentially regulates genes in response to environmental stimuli. To elucidate the role of popP in Pierce’s disease (PD) of grapes, a site-directed deletion method and chromosome-based genetic complementatio...

  20. Arabidopsis Thaliana Ecotypes With Differential Susceptibility To The Bacterial Pathogen Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Pierce’s disease of grapes and almond leaf scorch are devastating diseases caused by the bacterium Xylella fastidiosa (Xf). To date, progress in determining the mechanisms of host plant susceptibility, tolerance or resistance has been slow, due in large part to the long generation time and limited a...

  1. Environmental factors affecting twitching motility, biofilm development, and aggregation by Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    The bacterial pathogen Xylella fastidiosa causes many important plant diseases in different crops such as citrus, grapes, almond and coffee. While disease symptoms expressed by this pathogen are not completely understood, it is widely accepted that blockage of xylem vessels by aggregates of the bact...

  2. Evaluation of Arabidopsis thaliana as a model host for Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Pierce’s disease of grapes and almond leaf scorch are diseases caused by the bacterium Xylella fastidiosa. To date, progress determining mechanisms of host plant susceptibility, tolerance or resistance has been slow, due in large part to the long generation time and limited available genetic resourc...

  3. Evaluation of Arabidopsis thaliana as an experimental host for Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Pierce’s disease of grapes and almond leaf scorch are diseases caused by the bacterium Xylella fastidiosa. To date, progress determining mechanisms of host plant susceptibility, tolerance or resistance has been slow, due in large part to the long generation time and limited available genetic resourc...

  4. Quantification and localization of hesperidin and rutin in Citrus sinensis grafted on C. limonia after Xylella fastidiosa infection by HPLC-UV and MALDI imaging mass spectrometry.

    PubMed

    Soares, Márcio Santos; da Silva, Danielle Fernandes; Forim, Moacir Rossi; da Silva, Maria Fátima das Graças Fernandes; Fernandes, João Batista; Vieira, Paulo Cezar; Silva, Denise Brentan; Lopes, Norberto Peporine; de Carvalho, Sérgio Alves; de Souza, Alessandra Alves; Machado, Marcos Antônio

    2015-07-01

    A high performance liquid chromatography-ultraviolet (HPLC-UV) method was developed for quantifying hesperidin and rutin levels in leaves and stems of Citrus limonia, with a good linearity over a range of 1.0-80.0 and 1.0-50.0 μg mL(-1) respectively, with r(2)>0.999 for all curves. The limits of detection (LOD) for both flavonoids were 0.6 and 0.5 μg mL(-1), respectively, with quantification (LOQ) being 2.0 and 1.0 μg mL(-1), respectively. The quantification method was applied to Citrus sinensis grafted onto C. limonia with and without CVC (citrus variegated chlorosis) symptoms after Xylella fastidiosa infection. The total content of rutin was low and practically constant in all analyses in comparison with hesperidin, which showed a significant increase in its amount in symptomatic leaves. Scanning electron microscopy studies on leaves with CVC symptoms showed vessel occlusion by biofilm, and a crystallized material was noted. Considering the difficulty in isolating these crystals for analysis, tissue sections were analyzed by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) to confirm the presence of hesperidin at the site of infection. The images constructed from MS/MS data with a specific diagnostic fragment ion (m/z 483) also showed higher ion intensities for it in infected plants than in healthy ones, mainly in the vessel regions. These data suggest that hesperidin plays a role in the plant-pathogen interaction, probably as a phytoanticipin. This method was also applied to C. sinensis and C. limonia seedlings, and comparison with the graft results showed that the rootstock had an increased hesperidin content ∼3.6 fold greater in the graft stem than in the stem of C. sinensis seedlings. Increase in hesperidin content by rootstock can be related to induced internal defense mechanisms.

  5. Network analysis reveals why Xylella fastidiosa will persist in Europe.

    PubMed

    Strona, Giovanni; Carstens, Corrie Jacobien; Beck, Pieter S A

    2017-12-01

    The insect vector borne bacterium Xylella fastidiosa was first detected in olive trees in Southern Italy in 2013, and identified as the main culprit behind the 'olive quick decline syndrome'. Since then, the disease has spread rapidly through Italy's main olive oil producing region. The epidemiology of the outbreak is largely unstudied, with the list of X. fastidiosa hosts and vectors in Europe likely incomplete, and the role humans play in dispersal unknown. These knowledge gaps have led to management strategies based on general assumptions that require, among others, local vector control and, in certain areas, the destruction of infected plants and healthy ones around them in an attempt to eradicate or halt the spreading pest. Here we show that, regardless of epidemiological uncertainties, the mere distribution of olive orchards in Southern Italy makes the chances of eradicating X. fastidiosa from the region extremely slim. Our results imply that Southern Italy is becoming a reservoir for X. fastidiosa. As a consequence, management strategies should keep the prevalence of X. fastidiosa in the region as low as possible, primarily through vector control, lest the pathogen, that has also been detected in southern France and the island of Mallorca (Spain), continues spreading through Italy and Europe.

  6. Contribution of rpfB to cell-to-cell signal synthesis, virulence, and vector transmission of Xylella fastidiosa.

    PubMed

    Almeida, Rodrigo P P; Killiny, Nabil; Newman, Karyn L; Chatterjee, Subhadeep; Ionescu, Michael; Lindow, Steven E

    2012-04-01

    In Xylella fastidiosa the fatty acid signal molecule diffusible signaling factor (DSF) is produced and sensed by components of the regulation of pathogenicity factors (rpf) cluster; lack of DSF production in RpfF mutants results in a non-vector-transmissible phenotype yet cells are hypervirulent to grape. rpfB has not been characterized in Xylella fastidiosa, although its homolog has been suggested to be required for DSF synthesis in Xanthomonas campestris pv. campestris. We show that RpfB is involved in DSF processing in both Xylella fastidiosa and Xanthomonas campestris, affecting the profile of DSF-like fatty acids observed in thin-layer chromatography. Although three fatty acids whose production is dependent on RpfF were detected in Xylella fastidiosa and Xanthomonas campestris wild-type strains, their respective rpfB mutants accumulated primarily one chemical species. Although no quantifiable effect of rpfB on plant colonization by Xylella fastidiosa was found, insect colonization and transmission was reduced. Thus, RpfB apparently is involved in DSF processing, and like Xanthomonas campestris, Xylella fastidiosa also produces multiple DSF molecules. It is possible that Xylella fastidiosa coordinates host vector and plant colonization by varying the proportions of different forms of DSF signals via RpfB.

  7. Comparative Genomics- Identifying similarities and differences across three leafhopper vectors of Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Leafhoppers are the second most important vectors of agricultural diseases, thus we examined the gene expression across three leafhopper leafhoppers, Homalodisca vitripennis, Graphocephala atropunctata, and Oncometopia nigricans, which are vectors of the plant-infecting bacterium, Xylella fastidiosa...

  8. Beta 1, 4-glucanase in Glassy-Winged Sharpshooter Saliva, and its Possible Role in Infection and Movement of X. fastidiosa

    USDA-ARS?s Scientific Manuscript database

    The purpose of this project is to determine whether 1, 4-glucanase (EGase), the major enzymatic protein in watery saliva of glassy-winged sharpshooter (GWSS) co-localizes via immunocytochemistry with the few ‘pioneer’ Xylella fastidiosa (Xf) cells that are inoculated into a plant by this vector. If...

  9. Plasmids of Xylella fastidiosa Mulberry-Infecting Strains Share Extensive Sequence Identity and Gene Complement with pVEIS01 From the Earthworm Symbiont Verminephrobacter Eiseniae

    USDA-ARS?s Scientific Manuscript database

    A ~25 kbp plasmid was present in each of four Californian strains of Xylella fastidiosa from mulberry affected with leaf scorch disease. Fragments of each plasmid were cloned into E. coli, sequenced, and assembled into circular contigs of 25,105 bp (pXF-RIV11 and pXF-RIV16) or 24,372 bp (pXF-RIV19 a...

  10. The Xylella fastidiosa Biocontrol Strain EB92-1 Genome Is Very Similar and Syntenic to Pierce's Disease Strains

    PubMed Central

    Zhang, Shujian; Flores-Cruz, Zomary; Kumar, Dibyendu; Chakrabarty, Pranjib; Hopkins, Donald L.; Gabriel, Dean W.

    2011-01-01

    Xylella fastidiosa infects a wide range of plant hosts and causes economically serious diseases, including Pierce's disease (PD) of grapevines. X. fastidiosa biocontrol strain EB92-1 is infectious to grapevines but does not cause symptoms. The draft genome of EB92-1 reveals that it may be missing 10 potential pathogenicity effectors. PMID:21914886

  11. The Xylella fastidiosa biocontrol strain EB92-1 genome is very similar and syntenic to Pierce's disease strains.

    PubMed

    Zhang, Shujian; Flores-Cruz, Zomary; Kumar, Dibyendu; Chakrabarty, Pranjib; Hopkins, Donald L; Gabriel, Dean W

    2011-10-01

    Xylella fastidiosa infects a wide range of plant hosts and causes economically serious diseases, including Pierce's disease (PD) of grapevines. X. fastidiosa biocontrol strain EB92-1 is infectious to grapevines but does not cause symptoms. The draft genome of EB92-1 reveals that it may be missing 10 potential pathogenicity effectors.

  12. Diffusible signal factor-repressed extracellular traits enable attachment of Xylella fastidiosa to insect vectors and transmission.

    PubMed

    Baccari, Clelia; Killiny, Nabil; Ionescu, Michael; Almeida, Rodrigo P P; Lindow, Steven E

    2014-01-01

    The hypothesis that a wild-type strain of Xylella fastidiosa would restore the ability of rpfF mutants blocked in diffusible signal factor production to be transmitted to new grape plants by the sharpshooter vector Graphocephala atropunctata was tested. While the rpfF mutant was very poorly transmitted by vectors irrespective of whether they had also fed on plants infected with the wild-type strain, wild-type strains were not efficiently transmitted if vectors had fed on plants infected with the rpfF mutant. About 100-fewer cells of a wild-type strain attached to wings of a vector when suspended in xylem sap from plants infected with an rpfF mutant than in sap from uninfected grapes. The frequency of transmission of cells suspended in sap from plants that were infected by the rpfF mutant was also reduced over threefold. Wild-type cells suspended in a culture supernatant of an rpfF mutant also exhibited 10-fold less adherence to wings than when suspended in uninoculated culture media. A factor released into the xylem by rpfF mutants, and to a lesser extent by the wild-type strain, thus inhibits their attachment to, and thus transmission by, sharpshooter vectors and may also enable them to move more readily through host plants.

  13. Role of cold shock proteins in Xylella fastidiosa virulence

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf), causal agent of Pierce’s Disease (PD) of grapevine, is mainly prevalent in warmer climates. Subjecting Xf-infected grapevines to cold temperatures can, in many cases, effectively eliminate the bacterial population, a phenomenon known as cold curing. However, very little is k...

  14. The importance of cold shock proteins in Xylella fastidiosa virulence

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf), causal agent of Pierce’s Disease (PD) of grapevine, is mainly prevalent in warmer climates. Subjecting Xf-infected grapevines to cold temperatures can, in many cases, effectively eliminate the bacterial population, a phenomenon known as cold curing. However, very little is k...

  15. Seasonal population dynamics of Draeculacephala minerva (Hemiptera: Cicadellidae) and transmission of Xylella fastidiosa.

    PubMed

    Cabrera-La Rosa, Juan C; Johnson, Marshall W; Civerolo, Edwin L; Chen, Jianchi; Groves, Russell L

    2008-08-01

    The grass sharpshooter, Draeculacephala minerva Ball (Hemiptera: Cicadellidae), is a very common and often abundant grass-feeding leafhopper in California. Its population dynamics and ability to transmit Xylella fastidiosa were monitored over a 2-yr period in California's San Joaquin Valley. Collections of individuals from natural populations in irrigated pastures and alfalfa, Medicago savita L. fields adjacent to X. fastidiosa-infected almond (Prunus spp.) orchards indicated the occurrence of three discrete generations per year that peaked during the summer. Population densities varied significantly among experimental field survey sites. Insects captured on intercepting mesh traps, yellow sticky cards, and UV-light traps indicated local movement of these insects into and surrounding X. fastidiosa-infected, almond orchards. Local movement and seasonal transmission of X. fastidiosa from infected almonds to Catharanthus roseus (L.) G. Don indicated that this insect may be partly responsible for the slow spread of almond leaf scorch now recently observed in California's San Joaquin Valley.

  16. The DinJ/RelE toxin-antitoxin system suppresses bacterial proliferation and virulence of Xylella fastidiosa in grapevine

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa, the causal agent of Pierce’s disease of grapes, is a slow-growing, xylem-limited, bacterial pathogen. Disease progression is characterized by systemic spread of the bacterium through xylem vessel networks, causing leaf scorching symptoms, senescence, and vine decline. It appears ...

  17. Two whole genome sequences of Xylella fastidiosa (strains M12 and M23) causing almond leaf scorch disease in California

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a Gram negative, nutritionally fastidious plant pathogenic bacterium that causes many economically important diseases including almond leaf scorch disease (ALSD) and Pierce’s disease of grape in California, as well as citrus variegated chlorosis in South America. Genome inform...

  18. Characterization of regulatory pathways in Xylella fastidiosa: genes and phenotypes controlled by gacA.

    PubMed

    Shi, Xiang Yang; Dumenyo, C Korsi; Hernandez-Martinez, Rufina; Azad, Hamid; Cooksey, Donald A

    2009-04-01

    The xylem-limited, insect-transmitted bacterium Xylella fastidiosa causes Pierce's disease in grapes through cell aggregation and vascular clogging. GacA controls various physiological processes and pathogenicity factors in many gram-negative bacteria, including biofilm formation in Pseudomonas syringae pv. tomato DC3000. Cloned gacA of X. fastidiosa was found to restore the hypersensitive response and pathogenicity in gacA mutants of P. syringae pv. tomato DC3000 and Erwinia amylovora. A gacA mutant of X. fastidiosa (DAC1984) had significantly reduced abilities to adhere to a glass surface, form biofilm, and incite disease symptoms on grapevines, compared with the parent (A05). cDNA microarray analysis identified 7 genes that were positively regulated by GacA, including xadA and hsf, predicted to encode outer membrane adhesion proteins, and 20 negatively regulated genes, including gumC and an antibacterial polypeptide toxin gene, cvaC. These results suggest that GacA of X. fastidiosa regulates many factors, which contribute to attachment and biofilm formation, as well as some physiological processes that may enhance the adaptation and tolerance of X. fastidiosa to environmental stresses and the competition within the host xylem.

  19. Water deficit modulates the response of Vitis vinifera to the Pierce's disease pathogen Xylella fastidiosa.

    PubMed

    Choi, Hong-Kyu; Iandolino, Alberto; da Silva, Francisco Goes; Cook, Douglas R

    2013-06-01

    Pierce's disease, caused by the bacterium Xylella fastidiosa, is one of the most devastating diseases of cultivated grape, currently restricted to the Americas. To test the long-standing hypothesis that Pierce's disease results from pathogen-induced drought stress, we used the Affymetrix Vitis GeneChip to compare the transcriptional response of Vitis vinifera to Xylella infection, water deficit, or a combination of the two stresses. The results reveal a redirection of gene transcription involving 822 genes with a minimum twofold change (P < 0.05), including the upregulation of transcripts for phenylpropanoid and flavonoid biosynthesis, pathogenesis-related proteins, abscisic acid- and jasmonic acid-responsive biosynthesis, and downregulation of transcripts related to photosynthesis, growth, and nutrition. Although the transcriptional response of plants to Xylella infection was largely distinct from the response of healthy plants to water stress, we find that 138 of the pathogen-induced genes exhibited a significantly stronger transcriptional response when plants were simultaneously exposed to infection and drought stress, suggesting a strong interaction between disease and water deficit. This interaction between drought stress and disease was mirrored in planta at the physiological level for aspects of water relations and photosynthesis and in terms of the severity of disease symptoms and the extent of pathogen colonization, providing a molecular correlate of the classical concept of the disease triangle in which environment impacts disease severity.

  20. Activities of muscadine grape skin and quercetin against Helicobacter pylori infection in mice.

    PubMed

    Brown, J C; Wang, J; Kasman, L; Jiang, X; Haley-Zitlin, V

    2011-01-01

    To explore the preventative potential of muscadine grape skin (MGS) and the single flavonoid, quercetin, as an alternative means for ameliorating Helicobacter pylori infection and/or the H. pylori-induced inflammatory response in mice. The antimicrobial and anti-inflammatory properties of MGS and quercetin, a major phenolic constituent, were evaluated against H. pylori in vitro and in vivo. The antimicrobial activity of quercetin was evaluated against 11 H. pylori strains in vitro with inhibition of all strains at 128-64 μg ml(-1) . In vivo studies showed a moderate reduction in H. pylori counts following treatment with 5 and 10% MGS or quercetin (25 mg kg(-1) body weight) in addition to significantly reduced inflammatory cytokines (TNF-α, IL-1β and IFN-γ) when compared with untreated mice. MGS and quercetin did not significantly reduce H. pylori growth in a mouse model. However, these products were effective in regulating the inflammatory response to H. pylori infection. Our results suggest that H. pylori infection may be reduced or prevented via the consumption of fruits rich in certain phenolic compounds (e.g. quercetin) such as muscadine grapes. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

  1. The Secreted Protease PrtA Controls Cell Growth, Biofilm Formation and Pathogenicity in Xylella fastidiosa

    PubMed Central

    Gouran, Hossein; Gillespie, Hyrum; Nascimento, Rafael; Chakraborty, Sandeep; Zaini, Paulo A.; Jacobson, Aaron; Phinney, Brett S.; Dolan, David; Durbin-Johnson, Blythe P.; Antonova, Elena S.; Lindow, Steven E.; Mellema, Matthew S.; Goulart, Luiz R.; Dandekar, Abhaya M.

    2016-01-01

    Pierce’s disease (PD) is a deadly disease of grapevines caused by the Gram-negative bacterium Xylella fastidiosa. Though disease symptoms were formerly attributed to bacteria blocking the plant xylem, this hypothesis is at best overly simplistic. Recently, we used a proteomic approach to characterize the secretome of X. fastidiosa, both in vitro and in planta, and identified LesA as one of the pathogenicity factors of X. fastidiosa in grapevines that leads to leaf scorching and chlorosis. Herein, we characterize another such factor encoded by PD0956, designated as an antivirulence secreted protease “PrtA” that displays a central role in controlling in vitro cell proliferation, length, motility, biofilm formation, and in planta virulence. The mutant in X. fastidiosa exhibited reduced cell length, hypermotility (and subsequent lack of biofilm formation) and hypervirulence in grapevines. These findings are supported by transcriptomic and proteomic analyses with corresponding plant infection data. Of particular interest, is the hypervirulent response in grapevines observed when X. fastidiosa is disrupted for production of PrtA, and that PD-model tobacco plants transformed to express PrtA exhibited decreased symptoms after infection by X. fastidiosa. PMID:27492542

  2. Impact of Plasmopara viticola infection of Merlot and Cabernet Sauvignon grapes on wine composition and flavor.

    PubMed

    Pons, Alexandre; Mouakka, Nadia; Deliere, Laurent; Crachereau, Jean Christophe; Davidou, Ludivine; Sauris, Pierre; Guilbault, Pascal; Darriet, Philippe

    2018-01-15

    This work reports the identification of volatile compounds involved in the particular and atypical flavor detected in Vitis vinifera red Merlot and Cabernet Sauvignon wines made with grapes infected and wilted by brown rot (Plasmopara viticola). Must made from withered grapes had green aromas while red wines were marked by intense odor reminiscent of green, herbaceous notes but also figs and cooked fruit. Thanks to GC-O and GC-MS analysis, cooked fruit notes were identified as 3-methyl-2,4-nonanedione, γ-nonalactone and γ-decalactone, whereas herbaceous and green aromas were identified as (Z)-1,5-octadien-3-one and 3-isobutyl-2-methoxypyrazine. We show that the organoleptic impact of P. viticola is more pronounced in Merlot wines compared to Cabernet Sauvignon ones. The highest levels of 3-methyl-2,4-nonanedione (75.3ng/L) were found in old Merlot wines made with 20% infected berries, suggesting the incidence of berry quality on the ability of a wine to age. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. A rhamnose-rich O-antigen mediates adhesion, virulence, and host colonization for the xylem-limited phytopathogen Xylella fastidiosa.

    PubMed

    Clifford, Jennifer C; Rapicavoli, Jeannette N; Roper, M Caroline

    2013-06-01

    Xylella fastidiosa is a gram-negative, xylem-limited bacterium that causes a lethal disease of grapevine called Pierce's disease. Lipopolysaccharide (LPS) composes approximately 75% of the outer membrane of gram-negative bacteria and, because it is largely displayed on the cell surface, it mediates interactions between the bacterial cell and its surrounding environment. LPS is composed of a conserved lipid A-core oligosaccharide component and a variable O-antigen portion. By targeting a key O-antigen biosynthetic gene, we demonstrate the contribution of the rhamnose-rich O-antigen to surface attachment, cell-cell aggregation, and biofilm maturation: critical steps for successful infection of the host xylem tissue. Moreover, we have demonstrated that a fully formed O-antigen moiety is an important virulence factor for Pierce's disease development in grape and that depletion of the O-antigen compromises its ability to colonize the host. It has long been speculated that cell-surface polysaccharides play a role in X. fastidiosa virulence and this study confirms that LPS is a major virulence factor for this important agricultural pathogen.

  4. Biochemical changes in grape rootstocks resulted from humic acid treatments in relation to nematode infection

    PubMed Central

    Kesba, Hosny H; El-Beltagi, Hossam S

    2012-01-01

    Objective To investigate the effect of humic acid on nematode infected, resistant and susceptible grapes in relation to lipid peroxidation and antioxidant mechanisms on selected biochemical parameters known as proactive substances. Methods The grape rootstocks, superior, superior/freedom and freedom were reacted differently to Meloidogyne incognita and Rotylenchulus reniformis according to rootstock progenitor. Two weeks after inoculation, two commercial products of humic acid were applied at the rate of (2, 4 mL or grams/plant) as soil drench. After 4 months, nematode soil populations were extracted and counted. A subsample of roots from each plant was stained and gall numbers, embedded stages per root were calculated, final population, nematode build up (Pf/Pi), average of eggs/eggmass were estimated. Subsamples of fresh root of each treatment were chemically analyzed. Results Freedom reduced significantly the nematode criteria and build up. Humic acid granules appeared to be more suppressive to nematode build up on superior and the higher dose on superior/freedom than liquid treatments. On freedom, all treatments reduced significantly the nematode build up regardless to the material nature. The higher dose was more effective than the lower one. As a result of humic acid applications, the malondialdehyde (MDA) and H2O2 contents were significantly reduced after humic acid treatments while the antioxidant compounds glutathione (GSH), ascorbic acid (ASA) and total phenol contents were significantly increased when compared with check. Antioxidant defense enzymes ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT) and polyphenol oxidase (PPO)showed significant increase in their specific activities in treated plants compared with nematode treated check. Conclusions Humic acid treatments improve the yield of grape by increasing the contents of antioxidant compounds and the specific activities of antioxidant enzymes. PMID:23569915

  5. Biochemical changes in grape rootstocks resulted from humic acid treatments in relation to nematode infection.

    PubMed

    Kesba, Hosny H; El-Beltagi, Hossam S

    2012-04-01

    To investigate the effect of humic acid on nematode infected, resistant and susceptible grapes in relation to lipid peroxidation and antioxidant mechanisms on selected biochemical parameters known as proactive substances. The grape rootstocks, superior, superior/freedom and freedom were reacted differently to Meloidogyne incognita and Rotylenchulus reniformis according to rootstock progenitor. Two weeks after inoculation, two commercial products of humic acid were applied at the rate of (2, 4 mL or grams/plant) as soil drench. After 4 months, nematode soil populations were extracted and counted. A subsample of roots from each plant was stained and gall numbers, embedded stages per root were calculated, final population, nematode build up (Pf/Pi), average of eggs/eggmass were estimated. Subsamples of fresh root of each treatment were chemically analyzed. Freedom reduced significantly the nematode criteria and build up. Humic acid granules appeared to be more suppressive to nematode build up on superior and the higher dose on superior/freedom than liquid treatments. On freedom, all treatments reduced significantly the nematode build up regardless to the material nature. The higher dose was more effective than the lower one. As a result of humic acid applications, the malondialdehyde (MDA) and H2O2 contents were significantly reduced after humic acid treatments while the antioxidant compounds glutathione (GSH), ascorbic acid (ASA) and total phenol contents were significantly increased when compared with check. Antioxidant defense enzymes ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT) and polyphenol oxidase (PPO)showed significant increase in their specific activities in treated plants compared with nematode treated check. Humic acid treatments improve the yield of grape by increasing the contents of antioxidant compounds and the specific activities of antioxidant enzymes.

  6. Differentiation of Xylella fastidiosa strains via multilocus sequence analysis of environmentally mediated genes (MLSA-E).

    PubMed

    Parker, Jennifer K; Havird, Justin C; De La Fuente, Leonardo

    2012-03-01

    Isolates of the plant pathogen Xylella fastidiosa are genetically very similar, but studies on their biological traits have indicated differences in virulence and infection symptomatology. Taxonomic analyses have identified several subspecies, and phylogenetic analyses of housekeeping genes have shown broad host-based genetic differences; however, results are still inconclusive for genetic differentiation of isolates within subspecies. This study employs multilocus sequence analysis of environmentally mediated genes (MLSA-E; genes influenced by environmental factors) to investigate X. fastidiosa relationships and differentiate isolates with low genetic variability. Potential environmentally mediated genes, including host colonization and survival genes related to infection establishment, were identified a priori. The ratio of the rate of nonsynonymous substitutions to the rate of synonymous substitutions (dN/dS) was calculated to select genes that may be under increased positive selection compared to previously studied housekeeping genes. Nine genes were sequenced from 54 X. fastidiosa isolates infecting different host plants across the United States. Results of maximum likelihood (ML) and Bayesian phylogenetic (BP) analyses are in agreement with known X. fastidiosa subspecies clades but show novel within-subspecies differentiation, including geographic differentiation, and provide additional information regarding host-based isolate variation and specificity. dN/dS ratios of environmentally mediated genes, though <1 due to high sequence similarity, are significantly greater than housekeeping gene dN/dS ratios and correlate with increased sequence variability. MLSA-E can more precisely resolve relationships between closely related bacterial strains with low genetic variability, such as X. fastidiosa isolates. Discovering the genetic relationships between X. fastidiosa isolates will provide new insights into the epidemiology of populations of X. fastidiosa, allowing

  7. Diffusible Signal Factor (DSF) Synthase RpfF of Xylella fastidiosa Is a Multifunction Protein Also Required for Response to DSF

    PubMed Central

    Ionescu, Michael; Baccari, Clelia; Da Silva, Aline Maria; Garcia, Angelica; Yokota, Kenji

    2013-01-01

    Xylella fastidiosa, like related Xanthomonas species, employs an Rpf cell-cell communication system consisting of a diffusible signal factor (DSF) synthase, RpfF, and a DSF sensor, RpfC, to coordinate expression of virulence genes. While phenotypes of a ΔrpfF strain in Xanthomonas campestris could be complemented by its own DSF, the DSF produced by X. fastidiosa (XfDSF) did not restore expression of the XfDSF-dependent genes hxfA and hxfB to a ΔrpfF strain of X. fastidiosa, suggesting that RpfF is involved in XfDSF sensing or XfDSF-dependent signaling. To test this conjecture, rpfC and rpfF of X. campestris were replaced by those of X. fastidiosa, and the contribution of each gene to the induction of a X. campestris DSF-dependent gene was assessed. As in X. fastidiosa, XfDSF-dependent signaling required both X. fastidiosa proteins RpfF and RpfC. RpfF repressed RpfC signaling activity, which in turn was derepressed by XfDSF. A mutated X. fastidiosa RpfF protein with two substitutions of glutamate to alanine in its active site was incapable of XfDSF production yet enabled a response to XfDSF, indicating that XfDSF production and the response to XfDSF are two separate functions in which RpfF is involved. This mutant was also hypervirulent to grape, demonstrating the antivirulence effects of XfDSF itself in X. fastidiosa. The Rpf system of X. fastidiosa is thus a novel example of a quorum-sensing signal synthase that is also involved in the response to the signal molecule that it synthesizes. PMID:24056101

  8. Diffusible signal factor (DSF) synthase RpfF of Xylella fastidiosa is a multifunction protein also required for response to DSF.

    PubMed

    Ionescu, Michael; Baccari, Clelia; Da Silva, Aline Maria; Garcia, Angelica; Yokota, Kenji; Lindow, Steven E

    2013-12-01

    Xylella fastidiosa, like related Xanthomonas species, employs an Rpf cell-cell communication system consisting of a diffusible signal factor (DSF) synthase, RpfF, and a DSF sensor, RpfC, to coordinate expression of virulence genes. While phenotypes of a ΔrpfF strain in Xanthomonas campestris could be complemented by its own DSF, the DSF produced by X. fastidiosa (XfDSF) did not restore expression of the XfDSF-dependent genes hxfA and hxfB to a ΔrpfF strain of X. fastidiosa, suggesting that RpfF is involved in XfDSF sensing or XfDSF-dependent signaling. To test this conjecture, rpfC and rpfF of X. campestris were replaced by those of X. fastidiosa, and the contribution of each gene to the induction of a X. campestris DSF-dependent gene was assessed. As in X. fastidiosa, XfDSF-dependent signaling required both X. fastidiosa proteins RpfF and RpfC. RpfF repressed RpfC signaling activity, which in turn was derepressed by XfDSF. A mutated X. fastidiosa RpfF protein with two substitutions of glutamate to alanine in its active site was incapable of XfDSF production yet enabled a response to XfDSF, indicating that XfDSF production and the response to XfDSF are two separate functions in which RpfF is involved. This mutant was also hypervirulent to grape, demonstrating the antivirulence effects of XfDSF itself in X. fastidiosa. The Rpf system of X. fastidiosa is thus a novel example of a quorum-sensing signal synthase that is also involved in the response to the signal molecule that it synthesizes.

  9. Time course of colonization of the glassy-winged sharpshooter precibarium by Xylella fastidiosa provides evidence for two types of egestion during inoculation

    USDA-ARS?s Scientific Manuscript database

    Introduction of the glassy-winged sharpshooter (GWSS) into California has caused an increase in incidence of Pierce’s Disease in grape-growing regions. Although host plant resistance to the causative bacterium, Xylella fastidiosa, and/or its GWSS vector is being sought, research is hampered by lack...

  10. Xylella fastidiosa is associated with reduced yield and altered fruit quality in a rabbiteye blueberry orchard in Louisiana but does not appear to spread rapidly

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a bacterial pathogen that causes diseases such as Pierce’s disease of grape, bacterial leaf scorch of shade trees, and citrus variegated chlorosis. Work by researchers in Georgia and Florida has shown that it is the cause of bacterial leaf scorch of Southern highbush blueberrie...

  11. Comparative protein profile analysis of wines made from Botrytis cinerea infected and healthy grapes reveals a novel biomarker for gushing in sparkling wine.

    PubMed

    Kupfer, Veronika M; Vogt, Elisabeth I; Ziegler, Tobias; Vogel, Rudi F; Niessen, Ludwig

    2017-09-01

    Fungal infection of grapes with the plant pathogenic fungus Botrytis (B.) cinerea was shown to cause a degradation of proteins in the resulting wine. Moreover, it influences the foaming properties of the wine. The aim of this study was to compare the protein composition in B. cinerea infected and healthy grapes and of wines produced from such grapes as well as to analyze whether the resulting changes in the protein profiles can be related the occurrence of gushing in sparkling wine. SDS-PAGE and reversed phase HPLC were applied to analyze the protein composition of healthy and botrytized grapes and of wines made from botrytized and healthy grapes. B. cinerea infection led to a general decrease of protein content in infected grapes and wines suggesting proteolytic activity of this fungus. Especially the concentration of a protein with a protein band at ~17kDa underwent a significant decrease in wine made from infected grapes. This protein was identified as Seripauperin 5 (PAU5) from Saccharomyces cerevisiae. A degradation of PAU5 and other proteins and the occurrence of a laccase from B. cinerea were observed in a gushing sparkling wine. Screening of sparkling wines showed that samples lacking PAU5 had a high probability for the occurrence of gushing. We suggest that the absence of protein PAU5 might be a useful biomarker for the occurrence of gushing in sparkling wine. Copyright © 2017. Published by Elsevier Ltd.

  12. Insights into the Activity and Substrate Binding of Xylella fastidiosa Polygalacturonase by Modification of a Unique QMK Amino Acid Motif Using Protein Chimeras

    PubMed Central

    Warren, Jeremy G.; Lincoln, James E.; Kirkpatrick, Bruce C.

    2015-01-01

    Polygalacturonases (EC 3.2.1.15) catalyze the random hydrolysis of 1, 4-alpha-D-galactosiduronic linkages in pectate and other galacturonans. Xylella fastidiosa possesses a single polygalacturonase gene, pglA (PD1485), and X. fastidiosa mutants deficient in the production of polygalacturonase are non-pathogenic and show a compromised ability to systemically infect grapevines. These results suggested that grapevines expressing sufficient amounts of an inhibitor of X. fastidiosa polygalacturonase might be protected from disease. Previous work in our laboratory and others have tried without success to produce soluble active X. fastidiosa polygalacturonase for use in inhibition assays. In this study, we created two enzymatically active X. fastidiosa / A. vitis polygalacturonase chimeras, AX1A and AX2A to explore the functionality of X. fastidiosa polygalacturonase in vitro. The AX1A chimera was constructed to specifically test if recombinant chimeric protein, produced in Escherichia coli, is soluble and if the X. fastidiosa polygalacturonase catalytic amino acids are able to hydrolyze polygalacturonic acid. The AX2A chimera was constructed to evaluate the ability of a unique QMK motif of X. fastidiosa polygalacturonase, most polygalacturonases have a R(I/L)K motif, to bind to and allow the hydrolysis of polygalacturonic acid. Furthermore, the AX2A chimera was also used to explore what effect modification of the QMK motif of X. fastidiosa polygalacturonase to a conserved RIK motif has on enzymatic activity. These experiments showed that both the AX1A and AX2A polygalacturonase chimeras were soluble and able to hydrolyze the polygalacturonic acid substrate. Additionally, the modification of the QMK motif to the conserved RIK motif eliminated hydrolytic activity, suggesting that the QMK motif is important for the activity of X. fastidiosa polygalacturonase. This result suggests X. fastidiosa polygalacturonase may preferentially hydrolyze a different pectic substrate or

  13. Insights into the Activity and Substrate Binding of Xylella fastidiosa Polygalacturonase by Modification of a Unique QMK Amino Acid Motif Using Protein Chimeras.

    PubMed

    Warren, Jeremy G; Lincoln, James E; Kirkpatrick, Bruce C

    2015-01-01

    Polygalacturonases (EC 3.2.1.15) catalyze the random hydrolysis of 1, 4-alpha-D-galactosiduronic linkages in pectate and other galacturonans. Xylella fastidiosa possesses a single polygalacturonase gene, pglA (PD1485), and X. fastidiosa mutants deficient in the production of polygalacturonase are non-pathogenic and show a compromised ability to systemically infect grapevines. These results suggested that grapevines expressing sufficient amounts of an inhibitor of X. fastidiosa polygalacturonase might be protected from disease. Previous work in our laboratory and others have tried without success to produce soluble active X. fastidiosa polygalacturonase for use in inhibition assays. In this study, we created two enzymatically active X. fastidiosa / A. vitis polygalacturonase chimeras, AX1A and AX2A to explore the functionality of X. fastidiosa polygalacturonase in vitro. The AX1A chimera was constructed to specifically test if recombinant chimeric protein, produced in Escherichia coli, is soluble and if the X. fastidiosa polygalacturonase catalytic amino acids are able to hydrolyze polygalacturonic acid. The AX2A chimera was constructed to evaluate the ability of a unique QMK motif of X. fastidiosa polygalacturonase, most polygalacturonases have a R(I/L)K motif, to bind to and allow the hydrolysis of polygalacturonic acid. Furthermore, the AX2A chimera was also used to explore what effect modification of the QMK motif of X. fastidiosa polygalacturonase to a conserved RIK motif has on enzymatic activity. These experiments showed that both the AX1A and AX2A polygalacturonase chimeras were soluble and able to hydrolyze the polygalacturonic acid substrate. Additionally, the modification of the QMK motif to the conserved RIK motif eliminated hydrolytic activity, suggesting that the QMK motif is important for the activity of X. fastidiosa polygalacturonase. This result suggests X. fastidiosa polygalacturonase may preferentially hydrolyze a different pectic substrate or

  14. Distribution of Xylella fastidiosa in Sycamore associated with low temperature and host resistance

    Treesearch

    T.S.M. Henneberger; K.L. Stevenson; Kerry O. Britton; C.J. Chang

    2004-01-01

    Experiments were conducted in the field and laboratory to determine effects of low temperatures 4% on Xylella fastidiosa populations in American sycamore. Roots and shoots from naturally infected trees at two locations were collected monthly. Sap extracted from the samples was tested by enzyme-linked immunosorbent assay for presence of X...

  15. Evaluation of pathogenicity and insect transmission of Xylella fastidiosa strains to olive plants

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf) is a xylem-limited bacterium that causes disease in a number of economically important crops in California and worldwide. Newly observed scorching symptoms in olive trees may be due to Xf infection. If true, “olive leaf scorch disease” (OLSD) would represent a new threat to...

  16. High-throughput DNA isolation method for detection of Xylella fastidiosa in plant and insect samples.

    PubMed

    Brady, Jeff A; Faske, Jennifer B; Castañeda-Gill, Jessica M; King, Jonathan L; Mitchell, Forrest L

    2011-09-01

    We report an inexpensive, high-throughput method for isolating DNA from insect and plant samples for the purpose of detecting Xylella fastidiosa infection. Existing methods often copurify inhibitors of DNA polymerases, limiting their usefulness for PCR-based detection assays. When compared to commercially available kits, the method provides enhanced pathogen detection at a fraction of the cost.

  17. Occurrence and infection of Cladosporium, Fusarium, Epicoccum and Aureobasidium in withered rotten grapes during post-harvest dehydration.

    PubMed

    Lorenzini, Marilinda; Zapparoli, Giacomo

    2015-11-01

    Fungi like Cladosporium, Fusarium, Epicoccum and Aureobasidium can occur on withered grapes causing spoilage of passito wine. There is little or no information on the pathogenic role of these fungi. This study describes the isolation, incidence and identification of several isolates from different withered rotten grapes. Representative isolates grouped in several phenotypes were identified by phylogenetic analysis of internal transcribed spacer, actin or elongation factor gene sequences. Isolates of Cladosporium and Fusarium were ascribed to different species, of these C. ramotenellum, C. halotolerans and F. graminearum were isolated from Vitis vinifera for the first time. All Epicoccum and Aureobasidium isolates belonged to E. nigrum and A. pullulans, respectively. Random amplified DNA polymorphism analysis showed high level of heterogenicity among Epicoccum and Fusarium isolates. Infection assays were carried out to evaluate infectivity in some strains under different withering conditions. Fusarium spp. strains had similar infectivity, while significant variability was observed among Cladosporium spp. and E. nigrum strains. A. pullulans resulted particularly infective. This study provided insights into the occurrence and infection of these fungi in fruit-drying rooms with important implications towards control management during the withering.

  18. Draft genome sequence of Xylella fastidiosa subsp. fastidiosa strain Stag’s Leap

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa subsp. fastidiosa causes Pierce’s disease of grapevine. Presented here is the draft genome sequence of the Stag’s Leap strain, previously used in pathogenicity/virulence assays to evaluate grapevine germplasm bearing Pierce’s disease....

  19. Draft Genome Sequence of Xylella fastidiosa subsp. fastidiosa Strain Stag’s Leap

    PubMed Central

    Wu, F.; Zheng, Z.; Deng, X.; Burbank, L. P.; Stenger, D. C.

    2016-01-01

    Xylella fastidiosa subsp. fastidiosa causes Pierce’s disease of grapevine. Presented here is the draft genome sequence of the Stag’s Leap strain, previously used in pathogenicity/virulence assays to evaluate grapevine germplasm bearing Pierce’s disease resistance and a phenotypic assessment of knockout mutants to determine gene function. PMID:27103713

  20. RpfF-dependent regulon of Xylella fastidiosa.

    PubMed

    Wang, Nian; Li, Jian-Liang; Lindow, Steven E

    2012-11-01

    ABSTRACT Xylella fastidiosa regulates traits important to both virulence of grape as well as colonization of sharpshooter vectors via its production of a fatty acid signal molecule known as DSF whose production is dependent on rpfF. Although X. fastidiosa rpfF mutants exhibit increased virulence to plants, they are unable to be spread from plant to plant by insect vectors. To gain more insight into the traits that contribute to these processes, a whole-genome Agilent DNA microarray for this species was developed and used to determine the RpfF-dependent regulon by transcriptional profiling. In total, 446 protein coding genes whose expression was significantly different between the wild type and an rpfF mutant (false discovery rate < 0.05) were identified when cells were grown in PW liquid medium. Among them, 165 genes were downregulated in the rpfF mutant compared with the wild-type strain whereas 281 genes were over-expressed. RpfF function was required for regulation of 11 regulatory and σ factors, including rpfE, yybA, PD1177, glnB, rpfG, PD0954, PD0199, PD2050, colR, rpoH, and rpoD. In general, RpfF is required for regulation of genes involved in attachment and biofilm formation, enhancing expression of hemagglutinin genes hxfA and hxfB, and suppressing most type IV pili and gum genes. A large number of other RpfF-dependent genes that might contribute to virulence or insect colonization were also identified such as those encoding hemolysin and colicin V, as well as genes with unknown functions.

  1. Role of cyclic di-GMP in Xylella fastidiosa biofilm formation, plant virulence, and insect transmission.

    PubMed

    Chatterjee, Subhadeep; Killiny, Nabil; Almeida, Rodrigo P P; Lindow, Steven E

    2010-10-01

    Xylella fastidiosa must coordinately regulate a variety of traits contributing to biofilm formation, host plant and vector colonization, and transmission between plants. Traits such as production of extracellular polysaccharides (EPS), adhesins, extracellular enzymes, and pili are expressed in a cell-density-dependent fashion mediated by a cell-to-cell signaling system involving a fatty acid diffusible signaling factor (DSF). The expression of gene PD0279 (which has a GGDEF domain) is downregulated in the presence of DSF and may be involved in intracellular signaling by modulating the levels of cyclic di-GMP. PD0279, designated cyclic di-GMP synthase A (cgsA), is required for biofilm formation, plant virulence, and vector transmission. cgsA mutants exhibited a hyperadhesive phenotype in vitro and overexpressed gumJ, hxfA, hxfB, xadA, and fimA, which promote attachment of cells to surfaces and, hence, biofilm formation. The mutants were greatly reduced in virulence to grape albeit still transmissible by insect vectors, although at a reduced level compared with transmission rates of the wild-type strain, despite the fact that similar numbers of cells of the cgsA mutant were acquired by the insects from infected plants. High levels of EPS were measured in cgsA mutants compared with wild-type strains, and scanning electron microscopy analysis also revealed a thicker amorphous layer surrounding the mutants. Overexpression of cgsA in a cgsA-complemented mutant conferred the opposite phenotypes in vitro. These results suggest that decreases of cyclic di-GMP result from the accumulation of DSF as cell density increases, leading to a phenotypic transition from a planktonic state capable of colonizing host plants to an adhesive state that is insect transmissible.

  2. Transmission efficiency of Xylella fastidiosa by sharpshooters (Hemiptera: Cicadellidae) in coffee and citrus.

    PubMed

    Marucci, Rosangela C; Lopes, João R S; Cavichioli, Rodney R

    2008-08-01

    Xylella fastidiosa (Wells, Raju, Hung, Weisburg, Mandelco-Paul, and Brenner) is a bacterial pathogen transmitted by several sharpshooters in two tribes of Cicadellinae (Proconiini and Cicadellini). Here, we compared the transmission efficiency of X. fastidiosa in coffee (Coffea arabica L.) and citrus [Citrus sinensis (L.) Osbeck] by Cicadellini [Bucephalogonia xanthophis (Berg) and Dilobopterus costalimai Young] and Proconiini [Homalodisca ignorata Melichar and Oncometopia facialis (Signoret)] sharpshooters that occur in both crops. At different seasons, healthy adults of each species were submitted to a 48-h acquisition access period on citrus or coffee source plants infected with X. fastidiosa isolates that cause Citrus variegated chlorosis (CVC) and Coffee leaf scorch (CLS), respectively, and then confined on healthy seedlings of the corresponding host plant for a 48-h inoculation access period. No significant effect of inoculation season was observed when comparing infection rates of citrus or coffee plants inoculated by vectors at different times of the year. In citrus, the transmission rate by single insects was significantly higher for H. ignorata (30%) in relation to B. xanthophis (5%) and O. facialis (1.1%), but there was no difference among vector species in coffee, whose transmission rates ranged from 1.2 to 7.2%. Comparing host plants, H. ignorata was more effective in transmitting X. fastidiosa to citrus (30%) in relation to coffee (2.2%), whereas the other vectors transmitted the bacterium to both hosts with similar efficiencies. Despite these variations, vector efficiency in coffee and citrus is lower than that reported in other hosts.

  3. Large-scale intersubspecific recombination in the plant-pathogenic bacterium Xylella fastidiosa is associated with the host shift to mulberry.

    PubMed

    Nunney, Leonard; Schuenzel, Erin L; Scally, Mark; Bromley, Robin E; Stouthamer, Richard

    2014-05-01

    Homologous recombination plays an important role in the structuring of genetic variation of many bacteria; however, its importance in adaptive evolution is not well established. We investigated the association of intersubspecific homologous recombination (IHR) with the shift to a novel host (mulberry) by the plant-pathogenic bacterium Xylella fastidiosa. Mulberry leaf scorch was identified about 25 years ago in native red mulberry in the eastern United States and has spread to introduced white mulberry in California. Comparing a sequence of 8 genes (4,706 bp) from 21 mulberry-type isolates to published data (352 isolates representing all subspecies), we confirmed previous indications that the mulberry isolates define a group distinct from the 4 subspecies, and we propose naming the taxon X. fastidiosa subsp. morus. The ancestry of its gene sequences was mixed, with 4 derived from X. fastidiosa subsp. fastidiosa (introduced from Central America), 3 from X. fastidiosa subsp. multiplex (considered native to the United States), and 1 chimeric, demonstrating that this group originated by large-scale IHR. The very low within-type genetic variation (0.08% site polymorphism), plus the apparent inability of native X. fastidiosa subsp. multiplex to infect mulberry, suggests that this host shift was achieved after strong selection acted on genetic variants created by IHR. Sequence data indicate that a single ancestral IHR event gave rise not only to X. fastidiosa subsp. morus but also to the X. fastidiosa subsp. multiplex recombinant group which infects several hosts but is the only type naturally infecting blueberry, thus implicating this IHR in the invasion of at least two novel native hosts, mulberry and blueberry.

  4. Large-Scale Intersubspecific Recombination in the Plant-Pathogenic Bacterium Xylella fastidiosa Is Associated with the Host Shift to Mulberry

    PubMed Central

    Schuenzel, Erin L.; Scally, Mark; Bromley, Robin E.; Stouthamer, Richard

    2014-01-01

    Homologous recombination plays an important role in the structuring of genetic variation of many bacteria; however, its importance in adaptive evolution is not well established. We investigated the association of intersubspecific homologous recombination (IHR) with the shift to a novel host (mulberry) by the plant-pathogenic bacterium Xylella fastidiosa. Mulberry leaf scorch was identified about 25 years ago in native red mulberry in the eastern United States and has spread to introduced white mulberry in California. Comparing a sequence of 8 genes (4,706 bp) from 21 mulberry-type isolates to published data (352 isolates representing all subspecies), we confirmed previous indications that the mulberry isolates define a group distinct from the 4 subspecies, and we propose naming the taxon X. fastidiosa subsp. morus. The ancestry of its gene sequences was mixed, with 4 derived from X. fastidiosa subsp. fastidiosa (introduced from Central America), 3 from X. fastidiosa subsp. multiplex (considered native to the United States), and 1 chimeric, demonstrating that this group originated by large-scale IHR. The very low within-type genetic variation (0.08% site polymorphism), plus the apparent inability of native X. fastidiosa subsp. multiplex to infect mulberry, suggests that this host shift was achieved after strong selection acted on genetic variants created by IHR. Sequence data indicate that a single ancestral IHR event gave rise not only to X. fastidiosa subsp. morus but also to the X. fastidiosa subsp. multiplex recombinant group which infects several hosts but is the only type naturally infecting blueberry, thus implicating this IHR in the invasion of at least two novel native hosts, mulberry and blueberry. PMID:24610840

  5. High throughput PCR detection of Xylella fastidiosa directly from almond tissues.

    PubMed

    Chen, Jianchi; Livingston, Sam; Groves, Russell; Civerolo, Edwin L

    2008-04-01

    Xylella fastidiosa, the causal agent of almond leaf scorch disease (ALSD), is currently re-emerging as a serious concern in California. Efficient pathogen detection is critical for ALSD epidemiological studies, particularly when a large sample size is involved. We here report a PCR procedure to detect X. fastidiosa directly from infected almond tissue without the laborious DNA extraction. Plant samples were prepared by freeze-drying and pulverized. Appropriate dilutions of the pulverized freeze-dried tissue (PFT) were determined to minimize the effect of enzyme inhibitors from plant tissue and retain PCR detection of X. fastdiosa cells at a single digit number level. This PFT-PCR procedure was evaluated by comparing to the in vitro cultivation method using 102 symptomatic samples and resulted in a predictive value of 90.8%. PFT-PCR was further applied to monitor the seasonal occurrence of X. fastidiosa from four selected almond trees in two orchards in 2005. The results matched with those of the cultivation method at 92.3%. Considering the simplicity and reliability, we conclude that PFT-PCR is a valuable option for high throughput rapid detection of X. fastidiosa.

  6. Xylella fastidiosa outer membrane vesicles modulate plant colonization by blocking attachment to surfaces.

    PubMed

    Ionescu, Michael; Zaini, Paulo A; Baccari, Clelia; Tran, Sophia; da Silva, Aline M; Lindow, Steven E

    2014-09-16

    Outer membrane vesicles (OMVs) of Gram-negative bacteria have been studied intensively in recent years, primarily in their role in delivering virulence factors and antigens during pathogenesis. However, the near ubiquity of their production suggests that they may play other roles, such as responding to envelope stress or trafficking various cargoes to prevent dilution or degradation by other bacterial species. Here we show that OMVs produced by Xylella fastidiosa, a xylem-colonizing plant pathogenic bacterium, block its interaction with various surfaces such as the walls of xylem vessels in host plants. The release of OMVs was suppressed by the diffusible signal factor-dependent quorum-sensing system, and a X. fastidiosa ΔrpfF mutant in which quorum signaling was disrupted was both much more virulent to plants and less adhesive to glass and plant surfaces than the WT strain. The higher virulence of the ΔrpfF mutant was associated with fivefold higher numbers of OMVs recovered from xylem sap of infected plants. The frequency of attachment of X. fastidiosa to xylem vessels was 20-fold lower in the presence of OMVs than in their absence. OMV production thus is a strategy used by X. fastidiosa cells to adjust attachment to surfaces in its transition from adhesive cells capable of insect transmission to an "exploratory" lifestyle for systemic spread within the plant host which would be hindered by attachment. OMV production may contribute to the movement of other bacteria in porous environments by similarly reducing their contact with environmental constituents.

  7. Development of single chain variable fragment (scFv) antibodies against Xylella fastidiosa subsp. pauca by phage display.

    PubMed

    Yuan, Qing; Jordan, Ramon; Brlansky, Ronald H; Istomina, Olga; Hartung, John

    2015-10-01

    Xylella fastidiosa is a member of the gamma proteobacteria. It is fastidious, insect-vectored and xylem-limited and causes a variety of diseases, some severe, on a wide range of economically important perennial crops, including grape and citrus. Antibody based detection assays are commercially available for X. fastidiosa, and are effective at the species, but not at the subspecies level. We have made a library of scFv antibody fragments directed against X. fastidiosa subsp. pauca strain 9a5c (citrus) by using phage display technology. Antibody gene repertoires were PCR-amplified using 23 primers for the heavy chain variable region (V(H)) and 21 primers for the light chain variable region (V(L)). The V(H) and V(L) were joined by overlap extension PCR, and then the genes of the scFv library were ligated into the phage vector pKM19. The library contained 1.2×10(7) independent clones with full-length scFv inserts. In each of 3cycles of affinity-selection with 9a5c, about 1.0×10(12) phage were used for panning with 4.1×10(6), 7.1×10(6), 2.1×10(7) phage recovered after the first, second and third cycles, respectively. Sixty-six percent of clones from the final library bound X. fastidiosa 9a5c in an ELISA. Some of these scFv antibodies recognized strain 9a5c and did not recognize X. fastidiosa strains that cause Pierce's disease of grapevine.

  8. Initial biochemical and functional characterization of a 5'-nucleotidase from Xylella fastidiosa related to the human cytosolic 5'-nucleotidase I.

    PubMed

    Santos, Clelton A; Saraiva, Antonio M; Toledo, Marcelo A S; Beloti, Lilian L; Crucello, Aline; Favaro, Marianna T P; Horta, Maria A C; Santiago, André S; Mendes, Juliano S; Souza, Alessandra A; Souza, Anete P

    2013-01-01

    The 5'-nucleotidases constitute a ubiquitous family of enzymes that catalyze either the hydrolysis or the transfer of esterified phosphate at the 5' position of nucleoside monophosphates. These enzymes are responsible for the regulation of nucleotide and nucleoside levels in the cell and can interfere with the phosphorylation-dependent activation of nucleoside analogs used in therapies targeting solid tumors and viral infections. In the present study, we report the initial biochemical and functional characterization of a 5'-nucleotidase from Xylella fastidiosa that is related to the human cytosolic 5'-nucleotidase I. X. fastidiosa is a plant pathogenic bacterium that is responsible for numerous economically important crop diseases. Biochemical assays confirmed the phosphatase activity of the recombinant purified enzyme and revealed metal ion dependence for full enzyme activity. In addition, we investigated the involvement of Xf5'-Nt in the formation of X. fastidiosa biofilms, which are structures that occlude the xylem vessels of susceptible plants and are strictly associated with bacterial pathogenesis. Using polyclonal antibodies against Xf5'-Nt, we observed an overexpression of Xf5'-Nt during the initial phases of X. fastidiosa biofilm formation that was not observed during X. fastidiosa planktonic growth. Our results demonstrate that the de/phosphorylation network catalyzed by 5'-nucleotidases may play an important role in bacterial biofilm formation, thereby contributing novel insights into bacterial nucleotide metabolism and pathogenicity.

  9. Molecular characteristics and efficacy of 16D10 siRNAs in inhibiting root-knot nematode infection in transgenic grape hairy roots

    USDA-ARS?s Scientific Manuscript database

    Root-knot nematodes (RKNs) infect many annual and perennial crops and are the most devastating soil-born pests in vineyards. To develop a biotech-based solution for controlling RKNs in grapes, we evaluated the efficacy of plant-derived RNA interference (RNAi) silencing of a conserved RKN effector ge...

  10. Three New Pierce's Disease Pathogenicity Effectors Identified Using Xylella fastidiosa Biocontrol Strain EB92-1

    PubMed Central

    Zhang, Shujian; Chakrabarty, Pranjib K.; Fleites, Laura A.; Rayside, Patricia A.; Hopkins, Donald L.; Gabriel, Dean W.

    2015-01-01

    Xylella fastidiosa (X. fastidiosa) infects a wide range of plant hosts and causes economically serious diseases, including Pierce's Disease (PD) of grapevines. X. fastidiosa biocontrol strain EB92-1 was isolated from elderberry and is infectious and persistent in grapevines but causes only very slight symptoms under ideal conditions. The draft genome of EB92-1 revealed that it appeared to be missing genes encoding 10 potential PD pathogenicity effectors found in Temecula1. Subsequent PCR and sequencing analyses confirmed that EB92-1 was missing the following predicted effectors found in Temecula1: two type II secreted enzymes, including a lipase (LipA; PD1703) and a serine protease (PD0956); two identical genes encoding proteins similar to Zonula occludens toxins (Zot; PD0915 and PD0928), and at least one relatively short, hemagglutinin-like protein (PD0986). Leaves of tobacco and citrus inoculated with cell-free, crude protein extracts of E. coli BL21(DE3) overexpressing PD1703 exhibited a hypersensitive response (HR) in less than 24 hours. When cloned into shuttle vector pBBR1MCS-5, PD1703 conferred strong secreted lipase activity to Xanthomonas citri, E. coli and X. fastidiosa EB92-1 in plate assays. EB92-1/PD1703 transformants also showed significantly increased disease symptoms on grapevines, characteristic of PD. Genes predicted to encode PD0928 (Zot) and a PD0986 (hemagglutinin) were also cloned into pBBR1MCS-5 and moved into EB92-1; both transformants also showed significantly increased symptoms on V. vinifera vines, characteristic of PD. Together, these results reveal that PD effectors include at least a lipase, two Zot-like toxins and a possibly redundant hemagglutinin, none of which are necessary for parasitic survival of X. fastidiosa populations in grapevines or elderberry. PMID:26218423

  11. Seasonal abundance of Draeculacephala minerva and other Xylella fastidiosa vectors in California almond orchards and vineyards.

    PubMed

    Daane, Kent M; Wistrom, Christina M; Shapland, Elaine B; Sisterson, Mark S

    2011-04-01

    Almond leaf scorch (ALS) disease is caused by the bacterium Xylella fastidiosa and transmitted by xylem-feeding insects. Reports of increased incidence of ALS-diseased trees in California prompted surveys in three almond [Prunus dulcis (Mill.) D. A. Webb]-growing regions, from June 2003 to September 2005, to determine insect vector species composition and abundance. For comparison, sampling in and near vineyards in the San Joaquin Valley, California, also was completed. Sampling in or near almond orchards collected >42,000 Cicadomorpha of which 4.8% were xylem feeders, including 1912 grass sharpshooter, Draeculacephala minerva Ball; five Xyphon fulgida Nottingham; and a single spittlebug, Philaenus spumarius L. The most abundant vector was D. minerva. Season-long sampling indicated that D. minerva was a year-round resident in and/or near almonds in the Sacramento Valley, but not in the San Joaquin Valley. Similarly, D. minerca was rare in vineyards in the San Joaquin Valley, but was abundant in irrigated pastures near vineyards. D. minerva was most frequently collected along orchard margins, and peak densities were observed in summer, the period of time when bacterial titers are reported to increase in infected trees. Screening of D. minerva for presence of X.fastidiosa found that 1.1% of insects collected near almond orchards and 4.5% of insects collected from pastures tested positive. The X. fastidiosa subspecies and genotype detected in insects collected from orchards matched those collected from ALS-diseased almond trees in the same orchard. Of the few X. fulgida and P. spumarius collected, none tested positive for X. fastidiosa. Results are discussed with respect to X. fastidiosa vector control and detection methods.

  12. Three New Pierce's Disease Pathogenicity Effectors Identified Using Xylella fastidiosa Biocontrol Strain EB92-1.

    PubMed

    Zhang, Shujian; Chakrabarty, Pranjib K; Fleites, Laura A; Rayside, Patricia A; Hopkins, Donald L; Gabriel, Dean W

    2015-01-01

    Xylella fastidiosa (X. fastidiosa) infects a wide range of plant hosts and causes economically serious diseases, including Pierce's Disease (PD) of grapevines. X. fastidiosa biocontrol strain EB92-1 was isolated from elderberry and is infectious and persistent in grapevines but causes only very slight symptoms under ideal conditions. The draft genome of EB92-1 revealed that it appeared to be missing genes encoding 10 potential PD pathogenicity effectors found in Temecula1. Subsequent PCR and sequencing analyses confirmed that EB92-1 was missing the following predicted effectors found in Temecula1: two type II secreted enzymes, including a lipase (LipA; PD1703) and a serine protease (PD0956); two identical genes encoding proteins similar to Zonula occludens toxins (Zot; PD0915 and PD0928), and at least one relatively short, hemagglutinin-like protein (PD0986). Leaves of tobacco and citrus inoculated with cell-free, crude protein extracts of E. coli BL21(DE3) overexpressing PD1703 exhibited a hypersensitive response (HR) in less than 24 hours. When cloned into shuttle vector pBBR1MCS-5, PD1703 conferred strong secreted lipase activity to Xanthomonas citri, E. coli and X. fastidiosa EB92-1 in plate assays. EB92-1/PD1703 transformants also showed significantly increased disease symptoms on grapevines, characteristic of PD. Genes predicted to encode PD0928 (Zot) and a PD0986 (hemagglutinin) were also cloned into pBBR1MCS-5 and moved into EB92-1; both transformants also showed significantly increased symptoms on V. vinifera vines, characteristic of PD. Together, these results reveal that PD effectors include at least a lipase, two Zot-like toxins and a possibly redundant hemagglutinin, none of which are necessary for parasitic survival of X. fastidiosa populations in grapevines or elderberry.

  13. Detecting genetic introgression: high levels of intersubspecific recombination found in Xylella fastidiosa in Brazil.

    PubMed

    Nunney, Leonard; Yuan, Xiaoli; Bromley, Robin E; Stouthamer, Richard

    2012-07-01

    Documenting the role of novel mutation versus homologous recombination in bacterial evolution, and especially in the invasion of new hosts, is central to understanding the long-term dynamics of pathogenic bacteria. We used multilocus sequence typing (MLST) to study this issue in Xylella fastidiosa subsp. pauca from Brazil, a bacterium causing citrus variegated chlorosis (CVC) and coffee leaf scorch (CLS). All 55 citrus isolates typed (plus one coffee isolate) defined three similar sequence types (STs) dominated by ST11 (85%), while the remaining 22 coffee isolates defined two STs, mainly ST16 (74%). This low level of variation masked unusually large allelic differences (>1% divergence with no intermediates) at five loci (leuA, petC, malF, cysG, and holC). We developed an introgression test to detect whether these large differences were due to introgression via homologous recombination from another X. fastidiosa subspecies. Using additional sequencing around these loci, we established that the seven randomly chosen MLST targets contained seven regions of introgression totaling 2,172 bp of 4,161 bp (52%), only 409 bp (10%) of which were detected by other recombination tests. This high level of introgression suggests the hypothesis that X. fastidiosa subsp. pauca became pathogenic on citrus and coffee (crops cultivated in Brazil for several hundred years) only recently after it gained genetic variation via intersubspecific recombination, facilitating a switch from native hosts. A candidate donor is the subspecies infecting plum in the region since 1935 (possibly X. fastidiosa subsp. multiplex). This hypothesis predicts that nonrecombinant native X. fastidiosa subsp. pauca (not yet isolated) does not cause disease in citrus or coffee.

  14. A TaqMan-based real time PCR assay for specific detection and quantification of Xylella fastidiosa strains causing bacterial leaf scorch in oleander.

    PubMed

    Guan, Wei; Shao, Jonathan; Singh, Raghuwinder; Davis, Robert E; Zhao, Tingchang; Huang, Qi

    2013-02-15

    A TaqMan-based real-time PCR assay was developed for specific detection of strains of X. fastidiosa causing oleander leaf scorch. The assay uses primers WG-OLS-F1 and WG-OLS-R1 and the fluorescent probe WG-OLS-P1, designed based on unique sequences found only in the genome of oleander strain Ann1. The assay is specific, allowing detection of only oleander-infecting strains, not other strains of X. fastidiosa nor other plant-associated bacteria tested. The assay is also sensitive, with a detection limit of 10.4fg DNA of X. fastidiosa per reaction in vitro and in planta. The assay can also be applied to detect low numbers of X. fastidiosa in insect samples, or further developed into a multiplex real-time PCR assay to simultaneously detect and distinguish diverse strains of X. fastidiosa that may occupy the same hosts or insect vectors. Specific and sensitive detection and quantification of oleander strains of X. fastidiosa should be useful for disease diagnosis, epidemiological studies, management of oleander leaf scorch disease, and resistance screening for oleander shrubs.

  15. Xylella fastidiosa disturbs nitrogen metabolism and causes a stress response in sweet orange Citrus sinensis cv. Pera.

    PubMed

    Purcino, Rúbia P; Medina, Camilo Lázaro; Martins de Souza, Daniel; Winck, Flávia Vischi; Machado, Eduardo Caruso; Novello, José Camilo; Machado, Marcos Antonio; Mazzafera, Paulo

    2007-01-01

    Xylella fastidiosa (Xf) is a fastidious bacterium that grows exclusively in the xylem of several important crop species, including grape and sweet orange (Citrus sinensis L. Osb.) causing Pierce disease and citrus variegated chlorosis (CVC), respectively. The aim of this work was to study the nitrogen metabolism of a highly susceptible variety of sweet orange cv. 'Pêra' (C. sinensis L. Osbeck) infected with Xf. Plants were artificially infected and maintained in the greenhouse until they have developed clear disease symptoms. The content of nitrogen compounds and enzymes of the nitrogen metabolism and proteases in the xylem sap and leaves of diseased (DP) and uninfected healthy (HP) plants was studied. The activity of nitrate reductase in leaves did not change in DP, however, the activity of glutamine synthetase was significantly higher in these leaves. Although amino acid concentration was slightly higher in the xylem sap of DP, the level dropped drastically in the leaves. The protein contents were lower in the sap and in leaves of DP. DP and HP showed the same amino acid profiles, but different proportions were observed among them, mainly for asparagine, glutamine, and arginine. The polyamine putrescine was found in high concentrations only in DP. Protease activity was higher in leaves of DP while, in the xylem sap, activity was detected only in DP. Bidimensional electrophoresis showed a marked change in the protein pattern in DP. Five differentially expressed proteins were identified (2 from HP and 3 from DP), but none showed similarity with the genomic (translated) and proteomic database of Xf, but do show similarity with the proteins thaumatin, mucin, peroxidase, ABC-transporter, and strictosidine synthase. These results showed that significant changes take place in the nitrogen metabolism of DP, probably as a response to the alterations in the absorption, assimilation and distribution of N in the plant.

  16. A temperature-independent cold-shock protein homolog acts as a virulence factor in Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf), causal agent of Pierce’s Disease (PD) of grapevine, is mainly prevalent in warmer climates. Subjecting Xf-infected grapevines to cold temperatures can, in many cases, effectively eliminate the bacterial population. However, little is known regarding physiological responses o...

  17. Improved classification accuracy of powdery mildew infection levels of wine grapes by spatial-spectral analysis of hyperspectral images.

    PubMed

    Knauer, Uwe; Matros, Andrea; Petrovic, Tijana; Zanker, Timothy; Scott, Eileen S; Seiffert, Udo

    2017-01-01

    Hyperspectral imaging is an emerging means of assessing plant vitality, stress parameters, nutrition status, and diseases. Extraction of target values from the high-dimensional datasets either relies on pixel-wise processing of the full spectral information, appropriate selection of individual bands, or calculation of spectral indices. Limitations of such approaches are reduced classification accuracy, reduced robustness due to spatial variation of the spectral information across the surface of the objects measured as well as a loss of information intrinsic to band selection and use of spectral indices. In this paper we present an improved spatial-spectral segmentation approach for the analysis of hyperspectral imaging data and its application for the prediction of powdery mildew infection levels (disease severity) of intact Chardonnay grape bunches shortly before veraison. Instead of calculating texture features (spatial features) for the huge number of spectral bands independently, dimensionality reduction by means of Linear Discriminant Analysis (LDA) was applied first to derive a few descriptive image bands. Subsequent classification was based on modified Random Forest classifiers and selective extraction of texture parameters from the integral image representation of the image bands generated. Dimensionality reduction, integral images, and the selective feature extraction led to improved classification accuracies of up to [Formula: see text] for detached berries used as a reference sample (training dataset). Our approach was validated by predicting infection levels for a sample of 30 intact bunches. Classification accuracy improved with the number of decision trees of the Random Forest classifier. These results corresponded with qPCR results. An accuracy of 0.87 was achieved in classification of healthy, infected, and severely diseased bunches. However, discrimination between visually healthy and infected bunches proved to be challenging for a few samples

  18. Xylem structure of four grape varieties and 12 alternative hosts to the xylem-limited bacterium Xylella fastidious

    PubMed Central

    Chatelet, David S.; Wistrom, Christina M.; Purcell, Alexander H.; Rost, Thomas L.; Matthews, Mark A.

    2011-01-01

    Background and Aims The bacterium Xylella fastidiosa (Xf), responsible for Pierce's disease (PD) of grapevine, colonizes the xylem conduits of vines, ultimately killing the plant. However, Vitis vinifera grapevine varieties differ in their susceptibility to Xf and numerous other plant species tolerate Xf populations without showing symptoms. The aim of this study was to examine the xylem structure of grapevines with different susceptibilities to Xf infection, as well as the xylem structure of non-grape plant species that support or limit movement of Xf to determine if anatomical differences might explain some of the differences in susceptibility to Xf. Methods Air and paint were introduced into leaves and stems to examine the connectivity between stem and leaves and the length distribution of their vessels. Leaf petiole and stem anatomies were studied to determine the basis for the free or restricted movement of Xf into the plant. Key Results There were no obvious differences in stem or petiole vascular anatomy among the grape varieties examined, nor among the other plant species that would explain differences in resistance to Xf. Among grape varieties, the more tolerant ‘Sylvaner’ had smaller stem vessel diameters and 20 % more parenchyma rays than the other three varieties. Alternative hosts supporting Xf movement had slightly longer open xylem conduits within leaves, and more connection between stem and leaves, when compared with alternative hosts that limit Xf movement. Conclusions Stem–leaf connectivity via open xylem conduits and vessel length is not responsible for differences in PD tolerance among grape varieties, or for limiting bacterial movement in the tolerant plant species. However, it was found that tolerant host plants had narrower vessels and more parenchyma rays, possibly restricting bacterial movement at the level of the vessels. The implications of xylem structure and connectivity for the means and regulation of bacterial movement are

  19. Identification of novel secreted virulence factors from Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a bacterium that causes Pierce’s disease (PD) of grapevine and other leaf scorch diseases of agriculturally important crops. Little is known about virulence factors that are necessary for X. fastidiosa to grow and cause disease in the xylem vessels of a plant host. Any protein ...

  20. Fatty acid profiling to characterize California strains of Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Different strains of Xylella fastidiosa cause diseases such as Pierce’s disease of grapevine, citrus variegated chlorosis, and bacterial leaf scorch of hardwoods. However, more research is needed to better define subspecies and strains of X. fastidiosa to improve both regulations concerning this bac...

  1. 16D10 siRNAs inhibit root-knot nematode infection in transgenic grape hairy roots

    USDA-ARS?s Scientific Manuscript database

    To develop a biotech-based solution for controlling Root-knot nematodes (RKNs) in grapes, we evaluated the efficacy of plant-derived RNA interference (RNAi) silencing of a conserved RKN effector gene, 16D10, for nematode resistance in transgenic grape hairy roots. Two hairpin-based silencing constru...

  2. α-Ketol linolenic acid (KODA) application affects endogenous abscisic acid, jasmonic acid and aromatic volatiles in grapes infected by a pathogen (Glomerella cingulata).

    PubMed

    Wang, Shanshan; Saito, Takanori; Ohkawa, Katsuya; Ohara, Hitoshi; Shishido, Masahiro; Ikeura, Hiromi; Takagi, Kazuteru; Ogawa, Shigeyuki; Yokoyama, Mineyuki; Kondo, Satoru

    2016-03-15

    Effects of α-ketol linolenic acid (KODA) application on endogenous abscisic acid (ABA), jasmonic acid (JA), and aromatic volatiles were investigated in 'Kyoho' grapes (Vitis labrusca×Vitis vinifera) infected by a pathogen (Glomerella cingulata). The expressions of 9-cis-epoxycarotenoid dioxygenase (VvNCED1), ABA 8'-hydroxylase (VvCYP707A1), lipoxygenase (VvLOX), and allene oxide synthase (VvAOS) were also examined. The grape berries were dipped in 0.1mM KODA solution before inoculation with the pathogen and stored at 25°C for 12 days. The development of infection was significantly suppressed upon KODA treatment. Endogenous ABA, JA and phaseic acid (PA) were induced in inoculated berries. KODA application before inoculation increased endogenous ABA, PA and JA through the activation of VvNCED1, VvCYP707A1 and VvAOS genes, respectively. In addition, terpenes, methyl salicylate (Me-SA) and C6-aldehydes such as (E)-2-hexenal and cis-3-hexenal associated with fungal resistance also increased in KODA-treated berries during storage. These results suggest that the synergistic effect of JA, ABA, and some aromatic volatiles induced by KODA application may provide resistance to pathogen infection in grape berries. Copyright © 2016 Elsevier GmbH. All rights reserved.

  3. Salivary enzymes are injected into xylem by the glassy-winged sharpshooter, a vector of Xylella fastidiosa.

    PubMed

    Backus, Elaine A; Andrews, Kim B; Shugart, Holly J; Carl Greve, L; Labavitch, John M; Alhaddad, Hasan

    2012-07-01

    A few phytophagous hemipteran species such as the glassy-winged sharpshooter, Homalodisca vitripennis, (Germar), subsist entirely on xylem fluid. Although poorly understood, aspects of the insect's salivary physiology may facilitate both xylem-feeding and transmission of plant pathogens. Xylella fastidiosa is a xylem-limited bacterium that causes Pierce's disease of grape and other scorch diseases in many important crops. X. fastidiosa colonizes the anterior foregut (precibarium and cibarium) of H. vitripennis and other xylem-feeding vectors. Bacteria form a dense biofilm anchored in part by an exopolysaccharide (EPS) matrix that is reported to have a β-1,4-glucan backbone. Recently published evidence supports the following, salivation-egestion hypothesis for the inoculation of X. fastidiosa during vector feeding. The insect secretes saliva into the plant and then rapidly takes up a mixture of saliva and plant constituents. During turbulent fluid movements in the precibarium, the bacteria may become mechanically and enzymatically dislodged; the mixture is then egested back out through the stylets into plant cells, possibly including xylem vessels. The present study found that proteins extracted from dissected H. vitripennis salivary glands contain several enzyme activities capable of hydrolyzing glycosidic linkages in polysaccharides such as those found in EPS and plant cell walls, based on current information about the structures of those polysaccharides. One of these enzymes, a β-1,4-endoglucanase (EGase) was enriched in the salivary gland protein extract by subjecting the extract to a few, simple purification steps. The EGase-enriched extract was then used to generate a polyclonal antiserum that was used for immunohistochemical imaging of enzymes in sharpshooter salivary sheaths in grape. Results showed that enzyme-containing gelling saliva is injected into xylem vessels during sharpshooter feeding, in one case being carried by the transpiration stream away

  4. The biology of xylem fluid-feeding insect vectors of Xylella fastidiosa and their relation to disease epidemiology.

    PubMed

    Redak, Richard A; Purcell, Alexander H; Lopes, João R S; Blua, Matthew J; Mizell, Russell F; Andersen, Peter C

    2004-01-01

    Xylophagous leafhopppers are common and abundant insects of tropical and subtropical environments and play important ecological roles in these ecosystems. The feeding biology of these insects is unique in terms of their high feeding rates and a digestive physiology that allows them to assimilate amino acids, organic acids, and sugars at approximately 99% efficiency. For those species well studied, fluctuations in plant xylem chemistry and tension appear to determine the diurnal and seasonal use of their host plants. Relatively few species of xylem fluid-feeding leafhoppers are considered important pests in commercial agriculture, as they transmit the bacterial plant pathogen Xylella fastidiosa. X. fastidiosa induces diseases of grapevines, citrus, coffee, almond, alfalfa, stone fruits, landscape ornamentals, and native hardwoods for which there is no cure. Two Xylella diseases, citrus variegated chlorosis (CVC) and Pierce's disease (PD) of grapevines, have emerged as important issues within the past decade. In Brazil, CVC became important in the early 1990s and has now expanded throughout many citrus-growing areas of South America and threatens to spread to North America. The recent establishment of the exotic glassy-winged sharpshooter (Homalodisca coagulata) in California now threatens much of the United States' wine grape, table grape, and almond production. The spread of H. coagulata throughout southern California and the spread of CVC northward from Argentina through Brazil exemplifies the biological risks from exotic species. The occurrence and epidemiology of leafhopper-vectored Xylella diseases are discussed.

  5. Environmental Conditions Affect Botrytis cinerea Infection of Mature Grape Berries More Than the Strain or Transposon Genotype.

    PubMed

    Ciliberti, Nicola; Fermaud, Marc; Roudet, Jean; Rossi, Vittorio

    2015-08-01

    Effects of environment, Botrytis cinerea strain, and their interaction on the infection of mature grape berries were investigated. The combined effect of temperature (T) of 15, 20, 25, and 30°C and relative humidity (RH) of 65, 80, 90, and 100% was studied by inoculating berries with mycelium plugs. Regardless of the T, no disease occurred at 65% RH, and both disease incidence and severity increased with increasing RH. The combined effect of T (5 to 30°C) and wetness duration (WD) of 3, 6, 12, 24, and 36 h was studied by inoculating berries with conidia. At WD of 36 h, disease incidence was approximately 75% of affected berries at 20 or 25°C, 50% at 15°C, and 30 to 20% at 30 and 10°C; no infection occurred at 5°C. Under favorable conditions (100% RH or 36 h of WD) and unfavorable conditions (65% RH or 3 h of WD), berry wounding did not significantly affect disease incidence; under moderately favorable conditions (80% RH or 6 to 12 h of WD), disease incidence was approximately 1.5 to 5 times higher in wounded than in intact berries. Our data collectively showed that (i) T and RH or WD were more important than strain for mature berry infection by either mycelium or conidia and (ii) the effect of the environment on the different strains was similar. Two equations were developed describing the combined effect of T and RH, or T and WD, on disease incidence following inoculation by mycelium (R2=0.99) or conidia (R2=0.96), respectively. These equations may be useful in the development of models used to predict and control Botrytis bunch rot during berry ripening.

  6. Population Structure of the Bacterial Pathogen Xylella fastidiosa among Street Trees in Washington D.C.

    PubMed Central

    Harris, Jordan Lee; Balci, Yilmaz

    2015-01-01

    Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship. PMID:25815838

  7. Population structure of the bacterial pathogen Xylella fastidiosa among street trees in Washington D.C.

    PubMed

    Harris, Jordan Lee; Balci, Yilmaz

    2015-01-01

    Bacterial leaf scorch, associated with the bacterial pathogen Xylella fastidiosa, is a widely established and problematic disease of landscape ornamentals in Washington D.C. A multi-locus sequence typing analysis was performed using 10 housekeeping loci for X. fastidiosa strains in order to better understand the epidemiology of leaf scorch disease in this municipal environment. Samples were collected from 7 different tree species located throughout the District of Columbia, consisting of 101 samples of symptomatic and asymptomatic foliage from 84 different trees. Five strains of the bacteria were identified. Consistent with prior data, these strains were host specific, with only one strain associated with members of the red oak family, one strain associated with American elm, one strain associated with American sycamore, and two strains associated with mulberry. Strains found for asymptomatic foliage were the same as strains from the symptomatic foliage on individual trees. Cross transmission of the strains was not observed at sites with multiple species of infected trees within an approx. 25 m radius of one another. X. fastidiosa strain specificity observed for each genus of tree suggests a highly specialized host-pathogen relationship.

  8. Homologous Recombination and Xylella fastidiosa Host-Pathogen Associations in South America.

    PubMed

    Coletta-Filho, Helvécio D; Francisco, Carolina S; Lopes, João R S; Muller, Christiane; Almeida, Rodrigo P P

    2017-03-01

    Homologous recombination affects the evolution of bacteria such as Xylella fastidiosa, a naturally competent plant pathogen that requires insect vectors for dispersal. This bacterial species is taxonomically divided into subspecies, with phylogenetic clusters within subspecies that are host specific. One subspecies, pauca, is primarily limited to South America, with the exception of recently reported strains in Europe and Costa Rica. Despite the economic importance of X. fastidiosa subsp. pauca in South America, little is known about its genetic diversity. Multilocus sequence typing (MLST) has previously identified six sequence types (ST) among plant samples collected in Brazil (both subsp. pauca and multiplex). Here, we report on a survey of X. fastidiosa genetic diversity (MLST based) performed in six regions in Brazil and two in Argentina, by sampling five different plant species. In addition to the six previously reported ST, seven new subsp. pauca and two new subsp. multiplex ST were identified. The presence of subsp. multiplex in South America is considered to be the consequence of a single introduction from its native range in North America more than 80 years ago. Different phylogenetic approaches clustered the South American ST into four groups, with strains infecting citrus (subsp. pauca); coffee and olive (subsp. pauca); coffee, hibiscus, and plum (subsp. pauca); and plum (subsp. multiplex). In areas where these different genetic clusters occurred sympatrically, we found evidence of homologous recombination in the form of bidirectional allelic exchange between subspp. pauca and multiplex. In fact, the only strain of subsp. pauca isolated from a plum host had an allele that originated from subsp. multiplex. These signatures of bidirectional homologous recombination between endemic and introduced ST indicate that gene flow occurs in short evolutionary time frames in X. fastidiosa, despite the ecological isolation (i.e., host plant species) of genotypes.

  9. Isolation and molecular characterization of Xylella fastidiosa from coffee plants in Costa Rica.

    PubMed

    Montero-Astúa, Mauricio; Chacón-Díaz, Carlos; Aguilar, Estela; Rodríguez, Carlos Mario; Garita, Laura; Villalobos, William; Moreira, Lisela; Hartung, John S; Rivera, Carmen

    2008-10-01

    Coffee plants exhibiting a range of symptoms including mild to severe curling of leaf margins, chlorosis and deformation of leaves, stunting of plants, shortening of internodes, and dieback of branches have been reported since 1995 in several regions of Costa Rica's Central Valley. The symptoms are referred to by coffee producers in Costa Rica as "crespera" disease and have been associated with the presence of the bacterium Xylella fastidiosa. Coffee plants determined to be infected by the bacterium by enzyme linked immunosorbent assay (ELISA), were used for both transmission electron microscopy (TEM) and for isolation of the bacterium in PW broth or agar. Petioles examined by TEM contained rod-shaped bacteria inside the xylem vessels. The bacteria measured 0.3 to 0.5 microm in width and 1.5 to 3.0 microm in length, and had rippled cell walls 10 to 40 nm in thickness, typical of X. fastidiosa. Small, circular, dome-shaped colonies were observed 7 to 26 days after plating of plant extracts on PW agar. The colonies were comprised of Gram-negative rods of variable length and a characteristic slight longitudinal bending. TEM of the isolated bacteria showed characteristic rippled cell walls, similar to those observed in plant tissue. ELISA and PCR with specific primer pairs 272-l-int/272-2-int and RST31/RST33 confirmed the identity of the isolated bacteria as X. fastidiosa. RFLP analysis of the amplification products revealed diversity within X. fastidiosa strains from Costa Rica and suggest closer genetic proximity to strains from the United States of America than to other coffee or citrus strains from Brazil.

  10. Grape Expectations.

    ERIC Educational Resources Information Center

    Rye, James A.

    1997-01-01

    Details an investigation concerned with the composition of a grape to illustrate how food and nutrition topics can drive inquiry-oriented science learning. Students design experiments that surround the development of a fictitious new beverage. (DDR)

  11. Grape Expectations.

    ERIC Educational Resources Information Center

    Rye, James A.

    1997-01-01

    Details an investigation concerned with the composition of a grape to illustrate how food and nutrition topics can drive inquiry-oriented science learning. Students design experiments that surround the development of a fictitious new beverage. (DDR)

  12. Functional and Evolutionary Characterization of a UDP-Xylose Synthase Gene from the Plant Pathogen Xylella fastidiosa, Involved in the Synthesis of Bacterial Lipopolysaccharide.

    PubMed

    Alencar, Valquíria Campos; Jabes, Daniela Leite; Menegidio, Fabiano Bezerra; Sassaki, Guilherme Lanzi; de Souza, Lucas Rodrigo; Puzer, Luciano; Meneghetti, Maria Cecília Zorél; Lima, Marcelo Andrade; Tersariol, Ivarne Luis Dos Santos; de Oliveira, Regina Costa; Nunes, Luiz R

    2017-02-07

    Xylella fastidiosa is a plant-infecting bacillus, responsible for many important crop diseases, such as Pierce's disease of vineyards, citrus variegated chlorosis, and coffee leaf scorch (CLS), among others. Recent genomic comparisons involving two CLS-related strains, belonging to X. fastidiosa subsp. pauca, revealed that one of them carries a frameshift mutation that inactivates a gene encoding an oxidoreductase of the short-chain dehydrogenase/reductase (SDR) superfamily, which may play important roles in determining structural variations in bacterial glycans and glycoconjugates. However, the exact nature of this SDR has been a matter of controversy, as different annotations of X. fastidiosa genomes have implicated it in distinct reactions. To confirm the nature of this mutated SDR, a comparative analysis was initially performed, suggesting that it belongs to a subgroup of SDR decarboxylases, representing a UDP-xylose synthase (Uxs). Functional assays, using a recombinant derivative of this enzyme, confirmed its nature as XfUxs, and carbohydrate composition analyses, performed with lipopolysaccharide (LPS) molecules obtained from different strains, indicate that inactivation of the X. fastidiosa uxs gene affects the LPS structure among CLS-related X. fastidiosa strains. Finally, a comparative sequence analysis suggests that this mutation is likely to result in a morphological and evolutionary hallmark that differentiates two subgroups of CLS-related strains, which may influence interactions between these bacteria and their plant and/or insect hosts.

  13. Chitin utilization by the insect-transmitted bacterium Xylella fastidiosa.

    PubMed

    Killiny, Nabil; Prado, Simone S; Almeida, Rodrigo P P

    2010-09-01

    Xylella fastidiosa is an insect-borne bacterium that colonizes xylem vessels of a large number of host plants, including several crops of economic importance. Chitin is a polysaccharide present in the cuticle of leafhopper vectors of X. fastidiosa and may serve as a carbon source for this bacterium. Biological assays showed that X. fastidiosa reached larger populations in the presence of chitin. Additionally, chitin induced phenotypic changes in this bacterium, notably increasing adhesiveness. Quantitative PCR assays indicated transcriptional changes in the presence of chitin, and an enzymatic assay demonstrated chitinolytic activity by X. fastidiosa. An ortholog of the chitinase A gene (chiA) was identified in the X. fastidiosa genome. The in silico analysis revealed that the open reading frame of chiA encodes a protein of 351 amino acids with an estimated molecular mass of 40 kDa. chiA is in a locus that consists of genes implicated in polysaccharide degradation. Moreover, this locus was also found in the genomes of closely related bacteria in the genus Xanthomonas, which are plant but not insect associated. X. fastidiosa degraded chitin when grown on a solid chitin-yeast extract-agar medium and grew in liquid medium with chitin as the sole carbon source; ChiA was also determined to be secreted. The gene encoding ChiA was cloned into Escherichia coli, and endochitinase activity was detected in the transformant, showing that the gene is functional and involved in chitin degradation. The results suggest that X. fastidiosa may use its vectors' foregut surface as a carbon source. In addition, chitin may trigger X. fastidiosa's gene regulation and biofilm formation within vectors. Further work is necessary to characterize the role of chitin and its utilization in X. fastidiosa.

  14. Production of the phytoalexins trans-resveratrol and delta-viniferin in two economy-relevant grape cultivars upon infection with Botrytis cinerea in field conditions.

    PubMed

    Timperio, Anna Maria; D'Alessandro, Angelo; Fagioni, Marco; Magro, Paolo; Zolla, Lello

    2012-01-01

    Leaves, shoots and flowers from two different economy-relevant grape cultivars, Merlot and Cabernet Sauvignon, were examined to assess the distribution of phytoalexins upon inoculation with Botrytis cinerea at pre-bloom, bloom, and post-bloom stages. Mass spectrometric analysis evidenced considerable levels of trans-resveratrol (3,5,4'-trihydroxystilbene), albeit higher in Cabernet Sauvignon, in leaves from both grape cultivars following fungal infection at all the examined stages of development. Although both these cultivars are reported to be sensitive against fungal infections, in Cabernet Sauvignon leaves and flowers, we were also able to measure relevant quantities of the resveratrol dehydrodimer delta-viniferin. While infection by B. cinerea occurs at bloom stage, high-sensitivity of the HPLC-mass spectrometric analytic method allowed detecting measurable levels of viniferins even in early pre-bloom stages in Cabernet Sauvignon flowers and to evidence even slight resveratrol differences between the cultivars. Concordingly, Cabernet Sauvignon better responded to fungal infection. This analysis allowed us to conclude that, even when analyzing fungal infection-sensitive cultivars, the HPLC-MS method holds the sensitivity to highlight the slightest differences in the concentrations of the two phytoalexins and correlate them to different anti-fungal response potential. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  15. Development and systematic validation of qPCR assays for rapid and reliable differentiation of Xylella fastidiosa strains causing citrus variegated chlorosis.

    PubMed

    Li, Wenbin; Teixeira, Diva C; Hartung, John S; Huang, Qi; Duan, Yongping; Zhou, Lijuan; Chen, Jianchi; Lin, Hong; Lopes, Silvio; Ayres, A Juliano; Levy, Laurene

    2013-01-01

    The xylem-limited, Gram-negative, fastidious plant bacterium Xylella fastidiosa is the causal agent of citrus variegated chlorosis (CVC), a destructive disease affecting approximately half of the citrus plantations in the State of São Paulo, Brazil. The disease was recently found in Central America and is threatening the multi-billion U.S. citrus industry. Many strains of X. fastidiosa are pathogens or endophytes in various plants growing in the U.S., and some strains cross infect several host plants. In this study, a TaqMan-based assay targeting the 16S rDNA signature region was developed for the identification of X. fastidiosa at the species level. Another TaqMan-based assay was developed for the specific identification of the CVC strains. Both new assays have been systematically validated in comparison with the primer/probe sets from four previously published assays on one platform and under similar PCR conditions, and shown to be superior. The species specific assay detected all X. fastidiosa strains and did not amplify any other citrus pathogen or endophyte tested. The CVC-specific assay detected all CVC strains but did not amplify any non-CVC X. fastidiosa nor any other citrus pathogen or endophyte evaluated. Both sets were multiplexed with a reliable internal control assay targeting host plant DNA, and their diagnostic specificity and sensitivity remained unchanged. This internal control provides quality assurance for DNA extraction, performance of PCR reagents, platforms and operators. The limit of detection for both assays was equivalent to 2 to 10 cells of X. fastidiosa per reaction for field citrus samples. Petioles and midribs of symptomatic leaves of sweet orange harbored the highest populations of X. fastidiosa, providing the best materials for detection of the pathogen. These new species specific assay will be invaluable for molecular identification of X. fastidiosa at the species level, and the CVC specific assay will be very powerful for the

  16. Factors affecting the initial adhesion and retention of the plant pathogen Xylella fastidiosa in the foregut of an insect vector.

    PubMed

    Killiny, Nabil; Almeida, Rodrigo P P

    2014-01-01

    Vector transmission of bacterial plant pathogens involves three steps: pathogen acquisition from an infected host, retention within the vector, and inoculation of cells into susceptible tissue of an uninfected plant. In this study, a combination of plant and artificial diet systems were used to determine the importance of several genes on the initial adhesion and retention of the bacterium Xylella fastidiosa to an efficient insect vector. Mutant strains included fimbrial (fimA and pilB) and afimbrial (hxfA and hxfB) adhesins and three loci involved in regulatory systems (rpfF, rpfC, and cgsA). Transmission assays with variable retention time indicated that HxfA and HxfB were primarily important for early adhesion to vectors, while FimA was necessary for both adhesion and retention. The long pilus protein PilB was not deficient in initial adhesion but may be important for retention. Genes upregulated under the control of rpfF are important for both initial adhesion and retention, as transmission rates of this mutant strain were initially low and decreased over time, while disruption of rpfC and cgsA yielded trends similar to that shown by the wild-type control. Because induction of an X. fastidiosa transmissible state requires pectin, a series of experiments were used to test the roles of a polygalacturonase (pglA) and the pectin and galacturonic acid carbohydrates on the transmission of X. fastidiosa. Results show that galacturonic acid, or PglA activity breaking pectin into its major subunit (galacturonic acid), is required for X. fastidiosa vector transmission using an artificial diet system. This study shows that early adhesion and retention of X. fastidiosa are mediated by different factors. It also illustrates that the interpretation of results of vector transmission experiments, in the context of vector-pathogen interaction studies, is highly dependent on experimental design.

  17. Real-time investigation of mannosyltransferase function of a Xylella fastidiosa recombinant GumH protein using QCM-D.

    PubMed

    Alves, Claudia A; Pedroso, Mariele M; de Moraes, Marcela C; Souza, Dulce H F; Cass, Quezia B; Faria, Ronaldo C

    2011-05-20

    Xylella fastidiosa is a gram-negative bacterium that causes serious diseases in economically important crops, including grapevine, coffee, and citrus fruits. X. fastidiosa colonizes the xylem vessels of the infected plants, thereby blocking water and nutrient transport. The genome sequence of X. fastidiosa has revealed an operon containing nine genes possibly involved in the synthesis of an exopolisaccharide (EPS) named fastidian gum that can be related with the pathogenicity of this bacterium. The α-1,3-mannosyltransferase (GumH) enzyme from X. fastidiosa is involved in fastidian gum production. GumH is responsible for the transfer of mannose from guanosine diphosphate mannose (GDP-man) to the cellobiose-pyrophosphate-polyprenol carrier lipid (CPP-Lip) during the assembly and biosynthesis of EPS. In this work, a method for real-time detection of recombinant GumH enzymatic activity was successfully developed using a Quartz Crystal Microbalance with dissipation monitoring (QCM-D). The QCM-D transducer was strategically modified with CPP-Lip by using a solid-supported lipid bilayer that makes use of a self-assembled monolayer of 1-undecanethiol. Monitoring the real-time CPP-Lip QCM-D transducer in the presence of GDP-man and GumH enzyme shows a mass increase, indicating the transfer of mannose. The real-time QCM-D determination of mannosyltransferase function was validated by a High Performance Liquid Chromatography (LC) method developed for determination of GDP produced by enzymatic reaction. LC results confirmed the activity of recombinant GumH protein, which is the first enzyme involved in the biosynthesis of the EPS from X. fastidiosa enzymatically characterized.

  18. Xylella fastidiosa CoDiRO strain associated with the olive quick decline syndrome in southern Italy belongs to a clonal complex of the subspecies pauca that evolved in Central America.

    PubMed

    Marcelletti, Simone; Scortichini, Marco

    2016-12-01

    Xylella fastidiosa, a xylem-limited bacterium transmitted by xylem-fluid-feeding Hemiptera insects, causes economic losses of both woody and herbaceous plant species. A Xyl. fastidiosa subsp. pauca strain, namely CoDiRO, was recently found to be associated with the 'olive quick decline syndrome' in southern Italy (i.e. Apulia region). Recently, some Xyl. fastidiosa strains intercepted in France from Coffea spp. plant cuttings imported from Central and South America were characterized. The introduction of infected plant material from Central America in Apulia was also postulated even though an ad hoc study to confirm this hypothesis is lacking. In the present study, we assessed the complete and draft genome of 27 Xyl. fastidiosa strains. Through a genome-wide approach, we confirmed the occurrence of three subspecies within Xyl. fastidiosa, namely fastidiosa, multiplex and pauca, and demonstrated the occurrence of a genetic clonal complex of four Xyl. fastidiosa strains belonging to subspecies pauca which evolved in Central America. The CoDiRO strain displayed 13 SNPs when compared with a strain isolated in Costa Rica from Coffea sp. and 32 SNPs when compared with two strains obtained from Nerium oleander in Costa Rica. These results support the close relationships of the two strains. The four strains in the clonal complex contain prophage-like genes in their genomes. This study strongly supports the possibility of the introduction of Xyl. fastidiosa in southern Italy via coffee plants grown in Central America. The data also stress how the current global circulation of agricultural commodities potentially threatens the agrosystems worldwide.

  19. Phenology of Xylella fastidiosa and Draeculocephala minerva in California almond nurseries: an assessment of plant vulnerability to almond leaf scorch disease

    USDA-ARS?s Scientific Manuscript database

    Management of a plant disease requires knowledge of all possible infection pathways. Almond leaf scorch disease (ALSD) is caused by the xylem-limited bacterium Xylella fastidiosa, which is transmitted by several species of leafhoppers. The objectives of this research were to elucidate the fate of b...

  20. Phenology of Xylella fastidiosa and its vector around California almond nurseries: An assessment of plant vulnerability to almond leaf scorch disease

    USDA-ARS?s Scientific Manuscript database

    Management of almond leaf scorch disease requires knowledge of all possible infection pathways. The disease is caused by the xylem-limited bacterium Xylella fastidiosa, which is transmitted by several species of leafhoppers. The objectives of this research were to elucidate the fate of bacteria in p...

  1. Localization and characterization of Xylella fastidiosa haemagglutinin adhesins.

    PubMed

    Voegel, Tanja M; Warren, Jeremy G; Matsumoto, Ayumi; Igo, Michele M; Kirkpatrick, Bruce C

    2010-07-01

    Xylella fastidiosa is a gram-negative, xylem-inhabiting, plant-pathogenic bacterium responsible for several important diseases including Pierce's disease (PD) of grapevines. The bacteria form biofilms in grapevine xylem that contribute to the occlusion of the xylem vessels. X. fastidiosa haemagglutinin (HA) proteins are large afimbrial adhesins that have been shown to be crucial for biofilm formation. Little is known about the mechanism of X. fastidiosa HA-mediated cell-cell aggregation or the localization of the adhesins on the cell. We generated anti-HA antibodies and show that X. fastidiosa HAs are present in the outer membrane and secreted both as soluble proteins and in membrane vesicles. Furthermore, the HA pre-proteins are processed from the predicted molecular mass of 360 kDa to a mature 220 kDa protein. Based on this information, we are evaluating a novel form of potential resistance against PD by generating HA-expressing transgenic grapevines.

  2. Characterization of different Californian strains of Xylella fastidiosa by fatty acid methyl ester (FAME) analyses

    USDA-ARS?s Scientific Manuscript database

    Detection and characterization of different subspecies of Xylella fastidiosa are often dependent upon genotyping. However, complementary methods to detect and characterize different X. fastidiosa strains based on phenotype are needed to confirm conclusions. Characterization of the composition of fat...

  3. Characterization of a Diffusible Signaling Factor from Xylella fastidiosa

    PubMed Central

    Beaulieu, Ellen D.; Ionescu, Michael; Chatterjee, Subhadeep; Yokota, Kenji; Trauner, Dirk; Lindow, Steven

    2013-01-01

    ABSTRACT Cell-cell signaling in Xylella fastidiosa has been implicated in the coordination of traits enabling colonization in plant hosts as well as insect vectors. This cell density-dependent signaling has been attributed to a diffusible signaling factor (DSF) produced by the DSF synthase RpfF. DSF produced by related bacterial species are unsaturated fatty acids, but that of X. fastidiosa was thought to be different from those of other taxa. We describe here the isolation and characterization of an X. fastidiosa DSF (XfDSF) as 2(Z)-tetradecenoic acid. This compound was isolated both from recombinant Erwinia herbicola expressing X. fastidiosa rpfF and from an X. fastidiosa rpfC deletion mutant that overproduces DSF. Since an rpfF mutant is impaired in biofilm formation and underexpresses the hemagglutinin-like protein-encoding genes hxfA and hxfB, we demonstrate that these traits can be restored by ca. 0.5 µM XfDSF but not by myristic acid, the fully saturated tetradecenoic acid. A phoA-based X. fastidiosa biosensor that assesses DSF-dependent expression of hxfA or hxfB revealed a high level of molecular specificity of DSF signaling. PMID:23300249

  4. Genome-Wide Analysis Provides Evidence on the Genetic Relatedness of the Emergent Xylella fastidiosa Genotype in Italy to Isolates from Central America.

    PubMed

    Giampetruzzi, Annalisa; Saponari, Maria; Loconsole, Giuliana; Boscia, Donato; Savino, Vito Nicola; Almeida, Rodrigo P P; Zicca, Stefania; Landa, Blanca B; Chacón-Diaz, Carlos; Saldarelli, Pasquale

    2017-07-01

    Xylella fastidiosa is a plant-pathogenic bacterium recently introduced in Europe that is causing decline in olive trees in the South of Italy. Genetic studies have consistently shown that the bacterial genotype recovered from infected olive trees belongs to the sequence type ST53 within subspecies pauca. This genotype, ST53, has also been reported to occur in Costa Rica. The ancestry of ST53 was recently clarified, showing it contains alleles that are monophyletic with those of subsp. pauca in South America. To more robustly determine the phylogenetic placement of ST53 within X. fastidiosa, we performed a comparative analysis based on single nucleotide polymorphisms (SNPs) and the study of the pan-genome of the 27 currently public available whole genome sequences of X. fastidiosa. The resulting maximum-parsimony and maximum likelihood trees constructed using the SNPs and the pan-genome analysis are consistent with previously described X. fastidiosa taxonomy, distinguishing the subsp. fastidiosa, multiplex, pauca, sandyi, and morus. Within the subsp. pauca, the Italian and three Costa Rican isolates, all belonging to ST53, formed a compact phylotype in a clade divergent from the South American pauca isolates, also distinct from the recently described coffee isolate CFBP8072 imported into Europe from Ecuador. These findings were also supported by the gene characterization of a conjugative plasmid shared by all the four ST53 isolates. Furthermore, isolates of the ST53 clade possess an exclusive locus encoding a putative ATP-binding protein belonging to the family of histidine kinase-like ATPase gene, which is not present in isolates from the subspecies multiplex, sandyi, and pauca, but was detected in ST21 isolates of the subspecies fastidiosa from Costa Rica. The clustering and distinctiveness of the ST53 isolates supports the hypothesis of their common origin, and the limited genetic diversity among these isolates suggests this is an emerging clade within subsp

  5. Plant water stress effects on stylet probing behaviors of Homalodisca vitripennis (Hemiptera: Cicadellidae) associated with acquisition and inoculation of the bacterium Xylella fastidiosa.

    PubMed

    Krugner, Rodrigo; Backus, Elaine A

    2014-02-01

    ABSTRACT The glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), is a xylem fluid-ingesting leafhopper that transmits Xylella fastidiosa Wells et al., a plant-infecting bacterium that causes several plant diseases in the Americas. Although the role of plant water stress on the population density and dispersal ofH. vitripennis has been studied, nothing is known about the effects of plant water stress on the transmission of X. fastidiosa by H. vitripennis. A laboratory study was conducted to determine the influence of plant water stress on the sharpshooter stylet probing behaviors associated with the acquisition and inoculation of X. fastidiosa. Electrical penetration graph was used to monitor H. vitripennis feeding behaviors for 20-h periods on citrus [Citrus sinensis (L.) Osbeck] and almond [Prunus dulcis (Miller) D.A. Webb] plants subjected to levels of water stress. Adult H. vitripennis successfully located xylem vessels, then performed behaviors related to the evaluation of the xylem cell and fluid, and finally ingested xylem fluid from citrus and almond plants under the tested fluid tensions ranging from -5.5 to -33.0 bars and -6.0 to -24.5 bars, respectively. In general, long and frequent feeding events associated with the acquisition and inoculation of X. fastidiosa were observed only in fully irrigated plants (i.e., >-10 bars), which suggests that even low levels of plant water stress may reduce the spread of X. fastidiosa. Results provided insights to disease epidemiology and support the hypothesis that application of regulated deficit irrigation has the potential to reduce the incidence of diseases caused by X.fastidiosa by reducing the number of vectors and by decreasing pathogen transmission efficiency.

  6. Proteome Biomarkers in Xylem Reveal Pierce's Disease Tolerance in Grape.

    PubMed

    Katam, Ramesh; Chibanguza, Kundai; Latinwo, Lekan M; Smith, Danyel

    Pierce's disease (PD) is a significant threat to grape cultivation and industry. The disease caused by bacterium Xylella fastidiosa clogs xylem vessels resulting in wilting of the plant. PD-tolerant grape genotypes are believed to produce certain novel components in xylem tissue that help them to combat invading pathogens. Research has been aimed at characterizing the uniquely expressed xylem proteins by PD-tolerant genotypes. The objectives were to i) compare and characterize Vitis xylem proteins differentially expressed in PD-tolerant and PD-susceptible cultivars and, ii) identify xylem proteins uniquely expressed in PD-tolerant genotypes. A high throughput two-dimensional gel electrophoresis of xylem proteins from three Vitis species identified more than 200 proteins with pls 3.0 to 9.0 and molecular weights of 20 to 75 kDa. The differentially expressed proteins were then excised and analyzed with MALDI/TOF mass spectrometer. The mass spectra were collected and protein identification was performed against the Viridiplantae database using Matrix Science algorithm. Proteins were mapped to the universal protein resource to study gene ontology. Comparative analysis of the xylem proteome of three species indicated the highest number of proteins in muscadine grape, followed by Florida hybrid bunch and bunch grape. These proteins were all associated with disease resistance, energy metabolism, protein processing and degradation, biosynthesis, stress related functions, cell wall biogenesis, signal transduction, and ROS detoxification. Furthermore, β-1, 3-glucanase, 10-deacetyl baccatin III-10-O-acetyl transferase-like, COP9, and aspartyl protease nepenthesin precursor proteins were found to be uniquely expressed in PD-tolerant muscadine grape, while they are absent in PD-susceptible bunch grape. Data suggests that muscadine and Florida hybrid bunch grapes express novel proteins in xylem to overcome pathogen attack while bunch grape lacks this capability, making them

  7. Morphological and molecular investigations of a microsporidium infecting the European grape vine moth, Lobesia botrana Den. et Schiff., and its taxonomic determination as Cystosporogenes legeri nov. comb.

    PubMed

    Kleespies, Regina G; Vossbrinck, Charles R; Lange, Martin; Jehle, Johannes A

    2003-07-01

    We have isolated a microsporidium from a laboratory stock of the European grape vine moth, Lobesia botrana Den. et Schiff. (Lepidoptera, Tortricidae). Screening of this stock showed an infection rate of more than 90%, whereas field collected larvae from three different locations in Rhineland-Palatinate (Germany) did not demonstrate any signs of infection. Light and electron microscopic investigations of infected insects showed that gross pathology, morphology, and ultrastructure of the microsporidium are similar to those described earlier for Pleistophora legeri. Comparative phylogenetic analysis of the small subunit rDNA using maximum likelihood, maximum parsimony, and neighbour joining distance methods showed that our isolate was closely related to Cystosporogenes operophterae. Based on our morphological and molecular investigations we propose to rename this species Cystosporogenes legeri nov. comb.

  8. Molecular characterization and impacts of a strain of Grapevine leafroll-associated virus 2 causing asymptomatic infection in a wine grape cultivar

    PubMed Central

    2013-01-01

    Background Grapevine leafroll (GLD) is considered as the most economically important virus disease affecting wine grapes (Vitis vinifera L.) in many grapevine-growing regions. GLD produces distinct symptoms in red- and white-berried cultivars. In this study, we determined the complete genome sequence of an asymptomatic strain of Grapevine leafroll-associated virus 2 (GLRaV-2) and studied its impacts on fruit yield and berry quality attributes in an own-rooted, red-berried wine grape cultivar. Findings The complete genome of GLRaV-2 obtained from a red-berried wine grape cultivar Sangiovese, designated as GLRaV-2-SG, was determined to be 16,474 nucleotides in length. In pairwise comparisons, using complete genome sequences of GLRaV-2 strains available in GenBank, GLRaV-2-SG was more closely related to GLRaV-2-OR1 from Oregon, USA, and GLRaV-2-93/955 from South Africa, and distantly related to GLRaV-2-BD from Italy and GLRaV-2-RG from USA. Fruit yield estimates and berry quality analysis at the time of commercial harvest indicated that GLRaV-2-SG had little impact on fruit yield and total soluble solids, juice pH and total anthocyanins of berry skin. Conclusions Because so little is known about the effects of asymptomatic virus infections in wine grapes, this study expanded our knowledge of the occurrence and impacts of GLRaV-2 causing asymptomatic infections. Our results indicated that an asymptomatic strain of GLRaV-2 may not cause significant effects to overall fruit yield and berry quality in own-rooted vines, but can affect its host in more subtle ways. Since disease symptoms are not apparent, relying on visual symptoms during disease surveys may result in the escape of asymptomatic strains of GLRaV-2. Thus, it is necessary to use appropriate diagnostic assays for reliable detection of viruses causing asymptomatic infections. PMID:24171725

  9. Molecular Characteristics and Efficacy of 16D10 siRNAs in Inhibiting Root-Knot Nematode Infection in Transgenic Grape Hairy Roots

    PubMed Central

    Chronis, Demosthenis; Wang, Xiaohong; Cousins, Peter; Zhong, Gan-Yuan

    2013-01-01

    Root-knot nematodes (RKNs) infect many annual and perennial crops and are the most devastating soil-born pests in vineyards. To develop a biotech-based solution for controlling RKNs in grapes, we evaluated the efficacy of plant-derived RNA interference (RNAi) silencing of a conserved RKN effector gene, 16D10, for nematode resistance in transgenic grape hairy roots. Two hairpin-based silencing constructs, containing a stem sequence of 42 bp (pART27-42) or 271 bp (pART27-271) of the 16D10 gene, were transformed into grape hairy roots and compared for their small interfering RNA (siRNA) production and efficacy on suppression of nematode infection. Transgenic hairy root lines carrying either of the two RNAi constructs showed less susceptibility to nematode infection compared with control. Small RNA libraries from four pART27-42 and two pART27-271 hairy root lines were sequenced using an Illumina sequencing technology. The pART27-42 lines produced hundred times more 16D10-specific siRNAs than the pART27-271 lines. On average the 16D10 siRNA population had higher GC content than the 16D10 stem sequences in the RNAi constructs, supporting previous observation that plant dicer-like enzymes prefer GC-rich sequences as substrates for siRNA production. The stems of the 16D10 RNAi constructs were not equally processed into siRNAs. Several hot spots for siRNA production were found in similar positions of the hairpin stems in pART27-42 and pART27-271. Interestingly, stem sequences at the loop terminus produced more siRNAs than those at the stem base. Furthermore, the relative abundance of guide and passenger single-stranded RNAs from putative siRNA duplexes was largely correlated with their 5′ end thermodynamic strength. This study demonstrated the feasibility of using a plant-derived RNAi approach for generation of novel nematode resistance in grapes and revealed several interesting molecular characteristics of transgene siRNAs important for optimizing plant RNAi constructs

  10. Molecular characteristics and efficacy of 16D10 siRNAs in inhibiting root-knot nematode infection in transgenic grape hairy roots.

    PubMed

    Yang, Yingzhen; Jittayasothorn, Yingyos; Chronis, Demosthenis; Wang, Xiaohong; Cousins, Peter; Zhong, Gan-Yuan

    2013-01-01

    Root-knot nematodes (RKNs) infect many annual and perennial crops and are the most devastating soil-born pests in vineyards. To develop a biotech-based solution for controlling RKNs in grapes, we evaluated the efficacy of plant-derived RNA interference (RNAi) silencing of a conserved RKN effector gene, 16D10, for nematode resistance in transgenic grape hairy roots. Two hairpin-based silencing constructs, containing a stem sequence of 42 bp (pART27-42) or 271 bp (pART27-271) of the 16D10 gene, were transformed into grape hairy roots and compared for their small interfering RNA (siRNA) production and efficacy on suppression of nematode infection. Transgenic hairy root lines carrying either of the two RNAi constructs showed less susceptibility to nematode infection compared with control. Small RNA libraries from four pART27-42 and two pART27-271 hairy root lines were sequenced using an Illumina sequencing technology. The pART27-42 lines produced hundred times more 16D10-specific siRNAs than the pART27-271 lines. On average the 16D10 siRNA population had higher GC content than the 16D10 stem sequences in the RNAi constructs, supporting previous observation that plant dicer-like enzymes prefer GC-rich sequences as substrates for siRNA production. The stems of the 16D10 RNAi constructs were not equally processed into siRNAs. Several hot spots for siRNA production were found in similar positions of the hairpin stems in pART27-42 and pART27-271. Interestingly, stem sequences at the loop terminus produced more siRNAs than those at the stem base. Furthermore, the relative abundance of guide and passenger single-stranded RNAs from putative siRNA duplexes was largely correlated with their 5' end thermodynamic strength. This study demonstrated the feasibility of using a plant-derived RNAi approach for generation of novel nematode resistance in grapes and revealed several interesting molecular characteristics of transgene siRNAs important for optimizing plant RNAi constructs.

  11. Grape Seed Extract

    MedlinePlus

    ... grape seed Latin Name: Vitis vinifera Background Since ancient Greece people have used grapes, grape leaves, and ... 8):1173-1181. Fine AM. Oligomeric proanthocyanidin complexes: history, structure, and phytopharmaceutical applications. Alternative Medicine Review. 2000; ...

  12. Surface physicochemical properties at the micro and nano length scales: role on bacterial adhesion and Xylella fastidiosa biofilm development.

    PubMed

    Lorite, Gabriela S; Janissen, Richard; Clerici, João H; Rodrigues, Carolina M; Tomaz, Juarez P; Mizaikoff, Boris; Kranz, Christine; de Souza, Alessandra A; Cotta, Mônica A

    2013-01-01

    The phytopathogen Xylella fastidiosa grows as a biofilm causing vascular occlusion and consequently nutrient and water stress in different plant hosts by adhesion on xylem vessel surfaces composed of cellulose, hemicellulose, pectin and proteins. Understanding the factors which influence bacterial adhesion and biofilm development is a key issue in identifying mechanisms for preventing biofilm formation in infected plants. In this study, we show that X. fastidiosa biofilm development and architecture correlate well with physicochemical surface properties after interaction with the culture medium. Different biotic and abiotic substrates such as silicon (Si) and derivatized cellulose films were studied. Both biofilms and substrates were characterized at the micro- and nanoscale, which corresponds to the actual bacterial cell and membrane/ protein length scales, respectively. Our experimental results clearly indicate that the presence of surfaces with different chemical composition affect X. fastidiosa behavior from the point of view of gene expression and adhesion functionality. Bacterial adhesion is facilitated on more hydrophilic surfaces with higher surface potentials; XadA1 adhesin reveals different strengths of interaction on these surfaces. Nonetheless, despite different architectural biofilm geometries and rates of development, the colonization process occurs on all investigated surfaces. Our results univocally support the hypothesis that different adhesion mechanisms are active along the biofilm life cycle representing an adaptation mechanism for variations on the specific xylem vessel composition, which the bacterium encounters within the infected plant.

  13. Xylella fastidiosa esterase rather than hydroxynitrile lyase.

    PubMed

    Torrelo, Guzman; Ribeiro de Souza, Fayene Zeferino; Carrilho, Emanuel; Hanefeld, Ulf

    2015-03-02

    In 2009, we reported that the product of the gene SCJ21.16 (XFa0032) from Xylella fastidiosa, a xylem-restricted plant pathogen that causes a range of diseases in several important crops, encodes a protein (XfHNL) with putative hydroxynitrile lyase activity. Sequence analysis and activity tests indicated that XfHNL exhibits an α/β-hydrolase fold and could be classified as a member of the family of FAD-independent HNLs. Here we provide a more detailed sequence analysis and new experimental data. Using pure heterologously expressed XfHNL we show that this enzyme cannot catalyse the cleavage/synthesis of mandelonitrile and that this protein is in fact a non-enantioselective esterase. Homology modelling and ligand docking simulations were used to study the active site and support these results. This finding could help elucidate the common ancestor of esterases and hydroxynitrile lyases with an α/β -hydrolase fold.

  14. Xylella fastidiosa differentially accumulates mineral elements in biofilm and planktonic cells.

    PubMed

    Cobine, Paul A; Cruz, Luisa F; Navarrete, Fernando; Duncan, Daniel; Tygart, Melissa; De La Fuente, Leonardo

    2013-01-01

    Xylella fastidiosa is a bacterial plant pathogen that infects numerous plant hosts. Disease develops when the bacterium colonizes the xylem vessels and forms a biofilm. Inductively coupled plasma optical emission spectroscopy was used to examine the mineral element content of this pathogen in biofilm and planktonic states. Significant accumulations of copper (30-fold), manganese (6-fold), zinc (5-fold), calcium (2-fold) and potassium (2-fold) in the biofilm compared to planktonic cells were observed. Other mineral elements such as sodium, magnesium and iron did not significantly differ between biofilm and planktonic cells. The distribution of mineral elements in the planktonic cells loosely mirrors the media composition; however the unique mineral element distribution in biofilm suggests specific mechanisms of accumulation from the media. A cell-to-surface attachment assay shows that addition of 50 to 100 µM Cu to standard X. fastidiosa media increases biofilm, while higher concentrations (>200 µM) slow cell growth and prevent biofilm formation. Moreover cell-to-surface attachment was blocked by specific chelation of copper. Growth of X. fastidiosa in microfluidic chambers under flow conditions showed that addition of 50 µM Cu to the media accelerated attachment and aggregation, while 400 µM prevented this process. Supplementation of standard media with Mn showed increased biofilm formation and cell-to-cell attachment. In contrast, while the biofilm accumulated Zn, supplementation to the media with this element caused inhibited growth of planktonic cells and impaired biofilm formation. Collectively these data suggest roles for these minerals in attachment and biofilm formation and therefore the virulence of this pathogen.

  15. In vitro Determination of Extracellular Proteins from Xylella fastidiosa

    PubMed Central

    Mendes, Juliano S.; Santiago, André S.; Toledo, Marcelo A. S.; Horta, Maria A. C.; de Souza, Alessandra A.; Tasic, Ljubica; de Souza, Anete P.

    2016-01-01

    The phytopathogen Xylella fastidiosa causes economic losses in important agricultural crops. Xylem vessel occlusion caused by biofilm formation is the major mechanism underlying the pathogenicity of distinct strains of X. fastidiosa. Here, we provide a detailed in vitro characterization of the extracellular proteins of X. fastidiosa. Based on the results, we performed a comparison with a strain J1a12, which cannot induce citrus variegated chlorosis symptoms when inoculated into citrus plants. We then extend this approach to analyze the extracellular proteins of X. fastidiosa in media supplemented with calcium. We verified increases in extracellular proteins concomitant with the days of growth and, consequently, biofilm development (3–30 days). Outer membrane vesicles carrying toxins were identified beginning at 10 days of growth in the 9a5c strain. In addition, a decrease in extracellular proteins in media supplemented with calcium was observed in both strains. Using mass spectrometry, 71 different proteins were identified during 30 days of X. fastidiosa biofilm development, including proteases, quorum-sensing proteins, biofilm formation proteins, hypothetical proteins, phage-related proteins, chaperones, toxins, antitoxins, and extracellular vesicle membrane components. PMID:28082960

  16. Impact of pymetrozine on glassy-winged sharpshooter feeding behavior and rate of Xylella fastidiosa transmission

    PubMed Central

    Bextine, B.R.; Harshman, D.; Johnson, M.C.; Miller, T.A.

    2004-01-01

    Pymetrozine is a compound that interferes with insect feeding and interrupts transmission of plant pathogens. The glassy-winged sharpshooter, Homalodisca coagulata Say (Hemiptera, Cicadellidae), is a vector of Xylella fastidiosa, the foregut-borne, propagative bacterium that causes Pierce's disease of grapevine. In this study, we recorded the behavioral response of H. coagulata to plants treated by soil drench with pymetrozine using time-lapse photography, quantified the reduction in liquid excreta produced by H. coagulata fed on pymetrozine-treated plants, and evaluated pymetrozine effectiveness in reducing transmission rate in grapevines. H. coagulata feeding on plants treated with 0.015 mg of pymetrozine was disrupted by decreasing the number of contacts made with the grapevine by more than 50% and by increasing movements away from the stem by more than 5-fold. Excreta production by H. coagulata was significantly reduced on plants treated with 0.015 or 0.0075 mg of pymetrozine. Contrary to the expected outcome, the mean number of X. fastidiosa-infected plants actually increased in the pymetrozine treatments relative to the controls. PMID:15861249

  17. Impact of pymetrozine on glassy-winged sharpshooter feeding behavior and rate of Xylella fastidiosa transmission.

    PubMed

    Bextine, B R; Harshman, D; Johnson, M C; Miller, T A

    2004-01-01

    Pymetrozine is a compound that interferes with insect feeding and interrupts transmission of plant pathogens. The glassy-winged sharpshooter, Homalodisca coagulata Say (Hemiptera, Cicadellidae), is a vector of Xylella fastidiosa, the foregut-borne, propagative bacterium that causes Pierce's disease of grapevine. In this study, we recorded the behavioral response of H. coagulata to plants treated by soil drench with pymetrozine using time-lapse photography, quantified the reduction in liquid excreta produced by H. coagulata fed on pymetrozine-treated plants, and evaluated pymetrozine effectiveness in reducing transmission rate in grapevines. H. coagulata feeding on plants treated with 0.015 mg of pymetrozine was disrupted by decreasing the number of contacts made with the grapevine by more than 50% and by increasing movements away from the stem by more than 5-fold. Excreta production by H. coagulata was significantly reduced on plants treated with 0.015 or 0.0075 mg of pymetrozine. Contrary to the expected outcome, the mean number of X. fastidiosa-infected plants actually increased in the pymetrozine treatments relative to the controls.

  18. Fractal analysis of Xylella fastidiosa biofilm formation

    NASA Astrophysics Data System (ADS)

    Moreau, A. L. D.; Lorite, G. S.; Rodrigues, C. M.; Souza, A. A.; Cotta, M. A.

    2009-07-01

    We have investigated the growth process of Xylella fastidiosa biofilms inoculated on a glass. The size and the distance between biofilms were analyzed by optical images; a fractal analysis was carried out using scaling concepts and atomic force microscopy images. We observed that different biofilms show similar fractal characteristics, although morphological variations can be identified for different biofilm stages. Two types of structural patterns are suggested from the observed fractal dimensions Df. In the initial and final stages of biofilm formation, Df is 2.73±0.06 and 2.68±0.06, respectively, while in the maturation stage, Df=2.57±0.08. These values suggest that the biofilm growth can be understood as an Eden model in the former case, while diffusion-limited aggregation (DLA) seems to dominate the maturation stage. Changes in the correlation length parallel to the surface were also observed; these results were correlated with the biofilm matrix formation, which can hinder nutrient diffusion and thus create conditions to drive DLA growth.

  19. Emendation of the Genus Actinokineospora Hasegawa 1988 and Transfer of Amycolatopsis fastidiosa Henssen et al. 1987 as Actinokineospora fastidiosa comb. nov

    USDA-ARS?s Scientific Manuscript database

    The species Amycolatopsis fastidiosa was proposed by Henssen et al. (1987), based on morphological and chemotaxonomic observations, for a strain originally described as 'Pseudonocardia fastidiosa' by Celmer et al. in a US Patent issued in 1977. In the course of a phylogenetic study of the valid tax...

  20. Modulation of Protein Phosphorylation, N-Glycosylation and Lys-Acetylation in Grape (Vitis vinifera) Mesocarp and Exocarp Owing to Lobesia botrana Infection*

    PubMed Central

    Melo-Braga, Marcella N.; Verano-Braga, Thiago; León, Ileana R.; Antonacci, Donato; Nogueira, Fábio C. S.; Thelen, Jay J.; Larsen, Martin R.; Palmisano, Giuseppe

    2012-01-01

    light on the mechanisms underlying the grape infection. PMID:22778145

  1. Modulation of protein phosphorylation, N-glycosylation and Lys-acetylation in grape (Vitis vinifera) mesocarp and exocarp owing to Lobesia botrana infection.

    PubMed

    Melo-Braga, Marcella N; Verano-Braga, Thiago; León, Ileana R; Antonacci, Donato; Nogueira, Fábio C S; Thelen, Jay J; Larsen, Martin R; Palmisano, Giuseppe

    2012-10-01

    light on the mechanisms underlying the grape infection.

  2. Extracellular Xylella fastidiosa genomic DNA enhances biofilm formation in vitro

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf) is a Gram negative, xylem-limited bacterium that causes Pierce’s Disease (PD) of grapevine, as well as other diseases of economically important crops and landscape plants. Many bacteria produce large amounts of extracellular DNA, which may function as a matrix component in b...

  3. Testing Xylella fastidiosa pathogenesis mutants in Arabidopsis thaliana

    USDA-ARS?s Scientific Manuscript database

    The bacterium Xylella fastidiosa (Xf) causes Pierce's disease and a number of other plant diseases of significant economic impact. To date, progress determining mechanisms of host plant susceptibility, tolerance or resistance has been slow, due in large part to the long generation time and limited ...

  4. Phenotype Overlap in Xylella fastidiosa Is Controlled by the Cyclic Di-GMP Phosphodiesterase Eal in Response to Antibiotic Exposure and Diffusible Signal Factor-Mediated Cell-Cell Signaling

    PubMed Central

    de Souza, Alessandra A.; Ionescu, Michael; Baccari, Clelia; da Silva, Aline M.

    2013-01-01

    Eal is an EAL domain protein in Xylella fastidiosa homologous to one involved in resistance to tobramycin in Pseudomonas aeruginosa. EAL and HD-GYP domain proteins are implicated in the hydrolysis of the secondary messenger bis-(3′-5′)-cyclic dimeric GMP (cyclic di-GMP). Cell density-dependent communication mediated by a Diffusible Signal Factor (DSF) also modulates cyclic di-GMP levels in X. fastidiosa, thereby controlling the expression of virulence genes and genes involved in insect transmission. The possible linkage of Eal to both extrinsic factors such as antibiotics and intrinsic factors such as quorum sensing, and whether both affect virulence, was thus addressed. Expression of eal was induced by subinhibitory concentrations of tobramycin, and an eal deletion mutant was more susceptible to this antibiotic than the wild-type strain and exhibited phenotypes similar to those of an rpfF deletion mutant blocked in DSF production, such as hypermotility, reduced biofilm formation, and hypervirulence to grape. Consistent with that, the rpfF mutant was more susceptible than the wild-type strain to tobramycin. Therefore, we propose that cell-cell communication and antibiotic stress can apparently lead to similar modulations of cyclic di-GMP in X. fastidiosa, resulting in similar phenotypes. However, the effect of cell density is dominant compared to that of antibiotic stress, since eal is suppressed by RpfF, which may prevent inappropriate behavioral changes in response to antibiotic stress when DSF accumulates. PMID:23542613

  5. Phenotype overlap in Xylella fastidiosa is controlled by the cyclic di-GMP phosphodiesterase Eal in response to antibiotic exposure and diffusible signal factor-mediated cell-cell signaling.

    PubMed

    de Souza, Alessandra A; Ionescu, Michael; Baccari, Clelia; da Silva, Aline M; Lindow, Steven E

    2013-06-01

    Eal is an EAL domain protein in Xylella fastidiosa homologous to one involved in resistance to tobramycin in Pseudomonas aeruginosa. EAL and HD-GYP domain proteins are implicated in the hydrolysis of the secondary messenger bis-(3'-5')-cyclic dimeric GMP (cyclic di-GMP). Cell density-dependent communication mediated by a Diffusible Signal Factor (DSF) also modulates cyclic di-GMP levels in X. fastidiosa, thereby controlling the expression of virulence genes and genes involved in insect transmission. The possible linkage of Eal to both extrinsic factors such as antibiotics and intrinsic factors such as quorum sensing, and whether both affect virulence, was thus addressed. Expression of eal was induced by subinhibitory concentrations of tobramycin, and an eal deletion mutant was more susceptible to this antibiotic than the wild-type strain and exhibited phenotypes similar to those of an rpfF deletion mutant blocked in DSF production, such as hypermotility, reduced biofilm formation, and hypervirulence to grape. Consistent with that, the rpfF mutant was more susceptible than the wild-type strain to tobramycin. Therefore, we propose that cell-cell communication and antibiotic stress can apparently lead to similar modulations of cyclic di-GMP in X. fastidiosa, resulting in similar phenotypes. However, the effect of cell density is dominant compared to that of antibiotic stress, since eal is suppressed by RpfF, which may prevent inappropriate behavioral changes in response to antibiotic stress when DSF accumulates.

  6. Visualization of twitching motility and characterization of the role of the PilG in Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a Gram-negative non-flagellated bacterium that causes a number of economically important diseases of plants. Twitching motility provides X. fastidiosa a means for long-distance intra-plant movement and colonization, contributing toward pathogenicity of X. fastidiosa. Twitching ...

  7. Survey of the auchenorrhyncha in the Salento Peninsula in search of putative vectors of Xylella fastidiosa Pauca Codiro strain

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa was isolated in September 2013 from olive trees symptomatic for Olive Quick Decline Syndrome (OQDS) in Salento (Italy) and was identified as X. fastidiosa pauca CoDiRO strain. X. fastidiosa is comprised of a group of genetically diverse bacteria in the class Gammaproteobacteria th...

  8. Selection of single chain variable fragments (scFv) against Xylella fastidiosa subsp. pauca by phage display

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a gram-negative member of the gamma proteobacteria. Xylella fastidiosa subsp pauca causes citrus variegated chlorosis in Brazil and enjoys ‘select agent’ status in the United States. Antibody based detection assays are commercially available for Xylella fastidiosa, and are ef...

  9. Natural competence and recombination in the plant pathogen Xylella fastidiosa.

    PubMed

    Kung, Stephanie H; Almeida, Rodrigo P P

    2011-08-01

    Homologous recombination is one of many forces contributing to the diversity, adaptation, and emergence of pathogens. For naturally competent bacteria, transformation is one possible route for the acquisition of novel genetic material. This study demonstrates that Xylella fastidiosa, a generalist bacterial plant pathogen responsible for many emerging plant diseases, is naturally competent and able to homologously recombine exogenous DNA into its genome. Several factors that affect transformation and recombination efficiencies, such as nutrient availability, growth stage, and methylation of transforming DNA, were identified. Recombination was observed in at least one out of every 10(6) cells when exogenous plasmid DNA was supplied and one out of every 10(7) cells when different strains were grown together in vitro. Based on previous genomic studies and experimental data presented here, there is mounting evidence that recombination can occur at relatively high rates and could play a large role in shaping the genetic diversity of X. fastidiosa.

  10. Proteome Biomarkers in Xylem Reveal Pierce’s Disease Tolerance in Grape

    PubMed Central

    Katam, Ramesh; Chibanguza, Kundai; Latinwo, Lekan M; Smith, Danyel

    2016-01-01

    Pierce’s disease (PD) is a significant threat to grape cultivation and industry. The disease caused by bacterium Xylella fastidiosa clogs xylem vessels resulting in wilting of the plant. PD-tolerant grape genotypes are believed to produce certain novel components in xylem tissue that help them to combat invading pathogens. Research has been aimed at characterizing the uniquely expressed xylem proteins by PD-tolerant genotypes. The objectives were to i) compare and characterize Vitis xylem proteins differentially expressed in PD-tolerant and PD-susceptible cultivars and, ii) identify xylem proteins uniquely expressed in PD-tolerant genotypes. A high throughput two-dimensional gel electrophoresis of xylem proteins from three Vitis species identified more than 200 proteins with pls 3.0 to 9.0 and molecular weights of 20 to 75 kDa. The differentially expressed proteins were then excised and analyzed with MALDI/TOF mass spectrometer. The mass spectra were collected and protein identification was performed against the Viridiplantae database using Matrix Science algorithm. Proteins were mapped to the universal protein resource to study gene ontology. Comparative analysis of the xylem proteome of three species indicated the highest number of proteins in muscadine grape, followed by Florida hybrid bunch and bunch grape. These proteins were all associated with disease resistance, energy metabolism, protein processing and degradation, biosynthesis, stress related functions, cell wall biogenesis, signal transduction, and ROS detoxification. Furthermore, β-1, 3-glucanase, 10-deacetyl baccatin III-10-O-acetyl transferase-like, COP9, and aspartyl protease nepenthesin precursor proteins were found to be uniquely expressed in PD-tolerant muscadine grape, while they are absent in PD-susceptible bunch grape. Data suggests that muscadine and Florida hybrid bunch grapes express novel proteins in xylem to overcome pathogen attack while bunch grape lacks this capability, making them

  11. Conjugative plasmid transfer in Xylella fastidiosa is dependent on tra and trb operon functions

    USDA-ARS?s Scientific Manuscript database

    The insect-transmitted plant pathogen Xylella fastidiosa is capable of efficient horizontal gene transfer and recombination, leading to diversity between strains and the categorization of X. fastidiosa into multiple subspecies. Although natural transformation is shown to occur at high rates in X. fa...

  12. Evaluation of olive as a host of Xylella fastidiosa and associated sharpshooter vectors

    USDA-ARS?s Scientific Manuscript database

    Olive (Olea europaea L.) trees exhibiting leaf scorch and/or branch dieback symptoms in California were surveyed for the xylem-limited, fastidious bacterium Xylella fastidiosa. Only ~17% of diseased trees tested positive for X. fastidiosa by PCR, and disease symptoms could not be attributed to X. fa...

  13. Xylella fastidiosa in rabbiteye blueberry: A newly studied host of an old foe

    USDA-ARS?s Scientific Manuscript database

    The bacterium Xylella fastidiosa causes a number of plant diseases, including bacterial leaf scorch of southern highbush blueberry. In Louisiana, X. fastidiosa has been detected in rabbiteye blueberry orchards, and we wanted to know if it affected yield in rabbiteye blueberry plants. We detected X...

  14. Identification of novel secreted virulence factors from Xylella fastidiosa using a TRV expression system

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a bacterium that causes leaf scorch diseases of agriculturally important crops including grapevines and almonds. Little is known about virulence factors that are necessary for X. fastidiosa to grow and cause disease in the xylem vessels of a plant host. Any protein secreted by ...

  15. Origins of the Xylella fastidiosa prophage-like regions and their impact in genome differentiation

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a Gram negative plant pathogen causing many economically important diseases, and analyses of completely sequenced X. fastidiosa genome strains allowed the identification of many prophage-like elements and possibly phage remnants, accounting for up to 15% of the genome compositi...

  16. Variations of whole genome sequences of Xylella fastidiosa strains within the same pathotype

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a Gram negative and nutritionally fastidious plant pathogenic bacterium that causes almond leaf scorch disease (ALSD) and Pierce's disease (PD) of grapevine. X. fastidiosa strains from almond can be divided into two pathotypes: ALSD-PD, represented by strain M23, and ALSD-only,...

  17. Functional characterization of the role of the PilG in Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Type IV pili of Xylella fastidiosa are regulated by pilG, a chemotaxis regulator in the Pil-Chp operon involving signal transduction pathways. To elucidate the role of pilG in twitching motility and pathogenicity of X. fastidiosa, phenotypes of wild type, a pilG-mutant, and a complementary strain we...

  18. Comparative genomic characterization of citrus-associated Xylella fastidiosa strains

    PubMed Central

    da Silva, Vivian S; Shida, Cláudio S; Rodrigues, Fabiana B; Ribeiro, Diógenes CD; de Souza, Alessandra A; Coletta-Filho, Helvécio D; Machado, Marcos A; Nunes, Luiz R; de Oliveira, Regina Costa

    2007-01-01

    Background The xylem-inhabiting bacterium Xylella fastidiosa (Xf) is the causal agent of Pierce's disease (PD) in vineyards and citrus variegated chlorosis (CVC) in orange trees. Both of these economically-devastating diseases are caused by distinct strains of this complex group of microorganisms, which has motivated researchers to conduct extensive genomic sequencing projects with Xf strains. This sequence information, along with other molecular tools, have been used to estimate the evolutionary history of the group and provide clues to understand the capacity of Xf to infect different hosts, causing a variety of symptoms. Nonetheless, although significant amounts of information have been generated from Xf strains, a large proportion of these efforts has concentrated on the study of North American strains, limiting our understanding about the genomic composition of South American strains – which is particularly important for CVC-associated strains. Results This paper describes the first genome-wide comparison among South American Xf strains, involving 6 distinct citrus-associated bacteria. Comparative analyses performed through a microarray-based approach allowed identification and characterization of large mobile genetic elements that seem to be exclusive to South American strains. Moreover, a large-scale sequencing effort, based on Suppressive Subtraction Hybridization (SSH), identified 290 new ORFs, distributed in 135 Groups of Orthologous Elements, throughout the genomes of these bacteria. Conclusion Results from microarray-based comparisons provide further evidence concerning activity of horizontally transferred elements, reinforcing their importance as major mediators in the evolution of Xf. Moreover, the microarray-based genomic profiles showed similarity between Xf strains 9a5c and Fb7, which is unexpected, given the geographical and chronological differences associated with the isolation of these microorganisms. The newly identified ORFs, obtained by

  19. Xylella fastidiosa gene expression analysis by DNA microarrays

    PubMed Central

    2009-01-01

    Xylella fastidiosa genome sequencing has generated valuable data by identifying genes acting either on metabolic pathways or in associated pathogenicity and virulence. Based on available information on these genes, new strategies for studying their expression patterns, such as microarray technology, were employed. A total of 2,600 primer pairs were synthesized and then used to generate fragments using the PCR technique. The arrays were hybridized against cDNAs labeled during reverse transcription reactions and which were obtained from bacteria grown under two different conditions (liquid XDM2 and liquid BCYE). All data were statistically analyzed to verify which genes were differentially expressed. In addition to exploring conditions for X. fastidiosa genome-wide transcriptome analysis, the present work observed the differential expression of several classes of genes (energy, protein, amino acid and nucleotide metabolism, transport, degradation of substances, toxins and hypothetical proteins, among others). The understanding of expressed genes in these two different media will be useful in comprehending the metabolic characteristics of X. fastidiosa, and in evaluating how important certain genes are for the functioning and survival of these bacteria in plants. PMID:21637690

  20. Detection and differentiation of Xylella fastidiosa strains acquired and retained by glassy-winged sharpshooters (Hemiptera: Cicadellidae) using a mixture of strain-specific primer sets.

    PubMed

    Costa, H S; Guzman, A; Hernandez-Martinez, R; Gispert, C; Cooksey, D A

    2006-08-01

    Xylella fastidiosa Wells is a bacterial pathogen that causes a variety of plant diseases, including Pierce's disease (PD) of grapevine, almond leaf scorch, alfalfa dwarf, citrus variegated chlorosis, and oleander leaf scorch (OLS). Numerous strains of this pathogen have been genetically characterized, and several different strains occur in the United States. The dominant vector in southern California is the glassy-winged sharpshooter, Homalodisca coagulata (Say) (Hemiptera: Cicadellidae). The high mobility of this insect, and its use of large numbers of host plant species, provides this vector with ample exposure to multiple strains of X. fastidiosa during its lifetime. To learn more about the ability of this vector to acquire, retain, and transmit multiple strains of the pathogen, we developed a polymerase chain reaction (PCR)-based method to detect and differentiate strains of X. fastidiosa present in individual glassy-winged sharpshooter adults. Insects were sequentially exposed to plants infected with a PD strain in grapevine and an OLS strain in oleander. After sequential exposure, a few insects tested positive for both strains (7%); however, in most cases individuals tested positive for only one strain (29% PD, 41% OLS). In transmission studies, individual adults transmitted either the PD or OLS strain of the pathogen at a rate (39%) similar to that previously reported after exposure to a single strain, but no single individual transmitted both strains of the pathogen. PD and OLS strains of X. fastidiosa remained detectable in glassy-winged sharpshooter, even when insects were fed on a plant species that was not a host of the strain for 1 wk.

  1. Melatonin in grapes and grape-related foodstuffs: A review.

    PubMed

    Meng, Jiang-Fei; Shi, Tian-Ci; Song, Shuo; Zhang, Zhen-Wen; Fang, Yu-Lin

    2017-09-15

    A decade has passed since melatonin was first reported in grapes in 2006. During this time, melatonin has not only been found in the berries of most wine grape (Vitis vinifera L.) cultivars, but also in most grape-related foodstuffs, e.g. wine, grape juice and grape vinegar. In this review, we discuss the melatonin content in grapes and grape-related foodstuffs (especially wine) from previous studies, the physiological function of melatonin in grapes, and the factors contributing to the production of melatonin in grapes and wines. In addition, we identify future research needed to clarify the mechanisms of grape melatonin biosynthesis and regulation, and establish more accurate analysis methods for melatonin in grapes and wines. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Transcriptional Regulation of Grape Cytochrome P450 Gene Expression in Response to Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Plant cytochrome P450 monooxygenases are versatile redox proteins that mediate biosynthesis of lignins, terpenes, alkaloids, and a variety of other secondary compounds as plant defense agents against a range of pathogens and insects. To determine if cytochrome P450 monooxygenases are involved in the...

  3. Relative Susceptibility of Vitis vinifera Cultivars to Vector-Borne Xylella fastidiosa through Time

    PubMed Central

    Rashed, Arash; Kwan, Joyce; Baraff, Breanna; Ling, Diane; Daugherty, Matthew P.; Killiny, Nabil; Almeida, Rodrigo P. P.

    2013-01-01

    Understanding the interactions between pathogen, crop and vector are necessary for the development of disease control practices of vector-borne pathogens. For instance, resistant plant genotypes can help constrain disease symptoms due to infections and limit pathogen spread by vectors. On the other hand, genotypes susceptible to infection may increase pathogen spread owing to their greater pathogen quantity, regardless of their symptom status. In this study, we evaluated under greenhouse conditions the relative levels of resistance (i.e. relatively lower pathogen quantity) versus tolerance (i.e. less symptom severity) of 10 commercial grapevine (Vitis vinifera) cultivars to Pierce’s disease etiological agent, the bacterium Xylella fastidiosa. Overall, no correlation was detected between pathogen quantity and disease severity, indicating the existence of among-cultivar variation in plant response to infection. Thompson Seedless and Barbera were the two most susceptible among 10 evaluated cultivars. Rubired showed the least severe disease symptoms and was categorized as one of the most resistant genotypes in this study. However, within each cultivar the degree of resistance/tolerance was not consistent across sampling dates. These cultivar and temporal differences in susceptibility to infection may have important consequences for disease epidemiology and the effectiveness of management protocols. PMID:23424629

  4. Relative susceptibility of Vitis vinifera cultivars to vector-borne Xylella fastidiosa through time.

    PubMed

    Rashed, Arash; Kwan, Joyce; Baraff, Breanna; Ling, Diane; Daugherty, Matthew P; Killiny, Nabil; Almeida, Rodrigo P P

    2013-01-01

    Understanding the interactions between pathogen, crop and vector are necessary for the development of disease control practices of vector-borne pathogens. For instance, resistant plant genotypes can help constrain disease symptoms due to infections and limit pathogen spread by vectors. On the other hand, genotypes susceptible to infection may increase pathogen spread owing to their greater pathogen quantity, regardless of their symptom status. In this study, we evaluated under greenhouse conditions the relative levels of resistance (i.e. relatively lower pathogen quantity) versus tolerance (i.e. less symptom severity) of 10 commercial grapevine (Vitis vinifera) cultivars to Pierce's disease etiological agent, the bacterium Xylella fastidiosa. Overall, no correlation was detected between pathogen quantity and disease severity, indicating the existence of among-cultivar variation in plant response to infection. Thompson Seedless and Barbera were the two most susceptible among 10 evaluated cultivars. Rubired showed the least severe disease symptoms and was categorized as one of the most resistant genotypes in this study. However, within each cultivar the degree of resistance/tolerance was not consistent across sampling dates. These cultivar and temporal differences in susceptibility to infection may have important consequences for disease epidemiology and the effectiveness of management protocols.

  5. The complex biogeography of the plant pathogen Xylella fastidiosa: genetic evidence of introductions and Subspecific introgression in Central America.

    PubMed

    Nunney, Leonard; Ortiz, Beatriz; Russell, Stephanie A; Ruiz Sánchez, Rebeca; Stouthamer, Richard

    2014-01-01

    The bacterium Xylella fastidiosa is a plant pathogen with a history of economically damaging introductions of subspecies to regions where its other subspecies are native. Genetic evidence is presented demonstrating the introduction of two new taxa into Central America and their introgression into the native subspecies, X. fastidiosa subsp. fastidiosa. The data are from 10 genetic outliers detected by multilocus sequence typing (MLST) of isolates from Costa Rica. Six (five from oleander, one from coffee) defined a new sequence type (ST53) that carried alleles at six of the eight loci sequenced (five of the seven MLST loci) diagnostic of the South American subspecies Xylella fastidiosa subsp. pauca which causes two economically damaging plant diseases, citrus variegated chlorosis and coffee leaf scorch. The two remaining loci of ST53 carried alleles from what appears to be a new South American form of X. fastidiosa. Four isolates, classified as X. fastidiosa subsp. fastidiosa, showed a low level of introgression of non-native DNA. One grapevine isolate showed introgression of an allele from X. fastidiosa subsp. pauca while the other three (from citrus and coffee) showed introgression of an allele with similar ancestry to the alleles of unknown origin in ST53. The presence of X. fastidiosa subsp. pauca in Central America is troubling given its disease potential, and establishes another route for the introduction of this economically damaging subspecies into the US or elsewhere, a threat potentially compounded by the presence of a previously unknown form of X. fastidiosa.

  6. Characterization of an oxidative stress response regulator, homologous to Escherichia coli OxyR, from the phytopathogen Xylella fastidiosa.

    PubMed

    Toledo, M A S; Schneider, D R; Azzoni, A R; Favaro, M T P; Pelloso, A C; Santos, C A; Saraiva, A M; Souza, A P

    2011-02-01

    The OxyR oxidative stress transcriptional regulator is a DNA-binding protein that belongs to the LysR-type transcriptional regulators (LTTR) family. It has the ability to sense oxidative species inside the cell and to trigger the cell's response, activating the transcription of genes involved in scavenging oxidative species. In the present study, we have overexpressed, purified and characterized the predicted OxyR homologue (orf xf1273) of the phytopathogen Xylella fastidiosa. This bacterium is the causal agent of citrus variegated chlorosis (CVC) disease caused by the 9a5c strain, resulting in economic and social losses. The secondary structure of the recombinant protein was analyzed by circular dichroism. Gel filtration showed that XfoxyR is a dimer in solution. Gel shift assays indicated that it does bind to its own predicted promoter under in vitro conditions. However, considering our control experiment we cannot state that this interaction occurs in vivo. Functional complementation assays indicated that xfoxyR is able to restore the oxidative stress response in an oxyr knockout Escherichia coli strain. These results show that the predicted orfxf1273 codes for a transcriptional regulator, homologous to E. coli OxyR, involved in the oxidative stress response. This may be important for X. fastidiosa to overcome the defense mechanisms of its host during the infection and colonization processes.

  7. Promiscuous Diffusible Signal Factor Production and Responsiveness of the Xylella fastidiosa Rpf System

    PubMed Central

    Ionescu, Michael; Yokota, Kenji; Antonova, Elena; Garcia, Angelica; Beaulieu, Ellen; Hayes, Terry; Iavarone, Anthony T.

    2016-01-01

    ABSTRACT Cell density-dependent regulation of gene expression in Xylella fastidiosa that is crucial to its switching between plant hosts and insect vectors is dependent on RpfF and its production of 2-enoic acids known as diffusible signal factor (DSF). We show that X. fastidiosa produces a particularly large variety of similar, relatively long-chain-length 2-enoic acids that are active in modulating gene expression. Both X. fastidiosa itself and a Pantoea agglomerans surrogate host harboring X. fastidiosa RpfF (XfRpfF) is capable of producing a variety of both saturated and unsaturated free fatty acids. However, only 2-cis unsaturated acids were found to be biologically active in X. fastidiosa. X. fastidiosa produces, and is particularly responsive to, a novel DSF species, 2-cis-hexadecanoic acid that we term XfDSF2. It is also responsive to other, even longer 2-enoic acids to which other taxa such as Xanthomonas campestris are unresponsive. The 2-enoic acids that are produced by X. fastidiosa are strongly affected by the cellular growth environment, with XfDSF2 not detected in culture media in which 2-tetradecenoic acid (XfDSF1) had previously been found. X. fastidiosa is responsive to much lower concentrations of XfDSF2 than XfDSF1. Apparently competitive interactions can occur between various saturated and unsaturated fatty acids that block the function of those agonistic 2-enoic fatty acids. By altering the particular 2-enoic acids produced and the relative balance of free enoic and saturated fatty acids, X. fastidiosa might modulate the extent of DSF-mediated quorum sensing. PMID:27435463

  8. Anthocyanins in grapes and grape products.

    PubMed

    Mazza, G

    1995-07-01

    The types of anthocyanins occurring in grapes, wines, and juices are described and their distribution documented. Recent work on the evaluation of red wine color during storage and aging is reviewed. Molecular interactions between anthocyanins and some of the other red wine molecules are shown to be associated with development of new pigments whose formation explains the subtle color changes and stabilization occurring on aging of red wines. A detailed description of the recovery of anthocyanins from grape pomace and production of natural red colorants is also given.

  9. Effect of oxygen on the growth and biofilm formation of Xylella fastidiosa in liquid media.

    PubMed

    Shriner, Anthony D; Andersen, Peter C

    2014-12-01

    Xylella fastidiosa is a xylem-limited bacterial pathogen, and is the causative agent of Pierce's disease of grapevines and scorch diseases of many other plant species. The disease symptoms are putatively due to blocking of the transpiration stream by bacterial-induced biofilm formation and/or by the formation of plant-generated tylosis. Xylella fastidiosa has been classified as an obligate aerobe, which appears unusual given that dissolved O2 levels in the xylem during the growing season are often hypoxic (20-60 μmol L(-1)). We examined the growth and biofilm formation of three strains of X. fastidiosa under variable O2 conditions (21, 2.1, 0.21 and 0 % O2), in comparison to that of Pseudomonas syringae (obligate aerobe) and Erwinia carotovora (facultative anaerobe) under similar conditions. The growth of X. fastidiosa more closely resembled that of the facultative anaerobe, and not the obligate aerobe. Xanthomonas campestris, the closest genetic relative of X. fastidiosa, exhibited no growth in an N2 environment, whereas X. fastidiosa was capable of growing in an N2 environment in PW(+), CHARDS, and XDM2-PR media. The magnitude of growth and biofilm formation in the N2 (0 % O2) treatment was dependent on the specific medium. Additional studies involving the metabolism of X. fastidiosa in response to low O2 are warranted. Whether X. fastidiosa is classified as an obligate aerobe or a facultative anaerobe should be confirmed by gene activation and/or the quantification of the metabolic profiles under hypoxic conditions.

  10. The Xylella fastidiosa PD1063 protein is secreted in association with outer membrane vesicles.

    PubMed

    Pierce, Brittany K; Voegel, Tanja; Kirkpatrick, Bruce C

    2014-01-01

    Xylella fastidiosa is a gram-negative, xylem-limited plant pathogenic bacterium that causes disease in a variety of economically important agricultural crops including Pierce's disease of grapevines. Xylella fastidiosa biofilms formed in the xylem vessels of plants play a key role in early colonization and pathogenicity by providing a protected niche and enhanced cell survival. Here we investigate the role of Xylella fastidiosa PD1063, the predicted ortholog of Xanthomonas oryzae pv. oryzae PXO_03968, which encodes an outer membrane protein. To assess the function of the Xylella fastidiosa ortholog, we created Xylella fastidiosa mutants deleted for PD1063 and then assessed biofilm formation, cell-cell aggregation and cell growth in vitro. We also assessed disease severity and pathogen titers in grapevines mechanically inoculated with the Xylella fastidiosa PD1063 mutant. We found a significant decrease in cell-cell aggregation among PD1063 mutants but no differences in cell growth, biofilm formation, disease severity or titers in planta. Based on the demonstration that Xanthomonas oryzae pv. oryzae PXO_03968 encodes an outer membrane protein, secreted in association with outer membrane vesicles, we predicted that PD1063 would also be secreted in a similar manner. Using anti-PD1063 antibodies, we found PD1063 in the supernatant and secreted in association with outer membrane vesicles. PD1063 purified from the supernatant, outer membrane fractions and outer membrane vesicles was 19.2 kD, corresponding to the predicted size of the processed protein. Our findings suggest Xylella fastidiosa PD1063 is not essential for development of Pierce's disease in Vitis vinifera grapevines although further research is required to determine the function of the PD1063 outer membrane protein in Xylella fastidiosa.

  11. A putative twin-arginine translocation system in the phytopathogenic bacterium Xylella fastidiosa.

    PubMed

    Ciapina, Luciane Prioli; Picchi, Simone Cristina; Lacroix, Jean-Marie; Lemos, Eliana Gertrudes de Macedo; Ödberg-Ferragut, Carmen

    2011-02-01

    The twin-arginine translocation (Tat) pathway of the xylem-limited phytopathogenic bacterium Xylella fastidiosa strain 9a5c, responsible for citrus variegated chlorosis, was explored. The presence of tatA, tatB, and tatC in the X. fastidiosa genome together with a list of proteins harboring 2 consecutive arginines in their signal peptides suggested the presence of a Tat pathway. The functional Tat dependence of X. fastidiosa OpgD was examined. Native or mutated signal peptides were fused to the β-lactamase. Expression of fusion with intact signal peptides mediated high resistance to ampicillin in Escherichia coli tat+ but not in the E. coli tat null mutant. The replacement of the 2 arginines by 2 lysines prevented the export of β-lactamase in E. coli tat+, demonstrating that X. fastidiosa OpgD carries a signal peptide capable of engaging the E. coli Tat machinery. RT-PCR analysis revealed that the tat genes are transcribed as a single operon. tatA, tatB, and tatC genes were cloned. Complementation assays in E. coli devoid of all Tat or TatC components were unsuccessful, whereas X. fastidiosa Tat components led to a functional Tat translocase in E. coli TatB-deficient strain. Additional experiments implicated that X. fastidiosa TatB component could form a functional heterologous complex with the E. coli TatC component.

  12. Direct Evidence of Egestion and Salivation of Xylella fastidiosa Suggests Sharpshooters Can Be "Flying Syringes".

    PubMed

    Backus, Elaine A; Shugart, Holly J; Rogers, Elizabeth E; Morgan, J Kent; Shatters, Robert

    2015-05-01

    Xylella fastidiosa is unique among insect-transmitted plant pathogens because it is propagative but noncirculative, adhering to and multiplying on the cuticular lining of the anterior foregut. Any inoculation mechanism for X. fastidiosa must explain how bacterial cells exit the vector's stylets via the food canal and directly enter the plant. A combined egestion-salivation mechanism has been proposed to explain these unique features. Egestion is the putative outward flow of fluid from the foregut via hypothesized bidirectional pumping of the cibarium. The present study traced green fluorescent protein-expressing X. fastidiosa or fluorescent nanoparticles acquired from artificial diets by glassy-winged sharpshooters, Homalodisca vitripennis, as they were egested into simultaneously secreted saliva. X. fastidiosa or nanoparticles were shown to mix with gelling saliva to form fluorescent deposits and salivary sheaths on artificial diets, providing the first direct, conclusive evidence of egestion by any hemipteran insect. Therefore, the present results strongly support an egestion-salivation mechanism of X. fastidiosa inoculation. Results also support that a column of fluid is transiently held in the foregut without being swallowed. Evidence also supports (but does not definitively prove) that bacteria were suspended in the column of fluid during the vector's transit from diet to diet, and were egested with the held fluid. Thus, we hypothesize that sharpshooters could be true "flying syringes," especially when inoculation occurs very soon after uptake of bacteria, suggesting the new paradigm of a nonpersistent X. fastidiosa transmission mechanism.

  13. Ochratoxigenic Aspergillus species on grapes from Chilean vineyards and Aspergillus threshold levels on grapes.

    PubMed

    Díaz, Gonzalo A; Torres, René; Vega, Mario; Latorre, Bernardo A

    2009-07-31

    This study reports the incidence of ochratoxigenic strains of Aspergillus on Chilean grapes (Vitis vinifera) and wineries, and production of OTA levels in wines with grapes having different levels of contamination with OTA-producing Aspergillus carbonarius was studied. A. carbonarius, A. niger, A. niveus, A. paradoxus, A. versicolor, A. wentii, and A. westerdijkiae were identified on apparently healthy clusters of red and white grape cultivars. However, A. carbonarius and A. niger were the most frequently identified species, more abundant on red than white grape cultivars. Aspergillus spp. populations increased between veraison and harvest, but the isolation frequencies were relatively low over the entire growing season. At the winery, A. carbonarius, A. niger and A. westerdijkiae were occasionally found in the air, exclusively during winemaking. OTA-producing strains were only found among isolates of A. carbonarius, A. niger, A. wenti, and A. westerdijkiae, producing 2 to 17 microg/L of OTA in liquid medium; however, A. westerdijkiae produced the highest OTA concentration in vitro. Red wines elaborated with 0.5% of grapes infected with an OTA-producing strain of A. carbonarius (Aspuc-SB36) exceeded the 2 microg/L of OTA tolerance established for wines by the European Community. Therefore, a threshold below 0.5% infected berries is proposed for red wines. ELISA tests proved to be useful for detecting OTA in broth culture as in wine samples.

  14. Optimizing EPG settings to record blue-green sharpshooter X waves for future studies of grape host plant resistance to Xf inoculation

    USDA-ARS?s Scientific Manuscript database

    The long-term goal of the research reported in this review is to develop methodology for assessment of grapevine resistant to sharpshooter inoculation of Xylella fastidiosa(Xf)into healthy grapevines, thereby preventing Xf infection. Such a trait would be quite different from the more common mechani...

  15. Sequence/structural analysis of xylem proteome emphasizes pathogenesis-related proteins, chitinases and β-1, 3-glucanases as key players in grapevine defense against Xylella fastidiosa.

    PubMed

    Chakraborty, Sandeep; Nascimento, Rafael; Zaini, Paulo A; Gouran, Hossein; Rao, Basuthkar J; Goulart, Luiz R; Dandekar, Abhaya M

    2016-01-01

    Background. Xylella fastidiosa, the causative agent of various plant diseases including Pierce's disease in the US, and Citrus Variegated Chlorosis in Brazil, remains a continual source of concern and economic losses, especially since almost all commercial varieties are sensitive to this Gammaproteobacteria. Differential expression of proteins in infected tissue is an established methodology to identify key elements involved in plant defense pathways. Methods. In the current work, we developed a methodology named CHURNER that emphasizes relevant protein functions from proteomic data, based on identification of proteins with similar structures that do not necessarily have sequence homology. Such clustering emphasizes protein functions which have multiple copies that are up/down-regulated, and highlights similar proteins which are differentially regulated. As a working example we present proteomic data enumerating differentially expressed proteins in xylem sap from grapevines that were infected with X. fastidiosa. Results. Analysis of this data by CHURNER highlighted pathogenesis related PR-1 proteins, reinforcing this as the foremost protein function in xylem sap involved in the grapevine defense response to X. fastidiosa. β-1, 3-glucanase, which has both anti-microbial and anti-fungal activities, is also up-regulated. Simultaneously, chitinases are found to be both up and down-regulated by CHURNER, and thus the net gain of this protein function loses its significance in the defense response. Discussion. We demonstrate how structural data can be incorporated in the pipeline of proteomic data analysis prior to making inferences on the importance of individual proteins to plant defense mechanisms. We expect CHURNER to be applicable to any proteomic data set.

  16. Sequence/structural analysis of xylem proteome emphasizes pathogenesis-related proteins, chitinases and β-1, 3-glucanases as key players in grapevine defense against Xylella fastidiosa

    PubMed Central

    Chakraborty, Sandeep; Nascimento, Rafael; Zaini, Paulo A.; Gouran, Hossein; Rao, Basuthkar J.; Goulart, Luiz R.

    2016-01-01

    Background. Xylella fastidiosa, the causative agent of various plant diseases including Pierce’s disease in the US, and Citrus Variegated Chlorosis in Brazil, remains a continual source of concern and economic losses, especially since almost all commercial varieties are sensitive to this Gammaproteobacteria. Differential expression of proteins in infected tissue is an established methodology to identify key elements involved in plant defense pathways. Methods. In the current work, we developed a methodology named CHURNER that emphasizes relevant protein functions from proteomic data, based on identification of proteins with similar structures that do not necessarily have sequence homology. Such clustering emphasizes protein functions which have multiple copies that are up/down-regulated, and highlights similar proteins which are differentially regulated. As a working example we present proteomic data enumerating differentially expressed proteins in xylem sap from grapevines that were infected with X. fastidiosa. Results. Analysis of this data by CHURNER highlighted pathogenesis related PR-1 proteins, reinforcing this as the foremost protein function in xylem sap involved in the grapevine defense response to X. fastidiosa. β-1, 3-glucanase, which has both anti-microbial and anti-fungal activities, is also up-regulated. Simultaneously, chitinases are found to be both up and down-regulated by CHURNER, and thus the net gain of this protein function loses its significance in the defense response. Discussion. We demonstrate how structural data can be incorporated in the pipeline of proteomic data analysis prior to making inferences on the importance of individual proteins to plant defense mechanisms. We expect CHURNER to be applicable to any proteomic data set. PMID:27257535

  17. Promiscuous Diffusible Signal Factor Production and Responsiveness of the Xylella fastidiosa Rpf System.

    PubMed

    Ionescu, Michael; Yokota, Kenji; Antonova, Elena; Garcia, Angelica; Beaulieu, Ellen; Hayes, Terry; Iavarone, Anthony T; Lindow, Steven E

    2016-07-19

    Cell density-dependent regulation of gene expression in Xylella fastidiosa that is crucial to its switching between plant hosts and insect vectors is dependent on RpfF and its production of 2-enoic acids known as diffusible signal factor (DSF). We show that X. fastidiosa produces a particularly large variety of similar, relatively long-chain-length 2-enoic acids that are active in modulating gene expression. Both X. fastidiosa itself and a Pantoea agglomerans surrogate host harboring X. fastidiosa RpfF (XfRpfF) is capable of producing a variety of both saturated and unsaturated free fatty acids. However, only 2-cis unsaturated acids were found to be biologically active in X. fastidiosa X. fastidiosa produces, and is particularly responsive to, a novel DSF species, 2-cis-hexadecanoic acid that we term XfDSF2. It is also responsive to other, even longer 2-enoic acids to which other taxa such as Xanthomonas campestris are unresponsive. The 2-enoic acids that are produced by X. fastidiosa are strongly affected by the cellular growth environment, with XfDSF2 not detected in culture media in which 2-tetradecenoic acid (XfDSF1) had previously been found. X. fastidiosa is responsive to much lower concentrations of XfDSF2 than XfDSF1. Apparently competitive interactions can occur between various saturated and unsaturated fatty acids that block the function of those agonistic 2-enoic fatty acids. By altering the particular 2-enoic acids produced and the relative balance of free enoic and saturated fatty acids, X. fastidiosa might modulate the extent of DSF-mediated quorum sensing. X. fastidiosa, having a complicated lifestyle in which it moves and multiplies within plants but also must be vectored by insects, utilizes DSF-based quorum sensing to partition the expression of traits needed for these two processes within different cells in this population based on local cellular density. The finding that it can produce a variety of DSF species in a strongly

  18. Recent Evolutionary Radiation and Host Plant Specialization in the Xylella fastidiosa Subspecies Native to the United States

    PubMed Central

    Vickerman, Danel B.; Bromley, Robin E.; Russell, Stephanie A.; Hartman, John R.; Morano, Lisa D.; Stouthamer, Richard

    2013-01-01

    The bacterial pathogen, Xylella fastidiosa, infects many plant species in the Americas, making it a good model for investigating the genetics of host adaptation. We used multilocus sequence typing (MLST) to identify isolates of the native U.S. subsp. multiplex that were largely unaffected by intersubspecific homologous recombination (IHR) and to investigate how their evolutionary history influences plant host specialization. We identified 110 “non-IHR” isolates, 2 minimally recombinant “intermediate” ones (including the subspecific type), and 31 with extensive IHR. The non-IHR and intermediate isolates defined 23 sequence types (STs) which we used to identify 22 plant hosts (73% trees) characteristic of the subspecies. Except for almond, subsp. multiplex showed no host overlap with the introduced subspecies (subspecies fastidiosa and sandyi). MLST sequences revealed that subsp. multiplex underwent recent radiation (<25% of subspecies age) which included only limited intrasubspecific recombination (ρ/θ = 0.02); only one isolated lineage (ST50 from ash) was older. A total of 20 of the STs grouped into three loose phylogenetic clusters distinguished by nonoverlapping hosts (excepting purple leaf plum): “almond,” “peach,” and “oak” types. These host differences were not geographical, since all three types also occurred in California. ST designation was a good indicator of host specialization. ST09, widespread in the southeastern United States, only infected oak species, and all peach isolates were ST10 (from California, Florida, and Georgia). Only ST23 had a broad host range. Hosts of related genotypes were sometimes related, but often host groupings crossed plant family or even order, suggesting that phylogenetically plastic features of hosts affect bacterial pathogenicity. PMID:23354698

  19. Recent evolutionary radiation and host plant specialization in the Xylella fastidiosa subspecies native to the United States.

    PubMed

    Nunney, Leonard; Vickerman, Danel B; Bromley, Robin E; Russell, Stephanie A; Hartman, John R; Morano, Lisa D; Stouthamer, Richard

    2013-04-01

    The bacterial pathogen, Xylella fastidiosa, infects many plant species in the Americas, making it a good model for investigating the genetics of host adaptation. We used multilocus sequence typing (MLST) to identify isolates of the native U.S. subsp. multiplex that were largely unaffected by intersubspecific homologous recombination (IHR) and to investigate how their evolutionary history influences plant host specialization. We identified 110 "non-IHR" isolates, 2 minimally recombinant "intermediate" ones (including the subspecific type), and 31 with extensive IHR. The non-IHR and intermediate isolates defined 23 sequence types (STs) which we used to identify 22 plant hosts (73% trees) characteristic of the subspecies. Except for almond, subsp. multiplex showed no host overlap with the introduced subspecies (subspecies fastidiosa and sandyi). MLST sequences revealed that subsp. multiplex underwent recent radiation (<25% of subspecies age) which included only limited intrasubspecific recombination (ρ/θ = 0.02); only one isolated lineage (ST50 from ash) was older. A total of 20 of the STs grouped into three loose phylogenetic clusters distinguished by nonoverlapping hosts (excepting purple leaf plum): "almond," "peach," and "oak" types. These host differences were not geographical, since all three types also occurred in California. ST designation was a good indicator of host specialization. ST09, widespread in the southeastern United States, only infected oak species, and all peach isolates were ST10 (from California, Florida, and Georgia). Only ST23 had a broad host range. Hosts of related genotypes were sometimes related, but often host groupings crossed plant family or even order, suggesting that phylogenetically plastic features of hosts affect bacterial pathogenicity.

  20. Direct evidence of egestion and salivation of Xylella fastidiosa suggests sharpshooters can be “flying syringes”

    USDA-ARS?s Scientific Manuscript database

    Despite nearly 70 years of research, the inoculation mechanism of Xylella fastidiosa by its sharpshooter vectors is still unproven. X. fastidiosa is unique among insect-transmitted plant pathogens because it does not circulate in the vector’s hemolymph, yet it is propagative because it adheres to an...

  1. Multiple, stochastic factors can determine acquisition success of the foregut-borne bacterium, Xylella fastidiosa, by a sharpshooter vector

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a phytopathogenic foregut-borne bacterium whose vectors are sharpshooter leafhoppers. Despite several decades of study, the mechanisms of transmission (acquisition and inoculation) of X. fastidiosa still are not fully understood. Studies of the inoculation mechanism depend upon...

  2. Evaluation of assembling methods on determination of whole genome sequence of Xylella fastidiosa blueberry bacterial leaf scorch strain

    USDA-ARS?s Scientific Manuscript database

    Blueberry bacterial leaf scorch (BBLS) disease, a threat to blueberry production in the Southern USA and potentially elsewhere, is caused by Xylella fastidiosa. Efficient control of BBLS requires knowledge of the pathogen. However, this is challenging because Xylella fastidiosa is difficult to cultu...

  3. The chemotaxis regulator pilG of Xylella fastidiosa is required for virulence in Vitis vinifera grapevines

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a Gram-negative, xylem-limited pathogenic bacterium that causes Pierce’s disease of grapevines. Type IV pili of X. fastidiosa are regulated by pilG, a chemotaxis regulator in Pil-Chp operon involving signal transduction pathways. To elucidate the role of pilG in twitching motil...

  4. The chemotaxis regulator pilG of Xylella fastidiosa is required for virulence in Vitis vinifera grapevines

    USDA-ARS?s Scientific Manuscript database

    Type IV pili of X. fastidiosa are regulated by pilG, a response regulator protein putatively involved in chemotaxis-like operon sensing stimuli through signal transduction pathways. To elucidate roles of pilG in pathogenicity of X. fastidiosa, the pilG-deletion mutant and complementary strain contai...

  5. Effects of Insect Origin, Gender, and Age on Transmission of Xylella fastidiosa to Grapevines by Homalodisca vitripennis (Hemiptera: Cicadellidae)

    USDA-ARS?s Scientific Manuscript database

    Homalodisca vitripennis (Germar) is an invasive insect vector in California, where it transmits the bacterium Xylella fastidiosa to grapevines and other crops. Transmission efficiency of X. fastidiosa to grapevines by male and female H. vitripennis originating from two geographically separated popul...

  6. Whole genome sequencing and analyses of Xylella fastidiosa subsp. fastidiosa strain GV156 causing Pierce’s disease of grapevine in Taiwan

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a nutritionally fastidious Gram-negative bacterium causing Pierce’s disease (PD) of grapevines. PD was first reported in Anaheim, California in 1892 and is currently endemic in California and the southeastern U.S. PD also was found outside the U.S. but is limited to the America...

  7. N-acetylcysteine in agriculture, a novel use for an old molecule: focus on controlling the plant-pathogen Xylella fastidiosa.

    PubMed

    Muranaka, Lígia S; Giorgiano, Thais E; Takita, Marco A; Forim, Moacir R; Silva, Luis F C; Coletta-Filho, Helvécio D; Machado, Marcos A; de Souza, Alessandra A

    2013-01-01

    Xylella fastidiosa is a plant pathogen bacterium that causes diseases in many different crops. In citrus, it causes Citrus Variegated Chlorosis (CVC). The mechanism of pathogenicity of this bacterium is associated with its capacity to colonize and form a biofilm in the xylem vessels of host plants, and there is not yet any method to directly reduce populations of this pathogen in the field. In this study, we investigated the inhibitory effect of N-Acetylcysteine (NAC), a cysteine analogue used mainly to treat human diseases, on X. fastidiosa in different experimental conditions. Concentrations of NAC over 1 mg/mL reduced bacterial adhesion to glass surfaces, biofilm formation and the amount of exopolysaccharides (EPS). The minimal inhibitory concentration of NAC was 6 mg/mL. NAC was supplied to X. fastidiosa-infected plants in hydroponics, fertigation, and adsorbed to organic fertilizer (NAC-Fertilizer). HPLC analysis indicated that plants absorbed NAC at concentrations of 0.48 and 2.4 mg/mL but not at 6 mg/mL. Sweet orange plants with CVC symptoms treated with NAC (0.48 and 2.4 mg/mL) in hydroponics showed clear symptom remission and reduction in bacterial population, as analyzed by quantitative PCR and bacterial isolation. Experiments using fertigation and NAC-Fertilizer were done to simulate a condition closer to that normally is used in the field. For both, significant symptom remission and a reduced bacterial growth rate were observed. Using NAC-Fertilizer the lag for resurgence of symptoms on leaves after interruption of the treatment increased to around eight months. This is the first report of the anti-bacterial effect of NAC against a phytopathogenic bacterium. The results obtained in this work together with the characteristics of this molecule indicate that the use of NAC in agriculture might be a new and sustainable strategy for controlling plant pathogenic bacteria.

  8. N-Acetylcysteine in Agriculture, a Novel Use for an Old Molecule: Focus on Controlling the Plant–Pathogen Xylella fastidiosa

    PubMed Central

    Muranaka, Lígia S.; Giorgiano, Thais E.; Takita, Marco A.; Forim, Moacir R.; Silva, Luis F. C.; Coletta-Filho, Helvécio D.; Machado, Marcos A.; de Souza, Alessandra A.

    2013-01-01

    Xylella fastidiosa is a plant pathogen bacterium that causes diseases in many different crops. In citrus, it causes Citrus Variegated Chlorosis (CVC). The mechanism of pathogenicity of this bacterium is associated with its capacity to colonize and form a biofilm in the xylem vessels of host plants, and there is not yet any method to directly reduce populations of this pathogen in the field. In this study, we investigated the inhibitory effect of N-Acetylcysteine (NAC), a cysteine analogue used mainly to treat human diseases, on X. fastidiosa in different experimental conditions. Concentrations of NAC over 1 mg/mL reduced bacterial adhesion to glass surfaces, biofilm formation and the amount of exopolysaccharides (EPS). The minimal inhibitory concentration of NAC was 6 mg/mL. NAC was supplied to X. fastidiosa-infected plants in hydroponics, fertigation, and adsorbed to organic fertilizer (NAC-Fertilizer). HPLC analysis indicated that plants absorbed NAC at concentrations of 0.48 and 2.4 mg/mL but not at 6 mg/mL. Sweet orange plants with CVC symptoms treated with NAC (0.48 and 2.4 mg/mL) in hydroponics showed clear symptom remission and reduction in bacterial population, as analyzed by quantitative PCR and bacterial isolation. Experiments using fertigation and NAC-Fertilizer were done to simulate a condition closer to that normally is used in the field. For both, significant symptom remission and a reduced bacterial growth rate were observed. Using NAC-Fertilizer the lag for resurgence of symptoms on leaves after interruption of the treatment increased to around eight months. This is the first report of the anti-bacterial effect of NAC against a phytopathogenic bacterium. The results obtained in this work together with the characteristics of this molecule indicate that the use of NAC in agriculture might be a new and sustainable strategy for controlling plant pathogenic bacteria. PMID:24009716

  9. Radicinin from Cochliobolus sp. inhibits Xylella fastidiosa, the causal agent of Pierce's Disease of grapevine.

    PubMed

    Aldrich, Thomas J; Rolshausen, Philippe E; Roper, M Caroline; Reader, Jordan M; Steinhaus, Matthew J; Rapicavoli, Jeannette; Vosburg, David A; Maloney, Katherine N

    2015-08-01

    The fastidious phytopathogenic bacterium, Xylella fastidiosa, poses a substantial threat to many economically important crops, causing devastating diseases including Pierce's Disease of grapevine. Grapevines (Vitis vinifera L.) planted in an area under Pierce's Disease pressure often display differences in disease severity and symptom expression, with apparently healthy vines growing alongside the dying ones, despite the fact that all the vines are genetic clones of one another. Under the hypothesis that endophytic microbes might be responsible for this non-genetic resistance to X. fastidiosa, endophytic fungi were isolated from vineyard cvs. 'Chardonnay' and 'Cabernet Sauvignon' grown under high Pierce's Disease pressure. A Cochliobolus sp. isolated from a Cabernet Sauvignon grapevine inhibited the growth of X. fastidiosa in vitro. Bioassay-guided isolation of an organic extract of Cochliobolus sp. yielded the natural product radicinin as the major active compound. Radicinin also inhibited proteases isolated from the culture supernatant of X. fastidiosa. In order to assess structure-activity relationships, three semi-synthetic derivatives of radicinin were prepared and tested for activity against X. fastidiosa in vitro. Assay results of these derivatives are consistent with enzyme inactivation by conjugate addition to carbon-10 of radicinin, as proposed previously. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. The diversity of citrus endophytic bacteria and their interactions with Xylella fastidiosa and host plants.

    PubMed

    Azevedo, João Lúcio; Araújo, Welington Luiz; Lacava, Paulo Teixeira

    2016-01-01

    The bacterium Xylella fastidiosa is the causal agent of citrus variegated chlorosis (CVC) and has been associated with important losses in commercial orchards of all sweet orange [Citrus sinensis (L.)] cultivars. The development of this disease depends on the environmental conditions, including the endophytic microbial community associated with the host plant. Previous studies have shown that X. fastidiosa interacts with the endophytic community in xylem vessels as well as in the insect vector, resulting in a lower bacterial population and reduced CVC symptoms. The citrus endophytic bacterium Methylobacterium mesophilicum can trigger X. fastidiosa response in vitro, which results in reduced growth and induction of genes associated with energy production, stress, transport, and motility, indicating that X. fastidiosa has an adaptive response to M. mesophilicum. Although this response may result in reduced CVC symptoms, the colonization rate of the endophytic bacteria should be considered in studies that intend to use this endophyte to suppress CVC disease. Symbiotic control is a new strategy that uses symbiotic endophytes as biological control agents to antagonize or displace pathogens. Candidate endophytes for symbiotic control of CVC must occupy the xylem of host plants and attach to the precibarium of sharpshooter insects to access the pathogen. In the present review, we focus on interactions between endophytic bacteria from sweet orange plants and X. fastidiosa, especially those that may be candidates for control of CVC.

  11. The diversity of citrus endophytic bacteria and their interactions with Xylella fastidiosa and host plants

    PubMed Central

    Azevedo, João Lúcio; Araújo, Welington Luiz; Lacava, Paulo Teixeira

    2016-01-01

    Abstract The bacterium Xylella fastidiosa is the causal agent of citrus variegated chlorosis (CVC) and has been associated with important losses in commercial orchards of all sweet orange [Citrus sinensis (L.)] cultivars. The development of this disease depends on the environmental conditions, including the endophytic microbial community associated with the host plant. Previous studies have shown that X. fastidiosa interacts with the endophytic community in xylem vessels as well as in the insect vector, resulting in a lower bacterial population and reduced CVC symptoms. The citrus endophytic bacterium Methylobacterium mesophilicum can trigger X. fastidiosa response in vitro, which results in reduced growth and induction of genes associated with energy production, stress, transport, and motility, indicating that X. fastidiosa has an adaptive response to M. mesophilicum. Although this response may result in reduced CVC symptoms, the colonization rate of the endophytic bacteria should be considered in studies that intend to use this endophyte to suppress CVC disease. Symbiotic control is a new strategy that uses symbiotic endophytes as biological control agents to antagonize or displace pathogens. Candidate endophytes for symbiotic control of CVC must occupy the xylem of host plants and attach to the precibarium of sharpshooter insects to access the pathogen. In the present review, we focus on interactions between endophytic bacteria from sweet orange plants and X. fastidiosa, especially those that may be candidates for control of CVC. PMID:27727362

  12. Identification of an operon, Pil-Chp, that controls twitching motility and virulence in Xylella fastidiosa.

    PubMed

    Cursino, Luciana; Galvani, Cheryl D; Athinuwat, Dusit; Zaini, Paulo A; Li, Yaxin; De La Fuente, Leonardo; Hoch, Harvey C; Burr, Thomas J; Mowery, Patricia

    2011-10-01

    Xylella fastidiosa is an important phytopathogenic bacterium that causes many serious plant diseases, including Pierce's disease of grapevines. Disease manifestation by X. fastidiosa is associated with the expression of several factors, including the type IV pili that are required for twitching motility. We provide evidence that an operon, named Pil-Chp, with genes homologous to those found in chemotaxis systems, regulates twitching motility. Transposon insertion into the pilL gene of the operon resulted in loss of twitching motility (pilL is homologous to cheA genes encoding kinases). The X. fastidiosa mutant maintained the type IV pili, indicating that the disrupted pilL or downstream operon genes are involved in pili function, and not biogenesis. The mutated X. fastidiosa produced less biofilm than wild-type cells, indicating that the operon contributes to biofilm formation. Finally, in planta the mutant produced delayed and less severe disease, indicating that the Pil-Chp operon contributes to the virulence of X. fastidiosa, presumably through its role in twitching motility.

  13. Differential expression of genes of Xylella fastidiosa in xylem fluid of citrus and grapevine.

    PubMed

    Shi, Xiangyang; Bi, Jianlong; Morse, Joseph G; Toscano, Nick C; Cooksey, Donald A

    2010-03-01

    Xylella fastidiosa causes a serious Pierce's disease (PD) in grapevine. Xylella fastidiosa cells from a PD strain were grown in a pure xylem fluid of a susceptible grapevine cultivar vs. xylem fluid from citrus, which is not a host for this strain of X. fastidiosa. When grown in grapevine xylem fluid, cells of the PD strain formed clumps and biofilm formed to a greater extent than in citrus xylem fluid, although the PD strain did grow in xylem fluid of three citrus varieties. The differential expression of selected genes of a PD X. fastidiosa strain cultured in the two xylem fluids was analyzed using a DNA macroarray. Compared with citrus xylem fluid, grapevine xylem fluid stimulated the expression of X. fastidiosa genes involved in virulence regulation, such as gacA, algU, xrvA, and hsq, and also genes involved in the biogenesis of pili and twitching motility, such as fimT, pilI, pilU, and pilY1. Increased gene expression likely contributes to PD expression in grapevine, whereas citrus xylem fluid did not support or possibly suppressed the expression of these virulence genes.

  14. Directed evolution induces tributyrin hydrolysis in a virulence factor of Xylella fastidiosa using a duplicated gene as a template

    PubMed Central

    Rao, Basuthkar J.; Asgeirsson, Bjarni; Dandekar, Abhaya

    2014-01-01

    Duplication of genes is one of the preferred ways for natural selection to add advantageous functionality to the genome without having to reinvent the wheel with respect to catalytic efficiency and protein stability. The duplicated secretory virulence factors of Xylella fastidiosa (LesA, LesB and LesC), implicated in Pierce's disease of grape and citrus variegated chlorosis of citrus species, epitomizes the positive selection pressures exerted on advantageous genes in such pathogens. A deeper insight into the evolution of these lipases/esterases is essential to develop resistance mechanisms in transgenic plants. Directed evolution, an attempt to accelerate the evolutionary steps in the laboratory, is inherently simple when targeted for loss of function. A bigger challenge is to specify mutations that endow a new function, such as a lost functionality in a duplicated gene. Previously, we have proposed a method for enumerating candidates for mutations intended to transfer the functionality of one protein into another related protein based on the spatial and electrostatic properties of the active site residues (DECAAF). In the current work, we present in vivo validation of DECAAF by inducing tributyrin hydrolysis in LesB based on the active site similarity to LesA. The structures of these proteins have been modeled using RaptorX based on the closely related LipA protein from Xanthomonas oryzae. These mutations replicate the spatial and electrostatic conformation of LesA in the modeled structure of the mutant LesB as well, providing in silico validation before proceeding to the laborious in vivo work. Such focused mutations allows one to dissect the relevance of the duplicated genes in finer detail as compared to gene knockouts, since they do not interfere with other moonlighting functions, protein expression levels or protein-protein interaction. PMID:25717364

  15. 7 CFR 925.4 - Grapes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Grapes. 925.4 Section 925.4 Agriculture Regulations of... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE GRAPES GROWN IN A DESIGNATED AREA OF SOUTHEASTERN CALIFORNIA Definitions § 925.4 Grapes. Grapes means any variety of vinifera species table grapes...

  16. Eudora muscadine grape

    USDA-ARS?s Scientific Manuscript database

    'Eudora', a purple fruited muscadine grape (Vitis rotundifolia Michx.) intended for the fresh market, has been approved for joint release as a public domain cultivar by the University of Florida Experiment Station and the USDA-ARS. ‘Eudora’ ripens in mid-season (late August), is high yielding, and ...

  17. ‘Thomcord’ grape

    USDA-ARS?s Scientific Manuscript database

    Thomcord (Vitis vinifera L. x V. labrusca L.) is a midseason, blue-black seedless table grape that is suitable for farmer’s markets and shipping to domestic markets. It has the aromatic flavor reminiscent of Concord with firmer flesh and skin that adheres to the flesh. It is more suitable to the h...

  18. Transmission of phage by glassy-winged sharpshooters, a vector of Xylella fastidiosa

    PubMed Central

    Bhowmick, Tushar Suvra; Das, Mayukh; Heinz, Kevin M.; Krauter, Peter C.; Gonzalez, Carlos F.

    2016-01-01

    ABSTRACT Xylella fastidiosa subsp. fastidiosa (Xff) is the causal agent of Pierce's Disease (PD) of grapevines and is vectored by the glassy-winged sharpshooter (GWSS, Homalodisca vitripennis). Previously we have reported the development of a bacteriophage (phage) based biocontrol system for PD, but no information on insect transmission of phages has been reported. Here we communicate that laboratory reared GWSSs fed on cowpea plants (Vigna unguiculata subsp. unguiculata) harboring the virulent phage Paz were able to uptake of phage efficiently when the phage was present in high concentration, but were inefficient in transfer to plants. PMID:27738554

  19. The crystal structure of the cysteine protease Xylellain from Xylella fastidiosa reveals an intriguing activation mechanism.

    PubMed

    Leite, Ney Ribeiro; Faro, Aline Regis; Dotta, Maria Amélia Oliva; Faim, Livia Maria; Gianotti, Andreia; Silva, Flavio Henrique; Oliva, Glaucius; Thiemann, Otavio Henrique

    2013-02-14

    Xylella fastidiosa is responsible for a wide range of economically important plant diseases. We report here the crystal structure and kinetic data of Xylellain, the first cysteine protease characterized from the genome of the pathogenic X. fastidiosa strain 9a5c. Xylellain has a papain-family fold, and part of the N-terminal sequence blocks the enzyme active site, thereby mediating protein activity. One novel feature identified in the structure is the presence of a ribonucleotide bound outside the active site. We show that this ribonucleotide plays an important regulatory role in Xylellain enzyme kinetics, possibly functioning as a physiological mediator.

  20. Invasive Threats to the American Homeland

    DTIC Science & Technology

    2004-04-01

    The second example is the glassy-winged sharpshooter, an invasive insect that hosts the bacterium Xylella Fastidiosa. The insect was first de- tected... Xylella Fastidiosa causes Pierce’s Disease in grapes, which infects and kills the grapevine. The glassy-winged sharpshooter transmits and spreads the

  1. Diversity of Endophytic Bacterial Populations and Their Interaction with Xylella fastidiosa in Citrus Plants

    PubMed Central

    Araújo, Welington L.; Marcon, Joelma; Maccheroni, Walter; van Elsas, Jan Dirk; van Vuurde, Jim W. L.; Azevedo, João Lúcio

    2002-01-01

    Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as cultivation-independent techniques. The endophytic communities were assessed in surface-disinfected citrus branches by plating and denaturing gradient gel electrophoresis (DGGE). Dominant isolates were characterized by fatty-acid methyl ester analysis as Bacillus pumilus, Curtobacterium flaccumfaciens, Enterobacter cloacae, Methylobacterium spp. (including Methylobacterium extorquens, M. fujisawaense, M. mesophilicum, M. radiotolerans, and M. zatmanii), Nocardia sp., Pantoea agglomerans, and Xanthomonas campestris. We observed a relationship between CVC symptoms and the frequency of isolation of species of Methylobacterium, the genus that we most frequently isolated from symptomatic plants. In contrast, we isolated C. flaccumfaciens significantly more frequently from asymptomatic plants than from those with symptoms of CVC while P. agglomerans was frequently isolated from tangerine (Citrus reticulata) and sweet-orange (C. sinensis) plants, irrespective of whether the plants were symptomatic or asymptomatic or showed symptoms of CVC. DGGE analysis of 16S rRNA gene fragments amplified from total plant DNA resulted in several bands that matched those from the bacterial isolates, indicating that DGGE profiles can be used to detect some endophytic bacteria of citrus plants. However, some bands had no match with any isolate, suggesting the occurrence of other, nonculturable or as yet uncultured, endophytic bacteria. A specific band with a high G+C ratio was observed only in asymptomatic plants. The higher frequency of C. flaccumfaciens in asymptomatic plants suggests a role for this organism in the resistance of plants to CVC. PMID:12324338

  2. Diversity of endophytic bacterial populations and their interaction with Xylella fastidiosa in citrus plants.

    PubMed

    Araújo, Welington L; Marcon, Joelma; Maccheroni, Walter; Van Elsas, Jan Dirk; Van Vuurde, Jim W L; Azevedo, João Lúcio

    2002-10-01

    Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as cultivation-independent techniques. The endophytic communities were assessed in surface-disinfected citrus branches by plating and denaturing gradient gel electrophoresis (DGGE). Dominant isolates were characterized by fatty-acid methyl ester analysis as Bacillus pumilus, Curtobacterium flaccumfaciens, Enterobacter cloacae, Methylobacterium spp. (including Methylobacterium extorquens, M. fujisawaense, M. mesophilicum, M. radiotolerans, and M. zatmanii), Nocardia sp., Pantoea agglomerans, and Xanthomonas campestris. We observed a relationship between CVC symptoms and the frequency of isolation of species of Methylobacterium, the genus that we most frequently isolated from symptomatic plants. In contrast, we isolated C. flaccumfaciens significantly more frequently from asymptomatic plants than from those with symptoms of CVC while P. agglomerans was frequently isolated from tangerine (Citrus reticulata) and sweet-orange (C. sinensis) plants, irrespective of whether the plants were symptomatic or asymptomatic or showed symptoms of CVC. DGGE analysis of 16S rRNA gene fragments amplified from total plant DNA resulted in several bands that matched those from the bacterial isolates, indicating that DGGE profiles can be used to detect some endophytic bacteria of citrus plants. However, some bands had no match with any isolate, suggesting the occurrence of other, nonculturable or as yet uncultured, endophytic bacteria. A specific band with a high G+C ratio was observed only in asymptomatic plants. The higher frequency of C. flaccumfaciens in asymptomatic plants suggests a role for this organism in the resistance of plants to CVC.

  3. Grape flavonoids and menopausal health.

    PubMed

    Huntley, A L

    2007-12-01

    Grape flavonoids are members of a larger group of plant compounds called polyphenols. Epidemiological evidence relating to the traditional Mediterranean diet, which is high in polyphenols, derived from vegetables and red wine, suggests that dietary polyphenols are of benefit to health and reduce the incidence of cardiovascular disease. Overall, the evidence is promising for the benefit of grape flavonoids in the form of red wine, red grape juice and related preparations for cardiovascular risk factors. There are data to suggest a reduction in platelet activation, inflammation and low-density lipoprotein oxidation, and improvement of endothelial function with grape flavonoids. The evidence for grape flavonoids and renal function, cognition and cancer is less clear. However, it is important to note that much of this research has been carried out in animal and cell models; relatively little work has been done in humans and specifically on the health of menopausal women. There are no general safety concerns with ingestion of grape products. Obviously, consumption of red wine should be within recommended limits and it should be noted that grape juice has high sugar content. Grape flavonoids are also available as a supplement. In conclusion, it is likely that grape flavonoids do benefit the menopausal women. Further research is needed on the mode and dosage of application to maximize these benefits.

  4. Evidence that explains absence of a latent period for Xylella fastidiosa in its sharpshooter vectors

    USDA-ARS?s Scientific Manuscript database

    The glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar), and other sharpshooter (Cicadelline) leafhoppers transmit Xylella fastidiosa (Xf), the causative agent of Pierce’s disease of grapevine and other scorch diseases. Past research has supported that vectors have virtually no late...

  5. Construction of a shuttle vector and transformation of Xylella fastidiosa with plasmid DNA.

    PubMed

    Qin, X; Hartung, J S

    2001-09-01

    We have isolated, cloned, and sequenced a 5823-bp cryptic plasmid from a strain of Xylella fastidiosa. This plasmid encodes five open reading frames (ORF) greater than 400 nucleotides each. ORF 2 encodes a protein with 37% amino acid identity to the replication initiator protein of plasmid pECB2 from Pseudomonas alcaligenes. This RepA protein from X. fastidiosa contains both a leucine zipper and helix turn helix motif characteristic of proteins involved in DNA replication. The sequence 5' of ORF 2 has all of the features characteristic of plasmid origins of replication as well as regulatory elements required for transcription of ORF 2. Open reading frame 2, along with the upstream origin of replication, was cloned as an EcoRI fragment into pUC19 to create a shuttle vector. This construct was introduced into Xylella fastidiosa by electroporation, with selection for carbenicillin resistance. Transformation was verified by both PCR and Southern hybridization experiments. Frequency of transformation was low, but increased ten-fold when the plasmid was grown in X. fastidiosa rather than Escherichia coli prior to transformation. This work represents the first step towards the development of a system for genetic analysis of this important plant pathogen of citrus, grapevines, and other horticultural crops.

  6. Evidence supporting the Egestion-Salivation Hypothesis for inoculation of Xylella fastidiosa by sharpshooter vectors

    USDA-ARS?s Scientific Manuscript database

    Despite more than 70 years of study, the mechanism of inoculation of semipersistent, foregut-borne plant pathogens by their vectors is still unknown. The best model system for these studies is inoculation of the Pierce’s disease bacterium, Xylella fastidiosa (Xf), by vectors such as the glassy-wing...

  7. Draft Genome Sequence of the Xylella fastidiosa CoDiRO Strain

    PubMed Central

    Chiumenti, Michela; Saponari, Maria; Donvito, Giacinto; Italiano, Alessandro; Loconsole, Giuliana; Boscia, Donato; Cariddi, Corrado; Martelli, Giovanni Paolo; Saldarelli, Pasquale

    2015-01-01

    We determined the draft genome sequence of the Xylella fastidiosa CoDiRO strain, which has been isolated from olive plants in southern Italy (Apulia). It is associated with olive quick decline syndrome (OQDS) and characterized by extensive scorching and desiccation of leaves and twigs. PMID:25676759

  8. Xylella fastidiosa plasmid-encoded PemK toxin is an endoribonuclease.

    USDA-ARS?s Scientific Manuscript database

    Stable inheritance of pXF-RIV11 in Xylella fastidiosa is conferred by the pemI/pemK plasmid addiction system. PemK serves as a toxin inhibiting bacterial growth; PemI is the corresponding antitoxin that blocks activity of PemK toxin by direct binding. PemK toxin and PemI antitoxin were over-expre...

  9. Functional characterization of two toxin-antitoxin systems of Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf) encodes multiple toxin-antitoxin (TA) system homologues, including relE/dinJ and mqsR/ygiT. Phylogenetic analyses indicate these two Xf TA systems have distinct evolutionary histories. Comparisons among Xf subspecies/strains reveal TA systems are often embedded in prophage ...

  10. Functional characterization of the role of rpfA in Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa coordinates virulence in grapevines via quorum sensing signal molecules that are regulated and synthesized by the rpf gene cluster (regulation of pathogenicity factors). rpfA encodes aconitate hydratase and could play a regulator role involved in virulence. To elucidate the role o...

  11. Habitat Effects on Population Density and Movement of Insect Vectors of Xylella fastidiosa in California, USA

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa is a xylem-limited bacterium that causes disease in grapevines, almonds, citrus, pear, alfalfa, and many other economically important plants. In California, USA, the bacteria are transmitted by several species of leafhoppers including the cicadellids Draeculacephala minerva Ball a...

  12. Glassy-winged sharpshooter can use a mechanical mechanism to inoculate Xylella fastidiosa into grapevines

    USDA-ARS?s Scientific Manuscript database

    Xylem-feeding leafhoppers such as the glassy-winged sharpshooter, Homalodisca vitripennis (Cicadellidae: Cicadellinae), are thought to inoculate the bacterium Xylella fastidiosa (Xf) from colonies bound to cuticle of the sharpshooter’s functional foregut (precibarium and cibarium). The mechanism of ...

  13. Draft Genome Sequence of 11399, a Transformable Citrus-Pathogenic Strain of Xylella fastidiosa

    PubMed Central

    Niza, Bárbara; Merfa, Marcus V.; Alencar, Valquíria C.; Menegidio, Fabiano B.; Nunes, Luiz R.; Machado, Marcos A.; Takita, Marco A.

    2016-01-01

    The draft genome of Xylella fastidiosa subsp. pauca strain 11399, a transformable citrus-pathogenic strain, is reported here. The 11399 genome size is 2,690,704 bp and has a G+C content of 52.7%. The draft genome of 11399 reveals the absence of four type I restriction-modification system genes. PMID:27738038

  14. Characterization of Xylella fastidiosa gcvR gene required for pathogenicity

    USDA-ARS?s Scientific Manuscript database

    The transcriptional regulator gcvR of Xylella fastidiosa (Xf) is a putative pathogenicity gene. To elucidate the role of gcvR in Pierce's disease (PD) development, mutant Xf'gcvR and complementary Xf'gcvR-C strains were constructed. The genetically modified strains and wild type Xf were inoculated i...

  15. The DinJ/RelE toxin-antitoxin system suppresses virulence in Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa, the causal agent of a number agriculturally important plant diseases, encodes multiple toxin-antitoxin (TA) systems. TA modules consist of a toxin protein co-expressed with a specific antitoxin, and are often acquired through horizontal gene transfer. Antitoxin molecules (RNA or ...

  16. Leafhopper comparative genomics - Identifying similarities and differences across Leafhopper vectors of Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Leafhoppers, (Hemiptera) are considered the second most important group of plant pathogen vectors. Three leafhopper species which transmit Xylella fastidiosa, a plant pathogen of fruit crops, were examined by comparison of the available expressed sequence tags, ~43,400 ESTs (Hunter datasets, Nationa...

  17. Evaluation of Arabidopsis thaliana as a model host for Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    The bacterium Xylella fastidiosa (Xf) causes a number of devastating plant diseases of significant economic impact. To date, progress determining mechanisms of host plant susceptibility, tolerance or resistance has been slow, due in large part to the long generation time and limited available genet...

  18. Development of Arabidopsis thaliana as a model host for Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    The bacterium Xylella fastidiosa (Xf) causes Pierce's disease and a number of other plant diseases of significant economic impact. To date, progress determining mechanisms of host plant susceptibility, tolerance or resistance has been slow, due in large part to the long generation time and limited a...

  19. Extracellular Genomic DNA Mediates Enhancement of Xylella fastidiosa Biofilm Formation in Vitro

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf) produces extracellular DNA in PD3 liquid medium. This extracellular DNA could enhance biofilm formation, a factor in successful establishment of Xf in planta. The relative amounts of extracellular DNA were positively correlated with planktonic growth and biofilm formation in ...

  20. The Glassy-Winged Sharpshooter Vector of Xylella fastidiosa Harbors a Phytoreovirus

    USDA-ARS?s Scientific Manuscript database

    The glassy-winged sharpshooter (GWSS) vector of Xylella fastidiosa harbors a phytoreovirus species designated as Homalodisca vitripennis reovirus (HoVRV). Double-shelled isometric virus particles purified from GWSS adults resembled those observed in thin sections of GWSS salivary glands by transmis...

  1. Whole genome sequence analyses of Xylella fastidiosa PD strains from different geographical regions

    USDA-ARS?s Scientific Manuscript database

    Genome sequences were determined for two Pierce’s disease (PD) causing Xylella fastidiosa (Xf) strains, one from Florida and one from Taiwan. The Florida strain was ATCC 35879, the type of strain used as a standard reference for related taxonomy research. By contrast, the Taiwan strain used was only...

  2. Stable plasmid vectors for complementation of Xylella fastidiosa mutants in planta

    USDA-ARS?s Scientific Manuscript database

    Current understanding of the mechanisms of Pierce’s Disease development has been significantly advanced by molecular genetic studies of the causal agent, Xylella fastidiosa (Xf). Plasmid vectors are an essential tool for studies of bacterial genetics and pathogenesis. However, most commonly used pla...

  3. Draft genome sequence of Xylella fastidiosa supsp. multiplex strain Griffin-1 from Quercus rubra in Georgia

    USDA-ARS?s Scientific Manuscript database

    The draft genome sequence of Xylella fastidiosa subsp. multiplex Strain Griffin-1 isolated from a red oak tree (Quercus rubra) in Georgia, U.S.A. is reported. The bacterium has a genome size of 2,387,314 bp with 51.7% G+C content and comprises 2,903 predicted open reading frames (ORFs), and 50 RNA g...

  4. Utilization of Genomic Variations Among Xylella fastidiosa Strains for Improved Diagnostic Design

    USDA-ARS?s Scientific Manuscript database

    The Gram-negative, xylem-limited phytopathogenic bacterium Xylella fastidiosa causes economically important diseases in grapevine, citrus and many other plant species. Our recent whole genome comparative analysis of the four sequenced strains has identified genomic variation among these strains. The...

  5. Effects of DNA size on transformation and recombination efficiencies in Xylella fastidiosa.

    PubMed

    Kung, Stephanie H; Retchless, Adam C; Kwan, Jessica Y; Almeida, Rodrigo P P

    2013-03-01

    Horizontally transferred DNA acquired through transformation and recombination has the potential to contribute to the diversity and evolution of naturally competent bacteria. However, many different factors affect the efficiency with which DNA can be transformed and recombined. In this study, we determined how the size of both homologous and nonhomologous regions affects transformation and recombination efficiencies in Xylella fastidiosa, a naturally competent generalist pathogen responsible for many emerging plant diseases. Our experimental data indicate that 96 bp of flanking homology is sufficient to initiate recombination, with recombination efficiencies increasing exponentially with the size of the homologous flanking region up to 1 kb. Recombination efficiencies also decreased with the size of the nonhomologous insert, with no recombination detected when 6 kb of nonhomologous DNA was flanked on either side by 1 kb of homologous sequences. Upon analyzing sequenced X. fastidiosa subsp. fastidiosa genomes for evidence of allele conversion, we estimated the mean size of recombination events to be 1,906 bp, with each event modifying, on average, 1.79% of the nucleotides in the recombined region. There is increasing evidence that horizontally acquired genes significantly affect the genetic diversity of X. fastidiosa, and DNA acquired through natural transformation could be a prominent mode of this horizontal transfer.

  6. Effects of plant water stress on vector feeding behaviors that control acquisition and inoculation of Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Feeding behavior by vectors of Xylella fastidiosa (Xf) such as the glassy-winged sharpshooter (GWSS), Homalodisca vitripennis, directly controls Xf transmission (especially acquisition and inoculation). The present study tested whether plant water stress affects vector performance of acquisition an...

  7. Combination Chemoprevention with Grape Antioxidants

    PubMed Central

    Singh, Chandra K.; Siddiqui, Imtiaz A.; El-Abd, Sabah; Mukhtar, Hasan; Ahmad, Nihal

    2016-01-01

    Antioxidant ingredients present in grape have been extensively investigated for their cancer chemopreventive effects. However, much of the work has been done on individual ingredients, especially focusing on resveratrol and quercetin. Phytochemically, whole grape represents a combination of numerous phytonutrients. Limited research has been done on the possible synergistic/additive/antagonistic interactions among the grape constituents. Among these phytochemical constituents of grapes, resveratrol, quercetin, kaempferol, catechin, epicatechin, and anthocyanins (cyanidin and malvidin) constitute more than 70% of the grape polyphenols. Therefore, these have been relatively well-studied for their chemopreventive effects against a variety of cancers. While a wealth of information is available individually on cancer chemopreventive/anti-proliferative effects of resveratrol and quercetin, limited information is available regarding the other major constituents of grape. Studies have also suggested that multiple grape antioxidants, when used in combination, alone or with other agents/drugs show synergistic or additive anti-proliferative response. Based on strong rationale emanating from published studies, it seems probable that a combination of multiple grape-ingredients alone or together with other agents could impart ‘additive synergism’ against cancer. PMID:26829056

  8. Combination chemoprevention with grape antioxidants.

    PubMed

    Singh, Chandra K; Siddiqui, Imtiaz A; El-Abd, Sabah; Mukhtar, Hasan; Ahmad, Nihal

    2016-06-01

    Antioxidant ingredients present in grape have been extensively investigated for their cancer chemopreventive effects. However, much of the work has been done on individual ingredients, especially focusing on resveratrol and quercetin. Phytochemically, whole grape represents a combination of numerous phytonutrients. Limited research has been done on the possible synergistic/additive/antagonistic interactions among the grape constituents. Among these phytochemical constituents of grapes, resveratrol, quercetin, kaempferol, catechin, epicatechin, and anthocyanins (cyanidin and malvidin) constitute more than 70% of the grape polyphenols. Therefore, these have been relatively well studied for their chemopreventive effects against a variety of cancers. While a wealth of information is available individually on cancer chemopreventive/anti-proliferative effects of resveratrol and quercetin, limited information is available regarding the other major constituents of grape. Studies have also suggested that multiple grape antioxidants, when used in combination, alone or with other agents/drugs show synergistic or additive anti-proliferative response. Based on strong rationale emanating from published studies, it seems probable that a combination of multiple grape ingredients alone or together with other agents could impart 'additive synergism' against cancer. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Interaction between endophytic bacteria from citrus plants and the phytopathogenic bacteria Xylella fastidiosa, causal agent of citrus-variegated chlorosis.

    PubMed

    Lacava, P T; Araújo, W L; Marcon, J; Maccheroni, W; Azevedo, J L

    2004-01-01

    To isolate endophytic bacteria and Xylella fastidiosa and also to evaluate whether the bacterial endophyte community contributes to citrus-variegated chlorosis (CVC) status in sweet orange (Citrus sinensis [L.] Osbeck cv. Pera). The presence of Xylella fastidiosa and the population diversity of culturable endophytic bacteria in the leaves and branches of healthy, CVC-asymptomatic and CVC-symptomatic sweet orange plants and in tangerine (Citrus reticulata cv. Blanco) plants were assessed, and the in vitro interaction between endophytic bacteria and X. fastidiosa was investigated. There were significant differences in endophyte incidence between leaves and branches, and among healthy, CVC-asymptomatic and CVC-symptomatic plants. Bacteria identified as belonging to the genus Methylobacterium were isolated only from branches, mainly from those sampled from healthy and diseased plants, from which were also isolated X. fastidiosa. The in vitro interaction experiments indicated that the growth of X. fastidiosa was stimulated by endophytic Methylobacterium extorquens and inhibited by endophytic Curtobacterium flaccumfaciens. This work provides the first evidence of an interaction between citrus endophytic bacteria and X. fastidiosa and suggests a promising approach that can be used to better understand CVC disease.

  10. 7 CFR 925.4 - Grapes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Grapes. 925.4 Section 925.4 Agriculture Regulations of... ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE GRAPES GROWN IN A DESIGNATED AREA OF SOUTHEASTERN CALIFORNIA Definitions § 925.4 Grapes. Grapes means any variety of vinifera species table...

  11. 7 CFR 925.4 - Grapes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Grapes. 925.4 Section 925.4 Agriculture Regulations of... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE GRAPES GROWN IN A DESIGNATED AREA OF SOUTHEASTERN CALIFORNIA Definitions § 925.4 Grapes. Grapes means any variety of vinifera species table...

  12. 7 CFR 925.4 - Grapes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Grapes. 925.4 Section 925.4 Agriculture Regulations of... ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE GRAPES GROWN IN A DESIGNATED AREA OF SOUTHEASTERN CALIFORNIA Definitions § 925.4 Grapes. Grapes means any variety of vinifera species table...

  13. 7 CFR 925.4 - Grapes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Grapes. 925.4 Section 925.4 Agriculture Regulations of... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE GRAPES GROWN IN A DESIGNATED AREA OF SOUTHEASTERN CALIFORNIA Definitions § 925.4 Grapes. Grapes means any variety of vinifera species table...

  14. Starting from grape cultivation.

    PubMed

    Yoshida, A

    1992-06-01

    Rapid population growth can only be stopped by lowering the fertility rate. The UNFPA recommends improving the employment opportunities for women as the single best way of achieving this reduction. An example of this phenomenon is the grape cultivation in the Nordeste (Northeastern) region of Brazil. This area is the poorest part of Brazil and has the highest proportion of indigent people. These people have been deforesting the Amazon in search of a better life. What they have done is sterilize the land and turned a tropical rain forest into a desert. In an effort to reverse this trend, grape cultivation has been introduced in an area called Petrolina. The area is very dry with less than 500 mm of precipitation annually. They do have access to a 5000 square kilometer artificial lake (the largest in the world) and the 3rd largest river in Brazil (the Sao Francisco). In an effort to avoid using agricultural medicines, the vines are fertilized with organic matter created on the farm and little or no pesticides are used since pests do not live in such an arid region. It has taken 20 years of trial and error, but the quality of the grapes is now very high and is competitive on the world market. Because of climate and location, harvesting is done year round which increases the productivity of the land. The farm managers have found that married women make the best workers and have the highest level of productivity. Age at 1st marriage averages 24-25, compared with 15-16 for unemployed women in the same area. The fertility rate averages 50% of that for unemployed women in the same area. Agricultural development offers the best opportunity for the women of developing countries. It can pay a high wage, reduce fertility, and replant desert areas.

  15. Fermentation Rates of Grape Juice

    PubMed Central

    Ough, C. S.; Kunkee, R. E.

    1968-01-01

    Microbiological analysis showed that juices from white grapes had less biotin than juices from red grapes. The biotin content of the juices of some varieties was significantly different from that of other varieties. We did not note any regional effects on the biotin content of the juices. Biotin content of the Cabernet Sauvignon grapes increased significantly with maturity, whereas the biotin content of a white variety did not. The biotin content, with the total nitrogen, can be used to estimate indirectly the yeast growth potential and hence to predict the fermentation rate of the juice. About 84% of the rate variation can be accounted for by the calculated regression equations. PMID:16349801

  16. Optimisation of techniques for quantification of Botrytis cinerea in grape berries and receptacles by quantitative polymerase chain reaction

    USDA-ARS?s Scientific Manuscript database

    Quantitative PCR (qPCR) can be used to detect and monitor pathogen colonization, but early attempts to apply the technology to Botrytis cinerea infection of grape berries have identified limitations to current techniques. In this study, four DNA extraction methods, two grinding methods, two grape or...

  17. An Overview of Stress-Induced Resveratrol Synthesis in Grapes: Perspectives for Resveratrol-Enriched Grape Products.

    PubMed

    Hasan, Mohidul; Bae, Hanhong

    2017-02-14

    Resveratrol is the most important stilbene phytoalexin synthesized naturally or induced in plants, as a part of their defense mechanism. Grapes and their derivative products, including juice and wine, are the most important natural sources of resveratrol, consisting of notably higher amounts than other natural sources like peanuts. Consumption of red wine with its presence of resveratrol explained the "French Paradox". Hence, the demand of resveratrol from grapes is increasing. Moreover, as a natural source of resveratrol, grapes became very important in the nutraceutical industry for their benefits to human health. The accumulation of resveratrol in grape skin, juice, and wine has been found to be induced by the external stimuli: microbial infection, ultrasonication (US) treatment, light-emitting diode (LED), ultra violet (UV) irradiation, elicitors or signaling compounds, macronutrients, and fungicides. Phenylalanine ammonia lyase, cinnamate-4-hydroxylase, coumaroyl-CoA ligase, and stilbene synthase play a key role in the synthesis of resveratrol. The up-regulation of those genes have the positive relationship with the elicited accumulation of resveratrol. In this review, we encapsulate the effect of different external stimuli (biotic and abiotic stresses or signaling compounds) in order to obtain the maximum accumulation of resveratrol in grape skin, leaves, juice, wine, and cell cultures.

  18. Assessment of Injuries Caused by Anastrepha fraterculus (Wied.) (Diptera: Tephritidae) on the Incidence of Bunch Rot Diseases in Table Grape.

    PubMed

    Machota, R; Bortoli, L C; Cavalcanti, F R; Botton, M; Grützmacher, A D

    2016-08-01

    Anastrepha fraterculus (Wied.) is the main insect pest of table grapes (Vitis vinifera) in the Southern Region of Brazil. In this study, we aimed to investigate the effect of fruit puncturing by adult females and larval infestation by A. fraterculus on the occurrence of bunch rot disease in the grape (cultivar "Itália") by evaluating grapes (a) punctured for oviposition by females of A. fraterculus, sterilized in laboratory with novaluron (40 mg L(-1)) and further spray-inoculated separately with Botrytis cinerea (1 × 10(6) conidia mL(-1)), Glomerella cingulata (1 × 10(6) conidia mL(-1)), and bacteria and yeast that cause sour rot (1 × 10(5) cells mL(-1)), (b) grapes punctured for oviposition by non-sterilized females with pathogen spraying, (c) grapes with mechanical wounds and pathogen spraying, (d) grapes with no wounds and with pathogen spraying, (e) grapes punctured for oviposition by A. fraterculus chemically sterilized in laboratory with novaluron, (f) grapes punctured for oviposition by A. fraterculus non-sterilized in laboratory with novaluron, (g) grapes with mechanical wounds, and (h) grapes with no sterilization or pathogen spraying. Our data indicated that the mechanical and oviposition wounds caused by A. fraterculus increased the percentage of grapes infected by B. cinerea, G. cingulata, and microorganisms of acid rot. The grape puncturing by A. fraterculus and the mechanical wound allows the penetration of B. cinerea and microorganisms leading to acid rot. We conclude that the fruit fly A. fraterculus may facilitate phytopathogens penetration leading to bunch rots in the table grape Itália.

  19. A new paradigm for vector inoculation of Xylella fastidiosa: Direct evidence of egestion and salivation supports that sharpshooters can be “flying syringes”

    USDA-ARS?s Scientific Manuscript database

    Despite nearly 70 years of research, the inoculation mechanism of Xylella fastidiosa by its sharpshooter vectors remains unproven. X. fastidiosa is unique among insect-transmitted plant pathogens because it is propagative but non-circulative, adhering to and multiplying on the cuticular lining of th...

  20. Olive “quick decline” in Italy is associated with Xylella fastidiosa, a plant pathogenic bacterium also associated with California olives

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa, the causal agent of Pierce’s Disease on grapevine, has made its first documented entrance to continental Europe, possibly associated with a new disease on olive called “quick decline.” In October 2013, X. fastidiosa was reported in the Puglia region of southern Italy on declining...

  1. Sharpshooters may be “flying syringes:” First direct evidence of mixed egestion and salivation in inoculation of Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Despite nearly 70 years of research, the inoculation mechanism of Xylella fastidiosa by its sharpshooter vectors remains unproven. X. fastidiosa is unique among insect-transmitted plant pathogens because it is propagative but non-circulative, adhering to and multiplying on the cuticular lining of t...

  2. Effect of Thymol and Linalool Fumigation on Postharvest Diseases of Table Grapes

    PubMed Central

    Shin, Mi Ho; Kim, Jin-Hee; Choi, Hyo-Won; Keum, Yoong Soo

    2014-01-01

    Several postharvest diseases of table grapes (Vitis vinifera) occur during storage, and gray mold rot is a particularly severe disease because the causal agent, Botrytis cinerea, grows at temperatures as low as 0℃. Other postharvest diseases, such as those caused by Penicillium spp. and Aspergillus spp., also often lead to deterioration in the quality of table grapes after harvest. The use of plant essential oils such as thymol and linalool, to reduce postharvest diseases in several kinds of fruits, including table grapes and oranges, has received much attention in European countries. However, to the best of our knowledge there has been no report of the use of thymol fumigation to control gray mold in table grapes in Korea. Thymol (30 µg/mL) and linalool (120 µg/mL) significantly inhibited mycelial growth and conidia germination of B. cinerea. The occurrence rate of gray mold rot of B. cinerea and other unknown fungi was significantly reduced by fumigation with 30 µg/mL thymol in several table grape cultivars, such as Campbell early, Muscat Bailey A, Sheridan, and Geobong. In this study, fumigation with 30 µg/mL thymol, had no influence on the sugar content and hardness of grapes, but reduced fungal infection significantly. This suggests that 30 µg/mL thymol could be utilized to reduce deterioration of grapes due to gray mold and other fungal infections during long-term storage. PMID:25346603

  3. Effect of thymol and linalool fumigation on postharvest diseases of table grapes.

    PubMed

    Shin, Mi Ho; Kim, Jin-Hee; Choi, Hyo-Won; Keum, Yoong Soo; Chun, Se Chul

    2014-09-01

    Several postharvest diseases of table grapes (Vitis vinifera) occur during storage, and gray mold rot is a particularly severe disease because the causal agent, Botrytis cinerea, grows at temperatures as low as 0℃. Other postharvest diseases, such as those caused by Penicillium spp. and Aspergillus spp., also often lead to deterioration in the quality of table grapes after harvest. The use of plant essential oils such as thymol and linalool, to reduce postharvest diseases in several kinds of fruits, including table grapes and oranges, has received much attention in European countries. However, to the best of our knowledge there has been no report of the use of thymol fumigation to control gray mold in table grapes in Korea. Thymol (30 µg/mL) and linalool (120 µg/mL) significantly inhibited mycelial growth and conidia germination of B. cinerea. The occurrence rate of gray mold rot of B. cinerea and other unknown fungi was significantly reduced by fumigation with 30 µg/mL thymol in several table grape cultivars, such as Campbell early, Muscat Bailey A, Sheridan, and Geobong. In this study, fumigation with 30 µg/mL thymol, had no influence on the sugar content and hardness of grapes, but reduced fungal infection significantly. This suggests that 30 µg/mL thymol could be utilized to reduce deterioration of grapes due to gray mold and other fungal infections during long-term storage.

  4. Draft Sequencing and Comparative Genomics of Xylella fastidiosa Strains Reveal Novel Biological Insights

    PubMed Central

    Bhattacharyya, Anamitra; Stilwagen, Stephanie; Reznik, Gary; Feil, Helene; Feil, William S.; Anderson, Iain; Bernal, Axel; D'Souza, Mark; Ivanova, Natalia; Kapatral, Vinayak; Larsen, Niels; Los, Tamara; Lykidis, Athanasios; Selkov, Eugene; Walunas, Theresa L.; Purcell, Alexander; Edwards, Rob A.; Hawkins, Trevor; Haselkorn, Robert; Overbeek, Ross; Kyrpides, Nikos C.; Predki, Paul F.

    2002-01-01

    Draft sequencing is a rapid and efficient method for determining the near-complete sequence of microbial genomes. Here we report a comparative analysis of one complete and two draft genome sequences of the phytopathogenic bacterium, Xylella fastidiosa, which causes serious disease in plants, including citrus, almond, and oleander. We present highlights of an in silico analysis based on a comparison of reconstructions of core biological subsystems. Cellular pathway reconstructions have been used to identify a small number of genes, which are likely to reside within the draft genomes but are not captured in the draft assembly. These represented only a small fraction of all genes and were predominantly large and small ribosomal subunit protein components. By using this approach, some of the inherent limitations of draft sequence can be significantly reduced. Despite the incomplete nature of the draft genomes, it is possible to identify several phage-related genes, which appear to be absent from the draft genomes and not the result of insufficient sequence sampling. This region may therefore identify potential host-specific functions. Based on this first functional reconstruction of a phytopathogenic microbe, we spotlight an unusual respiration machinery as a potential target for biological control. We also predicted and developed a new defined growth medium for Xylella. [The sequence data from this study have been submitted to GenBank under accession nos. NC_002723 (X. fastidiosa Almond [Dixon]) and NC_002722 (X. fastidiosa Oleander [Ann-1]). PMID:12368248

  5. Analysis of gene expression in two growth states of Xylella fastidiosa and its relationship with pathogenicity.

    PubMed

    de Souza, Alessandra A; Takita, Marco A; Coletta-Filho, Helvécio D; Caldana, Camila; Goldman, Gustavo H; Yanai, Giane M; Muto, Nair H; de Oliveira, Regina C; Nunes, Luiz R; Machado, Marcos A

    2003-10-01

    Xylella fastidiosa is a plant pathogen responsible for diseases of economically important crops. Although there is considerable disagreement about its mechanism of pathogenicity, blockage of the vessels is one of the most accepted hypotheses. Loss of virulence by this bacterium was observed after serial passages in axenic culture. To confirm the loss of pathogenicity of X. fastidiosa, the causing agent of citrus variegated chlorosis (CVC), freshly-isolated bacteria (first passage [FP] condition) as well as bacteria obtained after 46 passages in axenic culture (several passage [SP] condition) were inoculated into sweet orange and periwinkle plants. Using real time quantitative polymerase chain reaction, we verified that the colonization of FP cells was more efficient for both hosts. The sequence of the complete X. fastidiosa genome allowed the construction of a DNA microarray that was used to investigate the total changes in gene expression associated with the FP condition. Most genes found to be induced in the FP condition were associated with adhesion and probably with adaptation to the host environment. This report represents the first study of the transcriptome of this pathogen, which has recently gained more importance, since the genome of several strains has been either partially or entirely sequenced.

  6. VapD in Xylella fastidiosa Is a Thermostable Protein with Ribonuclease Activity

    PubMed Central

    Mendes, Juliano S.; Santiago, André da S.; Toledo, Marcelo A. S.; Rosselli-Murai, Luciana K.; Favaro, Marianna T. P.; Santos, Clelton A.; Horta, Maria Augusta C.; Crucello, Aline; Beloti, Lilian L.; Romero, Fabian; Tasic, Ljubica; de Souza, Alessandra A.; de Souza, Anete P.

    2015-01-01

    Xylella fastidiosa strain 9a5c is a gram-negative phytopathogen that is the causal agent of citrus variegated chlorosis (CVC), a disease that is responsible for economic losses in Brazilian agriculture. The most well-known mechanism of pathogenicity for this bacterial pathogen is xylem vessel occlusion, which results from bacterial movement and the formation of biofilms. The molecular mechanisms underlying the virulence caused by biofilm formation are unknown. Here, we provide evidence showing that virulence-associated protein D in X. fastidiosa (Xf-VapD) is a thermostable protein with ribonuclease activity. Moreover, protein expression analyses in two X. fastidiosa strains, including virulent (Xf9a5c) and nonpathogenic (XfJ1a12) strains, showed that Xf-VapD was expressed during all phases of development in both strains and that increased expression was observed in Xf9a5c during biofilm growth. This study is an important step toward characterizing and improving our understanding of the biological significance of Xf-VapD and its potential functions in the CVC pathosystem. PMID:26694028

  7. On the role of extracellular polymeric substances during early stages of Xylella fastidiosa biofilm formation.

    PubMed

    Lorite, Gabriela S; de Souza, Alessandra A; Neubauer, Daniel; Mizaikoff, Boris; Kranz, Christine; Cotta, Mônica A

    2013-02-01

    The structural integrity and protection of bacterial biofilms are intrinsically associated with a matrix of extracellular polymeric substances (EPS) produced by the bacteria cells. However, the role of these substances during biofilm adhesion to a surface remains largely unclear. In this study, the influence of EPS on Xylella fastidiosa biofilm formation was investigated. This bacterium is associated with economically important plant diseases; it presents a slow growth rate and thus allows us to pinpoint more precisely the early stages of cell-surface adhesion. Scanning electron microscopy and atomic force microscopy show evidence of EPS production in such early stages and around individual bacteria cells attached to the substrate surface even a few hours after inoculation. In addition, EPS formation was investigated via attenuated total reflectance (ATR) Fourier transform infrared spectroscopy (FTIR). To this end, X. fastidiosa cells were inoculated within an ATR liquid cell assembly. IR-ATR spectra clearly reveal EPS formation already during the early stages of X. fastidiosa biofilm formation, thereby providing supporting evidence for the hypothesis of the relevance of the EPS contribution to the adhesion process.

  8. VapD in Xylella fastidiosa Is a Thermostable Protein with Ribonuclease Activity.

    PubMed

    Mendes, Juliano S; Santiago, André da S; Toledo, Marcelo A S; Rosselli-Murai, Luciana K; Favaro, Marianna T P; Santos, Clelton A; Horta, Maria Augusta C; Crucello, Aline; Beloti, Lilian L; Romero, Fabian; Tasic, Ljubica; de Souza, Alessandra A; de Souza, Anete P

    2015-01-01

    Xylella fastidiosa strain 9a5c is a gram-negative phytopathogen that is the causal agent of citrus variegated chlorosis (CVC), a disease that is responsible for economic losses in Brazilian agriculture. The most well-known mechanism of pathogenicity for this bacterial pathogen is xylem vessel occlusion, which results from bacterial movement and the formation of biofilms. The molecular mechanisms underlying the virulence caused by biofilm formation are unknown. Here, we provide evidence showing that virulence-associated protein D in X. fastidiosa (Xf-VapD) is a thermostable protein with ribonuclease activity. Moreover, protein expression analyses in two X. fastidiosa strains, including virulent (Xf9a5c) and nonpathogenic (XfJ1a12) strains, showed that Xf-VapD was expressed during all phases of development in both strains and that increased expression was observed in Xf9a5c during biofilm growth. This study is an important step toward characterizing and improving our understanding of the biological significance of Xf-VapD and its potential functions in the CVC pathosystem.

  9. The importance of multilocus sequence typing: cautionary tales from the bacterium Xylella fastidiosa.

    PubMed

    Nunney, L; Elfekih, S; Stouthamer, R

    2012-05-01

    Microbial identification methods have evolved rapidly over the last few decades. One such method is multilocus sequence typing (MLST). MLST is a powerful tool for understanding the evolutionary dynamics of pathogens and to gain insight into their genetic diversity. We illustrate the importance of accurate typing by reporting on three problems that have arisen in the study of a single bacterial species, the plant pathogen Xylella fastidiosa. Two of these were particularly serious since they concerned contamination of important research material that has had detrimental consequences for Xylella research: the contamination of DNA used in the sequencing of an X. fastidiosa genome (Ann-1) with DNA from another X. fastidiosa strain, and the unrecognized mislabeling of a strain (Temecula1) distributed from a culture collection (ATCC). We advocate the routine use of MLST to define strains maintained in culture collections and emphasize the importance of confirming the purity of DNA submitted for sequencing. We also present a third example that illustrates the value of MLST in guiding the choice of taxonomic types. Beyond these situations, there is a strong case for MLST whenever an isolate is used experimentally, especially where genotypic differences are suspected to influence the outcome.

  10. Genome-wide comparison and taxonomic relatedness of multiple Xylella fastidiosa strains reveal the occurrence of three subspecies and a new Xylella species.

    PubMed

    Marcelletti, Simone; Scortichini, Marco

    2016-10-01

    A total of 21 Xylella fastidiosa strains were assessed by comparing their genomes to infer their taxonomic relationships. The whole-genome-based average nucleotide identity and tetranucleotide frequency correlation coefficient analyses were performed. In addition, a consensus tree based on comparisons of 956 core gene families, and a genome-wide phylogenetic tree and a Neighbor-net network were constructed with 820,088 nucleotides (i.e., approximately 30-33 % of the entire X. fastidiosa genome). All approaches revealed the occurrence of three well-demarcated genetic clusters that represent X. fastidiosa subspecies fastidiosa, multiplex and pauca, with the latter appeared to diverge. We suggest that the proposed but never formally described subspecies 'sandyi' and 'morus' are instead members of the subspecies fastidiosa. These analyses support the view that the Xylella strain isolated from Pyrus pyrifolia in Taiwan is likely to be a new species. A widely used multilocus sequence typing analysis yielded conflicting results.

  11. Calcium-Enhanced Twitching Motility in Xylella fastidiosa Is Linked to a Single PilY1 Homolog

    PubMed Central

    Cruz, Luisa F.; Parker, Jennifer K.; Cobine, Paul A.

    2014-01-01

    The plant-pathogenic bacterium Xylella fastidiosa is restricted to the xylem vessel environment, where mineral nutrients are transported through the plant host; therefore, changes in the concentrations of these elements likely impact the growth and virulence of this bacterium. Twitching motility, dependent on type IV pili (TFP), is required for movement against the transpiration stream that results in basipetal colonization. We previously demonstrated that calcium (Ca) increases the motility of X. fastidiosa, although the mechanism was unknown. PilY1 is a TFP structural protein recently shown to bind Ca and to regulate twitching and adhesion in bacterial pathogens of humans. Sequence analysis identified three pilY1 homologs in X. fastidiosa (PD0023, PD0502, and PD1611), one of which (PD1611) contains a Ca-binding motif. Separate deletions of PD0023 and PD1611 resulted in mutants that still showed twitching motility and were not impaired in attachment or biofilm formation. However, the response of increased twitching at higher Ca concentrations was lost in the pilY1-1611 mutant. Ca does not modulate the expression of any of the X. fastidiosa PilY1 homologs, although it increases the expression of the retraction ATPase pilT during active movement. The evidence presented here suggests functional differences between the PilY1 homologs, which may provide X. fastidiosa with an adaptive advantage in environments with high Ca concentrations, such as xylem sap. PMID:25217013

  12. Calcium-Enhanced Twitching Motility in Xylella fastidiosa Is Linked to a Single PilY1 Homolog.

    PubMed

    Cruz, Luisa F; Parker, Jennifer K; Cobine, Paul A; De La Fuente, Leonardo

    2014-12-01

    The plant-pathogenic bacterium Xylella fastidiosa is restricted to the xylem vessel environment, where mineral nutrients are transported through the plant host; therefore, changes in the concentrations of these elements likely impact the growth and virulence of this bacterium. Twitching motility, dependent on type IV pili (TFP), is required for movement against the transpiration stream that results in basipetal colonization. We previously demonstrated that calcium (Ca) increases the motility of X. fastidiosa, although the mechanism was unknown. PilY1 is a TFP structural protein recently shown to bind Ca and to regulate twitching and adhesion in bacterial pathogens of humans. Sequence analysis identified three pilY1 homologs in X. fastidiosa (PD0023, PD0502, and PD1611), one of which (PD1611) contains a Ca-binding motif. Separate deletions of PD0023 and PD1611 resulted in mutants that still showed twitching motility and were not impaired in attachment or biofilm formation. However, the response of increased twitching at higher Ca concentrations was lost in the pilY1-1611 mutant. Ca does not modulate the expression of any of the X. fastidiosa PilY1 homologs, although it increases the expression of the retraction ATPase pilT during active movement. The evidence presented here suggests functional differences between the PilY1 homologs, which may provide X. fastidiosa with an adaptive advantage in environments with high Ca concentrations, such as xylem sap.

  13. A Temperature-Independent Cold-Shock Protein Homolog Acts as a Virulence Factor in Xylella fastidiosa.

    PubMed

    Burbank, Lindsey P; Stenger, Drake C

    2016-05-01

    Xylella fastidiosa, causal agent of Pierce's disease (PD) of grapevine, is a fastidious organism that requires very specific conditions for replication and plant colonization. Cold temperatures reduce growth and survival of X. fastidiosa both in vitro and in planta. However, little is known regarding physiological responses of X. fastidiosa to temperature changes. Cold-shock proteins (CSP), a family of nucleic acid-binding proteins, act as chaperones facilitating translation at low temperatures. Bacterial genomes often encode multiple CSP, some of which are strongly induced following exposure to cold. Additionally, CSP contribute to the general stress response through mRNA stabilization and posttranscriptional regulation. A putative CSP homolog (Csp1) with RNA-binding activity was identified in X. fastidiosa Stag's Leap. The csp1 gene lacked the long 5' untranslated region characteristic of cold-inducible genes and was expressed in a temperature-independent manner. As compared with the wild type, a deletion mutant of csp1 (∆csp1) had decreased survival rates following cold exposure and salt stress in vitro. The deletion mutant also was significantly less virulent in grapevine, as compared with the wild type, in the absence of cold stress. These results suggest an important function of X. fastidiosa Csp1 in response to cellular stress and during plant colonization.

  14. Genome-wide identification, evolutionary and expression analysis of the aspartic protease gene superfamily in grape

    PubMed Central

    2013-01-01

    Background Aspartic proteases (APs) are a large family of proteolytic enzymes found in almost all organisms. In plants, they are involved in many biological processes, such as senescence, stress responses, programmed cell death, and reproduction. Prior to the present study, no grape AP gene(s) had been reported, and their research on woody species was very limited. Results In this study, a total of 50 AP genes (VvAP) were identified in the grape genome, among which 30 contained the complete ASP domain. Synteny analysis within grape indicated that segmental and tandem duplication events contributed to the expansion of the grape AP family. Additional analysis between grape and Arabidopsis demonstrated that several grape AP genes were found in the corresponding syntenic blocks of Arabidopsis, suggesting that these genes arose before the divergence of grape and Arabidopsis. Phylogenetic relationships of the 30 VvAPs with the complete ASP domain and their Arabidopsis orthologs, as well as their gene and protein features were analyzed and their cellular localization was predicted. Moreover, expression profiles of VvAP genes in six different tissues were determined, and their transcript abundance under various stresses and hormone treatments were measured. Twenty-seven VvAP genes were expressed in at least one of the six tissues examined; nineteen VvAPs responded to at least one abiotic stress, 12 VvAPs responded to powdery mildew infection, and most of the VvAPs responded to SA and ABA treatments. Furthermore, integrated synteny and phylogenetic analysis identified orthologous AP genes between grape and Arabidopsis, providing a unique starting point for investigating the function of grape AP genes. Conclusions The genome-wide identification, evolutionary and expression analyses of grape AP genes provide a framework for future analysis of AP genes in defining their roles during stress response. Integrated synteny and phylogenetic analyses provide novel insight into the

  15. Grape Juice: Same Heart Benefits as Wine?

    MedlinePlus

    ... Grapes are rich in health-protecting antioxidants, including resveratrol and flavonoids. These antioxidants are found mainly in ... grapes. Likewise, the level of antioxidants, such as resveratrol found in wine, varies with higher levels in ...

  16. Population Structure of Xylella fastidiosa Associated with Almond Leaf Scorch Disease in the San Joaquin Valley of California.

    PubMed

    Lin, Hong; Islam, Md Sajedul; Cabrera-La Rosa, Juan C; Civerolo, Edwin L; Groves, Russell L

    2015-06-01

    Xylella fastidiosa causes disease in many commercial crops, including almond leaf scorch (ALS) disease in susceptible almond (Prunus dulcis). In this study, genetic diversity and population structure of X. fastidiosa associated with ALS disease were evaluated. Isolates obtained from two almond orchards in Fresno and Kern County in the San Joaquin Valley of California were analyzed for two successive years. Multilocus simple-sequence repeat (SSR) analysis revealed two major genetic clusters that were associated with two host cultivars, 'Sonora' and 'Nonpareil', respectively, regardless of the year of study or location of the orchard. These relationships suggest that host cultivar selection and adaptation are major driving forces shaping ALS X. fastidiosa population structure in the San Joaquin Valley. This finding will provide insight into understanding pathogen adaptation and host selection in the context of ALS disease dynamics.

  17. Crystal structure of a small heat-shock protein from Xylella fastidiosa reveals a distinct high-order structure.

    PubMed

    Fonseca, Emanuella Maria Barreto; Scorsato, Valéria; Dos Santos, Marcelo Leite; Júnior, Atilio Tomazini; Tada, Susely Ferraz Siqueira; Dos Santos, Clelton Aparecido; de Toledo, Marcelo Augusto Szymanski; de Souza, Anete Pereira; Polikarpov, Igor; Aparicio, Ricardo

    2017-04-01

    Citrus variegated chlorosis is a disease that attacks economically important citrus plantations and is caused by the plant-pathogenic bacterium Xylella fastidiosa. In this work, the structure of a small heat-shock protein from X. fastidiosa (XfsHSP17.9) is reported. The high-order structures of small heat-shock proteins from other organisms are arranged in the forms of double-disc, hollow-sphere or spherical assemblies. Unexpectedly, the structure reported here reveals a high-order architecture forming a nearly square cavity.

  18. Multiplexed lateral flow microarray assay for detection of citrus pathogens Xylella fastidiosa and Xanthomonas axonopodis pv citri

    SciTech Connect

    Cary,; Bruce, R; Stubben, Christopher J

    2011-03-22

    The invention provides highly sensitive and specific assays for the major citrus pathogens Xylella fastidiosa and Xanthomonas axonopodis, including a field deployable multiplexed assay capable of rapidly assaying for both pathogens simultaneously. The assays are directed at particular gene targets derived from pathogenic strains that specifically cause the major citrus diseases of citrus variegated chlorosis (Xylella fastidiosa 9a5c) and citrus canker (Xanthomonas axonopodis pv citri). The citrus pathogen assays of the invention offer femtomole sensitivity, excellent linear dynamic range, and rapid and specific detection.

  19. Natural Competence of Xylella fastidiosa Occurs at a High Frequency Inside Microfluidic Chambers Mimicking the Bacterium's Natural Habitats

    PubMed Central

    Kandel, Prem P.; Lopez, Samantha M.; Almeida, Rodrigo P. P.

    2016-01-01

    ABSTRACT Xylella fastidiosa is a xylem-limited bacterium that is the causal agent of emerging diseases in a number of economically important crops. Genetic diversity studies have demonstrated homologous recombination occurring among X. fastidiosa strains, which has been proposed to contribute to host plant shifts. Moreover, experimental evidence confirmed that X. fastidiosa is naturally competent for recombination in vitro. Here, as an approximation of natural habitats (plant xylem vessels and insect mouthparts), recombination was studied in microfluidic chambers (MCs) filled with media amended with grapevine xylem sap. First, different media were screened for recombination in solid agar plates using a pair of X. fastidiosa strains that were previously reported to recombine in coculture. The highest frequency of recombination was obtained with PD3 medium, compared to those with the other two media (X. fastidiosa medium [XFM] and periwinkle wilt [PW] medium) used in previous studies. Dissection of the media components led to the identification of bovine serum albumin as an inhibitor of recombination that was correlated to its previously known effect on inhibition of twitching motility. When recombination was performed in liquid culture, the frequencies were significantly higher under flow conditions (MCs) than under batch conditions (test tubes). The recombination frequencies in MCs and agar plates were not significantly different from each other. Grapevine xylem sap from both susceptible and tolerant varieties allowed high recombination frequency in MCs when mixed with PD3. These results suggest that X. fastidiosa has the ability to be naturally competent in the natural growth environment of liquid flow, and this phenomenon could have implications in X. fastidiosa environmental adaptation. IMPORTANCE Xylella fastidiosa is a plant pathogen that lives inside xylem vessels (where water and nutrients are transported inside the plant) and the mouthparts of insect

  20. Biological Activities of Polyphenols from Grapes

    PubMed Central

    Xia, En-Qin; Deng, Gui-Fang; Guo, Ya-Jun; Li, Hua-Bin

    2010-01-01

    The dietary consumption of grape and its products is associated with a lower incidence of degenerative diseases such as cardiovascular disease and certain types of cancers. Most recent interest has focused on the bioactive phenolic compounds in grape. Anthocyanins, flavanols, flavonols and resveratrol are the most important grape polyphenols because they possess many biological activities, such as antioxidant, cardioprotective, anticancer, anti-inflammation, antiaging and antimicrobial properties. This review summarizes current knowledge on the bioactivities of grape phenolics. The extraction, isolation and identification methods of polyphenols from grape as well as their bioavailability and potential toxicity also are included. PMID:20386657

  1. Grape phytochemicals and associated health benefits.

    PubMed

    Yang, Jun; Xiao, Yang-Yu

    2013-01-01

    The phytochemicals present in fruits and vegetables may play an important role in deceasing chronic disease risk. Grapes, one of the most popular and widely cultivated and consumed fruits in the world, are rich in phytochemicals. Epidemiological evidence has linked the consumption of grapes with reduced risk of chronic diseases, including certain types of cancer and cardiovascular disease. In vitro and in vivo studies have shown that grapes have strong antioxidant activity, inhibiting cancer cell proliferation and suppressing platelet aggregation, while also lowering cholesterol. Grapes contain a variety of phytochemicals, like phenolic acids, stilbenes, anthocyanins, and proanthocyanidins, all of which are strong antioxidants. The phytochemical composition of grapes, however, varies greatly among different varieties. While extensive research exists, a literature review of the health benefits of grapes and their phytochemicals has not been compiled to summarize this work. The aim of this paper is to critically review the most recent literature regarding the concentrations, biological activities, and mechanisms of grape phytochemicals.

  2. Ultraviolet-C and induced stilbenes control ochratoxigenic Aspergillus in grapes.

    PubMed

    Selma, María V; Freitas, Paula M; Almela, Luis; González-Barrio, Rocío; Espín, Juan Carlos; Suslow, Trevor; Tomás-Barberán, Francisco; Gil, María I

    2008-11-12

    This study investigated the efficacy of ultraviolet-C (254 nm) and induced stilbenes to inhibit Aspergillus carbonarius and Aspergillus tubingensis and control ochratoxin A production in grapes. In addition, the stilbene synthesis as a response to UV-C treatment and to infection of ochratoxigenic Aspergillus was compared. The initial microbial inactivation by a previously optimized UV-C illumination protocol for increasing trans-resveratrol content in grapes (50 W/m (2), 40 cm, 60 s) was similar on undamaged and damaged grapes, achieving 1.2 and 1.3 log conidia/100 g reductions, respectively. After 5 days of storage at 22 degrees C, UV-C treatment and the stilbenes induced by UV-C inhibited ochratoxigenic Aspergillus growth in undamaged grapes. UV-C elicited the biosynthesis of trans-resveratrol, while microbial infection and tissue damage triggered the biosynthesis of trans-piceid. trans-Resveratrol was not synthesized as a consequence of ochratoxigenic Aspergillus contamination. However, when trans-resveratrol was synthesized by UV-C, it contributed to inhibiting the development of ochratoxin A producing aspergilli. Furthermore, UV-C treatment also contributed to decrease ochratoxin A production by ochratoxigenic aspergilli. Therefore, UV-C is a promising emerging technology either for reducing the potential ochratoxigenic risk in grapes, which is of particular interest to the wine industry, and also for increasing trans-resveratrol content of grapes, which would provide an added value to the wine.

  3. Burdock fructooligosaccharide induces fungal resistance in postharvest Kyoho grapes by activating the salicylic acid-dependent pathway and inhibiting browning.

    PubMed

    Sun, Fei; Zhang, Pengying; Guo, Moran; Yu, Wenqian; Chen, Kaoshan

    2013-05-01

    Burdock fructooligosaccharide (BFO) is a natural elicitor from Arcitum lappa. The effects of BFO in controlling postharvest disease in grape, apple, banana, kiwi, citrus, strawberry, and pear were investigated. The disease index, decay percentage, and area under the disease progress curve indicated that BFO has general control effects on postharvest disease of fruits. Kyoho grapes were studied to elucidate the mechanism of BFO in boosting the resistance of grapes to Botrytis cinerea infection. BFO treatment induced upregulation of the npr1, pr1, pal, and sts genes, and inhibited the total phenol content decrease, which activated chitinase and β-1,3-glucanase. These results indicated that the salicylic acid-dependent signalling pathway was induced. The delayed colour change and peroxidase and polyphenoloxidase activity suggested that BFO delayed grape browning. The reduced respiration rate, weight loss, and titratable acidity prolonged the shelf life of postharvest grapes. BFO is a promising elicitor in postharvest disease control.

  4. O Antigen Modulates Insect Vector Acquisition of the Bacterial Plant Pathogen Xylella fastidiosa

    PubMed Central

    Rapicavoli, Jeannette N.; Kinsinger, Nichola; Perring, Thomas M.; Backus, Elaine A.; Shugart, Holly J.; Walker, Sharon

    2015-01-01

    Hemipteran insect vectors transmit the majority of plant pathogens. Acquisition of pathogenic bacteria by these piercing/sucking insects requires intimate associations between the bacterial cells and insect surfaces. Lipopolysaccharide (LPS) is the predominant macromolecule displayed on the cell surface of Gram-negative bacteria and thus mediates bacterial interactions with the environment and potential hosts. We hypothesized that bacterial cell surface properties mediated by LPS would be important in modulating vector-pathogen interactions required for acquisition of the bacterial plant pathogen Xylella fastidiosa, the causative agent of Pierce's disease of grapevines. Utilizing a mutant that produces truncated O antigen (the terminal portion of the LPS molecule), we present results that link this LPS structural alteration to a significant decrease in the attachment of X. fastidiosa to blue-green sharpshooter foreguts. Scanning electron microscopy confirmed that this defect in initial attachment compromised subsequent biofilm formation within vector foreguts, thus impairing pathogen acquisition. We also establish a relationship between O antigen truncation and significant changes in the physiochemical properties of the cell, which in turn affect the dynamics of X. fastidiosa adhesion to the vector foregut. Lastly, we couple measurements of the physiochemical properties of the cell with hydrodynamic fluid shear rates to produce a Comsol model that predicts primary areas of bacterial colonization within blue-green sharpshooter foreguts, and we present experimental data that support the model. These results demonstrate that, in addition to reported protein adhesin-ligand interactions, O antigen is crucial for vector-pathogen interactions, specifically in the acquisition of this destructive agricultural pathogen. PMID:26386068

  5. O antigen modulates insect vector acquisition of the bacterial plant pathogen Xylella fastidiosa.

    PubMed

    Rapicavoli, Jeannette N; Kinsinger, Nichola; Perring, Thomas M; Backus, Elaine A; Shugart, Holly J; Walker, Sharon; Roper, M Caroline

    2015-12-01

    Hemipteran insect vectors transmit the majority of plant pathogens. Acquisition of pathogenic bacteria by these piercing/sucking insects requires intimate associations between the bacterial cells and insect surfaces. Lipopolysaccharide (LPS) is the predominant macromolecule displayed on the cell surface of Gram-negative bacteria and thus mediates bacterial interactions with the environment and potential hosts. We hypothesized that bacterial cell surface properties mediated by LPS would be important in modulating vector-pathogen interactions required for acquisition of the bacterial plant pathogen Xylella fastidiosa, the causative agent of Pierce's disease of grapevines. Utilizing a mutant that produces truncated O antigen (the terminal portion of the LPS molecule), we present results that link this LPS structural alteration to a significant decrease in the attachment of X. fastidiosa to blue-green sharpshooter foreguts. Scanning electron microscopy confirmed that this defect in initial attachment compromised subsequent biofilm formation within vector foreguts, thus impairing pathogen acquisition. We also establish a relationship between O antigen truncation and significant changes in the physiochemical properties of the cell, which in turn affect the dynamics of X. fastidiosa adhesion to the vector foregut. Lastly, we couple measurements of the physiochemical properties of the cell with hydrodynamic fluid shear rates to produce a Comsol model that predicts primary areas of bacterial colonization within blue-green sharpshooter foreguts, and we present experimental data that support the model. These results demonstrate that, in addition to reported protein adhesin-ligand interactions, O antigen is crucial for vector-pathogen interactions, specifically in the acquisition of this destructive agricultural pathogen.

  6. 7 CFR 51.889 - Well developed grapes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Well developed grapes. 51.889 Section 51.889... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.889 Well developed grapes. Well developed grapes means grapes which...

  7. 7 CFR 51.889 - Well developed grapes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Well developed grapes. 51.889 Section 51.889... STANDARDS) United States Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.889 Well developed grapes. Well developed grapes means grapes which are not abnormally small for...

  8. 7 CFR 51.889 - Well developed grapes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Well developed grapes. 51.889 Section 51.889... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.889 Well developed grapes. Well developed grapes means grapes which...

  9. 7 CFR 51.889 - Well developed grapes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Well developed grapes. 51.889 Section 51.889... STANDARDS) United States Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.889 Well developed grapes. Well developed grapes means grapes which are not abnormally small for...

  10. 7 CFR 51.889 - Well developed grapes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Well developed grapes. 51.889 Section 51.889... STANDARDS) United States Standards for Grades of Table Grapes (European or Vinifera Type) 1 Definitions § 51.889 Well developed grapes. Well developed grapes means grapes which are not abnormally small for the...

  11. Characterization of unique and differentially expressed proteins in anthracnose-tolerant Florida hybrid bunch grapes.

    PubMed

    Vasanthaiah, Hemanth K N; Katam, Ramesh; Basha, Sheikh M

    2009-06-01

    Anthracnose is a major disease in Florida hybrid bunch grapes, caused by a fungus viz. Elsinoe ampelina. Florida hybrid bunch grapes are grown in southeastern USA for their superior wine characteristics. However, the effect of anthracnose on grape productivity and wine quality is a major concern to grape growers. Our research is aimed at determining biochemical basis of anthracnose tolerance in Florida hybrid bunch grape. Leaf samples were collected from the plants infected with E. ampelina at different periods and analyzed for differential protein expression using high throughput two-dimensional gel electrophoresis. Among the 32 differentially expressed leaf proteins, two were uniquely expressed in tolerant genotypes in response to E. ampelina infection. These proteins were identified as mitochondrial adenosine triphosphate synthase and glutamine synthetase, which are known to play a major role in carbohydrate metabolism and defense. Several proteins including ribulose 1-5 bisphosphate-carboxylase involved in photosynthesis were found to be suppressed in susceptible genotypes compared to tolerant genotypes following E. ampelina infection. The results indicate that the anthracnose-tolerant genotypes have the ability to up-regulate and induce new proteins upon infection to defend the invasion of the pathogen as well as maintain the normal regulatory processes.

  12. Xylella fastidiosa in rabbiteye blueberry in Louisiana is genetically similar to a strain found in Southern highbush blueberry in Georgia

    USDA-ARS?s Scientific Manuscript database

    During the past ten years, Xylella fastidiosa has been confirmed as a pathogen of Southern highbush blueberry (Vaccinium corymbosum interspecific hybrids) in Georgia and Florida. Recent work in Louisiana has shown that it is also associated with reduced yield and altered fruit quality in ‘Tifblue’ ...

  13. The Egestion-Salivation Hypothesis: Evidence for the role of vector saliva in the inoculation mechanism of Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Despite ca. 40 years of study, the mechanism of inoculation of the Pierce’s Disease bacterium, Xylella fastidiosa (Xf), by vectors such as the glassy-winged sharpshooter (GWSS) is still unknown. Research on the Egestion-Salivation Hypothesis for Xf inoculation will be presented. Two important step...

  14. Support for the salivation-egestion hypothesis for Xylella fastidiosa inoculation: salivary glucanase is injected into xylem during vector feeding.

    USDA-ARS?s Scientific Manuscript database

    The salivation-egestion hypothesis for the inoculation mechanism of Xylella fastidiosa (Xf) proposes that saliva secreted into plants is taken up into the vector’s precibarium. There, saliva loosens the Xf bacterial biofilm by enzymatically degrading ß-1, 4 glucans that form the chemical backbone o...

  15. Effects of plant water stress on vector feeding behaviors that control acquisition and inoculation of Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf) is an economically important pathogen of grapevine (Pierce’s disease), stone fruits, nursery trees, and ornamental plants (various scorch diseases) in California. The bacterium is transmitted by sharpshooter leafhopper vectors, such as the glassy-winged sharpshooter (GWSS),...

  16. Effects of plant water stress and temperature on glassy-winged sharpshooter feeding in relation to transmission of Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    The glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar), is an economically important pest of grapevine, stone fruits, nursery trees, and ornamental plants in California because it transmits Xylella fastidiosa (Xf). Two related studies examined whether GWSS feeding behaviors that co...

  17. De Novo whole genome sequence of Xylella fastidiosa subsp. multiplex strain BB01 from blueberry in Georgia, USA

    USDA-ARS?s Scientific Manuscript database

    This study reports a de novo assembled draft genome sequence of Xylella fastidiosa subsp. multiplex strain BB01 causing blueberry bacterial leaf scorch in Georgia, USA. The BB01 genome is 2,517,579 bp with a G+C content of 51.8% and 2,943 open reading frames (ORFs) and 48 RNA genes....

  18. Toxin-antitoxin systems mqsR/ygiT and dinJ/RelE of Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    The plant pathogen Xylella fastidiosa (Xf) encodes multiple toxin-antitoxin (TA) system homologues, including relE/dinJ and mqsR/ygiT. Phylogenetic analyses indicate these two Xf TA systems have distinct evolutionary histories. Genomic comparisons among Xf subspecies/strains reveal TA systems are ...

  19. Plasmid transfer by conjugation as a possible route of horizontal gene transfer and recombination in Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Horizontal gene transfer is an important component of evolution and adaptation of bacterial species. Xylella fastidiosa has the ability to incorporate exogenous DNA into its genome by homologous recombination at relatively high rates. This genetic recombination is believed to play a role in adaptati...

  20. The distribution and biology of potential vectors of Xylella fastidiosa on coffee and citrus in Puerto Rico

    USDA-ARS?s Scientific Manuscript database

    Plant diseases caused by Xylella fastidiosa (Wells et al.) (Xf) surround the Caribbean Basin. Two major commodities of Puerto Rico, coffee and citrus, are highly susceptible to Xf. We surveyed potential vectors of Xf in coffee and citrus farms in western Puerto Rico over an 18 month period. Cicadel...

  1. Response of Xylella fastidiosa to Zinc: Decreased Culturability, Increased Exopolysaccharide Production, and Formation of Resilient Biofilms under Flow Conditions

    PubMed Central

    Navarrete, Fernando

    2014-01-01

    The bacterial plant pathogen Xylella fastidiosa produces biofilm that accumulates in the host xylem vessels, affecting disease development in various crops and bacterial acquisition by insect vectors. Biofilms are sensitive to the chemical composition of the environment, and mineral elements being transported in the xylem are of special interest for this pathosystem. Here, X. fastidiosa liquid cultures were supplemented with zinc and compared with nonamended cultures to determine the effects of Zn on growth, biofilm, and exopolysaccharide (EPS) production under batch and flow culture conditions. The results show that Zn reduces growth and biofilm production under both conditions. However, in microfluidic chambers under liquid flow and with constant bacterial supplementation (closer to conditions inside the host), a dramatic increase in biofilm aggregates was seen in the Zn-amended medium. Biofilms formed under these conditions were strongly attached to surfaces and were not removed by medium flow. This phenomenon was correlated with increased EPS production in stationary-phase cells grown under high Zn concentrations. Zn did not cause greater adhesion to surfaces by individual cells. Additionally, viability analyses suggest that X. fastidiosa may be able to enter the viable but nonculturable state in vitro, and Zn can hasten the onset of this state. Together, these findings suggest that Zn can act as a stress factor with pleiotropic effects on X. fastidiosa and indicate that, although Zn could be used as a bactericide treatment, it could trigger the undesired effect of stronger biofilm formation upon reinoculation events. PMID:24271184

  2. CHARACTERIZATION AND IDENTIFICATION OF PD RESISTANCE MECHANISMS: ANALYSES OF XYLEM ANATOMICAL STRUCTURES AND MOLECULAR INTERACTIONS OF HOST/XYLELLA FASTIDIOSA

    USDA-ARS?s Scientific Manuscript database

    The xylem-limited bacterium Xylella fastidiosa (Xf) causes Pierce’s disease (PD) with symptoms primarily due to xylem vessel blockage in susceptible grapevines. Virulence may be related to pathogen titer, presence or absence of chemical compounds in xylem sap, and/or anatomical features of the xylem...

  3. Plasmid vectors for Xylella fastidiosa utilizing a toxin-antitoxin system for plasmid stability in the absence of antibiotic selection

    USDA-ARS?s Scientific Manuscript database

    The phytopathogen Xylella fastidiosa causes disease in a variety of important crop and landscape plants. Functional genetic studies have led to a broader understanding of virulence mechanisms used by this pathogen in the grapevine host. Plasmid shuttle vectors are important tools in studies of bacte...

  4. Population structure of Xylella fastidiosa associated with almond leaf scorch disease in the San Joaquin Valley of California

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf) causes disease in many commercial crops including almond leaf scorch (ALS) disease in susceptible almond (Prunus dulcis). In this study, genetic diversity and population structure of Xf associated with ALS disease were evaluated. Strains isolated from two almond production si...

  5. Plasmid Vectors for Xylella fastidiosa Utilizing a Toxin-Antitoxin System for Stability in the Absence of Antibiotic Selection.

    PubMed

    Burbank, Lindsey P; Stenger, Drake C

    2016-08-01

    The phytopathogen Xylella fastidiosa causes disease in a variety of important crop and landscape plants. Functional genetic studies have led to a broader understanding of virulence mechanisms used by this pathogen in the grapevine host. Plasmid shuttle vectors are important tools in studies of bacterial genetics but there are only a limited number of plasmid vectors available that replicate in X. fastidiosa, and even fewer that are retained without antibiotic selection. Two plasmids are described here that show stable replication in X. fastidiosa and are effective for gene complementation both in vitro and in planta. Plasmid maintenance is facilitated by incorporation of the PemI/PemK plasmid addiction system, consisting of PemK, an endoribonuclease toxin, and its cognate antitoxin, PemI. Vector pXf20pemIK utilizes a native X. fastidiosa replication origin as well as a high-copy-number pUC origin for propagation in Escherichia coli cloning strains. Broad-host-range vector pBBR5pemIK is a medium- to low-copy-number plasmid based on the pBBR1 backbone. Both plasmids are maintained for extended periods of time in the absence of antibiotic selection, as well as up to 14 weeks in grapevine, without affecting bacterial fitness. These plasmids present an alternative to traditional complementation and expression vectors which rely on antibiotic selection for plasmid retention.

  6. Response of Xylella fastidiosa to zinc: decreased culturability, increased exopolysaccharide production, and formation of resilient biofilms under flow conditions.

    PubMed

    Navarrete, Fernando; De La Fuente, Leonardo

    2014-02-01

    The bacterial plant pathogen Xylella fastidiosa produces biofilm that accumulates in the host xylem vessels, affecting disease development in various crops and bacterial acquisition by insect vectors. Biofilms are sensitive to the chemical composition of the environment, and mineral elements being transported in the xylem are of special interest for this pathosystem. Here, X. fastidiosa liquid cultures were supplemented with zinc and compared with nonamended cultures to determine the effects of Zn on growth, biofilm, and exopolysaccharide (EPS) production under batch and flow culture conditions. The results show that Zn reduces growth and biofilm production under both conditions. However, in microfluidic chambers under liquid flow and with constant bacterial supplementation (closer to conditions inside the host), a dramatic increase in biofilm aggregates was seen in the Zn-amended medium. Biofilms formed under these conditions were strongly attached to surfaces and were not removed by medium flow. This phenomenon was correlated with increased EPS production in stationary-phase cells grown under high Zn concentrations. Zn did not cause greater adhesion to surfaces by individual cells. Additionally, viability analyses suggest that X. fastidiosa may be able to enter the viable but nonculturable state in vitro, and Zn can hasten the onset of this state. Together, these findings suggest that Zn can act as a stress factor with pleiotropic effects on X. fastidiosa and indicate that, although Zn could be used as a bactericide treatment, it could trigger the undesired effect of stronger biofilm formation upon reinoculation events.

  7. Structural and Biochemical Characterization of Xylella fastidiosa DsbA Family Members: New insightsinto the Enzyme-Substrate Interaction

    SciTech Connect

    Rinaldi, F.; Meza, A; Gulmarges, B

    2009-01-01

    Disulfide oxidoreductase DsbA catalyzes disulfide bond formation in proteins secreted to the periplasm and has been related to the folding process of virulence factors in many organisms. It is among the most oxidizing of the thioredoxin-like proteins, and DsbA redox power is understood in terms of the electrostatic interactions involving the active site motif CPHC. The plant pathogen Xylella fastidiosa has two chromosomal genes encoding two oxidoreductases belonging to the DsbA family, and in one of them, the canonical motif CPHC is replaced by CPAC. Biochemical assays showed that both X. fastidiosa homologues have similar redox properties and the determination of the crystal structure of XfDsbA revealed substitutions in the active site of X. fastidiosa enzymes, which are proposed to compensate for the lack of the conserved histidine in XfDsbA2. In addition, electron density maps showed a ligand bound to the XfDsbA active site, allowing the characterization of the enzyme interaction with an 8-mer peptide. Finally, surface analysis of XfDsbA and XfDsbA2 suggests that X. fastidiosa enzymes may have different substrate specificities.

  8. Whole genome sequences of two Xylella fastidiosa strains (M12 and M23) causing almond leaf scorch disease in California.

    PubMed

    Chen, J; Xie, G; Han, S; Chertkov, O; Sims, D; Civerolo, E L

    2010-09-01

    Xylella fastidiosa is a Gram-negative plant-pathogenic bacterium causing many economically important diseases, including almond leaf scorch disease (ALSD) in California. Genome information greatly facilitates research on this nutritionally fastidious organism. Here we report the complete genome sequences of two ALSD strains of this bacterium, M12 and M23.

  9. The iron stimulon of Xylella fastidiosa includes genes for type IV pilus and colicin V-like bacteriocins.

    PubMed

    Zaini, Paulo A; Fogaça, Andréa C; Lupo, Fernanda G N; Nakaya, Helder I; Vêncio, Ricardo Z N; da Silva, Aline M

    2008-04-01

    Xylella fastidiosa is the etiologic agent of a wide range of plant diseases, including citrus variegated chlorosis (CVC), a major threat to citrus industry. The genomes of several strains of this phytopathogen were completely sequenced, enabling large-scale functional studies. DNA microarrays representing 2,608 (91.6%) coding sequences (CDS) of X. fastidiosa CVC strain 9a5c were used to investigate transcript levels during growth with different iron availabilities. When treated with the iron chelator 2,2'-dipyridyl, 193 CDS were considered up-regulated and 216 were considered down-regulated. Upon incubation with 100 microM ferric pyrophosphate, 218 and 256 CDS were considered up- and down-regulated, respectively. Differential expression for a subset of 44 CDS was further evaluated by reverse transcription-quantitative PCR. Several CDS involved with regulatory functions, pathogenicity, and cell structure were modulated under both conditions assayed, suggesting that major changes in cell architecture and metabolism occur when X. fastidiosa cells are exposed to extreme variations in iron concentration. Interestingly, the modulated CDS include those related to colicin V-like bacteriocin synthesis and secretion and to functions of pili/fimbriae. We also investigated the contribution of the ferric uptake regulator Fur to the iron stimulon of X. fastidiosa. The promoter regions of the strain 9a5c genome were screened for putative Fur boxes, and candidates were analyzed by electrophoretic mobility shift assays. Taken together, our data support the hypothesis that Fur is not solely responsible for the modulation of the iron stimulon of X. fastidiosa, and they present novel evidence for iron regulation of pathogenicity determinants.

  10. The Iron Stimulon of Xylella fastidiosa Includes Genes for Type IV Pilus and Colicin V-Like Bacteriocins▿ †

    PubMed Central

    Zaini, Paulo A.; Fogaça, Andréa C.; Lupo, Fernanda G. N.; Nakaya, Helder I.; Vêncio, Ricardo Z. N.; da Silva, Aline M.

    2008-01-01

    Xylella fastidiosa is the etiologic agent of a wide range of plant diseases, including citrus variegated chlorosis (CVC), a major threat to citrus industry. The genomes of several strains of this phytopathogen were completely sequenced, enabling large-scale functional studies. DNA microarrays representing 2,608 (91.6%) coding sequences (CDS) of X. fastidiosa CVC strain 9a5c were used to investigate transcript levels during growth with different iron availabilities. When treated with the iron chelator 2,2′-dipyridyl, 193 CDS were considered up-regulated and 216 were considered down-regulated. Upon incubation with 100 μM ferric pyrophosphate, 218 and 256 CDS were considered up- and down-regulated, respectively. Differential expression for a subset of 44 CDS was further evaluated by reverse transcription-quantitative PCR. Several CDS involved with regulatory functions, pathogenicity, and cell structure were modulated under both conditions assayed, suggesting that major changes in cell architecture and metabolism occur when X. fastidiosa cells are exposed to extreme variations in iron concentration. Interestingly, the modulated CDS include those related to colicin V-like bacteriocin synthesis and secretion and to functions of pili/fimbriae. We also investigated the contribution of the ferric uptake regulator Fur to the iron stimulon of X. fastidiosa. The promoter regions of the strain 9a5c genome were screened for putative Fur boxes, and candidates were analyzed by electrophoretic mobility shift assays. Taken together, our data support the hypothesis that Fur is not solely responsible for the modulation of the iron stimulon of X. fastidiosa, and they present novel evidence for iron regulation of pathogenicity determinants. PMID:18223091

  11. Spatiotemporal distribution of different extracellular polymeric substances and filamentation mediate Xylella fastidiosa adhesion and biofilm formation

    PubMed Central

    Janissen, Richard; Murillo, Duber M.; Niza, Barbara; Sahoo, Prasana K.; Nobrega, Marcelo M.; Cesar, Carlos L.; Temperini, Marcia L. A.; Carvalho, Hernandes F.; de Souza, Alessandra A.; Cotta, Monica A.

    2015-01-01

    Microorganism pathogenicity strongly relies on the generation of multicellular assemblies, called biofilms. Understanding their organization can unveil vulnerabilities leading to potential treatments; spatially and temporally-resolved comprehensive experimental characterization can provide new details of biofilm formation, and possibly new targets for disease control. Here, biofilm formation of economically important phytopathogen Xylella fastidiosa was analyzed at single-cell resolution using nanometer-resolution spectro-microscopy techniques, addressing the role of different types of extracellular polymeric substances (EPS) at each stage of the entire bacterial life cycle. Single cell adhesion is caused by unspecific electrostatic interactions through proteins at the cell polar region, where EPS accumulation is required for more firmly-attached, irreversibly adhered cells. Subsequently, bacteria form clusters, which are embedded in secreted loosely-bound EPS, and bridged by up to ten-fold elongated cells that form the biofilm framework. During biofilm maturation, soluble EPS forms a filamentous matrix that facilitates cell adhesion and provides mechanical support, while the biofilm keeps anchored by few cells. This floating architecture maximizes nutrient distribution while allowing detachment upon larger shear stresses; it thus complies with biological requirements of the bacteria life cycle. Using new approaches, our findings provide insights regarding different aspects of the adhesion process of X. fastidiosa and biofilm formation. PMID:25891045

  12. A suitable Xylella fastidiosa CVC strain for post-genome studies.

    PubMed

    Teixeira, Diva do Carmo; Rocha, Sanvai Regina Prado; de Santos, Mateus Almeida; Mariano, Anelise Galdino; Li, Wen Bin; Monteiro, Patricia Brant

    2004-12-01

    The genome sequence of the pathogen Xylella fastidiosa Citrus Variegated Chlorosis (CVC) strain 9a5c has revealed many genes related to pathogenicity mechanisms and virulence determinants. However, strain 9a5c is resistant to genetic transformation, impairing mutant production for the analysis of pathogenicity mechanisms and virulence determinants of this fastidious phytopathogen. By screening different strains, we found out that cloned strains J1a12, B111, and S11400, all isolated from citrus trees affected by CVC, are amenable to transformation, and J1a12 has been used as a model strain in a functional genomics program supported by FAPESP (São Paulo State Research Foundation). However, we have found that strain J1a12, unlike strains 9a5c and B111, was incapable of inducing CVC symptoms when inoculated in citrus plants. We have now determined that strain B111 is an appropriate candidate for post-genome studies of the CVC strain of X. fastidiosa.

  13. Spatiotemporal distribution of different extracellular polymeric substances and filamentation mediate Xylella fastidiosa adhesion and biofilm formation.

    PubMed

    Janissen, Richard; Murillo, Duber M; Niza, Barbara; Sahoo, Prasana K; Nobrega, Marcelo M; Cesar, Carlos L; Temperini, Marcia L A; Carvalho, Hernandes F; de Souza, Alessandra A; Cotta, Monica A

    2015-04-20

    Microorganism pathogenicity strongly relies on the generation of multicellular assemblies, called biofilms. Understanding their organization can unveil vulnerabilities leading to potential treatments; spatially and temporally-resolved comprehensive experimental characterization can provide new details of biofilm formation, and possibly new targets for disease control. Here, biofilm formation of economically important phytopathogen Xylella fastidiosa was analyzed at single-cell resolution using nanometer-resolution spectro-microscopy techniques, addressing the role of different types of extracellular polymeric substances (EPS) at each stage of the entire bacterial life cycle. Single cell adhesion is caused by unspecific electrostatic interactions through proteins at the cell polar region, where EPS accumulation is required for more firmly-attached, irreversibly adhered cells. Subsequently, bacteria form clusters, which are embedded in secreted loosely-bound EPS, and bridged by up to ten-fold elongated cells that form the biofilm framework. During biofilm maturation, soluble EPS forms a filamentous matrix that facilitates cell adhesion and provides mechanical support, while the biofilm keeps anchored by few cells. This floating architecture maximizes nutrient distribution while allowing detachment upon larger shear stresses; it thus complies with biological requirements of the bacteria life cycle. Using new approaches, our findings provide insights regarding different aspects of the adhesion process of X. fastidiosa and biofilm formation.

  14. The exopolysaccharide of Xylella fastidiosa is essential for biofilm formation, plant virulence, and vector transmission.

    PubMed

    Killiny, N; Martinez, R Hernandez; Dumenyo, C Korsi; Cooksey, D A; Almeida, R P P

    2013-09-01

    Exopolysaccharides (EPS) synthesized by plant-pathogenic bacteria are generally essential for virulence. The role of EPS produced by the vector-transmitted bacterium Xylella fastidiosa was investigated by knocking out two genes implicated in the EPS biosynthesis, gumD and gumH. Mutant strains were affected in growth characteristics in vitro, including adhesion to surfaces and biofilm formation. In addition, different assays were used to demonstrate that the mutant strains produced significantly less EPS compared with the wild type. Furthermore, gas chromatography-mass spectrometry showed that both mutant strains did not produce oligosaccharides. Biologically, the mutants were deficient in movement within plants, resulting in an avirulent phenotype. Additionally, mutant strains were affected in transmission by insects: they were very poorly transmitted by and retained within vectors. The gene expression profile indicated upregulation of genes implicated in cell-to-cell signaling and adhesins while downregulation in genes was required for within-plant movement in EPS-deficient strains. These results suggest an essential role for EPS in X. fastidiosa interactions with both plants and insects.

  15. Bioactivity of grape chemicals for human health.

    PubMed

    Iriti, Marcello; Faoro, Franco

    2009-05-01

    Grapevine (Vitis vinifera) products, grape and grape juice, represent a valuable source of bioactive phytochemicals, synthesized by three secondary metabolic pathways (phenylpropanoid, isoprenoid and alkaloid biosynthetic routes) and stored in different plant tissues. In the last decades, compelling evidence suggested that regular consumption of these products may contribute to reducing the incidence of chronic illnesses, such as cancer, cardiovascular diseases, ischemic stroke, neurodegenerative disorders and aging, in a context of the Mediterranean dietary tradition. The health benefits arising from grape product intake can be ascribed to the potpourri of biologically active chemicals occurring in grapes. Among them, the recently discovered presence of melatonin adds a new element to the already complex grape chemistry. Melatonin, and its possible synergistic action with the great variety of polyphenols, contributes to further explaining the observed health benefits associated with regular grape product consumption.

  16. Managing ochratoxin A risk in the grape-wine food chain.

    PubMed

    Visconti, Angelo; Perrone, Giancarlo; Cozzi, Giuseppe; Solfrizzo, Michele

    2008-02-01

    The main source of ochratoxin A (OTA) in the wine food chain is the infection of grapes by "black aspergilli" in the field. OTA-producing black aspergilli include principally Aspergillus carbonarius, followed by A. niger and possibly A. tubingensis. They are opportunistic fungi that develop particularly on damaged berries at ripening, although they may occur and form OTA on grapes from veraison to harvest. Climatic conditions (high humidity and temperature) and geographical location are important factors favouring OTA accumulation in grape berries. The severity of aspergillus rot is influenced by excessive irrigation and rainfall prior to harvest, which causes berry splitting. In addition, berry wounds caused by insect attack provide preferential entries for black aspergilli. High OTA levels occur in grapes severely damaged by the grape moth, Lobesia botrana, particularly in Mediterranean areas. Some grape varieties display greater susceptibility to aspergillus rot due to intrinsic genetic characteristics and bunch conformation (i.e. compact>sparse). Control measures for toxigenic mycoflora in the vineyards must consider these critical control points. Proper fungicidal and insecticidal treatments can reduce OTA contamination. Nevertheless, knowledge about the fate of OTA and its distribution in wine and winery by-products is important to manage OTA risk in contaminated stock. In our wine-making experiments, only 4% of the OTA present in grapes remained in the wine--the majority is retained in pressed grape pomaces. OTA concentration remained unchanged in wine after a 1-year aging as well as in all liquid fractions collected during vinification (i.e. must, free run wine, and wine after first and second decantation). Activated carbon can reduce OTA levels in wine but negatively affects wine quality.

  17. [The quality specification of grape seed extract].

    PubMed

    Shao, Yun-Dong; Gao, Wen-Yuan; Su, Yan-Fang; Xiao, Pei-Gen

    2005-09-01

    This paper reiviewed the current situation of quality control of grape seed extract in domestic and international market. Considering the fact that there is no national or industrial technical specifications established for the extract product, the authors suggested that two sets of quality specifications should be established for the grape seed extract. The two sets of specifications are: the high purity grape seed extract should contain polyphenol NLT 95%, monomer NLT 10%; and the grape seed extract with ordinary quality should have a procyanidolic value NLT 95, and monomer NLT 6%.

  18. trans-Resveratrol and Grape Disease Resistance. A Dynamical Study by High-Resolution Laser-Based Techniques1

    PubMed Central

    Montero, C.; Cristescu, S.M.; Jiménez, J.B.; Orea, J.M.; te Lintel Hekkert, S.; Harren, F.J.M.; González Ureña, A.

    2003-01-01

    Two modern laser-based techniques were synchronously applied to study the dynamics of the trans-resveratrol activity in Botrytis cinerea-infected grapes. Direct analysis of trans-resveratrol in both infected and noninfected grapes (Vitis vinifera, Aledo variety) was performed by using an analytical technique incorporating laser desorption coupled with laser resonant ionization and time-of-flight mass spectrometry. On the other hand, one of the most sensitive on-line methods for trace gas detection, laser photoacoustic spectroscopy, was used to investigate the involvement of the plant hormone ethylene (C2H4) in the B. cinerea grapes interaction and its temporal relationship with the trans-resveratrol content upon infection. The trans-resveratrol content and the ethylene released by noninfected grapes showed an opposite behavior. In this case, a high trans-resveratrol content corresponds to a low ethylene emission. For the B. cinerea-infected grapes, ethylene emission rises up after 48 h when the analogous content of trans-resveratrol started to decrease irreversibly. Moreover, the activity of trans-resveratrol as natural pesticide has been investigated by exogenous application on grapes. A short submerge (5 s) of the grapes in 1.6 × 10−4 m solution of trans-resveratrol delays the increase of C2H4 emission with about 48 h and produces a decrease of the C2H4 concentration and its emission rate. The treatment has positive effects on fruit conservation during storage; it doubled the normal shelf-life of grapes at room temperature, maintaining their post-harvest quality within 10 d. PMID:12529521

  19. Changes in polyphenol and polysaccharide content of grape seed extract and grape pomace after enzymatic treatment.

    PubMed

    Chamorro, S; Viveros, A; Alvarez, I; Vega, E; Brenes, A

    2012-07-15

    Grape seed extract and grape pomace are rich sources of polyphenols. The aim of this study was to evaluate the release of polyphenols, the solubilisation of carbohydrate, and the antioxidant capacity of these grape by-products after enzymatic reaction with carbohydrases (cellulolytic and pectinolytic activities) and tannase for 24h. The use of tannase in these by-products, and pectinase in grape pomace changed the galloylated form of catechin to its free form, releasing gallic acid and increasing the antioxidant activity. In grape pomace, cellulase treatment was not efficient for phenolic release and antioxidant activity improvement. The addition of carbohydrases to grape pomace, either alone or in combination, degraded the cell wall polysaccharides, increasing the content of monosaccharides. These results provide relevant data about the potential of pectinase, tannase and combinations of enzymes on the release of polyphenols and monosaccharides from grape by-products, improving the antioxidant capacity and the nutritional value. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Population Genomic Analysis of a Bacterial Plant Pathogen: Novel Insight into the Origin of Pierce's Disease of Grapevine in the U.S.

    PubMed Central

    Nunney, Leonard; Yuan, Xiaoli; Bromley, Robin; Hartung, John; Montero-Astúa, Mauricio; Moreira, Lisela; Ortiz, Beatriz; Stouthamer, Richard

    2010-01-01

    Invasive diseases present an increasing problem worldwide; however, genomic techniques are now available to investigate the timing and geographical origin of such introductions. We employed genomic techniques to demonstrate that the bacterial pathogen causing Pierce's disease of grapevine (PD) is not native to the US as previously assumed, but descended from a single genotype introduced from Central America. PD has posed a serious threat to the US wine industry ever since its first outbreak in Anaheim, California in the 1880s and continues to inhibit grape cultivation in a large area of the country. It is caused by infection of xylem vessels by the bacterium Xylella fastidiosa subsp. fastidiosa, a genetically distinct subspecies at least 15,000 years old. We present five independent kinds of evidence that strongly support our invasion hypothesis: 1) a genome-wide lack of genetic variability in X. fastidiosa subsp. fastidiosa found in the US, consistent with a recent common ancestor; 2) evidence for historical allopatry of the North American subspecies X. fastidiosa subsp. multiplex and X. fastidiosa subsp. fastidiosa; 3) evidence that X. fastidiosa subsp. fastidiosa evolved in a more tropical climate than X. fastidiosa subsp. multiplex; 4) much greater genetic variability in the proposed source population in Central America, variation within which the US genotypes are phylogenetically nested; and 5) the circumstantial evidence of importation of known hosts (coffee plants) from Central America directly into southern California just prior to the first known outbreak of the disease. The lack of genetic variation in X. fastidiosa subsp. fastidiosa in the US suggests that preventing additional introductions is important since new genetic variation may undermine PD control measures, or may lead to infection of other crop plants through the creation of novel genotypes via inter-subspecific recombination. In general, geographically mixing of previously isolated subspecies

  1. Grape anthocyanin altered by absolute sunlight exclusion

    USDA-ARS?s Scientific Manuscript database

    This research was conducted to clarify anthocyanin accumulation within ‘Merlot’ grapes in response to microclimate, specifically to light incidence, temperature, and humidity. Treatment grape clusters were light-excluded during ripening by opaque white polypropylene enclosures, during which light in...

  2. Light exclusion influence on grape anthocyanin

    USDA-ARS?s Scientific Manuscript database

    This study contrasted the anthocyanins of investigational grape clusters that developed without light incidence (light-excluded), to those of control clusters that were shaded naturally beneath the vine canopy (control-shaded). Treatment grape clusters were light-excluded during ripening by opaque w...

  3. Establishment and Production of Muscadine Grapes

    USDA-ARS?s Scientific Manuscript database

    Muscadine grapes (Vitis rotundifolia, Michx.) are adapted to the warm humid climate of the Southeastern U.S., and have been produced commercially in this region for over 300 years. Recent discoveries of the health benefits associated with muscadine grape consumption involve phenolic compounds inclu...

  4. How It All Began: Sour Grapes.

    ERIC Educational Resources Information Center

    Jennings, Maude M.

    1990-01-01

    Presents a one-act play by the author, using Eula Lee (the feminist author's alter ego) as a storyteller. Embellishes upon the sour-grapes fable to teach good sportsmanship and what "sour grapes" means. Enacts the author's ideas about teaching cultural values through storytelling. (CH)

  5. ‘Valley Pearl’ table grape

    USDA-ARS?s Scientific Manuscript database

    ‘Valley Pearl’ is an early to mid-season, white seedless table grape (Vitis vinifera L.) suitable for commercial table grape production where V. vinifera can be grown. Significant characteristics of ‘Valley Pearl’ are its high and consistent fruit production on spur pruned vines and large round berr...

  6. How It All Began: Sour Grapes.

    ERIC Educational Resources Information Center

    Jennings, Maude M.

    1990-01-01

    Presents a one-act play by the author, using Eula Lee (the feminist author's alter ego) as a storyteller. Embellishes upon the sour-grapes fable to teach good sportsmanship and what "sour grapes" means. Enacts the author's ideas about teaching cultural values through storytelling. (CH)

  7. The microbial ecology of wine grape berries.

    PubMed

    Barata, A; Malfeito-Ferreira, M; Loureiro, V

    2012-02-15

    Grapes have a complex microbial ecology including filamentous fungi, yeasts and bacteria with different physiological characteristics and effects upon wine production. Some species are only found in grapes, such as parasitic fungi and environmental bacteria, while others have the ability to survive and grow in wines, constituting the wine microbial consortium. This consortium covers yeast species, lactic acid bacteria and acetic acid bacteria. The proportion of these microorganisms depends on the grape ripening stage and on the availability of nutrients. Grape berries are susceptible to fungal parasites until véraison after which the microbiota of truly intact berries is similar to that of plant leaves, which is dominated by basidiomycetous yeasts (e.g. Cryptococcus spp., Rhodotorula spp. Sporobolomyces spp.) and the yeast-like fungus Aureobasidium pullulans. The cuticle of visually intact berries may bear microfissures and softens with ripening, increasing nutrient availability and explaining the possible dominance by the oxidative or weakly fermentative ascomycetous populations (e.g. Candida spp., Hanseniaspora spp., Metschnikowia spp., Pichia spp.) approaching harvest time. When grape skin is clearly damaged, the availability of high sugar concentrations on the berry surface favours the increase of ascomycetes with higher fermentative activity like Pichia spp. and Zygoascus hellenicus, including dangerous wine spoilage yeasts (e.g. Zygosaccharomyces spp., Torulaspora spp.), and of acetic acid bacteria (e.g. Gluconobacter spp., Acetobacter spp.). The sugar fermenting species Saccharomyces cerevisiae is rarely found on unblemished berries, being favoured by grape damage. Lactic acid bacteria are minor partners of grape microbiota and while being the typical agent of malolactic fermentation, Oenococcus oeni has been seldom isolated from grapes in the vineyard. Environmental ubiquitous bacteria of the genus Enterobacter spp., Enterococcus spp., Bacillus spp

  8. Aroma Glycosides in Grapes and Wine.

    PubMed

    Liu, Jibin; Zhu, Xiao-Lin; Ullah, Niamat; Tao, Yong-Sheng

    2017-02-01

    The major aroma components in grapes and wine include free volatile compounds and glycosidic nonvolatile compounds. The latter group of compounds is more than 10 times abundant of the former, and constitutes a big aroma reserve in grapes and wine. This review summarizes the research results obtained recently for the identification of aroma glycosides in grapes and wine, including grape glycoside structures, differences in aroma glycosides among grape varieties, hydrolysis mechanisms, and the factors that influence them. It also presents the analytical techniques used to identify the glycosidic aroma precursors. The operational strategies, challenges, and improvements of each step encountered in the analysis of glycosidic aroma precursors are described. This review intends to provide a convenient reference for researchers interested in the methods used for the determination of the aroma glucosides composition and the recognition of their chemical structures.

  9. Nanofilms of hyaluronan/chitosan assembled layer-by-layer: An antibacterial surface for Xylella fastidiosa.

    PubMed

    Hernández-Montelongo, Jacobo; Nascimento, Vicente F; Murillo, Duber; Taketa, Thiago B; Sahoo, Prasana; de Souza, Alessandra A; Beppu, Marisa M; Cotta, Monica A

    2016-01-20

    In this work, nanofilms of hyaluronan/chitosan (HA/CHI) assembled layer by layer were synthesized; their application as a potential antimicrobial material was demonstrated for the phytopathogen Xylella fastidiosa, a gram-negative bacterium, here used as a model. For the synthesis, the influence of pH and ionic strength of these natural polymer stem-solutions on final characteristics of the HA/CHI nanofilms was studied in detail. The antibacterial effect was evaluated using widefield fluorescence microscopy. These results were correlated with the chemical properties of the nanofilms, studied by FTIR and Raman spectroscopy, as well as with their morphology and surface properties characterized using SEM and AFM. The present findings can be extended to design and optimize HA/CHI nanofilms with enhanced antimicrobial behavior for other type of phytopathogenic gram-negative bacteria species, such as Xanthomonas citri, Xanthomas campestri and Ralstonia solanacearum.

  10. OTA-Grapes: A Mechanistic Model to Predict Ochratoxin A Risk in Grapes, a Step beyond the Systems Approach.

    PubMed

    Paola, Battilani; Marco, Camardo Leggieri

    2015-08-06

    Ochratoxin A (OTA) is a fungal metabolite dangerous for human and animal health due to its nephrotoxic, immunotoxic, mutagenic, teratogenic and carcinogenic effects, classified by the International Agency for Research on Cancer in group 2B, possible human carcinogen. This toxin has been stated as a wine contaminant since 1996. The aim of this study was to develop a conceptual model for the dynamic simulation of the A. carbonarius life cycle in grapes along the growing season, including OTA production in berries. Functions describing the role of weather parameters in each step of the infection cycle were developed and organized in a prototype model called OTA-grapes. Modelling the influence of temperature on OTA production, it emerged that fungal strains can be shared in two different clusters, based on the dynamic of OTA production and according to the optimal temperature. Therefore, two functions were developed, and based on statistical data analysis, it was assumed that the two types of strains contribute equally to the population. Model validation was not possible because of poor OTA contamination data, but relevant differences in OTA-I, the output index of the model, were noticed between low and high risk areas. To our knowledge, this is the first attempt to assess/model A. carbonarius in order to predict the risk of OTA contamination in grapes.

  11. OTA-Grapes: A Mechanistic Model to Predict Ochratoxin A Risk in Grapes, a Step beyond the Systems Approach

    PubMed Central

    Battilani, Paola; Camardo Leggieri, Marco

    2015-01-01

    Ochratoxin A (OTA) is a fungal metabolite dangerous for human and animal health due to its nephrotoxic, immunotoxic, mutagenic, teratogenic and carcinogenic effects, classified by the International Agency for Research on Cancer in group 2B, possible human carcinogen. This toxin has been stated as a wine contaminant since 1996. The aim of this study was to develop a conceptual model for the dynamic simulation of the A. carbonarius life cycle in grapes along the growing season, including OTA production in berries. Functions describing the role of weather parameters in each step of the infection cycle were developed and organized in a prototype model called OTA-grapes. Modelling the influence of temperature on OTA production, it emerged that fungal strains can be shared in two different clusters, based on the dynamic of OTA production and according to the optimal temperature. Therefore, two functions were developed, and based on statistical data analysis, it was assumed that the two types of strains contribute equally to the population. Model validation was not possible because of poor OTA contamination data, but relevant differences in OTA-I, the output index of the model, were noticed between low and high risk areas. To our knowledge, this is the first attempt to assess/model A. carbonarius in order to predict the risk of OTA contamination in grapes. PMID:26258791

  12. 27 CFR 4.23 - Varietal (grape type) labeling.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Varietal (grape type... Varietal (grape type) labeling. (a) General. The names of one or more grape varieties may be used as the type designation of a grape wine only if the wine is also labeled with an appellation of origin...

  13. 27 CFR 4.23 - Varietal (grape type) labeling.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Varietal (grape type... Varietal (grape type) labeling. (a) General. The names of one or more grape varieties may be used as the type designation of a grape wine only if the wine is also labeled with an appellation of origin...

  14. 27 CFR 4.23 - Varietal (grape type) labeling.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Varietal (grape type... Varietal (grape type) labeling. (a) General. The names of one or more grape varieties may be used as the type designation of a grape wine only if the wine is also labeled with an appellation of origin...

  15. 27 CFR 4.23 - Varietal (grape type) labeling.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Varietal (grape type... Varietal (grape type) labeling. (a) General. The names of one or more grape varieties may be used as the type designation of a grape wine only if the wine is also labeled with an appellation of origin...

  16. 21 CFR 73.169 - Grape color extract.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Grape color extract. 73.169 Section 73.169 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.169 Grape color extract. (a) Identity. (1) The color additive grape color extract is an aqueous solution of anthocyanin grape pigments made from...

  17. 27 CFR 4.23 - Varietal (grape type) labeling.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Varietal (grape type... Varietal (grape type) labeling. (a) General. The names of one or more grape varieties may be used as the type designation of a grape wine only if the wine is also labeled with an appellation of origin as...

  18. 21 CFR 73.169 - Grape color extract.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Grape color extract. 73.169 Section 73.169 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.169 Grape color extract. (a) Identity. (1) The color additive grape color extract is an aqueous solution of anthocyanin grape pigments made from...

  19. 21 CFR 73.169 - Grape color extract.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Grape color extract. 73.169 Section 73.169 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.169 Grape color extract. (a) Identity. (1) The color additive grape color extract is an aqueous solution of anthocyanin grape pigments made from...

  20. 21 CFR 73.169 - Grape color extract.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Grape color extract. 73.169 Section 73.169 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.169 Grape color extract. (a) Identity. (1) The color additive grape color extract is an aqueous solution of anthocyanin grape pigments made from...

  1. 21 CFR 73.169 - Grape color extract.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Grape color extract. 73.169 Section 73.169 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.169 Grape color extract. (a) Identity. (1) The color additive grape color extract is an aqueous solution of anthocyanin grape pigments made from...

  2. Calcium increases Xylella fastidiosa surface attachment, biofilm formation, and twitching motility.

    PubMed

    Cruz, Luisa F; Cobine, Paul A; De La Fuente, Leonardo

    2012-03-01

    Xylella fastidiosa is a plant-pathogenic bacterium that forms biofilms inside xylem vessels, a process thought to be influenced by the chemical composition of xylem sap. In this work, the effect of calcium on the production of X. fastidiosa biofilm and movement was analyzed under in vitro conditions. After a dose-response study with 96-well plates using eight metals, the strongest increase of biofilm formation was observed when medium was supplemented with at least 1.0 mM CaCl(2). The removal of Ca by extracellular (EGTA, 1.5 mM) and intracellular [1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA/AM), 75 μM] chelators reduced biofilm formation without compromising planktonic growth. The concentration of Ca influenced the force of adhesion to the substrate, biofilm thickness, cell-to-cell aggregation, and twitching motility, as shown by assays with microfluidic chambers and other assays. The effect of Ca on attachment was lost when cells were treated with tetracycline, suggesting that Ca has a metabolic or regulatory role in cell adhesion. A double mutant (fimA pilO) lacking type I and type IV pili did not improve biofilm formation or attachment when Ca was added to the medium, while single mutants of type I (fimA) or type IV (pilB) pili formed more biofilm under conditions of higher Ca concentrations. The concentration of Ca in the medium did not significantly influence the levels of exopolysaccharide produced. Our findings indicate that the role of Ca in biofilm formation may be related to the initial surface and cell-to-cell attachment and colonization stages of biofilm establishment, which rely on critical functions by fimbrial structures.

  3. Comparative analysis of techniques for detection of quiescent Botrytis cinerea in grapes by quantitative PCR

    USDA-ARS?s Scientific Manuscript database

    Quantitative PCR (qPCR) can be used to detect and monitor pathogen colonization, but early attempts to apply the technology to quiescent Botrytis cinerea infections of grape berries identified some specific limitations. In this study, four DNA extraction methods, two tissue-grinding methods, two gra...

  4. Inhibition of fungi from diseased grape by syringomycin E-rhamnolipid mixture

    USDA-ARS?s Scientific Manuscript database

    Fungal infections of vineyard grapes compromise the yield and organoleptic properties of wines, and there is a need for more effective fungal control measures. The aim of the present work is to evaluate the potential of a novel lipopeptide fungicidal formulation to control these diseases. A mixtur...

  5. Development of a grower performed inoculum detection assay for management of grape powdery mildew

    USDA-ARS?s Scientific Manuscript database

    Management of grape powdery mildew (Erysiphe necator) and other polycyclic diseases relies on calendar-based pesticide application schedules. However, these schedules may be adjusted to optimize and often reduce the number of applications by utilizing information generated from infection risk foreca...

  6. The emerging contribution of social wasps to grape rot disease ecology

    PubMed Central

    Boyden, Sean D.; Soriano, Jonathan-Andrew N.; Corey, Tyler B.; Leff, Jonathan W.; Fierer, Noah; Starks, Philip T.

    2017-01-01

    Grape sour (bunch) rot is a polymicrobial disease of vineyards that causes millions of dollars in lost revenue per year due to decreased quality of grapes and resultant wine. The disease is associated with damaged berries infected with a community of acetic acid bacteria, yeasts, and filamentous fungi that results in rotting berries with high amounts of undesirable volatile acidity. Many insect species cause the initial grape berry damage that can lead to this disease, but most studies have focused on the role of fruit flies in facilitating symptoms and vectoring the microorganisms of this disease complex. Like fruit flies, social wasps are abundant in vineyards where they feed on ripe berries and cause significant damage, while also dispersing yeasts involved in wine fermentation. Despite this, their possible role in disease facilitation and dispersal of grape rots has not been explored. We tested the hypothesis that the paper wasp Polistes dominulus could facilitate grape sour rot in the absence of other insect vectors. Using marker gene sequencing we characterized the bacterial and fungal community of wild-caught adults. We used a sterilized foraging arena to determine if these wasps transfer viable microorganisms when foraging. We then tested if wasps harboring their native microbial community, or those inoculated with sour rot, had an effect on grape sour rot incidence and severity using a laboratory foraging arena. We found that all wasps harbor some portion of the sour rot microbial community and that they have the ability to transfer viable microorganisms when foraging. Foraging by inoculated and uninoculated wasps led to an increase in berry rot disease symptom severity and incidence. Our results indicate that paper wasps can facilitate sour rot diseases in the absence of other vectors and that the mechanism of this facilitation may include both increasing host susceptibility and transmitting these microbial communities to the grapes. Social wasps are

  7. The emerging contribution of social wasps to grape rot disease ecology.

    PubMed

    Madden, Anne A; Boyden, Sean D; Soriano, Jonathan-Andrew N; Corey, Tyler B; Leff, Jonathan W; Fierer, Noah; Starks, Philip T

    2017-01-01

    Grape sour (bunch) rot is a polymicrobial disease of vineyards that causes millions of dollars in lost revenue per year due to decreased quality of grapes and resultant wine. The disease is associated with damaged berries infected with a community of acetic acid bacteria, yeasts, and filamentous fungi that results in rotting berries with high amounts of undesirable volatile acidity. Many insect species cause the initial grape berry damage that can lead to this disease, but most studies have focused on the role of fruit flies in facilitating symptoms and vectoring the microorganisms of this disease complex. Like fruit flies, social wasps are abundant in vineyards where they feed on ripe berries and cause significant damage, while also dispersing yeasts involved in wine fermentation. Despite this, their possible role in disease facilitation and dispersal of grape rots has not been explored. We tested the hypothesis that the paper wasp Polistes dominulus could facilitate grape sour rot in the absence of other insect vectors. Using marker gene sequencing we characterized the bacterial and fungal community of wild-caught adults. We used a sterilized foraging arena to determine if these wasps transfer viable microorganisms when foraging. We then tested if wasps harboring their native microbial community, or those inoculated with sour rot, had an effect on grape sour rot incidence and severity using a laboratory foraging arena. We found that all wasps harbor some portion of the sour rot microbial community and that they have the ability to transfer viable microorganisms when foraging. Foraging by inoculated and uninoculated wasps led to an increase in berry rot disease symptom severity and incidence. Our results indicate that paper wasps can facilitate sour rot diseases in the absence of other vectors and that the mechanism of this facilitation may include both increasing host susceptibility and transmitting these microbial communities to the grapes. Social wasps are

  8. An effective and low-cost culture medium for isolation and growth of Xylella fastidiosa from citrus and coffee plants.

    PubMed

    Lopes, S A; Torres, S C Z

    2006-12-01

    Buffered charcoal-yeast extract medium (BCYE) has been used for isolation of Xylella fastidiosa from citrus (Citrus sinensis) and coffee (Coffea arabica) plants affected by citrus variegated chlorosis (CVC) and coffee leaf scorch (CLS). BCYE is composed of ACES (2-[2-amino-2oxoethyl) amino]-ethanesulfonic acid) buffer, activated charcoal, yeast extract, L-cysteine, ferric pyrophosphate, and agar. ACES buffer is costly and not always commercially available in Brazil, and the L-cysteine and ferric pyrophosphate need to be filter sterilized in 0.22-mum pore membranes before inclusion in the medium. Omission of L-cysteine, addition of magnesium sulfate, and replacements of ACES and ferric pyrophosphate for potassium phosphate and ferrous sulfate resulted in an effective, less expensive, and entirely autoclavable medium, named phosphate buffered charcoal-yeast extract medium (PCYE). The final cost of PCYE was approximately one tenth that of BCYE. Its effectiveness was tested for the isolation of X. fastidiosa from symptomatic leaves collected from 52 citrus plants affected by CVC and 43 coffee plants affected by CLS. PCYE was as effective as BCYE and has been used routinely in our and other laboratories for isolation, growth, and quantification of X. fastidiosa from plant tissues.

  9. Expression of Xylella fastidiosa RpfF in citrus disrupts signaling in Xanthomonas citri subsp. citri and thereby its virulence.

    PubMed

    Caserta, R; Picchi, S C; Takita, M A; Tomaz, J P; Pereira, W E L; Machado, M A; Ionescu, M; Lindow, S; De Souza, A A

    2014-11-01

    Xylella fastidiosa and Xanthomonas citri subsp. citri, that cause citrus variegated chlorosis (CVC) and citrus canker diseases, respectively, utilize diffusible signal factor (DSF) for quorum sensing. DSF, produced by RpfF, are similar fatty acids in both organisms, although a different set of genes is regulated by DSF in each species. Because of this similarity, Xylella fastidiosa DSF might be recognized and affect the biology of Xanthomonas citri. Therefore, transgenic Citrus sinensis and Carrizo citrange plants overexpressing the Xylella fastidiosa rpfF were inoculated with Xanthomonas citri and changes in symptoms of citrus canker were observed. X. citri biofilms formed only at wound sites on transgenic leaves and were thicker; however, bacteria were unable to break through the tissue and form pustules elsewhere. Although abundant growth of X. citri occurred at wound sites on inoculated transgenic leaves, little growth was observed on unwounded tissue. Genes in the DFS-responsive core in X. citri were downregulated in bacteria isolated from transgenic leaves. DSF-dependent expression of engA was suppressed in cells exposed to xylem sap from transgenic plants. Thus, altered symptom development appears to be due to reduced expression of virulence genes because of the presence of antagonists of DSF signaling in X. citri in rpfF-expressing plants.

  10. Zinc Detoxification Is Required for Full Virulence and Modification of the Host Leaf Ionome by Xylella fastidiosa.

    PubMed

    Navarrete, Fernando; De La Fuente, Leonardo

    2015-04-01

    Zinc (Zn) is an essential element for all forms of life because it is a structural or catalytic cofactor of many proteins, but it can have toxic effects at high concentrations; thus, microorganisms must tightly regulate its levels. Here, we evaluated the role of Zn homeostasis proteins in the virulence of the xylem-limited bacterium Xylella fastidiosa, causal agent of Pierce's disease of grapevine, among other diseases. Two mutants of X. fastidiosa 'Temecula' affected in genes which regulate Zn homeostasis (zur) and Zn detoxification (czcD) were constructed. Both knockouts showed increased sensitivity to Zn at physiologically relevant concentrations and increased intracellular accumulation of this metal compared with the wild type. Increased Zn sensitivity was correlated with decreased growth in grapevine xylem sap, reduced twitching motility, and downregulation of exopolysaccharide biosynthetic genes. Tobacco plants inoculated with either knockout mutant showed reduced foliar symptoms and a much reduced (czcD) or absent (zur) modification of the leaf ionome (i.e., the mineral nutrient and trace element composition), as well as reduced bacterial populations. The results show that detoxification of Zn is crucial for the virulence of X. fastidiosa and verifies our previous findings that modification of the host leaf ionome correlates with bacterial virulence.

  11. Potential Anticancer Properties of Grape Antioxidants

    PubMed Central

    Zhou, Kequan; Raffoul, Julian J.

    2012-01-01

    Dietary intake of foods rich in antioxidant properties is suggested to be cancer protective. Foods rich in antioxidant properties include grape (Vitis vinifera), one of the world's largest fruit crops and most commonly consumed fruits in the world. The composition and cancer-protective effects of major phenolic antioxidants in grape skin and seed extracts are discussed in this review. Grape skin and seed extracts exert strong free radical scavenging and chelating activities and inhibit lipid oxidation in various food and cell models in vitro. The use of grape antioxidants are promising against a broad range of cancer cells by targeting epidermal growth factor receptor (EGFR) and its downstream pathways, inhibiting over-expression of COX-2 and prostaglandin E2 receptors, or modifying estrogen receptor pathways, resulting in cell cycle arrest and apoptosis. Interestingly, some of these activities were also demonstrated in animal models. However, in vivo studies have demonstrated inconsistent antioxidant efficacy. Nonetheless, a growing body of evidence from human clinical trials has demonstrated that consumption of grape, wine and grape juice exerts many health-promoting and possible anti-cancer effects. Thus, grape skin and seed extracts have great potential in cancer prevention and further investigation into this exciting field is warranted. PMID:22919383

  12. Grapes, wines, resveratrol, and heart health.

    PubMed

    Bertelli, Alberto A A; Das, Dipak K

    2009-12-01

    Epidemiological and experimental studies have revealed that a mild to moderate drinking of wine, particularly red wine, attenuates the cardiovascular, cerebrovascular, and peripheral vascular risk. However, the experimental basis for such health benefits is not fully understood. The cardioprotective effect of wine has been attributed to both components of wine: the alcoholic portion and, more importantly, the alcohol-free portion containing antioxidants. Wines are manufactured from grapes, which also contain a large variety of antioxidants, including resveratrol, catechin, epicatechin, and proanthocyanidins. Resveratrol is mainly found in the grape skin, whereas proanthocyanidins are found only in the seeds. Recent studies have demonstrated that resveratrol and proanthocyanidin are the major compounds present in grapes and wines responsible for cardioprotection. The purpose of this review is to provide evidence that grapes, wines, and resveratrol are equally important in reducing the risk of morbidity and mortality due to cardiovascular complications. Both wines and grapes can attenuate cardiac diseases such as atherosclerosis and ischemic heart disease. Recently, wine was also found to increase life span by inducing longevity genes. It appears that resveratrol and proanthocyanidins, especially resveratrol, present in grapes and wines play a crucial role in cardioprotective abilities of grapes and wines.

  13. Endophytic Methylobacterium extorquens expresses a heterologous β-1,4-endoglucanase A (EglA) in Catharanthus roseus seedlings, a model host plant for Xylella fastidiosa.

    PubMed

    Ferreira Filho, Antônio Sérgio; Quecine, Maria Carolina; Bogas, Andréa Cristina; Rossetto, Priscilla de Barros; Lima, Andre Oliveira de Souza; Lacava, Paulo Teixeira; Azevedo, João Lúcio; Araújo, Welington Luiz

    2012-04-01

    Based on the premise of symbiotic control, we genetically modified the citrus endophytic bacterium Methylobacterium extorquens, strain AR1.6/2, and evaluated its capacity to colonize a model plant and its interaction with Xylella fastidiosa, the causative agent of Citrus Variegated Chlorosis (CVC). AR1.6/2 was genetically transformed to express heterologous GFP (Green Fluorescent Protein) and an endoglucanase A (EglA), generating the strains ARGFP and AREglA, respectively. By fluorescence microscopy, it was shown that ARGFP was able to colonize xylem vessels of the Catharanthus roseus seedlings. Using scanning electron microscopy, it was observed that AREglA and X. fastidiosa may co-inhabit the C. roseus vessels. M. extorquens was observed in the xylem with the phytopathogen X. fastidiosa, and appeared to cause a decrease in biofilm formation. AREglA stimulated the production of resistance protein, catalase, in the inoculated plants. This paper reports the successful transformation of AR1.6/2 to generate two different strains with a different gene each, and also indicates that AREglA and X. fastidiosa could interact inside the host plant, suggesting a possible strategy for the symbiotic control of CVC disease. Our results provide an enhanced understanding of the M. extorquens-X. fastidiosa interaction, suggesting the application of AR1.6/2 as an agent of symbiotic control.

  14. Differential gene expression in Xylella fastidiosa 9a5c during co-cultivation with the endophytic bacterium Methylobacterium mesophilicum SR1.6/6.

    PubMed

    Dourado, Manuella Nóbrega; Santos, Daiene Souza; Nunes, Luiz Roberto; Costa de Oliveira, Regina Lúcia Batista da; de Oliveira, Marcus Vinicius; Araújo, Welington Luiz

    2015-12-01

    Xylella fastidiosa, the causal agent of citrus variegated chlorosis (CVC), colonizes plant xylem, reducing sap flow, and inducing internerval chlorosis, leaf size reduction, necrosis, and harder and smaller fruits. This bacterium may be transmitted from plant to plant by sharpshooter insects, including Bucephalogonia xanthopis. The citrus endophytic bacterium Methylobacterium mesophilicum SR1.6/6 colonizes citrus xylem and previous studies showed that this strain is also transferred from plant to plant by B. xanthopis (Insecta), suggesting that this endophytic bacterium may interact with X. fastidiosa in planta and inside the insect vector during co-transmission by the same insect vector. To better understand the X. fastidiosa behavior in the presence of M. mesophilicum, we evaluated the X. fastidiosa transcriptional profile during in vitro interaction with M. mesophilicum SR1.6/6. The results showed that during co-cultivation, X. fastidiosa down-regulated genes related to growth and up-regulated genes related to energy production, stress, transport, and motility, suggesting the existence of a specific adaptive response to the presence of M. mesophilicum in the culture medium.

  15. Ribosome display of combinatorial antibody libraries derived from mice immunized with heat-killed Xylella fastidiosa and the selection of MopB-specific single-chain antibodies.

    PubMed

    Azizi, Armaghan; Arora, Arinder; Markiv, Anatoliy; Lampe, David J; Miller, Thomas A; Kang, Angray S

    2012-04-01

    Pierce's disease is a devastating lethal disease of Vitus vinifera grapevines caused by the bacterium Xylella fastidiosa. There is no cure for Pierce's disease, and control is achieved predominantly by suppressing transmission of the glassy-winged sharpshooter insect vector. We present a simple robust approach for the generation of panels of recombinant single-chain antibodies against the surface-exposed elements of X. fastidiosa that may have potential use in diagnosis and/or disease transmission blocking studies. In vitro combinatorial antibody ribosome display libraries were assembled from immunoglobulin transcripts rescued from the spleens of mice immunized with heat-killed X. fastidiosa. The libraries were used in a single round of selection against an outer membrane protein, MopB, resulting in the isolation of a panel of recombinant antibodies. The potential use of selected anti-MopB antibodies was demonstrated by the successful application of the 4XfMopB3 antibody in an enzyme-linked immunosorbent assay (ELISA), a Western blot assay, and an immunofluorescence assay (IFA). These immortalized in vitro recombinant single-chain antibody libraries generated against heat-killed X. fastidiosa are a resource for the Pierce's disease research community that may be readily accessed for the isolation of antibodies against a plethora of X. fastidiosa surface-exposed antigenic molecules.

  16. Characterization of the Xylella fastidiosa PD1671 gene encoding degenerate c-di-GMP GGDEF/EAL domains, and its role in the development of Pierce's disease.

    PubMed

    Cursino, Luciana; Athinuwat, Dusit; Patel, Kelly R; Galvani, Cheryl D; Zaini, Paulo A; Li, Yaxin; De La Fuente, Leonardo; Hoch, Harvey C; Burr, Thomas J; Mowery, Patricia

    2015-01-01

    Xylella fastidiosa is an important phytopathogenic bacterium that causes many serious plant diseases including Pierce's disease of grapevines. X. fastidiosa is thought to induce disease by colonizing and clogging xylem vessels through the formation of cell aggregates and bacterial biofilms. Here we examine the role in X. fastidiosa virulence of an uncharacterized gene, PD1671, annotated as a two-component response regulator with potential GGDEF and EAL domains. GGDEF domains are found in c-di-GMP diguanylate cyclases while EAL domains are found in phosphodiesterases, and these domains are for c-di-GMP production and turnover, respectively. Functional analysis of the PD1671 gene revealed that it affected multiple X. fastidiosa virulence-related phenotypes. A Tn5 PD1671 mutant had a hypervirulent phenotype in grapevines presumably due to enhanced expression of gum genes leading to increased exopolysaccharide levels that resulted in elevated biofilm formation. Interestingly, the PD1671 mutant also had decreased motility in vitro but did not show a reduced distribution in grapevines following inoculation. Given these responses, the putative PD1671 protein may be a negative regulator of X. fastidiosa virulence.

  17. Functional and structural studies of the disulfide isomerase DsbC from the plant pathogen Xylella fastidiosa reveals a redox-dependent oligomeric modulation in vitro.

    PubMed

    Santos, Clelton A; Toledo, Marcelo A S; Trivella, Daniela B B; Beloti, Lilian L; Schneider, Dilaine R S; Saraiva, Antonio M; Crucello, Aline; Azzoni, Adriano R; Souza, Alessandra A; Aparicio, Ricardo; Souza, Anete P

    2012-10-01

    Xylella fastidiosa is a Gram-negative bacterium that grows as a biofilm inside the xylem vessels of susceptible plants and causes several economically relevant crop diseases. In the present study, we report the functional and low-resolution structural characterization of the X. fastidiosa disulfide isomerase DsbC (XfDsbC). DsbC is part of the disulfide bond reduction/isomerization pathway in the bacterial periplasm and plays an important role in oxidative protein folding. In the present study, we demonstrate the presence of XfDsbC during different stages of X. fastidiosa biofilm development. XfDsbC was not detected during X. fastidiosa planktonic growth; however, after administering a sublethal copper shock, we observed an overexpression of XfDsbC that also occurred during planktonic growth. These results suggest that X. fastidiosa can use XfDsbC in vivo under oxidative stress conditions similar to those induced by copper. In addition, using dynamic light scattering and small-angle X-ray scattering, we observed that the oligomeric state of XfDsbC in vitro may be dependent on the redox environment. Under reducing conditions, XfDsbC is present as a dimer, whereas a putative tetrameric form was observed under nonreducing conditions. Taken together, our findings demonstrate the overexpression of XfDsbC during biofilm formation and provide the first structural model of a bacterial disulfide isomerase in solution.

  18. Influence of carvacrol on survival of Botrytis cinerea inoculated in table grapes.

    PubMed

    Martínez-Romero, Domingo; Guillén, Fabián; Valverde, Juan Miguel; Bailén, Gloria; Zapata, Pedro; Serrano, María; Castillo, Salvador; Valero, Daniel

    2007-04-10

    In this paper, the role of carvacrol vapour atmosphere on Botrytis cinerea inoculated in PDA or in grape berries was studied. Four concentrations inside packages were assayed (0.05, 0.2, 0.5 and 1.0 ml l(-1)). All concentrations inhibited totally the growth of B. cinerea in PDA, while in berries the reduction of decayed fruits was significantly greater as carvacrol concentration increased. In addition, the fungal growth (area and volume of infection) was also reduced and dependent on carvacrol concentration. Ethylene and respiration rate (berry physiological parameters) increased drastically in control inoculated-grapes, while these increases were lower as higher were the carvacrol applied doses. The data presented in this work suggest that carvacrol could be used as an innovative tool to control fungal decay during table grape storage, as alternative to the use of synthetic fungicides such as SO2.

  19. Rapidly changing climatic conditions for wine grape growing in the Okanagan Valley region of British Columbia, Canada.

    PubMed

    Rayne, Sierra; Forest, Kaya

    2016-06-15

    A statistical analysis was conducted on long-term climate records for sites bordering Okanagan Lake in the Okanagan Valley viticultural region of British Columbia, Canada. Average wine grape growing season temperatures are increasing rapidly in the area over the post-1980 period at rates upwards of 7.0±1.3°C/century. Similar increases in the average dormant season temperature are evident. These temperature changes are likely some of the most extreme observed among the world's wine producing areas during the past few decades. Growing degree day base 10°C (GDD10) has increased by nearly 50% at some locations since the 1970s, resulting in major impacts on the corresponding climate classification for viticulture. If current climate trends continue, the southern and central portions of the region will likely enter Winkler region II within the next few decades, placing them in the same category as well-established warmer wine regions from France, Spain, Italy, and Australia. The large dormant season temperature increases over the last several decades have resulted in the area no longer being a cold season outlier when compared to most other cool-climate viticultural areas. Based on average growing season temperatures, the southern end of Okanagan Lake has moved out of the cool-climate viticultural classification and into the intermediate zone, while the central and northern regions are now at the cool/intermediate viticulture interface, similar to the historical positions of the Rhine Valley in Germany, northern Oregon in the United States, and the Loire Valley, Burgundy-Cote, Burgundy-Beaujolais, and Champagne appelations of France. The corresponding suitable grape species for the area have evolved into warmer region varietals during this time frame, having substantial economic impacts on producers. Increased temperatures are also expected to bring greater threats from agricultural pests, notably Pierce's disease from the bacterium Xylella fastidiosa.

  20. Simultaneous allergy to vine pollen and grape.

    PubMed

    Mur, P; Feo Brito, F; Bartolomé, B; Galindo, P A; Gómez, E; Borja, J; Alonso, A

    2006-01-01

    We report the case of an 18-year-old female student suffering from seasonal rhinoconjunctivitis with sensitization to pollens from vine and also from grass, olive, and Chenopodiaceae plants who had recently developed episodes of itching, maculopapular rash, and facial angioedema after eating grapes. Testing revealed positive reactions to vine pollen and grapes, and specific IgE were found for both allergens. Immunoblotting and inhibition assays revealed cross-reactivity between the allergenic structures of vine pollen and grape fruit and also among botanically unrelated pollens.

  1. The Antitoxin Protein of a Toxin-Antitoxin System from Xylella fastidiosa Is Secreted via Outer Membrane Vesicles

    PubMed Central

    Santiago, André da Silva; Mendes, Juliano S.; dos Santos, Clelton A.; de Toledo, Marcelo A. S.; Beloti, Lilian L.; Crucello, Aline; Horta, Maria A. C.; Favaro, Marianna T. de Pinho; Munar, Duber M. M.; de Souza, Alessandra A.; Cotta, Mônica A.; de Souza, Anete P.

    2016-01-01

    The Xylella fastidiosa subsp pauca strain 9a5c is a Gram-negative, xylem-limited bacterium that is able to form a biofilm and affects citrus crops in Brazil. Some genes are considered to be involved in biofilm formation, but the specific mechanisms involved in this process remain unknown. This limited understanding of how some bacteria form biofilms is a major barrier to our comprehension of the progression of diseases caused by biofilm-producing bacteria. Several investigations have shown that the toxin-antitoxin (TA) operon is related to biofilm formation. This operon is composed of a toxin with RNAse activity and its cognate antitoxin. Previous reports have indicated that the antitoxin is able to inhibit toxin activity and modulate the expression of the operon as well as other target genes involved in oxidative stress and mobility. In this study, we characterize a toxin-antitoxin system consisting of XfMqsR and XfYgiT, respectively, from X. fastidiosa subsp. pauca strain 9a5c. These proteins display a high similarity to their homologs in X. fastidiosa strain Temecula and a predicted tridimensional structure that is similar to MqsR-YgiT from Escherichia coli. The characterization was performed using in vitro assays such as analytical ultracentrifugation (AUC), size exclusion chromatography, isothermal titration calorimetry, and Western blotting. Using a fluorometric assay to detect RNAses, we demonstrated that XfMqsR is thermostable and can degrade RNA. XfMqsR is inhibited by XfYgiT, which interacts with its own promoter. XfYgiT is known to be localized in the intracellular compartment; however, we provide strong evidence that X. fastidiosa secretes wild-type XfYgiT into the extracellular environment via outer membrane vesicles, as confirmed by Western blotting and specific immunofluorescence labeling visualized by fluorescence microscopy. Taken together, our results characterize the TA system from X. fastidiosa strain 9a5c, and we also discuss the possible

  2. Anticancer activity of grape and grape skin extracts alone and combined with green tea infusions.

    PubMed

    Morré, Dorothy M; Morré, D James

    2006-07-18

    Grapes and grape extracts were compared for inhibition of a growth-related and cancer-specific form of cell surface NADH oxidase with protein disulfide-thiol interchange activity designated tNOX from human cervical carcinoma (HeLa) cells and growth of HeLa and mouse mammary 4T1 cells in culture and transplanted tumors in mice. Grapes and grape extracts of several varieties had activity. With an extracted grape preparation provided by the California Table Grape Commission, an active fraction was eluted with methanol from a Diaion HP-20 column after removal of inactive water-soluble materials. Grape skins were a much more potent source than either grape pulp, juice or seeds. Ethanol extracts of the ground freeze-dried pomace was an excellent source. The grape extracts interacted, often synergistically, with decaffeinated green tea extracts both in the inhibition of tNOX activity and in the inhibition of cancer cell growth. Intratumoral injections of a 25:1 mixture of a green tea extract plus ground freeze-dried pomace was nearly as effective as standard synergistic green tea-Capsicum mixtures in inhibiting growth of 4T1 mammary tumors in situ in mice.

  3. Toxicity of sulcotrione and grape marc on Vicia faba cells.

    PubMed

    Sta, Chaima; Goujon, Eric; Ferjani, Ezzeddine; Ledoigt, Gérard

    2014-12-10

    The cell toxicity of sulcotrione, a selective triketone herbicide, was evaluated on Vicia faba. Sulcotrione, trademark Mikado, grape marc, and mixtures of sulcotrione or Mikado with grape marc induced cell death. Addition of grape marc to either sulcotrione or Mikado enhanced cell death, especially with Mikado. Addition of grape marc to herbicides, sulcotrione, or Mikado resulted in different expression of genes usually associated with cell stress. Mixtures of grape marc and herbicides enhanced transcript accumulation for ubiquitin, hsp 70, and cytosolic superoxide dismutase, but did not change ascorbate peroxidase transcript accumulation. The results thus provide evidence that sulcotrione, Mikado, and mixtures with grape marc can trigger cell death and specific gene expressions. Cocktails of products with sulcotrione, such as commercial additives and grape marc, can modify biological features of pesticide. Moreover, grape marc differently enhanced cell toxicity of sulcotrione and Mikado, suggesting a synergy between pesticide products and grape marc.

  4. Non contiguous-finished genome sequence and description of Dielma fastidiosa gen. nov., sp. nov., a new member of the Family Erysipelotrichaceae

    PubMed Central

    Ramasamy, Dhamodharan; Lagier, Jean-Christophe; Nguyen, Thi Tien; Raoult, Didier; Fournier, Pierre-Edouard

    2013-01-01

    Dielma fastidiosa strain JC13T gen. nov., sp. nov. is the type strain of D. fastidiosa gen. nov., sp. nov., the type species of a new genus within the family Erysipelotrichaceae. This strain, whose draft genome is described here, was isolated from the fecal flora of a healthy 16-year-old male Senegalese volunteer. D. fastidiosa is a Gram-negative anaerobic rod. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,574,031 bp long genome comprises a 3,556,241-bp chromosome and a 17,790-bp plasmid. The chromosome contains 3,441 protein-coding and 50 RNA genes, including 3 rRNA genes, whereas the plasmid contains 17 protein-coding genes. PMID:23991263

  5. Overview of Chinese GRAPES Data Assimilation System

    NASA Astrophysics Data System (ADS)

    Liu, Yan

    2017-04-01

    The development of data assimilation system of Global and Regional Assimilation and Prediction System (GRAPES in short) which is Chinese new generation operational numerical weather prediction system completed in recent years is reviewed in this paper, including the design scheme and main characteristics. GRAPES adopts the variational approach with stresses at application of various remote sensing observational data. Its development path is from three dimensional to four dimensional assimilation. It may be implemented with limited area or global configurations. The three dimensional variational data assimilation systems have been operational in the national and a few of regional meteorological centers. The global four dimensional assimilation system is in pre-operational experiments, and will be upgraded. After a brief introduction to the GRAPES data assimilation system, results of a series of validations of GRAPES analyses against the observation data and analyses derived from other operational NWP center to assess its performance are presented.

  6. Acetic acid bacteria isolated from grapes of South Australian vineyards.

    PubMed

    Mateo, E; Torija, M J; Mas, A; Bartowsky, E J

    2014-05-16

    Acetic acid bacteria (AAB) diversity from healthy, mould-infected and rot-affected grapes collected from three vineyards of Adelaide Hills (South Australia) was analyzed by molecular typing and identification methods. Nine different AAB species were identified from the 624 isolates recovered: Four species from Gluconobacter genus, two from Asaia and one from Acetobacter were identified by the analysis of 16S rRNA gene and 16S-23S rRNA gene internal transcribed spacer. However, the identification of other isolates that were assigned as Asaia sp. and Ameyamaea chiangmaiensis required more analysis for a correct species classification. The species of Gluconobacter cerinus was the main one identified; while one genotype of Asaia siamensis presented the highest number of isolates. The number of colonies recovered and genotypes identified was strongly affected by the infection status of the grapes; the rot-affected with the highest number. However, the species diversity was similar in all the cases. High AAB diversity was detected with a specific genotype distribution for each vineyard. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Grape

    MedlinePlus

    ... pressure. However, in men with metabolic syndrome, a cluster of conditions that increase the risk for heart ... the risk factors associated with metabolic syndrome, a cluster of conditions that increase the risk for heart ...

  8. Smoothed particle hydrodynamics with GRAPE-1A

    NASA Technical Reports Server (NTRS)

    Umemura, Masayuki; Fukushige, Toshiyuki; Makino, Junichiro; Ebisuzaki, Toshikazu; Sugimoto, Daiichiro; Turner, Edwin L.; Loeb, Abraham

    1993-01-01

    We describe the implementation of a smoothed particle hydrodynamics (SPH) scheme using GRAPE-1A, a special-purpose processor used for gravitational N-body simulations. The GRAPE-1A calculates the gravitational force exerted on a particle from all other particles in a system, while simultaneously making a list of the nearest neighbors of the particle. It is found that GRAPE-1A accelerates SPH calculations by direct summation by about two orders of magnitudes for a ten thousand-particle simulation. The effective speed is 80 Mflops, which is about 30 percent of the peak speed of GRAPE-1A. Also, in order to investigate the accuracy of GRAPE-SPH, some test simulations were executed. We found that the force and position errors are smaller than those due to representing a fluid by a finite number of particles. The total energy and momentum were conserved within 0.2-0.4 percent and 2-5 x 10 exp -5, respectively, in simulations with several thousand particles. We conclude that GRAPE-SPH is quite effective and sufficiently accurate for self-gravitating hydrodynamics.

  9. Characterization of a putative Xylella fastidiosa diffusible signal factor by HRGC-EI-MS.

    PubMed

    Colnaghi Simionato, Ana Valéria; da Silva, Denise Santos; Lambais, Marcio Rodrigues; Carrilho, Emanuel

    2007-10-01

    Xylella fastidiosa (X.f.) is a plant pathogen with high levels of genomic similarity to Xanthomonas campestris pv. campestris (X.c.c.). It has been shown that X. fastidiosa synthesizes a putative diffusible signal factor (X.f.-DSF) that activates regulation of pathogenicity factor (rpf) genes in a X.c.c. reporter system, which might be involved in the regulation of pathogenesis associated genes as in X.c.c., as well as in quorum-sensing. The nature of the X.f.-DSF is not known, whereas the X.c.c.-DSF has been identified as cis-11-methyl-2-dodecenoic acid. In this work, the chemical nature of a putative X.f.-DSF molecule, able to restore endoglucanase activity in a X.c.c. rpfF mutant, was investigated as if it was a fatty acid derivative. Bioassays with X.c.c. reporter bacterium and X.f. culture extracts, based on endoglucanase restoration activity, were also carried out in order to confirm the DSFs molecules similarities. For this reason, a gas chromatography-mass spectrometry method was developed with standard fatty acids methyl esters mixtures. The retention time, as well as the fragmentation patterns, of each standard was used to identify the DSF molecule synthesized by X.f. in the culture medium. Typical ester fragmentation patterns (the derivatized analyte) were observed, such as: McLafferty rearrangement and migration of the Hdelta followed by 1,4-hydrogen shift and cleavage of the bond Cbeta--Cgamma, confirming the nature of this molecule. This confirmation was corroborated by the common peaks in both spectra. Besides, the observed retention time reinforces our conclusion since it corresponds to a methyl ester with 15 carbons. Since the X.f.-DSF molecule was tentatively identified as 12-methyl-tetradecanoic acid (by mass spectra library comparison), this standard compound was also analyzed, strongly suggesting that this is the identification of such a molecule. To our knowledge, this is the first time a DSF produced by X.f. has been characterized.

  10. Characterization of a putative Xylella fastidiosa diffusible signal factor by HRGC-EI-MS.

    PubMed

    Colnaghi Simionato, Ana Valéria; da Silva, Denise Santos; Lambais, Marcio Rodrigues; Carrilho, Emanuel

    2007-04-01

    Xylella fastidiosa (X.f.) is a plant pathogen with high levels of genomic similarity to Xanthomonas campestris pv. campestris (X.c.c.). It has been shown that X. fastidiosa synthesizes a putative diffusible signal factor (X.f.-DSF) that activates regulation of pathogenicity factor (rpf) genes in a X.c.c. reporter system, which might be involved in the regulation of pathogenesis associated genes as in X.c.c., as well as in quorum-sensing. The nature of the X.f.-DSF is not known, whereas the X.c.c.-DSF has been identified as cis-11-methyl-2-dodecenoic acid. In this work, the chemical nature of a putative X.f.-DSF molecule, able to restore endoglucanase activity in a X.c.c. rpfF mutant, was investigated as if it was a fatty acid derivative. Bioassays with X.c.c. reporter bacterium and X.f. culture extracts, based on endoglucanase restoration activity, were also carried out in order to confirm the DSFs molecules similarities. For this reason, a gas chromatography-mass spectrometry method was developed with standard fatty acids methyl esters mixtures. The retention time, as well as the fragmentation patterns, of each standard was used to identify the DSF molecule synthesized by X.f. in the culture medium. Typical ester fragmentation patterns (the derivatized analyte) were observed, such as: McLafferty rearrangement and migration of the Hdelta followed by 1,4-hydrogen shift and cleavage of the bond Cbeta-Cgamma, confirming the nature of this molecule. This confirmation was corroborated by the common peaks in both spectra. Besides, the observed retention time reinforces our conclusion since it corresponds to a methyl ester with 15 carbons. Since the X.f.-DSF molecule was tentatively identified as 12-methyl-tetradecanoic acid (by mass spectra library comparison), this standard compound was also analyzed, strongly suggesting that this is the identification of such a molecule. To our knowledge, this is the first time a DSF produced by X.f. has been characterized. Copyright

  11. Acoustic detection of arthropod infestation of grape roots: scouting for grape root borer (Lepidoptera:Sesiidae)

    USDA-ARS?s Scientific Manuscript database

    Grape root borer, Vitacea polistiformis (Harris), is the key pest of grapes in Florida. Chlorpyrifos is the only chemical registered in Florida for control, but it is not an ideal control tool because it is highly toxic to birds, fish, aquatic invertebrates, and honeybees, and its recommended timing...

  12. Identification and field evaluation of grape shoot volatiles attractive to female grape berry moth (Paralobesia viteana)

    USDA-ARS?s Scientific Manuscript database

    Solid-phase microextraction (SPME) and gas chromatography coupled with electroantennographic detection (GC-EAD) were used to identify volatile compounds from shoots of riverbank grape (Vitis riparia) acting as behavioral attractants for female grape berry moth (GBM, Paralobesia viteana). Consistent...

  13. Impact of winery wastewater irrigation on soil, grape nutrition, and grape and wine quality

    USDA-ARS?s Scientific Manuscript database

    Winery wastewater (WW) reuse has the potential to provide more sustainable vineyard irrigation. This study investigated the effects of WW irrigation on grape and wine chemical composition and sensory attributes in vineyards in Napa and Sonoma Counties. The life cycle of the grape/wine production was...

  14. Preparation of resveratrol-enriched grape juice from ultrasonication treated grape fruits.

    PubMed

    Hasan, Md Mohidul; Yun, Hae-Keun; Kwak, Eun-Jung; Baek, Kwang-Hyun

    2014-03-01

    Grape (Vitis spp.) is a major source of resveratrol that can be eaten directly or after making jam, jelly, wine and juice. Resveratrol (3,5,4'-trihydroxystilbene) has a profound positive influence on human health, including anti-carcinogenic, anti-cancer, anti-inflammatory, and anti-ageing effects and the ability to lower blood sugar. During industrial production of grape juice, resveratrol is lost because of the use of clarifying agents and filtration; therefore, commercial grape juice contains very low amounts of resveratrol. In this study, we investigated the accumulation of resveratrol in grape juice prepared from three varieties of grape, viz. Campbell Early, Muscat Bailey A (MBA) and Kyoho, following post-harvest ultrasonication cleaning for 5 min and 6h of incubation in the dark at 25 °C. This process resulted in the amounts of resveratrol increasing by 1.53, 1.15 and 1.24 times in juice prepared from Campbell Early, MBA and Kyoho, respectively, without changing the amounts of total soluble solids. Overall, our results indicate that ultrasonication treatment of post-harvested grape fruits can be an effective method for producing resveratrol-enriched grape juice as well as cleaning grapes thoroughly. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Fungi and mycotoxins in vineyards and grape products.

    PubMed

    Hocking, Ailsa D; Leong, Su-Lin L; Kazi, Benozir A; Emmett, Robert W; Scott, Eileen S

    2007-10-20

    Many fungi may occur on grapes during growth in the vineyard, but the main concern from the viewpoint of mycotoxin contamination is the black Aspergilli, Aspergillus carbonarius and A. niger. These fungi are capable of producing ochratoxin A (OA) which may contaminate grapes and grape products such as wine, grape juice and dried vine fruit. Understanding the ecology and physiology of the black Aspergilli can provide tools for management of OA at all stages of grape production and processing. In the vineyard, careful management of cultivation, irrigation and pruning can assist in minimising the levels of black Aspergilli in the soil, which in turn, can minimise contamination of grapes by these fungi. Minimising damage to grapes on the vine by the use of open vine canopies, grape varieties with resistance to rain damage and by the management of insect pests and fungal diseases (e.g., mildew, Botrytis bunch rot) can reduce the incidence of Aspergillus rot in mature berries. The risk of OA in table grapes can be minimised by careful visual inspection to avoid damaged and discoloured berries. In wine, harvesting grapes with minimal damage, rapid processing and good sanitation practices in the winery assist in minimising OA. During vinification, pressing of grapes, and clarification steps which remove grape solids, grape proteins and spent yeast can also remove a significant proportion of OA. For dried vine fruit production, avoiding berry damage, rapid drying, and final cleaning and sorting to remove dark berries can reduce overall OA levels in finished products.

  16. Infections

    MedlinePlus

    ... Eye Infections Pinkeye (Conjunctivitis) Styes Fungal Infections (Ringworm, Yeast, etc.) Diaper Rash Infections That Pets Carry Oral ... Pneumonia Tinea (Ringworm, Jock Itch, Athlete's Foot) Vaginal Yeast Infections Immunizations Do My Kids Need Vaccines Before ...

  17. Behavioral response of grape root borer (Lepidoptera: Sesiidae) neonates to grape root volatiles.

    PubMed

    Rijal, J P; Zhang, A; Bergh, J C

    2013-12-01

    Grape root borer, Vitacea polistiformis (Harris), is an oligophagous and potentially destructive pest of grape in commercial vineyards throughout much of the eastern United States. Larvae feed on vine roots, although little is known about their below-ground interactions with host plants. The behavioral response of groups of grape root borer neonates to stimuli from host and nonhost roots was evaluated in single and paired stimuli bioassays in which stimuli were presented in opposing wells attached to the bottom of petri dish arenas. Stimulus sources included root pieces and root headspace volatiles from 3309 and 420-A grape rootstocks (host) and apple (nonhost) and ethanol-based extracts of 3309 and 420-A roots. In single stimulus assays, significantly more larvae were recovered from wells containing grape roots, apple roots, grape extracts, and grape root volatiles than from control wells, but there was no significant response to volatiles collected from the headspace of apple roots. In paired stimuli assays, significantly more larvae were recovered from wells containing grape than apple roots. There was no difference in larval distribution between wells when 420-A and 3309 roots were presented simultaneously, although a significantly greater response to 3309 than 420-A root extract was recorded. When soil was added to the assays, significantly more larvae were recovered from wells containing grape roots than from those containing only soil, but this response was not detected in assays using buried apple roots. These results are discussed in relation to the plant-insect interactions between grape root borer larvae and their Vitaceae hosts.

  18. Nutritional study of copper and zinc in grapes and commercial grape juices from Spain.

    PubMed

    Olalla, Manuel; Fernández, Javier; Cabrera, Carmen; Navarro, Miguel; Giménez, Rafael; López, M Carmen

    2004-05-05

    This paper presents the levels of copper and zinc determined in a total of 66 samples of the most widely consumed varieties of white and red grapes in Spain, as well as those of 60 samples of grape juice (39 from white varieties and 21 from red ones) chosen from the main commercial brands in the country. Atomic absorption spectroscopy was used as analytical technique, with electrothermal atomization after digestion of the sample with HNO(3)-H(2)O(2) for grapes and with HNO(3) for grape juice. The mean Zn contents obtained (0.0462 mg/100 g in grapes and 0.0460 mg/100 mL in grape juice) are lower than those provided by most of the more commonly used food composition tables. The mean Cu contents were 0.0515 mg/100 g in grapes and 0.0063 mg/100 mL in grape juice. On the basis of these data and the official data on consumption of grapes and grape juice in Spain, the contribution of both products to the recommended daily intake of zinc (15 and 12 mg/day for healthy adult men and women, respectively) is estimated to be approximately 0.1%, whereas for Cu, this supply represents rather more than 0.25% of the established ESADDI (1.5-3 mg/day in adults). The growing popularity of these products in recent years, on the basis of its nutritional properties and beneficial effects, requires additional data, and the present findings are of potential use to food composition tables.

  19. Whole-genome comparative analysis of three phytopathogenic Xylella fastidiosa strains

    PubMed Central

    Bhattacharyya, Anamitra; Stilwagen, Stephanie; Ivanova, Natalia; D'Souza, Mark; Bernal, Axel; Lykidis, Athanasios; Kapatral, Vinayak; Anderson, Iain; Larsen, Niels; Los, Tamara; Reznik, Gary; Selkov, Eugene; Walunas, Theresa L.; Feil, Helene; Feil, William S.; Purcell, Alexander; Lassez, Jean-Louis; Hawkins, Trevor L.; Haselkorn, Robert; Overbeek, Ross; Predki, Paul F.; Kyrpides, Nikos C.

    2002-01-01

    Xylella fastidiosa (Xf) causes wilt disease in plants and is responsible for major economic and crop losses globally. Owing to the public importance of this phytopathogen we embarked on a comparative analysis of the complete genome of Xf pv citrus and the partial genomes of two recently sequenced strains of this species: Xf pv almond and Xf pv oleander, which cause leaf scorch in almond and oleander plants, respectively. We report a reanalysis of the previously sequenced Xf 9a5c (CVC, citrus) strain and the two “gapped” Xf genomes revealing ORFs encoding critical functions in pathogenicity and conjugative transfer. Second, a detailed whole-genome functional comparison was based on the three sequenced Xf strains, identifying the unique genes present in each strain, in addition to those shared between strains. Third, an “in silico” cellular reconstruction of these organisms was made, based on a comparison of their core functional subsystems that led to a characterization of their conjugative transfer machinery, identification of potential differences in their adhesion mechanisms, and highlighting of the absence of a classical quorum-sensing mechanism. This study demonstrates the effectiveness of comparative analysis strategies in the interpretation of genomes that are closely related. PMID:12205291

  20. Structural characterization of the H-NS protein from Xylella fastidiosa and its interaction with DNA.

    PubMed

    Rosselli-Murai, Luciana K; Sforça, Maurício L; Sassonia, Rogério C; Azzoni, Adriano R; Murai, Marcelo J; de Souza, Anete P; Zeri, Ana C

    2012-10-01

    The nucleoid-associated protein H-NS is a major component of the bacterial nucleoid involved in DNA compaction and transcription regulation. The NMR solution structure of the Xylella fastidiosa H-NS C-terminal domain (residues 56-134) is presented here and consists of two beta-strands and two alpha helices, with one loop connecting the two beta-strands and a second loop connecting the second beta strand and the first helix. The amide (1)H and (15)N chemical shift signals for a sample of XfH-NS(56-134) were monitored in the course of a titration series with a 14-bp DNA duplex. Most of the residues involved in contacts to DNA are located around the first and second loops and in the first helix at a positively charged side of the protein surface. The overall structure of the Xylella H-NS C-terminal domain differ significantly from Escherichia coli and Salmonella enterica H-NS proteins, even though the DNA binding motif in loop 2 adopt similar conformation, as well as β-strand 2 and loop 1. Interestingly, we have also found that the DNA binding site is expanded to include helix 1, which is not seen in the other structures.

  1. Characterization of the LysR-type transcriptional regulator YcjZ-like from Xylella fastidiosa overexpressed in Escherichia coli.

    PubMed

    Santiago, André S; Santos, Clelton A; Mendes, Juliano S; Toledo, Marcelo A S; Beloti, Lilian L; Souza, Alessandra A; Souza, Anete P

    2015-09-01

    The Xylella fastidiosa 9a5c strain is a xylem-limited phytopathogen that is the causal agent of citrus variegated chlorosis (CVC). This bacterium is able to form a biofilm and occlude the xylem vessels of susceptible plants, which leads to significant agricultural and economic losses. Biofilms are associated with bacterial pathogenicity because they are very resistant to antibiotics and other metal-based chemicals that are used in agriculture. The X. fastidiosa YcjZ-like (XfYcjZ-like) protein belongs to the LysR-type transcriptional regulator (LTTR) family and is involved in various cellular functions that range from quorum sensing to bacterial survival. In the present study, we report the cloning, expression and purification of XfYcjZ-like, which was overexpressed in Escherichia coli. The secondary folding of the recombinant and purified protein was assessed by circular dichroism, which revealed that XfYcjZ-like contains a typical α/β fold. An initial hydrodynamic characterization showed that XfYcjZ-like is a globular tetramer in solution. In addition, using a polyclonal antibody against XfYcjZ-like, we assessed the expression profile of this protein during the different developmental phases of X. fastidiosa in in vitro cultivated biofilm cells and demonstrated that XfYcjZ-like is upregulated in planktonic cells in response to a copper shock treatment. Finally, the ability of XfYcjZ-like to interact with its own predicted promoter was confirmed in vitro, which is a typical feature of LysR. Taken together, our findings indicated that the XfYcjZ-like protein is involved in both the organization of the architecture and the maturation of the bacterial biofilm and that it is responsive to oxidative stress.

  2. Current status of the GRAPE balloon program

    NASA Astrophysics Data System (ADS)

    McConnell, Mark L.; Bloser, Peter F.; Ertley, Camden; Legere, Jason; Ryan, James M.; Wasti, Sambid K.

    2014-07-01

    The Gamma RAy Polarimeter Experiment (GRAPE) was first own on a 26-hour balloon flight in the fall of 2011. GRAPE consists of an array of Compton polarimeter modules (based on traditional scintillation technologies) designed to operate in the energy range from 50 keV up to 500 keV. The ultimate goal of our program is to operate GRAPE in a wide FoV configuration for the study of gamma-ray bursts. For the first balloon flight, GRAPE was configured in a collimated mode to facilitate observations of known point sources. The Crab nebula/pulsar, the active Sun, and Cygnus X{1 were the primary targets for the first flight. Polarization results from this flight are summarized. Plans for the next GRAPE balloon flight, which is scheduled to take place in the fall of 2014 from Ft. Sumner, NM, will also be presented. These plans involve modifications designed to improve the polarization sensitivity, including an expansion of the array of polarimeter modules from 16 to 24 and improvements to the instrument shielding. These improvements to the instrument will significantly improve the polarization sensitivity, enabling a measurement of the Crab Nebula polarization to be made during the 2014 balloon flight.

  3. 21 CFR 73.170 - Grape skin extract (enocianina).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Grape skin extract (enocianina). 73.170 Section 73... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.170 Grape skin extract (enocianina). (a) Identity. (1) The color additive grape skin extract (enocianina) is a purplish-red liquid prepared by...

  4. 21 CFR 73.170 - Grape skin extract (enocianina).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Grape skin extract (enocianina). 73.170 Section 73... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.170 Grape skin extract (enocianina). (a) Identity. (1) The color additive grape skin extract (enocianina) is a purplish-red liquid prepared by...

  5. 21 CFR 73.170 - Grape skin extract (enocianina).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Grape skin extract (enocianina). 73.170 Section 73... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.170 Grape skin extract (enocianina). (a) Identity. (1) The color additive grape skin extract (enocianina) is a purplish-red liquid prepared by...

  6. 21 CFR 73.170 - Grape skin extract (enocianina).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Grape skin extract (enocianina). 73.170 Section 73... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.170 Grape skin extract (enocianina). (a) Identity. (1) The color additive grape skin extract (enocianina) is a purplish-red liquid prepared by...

  7. Antibacterial effects of grape extracts on Helicobacter pylori.

    PubMed

    Brown, Joseph C; Huang, Guohui; Haley-Zitlin, Vivian; Jiang, Xiuping

    2009-02-01

    Anti-Helicobacter pylori activities were determined by agar dilution, confocal laser scanning microscopy, and cell proliferation assays following treatment with various grape extracts. Muscadine grape skin possessed the strongest activity, followed by grape synergy (skin and seed) and seed, suggesting that higher phenolic levels do not necessarily determine overall anti-H. pylori efficacy.

  8. Optimization of mechanical extraction conditions for producing grape seed oil

    USDA-ARS?s Scientific Manuscript database

    In the United States, over 150 thousand metric tons of dried grape seeds containing 13-19% of oil are produced every year, as a byproduct from processing of about 5.8 million metric tons of grapes. The health promoting properties of grape seed oil is due to the presence of many bioactive components ...

  9. 21 CFR 73.170 - Grape skin extract (enocianina).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Grape skin extract (enocianina). 73.170 Section 73... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.170 Grape skin extract (enocianina). (a) Identity. (1) The color additive grape skin extract (enocianina) is a purplish-red liquid prepared by the...

  10. 27 CFR 4.93 - Approval of grape variety names.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Approval of grape variety..., DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF WINE American Grape Variety Names § 4.93 Approval of grape variety names. (a) Any interested person may petition the Administrator for the...

  11. 27 CFR 4.93 - Approval of grape variety names.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Approval of grape variety..., DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF WINE American Grape Variety Names § 4.93 Approval of grape variety names. (a) Any interested person may petition the Administrator for the...

  12. 27 CFR 4.93 - Approval of grape variety names.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Approval of grape variety..., DEPARTMENT OF THE TREASURY ALCOHOL LABELING AND ADVERTISING OF WINE American Grape Variety Names § 4.93 Approval of grape variety names. (a) Any interested person may petition the Administrator for the...

  13. 27 CFR 4.93 - Approval of grape variety names.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Approval of grape variety..., DEPARTMENT OF THE TREASURY ALCOHOL LABELING AND ADVERTISING OF WINE American Grape Variety Names § 4.93 Approval of grape variety names. (a) Any interested person may petition the Administrator for the...

  14. 7 CFR 944.503 - Table Grape Import Regulation 4.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Table Grape Import Regulation 4. 944.503 Section 944...; IMPORT REGULATIONS § 944.503 Table Grape Import Regulation 4. (a)(1) Pursuant to section 8e of the Act... Vinifera species table grapes, except Emperor, Calmeria, Almeria, and Ribier varieties, is...

  15. 7 CFR 925.304 - California Desert Grape Regulation 6.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false California Desert Grape Regulation 6. 925.304 Section... SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE GRAPES GROWN IN A DESIGNATED AREA OF SOUTHEASTERN CALIFORNIA Assessment Rates § 925.304 California Desert Grape...

  16. 27 CFR 4.93 - Approval of grape variety names.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Approval of grape variety..., DEPARTMENT OF THE TREASURY LIQUORS LABELING AND ADVERTISING OF WINE American Grape Variety Names § 4.93 Approval of grape variety names. (a) Any interested person may petition the Administrator for the approval...

  17. 7 CFR 944.503 - Table Grape Import Regulation 4.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Table Grape Import Regulation 4. 944.503 Section 944...; IMPORT REGULATIONS § 944.503 Table Grape Import Regulation 4. (a)(1) Pursuant to section 8e of the Act... Vinifera species table grapes, except Emperor, Calmeria, Almeria, and Ribier varieties, is prohibited...

  18. Antibacterial Effects of Grape Extracts on Helicobacter pylori▿

    PubMed Central

    Brown, Joseph C.; Huang, Guohui; Haley-Zitlin, Vivian; Jiang, Xiuping

    2009-01-01

    Anti-Helicobacter pylori activities were determined by agar dilution, confocal laser scanning microscopy, and cell proliferation assays following treatment with various grape extracts. Muscadine grape skin possessed the strongest activity, followed by grape synergy (skin and seed) and seed, suggesting that higher phenolic levels do not necessarily determine overall anti-H. pylori efficacy. PMID:19047390

  19. Grapes on Steroids. Brassinosteroids Are Involved in Grape Berry Ripening1

    PubMed Central

    Symons, Gregory M.; Davies, Christopher; Shavrukov, Yuri; Dry, Ian B.; Reid, James B.; Thomas, Mark R.

    2006-01-01

    Fruit ripening is a unique plant developmental process with direct implications for our food supply, nutrition, and health. In contrast to climacteric fruit, where ethylene is pivotal, the hormonal control of ripening in nonclimacteric fruit, such as grape (Vitis vinifera), is poorly understood. Brassinosteroids (BRs) are steroidal hormones, essential for normal plant growth and development but not previously implicated in the ripening of nonclimacteric fruit. Here we show that increases in endogenous BR levels, but not indole-3-acetic acid (IAA) or GA levels, are associated with ripening in grapes. Putative grape homologs of genes encoding BR biosynthesis enzymes (BRASSINOSTEROID-6-OXIDASE and DWARF1) and the BR receptor (BRASSINOSTEROID INSENSITIVE 1) were isolated, and the function of the grape BRASSINOSTEROID-6-OXIDASE gene was confirmed by transgenic complementation of the tomato (Lycopersicon esculentum) extreme dwarf (dx/dx) mutant. Expression analysis of these genes during berry development revealed transcript accumulation patterns that were consistent with a dramatic increase in endogenous BR levels observed at the onset of fruit ripening. Furthermore, we show that application of BRs to grape berries significantly promoted ripening, while brassinazole, an inhibitor of BR biosynthesis, significantly delayed fruit ripening. These results provide evidence that changes in endogenous BR levels influence this key developmental process. This may provide a significant insight into the mechanism controlling ripening in grapes, which has direct implications for the logistics of grape production and down-stream processing. PMID:16361521

  20. Effects of different fungicide treatments on grape, must and wine quality.

    PubMed

    Lo Scalzo, R; Fibiani, M; Pietromarchi, P; Mandalà, C; La Torre, A

    2012-01-01

    The aim of this study was to evaluate the effectiveness of natural products and low-rate copper formulations against grapevine downy mildew, in order to reduce or replace copper use in organic farming, and to assess the effects on the qualitative parameters of grape, must and wine of the different treatments. The trial was carried out in an organic vineyard in accordance with the EPPO/OEPP guidelines. Plots were prepared, each containing 12 vine-plants and repeated four times in randomized blocks. At harvest, representative grape samples were picked off from the plots treated with the different products: for each treatment, a random sub-sample was kept for analyses, the remaining part was processed to produce wine. Grapes, musts and wines were characterized for their food quality indices, as well as for their nutraceutical profiles and antioxidant activity. On must and wine, sugars, acidity and pH were determined according to official methods. On grape and wine, total polyphenol, flavonoid and hydroxycinnamic acid contents were determined by spectrophotometric analysis, as well as antioxidant activity tests. Organic acids and single polyphenols were also determined by HPLC. The results of the trial, characterized by moderate infection pressure, indicate that all tested products guaranteed a satisfactory control of Plasmopara viticola although the alternatives to copper were not as effective as copper. Data evidence that grape quality and its oenological potential were not significantly influenced by applied treatments and that they did not significantly differ in comparison with the untreated control, only with an interesting significant negative correlation between proanthocyanidins level and the severity of disease on ripe berries. The uniformity of data seems to evidence a general adaptation of plants to different treatment stresses, probably due both to low input of active ingredients and to moderate downy mildew infection.

  1. Identification of a response regulator involved in surface attachment, cell-cell aggregation, exopolysaccharide production and virulence in the plant pathogen, Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa, the causal agent of Pierce’s disease of grapevines, possesses several two-component signal transduction systems that allow the bacterium to sense and respond to changes in its environment. Signals are perceived by sensor kinases that autophosphorylate and transfer the phosphate t...

  2. Lipopolysaccharide modulates the vector-pathogen interface of the xylem-limited phytopathogen, Xylella fastidiosa, the causal agent of Pierce’s disease of grapevine

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa Wells et al. is a gram-negative, insect-transmitted bacterium that causes a lethal disease of grapevine called Pierce’s disease. Lipopolysaccharide (LPS) is the most dominant macromolecule displayed on the cell surface of gram-negative bacteria. Bacterial interactions with the env...

  3. A TaqMan-based real time PCR assay for specific detection and quantification of Xylella fastidiosa strains causing bacterial leaf scorch in oleander

    USDA-ARS?s Scientific Manuscript database

    A TaqMan-based real-time PCR assay is developed for strains of X. fastidiosa causing oleander leaf scorch. The assay uses primers WG-OLS-F1 and WG-OLS-R1 and the fluorescent probe WG-OLS-P1, designed based on unique sequences present only in genomic sequence of oleander strain Ann1. The assay is spe...

  4. Development and systematic validation of qPCR assays for rapid and reliable differentiation of Xylella fastidiosa strains causing citrus variegated chlorosis

    USDA-ARS?s Scientific Manuscript database

    The xylem-limited, Gram-negative, fastidious plant bacterium Xylella fastidiosa is the causal agent of citrus variegated chlorosis (CVC), a destructive disease affecting approximately half of the citrus plantations in the State of São Paulo, Brazil. The disease was recently found in Central America...

  5. De Novo Whole-Genome Sequence of Xylella fastidiosa subsp. multiplex Strain BB01 Isolated from a Blueberry in Georgia, USA

    PubMed Central

    Van Horn, Christopher; Chang, Chung-Jan

    2017-01-01

    ABSTRACT This study reports a de novo-assembled draft genome sequence of Xylella fastidiosa subsp. multiplex strain BB01 causing blueberry bacterial leaf scorch in Georgia, USA. The BB01 genome is 2,517,579 bp, with a G+C content of 51.8%, 2,943 open reading frames (ORFs), and 48 RNA genes. PMID:28183766

  6. Spatiotemporal colonization of Xyllela fastidiosa in its vector supports two types of egestion in the inoculation mechanism of foregut-borne plant pathogens

    USDA-ARS?s Scientific Manuscript database

    The bacterial agent that causes Pierce’s disease of grapevine, Xylella fastidiosa, is the only known arthropod-transmitted prokaryotic plant pathogen that does not circulate in the vector’s hemolymph. Instead, bacteria are foregut-borne and semi-persistent, i.e. bacteria colonize cuticular surface...

  7. Muscle movements that control inoculation of Xylella fastidiosa are revealed by head X-rays of feeding glassy-winged sharpshooters

    USDA-ARS?s Scientific Manuscript database

    The mechanism of inoculation of the Pierce’s disease bacterium, Xylella fastidiosa (Xf), by vectors such as the glassy-winged sharpshooter (GWSS) is still unknown, despite nearly 70 years of study. Research in support of the egestion-salivation hypothesis for Xf inoculation is presented. Two impor...

  8. Mulberry strains of Xylella fastidiosa contain a 25 kilobase pair plasmid with extensive sequence identity to a plasmid from Verminephrobacter eiseniae

    USDA-ARS?s Scientific Manuscript database

    A 25 kbp plasmid was present in each of four Californian strains of Xylella fastidiosa from mulberry affected with leaf scorch disease. Fragments of each plasmid were cloned into E. coli, sequenced, and assembled into circular contigs of 25,105 bp (pXF-RIV11 and pXF-RIV16) or 24,372 bp (pXF-RIV19 an...

  9. Xylella fastidiosa isolates from mulberry harbor a 25 kilobase pair plasmid with extensive sequence identity to a plasmid from Verminephrobacter eiseniae

    USDA-ARS?s Scientific Manuscript database

    A 25 kbp plasmid was present in each of four Californian isolates of Xylella fastidiosa from mulberry affected with leaf scorch disease. Fragments of each plasmid were cloned into E. coli, sequenced, and assembled into circular contigs of 25,105 bp (pXF-RIV11 and pXF-RIV16) or 24,372 bp (pXF-RIV19 a...

  10. Host selection and adaptation are major driving forces shaping ALS Xylella fastidiosa population structure in the San Joaquin Valley of California

    USDA-ARS?s Scientific Manuscript database

    Xylella fastidiosa (Xf) causes disease in many commercial crops including almond leaf scorch (ALS) disease in susceptible almond (Prunus dulcis). In this study, genetic diversity and population structure of Xf associated with ALS disease were evaluated. Strains from two almond production sites in th...

  11. Plant water stress effects on stylet probing behaviors of Homalodisca vitripennis (Hemiptera: Cicadellidae) associated with acquisition and inoculation of the bacterium Xylella fastidiosa

    USDA-ARS?s Scientific Manuscript database

    The glassy-winged sharpshooter, Homalodisca vitripennis, is a xylem fluid-ingesting leafhopper that transmits Xylella fastidiosa, the causal agent of several plant diseases in the Americas. While the role of plant water stress on the population density and dispersal of H. vitripennis has been studie...

  12. Rationalization of pesticide treatments against powdery mildew of grape.

    PubMed

    Spera, G; La Torre, A; Gianferro, M; Bugliosi, R

    2007-01-01

    The powdery mildew represents one of the diseases which affect the grape, it is diffused in all agricultural regions with variable intensity and epidemic course in operation of many microclimatic factors. The powdery mildew of grape is caused from Uncinala necator (Schw.) Burr. (nowadays named Erysiphe necator Schwein.); it is controlled with systemic therapy and contact chemicaL products. In some vineyards located in Latium (central Italy), different field trials have been carried out purposely to rationalize the treatments against E. necator. We have studied the powdery mildew infections through monitoring a set of environmental parameters, the evaluation of cultivar sensibility, the agricultural production method and the area characteristics. We have analysed the following environmental parameters monitoring every 15 minutes: precipitation, soil temperature, solar radiation, wind direction, wind speed, atmospheric relative humidity, atmospheric temperature, leaf wetness, soil humidity to cm 20 and soil humidity to cm 40. Besides, we have used Artificial Intelligence analysis techniques to try to forecast U. necator infections. Guideline EPPO/OEPP PP 1/4 (4) has been used. The trials were conducted in conventional and organic farms. In 2 conventional farms and in organic farm we have considered 1 untreated control thesis, in order to follow the course of infection, 1 standard farm reference thesis (standard), where the treatments were carried out according to the usual farm procedures and 1 thesis where the treatments were carried out according to examining the environmental data. In another conventional vineyard, we have considered only 1 untreated control thesis and 1 standard farm reference thesis (standard) to study disease trend. The achieved results have underlined the possibility (through the knowledge of data pedoclimatic and cultural) to position the treatments against the powdery mildew so that to reduce their number. The lower number of treatments that

  13. Characterization of a Grape Class IV Chitinase

    PubMed Central

    2015-01-01

    A chitinase was purified from Vitis vinifera Manzoni Bianco grape juice and characterized. On the basis of proteomic analysis of tryptic peptides, a significant match identified the enzyme as a type IV grape chitinase previously found in juices of other V. vinifera varieties. The optimal pH and temperature for activity toward colloidal chitin were found to be 6 and 30 °C, respectively. The enzyme was found to hydrolyze chitin and oligomers of N-acetylglucosamine, generating N,N′-diacetylchitobiose and N-acetylglucosamine as products, but was inactive toward N,N′-diacetylchitobiose. The enzyme exhibited both endo- and exochitinase activities. Because yeast contains a small amount of chitin in the cell wall, the possibility of growth inhibition was tested. At a concentration and pH expected in ripe grapes, no inhibition of wine yeast growth by the chitinase was observed. PMID:24845689

  14. Functional Properties of Grape and Wine Polyphenols.

    PubMed

    Giovinazzo, Giovanna; Grieco, Francesco

    2015-12-01

    Grape berries polyphenols are mainly synthesized in the skin tissues and seeds and they are extracted during the winemaking process. These substances have a potentially positive effect, on human health, thus giving to grape and red wine "functional properties" that can contribute to prevent a number of human illness. Nevertheless, the research community is showing that the real effect is a result of a combination of different factors, notably daily intake, bioavailability, or in vivo antioxidant activity that are yet to be resolved. Viticulture and winemaking practices, determine the concentration of polyphenols in grape and wine. To date, reduced knowledge is existing on the effects of different yeast strains on the final concentration of polyphenols in red wine. We summarize the recent findings concerning the effects of polyphenols on human chronic disease and the future directions for research to increase the amount of these compounds in wine.

  15. Evolution and expression analysis of the grape (Vitis vinifera L.) WRKY gene family.

    PubMed

    Guo, Chunlei; Guo, Rongrong; Xu, Xiaozhao; Gao, Min; Li, Xiaoqin; Song, Junyang; Zheng, Yi; Wang, Xiping

    2014-04-01

    WRKY proteins comprise a large family of transcription factors that play important roles in plant defence regulatory networks, including responses to various biotic and abiotic stresses. To date, no large-scale study of WRKY genes has been undertaken in grape (Vitis vinifera L.). In this study, a total of 59 putative grape WRKY genes (VvWRKY) were identified and renamed on the basis of their respective chromosome distribution. A multiple sequence alignment analysis using all predicted grape WRKY genes coding sequences, together with those from Arabidopsis thaliana and tomato (Solanum lycopersicum), indicated that the 59 VvWRKY genes can be classified into three main groups (I-III). An evaluation of the duplication events suggested that several WRKY genes arose before the divergence of the grape and Arabidopsis lineages. Moreover, expression profiles derived from semiquantitative PCR and real-time quantitative PCR analyses showed distinct expression patterns in various tissues and in response to different treatments. Four VvWRKY genes showed a significantly higher expression in roots or leaves, 55 responded to varying degrees to at least one abiotic stress treatment, and the expression of 38 were altered following powdery mildew (Erysiphe necator) infection. Most VvWRKY genes were downregulated in response to abscisic acid or salicylic acid treatments, while the expression of a subset was upregulated by methyl jasmonate or ethylene treatments.

  16. Evolution and expression analysis of the grape (Vitis vinifera L.) WRKY gene family

    PubMed Central

    Guo, Chunlei; Guo, Rongrong; Wang, Xiping

    2014-01-01

    WRKY proteins comprise a large family of transcription factors that play important roles in plant defence regulatory networks, including responses to various biotic and abiotic stresses. To date, no large-scale study of WRKY genes has been undertaken in grape (Vitis vinifera L.). In this study, a total of 59 putative grape WRKY genes (VvWRKY) were identified and renamed on the basis of their respective chromosome distribution. A multiple sequence alignment analysis using all predicted grape WRKY genes coding sequences, together with those from Arabidopsis thaliana and tomato (Solanum lycopersicum), indicated that the 59 VvWRKY genes can be classified into three main groups (I–III). An evaluation of the duplication events suggested that several WRKY genes arose before the divergence of the grape and Arabidopsis lineages. Moreover, expression profiles derived from semiquantitative PCR and real-time quantitative PCR analyses showed distinct expression patterns in various tissues and in response to different treatments. Four VvWRKY genes showed a significantly higher expression in roots or leaves, 55 responded to varying degrees to at least one abiotic stress treatment, and the expression of 38 were altered following powdery mildew (Erysiphe necator) infection. Most VvWRKY genes were downregulated in response to abscisic acid or salicylic acid treatments, while the expression of a subset was upregulated by methyl jasmonate or ethylene treatments. PMID:24510937

  17. Attachment of Agrobacteria to Grape Cells †

    PubMed Central

    Pu, Xin-An; Goodman, R. N.

    1993-01-01

    The presence of the Ti plasmid favorably influences the attachment of agrobacteria to grape callus cells, especially during the early stages of a 2-h incubation. Agrobacterium strains attached to a similar extent to both the crown gall-resistant cultivar (Catawba), Vitis labruscana, and the crown gall-susceptible cultivar (Chancellor), Vitis sp. Attachment of the virulent strain to grape callus cells is blocked by the avirulent strain HLB-2 in both the tissue culture cell suspension and the seedling root systems. PMID:16349016

  18. Ochratoxin A in grape juice and wine.

    PubMed

    Woese, K

    2000-03-01

    37 different grape juices and 21 red wines were analyzed for their contents of ochratoxin A at the State's Veterinary and Food Research Institute of Saxony-Anhalt in Halle in 1999 and the 1(st) quarter of 2000. Ochratoxin A was found in 78 % of the grape juices and 100 % of the wines. 27 % or 33 % respectively exceeded the EC Commission's lately intended proposal for an ochratoxin A maximum permissible level which is 0.5 ppb. A higher contamination rate for wines originating from southern growing regions of the EC was noticeable.

  19. Crystallization and preliminary X-ray diffraction analysis of a glutathione S-transferase from Xylella fastidiosa

    SciTech Connect

    Garcia, Wanius; Travensolo, Regiane F.; Rodrigues, Nathalia C.; Muniz, João R. C.; Caruso, Célia S.; Lemos, Eliana G. M.; Araujo, Ana Paula U.; Carrilho, Emanuel

    2008-02-01

    Glutathione S-transferase from X. fastidiosa (xfGST) has been overexpressed in E. coli, purified and crystallized. Diffraction data were collected to 2.23 Å. Glutathione S-transferases (GSTs) form a group of multifunctional isoenzymes that catalyze the glutathione-dependent conjugation and reduction reactions involved in the cellular detoxification of xenobiotic and endobiotic compounds. GST from Xylella fastidiosa (xfGST) was overexpressed in Escherichia coli and purified by conventional affinity chromatography. In this study, the crystallization and preliminary X-ray analysis of xfGST is described. The purified protein was crystallized by the vapour-diffusion method, producing crystals that belonged to the triclinic space group P1. The unit-cell parameters were a = 47.73, b = 87.73, c = 90.74 Å, α = 63.45, β = 80.66, γ = 94.55°. xfGST crystals diffracted to 2.23 Å resolution on a rotating-anode X-ray source.

  20. Xylella fastidiosa plasmid-encoded PemK toxin is an endoribonuclease.

    PubMed

    Lee, Min Woo; Rogers, Elizabeth E; Stenger, Drake C

    2012-01-01

    Stable inheritance of pXF-RIV11 in Xylella fastidiosa is conferred by the pemI/pemK toxin-antitoxin (TA) system. PemK toxin inhibits bacterial growth; PemI is the corresponding antitoxin that blocks activity of PemK by direct binding. PemK and PemI were overexpressed in Escherichia coli and activities of each were assessed. Purified PemK toxin specifically degraded single-stranded RNA but not double-stranded RNA, double-stranded DNA, or single-stranded DNA. Addition of PemI antitoxin inhibited nuclease activity of PemK toxin. Purified complexes of PemI bound to PemK exhibited minimal nuclease activity; removal of PemI antitoxin from the complex restored nuclease activity of PemK toxin. Sequencing of 5' rapid amplification of cDNA ends products of RNA targets digested with PemK revealed a preference for cleavage between U and A residues of the sequence UACU and UACG. Nine single amino-acid substitution mutants of PemK toxin were constructed and evaluated for growth inhibition, ribonuclease activity, and PemI binding. Three PemK point-substitution mutants (R3A, G16E, and D79V) that lacked nuclease activity did not inhibit growth. All nine PemK mutants retained the ability to bind PemI. Collectively, the results indicate that the mechanism of stable inheritance conferred by pXF-RIV11 pemI/pemK is similar to that of the R100 pemI/pemK TA system of E. coli.

  1. Persistence of Azoxystrobin in/on Grapes and Soil in Different Grapes Growing Areas of India

    PubMed Central

    Gajbhiye, Vijay Tularam; Gupta, Suman; Mukherjee, Irani; Singh, Shashi Bala; Singh, Neera; Kumar, Yogesh

    2010-01-01

    Persistence of azoxystrobin was studied in/on grapes when applied @ 150 g ai ha−1 (recommended dose) and 300 g ai ha−1 (double the recommended dose) in three grapes growing states of India, namely Karnataka, Maharashtra and Tamil Nadu, in the year 2006–2007. A total of five sprays were given at an interval of about 15 days. Grapes and soil samples were collected after 5th spray, extracted and analysed by gas chromatography using electron capture detector. Half life of azoxystrobin on grapes varied from 5.4 to 11.2 days. Residues of azoxystrobin were much below the prescribed MRL (0.5 mg kg−1) after 21 days. The dissipation of azoxystrobin in soil followed first order rate kinetics with an average half life of 8.1 days at the recommended dose of application. PMID:21153804

  2. Infection

    DTIC Science & Technology

    2010-09-01

    standing, diagnosis, and treatment of musculoskeletal infections. Key Words: musculoskeletal infection, biofilm , bacteria, biomaterial (J Orthop Trauma...form a biofilm , or slime layer.1 The recurrence of infections is often the result of microbial biofilm formation on the implant, enabling the persistence...Klebsiella pneumoniae). Staphylococcus species is by far the most studied pathogen in musculoskeletal infections and can produce a multilayered biofilm

  3. Type 2 diabetes and glycemic response to grapes or grape products.

    PubMed

    Zunino, Susanj

    2009-09-01

    Type 2 diabetes affects approximately 7% of the population in the United States and is characterized by decreased disposal of glucose in peripheral tissues due to insulin resistance and overproduction of glucose by the liver, defects in pancreatic beta-cell function, and decreased beta-cell mass. Obesity, decreased physical exercise, and consumption of foods with a high glycemic index (GI) and load are major predisposing factors in the development of type 2 diabetes. The GI is used to evaluate the rise in blood glucose levels in response to food. The GI provides an indication of the quality of carbohydrate in a food. The glycemic load (GL) is used to provide information about the quantity of carbohydrates in a food and the insulin demand. Individuals with diabetes are advised to maintain a diet of low-GL foods, because low-GL diets improve diabetes symptoms. Grapes have a mean GI and GL in the low range. Little research has been performed with grapes and/or grape products to determine the glycemic response either alone or with a meal. Grapes and other fruits contain numerous polyphenols, including the stilbene resveratrol, the flavanol quercetin, catechins, and anthocyanins that have shown potential for reducing hyperglycemia, improving beta-cell function, and protecting against beta-cell loss. Therefore, with a low mean GI and GL, grapes or grape products may provide health benefits to type 2 diabetics.

  4. Anticancer and cancer chemopreventive potential of grape seed extract and other grape-based products.

    PubMed

    Kaur, Manjinder; Agarwal, Chapla; Agarwal, Rajesh

    2009-09-01

    With emerging trends in the incidence of cancer of various organ sites, additional approaches are needed to control human malignancies. Intervention or prevention of cancer by dietary constituents, a strategy defined as chemoprevention, holds great promise in our conquest to control cancer, because it can be implemented on a broader population base with less economic burden. Consistent with this, several epidemiological studies have shown that populations that consume diets rich in fruits and vegetables have an overall lower cancer incidence. Based on these encouraging observations, research efforts from across the globe have focused on identifying, characterizing, and providing scientific basis to the efficacy of various phytonutrients in an effort to develop effective strategy to control various human malignancies. Cancer induction, growth, and progression are multi-step events and numerous studies have demonstrated that various dietary agents interfere with these stages of cancer, thus blocking malignancy. Fruits and vegetables represent untapped reservoir of various nutritive and nonnutritive phytochemicals with potential cancer chemopreventive activity. Grapes and grape-based products are one such class of dietary products that have shown cancer chemopreventive potential and are also known to improve overall human health. This review focuses on recent advancements in cancer chemopreventive and anticancer efficacy of grape seed extract and other grape-based products. Overall, completed studies from various scientific groups conclude that both grapes and grape-based products are excellent sources of various anticancer agents and their regular consumption should thus be beneficial to the general population.

  5. Impact of foliar symptoms of "Esca proper" on proteins related to defense and oxidative stress of grape skins during ripening.

    PubMed

    Pasquier, Grégory; Lapaillerie, Delphine; Vilain, Sébastien; Dupuy, Jean-William; Lomenech, Anne-Marie; Claverol, Stéphane; Gény, Laurence; Bonneu, Marc; Teissedre, Pierre-Louis; Donèche, Bernard

    2013-01-01

    Esca is one of the major diseases affecting vineyards with direct impact on product yield; nevertheless, scientific studies concerning its impact on grape quality are scarce. As an attempt to better understand the mechanisms behind "Esca proper" development in grapes, this work focused on the identification of proteins whose expression is altered by the disease. 2-DEs were performed on protein extracts from grape skins at different stages of maturity for two consecutive vintages. Grapes were collected in 2009 and in 2010 from plants that did not present signs of infection by Esca proper since the 2004 vintage and from plants that presented cast leaf symptoms at least once since 2004. For the first time, 13 proteins were shown to be influenced by Esca proper during the ripening process. Extensive bioinformatics analysis allowed the grouping of proteins involved in (i) stress tolerance and defense response, (ii) oxidative phosphorylation, (iii) oxidation-reduction processes in mitochondria, and (iv) oxidation-reduction processes in chloroplasts. Of these 13 proteins, cysteine synthase is the only one implicated in a metabolic pathway of oenological interest. This study shows how foliar symptoms of Esca proper may impact stress-related pathways in grapes, which are characterized by modifications in the chain of oxidative phosphorylation and redox scavenging.

  6. Anthocyanin Profiles in Flowers of Grape Hyacinth.

    PubMed

    Lou, Qian; Wang, Lin; Liu, Hongli; Liu, Yali

    2017-04-26

    Grape hyacinth (Muscari spp.) is a popular ornamental bulbous perennial famous for its blue flowers. To understand the chemical basis of the rich blue colors in this plant, anthocyanin profiles of six blue flowering grape hyacinths as well as one pink and one white cultivar were determined using high-performance liquid chromatography and mass spectrometry. Along with two known compounds, eight putative anthocyanins were identified in the tepals of grape hyacinth for the first time. The accumulation and distribution of anthocyanins in the plant showed significant cultivar and flower development specificity. Violet-blue flowers mainly contained simple delphinidin-type anthocyanins bearing one or two methyl-groups but no acyl groups, whereas white and pink flowers synthesised more complex pelargonidin/cyanidin-derivatives with acyl-moieties but no methyl-groups. The results partially reveal why solid blue, orange or red flowers are rare in this plant in nature. In addition, pelargonidin-type anthocyanins were found for the first time in the genus, bringing more opportunities in terms of breeding of flower color in grape hyacinth.

  7. Inoculum detection for managing grape powdery mildew

    USDA-ARS?s Scientific Manuscript database

    Grape powdery mildew (caused by Erysiphe necator) often develops explosively and can result in significant yield and quality losses, despite your best efforts. The threat of quality losses often leads to a low risk prophylactic regimen rather than a higher risk IPM approach. Gary Grove and I have co...

  8. Characterization of polyphenolic metabolites in grape hybrids

    USDA-ARS?s Scientific Manuscript database

    The composition and content of polyphenolic compounds in the berries of 48 hybrid grapes (Vitis) were characterized for two consecutive years. A total of 48 polyphenolic compounds including 28 anthocyanins, 2 hydroxybenzoic acids, 6 hydroxycinnamic derivatives, 6 flavonols and 6 flavanols were ident...

  9. VitisGen: accelerating grape cultivar improvement

    USDA-ARS?s Scientific Manuscript database

    VitisGen is a multiple institute collaborative project funded by the USDA SCRI program, with a long term goal to accelerate grape cultivar improvement by using cutting-edge molecular marker technologies, rigorous centralized facilities to characterize traits, and molecular breeding expertise. The ge...

  10. Genomics Assisted Ancestry Deconvolution in Grape

    PubMed Central

    Sawler, Jason; Reisch, Bruce; Aradhya, Mallikarjuna K.; Prins, Bernard; Zhong, Gan-Yuan; Schwaninger, Heidi; Simon, Charles; Buckler, Edward; Myles, Sean

    2013-01-01

    The genus Vitis (the grapevine) is a group of highly diverse, diploid woody perennial vines consisting of approximately 60 species from across the northern hemisphere. It is the world’s most valuable horticultural crop with ~8 million hectares planted, most of which is processed into wine. To gain insights into the use of wild Vitis species during the past century of interspecific grape breeding and to provide a foundation for marker-assisted breeding programmes, we present a principal components analysis (PCA) based ancestry estimation method to calculate admixture proportions of hybrid grapes in the United States Department of Agriculture grape germplasm collection using genome-wide polymorphism data. We find that grape breeders have backcrossed to both the domesticated V. vinifera and wild Vitis species and that reasonably accurate genome-wide ancestry estimation can be performed on interspecific Vitis hybrids using a panel of fewer than 50 ancestry informative markers (AIMs). We compare measures of ancestry informativeness used in selecting SNP panels for two-way admixture estimation, and verify the accuracy of our method on simulated populations of admixed offspring. Our method of ancestry deconvolution provides a first step towards selection at the seed or seedling stage for desirable admixture profiles, which will facilitate marker-assisted breeding that aims to introgress traits from wild Vitis species while retaining the desirable characteristics of elite V. vinifera cultivars. PMID:24244717

  11. Biodiversity of complexes of mycotoxigenic fungal species associated with Fusarium ear rot of maize and Aspergillus rot of grape.

    PubMed

    Logrieco, A; Moretti, A; Perrone, G; Mulè, G

    2007-10-20

    Fusarium ear rot of maize and Aspergillus rot of grape are two examples of important plant diseases caused by complexes of species of mycotoxigenic fungi. These complexes of species tend to be closely related, produce different classes of mycotoxins, and can induce disease under different environmental conditions. The infection of maize and grape with multiple fungal species and the resulting production of large classes of mycotoxins is an example of mutual aggressiveness of microorganisms toward host species as well as to humans and animals that eat feed or food derived from the infected and contaminated plants. Infection of crop plant with a complex of microbial species certainly represents a greater threat to a crop plant and to human and animal health than infection of the plant with a single fungal species.

  12. Effect of cuticular waxes compounds from table grapes on growth, germination and gene expression in Botrytis cinerea.

    PubMed

    Silva-Moreno, Evelyn; Brito-Echeverría, Jocelyn; López, Miguel; Ríos, Juan; Balic, Iván; Campos-Vargas, Reinaldo; Polanco, Rubén

    2016-05-01

    Botrytis cinerea attacks a broad range of host causing significant economic losses in the worldwide fruit export industry. Hitherto, many studies have focused on the penetration mechanisms used by this phytopathogen, but little is known about the early stages of infection, especially those such as adhesion and germination. The aim of this work was to evaluate the effect of cuticular waxes compounds from table grapes on growth, germination and gene expression of B. cinerea. To accomplish this, growth was analyzed using as substrate n-alkanes extracted from waxes of fresh fruit (table grapes, blueberries and apricots). Subsequently, the main compounds of table grape waxes, oleanolic acid (OA) and n-fatty alcohols, were mixed to generate a matrix on which conidia of B. cinerea were added to assess their effect on germination and expression of bctub, bchtr and bchex genes. B. cinerea B05.10, isolated from grapes, increased its growth on a matrix composed by table grapes n-alkanes in comparison to a matrix made with n-alkanes from apricot or blueberries. Moreover, at 2.5 h, B05.10 germination increased 17 and 33 % in presence of n-alkanes from table grape, in comparison to conditions without alkanes or with blueberries alkanes, respectively. Finally, expression of bchtr and bchex showed a significant increase during the first hour after contact with n-fatty alcohols and OA. In conclusion, B. cinerea displays selectivity towards certain compounds found in host waxes, mainly n-fatty alcohols, which could be a good candidate to control this phytopathogen in early stages of infection.

  13. Environmental factors affect the activity of biocontrol agents against ochratoxigenic Aspergillus carbonarius on wine grape.

    PubMed

    De Curtis, F; de Felice, D V; Ianiri, G; De Cicco, V; Castoria, R

    2012-09-17

    The influence of temperature and relative humidity (RH) on the activity of three biocontrol agents-the yeast Metschnikowia pulcherrima LS16 and two strains of the yeast-like fungus Aureobasidium pullulans LS30 and AU34-2-against infection by A. carbonarius and ochratoxin A (OTA) accumulation in wine grape berries was investigated in lab-scale experiments. The presence of wounds on grape skin dramatically favored infection of berries by A. carbonarius strain A1102, since unwounded berries showed very low levels of infection at all conditions of RH and temperature tested. Artificially wounded berries pre-treated with the biocontrol agents were inoculated with the ochratoxigenic A. carbonarius strain A1102 and were incubated for 5 days at two levels of RH (60% and 100%) and three different temperatures (20, 25 and 30 °C). The three biocontrol agents were able to prevent infections at 60% RH and 20 °C. At 60% RH and 25 °C only strain AU34-2 achieved some protection on day 5, whereas at 30 °C a limited biocontrol efficacy was evident only up to day 2. At 100% RH, LS16, LS30 and AU34-2 showed effective protection of grape berries at 20 °C until the 5th day of incubation. The three biocontrol agents achieved significant protection at higher temperatures only until the 2nd day after the beginning of the experiment: all three strains at 25 °C, and only strain LS16 at 30 °C. After 5 days, the three biocontrol agents were able to significantly reduce the level of OTA in berries at all the conditions tested. This occurred even when protection from infection was not significant, except at 30 °C and 100% of RH for all the three strains, and at 25 °C and 100% of RH for strain LS16. The biocontrol agents displayed a higher rate of colonization on grape berries at 20 and 25 °C than at 30 °C. The higher value of RH (100%) appeared to increase the rate of colonization, in particular at 20 and 25 °C. Taken together, our results emphasize the significant influence of

  14. Analysis of the genome-wide variations among multiple strains of the plant pathogenic bacterium Xylella fastidiosa.

    PubMed

    Doddapaneni, Harshavardhan; Yao, Jiqiang; Lin, Hong; Walker, M Andrew; Civerolo, Edwin L

    2006-09-01

    The Gram-negative, xylem-limited phytopathogenic bacterium Xylella fastidiosa is responsible for causing economically important diseases in grapevine, citrus and many other plant species. Despite its economic impact, relatively little is known about the genomic variations among strains isolated from different hosts and their influence on the population genetics of this pathogen. With the availability of genome sequence information for four strains, it is now possible to perform genome-wide analyses to identify and categorize such DNA variations and to understand their influence on strain functional divergence. There are 1,579 genes and 194 non-coding homologous sequences present in the genomes of all four strains, representing a 76. 2% conservation of the sequenced genome. About 60% of the X. fastidiosa unique sequences exist as tandem gene clusters of 6 or more genes. Multiple alignments identified 12,754 SNPs and 14,449 INDELs in the 1528 common genes and 20,779 SNPs and 10,075 INDELs in the 194 non-coding sequences. The average SNP frequency was 1.08 x 10(-2) per base pair of DNA and the average INDEL frequency was 2.06 x 10(-2) per base pair of DNA. On an average, 60.33% of the SNPs were synonymous type while 39.67% were non-synonymous type. The mutation frequency, primarily in the form of external INDELs was the main type of sequence variation. The relative similarity between the strains was discussed according to the INDEL and SNP differences. The number of genes unique to each strain were 60 (9a5c), 54 (Dixon), 83 (Ann1) and 9 (Temecula-1). A sub-set of the strain specific genes showed significant differences in terms of their codon usage and GC composition from the native genes suggesting their xenologous origin. Tandem repeat analysis of the genomic sequences of the four strains identified associations of repeat sequences with hypothetical and phage related functions. INDELs and strain specific genes have been identified as the main source of variations

  15. Description of a taxonomically undefined Sclerotiniaceae strain from withered rotten-grapes.

    PubMed

    Lorenzini, Marilinda; Zapparoli, Giacomo

    2016-02-01

    A necrotrophic member of the Sclerotiniaceae family (herewith named strain C10) isolated from withered rotten-grapes, is described. Interestingly, the fungus has no defined taxonomic position since it has been impossible to attribute it to an existing genus. Phylogenetic analysis of partial sequences of glyceraldehyde 3-phosphate dehydrogenase (G3PDH), heat shock protein 60 (HSP60) and DNA-directed RNA polymerase II subunit (RPB2), revealed that strain C10 is distantly related to Amphobotrys and Botrytis. This evidence clearly distinguishes this new Sclerotiniaceae member from other taxa of the family. Moreover, its morphological characteristics did not match those of Amphobotrys and Botrytis. Infectivity assays demonstrated that strain C10 could be a potential postharvest pathogen of withered grapes. This study revealed the taxonomic importance of this strain suggesting the existence of a possible new genus, a theory that requires further investigation.

  16. Concord grape juice supplementation and neurocognitive function in human aging.

    PubMed

    Krikorian, Robert; Boespflug, Erin L; Fleck, David E; Stein, Amanda L; Wightman, Jolynne D; Shidler, Marcelle D; Sadat-Hossieny, Sara

    2012-06-13

    Polyphenol compounds found in berry fruits, in particular flavonoids, have been associated with health benefits including improvement in cognition and neuronal function with aging. Concord grape juice contains polyphenols, including anthocyanins and flavanols, and previous research has shown improvement in a number of human health conditions with grape juice supplementation. In the current study, older adult subjects with mild cognitive impairment consumed Concord grape juice or placebo for 16 weeks and were administered assessments of memory function and brain activation pre- and postintervention. Participants who consumed grape juice showed reduced semantic interference on memory tasks. Relatively greater activation in anterior and posterior regions of the right hemisphere was also observed with functional magnetic resonance imaging in the grape juice treated subjects. These findings provide further evidence that Concord grape juice can enhance neurocognitive function in older adults with mild memory decline.

  17. Yield-based economic thresholds for grape berry moth (Lepidoptera: Tortricidae) in juice grapes.

    PubMed

    Roubos, Craig R; Mason, Keith S; Teixeira, Luís A F; Isaacs, Rufus

    2013-04-01

    A 3-yr field study was conducted at commercial juice grape (Vitis labrusca L.) vineyards to develop an economic injury level (EIL) for grape berry moth, Paralobesia viteana (Clemens) (Lepidoptera: Tortricidae) and to determine patterns of cluster injury. Infestation of grape clusters by P. viteana was measured biweekly from bloom until harvest, and fruit was sampled immediately before harvest to determine the yield and level of fruit injury by this pest. Comparison of fruit infestation at each sampling date to that found just before harvest revealed stronger relationships over time, and by early August at least 50% of the variation in preharvest infestation was accounted for by previous infestation. Grape yield declined with increasing infestation by P. viteana, allowing calculation of the EIL at which the value of yield lost to infestation equaled the cost of insecticide applications to prevent the infestation. Using two scenarios of pest control programs based on pyrethroid or diamide insecticides, the EILs were calculated to be 9.9 and 17.7% of clusters damaged, respectively. For use in juice grape vineyard integrated pest management programs, we propose using 5 and 10% damaged clusters at harvest as action thresholds for further testing in field trials to evaluate sampling plans and the use of thresholds to guide vineyard pest management decision-making under different insecticide scenarios.

  18. Crystallization and preliminary X-ray diffraction analysis of a glutathione S-transferase from Xylella fastidiosa

    PubMed Central

    Garcia, Wanius; Travensolo, Regiane F.; Rodrigues, Nathalia C.; Muniz, João R. C.; Caruso, Célia S.; Lemos, Eliana G. M.; Araujo, Ana Paula U.; Carrilho, Emanuel

    2008-01-01

    Glutathione S-transferases (GSTs) form a group of multifunctional isoenzymes that catalyze the glutathione-dependent conjugation and reduction reactions involved in the cellular detoxification of xenobiotic and endobiotic compounds. GST from Xylella fastidiosa (xfGST) was overexpressed in Escherichia coli and purified by conventional affinity chromatography. In this study, the crystallization and preliminary X-ray analysis of xfGST is described. The purified protein was crystallized by the vapour-diffusion method, producing crystals that belonged to the triclinic space group P1. The unit-cell parameters were a = 47.73, b = 87.73, c = 90.74 Å, α = 63.45, β = 80.66, γ = 94.55°. xfGST crystals diffracted to 2.23 Å resolution on a rotating-anode X-ray source. PMID:18259055

  19. Total phenolic contents and free-radical scavenging activities of grape (Vitis vinifera L.) and grape products.

    PubMed

    Keser, Serhat; Celik, Sait; Turkoglu, Semra

    2013-03-01

    Grape is one of the world's largest fruit crops, with an approximate annual production of 58 million metric tons, and it is well known that the grape skins, seeds and stems, waste products generated during wine and grape juice processing, are rich sources of polyphenols. It contains flavonoids, phenolic acids and stilbenes. In this study, we tried to determine antioxidant properties and phenolic contents of grape and grape products (fresh fruit, seed, dried fruit, molasses, pestil, vinegar) of ethanol and water extracts. Antioxidant properties of extracts were investigated by DPPH(√), ABTS(√+), superoxide, H(2)O(2) scavenging, reducing power, metal chelating activity and determination of total phenolic contents. The seed extracts revealed highest ABTS(√+), DPPH(√), H(2)O(2) scavenging and reducing power activities. Furthermore, these extracts showed higher total phenolic contents than other grape product extracts.

  20. Recent advances and uses of grape flavonoids as nutraceuticals.

    PubMed

    Georgiev, Vasil; Ananga, Anthony; Tsolova, Violeta

    2014-01-21

    Grape is one of the oldest fruit crops domesticated by humans. The numerous uses of grape in making wine, beverages, jelly, and other products, has made it one of the most economically important plants worldwide. The complex phytochemistry of the berry is characterized by a wide variety of compounds, most of which have been demonstrated to have therapeutic or health promoting properties. Among them, flavonoids are the most abundant and widely studied, and have enjoyed greater attention among grape researchers in the last century. Recent studies have shown that the beneficial health effects promoted by consumption of grape and grape products are attributed to the unique mix of polyphenolic compounds. As the largest group of grape polyphenols, flavonoids are the main candidates considered to have biological properties, including but not limited to antioxidant, anti-inflammatory, anti-cancer, antimicrobial, antiviral, cardioprotective, neuroprotective, and hepatoprotective activities. Here, we discuss the recent scientific advances supporting the beneficial health qualities of grape and grape-derived products, mechanisms of their biological activity, bioavailability, and their uses as nutraceuticals. The advantages of modern plant cell based biotechnology as an alternative method for production of grape nutraceuticals and improvement of their health qualities are also discussed.

  1. Recent Advances and Uses of Grape Flavonoids as Nutraceuticals

    PubMed Central

    Georgiev, Vasil; Ananga, Anthony; Tsolova, Violeta

    2014-01-01

    Grape is one of the oldest fruit crops domesticated by humans. The numerous uses of grape in making wine, beverages, jelly, and other products, has made it one of the most economically important plants worldwide. The complex phytochemistry of the berry is characterized by a wide variety of compounds, most of which have been demonstrated to have therapeutic or health promoting properties. Among them, flavonoids are the most abundant and widely studied, and have enjoyed greater attention among grape researchers in the last century. Recent studies have shown that the beneficial health effects promoted by consumption of grape and grape products are attributed to the unique mix of polyphenolic compounds. As the largest group of grape polyphenols, flavonoids are the main candidates considered to have biological properties, including but not limited to antioxidant, anti-inflammatory, anti-cancer, antimicrobial, antiviral, cardioprotective, neuroprotective, and hepatoprotective activities. Here, we discuss the recent scientific advances supporting the beneficial health qualities of grape and grape-derived products, mechanisms of their biological activity, bioavailability, and their uses as nutraceuticals. The advantages of modern plant cell based biotechnology as an alternative method for production of grape nutraceuticals and improvement of their health qualities are also discussed. PMID:24451310

  2. Thermal degradation of grape marc polyphenols.

    PubMed

    Sólyom, Katalin; Solá, Ruth; Cocero, María José; Mato, Rafael B

    2014-09-15

    Bioactive compounds of wine making by-products are of interest in food, cosmetics and pharmaceutical industries. Extraction of antioxidants under mild conditions is time-consuming, giving ground to the development of intensification processes where the operation at high temperature may deteriorate extract quality. This study examined thermal degradation of grape marc and its filtered extract (80, 100 and 150°C). The decrease in anthocyanin content was modelled under non-isothermal conditions by first order kinetics, using the Arrhenius equation. Simulated degradation under isothermal heating showed that the grape marc is more sensitive by one order of magnitude to heat than the filtered extract. This tendency was also confirmed by analyses of the total phenolic content and antioxidant activity. It is suggested that an optimal combination of temperature, treatment time and also raw material environment could be found in process intensification. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Copper transport and compartmentation in grape cells.

    PubMed

    Martins, Viviana; Hanana, Mohsen; Blumwald, Eduardo; Gerós, Hernâni

    2012-11-01

    Copper-based fungicides have been widely used against several grapevine (Vitis vinifera L.) diseases since the late 1800s when the Bordeaux mixture was developed, but their intensive use has raised phytotoxicity concerns. In this study, physiological, biochemical and molecular approaches were combined to investigate the impacts of copper in grape cells and how it is transported and compartmented intracellularly. Copper reduced the growth and viability of grape cells (CSB, Cabernet Sauvignon Berry) in a dose-dependent manner above 100 µM and was accumulated in specific metal ion sinks. The copper-sensitive probe Phen Green SK was used to characterize copper transport across the plasma membrane of CSB cells. The transport system (K(m) = 583 µM; V(max) = 177 × 10(-6) %ΔF min(-1) protoplast(-1)) was regulated by copper availability in the culture medium, stimulated by Ca(2+) and inhibited by Zn(2+). The pH-sensitive fluorescent probe ACMA (9-amino-6-chloro-2-methoxyacridine) was used to evaluate the involvement of proton-dependent copper transport across the tonoplast. Cu(2+) compartmentation in the vacuole was dependent on the transmembrane pH gradient generated by both V-H(+)-ATPase and V-H(+)-pyrophosphatase (PPase). High copper levels in the growth medium did not affect the activity of V-H(+)-PPase but decreased the magnitude of the H(+) gradient generated by V-H(+)-ATPase. Expression studies of VvCTr genes showed that VvCTr1 and VvCTr8 were distinctly affected by CuSO(4) availability in grape cell cultures and that both genes were highly expressed in the green stage of grape berries.

  4. Response of direct or priming defense against Botrytis cinerea to methyl jasmonate treatment at different concentrations in grape berries.

    PubMed

    Wang, Kaituo; Liao, Yunxia; Kan, Jianquan; Han, Lin; Zheng, Yonghua

    2015-02-02

    This study was conducted to characterize the forms of disease resistance induced by methyl jasmonate (MeJA) in harvested grape berries and to evaluate the impact of the induced resistance on fruit quality. The results showed that MeJA treatment at concentrations from 10 to 100μmol/L could effectively induce disease resistance against Botrytis cinerea and reduce disease incidence in grape berries. The induced disease resistance was tightly associated with increased H2O2 generation, enhanced expression of the defense-related gene VvNPR1.1 and accumulation of stilbene phytoalexins such as tran-resveratrol and its oligomer (trans-)ε-viniferin. The expression of the defense-related gene and synthesis of phytoalexins in 10μmol/L MeJA-treated grape berries were only significantly enhanced upon inoculating the berries with B. cinerea, whereas the 50 or 100μmol/L of MeJA treatment directly induced these defense responses. Hence, we deduce that the low concentration of MeJA (10μmol/L) triggered a priming defense mechanism, while higher concentrations of MeJA (50 or 100μmol/L) directly activated defense responses, thus enhancing disease resistance in grape berries. Moreover, the primed grape berries maintained higher contents of soluble sugars and higher DPPH radical scavenging activity and reducing power compared with those expressing direct defense responses. These results indicate that priming of defense is a cost-effective strategy to protect harvested grape berries from B. cinerea infection in terms of minimizing quality loss. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. PemK toxin encoded by the Xylella fastidiosa IncP-1 plasmid pXF-RIV11 is a ribonuclease

    USDA-ARS?s Scientific Manuscript database

    Stable inheritance of the IncP-1 plasmid pXF-RIV11 in Xylella fastidiosa is conferred by the pemI/pemK plasmid addiction system. PemK serves as a toxin inhibiting bacterial growth; PemI is the corresponding antitoxin that blocks activity of PemK toxin by direct binding. Here, PemK toxin and PemI ant...

  6. Light exclusion influence on grape anthocyanin.

    PubMed

    Lee, Jungmin

    2017-02-01

    This study contrasted the anthocyanins of investigational grape clusters that developed without light incidence (light-excluded), to those of control clusters that were shaded naturally beneath the vine canopy (control-shaded). Treatment grape clusters were light-excluded during ripening by opaque white polypropylene enclosures; temperature, vapor pressure deficit, and light intensity were measured continually. All 15 'Merlot' grape anthocyanins accrued in both groups, indicating no accumulations were terminated from light-exclusion during ripening. Light-excluded clusters had an overall lower anthocyanin concentration (98.1 mg/100 g of berries) than that of control clusters (162.0 mg/100 g of berries), but it was not significantly different. Light-excluded clusters showed altered concentrations of nine individual anthocyanins that were significantly higher in control-shaded clusters. Although the changes in anthocyanin composition could not be attributed solely to the elimination of light, as there were also deviations in berry temperature and vapor pressure deficit concurrent with preventing light from reaching the treatment clusters.

  7. The MqsRA Toxin-Antitoxin System from Xylella fastidiosa Plays a Key Role in Bacterial Fitness, Pathogenicity, and Persister Cell Formation

    PubMed Central

    Merfa, Marcus V.; Niza, Bárbara; Takita, Marco A.; De Souza, Alessandra A.

    2016-01-01

    Through the formation of persister cells, bacteria exhibit tolerance to multidrug and other environmental stresses without undergoing genetic changes. The toxin-antitoxin (TA) systems are involved in the formation of persister cells because they are able to induce cell dormancy. Among the TA systems, the MqsRA system has been observed to be highly induced in persister cells of Xylella fastidiosa (causal agent of citrus variegated chlorosis—CVC) activated by copper stress, and has been described in Escherichia coli as related to the formation of persister cells and biofilms. Thus, we evaluated the role of this TA system in X. fastidiosa by overexpressing the MqsR toxin, and verified that the toxin positively regulated biofilm formation and negatively cell movement, resulting in reduced pathogenicity in citrus plants. The overexpression of MqsR also increased the formation of persister cells under copper stress. Analysis of the gene and protein expression showed that this system likely has an autoregulation mechanism to express the toxin and antitoxin in the most beneficial ratio for the cell to oppose stress. Our results suggest that this TA system plays a key role in the adaptation and survival of X. fastidiosa and reveal new insights into the physiology of phytopathogen-host interactions. PMID:27375608

  8. Ectopic expression of Xylella fastidiosa rpfF conferring production of diffusible signal factor in transgenic tobacco and citrus alters pathogen behavior and reduces disease severity.

    PubMed

    Caserta, Raquel; Souza-Neto, Reinaldo Rodrigues; Takita, Marco Aurelio; Lindow, Steven; Souza, Alessandra De

    2017-08-04

    The pathogenicity of Xylella fastidiosa is associated with its ability to colonize the xylem of host plants. Expression of genes contributing to xylem colonization are suppressed, while those necessary for insect vector acquisition are increased, with increasing concentrations of diffusible signal factor (DSF) whose production is dependent on RpfF. We previously demonstrated that transgenic citrus plants ectopically expressing rpfF from a citrus strain of X. fastidiosa subsp. pauca exhibited less susceptibility to Xanthomonas citri subsp. citri, another pathogen whose virulence is modulated by DSF accumulation. Here we demonstrate that ectopic expression of rpfF in both transgenic tobacco and sweet orange also confers a reduction in disease severity incited by X. fastidiosa and reduces its colonization of those plants. Decreased disease severity in the transgenic plants was generally associated with increased expression of genes conferring adhesiveness to the pathogen, and decreased expression of genes necessary for active motility, accounting for the reduced population sizes achieved in the plants, apparently by limiting pathogen dispersal through the plant. Plant-derived DSF signal molecules in a host plant therefore can be exploited to interfere with more than one pathogen whose virulence is controlled by DSF signaling.

  9. Global expression profile of biofilm resistance to antimicrobial compounds in the plant-pathogenic bacterium Xylella fastidiosa reveals evidence of persister cells.

    PubMed

    Muranaka, Lígia S; Takita, Marco A; Olivato, Jacqueline C; Kishi, Luciano T; de Souza, Alessandra A

    2012-09-01

    Investigations of biofilm resistance response rarely focus on plant-pathogenic bacteria. Since Xylella fastidiosa is a multihost plant-pathogenic bacterium that forms biofilm in the xylem, the behavior of its biofilm in response to antimicrobial compounds needs to be better investigated. We analyzed here the transcriptional profile of X. fastidiosa subsp. pauca in response to inhibitory and subinhibitory concentrations of copper and tetracycline. Copper-based products are routinely used to control citrus diseases in the field, while antibiotics are more widely used for bacterial control in mammals. The use of antimicrobial compounds triggers specific responses to each compound, such as biofilm formation and phage activity for copper. Common changes in expression responses comprise the repression of genes associated with metabolic functions and movement and the induction of toxin-antitoxin systems, which have been associated with the formation of persister cells. Our results also show that these cells were found in the population at a ca. 0.05% density under inhibitory conditions for both antimicrobial compounds and that pretreatment with subinhibitory concentration of copper increases this number. No previous report has detected the presence of these cells in X. fastidiosa population, suggesting that this could lead to a multidrug tolerance response in the biofilm under a stressed environment. This is a mechanism that has recently become the focus of studies on resistance of human-pathogenic bacteria to antibiotics and, based on our data, it seems to be more broadly applicable.

  10. Characterization of the TolB-Pal trans-envelope complex from Xylella fastidiosa reveals a dynamic and coordinated protein expression profile during the biofilm development process.

    PubMed

    Santos, Clelton A; Janissen, Richard; Toledo, Marcelo A S; Beloti, Lilian L; Azzoni, Adriano R; Cotta, Monica A; Souza, Anete P

    2015-10-01

    The intriguing roles of the bacterial Tol-Pal trans-envelope protein complex range from maintenance of cell envelope integrity to potential participation in the process of cell division. In this study, we report the characterization of the XfTolB and XfPal proteins of the Tol-Pal complex of Xylella fastidiosa. X. fastidiosa is a major plant pathogen that forms biofilms inside xylem vessels, triggering the development of diseases in important cultivable plants around the word. Based on functional complementation experiments in Escherichia coli tolB and pal mutant strains, we confirmed the role of xftolB and xfpal in outer membrane integrity. In addition, we observed a dynamic and coordinated protein expression profile during the X. fastidiosa biofilm development process. Using small-angle X-ray scattering (SAXS), the low-resolution structure of the isolated XfTolB-XfPal complex in solution was solved for the first time. Finally, the localization of the XfTolB and XfPal polar ends was visualized via immunofluorescence labeling in vivo during bacterial cell growth. Our results highlight the major role of the components of the cell envelope, particularly the TolB-Pal complex, during the different phases of bacterial biofilm development.

  11. Identification of a response regulator involved in surface attachment, cell-cell aggregation, exopolysaccharide production and virulence in the plant pathogen Xylella fastidiosa.

    PubMed

    Voegel, Tanja M; Doddapaneni, Harshavardhan; Cheng, Davis W; Lin, Hong; Stenger, Drake C; Kirkpatrick, Bruce C; Roper, M Caroline

    2013-04-01

    Xylella fastidiosa, the causal agent of Pierce's disease of grapevine, possesses several two-component signal transduction systems that allow the bacterium to sense and respond to changes in its environment. Signals are perceived by sensor kinases that autophosphorylate and transfer the phosphate to response regulators (RRs), which direct an output response, usually by acting as transcriptional regulators. In the X. fastidiosa genome, 19 RRs were found. A site-directed knockout mutant in one unusual RR, designated XhpT, composed of a receiver domain and a histidine phosphotransferase output domain, was constructed. The resulting mutant strain was analysed for changes in phenotypic traits related to biofilm formation and gene expression using microarray analysis. We found that the xhpT mutant was altered in surface attachment, cell-cell aggregation, exopolysaccharide (EPS) production and virulence in grapevine. In addition, this mutant had an altered transcriptional profile when compared with wild-type X. fastidiosa in genes for several biofilm-related traits, such as EPS production and haemagglutinin adhesins.

  12. The development of global GRAPES 4DVAR

    NASA Astrophysics Data System (ADS)

    Liu, Yongzhu

    2017-04-01

    Four-dimensional variation data assimilation (4DVAR) has given a great contribution to the improvement of NWP system over the past twenty years. Therefore, our strategy is to develop an operational global 4D-Var system from the outset. The aim at the paper is to introduce the development of the global GRAPES four-dimensional variation data assimilation (4DVAR) using incremental analysis schemes and to presents results of a comparison between 4DVAR using 6-hour assimilation window and simplified physics during the minimization with three-dimensional variation data assimilation (3DVAR). The dynamical cores of the tangent-linear and adjoint models are developed directly based on the non-hydrostatic forecast model. In addition, the standard correctness checks have been performed. As well as the development adjoint codes, most of our work is focused on improving the computational efficiency since the bulk of the computational cost of 4D-Var is in the integration of the tangent-linear and adjoint models. In terms of tangent-linear model, the wall-clock time is reduced to about 1.2 times as much as one of nonlinear model through the optimizing of the software framework. The significant computational cost savings on adjoint model result from the removing the redundant recompilations of model trajectories. It is encouraging that the wall-clock time of adjoint model is less than 1.5 times as much as one of nonlinear model. The current difficulty is that the numerical scheme used within the linear model is based on strategically on the numeric of the corresponding nonlinear model. Further computational acceleration should be expected from the improvement on nonlinear numerical algorithm. A series of linearized physical parameterization schemes has been developed to improve the representation of perturbed fields in the linear model. It consists of horizontal and vertical diffusion, sub-grid scale orographic gravity wave drag, large-scale condensation and cumulus convection

  13. Characterization of the Xylella fastidiosa PD1671 Gene Encoding Degenerate c-di-GMP GGDEF/EAL Domains, and Its Role in the Development of Pierce’s Disease

    PubMed Central

    Cursino, Luciana; Athinuwat, Dusit; Patel, Kelly R.; Galvani, Cheryl D.; Zaini, Paulo A.; Li, Yaxin; De La Fuente, Leonardo; Hoch, Harvey C.; Burr, Thomas J.; Mowery, Patricia

    2015-01-01

    Xylella fastidiosa is an important phytopathogenic bacterium that causes many serious plant diseases including Pierce’s disease of grapevines. X. fastidiosa is thought to induce disease by colonizing and clogging xylem vessels through the formation of cell aggregates and bacterial biofilms. Here we examine the role in X. fastidiosa virulence of an uncharacterized gene, PD1671, annotated as a two-component response regulator with potential GGDEF and EAL domains. GGDEF domains are found in c-di-GMP diguanylate cyclases while EAL domains are found in phosphodiesterases, and these domains are for c-di-GMP production and turnover, respectively. Functional analysis of the PD1671 gene revealed that it affected multiple X. fastidiosa virulence-related phenotypes. A Tn5 PD1671 mutant had a hypervirulent phenotype in grapevines presumably due to enhanced expression of gum genes leading to increased exopolysaccharide levels that resulted in elevated biofilm formation. Interestingly, the PD1671 mutant also had decreased motility in vitro but did not show a reduced distribution in grapevines following inoculation. Given these responses, the putative PD1671 protein may be a negative regulator of X. fastidiosa virulence. PMID:25811864

  14. Analysis of the grape (Vitis vinifera L.) thaumatin-like protein (TLP) gene family and demonstration that TLP29 contributes to disease resistance.

    PubMed

    Yan, Xiaoxiao; Qiao, Hengbo; Zhang, Xiuming; Guo, Chunlei; Wang, Mengnan; Wang, Yuejin; Wang, Xiping

    2017-06-27

    Thaumatin-like protein (TLP) is present as a large family in plants, and individual members play different roles in various responses to biotic and abiotic stresses. Here we studied the role of 33 putative grape (Vitis vinifera L.) TLP genes (VvTLP) in grape disease resistance. Heat maps analysis compared the expression profiles of 33 genes in disease resistant and susceptible grape species infected with anthracnose (Elsinoe ampelina), powdery mildew (Erysiphe necator) or Botrytis cinerea. Among these 33 genes, the expression level of TLP29 increased following the three pathogens inoculations, and its homolog from the disease resistant Chinese wild grape V. quinquangularis cv. 'Shang-24', was focused for functional studies. Over-expression of TLP29 from grape 'Shang-24' (VqTLP29) in Arabidopsis thaliana enhanced its resistance to powdery mildew and the bacterium Pseudomonas syringae pv. tomato DC3000, but decreased resistance to B. cinerea. Moreover, the stomatal closure immunity response to pathogen associated molecular patterns was strengthened in the transgenic lines. A comparison of the expression profiles of various resistance-related genes after infection with different pathogens indicated that VqTLP29 may be involved in the salicylic acid and jasmonic acid/ethylene signaling pathways.

  15. Occurrence of ochratoxin A producing fungi in wine and table grapes in Israel.

    PubMed

    Guzev, L; Danshin, A; Ziv, S; Lichter, A

    2006-09-01

    A 3-year survey was conducted to assay the number of Aspergillus Section Nigri isolates and in vitro ochratoxin A (OTA) production capacity in 10 vineyards in Israel. The survey included field sampling of two wine cultivars, 'Sauvignon Blanc' and 'Cabernet Sauvignon' as well as the table grape cultivar 'Superior'. A total of 2114 isolates were analyzed and of those 161 isolates were shown to produce OTA. The major finding was that Aspergillus carbonarius (336 tested strains) is the most consistent producer of OTA, with approximately 35% of the isolates identified as positive in vitro. In comparison, 3.1% of other isolates from the Aspergillus niger aggregate (of 1432 strains) produced OTA in vitro. In contrast, none of the 346 tested strains with a uniseriate head morphology produced OTA. The incidence of infected berries was very low before veraison, while at harvest, this frequency was twice as high. In general, the composition of black Aspergilli did not differ during berry development. Generally, more OTA-producing isolates were isolated from the surface of table grapes cv. 'Superior' compared to 'Sauvignon Blanc'. None of the samples collected at harvest contained traces of OTA in the juice. This study shows that grapes in Israel are contaminated with ochratoxigenic species which represent a risk of OTA contamination.

  16. Infection

    MedlinePlus

    ... or articles contaminated by them is an important component of infection control and isolation precautions. To help protect exposure to infectious materials, wash your hands: Wear gloves: In addition to ...

  17. Reduced-molecular-weight derivatives of frost grape polysaccharide

    USDA-ARS?s Scientific Manuscript database

    A new Type II arabinogalactan was recently described as an abundant gum exudate from stems of wild frost grape (Vitus riparia Michx.). Native frost grape polysaccharide (FGP), with an estimated molecular weight of 1.6 ± 0.1 x 107 Da, was progressively and irreversibly modified by heat treatment to r...

  18. SNP Validation and Genetic Diversity in Cultivated Tomatoes and Grapes

    USDA-ARS?s Scientific Manuscript database

    Cultivated grapes and tomatoes have very different reproductive systems. While grapes are often outcrossed and grafted, tomatoes are generally selfed and propogated by seed. Large-scale public EST datasets were used in both crops to predict SNPs and PCR primers flanking these SNPs. Genomic DNA was a...

  19. Genetic structure and domestication history of the grape

    USDA-ARS?s Scientific Manuscript database

    The grape is one of the earliest domesticated fruit crops and, since antiquity, it has been widely cultivated and prized for its fruit and wine. We characterized genome-wide patterns of genetic variation in over 1000 samples of the domesticated grape, Vitis vinifera, and its wild relative, Vitis sy...

  20. The USDA/ARS Grape Breeding Program at Parlier, CA

    USDA-ARS?s Scientific Manuscript database

    The California table grape industry needs a series of seedless table grapes that ripen from early to late, having high quality red, black or white fruit that store and ship well. The raisin industry needs new seedless cultivars adapted to mechanical harvest without supplemental drying. Buyers and ...

  1. Child Deaths Highlight Choking Dangers Posed by Grapes

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_162679.html Child Deaths Highlight Choking Dangers Posed by Grapes Deaths of 5-year-old and toddler cited in ... 2016 (HealthDay News) -- Young children can choke to death on whole grapes, warn the authors of a ...

  2. Performance of Muscadine Grape Cultivars in South Mississippi

    USDA-ARS?s Scientific Manuscript database

    Muscadines are grapes are indigenous to the Southeastern United States and are highly prized for their unique flavor for both fresh market fruit and for processing for juice, jelly, and wine. Skin color varies among muscadine grape cultivars from bronze to purple and berry also quality varies, maki...

  3. Association between Grape Yeast Communities and the Vineyard Ecosystems

    PubMed Central

    Drumonde-Neves, João; Lima, Teresa; Schuller, Dorit; Pais, Célia

    2017-01-01

    The grape yeast biota from several wine-producing areas, with distinct soil types and grapevine training systems, was assessed on five islands of Azores Archipelago, and differences in yeast communities composition associated with the geographic origin of the grapes were explored. Fifty-seven grape samples belonging to the Vitis vinifera grapevine cultivars Verdelho dos Açores (Verdelho), Arinto da Terceira (Arinto) and Terrantez do Pico (Terrantez) were collected in two consecutive years and 40 spontaneous fermentations were achieved. A total of 1710 yeast isolates were obtained from freshly crushed grapes and 1200 from final stage of fermentations. Twenty-eight species were identified, Hanseniaspura uvarum, Pichia terricola and Metschnikowia pulcherrima being the three most representative species isolated. Candida carpophila was encountered for the first time as an inhabitant of grape or wine-associated environments. In both sampling years, a higher proportion of H. uvarum in fresh grapes from Verdelho cultivar was observed, in comparison with Arinto cultivar. Qualitatively significant differences were found among yeast communities from several locations on five islands of the Archipelago, particularly in locations with distinctive agro-ecological compositions. Our results are in agreement with the statement that grape-associated microbial biogeography is non-randomly associated with interactions of climate, soil, cultivar, and vine training systems in vineyard ecosystems. Our observations strongly support a possible linkage between grape yeast and wine typicality, reinforcing the statement that different viticultural terroirs harbor distinctive yeast biota, in particular in vineyards with very distinctive environmental conditions. PMID:28085916

  4. QTL analysis of fruit quality traits in muscadine grapes

    USDA-ARS?s Scientific Manuscript database

    Muscadine grapes (Vitis rotundifolia) are an important native fruit crop grown in the southeastern United States. To facilitate the breeding of improved cultivars of muscadine grapes a quantitative trait loci (QTL) analysis was conducted on several flower and fruit characteristics of two segregatin...

  5. Genetic structure and domestication history of the grape

    USDA-ARS?s Scientific Manuscript database

    The grape is one of the earliest domesticated fruit crops and, since antiquity, it has been widely cultivated and prized for its fruit and wine. Here, we characterize genome-wide patterns of genetic variation in over 1,000 samples of the domesticated grape, Vitis vinifera subsp. vinifera, and its wi...

  6. Association between Grape Yeast Communities and the Vineyard Ecosystems.

    PubMed

    Drumonde-Neves, João; Franco-Duarte, Ricardo; Lima, Teresa; Schuller, Dorit; Pais, Célia

    2017-01-01

    The grape yeast biota from several wine-producing areas, with distinct soil types and grapevine training systems, was assessed on five islands of Azores Archipelago, and differences in yeast communities composition associated with the geographic origin of the grapes were explored. Fifty-seven grape samples belonging to the Vitis vinifera grapevine cultivars Verdelho dos Açores (Verdelho), Arinto da Terceira (Arinto) and Terrantez do Pico (Terrantez) were collected in two consecutive years and 40 spontaneous fermentations were achieved. A total of 1710 yeast isolates were obtained from freshly crushed grapes and 1200 from final stage of fermentations. Twenty-eight species were identified, Hanseniaspura uvarum, Pichia terricola and Metschnikowia pulcherrima being the three most representative species isolated. Candida carpophila was encountered for the first time as an inhabitant of grape or wine-associated environments. In both sampling years, a higher proportion of H. uvarum in fresh grapes from Verdelho cultivar was observed, in comparison with Arinto cultivar. Qualitatively significant differences were found among yeast communities from several locations on five islands of the Archipelago, particularly in locations with distinctive agro-ecological compositions. Our results are in agreement with the statement that grape-associated microbial biogeography is non-randomly associated with interactions of climate, soil, cultivar, and vine training systems in vineyard ecosystems. Our observations strongly support a possible linkage between grape yeast and wine typicality, reinforcing the statement that different viticultural terroirs harbor distinctive yeast biota, in particular in vineyards with very distinctive environmental conditions.

  7. 7 CFR 457.149 - Table grape crop insurance provisions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... optional unit is located on non-contiguous land or grown and insured under an organic farming practice. (b... optional unit: (1) Is located on non-contiguous land; or (2) Consists of a separate type when separate... marketable grapes are carried out. Type. A category of grapes (one or more varieties) identified as a type...

  8. 7 CFR 457.149 - Table grape crop insurance provisions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... established if each optional unit is located on non-contiguous land or grown and insured under an organic... if each optional unit: (1) Is located on non-contiguous land; or (2) Consists of a separate type when... to produce fresh marketable grapes are carried out. Type. A category of grapes (one or more...

  9. 7 CFR 457.149 - Table grape crop insurance provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... established if each optional unit is located on non-contiguous land or grown and insured under an organic... if each optional unit: (1) Is located on non-contiguous land; or (2) Consists of a separate type when... to produce fresh marketable grapes are carried out. Type. A category of grapes (one or more...

  10. 7 CFR 457.149 - Table grape crop insurance provisions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... optional unit is located on non-contiguous land or grown and insured under an organic farming practice. (b... optional unit: (1) Is located on non-contiguous land; or (2) Consists of a separate type when separate... marketable grapes are carried out. Type. A category of grapes (one or more varieties) identified as a type...

  11. 7 CFR 457.149 - Table grape crop insurance provisions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... optional unit is located on non-contiguous land or grown and insured under an organic farming practice. (b... optional unit: (1) Is located on non-contiguous land; or (2) Consists of a separate type when separate... marketable grapes are carried out. Type. A category of grapes (one or more varieties) identified as a type...

  12. Phenolic Content of Raisin Grape Varieties and Genotypes

    USDA-ARS?s Scientific Manuscript database

    Six raisin grape cultivars and ten new raisin grape selections were analyzed for antioxidant activity (ABTS assay) and for total and individual phenolic compounds. Samples were freeze-dried and values are reported on a dry weight basis. Antioxidant activity across the 16 samples ranged from 7.7 to...

  13. 75 FR 17031 - Grapes Grown in a Designated Area of Southeastern California and Imported Table Grapes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-05

    ... handling of any grade, size, quality, maturity, or pack of any and all varieties of grapes during the... individual consumer packages known as clamshells. These containers have been most commonly used to pack strawberries in the past but are also being used for other fruit. They are made of a clear, rigid plastic and...

  14. Antioxidant effects of grape vine cane extracts from different Chinese grape varieties on edible oils.

    PubMed

    Min, Zhuo; Guo, Zemei; Wang, Kai; Zhang, Ang; Li, Hua; Fang, Yulin

    2014-09-23

    This study involved the determination of the peroxide value (POV) as a measure of the resistance of the oxidation of edible oil with grape vine cane additives to assess their antioxidation potential. The study demonstrated that grape extracts of canes could effectively inhibit the lipid oxidation of edible oils and that this ability varied significantly due to the different extraction solvents employed, as well as to the different varieties of canes used. Lipid oxidation of edible oils was significantly reduced under an accelerated storage condition of 70 ± 1 °C in the presence of Vitamin C (VC), which was chosen as a synergist of grape vine cane extract. A 4:1 ratio of Victoria Blanc-ethyl acetate fraction (EAF) and VC led to a significant lowering of the peroxide value and indicated a better antioxidant effect. Thus, these results indicated that some varieties of grape vine cane extracts could be applied as natural antioxidants for elevation of the quality of edible oils in the food industry.

  15. Comparing Wild American Grapes with Vitis vinifera: A Metabolomics Study of Grape Composition.

    PubMed

    Narduzzi, Luca; Stanstrup, Jan; Mattivi, Fulvio

    2015-08-05

    We analyzed via untargeted UHPLC-ESI-Q-TOF-MS the metabolome of the berry tissues (skin, pulp, seeds) of some American Vitis species (Vitis cinerea, Vitis californica, Vitis arizonica), together with four interspecific hybrids, and seven Vitis vinifera cultivars, aiming to find differences in the metabolomes of the American Vitis sp. versus Vitis vinifera. Apart from the known differences, that is, more complex content of anthocyanins and stilbenoids in the American grapes, we observed higher procyanidin accumulation (tens to hundreds of times) in the vinifera skin and seeds in comparison to American berries, and we confirmed this result via phloroglucinolysis. In the American grapes considered, we did not detect the accumulation of pleasing aroma precursors (terpenoids, glycosides), whereas they are common in vinifera grapes. We also found accumulation of hydrolyzable tannins and their precursors in the skin of the wild American grapes, which has never been reported earlier in any of the species under investigation. Such information is needed to improve the design of new breeding programs, lowering the risk of retaining undesirable characteristics in the chemical phenotype of the offspring.

  16. Super-parameterization in GRAPES: The construction of SP-GRAPES and associated preliminary results

    NASA Astrophysics Data System (ADS)

    Zhu, Feng; Xu, Guoqiang; Zheng, Xiaohui; Wang, Yuhong

    2015-04-01

    Super-parameterization (SP) aims to explicitly represent deep convection within a coarse resolution global model by embedding a cloud resolving model (CRM) in each column of the mother model. For the first time, we implemented the SP in a mesoscale regional weather model, the Global/Regional Assimilation and PrEdiction System (GRAPES). The constructed SP-GRAPES uses a two-dimensional (2D) CRM in each grid column. A control and two SP simulations are conducted for the Beijing "7.21" heavy rainfall event to evaluate improvements in GRAPES using SP. The SP-run-I is a basic SP run delivering microphysics feedback only, whereas the SP-run-II delivers both microphysical and cloud fraction feedbacks. A comparison of the runs indicates that the SP-run-I has a slightly positive impact on the precipitation forecast than the control run. However, the inclusion of cloud fraction feedback leads to an evident overall improvement, particularly in terms of cloud fraction and 24-h cumulative precipitation. Although this is only a preliminary study using SP-GRAPES, we believe that it will provide considerable guidance for follow-up studies using SP in China.

  17. Polymorphism and phylogenetic species delimitation in filamentous fungi from predominant mycobiota in withered grapes.

    PubMed

    Lorenzini, M; Cappello, M S; Logrieco, A; Zapparoli, G

    2016-12-05

    Filamentous fungi are the main pathogens of withered grapes destined for passito wine production. Knowledge of which species inhabit these post-harvest fruits and their pathogenicity is essential in order to develop strategies to control infection, but is still scarce. This study investigated the predominant mycobiota of withered grapes through a cultivation-dependent approach. Strain and species heterogeneity was evidenced on examining isolates collected over three consecutive years. Colony morphology and PCR-restriction fragment length polymorphism (PCR-RFLP) analysis revealed the occurrence of several phenotypes and haplotypes, respectively. Strains were phylogenetically analyzed based on sequence typing of different genes or regions (e.g. calmodulin, β-tubulin and internal transcribed spacer region). Beside the most common necrotrophic-saprophytic species of Penicillium, Aspergillus, Alternaria and Botrytis species responsible for fruit rot, other saprobic species were identified (e.g. Trichoderma atroviride, Sarocladium terricola, Arthrinium arundinis and Diaporthe eres) generally not associated with post-harvest fruit diseases. Species such as Penicillium ubiquetum, Cladosporium pseudocladosporioides, Lichtheimia ramosa, Sarocladium terricola, Diaporthe nobilis, Bipolaris secalis, Paraconiothyrium fuckelii and Galactomyces reessii that had never previously been isolated from grapevine or grape were also identified. Moreover, it was not possible to assign a species to some isolates, while some members of Didymosphaeriaceae and Didymellaceae remained unclassified even at genus level. This study provides insights into the diversity of the epiphytic fungi inhabiting withered grapes and evidences the importance of their identification to understand the causes of fruit diseases. Finally, phylogenetic species delimitation furnished data of interest to fungal taxonomy. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Grape marc extract acts as elicitor of plant defence responses.

    PubMed

    Goupil, Pascale; Benouaret, Razik; Charrier, Olivia; Ter Halle, Alexandra; Richard, Claire; Eyheraguibel, Boris; Thiery, Denis; Ledoigt, Gérard

    2012-07-01

    Plant protection based on novel alternative strategies is a major concern in agriculture to sustain pest management. The marc extract of red grape cultivars reveals plant defence inducer properties. Treatment with grape marc extract efficiently induced hypersensitive reaction-like lesions with cell death evidenced by Evans Blue staining of tobacco leaves. Examination of the infiltration zone and the surrounding areas under UV light revealed the accumulation of autofluorescent compounds. Both leaf infiltration and a foliar spray of the red grape extract on tobacco leaves induced defence gene expression. The PR1 and PR2 target genes were upregulated locally and systemically in tobacco plants following grape marc extract treatment. The grape extract elicited an array of plant defence responses making this natural compound a potential phytosanitary product with a challenging issue and a rather attractive option for sustainable agriculture and environmentally friendly practices.

  19. 7 CFR 319.56-37 - Grapes from the Republic of Korea.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Grapes from the Republic of Korea. 319.56-37 Section... Grapes from the Republic of Korea. Grapes (Vitis spp.) may be imported into the United States from the... provisions of this subpart: (a) The fields where the grapes are grown must be inspected during the growing...

  20. 7 CFR 319.56-37 - Grapes from the Republic of Korea.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Grapes from the Republic of Korea. 319.56-37 Section... Grapes from the Republic of Korea. Grapes (Vitis spp.) may be imported into the United States from the... provisions of this subpart: (a) The fields where the grapes are grown must be inspected during the growing...