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Sample records for citri subsp citri

  1. Xanthomonas citri subsp. citri type IV Pilus is required for twitching motility, biofilm development, and adherence.

    Science.gov (United States)

    Dunger, German; Guzzo, Cristiane R; Andrade, Maxuel O; Jones, Jeffrey B; Farah, Chuck S

    2014-10-01

    Bacterial type IV pili (T4P) are long, flexible surface filaments that consist of helical polymers of mostly pilin subunits. Cycles of polymerization, attachment, and depolymerization mediate several pilus-dependent bacterial behaviors, including twitching motility, surface adhesion, pathogenicity, natural transformation, escape from immune system defense mechanisms, and biofilm formation. The Xanthomonas citri subsp. citri strain 306 genome codes for a large set of genes involved in T4P biogenesis and regulation and includes several pilin homologs. We show that X. citri subsp. citri can exhibit twitching motility in a manner similar to that observed in other bacteria such as Pseudomonas aeruginosa and Xylella fastidiosa and that this motility is abolished in Xanthomonas citri subsp. citri knockout strains in the genes coding for the major pilin subunit PilAXAC3241, the ATPases PilBXAC3239 and PilTXAC2924, and the T4P biogenesis regulators PilZXAC1133 and FimXXAC2398. Microscopy analyses were performed to compare patterns of bacterial migration in the wild-type and knockout strains and we observed that the formation of mushroom-like structures in X. citri subsp. citri biofilm requires a functional T4P. Finally, infection of X. citri subsp. citri cells by the bacteriophage (ΦXacm4-11 is T4P dependent. The results of this study improve our understanding of how T4P influence Xanthomonas motility, biofilm formation, and susceptibility to phage infection. PMID:25180689

  2. Foliar application of biofilm formation-inhibiting compounds enhances control of citrus canker caused by Xanthomonas citri subsp. citri.

    Science.gov (United States)

    Li, Jinyun; Wang, Nian

    2014-02-01

    Citrus canker caused by the bacterium Xanthomonas citri subsp. citri is an economically important disease of citrus worldwide. Biofilm formation plays an important role in early infection of X. citri subsp. citri on host leaves. In this study, we assessed the hypothesis that small molecules inhibiting biofilm formation reduce X. citri subsp. citri infection and enhance the control of citrus canker disease. D-leucine and 3-indolylacetonitrile (IAN) were found to prevent biofilm formation by X. citri subsp. citri on different abiotic surfaces and host leaves at a concentration lower than the minimum inhibitory concentration (MIC). Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis indicated that IAN repressed expression of chemotaxis/motility-related genes in X. citri subsp. citri. In laboratory experiments, planktonic and biofilm cells of X. citri subsp. citri treated with D-leucine and IAN, either alone or in combination, were more susceptible to copper (CuSO4) than those untreated. In greenhouse assays, D-leucine and IAN applied alone or combined with copper reduced both the number of canker lesions and bacterial populations of X. citri subsp. citri on citrus host leaves. This study provides the basis for the use of foliar-applied biofilm inhibitors for the control of citrus canker alone or combined with copper-based bactericides. PMID:23901828

  3. Foliar application of biofilm formation-inhibiting compounds enhances control of citrus canker caused by Xanthomonas citri subsp. citri.

    Science.gov (United States)

    Li, Jinyun; Wang, Nian

    2014-02-01

    Citrus canker caused by the bacterium Xanthomonas citri subsp. citri is an economically important disease of citrus worldwide. Biofilm formation plays an important role in early infection of X. citri subsp. citri on host leaves. In this study, we assessed the hypothesis that small molecules inhibiting biofilm formation reduce X. citri subsp. citri infection and enhance the control of citrus canker disease. D-leucine and 3-indolylacetonitrile (IAN) were found to prevent biofilm formation by X. citri subsp. citri on different abiotic surfaces and host leaves at a concentration lower than the minimum inhibitory concentration (MIC). Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis indicated that IAN repressed expression of chemotaxis/motility-related genes in X. citri subsp. citri. In laboratory experiments, planktonic and biofilm cells of X. citri subsp. citri treated with D-leucine and IAN, either alone or in combination, were more susceptible to copper (CuSO4) than those untreated. In greenhouse assays, D-leucine and IAN applied alone or combined with copper reduced both the number of canker lesions and bacterial populations of X. citri subsp. citri on citrus host leaves. This study provides the basis for the use of foliar-applied biofilm inhibitors for the control of citrus canker alone or combined with copper-based bactericides.

  4. Fortunella margarita Transcriptional Reprogramming Triggered by Xanthomonas citri subsp. citri

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    Khalaf Abeer A

    2011-11-01

    Full Text Available Abstract Background Citrus canker disease caused by the bacterial pathogen Xanthomonas citri subsp. citri (Xcc has become endemic in areas where high temperature, rain, humidity, and windy conditions provide a favourable environment for the dissemination of the bacterium. Xcc is pathogenic on many commercial citrus varieties but appears to elicit an incompatible reaction on the citrus relative Fortunella margarita Swing (kumquat, in the form of a very distinct delayed necrotic response. We have developed subtractive libraries enriched in sequences expressed in kumquat leaves during both early and late stages of the disease. The isolated differentially expressed transcripts were subsequently sequenced. Our results demonstrate how the use of microarray expression profiling can help assign roles to previously uncharacterized genes and elucidate plant pathogenesis-response related mechanisms. This can be considered to be a case study in a citrus relative where high throughput technologies were utilized to understand defence mechanisms in Fortunella and citrus at the molecular level. Results cDNAs from sequenced kumquat libraries (ESTs made from subtracted RNA populations, healthy vs. infected, were used to make this microarray. Of 2054 selected genes on a customized array, 317 were differentially expressed (P Conclusion Functional categorization of kumquat Xcc-responsive genes revealed an enhanced defence-related metabolism as well as a number of resistant response-specific genes in the kumquat transcriptome in response to Xcc inoculation. Gene expression profile(s were analyzed to assemble a comprehensive and inclusive image of the molecular interaction in the kumquat/Xcc system. This was done in order to elucidate molecular mechanisms associated with the development of the hypersensitive response phenotype in kumquat leaves. These data will be used to perform comparisons among citrus species to evaluate means to enhance the host immune responses

  5. Complete Genome Sequence of Xanthomonas citri subsp. citri Strain Aw12879, a Restricted-Host-Range Citrus Canker-Causing Bacterium

    OpenAIRE

    Jalan, Neha; Kumar, Dibyendu; Yu, Fahong; Jones, Jeffrey B; Graham, James H; Wang, Nian

    2013-01-01

    Xanthomonas citri subsp. citri causes citrus canker. The Asiatic strain has a broad host range, whereas the Wellington variant has a restricted host range. Here, we present the complete genome of X. citri subsp. citri strain AW12879. This study lays the foundation to further characterize the mechanisms for virulence and host range of X. citri.

  6. Identification of an Extracellular Endoglucanase That Is Required for Full Virulence in Xanthomonas citri subsp. citri.

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    Tian Xia

    Full Text Available Xanthomonas citri subsp. citri causes citrus canker disease, which is characterized by the formation of water-soaked lesions, white or yellow spongy pustules and brown corky canker. In this work, we report the contribution of extracellular endoglucanase to canker development during infection. The ectopic expression of nine putative cellulases in Escherichia coli indicated that two endoglucanases, BglC3 and EngXCA, show carboxymethyl cellulase activity. Both bglC3 and engXCA genes were transcribed in X. citri subsp. citri, however, only BglC3 protein was detected outside the cell in western blot analysis. The deletion of bglC3 gene resulted in complete loss of extracellular carboxymethyl cellulase activity and delayed the onset of canker symptoms in both infiltration- and wound-inoculation assays. When growing in plant tissue, the cell density of bglC3 mutant was lower than that of the wild type. Our data demonstrated that BglC3 is an extracellular endoglucanase required for the full virulence of X. citri subsp. citri.

  7. The type III protein secretion system contributes to Xanthomonas citri subsp. citri biofilm formation

    KAUST Repository

    Zimaro, Tamara

    2014-04-18

    Background: Several bacterial plant pathogens colonize their hosts through the secretion of effector proteins by a Type III protein secretion system (T3SS). The role of T3SS in bacterial pathogenesis is well established but whether this system is involved in multicellular processes, such as bacterial biofilm formation has not been elucidated. Here, the phytopathogen Xanthomonas citri subsp. citri (X. citri) was used as a model to gain further insights about the role of the T3SS in biofilm formation. Results: The capacity of biofilm formation of different X. citri T3SS mutants was compared to the wild type strain and it was observed that this secretion system was necessary for this process. Moreover, the T3SS mutants adhered proficiently to leaf surfaces but were impaired in leaf-associated growth. A proteomic study of biofilm cells showed that the lack of the T3SS causes changes in the expression of proteins involved in metabolic processes, energy generation, exopolysaccharide (EPS) production and bacterial motility as well as outer membrane proteins. Furthermore, EPS production and bacterial motility were also altered in the T3SS mutants. Conclusions: Our results indicate a novel role for T3SS in X. citri in the modulation of biofilm formation. Since this process increases X. citri virulence, this study reveals new functions of T3SS in pathogenesis. 2014 Zimaro et al.; licensee BioMed Central Ltd.

  8. Characterization of a variant of Xanthomonas citri subsp. citri that triggers a host-specific defense response.

    Science.gov (United States)

    Chiesa, María A; Siciliano, María F; Ornella, Leonardo; Roeschlin, Roxana A; Favaro, María A; Delgado, Natalia Pino; Sendín, Lorena N; Orce, Ingrid G; Ploper, L Daniel; Vojnov, Adrian A; Vacas, José Gadea; Filippone, María P; Castagnaro, Atilio P; Marano, María R

    2013-06-01

    Citrus is an economically important fruit crop that is severely afflicted by Asiatic citrus bacterial canker (CBC), a disease caused by the phytopathogen Xanthomonas citri subsp. citri (X. citri). To gain insight into the molecular epidemiology of CBC, 42 Xanthomonas isolates were collected from a range of Citrus spp. across 17 different orchards in Tucumán, Argentina and subjected to molecular, biochemical, and pathogenicity tests. Analysis of genome-specific X. citri markers and DNA polymorphisms based on repetitive elements-based polymerase chain reaction showed that all 42 isolates belonged to X. citri. Interestingly, pathogenicity tests showed that one isolate, which shares >90% genetic similarity to the reference strain X. citri T, has host range specificity. This new variant of X. citri subsp. citri, named X. citri A(T), which is deficient in xanthan production, induces an atypical, noncankerous chlorotic phenotype in Citrus limon and C. paradisi and weak cankerous lesions in C. aurantifolia and C. clementina leaves. In C. limon, suppression of canker development is concomitant with an oxidative burst; xanthan is not implicated in the phenotype induced by this interaction, suggesting that other bacterial factors would be involved in triggering the defense response.

  9. Expression of Xylella fastidiosa RpfF in citrus disrupts signaling in Xanthomonas citri subsp. citri and thereby its virulence.

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    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. PMID:25099341

  10. Identification of seven novel virulence genes from Xanthomonas citri subsp. citri by Tn5-based random mutagenesis.

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    Song, Xue; Guo, Jing; Ma, Wen-xiu; Ji, Zhi-yuan; Zou, Li-fang; Chen, Gong-you; Zou, Hua-song

    2015-05-01

    To identify novel virulence genes, a mutant library of Xanthomonas citri subsp. citri 29-1 was produced using EZ-Tn5 transposon and the mutants were inoculated into susceptible grapefruit. Forty mutants with altered virulence phenotypes were identified. Nine of the mutants showed a complete loss of citrus canker induction, and the other 31 mutants resulted in attenuated canker symptoms. Southern blot analysis revealed that each of the mutants carried a single copy of Tn5. The flanking sequence was identified by plasmid rescue and 18 different ORFs were identified in the genome sequence. Of these 18 ORFs, seven had not been previously associated with the virulence of X. citri subsp. citri and were therefore confirmed by complementation analysis. Real-time PCR analysis showed that the seven genes were upregulated when the bacteria were grown in citrus plants, suggesting that the expression of these genes was essential for canker development. PMID:25935304

  11. Different Transcriptional Response to Xanthomonas citri subsp. citri between Kumquat and Sweet Orange with Contrasting Canker Tolerance

    OpenAIRE

    Xing-Zheng Fu; Xiao-Qing Gong; Yue-Xin Zhang; Yin Wang; Ji-Hong Liu

    2012-01-01

    Citrus canker disease caused by Xanthomonas citri subsp. citri (Xcc) is one of the most devastating biotic stresses affecting the citrus industry. Meiwa kumquat (Fortunella crassifolia) is canker-resistant, while Newhall navel orange (Citrus sinensis Osbeck) is canker-sensitive. To understand the molecular mechanisms underlying the differences in responses to Xcc, transcriptomic profiles of these two genotypes following Xcc attack were compared by using the Affymetrix citrus genome GeneChip. ...

  12. treA Codifies for a Trehalase with Involvement in Xanthomonas citri subsp. citri Pathogenicity

    Science.gov (United States)

    Alexandrino, André Vessoni; Goto, Leandro Seiji; Novo-Mansur, Maria Teresa Marques

    2016-01-01

    Citrus canker, caused by the bacterium Xanthomonas citri subsp. citri (Xcc), is a severe disease of citrus. Xcc presents broad spectrum of citrus hosts including economically important species whereas X. fuscans subsp. aurantifolii–type C (XauC) causes a milder disease and only infects Citrus aurantifolia. Trehalase catalyzes hydrolysis of the disaccharide trehalose, a sugar that has been reported to be related to Xcc pathogenicity. We expressed the recombinant gene product and assessed Xcc trehalase structural and kinetics data. The recombinant protein presented 42.7% of secondary structures in α-helix and 13% in β-sheets, no quaternary structure in solution, and Michaelis-Menten constant (KM) of 0.077 mM and Vmax 55.308 μMol glucose.min-1.mg protein-1 for trehalose. A Xcc mutant strain (XccΔtreA) was produced by gene deletion from Xcc genome. Enzymatic activity of trehalase was determined in Xcc, XauC and XccΔtreA cellular lysates, showing the highest values for XauC in in vitro infective condition and no activity for XccΔtreA. Finally, leaves of Citrus aurantifolia infected with XccΔtreA showed much more drenching and necrosis than those infected by wild type Xcc. We concluded that trehalase contributes to alleviate bacterial virulence and that inability for trehalose hydrolysis may promote higher Xcc infectivity. PMID:27611974

  13. treA Codifies for a Trehalase with Involvement in Xanthomonas citri subsp. citri Pathogenicity.

    Science.gov (United States)

    Alexandrino, André Vessoni; Goto, Leandro Seiji; Novo-Mansur, Maria Teresa Marques

    2016-01-01

    Citrus canker, caused by the bacterium Xanthomonas citri subsp. citri (Xcc), is a severe disease of citrus. Xcc presents broad spectrum of citrus hosts including economically important species whereas X. fuscans subsp. aurantifolii-type C (XauC) causes a milder disease and only infects Citrus aurantifolia. Trehalase catalyzes hydrolysis of the disaccharide trehalose, a sugar that has been reported to be related to Xcc pathogenicity. We expressed the recombinant gene product and assessed Xcc trehalase structural and kinetics data. The recombinant protein presented 42.7% of secondary structures in α-helix and 13% in β-sheets, no quaternary structure in solution, and Michaelis-Menten constant (KM) of 0.077 mM and Vmax 55.308 μMol glucose.min-1.mg protein-1 for trehalose. A Xcc mutant strain (XccΔtreA) was produced by gene deletion from Xcc genome. Enzymatic activity of trehalase was determined in Xcc, XauC and XccΔtreA cellular lysates, showing the highest values for XauC in in vitro infective condition and no activity for XccΔtreA. Finally, leaves of Citrus aurantifolia infected with XccΔtreA showed much more drenching and necrosis than those infected by wild type Xcc. We concluded that trehalase contributes to alleviate bacterial virulence and that inability for trehalose hydrolysis may promote higher Xcc infectivity. PMID:27611974

  14. Bioactive organocopper compound from Pseudomonas aeruginosa inhibits the growth of Xanthomonas citri subsp. citri

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    Admilton Gonçalves de Oliveira

    2016-02-01

    Full Text Available Citrus canker is a lot destructive disease of citrus species. The challenge is to find new compounds that show strong antibiotic activity, low toxicity to plants and the environment. The objectives of the present study are (1 produce, purify and evaluate the antibiotic activity of secondary metabolites produced by induction by P. aeruginosa LV strain in vitro against Xanthomonas citri subsp. citri (strain 306, (2 study the potential for semi-purified secondary metabolites on foliar application to control citrus canker under greenhouse conditions, (3 identify the antibiotic activity in orange leaf mesophyll infected with strain 306 by electron microscopy. Two pure bioactive compounds were isolated, organocopper antibiotic compound and phenazine-1-carboxamide. The phenazine-1-carboxamide did not show any antibiotic activity under the experimental conditions used in this study. The organocopper antibiotic compound showed a high level of antibiotic activity with a minimum inhibitory concentration of 0.12 µg mL-1. In greenhouse tests for control of citrus canker in orange trees, the semi-purified fraction F3d, reduced lesion formation about 97%. The concentration used was five hundred times lower than recommended commercial product of metallic copper-based. Electron microscopy showed that F3d altered the exopolysaccharide matrix and causing cell lysis of the pathogen inside the citrus canker lesions. These results suggest that secondary metabolites produced by induction by P. aeruginosa LV strain has a high potential to be used as a bioproduct to control citrus canker.

  15. A protein expression system for tandem affinity purification in Xanthomonas citri subsp. citri

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    Giordanni C. Dantas

    2016-06-01

    Full Text Available Abstract Citrus canker, caused by the Gram-negative bacterium Xanthomonas citri subsp. citri (Xac, is one of the most devastating diseases to affect citrus crops. There is no treatment for citrus canker; effective control against the spread of Xac is usually achieved by the elimination of affected plants along with that of asymptomatic neighbors. An in depth understanding of the pathogen is the keystone for understanding of the disease; to this effect we are committed to the development of strategies to ease the study of Xac. Genome sequencing and annotation of Xac revealed that ∼37% of the genome is composed of hypothetical ORFs. To start a systematic characterization of novel factors encoded by Xac, we constructed integrative-vectors for protein expression specific to this bacterium. The vectors allow for the production of TAP-tagged proteins in Xac under the regulation of the xylose promoter. In this study, we show that a TAP-expression vector, integrated into the amy locus of Xac, does not compromise its virulence. Furthermore, our results also demonstrate that the polypeptide TAP can be overproduced in Xac and purified from the soluble phase of cell extracts. Our results substantiate the use of our vectors for protein expression in Xac thus contributing a novel tool for the characterization of proteins and protein complexes generated by this bacterium in vivo.

  16. A protein expression system for tandem affinity purification in Xanthomonas citri subsp. citri.

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    Dantas, Giordanni C; Martins, Paula M M; Martins, Daniela A B; Gomes, Eleni; Ferreira, Henrique

    2016-01-01

    Citrus canker, caused by the Gram-negative bacterium Xanthomonas citri subsp. citri (Xac), is one of the most devastating diseases to affect citrus crops. There is no treatment for citrus canker; effective control against the spread of Xac is usually achieved by the elimination of affected plants along with that of asymptomatic neighbors. An in depth understanding of the pathogen is the keystone for understanding of the disease; to this effect we are committed to the development of strategies to ease the study of Xac. Genome sequencing and annotation of Xac revealed that ∼37% of the genome is composed of hypothetical ORFs. To start a systematic characterization of novel factors encoded by Xac, we constructed integrative-vectors for protein expression specific to this bacterium. The vectors allow for the production of TAP-tagged proteins in Xac under the regulation of the xylose promoter. In this study, we show that a TAP-expression vector, integrated into the amy locus of Xac, does not compromise its virulence. Furthermore, our results also demonstrate that the polypeptide TAP can be overproduced in Xac and purified from the soluble phase of cell extracts. Our results substantiate the use of our vectors for protein expression in Xac thus contributing a novel tool for the characterization of proteins and protein complexes generated by this bacterium in vivo. PMID:26991273

  17. In Vitro and In Vivo Antibacterial Activity of Some Organic and Inorganic Salts Against Asiatic Citrus Canker Agent Xanthomonas Citri Subsp. Citri

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    Vahideh Hasabi

    2014-06-01

    Full Text Available Asiatic citrus canker caused by Xanthomonas citri subsp. citri is becoming a disease of high economic impact, affecting all types of important citrus crops. In this study, the potential antibacterial activity of ten organic and inorganic salts on X. citri subsp. citri and on citrus canker disease development was evaluated. Among the salt compounds, copper, iron and zinc inorganic salts particularly zinc (with the highest diameter of inhibition, the lowest MIC and MBC values and the highest bacterial growth inhibitory effect had direct antibacterial activity and strongly reduced the development of canker disease and bacterial population of lime plants.

  18. Non-host defense response in a novel Arabidopsis-Xanthomonas citri subsp. citri pathosystem.

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    Chuanfu An

    Full Text Available Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc, is one of the most destructive diseases of citrus. Progress of breeding citrus canker-resistant varieties is modest due to limited resistant germplasm resources and lack of candidate genes for genetic manipulation. The objective of this study is to establish a novel heterologous pathosystem between Xcc and the well-established model plant Arabidopsis thaliana for defense mechanism dissection and resistance gene identification. Our results indicate that Xcc bacteria neither grow nor decline in Arabidopsis, but induce multiple defense responses including callose deposition, reactive oxygen species and salicylic aicd (SA production, and defense gene expression, indicating that Xcc activates non-host resistance in Arabidopsis. Moreover, Xcc-induced defense gene expression is suppressed or attenuated in several well-characterized SA signaling mutants including eds1, pad4, eds5, sid2, and npr1. Interestingly, resistance to Xcc is compromised only in eds1, pad4, and eds5, but not in sid2 and npr1. However, combining sid2 and npr1 in the sid2npr1 double mutant compromises resistance to Xcc, suggesting genetic interactions likely exist between SID2 and NPR1 in the non-host resistance against Xcc in Arabidopsis. These results demonstrate that the SA signaling pathway plays a critical role in regulating non-host defense against Xcc in Arabidopsis and suggest that the SA signaling pathway genes may hold great potential for breeding citrus canker-resistant varieties through modern gene transfer technology.

  19. Proteome of the phytopathogen Xanthomonas citri subsp. citri: a global expression profile

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    Ferro Jesus A

    2010-11-01

    Full Text Available Abstract Background Citrus canker is a disease caused by Xantomonas citri subsp.citri (Xac, and has emerged as one of the major threats to the worldwide citrus crop because it affects all commercial citrus varieties, decreases the production and quality of the fruits and can spread rapidly in citrus growing areas. In this work, the first proteome of Xac was analyzed using two methodologies, two-dimensional liquid chromatography (2D LC and tandem mass spectrometry (MS/MS. Results In order to gain insight into the metabolism of Xac, cells were grown on two different media (NB - Nutrient Broth and TSE - Tryptone Sucrose broth enriched with glutamic acid, and proteins were proteolyzed with trypsin and examined by 2D LC-MS/MS. Approximately 39% of all predicted proteins by annotation of Xac were identified with their component peptides unambiguously assigned to tandem mass spectra. The proteins, about 1,100, were distributed in all annotated functional categories. Conclusions This is the first proteomic reference map for the most aggressive strain of Xanthomonas pathogen of all orange varieties. The compilation of metabolic pathways involved with bacterial growth showed that Xac expresses a complete central and intermediary metabolism, replication, transcription and translation machineries and regulation factors, distinct membrane transporters (ABC, MFS and pumps and receptors (MCP, TonB dependent and metabolites acquisition, two-component systems (sensor and regulatory components and response regulators. These data corroborate the growth curve in vitro and are the first reports indicating that many of these genome annotated genes are translated into operative in Xac. This proteomic analysis also provided information regarding the influence of culture medium on growth and protein expression of Xac.

  20. The small and large subunits of carbamoyl-phosphate synthase exhibit diverse contributions to pathogenicity in Xanthomonas citri subsp. citri

    Institute of Scientific and Technical Information of China (English)

    Guo Jing; SonG Xue; Zou Li-fang; Zou Hua-song; CHen Gong-you

    2015-01-01

    Carbamoyl-phosphate synthase plays a vital role in the carbon and nitrogen metabolism cycles. In Xanthomonas citri subsp. citri, carA and carB encode the smal and large subunits of carbamoyl-phosphate synthase, respectively. The deletion mutation of the coding regions revealed that carA did not affect any of the phenotypes, while carB played multiple roles in pathogenicity. The deletion of carB rendered the loss of pathogenicity in host plants and the ability to induce a hyper-sensitive reaction in the non-hosts. Quantitative reverse transcription-PCR assays indicated that 11 hrp genes coding the type III secretion system were suppressed when interacting with citrus plants. The mutation in carB also affected bacterial utilization of several carbon and nitrogen resources in minimal medium MMX and extracel ular enzyme activities. These data demonstrated that only the large subunit of carbamoyl-phosphate synthase was essential for canker development by X. citri subsp. citri.

  1. Comparison of Droplet Digital PCR and Quantitative PCR Assays for Quantitative Detection of Xanthomonas citri Subsp. citri

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    Yin, Youping; Wang, Zhongkang

    2016-01-01

    Droplet digital polymerase chain reaction (ddPCR) is a novel molecular biology technique providing absolute quantification of target nucleic acids without the need for an external calibrator. Despite its emerging applications in medical diagnosis, there are few reports of its use for the detection of plant pathogens. This work was designed to assess the diagnosis potential of the ddPCR for absolute quantitative detection of Xanthomonas citri subsp. citri, a quarantine plant pathogenic bacterium that causes citrus bacterial canker in susceptible Citrus species. We transferred an established quantitative PCR (qPCR) assay for citrus bacterial canker diagnosis directly to the ddPCR format and compared the performance of the two methods. The qPCR assay has a broader dynamic range compared to the ddPCR assay and the ddPCR assay has a significantly higher degree of sensitivity compared to the qPCR assay. The influence of PCR inhibitors can be reduced considerably in the ddPCR assay because the collection of end-point fluorescent signals and the counting of binomial events (positive or negative droplets) are associated with a Poisson algorithm. The ddPCR assay also shows lower coefficient of variation compared to the qPCR assay especially in low target concentration. The linear association of the measurements by ddPCR and qPCR assays is strong (Pearson correlation = 0.8633; P<0.001). Receiver operating characteristic analysis indicates the ddPCR methodology is a more robust approach for diagnosis of citrus bacterial canker. In summary, the results demonstrated that the ddPCR assay has the potential for the quantitative detection of X. citri subsp. citri with high precision and accuracy as compared with the results from qPCR assay. Further studies are required to evaluate and validate the value of ddPCR technology in the diagnosis of plant disease and quarantine applications. PMID:27427975

  2. Effect of X-irradiation on Citrus Canker Pathogen Xanthomonas citri subsp. citri of Satsuma Mandarin Fruits

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    Min-A Song

    2015-12-01

    Full Text Available Citrus canker caused by Xanthomonas citri subsp. citri (Xcc is one of the most important bacterial diseases of citrus. Because citrus canker is not found in many countries including European Union and Australia, Xcc is strictly regulated in order to prevent its spread. In this study, the effects of X-irradiation on Xcc growth either in the suspension or on the surface of citrus fruits were investigated. The suspension containing 1×10⁷ cfu/ml of Xcc was irradiated with different absorbed doses of X-irradiation ranging from 50 to 400 Gy. The results showed that Xcc was fully dead at 400 Gy of X-irradiation. To determine the effect of X-irradiation on quarantine, the Xcc-inoculated citrus fruits were irradiated with different X-ray doses at which Xcc was completely inhibited by an irradiation dose of 250 Gy. The D₁₀ value for Xcc on citrus fruits was found to be 97 Gy, indicating the possibility of direct application on citrus quarantine without any side sterilizer. Beside, presence of Xcc on the surface of asymptomatic citrus fruits obtained from citrus canker-infected orchards was noted. It indicated that the exporting citrus fruits need any treatment so that Xcc on the citrus fruits should be completely eliminated. Based on these results, ionizing radiation can be considered as an alternative method of eradicating Xcc for export of citrus fruits.

  3. Reaction of detached leaves from different varieties of sweet orange to inoculation with Xanthomonas citri subsp. citri

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    Aline Maria Orbolato Gonçalves-Zuliani

    2016-06-01

    Full Text Available ABSTRACT Citrus genotypes show a broad range of resistance to infection with Xanthomonas citri subsp citri (Xcc, the causal agent of Asiatic citrus canker (ACC. The aim of this study was to evaluate a detached leaf inoculation method to compare nine different citrus genotypes that exhibit varied resistance levels to ACC, and to evaluate infection, colonization and symptom development of the varieties by using Scanning Electron Microscopy (SEM. Inoculation of Xcc in the leaves was carried out by producing injuries with needles. Lesion diameters were measured at 7, 10 and 13 days after inoculation (DAI. The variety Pera IAC was most resistant to the pathogen and had lesions with smaller diameters, while the variety Washington was most susceptible and had the largest lesions, indicating low resistance to Xcc. SEM images were taken from the lesion development, and sections were obtained from the disease lesions in the tested varieties. The most resistant variety, Pera IAC, had smaller stomatal openings and produced greater quantity of foliar exudates, compared with the variety Washington. We hypothesize that the exudates may contain Xcc toxic compounds and thus may be a defense mechanism against infection by Xcc, but further research is required to establish any antibiotic effects of the exudates against citrus canker.

  4. Comparison of Droplet Digital PCR and Quantitative PCR Assays for Quantitative Detection of Xanthomonas citri Subsp. citri.

    Science.gov (United States)

    Zhao, Yun; Xia, Qingyan; Yin, Youping; Wang, Zhongkang

    2016-01-01

    Droplet digital polymerase chain reaction (ddPCR) is a novel molecular biology technique providing absolute quantification of target nucleic acids without the need for an external calibrator. Despite its emerging applications in medical diagnosis, there are few reports of its use for the detection of plant pathogens. This work was designed to assess the diagnosis potential of the ddPCR for absolute quantitative detection of Xanthomonas citri subsp. citri, a quarantine plant pathogenic bacterium that causes citrus bacterial canker in susceptible Citrus species. We transferred an established quantitative PCR (qPCR) assay for citrus bacterial canker diagnosis directly to the ddPCR format and compared the performance of the two methods. The qPCR assay has a broader dynamic range compared to the ddPCR assay and the ddPCR assay has a significantly higher degree of sensitivity compared to the qPCR assay. The influence of PCR inhibitors can be reduced considerably in the ddPCR assay because the collection of end-point fluorescent signals and the counting of binomial events (positive or negative droplets) are associated with a Poisson algorithm. The ddPCR assay also shows lower coefficient of variation compared to the qPCR assay especially in low target concentration. The linear association of the measurements by ddPCR and qPCR assays is strong (Pearson correlation = 0.8633; Pvalue of ddPCR technology in the diagnosis of plant disease and quarantine applications. PMID:27427975

  5. Different transcriptional response to Xanthomonas citri subsp. citri between kumquat and sweet orange with contrasting canker tolerance.

    Directory of Open Access Journals (Sweden)

    Xing-Zheng Fu

    Full Text Available Citrus canker disease caused by Xanthomonas citri subsp. citri (Xcc is one of the most devastating biotic stresses affecting the citrus industry. Meiwa kumquat (Fortunella crassifolia is canker-resistant, while Newhall navel orange (Citrus sinensis Osbeck is canker-sensitive. To understand the molecular mechanisms underlying the differences in responses to Xcc, transcriptomic profiles of these two genotypes following Xcc attack were compared by using the Affymetrix citrus genome GeneChip. A total of 794 and 1324 differentially expressed genes (DEGs were identified as canker-responsive genes in Meiwa and Newhall, respectively. Of these, 230 genes were expressed in common between both genotypes, while 564 and 1094 genes were only significantly expressed in either Meiwa or Newhall. Gene ontology (GO annotation and Singular Enrichment Analysis (SEA of the DEGs showed that genes related to the cell wall and polysaccharide metabolism were induced for basic defense in both Meiwa and Newhall, such as chitinase, glucanase and thaumatin-like protein. Moreover, apart from inducing basic defense, Meiwa showed specially upregulated expression of several genes involved in the response to biotic stimulus, defense response, and cation binding as comparing with Newhall. And in Newhall, abundant photosynthesis-related genes were significantly down-regulated, which may be in order to ensure the basic defense. This study revealed different molecular responses to canker disease in Meiwa and Newhall, affording insight into the response to canker and providing valuable information for the identification of potential genes for engineering canker tolerance in the future.

  6. Bismerthiazol Inhibits Xanthomonas citri subsp. citri Growth and Induces Differential Expression of Citrus Defense-Related Genes.

    Science.gov (United States)

    Yu, Xiaoyue; Armstrong, Cheryl M; Zhou, Mingguo; Duan, Yongping

    2016-07-01

    Citrus canker, caused by Xanthomonas citri ssp. citri, is a serious disease that causes substantial economic losses to the citrus industry worldwide. The bactericide bismerthiazol has been used to control rice bacterial blight (X. oryzae pv. oryzae). In this paper, we demonstrate that bismerthiazol can effectively control citrus canker by both inhibiting the growth of X. citri ssp. citri and triggering the plant's host defense response through the expression of several pathogenesis-related genes (PR1, PR2, CHI, and RpRd1) and the nonexpresser of PR genes (NPR1, NPR2, and NPR3) in 'Duncan' grapefruit, especially at early treatment times. In addition, we found that bismerthiazol induced the expression of the marker genes CitCHS and CitCHI in the flavonoid pathway and the PAL1 (phenylalanine ammonia lyase 1) gene in the salicylic acid (SA) biosynthesis pathway at different time points. Moreover, bismerthiazol also induced the expression of the priming defense-associated gene AZI1. Taken together, these results indicate that the induction of the defense response in 'Duncan' grapefruit by bismerthiazol may involve the SA signaling pathway and the priming defense and that bismerthiazol may serve as an alternative to copper bactericides for the control of citrus canker. PMID:26882850

  7. Establishment of EMA-PCR detection method of viable cells of Xanthomonas citri subsp.citri%柑橘溃疡病菌EMA-PCR快速活体检测技术的建立

    Institute of Scientific and Technical Information of China (English)

    熊书; 王中康; 卢小林; 殷幼平

    2013-01-01

    传统PCR方法不能诊断柑橘溃疡病菌(Xanthomonas citri subsp.citri Gabriel)的死活状态,往往导致假阳性检测结果.本研究将特异性核酸染料叠氮溴化乙锭(ethidium monoazide bromide,EMA)与PCR技术结合,旨在建立柑橘溃疡病活菌的快速检测技术.根据柑橘溃疡病菌独有的保守蛋白基因设计特异性引物扩增出278 bp的靶带,PCR反应的检测下限为25个细胞/25 μL或2.75 pg/25 μL.EMA-PCR结果表明:当卤钨灯曝光时间1 min,EMA终浓度为1.0 mg/L时,能有效抑制1.0×108 cfu/mL死菌的扩增;当EMA的浓度小于30 mg/L时,EMA对上述相同浓度活菌靶基因的扩增没有明显的抑制.EMA-PCR对死活混合菌的扩增表明,活菌数在6.875×101~6.875×105 cfu/PCR范围时,荧光强度与混合体系中活菌的对数值有线性关系.基于以上建立的EMA-PCR活体检测技术,对疑似带病柑橘材料进行检测,结果发现能降低柑橘溃疡病菌检测过程中的假阳性,有望为柑橘溃疡病的检疫检验提供更科学的技术手段.%Conventional PCR method can not distinguish live cells from dead cells of Xanthononas citri subsp.citri Gabriel,and false positives results can easily be obtained in detection process.Ethidium monoazide bromide (EMA) can selectively inhibit PCR amplification of DNA from dead cells.Therefore,in this study,EMA was combined with PCR to detect viable cells of X.citri subsp.citri.Firstly,primers (Xcc R/Xcc F) specific to X.citri subsp.citri were designed to amplify a 278 bp fragment.The minimum limit of detection was 25 cells/25 μL PCR volume or 2.75 pg/25 μ L PCR volume.The results of EMA-PCR showed that the optimized light exposure time was at least 1 min,allowing crosslinking of DNA by the EMA in dead cells and photolysing the free EMA in solution.The minimum amount of EMA to completely inhibit the PCR amplification of DNA derived from heat-killed cells was 1.0 mg/L.EMA less than 30 mg/L did not inhibit the PCR amplification

  8. Acción inhibitoria de una cepa de Zymomonas mobilis mobilis aislada de caña de azúcar sobre Xanthomonas citri subsp. citri, agente causal de la cancrosis de los cítricos Inhibition of Xanthomonas citri subsp. citri, causal agent of citrus canker, by a strain of Zymomonas mobilis mobilis isolated from sugarcane

    Directory of Open Access Journals (Sweden)

    María E. Romero

    2008-06-01

    Full Text Available Zymomonas mobilis mobilis (Zm produce factores antimicrobianos que actúan sobre un amplio espectro de microorganismos patógenos para el hombre, animales y plantas. Un problema importante a resolver en los tratamientos con antimicrobianos, es el desarrollo de resistencia a compuestos empleados actualmente, no siendo las bacterias fitopatógenas una excepción. En el presente trabajo se realizaron ensayos de antagonismo con células (pruebas de estrías cruzadas y sobrenadantes concentrados (Sc (por difusión en agar preparados a partir de cultivos de Zm (aislada de jugo de caña de azúcar producido en Tucumán, frente a la bacteria causal de la cancrosis: Xanthomonas citri subsp. citri. Se evaluaron aislamientos de Xcc sensibles (Xc y resistentes (Xcr a compuestos a base de cobre. Los resultados obtenidos mostraron que la bacteria testigo fue inhibida totalmente por las células de Zm, ejerciendo un efecto bactericida. En los ensayos de difusión en el agar se observó que tanto Xc, como Xcr fueron sensibles al Sc de Zm. Se sabe, por estudios anteriores, que los metabolitos de Zymomonas tienen un efecto deletéreo en la membrana celular de E. coli AB1133, inhibiéndose la respiración de la bacteria inmediatamente de agregado Sc (60 UA. En el presente trabajo se observó el mismo efecto, inhibición total de la respiración en Xc, luego del agregado del Sc (60 UA. Por lo observado, se deduce que el blanco de acción de los metabolitos antimicrobianos de Sc en Xc, sería el mismo que el de E. coli AB1133. Con los resultados obtenidos se considera de interés encarar el estudio de los compuestos de Zm para ser empleados en el control de enfermedades que afectan los cultivos de valor económico de la región, como es el caso de la cancrosis, como así también profundizar acerca de la acción de dichos metabolitos en la membrana de Xanthomonas citri subsp. citri.Zymomonas mobilis mobilis (Zm produces antimicrobial factors, which have an effect on

  9. The dual nature of trehalose in citrus canker disease: a virulence factor for Xanthomonas citri subsp. citri and a trigger for plant defence responses.

    Science.gov (United States)

    Piazza, Ainelén; Zimaro, Tamara; Garavaglia, Betiana S; Ficarra, Florencia A; Thomas, Ludivine; Marondedze, Claudius; Feil, Regina; Lunn, John E; Gehring, Chris; Ottado, Jorgelina; Gottig, Natalia

    2015-05-01

    Xanthomonas citri subsp. citri (Xcc) is a bacterial pathogen that causes citrus canker in susceptible Citrus spp. The Xcc genome contains genes encoding enzymes from three separate pathways of trehalose biosynthesis. Expression of genes encoding trehalose-6-phosphate synthase (otsA) and trehalose phosphatase (otsB) was highly induced during canker development, suggesting that the two-step pathway of trehalose biosynthesis via trehalose-6-phosphate has a function in pathogenesis. This pathway was eliminated from the bacterium by deletion of the otsA gene. The resulting XccΔotsA mutant produced less trehalose than the wild-type strain, was less resistant to salt and oxidative stresses, and was less able to colonize plant tissues. Gene expression and proteomic analyses of infected leaves showed that infection with XccΔotsA triggered only weak defence responses in the plant compared with infection with Xcc, and had less impact on the host plant's metabolism than the wild-type strain. These results suggested that trehalose of bacterial origin, synthesized via the otsA-otsB pathway, in Xcc, plays a role in modifying the host plant's metabolism to its own advantage but is also perceived by the plant as a sign of pathogen attack. Thus, trehalose biosynthesis has both positive and negative consequences for Xcc. On the one hand, it enables this bacterial pathogen to survive in the inhospitable environment of the leaf surface before infection and exploit the host plant's resources after infection, but on the other hand, it is a tell-tale sign of the pathogen's presence that triggers the plant to defend itself against infection. PMID:25770587

  10. Differential expression of pectolytic enzyme genes in Xanthomonas citri subsp. citri and demonstration that pectate lyase Pel3 is required for the formation of citrus canker.

    Science.gov (United States)

    Chang, Shih-Chieh; Deng, Wen-Ling; Huang, Hsiou-Chen; Chung, Kuang-Ren; Tzeng, Kuo-Ching

    2016-11-01

    Bacterial canker, caused by Xanthomonas citri subsp. citri (Xcc), is one of the most destructive diseases of citrus. The pectolytic enzymes produced by phytobacteria are important virulence factors involved in tissue maceration, electrolyte loss and cell death of host plants. In this study, the promoter activity of the pectolytic enzyme genes pel1, pel2, pel3, pglA, and peh-1 were investigated in Xcc XW19 strain using the β-glucuronidase (GUS) gene as a reporter. GUS activity expressed under the control of the pel1, pel3, pglA, and peh-1 gene promoters positively correlated with bacterial growth. These gene promoters displayed high GUS activity in the presence of sodium polypectate. In addition, the four genes were induced in XVM2 minimal medium. However, only pel1 was subjected to catabolite repression by glucose. GUS activity was significantly enhanced in the XW19-derived reporter strains after they were inoculated into the leaves of Mexican lime and grapefruit, suggesting the involvement of the pel1, pel3, pglA, and peh-1 genes in XW19 pathogenesis. The pel3 promoter produced the highest GUS activity under all test conditions, whereas no GUS activity was detected using the pel2 promoter in vitro and in planta. In comparison with wild type Xcc, a pel3 mutant generated from Xcc XW19 using unmarked mutagenesis displayed reduced growth and induced smaller canker lesions on the leaves of Mexican lime, demonstrating that Pel3 of Xcc strain XW19 is a virulence factor. PMID:27664718

  11. The dual nature of trehalose in citrus canker disease: a virulence factor for Xanthomonas citri subsp. citri and a trigger for plant defence responses.

    Science.gov (United States)

    Piazza, Ainelén; Zimaro, Tamara; Garavaglia, Betiana S; Ficarra, Florencia A; Thomas, Ludivine; Marondedze, Claudius; Feil, Regina; Lunn, John E; Gehring, Chris; Ottado, Jorgelina; Gottig, Natalia

    2015-05-01

    Xanthomonas citri subsp. citri (Xcc) is a bacterial pathogen that causes citrus canker in susceptible Citrus spp. The Xcc genome contains genes encoding enzymes from three separate pathways of trehalose biosynthesis. Expression of genes encoding trehalose-6-phosphate synthase (otsA) and trehalose phosphatase (otsB) was highly induced during canker development, suggesting that the two-step pathway of trehalose biosynthesis via trehalose-6-phosphate has a function in pathogenesis. This pathway was eliminated from the bacterium by deletion of the otsA gene. The resulting XccΔotsA mutant produced less trehalose than the wild-type strain, was less resistant to salt and oxidative stresses, and was less able to colonize plant tissues. Gene expression and proteomic analyses of infected leaves showed that infection with XccΔotsA triggered only weak defence responses in the plant compared with infection with Xcc, and had less impact on the host plant's metabolism than the wild-type strain. These results suggested that trehalose of bacterial origin, synthesized via the otsA-otsB pathway, in Xcc, plays a role in modifying the host plant's metabolism to its own advantage but is also perceived by the plant as a sign of pathogen attack. Thus, trehalose biosynthesis has both positive and negative consequences for Xcc. On the one hand, it enables this bacterial pathogen to survive in the inhospitable environment of the leaf surface before infection and exploit the host plant's resources after infection, but on the other hand, it is a tell-tale sign of the pathogen's presence that triggers the plant to defend itself against infection.

  12. The dual nature of trehalose in citrus canker disease: a virulence factor for Xanthomonas citri subsp. citri and a trigger for plant defence responses

    KAUST Repository

    Piazza, A.

    2015-03-14

    Xanthomonas citri subsp. citri (Xcc) is a bacterial pathogen that causes citrus canker in susceptible Citrus spp. The Xcc genome contains genes encoding enzymes from three separate pathways of trehalose biosynthesis. Expression of genes encoding trehalose-6-phosphate synthase (otsA) and trehalose phosphatase (otsB) was highly induced during canker development, suggesting that the two-step pathway of trehalose biosynthesis via trehalose-6-phosphate has a function in pathogenesis. This pathway was eliminated from the bacterium by deletion of the otsA gene. The resulting XccΔotsA mutant produced less trehalose than the wild-type strain, was less resistant to salt and oxidative stresses, and was less able to colonize plant tissues. Gene expression and proteomic analyses of infected leaves showed that infection with XccΔotsA triggered only weak defence responses in the plant compared with infection with Xcc, and had less impact on the host plant\\'s metabolism than the wild-type strain. These results suggested that trehalose of bacterial origin, synthesized via the otsA-otsB pathway, in Xcc, plays a role in modifying the host plant\\'s metabolism to its own advantage but is also perceived by the plant as a sign of pathogen attack. Thus, trehalose biosynthesis has both positive and negative consequences for Xcc. On the one hand, it enables this bacterial pathogen to survive in the inhospitable environment of the leaf surface before infection and exploit the host plant\\'s resources after infection, but on the other hand, it is a tell-tale sign of the pathogen\\'s presence that triggers the plant to defend itself against infection. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  13. The gpsX gene encoding a glycosyltransferase is important for polysaccharide production and required for full virulence in Xanthomonas citri subsp. citri

    Directory of Open Access Journals (Sweden)

    Li Jinyun

    2012-03-01

    Full Text Available Abstract Background The Gram-negative bacterium Xanthomonas citri subsp. citri (Xac causes citrus canker, one of the most destructive diseases of citrus worldwide. In our previous work, a transposon mutant of Xac strain 306 with an insertion in the XAC3110 locus was isolated in a screening that aimed at identifying genes related to biofilm formation. The XAC3110 locus was named as bdp24 for biofilm-defective phenotype and the mutant was observed to be affected in extracellular polysaccharide (EPS and lipopolysaccharide (LPS biosynthesis and cell motility. In this study, we further characterized the bdp24 (XAC3110 gene (designated as gpsX using genetic complementation assays and expanded the knowledge about the function of the gpsX gene in Xac pathogenesis by investigating the roles of gpsX in EPS and LPS production, cell motility, biofilm formation on host leaves, stress tolerance, growth in planta, and host virulence of the citrus canker bacterium. Results The gpsX gene encodes a putative glycosyltransferase, which is highly conserved in the sequenced strains of Xanthomonas. Mutation of gpsX resulted in a significant reduction of the amount of EPS and loss of two LPS bands visualized on sodium dodecylsulphate- polyacrylamide gels. Biofilm assays revealed that the gpsX mutation affected biofilm formation by Xac on abiotic and biotic surfaces. The gpsX mutant showed delayed bacterial growth and caused reduced development of disease symptoms in susceptible citrus leaves. The gpsX mutant was more sensitive than the wild-type strain to various stresses, including the H2O2 oxidative stress. The mutant also showed attenuated ability in cell motility but not in flagellar formation. Quantitative reverse transcription-PCR assays indicated that mutation of gpsX did not affect the expression of virulence genes such as pthA in Xac strain 306. The affected phenotypes of the gpsX mutant could be complemented to wild-type levels by the intact gpsX gene

  14. KatG, the Bifunctional Catalase of Xanthomonas citri subsp. citri, Responds to Hydrogen Peroxide and Contributes to Epiphytic Survival on Citrus Leaves.

    Science.gov (United States)

    Tondo, María Laura; Delprato, María Laura; Kraiselburd, Ivana; Fernández Zenoff, María Verónica; Farías, María Eugenia; Orellano, Elena G

    2016-01-01

    Xanthomonas citri subsp. citri (Xcc) is the bacterium responsible for citrus canker. This bacterium is exposed to reactive oxygen species (ROS) at different points during its life cycle, including those normally produced by aerobic respiration or upon exposition to ultraviolet (UV) radiation. Moreover, ROS are key components of the host immune response. Among enzymatic ROS-detoxifying mechanisms, catalases eliminate H2O2, avoiding the potential damage caused by this specie. Xcc genome includes four catalase genes. In this work, we studied the physiological role of KatG, the only bifunctional catalase of Xcc, through the construction and characterization of a modified strain (XcckatG), carrying an insertional mutation in the katG gene. First, we evaluated the involvement of KatG in the bacterial adaptive response to H2O2. XcckatG cultures exhibited lower catalase activity than those of the wild-type strain, and this activity was not induced upon treatment with sub-lethal doses of H2O2. Moreover, the KatG-deficient mutant exhibited decreased tolerance to H2O2 toxicity compared to wild-type cells and accumulated high intracellular levels of peroxides upon exposure to sub-lethal concentrations of H2O2. To further study the role of KatG in Xcc physiology, we evaluated bacterial survival upon exposure to UV-A or UV-B radiation. In both conditions, XcckatG showed a high mortality in comparison to Xcc wild-type. Finally, we studied the development of bacterial biofilms. While structured biofilms were observed for the Xcc wild-type, the development of these structures was impaired for XcckatG. Based on these results, we demonstrated that KatG is responsible for Xcc adaptive response to H2O2 and a key component of the bacterial response to oxidative stress. Moreover, this enzyme plays an important role during Xcc epiphytic survival, being essential for biofilm formation and UV resistance.

  15. KatG, the Bifunctional Catalase of Xanthomonas citri subsp. citri, Responds to Hydrogen Peroxide and Contributes to Epiphytic Survival on Citrus Leaves.

    Directory of Open Access Journals (Sweden)

    María Laura Tondo

    Full Text Available Xanthomonas citri subsp. citri (Xcc is the bacterium responsible for citrus canker. This bacterium is exposed to reactive oxygen species (ROS at different points during its life cycle, including those normally produced by aerobic respiration or upon exposition to ultraviolet (UV radiation. Moreover, ROS are key components of the host immune response. Among enzymatic ROS-detoxifying mechanisms, catalases eliminate H2O2, avoiding the potential damage caused by this specie. Xcc genome includes four catalase genes. In this work, we studied the physiological role of KatG, the only bifunctional catalase of Xcc, through the construction and characterization of a modified strain (XcckatG, carrying an insertional mutation in the katG gene. First, we evaluated the involvement of KatG in the bacterial adaptive response to H2O2. XcckatG cultures exhibited lower catalase activity than those of the wild-type strain, and this activity was not induced upon treatment with sub-lethal doses of H2O2. Moreover, the KatG-deficient mutant exhibited decreased tolerance to H2O2 toxicity compared to wild-type cells and accumulated high intracellular levels of peroxides upon exposure to sub-lethal concentrations of H2O2. To further study the role of KatG in Xcc physiology, we evaluated bacterial survival upon exposure to UV-A or UV-B radiation. In both conditions, XcckatG showed a high mortality in comparison to Xcc wild-type. Finally, we studied the development of bacterial biofilms. While structured biofilms were observed for the Xcc wild-type, the development of these structures was impaired for XcckatG. Based on these results, we demonstrated that KatG is responsible for Xcc adaptive response to H2O2 and a key component of the bacterial response to oxidative stress. Moreover, this enzyme plays an important role during Xcc epiphytic survival, being essential for biofilm formation and UV resistance.

  16. KatG, the Bifunctional Catalase of Xanthomonas citri subsp. citri, Responds to Hydrogen Peroxide and Contributes to Epiphytic Survival on Citrus Leaves.

    Science.gov (United States)

    Tondo, María Laura; Delprato, María Laura; Kraiselburd, Ivana; Fernández Zenoff, María Verónica; Farías, María Eugenia; Orellano, Elena G

    2016-01-01

    Xanthomonas citri subsp. citri (Xcc) is the bacterium responsible for citrus canker. This bacterium is exposed to reactive oxygen species (ROS) at different points during its life cycle, including those normally produced by aerobic respiration or upon exposition to ultraviolet (UV) radiation. Moreover, ROS are key components of the host immune response. Among enzymatic ROS-detoxifying mechanisms, catalases eliminate H2O2, avoiding the potential damage caused by this specie. Xcc genome includes four catalase genes. In this work, we studied the physiological role of KatG, the only bifunctional catalase of Xcc, through the construction and characterization of a modified strain (XcckatG), carrying an insertional mutation in the katG gene. First, we evaluated the involvement of KatG in the bacterial adaptive response to H2O2. XcckatG cultures exhibited lower catalase activity than those of the wild-type strain, and this activity was not induced upon treatment with sub-lethal doses of H2O2. Moreover, the KatG-deficient mutant exhibited decreased tolerance to H2O2 toxicity compared to wild-type cells and accumulated high intracellular levels of peroxides upon exposure to sub-lethal concentrations of H2O2. To further study the role of KatG in Xcc physiology, we evaluated bacterial survival upon exposure to UV-A or UV-B radiation. In both conditions, XcckatG showed a high mortality in comparison to Xcc wild-type. Finally, we studied the development of bacterial biofilms. While structured biofilms were observed for the Xcc wild-type, the development of these structures was impaired for XcckatG. Based on these results, we demonstrated that KatG is responsible for Xcc adaptive response to H2O2 and a key component of the bacterial response to oxidative stress. Moreover, this enzyme plays an important role during Xcc epiphytic survival, being essential for biofilm formation and UV resistance. PMID:26990197

  17. Characterization of three linalool synthase genes from Citrus unshiu Marc. and analysis of linalool-mediated resistance against Xanthomonas citri subsp. citri and Penicilium italicum in citrus leaves and fruits.

    Science.gov (United States)

    Shimada, Takehiko; Endo, Tomoko; Fujii, Hiroshi; Rodríguez, Ana; Peña, Leandro; Omura, Mitsuo

    2014-12-01

    Three cDNA clones from Satsuma mandarin (Citrus unshiu Marc.) were isolated and expressed in Escherichia coli. CuSTS3-1 and CuSTS3-2 encode linalool synthases and CuSTS4 encodes a nerolidol/linalool synthase. Transcripts of CuSTS3-1, CuSTS3-2 and CuSTS4 were abundant in young fruit at 60 days after flowering (DAF), flowers and leaves, respectively. Treatments with Xanthomonas citri subsp. citri (XCC), the causal agent of citrus canker and Penicillium italicum (PI), the cause of post-harvest fruit decay, and wounding up-regulated CuSTS3-1 in fruit and mainly CuSTS4 in leaves. Linalool, citral, geraniol and citronellol showed strong antibacterial and antifungal activities against XCC and PI in vitro, while most other mono-and sesquiterpenes, including limonene and gamma-terpinene, did not. Linalool, used at levels similar to those present in resistant Ponkan mandarin (Citrus reticulata Blanco) leaves, was able to inhibit growth of XCC in vitro. Compared to other five citrus types, linalool accumulated at extraordinarily high levels in Ponkan mandarin leaves and was released at high amounts from their leaves, while it was hardly detectable in the most susceptible species, indicating that linalool biosynthesis and accumulation might be involved in plant defense against bacterial and fungal pathogens and be associated with field resistance to citrus canker. PMID:25443842

  18. Characterization of three linalool synthase genes from Citrus unshiu Marc. and analysis of linalool-mediated resistance against Xanthomonas citri subsp. citri and Penicilium italicum in citrus leaves and fruits.

    Science.gov (United States)

    Shimada, Takehiko; Endo, Tomoko; Fujii, Hiroshi; Rodríguez, Ana; Peña, Leandro; Omura, Mitsuo

    2014-12-01

    Three cDNA clones from Satsuma mandarin (Citrus unshiu Marc.) were isolated and expressed in Escherichia coli. CuSTS3-1 and CuSTS3-2 encode linalool synthases and CuSTS4 encodes a nerolidol/linalool synthase. Transcripts of CuSTS3-1, CuSTS3-2 and CuSTS4 were abundant in young fruit at 60 days after flowering (DAF), flowers and leaves, respectively. Treatments with Xanthomonas citri subsp. citri (XCC), the causal agent of citrus canker and Penicillium italicum (PI), the cause of post-harvest fruit decay, and wounding up-regulated CuSTS3-1 in fruit and mainly CuSTS4 in leaves. Linalool, citral, geraniol and citronellol showed strong antibacterial and antifungal activities against XCC and PI in vitro, while most other mono-and sesquiterpenes, including limonene and gamma-terpinene, did not. Linalool, used at levels similar to those present in resistant Ponkan mandarin (Citrus reticulata Blanco) leaves, was able to inhibit growth of XCC in vitro. Compared to other five citrus types, linalool accumulated at extraordinarily high levels in Ponkan mandarin leaves and was released at high amounts from their leaves, while it was hardly detectable in the most susceptible species, indicating that linalool biosynthesis and accumulation might be involved in plant defense against bacterial and fungal pathogens and be associated with field resistance to citrus canker.

  19. Avaliação da resistência de variedades de Citrus spp. à Xanthomonas citri subsp. citri na região Noroeste Paranaense, em condições de campo

    Directory of Open Access Journals (Sweden)

    Rosa Gabriella Vargas

    2013-12-01

    Full Text Available A identificação de cultivares com determinados níveis de resistência ao cancro cítrico, com características agronômicas e comerciais desejáveis, assume grande importância para o manejo desta doença. A avaliação de genótipos promissores pode ser fetuada em condições controladas ou em campo. O trabalho teve como objetivo avaliar genótipos de laranja doce (Citrus sinensis, tangerinas (Citrus reticulata e híbridos quanto à resistência ao cancro cítrico, em diferentes épocas de avaliação. O experimento foi conduzido em pomar experimental no município de Maringá, Paraná. Para a determinação da severidade média da doença, foram utilizadas escalas diagramáticas, sendo avaliadas quatro plantas por bloco e amostrados ramos na porção mediana de cada planta. Além disso, foi calculada a Área Abaixo da Curva de Progresso da Severidade (AACPS. De acordo com os dados obtidos, ocorreram diferenças significativas na severidade e na AACPS, ao longo das avaliações, sendo que a severidade variou de 0,25% a 4,88% e a AACPS de 49,80 a 742,65. As variedades cítricas Tang. Ponkan, Rosehaugh Nartjee, Harris, De wildt, Dekopon, Lee, África do Sul, Tarocco#23, Solid Scarlet, Satsuma Okitsu SPA 29, Cristalina, Shamouti e Pêra Olimpia se destacaram e apresentaram as menores médias de severidade, sendo essas classificadas como resistentes. Os resultados sugerem que esses genótipos podem ser importantes ferramentas nos programas de melhoramento de genótipos de citros, visando resistência a Xanthomonas citri subsp. citri.

  20. Disrupting mating behavior of Diaphorina citri (Liviidae)

    Science.gov (United States)

    Severe economic damage from citrus greening disease, caused by ‘Candidatus Liberibacter asiaticus’ bacteria, has stimulated development of methods to reduce mating and reproduction in populations of its insect vector, Diaphorina citri (Hemiptera: Liviidae). Male D. citri find mating partners by walk...

  1. Proposal to conserve the name Phomopsis citri H.S. Fawc. (Diaporthe citri), with a conserved type, against Phomopsis citri (Sacc.) Traverso & Spessa (Ascomycota, Diaporthales, Diaporthaceae)

    Science.gov (United States)

    The name Diaporthe citri applies to a fungus that causes a disease on Citrus known as melanose or stem end rot of mature fruit after harvest and occurs widely in North America and Asia. Initially described as the illegitimate Phomopsis citri H.S. Fawc. 1912, non P. citri (Sacc.) Traverso & Spessa 19...

  2. The cys regulon of Xanthomonas citri

    International Nuclear Information System (INIS)

    Full text: In Escherichia coli, genes involved in metabolic pathway of sulfate and sulfonate compounds are clustered in a cys regulon, which includes three ABC transport system (operons: sbpcysWUA; ssuABC and tauABC), thirteen genes involved in the sulfur reduction (ssuDE; tauD and cysDNCHIJGK) and two regulatory proteins that belong to LysR transcription family: CysB and Cbl. Notably, a search and comparative analysis of these genes in the genomes of the citrus pathogen Xanthomonas citri and other phylogenetically related Xanthomonas species revealed the presence of genes involved with alkanesulfonate, sulfate ester and taurine, only in X. citri, suggesting that proteins from this regulon might be associated with pathogenicity in citrus. Using the molecular modeling associated with a system biology view, we modeled all the protein structures of the X. citri cys regulon as well as characterized the important residues forming the putative active sites. Comparison with orthologs from different microorganisms was made in order to get a phylogenetic relationships. We showed that proteins that are responsible for the affinity and specificity of the alkanesulfonate, sulfate and taurine transport systems conserved the residues involved in the sulfate coordination but are organized in different branches in evolution. Inside these phylogenetic branches, proteins involved in the sulfate transporter are highly conserved when compared to the others. Moreover, we identified that the taurine-binding protein (TauA) of the X. citri belongs to a different evolutionary branch from that one that described for E. coli. These differences were also noticed for components of the tau operon, including a putative new regulator. The function and mechanism of action of each protein is discussed in order to bring light for the sulfur assimilation processes and their importance for X. citri physiology. (author)

  3. The cys regulon of Xanthomonas citri

    Energy Technology Data Exchange (ETDEWEB)

    Moutran, A.; Balan, A. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil)

    2012-07-01

    Full text: In Escherichia coli, genes involved in metabolic pathway of sulfate and sulfonate compounds are clustered in a cys regulon, which includes three ABC transport system (operons: sbpcysWUA; ssuABC and tauABC), thirteen genes involved in the sulfur reduction (ssuDE; tauD and cysDNCHIJGK) and two regulatory proteins that belong to LysR transcription family: CysB and Cbl. Notably, a search and comparative analysis of these genes in the genomes of the citrus pathogen Xanthomonas citri and other phylogenetically related Xanthomonas species revealed the presence of genes involved with alkanesulfonate, sulfate ester and taurine, only in X. citri, suggesting that proteins from this regulon might be associated with pathogenicity in citrus. Using the molecular modeling associated with a system biology view, we modeled all the protein structures of the X. citri cys regulon as well as characterized the important residues forming the putative active sites. Comparison with orthologs from different microorganisms was made in order to get a phylogenetic relationships. We showed that proteins that are responsible for the affinity and specificity of the alkanesulfonate, sulfate and taurine transport systems conserved the residues involved in the sulfate coordination but are organized in different branches in evolution. Inside these phylogenetic branches, proteins involved in the sulfate transporter are highly conserved when compared to the others. Moreover, we identified that the taurine-binding protein (TauA) of the X. citri belongs to a different evolutionary branch from that one that described for E. coli. These differences were also noticed for components of the tau operon, including a putative new regulator. The function and mechanism of action of each protein is discussed in order to bring light for the sulfur assimilation processes and their importance for X. citri physiology. (author)

  4. Repellent Activity of Botanical Oils against Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae)

    OpenAIRE

    Kuhns, Emily H.; Xavier Martini; Angel Hoyte; Stelinski, Lukasz L.

    2016-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama, is the insect vector of the pathogen causing huanglongbing. We selected three botanical oils to evaluate behavioral activity against D. citri. In laboratory olfactometer assays, fir oil was repellent to D. citri females, while litsea and citronella oils elicited no response from D. citri females. In choice settling experiments, D. citri settled almost completely on control plants rather than on plants treated with fir oil at a 9.5 mg/day re...

  5. Presencia de Diaphorina citri (Hemiptera: Psyllidae en el Noroeste Argentino (NOA Record of Diaphorina citri (Hemiptera: Psyllidae in North West Argentina

    Directory of Open Access Journals (Sweden)

    Lucrecia Augier

    2006-12-01

    Full Text Available Se amplía la distribución de Diaphorina citri Kuwayama (Hemiptera: Psyllidae para el Noroeste Argentino.The distribution of Diaphorina citri Kuwayama (Hemiptera: Psyllidae is expanded to North West Argentina.

  6. Presencia de Diaphorina citri (Hemiptera: Psyllidae) en el Noroeste Argentino (NOA) Record of Diaphorina citri (Hemiptera: Psyllidae) in North West Argentina

    OpenAIRE

    Lucrecia Augier; Gerardo Gastaminza; Marcelo Lizondo; Manuel Argañaraz; Eduardo Willink

    2006-01-01

    Se amplía la distribución de Diaphorina citri Kuwayama (Hemiptera: Psyllidae) para el Noroeste Argentino.The distribution of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is expanded to North West Argentina.

  7. IgE-mediated allergy to spider mite, Panonychus citri in occupationally exposed individuals.

    Science.gov (United States)

    Ashida, T; Ide, T; Tabata, S; Kunimatsu, M; Etoh, Y; Yoshikawa, T; Matsunaga, T

    1995-11-01

    This paper is the first report on allergy caused by a spider mite, Panonychus citri. Some of fruitgrowers cultivating Citrus junos were manifested immediate allergic symptoms by farming, especially by harvest. By examining C. junos trees, we found the trees cultivated by the fruitgrowers were infested with P. citri. Twelve subjects complaining of immediate allergic symptoms were examined by intradermal test and RAST using allergen extracts prepared from P. citri and Dermatophagoides spp. In intradermal test, ten out of twelve showed a positive response to P. citri and twelve positive to D. farinae. Positive RAST to P. citri were obtained in seven of twelve. Six of them also had positive RAST to D. farinae and D. pteronyssinus. In ELISA inhibition using a serum from Case 4, the inhibition with P. citri extract reached to 92% at the highest concentration used but at the same concentration D. farinae and D. pteronyssinus extracts did not inhibit the binding of specific IgE antibodies to allergen of P. citri. In Case 7, the extracts of P. citri, D. farinae and D. pteronyssinus inhibited at the same concentration 94%, 81%, and 87%, respectively. These results lead to the following conclusions: Seven subjects positive to P. citri in intradermal test and RAST are sensitized to P. citri. P. citri has a specific allergenic determinant in addition to a common determinant with Dermatophagoides spp. PMID:8857108

  8. Coccidoxenoides perminutus parasitizing Planococcus citri on vine in Brazil

    Directory of Open Access Journals (Sweden)

    Maria Herlândia de Araújo Fernandes

    2016-07-01

    Full Text Available ABSTRACT: From those of the mealybug family, the citrus mealybug, Planococcus citriRisso, 1813 (Hemiptera: Pseudococcidae is frequently held responsible for various diseases occurring in vineyards. This is a first time report in Brazil, on the occurrence of a parasitoid controlling P. citri. In our search for the natural enemies of P. citri, bunches of grapes with the vine were collected every week for one month, in those regions where table grapes were produced, like Petrolina, Pernambuco, Brazil. In these samples, among the natural pest infestations Coccidoxenoides perminutusGirault, 1915 (Hymenoptera: Encyrtidae was the only natural enemy species reported. In this research, we attempted to study the potential of parasitism as well as the strategies that this natural agent uses in pest control.

  9. Ultraviolet irradiation mutagenesis and recombination in spiroplasma citri

    International Nuclear Information System (INIS)

    A method for obtaining and screening uv-induced mutants from Spiroplasma citri is described. Lethality response curves showed that S. citri is more sensitive to uv irradiation than are other microorganisms. The presence of a shoulder in the lethality response curve showed the existence of systems able to repair uv-induced DNA damages. Toxic-resistant mutants have been obtained. A uv fluence equal to 10 J/m2 multiplied by 2.5x103 gave the spontaneous mutation frequency. Arsenic acid- and xylitol-resistant mutants were used to investigate transfer of genetic information in S. citri. After 90 min of incubation, the recombination frequency was 5x10-5

  10. The Asian Citrus Psyllid Genome (Diaphorina citri, Hemiptera)

    OpenAIRE

    Hunter, Wayne B.; Reese, Justin; International Psyllid Genome Consortium, The

    2014-01-01

    The Asian citrus psyllid, Diaphorina citri (Hemiptera), is an important pest of citrus because it vectors bacteria responsible for huanglongbing, which is one of the most serious diseases of citrus worldwide.  The first genome draft of D. citri (DIACI_1.0) was completed in 2011 (ARS, Ft. Pierce, FL), however, gaps in the assembly prompted additional sequencing using the long run PacBio system at the Los Alamos National Lab, NM.  The revised draft genome (DIACI_1.1) was assembled using the new...

  11. The complete mitochondrial genome sequence of Diaphorina citri (Hemiptera: Psyllidae)

    Science.gov (United States)

    The first complete mitochondrial genome (mitogenome) sequence of Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), from Guangzhou, China is presented. The circular mitogenome is 14,996 bp in length with an A+T content of 74.5%, and contains 13 protein-coding genes (PCGs), 22 tRNA genes ...

  12. Insights into xanthomonas axonopodis pv. Citri biofilm through proteomics

    KAUST Repository

    Zimaro, Tamara

    2013-08-07

    Background: Xanthomonas axonopodis pv. Citri (X. a. pv. Citri) causes citrus canker that can result in defoliation and premature fruit drop with significant production losses worldwide. Biofilm formation is an important process in bacterial pathogens and several lines of evidence suggest that in X. a. pv. Citri this process is a requirement to achieve maximal virulence since it has a major role in host interactions. In this study, proteomics was used to gain further insights into the functions of biofilms. Results: In order to identify differentially expressed proteins, a comparative proteomic study using 2D difference gel electrophoresis was carried out on X. a. pv. Citri mature biofilm and planktonic cells. The biofilm proteome showed major variations in the composition of outer membrane proteins and receptor or transport proteins. Among them, several porins and TonB-dependent receptor were differentially regulated in the biofilm compared to the planktonic cells, indicating that these proteins may serve in maintaining specific membrane-associated functions including signaling and cellular homeostasis. In biofilms, UDP-glucose dehydrogenase with a major role in exopolysaccharide production and the non-fimbrial adhesin YapH involved in adherence were over-expressed, while a polynucleotide phosphorylase that was demonstrated to negatively control biofilm formation in E. coli was down-regulated. In addition, several proteins involved in protein synthesis, folding and stabilization were up-regulated in biofilms. Interestingly, some proteins related to energy production, such as ATP-synthase were down-regulated in biofilms. Moreover, a number of enzymes of the tricarboxylic acid cycle were differentially expressed. In addition, X. a. pv. Citri biofilms also showed down-regulation of several antioxidant enzymes. The respective gene expression patterns of several identified proteins in both X. a. pv. Citri mature biofilm and planktonic cells were evaluated by

  13. Complete Genome Sequence of the Largest Known Flavi-Like Virus, Diaphorina citri flavi-like virus, a Novel Virus of the Asian Citrus Psyllid, Diaphorina citri.

    Science.gov (United States)

    Matsumura, Emilyn E; Nerva, Luca; Nigg, Jared C; Falk, Bryce W; Nouri, Shahideh

    2016-09-08

    A novel flavi-like virus tentatively named Diaphorina citri flavi-like virus (DcFLV) was identified in field populations of Diaphorina citri through small RNA and transcriptome sequencing followed by reverse transcription (RT)-PCR. We report here the complete nucleotide sequence and genome organization of DcFLV, the largest flavi-like virus identified to date.

  14. Complete Genome Sequence of the Largest Known Flavi-Like Virus, Diaphorina citri flavi-like virus, a Novel Virus of the Asian Citrus Psyllid, Diaphorina citri

    Science.gov (United States)

    Matsumura, Emilyn E.; Nerva, Luca; Nigg, Jared C.; Falk, Bryce W.

    2016-01-01

    A novel flavi-like virus tentatively named Diaphorina citri flavi-like virus (DcFLV) was identified in field populations of Diaphorina citri through small RNA and transcriptome sequencing followed by reverse transcription (RT)-PCR. We report here the complete nucleotide sequence and genome organization of DcFLV, the largest flavi-like virus identified to date. PMID:27609921

  15. Complete Genome Sequence of the Largest Known Flavi-Like Virus, Diaphorina citri flavi-like virus, a Novel Virus of the Asian Citrus Psyllid, Diaphorina citri.

    Science.gov (United States)

    Matsumura, Emilyn E; Nerva, Luca; Nigg, Jared C; Falk, Bryce W; Nouri, Shahideh

    2016-01-01

    A novel flavi-like virus tentatively named Diaphorina citri flavi-like virus (DcFLV) was identified in field populations of Diaphorina citri through small RNA and transcriptome sequencing followed by reverse transcription (RT)-PCR. We report here the complete nucleotide sequence and genome organization of DcFLV, the largest flavi-like virus identified to date. PMID:27609921

  16. Complete Genome Sequence of the Largest Known Flavi-Like Virus, Diaphorina citri flavi-like virus, a Novel Virus of the Asian Citrus Psyllid, Diaphorina citri

    OpenAIRE

    Matsumura, Emilyn E.; Nerva, Luca; Nigg, Jared C.; Falk, Bryce W.; Nouri, Shahideh

    2016-01-01

    A novel flavi-like virus tentatively named Diaphorina citri flavi-like virus (DcFLV) was identified in field populations of Diaphorina citri through small RNA and transcriptome sequencing followed by reverse transcription (RT)-PCR. We report here the complete nucleotide sequence and genome organization of DcFLV, the largest flavi-like virus identified to date.

  17. Repellent Activity of Botanical Oils against Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Kuhns, Emily H; Martini, Xavier; Hoyte, Angel; Stelinski, Lukasz L

    2016-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama, is the insect vector of the pathogen causing huanglongbing. We selected three botanical oils to evaluate behavioral activity against D. citri. In laboratory olfactometer assays, fir oil was repellent to D. citri females, while litsea and citronella oils elicited no response from D. citri females. In choice settling experiments, D. citri settled almost completely on control plants rather than on plants treated with fir oil at a 9.5 mg/day release rate. Therefore, we conducted field trials to determine if fir oil reduced D. citri densities in citrus groves. We found no repellency of D. citri from sweet orange resets that were treated with fir oil dispensers releasing 10.4 g/day/tree as compared with control plots. However, we found a two-week decrease in populations of D. citri as compared with controls when the deployment rate of these dispensers was doubled. Our results suggest that treatment of citrus with fir oil may have limited activity as a stand-alone management tool for D. citri and would require integration with other management practices. PMID:27429006

  18. Repellent Activity of Botanical Oils against Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae

    Directory of Open Access Journals (Sweden)

    Emily H. Kuhns

    2016-07-01

    Full Text Available The Asian citrus psyllid, Diaphorina citri Kuwayama, is the insect vector of the pathogen causing huanglongbing. We selected three botanical oils to evaluate behavioral activity against D. citri. In laboratory olfactometer assays, fir oil was repellent to D. citri females, while litsea and citronella oils elicited no response from D. citri females. In choice settling experiments, D. citri settled almost completely on control plants rather than on plants treated with fir oil at a 9.5 mg/day release rate. Therefore, we conducted field trials to determine if fir oil reduced D. citri densities in citrus groves. We found no repellency of D. citri from sweet orange resets that were treated with fir oil dispensers releasing 10.4 g/day/tree as compared with control plots. However, we found a two-week decrease in populations of D. citri as compared with controls when the deployment rate of these dispensers was doubled. Our results suggest that treatment of citrus with fir oil may have limited activity as a stand-alone management tool for D. citri and would require integration with other management practices.

  19. Repellent Activity of Botanical Oils against Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Kuhns, Emily H; Martini, Xavier; Hoyte, Angel; Stelinski, Lukasz L

    2016-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama, is the insect vector of the pathogen causing huanglongbing. We selected three botanical oils to evaluate behavioral activity against D. citri. In laboratory olfactometer assays, fir oil was repellent to D. citri females, while litsea and citronella oils elicited no response from D. citri females. In choice settling experiments, D. citri settled almost completely on control plants rather than on plants treated with fir oil at a 9.5 mg/day release rate. Therefore, we conducted field trials to determine if fir oil reduced D. citri densities in citrus groves. We found no repellency of D. citri from sweet orange resets that were treated with fir oil dispensers releasing 10.4 g/day/tree as compared with control plots. However, we found a two-week decrease in populations of D. citri as compared with controls when the deployment rate of these dispensers was doubled. Our results suggest that treatment of citrus with fir oil may have limited activity as a stand-alone management tool for D. citri and would require integration with other management practices.

  20. Xylan utilization regulon in Xanthomonas citri pv. citri Strain 306: gene expression and utilization of oligoxylosides.

    Science.gov (United States)

    Chow, V; Shantharaj, D; Guo, Y; Nong, G; Minsavage, G V; Jones, J B; Preston, J F

    2015-03-01

    Xanthomonas citri pv. citri strain 306 (Xcc306), a causative agent of citrus canker, produces endoxylanases that catalyze the depolymerization of cell wall-associated xylans. In the sequenced genomes of all plant-pathogenic xanthomonads, genes encoding xylanolytic enzymes are clustered in three adjacent operons. In Xcc306, these consecutive operons contain genes encoding the glycoside hydrolase family 10 (GH10) endoxylanases Xyn10A and Xyn10C, the agu67 gene, encoding a GH67 α-glucuronidase (Agu67), the xyn43E gene, encoding a putative GH43 α-l-arabinofuranosidase, and the xyn43F gene, encoding a putative β-xylosidase. Recombinant Xyn10A and Xyn10C convert polymeric 4-O-methylglucuronoxylan (MeGXn) to oligoxylosides methylglucuronoxylotriose (MeGX3), xylotriose (X3), and xylobiose (X2). Xcc306 completely utilizes MeGXn predigested with Xyn10A or Xyn10C but shows little utilization of MeGXn. Xcc306 with a deletion in the gene encoding α-glucuronidase (Xcc306 Δagu67) will not utilize MeGX3 for growth, demonstrating the role of Agu67 in the complete utilization of GH10-digested MeGXn. Preferential growth on oligoxylosides compared to growth on polymeric MeGXn indicates that GH10 xylanases, either secreted by Xcc306 in planta or produced by the plant host, generate oligoxylosides that are processed by Xyn10 xylanases and Agu67 residing in the periplasm. Coordinate induction by oligoxylosides of xyn10, agu67, cirA, the tonB receptor, and other genes within these three operons indicates that they constitute a regulon that is responsive to the oligoxylosides generated by the action of Xcc306 GH10 xylanases on MeGXn. The combined expression of genes in this regulon may allow scavenging of oligoxylosides derived from cell wall deconstruction, thereby contributing to the tissue colonization and/or survival of Xcc306 and, ultimately, to plant disease. PMID:25595763

  1. Complete Genome Sequence of a Putative Densovirus of the Asian Citrus Psyllid, Diaphorina citri.

    Science.gov (United States)

    Nigg, Jared C; Nouri, Shahideh; Falk, Bryce W

    2016-07-28

    Here, we report the complete genome sequence of a putative densovirus of the Asian citrus psyllid, Diaphorina citri Diaphorina citri densovirus (DcDNV) was originally identified through metagenomics, and here, we obtained the complete nucleotide sequence using PCR-based approaches. Phylogenetic analysis places DcDNV between viruses of the Ambidensovirus and Iteradensovirus genera.

  2. Complete Genome Sequence of a Putative Densovirus of the Asian Citrus Psyllid, Diaphorina citri.

    Science.gov (United States)

    Nigg, Jared C; Nouri, Shahideh; Falk, Bryce W

    2016-01-01

    Here, we report the complete genome sequence of a putative densovirus of the Asian citrus psyllid, Diaphorina citri Diaphorina citri densovirus (DcDNV) was originally identified through metagenomics, and here, we obtained the complete nucleotide sequence using PCR-based approaches. Phylogenetic analysis places DcDNV between viruses of the Ambidensovirus and Iteradensovirus genera. PMID:27469948

  3. First report of citrus canker caused by Xanthomonas citri in Somalia

    Science.gov (United States)

    Xanthomonas citri, causal agent of citrus canker, has been reported in several countries in Africa, but not Somalia. During 2006 and 2007, hyperplasia-type lesions, often surrounded by a water-soaked margin and yellow halo, typical of citrus canker caused by X. citri, were found on 8-10 year-old gr...

  4. Complete Genome Sequence of a Putative Densovirus of the Asian Citrus Psyllid, Diaphorina citri

    OpenAIRE

    Nigg, Jared C.; Nouri, Shahideh; Falk, Bryce W.

    2016-01-01

    Here, we report the complete genome sequence of a putative densovirus of the Asian citrus psyllid, Diaphorina citri. Diaphorina citri densovirus (DcDNV) was originally identified through metagenomics, and here, we obtained the complete nucleotide sequence using PCR-based approaches. Phylogenetic analysis places DcDNV between viruses of the Ambidensovirus and Iteradensovirus genera.

  5. Diaphorina citri (Hemiptera: Liviidae) Vector Competence for the Citrus Greening Pathogen 'Candidatus Liberibacter Asiaticus'.

    Science.gov (United States)

    Tabachnick, Walter J

    2015-06-01

    Characterizing the vector competence of Diaphorina citri Kuwayama for 'Candidatus Liberibacter asiaticus,' the pathogen causing citrus greening, is essential for understanding the epidemiology of this disease that is threatening the U.S. citrus industry. Vector competence studies have been difficult because of the biology of D. citri, the inability to culture the pathogen, and the available diagnostic methods used to detect the bacteria in plant and insect tissues. The methods employed in many studies of D. citri vector competence may have overestimated amounts of live 'Ca. L. asiaticus' in both plant and insect tissues, and it is possible that the amounts of phloem ingested by psyllids may not contain sufficient detectable pathogen using current diagnostic methods. As a result of the difficulty in characterizing D. citri vector competence, the several daunting challenges for providing D. citri that are unable to inoculate 'Ca. L. asiaticus', as a novel method to control greening are discussed. Suggestions to overcome some of these challenges are provided.

  6. Complete Genome Sequence of Diaphorina citri-associated C virus, a Novel Putative RNA Virus of the Asian Citrus Psyllid, Diaphorina citri.

    Science.gov (United States)

    Nouri, Shahideh; Salem, Nidà; Falk, Bryce W

    2016-07-21

    We present here the complete nucleotide sequence and genome organization of a novel putative RNA virus identified in field populations of the Asian citrus psyllid, Diaphorina citri, through sequencing of the transcriptome followed by reverse transcription-PCR (RT-PCR). We tentatively named this virus Diaphorina citri-associated C virus (DcACV). DcACV is an unclassified positive-sense RNA virus.

  7. Complete Genome Sequence of Diaphorina citri-associated C virus, a Novel Putative RNA Virus of the Asian Citrus Psyllid, Diaphorina citri

    Science.gov (United States)

    Nouri, Shahideh; Salem, Nidà

    2016-01-01

    We present here the complete nucleotide sequence and genome organization of a novel putative RNA virus identified in field populations of the Asian citrus psyllid, Diaphorina citri, through sequencing of the transcriptome followed by reverse transcription-PCR (RT-PCR). We tentatively named this virus Diaphorina citri-associated C virus (DcACV). DcACV is an unclassified positive-sense RNA virus. PMID:27445370

  8. Complete Genome Sequence of Diaphorina citri-associated C virus, a Novel Putative RNA Virus of the Asian Citrus Psyllid, Diaphorina citri.

    Science.gov (United States)

    Nouri, Shahideh; Salem, Nidà; Falk, Bryce W

    2016-01-01

    We present here the complete nucleotide sequence and genome organization of a novel putative RNA virus identified in field populations of the Asian citrus psyllid, Diaphorina citri, through sequencing of the transcriptome followed by reverse transcription-PCR (RT-PCR). We tentatively named this virus Diaphorina citri-associated C virus (DcACV). DcACV is an unclassified positive-sense RNA virus. PMID:27445370

  9. Complete Genome Sequence of Diaphorina citri-associated C virus, a Novel Putative RNA Virus of the Asian Citrus Psyllid, Diaphorina citri

    OpenAIRE

    Nouri, Shahideh; Salem, Nidà; Falk, Bryce W.

    2016-01-01

    We present here the complete nucleotide sequence and genome organization of a novel putative RNA virus identified in field populations of the Asian citrus psyllid, Diaphorina citri, through sequencing of the transcriptome followed by reverse transcription-PCR (RT-PCR). We tentatively named this virus Diaphorina citri-associated C virus (DcACV). DcACV is an unclassified positive-sense RNA virus.

  10. Inter-Population Variability of Endosymbiont Densities in the Asian Citrus Psyllid (Diaphorina citri Kuwayama).

    Science.gov (United States)

    Chu, Chia-Ching; Gill, Torrence A; Hoffmann, Mark; Pelz-Stelinski, Kirsten S

    2016-05-01

    The Asian citrus psyllid (Diaphorina citri Kuwayama) is an insect pest capable of transmitting Candidatus Liberibacter asiaticus (CLas), the causal agent of citrus greening in North America. D. citri also harbors three endosymbionts, Wolbachia, Candidatus Carsonella ruddii, and Candidatus Profftella armatura, which may influence D. citri physiology and fitness. Although genomic researches on these bacteria have been conducted, much remains unclear regarding their ecology and inter-population variability in D. citri. The present work examined the densities of each endosymbiont in adult D. citri sampled from different populations using quantitative PCR. Under field conditions, the densities of all three endosymbionts positively correlated with each other, and they are associated with D. citri gender and locality. In addition, the infection density of CLas also varied across populations. Although an analysis pooling D. citri from different populations showed that CLas-infected individuals tended to have lower endosymbiont densities compared to uninfected individuals, the difference was not significant when the population was included as a factor in the analysis, suggesting that other population-specific factors may have stronger effects on endosymbiont densities. To determine whether there is a genetic basis to the density differences, endosymbiont densities between aged CLas-negative females of two D. citri populations reared under standardized laboratory conditions were compared. Results suggested that inter-population variability in Wolbachia infection density is associated with the genotypes of the endosymbiont or the host. Findings from this work could facilitate understanding of D. citri-bacterial associations that may benefit the development of approaches for managing citrus greening, such as prevention of CLas transmission. PMID:26846216

  11. Inter-Population Variability of Endosymbiont Densities in the Asian Citrus Psyllid (Diaphorina citri Kuwayama).

    Science.gov (United States)

    Chu, Chia-Ching; Gill, Torrence A; Hoffmann, Mark; Pelz-Stelinski, Kirsten S

    2016-05-01

    The Asian citrus psyllid (Diaphorina citri Kuwayama) is an insect pest capable of transmitting Candidatus Liberibacter asiaticus (CLas), the causal agent of citrus greening in North America. D. citri also harbors three endosymbionts, Wolbachia, Candidatus Carsonella ruddii, and Candidatus Profftella armatura, which may influence D. citri physiology and fitness. Although genomic researches on these bacteria have been conducted, much remains unclear regarding their ecology and inter-population variability in D. citri. The present work examined the densities of each endosymbiont in adult D. citri sampled from different populations using quantitative PCR. Under field conditions, the densities of all three endosymbionts positively correlated with each other, and they are associated with D. citri gender and locality. In addition, the infection density of CLas also varied across populations. Although an analysis pooling D. citri from different populations showed that CLas-infected individuals tended to have lower endosymbiont densities compared to uninfected individuals, the difference was not significant when the population was included as a factor in the analysis, suggesting that other population-specific factors may have stronger effects on endosymbiont densities. To determine whether there is a genetic basis to the density differences, endosymbiont densities between aged CLas-negative females of two D. citri populations reared under standardized laboratory conditions were compared. Results suggested that inter-population variability in Wolbachia infection density is associated with the genotypes of the endosymbiont or the host. Findings from this work could facilitate understanding of D. citri-bacterial associations that may benefit the development of approaches for managing citrus greening, such as prevention of CLas transmission.

  12. Acaricidal Activity of Boenninghausenia sessilicarpa Against Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    YANG Hui-zhi; HU Jun-hua; LI Qing; LI Hong-jun; LIU Hao-qiang; YAO Ting-shan; RAN Chun; LEI Hui-de

    2009-01-01

    Acaricidal activity of Boenninghausenia sessilicarpa against Panonychus citri was tested in the laboratory.Four solvents were used to prepare crude extracts,petroleum ether,chloroform,ethyl acetate,and ethanol,among which ethanol was the most effective one.The results suggested that ethanol extracts of B.sessilicarpa had eminent acaricidal and ovicidal activities.Concentrated extracts were prepared using petroleum ether,chloroform,ethyl acetate,or distilled water as solvent.Mite mortality rates in the concentrated extracts by petroleum ether,chloroform,or distilled water were significantly lower than those by ethyl acetate.The LC50 values of eggs and female mites were 0.7639 and 1.1033 mg mL-1,respectively.After liquid chromatography and thin layer chromatography,the concentrated extracts were separated into 14 groups of fractions and further tests for their acaricidal and ovicidal activities were conducted.Fraction 2 was found to possess higher acaricidal and ovicidal activities.The mortality of eggs and adult mites were 85.83 and 63.07%,respectively.Moreover,fraction 2 showed moderate oviposition inhibition effect (0.8795) against P.citri when the used dose Was higher than 2.5 mg mL-1.

  13. Control of the Chinese citrus fly, Dacus citri (Chen), using the sterile insect technique

    International Nuclear Information System (INIS)

    Artificial rearing of the Chinese citrus fly, Dacus citri (Chen), is described. It was found that the appropriate irradiation stage for sterilization treatment is at the last pupal phase, one or two days before emergence, and that 9 krad of irradiation is a suitable dose for sterilizing D. citri. A total of 56,000 and 95,000 irradiated sterile males of D. citri were released in the Zhonglian orchard (about 34 ha) in Huishui County, Guizhou Province, in 1987 and 1989, respectively. The release ratio of sterile to native fruit flies was 12.5:1 and 45:1. The percentage of oranges damaged by D. citri dropped from 7.5 to 0.005. (author). 5 refs, 4 tabs

  14. Chemical features of Pericarpium Citri Reticulatae and Pericarpium Citri Reticulatae Viride revealed by GC-MS metabolomics analysis.

    Science.gov (United States)

    Yi, Lunzhao; Dong, Naiping; Liu, Shao; Yi, Zhibiao; Zhang, Yi

    2015-11-01

    This paper introduces a detailed method to apply metabolic profiles conducting on tangerine peels (Citrus reticulata 'Dahongpao') at three maturity stages from July to December. Principal component analysis not only demonstrated the metabolic footprints of tangerine peels during ripening but also revealed the compounds (D-limonene and linalool) that mostly contributed to it. Furthermore, some other characteristic compounds were screened to further reveal the chemical features of Pericarpium Citri Reticulatae (PCR) and Pericarpium Citri Reticulatae Viride (PCRV). In particular, compounds such as 4-carene (r = -0.94), 3-carene (r = -0.91), β-pinene (r = -0.85) and γ-terpinene (r = -0.87) were screened as major components for the pungent smell of PCRV. Geranyl acetate (r = 0.81), farnesyl acetate (r = 0.87) and three alcohols (6-hepten-1-ol, 3-methyl-1-hexanol, 1-octanol) may lead to the pleasant odour of PCR. We therefore propose that the metabolomics analysis focusing on ripening process will be an effective strategy for quality control of closely related herbal medicines. PMID:25976810

  15. The role as inoculum sources of Xanthomonas citri pv. citri surviving on the infected Satsuma mandarin fruits.

    Science.gov (United States)

    Kang, So Young; Kim, Ki Deok; Hong, Jeum Kyu; Hyun, He Nam; Jeun, Yong Chull

    2014-05-01

    Importing citrus fruits infected by Asiatic citrus canker caused by Xanthomonas citri pv. citri (Xcc) can act as an inoculum source for the disease epidemic in citrus canker-free countries. In this study, the pathogenicity of the causal agent of Asiatic citrus canker surviving on infected Satsuma mandarin fruits was evaluated. The washing solution of infected Satsuma mandarin fruits did not cause lesion formation on the citrus leaves. However, a typical citrus canker lesion was formed on the leaves after inoculation with higher concentrations of the inoculum from the washing solution (washing solution II). It indicated that the pathogenicity of the citrus canker surviving on the symptomatic Satsuma mandarin fruits was not changed. Scanning electron microscopic observation showed that the numbers of bacterial cells on the leaves of Satsuma mandarin which inoculated with the washing solution directly (washing solution I) was less compared to those of leaves inoculated with the washing solution II. This result spports that the pathogenicity of Xcc surviving on Satsuma mandarin fruits may not be changed but that the sucessful infection of citrus caker may depend on the concentration of the inoculum.

  16. Dispersion patterns and sampling plans for Diaphorina citri (Hemiptera: Psyllidae) in citrus.

    Science.gov (United States)

    Sétamou, Mamoudou; Flores, Daniel; French, J Victor; Hall, David G

    2008-08-01

    The abundance and spatial dispersion of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) were studied in 34 grapefruit (Citrus paradisi Macfad.) and six sweet orange [Citrus sinensis (L.) Osbeck] orchards from March to August 2006 when the pest is more abundant in southern Texas. Although flush shoot infestation levels did not vary with host plant species, densities of D. citri eggs, nymphs, and adults were significantly higher on sweet orange than on grapefruit. D. citri immatures also were found in significantly higher numbers in the southeastern quadrant of trees than other parts of the canopy. The spatial distribution of D. citri nymphs and adults was analyzed using Iowa's patchiness regression and Taylor's power law. Taylor's power law fitted the data better than Iowa's model. Based on both regression models, the field dispersion patterns of D. citri nymphs and adults were aggregated among flush shoots in individual trees as indicated by the regression slopes that were significantly >1. For the average density of each life stage obtained during our surveys, the minimum number of flush shoots per tree needed to estimate D. citri densities varied from eight for eggs to four flush shoots for adults. Projections indicated that a sampling plan consisting of 10 trees and eight flush shoots per tree would provide density estimates of the three developmental stages of D. citri acceptable enough for population studies and management decisions. A presence-absence sampling plan with a fixed precision level was developed and can be used to provide a quick estimation of D. citri populations in citrus orchards.

  17. Molecular Effects of Irradiation (Cobalt-60) on the Control of Panonychus citri (Acari: Tetranychidae)

    OpenAIRE

    Ke Zhang; Lingyan Luo; Xieting Chen; Meiying Hu; Qiongbo Hu; Liang Gong; Qunfang Weng

    2015-01-01

    The effective dose of irradiation to control pest mites in quarantine has been studied extensively, but the molecular mechanisms underlying the effects of the irradiation on mites are largely unknown. In this study, exposure to 400 Gy of γ rays had significant (p < 0.05) effects on the adult survival, fecundity and egg viability of Panonychus citri. The irradiation caused the degradation of the DNA of P. citri adults and damaged the plasma membrane system of the egg, which led to condensed...

  18. Survey of Endosymbionts in the Diaphorina citri Metagenome and Assembly of a Wolbachia wDi Draft Genome

    OpenAIRE

    Surya Saha; Hunter, Wayne B.; Justin Reese; J Kent Morgan; Mizuri Marutani-Hert; Hong Huang; Magdalen Lindeberg

    2012-01-01

    Diaphorina citri (Hemiptera: Psyllidae), the Asian citrus psyllid, is the insect vector of Ca. Liberibacter asiaticus, the causal agent of citrus greening disease. Sequencing of the D. citri metagenome has been initiated to gain better understanding of the biology of this organism and the potential roles of its bacterial endosymbionts. To corroborate candidate endosymbionts previously identified by rDNA amplification, raw reads from the D. citri metagenome sequence were mapped to reference ge...

  19. Within-orchard edge effects of the azimuth of the sun on Diaphorina citri adults in mature orchards.

    OpenAIRE

    Anco, D J; Gottwald, T. R.

    2015-01-01

    Huanglongbing (HLB) is considered the most devastating disease of citrus. The bacterium and vector associated with HLB in Florida are Candidatus Liberibacter asiaticus and Diaphorina citri (Asian citrus psyllid), respectively. D. citri is positively phototropic, and higher populations have been found along edges of orchards exposed to the sun. A survey was designed to determine if D. citri adult populations along edges of orchards varied according to time-of-day and time-of-year in relation t...

  20. Population ecology and phenology of Diaphorina citri (Hemiptera: Psyllidae) in two Florida citrus groves.

    Science.gov (United States)

    Hall, David G; Hentz, Matthew G; Adair, Robert C

    2008-08-01

    Studies were conducted to assess population densities and phenology of the psyllid Diaphorina citri Kuwayama at two citrus groves in east-central Florida. One grove contained young, irrigated grapefruit trees and the other contained mature, nonirrigated orange trees. The two groves were sampled weekly for eggs, nymphs, and adults on flush shoots; for adults on mature leaves; and for adults captured on yellow sticky card traps. Because infestations of immature D. citri develop strictly on young flush, the abundance of flush was assessed weekly. Overall means of 26.5, 16.8, and 0.27 eggs, nymphs, and adults per flush shoot, respectively, were observed in the young grapefruit trees. In the grove of mature orange trees, overall means of 16.0, 12.7, and 0.31 eggs, nymphs, and adults per flush shoot were observed, respectively. Flush abundance was an inconsistent indicator of the mean density of D. citri per flush shoot. Mean density per shoot by itself was an inconsistent indicator of overall population levels of D. citri at each study site because few shoots were sometimes present when mean densities per shoot were high. May, June, and July were periods of time when immature D. citri were consistently present and most abundant at each study site, but the study indicated large infestations could occur at any time of the year depending on environmental factors and flush availability. Yellow sticky traps were effective for both male and female D. citri and useful for gauging adult population trends.

  1. Use of recombinant tobacco mosaic virus to achieve RNA interference in plants against the citrus mealybug, Planococcus citri (Hemiptera: Pseudococcidae.

    Directory of Open Access Journals (Sweden)

    Arif Muhammad Khan

    Full Text Available The citrus mealybug, Planococcus citri, is an important plant pest with a very broad plant host range. P. citri is a phloem feeder and loss of plant vigor and stunting are characteristic symptoms induced on a range of host plants, but P. citri also reduces fruit quality and causes fruit drop leading to significant yield reductions. Better strategies for managing this pest are greatly needed. RNA interference (RNAi is an emerging tool for functional genomics studies and is being investigated as a practical tool for highly targeted insect control. Here we investigated whether RNAi effects can be induced in P. citri and whether candidate mRNAs could be identified as possible targets for RNAi-based P. citri control. RNAi effects were induced in P. citri, as demonstrated by specific target reductions of P. citri actin, chitin synthase 1 and V-ATPase mRNAs after injection of the corresponding specific double-stranded RNA inducers. We also used recombinant Tobacco mosaic virus (TMV to express these RNAi effectors in Nicotiana benthamiana plants. We found that P. citri showed lower fecundity and pronounced death of crawlers after feeding on recombinant TMV-infected plants. Taken together, our data show that actin, chitin synthase 1 and V-ATPase mRNAs are potential targets for RNAi against P. citri, and that recombinant TMV is an effective tool for evaluating candidate RNAi effectors in plants.

  2. Use of recombinant tobacco mosaic virus to achieve RNA interference in plants against the citrus mealybug, Planococcus citri (Hemiptera: Pseudococcidae).

    Science.gov (United States)

    Khan, Arif Muhammad; Ashfaq, Muhammad; Kiss, Zsofia; Khan, Azhar Abbas; Mansoor, Shahid; Falk, Bryce W

    2013-01-01

    The citrus mealybug, Planococcus citri, is an important plant pest with a very broad plant host range. P. citri is a phloem feeder and loss of plant vigor and stunting are characteristic symptoms induced on a range of host plants, but P. citri also reduces fruit quality and causes fruit drop leading to significant yield reductions. Better strategies for managing this pest are greatly needed. RNA interference (RNAi) is an emerging tool for functional genomics studies and is being investigated as a practical tool for highly targeted insect control. Here we investigated whether RNAi effects can be induced in P. citri and whether candidate mRNAs could be identified as possible targets for RNAi-based P. citri control. RNAi effects were induced in P. citri, as demonstrated by specific target reductions of P. citri actin, chitin synthase 1 and V-ATPase mRNAs after injection of the corresponding specific double-stranded RNA inducers. We also used recombinant Tobacco mosaic virus (TMV) to express these RNAi effectors in Nicotiana benthamiana plants. We found that P. citri showed lower fecundity and pronounced death of crawlers after feeding on recombinant TMV-infected plants. Taken together, our data show that actin, chitin synthase 1 and V-ATPase mRNAs are potential targets for RNAi against P. citri, and that recombinant TMV is an effective tool for evaluating candidate RNAi effectors in plants.

  3. A survey of FLS2 genes from multiple citrus species identifies candidates for enhancing disease resistance to Xanthomonas citri ssp. citri.

    OpenAIRE

    Qingchun Shi; Febres, Vicente J.; Jones, Jeffrey B; MOORE, Gloria A.

    2016-01-01

    Pathogen-associated molecular patterns (PAMPs)-triggered immunity (PTI) is an important component of plant innate immunity. In a previous study, we showed that the PAMP flg22 from Xanthomonas citri ssp. citri (Xflg22), the causal agent of citrus canker, induced PTI in citrus, which correlated with the observed levels of canker resistance. Here, we identified and sequenced two bacterial flagellin/flg22 receptors (FLS2-1 and FLS2-2) from ‘Duncan’ grapefruit (Citrus paradisi, CpFLS2-1 and CpFLS2...

  4. Chemotactic signal transduction and phosphate metabolism as adaptive strategies during citrus canker induction by Xanthomonas citri.

    Science.gov (United States)

    Moreira, Leandro Marcio; Facincani, Agda Paula; Ferreira, Cristiano Barbalho; Ferreira, Rafael Marine; Ferro, Maria Inês Tiraboshi; Gozzo, Fabio Cesar; de Oliveira, Julio Cezar Franco; Ferro, Jesus Aparecido; Soares, Márcia Regina

    2015-03-01

    The genome of Xanthomonas citri subsp. Citri strain 306 pathotype A (Xac) was completely sequenced more than 10 years; to date, few studies involving functional genomics Xac and its host compatible have been developed, specially related to adaptive events that allow the survival of Xac within the plant. Proteomic analysis of Xac showed that the processes of chemotactic signal transduction and phosphate metabolism are key adaptive strategies during the interaction of a pathogenic bacterium with its plant host. The results also indicate the importance of a group of proteins that may not be directly related to the classical virulence factors, but that are likely fundamental to the success of the initial stages of the infection, such as methyl-accepting chemotaxis protein (Mcp) and phosphate specific transport (Pst). Furthermore, the analysis of the mutant of the gene pstB which codifies to an ABC phosphate transporter subunit revealed a complete absence of citrus canker symptoms when inoculated in compatible hosts. We also conducted an in silico analysis which established the possible network of genes regulated by two-component systems PhoPQ and PhoBR (related to phosphate metabolism), and possible transcriptional factor binding site (TFBS) motifs of regulatory proteins PhoB and PhoP, detaching high degree of conservation of PhoB TFBS in 84 genes of Xac genome. This is the first time that chemotaxis signal transduction and phosphate metabolism were therefore indicated to be fundamental to the process of colonization of plant tissue during the induction of disease associated with Xanthomonas genus bacteria. PMID:25403594

  5. Chemotactic signal transduction and phosphate metabolism as adaptive strategies during citrus canker induction by Xanthomonas citri.

    Science.gov (United States)

    Moreira, Leandro Marcio; Facincani, Agda Paula; Ferreira, Cristiano Barbalho; Ferreira, Rafael Marine; Ferro, Maria Inês Tiraboshi; Gozzo, Fabio Cesar; de Oliveira, Julio Cezar Franco; Ferro, Jesus Aparecido; Soares, Márcia Regina

    2015-03-01

    The genome of Xanthomonas citri subsp. Citri strain 306 pathotype A (Xac) was completely sequenced more than 10 years; to date, few studies involving functional genomics Xac and its host compatible have been developed, specially related to adaptive events that allow the survival of Xac within the plant. Proteomic analysis of Xac showed that the processes of chemotactic signal transduction and phosphate metabolism are key adaptive strategies during the interaction of a pathogenic bacterium with its plant host. The results also indicate the importance of a group of proteins that may not be directly related to the classical virulence factors, but that are likely fundamental to the success of the initial stages of the infection, such as methyl-accepting chemotaxis protein (Mcp) and phosphate specific transport (Pst). Furthermore, the analysis of the mutant of the gene pstB which codifies to an ABC phosphate transporter subunit revealed a complete absence of citrus canker symptoms when inoculated in compatible hosts. We also conducted an in silico analysis which established the possible network of genes regulated by two-component systems PhoPQ and PhoBR (related to phosphate metabolism), and possible transcriptional factor binding site (TFBS) motifs of regulatory proteins PhoB and PhoP, detaching high degree of conservation of PhoB TFBS in 84 genes of Xac genome. This is the first time that chemotaxis signal transduction and phosphate metabolism were therefore indicated to be fundamental to the process of colonization of plant tissue during the induction of disease associated with Xanthomonas genus bacteria.

  6. Temperature studies with the Asian citrus psyllid, Diaphorina citri: cold hardiness and temperature thresholds for oviposition.

    Science.gov (United States)

    Hall, David G; Wenninger, Erik J; Hentz, Matthew G

    2011-01-01

    This study was conducted to obtain information on the cold hardiness of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), in Florida and to assess upper and lower temperature thresholds for oviposition. The psyllid is an important pest in citrus because it transmits the bacterial pathogens responsible for citrus greening disease, Huanglongbing, considered the most serious citrus disease worldwide. D. citri was first found in Florida during 1998, and the disease was discovered during 2005. Little was known regarding cold hardiness of D. citri, but Florida citrus is occasionally subjected to notable freeze events. Temperature and duration were each significant sources of variation in percent mortality of D. citri subjected to freeze events. Relatively large percentages of adults and nymphs survived after being exposed for several hours to temperatures as low as -5 to -6 °C. Relatively large percentages of eggs hatched after being exposed for several hours to temperatures as low as -8 °C. Research results indicated that adult D. citri become cold acclimated during the winter through exposure to cooler winter temperatures. There was no evidence that eggs became cold acclimated during winter. Cold acclimation in nymphs was not investigated. Research with adult D. citri from laboratory and greenhouse colonies revealed that mild to moderate freeze events were usually nonlethal to the D. citri irrespective of whether they were cold acclimated or not. Upper and lower temperature thresholds for oviposition were investigated because such information may be valuable in explaining the geographic distribution and potential spread of the pest from Florida as well as how cooler winter temperatures might limit population growth. The estimated lower and upper thresholds for oviposition were 16.0 and 41.6 °C, respectively; the estimated temperature of peak oviposition over a 48 h period was 29.6 °C.

  7. [Analysis on medication rules of state medical master Yan Zhenghua from prescriptions with citri reticulatae pericarpium based on data mining].

    Science.gov (United States)

    Wu, Jia-Rui; Guo, Wei-Xian; Zhang, Bing; Zhang, Xiao-Meng; Yang, Bing; Sheng, Xiao-Guang

    2014-02-01

    The prescriptions containing pericarpium citri reticulatae that built by Professor. Yan were collected to build a database based on traditional Chinese medicine (TCM) inheritance assist system. After analyzed by data mining, such as apriori algorithm, the frequency of single medicine, the frequency of drug combination, the association rules between drugs and core drug combinations can be get from the database. Through the analysis of 1 027 prescriptions with pericarpium citri reticulatae, these prescriptions were commonly used to treat stomach aches, cough and other syndromes. The most frequency drug combinations were "Citri Reticulatae Pericarpium-Poria", "Paeoniae Radix Rubra-Citri Reticulatae Pericarpium" and so on. The drug association rules that the confidence was 1 were "Glycyrrhizae Radix ex Rhizoma --> Citri Reticulatae Pericarpium", "Paeoniae Alba Radix-Cyperi Rhizoma --> Citri Reticulatae Pericarpium", "Poria --> Citri Reticulatae Pericarpium", and so on. The drugs in the prescriptions containing pericarpium citri reticulatae that built by Professor Yan mostly had the effects of regulating the flow of Qi and invigorate blood circulation, which reflected the clearly thought when making prescriptions.

  8. Living on the Edges: Spatial Niche Occupation of Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), in Citrus Groves.

    Science.gov (United States)

    Sétamou, Mamoudou; Bartels, David W

    2015-01-01

    The spatial niche occupation of the Asian citrus psyllid, Diaphorina citri Kuwayama, 1908, was evaluated to determine its field colonization and food resource exploitation strategies in citrus groves. Mature grapefruit and sweet orange groves were surveyed as part of an area-wide program in 2009-2010 to determine D. citri population densities and between-tree distribution. In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a strong edge effect in D. citri distribution in the groves. D. citri densities and infestation levels gradually declined from the edge to the center of grove. Higher numbers of D. citri were recorded on trees located on the east and south sides of the groves than those on the west and north sides. Citrus groves located at the outer edge of the study with at least one side non-surrounded to other citrus groves harbored significantly more D. citri than groves located within the block cluster and entirely surrounded by other groves. In detailed field studies during 2012, infestation of D. citri started from border trees in the grove where possibly one generation is completed before inner trees become infested. In addition, psyllid densities decreased significantly with increasing distance from the grove edge. Using the selection index, D citri exhibited a strong niche occupation preference for border trees. PMID:26193111

  9. Within-orchard edge effects of the azimuth of the sun on Diaphorina citri adults in mature orchards

    Science.gov (United States)

    Huanglongbing (HLB) has been considered the most devastating disease of citrus. The bacterium and vector associated with HLB in Florida are ‘Candidatus Liberibacter asiaticus’ and Diaphorina citri (Asian citrus psyllid), respectively. D. citri is positively phototropic, and higher populations have b...

  10. Living on the Edges: Spatial Niche Occupation of Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), in Citrus Groves.

    Science.gov (United States)

    Sétamou, Mamoudou; Bartels, David W

    2015-01-01

    The spatial niche occupation of the Asian citrus psyllid, Diaphorina citri Kuwayama, 1908, was evaluated to determine its field colonization and food resource exploitation strategies in citrus groves. Mature grapefruit and sweet orange groves were surveyed as part of an area-wide program in 2009-2010 to determine D. citri population densities and between-tree distribution. In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a strong edge effect in D. citri distribution in the groves. D. citri densities and infestation levels gradually declined from the edge to the center of grove. Higher numbers of D. citri were recorded on trees located on the east and south sides of the groves than those on the west and north sides. Citrus groves located at the outer edge of the study with at least one side non-surrounded to other citrus groves harbored significantly more D. citri than groves located within the block cluster and entirely surrounded by other groves. In detailed field studies during 2012, infestation of D. citri started from border trees in the grove where possibly one generation is completed before inner trees become infested. In addition, psyllid densities decreased significantly with increasing distance from the grove edge. Using the selection index, D citri exhibited a strong niche occupation preference for border trees.

  11. Living on the Edges: Spatial Niche Occupation of Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae, in Citrus Groves.

    Directory of Open Access Journals (Sweden)

    Mamoudou Sétamou

    Full Text Available The spatial niche occupation of the Asian citrus psyllid, Diaphorina citri Kuwayama, 1908, was evaluated to determine its field colonization and food resource exploitation strategies in citrus groves. Mature grapefruit and sweet orange groves were surveyed as part of an area-wide program in 2009-2010 to determine D. citri population densities and between-tree distribution. In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a strong edge effect in D. citri distribution in the groves. D. citri densities and infestation levels gradually declined from the edge to the center of grove. Higher numbers of D. citri were recorded on trees located on the east and south sides of the groves than those on the west and north sides. Citrus groves located at the outer edge of the study with at least one side non-surrounded to other citrus groves harbored significantly more D. citri than groves located within the block cluster and entirely surrounded by other groves. In detailed field studies during 2012, infestation of D. citri started from border trees in the grove where possibly one generation is completed before inner trees become infested. In addition, psyllid densities decreased significantly with increasing distance from the grove edge. Using the selection index, D citri exhibited a strong niche occupation preference for border trees.

  12. Transmission of different strains of Spiroplasma citri to carrot and citrus by Circulifer tenellus Baker (Hemiptera:Cicadellidae)

    Science.gov (United States)

    Carrot purple leaf disease (CPLD) was associated with the presence of Spiroplasma citri in 2006 in the state of Washington, USA (Lee et al. 2006). The objectives of this work were to (1) confirm S. citri as the causal agent of CPLD by fulfilling Koch’s postulates, (2) to determine whether carrot str...

  13. Chemical and behavioral analysis of the cuticular hydrocarbons from Asian citrus psyllid, Diaphorina citri.

    Science.gov (United States)

    Mann, Rajinder S; Rouseff, Russell L; Smoot, Jack; Rao, Nandikeswara; Meyer, Wendy L; Lapointe, Stephen L; Robbins, Paul S; Cha, Dong; Linn, Charles E; Webster, Francis X; Tiwari, Siddharth; Stelinski, Lukasz L

    2013-06-01

    Huanglongbing (HLB) is the most destructive disease of citrus worldwide. The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the vector of the phloem-inhabiting bacterium, Candidatus Liberibacter asiaticus, which is presumed to cause HLB in Florida citrus. Laboratory and field studies were conducted to examine the behavioral responses of male and female D. citri to their cuticular extracts. In olfactometer assays, more male D. citri were attracted to one, five, or 10 female cuticular extract equivalent units than blank controls. The results were confirmed in field studies in which clear or yellow traps baited with 10 female cuticular extract equivalent units attracted proportionately more males than clear traps baited with male cuticular extract or unbaited traps. Analyses of cuticular constituents of male and female D. citri revealed differences between the sexes in chemical composition of their cuticular extracts. Laboratory bioassays with synthetic chemicals identified from cuticular extracts indicated that dodecanoic acid attracted more males than clean air. Traps baited with dodecanoic acid did not increase total catch of D. citri as compared with blank traps at the dosages tested; however, the sex ratio of psyllid catch was male biased on traps baited with the highest lure loading dosage tested (10.0 mg). PMID:23955888

  14. Diaphorina citri (Hemiptera: Liviidae) Vector Competence for the Citrus Greening Pathogen 'Candidatus Liberibacter Asiaticus'.

    Science.gov (United States)

    Tabachnick, Walter J

    2015-06-01

    Characterizing the vector competence of Diaphorina citri Kuwayama for 'Candidatus Liberibacter asiaticus,' the pathogen causing citrus greening, is essential for understanding the epidemiology of this disease that is threatening the U.S. citrus industry. Vector competence studies have been difficult because of the biology of D. citri, the inability to culture the pathogen, and the available diagnostic methods used to detect the bacteria in plant and insect tissues. The methods employed in many studies of D. citri vector competence may have overestimated amounts of live 'Ca. L. asiaticus' in both plant and insect tissues, and it is possible that the amounts of phloem ingested by psyllids may not contain sufficient detectable pathogen using current diagnostic methods. As a result of the difficulty in characterizing D. citri vector competence, the several daunting challenges for providing D. citri that are unable to inoculate 'Ca. L. asiaticus', as a novel method to control greening are discussed. Suggestions to overcome some of these challenges are provided. PMID:26470202

  15. Effect of sucrose octanoate on survival of nymphal and adult Diaphorina citri (Homoptera: Psyllidae).

    Science.gov (United States)

    McKenzie, C L; Puterka, Gary J

    2004-06-01

    Asian citrus psylla, Diaphorina citri Kuwayama (Homoptera: Psyllidae) was detected for the first time in the United States near Delray Beach, FL, on 2 June 1998 and is continuing to spread and multiply throughout southern Florida. This psyllid is the vector of Liberobacter asiaticum, a phloem-limited bacterium that causes citrus greening disease. This pathogen has not been found in the Western Hemisphere to date. Furthermore, high infestation levels of D. citri can impact citrus plant health, fruit quality, or yield. Replicated laboratory and spray booth bioassays were conducted to determine the insecticidal activity of a synthetic analog of natural sugar esters found in leaf trichomes of wild tobacco, Nicotiatna gossei Domin, to nymphal and adult D. citri. Field trials were initiated in Fort Pierce, FL, in 2000 to determine activity of the sugar ester formulation (sucrose octanoate) on D. citri and other citrus pests, including immature Asian citrus leafminer, Phyllocnistis citrella Stainton and mites. Sucrose octanoate rates tested ranged from 400 to 8000 ppm (0.1-2% formulated product). Our data suggest that both nymphal and adult D. citri as well as the mite complex tested would be equally controlled to levels of >90% at the higher concentrations of sucrose octanoate and that good coverage is key to efficacy.

  16. Induced resistance against the Asian citrus psyllid, Diaphorina citri, by β-aminobutyric acid in citrus.

    Science.gov (United States)

    Tiwari, Siddharth; Meyer, Wendy L; Stelinski, Lukasz L

    2013-10-01

    β-Aminobutyric acid (BABA) is known to induce resistance to microbial pathogens, nematodes and insects in several host plant/pest systems. The present study was undertaken to determine whether a similar effect of BABA occurred against the Asian citrus psyllid, Diaphorina citri Kuwayama, in citrus. A 25 mM drench application of BABA significantly reduced the number of eggs/plant as compared with a water control, whereas 200 and 100 mM applications of BABA reduced the numbers of nymphs/plant and adults/plants, respectively. A 5 mM foliar application of BABA significantly reduced the number of adults but not eggs or nymphs when compared with a water control treatment. In addition, leaf-dip bioassays using various concentrations (25–500 mM) of BABA indicated no direct toxic effect on 2nd and 5th instar nymphs or adult D. citri. BABA-treated plants were characterized by significantly lower levels of iron, magnesium, phosphorus, sodium, sulfur and zinc as compared with control plants. The expression level of the PR-2 gene (β-1,3-glucanase) in BABA-treated plants that were also damaged by D. citri adult feeding was significantly higher than in plants exposed to BABA, D. citri feeding alone or control plants. Our results indicate the potential for using BABA as a systemic acquired resistance management tool for D. citri.

  17. Dynamic insecticide susceptibility changes in Florida populations of Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Tiwari, Siddharth; Killiny, Nabil; Stelinski, Lukasz L

    2013-02-01

    Five field populations of Diaphorina citri Kuwayama from various regions of Florida were evaluated in 2011 for resistance to commonly used insecticides. Three diagnostic doses (LD50, LD75, and LD95), developed in 2009 using a laboratory susceptible population, were used to measure changes in susceptibility levels of field-collected populations as compared with a susceptible laboratory population. Further reductions in the susceptibility levels of D. citri to chlorpyriphos and fenpropathrin were determined, compared with results obtained in 2010. Mean percent mortality obtained from all five locations was significantly lower than observed with the laboratory susceptible population for all insecticides tested. Previously, expression of five CYP4 genes was implicated in contributing to insecticide metabolism in D. citri. In the current study, we compared the relative expression of these five CYP4 genes and their associated levels of protein expression among field-collected and laboratory susceptible populations. Expression of all CYP4 genes investigated was higher in field-collected populations when normalized against the laboratory susceptible population. There was an increased signal of a band corresponding to a 45 kDa protein in four of the five field populations as measured by the Western blot assay, which suggests increased production of cytochrome P450 enzymes. The current results indicate that insecticide resistance continues to increase in Florida populations ofD. citri, particularly to chlorpyriphos and fenpropathrin. However, there was no further decrease in susceptibility of Florida populations of D. citri to neonicotinoid insecticides in 2011 as compared with previous years.

  18. Chemical and behavioral analysis of the cuticular hydrocarbons from Asian citrus psyllid, Diaphorina citri.

    Science.gov (United States)

    Mann, Rajinder S; Rouseff, Russell L; Smoot, Jack; Rao, Nandikeswara; Meyer, Wendy L; Lapointe, Stephen L; Robbins, Paul S; Cha, Dong; Linn, Charles E; Webster, Francis X; Tiwari, Siddharth; Stelinski, Lukasz L

    2013-06-01

    Huanglongbing (HLB) is the most destructive disease of citrus worldwide. The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the vector of the phloem-inhabiting bacterium, Candidatus Liberibacter asiaticus, which is presumed to cause HLB in Florida citrus. Laboratory and field studies were conducted to examine the behavioral responses of male and female D. citri to their cuticular extracts. In olfactometer assays, more male D. citri were attracted to one, five, or 10 female cuticular extract equivalent units than blank controls. The results were confirmed in field studies in which clear or yellow traps baited with 10 female cuticular extract equivalent units attracted proportionately more males than clear traps baited with male cuticular extract or unbaited traps. Analyses of cuticular constituents of male and female D. citri revealed differences between the sexes in chemical composition of their cuticular extracts. Laboratory bioassays with synthetic chemicals identified from cuticular extracts indicated that dodecanoic acid attracted more males than clean air. Traps baited with dodecanoic acid did not increase total catch of D. citri as compared with blank traps at the dosages tested; however, the sex ratio of psyllid catch was male biased on traps baited with the highest lure loading dosage tested (10.0 mg).

  19. [Resistance realized heritability and risk assessment of Panonychus citri to avermectin and fenpropathrin].

    Science.gov (United States)

    He, Heng-guo; Zhao, Zhi-mo; Yan, Xiang-hui; Wang, Jin-jun

    2011-08-01

    On the basis of resistance breeding and selection in laboratory, and by using the threshold trait analysis in quantitative genetics, this paper studied the realized resistance heritability of Panonychus citri (McGregor) collected from Beibei of Chongqing to avermectin and fenpropathrin, and predicted the resistance risk of P. citri to these two acaricides. After 11- and 16-generations of selection with avermectin and fenpropathrin, the resistance of P. citri to the two acaricides increased by 3.8- and 29.9-fold, and the realized resistance heritability was 0.0475 and 0.1544, respectively. Under laboratory condition, to develop a 10-fold increase of resistance required 12-26 generations of selection for avermectin, and 7-16 generations of selection for fenpropathrin under the selection pressure of 50%-90% mortality for each generation. Under field condition, it would require more generations to develop the same resistance level. Comparing with bioacaricide avermectin, pyrethroid fenpropathrin had obviously higher resistance risk to P. citri. The results provided references for the resistance management of P. citri to acaricides. PMID:22097380

  20. Sulfur volatiles from Allium spp. affect Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), response to citrus volatiles.

    Science.gov (United States)

    Mann, R S; Rouseff, R L; Smoot, J M; Castle, W S; Stelinski, L L

    2011-02-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama, vectors Candidatus Liberibacter asiaticus (Las) and Candidatus Liberibacter americanus (Lam), the presumed causal agents of huanglongbing. D. citri generally rely on olfaction and vision for detection of host cues. Plant volatiles from Allium spp. (Alliaceae) are known to repel several arthropod species. We examined the effect of garlic chive (A. tuberosum Rottl.) and wild onion (A. canadense L.) volatiles on D. citri behaviour in a two-port divided T-olfactometer. Citrus leaf volatiles attracted significantly more D. citri adults than clean air. Volatiles from crushed garlic chive leaves, garlic chive essential oil, garlic chive plants, wild onion plants and crushed wild onion leaves all repelled D. citri adults when compared with clean air, with the first two being significantly more repellent than the others. However, when tested with citrus volatiles, only crushed garlic chive leaves and garlic chive essential oil were repellent, and crushed wild onions leaves were not. Analysis of the headspace components of crushed garlic chive leaves and garlic chive essential oil by gas chromatography-mass spectrometry revealed that monosulfides, disulfides and trisulfides were the primary sulfur volatiles present. In general, trisulfides (dimethyl trisulfide) inhibited the response of D. citri to citrus volatiles more than disulfides (dimethyl disulfide, allyl methyl disulfide, allyl disulfide). Monosulfides did not affect the behaviour of D. citri adults. A blend of dimethyl trisulfide and dimethyl disulfide in 1:1 ratio showed an additive effect on inhibition of D. citri response to citrus volatiles. The plant volatiles from Allium spp. did not affect the behaviour of the D. citri ecto-parasitoid Tamarixia radiata (Waterston). Thus, Allium spp. or the tri- and di-sulphides could be integrated into management programmes for D. citri without affecting natural enemies.

  1. Gross morphology and ultrastructure of the female reproductive system of Diaphorina citri (Hemiptera: Liviidae

    Directory of Open Access Journals (Sweden)

    Fabio Cleisto Alda Dossi

    2014-04-01

    Full Text Available The morphological traits of the female reproductive system of Diaphorina citri were examined in detail. Diaphorina citri has telotrophic ovaries with ovarioles organized as a "bouquet", displaying a rudimentary terminal filament and a syncytial tropharium. The vitellarium carries a single growing oocyte at each maturation cycle, which is connected with the tropharium by a nutritive cord. Morpho-functional changes occur during oocyte development, mainly during mid to late vitellogenesis. Morphological events such as the patency of the follicular cells and the intense traffic of vesicles through para- or intracellular processes, suggest a possible route for endosymbiont invasion of D. citri reproductive tissues. Similar events have been demonstrated to be involved in the process of ovariole invasion by endosymbionts in other sternorrhynchans that share reproductive traits with psyllids.

  2. Quantifying dispersal of Diaphorina citri (Hemiptera: Psyllidae) by immunomarking and potential impact of unmanaged groves on commercial citrus management.

    Science.gov (United States)

    Boina, Dhana Raj; Meyer, Wendy L; Onagbola, Ebenezer O; Stelinski, Lukasz L

    2009-08-01

    Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is an important pest of citrus. It is an efficient vector of three bacterial pathogens that are the presumptive causal agents of huanglongbing (HLB) or citrus greening disease. The movement patterns and dispersal capabilities of D. citri require study to better understand the spread of HLB and to improve management strategies for D. citri. A recently developed immunomarking technique that uses crude food proteins (chicken egg albumin, bovine casein, and soy protein) was evaluated for marking and tracking movement of D. citri in Florida citrus groves. In general, both egg and milk protein markers exhibited longer residual activity (35 d) than the soy protein marker (20 d) when applied to citrus leaves with a residual activity order of egg > milk > soy protein. However, residues of all three protein markers decreased with a simulated rain; this was more pronounced for soy protein than for egg and milk proteins. Temperature did not significantly affect acquisition of markers by adult D. citri. Egg, milk, and soy protein markers were detected on >90% of adult D. citri for up to 10, 10, and 5 d, respectively, after field application. Addition of tetrasodium ethylenediamine tetraacetic acid (water softener) and/or Silwet L-77 (wetting agent) to marker solutions did not affect longevity of detection. Each of the protein markers was detected on > or =80% of exposed D. citri for up to 30 d after direct application to adults. A field study was conducted to measure movement of D. citri between replicated pairs of 0.4 ha managed and unmanaged citrus plots separated by 60-100 m. Approximately 70% of captured D. citri were found marked 3 d after application of proteins in the field. Using two marker proteins, it was determined that D. citri moved bi-directionally between managed and unmanaged (abandoned) groves within 3 d with a greater number of D. citri adults moving from unmanaged into managed plots than from managed into

  3. First record of Diaphorina citri (Hemiptera: Psyllidae) in Ecuador infesting urban citrus and orange jasmine trees.

    Science.gov (United States)

    Cornejo, J F; Chica, E J

    2014-01-01

    Adults and nymphs of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), were collected in the Guayaquil, Samborondón, and Durán cantons in coastal Ecuador. Psyllids were found in high numbers in citrus (Citrus spp., Sapindales: Rutaceae) and orange jasmine (Murraya exotica [L.] Jack, Sapindales: Rutaceae) trees within the Guayaquil-Samborondon-Duran conurbation; however, none was found during scoutings in the main citrus producing areas in coastal Ecuador. To the best of our knowledge, this is the first report of D. citri in Ecuador and the Pacific coastal plain of South America. PMID:25527601

  4. First record of Diaphorina citri (Hemiptera: Psyllidae) in Ecuador infesting urban citrus and orange jasmine trees.

    Science.gov (United States)

    Cornejo, J F; Chica, E J

    2014-01-01

    Adults and nymphs of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), were collected in the Guayaquil, Samborondón, and Durán cantons in coastal Ecuador. Psyllids were found in high numbers in citrus (Citrus spp., Sapindales: Rutaceae) and orange jasmine (Murraya exotica [L.] Jack, Sapindales: Rutaceae) trees within the Guayaquil-Samborondon-Duran conurbation; however, none was found during scoutings in the main citrus producing areas in coastal Ecuador. To the best of our knowledge, this is the first report of D. citri in Ecuador and the Pacific coastal plain of South America.

  5. Dialeurodes citri (Ashmead, 1885 in the Adriatic Region of Croatia

    Directory of Open Access Journals (Sweden)

    Katja Žanić

    2001-09-01

    Full Text Available Dialeurodes citri (Hom. Aleyrodidae first invaded citrus orchards in the South Adriatic, near Dubrovnik, during 1977. Since the characteristics of the pest have not been studied in Croatia, this paper reviews its morphology, locations, host plant range and biology. Leaf samples, collected all over the Croatian coast and islands, were observed in the laboratory for purpose of creating a map with citrus whitefly locations, morphological description and a list of host plants. The pest biological cycle and population trend were investigated in the region of Split (May 1996-May 1998. The presence of citrus whitefly was confirmed in all citrus-growing areas of Croatia. The number of noted host plants was somewhat lower than in Mediterranean countries. Other than citrus, it also colonised and harmed laurustinus (Viburnum tinus Hemsl., persimmon (Diospyros kaki Thunb. and several plants of Oleaceae. The citrus whitefly had three generations on citrus per year. However, the part of larval population that belonged to second generation did not finish the post-embryonic development and it remained on the summer flush leaves and awaited the hibernation. The appearance of adults followed the appearance of young citrus growth. All development stages had three population peaks during vegetation period. The presence of young larval stages (L-1, L-2 was pronounced during the middle of June, August and October. The pest overwintered mainly as fourth instar larva. On deciduous persimmon trees it had two generations per year.

  6. Draft Genome Sequence of “Candidatus Liberibacter asiaticus” from Diaphorina citri in Guangdong, China

    OpenAIRE

    Wu, F.; Z. Zheng; Deng, X.; Cen, Y.; Liang, G; J. Chen

    2015-01-01

    The draft genome sequence of “Candidatus Liberibacter asiaticus” strain YCPsy from an Asian citrus psyllid (Diaphorina citri) in Guangdong, China, is reported here. The YCPsy strain has a genome size of 1,233,647 bp, 36.5% G+C content, 1,171 open reading frames (ORFs), and 53 RNAs.

  7. Chemical and behavioral analysis of the cuticular hydrocarbons from Asian citrus psyllid, Diaphorina citri

    Institute of Scientific and Technical Information of China (English)

    Raiinder S.Mann; Russell L.Rouseff; Jack Smoot; Nandikeswara Rao; Wendy L.Meyer; Stephen L.Lapointe; Paul S.Robbins

    2013-01-01

    Huanglongbing (HLB) is the most destructive disease of citrus worldwide.The Asian citrus psyllid,Diaphorina citri Kuwayama (Hemiptera:Psyllidae),is the vector of the phloem-inhabiting bacterium,Candidatus Liberibacter asiaticus,which is presumed to cause HLB in Florida citrus.Laboratory and field studies were conducted to examine the behavioral responses of male and female D.citri to their cuticular extracts.In olfactometer assays,more male D.citri were attracted to one,five,or 10 female cuticular extract equivalent units than blank controls.The results were confirmed in field studies in which clear or yellow traps baited with 10 female cuticular extract equivalent units attracted proportionately more males than clear traps baited with male cuticular extract or unbaited traps.Analyses of cuticular constituents of male and female D.citri revealed differences between the sexes in chemical composition of their cuticular extracts.Laboratory bioassays with synthetic chemicals identified from cuticular extracts indicated that dodecanoic acid attracted more males than clean air.Traps baited with dodecanoic acid did not increase total catch of D.cirri as compared with blank traps at the dosages tested; however,the sex ratio of psyllid catch was male biased on traps baited with the highest lure loading dosage tested (10.0 mg).

  8. Geïntegreerde bestrijding van citruswolluis Planococcus citri in roos

    NARCIS (Netherlands)

    Pijnakker, J.; Leman, A.; Staaij, van der M.

    2011-01-01

    Referaat Sinds begin 2000 is citruswolluis, Planococcus citri (Risso), een van de belangrijkste plagen geworden in de rozenteelt onder glas. Telers kiezen voor een meer geïntegreerde aanpak om andere plagen onder controle te houden en stoppen met het reguliere gebruik van breedwerkende middelen. Hie

  9. Geïntegreerde bestrijding van citruswolluis Planococcus citri in roos

    NARCIS (Netherlands)

    Pijnakker, J.; Leman, A.; Hennekam, M.

    2013-01-01

    Citruswolluis, Planococcus citri (Risso), is een van de belangrijkste plagen geworden in de rozenteelt onder glas. Er is inmiddels veel praktijkervaring met de toepassing van biologische bestrijders om haarden uit te roeien. Voor de professionele tuinbouw is de effectiviteit van deze aanpak doorgaan

  10. Reduced Susceptibility to Xanthomonas citri in Transgenic Citrus Expressing the FLS2 Receptor From Nicotiana benthamiana.

    Science.gov (United States)

    Hao, Guixia; Pitino, Marco; Duan, Yongping; Stover, Ed

    2016-02-01

    Overexpression of plant pattern-recognition receptors by genetic engineering provides a novel approach to enhance plant immunity and broad-spectrum disease resistance. Citrus canker disease associated with Xanthomonas citri is one of the most important diseases damaging citrus production worldwide. In this study, we cloned the FLS2 gene from Nicotiana benthamiana cDNA and inserted it into the binary vector pBinPlus/ARS to transform Hamlin sweet orange and Carrizo citrange. Transgene presence was confirmed by polymerase chain reaction (PCR) and gene expression of NbFLS2 was compared by reverse transcription quantitative PCR. Reactive oxygen species (ROS) production in response to flg22Xcc was detected in transgenic Hamlin but not in nontransformed controls. Low or no ROS production was detected from nontransformed Hamlin seedlings challenged with flg22Xcc. Transgenic plants highly expressing NbFLS2 were selected and were evaluated for resistance to canker incited by X. citri 3213. Our results showed that the integration and expression of the NbFLS2 gene in citrus can increase canker resistance and defense-associated gene expression when challenged with X. citri. These results suggest that canker-susceptible Citrus genotypes lack strong basal defense induced by X. citri flagellin and the resistance of these genotypes can be enhanced by transgenic expression of the flagellin receptor from a resistant species.

  11. Morphometric comparisons of Diaphorina citri (Hemiptera: Liviidae) populations from Iran, USA and Pakistan.

    Science.gov (United States)

    Lashkari, Mohammadreza; Hentz, Matthew G; Boykin, Laura M

    2015-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), vector of citrus greening disease pathogen, Huanglongbing (HLB), is considered the most serious pest of citrus in the world. Prior molecular based studies have hypothesized a link between the D. citri in Iran and the USA (Florida). The purpose of this study was to collect morphometric data from D. citri populations from Iran (mtCOI haplotype-1), Florida (mtCOI haplotype-1), and Pakistan (mtCOI haplotype-6), to determine whether different mtCOI haplotypes have a relationship to a specific morphometric variation. 240 samples from 6 ACP populations (Iran-Jiroft, Chabahar; Florida-Ft. Pierce, Palm Beach Gardens, Port St. Lucie; and Pakistan-Punjab) were collected for comparison. Measurements of 20 morphological characters were selected, measured and analysed using ANOVA and MANOVA. The results indicate differences among the 6 ACP populations (Wilks' lambda = 0.0376, F = 7.29, P citri species in this study, (1) Iran, (2) USA (Florida) and (3) Pakistan population. Morphometric comparisons provided further resolution to the mtCOI haplotypes and distinguished the Florida and Iranian populations. PMID:26038715

  12. The genetic structure of an invasive pest, the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Guidolin, Aline S; Fresia, Pablo; Cônsoli, Fernando L

    2014-01-01

    The Asian citrus psyllid Diaphorina citri is currently the major threat to the citrus industry as it is the vector of Candidatus Liberibacter, the causal agent of huanglongbing disease (HLB). D. citri is native to Asia and now colonizes the Americas. Although it has been known in some countries for a long time, invasion routes remain undetermined. There are no efficient control methods for the HLB despite the intensive management tools currently in use. We investigated the genetic variability and structure of populations of D. citri to aid in the decision making processes toward sustainable management of this species/disease. We employed different methods to quantify and compare the genetic diversity and structure of D. citri populations among 36 localities in Brazil, using an almost complete sequence of the cytochrome oxidase I (COI) gene. Our analyses led to the identification of two geographically and genetically structured groups. The indices of molecular diversity pointed to a recent population expansion, and we discuss the role of multiple invasion events in this scenario. We also argue that such genetic diversity and population structure may have implications for the best management strategies to be adopted for controlling this psyllid and/or the disease it vectors in Brazil. PMID:25545788

  13. Diaphorina citri (Hemiptera: Liviidae) Abundance in Puerto Rico Declines with Elevation.

    Science.gov (United States)

    Jenkins, David A; Hall, David G; Goenaga, Ricardo

    2015-02-01

    Diaphorina citri Kuwayama is the primary vector of Huanglongbing, the most devastating disease of citrus. D. citri populations in Puerto Rico were monitored with yellow sticky traps on citrus trees or other psyllid host plants at different elevations, ranging from 10 to 880 m above sea level. Trapping was conducted in March through May of 2013 and 2014 when psyllid populations usually are highest. Population levels of D. citri, based on the trapping data, varied among the sites, and there was a strong trend in both years for decreasing psyllid abundance with increased elevation based on the number of psyllids captured on traps and the proportion of trees shown to be infested. No psyllids were collected at an elevation of >600 m. Reduced populations at higher elevations could be a consequence of differences in temperature, air pressure, oxygen levels, ultraviolet light, or other factors alone or in combination. We discuss our results as they pertain to management of D. citri and Huanglongbing. PMID:26470127

  14. Draft Genome Sequence of "Candidatus Liberibacter asiaticus" from Diaphorina citri in Guangdong, China.

    Science.gov (United States)

    Wu, F; Zheng, Z; Deng, X; Cen, Y; Liang, G; Chen, J

    2015-01-01

    The draft genome sequence of "Candidatus Liberibacter asiaticus" strain YCPsy from an Asian citrus psyllid (Diaphorina citri) in Guangdong, China, is reported here. The YCPsy strain has a genome size of 1,233,647 bp, 36.5% G+C content, 1,171 open reading frames (ORFs), and 53 RNAs. PMID:26543132

  15. Molecular characterization of Wolbachia strains associated with the invasive Asian citrus psyllid Diaphorina citri in Brazil.

    Science.gov (United States)

    Guidolin, A S; Cônsoli, F L

    2013-02-01

    Wolbachia is a symbiont intensively studied due to its ability to interfere with their host's reproduction, and it has been recently proposed as an alternative tool to control insect pests or vectors of diseases. The Asian citrus psyllid Diaphorina citri is an important pest of citrus since it vectors the bacterium that causes the "Huanglongbing" disease in citrus. The frequency and diversity of Wolbachia associated with D. citri is unknown, limiting the utilization of Wolbachia as an alternative strategy for insect management. Thus, we aimed to determine the natural rate of infection, to characterize the Wolbachia strains associated with this psyllid by "multilocus sequencing typing" (MLST) and wsp analysis, and to verify the association of the symbiont to particular genotypes of the host. Analysis indicated Wolbachia infects 100 % of all specimens tested from all 15 sampled populations. MLST revealed the occurrence of five new sequence types (STs) of Wolbachia, while analysis based on the wsp sequences indicated only four different types of Wolbachia. ST-173 was predominant, while the remaining STs were population specific. Analysis of the host-symbiont relationship did not reveal any particular association of Wolbachia and haplotypes or a decrease in nucleotide diversity of D. citri in populations in which more than one ST was recorded. The consequences of the diversity of STs reported are still unknown, but the fact that Wolbachia infection is fixed and that there is one ST with a broad distribution highlights the use of this symbiont as an alternative strategy to control D. citri.

  16. Morphometric comparisons of Diaphorina citri (Hemiptera: Liviidae populations from Iran, USA and Pakistan

    Directory of Open Access Journals (Sweden)

    Mohammadreza Lashkari

    2015-05-01

    Full Text Available The Asian citrus psyllid (ACP, Diaphorina citri Kuwayama (Hemiptera: Liviidae, vector of citrus greening disease pathogen, Huanglongbing (HLB, is considered the most serious pest of citrus in the world. Prior molecular based studies have hypothesized a link between the D. citri in Iran and the USA (Florida. The purpose of this study was to collect morphometric data from D. citri populations from Iran (mtCOI haplotype-1, Florida (mtCOI haplotype-1, and Pakistan (mtCOI haplotype-6, to determine whether different mtCOI haplotypes have a relationship to a specific morphometric variation. 240 samples from 6 ACP populations (Iran—Jiroft, Chabahar; Florida—Ft. Pierce, Palm Beach Gardens, Port St. Lucie; and Pakistan—Punjab were collected for comparison. Measurements of 20 morphological characters were selected, measured and analysed using ANOVA and MANOVA. The results indicate differences among the 6 ACP populations (Wilks’ lambda = 0.0376, F = 7.29, P < 0.0001. The body length (BL, circumanal ring length (CL, antenna length (AL, forewing length (WL and Rs vein length of forewing (RL were the most important characters separating the populations. The cluster analysis showed that the Iran and Florida populations are distinct from each other but separate from the Pakistan population. Thus, three subgroups can be morphologically discriminated within D. citri species in this study, (1 Iran, (2 USA (Florida and (3 Pakistan population. Morphometric comparisons provided further resolution to the mtCOI haplotypes and distinguished the Florida and Iranian populations.

  17. The genetic structure of an invasive pest, the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Guidolin, Aline S; Fresia, Pablo; Cônsoli, Fernando L

    2014-01-01

    The Asian citrus psyllid Diaphorina citri is currently the major threat to the citrus industry as it is the vector of Candidatus Liberibacter, the causal agent of huanglongbing disease (HLB). D. citri is native to Asia and now colonizes the Americas. Although it has been known in some countries for a long time, invasion routes remain undetermined. There are no efficient control methods for the HLB despite the intensive management tools currently in use. We investigated the genetic variability and structure of populations of D. citri to aid in the decision making processes toward sustainable management of this species/disease. We employed different methods to quantify and compare the genetic diversity and structure of D. citri populations among 36 localities in Brazil, using an almost complete sequence of the cytochrome oxidase I (COI) gene. Our analyses led to the identification of two geographically and genetically structured groups. The indices of molecular diversity pointed to a recent population expansion, and we discuss the role of multiple invasion events in this scenario. We also argue that such genetic diversity and population structure may have implications for the best management strategies to be adopted for controlling this psyllid and/or the disease it vectors in Brazil.

  18. Draft genome sequence of “Candidatus Liberibacter asiaticus” from Diaphorina citri in Guangdong, China

    Science.gov (United States)

    The draft genome sequence of “Candidatus Liberibacter asiaticus” strain YCPsy from an Asian citrus psyllid (Diaphorina citri) in Guangdong of China is reported. The YCPsy strain has a genome size of 1,233,647 bp, 36.5% G+C content, 1,171 open reading frames (ORFs), and 53 RNAs....

  19. Repellency of Selected Psidium guajava cultivars to the Asian citrus psyllid, Diaphorina citri

    Science.gov (United States)

    Asiatic huanglongbing (HLB)(also known as citrus greening disease) is the most devastating disease of citrus worldwide. It is caused by a bacterium ‘Candidatus Liberibacter asiaticus’ and transmitted by the Asian citrus psyllid (ACP), Diaphorina citri. Considerable research has been conducted toward...

  20. Morphological description of the mouthparts of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae).

    Science.gov (United States)

    Garzo, E; Bonani, J P; Lopes, J R S; Fereres, A

    2012-01-01

    Scanning (SEM) and transmission (TEM) electron microscopy were used to elucidate the morphology of the rostrum, as well as the mandibular and maxillary stylets of the psyllid Diaphorina citri, vector of phloem-inhabiting bacteria associated with citrus huanglongbing (HLB) disease. D. citri has a cone-shaped rostrum that extends behind the pair of prothoracic coxae. The stylet bundle comprises a pair of mandibular (Md) and maxillary (Mx) stylets with a mean length of 513.3 μm; when retracted, their proximal portions form a loop and are stored in the crumena (Cr). Serial cross-sections of the rostrum revealed that the mandibles are always projected in front of the maxillary stylets. The two maxillary stylets form the food and salivary canals, with diameters of 0.9 μm and 0.4 μm respectively. These two canals merge at the end of the stylets forming a common duct with a length of 4.3 μm and a mean diameter of 0.9 μm. The acrostyle, a distinct anatomical structure present in the common duct of aphid maxillary stylets, was not observed by TEM in the ultrathin cross-sections of the common duct (CD) of D. citri. This study provides new information on D. citri mouthparts that may help to understand the feeding behaviour of this important vector of HLB-associated bacteria.

  1. The genetic structure of an invasive pest, the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae.

    Directory of Open Access Journals (Sweden)

    Aline S Guidolin

    Full Text Available The Asian citrus psyllid Diaphorina citri is currently the major threat to the citrus industry as it is the vector of Candidatus Liberibacter, the causal agent of huanglongbing disease (HLB. D. citri is native to Asia and now colonizes the Americas. Although it has been known in some countries for a long time, invasion routes remain undetermined. There are no efficient control methods for the HLB despite the intensive management tools currently in use. We investigated the genetic variability and structure of populations of D. citri to aid in the decision making processes toward sustainable management of this species/disease. We employed different methods to quantify and compare the genetic diversity and structure of D. citri populations among 36 localities in Brazil, using an almost complete sequence of the cytochrome oxidase I (COI gene. Our analyses led to the identification of two geographically and genetically structured groups. The indices of molecular diversity pointed to a recent population expansion, and we discuss the role of multiple invasion events in this scenario. We also argue that such genetic diversity and population structure may have implications for the best management strategies to be adopted for controlling this psyllid and/or the disease it vectors in Brazil.

  2. Internal extracellular bacteria of Diaphorina citri Kuwayama (Hemiptera: Psyllidae), the Asian citus psyllid

    Science.gov (United States)

    Internal bacteria were isolated and cultured from the Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), the insect which transmits the plant-infecting bacteria, Candidatus Liberibacter, known to infect and kill citrus trees, known as citrus greening disease. The bacteria from Di...

  3. Morphometric comparisons of Diaphorina citri (Hemiptera: Liviidae) populations from Iran, USA and Pakistan.

    Science.gov (United States)

    Lashkari, Mohammadreza; Hentz, Matthew G; Boykin, Laura M

    2015-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), vector of citrus greening disease pathogen, Huanglongbing (HLB), is considered the most serious pest of citrus in the world. Prior molecular based studies have hypothesized a link between the D. citri in Iran and the USA (Florida). The purpose of this study was to collect morphometric data from D. citri populations from Iran (mtCOI haplotype-1), Florida (mtCOI haplotype-1), and Pakistan (mtCOI haplotype-6), to determine whether different mtCOI haplotypes have a relationship to a specific morphometric variation. 240 samples from 6 ACP populations (Iran-Jiroft, Chabahar; Florida-Ft. Pierce, Palm Beach Gardens, Port St. Lucie; and Pakistan-Punjab) were collected for comparison. Measurements of 20 morphological characters were selected, measured and analysed using ANOVA and MANOVA. The results indicate differences among the 6 ACP populations (Wilks' lambda = 0.0376, F = 7.29, P citri species in this study, (1) Iran, (2) USA (Florida) and (3) Pakistan population. Morphometric comparisons provided further resolution to the mtCOI haplotypes and distinguished the Florida and Iranian populations.

  4. [Ovarian development and analysis of mating effects on ovary maturation of Diaphorina citri Kuwayama (Hemiptera: Psyllidae)].

    Science.gov (United States)

    Dossi, Fábio C A; Cônsoli, Fernando L

    2010-01-01

    As many other insects with a restricted diet, the citrus psyllid Diaphorina citri Kuwayama, which vector the causing agent of the Huanglongbing, the bacteria Candidatus Liberibacter spp., is intimately associated with symbiotic microorganisms. These mutualist symbionts play a key role on their host nutritional ecology, and are vertically transmitted to the progeny. However, despite the role symbionts play on host development and reproduction, and the growing opportunities of exploitation of the association insect-symbiont to control insect vectored-pathogens, there are very few studies on the host reproductive biology and on the symbiont transovarial transmission. Therefore, we aimed at analyzing the ovary development during D. citri adulthood, and at verifying for the mating requirement as a trigger to initiate ovary development. Newly-emerged D. citri females were grouped as virgin or mated and ovary development was observed during adulthood. Newly-emerged females have immature ovaries, and ovaries remain without any mature eggs until females mate. Once female mates, the vitellogenesis synthesis and uptake are estimulated, and oocytes are quickly developed. Oocytes maturation in ovarioles is metachronic, with only one oocyte developing at a time in each oogenic cycle. Morphological observations of the reproductive system including the ovaries and spermatheca, after the first cluster of eggs is laid, indicated D. citri is polyandrous, and may require multiple mating to develop additional oogenic maturation cycles.

  5. Draft Genome Sequence of "Candidatus Liberibacter asiaticus" from Diaphorina citri in Guangdong, China.

    Science.gov (United States)

    Wu, F; Zheng, Z; Deng, X; Cen, Y; Liang, G; Chen, J

    2015-01-01

    The draft genome sequence of "Candidatus Liberibacter asiaticus" strain YCPsy from an Asian citrus psyllid (Diaphorina citri) in Guangdong, China, is reported here. The YCPsy strain has a genome size of 1,233,647 bp, 36.5% G+C content, 1,171 open reading frames (ORFs), and 53 RNAs.

  6. Diaphorina citri (Hemiptera: Liviidae) Abundance in Puerto Rico Declines with Elevation.

    Science.gov (United States)

    Jenkins, David A; Hall, David G; Goenaga, Ricardo

    2015-02-01

    Diaphorina citri Kuwayama is the primary vector of Huanglongbing, the most devastating disease of citrus. D. citri populations in Puerto Rico were monitored with yellow sticky traps on citrus trees or other psyllid host plants at different elevations, ranging from 10 to 880 m above sea level. Trapping was conducted in March through May of 2013 and 2014 when psyllid populations usually are highest. Population levels of D. citri, based on the trapping data, varied among the sites, and there was a strong trend in both years for decreasing psyllid abundance with increased elevation based on the number of psyllids captured on traps and the proportion of trees shown to be infested. No psyllids were collected at an elevation of >600 m. Reduced populations at higher elevations could be a consequence of differences in temperature, air pressure, oxygen levels, ultraviolet light, or other factors alone or in combination. We discuss our results as they pertain to management of D. citri and Huanglongbing.

  7. Influence of temperature and humidity on survival of Penicillium digitatum and Geotrichum citri-aurantii

    Science.gov (United States)

    Longevity of conidia of Penicillium digitatum and arthrospores of Geotrichum citri-aurantii, cause of green mold and sour rot of citrus, respectively, was determined. Conidia of P. digitatum were exposed to ambient summer conditions in central California or to conditions of controlled temperature an...

  8. Regulation of three isoforms of SOD gene by environmental stresses in citrus red mite, Panonychus citri.

    Science.gov (United States)

    Feng, Ying-Cai; Liao, Chong-Yu; Xia, Wen-Kai; Jiang, Xuan-Zhao; Shang, Feng; Yuan, Guo-Rui; Wang, Jin-Jun

    2015-09-01

    Superoxide dismutase (SOD) is a family of enzymes with multiple isoforms that possess antioxidative abilities in response to environmental stresses. Panonychus citri is one of the most important pest mites and has a global distribution. In this study, three distinct isoforms of SOD were cloned from P. citri and identified as cytoplasmic Cu-ZnSOD (PcSOD1), extracellular Cu-ZnSOD (PcSOD2), and mitochondrial MnSOD (PcSOD3). mRNA expression level analysis showed that all three isoforms were up-regulated significantly after exposure to the acaricide abamectin and to UV-B ultraviolet irradiation. In particular, PcSOD3 was up-regulated under almost all environmental stresses tested. The fold change of PcSOD3 expression was significantly higher than those of the two Cu-ZnSOD isoforms. Taken together, the results indicate that abamectin and UV-B can induce transcripts of all three SOD isoforms in P. citri. Furthermore, PcSOD3 seems to play a more important role in P. citri tolerance to oxidative stress. PMID:26063404

  9. Gender differences and effect of photophase on Asian citrus psyllid (Diaphorina citri Kuwayama) feeding behavior

    Science.gov (United States)

    Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), thought to be primarily a phloem-feeding insect, transmits the presumptive pathogen for Huanglongbing, ‘Candidatus Liberibacter asiaticus’. Because this bacterium is restricted to the phloem and bacterial transmission is the res...

  10. Insecticidal suppression of Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae) vector of huanglongbing pathogens.

    Science.gov (United States)

    Qureshi, Jawwad A; Kostyk, Barry C; Stansly, Philip A

    2014-01-01

    Diaphorina citri vectors pathogens that cause 'huanglongbing' or citrus greening disease which poses a serious threat to citrus production worldwide. Vector suppression is critical to reduce disease spread. Efficacy is a main concern when choosing an insecticide. Insecticidal treatments of 49 products or 44 active ingredients (a.i) labeled or experimental were field tested between 2005-2013 as foliar sprays (250 treatments, 39 a.i) or soil applications (47 treatments, 9 a.i) to control D. citri in citrus. A combined effect of nymphal and adult suppression in response to sprays of 23 insecticides representing 9 modes of action (MoA) groups and 3 unknown MoA provided more than 90% reduction of adult D. citri over 24-68 days. Observable effects on nymphs were generally of shorter duration due to rapid maturation of flush. However, reduction of 76-100% nymphs or adults over 99-296 days was seen on young trees receiving drenches of the neonicotinoids imidacloprid, thiamethoxam or clothianidin (MoA 4A) and a novel anthranilic diamide, cyantraniliprole (MoA 28). Effective products identified for foliar sprays to control D. citri provide sufficient MoA groups for rotation to delay evolution of insecticide resistance by D. citri and other pests. However, cyantraniliprole is now the only available alternative for rotation with neonicotinoids in soil application to young trees. Sprays of up to eight of the most effective insecticides could be rotated over a year without repetition of any MoA and little or no recourse to neonicotinoids or cyantraniliprole, so important for protection of young trees. Other considerations effecting decisions of what and when to spray include prevalence of huanglongbing, pest pressure, pre-harvest intervals, overall budget, equipment availability, and conservation of beneficial arthropods. Examples of spray programs utilizing broad-spectrum and relatively selective insecticides are provided to improve vector management and may vary depending on

  11. The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri.

    Science.gov (United States)

    Stockton, Dara G; Martini, Xavier; Patt, Joseph M; Stelinski, Lukasz L

    2016-01-01

    Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri; vector of the causal agent of citrus greening disease or huanglongbing. We investigated: a) whether development on specific host plant species influenced host plant preference in mature D. citri; and b) the extent of associative learning in D. citri in the form of simple and compound conditioning. Learning was measured by cue selection in a 2-choice behavioral assay and compared to naïve controls. Our results showed that learned responses in D. citri are complex and diverse. The developmental host plant species influenced adult host plant preference, with female psyllids preferring the species on which they were reared. However, such preferences were subject to change with the introduction of an alternative host plant within 24-48 hrs, indicating a large degree of experience-dependent response plasticity. Additionally, learning occurred for multiple sensory modalities where novel olfactory and visual environmental cues were associated with the host plant. However, males and females displayed differing discriminatory abilities. In compound conditioning tasks, males exhibited recognition of a compound stimulus alone while females were capable of learning the individual components. These findings suggest D. citri are dynamic animals that demonstrate host plant preference based on developmental and adult experience and can learn to recognize olfactory and visual host plant stimuli in ways that may be sex specific. These experience-based associations are likely used by adults to locate and select suitable host plants for feeding and reproduction and may suggest the need for more tailored lures and traps, which reflect region-specific cultivars or predominate Rutaceae in the area

  12. The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri.

    Directory of Open Access Journals (Sweden)

    Dara G Stockton

    Full Text Available Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri; vector of the causal agent of citrus greening disease or huanglongbing. We investigated: a whether development on specific host plant species influenced host plant preference in mature D. citri; and b the extent of associative learning in D. citri in the form of simple and compound conditioning. Learning was measured by cue selection in a 2-choice behavioral assay and compared to naïve controls. Our results showed that learned responses in D. citri are complex and diverse. The developmental host plant species influenced adult host plant preference, with female psyllids preferring the species on which they were reared. However, such preferences were subject to change with the introduction of an alternative host plant within 24-48 hrs, indicating a large degree of experience-dependent response plasticity. Additionally, learning occurred for multiple sensory modalities where novel olfactory and visual environmental cues were associated with the host plant. However, males and females displayed differing discriminatory abilities. In compound conditioning tasks, males exhibited recognition of a compound stimulus alone while females were capable of learning the individual components. These findings suggest D. citri are dynamic animals that demonstrate host plant preference based on developmental and adult experience and can learn to recognize olfactory and visual host plant stimuli in ways that may be sex specific. These experience-based associations are likely used by adults to locate and select suitable host plants for feeding and reproduction and may suggest the need for more tailored lures and traps, which reflect region-specific cultivars or predominate

  13. Multimodal cues drive host-plant assessment in Asian citrus psyllid (Diaphorina citri).

    Science.gov (United States)

    Patt, Joseph M; Meikle, William G; Mafra-Neto, Agenor; Sétamou, Mamoudou; Mangan, Robert; Yang, Chenghai; Malik, Nasir; Adamczyk, John J

    2011-12-01

    Asian citrus psyllid (Diaphorina citri) transmits the causal agent of Huanglongbing, a devastating disease of citrus trees. In this study we measured behavioral responses of D. citri to combinations of visual, olfactory, and gustatory stimuli in test arenas. Stimuli were presented to the psyllids in droplets or lines of an emulsified wax formulation in two different arena types in no-choice tests. First, when placed on a colored ring situated halfway between the center and perimeter of a petri dish, D. citri spent more time on yellow versus gray rings; however, this response disappeared when either gray or yellow wax droplets were applied. When the psyllids were presented with droplets scented with terpenes, the response to both scent and color was increased. The addition of a dilute (≍0.1 M) sucrose solution to the wax droplets increased the magnitude of D. citri responses. Next, groups of D. citri were placed on plastic laboratory film covering a sucrose solution, to mimic a leaf surface. Test stimuli were presented via two 'midribs' made from lines of emulsified wax formulation. Probing levels were measured as a function of color saturation and scent composition, and concentration. The test scents were based on qualitatively major volatiles emitted by Murraya paniculata (L.) Jack, Citrus aurantifolia (Christm.) Swingle, and C. sinensis (L.) Osbeck. The highest probing response was observed on the middle concentration (20-μl scent/10 ml wax formulation) of the C. aurantifolia-scented wax lines. Results indicate that there are interactive effects between the different sensory modalities in directing host-plant assessment behavior.

  14. Insecticidal suppression of Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae vector of huanglongbing pathogens.

    Directory of Open Access Journals (Sweden)

    Jawwad A Qureshi

    Full Text Available Diaphorina citri vectors pathogens that cause 'huanglongbing' or citrus greening disease which poses a serious threat to citrus production worldwide. Vector suppression is critical to reduce disease spread. Efficacy is a main concern when choosing an insecticide. Insecticidal treatments of 49 products or 44 active ingredients (a.i labeled or experimental were field tested between 2005-2013 as foliar sprays (250 treatments, 39 a.i or soil applications (47 treatments, 9 a.i to control D. citri in citrus. A combined effect of nymphal and adult suppression in response to sprays of 23 insecticides representing 9 modes of action (MoA groups and 3 unknown MoA provided more than 90% reduction of adult D. citri over 24-68 days. Observable effects on nymphs were generally of shorter duration due to rapid maturation of flush. However, reduction of 76-100% nymphs or adults over 99-296 days was seen on young trees receiving drenches of the neonicotinoids imidacloprid, thiamethoxam or clothianidin (MoA 4A and a novel anthranilic diamide, cyantraniliprole (MoA 28. Effective products identified for foliar sprays to control D. citri provide sufficient MoA groups for rotation to delay evolution of insecticide resistance by D. citri and other pests. However, cyantraniliprole is now the only available alternative for rotation with neonicotinoids in soil application to young trees. Sprays of up to eight of the most effective insecticides could be rotated over a year without repetition of any MoA and little or no recourse to neonicotinoids or cyantraniliprole, so important for protection of young trees. Other considerations effecting decisions of what and when to spray include prevalence of huanglongbing, pest pressure, pre-harvest intervals, overall budget, equipment availability, and conservation of beneficial arthropods. Examples of spray programs utilizing broad-spectrum and relatively selective insecticides are provided to improve vector management and may vary

  15. Influence of posttreatment temperature on the toxicity of insecticides against Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Boina, Dhana Raj; Onagbola, Ebenezer O; Salyani, Masoud; Stelinski, Lukasz L

    2009-04-01

    The psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is one of the most important pests of citrus worldwide because it efficiently vectors three bacteria in the genus Candidatus Liberibacter that cause the devastating citrus greening disease (huanglongbing). Current management practices for this insect pest rely on multiple sprays of foliar insecticides and one or two applications of soil systemic insecticides per season. Effective psyllid and disease management in Florida requires insecticide applications throughout the entire season over wide ranging temperature and environmental conditions. Using a petri dish bioassay technique, the effect of posttreatment temperature (range, 17-37 degrees C) on the toxicity of selected organophosphate (chlorpyrifos and dimethoate), carbamate (carbaryl), avermectin (abamectin), pyrethroid (bifenthrin, zeta-cypermethrin, fenpropathrin, and lambda-cyhalothrin), and neonicotinoid (acetamiprid, imidacloprid, and thiamethoxam) insecticides was evaluated against adult D. citri. The toxicity of both organophosphates showed a positive temperature correlation within the 17-37 degrees C range. Similarly, carbaryl (carbamate) and abamectin (avermectin) exhibited increased toxicity with increasing temperature from 17 to 37 degrees C, with abamectin showing higher overall temperature-dependent toxicity against D. citri adults than carbaryl. With the exception of bifenthrin, which showed a positive temperature-dependent toxicity correlation between 27 and 37 degrees C, all other pyrethroids tested exhibited a negative correlation over the temperature range examined. The toxicity of fenpropathrin and lambda-cyhalothrin dramatically decreased with increasing temperature from 17 to 37 degrees C. The neonicotinoids imidacloprid and thiamethoxam exhibited a mixed response to increasing temperature, whereas acetamiprid showed a positive temperature correlation. However, all three neonicotinoids showed positive temperature-dependent toxicity

  16. Insecticidal suppression of Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae) vector of huanglongbing pathogens.

    Science.gov (United States)

    Qureshi, Jawwad A; Kostyk, Barry C; Stansly, Philip A

    2014-01-01

    Diaphorina citri vectors pathogens that cause 'huanglongbing' or citrus greening disease which poses a serious threat to citrus production worldwide. Vector suppression is critical to reduce disease spread. Efficacy is a main concern when choosing an insecticide. Insecticidal treatments of 49 products or 44 active ingredients (a.i) labeled or experimental were field tested between 2005-2013 as foliar sprays (250 treatments, 39 a.i) or soil applications (47 treatments, 9 a.i) to control D. citri in citrus. A combined effect of nymphal and adult suppression in response to sprays of 23 insecticides representing 9 modes of action (MoA) groups and 3 unknown MoA provided more than 90% reduction of adult D. citri over 24-68 days. Observable effects on nymphs were generally of shorter duration due to rapid maturation of flush. However, reduction of 76-100% nymphs or adults over 99-296 days was seen on young trees receiving drenches of the neonicotinoids imidacloprid, thiamethoxam or clothianidin (MoA 4A) and a novel anthranilic diamide, cyantraniliprole (MoA 28). Effective products identified for foliar sprays to control D. citri provide sufficient MoA groups for rotation to delay evolution of insecticide resistance by D. citri and other pests. However, cyantraniliprole is now the only available alternative for rotation with neonicotinoids in soil application to young trees. Sprays of up to eight of the most effective insecticides could be rotated over a year without repetition of any MoA and little or no recourse to neonicotinoids or cyantraniliprole, so important for protection of young trees. Other considerations effecting decisions of what and when to spray include prevalence of huanglongbing, pest pressure, pre-harvest intervals, overall budget, equipment availability, and conservation of beneficial arthropods. Examples of spray programs utilizing broad-spectrum and relatively selective insecticides are provided to improve vector management and may vary depending on

  17. The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri.

    Science.gov (United States)

    Stockton, Dara G; Martini, Xavier; Patt, Joseph M; Stelinski, Lukasz L

    2016-01-01

    Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri; vector of the causal agent of citrus greening disease or huanglongbing. We investigated: a) whether development on specific host plant species influenced host plant preference in mature D. citri; and b) the extent of associative learning in D. citri in the form of simple and compound conditioning. Learning was measured by cue selection in a 2-choice behavioral assay and compared to naïve controls. Our results showed that learned responses in D. citri are complex and diverse. The developmental host plant species influenced adult host plant preference, with female psyllids preferring the species on which they were reared. However, such preferences were subject to change with the introduction of an alternative host plant within 24-48 hrs, indicating a large degree of experience-dependent response plasticity. Additionally, learning occurred for multiple sensory modalities where novel olfactory and visual environmental cues were associated with the host plant. However, males and females displayed differing discriminatory abilities. In compound conditioning tasks, males exhibited recognition of a compound stimulus alone while females were capable of learning the individual components. These findings suggest D. citri are dynamic animals that demonstrate host plant preference based on developmental and adult experience and can learn to recognize olfactory and visual host plant stimuli in ways that may be sex specific. These experience-based associations are likely used by adults to locate and select suitable host plants for feeding and reproduction and may suggest the need for more tailored lures and traps, which reflect region-specific cultivars or predominate Rutaceae in the area

  18. Endosymbiont hunting in the metagenome of Asian citrus psyllid (Diaphorina citri) (7th Annual SFAF Meeting, 2012)

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Surya [Cornell University

    2012-06-01

    Surya Saha on "Endosymbiont hunting in the metagenome of Asian citrus psyllid (Diaphorina citri)" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  19. Living on the Edges: Spatial Niche Occupation of Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), in Citrus Groves

    OpenAIRE

    Mamoudou Sétamou; David W Bartels

    2015-01-01

    The spatial niche occupation of the Asian citrus psyllid, Diaphorina citri Kuwayama, 1908, was evaluated to determine its field colonization and food resource exploitation strategies in citrus groves. Mature grapefruit and sweet orange groves were surveyed as part of an area-wide program in 2009-2010 to determine D. citri population densities and between-tree distribution. In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a str...

  20. Identification and Characterization of Seven Glutathione S-Transferase Genes from Citrus Red Mite, Panonychus citri (McGregor)

    OpenAIRE

    Liao, Chong-Yu; Zhang, Kun; Niu, Jin-Zhi; Ding, Tian-Bo; Zhong, Rui; Xia, Wen-Kai; Dou, Wei; Wang, Jin-Jun

    2013-01-01

    The citrus red mite, Panonychus citri (McGregor), is a global citrus pest, and has developed severe resistance to several types of acaricides. However, the molecular mechanisms of resistance in this mite remain unknown. In this study, seven full-length cDNAs encoding glutathione S-transferases (GSTs) genes were identified and characterized in P. citri. The effects of pyridaben and fenpropathrin exposure on the expression of these genes were also investigated. Phylogenetic analysis revealed th...

  1. Survey of endosymbionts in the Diaphorina citri metagenome and assembly of a Wolbachia wDi draft genome.

    Science.gov (United States)

    Saha, Surya; Hunter, Wayne B; Reese, Justin; Morgan, J Kent; Marutani-Hert, Mizuri; Huang, Hong; Lindeberg, Magdalen

    2012-01-01

    Diaphorina citri (Hemiptera: Psyllidae), the Asian citrus psyllid, is the insect vector of Ca. Liberibacter asiaticus, the causal agent of citrus greening disease. Sequencing of the D. citri metagenome has been initiated to gain better understanding of the biology of this organism and the potential roles of its bacterial endosymbionts. To corroborate candidate endosymbionts previously identified by rDNA amplification, raw reads from the D. citri metagenome sequence were mapped to reference genome sequences. Results of the read mapping provided the most support for Wolbachia and an enteric bacterium most similar to Salmonella. Wolbachia-derived reads were extracted using the complete genome sequences for four Wolbachia strains. Reads were assembled into a draft genome sequence, and the annotation assessed for the presence of features potentially involved in host interaction. Genome alignment with the complete sequences reveals membership of Wolbachia wDi in supergroup B, further supported by phylogenetic analysis of FtsZ. FtsZ and Wsp phylogenies additionally indicate that the Wolbachia strain in the Florida D. citri isolate falls into a sub-clade of supergroup B, distinct from Wolbachia present in Chinese D. citri isolates, supporting the hypothesis that the D. citri introduced into Florida did not originate from China.

  2. Incidence of invasive Diaphorina citri (Hemiptera: Psyllidae) and its introduced parasitoid Tamarixia radiata (Hymenoptera: Eulophidae) in Florida citrus.

    Science.gov (United States)

    Qureshi, Jawwad A; Rogers, Michael E; Hall, David G; Stansly, Philip A

    2009-02-01

    Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vectors the bacterium Candidatus Liberibacter asiaticus, one of the causal organisms of the devastating citrus disease "huanglongbing" or citrus greening. In the United States, D. citri was first discovered in Florida, in 1998. Tamarixia radiata Waterston (Hymenoptera: Eulophidae) was imported from Asia and released in Florida in 1999-2001 to improve biological control of D. citri before citrus greening was detected in Florida in 2005. Florida citrus groves were surveyed during 2006-2007 for D. citri and T. radiata. Results showed that D. citri was established in all 28 citrus groves surveyed across 16 counties. Adult populations averaged 3.52, 1.27, and 1.66 individuals per "tap" sample at locations in the central, southwest, and eastern coastal regions, respectively. A tap sample consisted of 22- by 28-cm white paper sheet (on a clipboard) held under branches selected at random that were tapped three times. Averages of 67, 44, and 45% citrus shoots infested with psyllid eggs or nymphs were obtained in the central, southwest, and eastern coastal regions, respectively. T. radiata was recovered from fourth- and fifth-instar psyllid nymphs at 26 of the 28 locations. However, apparent parasitism rates were variable and averaged citri and thereby reduce psyllid populations and spread of citrus greening disease.

  3. Survey of endosymbionts in the Diaphorina citri metagenome and assembly of a Wolbachia wDi draft genome.

    Directory of Open Access Journals (Sweden)

    Surya Saha

    Full Text Available Diaphorina citri (Hemiptera: Psyllidae, the Asian citrus psyllid, is the insect vector of Ca. Liberibacter asiaticus, the causal agent of citrus greening disease. Sequencing of the D. citri metagenome has been initiated to gain better understanding of the biology of this organism and the potential roles of its bacterial endosymbionts. To corroborate candidate endosymbionts previously identified by rDNA amplification, raw reads from the D. citri metagenome sequence were mapped to reference genome sequences. Results of the read mapping provided the most support for Wolbachia and an enteric bacterium most similar to Salmonella. Wolbachia-derived reads were extracted using the complete genome sequences for four Wolbachia strains. Reads were assembled into a draft genome sequence, and the annotation assessed for the presence of features potentially involved in host interaction. Genome alignment with the complete sequences reveals membership of Wolbachia wDi in supergroup B, further supported by phylogenetic analysis of FtsZ. FtsZ and Wsp phylogenies additionally indicate that the Wolbachia strain in the Florida D. citri isolate falls into a sub-clade of supergroup B, distinct from Wolbachia present in Chinese D. citri isolates, supporting the hypothesis that the D. citri introduced into Florida did not originate from China.

  4. Deinococcus citri sp. nov., isolated from citrus leaf canker lesions.

    Science.gov (United States)

    Ahmed, Iftikhar; Abbas, Saira; Kudo, Takuji; Iqbal, Muhammad; Fujiwara, Toru; Ohkuma, Moriya

    2014-12-01

    A Gram-stain-positive, strictly aerobic, non-motile, coccoid bacterium, designated NCCP-154(T), was isolated from citrus leaf canker lesions and was subjected to a polyphasic taxonomic study. Strain NCCP-154(T) grew at 10-37 °C (optimum 30 °C) and at pH 7.0-8.0 (optimum pH 7.0). The novel strain exhibited tolerance of UV irradiation (>1000 J m(-2)). Based on 16S rRNA gene sequence analysis, strain NCCP-154(T) showed the highest similarity to Deinococcus gobiensis CGMCC 1.7299(T) (98.8 %), and less than 94 % similarity to other closely related taxa. The chemotaxonomic data [major menaquinone, MK-8; cell-wall peptidoglycan type, A3β (Orn-Gly2); major fatty acids, summed feature 3 (C16 : 1ω7c/iso-C15 : 0 2-OH; 35.3 %) followed by C16 : 0 (12.7 %), iso-C17 : 1ω9c (9.2 %), C17 : 1ω8c (7.4 %) and iso-C17 : 0 (6.9 %); major polar lipids made up of several unidentified phosphoglycolipids and glycolipids and an aminophospholipid, and mannose as the predominant whole-cell sugar] also supported the affiliation of strain NCCP-154(T) to the genus Deinococcus. The level of DNA-DNA relatedness between strain NCCP-154(T) and D. gobiensis JCM 16679(T) was 63.3±3.7 %. The DNA G+C content of strain NCCP-154(T) was 70.0 mol%. Based on the phylogenetic analyses, DNA-DNA hybridization and physiological and biochemical characteristics, strain NCCP-154(T) can be differentiated from species with validly published names. Therefore, it represents a novel species of the genus Deinococcus. The name Deinococcus citri sp. nov. is proposed, with the type strain NCCP-154(T) ( = JCM 19024(T) = DSM 24791(T) = KCTC 13793(T)).

  5. Parallel evolution of cytochrome b mediated bifenazate resistance in the citrus red mite Panonychus citri.

    Science.gov (United States)

    Van Leeuwen, T; Van Nieuwenhuyse, P; Vanholme, B; Dermauw, W; Nauen, R; Tirry, L

    2011-02-01

    Bifenazate is a recently developed acaricide that is mainly used to control spider mites on a variety of crops. Although first thought to be a neurotoxin, genetic evidence obtained from bifenazate resistant Tetranychus urticae strains suggested an alternative mode of action as a Qo pocket inhibitor of the mitochondrial complex III. In this study, we reveal how bifenazate resistance in strains of Panonychus citri is maternally inherited and can confer cross-resistance to the known Qo inhibitor acequinocyl. The mitochondrial genome of P. citri was sequenced and Qo pocket mutations were shown to be linked with the resistant trait. Parallel evolution of cytochrome b mediated bifenazate resistance corroborates the alternative mode of action and yet again illustrates that care should be taken when employing Qo inhibitors as crop protection compounds. PMID:20735493

  6. Structural and functional analyses of the putrescine binding protein PotF from Xanthomonas citri

    International Nuclear Information System (INIS)

    Full text: The focus of our group is to determinate the role of ABC transporters in the physiology and growth of Xanthomonas citri, a phytopathogenic bacteria that infects citrus plants causing significant losses for the economy. One of the ABC transporters identified in the X. citri genome and that was showed to be active during the infection in Citrus sinensis plants was the putrescine transporter. This transporter consists of two internal membrane proteins PotG and PotH that form a pore, a cytoplasmic protein that gives energy for the transport and the periplasmic-binding protein PotF, which is responsible for the affinity and specificity of the system. Its function is associated to the microbial carcinogenesis, biofilm formation, escape from phagolysosomes, bacteriocin production, toxin activity and protection from oxidative and acid stress. In this work, we show for the first time, the expression, purification, functional and structural analyses of the X. citri PotF protein. The PotF was expressed from Escherichia coli cells strain Arctic, as a 40 kDa soluble protein, after induction of IPTG for twenty four hours at thirteen deg C. Using immobilized metal affinity chromatography for purification, the protein was eluted in the fractions with 10-500 mM of imidazole. To test the folding and cability to bind putrescine, spectroscopic analyses were performed using circular dichroism and intrinsic fluorescence. The data showed that PotF suffers conformational changes in presence of ligands and in different pH, suggesting a possible interaction with the tested ligand. Moreover, based on bioinformatics studies and molecular modeling analyses, we showed that X. citri PotF is highly conserved when compared to orthologs present in other bacteria, including the residues that form the ligand-binding site. The production of PotF in a soluble and stable form will allow us to start the crystallization trials in attempt to solve its structure. (author)

  7. Genomic Insights into the Evolutionary Origin of Xanthomonas axonopodis pv. citri and Its Ecological Relatives

    OpenAIRE

    Midha, Samriti; Patil, Prabhu B.

    2014-01-01

    Xanthomonas axonopodis pv. citri (Xac) is the causal agent of citrus bacterial canker (CBC) and is a serious problem worldwide. Like CBC, several important diseases in other fruits, such as mango, pomegranate, and grape, are also caused by Xanthomonas pathovars that display remarkable specificity toward their hosts. While citrus and mango diseases were documented more than 100 years ago, the pomegranate and grape diseases have been known only since the 1950s and 1970s, respectively. Interesti...

  8. Molecular Evidence of Polyandry in the Citrus Mealybug, Planococcus citri (Hemiptera: Pseudococcidae)

    OpenAIRE

    Seabra, Sofia G.; Brás, Patricia G.; Vera Zina; Elsa Borges da Silva; Maria Teresa Rebelo; Elisabete Figueiredo; Zvi Mendel; Paulo, Octávio S.; José Carlos Franco

    2013-01-01

    The occurrence of polyandry in Planococcus citri , presumed by earlier observations of mating behavior, was confirmed using microsatellite genotyping of pools of over 400 eggs resulting from controlled crosses of one female with two males. The genetic contribution of both mated males was confirmed in 13 out of 43 crosses. In three crosses it was possible to determine that only the first male fertilized the eggs, which may be due to sperm competition or unviable sperm supply. The microsatellit...

  9. Characterization and molecular cloning in Escherichia coli of a plasmid from the mollicute Spiroplasma citri.

    OpenAIRE

    Mouches, C; Barroso, G.; Bové, J M

    1983-01-01

    Two plasmids, pMH1 with 7 kilobase pairs and pM41 with 8 kilobase pairs, were purified from the plant pathogen Spiroplasma citri and characterized by restriction mapping. Upon in vitro DNA recombination with plasmid pBR328 as a vector, we have cloned pMH1 in Escherichia coli. A radioactive probe obtained upon nick translation of the recombinant plasmid was used to further characterize and compare pMH1 and pM41.

  10. Novel diagnosis for citrus stubborn disease by detection of a spiroplasma citri-secreted protein.

    Science.gov (United States)

    Shi, Jinxia; Pagliaccia, Deborah; Morgan, Robyn; Qiao, Yongli; Pan, Songqin; Vidalakis, Georgios; Ma, Wenbo

    2014-02-01

    Citrus stubborn disease (CSD), first identified in California, is a widespread bacterial disease found in most arid citrus-producing regions in the United States and the Mediterranean Region. The disease is caused by Spiroplasma citri, an insect-transmitted and phloem-colonizing bacterium. CSD causes significant tree damage resulting in loss of fruit production and quality. Detection of CSD is challenging due to low and fluctuating titer and sporadic distribution of the pathogen in infected trees. In this study, we report the development of a novel diagnostic method for CSD using an S. citri-secreted protein as the detection marker. Microbial pathogens secrete a variety of proteins during infection that can potentially disperse systemically in infected plants with the vascular flow. Therefore, their distribution may not be restricted to the pathogen infection sites and could be used as a biological marker for infection. Using mass spectrometry analysis, we identified a unique secreted protein from S. citri that is highly expressed in the presence of citrus phloem extract. ScCCPP1, an antibody generated against this protein, was able to distinguish S. citri-infected citrus and periwinkle from healthy plants. In addition, the antiserum could be used to detect CSD using a simple direct tissue print assay without the need for sample processing or specialized lab equipment and may be suitable for field surveys. This study provides proof of a novel concept of using pathogen-secreted protein as a marker for diagnosis of a citrus bacterial disease and can probably be applied to other plant diseases.

  11. Whole-Genome Sequence of "Candidatus Profftella armatura" from Diaphorina citri in Guangdong, China.

    Science.gov (United States)

    Wu, F; Deng, X; Liang, G; Huang, J; Cen, Y; Chen, J

    2015-01-01

    The genome of "Candidatus Profftella armatura" strain YCPA from Diaphorina citri in Guangdong, China, was sequenced. The strain has a chromosome of 457,565 bp, 24.3% G+C content, 364 predicted open reading frames (ORFs), and 38 RNAs, and a plasmid, pYCPA54, of 5,458 bp with 23.9% G+C content and 5 ORFs. PMID:26543117

  12. Biology of the Huanglongbing vector Diaphorina citri (Hemiptera: Liviidae) on different host plants.

    Science.gov (United States)

    Alves, G R; Diniz, A J F; Parra, J R P

    2014-04-01

    Although many studies have been conducted on the development and reproductive potential of Diaphorina citri Kuwayama, 1908 (Hemiptera: Liviidae) in different host species, few have evaluated these parameters on different varieties of the same host species. This study evaluated the influence of five commercial varieties of citrus (Citrus spp. L.)--Hamlin, Natal, Pêra, Ponkan, and Valencia-and orange jasmine [Murraya exotica (L.) Jack] on the development of D. citri. Survival rates for the egg stage were highest on orange jasmine (85.7%) and on Valencia (83.3%). The lowest viability of the nymphal stage was also observed on Hamlin, averaging 57.4%. Values for total viability ranged from 65.9 to 32.6%, and were highest on Valencia. The longest egg-adult development time was on Natal, with a mean of 18.4 d; the shortest total development time was on orange jasmine, with a mean of 17.3 d. Based on the fertility life table, the net reproductive rate (Ro) of D. citri was 2.5 times higher when reared on Valencia than on Hamlin. The other parameters (duration of each generation [T], finite rate of increase [lambda], and innate capacity to increase in number [r(m)]) also demonstrated that Valencia is best suited to this insect. The results obtained for the biological parameters and the fertility life table indicate that Valencia and orange jasmine were the most suitable hosts, whereas Hamlin was least suitable for the development of D. citri. These results provide information for the installation of new citrus groves, especially in the choice of varieties to be planted and the location of different varieties within the groves, with a view toward the management of Huanglongbing or HLB. PMID:24772551

  13. Adjuvants to improve aerial control of the citrus mealybug Planococcus citri (Hemiptera: Pseudococcidae) using entomopathogenic nematodes.

    Science.gov (United States)

    van Niekerk, S; Malan, A P

    2015-03-01

    The citrus mealybug, Planococcus citri, is a highly destructive pest of citrus, occurring only in the aerial parts of plants. Humidity will be one of the key factors to consider when using entomopathogenic nematodes (EPN) as biological control agents. Different adjuvants can be added to suspensions of EPNs, to improve control as a foliar application. An aqueous suspension containing Heterorhabditis zealandica and 0.3% Zeba® significantly increased P. citri mortality by 22% at 80% relative humidity (RH) with a temperature cycle starting at 22°C for 14 h and 11°C for 11 h. The same polymer formulation was tested for Steinernema yirgalemense and mortality of P. citri increased by 21% at 60% RH and by 27% at 80% RH. The addition of Nu-Film-P® and Zeba® to H. zealandica suspensions did not significantly retard application run-off on citrus leaves. The combination of Nu-Film-P® and Zeba®, however, was able to significantly retard sedimentation, increasing the average number of nematodes deposited on 2-cm2 leaf discs by 10 nematodes. In an aqueous suspension, nematodes settle rapidly to the bottom, resulting in an uneven distribution of nematodes. Xanthan gum, at a concentration of 0.2%, was highly effective at retarding sedimentation, with 72% of the initial nematode number still in suspension after 1 h. Zeba®, at a concentration of 0.3%, despite not being as effective as Xanthan gum, nevertheless still retarded sedimentation significantly. This is the first report of the potential of Nu-Film-P® and Zeba® to improve EPN performance against P. citri when used above ground in citrus orchards.

  14. Whole-Genome Sequence of "Candidatus Profftella armatura" from Diaphorina citri in Guangdong, China.

    Science.gov (United States)

    Wu, F; Deng, X; Liang, G; Huang, J; Cen, Y; Chen, J

    2015-01-01

    The genome of "Candidatus Profftella armatura" strain YCPA from Diaphorina citri in Guangdong, China, was sequenced. The strain has a chromosome of 457,565 bp, 24.3% G+C content, 364 predicted open reading frames (ORFs), and 38 RNAs, and a plasmid, pYCPA54, of 5,458 bp with 23.9% G+C content and 5 ORFs.

  15. Biology of the Huanglongbing vector Diaphorina citri (Hemiptera: Liviidae) on different host plants.

    Science.gov (United States)

    Alves, G R; Diniz, A J F; Parra, J R P

    2014-04-01

    Although many studies have been conducted on the development and reproductive potential of Diaphorina citri Kuwayama, 1908 (Hemiptera: Liviidae) in different host species, few have evaluated these parameters on different varieties of the same host species. This study evaluated the influence of five commercial varieties of citrus (Citrus spp. L.)--Hamlin, Natal, Pêra, Ponkan, and Valencia-and orange jasmine [Murraya exotica (L.) Jack] on the development of D. citri. Survival rates for the egg stage were highest on orange jasmine (85.7%) and on Valencia (83.3%). The lowest viability of the nymphal stage was also observed on Hamlin, averaging 57.4%. Values for total viability ranged from 65.9 to 32.6%, and were highest on Valencia. The longest egg-adult development time was on Natal, with a mean of 18.4 d; the shortest total development time was on orange jasmine, with a mean of 17.3 d. Based on the fertility life table, the net reproductive rate (Ro) of D. citri was 2.5 times higher when reared on Valencia than on Hamlin. The other parameters (duration of each generation [T], finite rate of increase [lambda], and innate capacity to increase in number [r(m)]) also demonstrated that Valencia is best suited to this insect. The results obtained for the biological parameters and the fertility life table indicate that Valencia and orange jasmine were the most suitable hosts, whereas Hamlin was least suitable for the development of D. citri. These results provide information for the installation of new citrus groves, especially in the choice of varieties to be planted and the location of different varieties within the groves, with a view toward the management of Huanglongbing or HLB.

  16. Whole-Genome Sequence of “Candidatus Profftella armatura” from Diaphorina citri in Guangdong, China

    Science.gov (United States)

    Wu, F.; Deng, X.; Huang, J.; Cen, Y.

    2015-01-01

    The genome of “Candidatus Profftella armatura” strain YCPA from Diaphorina citri in Guangdong, China, was sequenced. The strain has a chromosome of 457,565 bp, 24.3% G+C content, 364 predicted open reading frames (ORFs), and 38 RNAs, and a plasmid, pYCPA54, of 5,458 bp with 23.9% G+C content and 5 ORFs. PMID:26543117

  17. Structural and functional analyses of the putrescine binding protein PotF from Xanthomonas citri

    Energy Technology Data Exchange (ETDEWEB)

    Santana, L.D.F.; Balan, A. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil)

    2012-07-01

    Full text: The focus of our group is to determinate the role of ABC transporters in the physiology and growth of Xanthomonas citri, a phytopathogenic bacteria that infects citrus plants causing significant losses for the economy. One of the ABC transporters identified in the X. citri genome and that was showed to be active during the infection in Citrus sinensis plants was the putrescine transporter. This transporter consists of two internal membrane proteins PotG and PotH that form a pore, a cytoplasmic protein that gives energy for the transport and the periplasmic-binding protein PotF, which is responsible for the affinity and specificity of the system. Its function is associated to the microbial carcinogenesis, biofilm formation, escape from phagolysosomes, bacteriocin production, toxin activity and protection from oxidative and acid stress. In this work, we show for the first time, the expression, purification, functional and structural analyses of the X. citri PotF protein. The PotF was expressed from Escherichia coli cells strain Arctic, as a 40 kDa soluble protein, after induction of IPTG for twenty four hours at thirteen deg C. Using immobilized metal affinity chromatography for purification, the protein was eluted in the fractions with 10-500 mM of imidazole. To test the folding and cability to bind putrescine, spectroscopic analyses were performed using circular dichroism and intrinsic fluorescence. The data showed that PotF suffers conformational changes in presence of ligands and in different pH, suggesting a possible interaction with the tested ligand. Moreover, based on bioinformatics studies and molecular modeling analyses, we showed that X. citri PotF is highly conserved when compared to orthologs present in other bacteria, including the residues that form the ligand-binding site. The production of PotF in a soluble and stable form will allow us to start the crystallization trials in attempt to solve its structure. (author)

  18. [Control effects of Mikania micrantha alcohol extract on citrus red mite Panonychus citri].

    Science.gov (United States)

    Cen, Yijing; Pang, Xiongfei; Xu, Changbao; Deng, Qiaosheng

    2005-04-01

    This study showed that spraying 0.2 and 0.4 g x L(-1) Mikania micrantha alcohol extracts on Panonychus citri could significantly decrease the survival rates of P. citri eggs, larvae and nymphs, and 0.1 g x L(-1) M. micrantha alcohol extract could also significantly decrease the survival rates of larvae and nymphs. In a no-choice test, both the fecundity and the longevity of female P. citri fed on the leaves treated with all three test concentrations 0.1, 0.2 and 0.4 g x L(-1) of M. micrantha alcohol extracts were significantly reduced, compared with those fed on alcohol-treated leaves. In a field experiment, the efficacy of M. micrantha alcohol extracts at three test concentrations was compared with water, alcohol, and 15% Pyridaben, an acaricide widely used in commercial control of red mite in sweet orange orchards. The survival rates of P. citri eggs, larvae and nymphs in all three M. micrantha treatments were lower than the control, and the interference index of population control (IIPC) was 0.518, 0.292 and 0.277, respectively, while the IIPC for the Pyridaben treatment was 0.945, with a control efficacy of only 5.52%. M. micrantha extract had an increased control effect with its increasing concentration, and was safer to natural enemies than 15% Pyridaben. The leaves in the three M. micrantha treatments were less damaged, and their color was much deeper than that of the other three treatments. Therefore, M. micrantha alcohol extract provided a better control of citrus red mite populations than Pyridaben. PMID:16011182

  19. Seasonal Population Dynamics of the Asian Citrus Psyllid, Diaphorina citri Kuwayama in Sarawak

    Directory of Open Access Journals (Sweden)

    Stephen L.C. Teck

    2011-01-01

    Full Text Available Problem statement: Effective control of phytophagous pests requires a thorough understanding of their seasonal population dynamics, dispersion behavior, natural enemy activity and climate. To date, although very little detail information had been published on the ecology of Diaphorina citri. The objective of this investigation was to test through field experiment the hypothesis that the major factors influencing local D. citri populations particularly their seasonal population dynamics in Sarawak are (a flushing cycles, (b climate and (c the impact of the primary parasitoids namely Tamarixia radiata and Diaphorencyrtus aligarhensis. Approach: Seasonal abundance D. citri was studied weekly from March 1998 to December 2000 in the 1-ha citrus honey mandarin (Citrus aurantium L. commercial orchard at Jemukan (1° 33'N, 110° 41'E, Kota Samarahan Division, Southwest Sarawak, in Malaysia. Results: Field studies on citrus trees showed that the D. citri population fluctuates throughout the year on citrus honey mandarin in Sarawak. Generations overlapped but adult and egg population peaks for a short period generally coincided with three annual flushing cycles, in August-September, February-March and June-July between March 1998 and December 2000. Conclusion: Psyllid population levels are positively related to the availability of new shoot flushes. Psyllid populations are adversely affected by weather conditions and parasitoids. Adult psyllid populations increased exponentially during periods of flush growth and migration and dispersal of the adults was also related to flushing cycles. Dispersal and colonization of new trees is greatest in September-October, at the onset of the rainy season.

  20. Molecular Effects of Irradiation (Cobalt-60 on the Control of Panonychus citri (Acari: Tetranychidae

    Directory of Open Access Journals (Sweden)

    Ke Zhang

    2015-11-01

    Full Text Available The effective dose of irradiation to control pest mites in quarantine has been studied extensively, but the molecular mechanisms underlying the effects of the irradiation on mites are largely unknown. In this study, exposure to 400 Gy of γ rays had significant (p < 0.05 effects on the adult survival, fecundity and egg viability of Panonychus citri. The irradiation caused the degradation of the DNA of P. citri adults and damaged the plasma membrane system of the egg, which led to condensed nucleoli and gathered yolk. Additionally, the transcriptomes and gene expression profiles between irradiated and non-irradiated mites were compared, and three digital gene expression libraries were assembled and analyzed. The differentially expressed genes were putatively involved in apoptosis, cell death and the cell cycle. Finally, the expression profiles of some related genes were studied using quantitative real-time PCR. Our study provides valuable information on the changes in the transcriptome of irradiated P. citri, which will facilitate a better understanding of the molecular mechanisms that cause the sterility induced by irradiation.

  1. The molybdate-binding protein (ModA) of the plant pathogen Xanthomonas axonopodis pv. citri.

    Science.gov (United States)

    Balan, Andrea; Santacruz, Carolina P; Moutran, Alexandre; Ferreira, Rita C C; Medrano, Francisco J; Pérez, Carlos A; Ramos, Carlos H I; Ferreira, Luís C S

    2006-12-01

    The modABC operon of phytopathogen Xanthomonas axonopodis pv. citri (X. citri) encodes a putative ABC transporter involved in the uptake of the molybdate and tungstate anions. Sequence analyses showed high similarity values of ModA orthologs found in X. campestris pv. campestris (X. campestris) and Escherichia coli. The X. citri modA gene was cloned in pET28a and the recombinant protein, expressed in the E. coli BL21 (DE3) strain, purified by immobilized metal affinity chromatography. The purified protein remained soluble and specifically bound molybdate and tungstate with K(d) 0.29+/-0.12 microM and 0.58+/-0.14 microM, respectively. Additionally binding of molybdate drastically enhanced the thermal stability of the recombinant ModA as compared to the apoprotein. This is the first characterization of a ModA ortholog expressed by a phytopathogen and represents an important tool for functional, biochemical and structural analyses of molybdate transport in Xanthomonas species.

  2. Genetic diversity of Xanthomonas axonopodis pv. citri based on plasmid profile and pulsed field gel electrophoresis

    Directory of Open Access Journals (Sweden)

    Carvalho Flávia Maria de Souza

    2005-01-01

    Full Text Available Xanthomonas axonopodis pv. citri strains that cause disease in citrus were investigated by pulsed field and plasmid profile analysis. For the first method, genomic DNA was digested by the rare-cutting enzymes Xba I and Vsp I. The strains evaluated were collected in seven different States of Brazil and in Argentina, Bolivia, Paraguay and Uruguay. Genetic variability was found among strains of X. axonopodis pv. citri from different geographical areas Argentina, Bolivia and Uruguay, with similarities varying from 0.62 to 0.83. However, the strains collected in Brazil, despite being from different States, have shown a genetic similarity ranging from 0.83 to 1.00. Cluster analysis showed a relationship between genomic similarity and geographical origin of the strains. Plasmids were observed in all strains, with a total of five different plasmids, with sizes between 57.7 and 83.0 kilobases. The 72.6 kb plasmid was the most frequent, present in 15 out of 22 strains, while the 68.1 kb plasmid was observed in two strains only. Although the plasmid diversity detected in the present study was not very great, the X. axonopodis pv. citri strains evaluated showed a considerable degree of diversity with regard to this extrachromosomal genetic element.

  3. Molecular Effects of Irradiation (Cobalt-60) on the Control of Panonychus citri (Acari: Tetranychidae).

    Science.gov (United States)

    Zhang, Ke; Luo, Lingyan; Chen, Xieting; Hu, Meiying; Hu, Qiongbo; Gong, Liang; Weng, Qunfang

    2015-01-01

    The effective dose of irradiation to control pest mites in quarantine has been studied extensively, but the molecular mechanisms underlying the effects of the irradiation on mites are largely unknown. In this study, exposure to 400 Gy of γ rays had significant (p Panonychus citri. The irradiation caused the degradation of the DNA of P. citri adults and damaged the plasma membrane system of the egg, which led to condensed nucleoli and gathered yolk. Additionally, the transcriptomes and gene expression profiles between irradiated and non-irradiated mites were compared, and three digital gene expression libraries were assembled and analyzed. The differentially expressed genes were putatively involved in apoptosis, cell death and the cell cycle. Finally, the expression profiles of some related genes were studied using quantitative real-time PCR. Our study provides valuable information on the changes in the transcriptome of irradiated P. citri, which will facilitate a better understanding of the molecular mechanisms that cause the sterility induced by irradiation. PMID:26569230

  4. Is the old world fig, Ficus carica L. (Moraceae), an alternate host for the Asian citrus psyllid, Diaphorina citri (Kuwayama) (Homoptera: Psyllidae)?

    Science.gov (United States)

    The only non-rutaceous plant on which D. citri has been found breeding in Texas is the edible fig, Ficus carica (Moraceae). In the summer of 2010, we discovered D. citri nymphs on a dooryard fig tree. Fig has its own species of psyllid, Homatoma ficus, but both adults and nymphs of that species ar...

  5. Potential of South African entomopathogenic nematodes (Heterorhabditidae and Steinernematidae) for control of the citrus mealybug, Planococcus citri (Pseudococcidae).

    Science.gov (United States)

    van Niekerk, Sonnica; Malan, Antoinette P

    2012-10-01

    Planococcus citri, the citrus mealybug, is the most important species of mealybug known to infest citrus in South Africa. Various laboratory bioassays were conducted to determine the potential of entomopathogenic nematodes to control P. citri. Adult female P. citri were screened for susceptibility to six indigenous nematode species. P. citri was found to be most susceptible to Steinernema yirgalemense and Heterorhabditis zealandica, causing 97% and 91% mortality, respectively. The development of nematodes after infecting adult female P. citri showed both H. zealandica and S. yirgalemense were able to complete their life cycles inside the host. Further bioassays illustrated a linear relationship between mealybug mortality and the concentration of nematodes applied, with the highest level of control using a concentration of 80 infective juveniles (IJs)/insect. As nematodes would be used as an above-ground application to control P. citri in citrus orchards, available water is a major limiting factor. Insecticidal activity proved to be dependent on the available surface moisture after nematode application. The water activity (a(w)) bioassay indicated that S. yirgalemense to be two times more tolerant to lower levels of free water, with a(w50)=0.96 and a(w90)=0.99, compared to H. zealandica with a(w50)=0.98 and a(w)90=1.0. After application, nematodes have a limited time frame in which to locate and infect hosts, as the level of available free water gradually decreases, as trees dry out. S. yirgalemense proved able to locate and infect P. citri quicker than H. zealandica. Nematode activity was not significantly affected when exposed to 15°C, 20°C and 25°C. IJs were able to infect P. citri at an exposure time as short as half an hour. Results also showed that the first 2-4h post application is the most decisive time for establishing successful infection of mealybugs. This is the first report on the potential use of nematodes for the control of P. citri.

  6. Expression Patterns of Genes Involved in the Defense and Stress Response of Spiroplasma citri Infected Madagascar Periwinkle Catharanthus roseus

    Directory of Open Access Journals (Sweden)

    Naghmeh Nejat

    2012-02-01

    Full Text Available Madagascar periwinkle is an ornamental and a medicinal plant, and is also an indicator plant that is highly susceptible to phytoplasma and spiroplasma infections from different crops. Periwinkle lethal yellows, caused by Spiroplasma citri, is one of the most devastating diseases of periwinkle. The response of plants to S. citri infection is very little known at the transcriptome level. In this study, quantitative real-time PCR (RT-qPCR was used to investigate the expression levels of four selected genes involved in defense and stress responses in naturally and experimentally Spiroplasma citri infected periwinkles. Strictosidine β-glucosidase involved in terpenoid indole alkaloids (TIAs biosynthesis pathway showed significant upregulation in experimentally and naturally infected periwinkles. The transcript level of extensin increased in leaves of periwinkles experimentally infected by S. citri in comparison to healthy ones. A similar level of heat shock protein 90 and metallothionein expression was observed in healthy, naturally and experimentally spiroplasma-diseased periwinkles. Overexpression of Strictosidine β-glucosidase demonstrates the potential utility of this gene as a host biomarker to increase the fidelity of S. citri detection and can also be used in breeding programs to develop stable disease-resistance varieties.

  7. Expression patterns of genes involved in the defense and stress response of Spiroplasma citri infected Madagascar Periwinkle Catharanthus roseus.

    Science.gov (United States)

    Nejat, Naghmeh; Vadamalai, Ganesan; Dickinson, Matthew

    2012-01-01

    Madagascar periwinkle is an ornamental and a medicinal plant, and is also an indicator plant that is highly susceptible to phytoplasma and spiroplasma infections from different crops. Periwinkle lethal yellows, caused by Spiroplasma citri, is one of the most devastating diseases of periwinkle. The response of plants to S. citri infection is very little known at the transcriptome level. In this study, quantitative real-time PCR (RT-qPCR) was used to investigate the expression levels of four selected genes involved in defense and stress responses in naturally and experimentally Spiroplasma citri infected periwinkles. Strictosidine β-glucosidase involved in terpenoid indole alkaloids (TIAs) biosynthesis pathway showed significant upregulation in experimentally and naturally infected periwinkles. The transcript level of extensin increased in leaves of periwinkles experimentally infected by S. citri in comparison to healthy ones. A similar level of heat shock protein 90 and metallothionein expression was observed in healthy, naturally and experimentally spiroplasma-diseased periwinkles. Overexpression of Strictosidine β-glucosidase demonstrates the potential utility of this gene as a host biomarker to increase the fidelity of S. citri detection and can also be used in breeding programs to develop stable disease-resistance varieties.

  8. Analyses of Numerical Responses and Main Life Parameters for Determining the Suppression of Amblyseius cucumeris on Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan-xuan; LIN Jian-zhen; JI Jie; CHEN Xie; KANG Yu-mei

    2005-01-01

    In this paper, the numeral response and main parameters of experimental population life table were analyzed for determiningthe suppressing ability of Amblyseius cucumeris on Panonychus citri. The result showed that: (1) Under 21-31 ℃ and 1-9 prey densities/leaf fragment condition, the prey consumptions ofA. cucumeris increased with the temperature or prey density; (2) In 1:3 predator-prey ratio treatment, the suppression ofP. citri (Ro=34.0053; T=19.4369; t=3.8204) was rather weak, it was enhanced as the ratio over 5:30, and the populations ofP. citri in these treatments can be fully controlled within 4-5 days; (3) Under 25±1℃, 80-85% RH and 15L: 9D illumination conditions, the net reproductive rate, mean generation duration and the time for population double increase ofP. citri (Ro=34.0053; T=19.4369; t=3.8204) were higher than those ofA. cucumeris (Ro=21.8750; T=16.8943; t=3.7954). While the intrinsic rate of increase and finite rate of increase of the former (rm=0.1814; λ= 1.1989) were lower than those of the latter (rm=0.1826; λ= 1.2004). These results indicated that A. cucumeris is a desirable bio-control agent to suppress P. citri at lower population stage in citrus orchard.

  9. Geographic distribution of habitat, development, and population growth rates of the Asian citrus psyllid, Diaphorina citri, in Mexico.

    Science.gov (United States)

    López-Collado, José; Isabel López-Arroyo, J; Robles-García, Pedro L; Márquez-Santos, Magdalena

    2013-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an introduced pest in Mexico and a vector of huanglongbing, a lethal citrus disease. Estimations of the habitat distribution and population growth rates of D. citri are required to establish regional and areawide management strategies and can be used as a pest risk analysis tools. In this study, the habitat distribution of D. citri in Mexico was computed with MaxEnt, an inductive, machine-learning program that uses bioclimatic layers and point location data. Geographic distributions of development and population growth rates were determined by fitting a temperature-dependent, nonlinear model and projecting the rates over the target area, using the annual mean temperature as the predictor variable. The results showed that the most suitable regions for habitat of D. citri comprise the Gulf of Mexico states, Yucatán Peninsula, and areas scattered throughout the Pacific coastal states. Less suitable areas occurred in northern and central states. The most important predictor variables were related to temperature. Development and growth rates had a distribution wider than habitat, reaching some of the northern states of México. Habitat, development, and population growth rates were correlated to each other and with the citrus producing area. These relationships indicated that citrus producing states are within the most suitable regions for the occurrence, development, and population growth of D. citri, therefore increasing the risk of huanglongbing dispersion. PMID:24735280

  10. The effects of host, geographic origin, and gender on the thermal requirements of Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Nava, Dori E; Gomez-Torres, Mariuxi L; Rodrigues, Marjorie D; Bento, José M S; Haddad, Marinéia L; Parra, José R P

    2010-04-01

    Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is the vector of the bacteria that causes citrus greening and is considered one of the world's most important citrus diseases. We examined how host, geographic region, and gender affect the thermal requirements of D. citri. The insects were reared in climatic chambers at constant temperatures of 18, 20, 22, 25, 28, 30, and 32 +/- 1 degrees C, 70 +/- 10% RH, and a 14 h photophase. Host plants for D. citri included orange (Citrus sinensis [Rutaceae]) varieties Pêra and Natal, the rootstock, Rungpur lime (C. limonia [Rutaceae]) and the natural host, Orange jessamine (Murraya paniculata [Rutaceae]). To study the influence of geographic origin on thermal requirements, we studied D. citri populations from Piracicaba, SP (warmer region) and Itapetininga, SP (cooler region). The duration and survival of the development stages and the duration of the total development (egg-adult) did not differ significantly on the different hosts, but it did vary with temperature. Nymphs of D. citri created on the different hosts have the same thermal requirements. The thermal requirements for this species collected from the two climate regions were identical; males and females also had the same thermal requirements.

  11. Morphological and molecular characterization of a Hirsutella species infecting the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), in Florida.

    Science.gov (United States)

    Meyer, Jason M; Hoy, Marjorie A; Boucias, Drion G

    2007-06-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama, is an invasive pest that vectors citrus greening disease, which recently was detected in Florida. Mycosed adult D. citri were collected at four sites in central Florida between September 2005 and February 2006. Observation of the cadavers using scanning electron microscopy revealed that the pathogen had branched synnemata supporting monophiladic conidiogenous cells. A high-fidelity polymerase chain reaction (PCR) assay was used to amplify the 18S rRNA, 28S rRNA and beta-tubulin genes of the pathogen for phylogenetic analysis. The morphological and genetic data indicated that the pathogen was a novel isolate related to Hirsutella citriformis Speare. PCR assays using isolate-specific primers designed from the unique putative intron region of the beta-tubulin sequence distinguished the psyllid pathogen from five related Hirsutella species. The pathogen was maintained in vivo by exposing healthy D. citri to the synnemata borne on field-collected cadavers. Infected psyllids had an abundance of septate hyphal bodies in their hemolymph and exhibited behavioral symptoms of disease. In vitro cultures of the pathogen were slow-growing and produced synnemata similar to those found on mycosed D. citri. In laboratory bioassays, high levels of mortality were observed in D. citri that were exposed to the conidia-bearing synnemata produced in vivo and in vitro.

  12. Geographic distribution of habitat, development, and population growth rates of the Asian citrus psyllid, Diaphorina citri, in Mexico.

    Science.gov (United States)

    López-Collado, José; Isabel López-Arroyo, J; Robles-García, Pedro L; Márquez-Santos, Magdalena

    2013-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an introduced pest in Mexico and a vector of huanglongbing, a lethal citrus disease. Estimations of the habitat distribution and population growth rates of D. citri are required to establish regional and areawide management strategies and can be used as a pest risk analysis tools. In this study, the habitat distribution of D. citri in Mexico was computed with MaxEnt, an inductive, machine-learning program that uses bioclimatic layers and point location data. Geographic distributions of development and population growth rates were determined by fitting a temperature-dependent, nonlinear model and projecting the rates over the target area, using the annual mean temperature as the predictor variable. The results showed that the most suitable regions for habitat of D. citri comprise the Gulf of Mexico states, Yucatán Peninsula, and areas scattered throughout the Pacific coastal states. Less suitable areas occurred in northern and central states. The most important predictor variables were related to temperature. Development and growth rates had a distribution wider than habitat, reaching some of the northern states of México. Habitat, development, and population growth rates were correlated to each other and with the citrus producing area. These relationships indicated that citrus producing states are within the most suitable regions for the occurrence, development, and population growth of D. citri, therefore increasing the risk of huanglongbing dispersion.

  13. Expression Patterns of Genes Involved in the Defense and Stress Response of Spiroplasma citri Infected Madagascar Periwinkle Catharanthus roseus

    Science.gov (United States)

    Nejat, Naghmeh; Vadamalai, Ganesan; Dickinson, Matthew

    2012-01-01

    Madagascar periwinkle is an ornamental and a medicinal plant, and is also an indicator plant that is highly susceptible to phytoplasma and spiroplasma infections from different crops. Periwinkle lethal yellows, caused by Spiroplasma citri, is one of the most devastating diseases of periwinkle. The response of plants to S. citri infection is very little known at the transcriptome level. In this study, quantitative real-time PCR (RT-qPCR) was used to investigate the expression levels of four selected genes involved in defense and stress responses in naturally and experimentally Spiroplasma citri infected periwinkles. Strictosidine β-glucosidase involved in terpenoid indole alkaloids (TIAs) biosynthesis pathway showed significant upregulation in experimentally and naturally infected periwinkles. The transcript level of extensin increased in leaves of periwinkles experimentally infected by S. citri in comparison to healthy ones. A similar level of heat shock protein 90 and metallothionein expression was observed in healthy, naturally and experimentally spiroplasma-diseased periwinkles. Overexpression of Strictosidine β-glucosidase demonstrates the potential utility of this gene as a host biomarker to increase the fidelity of S. citri detection and can also be used in breeding programs to develop stable disease-resistance varieties. PMID:22408455

  14. Transcriptome analysis of the citrus red mite, Panonychus citri, and its gene expression by exposure to insecticide/acaricide.

    Science.gov (United States)

    Niu, J-Z; Dou, W; Ding, T-B; Shen, G-M; Zhang, K; Smagghe, G; Wang, J-J

    2012-08-01

    The citrus red mite, Panonychus citri, is known for its ability rapidly to evolve resistance to insecticides/acaricides and to adapt to hosts that produce toxins. In this study, we constructed an unprecedented four gigabase pair transcriptome of P. citri, which was assembled into 64 149 unique transcripts, the functions of which were annotated by five public databases. A total of 116 unique transcripts were identified as representatives of potential involvement in the detoxification of xenobiotics. Genes recorded to encoding insecticide/acaricide target proteins were also obtained from the P. citri transcriptome. In order to explore novel candidate genes potentially involved in the pesticide detoxification of P. citri, we also constructed digital gene expression libraries of short-term transcriptome responses of P. citri to pesticides, which resulted in the identification of 120 unique transcripts potentially associated with insecticide/acaricide detoxification. Our study will facilitate molecular research on pesticide resistance in citrus red mites, as well as in other phytophagous mites. PMID:22676046

  15. Olfactory Responses of the Asiatic Citrus Psyllid (Diaphorina citri to Mineral Oil-Treated Mandarin Leaves

    Directory of Open Access Journals (Sweden)

    Mofit E. Poerwanto

    2012-01-01

    Full Text Available Problem statement: Evidence of rejection or acceptance by phytophagous pests of citrus plants treated with mineral oils suggests that impacts of oils may be related to detection by olfactory and/or contact chemoreceptors of repellent oils or plant volatiles. Alternatively, the oils may mask or suppress attractant host plant volatiles. To date, no studies have reported that oils elicit an olfactory response in Diaphorina citri Kuwayama [Hemiptera: Psyllidae]. Therefore, we undertook two studies to determine how oil deposits on citrus leaves influenced the behaviour of D. citri. Approach: The attractiveness of citrus leaves treated separately with an nC21 horticultural mineral oil and an nC24 agricultural mineral oil to D. citri was evaluated under laboratory conditions. In the first of two studies, the oils were applied as 0.5% aqueous emulsions to mandarin leaves and responses of adults determined after they walked on surfaces saturated with either distilled water or 2% aqueous emulsions of the oils. In the second study, responses of adult psyllids to host-leaf volatiles, mineral oil volatiles emanating from leaves dipped in 2% v/v aqueous emulsions of each oil and similarly treated filter paper paired with water-dipped leaves were determined in single, linear-tube olfactometers. Results: In the first study, deposits of both oils significantly reduced the proportion of D. citri attracted to citrus leaves. Prior exposure of the insects to oil deposits did not influence this response. However, prior contact with the HMO slightly reduced the proportion of psyllids alighting on the water-dipped leaves. In the second study, oil volatiles emanating from filter paper significantly reduced the attractiveness of water-dipped mandarin leaves. Conclusion: These results indicate that application of the oils to the mandarin leaves may have: (a suppressed release of attractant host plant volatiles; (b masked attractant host plant volatiles; (c led to the

  16. Novel insights into the genomic basis of citrus canker based on the genome sequences of two strains of Xanthomonas fuscans subsp. aurantifolii

    OpenAIRE

    Nociti Letícia A; Rodrigues Neto Julio; Leite Rui P; Nishiyama Milton Y; Laia Marcelo L; Kitajima Elliot W.; Jones Jeffrey B; Gimenez Daniele F; Furlan Luiz R; Ferro Maria I; Ferraz André L; Facincani Agda P; de Souza Robson F; de Oliveira Julio C; de Moraes Fabrício E

    2010-01-01

    Abstract Background Citrus canker is a disease that has severe economic impact on the citrus industry worldwide. There are three types of canker, called A, B, and C. The three types have different phenotypes and affect different citrus species. The causative agent for type A is Xanthomonas citri subsp. citri, whose genome sequence was made available in 2002. Xanthomonas fuscans subsp. aurantifolii strain B causes canker B and Xanthomonas fuscans subsp. aurantifolii strain C causes canker C. R...

  17. Essential Oil Variation from Twenty Two Genotypes of Citrus in Brazil-Chemometric Approach and Repellency Against Diaphorina citri Kuwayama.

    Science.gov (United States)

    Andrade, Moacir Dos Santos; Ribeiro, Leandro do Prado; Borgoni, Paulo Cesar; Silva, Maria Fátima das Graças Fernandes da; Forim, Moacir Rossi; Fernandes, João Batista; Vieira, Paulo Cezar; Vendramin, José Djair; Machado, Marcos Antônio

    2016-01-01

    The chemical composition of volatile oils from 22 genotypes of Citrus and related genera was poorly differentiated, but chemometric techniques have clarified the relationships between the 22 genotypes, and allowed us to understand their resistance to D. citri. The most convincing similarities include the synthesis of (Z)-β-ocimene and (E)-caryophyllene for all 11 genotypes of group A. Genotypes of group B are not uniformly characterized by essential oil compounds. When stimulated with odor sources of 22 genotypes in a Y-tube olfactometer D. citri preferentially entered the arm containing the volatile oils of Murraya paniculata, confirming orange jasmine as its best host. C. reticulata × C. sinensis was the least preferred genotype, and is characterized by the presence of phytol, (Z)-β-ocimene, and β-elemene, which were not found in the most preferred genotype. We speculate that these three compounds may act as a repellent, making these oils less attractive to D. citri. PMID:27338332

  18. Evaluation of efficacy of 18 strains of entomopathogenic nematodes (Rhabditida) against Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) under laboratory conditions.

    Science.gov (United States)

    Barbosa Negrisoli, Carla Ruth de Carvalho; Negrisoli Júnior, Aldomario Santo; Botton, Marcos; Garcia, Mauro Silveira; Bernardi, Daniel

    2013-07-01

    Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) is an important plant virus vector in grapevine crops in Brazil and other countries. The mealybug grows in roots and leaves of the grapes. Entomopathogenic nematodes (EPNs) are efficient control agents against insects associated to the soil and could be applied with the same equipment used for chemical insecticides. The aim of this study was to select effective EPNs for controlling P. citri females in laboratory conditions (25±1°C, UR 60±10%). We tested 17 native [Steinernema rarum (6 strains), Steinernema glaseri, Steinernema feltiae, Steinernema riobrave, Steinernema sp., Heterorhabditis bacteriophora (7 strains)] and only one exotic strain (Steinernema carpocapsae ALL). The bioassays were done on Petri dishes infested with females of P. citri, which were sprayed with EPNs juveniles. The strain with larger pathogenicity and virulence in laboratory was H. bacteriophora RS33 (from 69.0% to 92.2% of mortality), native of Rio Grande do Sul.

  19. Essential Oil Variation from Twenty Two Genotypes of Citrus in Brazil-Chemometric Approach and Repellency Against Diaphorina citri Kuwayama.

    Science.gov (United States)

    Andrade, Moacir Dos Santos; Ribeiro, Leandro do Prado; Borgoni, Paulo Cesar; Silva, Maria Fátima das Graças Fernandes da; Forim, Moacir Rossi; Fernandes, João Batista; Vieira, Paulo Cezar; Vendramin, José Djair; Machado, Marcos Antônio

    2016-01-01

    The chemical composition of volatile oils from 22 genotypes of Citrus and related genera was poorly differentiated, but chemometric techniques have clarified the relationships between the 22 genotypes, and allowed us to understand their resistance to D. citri. The most convincing similarities include the synthesis of (Z)-β-ocimene and (E)-caryophyllene for all 11 genotypes of group A. Genotypes of group B are not uniformly characterized by essential oil compounds. When stimulated with odor sources of 22 genotypes in a Y-tube olfactometer D. citri preferentially entered the arm containing the volatile oils of Murraya paniculata, confirming orange jasmine as its best host. C. reticulata × C. sinensis was the least preferred genotype, and is characterized by the presence of phytol, (Z)-β-ocimene, and β-elemene, which were not found in the most preferred genotype. We speculate that these three compounds may act as a repellent, making these oils less attractive to D. citri.

  20. Structural and Physiological Analyses of the Alkanesulphonate-Binding Protein (SsuA) of the Citrus Pathogen Xanthomonas citri

    Science.gov (United States)

    Tófoli de Araújo, Fabiano; Bolanos-Garcia, Victor M.; Pereira, Cristiane T.; Sanches, Mario; Oshiro, Elisa E.; Ferreira, Rita C. C.; Chigardze, Dimitri Y.; Barbosa, João Alexandre Gonçalves; de Souza Ferreira, Luís Carlos; Benedetti, Celso E.; Blundell, Tom L.; Balan, Andrea

    2013-01-01

    Background The uptake of sulphur-containing compounds plays a pivotal role in the physiology of bacteria that live in aerobic soils where organosulfur compounds such as sulphonates and sulphate esters represent more than 95% of the available sulphur. Until now, no information has been available on the uptake of sulphonates by bacterial plant pathogens, particularly those of the Xanthomonas genus, which encompasses several pathogenic species. In the present study, we characterised the alkanesulphonate uptake system (Ssu) of Xanthomonas axonopodis pv. citri 306 strain (X. citri), the etiological agent of citrus canker. Methodology/Principal Findings A single operon-like gene cluster (ssuEDACB) that encodes both the sulphur uptake system and enzymes involved in desulphurisation was detected in the genomes of X. citri and of the closely related species. We characterised X. citri SsuA protein, a periplasmic alkanesulphonate-binding protein that, together with SsuC and SsuB, defines the alkanesulphonate uptake system. The crystal structure of SsuA bound to MOPS, MES and HEPES, which is herein described for the first time, provides evidence for the importance of a conserved dipole in sulphate group coordination, identifies specific amino acids interacting with the sulphate group and shows the presence of a rather large binding pocket that explains the rather wide range of molecules recognised by the protein. Isolation of an isogenic ssuA-knockout derivative of the X. citri 306 strain showed that disruption of alkanesulphonate uptake affects both xanthan gum production and generation of canker lesions in sweet orange leaves. Conclusions/Significance The present study unravels unique structural and functional features of the X. citri SsuA protein and provides the first experimental evidence that an ABC uptake system affects the virulence of this phytopathogen. PMID:24282519

  1. Structural and physiological analyses of the alkanesulphonate-binding protein (SsuA of the citrus pathogen Xanthomonas citri.

    Directory of Open Access Journals (Sweden)

    Fabiano Tófoli de Araújo

    Full Text Available BACKGROUND: The uptake of sulphur-containing compounds plays a pivotal role in the physiology of bacteria that live in aerobic soils where organosulfur compounds such as sulphonates and sulphate esters represent more than 95% of the available sulphur. Until now, no information has been available on the uptake of sulphonates by bacterial plant pathogens, particularly those of the Xanthomonas genus, which encompasses several pathogenic species. In the present study, we characterised the alkanesulphonate uptake system (Ssu of Xanthomonas axonopodis pv. citri 306 strain (X. citri, the etiological agent of citrus canker. METHODOLOGY/PRINCIPAL FINDINGS: A single operon-like gene cluster (ssuEDACB that encodes both the sulphur uptake system and enzymes involved in desulphurisation was detected in the genomes of X. citri and of the closely related species. We characterised X. citri SsuA protein, a periplasmic alkanesulphonate-binding protein that, together with SsuC and SsuB, defines the alkanesulphonate uptake system. The crystal structure of SsuA bound to MOPS, MES and HEPES, which is herein described for the first time, provides evidence for the importance of a conserved dipole in sulphate group coordination, identifies specific amino acids interacting with the sulphate group and shows the presence of a rather large binding pocket that explains the rather wide range of molecules recognised by the protein. Isolation of an isogenic ssuA-knockout derivative of the X. citri 306 strain showed that disruption of alkanesulphonate uptake affects both xanthan gum production and generation of canker lesions in sweet orange leaves. CONCLUSIONS/SIGNIFICANCE: The present study unravels unique structural and functional features of the X. citri SsuA protein and provides the first experimental evidence that an ABC uptake system affects the virulence of this phytopathogen.

  2. Desenvolvimento de Planococcus citri (Risso, 1813 (Hemiptera: Pseudococcidae em cafeeiros = Development of Planococcus citri (Risso, 1813 (Hemiptera: Pseudococcidae in coffee trees

    Directory of Open Access Journals (Sweden)

    Lenira Viana Costa Santa-Cecília

    2009-01-01

    Full Text Available A cochonilha Planococcus citri (Risso, 1813 suga a seiva dos botões florais e frutos do cafeeiro, atacando as rosetas desde a floração até a colheita. Embora seja relatada há alguns anos na cafeicultura, são escassas as informações sobre o desenvolvimento dessacochonilha em cafeeiros. Assim, o presente trabalho teve por objetivos avaliar alguns aspectos biológicos da fase ninfal de P. citri em plantas de café. Ovos dessa cochonilha foram retirados de uma criação em laboratório, isolados em placas de Petri contendo discos foliares de Coffea arabica L., das cultivares Acaiá Cerrado, Mundo Novo e Catuaí Vermelho e de C. canephora Pierre & Froenher, cultivar Apoatã. As placas foram mantidas em câmara climatizada a 25 ± 1°C, 70 ± 10% de umidade relativa e 12h de fotofase. Constatou-se que a cultivar Catuaí Vermelho foi a que proporcionou maior duração do período ninfal das fêmeas, porém, não foram constatadas diferenças na mortalidade. Essa cochonilha se desenvolveu satisfatoriamente em todas as cultivares de café estudadas e os resultados não mostraram diferenças claras de susceptibilidade.The citrus mealybug Planococcus citri (Risso, 1813 feeds mainly on flowers and fruits of coffee plants from blooming until harvest. Little is known about its development in coffee although its occurrence is already known for several years. This work aims to study the nymph development of this mealybug in coffee plants.Eggs were isolated from a stock culture kept in laboratory and placed inside Petri dishes containing leaf sections in agar. The tested cultivars were Acaia Cerrado, Mundo Novo, Catuai Vermelho (Coffea arabica and Apoatã (C. canephora. Insects were kept in a climatizedchamber at 25ºC, 70 ± 10% humidity and 12-hour photophase. The longest development period in females was obtained in cultivar Catuai Vermelho. No differences in mortality were found among cultivars. Mealybugs developed in all cultivars and the results

  3. PENDIDIKAN DAN PELATIHAN PENGENDALIAN KUTU LONCAT JERUK (Diaphorina citri Kuwayama SEBAGAI HAMA DAN VEKTOR PENYAKIT CVPD DI DESA TARO, GIANYAR

    Directory of Open Access Journals (Sweden)

    Wijaya I N.

    2012-10-01

    Full Text Available Training on jumping plantlice of citrus (Diaphorina citri Kuw the vector of CVPD (Citrus Vein Phloem Degeneration has been held at Taro village, Gianyar regency on 30st July 2012. The activities aimed to know bioecology of D. citri, the vector of CVPD. The training was attended by 32 participants from local farmer groups of Taro village. The method used in activities were lectures, demontration and practical in the citrus field. All participants participited anthusiastically and hope the have the next intensive traning of the citrus culture.

  4. The abundant extrachromosomal DNA content of the Spiroplasma citri GII3-3X genome

    Directory of Open Access Journals (Sweden)

    Carrère Sébastien

    2008-04-01

    Full Text Available Abstract Background Spiroplama citri, the causal agent of citrus stubborn disease, is a bacterium of the class Mollicutes and is transmitted by phloem-feeding leafhopper vectors. In order to characterize candidate genes potentially involved in spiroplasma transmission and pathogenicity, the genome of S. citri strain GII3-3X is currently being deciphered. Results Assembling 20,000 sequencing reads generated seven circular contigs, none of which fit the 1.8 Mb chromosome map or carried chromosomal markers. These contigs correspond to seven plasmids: pSci1 to pSci6, with sizes ranging from 12.9 to 35.3 kbp and pSciA of 7.8 kbp. Plasmids pSci were detected as multiple copies in strain GII3-3X. Plasmid copy numbers of pSci1-6, as deduced from sequencing coverage, were estimated at 10 to 14 copies per spiroplasma cell, representing 1.6 Mb of extrachromosomal DNA. Genes encoding proteins of the TrsE-TraE, Mob, TraD-TraG, and Soj-ParA protein families were predicted in most of the pSci sequences, in addition to members of 14 protein families of unknown function. Plasmid pSci6 encodes protein P32, a marker of insect transmissibility. Plasmids pSci1-5 code for eight different S. citri adhesion-related proteins (ScARPs that are homologous to the previously described protein P89 and the S. kunkelii SkARP1. Conserved signal peptides and C-terminal transmembrane alpha helices were predicted in all ScARPs. The predicted surface-exposed N-terminal region possesses the following elements: (i 6 to 8 repeats of 39 to 42 amino acids each (sarpin repeats, (ii a central conserved region of 330 amino acids followed by (iii a more variable domain of about 110 amino acids. The C-terminus, predicted to be cytoplasmic, consists of a 27 amino acid stretch enriched in arginine and lysine (KR and an optional 23 amino acid stretch enriched in lysine, aspartate and glutamate (KDE. Plasmids pSci mainly present a linear increase of cumulative GC skew except in regions presenting

  5. Involvement of Three Esterase Genes from Panonychus citri (McGregor) in Fenpropathrin Resistance

    Science.gov (United States)

    Shen, Xiao-Min; Liao, Chong-Yu; Lu, Xue-Ping; Wang, Zhe; Wang, Jin-Jun; Dou, Wei

    2016-01-01

    The citrus red mite, Panonychus citri (McGregor), is a major citrus pest with a worldwide distribution and an extensive record of pesticide resistance. However, the underlying molecular mechanism associated with fenpropathrin resistance in this species have not yet been reported. In this study, synergist triphenyl phosphate (TPP) dramatically increased the toxicity of fenpropathrin, suggesting involvement of carboxylesterases (CarEs) in the metabolic detoxification of this insecticide. The subsequent spatiotemporal expression pattern analysis of PcE1, PcE7 and PcE9 showed that three CarEs genes were all over-expressed after insecticide exposure and higher transcripts levels were observed in different field resistant strains of P. citri. Heterologous expression combined with 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetra-zolium bromide (MTT) cytotoxicity assay in Spodoptera frugiperda (Sf9) cells revealed that PcE1-, PcE7- or PcE9-expressing cells showed significantly higher cytoprotective capability than parental Sf9 cells against fenpropathrin, demonstrating that PcEs probably detoxify fenpropathrin. Moreover, gene silencing through the method of leaf-mediated dsRNA feeding followed by insecticide bioassay increased the mortalities of fenpropathrin-treated mites by 31% (PcE1), 27% (PcE7) and 22% (PcE9), respectively, after individual PcE gene dsRNA treatment. In conclusion, this study provides evidence that PcE1, PcE7 and PcE9 are functional genes mediated in fenpropathrin resistance in P. citri and enrich molecular understanding of CarEs during the resistance development of the mite. PMID:27548163

  6. Involvement of Three Esterase Genes from Panonychus citri (McGregor) in Fenpropathrin Resistance.

    Science.gov (United States)

    Shen, Xiao-Min; Liao, Chong-Yu; Lu, Xue-Ping; Wang, Zhe; Wang, Jin-Jun; Dou, Wei

    2016-01-01

    The citrus red mite, Panonychus citri (McGregor), is a major citrus pest with a worldwide distribution and an extensive record of pesticide resistance. However, the underlying molecular mechanism associated with fenpropathrin resistance in this species have not yet been reported. In this study, synergist triphenyl phosphate (TPP) dramatically increased the toxicity of fenpropathrin, suggesting involvement of carboxylesterases (CarEs) in the metabolic detoxification of this insecticide. The subsequent spatiotemporal expression pattern analysis of PcE1, PcE7 and PcE9 showed that three CarEs genes were all over-expressed after insecticide exposure and higher transcripts levels were observed in different field resistant strains of P. citri. Heterologous expression combined with 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetra-zolium bromide (MTT) cytotoxicity assay in Spodoptera frugiperda (Sf9) cells revealed that PcE1-, PcE7- or PcE9-expressing cells showed significantly higher cytoprotective capability than parental Sf9 cells against fenpropathrin, demonstrating that PcEs probably detoxify fenpropathrin. Moreover, gene silencing through the method of leaf-mediated dsRNA feeding followed by insecticide bioassay increased the mortalities of fenpropathrin-treated mites by 31% (PcE1), 27% (PcE7) and 22% (PcE9), respectively, after individual PcE gene dsRNA treatment. In conclusion, this study provides evidence that PcE1, PcE7 and PcE9 are functional genes mediated in fenpropathrin resistance in P. citri and enrich molecular understanding of CarEs during the resistance development of the mite. PMID:27548163

  7. Life table of Tamarixia radiata (Hymenoptera: Eulophidae) on Diaphorina citri (Hemiptera: Psyllidae) at different temperatures.

    Science.gov (United States)

    Gómez-Torres, Mariuxi Lorena; Nava, Dori Edson; Parra, José Roberto Postali

    2012-04-01

    Tamarixia radiata (Waterston, 1922) is the main parasitoid of Diaphorina citri (Kuwayama, 1907), and has been used in classical biological control programs in several countries. The current study investigated the biology and determined the fertility life table of T. radiata in different temperatures, to obtain information to support the establishment of a biological control program for D. citri in Brazil. Fifth-instar nymphs of D. citri were offered to females of T. radiata for parasitism, for 24 h. Then, the parasitoid was removed and the nymphs were placed in incubators at 15, 20, 25, 30, or 35 +/- 1 degrees C, 70 +/- 10% RH, and a 14-h photophase. The percentages of parasitism and emergence, the sex ratio, and the preimaginal period of T. radiata were determined. The fertility life table was developed from the biological data. The highest parasitism rate (77.24%) was obtained at a temperature of 26.3 degrees C, and the lowest parasitism rates occurred at 15 and 35 degrees C (23.1 and 40.2%, respectively). The highest percentages of emergence of the parasitoid occurred at 25, 30, and 35 degrees C (86.7, 88.3, and 78.8%, respectively), with the calculated peak at 30.8 degrees C (89.90%). The duration of the preimaginal developmental period for both females and males of T. radiata was inversely proportional to temperature in the thermal range of 15-35 degrees C. The development of T. radiata occurred at all temperatures studied, and the highest viability of the preimaginal period occurred at 25 degrees C. The highest values of net reproductive rate and finite growth ratio (lambda) were observed at 25 degrees C, so that in each generation the population of T. radiata increased 126.79 times, higher than the values obtained at the other temperatures.

  8. Involvement of Three Esterase Genes from Panonychus citri (McGregor) in Fenpropathrin Resistance.

    Science.gov (United States)

    Shen, Xiao-Min; Liao, Chong-Yu; Lu, Xue-Ping; Wang, Zhe; Wang, Jin-Jun; Dou, Wei

    2016-08-19

    The citrus red mite, Panonychus citri (McGregor), is a major citrus pest with a worldwide distribution and an extensive record of pesticide resistance. However, the underlying molecular mechanism associated with fenpropathrin resistance in this species have not yet been reported. In this study, synergist triphenyl phosphate (TPP) dramatically increased the toxicity of fenpropathrin, suggesting involvement of carboxylesterases (CarEs) in the metabolic detoxification of this insecticide. The subsequent spatiotemporal expression pattern analysis of PcE1, PcE7 and PcE9 showed that three CarEs genes were all over-expressed after insecticide exposure and higher transcripts levels were observed in different field resistant strains of P. citri. Heterologous expression combined with 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetra-zolium bromide (MTT) cytotoxicity assay in Spodoptera frugiperda (Sf9) cells revealed that PcE1-, PcE7- or PcE9-expressing cells showed significantly higher cytoprotective capability than parental Sf9 cells against fenpropathrin, demonstrating that PcEs probably detoxify fenpropathrin. Moreover, gene silencing through the method of leaf-mediated dsRNA feeding followed by insecticide bioassay increased the mortalities of fenpropathrin-treated mites by 31% (PcE1), 27% (PcE7) and 22% (PcE9), respectively, after individual PcE gene dsRNA treatment. In conclusion, this study provides evidence that PcE1, PcE7 and PcE9 are functional genes mediated in fenpropathrin resistance in P. citri and enrich molecular understanding of CarEs during the resistance development of the mite.

  9. Involvement of Three Esterase Genes from Panonychus citri (McGregor in Fenpropathrin Resistance

    Directory of Open Access Journals (Sweden)

    Xiao-Min Shen

    2016-08-01

    Full Text Available The citrus red mite, Panonychus citri (McGregor, is a major citrus pest with a worldwide distribution and an extensive record of pesticide resistance. However, the underlying molecular mechanism associated with fenpropathrin resistance in this species have not yet been reported. In this study, synergist triphenyl phosphate (TPP dramatically increased the toxicity of fenpropathrin, suggesting involvement of carboxylesterases (CarEs in the metabolic detoxification of this insecticide. The subsequent spatiotemporal expression pattern analysis of PcE1, PcE7 and PcE9 showed that three CarEs genes were all over-expressed after insecticide exposure and higher transcripts levels were observed in different field resistant strains of P. citri. Heterologous expression combined with 3-(4,5-dimethyl-thiazol-2-yl-2,5-diphenyltetra-zolium bromide (MTT cytotoxicity assay in Spodoptera frugiperda (Sf9 cells revealed that PcE1-, PcE7- or PcE9-expressing cells showed significantly higher cytoprotective capability than parental Sf9 cells against fenpropathrin, demonstrating that PcEs probably detoxify fenpropathrin. Moreover, gene silencing through the method of leaf-mediated dsRNA feeding followed by insecticide bioassay increased the mortalities of fenpropathrin-treated mites by 31% (PcE1, 27% (PcE7 and 22% (PcE9, respectively, after individual PcE gene dsRNA treatment. In conclusion, this study provides evidence that PcE1, PcE7 and PcE9 are functional genes mediated in fenpropathrin resistance in P. citri and enrich molecular understanding of CarEs during the resistance development of the mite.

  10. A survey of FLS2 genes from multiple citrus species identifies candidates for enhancing disease resistance to Xanthomonas citri ssp. citri.

    Science.gov (United States)

    Shi, Qingchun; Febres, Vicente J; Jones, Jeffrey B; Moore, Gloria A

    2016-01-01

    Pathogen-associated molecular patterns (PAMPs)-triggered immunity (PTI) is an important component of plant innate immunity. In a previous study, we showed that the PAMP flg22 from Xanthomonas citri ssp. citri (Xflg22), the causal agent of citrus canker, induced PTI in citrus, which correlated with the observed levels of canker resistance. Here, we identified and sequenced two bacterial flagellin/flg22 receptors (FLS2-1 and FLS2-2) from 'Duncan' grapefruit (Citrus paradisi, CpFLS2-1 and CpFLS2-2) and 'Sun Chu Sha' mandarin (C. reticulata, CrFLS2-1 and CrFLS2-2). We were able to isolate only one FLS2 from 'Nagami' kumquat (Fortunella margarita, FmFLS2-1) and gene flanking sequences suggest a rearrangement event that resulted in the deletion of FLS2-2 from the genome. Phylogenetic analysis, gene structure and presence of critical amino acid domains all indicate we identified the true FLS2 genes in citrus. FLS2-2 was more transcriptionally responsive to Xflg22 than FLS2-1, with induced expression levels higher in canker-resistant citrus than in susceptible ones. Interestingly, 'Nagami' kumquat showed the highest FLS2-1 steady-state expression levels, although it was not induced by Xflg22. We selected FmFLS2-1, CrFLS2-2 and CpFLS2-2 to further evaluate their capacity to enhance bacterial resistance using Agrobacterium-mediated transient expression assays. Both FmFLS2-1 and CrFLS2-2, the two proteins from canker-resistant species, conferred stronger Xflg22 responses and reduced canker symptoms in leaves of the susceptible grapefruit genotype. These two citrus genes will be useful resources to enhance PTI and achieve resistance against canker and possibly other bacterial pathogens in susceptible citrus types. PMID:27222722

  11. Responsiveness of different citrus genotypes to the Xanthomonas citri ssp. citri-derived pathogen-associated molecular pattern (PAMP) flg22 correlates with resistance to citrus canker.

    Science.gov (United States)

    Shi, Qingchun; Febres, Vicente J; Jones, Jeffrey B; Moore, Gloria A

    2015-06-01

    The bacterial agent of citrus canker disease (Xanthomonas citri ssp. citri, Xcc) has caused tremendous economic losses to the citrus industry around the world. Pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) is important to plant immunity. In this study, we compared the defence responses of citrus canker-resistant and citrus canker-susceptible genotypes to the Xcc-derived PAMP flg22 (Xflg22) by analysing the expression of 20 citrus defence-associated genes. We showed that, in the most resistant genotype, 'Nagami' kumquat, there was significant induction of several defence genes (EDS1, NDR1, PBS1, RAR1, SGT1, PAL1, NPR2 and NPR3) as early as 6 h and up to 72 h after Xflg22 treatment. At the other end of the spectrum, highly susceptible 'Duncan' grapefruit showed no induction of the same defence genes, even 120 h after treatment. Citrus genotypes with partial levels of resistance showed intermediate levels of transcriptional reprogramming that correlated with their resistance level. Xflg22 also triggered a rapid oxidative burst in all genotypes which was higher and accompanied by the induction of PTI marker genes (WRKY22 and GST1) only in the more resistant genotypes. Pretreatment with Xflg22 prior to Xcc inoculation inhibited bacterial growth in kumquat, but not in grapefruit. A flagellin-deficient Xcc strain (XccΔfliC) showed greater growth increase relative to wild-type Xcc in kumquat than in grapefruit. Taken together, our results indicate that Xflg22 initiates strong PTI in canker-resistant genotypes, but not in susceptible ones, and that a robust induction of PTI is an important component of citrus resistance to canker.

  12. RESEARCH ON MATERIAL MEDICA OF PERICARPIUM CITRI RETICULATAE%陈皮本草考证

    Institute of Scientific and Technical Information of China (English)

    魏莹; 杨安金; 骆利平; 李正红; 龚千锋; 杨武亮

    2013-01-01

    The research on the origin of pericarpium citri reticulatae’s name, the variety, the geo-herbalism and the effect was done through looking up Chinese ancient agrostology and modern literatures. The results showed that the name of pericarpium citri reticulatae was based on some certain literatures such as China pharmacopoeia. Therefore, it is reasonable that Citrus reticulate Blanco was formally loaded into China pharmacopoeia published in 2010. Material medica had recorded that pericarpium citri reticulatae coming from Xinhui, Guangdong Province was better. So the current genuine producing areas and the effect were the same basically. There are many arguments on whether tangerine peel needs to be kept and how long it was kept all the time. The aim of this study was to expect to provide basis for material medica for the further clinical application of pericarpium citri reticulatae.%通过查阅古代本草并且结合近现代文献对陈皮名称源流、品种、道地性、功效主治进行考证,结果发现:历版中国药典均以陈皮为正名具有文献依据;2010版药典将陈皮Citrus reticulata Blanco作为正品收载使用具有一定道理;本草记载的陈皮以广东新会为胜,这与现在陈皮的道地产区相吻合;功效主治与目前基本一致。从古至今对陈皮是否存放;若需存放,存放时间这一问题多有争议。本研究对这一问题提出自己的看法,以期对陈皮的进一步临床应用提供本草依据。

  13. Diversidad de diaphorina citri (hemiptera: psyllidae) en dos zonas de colombia

    OpenAIRE

    Moncayo Donoso, Miguel A; Caicedo Vallejo, Ana Milena; Carabalí Muñoz, Arturo; Montoya Lerma, James; Amanza Pinzón, Marta Isabel; Muñoz Florez, Jaime Eduardo

    2014-01-01

    El psílido asiático de los cítricos (Diaphorina citri) se encuentra ampliamente distribuido en regiones tropicales y subtropicales de Asia. Se desarrolla exclusivamente en plantas de la familia Rutaceae, de los géneros Citrus y Murraya y las especies Swinglea glutinosa Murray, Limonia acidissima L. y Citropsis schweinfurthii Swingle y Kellerm. Es importante por transmitir la bacteria que causa la enfermedad del enverdecimiento o greening (en inglés), además ocasiona daño en los brotes nuevos ...

  14. Partial Purification and Properties of a Cysteine Protease from Citrus Red Mite Panonychus citri

    OpenAIRE

    Hong, Seong Chul; Her, Kyu-Hee; Kim, Heung-Up; Lee, Jaechun; Lee, Sang Pyo; Chung, Young-Bae

    2014-01-01

    Several studies have reported that the citrus red mites Panonychus citri were an important allergen of citrus-cultivating farmers in Jeju Island. The aim of the present study was to purify and assess properties of a cysteine protease from the mites acting as a potentially pathogenic factor to citrus-cultivating farmers. A cysteine protease was purified using column chromatography of Mono Q anion exchanger and Superdex 200 HR gel filtration. It was estimated to be 46 kDa by gel filtration colu...

  15. The biology and fecundity of the citrus red mite Panonychus citri (McGregor) (Acari: Tetranychidae) at different temperatures under laboratory conditions

    OpenAIRE

    KASAP, İsmail

    2009-01-01

    The developmental time and fecundity of Panonychus citri (McGregor 1916) (Acari: Tetranychidae) on Washington navel sweet orange (Citrus sinensis (L.) Osb.) leaves were determined at 15, 20, 25, 30 and 35 ± 1 °C, 65 ± 10% RH, and a 16:8-h (L:D) photoperiod under laboratory conditions. Total development time of P. citri females was 37.2, 16.6, 12.2, 9.8, and 9.0 days at 15, 20, 25, 30, and 35 ± 1 °C, respectively. Total and daily egg production levels of P. citri were highest at 25 °C (25.6 an...

  16. Using mass spectrometry for identification of ABC transporters from Xanthomonas citri and mutants expressed in different growth conditions

    Energy Technology Data Exchange (ETDEWEB)

    Faria, J.N.; Balan, A. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil); Paes Leme, A.F. [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil)

    2012-07-01

    Full text: Xanthomonas citri is a phytopathogenic bacterium that infects citrus plants causing significant losses for the economy. In our group, we have focused on the identification and characterization of ABC transport proteins of this bacterium, in order to determinate their function for growth in vitro and in vivo, during infection. ABC transporters represent one of the largest families of proteins, which transport since small molecules as ions up to oligopeptides and sugars. In prokaryotic cells many works have reported the ABC transport function in pathogenesis, resistance, biofilm formation, infectivity and DNA repair, but until our knowledge, there is no data related to these transporters and X. citri. So, In order to determinate which transporters are expressed in X. citri, we started a proteomic analysis based on mono and bi-dimensional gels associated to mass spectrometry analyses. After growing X. citri and two different mutants deleted for ssuA and nitA genes in LB and minimum media, cellular extracts were obtained and used for preparation of mono and bi-dimensional gels. Seven bands covering the expected mass of ABC transporter components (20 kDa to 50 kDa) in SDS-PAGE were cut off the gel, treated with trypsin and submitted to the MS for protein identification. The results of 2D gels were good enough and will serve as a standard for development of similar experiments in large scale. (author)

  17. Species limits in Diaporthe: molecular re-assessment of D. citri, D. cytosporella, D. foeniculina and D. rudis

    NARCIS (Netherlands)

    Udayanga, D.; Castlebury, L.A.; Rossman, A.Y.; Hyde, K.D.

    2014-01-01

    Species of Diaporthe are important plant pathogens of a wide range of hosts worldwide. In the present study the species causing melanose and stem end rot diseases of Citrus spp. are revised. Three species of Diaporthe occurring on Citrus are characterised, including D. citri, D. cytosporella and D.

  18. Toxicity of insecticidal soaps to the Asian citrus psyllid (Diaphorina citri) and two of its natural enemies

    Science.gov (United States)

    Insecticidal soaps (hereafter “soaps”) are labeled for use by homeowners and also can be used in citrus grown for the organic market. Soaps control some insect pests and therefore might be an alternative to conventional pesticides for control of the Asian citrus psyllid, Diaphorina citri Kuwayama (...

  19. Identification of differentially expressed genes of Xanthomonas axonopodis pv. citri by representational difference analysis of cDNA

    Directory of Open Access Journals (Sweden)

    Angela Mehta

    2005-03-01

    Full Text Available Xanthomonas axonopodis pv. citri is a phytopathogenic bacterium responsible for citrus canker, a serious disease which causes severe losses in citriculture around the world. In this study we report the differential expression of X. axonopodis pv. citri in response to specific treatments by using Representational Difference Analysis of cDNA (cDNA RDA. cDNAs from X. axonopodis pv. citri cultured in the presence of leaf extract of the host plant (Citrus sinensis, in vivo, as well as in the complex medium were hybridized against cDNA of the bacterium grown in the minimal medium. Sequencing of the difference products obtained after the second and third hybridizations revealed a total of 37 distinct genes identified by homology searches in the genome of X. axonopodis pv. citri. These genes were distributed in different functional categories, including genes that encode hypothetical proteins, genes involved in metabolism, cellular processes and pathogenicity, and mobile genetic elements. Most of these genes are likely related to growth and/or acquisition of nutrients in specific treatments whereas others might be important for the bacterium pathogenicity.

  20. Identification and Characterization of Seven Glutathione S-Transferase Genes from Citrus Red Mite, Panonychus citri (McGregor

    Directory of Open Access Journals (Sweden)

    Chong-Yu Liao

    2013-12-01

    Full Text Available The citrus red mite, Panonychus citri (McGregor, is a global citrus pest, and has developed severe resistance to several types of acaricides. However, the molecular mechanisms of resistance in this mite remain unknown. In this study, seven full-length cDNAs encoding glutathione S-transferases (GSTs genes were identified and characterized in P. citri. The effects of pyridaben and fenpropathrin exposure on the expression of these genes were also investigated. Phylogenetic analysis revealed that the seven GSTs genes in P. citri cloned in this study belong to three different cytosolic classes, including four in mu, two in delta and one in zeta. Among these seven GSTs genes, the relative expression level of PcGSTm1 was significantly higher in adult than in the other life stages (egg, larvae and nymph. Compared with the control, the mRNA levels of the seven GST genes did not change significantly following exposure to pyridaben at LC10. However, RT-qPCR results showed that, when exposed to LC10 of fenpropathrin, six GSTs gene (PcGSTm1, PcGSTm3, PcGSTm4, PcGSTd1, PcGSTd2 and PcGSTz1 transcripts increased in a time-dependent manner. This is the first insight into the molecular characteristics of GSTs gene cDNAs in P. citri. The elevated GSTs gene transcripts following exposure to fenpropathrin might be one of the mechanisms involved in detoxification of this acaricide.

  1. Identification and characterization of seven glutathione S-transferase genes from citrus red mite, Panonychus citri (McGregor).

    Science.gov (United States)

    Liao, Chong-Yu; Zhang, Kun; Niu, Jin-Zhi; Ding, Tian-Bo; Zhong, Rui; Xia, Wen-Kai; Dou, Wei; Wang, Jin-Jun

    2013-01-01

    The citrus red mite, Panonychus citri (McGregor), is a global citrus pest, and has developed severe resistance to several types of acaricides. However, the molecular mechanisms of resistance in this mite remain unknown. In this study, seven full-length cDNAs encoding glutathione S-transferases (GSTs) genes were identified and characterized in P. citri. The effects of pyridaben and fenpropathrin exposure on the expression of these genes were also investigated. Phylogenetic analysis revealed that the seven GSTs genes in P. citri cloned in this study belong to three different cytosolic classes, including four in mu, two in delta and one in zeta. Among these seven GSTs genes, the relative expression level of PcGSTm1 was significantly higher in adult than in the other life stages (egg, larvae and nymph). Compared with the control, the mRNA levels of the seven GST genes did not change significantly following exposure to pyridaben at LC10. However, RT-qPCR results showed that, when exposed to LC10 of fenpropathrin, six GSTs gene (PcGSTm1, PcGSTm3, PcGSTm4, PcGSTd1, PcGSTd2 and PcGSTz1) transcripts increased in a time-dependent manner. This is the first insight into the molecular characteristics of GSTs gene cDNAs in P. citri. The elevated GSTs gene transcripts following exposure to fenpropathrin might be one of the mechanisms involved in detoxification of this acaricide. PMID:24351815

  2. Produção e sensibilidade de isolados brasileiros de Xanthomonas axonopodis pv. citri à bacteriocinas

    Directory of Open Access Journals (Sweden)

    Marcel Bonini

    2012-09-01

    Full Text Available Este trabalho teve por objetivo avaliar a produção e a sensibilidade de 48 isolados brasileiros de X. axonopodis pv. citri (Xac à bacteriocinas. Pelos resultados obtidos, nenhum isolado de Xac foi sensível às bacteriocinas produzidas pelos isolados bacterianos avaliados.

  3. Influence of Host Plant Species and Flush Growth Stage on the Asian Citrus Psyllid, Diaphorina citri Kuwayama

    Directory of Open Access Journals (Sweden)

    Stephen L.C. Teck

    2011-01-01

    Full Text Available Problem statement: In order to establish the important host range of D. citri, the performance of this psyllid on different rutacous host plants was assessed. Apparent regional differences in host preferences of D. citri as noted above and the need for empirical knowledge of its host preferences in Malaysia where it is lacking. Approach: Experiments on host plant preference between citrus, jasmine orange and curry leaf were conducted over a period of 14 days in the field cage in October 1998 at the agricultural research centre, Semonggok, 15 km from Kuching, Kuching Division, Sarawak in Malaysia. Results: A comparative life cycle study of the Asian Citrus Psyllid Diaphorina citri Kuwayama on three different Rutaceous plant hosts namely citrus, jasmine orange and curry leaf plants was conducted inside the temperature controlled growth chamber maintain at 26 ± 1°C temperature, 75-80% relative humidity with artificial illumination intensity of 10,000 lux equipped with a photoperiod of 14:10 h light: dark regime to permit normal growth. Conclusion: The screenhouse studies confirmed that D. citri can colonise and breed on citrus, jasmine orange and curry leaf plant and that jasmine orange is the preferred host. It is also confirmed that females prefer to oviposit on immature flush 3-10 mm in length. In growth chamber experiments the life cycle of the psyllid was 18.5 days on jasmine orange, 19.0 days on citrus and 23.0 days on curry leaf.

  4. Development and reproduction of Panonychus citri (Prostigmata: Tetranychidae) on different species and varieties of citrus plants.

    Science.gov (United States)

    Zanardi, Odimar Zanuzo; Bordini, Gabriela Pavan; Franco, Aline Aparecida; de Morais, Matheus Rovere; Yamamoto, Pedro Takao

    2015-12-01

    The species and varieties of citrus plants that are currently grown can favor the population growth of the citrus red mite Panonychus citri (McGregor) (Prostigmata: Tetranychidae) and alter the pest management programs in citrus groves. In this study we evaluated, in the laboratory, the development and reproduction of P. citri and estimated its life table parameters when reared on four varieties of Citrus sinensis (L.) Osbeck (Valencia, Pera, Natal, and Hamlin), one variety of Citrus reticulata Blanco (Ponkan) and one variety of Citrus limon (L.) Burm. (Sicilian). The incubation period and egg viability were not affected by the host plant. However, the development and survival of the immature stage were significantly lower on Hamlin orange than on Valencia, Pera and Natal oranges, Ponkan mandarin and Sicilian lemon. The fecundity and oviposition period of females were lower on Hamlin orange than on the other hosts. Mites reared on Valencia orange and Sicilian lemon had a higher net reproductive rate (R 0 ), intrinsic growth rate (r) and finite rate of increase (λ), and a shorter interval between generations (T) than on Pera, Natal and Hamlin oranges and Ponkan mandarin. On the other hand, mites reared on Hamlin orange had the lowest R 0 , r and λ and the highest T among the hosts. Based on the results obtained we recommend that for Valencia orange and Sicilian lemon, the mite monitoring programs should be more intense to detect the initial infestation of pest, avoiding the damage in plants and the increase in production costs. PMID:26459376

  5. Characterization of the sulfate uptake and assimilation pathway from Xanthomonas citri - targets for bacterial growth inhibitors

    International Nuclear Information System (INIS)

    Full text: Microorganisms require sulfur for growth and obtain it either for inorganic sulfate or organosulfur compounds. ATP-Binding Cassete (SulT family) or major facilitator superfamily-type (SulP) transporters are responsible for the sulfate transport into the cell. In Xanthomonas citri, the phytopathogenic bacterium that causes the canker citrus disease, there are no reports related to the importance of these transporters during in vitro or in vivo infection. We identified in X. citri genome all the genes that belong to the well-characterized cys regulon from Escherichia coli and Salmonella typhimurium, which includes three ABC transporters and all the enzymes necessary for sulfate oxide reduction to sulfide and cysteine. Once these genes have been shown to be extremely important for bacteria growth and development in different environments, we chose the sbpcysWUA and cysDNCHIJG operons, which encodes the ABC inorganic sulfate ABC transporter and all the enzymes necessary for conversion of sulfate in cysteine, respectively. As a step for crystallization trials and resolution of their tridimensional structures, the referred genes were amplified and cloned into the cloning vector pGEM T-easy. In addition, using bioinformatics tools and molecular modeling we characterized all the protein functions as well as built tridimensional models of their structure for determination of the active sites. The importance of each protein is discussed aiming the discovery of a good target for development of inhibitors that could block the bacterium growth. (author)

  6. Insecticide sprays, natural enemy assemblages and predation on Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Monzo, C; Qureshi, J A; Stansly, P A

    2014-10-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of 'huanglongbing' (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB has driven implementation of intensive insecticide programs against ACP with unknown side effects on beneficial arthropod fauna in citrus agroecosystems. We evaluated effects of calendar sprays directed against this pest on natural enemy assemblages and used exclusion to estimate mortality they imposed on ACP populations in citrus groves. Predator exclusion techniques were used on nascent colonies of D. citri in replicated large untreated and sprayed plots of citrus during the four major flushing periods over 2 years. Population of spiders, arboreal ants and ladybeetles were independently assessed. Monthly sprays of recommended insecticides for control of ACP, adversely affected natural enemy populations resulting in reduced predation on ACP immature stages, especially during the critical late winter/early spring flush. Consequently, projected growth rates of the ACP population were greatest where natural enemies had been adversely affected by insecticides. Whereas, this result does not obviate the need for insecticidal control of ACP, it does indicate that even a selective regimen of sprays can impose as yet undetermined costs in terms of reduced biological control of this and probably other citrus pests.

  7. Insecticide sprays, natural enemy assemblages and predation on Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Monzo, C; Qureshi, J A; Stansly, P A

    2014-10-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of 'huanglongbing' (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB has driven implementation of intensive insecticide programs against ACP with unknown side effects on beneficial arthropod fauna in citrus agroecosystems. We evaluated effects of calendar sprays directed against this pest on natural enemy assemblages and used exclusion to estimate mortality they imposed on ACP populations in citrus groves. Predator exclusion techniques were used on nascent colonies of D. citri in replicated large untreated and sprayed plots of citrus during the four major flushing periods over 2 years. Population of spiders, arboreal ants and ladybeetles were independently assessed. Monthly sprays of recommended insecticides for control of ACP, adversely affected natural enemy populations resulting in reduced predation on ACP immature stages, especially during the critical late winter/early spring flush. Consequently, projected growth rates of the ACP population were greatest where natural enemies had been adversely affected by insecticides. Whereas, this result does not obviate the need for insecticidal control of ACP, it does indicate that even a selective regimen of sprays can impose as yet undetermined costs in terms of reduced biological control of this and probably other citrus pests. PMID:24830653

  8. Population dynamics and growth rates of endosymbionts during Diaphorina citri (Hemiptera, Liviidae) ontogeny.

    Science.gov (United States)

    Dossi, Fabio Cleisto Alda; da Silva, Edney Pereira; Cônsoli, Fernando Luis

    2014-11-01

    The infection density of symbionts is among the major parameters to understand their biological effects in host-endosymbionts interactions. Diaphorina citri harbors two bacteriome-associated bacterial endosymbionts (Candidatus Carsonella ruddii and Candidatus Profftella armatura), besides the intracellular reproductive parasite Wolbachia. In this study, the density dynamics of the three endosymbionts associated with the psyllid D. citri was investigated by real-time quantitative PCR (qPCR) at different developmental stages. Bacterial density was estimated by assessing the copy number of the 16S rRNA gene for Carsonella and Profftella, and of the ftsZ gene for Wolbachia. Analysis revealed a continuous growth of the symbionts during host development. Symbiont growth and rate curves were estimated by the Gompertz equation, which indicated a negative correlation between the degree of symbiont-host specialization and the time to achieve the maximum growth rate (t*). Carsonella densities were significantly lower than those of Profftella at all host developmental stages analyzed, even though they both displayed a similar trend. The growth rates of Wolbachia were similar to those of Carsonella, but Wolbachia was not as abundant. Adult males displayed higher symbiont densities than females. However, females showed a much more pronounced increase in symbiont density as they aged if compared to males, regardless of the incorporation of symbionts into female oocytes and egg laying. The increased density of endosymbionts in aged adults differs from the usual decrease observed during host aging in other insect-symbiont systems. PMID:25037159

  9. Development and reproduction of Panonychus citri (Prostigmata: Tetranychidae) on different species and varieties of citrus plants.

    Science.gov (United States)

    Zanardi, Odimar Zanuzo; Bordini, Gabriela Pavan; Franco, Aline Aparecida; de Morais, Matheus Rovere; Yamamoto, Pedro Takao

    2015-12-01

    The species and varieties of citrus plants that are currently grown can favor the population growth of the citrus red mite Panonychus citri (McGregor) (Prostigmata: Tetranychidae) and alter the pest management programs in citrus groves. In this study we evaluated, in the laboratory, the development and reproduction of P. citri and estimated its life table parameters when reared on four varieties of Citrus sinensis (L.) Osbeck (Valencia, Pera, Natal, and Hamlin), one variety of Citrus reticulata Blanco (Ponkan) and one variety of Citrus limon (L.) Burm. (Sicilian). The incubation period and egg viability were not affected by the host plant. However, the development and survival of the immature stage were significantly lower on Hamlin orange than on Valencia, Pera and Natal oranges, Ponkan mandarin and Sicilian lemon. The fecundity and oviposition period of females were lower on Hamlin orange than on the other hosts. Mites reared on Valencia orange and Sicilian lemon had a higher net reproductive rate (R 0 ), intrinsic growth rate (r) and finite rate of increase (λ), and a shorter interval between generations (T) than on Pera, Natal and Hamlin oranges and Ponkan mandarin. On the other hand, mites reared on Hamlin orange had the lowest R 0 , r and λ and the highest T among the hosts. Based on the results obtained we recommend that for Valencia orange and Sicilian lemon, the mite monitoring programs should be more intense to detect the initial infestation of pest, avoiding the damage in plants and the increase in production costs.

  10. Population dynamics and growth rates of endosymbionts during Diaphorina citri (Hemiptera, Liviidae) ontogeny.

    Science.gov (United States)

    Dossi, Fabio Cleisto Alda; da Silva, Edney Pereira; Cônsoli, Fernando Luis

    2014-11-01

    The infection density of symbionts is among the major parameters to understand their biological effects in host-endosymbionts interactions. Diaphorina citri harbors two bacteriome-associated bacterial endosymbionts (Candidatus Carsonella ruddii and Candidatus Profftella armatura), besides the intracellular reproductive parasite Wolbachia. In this study, the density dynamics of the three endosymbionts associated with the psyllid D. citri was investigated by real-time quantitative PCR (qPCR) at different developmental stages. Bacterial density was estimated by assessing the copy number of the 16S rRNA gene for Carsonella and Profftella, and of the ftsZ gene for Wolbachia. Analysis revealed a continuous growth of the symbionts during host development. Symbiont growth and rate curves were estimated by the Gompertz equation, which indicated a negative correlation between the degree of symbiont-host specialization and the time to achieve the maximum growth rate (t*). Carsonella densities were significantly lower than those of Profftella at all host developmental stages analyzed, even though they both displayed a similar trend. The growth rates of Wolbachia were similar to those of Carsonella, but Wolbachia was not as abundant. Adult males displayed higher symbiont densities than females. However, females showed a much more pronounced increase in symbiont density as they aged if compared to males, regardless of the incorporation of symbionts into female oocytes and egg laying. The increased density of endosymbionts in aged adults differs from the usual decrease observed during host aging in other insect-symbiont systems.

  11. Characterization of the sulfate uptake and assimilation pathway from Xanthomonas citri - targets for bacterial growth inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Tambascia, C.; Balan, A. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil)

    2012-07-01

    Full text: Microorganisms require sulfur for growth and obtain it either for inorganic sulfate or organosulfur compounds. ATP-Binding Cassete (SulT family) or major facilitator superfamily-type (SulP) transporters are responsible for the sulfate transport into the cell. In Xanthomonas citri, the phytopathogenic bacterium that causes the canker citrus disease, there are no reports related to the importance of these transporters during in vitro or in vivo infection. We identified in X. citri genome all the genes that belong to the well-characterized cys regulon from Escherichia coli and Salmonella typhimurium, which includes three ABC transporters and all the enzymes necessary for sulfate oxide reduction to sulfide and cysteine. Once these genes have been shown to be extremely important for bacteria growth and development in different environments, we chose the sbpcysWUA and cysDNCHIJG operons, which encodes the ABC inorganic sulfate ABC transporter and all the enzymes necessary for conversion of sulfate in cysteine, respectively. As a step for crystallization trials and resolution of their tridimensional structures, the referred genes were amplified and cloned into the cloning vector pGEM T-easy. In addition, using bioinformatics tools and molecular modeling we characterized all the protein functions as well as built tridimensional models of their structure for determination of the active sites. The importance of each protein is discussed aiming the discovery of a good target for development of inhibitors that could block the bacterium growth. (author)

  12. Acaricidal activity against Panonychus citri and active ingredient of the mangrove plant Cerbera manghas.

    Science.gov (United States)

    Deng, Yecheng; Yongmei Liao; Li, Jingjing; Yang, Linlin; Zhong, Hui; Zhou, Qiuyan; Qing, Zhen

    2014-09-01

    Cerbera manghas is a mangrove plant which possesses comprehensive biological activities. A great deal of research has been undertaken on the chemical constituents and medical functions of C. manghas; insecticidal and antifungal activities have also been reported, but the acaricidal activity has not been studied. In our study, the acaricidal activity and active substances of C. manghas were investigated using a spray method, which showed that the methanol extracts of the fruit, twigs and leaves exhibited contact activity against female adults of Panonychus citri, with LC50 values at 24 h of 3.39 g L(-1), 4.09 g L(-1) and 4.11 g L(-1), respectively. An acaricidal compound was isolated from C. manghas by an activity-guided isolation method, and identified as (-)-17β-neriifolin, which is a cardiac glycoside. (-)-17β-Neriifolin revealed high contact activity against female adults, nymphae, larvae and eggs of P. citri, with LC50 values at 24 h of 0.28 g L(-1), 0.29 g L(-1), 0.28 g L(-1) and 1.45 g L(-1), respectively. PMID:25918788

  13. Molecular characterization of two carboxylesterase genes of the citrus red mite, Panonychus citri (Acari: Tetranychidae).

    Science.gov (United States)

    Zhang, Kun; Niu, Jin-Zhi; Ding, Tian-Bo; Dou, Wei; Wang, Jin-Jun

    2013-04-01

    The citrus red mite, Panonychus citri, is known for its ability to rapidly evolve resistance to insecticides/acaricides and to adapt to hosts that produce toxins. To get better insight into the detoxification mechanism of P. citri, two carboxylesterase (CarE) genes, PCE1 and PCE2, were isolated and characterized. PCE1 and PCE2 contained open reading frames of 1,653 and 1,392 nucleotides, encoding proteins of 550 and 463 amino acid residues, respectively. Phylogenetic analyses showed that PCE1 and PCE2 were most closely related to the CarE genes from other phytophagous mites. The transcriptional profiles of two CarE genes among developmental stages (egg, larva, nymph, adult female, and adult male), after exposing to four acaricides (avermectin, azocyclotin, pyridaben, and spirodiclofen) and acid rain were investigated using real-time quantitative PCR (qPCR). The results showed that during development, PCE1 was highly expressed at the egg stage, whereas PCE2 was abundantly expressed at the adult stage of males. The expression levels of PCE1 were highly induced upon exposure to acaricides and acid rain. On the other hand, the expression levels of PCE2 were increased after treatment with avermectin and pyridaben. These results suggest that PCE1 and PCE2 may have distinct roles in different developmental stages and participate in the detoxification of acaricides. PMID:23404785

  14. A novel two-component response regulator links rpf with biofilm formation and virulence of Xanthomonas axonopodis pv. citri.

    Directory of Open Access Journals (Sweden)

    Tzu-Pi Huang

    Full Text Available Citrus bacterial canker caused by Xanthomonas axonopodis pv. citri is a serious disease that impacts citrus production worldwide, and X. axonopodis pv. citri is listed as a quarantine pest in certain countries. Biofilm formation is important for the successful development of a pathogenic relationship between various bacteria and their host(s. To understand the mechanisms of biofilm formation by X. axonopodis pv. citri strain XW19, the strain was subjected to transposon mutagenesis. One mutant with a mutation in a two-component response regulator gene that was deficient in biofilm formation on a polystyrene microplate was selected for further study. The protein was designated as BfdR for biofilm formation defective regulator. BfdR from strain XW19 shares 100% amino acid sequence identity with XAC1284 of X. axonopodis pv. citri strain 306 and 30-100% identity with two-component response regulators in various pathogens and environmental microorganisms. The bfdR mutant strain exhibited significantly decreased biofilm formation on the leaf surfaces of Mexican lime compared with the wild type strain. The bfdR mutant was also compromised in its ability to cause canker lesions. The wild-type phenotype was restored by providing pbfdR in trans in the bfdR mutant. Our data indicated that BfdR did not regulate the production of virulence-related extracellular enzymes including amylase, lipase, protease, and lecithinase or the expression of hrpG, rfbC, and katE; however, BfdR controlled the expression of rpfF in XVM2 medium, which mimics cytoplasmic fluids in planta. In conclusion, biofilm formation on leaf surfaces of citrus is important for canker development in X. axonopodis pv. citri XW19. The process is controlled by the two-component response regulator BfdR via regulation of rpfF, which is required for the biosynthesis of a diffusible signal factor.

  15. Evaluation of six different groups of insecticides for the control of citrus psylla Diaphorina citri (Hemiptera: Psyllidae

    Directory of Open Access Journals (Sweden)

    Rakhmin Gul

    2005-01-01

    Full Text Available Studies on the efficacy of different insecticides against citrus psylla, Diaphorina citri (Hemiptera: Psyllidae were carried out at Agricultural Research Institute, Tarnab, Peshawar, Pakistan. Six insecticides viz. Actara 25 WG, (thiamethoxam Cascade 10 DC (Flufenoxuron, Match 050 EC (lufenuron, Thiodan 35 EC (endosulfan, Karate 2.5 EC (α-cyhalothrin, and Supracide 40 EC (methidathion, were tested for their effectiveness against D. citri. After first spray overall mean population of D. citri was 3.63, 4.75, 5.59, 6.66, 7.47, 8.11 per six inches tender shoot on Actara 25 WG, Cascade 10 DC, Match 050 EC, Thiodan 35 EC, Karate 2.5 EC and Supracide 40 EC treated plants respectively, while on control plants the population was 12.39. Similarly, after the second spray of each of the same insecticides the population of D. citri was 2.65, 4.23, 5.61, 6.41, 7.35 and 8.73 respectively. Where in controls there were 15.18 psyllids. Percent decrease of D. citri population in comparison to control after the first spray was highest in Actara 25 WG (72.20 followed by Cascade 10 DC (62.91, Match 050 EC (54.07, Thiodan 35 EC (47.61, Karate 2.5 EC (38.94 and Supracide 40 EC (35.74. After the second spray percent decrease over control recorded was highest in Actara 25 WG (83.54, followed by Cascade 10 DC (71.08, Match 050 EC (63.94, Thiodan 35 EC (60.79, Karate 2.5 EC (52.52 and Supracide 40 EC (45.62.

  16. A LOV protein modulates the physiological attributes of Xanthomonas axonopodis pv. citri relevant for host plant colonization.

    Directory of Open Access Journals (Sweden)

    Ivana Kraiselburd

    Full Text Available Recent studies have demonstrated that an appropriate light environment is required for the establishment of efficient vegetal resistance responses in several plant-pathogen interactions. The photoreceptors implicated in such responses are mainly those belonging to the phytochrome family. Data obtained from bacterial genome sequences revealed the presence of photosensory proteins of the BLUF (Blue Light sensing Using FAD, LOV (Light, Oxygen, Voltage and phytochrome families with no known functions. Xanthomonas axonopodis pv. citri is a Gram-negative bacterium responsible for citrus canker. The in silico analysis of the X. axonopodis pv. citri genome sequence revealed the presence of a gene encoding a putative LOV photoreceptor, in addition to two genes encoding BLUF proteins. This suggests that blue light sensing could play a role in X. axonopodis pv. citri physiology. We obtained the recombinant Xac-LOV protein by expression in Escherichia coli and performed a spectroscopic analysis of the purified protein, which demonstrated that it has a canonical LOV photochemistry. We also constructed a mutant strain of X. axonopodis pv. citri lacking the LOV protein and found that the loss of this protein altered bacterial motility, exopolysaccharide production and biofilm formation. Moreover, we observed that the adhesion of the mutant strain to abiotic and biotic surfaces was significantly diminished compared to the wild-type. Finally, inoculation of orange (Citrus sinensis leaves with the mutant strain of X. axonopodis pv. citri resulted in marked differences in the development of symptoms in plant tissues relative to the wild-type, suggesting a role for the Xac-LOV protein in the pathogenic process. Altogether, these results suggest the novel involvement of a photosensory system in the regulation of physiological attributes of a phytopathogenic bacterium. A functional blue light receptor in Xanthomonas spp. has been described for the first time, showing

  17. Volatile allelochemicals in the Ageratum conyzoides intercropped citrus orchard and their effects on mites Amblyseius newsami and Panonychus citri.

    Science.gov (United States)

    Kong, Chuihua; Hu, Fei; Xu, Xiaohua; Zhang, Maoxin; Liang, Wenju

    2005-09-01

    Ageratum conyzoides L. weed often invades cultivated fields and reduces crop productivity in Southeast Asia and South China. However, intercropping this weed in citrus orchards may increase the population of predatory mite Amblyseius newsami, an effective natural enemy of citrus red mite Panonychus citri, and keep the population of P. citri at low and noninjurious levels. This study showed that A. conyzoides produced and released volatile allelochemicals into the air in the intercropped citrus orchard, and these volatiles influenced the olfactory responses of A. newsami and P. citri. At test temperature (25 degrees C), A. conyzoides fresh leaves, its essential oil, and major constituents, demethoxy-ageratochromene, beta-caryophyllene, alpha-bisabolene, and E-beta-farnesene, attracted A. newsami and slightly repelled P. citri. Field experiments demonstrated that spraying A. conyzoides essential oil emulsion in an A. conyzoides nonintercropped citrus orchard increased the population density of A. newsami from below 0.1 to over 0.3 individuals per leaf, reaching the same level as in an A. conyzoides intercropped citrus orchard. However, this effect could not be maintained beyond 48 hr because of the volatility of the essential oil. In contrast, in the A. conyzoides intercropped citrus orchard, A. conyzoides plants continuously produced and released volatile allelochemicals and maintained the A. newsami population for a long time. The results suggest that intercropping of A. conyzoides not only made the citrus orchard ecosystem more favorable for the predatory mite A. newsami, but also that the volatile allelochemicals released from A. conyzoides regulated the population of A. newsami and P. citri. PMID:16132220

  18. Genetic diversity and population structure of Panonychus citri (Acari: Tetranychidae), in China based on mitochondrial COI gene sequences.

    Science.gov (United States)

    Yuan, Ming-Long; Wei, Dan-Dan; Zhang, Kun; Gao, Yu-Zhen; Liu, Yong-Hua; Wang, Bao-Jun; Wang, Jin-Jun

    2010-12-01

    The citrus red mite, Panonychus citri (McGregor) (Acari: Tetranychidae), is regarded as one of the most important citrus pests in many countries, such as Japan, Spain, and China. In this study, the mitochondrial cytochrome oxidase subunit I gene was used to analyze genetic diversity and population structure of 15 P. citri populations collected from three citrus (Citrus spp.) planting regions of China. Our analysis found that these populations had relatively low genetic diversities. Bayesian tree and haplotype network showed that the 22 haplotypes of P. citri formed two lineages with low Bayesian posterior probabilities (0.55 and 0.63), and haplotypes in a sample were scattered throughout the Bayesian tree, indicating that there may be no significant genealogical structure among populations. However, when Yuxi and Danjiangkou populations (both without H7 haplotype) were excluded from the analysis, analysis of molecular variance found a weak, but significant, geographic structuring. Mantel test indicated a significant and positive correlation between genetic and geographical distances, reflecting certain degree of isolation by distance. The genetic differentiation based on pairwise F(ST) was not significant between most populations, and some F(ST) were even negative, indicating remarkable gene flow among these populations. The weak population structure of P. citri in this study was probably influenced by high gene flow between some populations due to long-distance dispersal of this species, which may be largely relied on the movement of plants between populations. The mismatch distribution analysis showed that no signal of population growth, but the Fu's F(S) value was significantly negative for total populations and the star-like shape of haplotype network, suggesting a history of population expansion of P. citri in China. PMID:21309245

  19. Host Range Testing of Diaphorencyrtus aligarhensis (Hymenoptera: Encyrtidae) for Use in Classical Biological Control of Diaphorina citri (Hemiptera: Liviidae) in California.

    Science.gov (United States)

    Bistline-East, Allison; Pandey, Raju; Kececi, Mehmet; Hoddle, Mark S

    2015-06-01

    Host range tests for Diaphorencyrtus aligarhensis (Shafee, Alam, & Agarwal) (Hymenoptera: Encyrtidae), an endoparasitoid of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), sourced from Punjab Pakistan, were conducted in quarantine at the University of California, Riverside, CA. Seven nontarget psyllid species representing four psyllid families were exposed to mated D. aligarhensis females in four different treatment types: 1) short sequential no-choice treatments, 2) prolonged sequential no-choice treatments, 3) prolonged no-choice static treatments, and 4) choice treatments. Selection of nontarget psyllid species was based on phylogenetic proximity to D. citri, likelihood of being encountered by D. aligarhensis in the prospective release areas in California, and psyllid species in biological control of invasive weeds. D. aligarhensis exhibited high host affinity to D. citri, and only parasitized one nontarget species, the pestiferous potato psyllid, Bactericera cockerelli (Sulc), at low levels (citri. Results presented here suggest D. aligarhensis poses minimal risk to nontarget psyllid species in California. PMID:26470214

  20. Signalering van citruswolluis (Planococcus citri) in de teelt van diverse potplanten : onderzoek binnen project 41203147 "Verbetering biologische bestrijding van wolluis in diverse potplanten”

    NARCIS (Netherlands)

    Boertjes, B.C.; Bruin, de J.

    2003-01-01

    In 2002 en 2003 is door PPO Glastuinbouw het project “Verbetering biologische bestrijding van wolluis in diverse potplanten” (project 41203147) uitgevoerd. Binnen dit project werd onder meer onderzoek gedaan naar methoden om citruswolluis (Planococcus citri) te signaleren.

  1. Host Range Testing of Diaphorencyrtus aligarhensis (Hymenoptera: Encyrtidae) for Use in Classical Biological Control of Diaphorina citri (Hemiptera: Liviidae) in California.

    Science.gov (United States)

    Bistline-East, Allison; Pandey, Raju; Kececi, Mehmet; Hoddle, Mark S

    2015-06-01

    Host range tests for Diaphorencyrtus aligarhensis (Shafee, Alam, & Agarwal) (Hymenoptera: Encyrtidae), an endoparasitoid of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), sourced from Punjab Pakistan, were conducted in quarantine at the University of California, Riverside, CA. Seven nontarget psyllid species representing four psyllid families were exposed to mated D. aligarhensis females in four different treatment types: 1) short sequential no-choice treatments, 2) prolonged sequential no-choice treatments, 3) prolonged no-choice static treatments, and 4) choice treatments. Selection of nontarget psyllid species was based on phylogenetic proximity to D. citri, likelihood of being encountered by D. aligarhensis in the prospective release areas in California, and psyllid species in biological control of invasive weeds. D. aligarhensis exhibited high host affinity to D. citri, and only parasitized one nontarget species, the pestiferous potato psyllid, Bactericera cockerelli (Sulc), at low levels (citri. Results presented here suggest D. aligarhensis poses minimal risk to nontarget psyllid species in California.

  2. Biology of three species of Agistemus (Acari: Stigmaeidae): life table parameters using eggs of Panonychus citri or pollen of Malephora crocea as food.

    Science.gov (United States)

    Goldarazena, Arturo; Aguilar, Hugo; Kutuk, Halil; Childers, Carl C

    2004-01-01

    The biology and life table parameters of Agistemus industani Gonzalez, A. cyprius Gonzalez, and A. floridanus Gonzalez (Acari: Stigmaeidae) were studied under laboratory conditions using two food sources: Panonychus citri (McGregor) eggs or ice plant, Malephora crocea (Jacquin) Schwantes pollen at 25 degrees C. The larval, protonymph, deutonymph, and adult stages of A. industani fed on citrus red mite eggs. All active stages of A. industani, except the larva, fed on all P. citri stages and the larval stage could not feed on P. citri adults. All immature stages of A. industani fed on M. crocea pollen. Agistemus cyprius larvae fed on P. citri eggs and larvae or ice plant pollen. The nymphal stages fed on P. citri eggs, larvae, and protonymphs but not deutonymphs or adults while A. cyprius deutonymphs and adults fed on all P. citri stages. Adult and nymphal stages of A. cyprius fed on ice plant pollen and successfully completed their development while A. floridanus did not. Agistemus floridanus larvae fed only on P. citri eggs, while the other stages fed on P. citri eggs, larvae, and protonymphs. The developmental times from egg to adult for A. industani and A. cyprius when fed M. crocea pollen were 11.3 and 13.4 days, respectively. Agistemus floridanus was unable to complete its life cycle on a diet of only M. crocea pollen. Agistemus industani, A. cyprius, and A. floridanus completed development from egg to adult in 11.7, 13.8, and 10.8 days, respectively, when fed P. citri eggs. The intrinsic rate of increase (r(m)) values for A. cyprius and A. industani were 0.0311 and 0.1201 per day on the pollen diet. The net reproductive rate (Ro) was 3.58 for A. cyprius and 10.07 for A. industani with generation times (T) of 45.2 and 35.1 days, respectively, on the ice plant pollen diet. The r(m) values for A. cyprius, A. floridanus, and A. industani on the P. citri egg only diet were: 0.0562, 0.1001, and 0.1031 per day, respectively. The Ro values for each species fed P

  3. Double-stranded RNA uptake through topical application, mediates silencing of five CYP4 genes and suppresses insecticide resistance in Diaphorina citri.

    Science.gov (United States)

    Killiny, Nabil; Hajeri, Subhas; Tiwari, Siddharth; Gowda, Siddarame; Stelinski, Lukasz L

    2014-01-01

    Silencing of genes through RNA interference (RNAi) in insects has gained momentum during the past few years. RNAi has been used to cause insect mortality, inhibit insect growth, increase insecticide susceptibility, and prevent the development of insecticide resistance. We investigated the efficacy of topically applied dsRNA to induce RNAi for five Cytochrome P450 genes family 4 (CYP4) in Diaphorina citri. We previously reported that these CYP4 genes are associated with the development of insecticide resistance in D. citri. We targeted five CYP4 genes that share a consensus sequence with one dsRNA construct. Quantitative PCR confirmed suppressed expression of the five CYP4 genes as a result of dsRNA topically applied to the thoracic region of D. citri when compared to the expression levels in a control group. Western blot analysis indicated a reduced signal of cytochrome P450 proteins (45 kDa) in adult D. citri treated with the dsRNA. In addition, oxidase activity and insecticide resistance were reduced for D. citri treated with dsRNA that targeted specific CYP4 genes. Mortality was significantly higher in adults treated with dsRNA than in adults treated with water. Our results indicate that topically applied dsRNA can penetrate the cuticle of D. citri and induce RNAi. These results broaden the scope of RNAi as a mechanism to manage pests by targeting a broad range of genes. The results also support the application of RNAi as a viable tool to overcome insecticide resistance development in D. citri populations. However, further research is needed to develop grower-friendly delivery systems for the application of dsRNA under field conditions. Considering the high specificity of dsRNA, this tool can also be used for management of D. citri by targeting physiologically critical genes involved in growth and development. PMID:25330026

  4. Double-stranded RNA uptake through topical application, mediates silencing of five CYP4 genes and suppresses insecticide resistance in Diaphorina citri.

    Directory of Open Access Journals (Sweden)

    Nabil Killiny

    Full Text Available Silencing of genes through RNA interference (RNAi in insects has gained momentum during the past few years. RNAi has been used to cause insect mortality, inhibit insect growth, increase insecticide susceptibility, and prevent the development of insecticide resistance. We investigated the efficacy of topically applied dsRNA to induce RNAi for five Cytochrome P450 genes family 4 (CYP4 in Diaphorina citri. We previously reported that these CYP4 genes are associated with the development of insecticide resistance in D. citri. We targeted five CYP4 genes that share a consensus sequence with one dsRNA construct. Quantitative PCR confirmed suppressed expression of the five CYP4 genes as a result of dsRNA topically applied to the thoracic region of D. citri when compared to the expression levels in a control group. Western blot analysis indicated a reduced signal of cytochrome P450 proteins (45 kDa in adult D. citri treated with the dsRNA. In addition, oxidase activity and insecticide resistance were reduced for D. citri treated with dsRNA that targeted specific CYP4 genes. Mortality was significantly higher in adults treated with dsRNA than in adults treated with water. Our results indicate that topically applied dsRNA can penetrate the cuticle of D. citri and induce RNAi. These results broaden the scope of RNAi as a mechanism to manage pests by targeting a broad range of genes. The results also support the application of RNAi as a viable tool to overcome insecticide resistance development in D. citri populations. However, further research is needed to develop grower-friendly delivery systems for the application of dsRNA under field conditions. Considering the high specificity of dsRNA, this tool can also be used for management of D. citri by targeting physiologically critical genes involved in growth and development.

  5. Double-stranded RNA uptake through topical application, mediates silencing of five CYP4 genes and suppresses insecticide resistance in Diaphorina citri.

    Science.gov (United States)

    Killiny, Nabil; Hajeri, Subhas; Tiwari, Siddharth; Gowda, Siddarame; Stelinski, Lukasz L

    2014-01-01

    Silencing of genes through RNA interference (RNAi) in insects has gained momentum during the past few years. RNAi has been used to cause insect mortality, inhibit insect growth, increase insecticide susceptibility, and prevent the development of insecticide resistance. We investigated the efficacy of topically applied dsRNA to induce RNAi for five Cytochrome P450 genes family 4 (CYP4) in Diaphorina citri. We previously reported that these CYP4 genes are associated with the development of insecticide resistance in D. citri. We targeted five CYP4 genes that share a consensus sequence with one dsRNA construct. Quantitative PCR confirmed suppressed expression of the five CYP4 genes as a result of dsRNA topically applied to the thoracic region of D. citri when compared to the expression levels in a control group. Western blot analysis indicated a reduced signal of cytochrome P450 proteins (45 kDa) in adult D. citri treated with the dsRNA. In addition, oxidase activity and insecticide resistance were reduced for D. citri treated with dsRNA that targeted specific CYP4 genes. Mortality was significantly higher in adults treated with dsRNA than in adults treated with water. Our results indicate that topically applied dsRNA can penetrate the cuticle of D. citri and induce RNAi. These results broaden the scope of RNAi as a mechanism to manage pests by targeting a broad range of genes. The results also support the application of RNAi as a viable tool to overcome insecticide resistance development in D. citri populations. However, further research is needed to develop grower-friendly delivery systems for the application of dsRNA under field conditions. Considering the high specificity of dsRNA, this tool can also be used for management of D. citri by targeting physiologically critical genes involved in growth and development.

  6. Citrus tristeza virus-based RNAi in citrus plants induces gene silencing in Diaphorina citri, a phloem-sap sucking insect vector of citrus greening disease (Huanglongbing).

    Science.gov (United States)

    Hajeri, Subhas; Killiny, Nabil; El-Mohtar, Choaa; Dawson, William O; Gowda, Siddarame

    2014-04-20

    A transient expression vector based on Citrus tristeza virus (CTV) is unusually stable. Because of its stability it is being considered for use in the field to control Huanglongbing (HLB), which is caused by Candidatus Liberibacter asiaticus (CLas) and vectored by Asian citrus psyllid, Diaphorina citri. In the absence of effective control strategies for CLas, emphasis has been on control of D. citri. Coincident cohabitation in phloem tissue by CLas, D. citri and CTV was exploited to develop a novel method to mitigate HLB through RNA interference (RNAi). Since CTV has three RNA silencing suppressors, it was not known if CTV-based vector could induce RNAi in citrus. Yet, expression of sequences targeting citrus phytoene desaturase gene by CTV-RNAi resulted in photo-bleaching phenotype. CTV-RNAi vector, engineered with truncated abnormal wing disc (Awd) gene of D. citri, induced altered Awd expression when silencing triggers ingested by feeding D. citri nymphs. Decreased Awd in nymphs resulted in malformed-wing phenotype in adults and increased adult mortality. This impaired ability of D. citri to fly would potentially limit the successful vectoring of CLas bacteria between citrus trees in the grove. CTV-RNAi vector would be relevant for fast-track screening of candidate sequences for RNAi-mediated pest control.

  7. Citrus tristeza virus-based RNAi in citrus plants induces gene silencing in Diaphorina citri, a phloem-sap sucking insect vector of citrus greening disease (Huanglongbing).

    Science.gov (United States)

    Hajeri, Subhas; Killiny, Nabil; El-Mohtar, Choaa; Dawson, William O; Gowda, Siddarame

    2014-04-20

    A transient expression vector based on Citrus tristeza virus (CTV) is unusually stable. Because of its stability it is being considered for use in the field to control Huanglongbing (HLB), which is caused by Candidatus Liberibacter asiaticus (CLas) and vectored by Asian citrus psyllid, Diaphorina citri. In the absence of effective control strategies for CLas, emphasis has been on control of D. citri. Coincident cohabitation in phloem tissue by CLas, D. citri and CTV was exploited to develop a novel method to mitigate HLB through RNA interference (RNAi). Since CTV has three RNA silencing suppressors, it was not known if CTV-based vector could induce RNAi in citrus. Yet, expression of sequences targeting citrus phytoene desaturase gene by CTV-RNAi resulted in photo-bleaching phenotype. CTV-RNAi vector, engineered with truncated abnormal wing disc (Awd) gene of D. citri, induced altered Awd expression when silencing triggers ingested by feeding D. citri nymphs. Decreased Awd in nymphs resulted in malformed-wing phenotype in adults and increased adult mortality. This impaired ability of D. citri to fly would potentially limit the successful vectoring of CLas bacteria between citrus trees in the grove. CTV-RNAi vector would be relevant for fast-track screening of candidate sequences for RNAi-mediated pest control. PMID:24572372

  8. Better Together: Association With ‘Candidatus Liberibacter Asiaticus’ Increases the Reproductive Fitness of Its Insect Vector, Diaphorina citri (Hemiptera: Liviidae)

    Science.gov (United States)

    Pelz-Stelinski, K. S.; Killiny, N.

    2016-01-01

    The duration of the evolutionary association between a pathogen and vector can be inferred based on the strength of their mutualistic interactions. A well-adapted pathogen is likely to confer some benefit or, at a minimum, exhibit low pathogenicity toward its host vector. Coevolution of the two toward a mutually beneficial association appears to have occurred between the citrus greening disease pathogen, Candidatus Liberibacter asiaticus (Las), and its insect vector, the Asian citrus psyllid, Diaphorina citri (Kuwayama). To better understand the dynamics facilitating transmission, we evaluated the effects of Las infection on the fitness of its vector. Diaphorina citri harboring Las were more fecund than their uninfected counterparts; however, their nymphal development rate and adult survival were comparatively reduced. The finite rate of population increase and net reproductive rate were both greater among Las-infected D. citri as compared with uninfected counterparts, indicating that overall population fitness of infected psyllids was improved given the greater number of offspring produced. Previous reports of transovarial transmission, in conjunction with increased fecundity and population growth rates of Las-positive D. citri found in the current investigation, suggest a long evolutionary relationship between pathogen and vector. The survival of Las-infected adult D. citri was lower compared with uninfected D. citri, which suggests that there may be a fitness trade-off in response to Las infection. A beneficial effect of a plant pathogen on vector fitness may indicate that the pathogen developed a relationship with the insect before secondarily moving to plants. PMID:27418697

  9. Spatial distribution of Diaphorina citri Kuwayama (Hemiptera: Psyllidae in citrus orchards Distribuição espacial de Diaphorina citri Kuwayama (Hemiptera: Psyllidae em pomares de citros

    Directory of Open Access Journals (Sweden)

    Marilia Gregolin Costa

    2010-10-01

    Full Text Available The psyllid Diaphorina citri Kuwayama is one of the most important pests of citrus, mainly because it is the vector of the bacterium that causes huanglongbing (HLB or 'Greening' disease. To study the spatial distribution of nymphs and adults of this pest, an experiment was carried out in two 'Valencia' sweet orange orchards, four and 12 years of age, established in Matão, central area of São Paulo state, Brazil. The following dispersion indices were used to study pest aggregation in the citrus plants: variance/mean relationship (I, index of Morisita (Iδ, coefficient of Green (Cx, the exponent of negative binomial distribution, common k (c and Taylor's Power Law for each sampling. The negative binomial distribution was more representative of the spatial distribution of this psyllid, for both nymphs and adults. For most samplings, psyllid nymphs found in branches and adults caught in traps had an aggregated distribution.O psilídeo Diaphorina citri Kuwayama tornou-se nos últimos anos uma das mais importantes pragas na cultura de citros, principalmente pelos prejuízos causados às plantas por ser o transmissor da bactéria causadora da doença Huanglongbing (HLB ou 'Greening'. Com a finalidade de estudar a distribuição espacial de ninfas e adultos desta praga, instalaram-se experimentos em duas áreas de citros com histórico de ocorrência de HLB, no município de Matão (região central do Estado de São Paulo, em plantas de laranja 'Valência', com quatro e 12 anos de idade. Para estudo da agregação da população nas plantas, foram utilizados os seguintes índices de dispersão: razão variância/média (I, índice de Morisita (Iδ, coeficiente de Green (Cx e expoente da distribuição binomial negativa, k comum (c e lei da potência de Taylor para cada amostragem. A distribuição binomial negativa foi o modelo mais adequado para representar a distribuição espacial do psilídeo, tanto para ninfas como para adultos. Na maioria das

  10. Significance of habitat type for the genetic population structure of Panonychus citri (Acari: Tetranychidae).

    Science.gov (United States)

    Osakabe, Masahiro; Goka, Kouichi; Toda, Satoshi; Shintaku, Toshiyuki; Amano, Hiroshi

    2005-01-01

    Restricted migration and habitat fragmentation promote genetic differentiation between populations. Because most of the hosts of Panonychus citri are woody plants, mainly citrus trees that are usually planted at intervals of several metres, this mite likely faces more risks (e.g., starvation) by dispersing between host plants, compared to other spider mite species that infest both herbaceous and woody plants, such as Tetranychus urticae. Such a limited gene flow between patches (host plants) can lead to differentiation of populations even within a small area. Therefore, we hypothesize that P. citri populations are genetically differentiated not only between distant populations but also within small areas, such as within a grove. To test this hypothesis, we investigated the divergence of P. citri populations in Japanese citrus groves according to a hierarchical arrangement of geographical distance, ranging from distant populations (10 groves distributed throughout different areas in two major Japanese islands; this level of analysis is referred to as 'geographic') to local populations (different trees in a specific grove; 'local'). Three molecular markers were used: an esterase locus, one microsatellite and a point mutation in the mitochondrial cytochrome oxidase subunit I. At a local level acaricide susceptibility tests were also performed using two acaricides: fenpyroximate (25 ppm) and etoxazole (3.33 ppm). At a broad geographic level the gene diversity decreased with decreasing area size and distance between populations. By contrast, at the local level, populations maintained a significant level of variation between trees within groves, and the divergence within groves was higher than between groves. Whereas no statistical difference of the mortalities was detected among groves for the two acaricides tested, the difference was statistically significant among trees within groves in fenpyroximate (ANOVA, pcitri populations maintain a higher level of variation

  11. Chemical Composition, Antioxidant and Antimicrobial Activity of Pericarpium Citri Reticulatae Essential Oil

    Directory of Open Access Journals (Sweden)

    Bei Gao

    2011-05-01

    Full Text Available The chemical composition, antioxidant and antimicrobial activity of Pericarpium Citri Reticulatae (PCR essential oil obtained using an improved Clevenger type apparatus were studied. Among the five different PCRs examined the highest yield of essential oil was found in Chachi 2004 (harvested and stored in 2004 and the lowest in Chachi 2008 (harvested and stored in 2008. Fifty three different volatile compounds were determined, including terpenic hydrocarbons, alcohols, aldehydes, ketones and esters. D-limonene, one of terpenes, was the major constituent in PCR. The antioxidant capacity of PCR essential oil varied considerably with the duration of storage time, and the oil from Chachi 1994 has the strongest ferric-reducing antioxidant power. In addition, the essential oil possessed varying degrees of antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, except Streptococcus faecalis, while had no effect on Gram-negative bacteria (Escherichia coli, Enterobacter cloacae.

  12. Internal extracellular bacteria of Diaphorina citri Kuwayama (Hemiptera: Psyllidae), the Asian citrus psyllid.

    Science.gov (United States)

    Kolora, Lakshmi D; Powell, Christopher M; Hunter, W; Bextine, B; Lauzon, C R

    2015-05-01

    The Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an invasive insect pest that transmits Candidatus Liberibacter spp. This insect/pathogen system was first identified in North America in the early 2000's and has become the top threat to the citrus industry. Limited options for management of this problem exist; therefore, innovative pest management strategies are being developed. In this study, we describe the first step toward a paratransgenic approach (also referred to symbiotic control) for control of the insect vector or the pathogen. Culturable bacteria from the gut of Asian Citrus Psyllids were identified using standard culture techniques followed by sequencing of the cultured microorganisms. Further, 454 pyrosequencing of the gut was performed to audit bacterial presence in order to begin to identify any relationship between psyllid symbionts and C. Liberibacter spp. PMID:25645736

  13. Internal extracellular bacteria of Diaphorina citri Kuwayama (Hemiptera: Psyllidae), the Asian citrus psyllid.

    Science.gov (United States)

    Kolora, Lakshmi D; Powell, Christopher M; Hunter, W; Bextine, B; Lauzon, C R

    2015-05-01

    The Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an invasive insect pest that transmits Candidatus Liberibacter spp. This insect/pathogen system was first identified in North America in the early 2000's and has become the top threat to the citrus industry. Limited options for management of this problem exist; therefore, innovative pest management strategies are being developed. In this study, we describe the first step toward a paratransgenic approach (also referred to symbiotic control) for control of the insect vector or the pathogen. Culturable bacteria from the gut of Asian Citrus Psyllids were identified using standard culture techniques followed by sequencing of the cultured microorganisms. Further, 454 pyrosequencing of the gut was performed to audit bacterial presence in order to begin to identify any relationship between psyllid symbionts and C. Liberibacter spp.

  14. 柑橘木虱的研究进展%Research Progress on Diaphorina citri

    Institute of Scientific and Technical Information of China (English)

    陈丽芬; 徐昭焕; 王建国

    2016-01-01

    柑橘木虱(Diaphorina citri)主要危害柑橘等芸香科植物,传播黄龙病菌,给柑橘生产带来极大危害.从柑橘木虱的生物学及生态学特性、防治,柑橘木虱内生菌多样性、其对黄龙病菌的传播机制等方面进行综述,提出木虱寄主选择机理、专性传菌机制和抗性品种筛选是今后防治柑橘木虱的研究重点.

  15. [Bioassay on oviposition repellency of non-preferable plant extracts against citrus red mite Panonychus citri].

    Science.gov (United States)

    Cen, Yijing; Pang, Xiongfei; Zhou, Qiong; Peng, Yuefeng; Xu, Changbao

    2004-09-01

    The oviposition repellency of the alcohol extracts from 50 species of non-preferable plants and azadirachtin against citrus red mite (Panonychus citri) was determined using laboratory bioassays. In choice tests, the extracts from 42 of the 50 plant species and 1% azadirachtin (2000 x) significantly reduced oviposition 1d after treatment. The repellency effect of the extracts from the 42 plant species was better than that of azadirachtin. Mikania micrantha extract had the best result, with an Interference Index of Population Control (IIPC) of 0.087 1 d after treatment, and significantly reduced oviposition for 9 d, while the extracts from Sesbania cannabina, Allium tuberosum, Paederia scandens, Duranta erecta and Dicranopteris pedata also had good effects, with an oviposition repellency of over 70% 1 d after treatment, and significantly reduced oviposition for 4-6 d. The effect became weaker as time went on. None of the extracts showed significant oviposition attraction. PMID:15669510

  16. Control químico de Diaphorina citri Kuwayama (Hemíptera: Psyllidae en lima persa Citrus latifolia Tanaka Chemical control of Diaphorina citri Kuwayama (Hemiptera: Psyllidae in Persian lime Citrus latifolia Tanaka

    Directory of Open Access Journals (Sweden)

    Luis Martín Hernández-Fuentes

    2012-06-01

    Full Text Available A nivel mundial, la citricultura representa una actividad de gran importancia. México ocupa el cuarto lugar mundial en producción. Debido a la introducción y dispersión del vector D. citri en todas las zonas citrí colas de México y la reciente detección de la enfermedad conocida como huanglongbing causada por la bacteria Candidatus Liberibacter asiaticus, es necesaria la evaluación de métodos de control de este insecto. En el año 2010 en Nayarit, México, se realizaron pruebas de efectividad técnica en campo y persistencia de productos químicos de diferente mecanismo de acción contra D. citri en lima persa. Se hicieron dos evaluaciones en fechas distintas. En cada ensayo se evaluó número de ninfas por brote y porcentaje de brotes infestados. De los productos evaluados el dimetoato, imidacloprid y la mezcla de imidacloprid más betaciflutrina ejercieron más de 85 % de control de ninfas durante 27 días después de la aplicación. En los árboles tratados con dimetoato e imidacloprid en dosis de 400 mL y 300 mL ha-¹, respectivamente, se observó 100% de brotes libres de ninfas de D. citri a los 27 días después de la aplicación. El aceite agrícola en dosis de dos y tres L ha-1 ejerció menor control de ninfas de D. citri.Citrus crops represent an outstanding activity at worldwide level. Mexico ranks fourth place in production. Due introduction and dispersion of D. citri vector in all citric zones from Mexico and the newly detected disease known as huanglongbing (HLB caused by Candidatus Liberibacter asiaticus bacteria, assessment of control methods for this bug is required. In 2010, technical effectiveness in field and persistence for different action route against Persian lime D. citri chemical products tests were performed in Nayarit, Mexico. Two assessments were made at different dates. The amount of nymphs per shoot and percentage of infested shoots were assessed in each rehearsal. From evaluated products, dimethoate

  17. Temporal progression of 'Candidatus Liberibacter asiaticus' infection in citrus and acquisition efficiency by Diaphorina citri.

    Science.gov (United States)

    Coletta-Filho, Helvecio D; Daugherty, Matthew P; Ferreira, Cléderson; Lopes, João R S

    2014-04-01

    Over the last decade, the plant disease huanglongbing (HLB) has emerged as a primary threat to citrus production worldwide. HLB is associated with infection by phloem-limited bacteria ('Candidatus Liberibacter' spp.) that are transmitted by the Asian citrus psyllid, Diaphorina citri. Transmission efficiency varies with vector-related aspects (e.g., developmental stage and feeding periods) but there is no information on the effects of host-pathogen interactions. Here, acquisition efficiency of 'Candidatus Liberibacter asiaticus' by D. citri was evaluated in relation to temporal progression of infection and pathogen titer in citrus. We graft inoculated sweet orange trees with 'Ca. L. asiaticus'; then, at different times after inoculation, we inspected plants for HLB symptoms, measured bacterial infection levels (i.e., titer or concentration) in plants, and measured acquisition by psyllid adults that were confined on the trees. Plant infection levels increased rapidly over time, saturating at uniformly high levels (≈10(8) copy number of 16S ribosomal DNA/g of plant tissue) near 200 days after inoculation-the same time at which all infected trees first showed disease symptoms. Pathogen acquisition by vectors was positively associated with plant infection level and time since inoculation, with acquisition occurring as early as the first measurement, at 60 days after inoculation. These results suggest that there is ample potential for psyllids to acquire the pathogen from trees during the asymptomatic phase of infection. If so, this could limit the effectiveness of tree rouging as a disease management tool and would likely explain the rapid spread observed for this disease in the field. PMID:24620723

  18. Temporal progression of 'Candidatus Liberibacter asiaticus' infection in citrus and acquisition efficiency by Diaphorina citri.

    Science.gov (United States)

    Coletta-Filho, Helvecio D; Daugherty, Matthew P; Ferreira, Cléderson; Lopes, João R S

    2014-04-01

    Over the last decade, the plant disease huanglongbing (HLB) has emerged as a primary threat to citrus production worldwide. HLB is associated with infection by phloem-limited bacteria ('Candidatus Liberibacter' spp.) that are transmitted by the Asian citrus psyllid, Diaphorina citri. Transmission efficiency varies with vector-related aspects (e.g., developmental stage and feeding periods) but there is no information on the effects of host-pathogen interactions. Here, acquisition efficiency of 'Candidatus Liberibacter asiaticus' by D. citri was evaluated in relation to temporal progression of infection and pathogen titer in citrus. We graft inoculated sweet orange trees with 'Ca. L. asiaticus'; then, at different times after inoculation, we inspected plants for HLB symptoms, measured bacterial infection levels (i.e., titer or concentration) in plants, and measured acquisition by psyllid adults that were confined on the trees. Plant infection levels increased rapidly over time, saturating at uniformly high levels (≈10(8) copy number of 16S ribosomal DNA/g of plant tissue) near 200 days after inoculation-the same time at which all infected trees first showed disease symptoms. Pathogen acquisition by vectors was positively associated with plant infection level and time since inoculation, with acquisition occurring as early as the first measurement, at 60 days after inoculation. These results suggest that there is ample potential for psyllids to acquire the pathogen from trees during the asymptomatic phase of infection. If so, this could limit the effectiveness of tree rouging as a disease management tool and would likely explain the rapid spread observed for this disease in the field.

  19. Crystal Structure of the FAD-Containing Ferredoxin-NADP+ Reductase from the Plant Pathogen Xanthomonas axonopodis pv. citri

    Directory of Open Access Journals (Sweden)

    María Laura Tondo

    2013-01-01

    Full Text Available We have solved the structure of ferredoxin-NADP(H reductase, FPR, from the plant pathogen Xanthomonas axonopodis pv. citri, responsible for citrus canker, at a resolution of 1.5 Å. This structure reveals differences in the mobility of specific loops when compared to other FPRs, probably unrelated to the hydride transfer process, which contributes to explaining the structural and functional divergence between the subclass I FPRs. Interactions of the C-terminus of the enzyme with the phosphoadenosine of the cofactor FAD limit its mobility, thus affecting the entrance of nicotinamide into the active site. This structure opens the possibility of rationally designing drugs against the X. axonopodis pv. citri phytopathogen.

  20. 广陈皮DNA条形码的初步研究%Preliminary Study on DNA Barcode of Citri Reticulatae Pericarpium from Guangdong

    Institute of Scientific and Technical Information of China (English)

    杨桂玲; 陈晓妮

    2015-01-01

    Pericarpium Citri Reticulatae was from the dry and mature skin of Citrus reticulata Blanco and cultivar. According to different sources of medicinal materials, it can be divided into‘orange’ and‘wide dried tangerine or orange peel’ . Citri Reticulatae Pericarpium from Guangdong from‘Chazhi’ was recognized as Chinese drugs. A method on DNA barcode of Citri Reticulatae Pericarpium from Guangdong was established. The trnH-psbA sequences of different samples of Citri Reticulatae Pericarpium were analyzed in order to establish DNA barcode of Citri Reticulatae Pericarpium from Guangdong. So the trnH-psbA DNA barcode can be used to preliminary identification of Citri Reticulatae Pericarpium from Guangdong.%陈皮( Citri Reticulatae Pericarpium )为芸香科植物橘Citrus Reticulata Blanco及其栽培变种的干燥成熟果皮。根据药材来源不同又可分为“陈皮”和“广陈皮”。其中“广陈皮”是变种的茶枝柑果皮,为公认的道地药材。本文拟在分子水平建立广陈皮的DNA条形码,并对来源不同的陈皮样本在trnH-psbA序列进行分析,建立广陈皮的DNA序列。结果表明广陈皮样本与橙类果皮样本之间有明显的差异。因此,判断trnH-psbA序列DNA条形码可用于初步鉴别广陈皮。

  1. Essential Oil Variation from Twenty Two Genotypes of Citrus in Brazil—Chemometric Approach and Repellency Against Diaphorina citri Kuwayama

    Directory of Open Access Journals (Sweden)

    Moacir dos Santos Andrade

    2016-06-01

    Full Text Available The chemical composition of volatile oils from 22 genotypes of Citrus and related genera was poorly differentiated, but chemometric techniques have clarified the relationships between the 22 genotypes, and allowed us to understand their resistance to D. citri. The most convincing similarities include the synthesis of (Z-β-ocimene and (E-caryophyllene for all 11 genotypes of group A. Genotypes of group B are not uniformly characterized by essential oil compounds. When stimulated with odor sources of 22 genotypes in a Y-tube olfactometer D. citri preferentially entered the arm containing the volatile oils of Murraya paniculata, confirming orange jasmine as its best host. C. reticulata × C. sinensis was the least preferred genotype, and is characterized by the presence of phytol, (Z-β-ocimene, and β-elemene, which were not found in the most preferred genotype. We speculate that these three compounds may act as a repellent, making these oils less attractive to D. citri.

  2. Sobre o condicionamento alimentar na cochonilha-branca, Planococcus citri (Risso (Hemiptera: pseudococcidae Regarding to host conditioning in citrus mealybug Planococcus citri (Risso (Hemiptera: pseudococcidae

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    Lenira Viana Costa Santa-Cecília

    2013-03-01

    Full Text Available Estudos do comportamento alimentar mediante a técnica de "Electrical Penetration Graphs" (EPG das cochonilhas-farinhentas (Pseudococcidae provenientes de um hospedeiro de criação alternativo têm mostrado que esses insetos não atingem ou demoram cerca de 9 horas para alcançar a fase floemática. Por outro lado, aqueles provenientes do hospedeiro-fonte atingem a fase floemática mais rapidamente e apresentam maior frequência de alimentação nos vasos crivados. Esses resultados indicam a presença do fenômeno de condicionamento alimentar, ainda não demonstrado em cochonilhas. Assim, o presente trabalho teve como objetivo determinar a existência desse fenômeno em Planococcus citri (Risso (Hemiptera: Pseudococcidae. Foram realizados testes de livre escolha, monitoramento eletrônico (EPG e estudos de alguns parâmetros biológicos. Em todos os experimentos, o cafeeiro (Coffea arabica L., os citros (Citrus sinensis L. e abóbora (Cucurbita maxima L. foram utilizados como substratos de criação (fonte da cochonilha, sendo os tratamentos constituídos pela combinação entre os hospedeiros-fonte e os hospedeiros receptores (café e citros. O teste de escolha entre cafeeiro e citros nas primeiras 72 horas mostrou que as cochonilhas criadas em cafeeiro apresentaram preferência pelo cafeeiro; aquelas originadas dos citros mostraram uma tendência, embora não significativa, em selecionar os citros em relação ao cafeeiro e aquelas criadas em abóbora não mostraram preferência por nenhum dos hospedeiros. Os estudos do comportamento alimentar mediante o monitoramento eletrônico (EPG mostraram que a fase floemática, considerada como a fase de aceitação do hospedeiro, foi mais frequente em cafeeiro, seja com cochonilhas oriundas deste substrato, seja de citros. Aqueles insetos mantidos em abóbora e transferidos para o cafeeiro ou citros apresentaram excepcionalmente ou não apresentaram nenhuma fase floemática, respectivamente. A

  3. Antennal and Abdominal Transcriptomes Reveal Chemosensory Genes in the Asian Citrus Psyllid, Diaphorina citri.

    Science.gov (United States)

    Wu, Zhongzhen; Zhang, He; Bin, Shuying; Chen, Lei; Han, Qunxin; Lin, Jintian

    2016-01-01

    The Asian citrus psyllid, Diaphorina citri is the principal vector of the highly destructive citrus disease called Huanglongbing (HLB) or citrus greening, which is a major threat to citrus cultivation worldwide. More effective pest control strategies against this pest entail the identification of potential chemosensory proteins that could be used in the development of attractants or repellents. However, the molecular basis of olfaction in the Asian citrus psyllid is not completely understood. Therefore, we performed this study to analyze the antennal and abdominal transcriptome of the Asian citrus psyllid. We identified a large number of transcripts belonging to nine chemoreception-related gene families and compared their expression in male and female adult antennae and terminal abdomen. In total, 9 odorant binding proteins (OBPs), 12 chemosensory proteins (CSPs), 46 odorant receptors (ORs), 20 gustatory receptors (GRs), 35 ionotropic receptors (IRs), 4 sensory neuron membrane proteins (SNMPs) and 4 different gene families encoding odorant-degrading enzymes (ODEs): 80 cytochrome P450s (CYPs), 12 esterase (ESTs), and 5 aldehyde dehydrogenases (ADE) were annotated in the D. citri antennal and abdominal transcriptomes. Our results revealed that a large proportion of chemosensory genes exhibited no distinct differences in their expression patterns in the antennae and terminal abdominal tissues. Notably, RNA sequencing (RNA-seq) data and quantitative real time-PCR (qPCR) analyses showed that 4 DictOBPs, 4 DictCSPs, 4 DictIRs, 1 DictSNMP, and 2 DictCYPs were upregulated in the antennae relative to that in terminal abdominal tissues. Furthermore, 2 DictOBPs (DictOBP8 and DictOBP9), 2 DictCSPs (DictOBP8 and DictOBP12), 4 DictIRs (DictIR3, DictIR6, DictIR10, and DictIR35), and 1 DictCYP (DictCYP57) were expressed at higher levels in the male antennae than in the female antennae. Our study provides the first insights into the molecular basis of chemoreception in this insect

  4. Antennal and Abdominal Transcriptomes Reveal Chemosensory Genes in the Asian Citrus Psyllid, Diaphorina citri.

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    Zhongzhen Wu

    Full Text Available The Asian citrus psyllid, Diaphorina citri is the principal vector of the highly destructive citrus disease called Huanglongbing (HLB or citrus greening, which is a major threat to citrus cultivation worldwide. More effective pest control strategies against this pest entail the identification of potential chemosensory proteins that could be used in the development of attractants or repellents. However, the molecular basis of olfaction in the Asian citrus psyllid is not completely understood. Therefore, we performed this study to analyze the antennal and abdominal transcriptome of the Asian citrus psyllid. We identified a large number of transcripts belonging to nine chemoreception-related gene families and compared their expression in male and female adult antennae and terminal abdomen. In total, 9 odorant binding proteins (OBPs, 12 chemosensory proteins (CSPs, 46 odorant receptors (ORs, 20 gustatory receptors (GRs, 35 ionotropic receptors (IRs, 4 sensory neuron membrane proteins (SNMPs and 4 different gene families encoding odorant-degrading enzymes (ODEs: 80 cytochrome P450s (CYPs, 12 esterase (ESTs, and 5 aldehyde dehydrogenases (ADE were annotated in the D. citri antennal and abdominal transcriptomes. Our results revealed that a large proportion of chemosensory genes exhibited no distinct differences in their expression patterns in the antennae and terminal abdominal tissues. Notably, RNA sequencing (RNA-seq data and quantitative real time-PCR (qPCR analyses showed that 4 DictOBPs, 4 DictCSPs, 4 DictIRs, 1 DictSNMP, and 2 DictCYPs were upregulated in the antennae relative to that in terminal abdominal tissues. Furthermore, 2 DictOBPs (DictOBP8 and DictOBP9, 2 DictCSPs (DictOBP8 and DictOBP12, 4 DictIRs (DictIR3, DictIR6, DictIR10, and DictIR35, and 1 DictCYP (DictCYP57 were expressed at higher levels in the male antennae than in the female antennae. Our study provides the first insights into the molecular basis of chemoreception in this

  5. Antennal and Abdominal Transcriptomes Reveal Chemosensory Genes in the Asian Citrus Psyllid, Diaphorina citri.

    Science.gov (United States)

    Wu, Zhongzhen; Zhang, He; Bin, Shuying; Chen, Lei; Han, Qunxin; Lin, Jintian

    2016-01-01

    The Asian citrus psyllid, Diaphorina citri is the principal vector of the highly destructive citrus disease called Huanglongbing (HLB) or citrus greening, which is a major threat to citrus cultivation worldwide. More effective pest control strategies against this pest entail the identification of potential chemosensory proteins that could be used in the development of attractants or repellents. However, the molecular basis of olfaction in the Asian citrus psyllid is not completely understood. Therefore, we performed this study to analyze the antennal and abdominal transcriptome of the Asian citrus psyllid. We identified a large number of transcripts belonging to nine chemoreception-related gene families and compared their expression in male and female adult antennae and terminal abdomen. In total, 9 odorant binding proteins (OBPs), 12 chemosensory proteins (CSPs), 46 odorant receptors (ORs), 20 gustatory receptors (GRs), 35 ionotropic receptors (IRs), 4 sensory neuron membrane proteins (SNMPs) and 4 different gene families encoding odorant-degrading enzymes (ODEs): 80 cytochrome P450s (CYPs), 12 esterase (ESTs), and 5 aldehyde dehydrogenases (ADE) were annotated in the D. citri antennal and abdominal transcriptomes. Our results revealed that a large proportion of chemosensory genes exhibited no distinct differences in their expression patterns in the antennae and terminal abdominal tissues. Notably, RNA sequencing (RNA-seq) data and quantitative real time-PCR (qPCR) analyses showed that 4 DictOBPs, 4 DictCSPs, 4 DictIRs, 1 DictSNMP, and 2 DictCYPs were upregulated in the antennae relative to that in terminal abdominal tissues. Furthermore, 2 DictOBPs (DictOBP8 and DictOBP9), 2 DictCSPs (DictOBP8 and DictOBP12), 4 DictIRs (DictIR3, DictIR6, DictIR10, and DictIR35), and 1 DictCYP (DictCYP57) were expressed at higher levels in the male antennae than in the female antennae. Our study provides the first insights into the molecular basis of chemoreception in this insect

  6. Polymerase chain reaction-restriction fragment length polymorphism method to distinguish three mealybug groups within the Planococcus citri-P. minor species complex (Hemiptera: Coccoidea: Pseudococcidae).

    Science.gov (United States)

    Rung, A; Miller, D R; Scheffer, S J

    2009-02-01

    The mealybug species Planococcus citri (Risso) and Planococcus minor (Maskell) (Hemiptera: Coccoidea: Pseudococcidae) have special significance to U.S. quarantine and U.S. agriculture. Commonly intercepted at U.S. ports-of-entry, they are difficult to identify based on morphological characters. This study presents a molecular method for distinguishing P. citri, P. minor, and a genetically distinct group that is morphologically identical to P. citri, from Hawaii. This method uses polymerase chain reaction (PCR) followed by restriction fragment polymorphism analysis (RFLP) using the restriction enzymes BspH1, BsmH1, and HpH1. The resulting band patterns can be visualized in a 2% agarose gel and are sufficient to differentiate between the three entities mentioned above. PCR-RFLP diagnostics can be used for all life stages and is cheaper and faster than DNA sequencing.

  7. Patogenicidade de Beauveria bassiana ao psilídeo Diaphorina citri e compatibilidade do fungo com produtos fitossanitários Beauveria bassiana pathogenicity to Diaphorina citri and compatibility of the fungus with phytosanitary products

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    Ana Paula Ferreira Pinto

    2012-12-01

    Full Text Available O objetivo deste trabalho foi avaliar a patogenicidade de Beauveria bassiana a ninfas de Diaphorina citri (Hemiptera: Psyllidae e verificar a compatibilidade do fungo com produtos fitossanitários e sua persistência em plantas de citros. Ninfas de D. citri foram pulverizadas com B. bassiana, nas concentrações 5x10(6, 1x10(7, 5x10(7, 1x10(8, 5x10(8 e 1x10(9 conídios mL-1, para determinação da concentração letal. Para avaliação da compatibilidade do fungo com produtos fitossanitários, extrato de nim e cinco inseticidas de quatro grupos químicos diferentes foram incorporados individualmente ao meio de cultura BDA em que o fungo foi cultivado. Avaliaram-se o crescimento vegetativo, a esporulação e a viabilidade do entomopatógeno. Plantas de citros, mantidas em casa de vegetação, foram tratadas primeiramente com os produtos fitossanitários e depois com o entomopatógeno. Avaliaram-se os tempos de exposição de 24 horas e de 7 e 14 dias. O fungo foi patogênico às ninfas de D. citri; a CL50 foi de 0,4x10(7 e a CL90 de 6,7x10(7 conidios mL-1, no décimo dia de avaliação. Em laboratório, os produtos fitosssanitários reduzem o crescimento do fungo. Em casa de vegetação, os produtos não afetam a sobrevivência do fungo nas plantas de citros.The objective of this work was to evaluate the pathogenicity of Beauveria bassiana to Diaphorina citri (Hemiptera: Psyllidae nymphs, and to check the compatibility of the fungus with phytosanitary products, and its persistence in citrus plants. Nymphs of D. citri were sprayed with B. bassiana in the concentrations 5x10(6, 1x10(7, 5x10(7, 1x10(8, 5x10(8 and 1x10(9 conidia mL-1 for lethal concentration determination. In order to evaluate the compatibility of the phytosanitary products with the fungus, neem extract and five insecticides of four different chemical groups were individually added to PDA culture medium, in which the fungus was cultivated. Vegetative growth, sporulation and viability

  8. Two-Spotted Ladybeetle Adalia bipunctata L. (Coleoptera: Coccinellidae): A Commercially Available Predator to Control Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Khan, Azhar A; Qureshi, Jawwad A; Afzal, Muhammad; Stansly, Philip A

    2016-01-01

    The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) is an economically important pest of citrus because it serves as a vector of the causal pathogens of huanglongbing (HLB) also known as citrus greening disease. The increased use of insecticides for control of D. citri negatively impacts several natural enemies including some effective ladybeetle species which are not available commercially. The two-spotted ladybeetle, Adalia bipunctata (Coleoptera: Coccinellidae) is found in some crop and forest ecosystems of Asia, Europe and North America and available commercially. It is known to attack aphids and mealybugs but there are no published records of feeding on psyllids. We evaluated suitability and preference of A. bipunctata for nymphs of D. citri compared to corn leaf aphid Rhopalosiphum maidis (Hemiptera: Aphididae) a global pest of cereal crops and prey for many predaceous insects. We also compared development and reproduction of A. bipunctata on these two species with frozen eggs of the Mediterranean flour moth Ephestia kuehniella (Lepidoptera: Pyralidae) at 25°C. Initially, more D. citri than R. maidis nymphs were consumed in the no-choice tests although final consumption by larva and adult of A. bipunctata did not differ in the choice and no-choice tests. Larval development was prolonged by one day on D. citri compared to R. maidis nymphs but did not differ between either of these diets and E. kuehniella. Larval survival to adult averaged 93-100% and was not impacted by diet. Adult life span did not differ between diets although those on D. citri and R. maidis nymphs weighed less and produced fewer but more fertile eggs than on E. kuehniella eggs. Significant reduction of D. citri nymphs averaging 54% was observed in colonies caged with adult A. bipunctata on field planted citrus. R° (net reproductive rate) was least for beetles fed R. maidis, but otherwise there were no significant differences in demographic parameters. Successful

  9. Two-Spotted Ladybeetle Adalia bipunctata L. (Coleoptera: Coccinellidae): A Commercially Available Predator to Control Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae)

    Science.gov (United States)

    Afzal, Muhammad; Stansly, Philip A.

    2016-01-01

    The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) is an economically important pest of citrus because it serves as a vector of the causal pathogens of huanglongbing (HLB) also known as citrus greening disease. The increased use of insecticides for control of D. citri negatively impacts several natural enemies including some effective ladybeetle species which are not available commercially. The two-spotted ladybeetle, Adalia bipunctata (Coleoptera: Coccinellidae) is found in some crop and forest ecosystems of Asia, Europe and North America and available commercially. It is known to attack aphids and mealybugs but there are no published records of feeding on psyllids. We evaluated suitability and preference of A. bipunctata for nymphs of D. citri compared to corn leaf aphid Rhopalosiphum maidis (Hemiptera: Aphididae) a global pest of cereal crops and prey for many predaceous insects. We also compared development and reproduction of A. bipunctata on these two species with frozen eggs of the Mediterranean flour moth Ephestia kuehniella (Lepidoptera: Pyralidae) at 25°C. Initially, more D. citri than R. maidis nymphs were consumed in the no-choice tests although final consumption by larva and adult of A. bipunctata did not differ in the choice and no-choice tests. Larval development was prolonged by one day on D. citri compared to R. maidis nymphs but did not differ between either of these diets and E. kuehniella. Larval survival to adult averaged 93–100% and was not impacted by diet. Adult life span did not differ between diets although those on D. citri and R. maidis nymphs weighed less and produced fewer but more fertile eggs than on E. kuehniella eggs. Significant reduction of D. citri nymphs averaging 54% was observed in colonies caged with adult A. bipunctata on field planted citrus. R° (net reproductive rate) was least for beetles fed R. maidis, but otherwise there were no significant differences in demographic parameters. Successful

  10. Remote Sensing of Low and Mid-Latitude Ionospheric Disturbances During Solar Minimum Using CITRIS and CERTO Measurements of TEC and Radio Scintillation

    Science.gov (United States)

    Siefring, C. L.; Bernhardt, P. A.

    2010-12-01

    Unique data on ionospheric plasma disturbances from the Naval Research Laboratory CITRIS (Scintillation and TEC Receiver in Space) instrument will be presented. CITRIS is a multi-band receiver that recorded TEC (Total Electron Content) and radio scintillations from Low-Earth Orbit (LEO) on STPSat1. The 555+/5 km altitude 35° inclination orbit covers low and mid-latitudes. The measurements require propagation from a transmitter to a receiver through the F-region plasma. CITRIS used both 1) satellite beacons in LEO, such as the NRL CERTO (Coherent Electromagnetic Radio TOmography) three-frequency beacons transmitting at 150/400/1067 MHz and 2) the French global network of ground-based DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) beacons transmitting at 401.25 and 2036.25 MHz. CITRIS was operated in a complementary fashion with the C/NOFS satellite during most of its first year of operations; C/NOFS carries CERTO beacon along with in-situ diagnostics. CITRIS and ground receivers can simultaneously measure TEC and scintillations on different paths using CERTO on C/NOFS. When C/NOFS is not in view, CITRIS makes measurements from DORIS beacons and other LEO satellites. Because of the orbits CITRIS will always make measurements at the same longitude within 48 min of C/NOFS. The ability to look at multiple paths is unique and useful for studying the spatial extent and time duration of disturbances. The combination of TEC and scintillation measurements provides information on a range of scale-sizes from >1 km to about 100 m. The joint data set on plasma structures at low-latitudes is a focus of our presentation, with the addition of comparisons to CITRIS data taken at mid-latitude. Several types of irregularities have been studied including Spread-F and the newly discovered dawn-side depletions. The data covers large portions of the Earth (including the Pacific, African and South American sectors) during an unusually quite portion of the most

  11. Two-Spotted Ladybeetle Adalia bipunctata L. (Coleoptera: Coccinellidae): A Commercially Available Predator to Control Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Khan, Azhar A; Qureshi, Jawwad A; Afzal, Muhammad; Stansly, Philip A

    2016-01-01

    The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) is an economically important pest of citrus because it serves as a vector of the causal pathogens of huanglongbing (HLB) also known as citrus greening disease. The increased use of insecticides for control of D. citri negatively impacts several natural enemies including some effective ladybeetle species which are not available commercially. The two-spotted ladybeetle, Adalia bipunctata (Coleoptera: Coccinellidae) is found in some crop and forest ecosystems of Asia, Europe and North America and available commercially. It is known to attack aphids and mealybugs but there are no published records of feeding on psyllids. We evaluated suitability and preference of A. bipunctata for nymphs of D. citri compared to corn leaf aphid Rhopalosiphum maidis (Hemiptera: Aphididae) a global pest of cereal crops and prey for many predaceous insects. We also compared development and reproduction of A. bipunctata on these two species with frozen eggs of the Mediterranean flour moth Ephestia kuehniella (Lepidoptera: Pyralidae) at 25°C. Initially, more D. citri than R. maidis nymphs were consumed in the no-choice tests although final consumption by larva and adult of A. bipunctata did not differ in the choice and no-choice tests. Larval development was prolonged by one day on D. citri compared to R. maidis nymphs but did not differ between either of these diets and E. kuehniella. Larval survival to adult averaged 93-100% and was not impacted by diet. Adult life span did not differ between diets although those on D. citri and R. maidis nymphs weighed less and produced fewer but more fertile eggs than on E. kuehniella eggs. Significant reduction of D. citri nymphs averaging 54% was observed in colonies caged with adult A. bipunctata on field planted citrus. R° (net reproductive rate) was least for beetles fed R. maidis, but otherwise there were no significant differences in demographic parameters. Successful

  12. Molecular cloning and characterization of a microsatellite locus found in an RAPD marker of a spider mite, Panonychus citri (Acari: Tetranychidae).

    Science.gov (United States)

    Osakabe, M; Hinomoto, N; Toda, S; Komazaki, S; Goka, K

    2000-01-01

    Genetic markers were searched using PCR with 40 kinds of decanucleotide primers to investigate DNA polymorphism in Panonychus citri. A region consisting of a variable number of CT tandem repeats (microsatellite) was found in a fragment amplified with the OPB10 primer. The microsatellite differed in size by ca. 100bp among several P. citri populations screened and was derived from at least seven alleles. This region was characteristic of P. mori and P. osmanthi, but was lacking in P. ulmi. The flanking regions were highly conserved among these species. PMID:11156164

  13. The effect of Leptomastix dactylopii parasitism and venom injection on host Planococcus citri

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    D Battaglia

    2014-10-01

    Full Text Available One of the major alterations observed in mealybug Planococcus citri parasitized by Leptomastix dactylopii is a strong reduction of laid eggs, which is evident soon after parasitization. Venom injection in unparasitized hosts determines a drastic reduction of fecundity indicating that this female secretion injected at the oviposition plays a key-role in host regulation. In order to assess the impact of parasitism and venom injection on host reproductive tissues, ovaries were dissected at different time intervals after these treatments and observed by light and transmission electron microscopy. The developing eggs showed clear symptoms of degeneration, already half an hour after parasitization or venom injection. Heat and protease treatments of venom nearly suppressed its effects on host reproduction, indicating that proteins are likely responsible for the observed alterations. The electrophoretic profile of venom proteins covers a wide range of molecular masses between 15 to 200 kDa but five major bands having a molecular mass of about 27, 30, 40, 90 and 120 kDa respectively were more evident. Moreover, to establish any parasitoid preference in host selection, among the adult female mealybugs at different stages of maturation and a possible relation with fecundity reduction in the host, the parasitoid behavior was observed.

  14. The GC/MS Analysis of Volatile Components Extracted by Different Methods from Exocarpium Citri Grandis

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    Zhisheng Xie

    2013-01-01

    Full Text Available Volatile components from Exocarpium Citri Grandis (ECG were, respectively, extracted by three methods, that is, steam distillation (SD, headspace solid-phase microextraction (HS-SPME, and solvent extraction (SE. A total of 81 compounds were identified by gas chromatography-mass spectrometry including 77 (SD, 56 (HS-SPME, and 48 (SE compounds, respectively. Despite of the extraction method, terpenes (39.98~57.81% were the main volatile components of ECG, mainly germacrene-D, limonene, 2,6,8,10,14-hexadecapentaene, 2,6,11,15-tetramethyl-, (E,E,E-, and trans-caryophyllene. Comparison was made among the three methods in terms of extraction profile and property. SD relatively gave an entire profile of volatile in ECG by long-time extraction; SE enabled the analysis of low volatility and high molecular weight compounds but lost some volatiles components; HS-SPME generated satisfactory extraction efficiency and gave similar results to those of SD at analytical level when consuming less sample amount, shorter extraction time, and simpler procedure. Although SD and SE were treated as traditionally preparative extractive techniques for volatiles in both small batches and large scale, HS-SPME coupled with GC/MS could be useful and appropriative for the rapid extraction and qualitative analysis of volatile components from medicinal plants at analytical level.

  15. Identification of anti-asthmatic compounds in Pericarpium citri reticulatae and evaluation of their synergistic effects

    Institute of Scientific and Technical Information of China (English)

    Qian SHI; Ze LIU; Yang YANG; Peng GENG; Yuan-yuan ZHU; Qi ZHANG; Fang BAI; Gang BAI

    2009-01-01

    Aim: To investigate the anti-asthmatic mechanisms of the traditional Chinese medicine Pericarpium citri reticulatae (PCR).Methods: The alkaloid section (AS) of PCR was extracted using an ion exchange resin, separated, and purified into different fractions by semi-preparative HPLC. These fractions were screened for beta2-adrenergic receptor (β2AR) agonistic activity using rat β2AR-transfected CHO-CRE-EGFP cells. AS and its isolated components were characterized by ultra-performance liquid chromatography/quadrupole time-of-flight MS (UPLC/Q-Tof MS) and were evaluated for their spasmolytic and antitussive activities both in vitro and in vivo in a guinea pig model.Results: We demonstrated that the AS component responsible for activating β2AR signaling was synephrine. Both AS and synephrine showed significant spasmolytic effects on acetylcholine chloride (ACh)-induced contractions in isolated guinea pig trachea, and they protected against histamine-induced experimental asthma by prolonging the latent period. We further identified stachydrine as the antitussive component that could significantly reduce citric acid-induced coughing. The combination of these two bioactive compounds had a more potent spasmolytic activity in comparison with the single use of synephrine or stachydrine.Conclusion: We conclude that synephrine and stachydrine are the key components of AS that mediate asthma relief due to their synergism when used in combination.

  16. Genomic insights into the evolutionary origin of Xanthomonas axonopodis pv. citri and its ecological relatives.

    Science.gov (United States)

    Midha, Samriti; Patil, Prabhu B

    2014-10-01

    Xanthomonas axonopodis pv. citri (Xac) is the causal agent of citrus bacterial canker (CBC) and is a serious problem worldwide. Like CBC, several important diseases in other fruits, such as mango, pomegranate, and grape, are also caused by Xanthomonas pathovars that display remarkable specificity toward their hosts. While citrus and mango diseases were documented more than 100 years ago, the pomegranate and grape diseases have been known only since the 1950s and 1970s, respectively. Interestingly, diseases caused by all these pathovars were noted first in India. Our genome-based phylogenetic studies suggest that these diverse pathogens belong to a single species and these pathovars may be just a group of rapidly evolving strains. Furthermore, the recently reported pathovars, such as those infecting grape and pomegranate, form independent clonal lineages, while the citrus and mango pathovars that have been known for a long time form one clonal lineage. Such an understanding of their phylogenomic relationship has further allowed us to understand major and unique variations in the lineages that give rise to these pathovars. Whole-genome sequencing studies including ecological relatives from their putative country of origin has allowed us to understand the evolutionary history of Xac and other pathovars that infect fruits.

  17. Botanicals, selective insecticides, and predators to control Diaphorina citri (Hemiptera: Liviidae) in citrus orchards.

    Science.gov (United States)

    Khan, Azhar A; Afzal, Muhammad; Qureshi, Jawwad A; Khan, Arif M; Raza, Abubakar M

    2014-12-01

    The Asian citrus psyllid (ACP) Diaphorina citri Kuwayama vectors pathogens that cause huanglongbing (HLB) or citrus greening devastating and economically important disease present in most citrus growing regions. Young citrus shoots are required for psyllid reproduction and development. During winter citrus trees produce little or no new growth. Overwintering adults reproduce in spring on newly emerging shoots also attractive to other pests and beneficial insects. Botanicals and relatively selective insecticides could help to conserve beneficial insects and reduce pest resistance to insecticides. Sprays of Azadirachtin (Neem), Tropane (Datura), Spirotetramat, Spinetoram, and broad-spectrum Imidacloprid were evaluated to control ACP in spring and summer on 10-year-old "Kinow" Citrus reticulata Blanco trees producing new growth. Psyllid populations were high averaging 5-9 nymphs or adults per sample before treatment application. Nymphs or adults were significantly reduced to 0.5-1.5 per sample in all treatments for 3 weeks, average 61%-83% reduction. No significant reduction in ladybeetles Adalia bipunctata, Aneglei scardoni, Cheilomenes sexmaculata, and Coccinella septempunctata was observed. Syrphids, spiders and green lacewings were reduced in treated trees except with Tropane. Studies are warranted to assess impact of these predators on ACP and interaction with insecticides. Observed reduction in ACP populations may not be enough considering its reproductive potential and role in the spread of HLB. Follow-up sprays may be required to achieve additional suppression using rotations of different insecticides. PMID:25205398

  18. Resistance of Citrus and Related Genera to Diaphorina citri Kuwayama (Hemiptera: Liviidae).

    Science.gov (United States)

    Borgoni, P C; Vendramim, J D; Lourencão, A L; Machado, M A

    2014-10-01

    The present study was developed to evaluate the resistance of the following genotypes of Citrus and related genera to this pest: 'Pera,' 'Natal', and 'Washington Navel' oranges (Citrus sinensis), 'Marsh Seedless' grapefruit (Citrus paradisi), hardy orange 'Rubidoux' (Poncirus trifoliata), kumquat (Fortunella margarita Swingle), citrumelo 'Swingle' (C. paradisi x P. trifoliata), and citrange 'Troyer' (P. trifoliata x C. sinensis). The experiments were performed in greenhouses with plants grafted onto 'Rangpur' lime (Citrus limonia) and placed individually in voile cages. The preference for oviposition in a no-choice test, and the effect of genotype were evaluated. The egg-adult cycle was monitored to determine the effect of genotype on the biology of the insect. Poncirus 'Rubidoux' was the least preferred genotype for oviposition; reduced number of eggs was also found to occur on citrange 'Troyer', and 'Marsh Seedless' was the genotype with the most eggs. No significant variation in the duration of the embryonic period was observed; however, a difference in the viability of eggs was found, with the lowest egg viabilities on 'Swingle.' Kumquat and 'Marsh Seedless' genotypes were correlated with increased durations of the nymphal phase, however, there was no difference in the survival of this phase. Fecundity of females on 'Troyer', 'Swingle', and kumquat was reduced. Considering all of the evaluated parameters, it was concluded that cultivars of sweet orange are the most susceptible genotypes to Diaphorina citri. Regarding oviposition, P. trifoliata 'Rubidoux' showed resistance of the antixenosis type. PMID:27193957

  19. Species clarification of Isaria isolates used as biocontrol agents against Diaphorina citri (Hemiptera: Liviidae) in Mexico.

    Science.gov (United States)

    Gallou, Adrien; Serna-Domínguez, María G; Berlanga-Padilla, Angélica M; Ayala-Zermeño, Miguel A; Mellín-Rosas, Marco A; Montesinos-Matías, Roberto; Arredondo-Bernal, Hugo C

    2016-03-01

    Entomopathogenic fungi belonging to the genus Isaria (Hypocreales: Cordycipitaceae) are promising candidates for microbial control of insect pests. Currently, the Mexican government is developing a biological control program based on extensive application of Isaria isolates against Diaphorina citri (Hemiptera: Liviidae), a vector of citrus huanglongbing disease. Previous research identified three promising Isaria isolates (CHE-CNRCB 303, 305, and 307; tentatively identified as Isaria fumosorosea) from Mexico. The goal of this work was to obtain a complete morphological and molecular characterization of these isolates. Comparative analysis of morphology established that the isolates showed similar characteristics to Isaria javanica. Multi-gene analysis confirmed the morphological identification by including the three isolates within the I. javanica clade. Additionally, this work demonstrated the misidentifications of three other Isaria isolates (CHE-CNRCB 310 and 324: I. javanica, formerly I. fumosorosea; CHE-CNRCB 393: I. fumosorosea, formerly Isaria farinosa), underlying the need for a full and correct characterization of an isolate before developing a biological control program. Finally, the inter-simple sequence repeat (ISSR) genotyping method revealed that the CHE-CNRCB 303, 305, and 307 isolates belong to three different genotypes. This result indicates that ISSR markers could be used as a tool to monitor their presence in field conditions. PMID:26895870

  20. Exposure to Guava Affects Citrus Olfactory Cues and Attractiveness to Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Barman, Jagadish Chandra; Campbell, Stuart A; Zeng, Xinnian

    2016-06-01

    Intercropping can reduce agricultural pest incidence, and represents an important sustainable alternative to conventional pest control methods. Understanding the ecological mechanisms for intercropping could help optimize its use, particularly in tropical systems which present a large number of intercropping possibilities. Citrus is threatened worldwide by greening disease (huanglongbing, HLB) vectored by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). Control of HLB and citrus psyllid can be partially achieved through intercropping with guava, Psidium guajava L., but the mechanisms remain unclear. We tested the hypothesis that guava olfactory cues affect psyllid behavior by altering the attractiveness of citrus through plant-plant interactions. In choice and no-choice cage experiments, psyllid settlement was reduced on citrus shoots that had been exposed to guava shoot odors for at least 2 h. In Y-tube olfactometer experiments, psyllids oriented to odors of unexposed, compared with guava-exposed, citrus shoots. These behavioral results indicate that a mechanism for the success of guava intercropping for sustainable, ecological disease management may be the indirect effect of guava on citrus attractiveness. PMID:27247354

  1. Botanicals, selective insecticides, and predators to control Diaphorina citri (Hemiptera: Liviidae) in citrus orchards.

    Science.gov (United States)

    Khan, Azhar A; Afzal, Muhammad; Qureshi, Jawwad A; Khan, Arif M; Raza, Abubakar M

    2014-12-01

    The Asian citrus psyllid (ACP) Diaphorina citri Kuwayama vectors pathogens that cause huanglongbing (HLB) or citrus greening devastating and economically important disease present in most citrus growing regions. Young citrus shoots are required for psyllid reproduction and development. During winter citrus trees produce little or no new growth. Overwintering adults reproduce in spring on newly emerging shoots also attractive to other pests and beneficial insects. Botanicals and relatively selective insecticides could help to conserve beneficial insects and reduce pest resistance to insecticides. Sprays of Azadirachtin (Neem), Tropane (Datura), Spirotetramat, Spinetoram, and broad-spectrum Imidacloprid were evaluated to control ACP in spring and summer on 10-year-old "Kinow" Citrus reticulata Blanco trees producing new growth. Psyllid populations were high averaging 5-9 nymphs or adults per sample before treatment application. Nymphs or adults were significantly reduced to 0.5-1.5 per sample in all treatments for 3 weeks, average 61%-83% reduction. No significant reduction in ladybeetles Adalia bipunctata, Aneglei scardoni, Cheilomenes sexmaculata, and Coccinella septempunctata was observed. Syrphids, spiders and green lacewings were reduced in treated trees except with Tropane. Studies are warranted to assess impact of these predators on ACP and interaction with insecticides. Observed reduction in ACP populations may not be enough considering its reproductive potential and role in the spread of HLB. Follow-up sprays may be required to achieve additional suppression using rotations of different insecticides.

  2. The GC/MS Analysis of Volatile Components Extracted by Different Methods from Exocarpium Citri Grandis.

    Science.gov (United States)

    Xie, Zhisheng; Liu, Qundi; Liang, Zhikun; Zhao, Mingqian; Yu, Xiaoxue; Yang, Depo; Xu, Xinjun

    2013-01-01

    Volatile components from Exocarpium Citri Grandis (ECG) were, respectively, extracted by three methods, that is, steam distillation (SD), headspace solid-phase microextraction (HS-SPME), and solvent extraction (SE). A total of 81 compounds were identified by gas chromatography-mass spectrometry including 77 (SD), 56 (HS-SPME), and 48 (SE) compounds, respectively. Despite of the extraction method, terpenes (39.98~57.81%) were the main volatile components of ECG, mainly germacrene-D, limonene, 2,6,8,10,14-hexadecapentaene, 2,6,11,15-tetramethyl-, (E,E,E)-, and trans-caryophyllene. Comparison was made among the three methods in terms of extraction profile and property. SD relatively gave an entire profile of volatile in ECG by long-time extraction; SE enabled the analysis of low volatility and high molecular weight compounds but lost some volatiles components; HS-SPME generated satisfactory extraction efficiency and gave similar results to those of SD at analytical level when consuming less sample amount, shorter extraction time, and simpler procedure. Although SD and SE were treated as traditionally preparative extractive techniques for volatiles in both small batches and large scale, HS-SPME coupled with GC/MS could be useful and appropriative for the rapid extraction and qualitative analysis of volatile components from medicinal plants at analytical level. PMID:24349825

  3. Odorants for surveillance and control of the Asian Citrus Psyllid (Diaphorina citri.

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    Iliano V Coutinho-Abreu

    Full Text Available BACKGROUND: The Asian Citrus Psyllid (ACP, Diaphorina citri, can transmit the bacterium Candidatus Liberibacter while feeding on citrus flush shoots. This bacterium causes Huanglongbing (HLB, a major disease of citrus cultivation worldwide necessitating the development of new tools for ACP surveillance and control. The olfactory system of ACP is sensitive to variety of odorants released by citrus plants and offers an opportunity to develop new attractants and repellents. RESULTS: In this study, we performed single-unit electrophysiology to identify odorants that are strong activators, inhibitors, and prolonged activators of ACP odorant receptor neurons (ORNs. We identified a suite of odorants that activated the ORNs with high specificity and sensitivity, which may be useful in eliciting behavior such as attraction. In separate experiments, we also identified odorants that evoked prolonged ORN responses and antagonistic odorants able to suppress neuronal responses to activators, both of which can be useful in lowering attraction to hosts. In field trials, we tested the electrophysiologically identified activating odorants and identified a 3-odor blend that enhances trap catches by ∼230%. CONCLUSION: These findings provide a set of odorants that can be used to develop affordable and safe odor-based surveillance and masking strategies for this dangerous pest insect.

  4. Exposure to Guava Affects Citrus Olfactory Cues and Attractiveness to Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Barman, Jagadish Chandra; Campbell, Stuart A; Zeng, Xinnian

    2016-06-01

    Intercropping can reduce agricultural pest incidence, and represents an important sustainable alternative to conventional pest control methods. Understanding the ecological mechanisms for intercropping could help optimize its use, particularly in tropical systems which present a large number of intercropping possibilities. Citrus is threatened worldwide by greening disease (huanglongbing, HLB) vectored by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). Control of HLB and citrus psyllid can be partially achieved through intercropping with guava, Psidium guajava L., but the mechanisms remain unclear. We tested the hypothesis that guava olfactory cues affect psyllid behavior by altering the attractiveness of citrus through plant-plant interactions. In choice and no-choice cage experiments, psyllid settlement was reduced on citrus shoots that had been exposed to guava shoot odors for at least 2 h. In Y-tube olfactometer experiments, psyllids oriented to odors of unexposed, compared with guava-exposed, citrus shoots. These behavioral results indicate that a mechanism for the success of guava intercropping for sustainable, ecological disease management may be the indirect effect of guava on citrus attractiveness.

  5. Species clarification of Isaria isolates used as biocontrol agents against Diaphorina citri (Hemiptera: Liviidae) in Mexico.

    Science.gov (United States)

    Gallou, Adrien; Serna-Domínguez, María G; Berlanga-Padilla, Angélica M; Ayala-Zermeño, Miguel A; Mellín-Rosas, Marco A; Montesinos-Matías, Roberto; Arredondo-Bernal, Hugo C

    2016-03-01

    Entomopathogenic fungi belonging to the genus Isaria (Hypocreales: Cordycipitaceae) are promising candidates for microbial control of insect pests. Currently, the Mexican government is developing a biological control program based on extensive application of Isaria isolates against Diaphorina citri (Hemiptera: Liviidae), a vector of citrus huanglongbing disease. Previous research identified three promising Isaria isolates (CHE-CNRCB 303, 305, and 307; tentatively identified as Isaria fumosorosea) from Mexico. The goal of this work was to obtain a complete morphological and molecular characterization of these isolates. Comparative analysis of morphology established that the isolates showed similar characteristics to Isaria javanica. Multi-gene analysis confirmed the morphological identification by including the three isolates within the I. javanica clade. Additionally, this work demonstrated the misidentifications of three other Isaria isolates (CHE-CNRCB 310 and 324: I. javanica, formerly I. fumosorosea; CHE-CNRCB 393: I. fumosorosea, formerly Isaria farinosa), underlying the need for a full and correct characterization of an isolate before developing a biological control program. Finally, the inter-simple sequence repeat (ISSR) genotyping method revealed that the CHE-CNRCB 303, 305, and 307 isolates belong to three different genotypes. This result indicates that ISSR markers could be used as a tool to monitor their presence in field conditions.

  6. Effective use of neonicotinoids for protection of citrus seedlings from invasion by Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Ichinose, Katsuya; Bang, Doan V; Tuan, Do H; Dien, Le Q

    2010-02-01

    The application of insecticides to control Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a principal component of the current management for citrus greening disease or Huanglongbing. It is recommended that growers apply systemic insecticides such as imidacloprid and thiamethoxam every 2 mo after seedling planting, but this practice renders the seedlings insecticide-free and vulnerable to psyllid infestation in the first 2 mo. We evaluated the risk of vector invasion during this period from field studies of the psyllid in five new king mandarin, Citrus nobilis Loureiro, orchards in the Mekong Delta region of Vietnam. The first psyllids were found after the first 2 wk, and 2 to 60% of the trees were finally infested by psyllids during the 2 mo. The risk of psyllid invasion could be significantly reduced if the insecticide were applied to seedlings before planting. Three systemics, imidacloprid, thiamethoxam, and clothianidin, were examined in both a net house and in the field to assess how quickly they could be effective after application and how long their efficacy could continue. High psyllid mortality >80% was attained in 10 d after application, and this level was maintained for 90 d in the net house and for 60 d in the field. Based on these results, we propose the effective use of neonicotinoids for protection of citrus seedlings against invasive psyllids during the first 2 mo after planting.

  7. Resistance of Citrus and Related Genera to Diaphorina citri Kuwayama (Hemiptera: Liviidae).

    Science.gov (United States)

    Borgoni, P C; Vendramim, J D; Lourencão, A L; Machado, M A

    2014-10-01

    The present study was developed to evaluate the resistance of the following genotypes of Citrus and related genera to this pest: 'Pera,' 'Natal', and 'Washington Navel' oranges (Citrus sinensis), 'Marsh Seedless' grapefruit (Citrus paradisi), hardy orange 'Rubidoux' (Poncirus trifoliata), kumquat (Fortunella margarita Swingle), citrumelo 'Swingle' (C. paradisi x P. trifoliata), and citrange 'Troyer' (P. trifoliata x C. sinensis). The experiments were performed in greenhouses with plants grafted onto 'Rangpur' lime (Citrus limonia) and placed individually in voile cages. The preference for oviposition in a no-choice test, and the effect of genotype were evaluated. The egg-adult cycle was monitored to determine the effect of genotype on the biology of the insect. Poncirus 'Rubidoux' was the least preferred genotype for oviposition; reduced number of eggs was also found to occur on citrange 'Troyer', and 'Marsh Seedless' was the genotype with the most eggs. No significant variation in the duration of the embryonic period was observed; however, a difference in the viability of eggs was found, with the lowest egg viabilities on 'Swingle.' Kumquat and 'Marsh Seedless' genotypes were correlated with increased durations of the nymphal phase, however, there was no difference in the survival of this phase. Fecundity of females on 'Troyer', 'Swingle', and kumquat was reduced. Considering all of the evaluated parameters, it was concluded that cultivars of sweet orange are the most susceptible genotypes to Diaphorina citri. Regarding oviposition, P. trifoliata 'Rubidoux' showed resistance of the antixenosis type.

  8. Partial purification and properties of a cysteine protease from citrus red mite Panonychus citri.

    Science.gov (United States)

    Hong, Seong Chul; Her, Kyu-Hee; Kim, Heung-Up; Lee, Jaechun; Lee, Sang Pyo; Chung, Young-Bae

    2014-02-01

    Several studies have reported that the citrus red mites Panonychus citri were an important allergen of citrus-cultivating farmers in Jeju Island. The aim of the present study was to purify and assess properties of a cysteine protease from the mites acting as a potentially pathogenic factor to citrus-cultivating farmers. A cysteine protease was purified using column chromatography of Mono Q anion exchanger and Superdex 200 HR gel filtration. It was estimated to be 46 kDa by gel filtration column chromatography and consisted of 2 polypeptides, at least. Cysteine protease inhibitors, such as trans poxy-succinyl-L-leucyl-amido (4-guanidino) butane (E-64) and iodoacetic acid (IAA) totally inhibited the enzyme activities, whereas serine or metalloprotease inhibitors did not affect the activities. In addition, the purified enzyme degraded human IgG, collagen, and fibronectin, but not egg albumin. From these results, the cysteine protease of the mites might be involved in the pathogenesis such as tissue destruction and penetration instead of nutrient digestion. PMID:24623894

  9. Caracterização molecular através da técnica fAFLP de isolados de Diaporthe citri Molecular characterization of Diaporthe citri isolates using fAFLP technique

    Directory of Open Access Journals (Sweden)

    Márcia de Holanda Nozaki

    2006-06-01

    Full Text Available A citricultura é um mercado em expansão, principalmente no Estado de São Paulo, cuja importância na balança comercial já é reconhecida. Como em qualquer espécie cultivada, o crescimento das áreas de cultivo favorecem também o crescimento de problemas fitossanitários. Desta forma, as espécies de citros são afetadas por diversas doenças destacando-se entre elas a melanose, causada por Diaporthe citri (Wolf., à qual a grande maioria das variedades comerciais são suscetíveis. O conhecimento da diversidade intra-específica é de grande importância, já que esta poderá auxiliar na seleção de variedades com resistência. O objetivo deste trabalho foi avaliar a variabilidade genética em isolados de Diaporthe citri, originários de diferentes locais, variedades e partes da planta, utilizando marcadores moleculares. Marcadores do tipo AFLP (Amplified Fragment Length Polymorphism foram utilizados para caracterização de dez isolados do patógeno. Os DNAs genômicos extraídos da massa micelial foram utilizados nas reações de amplificação. A técnica fluorescent AFLP permitiu a distinção dos isolados estudados, tendo sido classificados em quatro grupos distintos. Contudo, estes grupos não foram formados em razão da região geográfica, parte da planta ou variedade.Citriculture is a market in expansion specially in Sao Paulo State, whose importance in the economy is already recognized. Like any other cultivated species, the increase of planted areas contributes to an increase in disease problems. Thus, many diseases affect citrus species, including melanose, caused by Diaporthe citri (Wolf., to which most commercial varieties are susceptible to the disease. Knowledge of the intra-specific diversity is important when selecting varieties for resistance. This study evaluated the genetic variability among Diaporthe citri isolates, obtained from different geographical regions, varieties, and parts of the plant using molecular

  10. 60Co-γ Irradiation Affects the Enzymatic Antioxidant System of the Citrus Red Mite Panonychus citri (Acari: Tetranychidae

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    Ke Zhang

    2014-05-01

    Full Text Available Radio-(60Co, which emits γ rays, has been used worldwide in pest control. The aim of the present study was to analyze the effect of effective-low-power 60Co-γ irradiation on the enzymatic antioxidant system of the citrus red mite Panonychus citri. One day old female adults were exposed to 0.4 kGy 60Co-γ irradiation and on the, 6th h, 1st day, 2nd day, and 5th day post treatment, the mites were euthanized for biochemical analysis. The activity of superoxide dismutase (SOD, catalase (CAT, peroxidase (POD, phenoloxidase (PO and acetylocholinesterase (AchE were investigated. POD and CAT activities, as well as SOD were higher in the irradiated mites. We found that exposure to 60Co-γ radiation resulted in increased activities of SOD, CAT, POD and decreased AchE activity. When the recovery time lasted till the 5th day, the activities of POD and PO were significantly lower than the control, whereas the SOD, CAT and AchE activities returned to control levels. Cells possess protein repair pathways to rescue oxidized proteins and restore their functions, but if these repair processes fail, oxidized proteins may become cytotoxic. Our results confirm the hypothesis that low dosages of 60Co-γ irradiation increase the level of oxidative stress in P. citri adults in a short time, causing meanwhile damage and sterility. The results of this study also indicate that stress caused by exposure to irradiation could inhibit the cholinergic system in P. citri.

  11. Purification and partial characterization of glutathione S-transferases from three field populations of Panonychus citri (Acari: Tetranychidae).

    Science.gov (United States)

    Niu, Jin-Zhi; Dou, Wei; Wang, Bao-Jun; Zhang, Guo-Na; Zhang, Rui; Yin, Yi; Wang, Jin-Jun

    2012-02-01

    Glutathione S-transferases (GSTs) play central roles in phase II detoxification of both xenobiotics (drugs, insecticides, and herbicides) and endogenous compounds in almost all living organisms. In this study, we successfully purified the GSTs from the citrus red mite, Panonychus citri, by affinity chromatography on Glutathione Sepharose 4B and compared the biochemical characterizations of the purified GSTs from three field populations [beibei (BB), wanzhou (WZ), and zhongxian (ZX)]. SDS-PAGE revealed that the molecular weight of GSTs from three populations consisted of two subunits of 27.3 and 26.1 kDa. The specific activity of the purified GSTs from the WZ and ZX populations was increased 1.5- and 3.8-fold, respectively, compared with the BB population. Accordingly, the pyridaben susceptibility of WZ and ZX populations was less compared with BB population. Kinetic analyses showed that the WZ and ZX populations had higher substrate specificity compared with the BB population based on the values of k (cat) and k (cat) /K (m) to both reduced glutathione (GSH) and 1-chloro-2,4-dinitrobenzene (CDNB). The in vitro inhibition studies of GSTs indicated that the I (50) values of pyridaben from WZ and ZX populations of P. citri expressed 1.6- and 4.4-fold decreases, respectively, compared to the I (50) value of pyridaben from the BB population. In conclusion, all evidence suggested that the purified GSTs may partially contribute to the susceptibility of acaricide pyridaben in field populations of P. citri. PMID:21979304

  12. (60)Co-γ irradiation affects the enzymatic antioxidant system of the citrus red mite Panonychus citri (Acari: Tetranychidae).

    Science.gov (United States)

    Zhang, Ke; Li, Zhibin; Zhu, Shaowen; Weng, Qunfang

    2014-01-01

    Radio-(60Co), which emits γ rays, has been used worldwide in pest control. The aim of the present study was to analyze the effect of effective-low-power 60Co-γ irradiation on the enzymatic antioxidant system of the citrus red mite Panonychus citri. One day old female adults were exposed to 0.4 kGy 60Co-γ irradiation and on the, 6th h, 1st day, 2nd day, and 5th day post treatment, the mites were euthanized for biochemical analysis. The activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), phenoloxidase (PO) and acetylocholinesterase (AchE) were investigated. POD and CAT activities, as well as SOD were higher in the irradiated mites. We found that exposure to 60Co-γ radiation resulted in increased activities of SOD, CAT, POD and decreased AchE activity. When the recovery time lasted till the 5th day, the activities of POD and PO were significantly lower than the control, whereas the SOD, CAT and AchE activities returned to control levels. Cells possess protein repair pathways to rescue oxidized proteins and restore their functions, but if these repair processes fail, oxidized proteins may become cytotoxic. Our results confirm the hypothesis that low dosages of 60Co-γ irradiation increase the level of oxidative stress in P. citri adults in a short time, causing meanwhile damage and sterility. The results of this study also indicate that stress caused by exposure to irradiation could inhibit the cholinergic system in P. citri. PMID:24853454

  13. Structural-functional characterization and physiological significance of ferredoxin-NADP reductase from Xanthomonas axonopodis pv. citri.

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    María Laura Tondo

    Full Text Available Xanthomonas axonopodis pv. citri is a phytopathogen bacterium that causes severe citrus canker disease. Similar to other phytopathogens, after infection by this bacterium, plants trigger a defense mechanism that produces reactive oxygen species. Ferredoxin-NADP(+ reductases (FNRs are redox flavoenzymes that participate in several metabolic functions, including the response to reactive oxygen species. Xanthomonas axonopodis pv. citri has a gene (fpr that encodes for a FNR (Xac-FNR that belongs to the subclass I bacterial FNRs. The aim of this work was to search for the physiological role of this enzyme and to characterize its structural and functional properties. The functionality of Xac-FNR was tested by cross-complementation of a FNR knockout Escherichia coli strain, which exhibit high susceptibility to agents that produce an abnormal accumulation of (•O(2(-. Xac-FNR was able to substitute for the FNR in E. coli in its antioxidant role. The expression of fpr in X. axonopodis pv. citri was assessed using semiquantitative RT-PCR and Western blot analysis. A 2.2-fold induction was observed in the presence of the superoxide-generating agents methyl viologen and 2,3-dimethoxy-1,4-naphthoquinone. Structural and functional studies showed that Xac-FNR displayed different functional features from other subclass I bacterial FNRs. Our analyses suggest that these differences may be due to the unusual carboxy-terminal region. We propose a further classification of subclass I bacterial FNRs, which is useful to determine the nature of their ferredoxin redox partners. Using sequence analysis, we identified a ferredoxin (XAC1762 as a potential substrate of Xac-FNR. The purified ferredoxin protein displayed the typical broad UV-visible spectrum of [4Fe-4S] clusters and was able to function as substrate of Xac-FNR in the cytochrome c reductase activity. Our results suggest that Xac-FNR is involved in the oxidative stress response of Xanthomonas axonopodis pv

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

    Energy Technology Data Exchange (ETDEWEB)

    Cary; R. Bruce (Santa Fe, NM); Stubben, Christopher J. (Los Alamos, NM)

    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.

  15. Molecular Characterization of Vitellogenin and Its Receptor Genes from Citrus Red Mite, Panonychus citri (McGregor)

    OpenAIRE

    Rui Zhong; Tian-Bo Ding; Jin-Zhi Niu; Wen-Kai Xia; Chong-Yu Liao; Wei Dou; Jin-Jun Wang

    2015-01-01

    The production and uptake of yolk protein play an important role in the reproduction of all oviparous organisms. Vitellogenin (Vg) is the precursor of vitellin (Vn), which is the major egg storage protein, and vitellogenin receptor (VgR) is a necessary protein for the uptake of Vg into developing oocytes. In this paper, we characterize the full-length Vg and VgR, PcVg1 and PcVgR, respectively, of the citrus red mite Panonychus citri (McGregor). The PcVg1 cDNA is 5748 nucleotides (nt) with a ...

  16. 60Co-γ Irradiation Affects the Enzymatic Antioxidant System of the Citrus Red Mite Panonychus citri (Acari: Tetranychidae)

    OpenAIRE

    Ke Zhang; Zhibin Li; Shaowen Zhu; Qunfang Weng

    2014-01-01

    Radio-(60Co), which emits γ rays, has been used worldwide in pest control. The aim of the present study was to analyze the effect of effective-low-power 60Co-γ irradiation on the enzymatic antioxidant system of the citrus red mite Panonychus citri. One day old female adults were exposed to 0.4 kGy 60Co-γ irradiation and on the, 6th h, 1st day, 2nd day, and 5th day post treatment, the mites were euthanized for biochemical analysis. The activity of superoxide dismutase (SOD), catalase (CAT), p...

  17. Sobre o condicionamento alimentar na cochonilha-branca, Planococcus citri (Risso (Hemiptera: pseudococcidae

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    Lenira Viana Costa Santa-Cecília

    2013-03-01

    Full Text Available Estudos do comportamento alimentar mediante a técnica de "Electrical Penetration Graphs" (EPG das cochonilhas-farinhentas (Pseudococcidae provenientes de um hospedeiro de criação alternativo têm mostrado que esses insetos não atingem ou demoram cerca de 9 horas para alcançar a fase floemática. Por outro lado, aqueles provenientes do hospedeiro-fonte atingem a fase floemática mais rapidamente e apresentam maior frequência de alimentação nos vasos crivados. Esses resultados indicam a presença do fenômeno de condicionamento alimentar, ainda não demonstrado em cochonilhas. Assim, o presente trabalho teve como objetivo determinar a existência desse fenômeno em Planococcus citri (Risso (Hemiptera: Pseudococcidae. Foram realizados testes de livre escolha, monitoramento eletrônico (EPG e estudos de alguns parâmetros biológicos. Em todos os experimentos, o cafeeiro (Coffea arabica L., os citros (Citrus sinensis L. e abóbora (Cucurbita maxima L. foram utilizados como substratos de criação (fonte da cochonilha, sendo os tratamentos constituídos pela combinação entre os hospedeiros-fonte e os hospedeiros receptores (café e citros. O teste de escolha entre cafeeiro e citros nas primeiras 72 horas mostrou que as cochonilhas criadas em cafeeiro apresentaram preferência pelo cafeeiro; aquelas originadas dos citros mostraram uma tendência, embora não significativa, em selecionar os citros em relação ao cafeeiro e aquelas criadas em abóbora não mostraram preferência por nenhum dos hospedeiros. Os estudos do comportamento alimentar mediante o monitoramento eletrônico (EPG mostraram que a fase floemática, considerada como a fase de aceitação do hospedeiro, foi mais frequente em cafeeiro, seja com cochonilhas oriundas deste substrato, seja de citros. Aqueles insetos mantidos em abóbora e transferidos para o cafeeiro ou citros apresentaram excepcionalmente ou não apresentaram nenhuma fase floemática, respectivamente. A

  18. Use of the entomopathogenic fungi Metarhizium anisopliae, Cordyceps bassiana and Isaria fumosorosea to control Diaphorina citri (Hemiptera: Psylidae) in Persian lime under field conditions

    Science.gov (United States)

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a destructive insect pest in the citriculture, because it is an efficient vector of the proteobacteria, ‘Candidatus Liberibacter asiaticus’ (Las), ‘Ca. L. Africanus’ (Laf), and ‘Ca. L. Americanus’ (Lam). These bacteria c...

  19. Host range testing of Tamarixia radiata (Hymenoptera: Eulophidae) sourced from the Punjab of Pakistan for classical biological control of Diaphorina citri (Hemiptera: Liviidae: Euphyllurinae: Diaphorinini) in California.

    Science.gov (United States)

    Hoddle, Mark S; Pandey, Raju

    2014-02-01

    ABSTRACT Tests evaluating the host range of Tamarixia radiata (Waterson) (Hymenoptera: Eulophidae), a parasitoid of the pestiferous Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), sourced from the Punjab of Pakistan, were conducted in quarantine at the University of California, Riverside, CA. Seven nontarget psyllid species (five native and two self-introduced species) representing five families were exposed to T radiata under the following three different exposure scenarios: 1) sequential no-choice tests, 2) static no-choice tests, and 3) choice tests. Nontarget species were selected for testing based on the following criteria: 1) taxonomic relatedness to the target, D. citri; 2) native psyllids inhabiting native host plants related to citrus that could release volatiles attractive to T. radiata; 3) native psyllids with a high probability of occurrence in native vegetation surrounding commercial citrus groves that could be encountered by T. radiata emigrating from D. citri-infested citrus orchards; 4) a common native pest psyllid species; and 5) a beneficial psyllid attacking a noxious weed. The results of host range testing were unambiguous; T radiata exhibited a narrow host range and high host specificity, with just one species of nontarget psyllid, the abundant native pest Bactericera cockerelli Sulc, being parasitized at low levels (citri poses negligible environmental risk. PMID:24665694

  20. Natural parasitism of Diaphorina citri Kuwayama (Hemiptera, Psyllidae nymphs by Tamarixia radiata Waterston (Hymenoptera, Eulophidae in São Paulo orange groves

    Directory of Open Access Journals (Sweden)

    Paulo Eduardo Branco Paiva

    2012-12-01

    Full Text Available The psyllid Diaphorina citri Kuwayama 1908 has become the main citrus pest species in the state of São Paulo, Brazil, after the introduction of the huanglongbing or citrus greening. This study evaluated the parasitism of 3rd, 4th and 5th instar D. citri nymphs by Tamarixia radiata (Waterston, 1922 in citrus groves under a regimen of regular insecticide applications in ten producing regions: Araraquara, Barretos, Bauru, Botucatu, Franca, Itapetininga, Jaú, Limeira, Lins and São João da Boa Vista. Sixty-nine samples of new branches infested with nymphs of D. citri were collected from 2005 to 2008 in orange groves ranging from 1 to 20 years old, of the varieties Hamlin, Pera, Valencia and Natal. The parasitoid T. radiata is widely distributed in São Paulo orange groves, and was identified in 50 (72% of the samples, showing a mean parasitism rate of 12.4%. The highest parasitism rate was observed in the "summer" (from January through March, with a mean of 25.7%. Nymphal parasitism was above 90% in two samples. The probable causes of the variations in parasitism of D. citri by T. radiata are discussed.

  1. Research Progress in Control Technology of Diaphorina citri%柑橘木虱的防治技术研究进展

    Institute of Scientific and Technical Information of China (English)

    杜丹超; 鹿连明; 张利平; 胡秀荣; 黄振东; 陈国庆

    2011-01-01

    Control of Diaphorina citri is the key component of integrated control for citrus huanglongbing. This review summarized control technology of Diaphorina citri, including field management, chemical control, and biological control and so on. Furthermore, the development trend of control of Diaphorina citri was discussed. This paper was aimed to provide theoretical references and technical supports for prevention and control of Diaphorina citri and citrus huanglongbing.%防治柑橘木虱是柑橘黄龙病综合防控的关键措施.主要阐述了柑橘木虱的防治技术手段,包括田间管理、化学防治、生物防治等,并且探讨了柑橘木虱防治的发展趋势,旨在为防治柑橘木虱及防控柑橘黄龙病提供理论参考和技术支撑.

  2. Host range testing of Tamarixia radiata (Hymenoptera: Eulophidae) sourced from the Punjab of Pakistan for classical biological control of Diaphorina citri (Hemiptera: Liviidae: Euphyllurinae: Diaphorinini) in California.

    Science.gov (United States)

    Hoddle, Mark S; Pandey, Raju

    2014-02-01

    ABSTRACT Tests evaluating the host range of Tamarixia radiata (Waterson) (Hymenoptera: Eulophidae), a parasitoid of the pestiferous Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), sourced from the Punjab of Pakistan, were conducted in quarantine at the University of California, Riverside, CA. Seven nontarget psyllid species (five native and two self-introduced species) representing five families were exposed to T radiata under the following three different exposure scenarios: 1) sequential no-choice tests, 2) static no-choice tests, and 3) choice tests. Nontarget species were selected for testing based on the following criteria: 1) taxonomic relatedness to the target, D. citri; 2) native psyllids inhabiting native host plants related to citrus that could release volatiles attractive to T. radiata; 3) native psyllids with a high probability of occurrence in native vegetation surrounding commercial citrus groves that could be encountered by T. radiata emigrating from D. citri-infested citrus orchards; 4) a common native pest psyllid species; and 5) a beneficial psyllid attacking a noxious weed. The results of host range testing were unambiguous; T radiata exhibited a narrow host range and high host specificity, with just one species of nontarget psyllid, the abundant native pest Bactericera cockerelli Sulc, being parasitized at low levels (citri poses negligible environmental risk.

  3. Characterization of a recombinant Cathepsin B-Like cysteine peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae): A putative target control of citrus huanglongbing

    Science.gov (United States)

    Huanglongbing (HLB) is one of the most destructive disease affecting citrus plants. The causal agent is associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas) spread by the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae). Among the control strategies for H...

  4. Differential expression of pathogenicity- and virulence-related genes of Xanthomonas axonopodis pv. citri under copper stress

    Directory of Open Access Journals (Sweden)

    Ana Carolina Basílio Palmieri

    2010-01-01

    Full Text Available In this study, we used real-time quantitative PCR (RT-qPCR to evaluate the expression of 32 genes of Xanthomonas axonopodis pv. citri related to pathogenicity and virulence that are also involved in copper detoxification. Nearly all of the genes were up-regulated, including copA and copB. Two genes homologous to members of the type II secretion system (xcsH and xcsC and two involved in the degradation of plant cell wall components (pglA and pel were the most expressed in response to an elevated copper concentration. The type II secretion system (xcs operon and a few homologues of proteins putatively secreted by this system showed enhanced expression when the bacteria were exposed to a high concentration of copper sulfate. The enhanced expression of the genes of secretion II system during copper stress suggests that this pathway may have an important role in the adaptative response of X. axonopodis pv. citri to toxic compounds. These findings highlight the potential role of these genes in attenuating the toxicity of certain metals and could represent an important means of bacterial resistance against chemicals used to control diseases.

  5. Lethal and Sublethal Impacts of Acaricides on Tamarixia radiata (Hemiptera: Eulophidae), an Important Ectoparasitoid of Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Lira, A C S; Zanardi, O Z; Beloti, V H; Bordini, G P; Yamamoto, P T; Parra, J R P; Carvalho, G A

    2015-10-01

    The use of synthetic acaricides for management of pest mites may alter the efficacy of the ectoparasitoid Tamarixia radiata (Waterston) in biological control of Diaphorina citri Kuwayama, the vector of the bacteria associated with huanglongbing (HLB) in citrus orchards. We evaluated the toxicity of 16 acaricides that are recommended for the control of citrus-pest mites to T. radiata. Acrinathrin, bifenthrin, carbosulfan, and fenpropathrin caused high acute toxicity and were considered harmful (mortality >77%) to T. radiata. Abamectin, diflubenzuron, etoxazole, fenbutatin oxide, fenpyroximate, flufenoxuron, hexythiazox, propargite, spirodiclofen, and sulfur caused low acute toxicity and affected the parasitism rate and emergence rate of adults (F1 generation), and were considered slightly harmful to T. radiata. Dicofol and pyridaben did not affect the survival and action of the ectoparasitoid, and were considered harmless. In addition to its acute toxicity, carbosulfan caused mortality higher than 25% for >30 d after application, and was considered persistent. Acrinathrin, bifenthrin, fenpropathrin, fenpyroximate, propargite, and sulfur caused mortalities over 25% until 24 d after application and were considered moderately persistent; abamectin was slightly persistent, and fenbutatin oxide was short lived. Our results suggest that most acaricides used to control pest mites in citrus affect the density and efficacy of T. radiata in the biological control of D. citri. However, further evaluations are needed in order to determine the effect of these products on this ectoparasitoid under field conditions. PMID:26453716

  6. Crystallization, data collection and phasing of the molybdate-binding protein of the phytopathogen Xanthomonas axonopodis pv. citri

    Energy Technology Data Exchange (ETDEWEB)

    Santacruz, C. P.; Balan, A.; Ferreira, L. C. S. [Departamento de Microbiologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo, SP (Brazil); Barbosa, J. A. R. G., E-mail: joao@lnls.br [Centro de Biologia Molecular e Estrutural (CeBiMe), Laboratório Nacional de Luz Síncrotron (LNLS), CP 6192, Campinas, SP 13084-971 (Brazil); Departamento de Microbiologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo, SP (Brazil)

    2006-03-01

    The molybdate-binding protein (ModA) from X. axonopodis pv. citri was crystallized with sodium molybdate in the presence of PEG or sulfate. The crystal diffracted to a maximum resolution of 1.7 Å and belongs to the orthorhombic space group C222{sub 1,} with unit-cell parameters a = 68.15, b = 172.14, c = 112.04 Å. Xanthomonas axonopodis pv. citri ModA protein is the ABC periplasmic binding component responsible for the capture of molybdate. The protein was crystallized with sodium molybdate using the hanging-drop vapour-diffusion method in the presence of PEG or sulfate. X-ray diffraction data were collected to a maximum resolution of 1.7 Å using synchrotron radiation. The crystal belongs to the orthorhombic space group C222{sub 1}, with unit-cell parameters a = 68.15, b = 172.14, c = 112.04 Å. The crystal structure was solved by molecular-replacement methods and structure refinement is in progress.

  7. Lethal and Sublethal Impacts of Acaricides on Tamarixia radiata (Hemiptera: Eulophidae), an Important Ectoparasitoid of Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Lira, A C S; Zanardi, O Z; Beloti, V H; Bordini, G P; Yamamoto, P T; Parra, J R P; Carvalho, G A

    2015-10-01

    The use of synthetic acaricides for management of pest mites may alter the efficacy of the ectoparasitoid Tamarixia radiata (Waterston) in biological control of Diaphorina citri Kuwayama, the vector of the bacteria associated with huanglongbing (HLB) in citrus orchards. We evaluated the toxicity of 16 acaricides that are recommended for the control of citrus-pest mites to T. radiata. Acrinathrin, bifenthrin, carbosulfan, and fenpropathrin caused high acute toxicity and were considered harmful (mortality >77%) to T. radiata. Abamectin, diflubenzuron, etoxazole, fenbutatin oxide, fenpyroximate, flufenoxuron, hexythiazox, propargite, spirodiclofen, and sulfur caused low acute toxicity and affected the parasitism rate and emergence rate of adults (F1 generation), and were considered slightly harmful to T. radiata. Dicofol and pyridaben did not affect the survival and action of the ectoparasitoid, and were considered harmless. In addition to its acute toxicity, carbosulfan caused mortality higher than 25% for >30 d after application, and was considered persistent. Acrinathrin, bifenthrin, fenpropathrin, fenpyroximate, propargite, and sulfur caused mortalities over 25% until 24 d after application and were considered moderately persistent; abamectin was slightly persistent, and fenbutatin oxide was short lived. Our results suggest that most acaricides used to control pest mites in citrus affect the density and efficacy of T. radiata in the biological control of D. citri. However, further evaluations are needed in order to determine the effect of these products on this ectoparasitoid under field conditions.

  8. Acaricidal activity against Panonychus citri of a ginkgolic acid from the external seed coat of Ginkgo biloba.

    Science.gov (United States)

    Pan, Weigao; Luo, Peng; Fu, Ruobin; Gao, Ping; Long, Zhangfu; Xu, Feiyi; Xiao, Haibo; Liu, Shigui

    2006-03-01

    An acaricidal substance extracted from the external seed coat of Ginkgo biloba L. was identified by UV (ultraviolet), IR (infrared), EI-MS (electron impact ion source mass spectrometry), (1)H NMR (nuclear magnetic resonance) and (13)C NMR as 6-[(Z)-10-heptadecenyl]-2-hydroxybenzoic acid (compound 1). Laboratory bioassay on citrus red mite, Panonychus citri (Mcg), showed that compound 1 possessed the following properties. (i) Powerful contact toxicity with an LC(50) of 5.2 mg litre(-1) after 24 h that was similar to that of pyridaben (LC(50) = 3.4 mg litre(-1)) and significantly superior to that of omethoate (LC(50) = 122 mg litre(-1)). Furthermore, its LC(90) was 13.4 mg litre(-1) after 24 h, which is significantly superior to both pyridaben (LC(90) = 69.6 mg litre(-1)) and omethoate (LC(90) = 453 mg litre(-1)). (ii) Quick-acting acaricidal activity. At identical concentrations, compound 1 was much faster-acting than pyridaben or omethoate. (iii) Compound 1 had strong corrosive action on the cuticle of P. citri but no phytotoxicity to plants. PMID:16475219

  9. Characterization of a Recombinant Cathepsin B-Like Cysteine Peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae: A Putative Target for Control of Citrus Huanglongbing.

    Directory of Open Access Journals (Sweden)

    Taíse Fernanda da Silva Ferrara

    Full Text Available Huanglonbing (HLB is one of the most destructive disease affecting citrus plants. The causal agent is associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas and the psyllid Diaphorina citri, vector of disease, that transmits the bacterium associated with HLB. The control of disease can be achieved by suppressing either the bacterium or the vector. Among the control strategies for HLB disease, one of the widely used consists in controlling the enzymes of the disease vector, Diaphorina citri. The insect Diaphorina citri belongs to the order Hemiptera, which frequently have cysteine peptidases in the gut. The importance of this class of enzymes led us to search for enzymes in the D. citri transcriptome for the establishment of alternatives strategies for HLB control. In this study, we reported the identification and characterization of a cathepsin B-like cysteine peptidase from D. citri (DCcathB. DCcathB was recombinantly expressed in Pichia pastoris, presenting a molecular mass of approximately 50 kDa. The enzyme hydrolyzed the fluorogenic substrate Z-F-R-AMC (Km = 23.5 μM and the selective substrate for cathepsin B, Z-R-R-AMC (Km = 6.13 μM. The recombinant enzyme was inhibited by the cysteine protease inhibitors E64 (IC50 = 0.014 μM and CaneCPI-4 (Ki = 0.05 nM and by the selective cathepsin B inhibitor CA-074 (IC50 = 0.095 nM. RT-qPCR analysis revealed that the expression of the DCcathB in nymph and adult was approximately 9-fold greater than in egg. Moreover, the expression of this enzyme in the gut was 175-fold and 3333-fold higher than in the remaining tissues and in the head, respectively, suggesting that DCcathB can be a target for HLB control.

  10. Effect of UV-Blocking Plastic Films on Take-Off and Host Plant Finding Ability of Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Miranda, M P; Dos Santos, F L; Felippe, M R; Moreno, A; Fereres, A

    2015-02-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a major pest of citrus worldwide due to its ability to transmit the bacteria associated with huanglongbing. Vision, behavior, and performance of insect pests can be manipulated by using ultraviolet (UV)-blocking materials. Thus, the aim of our study was to evaluate how UV-blocking plastic films may affect the take-off and host plant finding ability of D. citri. To assess the effect of a UV-deficient environment on take-off, adult psyllids were released from a vial inside a screenhouse covered by a UV-blocking or standard (control) film and the number of insects remaining on each vial under each treatment was counted at different time intervals. Moreover, to assess the ability of D. citri to find citrus plants under a UV-deficient environment, two independent no-choice host plant finding assays with different plant arrangements were conducted. In each treatment, the number of psyllids per plant at different time intervals was counted. Both D. citri take-off and host plant finding ability was clearly disrupted under a UV-deficient environment. The number of psyllids remaining in the vials was significantly higher under UV-blocking than standard film in all periods recorded. Furthermore, psyllids were present in significantly higher number on citrus plants under standard film than under UV-blocking film in all of the periods assessed and experiments conducted. Our results showed that UV-blocking materials could become a valuable strategy for integrated management of D. citri and huanglongbing in citrus grown in enclosed environments. PMID:26470126

  11. Characterization of a Recombinant Cathepsin B-Like Cysteine Peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae): A Putative Target for Control of Citrus Huanglongbing.

    Science.gov (United States)

    Ferrara, Taíse Fernanda da Silva; Schneider, Vanessa Karine; Kishi, Luciano Takeshi; Carmona, Adriana Karaoglanovic; Alves, Marcio Fernando Madureira; Belasque-Júnior, Jose; Rosa, José César; Hunter, Wayne Brian; Henrique-Silva, Flávio; Soares-Costa, Andrea

    2015-01-01

    Huanglonbing (HLB) is one of the most destructive disease affecting citrus plants. The causal agent is associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas) and the psyllid Diaphorina citri, vector of disease, that transmits the bacterium associated with HLB. The control of disease can be achieved by suppressing either the bacterium or the vector. Among the control strategies for HLB disease, one of the widely used consists in controlling the enzymes of the disease vector, Diaphorina citri. The insect Diaphorina citri belongs to the order Hemiptera, which frequently have cysteine peptidases in the gut. The importance of this class of enzymes led us to search for enzymes in the D. citri transcriptome for the establishment of alternatives strategies for HLB control. In this study, we reported the identification and characterization of a cathepsin B-like cysteine peptidase from D. citri (DCcathB). DCcathB was recombinantly expressed in Pichia pastoris, presenting a molecular mass of approximately 50 kDa. The enzyme hydrolyzed the fluorogenic substrate Z-F-R-AMC (Km = 23.5 μM) and the selective substrate for cathepsin B, Z-R-R-AMC (Km = 6.13 μM). The recombinant enzyme was inhibited by the cysteine protease inhibitors E64 (IC50 = 0.014 μM) and CaneCPI-4 (Ki = 0.05 nM) and by the selective cathepsin B inhibitor CA-074 (IC50 = 0.095 nM). RT-qPCR analysis revealed that the expression of the DCcathB in nymph and adult was approximately 9-fold greater than in egg. Moreover, the expression of this enzyme in the gut was 175-fold and 3333-fold higher than in the remaining tissues and in the head, respectively, suggesting that DCcathB can be a target for HLB control. PMID:26717484

  12. Morphological characterization of the antennal sensilla of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), with reference to their probable functions.

    Science.gov (United States)

    Onagbola, Ebenezer O; Meyer, Wendy L; Boina, Dhana Raj; Stelinski, Lukasz L

    2008-12-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is one of the most significant economic pests of citrus worldwide. This insect vectors three phloem-restricted bacteria in the genus Candidatus Liberibacter that cause huanglongbing (citrus greening), the most severe disease limiting citrus production worldwide. We examined the external morphology of the antennal sensilla of male and female D. citri using scanning electron microscopy (SEM) and determined the putative functions of the identified sensilla using transmission electron microscopic (TEM) techniques. The filiform antennae of D. citri were of the conventional type comprised of a basal scape, pedicel and a long, thread-like flagellum, which is composed of eight flagellomeres. Eleven morphologically unique sensillar types were found and described on the antennae of male and female D. citri. Of those identified, the two apical setae, multiporous types I and II sensilla trichoidea, and the antennal rhinaria were porous and may be involved in perception of host- and mate-related volatile chemicals. However, the aporous types I, II and III sensilla trichoidea may have mechanosensory functions and the chaetica sensilla, cavity sensilla and unidentified uniporous sensilla may be involved in proprioception, thermo-hygroreception and cold detection, respectively. The shape, external morphology and array of sensilla on the antennae of male and female D. citri were similar. The only major difference observed was in the morphology of the short apical setae, whose tips were recessed inward in females but not so in males. The results are discussed in relation to plausible roles of the identified sensilla in mate and host location by this species.

  13. Effect of UV-Blocking Plastic Films on Take-Off and Host Plant Finding Ability of Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Miranda, M P; Dos Santos, F L; Felippe, M R; Moreno, A; Fereres, A

    2015-02-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a major pest of citrus worldwide due to its ability to transmit the bacteria associated with huanglongbing. Vision, behavior, and performance of insect pests can be manipulated by using ultraviolet (UV)-blocking materials. Thus, the aim of our study was to evaluate how UV-blocking plastic films may affect the take-off and host plant finding ability of D. citri. To assess the effect of a UV-deficient environment on take-off, adult psyllids were released from a vial inside a screenhouse covered by a UV-blocking or standard (control) film and the number of insects remaining on each vial under each treatment was counted at different time intervals. Moreover, to assess the ability of D. citri to find citrus plants under a UV-deficient environment, two independent no-choice host plant finding assays with different plant arrangements were conducted. In each treatment, the number of psyllids per plant at different time intervals was counted. Both D. citri take-off and host plant finding ability was clearly disrupted under a UV-deficient environment. The number of psyllids remaining in the vials was significantly higher under UV-blocking than standard film in all periods recorded. Furthermore, psyllids were present in significantly higher number on citrus plants under standard film than under UV-blocking film in all of the periods assessed and experiments conducted. Our results showed that UV-blocking materials could become a valuable strategy for integrated management of D. citri and huanglongbing in citrus grown in enclosed environments.

  14. Characterization of a Recombinant Cathepsin B-Like Cysteine Peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae): A Putative Target for Control of Citrus Huanglongbing.

    Science.gov (United States)

    Ferrara, Taíse Fernanda da Silva; Schneider, Vanessa Karine; Kishi, Luciano Takeshi; Carmona, Adriana Karaoglanovic; Alves, Marcio Fernando Madureira; Belasque-Júnior, Jose; Rosa, José César; Hunter, Wayne Brian; Henrique-Silva, Flávio; Soares-Costa, Andrea

    2015-01-01

    Huanglonbing (HLB) is one of the most destructive disease affecting citrus plants. The causal agent is associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas) and the psyllid Diaphorina citri, vector of disease, that transmits the bacterium associated with HLB. The control of disease can be achieved by suppressing either the bacterium or the vector. Among the control strategies for HLB disease, one of the widely used consists in controlling the enzymes of the disease vector, Diaphorina citri. The insect Diaphorina citri belongs to the order Hemiptera, which frequently have cysteine peptidases in the gut. The importance of this class of enzymes led us to search for enzymes in the D. citri transcriptome for the establishment of alternatives strategies for HLB control. In this study, we reported the identification and characterization of a cathepsin B-like cysteine peptidase from D. citri (DCcathB). DCcathB was recombinantly expressed in Pichia pastoris, presenting a molecular mass of approximately 50 kDa. The enzyme hydrolyzed the fluorogenic substrate Z-F-R-AMC (Km = 23.5 μM) and the selective substrate for cathepsin B, Z-R-R-AMC (Km = 6.13 μM). The recombinant enzyme was inhibited by the cysteine protease inhibitors E64 (IC50 = 0.014 μM) and CaneCPI-4 (Ki = 0.05 nM) and by the selective cathepsin B inhibitor CA-074 (IC50 = 0.095 nM). RT-qPCR analysis revealed that the expression of the DCcathB in nymph and adult was approximately 9-fold greater than in egg. Moreover, the expression of this enzyme in the gut was 175-fold and 3333-fold higher than in the remaining tissues and in the head, respectively, suggesting that DCcathB can be a target for HLB control.

  15. Foraging on and consumption of two species of papaya pest mites, Tetranychus kanzawai and Panonychus citri (Acari: Tetranychidae), by Mallada basalis (Neuroptera: Chrysopidae).

    Science.gov (United States)

    Cheng, Ling Lan; Nechols, James R; Margolies, David C; Campbell, James F; Yang, Ping Shih; Chen, Chien Chung; Lu, Chiu Tung

    2009-06-01

    Tetranychus kanzawai Kishida and Panonychus citri (McGregor) are two major acarine pests of the principal papaya variety in Taiwan, and they often co-occur in the same papaya screenhouses. This study measured prey acceptability, foraging schedule, short-term consumption rate, and handling time of larvae of a domesticated line of the green lacewing, Mallada basalis (Walker), in no-choice tests with different life stages of these two mite pests. After a period of prey deprivation, all three larval instars of M. basalis exhibited a high rate of acceptance of all life stages of both T. kanzawai and P. citri. In 2-h trials, second- and third-instar predators foraged actively most of the time, whereas first instars spent approximately 40% of the time at rest. Consumption increased and prey handling time decreased as predator life stage advanced and prey stage decreased. Third-instar lacewings consumed an average of 311.4 T. kanzawai eggs (handling time: 6.7 s/egg) and 68.2 adults (handling time: 58.8 s/adult), whereas first instars consumed 19.6 eggs (handling time: 23.6 s/egg) and 4.0 adults (handling time: 633.4 s/adult). M. basalis generally consumed more P. citri than T. kanzawai. Except for prey eggs, handling times of T. kanzawai were generally longer than those of P. citri by all M. basalis instars. Handling times were shorter, and consumption were greater, at the higher P. citri density than at the lower one, whereas there were generally no significant differences in prey acceptability and foraging time between those two densities. This study suggests that M. basalis larvae may have high potential for augmentative biological control of mites on papayas. PMID:19508780

  16. Ultrastructure of the salivary glands and bacteria-like structures in the gut and other organs of the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae), vector of huanglongbing disease bacteria

    Science.gov (United States)

    The Asian citrus psyllid (ACP, Diaphorina citri, Hemiptera, Liviidae) is the principal vector of Candidatus Liberibacter asiaticus (Las), the bacterium associated with huanglongbing (HLB) or citrus greening, currently the most serious citrus disease worldwide. Liberibacter asiaticus is transmitted i...

  17. Natural parasitism of Diaphorina citri Kuwayama (Hemiptera, Psyllidae nymphs by Tamarixia radiata Waterston (Hymenoptera, Eulophidae in São Paulo orange groves Parasitismo natural de ninfas de Diaphorina citri Kuwayama (Hemiptera, Psyllidae por Tamarixia radiata Waterston (Hymenoptera, Eulophidae em pomares de laranja em São Paulo

    Directory of Open Access Journals (Sweden)

    Paulo Eduardo Branco Paiva

    2012-12-01

    Full Text Available The psyllid Diaphorina citri Kuwayama 1908 has become the main citrus pest species in the state of São Paulo, Brazil, after the introduction of the huanglongbing or citrus greening. This study evaluated the parasitism of 3rd, 4th and 5th instar D. citri nymphs by Tamarixia radiata (Waterston, 1922 in citrus groves under a regimen of regular insecticide applications in ten producing regions: Araraquara, Barretos, Bauru, Botucatu, Franca, Itapetininga, Jaú, Limeira, Lins and São João da Boa Vista. Sixty-nine samples of new branches infested with nymphs of D. citri were collected from 2005 to 2008 in orange groves ranging from 1 to 20 years old, of the varieties Hamlin, Pera, Valencia and Natal. The parasitoid T. radiata is widely distributed in São Paulo orange groves, and was identified in 50 (72% of the samples, showing a mean parasitism rate of 12.4%. The highest parasitism rate was observed in the "summer" (from January through March, with a mean of 25.7%. Nymphal parasitism was above 90% in two samples. The probable causes of the variations in parasitism of D. citri by T. radiata are discussed.O psilídeo Diaphorina citri Kuwayama 1908 tornou-se a principal praga dos citros no estado de São Paulo após a introdução do huanglongbing ou grenning dos citros. Este estudo avaliou as proporções de ninfas de terceiro a quinto ínstares de D. citri parasitadas por Tamarixia radiata (Waterston, 1922 em pomares de laranja submetidos a pulverizações constantes de inseticidas em dez regiões produtoras, Araraquara, Barretos, Bauru, Botucatu, Franca, Itapetininga, Jaú, Limeira, Lins e São João da Boa Vista. Foram coletadas 69 amostras de ramos jovens infestados com ninfas de D. citri obtidas entre 2005 e 2008 em pomares de 1 a 20 anos de idade, das cultivares Hamilin, Pera, Valencia e Natal. O parasitóide T. radiata encontra-se amplamente distribuído em pomares de São Paulo, tendo sido observado em 50 amostras (72%, com taxa média de

  18. The complete mitochondrial genome of the citrus red mite Panonychus citri (Acari: Tetranychidae: high genome rearrangement and extremely truncated tRNAs

    Directory of Open Access Journals (Sweden)

    Dou Wei

    2010-10-01

    Full Text Available Abstract Background The family Tetranychidae (Chelicerata: Acari includes ~1200 species, many of which are of agronomic importance. To date, mitochondrial genomes of only two Tetranychidae species have been sequenced, and it has been found that these two mitochondrial genomes are characterized by many unusual features in genome organization and structure such as gene order and nucleotide frequency. The scarcity of available sequence data has greatly impeded evolutionary studies in Acari (mites and ticks. Information on Tetranychidae mitochondrial genomes is quite important for phylogenetic evaluation and population genetics, as well as the molecular evolution of functional genes such as acaricide-resistance genes. In this study, we sequenced the complete mitochondrial genome of Panonychus citri (Family Tetranychidae, a worldwide citrus pest, and provide a comparison to other Acari. Results The mitochondrial genome of P. citri is a typical circular molecule of 13,077 bp, and contains the complete set of 37 genes that are usually found in metazoans. This is the smallest mitochondrial genome within all sequenced Acari and other Chelicerata, primarily due to the significant size reduction of protein coding genes (PCGs, a large rRNA gene, and the A + T-rich region. The mitochondrial gene order for P. citri is the same as those for P. ulmi and Tetranychus urticae, but distinctly different from other Acari by a series of gene translocations and/or inversions. The majority of the P. citri mitochondrial genome has a high A + T content (85.28%, which is also reflected by AT-rich codons being used more frequently, but exhibits a positive GC-skew (0.03. The Acari mitochondrial nad1 exhibits a faster amino acid substitution rate than other genes, and the variation of nucleotide substitution patterns of PCGs is significantly correlated with the G + C content. Most tRNA genes of P. citri are extremely truncated and atypical (44-65, 54.1 ± 4.1 bp, lacking

  19. 柑橘木虱Diaphorina citri Kuwayama内生菌DNA不同提取方法的比较分析%Comparative evaluation on different methods to extract endophytic bacteria DNA from Diaphorina citri Kuwayama

    Institute of Scientific and Technical Information of China (English)

    杨金霞; 阮传清; 刘波; 陈建利

    2013-01-01

    To find a better method for the extraction of endophytic bacteria DNA from Asian Citrus Psyllid,Diaphorina citri Kuwayama,we compared the traditional methods and FastDNA Kits.The result showed that the DNA template extracted with the method of FastDNA Kits (MP Biomedical) was more suitable for PCR amplification,and the amplification product could be well used for cloning and sequencing.In the contrast,although the other three methods were cheaper,the amount and purity of DNA extracted with them were decreased.Our results suggested that the extraction with the FastDNA kits was stable and convenient for operation and standardization but expensiveness.In summary,four methods had respective advantages and disadvantages,and FastDNA kits provided more stable DNA for PCR and sequence cloning.%通过分析细菌16S rDNA基因序列的PCR扩增与克隆测序结果,比较传统方法和试剂盒法对柑橘木虱Diaphorina citri Kuwayama内生菌DNA模板的提取效果.试验表明,4种方法中,FastDNA试剂盒方法提取的DNA模板较适合于后续柑橘木虱内生菌16S rDNA的扩增,且扩增产物可以很好地用于克隆测序;传统提取方法经济节约,但提取的DNA量及纯度较低;试剂盒提取方法,操作简单,质量稳定,易标准化,但成本较高.4种方法各具优缺点,用FastDNA试剂盒提取的DNA模板,其PCR产物能满足克隆需要.

  20. Effect of gamma radiation on some biological aspects of the moth prays Citri mill.(Hyponomeutidae, Lepidoptera)

    International Nuclear Information System (INIS)

    The present work deals with the effect 4 doses of gamma radiation (100, 200, 300 and 400 Gy) on 3 pupal ages of prays citri moth (1, 3 and 5 days before adult emergence) on the adult fecundity, fertility, different oviposition periods and adult longevity. Adult fecundity significantly decreased in the earlier pupal ages at different doses and different combinations (Nx I , I x N and I x I). Also, the decrease in adult fertility was significant in the same pupal ages and at different doses and combinations. The differences between the combination I x N and I x I were insignificant while they were significant when comparing each of them with the other combination (N X I ). Pre-oviposition, oviposition and postoviposition periods were affected significantly when the earlier pupal ages were treated with different gamma doses. Adult longevity was also affected significantly when the pupal at different ages were treated with different gamma doses. 2 tabs

  1. Research Advances in Control of Panonychus citri%柑桔红蜘蛛防控研究进展

    Institute of Scientific and Technical Information of China (English)

    梁声侃; 宁蕾

    2014-01-01

    柑桔红蜘蛛(Panonychus citri Me Gregor)是柑桔作物上的重要害虫之一,在发生季节遇高温干早及多风环境,则容易传播蔓延成灾,本文从柑桔红蜘蛛发生的危害、生物学特性、生物防治资源、预警监测、防治措施5个方面总结了柑桔红蜘蛛的研究进展,旨在为今后减少柑桔红蜘蛛危害提供参考.

  2. Molecular Characterization of Vitellogenin and Its Receptor Genes from Citrus Red Mite, Panonychus citri (McGregor

    Directory of Open Access Journals (Sweden)

    Rui Zhong

    2015-03-01

    Full Text Available The production and uptake of yolk protein play an important role in the reproduction of all oviparous organisms. Vitellogenin (Vg is the precursor of vitellin (Vn, which is the major egg storage protein, and vitellogenin receptor (VgR is a necessary protein for the uptake of Vg into developing oocytes. In this paper, we characterize the full-length Vg and VgR, PcVg1 and PcVgR, respectively, of the citrus red mite Panonychus citri (McGregor. The PcVg1 cDNA is 5748 nucleotides (nt with a 5553-nt open reading frame (ORF coding for 1851 amino acids (aa, and the PcVgR is 6090 nt, containing an intact ORF of 5673 nt coding an expected protein of 1891 aa. The PcVg1 aa sequence shows a typical GLCG domain and several K/RXXR cleavage sites, and PcVgR comprises two ligand-binding domains, two epidermal growth factor (EGF-like regions containing YWTD motifs, a transmembrane domain, and a cytoplasmic domain. An analysis of the aa sequences and phylogenetics implied that both genes were genetically distinct from those of ticks and insects. The transcriptional profiles determined by real-time quantitative PCR in different developmental stages showed that both genes present the same expressional tendencies in eggs, larvae, nymphs, and adults. This suggested that the biosynthesis and uptake of PcVg occurs coordinately. The strong reproductive capacity of P. citri has been hypothesized as an important factor in its resistance; consequently, understanding the molecular mechanisms regulating Vg and VgR are fundamental for mite control.

  3. Molecular characterization of vitellogenin and its receptor genes from citrus red mite, Panonychus citri (McGregor).

    Science.gov (United States)

    Zhong, Rui; Ding, Tian-Bo; Niu, Jin-Zhi; Xia, Wen-Kai; Liao, Chong-Yu; Dou, Wei; Wang, Jin-Jun

    2015-01-01

    The production and uptake of yolk protein play an important role in the reproduction of all oviparous organisms. Vitellogenin (Vg) is the precursor of vitellin (Vn), which is the major egg storage protein, and vitellogenin receptor (VgR) is a necessary protein for the uptake of Vg into developing oocytes. In this paper, we characterize the full-length Vg and VgR, PcVg1 and PcVgR, respectively, of the citrus red mite Panonychus citri (McGregor). The PcVg1 cDNA is 5748 nucleotides (nt) with a 5553-nt open reading frame (ORF) coding for 1851 amino acids (aa), and the PcVgR is 6090 nt, containing an intact ORF of 5673 nt coding an expected protein of 1891 aa. The PcVg1 aa sequence shows a typical GLCG domain and several K/RXXR cleavage sites, and PcVgR comprises two ligand-binding domains, two epidermal growth factor (EGF)-like regions containing YWTD motifs, a transmembrane domain, and a cytoplasmic domain. An analysis of the aa sequences and phylogenetics implied that both genes were genetically distinct from those of ticks and insects. The transcriptional profiles determined by real-time quantitative PCR in different developmental stages showed that both genes present the same expressional tendencies in eggs, larvae, nymphs, and adults. This suggested that the biosynthesis and uptake of PcVg occurs coordinately. The strong reproductive capacity of P. citri has been hypothesized as an important factor in its resistance; consequently, understanding the molecular mechanisms regulating Vg and VgR are fundamental for mite control. PMID:25739087

  4. Crystallization, data collection and data processing of maltose-binding protein (MalE) from the phytopathogen Xanthomonas axonopodis pv. citri

    International Nuclear Information System (INIS)

    The Xanthomonas axonopodis pv. citri maltose-binding protein MalE has been crystallized at 293 K using the hanging-drop vapour-diffusion method. Maltose-binding protein is the periplasmic component of the ABC transporter responsible for the uptake of maltose/maltodextrins. The Xanthomonas axonopodis pv. citri maltose-binding protein MalE has been crystallized at 293 K using the hanging-drop vapour-diffusion method. The crystal belonged to the primitive hexagonal space group P6122, with unit-cell parameters a = 123.59, b = 123.59, c = 304.20 Å, and contained two molecules in the asymetric unit. It diffracted to 2.24 Å resolution

  5. Targeting juvenile hormone metabolic genes in the Asian citrus psyllid (Diaphorina citri Kuwayama) as a strategy to reduce the spread of citrus greening disease

    OpenAIRE

    Van Ekert, Evelien; Borovsky, D.; Powell, C A; Cave, R. D.; Alessandro, R. T.; Shatters, Jr., R. G.

    2014-01-01

    Diaphorina citri Kuwayama, the Asian citrus psyllid (ACP), is a devastating citrus pest due to its transmission of a phloem-limited bacterial pathogen, Candidatus Liberibacter asiaticus, that causes citrus greening. Psyllid control is a major part of effective greening disease management, and our research targets perturbation of insect juvenile hormone metabolism as a new psyllid control strategy.  Previous studies have shown that application of a juvenile hormone (JH) analogue, pyriproxyfen,...

  6. Detection of Liberibacter asiaticus in a single infected Asian citrus psyllid adult or nymph: Impact of dilution with clean Asian citrus psyllids (Diaphorina citri) during extraction

    OpenAIRE

    LeVesque, Cynthia; Kumagai, Lucita; Bloomquist, Cheryl; Keremane, Manjunath; Lee, Richard; Kunta, Madhurababu; da Graça, John V.; Vidalakis, Georgious; Lin, Hong; Morgan, John; Hall, David G.; Polek, MaryLou

    2014-01-01

    Now that the presence of Huanglongbing (HLB) has been confirmed in California, protecting the state’s citrus industry through early detection of disease is essential in curtailing its spread. Because ‘Candidatus Liberibacter asiaticus’ (Las), the putative causal agent of HLB, accumulates in its vector, the Asian citrus psyllid (ACP), Diaphorina citri, Kuwayama, accurate testing of the insect is vital. Due to the fact that insect secondary metabolites interfere with downstream applications (1,...

  7. Synthesis results from eight years of field testing insecticides against Asian citrus psyllid Diaphorina citri vector of huanglongbing: Considerations and Implications

    OpenAIRE

    Qureshi, Jawwad A.; Kostyk, Barry C; Stansly, Philip A.

    2014-01-01

    Diaphorina citri also known as Asian citrus psyllid (ACP) vectors Candidatus Liberibacter asiaticus, causal organism of the Asian “huanglongbing” or citrus greening disease and therefore needs to be managed effectively.  Forty-three insecticides containing 39 active ingredients (a.i) recommended or experimental were tested during the growing season in foliar sprays (171 treatments, 35 a.i) targeted at flushing trees and soil applications (26 treatments, 6 a.i) to control ACP in citrus between...

  8. Characterization of Chemical Composition of Pericarpium Citri Reticulatae Volatile Oil by Comprehensive Two-Dimensional Gas Chromatography with High-Resolution Time-of-Flight Mass Spectrometry

    OpenAIRE

    Kunming Qin; Lijuan Zheng; Hao Cai; Gang Cao; Yajing Lou; Tulin Lu; Yachun Shu; Wei Zhou; Baochang Cai

    2013-01-01

    Pericarpium Citri Reticulatae (Chenpi in Chinese) has been widely used as an herbal medicine in Korea, China, and Japan. Chenpi extracts are used to treat indigestion and inflammatory syndromes of the respiratory tract such as bronchitis and asthma. This thesis will analyze chemical compositions of Chenpi volatile oil, which was performed by comprehensive two-dimensional gas chromatography with high-resolution time-of-flight mass spectrometry (GC × GC-HR-TOFMS). One hundred and sixty-seven co...

  9. Exposure to Diflubenzuron Results in an Up-Regulation of a Chitin Synthase 1 Gene in Citrus Red Mite, Panonychus citri (Acari: Tetranychidae

    Directory of Open Access Journals (Sweden)

    Wen-Kai Xia

    2014-02-01

    Full Text Available Chitin synthase synthesizes chitin, which is critical for the arthropod exoskeleton. In this study, we cloned the cDNA sequences of a chitin synthase 1 gene, PcCHS1, in the citrus red mite, Panonychus citri (McGregor, which is one of the most economically important pests of citrus worldwide. The full-length cDNA of PcCHS1 contains an open reading frame of 4605 bp of nucleotides, which encodes a protein of 1535 amino acid residues with a predicted molecular mass of 175.0 kDa. A phylogenetic analysis showed that PcCHS1 was most closely related to CHS1 from Tetranychus urticae. During P. citri development, PcCHS1 was constantly expressed in all stages but highly expressed in the egg stage (114.8-fold higher than in the adult. When larvae were exposed to diflubenzuron (DFB for 6 h, the mite had a significantly high mortality rate, and the mRNA expression levels of PcCHS1 were significantly enhanced. These results indicate a promising use of DFB to control P. citri, by possibly acting as an inhibitor in chitin synthesis as indicated by the up-regulation of PcCHS1 after exposure to DFB.

  10. Exposure to diflubenzuron results in an up-regulation of a chitin synthase 1 gene in citrus red mite, Panonychus citri (Acari: Tetranychidae).

    Science.gov (United States)

    Xia, Wen-Kai; Ding, Tian-Bo; Niu, Jin-Zhi; Liao, Chong-Yu; Zhong, Rui; Yang, Wen-Jia; Liu, Bin; Dou, Wei; Wang, Jin-Jun

    2014-01-01

    Chitin synthase synthesizes chitin, which is critical for the arthropod exoskeleton. In this study, we cloned the cDNA sequences of a chitin synthase 1 gene, PcCHS1, in the citrus red mite, Panonychus citri (McGregor), which is one of the most economically important pests of citrus worldwide. The full-length cDNA of PcCHS1 contains an open reading frame of 4605 bp of nucleotides, which encodes a protein of 1535 amino acid residues with a predicted molecular mass of 175.0 kDa. A phylogenetic analysis showed that PcCHS1 was most closely related to CHS1 from Tetranychus urticae. During P. citri development, PcCHS1 was constantly expressed in all stages but highly expressed in the egg stage (114.8-fold higher than in the adult). When larvae were exposed to diflubenzuron (DFB) for 6 h, the mite had a significantly high mortality rate, and the mRNA expression levels of PcCHS1 were significantly enhanced. These results indicate a promising use of DFB to control P. citri, by possibly acting as an inhibitor in chitin synthesis as indicated by the up-regulation of PcCHS1 after exposure to DFB. PMID:24590130

  11. Field Efficacy Trials of Spirotetramat 24% SC on Diaphorina citri Kuwayama and Dialeurodes citri Ashmead and Other Citrus Pests%24%螺虫乙酯SC防治柑橘木虱、粉虱等4种主要害虫田间药效试验

    Institute of Scientific and Technical Information of China (English)

    邓明学; 覃旭; 谭有龙; 翟高云; 甘光耀; 蒋建军; 蓝冰团; 韦巍

    2011-01-01

    [Aims]The field efficacy trials on spirotetramat 24% SC had been conducted to validate the control effect against Dialeurodes citri Ashmead, Phyllocnistis citrella Stainton, Diaphorina citri Kuwayama and Panonychus citri McGregor in May to August in 2010.[Results]The results of field trials showed that the efficacies of l, 3 days after treatment of spirotetramat 24% SC were over 90.1% at 1000 mg/L.The efficacy was lower than 30.2% on the 4th day after treatment against Phylloenistis citrella at 1000 mg/L.Spirotetramat 24% SC provided unstable efficacy against Diaphorina citri Kuwayama.In the first and second tests, it provided good rapid and high efficacy(the control efficacies were over 95% on the 24th day after treatment) against Diaphorina citri Kuwayama at 500 mg/L in May and June.In the third test, the efficacies were lower than 82% during 1 to 15 days after treatment at 333, 500 and 1000 mg/L in August.The efficacies against Panonychus citri were 48.7 to 93.9% during 1 to 22 days after treatment at 500 mg/L.[Conclusions]Spirotetramat 24% SC provided good efficacy against Dialeurodes citri and Panonychus citri and unstable efficacy against Diaphorina citri Kuwayama and poor efficacy against Phyllocnistis citrella.%[目的]为探明螺虫乙酯对柑橘主要害虫的防治效果,于2010年5-8月进行了柑橘粉虱、潜叶蛾、木虱、红蜘蛛的田间药效试验.[结果]24%螺虫乙酯SC 1000 mg/L对柑橘粉虱药后1、3 d的防效高于90.1%;1000 mg/L对柑橘潜叶蛾药后4 d的防效低于30.2%;对柑橘木虱防效不稳定.在5-_6月2次试验中,只有500 mg/L对柑橘木虱防效高(药后24 h防效>95%),在8月的试验中,333、500、1000 mg/L药后1~15 d的防效均低于82%;500 mg/L对柑橘红蜘蛛药后1~22 d的防效为48.7%~93.9%.[结论]24%螺虫乙酯SC对柑橘粉虱、红蜘蛛防效好;对木虱防效不稳定;对潜叶蛾防效差.

  12. Sequence comparisons of plasmids pBJS-O of Spiroplasma citri and pSKU146 of S. kunkelii: implications for plasmid evolution

    Directory of Open Access Journals (Sweden)

    Fletcher Jacqueline

    2005-12-01

    Full Text Available Abstract Background Spiroplasma citri BR3-3X and S. kunkelii CR2-3X cause serious diseases worldwide on citrus and maize species, respectively. S. citri BR3-3X harbors a plasmid, pBJS-Original (pBJS-O, that encodes the spiroplasma adhesion related protein 1 (SARP1, a protein implicated in binding of the pathogen to cells of its leafhopper vector, Circulifer tenellus. The S. kunkelii CR2-3X plasmid, pSKU146, encodes a homolog of SARP1, Sk-ARP1. Due to the close phylogenetic relationship of the two pathogens, we hypothesized that the two plasmids are closely related as well. Results The nucleotide sequence of pBJS-O was determined and compared to the sequences of a plasmid from BR3-T (pBJS-T, which is a multiply passaged leafhopper transmissible derivative of BR3-3X, and to known plasmid sequences including that of pSKU146. In addition to arp1, the 13,374 bp pBJS-O sequence putatively contains nine genes, recognized as open reading frames (ORFs. Several pBJS-O ORFs have homologs on pSKU146. However, the sequences flanking soj-like genes on both plasmids were found to be more distant from one another than sequences in any other region. Further, unlike pSKU146, pBJS-O lacks the conserved oriT region characteristic of the IncP group of bacterial plasmids. We were unable to identify a region in pBJS-O resembling a known plasmid origin of transfer. In regions where sequence was available for the plasmid from both BR3-3X and BR3-T, the pBJS-T sequence had a 0.4 kb deletion relative to its progenitor, pBJS-O. Southern blot hybridization of extrachromosomal DNA from various S. citri strains and spiroplasma species to an arp-specific probe and a probe made from the entire plasmid DNA of BR3-3X revealed limited conservation of both sequences in the genus Spiroplasma. Finally, we also report the presence on the BR3-3X chromosome of arp2, an S. citri homolog of arp1 that encodes the predicted protein SARP2. The C-terminal domain of SARP2 is homologous to that

  13. Spiroplasma citri virus SpV1-derived cloning vector: deletion formation by illegitimate and homologous recombination in a spiroplasmal host strain which probably lacks a functional recA gene.

    OpenAIRE

    Marais, A.; Bové, J M; Renaudin, J

    1996-01-01

    We have previously described the use of the replicative form (RF) of Spiroplasma citri virus SpV1 as a vector for expressing an epitope of the P1 adhesin protein from Mycoplasma pneumoniae in S. citri (A. Marais, J. M. Bové, S.F. Dallo, J. B. Baseman, and J. Renaudin, J. Bacteriol. 175:2783-2787, 1993). We have now studied the structural instability of the recombinant RF leading to loss of the DNA insert. Analyses of viral clones with deletions have shown that both illegitimate and homologous...

  14. Spectroscopic characterization of the exopolysaccharide of Xanthomonas axonopodis pv. citri in Cu{sup 2+} resistance mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Osiro, Denise [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Inst. de Quimica; Franco, Roberto W. Assis; Colnago, Luiz Alberto, E-mail: colnago@cnpdia.embrapa.b [EMBRAPA Instrumentacao Agropecuaria, Sao Carlos, SP (Brazil)

    2011-07-01

    We analyzed the role of exopolysaccharide in the Xanthomonas axonopodis pv. citri (Xac) Cu{sup 2+} resistance mechanism by Fourier transform infrared (FTIR), electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopies. The FTIR data show that cells cultivated in the presence of 0.2 mmol L{sup -1} of CuSO{sub 4} produce larger amounts of pyruvated exopolissacharide (EPS) than the ones cultivated in its absence. The EPR data indicate that the amount of Cu{sup 2+} decreases with cultivation time. The {sup 13}C-CPMAS NMR data also show the complexation of Cu{sup 2+} ions to the EPS. The results demonstrate that EPS plays an important role in Xac Cu{sup 2+} protection. Both capsular and slime EPS act as an initial protection mechanism, binding free Cu{sup 2+} ions, reducing their diffusion and their active transport to the cytoplasm. Cu{sup 2+} also induces the production of a highly pyruvated negative EPS, increasing its capture and binding capacity. (author)

  15. Morphological abnormalities and cell death in the Asian citrus psyllid (Diaphorina citri) midgut associated with Candidatus Liberibacter asiaticus.

    Science.gov (United States)

    Ghanim, Murad; Fattah-Hosseini, Somayeh; Levy, Amit; Cilia, Michelle

    2016-01-01

    Candidatus Liberibacter asiaticus (CLas) is a phloem-limited, gram-negative, fastidious bacterium that is associated with the development of citrus greening disease, also known as Huanglongbing (HLB). CLas is transmitted by the Asian citrus psyllid (ACP) Diaphorina citri, in a circulative manner. Two major barriers to transmission within the insect are the midgut and the salivary glands. We performed a thorough microscopic analysis within the insect midgut following exposure to CLas-infected citrus trees. We observed changes in nuclear architecture, including pyknosis and karyorrhexis as well as changes to the actin cytoskeleton in CLas-exposed midgut cells. Further analyses showed that the changes are likely due to the activation of programmed cell death as assessed by Annexin V staining and DNA fragmentation assays. These results suggest that exposure to CLas-infected trees induces apoptotic responses in the psyllid midgut that should be further investigated. Understanding the adaptive significance of the apoptotic response has the potential to create new approaches for controlling HLB. PMID:27630042

  16. Unreliable pesticide control of the vector psyllid Diaphorina citri (Hemiptera: Psyllidae) for the reduction of microorganism disease transmission.

    Science.gov (United States)

    Ichinose, Katsuya; Miyazi, Kastuhiko; Matsuhira, Kunihiko; Yasuda, Keiji; Sadoyama, Yasutsune; Do, Hong Tuan; Doan, Van Bang

    2010-07-01

    Systemic insecticides and application methods were examined for the control of the vector psyllid of citrus greening disease, Diaphorina citri, on grown king mandarin trees in an orchard in southern Vietnam from May 2007 to September 2008. Leaf spraying of imidacloprid, thiamethoxam, and clothianidin attained about 50 % to 70 % mortality of the psyllid for one month after the application and showed decreased efficacy thereafter. Imidacloprid was more effective than the other two insecticides, but the efficacy on grown trees was still much lower than that following application to young seedlings. Trunk injection of these insecticides accomplished similar mortality, about 50 %, and the efficacy of the insecticides continued for one month. An adjuvant was used with the goal of protecting the insecticide applied on leaves from precipitation, and mineral oil was used for the same reason, as well as its potential to control the psyllid. Neither the adjuvant nor the mineral oil played an evident role in the increase of insecticide efficacy or longevity. Application of systemic insecticides at even 50 times the dose described above did not show an apparent increase in psyllid mortality. The insecticides commonly used for the control of the psyllid were not as effective on this insect on grown trees as we had expected they would be.

  17. Morphological abnormalities and cell death in the Asian citrus psyllid (Diaphorina citri) midgut associated with Candidatus Liberibacter asiaticus.

    Science.gov (United States)

    Ghanim, Murad; Fattah-Hosseini, Somayeh; Levy, Amit; Cilia, Michelle

    2016-01-01

    Candidatus Liberibacter asiaticus (CLas) is a phloem-limited, gram-negative, fastidious bacterium that is associated with the development of citrus greening disease, also known as Huanglongbing (HLB). CLas is transmitted by the Asian citrus psyllid (ACP) Diaphorina citri, in a circulative manner. Two major barriers to transmission within the insect are the midgut and the salivary glands. We performed a thorough microscopic analysis within the insect midgut following exposure to CLas-infected citrus trees. We observed changes in nuclear architecture, including pyknosis and karyorrhexis as well as changes to the actin cytoskeleton in CLas-exposed midgut cells. Further analyses showed that the changes are likely due to the activation of programmed cell death as assessed by Annexin V staining and DNA fragmentation assays. These results suggest that exposure to CLas-infected trees induces apoptotic responses in the psyllid midgut that should be further investigated. Understanding the adaptive significance of the apoptotic response has the potential to create new approaches for controlling HLB.

  18. How does Tremblaya princeps get essential proteins from its nested partner Moranella endobia in the Mealybug Planoccocus citri?

    Directory of Open Access Journals (Sweden)

    Sergio López-Madrigal

    Full Text Available Many insects maintain intracellular mutualistic symbiosis with a wide range of bacteria which are considered essential for their survival (primary or P-endosymbiont and typically suffer drastic genome degradation. Progressive loss of P-endosymbiont metabolic capabilities could lead to the recruitment of co-existent facultative endosymbiont (secondary or S-endosymbiont, thus adding more complexity to the symbiotic system. Planococcus citri, among other mealybug species, harbors an unconventional nested endosymbiotic system where every Tremblaya princeps cell (β-proteobacterium harbors many Moranella endobia cells (γ-proteobacterium. In this system, T. princeps possess one of the smallest prokaryote genome known so far. This extreme genome reduction suggests the supply of many metabolites and essential gene products by M. endobia. Although sporadic cell lysis is plausible, the bacterial participation on the regulation of the predicted molecular exchange (at least to some extent cannot be excluded. Although the comprehensive analysis of the protein translocation ability of M. endobia PCVAL rules out the existence of specific mechanisms for the exportation of proteins from M. endobia to T. princeps, immunolocation of two M. endobia proteins points towards a non-massive but controlled protein provision. We propose a sporadic pattern for the predicted protein exportation events, which could be putatively controlled by the host and/or mediated by local osmotic stress.

  19. An analysis of the small RNA transcriptome of four developmental stages of the citrus red mite (Panonychus citri).

    Science.gov (United States)

    Liu, B; Dou, W; Ding, T-B; Zhong, R; Liao, C-Y; Xia, W-K; Wang, J-J

    2014-04-01

    The citrus red mite (Panonychus citri) can feed on more than 112 plant species around the world. Endogenous small RNAs (sRNAs) have proved to be important components of gene regulation in many eukaryotes. Recently, many sRNAs have been shown to be involved in various biological processes, such as development in many animals, including insects; however, to date, no sRNAs have been reported in the citrus red mite. Using Illumina sequencing, several categories of sRNAs were identified, including 594 known microRNAs (miRNAs) grouped into 206 families and 31 novel miRNAs in the four developmental stages of citrus red mite. In addition, according to bioinformatics analysis and S-Poly(T) miRNA assays, the expression level of many miRNAs varied among the developmental stages. Furthermore, the prediction of miRNAs target genes and their functional annotation indicated that miRNAs are involved in the regulation of multiple pathways in the citrus red mite. As the first report of the sRNA world in citrus red mite, the present study furthers our understanding of the roles played by sRNAs in the development of citrus red mite and the data may help to develop methods of controlling the pests in the field. PMID:24330037

  20. Antioxidant responses of citrus red mite, Panonychus citri (McGregor) (Acari: Tetranychidae), exposed to thermal stress.

    Science.gov (United States)

    Yang, Li-Hong; Huang, Hai; Wang, Jin-Jun

    2010-12-01

    Relatively low or high temperatures are responsible for a variety of physiological stress responses in insects and mites. Induced thermal stress was recently associated with increased reactive oxygen species (ROS) generation, which caused oxidative damage. In this study, we examined the time-related effect of the relatively low (0, 5, 10, and 15 °C) or high (32, 35, 38, and 41 °C) temperatures on the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), peroxidases (POX), and glutathione-S-transferase (GST), and the total antioxidant capacity (TEAC) of the citrus red mite, Panonychus citri (McGregor). The malondialdehyde (MDA) concentration, as a marker of lipid peroxidation in organisms, was also measured in the citrus red mite under thermal stress conditions. Results showed that SOD and GST activities were significantly increased and play an important role in the process of antioxidant response to thermal stress. Lipid peroxidation levels increased significantly (P<0.001) and changed in a time-dependent manner. CAT and POX activity, as well as TEAC, did not vary significantly and play a minor role to remove the ROS generation. These results suggest that thermal stress leads to oxidative stress and antioxidant enzymes play an important role in reducing oxidative damage in the citrus red mite. PMID:20709071

  1. Patogenicidade de Beauveria bassiana ao psilídeo Diaphorina citri e compatibilidade do fungo com produtos fitossanitários

    Directory of Open Access Journals (Sweden)

    Ana Paula Ferreira Pinto

    2012-12-01

    Full Text Available O objetivo deste trabalho foi avaliar a patogenicidade de Beauveria bassiana a ninfas de Diaphorina citri (Hemiptera: Psyllidae e verificar a compatibilidade do fungo com produtos fitossanitários e sua persistência em plantas de citros. Ninfas de D. citri foram pulverizadas com B. bassiana, nas concentrações 5x10(6, 1x10(7, 5x10(7, 1x10(8, 5x10(8 e 1x10(9 conídios mL-1, para determinação da concentração letal. Para avaliação da compatibilidade do fungo com produtos fitossanitários, extrato de nim e cinco inseticidas de quatro grupos químicos diferentes foram incorporados individualmente ao meio de cultura BDA em que o fungo foi cultivado. Avaliaram-se o crescimento vegetativo, a esporulação e a viabilidade do entomopatógeno. Plantas de citros, mantidas em casa de vegetação, foram tratadas primeiramente com os produtos fitossanitários e depois com o entomopatógeno. Avaliaram-se os tempos de exposição de 24 horas e de 7 e 14 dias. O fungo foi patogênico às ninfas de D. citri; a CL50 foi de 0,4x10(7 e a CL90 de 6,7x10(7 conidios mL-1, no décimo dia de avaliação. Em laboratório, os produtos fitosssanitários reduzem o crescimento do fungo. Em casa de vegetação, os produtos não afetam a sobrevivência do fungo nas plantas de citros.

  2. Overview of worldwide diversity of Diaphorina citri Kuwayama mitochondrial cytochrome oxidase 1 haplotypes: two Old World lineages and a New World invasion.

    Science.gov (United States)

    Boykin, L M; De Barro, P; Hall, D G; Hunter, W B; McKenzie, C L; Powell, C A; Shatters, R G

    2012-10-01

    Relationships among worldwide collections of Diaphorina citri (Asian citrus psyllid) were analyzed using mitochondrial cytochrome oxidase I (mtCOI) haplotypes from novel primers. Sequences were produced from PCR amplicons of an 821bp portion of the mtCOI gene using D. citri specific primers, derived from an existing EST library. An alignment was constructed using 612bps of this fragment and consisted of 212 individuals from 52 collections representing 15 countries. There were a total of eight polymorphic sites that separated the sequences into eight different haplotypes (Dcit-1 through Dcit-8). Phylogenetic network analysis using the statistical parsimony software, TCS, suggests two major haplotype groups with preliminary geographic bias between southwestern Asia (SWA) and southeastern Asia (SEA). The recent (within the last 15 to 25 years) invasion into the New World originated from only the SWA group in the northern hemisphere (USA and Mexico) and from both the SEA and SWA groups in the southern hemisphere (Brazil). In only one case, Reunion Island, did haplotypes from both the SEA and SWA group appear in the same location. In Brazil, both groups were present, but in separate locations. The Dcit-1 SWA haplotype was the most frequently encountered, including ~50% of the countries sampled and 87% of the total sequences obtained from India, Pakistan and Saudi Arabia. The second most frequently encountered haplotype, Dcit-2, the basis of the SEA group, represented ~50% of the countries and contained most of the sequences from Southeast Asia and China. Interestingly, only the Caribbean collections (Puerto Rico and Guadeloupe) represented a unique haplotype not found in other countries, indicating no relationship between the USA (Florida) and Caribbean introductions. There is no evidence for cryptic speciation for D. citri based on the COI region included in this study.

  3. The filamentous phage XacF1 causes loss of virulence in Xanthomonas axonopodis pv. citri, the causative agent of citrus canker disease

    OpenAIRE

    Ahmad, Abdelmonim Ali; Askora, Ahmed; Kawasaki, Takeru; Fujie, Makoto; Yamada, Takashi

    2014-01-01

    In this study, filamentous phage XacF1, which can infect Xanthomonas axonopodis pv. citri (Xac) strains, was isolated and characterized. Electron microscopy showed that XacF1 is a member of the family Inoviridae and is about 600 nm long. The genome of XacF1 is 7325 nucleotides in size, containing 13 predicted open reading frames (ORFs), some of which showed significant homology to Ff-like phage proteins such as ORF1 (pII), ORF2 (pV), ORF6 (pIII), and ORF8 (pVI). XacF1 showed a relatively wide...

  4. Cloning and expressing a highly functional and substrate specific farnesoic acid o-methyltransferase from the Asian citrus psyllid (Diaphorina citri Kuwayama).

    Science.gov (United States)

    Van Ekert, Evelien; Shatters, Robert G; Rougé, Pierre; Powell, Charles A; Smagghe, Guy; Borovsky, Dov

    2015-01-01

    The Asian citrus psyllid, Diaphorina citri, transmits a phloem-limited bacterium, Candidatus 'Liberibacter' asiaticus that causes citrus greening disease. Because juvenile hormone (JH) plays an important role in adult and nymphal development, we studied the final steps in JH biosynthesis in D. citri. A putative JH acid methyltransferase ortholog gene (jmtD) and its cognate cDNA were identified by searching D. citri genome database. Expression analysis shows expression in all life stages. In adults, it is expressed in the head-thorax, (containing the corpora allata), and the abdomen (containing ovaries and male accessory glands). A 3D protein model identified the catalytic groove with catalytically active amino acids and the S-adenosyl methionine (SAM)-binding loop. The cDNA was expressed in Escherichia coli cells and the purified enzyme showed high preference for farnesoic acid (FA) and homoFA (kcat of 0.752 × 10(-3) and 0.217 × 10(-3) s(-1), respectively) as compared to JH acid I (JHA I) (cis/trans/cis; 2Z, 6E, 10cis), JHA III (2E, 6E, 10cis), and JHA I (trans/cis/cis; 2E, 2Z, 10cis) (kcat of 0.081 × 10(-3), 0.013 × 10(-3), and 0.003 × 10(-3) s(-1), respectively). This suggests that this ortholog is a DcFA-o-methyl transferase gene (fmtD), not a jmtD, and that JH biosynthesis in D. citri proceeds from FA to JH III through methyl farnesoate (MF). DcFA-o-MT does not require Ca(2+), Mg(2+) or Zn(2+), however, Zn(2+) (1 mM) completely inhibits the enzyme probably by binding H115 at the active groove. This represents the first purified FA-o-MT from Hemiptera with preferred biological activity for FA and not JHA. PMID:25893162

  5. Cloning and expressing a highly functional and substrate specific farnesoic acid o-methyltransferase from the Asian citrus psyllid (Diaphorina citri Kuwayama).

    Science.gov (United States)

    Van Ekert, Evelien; Shatters, Robert G; Rougé, Pierre; Powell, Charles A; Smagghe, Guy; Borovsky, Dov

    2015-01-01

    The Asian citrus psyllid, Diaphorina citri, transmits a phloem-limited bacterium, Candidatus 'Liberibacter' asiaticus that causes citrus greening disease. Because juvenile hormone (JH) plays an important role in adult and nymphal development, we studied the final steps in JH biosynthesis in D. citri. A putative JH acid methyltransferase ortholog gene (jmtD) and its cognate cDNA were identified by searching D. citri genome database. Expression analysis shows expression in all life stages. In adults, it is expressed in the head-thorax, (containing the corpora allata), and the abdomen (containing ovaries and male accessory glands). A 3D protein model identified the catalytic groove with catalytically active amino acids and the S-adenosyl methionine (SAM)-binding loop. The cDNA was expressed in Escherichia coli cells and the purified enzyme showed high preference for farnesoic acid (FA) and homoFA (kcat of 0.752 × 10(-3) and 0.217 × 10(-3) s(-1), respectively) as compared to JH acid I (JHA I) (cis/trans/cis; 2Z, 6E, 10cis), JHA III (2E, 6E, 10cis), and JHA I (trans/cis/cis; 2E, 2Z, 10cis) (kcat of 0.081 × 10(-3), 0.013 × 10(-3), and 0.003 × 10(-3) s(-1), respectively). This suggests that this ortholog is a DcFA-o-methyl transferase gene (fmtD), not a jmtD, and that JH biosynthesis in D. citri proceeds from FA to JH III through methyl farnesoate (MF). DcFA-o-MT does not require Ca(2+), Mg(2+) or Zn(2+), however, Zn(2+) (1 mM) completely inhibits the enzyme probably by binding H115 at the active groove. This represents the first purified FA-o-MT from Hemiptera with preferred biological activity for FA and not JHA.

  6. In silico identification of potential chaperone genes that belong to type III and type IV secretion systems in Xanthomonas axonopodis pv citri

    Directory of Open Access Journals (Sweden)

    Letícia Khater

    2005-01-01

    Full Text Available The secretion of bacterial virulence factors and flagellar components requires the assistance of specific type III and flagellar chaperones. Standard computational annotation of the genome of Xanthomonas axonopodis pv citri, a plant pathogen that causes citrus canker, initially did not identify any genes belonging to these chaperone categories since the primary sequence homology between them was very low. However, in a search for hypothetical proteins with characteristics similar to these chaperones, we have now identified 30 chromosomal and 10 plasmidial potential genes encoding chaperones belonging to types III/IV, and flagellar secretion systems in this organism. The significance of these findings is discussed.

  7. Exposure to Diflubenzuron Results in an Up-Regulation of a Chitin Synthase 1 Gene in Citrus Red Mite, Panonychus citri (Acari: Tetranychidae)

    OpenAIRE

    Wen-Kai Xia; Tian-Bo Ding; Jin-Zhi Niu; Chong-Yu Liao; Rui Zhong; Wen-Jia Yang; Bin Liu; Wei Dou; Jin-Jun Wang

    2014-01-01

    Chitin synthase synthesizes chitin, which is critical for the arthropod exoskeleton. In this study, we cloned the cDNA sequences of a chitin synthase 1 gene, PcCHS1, in the citrus red mite, Panonychus citri (McGregor), which is one of the most economically important pests of citrus worldwide. The full-length cDNA of PcCHS1 contains an open reading frame of 4605 bp of nucleotides, which encodes a protein of 1535 amino acid residues with a predicted molecular mass of 175.0 kDa. A phylogenetic ...

  8. Biologia e tabela de vida de fertilidade de Planococcus citri em diferentes estruturas vegetativas de cultivares de videira Biology and fertility life table of Planococcus citri in different vegetative structures of grape cultivars

    Directory of Open Access Journals (Sweden)

    Wilson José Morandi Filho

    2008-08-01

    Full Text Available O objetivo deste trabalho foi estudar a biologia e a tabela de vida de fertilidade de Planococcus citri, em folhas de videira das cultivares Cabernet Sauvignon, Itália e Isabel, em bagas de uva 'Itália' e em raízes da 'Isabel' e dos porta-enxertos 101-14 e IAC-572. Os seguintes parâmetros foram avaliados: duração e viabilidade dos estágios de ovo e ninfa; e fecundidade e longevidade dos adultos. Em raízes do porta-enxerto IAC-572, a cochonilha não completou o ciclo biológico. Em bagas de uva 'Itália', o inseto completou a fase de ninfa, porém os adultos foram inférteis. Em folhas das diferentes cultivares, a duração média do período de ovo a adulto dos machos foi de 24,63 dias, com viabilidade de 32%, enquanto as fêmeas duraram 32 dias com viabilidade de 56%. Em raízes, a duração do ciclo biológico de fêmeas e machos foi de 32,45 e 29,50 dias, respectivamente. Em folhas, a fecundidade foi de 67,27, 66,09 e 53,33 ovos por fêmea, nas cultivares Cabernet Sauvignon, Isabel e Itália, respectivamente. Nas raízes foram obtidos 30,4 e 70,0 ovos por fêmea, no porta-enxerto 101-14 e na cultivar Isabel, respectivamente.The objective of this work was to study the biology and fertility life table of Planococcus citri in leaves of the grape cultivars Cabernet Sauvignon, Itália and Isabel, in berries of 'Itália', in roots of 'Isabel' and 101-14 and IAC-572 rootstocks. The following parameters were evaluated: duration and viability of the egg and nymph stages; and fertility and longevity of the adults. On berries of 'Itália', the insect completed the nymph phase, however the adults were infertile. On roots of the rootstock IAC-572, citrus mealybug was unable to develop. On leaves of the grape cultivars, the period of egg to adult males was 24.63 days, with viability of 32%, while females lasted 32 days with viability of 56%. On roots, the duration of the cycle of females and males was 32.45 and 29.50 days, respectively. For females

  9. Assessment of Prey Preference by the Generalist Predator, Mallada basalis (Walker), When Offered Two Species of Spider Mites, Tetranychus kanzawai Kishida and Panonychus citri (McGregor) on Papaya

    Science.gov (United States)

    We investigated potential prey preference of the generalist predator Mallada basalis (Walker) when offered two mites, Tetranychus kanzawai Kishida and Panonychus citri (McGregor), both important pests on papaya. Laboratory choice tests revealed that none of the three larval instars of M. basalis sho...

  10. Impact of different temperatures on survival and energy metabolism in the Asian citrus psyllid, Diaphorina citri Kuwayama.

    Science.gov (United States)

    El-Shesheny, Ibrahim; Hijaz, Faraj; El-Hawary, Ibrahim; Mesbah, Ibrahim; Killiny, Nabil

    2016-02-01

    Temperature influences the life history and metabolic parameters of insects. Asian citrus psyllid (ACP), Diaphorina citri is a tropical and subtropical pest. ACP invaded new regions around the world and threatened the citrus industry as a vector for Huanglongbing (HLB) disease. ACP is widely distributed and can survive high (up to 45 °C) and low temperatures (as low as -6 °C). The precise mechanism of temperature tolerance in ACP is poorly understood. We investigated adult survival, cellular energy balance, gene expression, and nucleotide and sugar-nucleotide changes under the effect of different temperature regimes (0 °C to 45 °C with 5 °C intervals). The optimum temperatures for survival were 20 and 25 °C. Low temperatures of 0 °C and 5 °C caused 50% mortality after 2 and 4 days respectively, while one day at high temperature (40 °C and 45 °C) caused more than 95% mortality. The lowest quantity of ATP (3.69 ± 1.6 ng/insect) and the maximum ATPase enzyme activities (57.43 ± 7.6 μU/insect) were observed at 25 °C. Correlation between ATP quantities and ATPase activity was negative. Gene expression of hsp 70, V-type proton ATPase catalytic subunit A and ATP synthase α subunit matched these results. Twenty-four nucleotides and sugar-nucleotides were quantified using HPLC in ACP adults maintained at low, high, and optimum temperatures. The nucleotide profiles were different among treatments. The ratios between AMP:ATP and ADP:ATP were significantly decreased and positively correlated to adults survival, whereas the adenylate energy charge was increased in response to low and high temperatures. Exploring energy metabolic regulation in relation with adult survival might help in understanding the physiological basis of how ACP tolerates newly invaded regions. PMID:26603556

  11. Effects of temperature on population growth parameters of Cryptolaemus montrouzieri (Coleoptera: Coccinellidae reared on Planococcus citri (Homoptera: Pseudococcidae

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    Negar Saeedi

    2015-09-01

    Full Text Available The effect of temperature on the development, survival, fecundity and population growth parameters of Cryptolaemus montrouzieri Mulsant (Col.: Coccinellidae reared on Planococcus citri Risso (Hom.: Pseudococcidae was determined at five constant temperatures (18, 22, 26, 30 and 32±1°C in the laboratory conditions. Results showed a temperature - dependent development of the coccinellid. The mean total of immature period was estimated 76.6±0.9, 33.9±0.1, 25.8±0.1, 22.6±0.1 and 26.2±1.4 days at 18, 22, 26, 30 and 32°C, respectively. The highest and lowest values of R0, rm and λ were obtained 369.9±50.2 and 2.5±0.8 (female/female/generation, 0.07±0.01 and 0.02±0.01 (female/female/day and 1.08±0.01 and 1.02±0.01 (day-1 at 26 and 32°C, respectively. The lowest values of generation time (T and doubling time (Dt were calculated 42.2±0.9 and 8.9±0.5 days at 32 and 26°C, respectively. The lower and higher developmental threshold of total of immature period were obtained 11.5 and 25.5°C, respectively. The thermal requirement for completion of total of immature period of this predator were estimated 400 DD. These results showed that 26°C and/or adjacent temperature is most suitable for mass rearing of this predator.

  12. Impact of different temperatures on survival and energy metabolism in the Asian citrus psyllid, Diaphorina citri Kuwayama.

    Science.gov (United States)

    El-Shesheny, Ibrahim; Hijaz, Faraj; El-Hawary, Ibrahim; Mesbah, Ibrahim; Killiny, Nabil

    2016-02-01

    Temperature influences the life history and metabolic parameters of insects. Asian citrus psyllid (ACP), Diaphorina citri is a tropical and subtropical pest. ACP invaded new regions around the world and threatened the citrus industry as a vector for Huanglongbing (HLB) disease. ACP is widely distributed and can survive high (up to 45 °C) and low temperatures (as low as -6 °C). The precise mechanism of temperature tolerance in ACP is poorly understood. We investigated adult survival, cellular energy balance, gene expression, and nucleotide and sugar-nucleotide changes under the effect of different temperature regimes (0 °C to 45 °C with 5 °C intervals). The optimum temperatures for survival were 20 and 25 °C. Low temperatures of 0 °C and 5 °C caused 50% mortality after 2 and 4 days respectively, while one day at high temperature (40 °C and 45 °C) caused more than 95% mortality. The lowest quantity of ATP (3.69 ± 1.6 ng/insect) and the maximum ATPase enzyme activities (57.43 ± 7.6 μU/insect) were observed at 25 °C. Correlation between ATP quantities and ATPase activity was negative. Gene expression of hsp 70, V-type proton ATPase catalytic subunit A and ATP synthase α subunit matched these results. Twenty-four nucleotides and sugar-nucleotides were quantified using HPLC in ACP adults maintained at low, high, and optimum temperatures. The nucleotide profiles were different among treatments. The ratios between AMP:ATP and ADP:ATP were significantly decreased and positively correlated to adults survival, whereas the adenylate energy charge was increased in response to low and high temperatures. Exploring energy metabolic regulation in relation with adult survival might help in understanding the physiological basis of how ACP tolerates newly invaded regions.

  13. [Rapid Identification of Epicarpium Citri Grandis via Infrared Spectroscopy and Fluorescence Spectrum Imaging Technology Combined with Neural Network].

    Science.gov (United States)

    Pan, Sha-sha; Huang, Fu-rong; Xiao, Chi; Xian, Rui-yi; Ma, Zhi-guo

    2015-10-01

    To explore rapid reliable methods for detection of Epicarpium citri grandis (ECG), the experiment using Fourier Transform Attenuated Total Reflection Infrared Spectroscopy (FTIR/ATR) and Fluorescence Spectrum Imaging Technology combined with Multilayer Perceptron (MLP) Neural Network pattern recognition, for the identification of ECG, and the two methods are compared. Infrared spectra and fluorescence spectral images of 118 samples, 81 ECG and 37 other kinds of ECG, are collected. According to the differences in tspectrum, the spectra data in the 550-1 800 cm(-1) wavenumber range and 400-720 nm wavelength are regarded as the study objects of discriminant analysis. Then principal component analysis (PCA) is applied to reduce the dimension of spectroscopic data of ECG and MLP Neural Network is used in combination to classify them. During the experiment were compared the effects of different methods of data preprocessing on the model: multiplicative scatter correction (MSC), standard normal variable correction (SNV), first-order derivative(FD), second-order derivative(SD) and Savitzky-Golay (SG). The results showed that: after the infrared spectra data via the Savitzky-Golay (SG) pretreatment through the MLP Neural Network with the hidden layer function as sigmoid, we can get the best discrimination of ECG, the correct percent of training set and testing set are both 100%. Using fluorescence spectral imaging technology, corrected by the multiple scattering (MSC) results in the pretreatment is the most ideal. After data preprocessing, the three layers of the MLP Neural Network of the hidden layer function as sigmoid function can get 100% correct percent of training set and 96.7% correct percent of testing set. It was shown that the FTIR/ATR and fluorescent spectral imaging technology combined with MLP Neural Network can be used for the identification study of ECG and has the advantages of rapid, reliable effect. PMID:26904814

  14. Genome-wide mutagenesis of Xanthomonas axonopodis pv. citri reveals novel genetic determinants and regulation mechanisms of biofilm formation.

    Directory of Open Access Journals (Sweden)

    Jinyun Li

    Full Text Available Xanthomonas axonopodis pv. citri (Xac causes citrus canker disease, a major threat to citrus production worldwide. Accumulating evidence suggests that the formation of biofilms on citrus leaves plays an important role in the epiphytic survival of this pathogen prior to the development of canker disease. However, the process of Xac biofilm formation is poorly understood. Here, we report a genome-scale study of Xac biofilm formation in which we identified 92 genes, including 33 novel genes involved in biofilm formation and 7 previously characterized genes, colR, fhaB, fliC, galU, gumD, wxacO, and rbfC, known to be important for Xac biofilm formation. In addition, 52 other genes with defined or putative functions in biofilm formation were identified, even though they had not previously reported been to be associated with biofilm formation. The 92 genes were isolated from 292 biofilm-defective mutants following a screen of a transposon insertion library containing 22,000 Xac strain 306 mutants. Further analyses indicated that 16 of the novel genes are involved in the production of extracellular polysaccharide (EPS and/or lipopolysaccharide (LPS, 7 genes are involved in signaling and regulatory pathways, and 5 genes have unknown roles in biofilm formation. Furthermore, two novel genes, XAC0482, encoding a haloacid dehalogenase-like phosphatase, and XAC0494 (designated as rbfS, encoding a two-component sensor protein, were confirmed to be biofilm-related genes through complementation assays. Our data demonstrate that the formation of mature biofilm requires EPS, LPS, both flagellum-dependent and flagellum-independent cell motility, secreted proteins and extracellular DNA. Additionally, multiple signaling pathways are involved in Xac biofilm formation. This work is the first report on a genome-wide scale of the genetic processes of biofilm formation in plant pathogenic bacteria. The report provides significant new information about the genetic

  15. Analysis of transcriptome differences between resistant and susceptible strains of the citrus red mite Panonychus citri (Acari: Tetranychidae.

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    Bin Liu

    Full Text Available BACKGROUND: The citrus red mite is a worldwide citrus pest and a common sensitizing allergen of asthma and rhinitis. It has developed strong resistance to many registered acaricides, However, the molecular mechanisms of resistance remain unknown. we therefore used next generation sequencing technology to investigate the global transcriptomes between resistant strains and susceptible strains. RESULTS: We obtained 34,159, 30,466 and 32,217 unigenes by assembling the SS reads, RS reads and SS&RS reads respectively. There are total 17,581 annotated unigenes from SS&RS reads by BLAST searching databases of nr, the Clusters of Orthologous Groups (COGs and Kyoto Encyclopedia of Genes and Genomes (KEGG with an E-value ≤ 1e-5, in which 7,075 unigenes were annotated in the COG database, 12, 712 unigenes were found in the KEGG database and 3,812 unigenes were assigned to Gene ontology (GO. Moreover, 2,701 unigenes were judged to be the differentially expressed genes (DEGs based on the uniquely mapped reads. There are 219 pathways in all annotated unigenes and 198 pathways in DEGs that mapped to the KEGG database. We identified 211 metabolism genes and target genes related to general insecticide resistance such as P450 and Cytochrome b, and further compared their differences between RS and SS. Meanwhile, we identified 105 and 194 genes related to growth and reproduction, respectively, based on the mode of action of Hexythiazox. After further analyses, we found variation in sequences but not in gene expression related to mite growth and reproduction between different strains. CONCLUSION: To our knowledge, this is the first comparative transcriptome study to discover candidate genes involved in phytophagous mite resistance. This study identified differential unigenes related to general pesticide resistance and organism growth and reproduction in P. citri. The assembled, annotated transcriptomes provide a valuable genomic resource for further understanding

  16. 橘叶黄酮类成分的研究与薄层色谱鉴别%Studies on Flavonoids of Folium Citri Reticulatae and Identification by Thin Layer Chromatography

    Institute of Scientific and Technical Information of China (English)

    汪金玉; 帅欧; 林励; 庄满贤; 苏昭仑; 黄振

    2011-01-01

    [目的]分离、鉴定橘叶中黄酮类成分,并以所得到的黄酮类成分为对照品建立其薄层色谱鉴别方法,为橘叶的质量控制提供科学依据.[方法]以硅胶柱层析法分离橘叶黄酮类成分,采用核磁共振法进行结构鉴定,并以所得黄酮类成分为对照品,对橘叶药材进行硅胶薄层色谱鉴别.[结果]从橘叶中分离得到川陈皮素、5-去甲川陈皮素、橘红素、异橙黄酮,所建立的薄层色谱图斑点清晰,分离度良好.[结论]首次从橘叶中分离得到川陈皮素等4种黄酮类化合物,新建立的橘叶薄层鉴别方法薄层行为良好,适用于橘叶的鉴别.%Objective To separate and identify the flavonoids from Folium Citri Reticulatae, and to establish a thin layer chromatogram ( TLC ) method for the identification of Folium Citri Reticulatae with flavonoids as the reference substance. Methods We separated flavonoids of Folium Citri Reticulatae by silica gel column chromatography and identified their structure by nuclear magnetic resonance (NMR) and mass spectrometry (MS). With the obtained flavonoids as reference substance, we identified the medicinal material of Folium Citri Reticulatae by silica gel TLC. Results Nobiletin, 5-demethyl nobiletin, tangeretin, and isosinensetin were isolated from Folium Citri Reticulatae successfully. The established thin layer chromatogram spots were clear, with good separation.Conclusion Flavonoids such as nobiletin, 5-demethyl nobiletin, tangeretin, and isosinensetin have been isolated from Folium Citri Reticulatae for the first time. The established TLC method is efficient and suitable for the identification of Folium Citri Reticulatae.

  17. Comparison of Ensemble Strategies in Online NIR for Monitoring the Extraction Process of Pericarpium Citri Reticulatae Based on Different Variable Selections.

    Science.gov (United States)

    Zhou, Zheng; Li, Yang; Zhang, Qiao; Shi, Xinyuan; Wu, Zhisheng; Qiao, Yanjiang

    2016-01-01

    Different ensemble strategies were compared in online near-infrared models for monitoring active pharmaceutical ingredients of Traditional Chinese Medicine. Bagging partial least square regression and boosting partial least square regression were adopted to near-infrared models, to determine hesperidin and nobiletin content during the extraction process of Pericarpium Citri Reticulatae in a pilot scale system. Different pretreatment methods were investigated, including Savitzky-Golay smoothing, derivatives, multiplicative scatter correction, standard normal variate, normalize, and combinations of them. Two different variable selection methods, including synergy interval partial least squares and backward interval partial least squares algorithms, were performed. Based on the result of the synergy interval partial least squares algorithm, bagging partial least square regression and boosting partial least square regression were adopted into the quantitative analysis. The results demonstrated that the established approach could be applied for rapid determination and real-time monitoring of hesperidin and nobiletin in Pericarpium Citri Reticulatae (Citrus reticulata) during the extraction process. Comparing the results, the boosting partial least square regression provided a slightly better accuracy than the bagging partial least square regression. Finally, this paper provides a promising ensemble strategy on online near-infrared models in Chinese medicine. PMID:26485639

  18. Innate and Conditioned Responses to Chemosensory and Visual Cues in Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae), Vector of Huanglongbing Pathogens.

    Science.gov (United States)

    Patt, Joseph M; Stockton, Dara; Meikle, William G; Sétamou, Mamoudou; Mafra-Neto, Agenor; Adamczyk, John J

    2014-01-01

    Asian citrus psyllid (Diaphorina citri) transmits Huanglongbing, a devastating disease that threatens citrus trees worldwide. A better understanding of the psyllid's host-plant selection process may lead to the development of more efficient means of monitoring it and predicting its movements. Since behavioral adaptations, such as associative learning, may facilitate recognition of suitable host-plants, we examined whether adult D. citri could be conditioned to visual and chemosensory stimuli from host and non-host-plant sources. Response was measured as the frequency of salivary sheaths, the residue of psyllid probing activity, in a line of emulsified wax on the surface of a test arena. The psyllids displayed both appetitive and aversive conditioning to two different chemosensory stimuli. They could also be conditioned to recognize a blue-colored probing substrate and their response to neutral visual cues was enhanced by chemosensory stimuli. Conditioned psyllids were sensitive to the proportion of chemosensory components present in binary mixtures. Naïve psyllids displayed strong to moderate innate biases to several of the test compounds. While innate responses are probably the psyllid's primary behavioral mechanism for selecting host-plants, conditioning may enhance its ability to select host-plants during seasonal transitions and dispersal. PMID:26462949

  19. Trial on trapping effect of the Diaphorina citri trappers%柑橘木虱诱捕器诱捕效果试验

    Institute of Scientific and Technical Information of China (English)

    钟明星

    2015-01-01

    Effects of controlling pests of Diaphorina citri by the yellow plate pheromone trappers with different hanging heights and positions were comparatively studied. The results showed that the most amount of Diaphorina citri was trapped when trapper hanged at the middle of the canopy( 1. 5 m high),followed by hanged at the lower of the canopy(0. 8 m high),and the worst effect at the upper of the canopy(2. 0 m high). Among different positions,the best trapping effect was achieved when hanged at the north of the canopy,then the west and south,and the worst effect at the east of the canopy.%研究黄板信息素诱捕器不同悬挂高度与悬挂方位对柑橘木虱诱集效果的影响,结果表明:诱捕器悬挂在树冠中层(1.5 m)诱集的虫量最多,其次为树冠下层(0.8 m),树冠上层(2.0 m)诱集效果最差;诱捕器悬挂在树冠北面诱集的虫量最多,其次为树冠西面和树冠南面,树冠东面诱集效果最差。

  20. Innate and Conditioned Responses to Chemosensory and Visual Cues in Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae, Vector of Huanglongbing Pathogens

    Directory of Open Access Journals (Sweden)

    Joseph M. Patt

    2014-11-01

    Full Text Available Asian citrus psyllid (Diaphorina citri transmits Huanglongbing, a devastating disease that threatens citrus trees worldwide. A better understanding of the psyllid’s host-plant selection process may lead to the development of more efficient means of monitoring it and predicting its movements. Since behavioral adaptations, such as associative learning, may facilitate recognition of suitable host-plants, we examined whether adult D. citri could be conditioned to visual and chemosensory stimuli from host and non-host-plant sources. Response was measured as the frequency of salivary sheaths, the residue of psyllid probing activity, in a line of emulsified wax on the surface of a test arena. The psyllids displayed both appetitive and aversive conditioning to two different chemosensory stimuli. They could also be conditioned to recognize a blue-colored probing substrate and their response to neutral visual cues was enhanced by chemosensory stimuli. Conditioned psyllids were sensitive to the proportion of chemosensory components present in binary mixtures. Naïve psyllids displayed strong to moderate innate biases to several of the test compounds. While innate responses are probably the psyllid’s primary behavioral mechanism for selecting host-plants, conditioning may enhance its ability to select host-plants during seasonal transitions and dispersal.

  1. Innate and Conditioned Responses to Chemosensory and Visual Cues in Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae), Vector of Huanglongbing Pathogens.

    Science.gov (United States)

    Patt, Joseph M; Stockton, Dara; Meikle, William G; Sétamou, Mamoudou; Mafra-Neto, Agenor; Adamczyk, John J

    2014-01-01

    Asian citrus psyllid (Diaphorina citri) transmits Huanglongbing, a devastating disease that threatens citrus trees worldwide. A better understanding of the psyllid's host-plant selection process may lead to the development of more efficient means of monitoring it and predicting its movements. Since behavioral adaptations, such as associative learning, may facilitate recognition of suitable host-plants, we examined whether adult D. citri could be conditioned to visual and chemosensory stimuli from host and non-host-plant sources. Response was measured as the frequency of salivary sheaths, the residue of psyllid probing activity, in a line of emulsified wax on the surface of a test arena. The psyllids displayed both appetitive and aversive conditioning to two different chemosensory stimuli. They could also be conditioned to recognize a blue-colored probing substrate and their response to neutral visual cues was enhanced by chemosensory stimuli. Conditioned psyllids were sensitive to the proportion of chemosensory components present in binary mixtures. Naïve psyllids displayed strong to moderate innate biases to several of the test compounds. While innate responses are probably the psyllid's primary behavioral mechanism for selecting host-plants, conditioning may enhance its ability to select host-plants during seasonal transitions and dispersal.

  2. Characterization and functional analysis of a novel glutathione S-transferase gene potentially associated with the abamectin resistance in Panonychus citri (McGregor).

    Science.gov (United States)

    Liao, Chong-Yu; Xia, Wen-Kai; Feng, Ying-Cai; Li, Gang; Liu, Hai; Dou, Wei; Wang, Jin-Jun

    2016-09-01

    The citrus red mite, Panonychus citri (McGregor), a major citrus pest distributed worldwide, has been found to be resistant to various insecticides and acaricides used in China. However, the molecular mechanisms associated with the abamectin resistance in this species have not yet been reported. In this study, results showed over-expression of a novel glutathione S-transferases (GSTs) gene (PcGSTm5) in abamectin-resistant P. citri. Quantitative real-time PCR analysis showed that the transcripts of PcGSTm5 were also significantly up-regulated after exposure to abamectin and the maximum mRNA expression level at nymphal stage. The recombinant protein of PcGSTm5-pET-28a produced by Escherichia coli showed a pronounced activity toward the conjugates of 1-chloro-2,4 dinitrobenzene (CDNB) and glutathione (GSH). The kinetics of CDNB and GSH and its optimal pH and thermal stability were also determined. Reverse genetic study through a new method of leaf-mediated dsRNA feeding further support a link between the expression of PcGSTm5 and abamectin resistance. However, no direct evidence was found in metabolism or inhibition assays to confirm the hypothesis that PcGSTm5 can metabolize abamectin. Finally, it is here speculated that PcGSTm5 may play a role in abamectin detoxification through other pathway such as the antioxidant protection.

  3. Characterization and functional analysis of a novel glutathione S-transferase gene potentially associated with the abamectin resistance in Panonychus citri (McGregor).

    Science.gov (United States)

    Liao, Chong-Yu; Xia, Wen-Kai; Feng, Ying-Cai; Li, Gang; Liu, Hai; Dou, Wei; Wang, Jin-Jun

    2016-09-01

    The citrus red mite, Panonychus citri (McGregor), a major citrus pest distributed worldwide, has been found to be resistant to various insecticides and acaricides used in China. However, the molecular mechanisms associated with the abamectin resistance in this species have not yet been reported. In this study, results showed over-expression of a novel glutathione S-transferases (GSTs) gene (PcGSTm5) in abamectin-resistant P. citri. Quantitative real-time PCR analysis showed that the transcripts of PcGSTm5 were also significantly up-regulated after exposure to abamectin and the maximum mRNA expression level at nymphal stage. The recombinant protein of PcGSTm5-pET-28a produced by Escherichia coli showed a pronounced activity toward the conjugates of 1-chloro-2,4 dinitrobenzene (CDNB) and glutathione (GSH). The kinetics of CDNB and GSH and its optimal pH and thermal stability were also determined. Reverse genetic study through a new method of leaf-mediated dsRNA feeding further support a link between the expression of PcGSTm5 and abamectin resistance. However, no direct evidence was found in metabolism or inhibition assays to confirm the hypothesis that PcGSTm5 can metabolize abamectin. Finally, it is here speculated that PcGSTm5 may play a role in abamectin detoxification through other pathway such as the antioxidant protection. PMID:27521916

  4. Control Test against Panonychus citri which Damaged Poplar with Different Drugs%杨树黄叶螨不同药物防治试验

    Institute of Scientific and Technical Information of China (English)

    孙玉鹏; 孙玉梅

    2016-01-01

    通过对朝阳市杨树黄叶螨进行不同药物不同浓度防治试验,结果表明:喷洒不同药物对杨树黄叶螨杀虫效果差异显著,以杀螨醇和敌螨丹2种农药杀虫效果最好,杀螨率分别为99.3%~100%和99.4%~100%;不同浓度的杀螨醇杀虫效果差异极显著,以400倍浓度效果最好,叶螨死亡率在99.7%以上。%Controlling experiments of Panonychus citri which damaged poplar in Chaoyang City with different drug and concentrations were conducted.Result shows that spraying different drugs on Panonychus citri have significant differences;the effect of insect disinfestation to chorobenzilate and chlorfensulphide are optimal.The death rate is 99.3%-100% and 99.4%-100%;the effect of insect disinfestation for different concentrations of chorobenzilate is significantly different ;the effect of 400-fold concentration of chorobenzilate is the optimal.The death rate are 99.7%or more.

  5. Research of Exocarpium Citri Grandis Fingerprint Based on Self-organization Competitive Neural Network%基于自组织竞争型神经网络的化橘红指纹图谱研究

    Institute of Scientific and Technical Information of China (English)

    陈南迪; 卢丽萍; 汪金玉; 林励

    2012-01-01

    Objective To establish the self-organization competitive neural network method for identifying the species by the fingerprints of different kinds of Exocarpium Citri Grandis(Cirtus grandis Peel). Methods The fingerprints of different species of Exocarpium Citri Grandis were established by fourier transform infrared speetroscopy and high performance liquid chromatogram (HPLC). And then we used the self-organization competitive neural network model to distinguish the different species of Exocarpium Citri Grandis. Results The self-organization competitive neural network for distinguish Exocarpium Citri Grandis of different species was established, and the rate of accuracy for infrared and HPLC fingerprint of the powder and the extract was more than 91.67 % in average. Conclusion The self-organizing competitiveneural network can be used for distinguishing different species of Exocarpium Citri Grandis by their fingerprints.%目的 建立不同品种化橘红指纹图谱的自组织竞争型人工神经网络判别方法.方法 采用傅里叶红外光谱法及HPLC法建立不同品种化橘红的指纹图谱,采用自组织竞争型人工神经网络进行模式识别.结果 自组织竞争型神经网络模型对化橘红粉末、提取物红外及HPLC指纹图谱预测平均准确率达91.67%以上.结论 自组织竞争型人工神经网络可有效用于化橘红品种的识别.

  6. Infection Density Dynamics of the Citrus Greening Bacterium "Candidatus Liberibacter asiaticus" in Field Populations of the Psyllid Diaphorina citri and Its Relevance to the Efficiency of Pathogen Transmission to Citrus Plants.

    Science.gov (United States)

    Ukuda-Hosokawa, Rie; Sadoyama, Yasutsune; Kishaba, Misaki; Kuriwada, Takashi; Anbutsu, Hisashi; Fukatsu, Takema

    2015-06-01

    Huanglongbing, or citrus greening, is a devastating disease of citrus plants recently spreading worldwide, which is caused by an uncultivable bacterial pathogen, "Candidatus Liberibacter asiaticus," and vectored by a phloem-sucking insect, Diaphorina citri. We investigated the infection density dynamics of "Ca. Liberibacter asiaticus" in field populations of D. citri with experiments using field-collected insects to address how "Ca. Liberibacter asiaticus" infection density in the vector insect is relevant to pathogen transmission to citrus plants. Of 500 insects continuously collected from "Ca. Liberibacter asiaticus"-infected citrus trees with pathological symptoms in the spring and autumn of 2009, 497 (99.4%) were "Ca. Liberibacter asiaticus" positive. The infections were systemic across head-thorax and abdomen, ranging from 10(3) to 10(7) bacteria per insect. In spring, the infection densities were low in March, at ∼ 10(3) bacteria per insect, increasing up to 10(6) to 10(7) bacteria per insect in April and May, and decreasing to 10(5) to 10(6) bacteria per insect in late May, whereas the infection densities were constantly ∼ 10(6) to 10(7) bacteria per insect in autumn. Statistical analysis suggested that several factors, such as insect sex, host trees, and collection dates, may be correlated with "Ca. Liberibacter asiaticus" infection densities in field D. citri populations. Inoculation experiments with citrus seedlings using field-collected "Ca. Liberibacter asiaticus"-infected insects suggested that (i) "Ca. Liberibacter asiaticus"-transmitting insects tend to exhibit higher infection densities than do nontransmitting insects, (ii) a threshold level (∼ 10(6) bacteria per insect) of "Ca. Liberibacter asiaticus" density in D. citri is required for successful transmission to citrus plants, and (iii) D. citri attaining the threshold infection level transmits "Ca. Liberibacter asiaticus" to citrus plants in a stochastic manner. These findings provide

  7. Infection Density Dynamics of the Citrus Greening Bacterium “Candidatus Liberibacter asiaticus” in Field Populations of the Psyllid Diaphorina citri and Its Relevance to the Efficiency of Pathogen Transmission to Citrus Plants

    Science.gov (United States)

    Ukuda-Hosokawa, Rie; Sadoyama, Yasutsune; Kishaba, Misaki; Kuriwada, Takashi; Anbutsu, Hisashi

    2015-01-01

    Huanglongbing, or citrus greening, is a devastating disease of citrus plants recently spreading worldwide, which is caused by an uncultivable bacterial pathogen, “Candidatus Liberibacter asiaticus,” and vectored by a phloem-sucking insect, Diaphorina citri. We investigated the infection density dynamics of “Ca. Liberibacter asiaticus” in field populations of D. citri with experiments using field-collected insects to address how “Ca. Liberibacter asiaticus” infection density in the vector insect is relevant to pathogen transmission to citrus plants. Of 500 insects continuously collected from “Ca. Liberibacter asiaticus”-infected citrus trees with pathological symptoms in the spring and autumn of 2009, 497 (99.4%) were “Ca. Liberibacter asiaticus” positive. The infections were systemic across head-thorax and abdomen, ranging from 103 to 107 bacteria per insect. In spring, the infection densities were low in March, at ∼103 bacteria per insect, increasing up to 106 to 107 bacteria per insect in April and May, and decreasing to 105 to 106 bacteria per insect in late May, whereas the infection densities were constantly ∼106 to 107 bacteria per insect in autumn. Statistical analysis suggested that several factors, such as insect sex, host trees, and collection dates, may be correlated with “Ca. Liberibacter asiaticus” infection densities in field D. citri populations. Inoculation experiments with citrus seedlings using field-collected “Ca. Liberibacter asiaticus”-infected insects suggested that (i) “Ca. Liberibacter asiaticus”-transmitting insects tend to exhibit higher infection densities than do nontransmitting insects, (ii) a threshold level (∼106 bacteria per insect) of “Ca. Liberibacter asiaticus” density in D. citri is required for successful transmission to citrus plants, and (iii) D. citri attaining the threshold infection level transmits “Ca. Liberibacter asiaticus” to citrus plants in a stochastic manner. These

  8. Infection Density Dynamics of the Citrus Greening Bacterium "Candidatus Liberibacter asiaticus" in Field Populations of the Psyllid Diaphorina citri and Its Relevance to the Efficiency of Pathogen Transmission to Citrus Plants.

    Science.gov (United States)

    Ukuda-Hosokawa, Rie; Sadoyama, Yasutsune; Kishaba, Misaki; Kuriwada, Takashi; Anbutsu, Hisashi; Fukatsu, Takema

    2015-06-01

    Huanglongbing, or citrus greening, is a devastating disease of citrus plants recently spreading worldwide, which is caused by an uncultivable bacterial pathogen, "Candidatus Liberibacter asiaticus," and vectored by a phloem-sucking insect, Diaphorina citri. We investigated the infection density dynamics of "Ca. Liberibacter asiaticus" in field populations of D. citri with experiments using field-collected insects to address how "Ca. Liberibacter asiaticus" infection density in the vector insect is relevant to pathogen transmission to citrus plants. Of 500 insects continuously collected from "Ca. Liberibacter asiaticus"-infected citrus trees with pathological symptoms in the spring and autumn of 2009, 497 (99.4%) were "Ca. Liberibacter asiaticus" positive. The infections were systemic across head-thorax and abdomen, ranging from 10(3) to 10(7) bacteria per insect. In spring, the infection densities were low in March, at ∼ 10(3) bacteria per insect, increasing up to 10(6) to 10(7) bacteria per insect in April and May, and decreasing to 10(5) to 10(6) bacteria per insect in late May, whereas the infection densities were constantly ∼ 10(6) to 10(7) bacteria per insect in autumn. Statistical analysis suggested that several factors, such as insect sex, host trees, and collection dates, may be correlated with "Ca. Liberibacter asiaticus" infection densities in field D. citri populations. Inoculation experiments with citrus seedlings using field-collected "Ca. Liberibacter asiaticus"-infected insects suggested that (i) "Ca. Liberibacter asiaticus"-transmitting insects tend to exhibit higher infection densities than do nontransmitting insects, (ii) a threshold level (∼ 10(6) bacteria per insect) of "Ca. Liberibacter asiaticus" density in D. citri is required for successful transmission to citrus plants, and (iii) D. citri attaining the threshold infection level transmits "Ca. Liberibacter asiaticus" to citrus plants in a stochastic manner. These findings provide

  9. Evaluación de insecticidas para el control del psílido asiático de los cítricos (Diaphorina citri) Kuwayama (Hemíptera: Liviidae) en sus diferentes estados biológicos, en limón persa.

    OpenAIRE

    Ruíz Galván, Isabel

    2014-01-01

    Se evaluaron seis formulaciones comerciales de insecticidas para el control de los diferentes estados biológicos de Diaphorina citri (Kuwayama) en limón persa en condiciones de invernadero y en laboratorio. Los insecticidas estudiados fueron Imidacloprid + Betacyflutrin, Spirotetramat, Imidacloprid, Thiametoxam + Lambda cyalotrina, Imidacloprid + Lambda cyalotrina, Aceite parafínico de petróleo y un testigo sin aplicación. Se utilizaron especímenes de una cria de D. citri establecida en enero...

  10. Virulence of Beauveria bassiana CQBb111 Strain to Diaphorina citri and Neoseiulus cucumeirs%白僵菌CQBb111菌株对柑橘木虱和胡瓜新小绥螨的毒力差异

    Institute of Scientific and Technical Information of China (English)

    张艳璇; 孙莉; 林坚贞; 陈霞; 季洁

    2013-01-01

    Virulence of Beauveria bassiana CQBb111 strain at different concentration to the adults of Diaphorina citri and the female adults of Neoseiulus cucumeirs was evaluated in the laboratory. The corrected accumulative mortality caused by suspension liquid of 1.0×104 conidia·mL−1 against D. citri and N. cucumeir were 92.68%and 4.05%, respectively, 10 d after treatment. LC50 against D. citri and N. cucumeir were 2.24×109 and 5.4×1012 conidia·mL−1, respectively,at the 3rd d after treatment. At the same treatment time, concentration that caused 50%death of D. citri was only slightly virulent to N. cucumeir. LT50 against D. citri was 2.88 d at the concentration of 1.0×108 conidia·mL−1, but the corrected accumulative mortality of N. cucumeir was only 10.7% at 2.88 d. LT50 against D. citri was much smaller than thatagainst N. cucumeir at the same concentration of CQBb111 strain. The strain can achieve good control of adults of D. citri while exert slightly negative influence on female adults of N. cucumeir and it can be used in combination with N. cucumeir to control D. citri and huanglongbing vectored by D. citri.%  本文用球孢白僵菌 CQBb111菌株的分生孢子配成不同浓度的悬浮液对柑橘木虱成虫和胡瓜新小绥螨雌成螨的毒性进行了测定。1.0×104孢子·mL−1的悬浮液作用第10 d的柑橘木虱和胡瓜新小绥螨累计校正死亡率分别为92.68%、4.05%,同浓度的孢子悬浮液对柑橘木虱的致死率远高于其对胡瓜新小绥螨的致死率。柑橘木虱和胡瓜新小绥螨第3 d的LC50为2.24×109、5.4×1012孢子·mL−1,同一时间下,对柑橘木虱致死率达50%的悬浮液对胡瓜新小绥螨的影响甚微。浓度为1.0×108孢子·mL−1时,柑橘木虱的LT50为2.88 d,而胡瓜新小绥螨此时校正死亡率仅为10.7%,同浓度的孢子悬浮液对柑橘木虱的LT50远小于胡瓜新小绥螨的LT50。该菌株对柑橘木虱成虫有很好的防治效果而对胡瓜

  11. The monofunctional catalase KatE of Xanthomonas axonopodis pv. citri is required for full virulence in citrus plants.

    Directory of Open Access Journals (Sweden)

    María Laura Tondo

    Full Text Available BACKGROUND: Xanthomonas axonopodis pv. citri (Xac is an obligate aerobic phytopathogen constantly exposed to hydrogen peroxide produced by normal aerobic respiration and by the plant defense response during plant-pathogen interactions. Four putative catalase genes have been identified in silico in the Xac genome, designated as katE, catB, srpA (monofunctional catalases and katG (bifunctional catalase. METHODOLOGY/PRINCIPAL FINDINGS: Xac catalase activity was analyzed using native gel electrophoresis and semi-quantitative RT-PCR. We demonstrated that the catalase activity pattern was regulated in different growth stages displaying the highest levels during the stationary phase. KatE was the most active catalase in this phase of growth. At this stage cells were more resistant to hydrogen peroxide as was determined by the analysis of CFU after the exposition to different H(2O(2 concentrations. In addition, Xac exhibited an adaptive response to hydrogen peroxide, displaying higher levels of catalase activity and H(2O(2 resistance after treatment with sub-lethal concentrations of the oxidant. In the plant-like medium XVM2 the expression of KatE was strongly induced and in this medium Xac was more resistant to H(2O(2. A XackatE mutant strain was constructed by insertional mutagenesis. We observed that catalase induction in stationary phase was lost meanwhile the adaptive response to peroxide was maintained in this mutant. Finally, the XackatE strain was assayed in planta during host plant interaction rendering a less aggressive phenotype with a minor canker formation. CONCLUSIONS: Our results confirmed that in contrast to other Xanthomonas species, Xac catalase-specific activity is induced during the stationary phase of growth in parallel with the bacterial resistance to peroxide challenge. Moreover, Xac catalases expression pattern is modified in response to any stimuli associated with the plant or the microenvironment it provides. The catalase Kat

  12. Comparison of PCR,DIA and Pathogenicity Assay for Detection of Xanthomonas axonopodis pv.citri,the Causal Agent of Citrus Bacterial Canker Disease

    Institute of Scientific and Technical Information of China (English)

    WANG Zhong-kang; SUN Xian-yun; YIN You-ping; ZHOU Chang-yong; XIA Yu-xian

    2004-01-01

    Polymerase chain reaction (PCR) approach based on newly designed primers, JYF5/JYR5, was applied for specific detection of Xanthomonas axonopodis pv.citri(Xac). The efficiency and reliability of PCR method were compared with dot immunobinding assay (DIA) and classical pathogenicity test techniques for detecting suspensions of pure cells of Xac and soaking sap of citrus tissues. Detection sensitivity of PCR was about 4.5 cells or 1.56 pg target DNA per reaction which was higher than that of DIA (ca. 450 cells per dot).These three techniques (PCR assay, DIA and Pathogenecity test) could always detect Xac from symptomatic citrus samples. Different performances were obtained from citrus materials without symptoms, and the positive detection frequency was PCR, DIA and pathogenicity test.

  13. Xanthomonas axonopodis pv. citri YaeQ structure reveals new compact protein fold built around a variation of the PD-(D/E)XK nuclease motif

    Energy Technology Data Exchange (ETDEWEB)

    Guzzo, Cristiane Rodrigues; Farah, Chuck Shaker [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica. Dept. de Bioquimica; Nagem, Ronaldo Alves Pinto [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Inst. de Ciencias Biologicas. Dept. de Bioquimica e Imunologia; Barbosa, Joao Alexandre Ribeiro Goncalves [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil). Centro de Biologia Molecular Estrutural

    2008-11-15

    The YaeQ family of proteins derives from close to two hundred species of Gram-negative bacteria. Despite their widespread distribution, their molecular and physiological functions are unknown. We used X-ray crystallography and multi-wavelength anomalous dispersion to determine the high resolution structure of the YaeQ protein (XAC2398) from the phytopathogen Xanthomonas axonopodis pv. citri. The novel structure revealed that YaeQ pertains to the PD-(D/E)XK superfamily of metal-dependent endonucleases. The phylogenetic distribution of YaeQ proteins and a detailed comparison of the YaeQ structure with that of other PD-(D/E)XK family members point to specific testable hypotheses regarding YaeQ function. (author)

  14. Impacts of horticultural mineral oils and two insecticide practices on population fluctuation of Diaphorina citri and spread of Huanglongbing in a citrus orchard in Sarawak.

    Science.gov (United States)

    Leong, Stephen Chan Teck; Abang, Fatimah; Beattie, Andrew; Kueh, Roland Jui Heng; Wong, Sing King

    2012-01-01

    Aspects of the incidence and spread of the citrus disease huanglongbing (HLB) in relation to the vector Diaphorina citri population fluctuation were studied from January 1999 to December 2001 seasons in a 0.8 ha citrus orchard at Jemukan (1° 33'N, 110° 41'E), Southwest Sarawak in Malaysia. In relation to insecticide and horticultural mineral oils (HMOs) use, levels of HLB infection rose quite rapidly over the next 3 years in the unsprayed control and less rapidly in the other treatments such as imidacloprid, nC24HMO, and triazophos/cypermethrin/chlorpyrifos. Levels of HLB as determined by Polymerase Chain Reaction (PCR) were 42.2%, 9.4%, 11.4%, and 22.7%, respectively. The effects of nC(24)HMO and conventional pesticides on the citrus psyllid population and parasitoids in citrus orchard were also determined.

  15. Tests on the control of Panonychus citri (Megregor)with different pesticides%不同药剂防治桔全爪螨效果试验

    Institute of Scientific and Technical Information of China (English)

    钱开胜

    1996-01-01

    @@ 桔全爪螨Panonychus citri(Mc Gregor),又称柑桔红蜘蛛.在资源县一年发生12~14代,多以卵在叶片背部或枝干上越冬.本地区3~4月间持续阴雨天气,经常致使冬季清园不当的柑桔园全爪螨暴发;秋季高温过后,成螨从老叶大量转移至新叶,在有利条件下也易造成猖獗危害,为此,笔者在桔全爪螨暴发的柑桔园进行了药剂防治试验.

  16. Impacts of Horticultural Mineral Oils and Two Insecticide Practices on Population Fluctuation of Diaphorina citri and Spread of Huanglongbing in a Citrus Orchard in Sarawak

    Directory of Open Access Journals (Sweden)

    Stephen Chan Teck Leong

    2012-01-01

    Full Text Available Aspects of the incidence and spread of the citrus disease huanglongbing (HLB in relation to the vector Diaphorina citri population fluctuation were studied from January 1999 to December 2001 seasons in a 0.8 ha citrus orchard at Jemukan (1° 33′N, 110° 41′E, Southwest Sarawak in Malaysia. In relation to insecticide and horticultural mineral oils (HMOs use, levels of HLB infection rose quite rapidly over the next 3 years in the unsprayed control and less rapidly in the other treatments such as imidacloprid, nC24HMO, and triazophos/cypermethrin/chlorpyrifos. Levels of HLB as determined by Polymerase Chain Reaction (PCR were 42.2%, 9.4%, 11.4%, and 22.7%, respectively. The effects of nC24HMO and conventional pesticides on the citrus psyllid population and parasitoids in citrus orchard were also determined.

  17. Responses of the predatory mite Neoseiulus cucumeris to life stages and secretions of Diaphorina citri%柑橘木虱及分泌物对胡瓜新小绥螨的吸引作用研究

    Institute of Scientific and Technical Information of China (English)

    张艳璇; 孙莉; 林坚贞; 陈霞; 季洁

    2013-01-01

    Movements of the predatory mite Neoseiulus cucumeris (Oudemans) toward different life stages and secretions of Diaphorina citri Kuwayama were investigated an open environment, simulating natural conditions. The response of adult female N. cucumeris to different life stages of D. citri and to the secretions of D. citri on Murraya panicuata shoots was studied using choice tests at 25℃. The results were:1. Female N. cucumeris showed a significant response to mixed life stages of D. citri after two hours and a highly significant response after three hours, indicating that the response to mixed life stages of D. citri is very strong. 2. Female N. cucumersi were not attracted to D. citri eggs. 3. Hourly counts of the numbers of female N. cucumeris on shoots with young D. citri nymphs in the first five hours of the experiment were, 25. 00% ,18. 33% , 13. 33% , 15. 00% and 23. 33% higher, respectively, than those on control shoots without D. citri nymphs. 4. The response of predators to old D. citri nymphs was highest at the end of the first hour of the experiment and lowest during the second and third hours. The proportion of predators began to rebound during the fourth hour and had increased to 51. 67% by the end of fifth hour. This shows that old D. citri nymphs are attractive to N. cucumeris. 5. In trials using secretions of D. citri, the number of predators on shoots with secretions was 33. 33% higher than on control shoots, one hour after the start of the experiment. At the end of two hours, the proportion of predators departing the treatment shoot had increased but the number on treatment shoots remained higher than on control shoots. This result shows that females of N. cucumersi are attracted to secretions of D. citri.%在25℃温度条件下,在九里香(Murraya panicuata)嫩枝条上研究柑橘木虱Diaphorina citri Kuwayama混合虫态、卵、低龄若虫、高龄若虫、柑橘木虱分泌物对胡瓜新小绥螨Neoseiulus cucumeirs(Oudemans)雌螨的吸

  18. Nested-quantitative PCR approach with improved sensitivity for the detection of low titer levels of Candidatus Liberibacter asiaticus in the Asian citrus psyllid, Diaphorina citri Kuwayama.

    Science.gov (United States)

    Coy, M R; Hoffmann, M; Kingdom Gibbard, H N; Kuhns, E H; Pelz-Stelinski, K S; Stelinski, L L

    2014-07-01

    Candidatus Liberibacter asiaticus (CLas) is a phloem-limited bacterium transmitted by the Asian citrus psyllid, Diaphorina citri, and the presumptive causal agent of citrus greening disease. The current method of detection for CLas within plant and insect samples is by a presence/absence qPCR assay using the CLas 16S rDNA gene target. Although qPCR is highly sensitive, low bacterial titers or suboptimal qPCR conditions can result in false-negatives. Using a nested qPCR assay, we determined the false-negative rate of the 16S presence/absence qPCR assay was greater than 50%. Studies to determine the performance parameters of the qPCR assays for CLas 16S and Wingless (Wg), the D. citri endogenous gene, using plasmid and psyllid DNA, revealed suboptimal and variable performance of the 16S assay in psyllid samples. Average efficiencies and sensitivity limits of the plasmid assays were 99.0% and 2.7 copies of template for Wg, respectively, and 98.5% and 2.2-22.1 copies for 16S, respectively. Variability in efficiency was significantly greater in psyllid samples for both gene targets compared to the corresponding plasmid assays, and efficiencies as low as 76% were obtained for 16S. A secondary structure analysis revealed the formation of two stem-loop structures that block the forward and probe binding sites in the 16S template, which could hinder amplification. In summary, our results suggest that suboptimal qPCR efficiency is not uncommon for the 16S presence/absence qPCR assay, which combined with lowCLas titers in some samples, could contribute significantly to the under-reporting of CLas infection in psyllid and plant samples. PMID:24769405

  19. 柑橘木虱主要形态与成虫行为习性观察%Morphology and Behavior of Asian Citrus Psyllid, Diaphorina citri Kuwayama

    Institute of Scientific and Technical Information of China (English)

    阮传清; 陈建利; 刘波; 段永平; 夏育陆

    2012-01-01

    为了便于鉴别亚洲柑橘木虱(Diaphorina citri Kuwayama)的不同虫态和成虫性别,为繁殖和研究该木虱提供参考.利用Leica体视显微镜观察了该木虱各虫态的形态大小.结果表明:其卵、1~5龄若虫体长分别为(0.253±0.011)mm,(0.304±0.022) mm,(0.46±0.035) mm,(0.675±0.022) mm,(1.038 ±0.004) mm和(1.563±0.004) mm.在室内观察了柑橘木虱交配、产卵、取食、羽化等行为学特性,并绘制了柑橘木虱雌、雄成虫触角、足、翅膀和生殖器示意图.%To differentiate nymphs and sexes of the Citrus Asian Psyllids (ACP), Diaphorina citri Kuwayama, ACP in different life stages were examined for their morphological characteristics under Leica stereo microscopes. The examinations revealed that ACP eggs and 1st-5th instars nymphs were measured (0.253 ±0.011) mm, (0.304 ± 0.022) mm, (0.46 ± 0.035) mm, (0.675 ± 0.022) mm, (1.038 ± 0.004) mm, (1.563 ±0.004) mm in length, respectively. ACP adults were also characterized by figures in terms of their morphological characteristics. The adult behaviors of feeding, mating and oviposition were also described.

  20. Nested-quantitative PCR approach with improved sensitivity for the detection of low titer levels of Candidatus Liberibacter asiaticus in the Asian citrus psyllid, Diaphorina citri Kuwayama.

    Science.gov (United States)

    Coy, M R; Hoffmann, M; Kingdom Gibbard, H N; Kuhns, E H; Pelz-Stelinski, K S; Stelinski, L L

    2014-07-01

    Candidatus Liberibacter asiaticus (CLas) is a phloem-limited bacterium transmitted by the Asian citrus psyllid, Diaphorina citri, and the presumptive causal agent of citrus greening disease. The current method of detection for CLas within plant and insect samples is by a presence/absence qPCR assay using the CLas 16S rDNA gene target. Although qPCR is highly sensitive, low bacterial titers or suboptimal qPCR conditions can result in false-negatives. Using a nested qPCR assay, we determined the false-negative rate of the 16S presence/absence qPCR assay was greater than 50%. Studies to determine the performance parameters of the qPCR assays for CLas 16S and Wingless (Wg), the D. citri endogenous gene, using plasmid and psyllid DNA, revealed suboptimal and variable performance of the 16S assay in psyllid samples. Average efficiencies and sensitivity limits of the plasmid assays were 99.0% and 2.7 copies of template for Wg, respectively, and 98.5% and 2.2-22.1 copies for 16S, respectively. Variability in efficiency was significantly greater in psyllid samples for both gene targets compared to the corresponding plasmid assays, and efficiencies as low as 76% were obtained for 16S. A secondary structure analysis revealed the formation of two stem-loop structures that block the forward and probe binding sites in the 16S template, which could hinder amplification. In summary, our results suggest that suboptimal qPCR efficiency is not uncommon for the 16S presence/absence qPCR assay, which combined with lowCLas titers in some samples, could contribute significantly to the under-reporting of CLas infection in psyllid and plant samples.

  1. Development and experiment of Panonychus citri infestation fast detector%柑橘全爪螨虫害快速检测仪的研制与试验

    Institute of Scientific and Technical Information of China (English)

    李震; 洪添胜; 王建; 李楠; 孙道宗; 林瀚

    2014-01-01

    In order to achieve a rapid, accurate, non-destructive, in-situ detection of Panonychus citri (McGregor) infestation levels to the fruit trees, a Panonychus citri (McGregor) fast detector based on optical measurement techniques was designed and developed in this study. The instrument’s working effect was tested through experiments. The optical reflection method was adopted by the detector as the detection principle, and the tree canopy’s light reflectance in the red and near-infrared light zone was measured. The Panonychus citri (McGregor) index (PCI) was introduced in this study as the equipment output and was calculated in accordance with the measured reflectance. Furthermore, the Panonychus citri (McGregor) infestation status at a tree’s selected canopy outer area was divided into three levels as None, Light, and Heavy based on the number of eggs on top of the leaves within a specific region at the tree canopy’s outer area. The relationship between the infestation levels of the regions and their corresponding PCI readings was analyzed. In the hardware design, light emitting diode (LED) arrays having center wavelengths of 665nm and 815nm were selected as the red and near-infrared light sources. Natural light interference at the detector was mostly reduced by using a 40 kHz light modulation/demodulation technology, a specially designed optical path, and a photoelectric detection adapting circuit. Results from the instrument’s working effect test indicated that: the detection coefficient k equals to 2.622;the detection was less slightly affected by the foliage density;the detection was less affected by the natural environmental light, but was affected by the temperature to some extent; the three Panonychus citri (McGregor) infestation levels as None, Light and Heavy could be distinguished by the detector, and when the infestation level was low, the result was stable. High correlation was achieved between the detector’s PCI reading and the number of eggs

  2. All five host-range variants of Xanthomonas citri carry one pthA homolog with 17.5 repeats that determines pathogenicity on citrus, but none determine host-range variation.

    Science.gov (United States)

    Al-Saadi, Abdulwahid; Reddy, Joseph D; Duan, Yong P; Brunings, Asha M; Yuan, Qiaoping; Gabriel, Dean W

    2007-08-01

    Citrus canker disease is caused by five groups of Xanthomonas citri strains that are distinguished primarily by host range: three from Asia (A, A*, and A(w)) and two that form a phylogenetically distinct clade and originated in South America (B and C). Every X. citri strain carries multiple DNA fragments that hybridize with pthA, which is essential for the pathogenicity of wide-host-range X. citri group A strain 3213. DNA fragments that hybridized with pthA were cloned from a representative strain from all five groups. Each strain carried one and only one pthA homolog that functionally complemented a knockout mutation of pthA in 3213. Every complementing homolog was of identical size to pthA and carried 17.5 nearly identical, direct tandem repeats, including three new genes from narrow-host-range groups C (pthC), A(w) (pthAW), and A* (pthA*). Every noncomplementing paralog was of a different size; one of these was sequenced from group A* (pthA*-2) and was found to have an intact promoter and full-length reading frame but with 15.5 repeats. None of the complementing homologs nor any of the noncomplementing paralogs conferred avirulence to 3213 on grapefruit or suppressed avirulence of a group A* strain on grapefruit. A knockout mutation of pthC in a group C strain resulted in loss of pathogenicity on lime, but the strain was unaffected in ability to elicit an HR on grapefruit. This pthC- mutant was fully complemented by pthA, pthB, or pthC. Analysis of the predicted amino-acid sequences of all functional pthA homologs and nonfunctional paralogs indicated that the specific sequence of the 17th repeat may be essential for pathogenicity of X. citri on citrus. PMID:17722697

  3. 橘全爪螨有螨叶率防治指标的初步研究%Preliminary Study on the Controlling Index of the Leaf Incidence of Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    张志恒; 陈国庆; 陈亦根

    2000-01-01

    @@ 橘全爪螨(Panonychus citri Mcgregor)是为害柑橘的一种主要害虫,常因防治不及时而造成减产和品质下降.如何快速准确地实施虫情调查监测,适时指导药剂防治,是橘全爪螨综合治理的一个重要环节.

  4. 树干注射印楝素对柑橘全爪螨的控制作用%Effect of Trunk Injection of Azadirachtin on the Control of Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    曾兆华; 王玉林; 杨广

    2013-01-01

    The control effect of azadirachtin with trunk injection at 1 - 3 mg per cm DBH (diameter at breast height) was above 90% on Panonychus citri (McGregor) 7 days after injection in the field, and remained above 75% in 60 days. The sublethal doses of azadirachtin on different developmental stages of P. citri were determined and their long-term effects on P. citri population were discovered to be the extension of developmental duration and reduced fecundity.%开展树干注射印楝素对柑橘全爪螨的控制作用研究.结果表明,每厘米胸径树干注射1~3 mg印楝素在药后7d对柑橘全爪螨田间防治效果可达90%以上,持续至60 d仍可达75 %以上;测定内吸印楝素对各螨态柑橘全爪螨的亚致死剂量,发现其对柑橘全爪螨种群具有延长发育历期、降低繁殖力的长期控制效应.

  5. 湖南柑橘大实蝇对不同柑橘品种的危害特点研究初报%The Damage Characteristics of Tetradacus citri Chen on Different Citrus Varieties in Hunan Province

    Institute of Scientific and Technical Information of China (English)

    林文力; 杨水芝; 潘美山; 陈海玲; 黄泽培; 龙建国; 肖伏莲

    2011-01-01

    采用定点观察和普查的方式对湖南省吉首市、麻阳县柑橘大实蝇的危害特点进行了研究.结果表明:柑橘大实蝇对不同柑橘品种的危害时间由早到晚依次为:脐橙>温洲蜜柑>冰糖橙≥大红甜橙=广柑>椪柑;其危害最严重的品种是脐橙,虫果率达63%,其次是早熟温洲蜜柑和冰糖橙,达22%,再次是椪柑,达6%;同时还发现,柑橘不同品种果皮表面存在产卵假痕迹现象.这些结果可为柑橘大实蝇的防治提供理论参考依据.%The damage characteristics of Tetradacus citri Chen in Mayang County, Jishou City, Hunan Province were investigated by fixed-point observation method and general survey method. The results indicated that the harm time of Tetradacus citri Chen on different varieties of citrus ordered as navel orange>satsuma mandarin>Citrus sinensis ^Citrus sineasis Osbeck cv. Dahong= Citrussinensis (L.) Osbeck >Citrus reticulata Blanco cv. Ponkan; the damage level of Tetradacus citri Chen on different varieties of citrus ordered as navel orange>early mature satsuma mandarin and Citrus sinensis >dtrus reticulata Blanco cv. Ponkan, and the insect infestation ratio of navel orange, early mature satsuma mandarin, Citrus sinensis and Citrus reticulata Blanco cv. Ponkan was 63%, 22%, 22% and 6%, respectively. Meanwhile, the research also showed that there are fake oviposition traces of Tetradacus citri Chen on the Peels of different varieties of citrus. These results above can provide the theory basis for the control of Tetradacus citri Chen.

  6. Occurrence and control of citrus melanose caused by Diaporthe citri%柑橘黑点病的发病规律和防治

    Institute of Scientific and Technical Information of China (English)

    姜丽英; 徐法三; 黄振东; 黄峰; 陈国庆; 李红叶

    2012-01-01

    近年来,柑橘黑点病(Diaporthe citri)在浙江、江西等柑橘产区普遍发生,逐渐成为柑橘最主要病害之一,严重影响鲜销果实的外观品质和销售价格.2008年以来,通过对该病的症状、发生规律和防治技术开展研究发现,果实整个生长期都能感病,但以果实膨大期最感病;黑点病的严重度与树龄、施肥水平和杀菌剂的使用次数关系密切;以座果后每隔20d使用保护性杀菌剂代森锰锌防治效果较好,代森锰锌中添加0.25%~0.50%矿物油(绿颖)能有效地提高其防效.文章同时结合国内外相关研究,对黑点病症状、病原、发生规律和防治技术作了较为详尽的综述.%Melanose, caused by Diaporthe citri, has become a serious disease on citrus fruits in citrus-growing region of Zhejiang, Jiangxi provinces etc. It deteriorates exterior quality and brings down sale price of citrus fruits for fresh marketing. We have been involved in the investigation of the symptoms, prevalence and control methods of this disease since 2008. It was demonstrated that citrus fruits are susceptible to this disease in whole developmental stage, and especially susceptible during the enlarging stage. The order of melanose severity was closely associated with citrus age, times of fertilization and fungicide application. The best control efficiency could be obtained by application of protective fungicides such as mancozeb (followed the instruction of manufactory) 20 days interval after fruit-setting. Superior efficiency would be even achieved when 0. 25% to 0. 5% mineral oil ( SK spray oil) was mixed with mancozeb. Inter- and intranational information regarding the symptoms, characteristics of pathogen, epidemic factors and disease control of melanose was elaborately integrated in this paper.

  7. 橘全爪螨种群空间分布与危害%Population Spacial Distribution and Harm of Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    甘宗义; 朱红艳; 潭荣荣

    2012-01-01

    The spacial distribution pattern, population dynamics and harm of Panonychus citri McG on citrus tree were studied by test of theoretical distribution and analysis of spacial pattern indexes. The results showed that the population distribution of the mite suits with Negative-binomial distribution in citrus garden, and fits with Neyman distribution-A in lower population density too. The spacial distribution pattern presents loose colonies, in which distribution of the colonies is aggregated and the individuals in the colonies show random distribution. The aggregation intensity of population distribution is changing with changes in the mite population density. The aggregation in low density population is caused by environmental factors; and in highdeasity population it is concerned with their biological activities. When the population density a certain up to a certain harm grade, the spacial volume reaching and outstripping this harm level is not over 30% of the total space in citrus garden, accordingly, the area sprayed with insecticides for controlling the harmful mite should not be over 30% of all the area in the field.%通过理论分布的适合性检验、空间格局指标分析,对橘全爪螨(Panonychus citri McG)在温州蜜柑上的空间分布特征、动态与危害进行了系统研究.结果表明,橘全爪螨田间种群分布符合负二项分布,低密度下偶尔符合Neyman A分布.空间分布的基本成分为疏松的个体群,个体群内成员间的分布为随机分布,个体群间呈聚集分布,聚集强度随种群密度的变化而变化,种群低密度下的聚集主要由环境因素引起,高密度下的聚集与该螨自身生物学特性有关.当田间种群数量达到某一危害级别时,相应级别的危害空间容积不超过总体空间的30%,相应的田间药剂防治面积也不应超过总面积的30%.

  8. 亚洲柑橘木虱的刺吸电位图谱研究%Study on the Electrical Penetration Graph of Diaphorina citri

    Institute of Scientific and Technical Information of China (English)

    杨成良; 岑伊静; 梁广文; 陈华燕

    2011-01-01

    The stylet penetration activities of Diaphorina citri Kuwayama on seedlings of Citrus reticulata Blanco (Rutaceae) were investigated by using the electrical penetration graph (EPG-DC system) technique,and the relationship between the feeding behavior and the waveforms was analysed. Eight EPG waveforms were described for adult female D. citrifeeding on C. reticulata leaves during 8 hours: Non-penetration waveform (waveform np), pathway waveforms (waveform A, B and C ), first contact with phloem (waveform D), saliva secretion on phloem (waveform E 1 ), phloem sap ingestion (waveform E2 ), and xylem sap ingestion (waveform G). Among these, waveform D, which always occurred between waveform C and waveform El ,was firstly found in insect with piercing mouthparts. Waveform G only occurred on 3 of the 20 tested psyllids, implying the psyllids seldom feed in the xylem. Waveform E2 lasted longest, indicating the psyllids spent the most of time in phloem sap ingestion during the feeding activity.%利用刺吸电位图谱(EPG)技术对亚洲柑橘木虱Diaphorina citri Kuwayama在寄主植物酸橙Citrus reticulata Blanco上的刺探取食行为进行了测定,获得柑橘木虱取食出现的波形,初步确定了取食波形与其行为之间的关系.结果表明,亚洲柑橘木虱在酸橙上产生8种主要的取食波形,依次为非刺探波(np波)、路径波(A波、B波、C波)、D波、韧皮部分泌唾液波(E1波)、韧皮部被动吸食波(E2波)以及木质部主动吸食波(G波).其中,D波是首次发现在刺吸式口器昆虫的取食波,推测为柑橘木虱口针刺探筛管相关的波形.G波仅在所测定20头木虱中的3头上出现,说明木虱很少在木质部吸食.E2波持续时间最长,表明刺探过程中木虱口针在韧皮部吸食的时间最长.

  9. Aspectos biológicos de Chrysoperla externa (Hagen, 1861(Neuroptera: Chrysopidae alimentada com Planococcus citri (Risso, 1813(Hemiptera: Pseudococcidae e Toxoptera citricida (Kirkaldy, 1907 (Hemiptera: Aphididae Bipogical aspects of Chrysoperla externa (Hagen, 1861 (Neuroptera: Chrysopidae fed with Planococcus citri (Risso, 1813 (Hemiptera: Pseudococcidae and Toxoptera citricida (Kirkaldy, 1907 (Hemiptera: Aphididae (Hemiptera: Aphididae

    Directory of Open Access Journals (Sweden)

    Jean Patrick Bonani

    2009-02-01

    Full Text Available O ecossistema citrícola abriga muitas espécies de inimigos naturais, entre eles Chrysoperla externa (Hagen, 1861 que apresenta um grande potencial como agente de controle biológico de pragas. Neste trabalho, objetivou-se avapar o efeito das presas Planococcus citri (Risso, 1813 e Toxoptera citricida (Kirkaldy, 1907 sobre o desenvolvimento das fases de larva e pupa de C. externa. O ensaio foi conduzido em sala cpmatizada a uma temperatura de 25±1ºC, 70±10% UR e fotofase de 12 horas, sendo os tratamentos constituídos pelo fornecimento contínuo e alternado dessas duas presas em cada ínstar do predador, além de ovos de Anagasta kuehniella (Zeller, 1879, utilizados para fins de comparação. Foram avaliados o tempo de vida e a viabilidade das fases de larva, pupa e do período larva-adulto de C. externa. Constatou-se que T. citricida fornecido isoladamente ao longo do desenvolvimento larval ou em dois ínstares consecutivos do predador, não foi uma presa adequada, constatando-se 100% de mortalidade no período larva-adulto. Quando as larvas alimentaram-se de P. citri fornecida em dois ínstares do predador, a viabilidade no período larva-adulto foi semelhante à dieta constituída por apenas ovos de A. kuehniella, exceto quando se alimentaram de T. citricida no primeiro ínstar.The citrus-growing ecosystem houses a great deal of species of natural enemies, among them Chrysoperla externa (Hagen, 1861, which presents a great potential for use in the bipogical contrp of pests. The aim of this work was to evaluate the effects of the preys Planococcus citri (Risso, 1813 and Toxoptera citricida (Kirkaldy, 1907 on the development of larva and pupa of C. externa. The trial was carried out in an accpmatized room at 25±1ºC, 70±10% RH and 12-hour photophase, the treatments consisting of the continuous and alternate supply of those two preys in each instar of the predator, in apition to eggs of Anagasta kuehniella (Zeller, 1879 utilized for

  10. The Field Efficacy Trials of Chlorfenapyr 10% SC on Diaphorina Citri Kuwayama and Phyllocnistis Citrella Stainton and Other Citrus Pests%10%虫螨腈SC防治柑桔木虱、潜叶蛾等四种柑桔害虫田间药效试验

    Institute of Scientific and Technical Information of China (English)

    邓明学; 覃旭; 谭有龙; 翟高云; 甘光耀; 蒋建军; 蓝冰团; 韦巍

    2011-01-01

    BACKGROUND: The field efficacy trials on chlorfenapyr 10% SC had been conducted out to validate the control effect against Asian Citrus Psylla(Diaphorina citri Kuwayama), Phyllocnistis citrella Stainton, Dialeurodes citri Ashmeadand Panonychus citri McGregor in August to October in 2010. RESULTS: The results of field trials showed that the efficacies of 3, 7 days after treatment of chlorfenapyr 10% SC against Phyllocnistis citreUa were all 100% at 500, 667 mg/L and 97.9% and 92.1% at 1000 mg/L. The efficacies were 83.2% and 25.1% after 1, 3 days treatment against Dialeurodes citri at 1000 mg/L. The efficacies against adult of Asian Citrus Psylla were 95.1% to 99.8% during 1 to 15 days after treatment at 667, 1000 mg/L.The efficacies against Panonychus citri were 63.2% to 90.9% during 2 to 15 days after treatment at 500, 667, 1000 mg/L. CONCLUSIONS: Chlorfenapyr 10% SC provided good efficacy against Phyllocnistis citrella, Asian Citrus Psylla and Panonychus cirri and quick-acting and short persistent effect against Dialeurodes citri.%对10%虫螨腈SC进行防治柑桔木虱、潜叶蛾等四种柑桔害虫田间药效试验。结果表明,10%虫螨腈SC对柑桔木虱、潜叶蛾防效好;对柑桔粉虱速效性较好,但持效性差;对柑桔红蜘蛛的防效一般,特别是速效性差。

  11. Simultaneous determination of six bioactive flavonoids in Citri Reticulatae Pericarpium by rapid resolution liquid chromatography coupled with triple quadrupole electrospray tandem mass spectrometry.

    Science.gov (United States)

    Liu, E-Hu; Zhao, Pan; Duan, Li; Zheng, Guo-Dong; Guo, Long; Yang, Hua; Li, Ping

    2013-12-15

    A rapid resolution liquid chromatography/electrospray ionisation tandem mass spectrometry (RRLC-ESI-MS(n)) method has been firstly developed and validated for simultaneous determination of six bioactive flavonoids in Citri Reticulatae Pericarpium (CRP). The antiproliferative activities of the six flavonoids in CRP, namely naringin, hesperidin, nobiletin, 3,5,6,7,8,3',4'-heptamethoxyflavone, tangeretin and 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone, were evaluated and compared by Cell Counting Kit-8 Assay. Quantification was carried out on an Agilent triple quadrupole LC-MS system using multiple reaction monitoring mode. The established method was successfully applied for determination of the six flavonoids in samples collected from different regions in China. Compared with the reported analytical methods, the RRLC-ESI-MS(n) method is powerful in quantitative analysis of multi-component in terms of time savings and sensitivity. Hierarchical cluster analysis (HCA) was also performed to differentiate and classify the samples based on the contents of the six characteristic flavonoids. The HCA results indicated that Citrus reticulata 'Chachi' samples could be easily distinguished from other CRP samples. The developed RRLC-ESI-MS(n) method combined with HCA might be utilised as a quality control method for CRP. PMID:23993574

  12. Characterization of Chemical Composition of Pericarpium Citri Reticulatae Volatile Oil by Comprehensive Two-Dimensional Gas Chromatography with High-Resolution Time-of-Flight Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Kunming Qin

    2013-01-01

    Full Text Available Pericarpium Citri Reticulatae (Chenpi in Chinese has been widely used as an herbal medicine in Korea, China, and Japan. Chenpi extracts are used to treat indigestion and inflammatory syndromes of the respiratory tract such as bronchitis and asthma. This thesis will analyze chemical compositions of Chenpi volatile oil, which was performed by comprehensive two-dimensional gas chromatography with high-resolution time-of-flight mass spectrometry (GC × GC-HR-TOFMS. One hundred and sixty-seven components were tentatively identified, and terpene compounds are the main components of Chenpi volatile oil, a significant larger number than in previous studies. The majority of the eluted compounds, which were identified, were well separated as a result of high-resolution capability of the GC × GC method, which significantly reduces, the coelution. β-Elemene is tentatively qualified by means of GC × GC in tandem with high-resolution TOFMS detection, which plays an important role in enhancing the effects of many anticancer drugs and in reducing the side effects of chemotherapy. This study suggests that GC × GC-HR-TOFMS is suitable for routine characterization of chemical composition of volatile oil in herbal medicines.

  13. Repellent Activity of Extracts of Wild Rice Species against Panonychus citri and Aphis citricola in Associated with Esterase Isoenzyme in Insests

    Institute of Scientific and Technical Information of China (English)

    WAN Shu-qing; LIU Xiang-fa; FENG Guo-zhong; PAN Da-jian

    2006-01-01

    Six species of wild rice with different ecophenotypes including Oryza grandiglumis (E6-1, E6-3 / 6-4), O. minuta (E13-9,E13-13), O. officinalis (E15-8, E15-13), O. punctata (E16-1, E16-3, E1 6-13), O. granulata (E7-4), and O. latifolia (101392, E9-1, E9-10)were extracted with methnol and the repellent activity of the extracts against the two insects Aphis citricola and Panonychus citri were studied. The extracts of O. officinalis E15-8 showed higher repellent rate to the two insects than those of the other species. The repellent rates of the extracts of E15-8 to P. citriand A. citricola were 83.26% and 87.86% at 5×104 μg/mL in 24 h and 87.95% and 82.43% in 48 h, respectively. The extracts of O. officinalis E15-8 had the effect of inhibition to the esterase of the two insects.

  14. Detection of citrus huanglongbing-associated 'Candidatus Liberibacter asiaticus' in citrus and Diaphorina citri in Pakistan, seasonal variability, and implications for disease management.

    Science.gov (United States)

    Razi, Muhammad F; Keremane, Manjunath L; Ramadugu, Chandrika; Roose, Mikeal; Khan, Iqrar A; Lee, Richard F

    2014-03-01

    We report the detection of the huanglongbing (HLB)-associated bacterium 'Candidatus Liberibacter asiaticus' from both plants and insects in Pakistan and the seasonal variability in the numbers of 'Ca. L. asiaticus'-positive psyllid vector, Diaphorina citri. Our studies showed that 'Ca. L. asiaticus' was detectable from trees in areas with maximum temperatures reaching nearly 50°C (average maximum of 42°C). However, the bacterium was present at very low levels in psyllids both in summer (June to August) and autumn (September to November) in contrast to reports from Florida, where the bacterium was detectable at very high levels during October to November. We hypothesize that hot summer temperatures in Pakistan may interfere with acquisition and replication of 'Ca. L. asiaticus' in psyllids and may lead to dead or non transmissible 'Ca. L. asiaticus' in plants. Psyllid counts were very low in both summer and winter, showed a population peak ('Ca. L. asiaticus'-positive vectors) in spring, and showed a larger peak ('Ca. L. asiaticus'-free psyllids) in autumn. Natural thermotherapy during hot summers and a low vector population during environmental extremes may have played a major role in long-term survival of the citrus industry in Pakistan. These results may be useful in developing management strategies for U.S. citrus industries in Texas and California.

  15. Detection of citrus huanglongbing-associated 'Candidatus Liberibacter asiaticus' in citrus and Diaphorina citri in Pakistan, seasonal variability, and implications for disease management.

    Science.gov (United States)

    Razi, Muhammad F; Keremane, Manjunath L; Ramadugu, Chandrika; Roose, Mikeal; Khan, Iqrar A; Lee, Richard F

    2014-03-01

    We report the detection of the huanglongbing (HLB)-associated bacterium 'Candidatus Liberibacter asiaticus' from both plants and insects in Pakistan and the seasonal variability in the numbers of 'Ca. L. asiaticus'-positive psyllid vector, Diaphorina citri. Our studies showed that 'Ca. L. asiaticus' was detectable from trees in areas with maximum temperatures reaching nearly 50°C (average maximum of 42°C). However, the bacterium was present at very low levels in psyllids both in summer (June to August) and autumn (September to November) in contrast to reports from Florida, where the bacterium was detectable at very high levels during October to November. We hypothesize that hot summer temperatures in Pakistan may interfere with acquisition and replication of 'Ca. L. asiaticus' in psyllids and may lead to dead or non transmissible 'Ca. L. asiaticus' in plants. Psyllid counts were very low in both summer and winter, showed a population peak ('Ca. L. asiaticus'-positive vectors) in spring, and showed a larger peak ('Ca. L. asiaticus'-free psyllids) in autumn. Natural thermotherapy during hot summers and a low vector population during environmental extremes may have played a major role in long-term survival of the citrus industry in Pakistan. These results may be useful in developing management strategies for U.S. citrus industries in Texas and California. PMID:24134720

  16. The filamentous phage XacF1 causes loss of virulence in Xanthomonas axonopodis pv. citri, the causative agent of citrus canker disease

    Directory of Open Access Journals (Sweden)

    Abdelmonim Ali Ahmad

    2014-07-01

    Full Text Available In this study, filamentous phage XacF1, which can infect Xanthomonas axonopodis pv. citri (Xac strains, was isolated and characterized. Electron microscopy showed that XacF1 is a member of the family Inoviridae and is about 1000 nm long and 16 nm in width. The genome of XacF1 is 7325 nucleotides in size, containing 13 predicted open reading frames (ORFs, some of which showed significant homology to Ff-like phage proteins such as ORF1 (pII, ORF2 (pV, ORF6 (pIII, and ORF8 (pVI. XacF1 showed a relatively wide host range, infecting seven out of 11 strains tested in this study. Frequently, XacF1 was found to be integrated into the genome of Xac strains. This integration occurred at the host dif site (attB and was mediated by the host XerC/D recombination system. The attP sequence was identical to that of Xanthomonas phage Cf1c. Interestingly, infection by XacF1 phage caused several physiological changes to the bacterial host cells, including lower levels of extracellular polysaccharide production, reduced motility, slower growth rate, and a dramatic reduction in virulence. In particular, the reduction in virulence suggested possible utilization of XacF1 as a biological control agent against citrus canker disease.

  17. Toxicity of bifenazate and its principal active metabolite, diazene, to Tetranychus urticae and Panonychus citri and their relative toxicity to the predaceous mites, Phytoseiulus persimilis and Neoseiulus californicus.

    Science.gov (United States)

    Ochiai, Noriaki; Mizuno, Masayuki; Mimori, Norihiko; Miyake, Toshihiko; Dekeyser, Mark; Canlas, Liza Jara; Takeda, Makio

    2007-01-01

    Bifenazate is a novel carbazate acaricide discovered by Uniroyal Chemical (now Chemtura Corporation) for the control of phytophagous mites infesting agricultural and ornamental crops. Its acaricidal activity and that of its principal active metabolite, diazene, were characterized. Bifenazate and diazene had high toxicity and specificity both orally and topically to all life stages of Tetranychus urticae and Panonychus citri. Acute poisoning was observed with no temperature dependency. No cross-resistance was found to mites resistant to several other classes of acaricides, such as tebufenpyrad, etoxazole, fenbutatin oxide and dicofol. Bifenazate remained effective for a long time with only about a 10% loss of efficacy on T. urticae after 1 month of application in the field. All stages of development of the predatory mites, Phytoseiulus persimilis and Neoseiulus californicus, survived treatment by both bifenazate and diazene. When adult females of the two predatory mite species were treated with either bifenazate or diazene, they showed a normal level of fecundity and predatory activity in the laboratory, effectively suppressing spider mite population growth. Even when the predators were fed spider mite eggs that had been treated previously with bifenazate, they survived. These findings indicate that bifenazate is a very useful acaricide giving high efficacy, long-lasting activity and excellent selectivity for spider mites. It is, therefore, concluded that bifenazate is an ideal compound for controlling these pest mites. PMID:17972019

  18. Evaluation of suitable reference genes for quantitative RT-PCR during development and abiotic stress in Panonychus citri (McGregor) (Acari: Tetranychidae).

    Science.gov (United States)

    Niu, Jin-Zhi; Dou, Wei; Ding, Tian-Bo; Yang, Li-Hong; Shen, Guang-Mao; Wang, Jin-Jun

    2012-05-01

    Quantitative real time reverse transcriptase polymerase chain reaction (RT-qPCR) is preferred for gene expression analysis in living organisms. Currently, it is a valuable tool for biological and ecological studies as it provides a relatively straightforward way to assess the relevance of transcriptional regulation under developmental and stress tolerance conditions. However, studies have shown that some commonly used reference genes varied among different experimental treatments, thus, systematic evaluation of reference genes is critical for gene expression profiling, which is often neglected in gene expression studies of arthropods. The aim of this study is to identify the suitable reference genes for RT-qPCR experiments involving various developmental stages and/or under abiotic stresses in citrus red mite Panonychus citri, a key pest in citrus orchards worldwide. GeNorm, NormFinder, and Bestkeeper software analysis indicates that elongation factor-1 alpha (ELF1A), RNA polymerase II largest subunit, alpha tublin, and glyceraldhyde-3-phosphate dehydrogenase (GAPDH) are the most stable reference genes in various developmental stages, meanwhile, ELF1A and GAPDH were the most stable reference genes under various abiotic stresses. Furthermore, this study will serve as a resource to screen reference genes for gene expression studies in any other spider mite species. PMID:22203483

  19. Novel insights into the genomic basis of citrus canker based on the genome sequences of two strains of Xanthomonas fuscans subsp. aurantifolii

    Directory of Open Access Journals (Sweden)

    Nociti Letícia A

    2010-04-01

    Full Text Available Abstract Background Citrus canker is a disease that has severe economic impact on the citrus industry worldwide. There are three types of canker, called A, B, and C. The three types have different phenotypes and affect different citrus species. The causative agent for type A is Xanthomonas citri subsp. citri, whose genome sequence was made available in 2002. Xanthomonas fuscans subsp. aurantifolii strain B causes canker B and Xanthomonas fuscans subsp. aurantifolii strain C causes canker C. Results We have sequenced the genomes of strains B and C to draft status. We have compared their genomic content to X. citri subsp. citri and to other Xanthomonas genomes, with special emphasis on type III secreted effector repertoires. In addition to pthA, already known to be present in all three citrus canker strains, two additional effector genes, xopE3 and xopAI, are also present in all three strains and are both located on the same putative genomic island. These two effector genes, along with one other effector-like gene in the same region, are thus good candidates for being pathogenicity factors on citrus. Numerous gene content differences also exist between the three cankers strains, which can be correlated with their different virulence and host range. Particular attention was placed on the analysis of genes involved in biofilm formation and quorum sensing, type IV secretion, flagellum synthesis and motility, lipopolysacharide synthesis, and on the gene xacPNP, which codes for a natriuretic protein. Conclusion We have uncovered numerous commonalities and differences in gene content between the genomes of the pathogenic agents causing citrus canker A, B, and C and other Xanthomonas genomes. Molecular genetics can now be employed to determine the role of these genes in plant-microbe interactions. The gained knowledge will be instrumental for improving citrus canker control.

  20. Advances in Biological Control of Citrus Psyllid Diaphorina citri, a Vector Insect of Citrus Huanglongbing Disease%黄龙病媒介昆虫柑橘木虱生物防治新进展

    Institute of Scientific and Technical Information of China (English)

    代晓彦; 任素丽; 周雅婷; 任顺祥; 邱宝利

    2014-01-01

    The citrus psyllid, Diaphorina citri Kuwayama, is the primary vector of citrus Huanglongbing disease, Candidatus Liberibacter asiaticus, which has the huge potential threats to the development of citrus industry in China. Based on the comprehensive understanding of D. citri control technologies, we reviewed the latest advances in biological control of D. citri and forecasted its future prospects. The main biological control resources of citrus psyllid currently are natural enemy insects and entomopathogenic fungi, among which predatory ladybeetles, lacewings, spiders and hover flies are the dominant species of predator, while Tamarixia radiata and Diaphorencyrtus aligarhensis are the two dominant parasitoids in China. Several representative entomopathogenic fungi include Lecanicillium lecanii, Isaria fumosorosea, Beauveria bassiana and Hirsutella citriformis have been reported with high virulence to citrus psyllid. This current review is expected to provide technical support and theoretical reference for efficient and sustainable control of citrus psyllid in the future.%柑橘木虱Diaphorina citri Kuwayama是柑橘黄龙病的重要媒介昆虫,对我国柑橘产业的健康发展潜在着巨大的威胁。本文在综合国内柑橘木虱防控技术的基础上,对近年来柑橘木虱生物防治的最新研究进展进行了综述,并且对其生物防治的发展前景给予了展望。目前应用于柑橘木虱生物防治的天敌资源主要是天敌昆虫及昆虫病原真菌,其中捕食性天敌主要包括瓢虫、食蚜蝇、草蛉和蜘蛛,寄生性天敌昆虫主要包括啮小蜂和跳小峰;昆虫病原真菌主要包括蜡蚧轮枝菌、拟青霉、白僵菌、桔形被毛孢等。期望通过对柑橘木虱生物防治工作的综述,为我国今后柑橘木虱的科学、高效防控及其可持续治理提供参考,不断推动我国柑橘产业的健康发展。

  1. STUDIES ON INTERACTON OF CITRUS RED MITE PANONYCHUS CITRI(McG)POPULATION AND CITRUS%桔全爪螨与柑桔相互作用的研究

    Institute of Scientific and Technical Information of China (English)

    刘映红; 李隆术; 赵志模

    1995-01-01

    研究了不同柑桔品种对桔全爪螨Panonychus citri(McG)种群的影响,桔全爪螨危害对柑桔生理的影响以及柑桔叶片受害后对桔全爪螨种群的反馈作用.结果表明:供试的10个柑桔品种对桔全爪螨种群生长发育、繁殖有明显的影响,品种问存在感螨性差异.

  2. Studies on Growth and Decline Law and Chemical Control of Panonychus citri in Lemon Orchard in Ruili%瑞丽柠檬园红蜘蛛消长规律及药剂防治研究

    Institute of Scientific and Technical Information of China (English)

    王自然; 段惠芬; 彭满秀; 郭俊; 赵俊; 潘黎; 高俊燕

    2014-01-01

    The growth and decline law and chemical control of Panonychus citri in lemon orchard are studied in Ruili city , Yunnan province .The results indicate that Panonychus citri occurs mainly from November to the next January , and its population density reaches a peak (2500~3000 heads per plant) in middle January;the occurrence quantity of this mite is more in the north and south of lemon crown;the occurrence and damage of Panonychus citri in lemon orchard are closely related with temperature , hu-midity, food, fertilization, chemical control and so on;among the tested 7 kinds of pesticides, 4%Spirodiclofen SC, 1.8%Abam-ectin EC and 73%Propargite EC have better control effects on Panonychus citri, and they are safe and harmless to the young shoots , flowers and young fruits of lemon .%在云南省瑞丽市进行了柠檬园红蜘蛛的消长规律及药剂防治研究。结果表明:柠檬红蜘蛛主要在11月至次年1月发生,其发生量在1月中旬达到高峰(2500~3000头/株);红蜘蛛在树冠北方、南方的发生量较多;柠檬园红蜘蛛的发生和为害与温度、湿度、食料、施肥、施药等因素关系密切;在7种供试药剂中,以4%螺螨酯悬浮剂、1.8%阿维菌素乳油和73%炔螨特乳油对红蜘蛛的防治效果较好,且对柠檬的嫩梢、花和幼果安全无害。

  3. Evaluación de un Detergente en Base a Benceno Sulfonato de Sodio para el Control de la Mosquita Blanca Aleurothrixus floccosus (Maskell) (Hemiptera: Aleyrodidae) y de la arañita Roja Panonychus citri (McGregor) (Acarina: Tetranychidae) en Naranjos y Mandarinos Evaluation of a Detergent Based on Sodium Benzene Sulfonate for the Control of Woolly Whitefly Aleurothrixus floccosus (Maskell) (Hemiptera: Aleyrodidae) and Red Citrus Red Mites Panonychus citri (McGregor) (Acarina: Tetranychidae) on Oranges and Mandarins

    OpenAIRE

    Renato Ripa S; Fernando Rodríguez A.; Pilar Larral D; Robert  F Luck

    2006-01-01

    La mosquita blanca Aleurothrixus floccosus (Maskell) y la arañita roja Panonychus citri (McGregor) son consideradas plagas que causan daños económicos a los cítricos, y el uso de insecticidas no selectivos aumenta el problema por su efecto sobre los enemigos naturales. Para evaluar el uso del detergente en base a benceno sulfonato de sodio en la reducción de mosquitas blancas, arañitas y sus enemigos naturales se desarrollaron experimentos en dos huertos de cítricos. El primer ensayo fue real...

  4. 柑橘木虱对柑橘不同品种的趋性%Diaphorina citri's Gost Preference on Thirteen Citrus Varieties

    Institute of Scientific and Technical Information of China (English)

    陈建利; 阮传清; 刘波; 范国成; 段永平; D.HALL

    2011-01-01

    用2种方法测定了柑橘木虱Diaphorina citri Kuw.成虫对13个柑橘品种离体嫩梢的选择性.结果表明,对不同品种进行两两组合的选择性试验,柑橘木虱停靠在处理组合早金和四季斑叶橘的虫量占总虫量的23%和1%,停靠在处理组合台湾玫瑰橙和纽荷尔脐橙上的虫量分别占总虫量的33%和20%,停靠在处理组合日辉和佩奇甜橙上虫量分别占总虫量的38%和15%,两两之间差异显著.将13个品种组合在一起进行选择性试验,结果表明柑橘木虱停靠在纽荷尔、福橘和佩奇甜橙上的成虫数量为每梢3.2~6.6只·d-1,显著高于木虱在其余10个品种枝梢上的停靠数量.福橘是柑橘黄龙病高发品种的原因是其对柑橘木虱的吸引力较强.%Under laboratory conditions, preference of adult Asian Citrus Psyllid (ACP), Diaphorina citri Kuw, for infestation among 13 citrus varieties was determined with two experimentations. Experiment A applied every 2 detached shoots of different citrus varieties and put together for choice. Experiment B used the detached shoots of all tested citrus varieties and put together for choice. The results of Experiment A revealed that the percentage of ACP adults on each shoot of Citrus sinensis (L.) Osbeck cv. Earlygold and C. medurensis (C. mitis) cv. Varigated Calamondin were 23 % and 1 %, respectively, which was significantly different from each other. The percentage on C. sinensis Osbeck cv. Taiwanmeiguicheng (33%) and cv. Newhall Navel Orange (20%) were also significantly different from each other. Significant different percentages of ACP adults were also observed between C. reticulata C. paradisi cv. Rihui (38%) and C. reticulata C. grandis cv. Page (15%). In Experiment B, the number of ACP on the shoots of C. sinensis Osbeck cv. Newhall Navel Orange, C. tangerina Tanaka cv. Fuju and C. reticulata Citrusgrandis cv. Page was 3.2-6.6 adults · shoot-day-1 , which were significantly higher than that

  5. Temporal changes in color in Diaphorina citri%亚洲柑桔木虱体色变化规律的研究

    Institute of Scientific and Technical Information of China (English)

    吴丰年; 梁广文; 岑伊静; 高娃

    2013-01-01

    Change in the color of 5th instar nymphs and the abdomens and the forewings of adult Diaphorina citri Kuwayama were studied.Adult color was observed immediately after emergence,3 hours after emergence,and during the peak mating period and peak oviposition period.The influence of season,host plant and population density on adult color in males and females was also investigated.The results show that forewing color in both females and males followed a sequence of white to black to red brown after emergence.The abdomen color of females changed from olivine to grayish white to blue to orange,whereas that of males changed from olivine to dark gray to orange.The proportions of females with different colored abdomens varied seasonally and with host plant and population density,but that of males did not.The main abdomen color of females was blue or orange,whereas most males abdomens were orange,followed by dark gray.The color of 5th instar nymphs also changed as they got older.The sex ratios under different conditions were approximately 1:1,but there were fewer females than males in spring and autumn.%亚洲柑桔木虱Diaphorina citri Kuwayama为黄龙病的媒介昆虫.本文研究了其雌雄成虫在刚羽化、羽化后3 h、交配盛期和产卵盛期的腹部和前翅颜色变化规律,明确了每个时期的主要体色,同时探讨了不同季节、虫口密度和寄主条件对体色变化的影响.结果表明,雌雄木虱羽化后前翅颜色均由白色→黑色→红褐色渐变,木虱雌成虫腹部颜色随时间推移由黄绿色→灰白色→蓝色→橙色渐变,雄虫由黄绿色→灰黑色→橙色渐变.季节、寄主和虫口密度的变化对雌虫腹部颜色构成有一定的影响,但对雄虫基本上没有影响.不同条件下雌虫腹部的主要颜色为蓝色或橙色,雄虫均以橙色为主,其次为灰黑色,表明木虱成虫多处于交配期或产卵期.木虱5龄若虫的体色变化也较大.多数条

  6. Stylet morphometrics and citrus leaf vein structure in relation to feeding behavior of the Asian citrus psyllid Diaphorina citri, vector of citrus huanglongbing bacterium.

    Science.gov (United States)

    Ammar, El-Desouky; Hall, David G; Shatters, Robert G

    2013-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae), is the primary vector of the phloem-limited bacterium Candidatus Liberibacter asiaticus (LAS) associated with huanglongbing (HLB, citrus greening), considered the world's most serious disease of citrus. Stylet morphometrics of ACP nymphs and adults were studied in relation to citrus vein structure and to their putative (histologically verified) feeding sites on Valencia orange leaves. ACP nymphs preferred to settle and feed on the lower (abaxial) side of young leaves either on secondary veins or on the sides of the midrib, whereas adults preferred to settle and feed on the upper (adaxial) or lower secondary veins of young or old leaves. Early instar nymphs can reach and probe the phloem probably because the distance to the phloem is considerably shorter in younger than in mature leaves, and is shorter from the sides of the midrib compared to that from the center. Additionally, the thick-walled 'fibrous ring' (sclerenchyma) around the phloem, which may act as a barrier to ACP stylet penetration into the phloem, is more prominent in older than in younger leaves and in the center than on the sides of the midrib. The majority (80-90%) of the salivary sheath termini produced by ACP nymphs and adults that reached a vascular bundle were associated with the phloem, whereas only 10-20% were associated with xylem vessels. Ultrastructural studies on ACP stylets and LAS-infected leaves suggested that the width of the maxillary food canal in first instar nymphs is wide enough for LAS bacteria to traverse during food ingestion (and LAS acquisition). However, the width of the maxillary salivary canal in these nymphs may not be wide enough to accommodate LAS bacteria during salivation (and LAS inoculation) into host plants. This may explain the inability of early instar nymphs to transmit LAS/HLB in earlier reports.

  7. Behavioral, ultrastructural and chemical studies on the honeydew and waxy secretions by nymphs and adults of the Asian citrus psyllid Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Ammar, El-Desouky; Alessandro, Rocco; Shatters, Robert G; Hall, David G

    2013-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae) is the primary vector of the bacterium causing citrus huanglongbing (citrus greening), the most serious disease of citrus worldwide. Psyllids and other hemipterans produce large amounts of honeydew, which has been used previously as an indicator of phloem sap composition and insect feeding or metabolism. Behavioral, ultrastructural and chemical studies on ACP, its honeydew and waxy secretions showed important differences between nymphs, males and females, and suggested some mechanisms by which the psyllids, especially nymphs and adult females, can minimize their contamination with honeydew excretions. The anal opening in ACP, near the posterior end of the abdomen, is on the ventral side in nymphs and on the dorsal side in adult males and females. Video recordings showed that adult males produce clear sticky droplets of honeydew gently deposited behind their body on the leaf surface, whereas adult females produce whitish honeydew pellets powerfully propelled away from the female body, probably to get their excretions away from eggs and newly hatched nymphs. ACP nymphs produce long ribbons or tubes of honeydew that frequently stay attached to the exuviae after molting, or drop when feeding on the lower side of citrus leaves. Furthermore, honeydew excretions of both nymphs and adult females are covered with a thin layer of whitish waxy material ultrastructurally composed of a convoluted network of long fine filaments or ribbons. This material is extruded from intricate arrays of wax pores in the circumanal ring (around the anus) that is found in nymphs and females but not in males of ACP or other psyllid species. Infrared microscopy and mass spectroscopy revealed that, in addition to various sugars, honeydew excretions of ACP nymphs and females are covered with a thin layer of wax similar in profile to ester waxes. PMID:23762268

  8. Effect of temperature on life history and population growth parameters of Planococcus citri (Homoptera, Pseudococcidae on coleus [Solenostemon scutellarioides (L. Codd.

    Directory of Open Access Journals (Sweden)

    Goldasteh Shila

    2009-01-01

    Full Text Available The development, life history, reproduction, and population growth parameters of Planococcus citri Risso on coleus [Solenostemon scutellarioides (L. Codd.] were studied at various temperatures ranging from 10 to 37ºC, 70±10% RH, and photoperiod length of 16: 8 h (L: D. Females and males successfully developed into adults at from 15 to 32ºC and 18 to 32ºC, respectively. All first instars died at 10, 12, and 37ºC. Lower temperatures (10, 12, and 15ºC caused higher egg mortality than did higher temperatures (32, 35, and 37ºC. At all temperatures (except 15ºC, the highest percentage of nymphal mortality was observed in the first instar. The sex ratio was female-biased between 15 and 30ºC, but there was a slightly higher number of males at 32ºC. The highest adult longevities of females and males were obtained at 18 and 25°C, respectively. The pre-oviposition, oviposition, and post-oviposition periods were significantly different at various temperatures. The highest fecundity was observed at 23ºC. The shortest and longest oviposition periods occurred at 32 and 18ºC, respectively. Maximum values of the intrinsic rate of natural increase (rm, net reproduction rate (R0, and finite rate of increase (λ and the shortest mean generation time (T and doubling time (DT were obtained at 25ºC. Our findings showed citrus mealybug performances to be highly affected by temperature.

  9. Stylet morphometrics and citrus leaf vein structure in relation to feeding behavior of the Asian citrus psyllid Diaphorina citri, vector of citrus huanglongbing bacterium.

    Directory of Open Access Journals (Sweden)

    El-Desouky Ammar

    Full Text Available The Asian citrus psyllid (ACP, Diaphorina citri (Hemiptera: Psyllidae, is the primary vector of the phloem-limited bacterium Candidatus Liberibacter asiaticus (LAS associated with huanglongbing (HLB, citrus greening, considered the world's most serious disease of citrus. Stylet morphometrics of ACP nymphs and adults were studied in relation to citrus vein structure and to their putative (histologically verified feeding sites on Valencia orange leaves. ACP nymphs preferred to settle and feed on the lower (abaxial side of young leaves either on secondary veins or on the sides of the midrib, whereas adults preferred to settle and feed on the upper (adaxial or lower secondary veins of young or old leaves. Early instar nymphs can reach and probe the phloem probably because the distance to the phloem is considerably shorter in younger than in mature leaves, and is shorter from the sides of the midrib compared to that from the center. Additionally, the thick-walled 'fibrous ring' (sclerenchyma around the phloem, which may act as a barrier to ACP stylet penetration into the phloem, is more prominent in older than in younger leaves and in the center than on the sides of the midrib. The majority (80-90% of the salivary sheath termini produced by ACP nymphs and adults that reached a vascular bundle were associated with the phloem, whereas only 10-20% were associated with xylem vessels. Ultrastructural studies on ACP stylets and LAS-infected leaves suggested that the width of the maxillary food canal in first instar nymphs is wide enough for LAS bacteria to traverse during food ingestion (and LAS acquisition. However, the width of the maxillary salivary canal in these nymphs may not be wide enough to accommodate LAS bacteria during salivation (and LAS inoculation into host plants. This may explain the inability of early instar nymphs to transmit LAS/HLB in earlier reports.

  10. Behavioral, ultrastructural and chemical studies on the honeydew and waxy secretions by nymphs and adults of the Asian citrus psyllid Diaphorina citri (Hemiptera: Psyllidae.

    Directory of Open Access Journals (Sweden)

    El-Desouky Ammar

    Full Text Available The Asian citrus psyllid (ACP, Diaphorina citri (Hemiptera: Psyllidae is the primary vector of the bacterium causing citrus huanglongbing (citrus greening, the most serious disease of citrus worldwide. Psyllids and other hemipterans produce large amounts of honeydew, which has been used previously as an indicator of phloem sap composition and insect feeding or metabolism. Behavioral, ultrastructural and chemical studies on ACP, its honeydew and waxy secretions showed important differences between nymphs, males and females, and suggested some mechanisms by which the psyllids, especially nymphs and adult females, can minimize their contamination with honeydew excretions. The anal opening in ACP, near the posterior end of the abdomen, is on the ventral side in nymphs and on the dorsal side in adult males and females. Video recordings showed that adult males produce clear sticky droplets of honeydew gently deposited behind their body on the leaf surface, whereas adult females produce whitish honeydew pellets powerfully propelled away from the female body, probably to get their excretions away from eggs and newly hatched nymphs. ACP nymphs produce long ribbons or tubes of honeydew that frequently stay attached to the exuviae after molting, or drop when feeding on the lower side of citrus leaves. Furthermore, honeydew excretions of both nymphs and adult females are covered with a thin layer of whitish waxy material ultrastructurally composed of a convoluted network of long fine filaments or ribbons. This material is extruded from intricate arrays of wax pores in the circumanal ring (around the anus that is found in nymphs and females but not in males of ACP or other psyllid species. Infrared microscopy and mass spectroscopy revealed that, in addition to various sugars, honeydew excretions of ACP nymphs and females are covered with a thin layer of wax similar in profile to ester waxes.

  11. Population Dynamics and Dispersal of Asian Citrus Psyllid Diaphorina citri Kuwayama%柑桔木虱种群动态与扩散的调查研究

    Institute of Scientific and Technical Information of China (English)

    张林锋; 赵金鹏; 曾鑫年

    2012-01-01

    柑桔木虱(Diaphorina citri Kuwayam.)是传播柑桔毁灭性病害——柑桔黄龙病(hunglongbing,HLB)的媒介昆虫,为探明田间柑桔木虱种群发生与扩散规律.利用柑桔木虱分布北沿地区冬天低温致死、春天升温扩散条件,2010—2011年调查了广东省乐昌市柑桔木虱的种群动态和田间扩散情况.结果表明:有少量柑桔木虱成虫在乐昌中南部越冬,3月底开始产卵,6—10月种群数量迅速增长,至10月中旬柑桔木虱成虫密度达最高峰;5月初首次监测到柑桔木虱种群向北扩散,扩散距离为5km,至6月中旬再向北扩散,扩散距离2.5 km,但扩散的成虫数量不多.相关性分析表明,田间柑桔木虱种群密度与田间温度、嫩梢数量呈极显著的正相关,而与相对湿度无显著相关;田间柑桔木虱的扩散与日平均温度、日最大温度、日最小温度呈极显著正相关,而与日相对湿度、日平均风速无显著相关.

  12. Behavioral, ultrastructural and chemical studies on the honeydew and waxy secretions by nymphs and adults of the Asian citrus psyllid Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Ammar, El-Desouky; Alessandro, Rocco; Shatters, Robert G; Hall, David G

    2013-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae) is the primary vector of the bacterium causing citrus huanglongbing (citrus greening), the most serious disease of citrus worldwide. Psyllids and other hemipterans produce large amounts of honeydew, which has been used previously as an indicator of phloem sap composition and insect feeding or metabolism. Behavioral, ultrastructural and chemical studies on ACP, its honeydew and waxy secretions showed important differences between nymphs, males and females, and suggested some mechanisms by which the psyllids, especially nymphs and adult females, can minimize their contamination with honeydew excretions. The anal opening in ACP, near the posterior end of the abdomen, is on the ventral side in nymphs and on the dorsal side in adult males and females. Video recordings showed that adult males produce clear sticky droplets of honeydew gently deposited behind their body on the leaf surface, whereas adult females produce whitish honeydew pellets powerfully propelled away from the female body, probably to get their excretions away from eggs and newly hatched nymphs. ACP nymphs produce long ribbons or tubes of honeydew that frequently stay attached to the exuviae after molting, or drop when feeding on the lower side of citrus leaves. Furthermore, honeydew excretions of both nymphs and adult females are covered with a thin layer of whitish waxy material ultrastructurally composed of a convoluted network of long fine filaments or ribbons. This material is extruded from intricate arrays of wax pores in the circumanal ring (around the anus) that is found in nymphs and females but not in males of ACP or other psyllid species. Infrared microscopy and mass spectroscopy revealed that, in addition to various sugars, honeydew excretions of ACP nymphs and females are covered with a thin layer of wax similar in profile to ester waxes.

  13. A plant natriuretic peptide-like molecule of the pathogen Xanthomonas axonopodis pv. citri causes rapid changes in the proteome of its citrus host

    Directory of Open Access Journals (Sweden)

    Ottado Jorgelina

    2010-03-01

    Full Text Available Abstract Background Plant natriuretic peptides (PNPs belong to a novel class of peptidic signaling molecules that share some structural similarity to the N-terminal domain of expansins and affect physiological processes such as water and ion homeostasis at nano-molar concentrations. The citrus pathogen Xanthomonas axonopodis pv. citri possesses a PNP-like peptide (XacPNP uniquely present in this bacteria. Previously we observed that the expression of XacPNP is induced upon infection and that lesions produced in leaves infected with a XacPNP deletion mutant were more necrotic and lead to earlier bacterial cell death, suggesting that the plant-like bacterial PNP enables the plant pathogen to modify host responses in order to create conditions favorable to its own survival. Results Here we measured chlorophyll fluorescence parameters and water potential of citrus leaves infiltrated with recombinant purified XacPNP and demonstrate that the peptide improves the physiological conditions of the tissue. Importantly, the proteomic analysis revealed that these responses are mirrored by rapid changes in the host proteome that include the up-regulation of Rubisco activase, ATP synthase CF1 α subunit, maturase K, and α- and β-tubulin. Conclusions We demonstrate that XacPNP induces changes in host photosynthesis at the level of protein expression and in photosynthetic efficiency in particular. Our findings suggest that the biotrophic pathogen can use the plant-like hormone to modulate the host cellular environment and in particular host metabolism and that such modulations weaken host defence.

  14. A plant natriuretic peptide-like molecule of the pathogen Xanthomonas axonopodis pv. citri causes rapid changes in the proteome of its citrus host

    KAUST Repository

    Garavaglia, Betiana S

    2010-03-21

    Background: Plant natriuretic peptides (PNPs) belong to a novel class of peptidic signaling molecules that share some structural similarity to the N-terminal domain of expansins and affect physiological processes such as water and ion homeostasis at nano-molar concentrations. The citrus pathogen Xanthomonas axonopodis pv. citri possesses a PNP-like peptide (XacPNP) uniquely present in this bacteria. Previously we observed that the expression of XacPNP is induced upon infection and that lesions produced in leaves infected with a XacPNP deletion mutant were more necrotic and lead to earlier bacterial cell death, suggesting that the plant-like bacterial PNP enables the plant pathogen to modify host responses in order to create conditions favorable to its own survival.Results: Here we measured chlorophyll fluorescence parameters and water potential of citrus leaves infiltrated with recombinant purified XacPNP and demonstrate that the peptide improves the physiological conditions of the tissue. Importantly, the proteomic analysis revealed that these responses are mirrored by rapid changes in the host proteome that include the up-regulation of Rubisco activase, ATP synthase CF1 ? subunit, maturase K, and ?- and ?-tubulin.Conclusions: We demonstrate that XacPNP induces changes in host photosynthesis at the level of protein expression and in photosynthetic efficiency in particular. Our findings suggest that the biotrophic pathogen can use the plant-like hormone to modulate the host cellular environment and in particular host metabolism and that such modulations weaken host defence. 2010 Garavaglia et al; licensee BioMed Central Ltd.

  15. Bioactivity of Several Bactericides against Xanthomonas campestris pv.citri%几种杀菌剂对柑桔溃疡病的生物活性

    Institute of Scientific and Technical Information of China (English)

    孙惠敏; 李保同; 郭明程; 陈慈相; 谢金招; 刘德力

    2011-01-01

    为筛选防治柑桔溃疡病的有效药剂,按大田推荐使用浓度,用抑菌圈法测定17种非铜药剂和5种含铜药剂对柑桔溃疡病的毒力,并研究7种非铜药剂田间防治效果.结果表明,代森锰锌、福美双、福美双·溴菌腈、农用链霉素、金核霉素和琥胶肥酸铜·乙磷铝·硫酸锌抑菌作用最强,其次为福美双·福美锌、大蒜素、络氨铜·络氨锌和盐酸吗啉胍·乙酸铜,过氧乙酸、噻唑锌、春雷菌素、中生菌素、琥珀酸铜和噻菌铜有微弱的抑菌作用,百菌清、多菌灵、苯醚甲环唑、叶青双、复硝酚钠和井冈霉素无抑菌作用.大田试验结果表明,30%金核霉素WP 500 mg/L和72%农用链霉素WP 200 mg/L处理对柑桔溃病的防效分别为76.34%和74.94%,显著优于其它药剂处理;80%代森锰锌WP 2000 mg/L、50%福美双WP 400 mg/L和50%福美双·溴菌腈WP 500 mg/L处理对柑桔溃病的防效分别为70.36%、66.55%和69.37%,与对照含铜药剂20%噻菌铜SC 67 mg/L处理无显著差异;大蒜素和叶青双对柑桔溃病防效较差,6%大蒜素EC 120 mg/L和20%叶青双WP 400 mg/L处理对柑桔溃病的防效分别为41.84%和21.82%,显著低于对照含铜药剂20%噻菌铜SC 67 mg/L处理.%In order to screen effective bactericides against Xanthomonas camprestris pv. citri, the toxicity of 17 non - copper fungicides and 5 copper fungicides against the strain of X. campestris pv. citri in the greenhouse were determined by the method of inhibition zone, and the efficacy of 7 non - copper fungicides in the field was tested. The results showed that manzoceb, thiram, thiram -bromothalonil, agricultural streptomycin, aureonucleomycin and DT -fosetyl -aluminium -zinc suffate had the strongest inhibitory effect on the pathogen, thiram- ziram, allicin, cupric tetramminosuffate- zinc tetramminosuffate and moroxydine hydrochloride- cupric acetate had relatively strong inhibitory effect, peracetic acid, Zn thiazole, Kasugamycin, Zhong

  16. Rapid screening and identification of compounds with DNA-binding activity from Folium Citri Reticulatae using on-line HPLC-DAD-MS(n) coupled with a post column fluorescence detection system.

    Science.gov (United States)

    Fu, Qingrong; Zhang, Cangman; Lin, Zongtao; Sun, Hongyang; Liang, Yi; Jiang, Haixiu; Song, Zhiling; Wang, Hong; Chen, Shizhong

    2016-02-01

    To study the interactions between natural compounds and deoxyribonucleic acid (DNA), a method has been established combining a high-performance liquid chromatography-diode array detector-multi-stage mass spectrometer with a fluorescence detector (HPLC-DAD-MS(n)-FLD). The FLD was used to monitor fluorescence intensity of the ethidium bromide-DNA (EB-DNA) complex when a compound separated by HPLC was introduced. This novel method was used to simultaneously obtain the HPLC fingerprint, UV spectra, MS(n) fragments and DNA-binding activity profile of various components in Folium Citri Reticulatae. As a result, 35 compounds were identified, of which 25 were found in the extract of Folium Citri Reticulatae for the first time, and 33 compounds showed DNA-binding activities, with the most active being feruloylhexaric and p-coumaroylhexaric acids. In addition, the precision, stability and reproducibility of this method were validated by two positive controls, quercetin and hesperidin. This new on-line method is accurate, precise and reliable for further high-throughput screening of DNA-binding compounds from food samples and other complex matrices.

  17. 我国柑橘木虱潜在适生区分布及趋势分析%Studies of the past, current and future potential distributions of Diaphorina citri Kuwayama (Homoptera:Psyllidae) in China

    Institute of Scientific and Technical Information of China (English)

    汪善勤; 肖云丽; 张宏宇

    2015-01-01

    【目的】柑橘木虱 Diaphorina citri Kuwayama 是传播黄龙病的重要虫媒,给柑橘生产带来极大危害。本文通过已知柑橘木虱发生地信息和40年气象数据求取准确的生物气候模型参数,在此基础上分析我国柑橘木虱潜在适生区分布变化和未来发展趋势。【方法】本文从1970年以来公开发表的文献中整理提取了柑橘木虱在我国1990年前后的发生地信息,分别基于 CLIMEX 的标准气象数据和国家气象局发布的1991—2010年的气象数据,得到能够准确预测柑橘木虱潜在适生区分布的 CLIMEX 参数。然后使用CliMond 发布的2030和2050年的全球气象数据,预测了未来柑橘木虱在我国的潜在适生区。【结果】2010年后柑橘木虱适生区分布北移明显,与实际发生地信息相吻合;全球气候变暖趋势影响下,2030年柑橘木虱适生区继续向北方扩展,但到2050年的适生区北界基本稳定,相比较而言临界区北移更加突出。【结论】柑橘木虱适生区北移明显,在未来气候条件下,干胁迫将阻止其进一步北移;但在临界气候条件下有建立种群的可能,对于目前未见该虫发生报道的潜在适生区,应加强早期预警和检疫防控措施。%[Objectives] Dysphoria citri Kuwayama (Homoptera: Psyllidae), the vector of Huanglongbing (Candidatus Liberobacter asiaticus), has caused major damage to China’s citrus industry. The objective of this paper is to (a) obtain optimal parameters for a CLIMEX model for D. citri, and (b) to investigate the past, current and future potential distributions of D. citri in China. [Methods] Information on the range of D. citri before and after 1990 in China were derived from the literature published since 1970. The parameters of a CLIMEX model were adjusted to fit these data and the species potential future range was estimated by the model. Two meteorological datasets, the CLIMEX integrated climate

  18. Study on Infrared Fingerprint of Exocarpium Citri Grandis with Different Species%化橘红药材红外指纹图谱的研究

    Institute of Scientific and Technical Information of China (English)

    卢丽萍; 林励; 黄爱华; 欧立娟; 汪金玉

    2011-01-01

    Objective To provide theoretical basis and practical methods for the rapid identification of Exocarpium Citri Grandis (ECG) with different species. Methods The fingerprints were established by fourier transform ifrared spectroscopy(FTIR), and then were analyzed by Spectrum v5.0.1 software. Results With normalization of the selected points between 1,820 cm-1 and 950 cm-1 on the FTIR fingerprints of ECG powder, significant differences were shown, and the second derivative spectra of the two different species between 1,800 cm-1 and 700 cm-1 had significant differences, which can be taken as one of the major identical characteristics to distinguish the two species. Conclusion The FTIR fingerprints is effective and feasible for the identification of the two species of ECG.%目的 建立化橘红药材的红外指纹图谱,通过考察不同品种化橘红药材的红外指纹图谱差异,为化橘红药材的快速鉴别提供理论依据和实用方法.方法 采用傅里叶红外光谱法(FTIR)建立不同品种化橘红药材红外指纹图谱,应用Spectrum v5.0.1红外软件对实验数据进行处理.结果 FTIR图谱在1820~950 cm-1范围内选点归一化处理后毛橘红和光橘红差异显著,其在1800~700 cm-1范围内二阶导数谱差异亦显著,可作为两者主要鉴别特征,经处理后的FTIR指纹图谱能有效鉴别两类化橘红药材.结论 红外指纹图谱法鉴别化橘红快速、简便、可行,可有效区分毛橘红和光橘红.

  19. 柑橘全爪螨对甲氰菊酯和阿维菌素的抗性选育及交互抗性%Resistance selection and cross-resistance of Panonychus citri to fenpropathrin and abamectin

    Institute of Scientific and Technical Information of China (English)

    何恒果; 王进军

    2015-01-01

    On the basis of resistance breeding and selection in laboratory,the resistance development of Panonych-us citri to fenpropathrin and abamectin was investigated and the cross-resistance of FeR and AbR to 1 1 acaricides was also studied.The results showed that,after 11-and 16-times of selection with abamectin and fenpropathrin,the re-sistance of P .citri to the two acaricides increased by 3.80-and 29.92-fold,respectively.Bioassay revealed that the cross-resistance of FeR to pyridaben,dicofol,azocyclotin and the cross-resistance of AbR to emamectin benzoate were very significant.The results provided references for the resistance management of P .citri to acaricides.%通过室内抗性品系选育,研究了柑橘全爪螨对甲氰菊酯和阿维菌素的抗性发展情况,并就其与柑橘园常用11种杀螨剂的交互抗性进行了分析。结果表明:在柑橘全爪螨19代中用甲氰菊酯和阿维菌素分别不连续汰选16次和11次后,柑橘全爪螨对两者的抗性分别为29.92和3.80倍;甲氰菊酯抗性品系(FeR)对哒螨灵、三氯杀螨醇和三唑锡产生了明显的交互抗性,阿维菌素抗性品系(AbR)对甲维盐产生了明显的交互抗性。试验结果可为柑橘全爪螨抗性治理提供参考。

  20. Aspectos biológicos da fase adulta de Chrysoperla externa (Hagen, 1861 (Neuroptera: Chrysopidae oriunda de larvas alimentadas com Planococcus citri (Risso, 1813 (Hemiptera: Pseudococcidae Biological aspects of the adult stage of Chrysoperla externa (Hagen, 1861 (Neuroptera: Chrysopidae originating from the larvae fed Planococcus citri (Risso, 1813 (Hemiptera: Pseudococcidae

    Directory of Open Access Journals (Sweden)

    Gerane Celly Dias Bezerra

    2006-08-01

    Full Text Available Objetivou-se estudar alguns aspectos biológicos da fase adulta de Chrysoperla externa (Hagen quando as larvas desse predador foram alimentadas com ninfas e fêmeas adultas de Planococcus citri (Risso. O experimento foi conduzido em câmara climatizada regulada a 25 ± 1 ºC, 70 ± 10% de UR e fotofase de 12 horas. Os adultos de C. externa cujas larvas foram alimentadas com ninfas nos três ínstares e fêmeas adultas da cochonilha, foram separados por sexo e 25 casais foram individualizados em gaiolas determinando-se a razão sexual, período de pré-oviposição, capacidade de oviposição diária e total durante 40 dias consecutivos, longevidade, período embrionário e viabilidade de ovos. Constatou-se que as ninfas nos três ínstares e fêmeas adultas fornecidas como alimento, não afetaram a razão sexual, período de pré-oviposição, período embrionário e longevidade dos adultos de C. externa. A produção diária e total de ovos por C. externa foi afetada pelo tipo de alimento fornecido ao predador durante a fase de larva, observando-se uma maior produção quando os casais foram alimentados na fase de larva com fêmeas adultas da cochonilha. Analisando-se a produção de ovos, observou-se uma maior concentração de oviposição nos primeiros dez dias do período reprodutivo, decrescendo nas avaliações seguintes. Foram obtidas porcentagens maiores de ovos viáveis e menores de inviáveis e inférteis, porém, não diferiram em função do alimento fornecido ao predador na fase de larva.It was aimed to study some biological aspects in the adult stage of Chrysoperla externa (Hagen when the larvae of predator were fed both nymphs and adult females of Planococcus citri (Risso. The experiment was conducted in climate chamber at 25 ± 1°C, 70 ± 10% of RH and 12-h photophase. The adults of C. externa whose larvae were fed nymphs at the three instars and adult females of mealybug were separated by sex and 25 couples were individualized

  1. Amostragem, caracterização de sintomas e escala diagramática da mancha graxa dos citros (Mycosphaerella citri no Recôncavo Baiano Sampling, characterization of citrus greasy spot (Mycosphaerella citri symptoms in Recôncavo Baiano and development of a diagrammatic scale for assessment of severity

    Directory of Open Access Journals (Sweden)

    Suely Xavier de Brito Silva

    2009-06-01

    Full Text Available O Recôncavo da Bahia é uma região de clima propício à mancha graxa dos citros (Mycosphaerella citri, doença nunca antes estudada no Brasil. Os objetivos deste trabalho foram definir o tamanho mínimo de amostra para quantificar a incidência, caracterizar os sintomas da doença e elaborar uma escala diagramática para a avaliação de sua severidade. A partir de uma amostragem piloto realizada por avaliação de cinco folhas por quadrante, quatro quadrantes por planta e 30 plantas em cada um dos 10 pomares visitados no município de Cruz das Almas, foi determinado que o tamanho mínimo da amostra em quadrantes e folhas seria de quatro e 16 plantas, respectivamente. De 320 folhas coletadas de diferentes plantas em 11 pomares, foi constatada uma grande quantidade de lesões (média de 131 por folha sintomática, em sua maioria diminutas (média de 0,014cm². A severidade variou de 0,15% a 35,85%, com média de 7,3%. Com base na severidade real em campo, foi elaborada uma escala diagramática com seis níveis: 1%, 2%, 5%, 9%, 18% e 36% de área foliar lesionada. Cinqüenta imagens de folhas foram submetidas a avaliadores por duas vezes, os quais estimaram a severidade com e sem a utilização da escala, constatando-se um discreto benefício no grau de precisão e de acurácia das estimativas com o uso da escala.Weather conditions make the Recôncavo Region in the State of Bahia, a favorable region to the occurrence of citrus greasy spot (Mycosphaerella citri, a disease that hadn't been studied before in Brazil. Thus, this research aimed to develop a sampling method to quantify its incidence, to characterize its symptoms, and to develop a diagrammatic scale for assessing disease severity. The minimum sample size to estimate greasy spot incidence in leaves (16 plants was calculated based on a prospective sampling of five leaves per quadrant, four quadrants per tree, and 30 trees per grove, in ten groves. From 320 mature leaves collected in

  2. Investigation on the resistance of different varieties of citrus to Xanthomonas citri%不同柑橘品种对柑橘溃疡病的抗性调查

    Institute of Scientific and Technical Information of China (English)

    宋盛英; 杨光兰; 潘盛勇; 赵春穆; 石安鸠

    2002-01-01

    通过柑橘Citrus sp.4类10个品种对柑橘溃疡病Xanthomonas citri(Hasse)Dowson抗病性的调查发现,不同的柑橘品种对柑橘溃疡病的抗病程度有明显差异,甜橙类、脐橙类普遍容易感病,属高度感病品种;宽皮橘类的抗病性最强;而柚类感病轻重不一,以台湾白柚抗病性最强,而沙田柚抗病性较弱.

  3. Selection and Biochemical Mechanism of the Resistance to Pyridaben in Panonychus citri%桔全爪螨对哒螨灵抗性的选育及其生化机理

    Institute of Scientific and Technical Information of China (English)

    孟和生; 王开运; 姜兴印; 仪美芹

    2000-01-01

    模拟田间药剂的选择压力,用哒螨灵对桔全爪螨(Panonychus citri McGregor)逐代处理,以选育其抗药性.结果表明:选育12代,抗性增长到35.0倍;哒螨灵抗性品系对氧乐果、双甲脒、氯氟氰菊酯、水胺硫磷和炔螨特有交互抗性.通过增效剂和离体酶活性测定证明:桔全爪螨对哒螨灵的抗性主要与谷胱甘肽S-转移酶、多功能氧化酶和乙酰胆碱酯酶活性的提高有关.

  4. 柑橘全爪螨微卫星位点鉴定与信息分析%Analysis of Microsatellite Loci fromPanonychus citri Based on Enriched Microsatellite Library and Transcriptome Dataset

    Institute of Scientific and Technical Information of China (English)

    魏丹丹; 刘燕; 杜洋; 李刚; 李婷; 袁明龙; 王进军

    2016-01-01

    重复类型,占总数的53.86%;其次为两碱基核心重复类型,占总数的43.36%;而四、五、六碱基重复类型以及复合型的SSR数量均较少,且数量差异不大,共占EST-SSR总数的2.78%。柑橘全爪螨EST-SSR核心重复次数主要集中在5—10次。【结论】采用磁珠富集法,并将酶切、接头连接一步化,可提高个体微小的螨类及微小昆虫SSR的富集效率。柑橘全爪螨gSSR核心重复次数要远多于从转录组数据库获得的EST-SSR。总体而言,gSSR和EST-SSR中的三碱基重复SSR具有更好的优化率。此外,柑橘全爪螨gSSR具有微卫星家族现象。%Objective] The objective of this study is to construct the microsatellite-enriched libraries, and identify genomic- microsatellite (gSSR) from the genome of the citrus red mite,Panonychus citri. Meanwhile, a large number of gene-microsatellite (EST-SSR) markers were also indentified from the transcriptome database ofP. citri. Based on these SSR sequences, the selected SSR primer pairs were validated.[Method]On the basis of isolating high quality genomic DNA ofP. citri, enriched microsatellite libraries were constructed by streptavidin-coated magnetic beads utilizing methodologies that exploit the strong affinity between biotin and the protein streptavidin. A fast and easy protocol was proposed through a combination of two different published methods. Briefly, genomic DNA was digested by the restriction enzyme and then ligated to designed adaptors. Microsatellite-containing DNA fragments were captured by streptavidin-coated magnetic beads. The beads affinity capture of microsatellite repeats using biotinylated oligonucleotide probes. Subsequently, PCR was used to amplify the captured molecules for transferring single strand DNA to double strand DNA. The PCR products were then ligated to pGEM-T Easy vector and transformed into Trans5α competent cells. Then, clones from these libraries were screened for microsatellite content. Meanwhile

  5. 柴油及其与阿维菌素复配对柑橘全爪螨卵的作用%Effect of Diesel Oil and its Mixture with Abamectin on the Eggs of Panonychus citri McGregor

    Institute of Scientific and Technical Information of China (English)

    熊忠华; 熊件妹; 罗丽

    2011-01-01

    室内测定了柴油对柑橘全爪螨卵的毒力及其与阿维菌素复配植物油基新型乳油的杀卵作用。结果表明,柴油对柑橘全爪螨卵的LC50为2790.39μg/mL;两种柴油与阿维菌素复配新型乳油1000、750和500倍液3种浓度下的杀卵率均高于90%,其中添加了印楝油的复配剂3浓度的杀卵率与对照药剂24%螺虫乙酯SC 3000倍液相当。%Toxicity of diesel oil against eggs of Panonychus citri and ovicidal action of diesel oil mixed with abamectin were determined in the lab.It was shown that,for the contact toxicity of diesel oil to eggs of Panonychus citri,the LC50 value was 2790.39 μg/mL.Besides,the ovicidal rate of two kinds of new type EC of abamectin-diesel oil combination were all above 90% treated with 1000,750 and 500 times diluted emulsion.Especially,the ovicidal rate of mixture at three concentration as above,which added neem oil,were as high as control pesticide of spirotetramat.So the new type EC of diesel oil mixed with abamectin had extensive application prospect in controlling pest mite.

  6. The controlling role of Panonychus citri by "Lümanyuan" in the filed and the measurement of its acute toxicity to Carassius auratus%“绿满园”对柑桔红蜘蛛的田间防治效果及对金鱼的毒性测定

    Institute of Scientific and Technical Information of China (English)

    乔虎平; 王金亮; 江庆红; 云月利; 王维; 彭宇

    2013-01-01

    测定“绿满园”水剂对柑桔红蜘蛛Panonychus citri的田间防治效果及对非靶标生物金鱼Carassius auratus 的急性毒性.结果表明,64%“绿满园”水剂800倍和1 000倍稀释液在施药后7d和15d对柑桔红蜘蛛的防治效果均极显著地高于对照杀螨剂:15%扫螨净和57%炔螨特,其中以800倍稀释液防治效果最好,15d的防效达97.21%,800倍和1 000倍稀释液的防治效果差异不明显.金鱼的死亡率随“绿满园”浓度的升高和染毒时间的延长逐渐增加.“绿满园”水剂对金鱼的急性毒性小于阿维菌素.%The controlling role of Panonychus citri by "Lumanyuan" in the filed and the measurement of its acute toxicity to Carassius auratus were carried out. The results showed that, 15 days after spraying, the controlling roles of 800 folds and 1 000 folds dilution of 64% "Lumanyuan" to P. citri was obviously higher than 15% pyridaben and 57% propargite. 800 fold dilution of "Lumanyuan" had the best controlling role to P. citri and the controlling effect was 97. 21%. There was no significant difference on controlling effects between 800 folds and 1 000 folds dilution of "Lumanyuan" to P. citri. The mortalities of C. auratus increased with the rise of the concentration and treatment time of "Lumanyuan" and "Lumanyuan" has lower acute toxicity to C. auratus than avermectin.

  7. Regular LAMP and fast LAMP for the detection of Xanthomonas axonopodis pv.citri%柑橘溃疡病菌的普通LAMP及快速LAMP检测方法的建立

    Institute of Scientific and Technical Information of China (English)

    张仑; 殷幼平; 吴瑜佳; 王中康

    2013-01-01

    This study is aimed to establish the regular LAMP and fast LAMP for the detection of Xanthomonas axonopodis pv.citri and make it useful for the grassroots quarantine departments.A specific region of the genome of X.axonopodis pv.citri was used for the design of regular LAMP and fast LAMP primers; the regular LAMP and fast LAMP detection system were established by optimization of reaction conditions; the specificity of the system was verified using genomic DNA of several reference strains and healthy citrus leaves by using a series of gradient dilution of DNA solution of X.axonopodis pv.citri and bacterial suspension.Bacterial suspension and DNA sensitivity of regular LAMP system reached 2.25 × 104 cfu and 2.03× 10-1 ng,respectively,while those of fast LAMP system reached 2.25 cfu and 2.03× 10-5 ng,respectively.In the specificity test,both regular LAMP and fast LAMP system showed high and identical specificity.The total time for the fast LAMP reaction was within 30 minutes,only half of that for the regular LAMP,greatly improving the efficiency of the analysis.The fast LAMP system was ten thousand times as sensitive as the regular LAMP system.Regular LAMP and fast LAMP for the detection of X.axonopodis pv.citri was successfully established.Regular LAMP and fast LAMP system provide a new,fast and easy way for the detection of X.axonopodis pv.citri.%建立柑橘溃疡病菌的普通LAMP和快速LAMP检测方法,使其能应用于基层检验检疫部门对病害的快速检测.利用柑橘溃疡病菌基因组特有的保守区域设计LAMP引物,通过优化反应条件,建立柑橘溃疡病菌的普通LAMP检测体系;在普通LAMP引物的基础上设计一对环引物,建立柑橘溃疡病菌的快速LAMP检测体系,并以多种参比菌DNA以及健康柑橘叶片基因组DNA为模板对普通LAMP和快速LAMP检测体系的特异性进行了验证,利用柑橘溃疡病菌菌液和DNA溶液梯度稀释液对普通LAMP和快速LAMP检测体系的灵敏度进

  8. Construction and evaluation of yeast two-hybrid cDNA library of Diaphorina citri (Hemiptera: Psyllidae)%柑橘木虱酵母双杂交cDNA文库的构建及评价

    Institute of Scientific and Technical Information of China (English)

    马晓芳; 陈国庆; 张学潮; 徐海君

    2013-01-01

    In order to study the interacting proteins between the Asian citrus psyllid ( Diaphorina citri) and Candidatus Liberibacter asiaticus ( CLas) which is the pathogenic bacterium causing Huanglongbing, yeast two-hybrid cDNA library of D. citri was constructed using the Switching Mechanism at 5' End of the RNA Transcript (SMART) technique. The total RNA was isolated from the citrus psyllid adults bred in the laboratory and subjected to reverse transcription, and the double-strand cDNAs ( ds cDNAs) were synthesized. The ds cDNAs were ligated with homologous adapter and purified by the chromatography column. By using homologous recombination reaction, the ds cDNAs were transformed into the Y187 competent cell with the library plasmid pGADT7-Rec to construct yeast two-hybrid cDNA library. Detection of the library indicated that it contained more than 106 independent clones, the titer of the amplified library was 2. 23 × 10 cfu/mL, and the average size of inserts was above 750 bp in the cDNA library. These results demonstrate that the library meets the requirements of the standard cDNA library. Moreover, two membrane proteins, ORF420 and ORF3420, from ( CLas) were used as bait proteins to screen the interacting proteins in the library, but no positive clone was screened in the tests. The yeast two-hybrid cDNA library of D. citri will be useful for the research on the interaction between insect vectors and C. Liberibacter asiaticus in the future.%为了探索研究柑橘木虱Diaphorina citri与柑橘黄龙病(Huanglongbing,HLB)病原菌的相互作用蛋白,本研究运用RNA转录中5 '末端转换机制(Switching Mechanism at 5'End of the RNA Transcript,SMART)技术构建了柑橘木虱的酵母双杂交cDNA文库.以实验室饲养的柑橘木虱为材料,提取总RNA,经反转录后合成ds cDNA,两端添加同源重组序列,并用层析柱纯化;ds cDNA与文库质粒pGADT7-Rec在酵母Y187感受态细胞内发生同源重组,柑橘木虱cDNA重组到文库质粒

  9. 柑橘全爪螨代谢抗性相关基因表达差异分析%Analysis of expression difference of metabolism genes in Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    冉春; 张云飞; 陈飞; 刘浩强; 李鸿筠; 胡军华; 姚廷山

    2013-01-01

    [Objective]To clarify the relationship among expression level of glutathione S-transferase (GST), Carboxylesterase (CarE), and Catalase (CAT) genes and resistance of P. citri, [Method]Resis-tance selection was conducted in laboratory and gene expression profiles of GST, CarE, and CAT gene between the resistant strain and susceptible strain were compared using Reads Per kb per Million reads (RPKM) method. [Result]After selection with hexythiazox continuously for 20 generations, a resistant strain was obtained with the resistance ratio (R/S) of 3532.12 compared with the susceptible strain. Analysis results of gene expression difference indicated that 11 GST genes, 17 CarE genes and 6 CAT genes were up-regulated, while 14 GST genes, 24 CarE genes and 3 CAT genes were down-regulated in resistant strain. Unigene31530[log2 ratio(RS/SS) =1.05], Unigene23121[log2 ratio(RS/SS) =2.05], and Uni-gene31477 [Iog2 ratio (RS/SS) = 10.04] were the top up-regulated GST gene, CarE gene and CAT gene, respectively. Further gene expression analysis using real-time PCR indicated that there was not significant difference in expression level of Unigene31477 between the resistant strain and susceptible strain. [Conclusion] Judging from gene expression differences between resistant and susceptible strains of P. citri, we concluded that up-regulation of GST, CarE and CAT genes may not play an important role in hexythiazox resistance of P. citri.%[目的]为了明确谷胱甘肽S-转移酶(GST)基因、羧酸酯酶(CarE)基因,过氧化氢酶(CAT)基因在柑橘全爪螨Panonychus citri抗性中的作用,[方法]在室内用噻螨酮对柑橘全爪螨进行抗性选育,进一步构建抗/敏品系数字基因表达谱,采用RPKM法对柑橘全爪螨敏感品系和噻螨酮抗性品系3种代谢抗性相关基因进行表达差异分析.[结果]经过20代抗性选育,获得了柑橘全爪螨噻螨酮抗性品系,与敏感品系比较,柑橘全爪螨对噻螨酮的抗性倍数达到3 532.12

  10. 不同防治措施对柑橘全爪螨及橘园天敌类群的影响%The effects of different control measures on Panonychus citri and arthropod enemies in citrus orchards

    Institute of Scientific and Technical Information of China (English)

    方小端; 欧阳革成; 卢慧林; 郭明防; 孟翔; 刘慧

    2013-01-01

    柑橘全爪螨Panonychus citri (McGregor)是柑橘上的重要有害生物,控制上目前仍以化学防治为主,捕食螨也在一些果园采用.安全性较高的农药正不断推广应用,一些生物源农药也已大面积使用.不过这些农药对柑橘全爪螨及其它柑橘害虫的田间控制效果如何,是否影响到商品捕食螨和果园自然天敌的种群维持与发展及其对柑橘害虫的持续控制,仍需较多而深入地检测和评估.2011年4-2012年1月,在广东省封开县,选择了3个不同害虫防治措施(以阿维菌素为主,巴氏新小绥螨Neoseiulus barkeri+矿物油乳剂为主,胡瓜新小绥螨N.cucumeris+苦参碱为主)的果园,调查比较了不同害虫防治措施对柑橘全爪螨的防治效果及对柑橘园中天敌类群的影响.试验结果显示,以巴氏新小绥螨+矿物油乳剂为主和以胡瓜新小绥螨+苦参碱为主的果园内自然天敌的丰富度高于以阿维菌素为主的果园,其群落结构也有所不同,它们对柑橘全爪螨和其它柑橘害虫的田间持续控制效果也比以阿维菌素为主的措施更好.%Panonychus citri (McGregor) is a major pest of citrus that is still controlled predominantly by chemical pesticides, although predatory mites are used in some orchards. Although safer chemical pesticides are now used in many citrus orchards there is a need to determine the effects of these pesticides on predatory mites and other natural enemies of P. citri. This experiment was carried out in citrus orchards in Fengkai County, Guangdong Province from April 2011 to January 2012. Three treatments were investigated: (1) Abamectin used as the main control agent; (2) Matrine used as the main control agent plus the predatory mite Neoseiulus cucumeris; ( 3 ) Mineral oil used as the main control agent plus the mite N. barkeri. The results show that the richness of natural enemy groups in citrus orchards controlled by Matrine + N. cucumeris and by Mineral oil + N

  11. Endosymbiont detection and phylogeny of Wolbachia in Diaphorina citri and Dialeurodes citri%华南地区柑橘木虱与柑橘粉虱内共生菌检测及其Wolbachia共生菌的系统发育关系分析

    Institute of Scientific and Technical Information of China (English)

    孙秀新; 师沛琼; 许炜明; 覃振强; 任顺祥; 邱宝利

    2016-01-01

    [Objectives] To survey the infection rates of different symbiotic bacteria in different geographic populations of the citrus psyllid and citrus whitefly, and to analyze the phylogenetic relationships between different Wolbachia populations in order to provide endosymbiont-based scientific support for the continuous management of the citrus psyllid and citrus whitefly. [Methods] Endosymbionts in citrus psyllids from Guangzhou, Zhanjiang, Xiamen, Guilin and Nanning, and citrus whiteflies from Guangzhou, were detected using PCR. The phylogenetic relationships of Wolbachia were analyzed using a phylogenetic tree constructed with MEGA 5.0 based on the Wolbachia wsp and MLST genes detected in citrus psyllids and citrus whiteflies. [Results] All citrus psyllid and whitefly populations in the current study were infected with the primary endosymbiont Portiera and the secondary endosymbionts Wolbachia, Cardinium, Rickettsia, but infection rates of these three endosymbionts varied between different geographical populations. Arsenophonus was only detectable in Guangzhou and Zhanjiang psyllid populations. Phylogenetic analysis revealed that Wolbachia endosymbionts in all citrus psyllid and whitefly populations were very similar and belonged to the Con group of the Wolbachia B supergroup. [Conclusion] The species and infection rates of endosymbionts varied among different geographical populations of the citrus psyllid and whitefly. There is no apparent coevolutionary relationship between Wolbachia and its psyllid hosts. Indeed, the high homology of Wolbachia in different hosts suggests plant-mediated horizontal transmission of Wolbachia between different psyllid hosts.%【目的】探明不同地理种群的柑橘木虱Diaphorina citri Kuwayama和柑橘粉虱Dialeurodes citri Ashmead体内昆虫内共生菌的种类及其感染率,并以Wolbachia共生菌为代表,对其系统发育关系进行分析,为今后自共生菌角度研发柑橘木虱和柑橘粉虱的新型

  12. HPLC测定不同基原陈皮药材中橙皮苷含量%Content Determination of Hesperidin from Different Kinds of Pericarpium Citri Reticulatae by HPLC

    Institute of Scientific and Technical Information of China (English)

    胡志军; 陈建秋

    2012-01-01

    目的:采用高效液相色谱法测定不同基原陈皮药材中橙皮苷含量,为科学评价及有效控制其质量提供可靠方法.方法:采用高效液相色谱法,Baseline C18色谱柱(4.60 mm x250 mm,5 μm),流动相甲醇-水(1%乙酸溶液)(50:50),检测波长283 nm,等度洗脱,流速1.0 mL·min -1,柱温室温,进样量20μL.结果:橙皮苷质量浓度在0.002 -0.040 g·L-1呈良好的线性关系(r =0.9999),平均回收率102.3% (n =9),RSD 1.6%.含量测定结果表明,同一产地不同基原陈皮药材中橙皮苷含量存在显著差异.结论:该方法简单、可行,适用于不同基原陈皮药材中橙皮苷的含量测定以及质量评价.%Objective: To determine the content of the hesperidin in six different kinds of pericarpium citri reticulatae and gained a method to estimate and control the quality of medical material and effectively. Method; The HPLC was adopted to do this examination, the separat on was performed on a Baseline C18 column (4.60 mm x250 mm, 5 μm), methanol-water (1% acetic acid solution) (50= 50) was used as the mobile phase with isocratic elution, the detective wavelength was at 283 nm, the flow rate was 1.0 mL · min-1, the column temperature was room temperature and the injecti on volume was 20 u,L. Result; The hesperidin showed a good linearity in the range of 0. 002 -0. 040 g · L-1 ( r = 0. 999 9 ) , the average recovery was 102. 3 % ( n = 9) , RSD 1.6%. The contents of hesperidin in peels of citrus was varied from different species. Conclusion: The method is simple and available, which can be used to determine and estimate hesperidin in different kinds of pericarpium citri reticulatae.

  13. 阿维菌素与印楝油对柑桔红蜘蛛的增效作用%Synergistic Effect of Abamectin and Neem Oil Against Panonychus citri Me Gregor

    Institute of Scientific and Technical Information of China (English)

    熊忠华; 李保同; 熊件妹; 张纪利

    2012-01-01

    Toxicity of abamectin and neem oil against Panonychus citri and the synergistic effect of their mixture were evaluated in the lab. It was showed that, for the contact toxicity of abamectin and neem oil to adult famales of Panonychus citri, the LCX value was 0.01 jig/mL and 6 579.87 u.g/mL, respectively, after 24 h treatment. The optimal mixture ratio of abamectin with neem oil was determined by co-toxicity factor and eo-toxicity coefficient method. The results indicated that, among the 6 combinations of theses two active ingredients, the co-toxicity factor of combination at the ratios of 1 : 100 and 1 : 125 for abamectin vs neem oil was 24.50 and 31.08, respectively. Furthermore, combination at the ratio of 1 : 125 showed the highest synergism with a co-toxicity coefficient of 160.76.%室内测定阿维菌素与印楝油对柑桔红蜘蛛的毒力及其复配组合的联合作用.毒力测定结果表明,阿维菌素与印楝油对柑桔红蜘蛛雌成螨处理后24 h的LC50分别为0.01 μg/mL和6579.87 μg/mL.以共毒因子法评价阿维菌素与印楝油6种复配组合的联合作用,结果显示,二者以1∶100和1∶125两种比例复配对柑桔红蜘蛛雌成螨的共毒因子分别为24.50和31.08,具增效作用;进一步以共毒系数法确定阿维菌素与印楝油以1∶125的比例复配增效作用最为显著,共毒系数为160.76.

  14. 防治果园周边柑橘木虱控制黄龙病效果研究%Study on control effectiveness of Huanglongbing based on eradication of Asian Citrus Psyllid Diaphorina citri Kuwayama surrounding citrus orchard

    Institute of Scientific and Technical Information of China (English)

    毛润乾; 吴东; 何勇; 陈世伟; 贤家旭; 郑基焕

    2013-01-01

    In new citrus orchards,virus-free citrus seedling were planted,the Asian citrus psyllid Diaphorina citri was regularly monitored and controlled during the new shoot sprouting period,especially in the early summer shoot period and early autumn shoot period.Meanwhile,the host plants of citrus psyllid surrounding the citrus orchard were surveyed,and the citrus psyllid on these host plants were eradicated by regularly sprayed chemical pesticides in late February,early May,late August and late November each year.The results show that,the psyllid and Huanglongbing in citrus orchard were effectively controlled.The Asian citrus psyllid populations in citrus orchard were very low,the largest number of adults was 2.25 per ha,and Huanglongbing was decreased gradually as well after the practice of this management,from 8‰ in 2008 to 0.1‰ in 2012.%在新种柑橘园中栽种柑橘无毒苗,定期监测和防治果园内柑橘木虱Diaphorina citri Kuwayama,防治时期为各新梢萌芽期,重点防治期为早夏梢期和早秋梢期;与此同时,调查柑橘园周围柑橘木虱寄主植物,每年2月下旬、5月上旬、8月下旬和11月下旬定期喷药,清除柑橘园周围寄主植物上的柑橘木虱.结果表明,果园内柑橘木虱和黄龙病均得到有效的控制,果园内柑橘木虱种群数量控制在很低的水平,最高为2.25头/公顷,最低为θ;黄龙病发病率也很低,2008年为8‰,实施该技术后,发病率逐年下降,2012年降低到0.1‰.

  15. 几种杀虫剂对柑橘木虱的毒力及防效研究%Toxicity and Control Effect of Several Pesticides to Diaphorina citri Kuwayama

    Institute of Scientific and Technical Information of China (English)

    张小艳; 李韬; 范国成; 胡菡青; 林雄杰; 阮传清; XIAYu-lu; 蔡子坚; 刘波

    2013-01-01

    在室内条件下,采用浸虫法测定了10种杀虫剂对柑橘木虱的毒力,结果表明,高效氯氟氰菊酯和溴氰菊酯对柑橘木虱成虫具有较高的毒力,其24 h的 LC50值分别为2.116、3.030 mg · L -1,而吡蚜酮、螺虫乙酯和吡虫啉毒力较差,尤其以吡蚜酮的毒力最差,其24 h的LC50值为2025.489 mg · L -1;采用灌根施药法测定了4种内吸性杀虫剂对柑橘木虱成虫的防效,4种供试验药剂各处理对柑橘木虱成虫的短期效果较差,但10%烯啶虫胺2000倍液、70%吡虫啉14000倍液及7000倍液处理灌根施药后14~28 d对柑橘木虱成虫的防效均保持在87%以上,至药后28 d防效高达97%以上,持效期长。%The toxicity of 10 pesticides and field control efficacy of 4 systemic pesticides to Diaphorina citri were tested with dipping and root pouring respectively for effectively controlling the citrus psylla .The result of indoor determination showed that ,after 24h treatment ,the toxicity of pesticides against Diaphorina citri in LC50 of lambda-cyhalothrin and decamethrin was 2.116 and 3.030 mg · L -1 ,respectively ,which were higher than it of Pymetrozine ,spirotetramat and Imidacloprid .The lowest toxicity was pymetrozine with LC50 2 025.489 mg · L -1 . Though the effect of 4 systemic pesticides controlling citrus psylla in the field was low in short term with root pouring treatment ,the control effects of 10% nitenpyram AS 2 000 times、70% imidacloprid WG 14 000 times and 7 000 times were maintained at 87% during the 14-28 d of the treatment and even reached higher than 97% 28 days after treatments .

  16. 橘全爪螨种群动态与环境因素的研究%Study on the Population Dynamics and Environmental Factors of Citrus Red Mite ( Panonychus citri )

    Institute of Scientific and Technical Information of China (English)

    甘宗义; 朱红艳; 谭荣荣; 刘先琴; 王盛桃

    2011-01-01

    通过田间试验和数理统计对橘全爪螨(Panonychus citri Me Gregor)田间动态及环境因素对其的影响进行探讨.橘全爪螨在湖北温州蜜柑产区一年有2次虫口高峰,分别出现在5~6月和9~10月.温度是影响橘全爪螨生长发育的主要因素,螨与卵的田间增长在旬平均气温15~20 ℃时最快.虫口高峰一般出现在22~27℃、相对湿度为75%~83%时.长期阴雨不利于其种群发展,旬雨量超过100 mm引起种群密度急剧下降.如果环境条件适合则种群增殖力随其成螨密度增加而增强.田间天敌混合种群与害螨田间动态符合Leslie模型,当天敌量达到每叶0.05~0.08头时,可控制害螨种群发展.%Population dynamics and environmental factors of citrus red mite (Panonychus citri) were studied by field test and mathematical statistics. The results showed that there were two population peaks of the mite in each year in "Satsuma Man darin" producing area of Hubei province, appearing at May to June and September to October respectively. Atmospheric temperature was the primary factor affecting the growth and development of the mite. The highest increasing speed of mites and eggs appeared at 15~20℃; and the population peak usually appeared when temperature was 22~27℃ ,and humidity was 75% ~83%. Long time of rainfall could inhibit the development of population as the population would decrease sharply if the pre cipitation of ten days exceeded 100 mm. The population proliferation ability would increase according to the increase of adult mite density. The dynamics of mite population and its enemies coincide with Leslie Patter. When the density of mites enemies (Stethorus punctillum,etc) was 0.05-0.08 head per leaf, the population development of the harmful mite could be controlled.

  17. 防治橘臀纹粉蚧药剂的室内筛选%Insecticide Screening for the control of Planococcus citri(Risso)(Homoptera: Pseudococcidae) in the laboratory

    Institute of Scientific and Technical Information of China (English)

    郭莹; 刘长明; 吴梅香; 杨广

    2012-01-01

    为有效地控制橘臀纹粉蚧Planococcus citri(Risso)发生,测定了6种农药在田间使用浓度下对该虫的致死效果.结果表明,在室内条件下,吡虫啉、烯啶虫胺、啶虫脒、阿维菌素和高效氯氰菊酯对1龄若虫的防治效果较好,用药后72 h校正死亡率均在80.0%以上,而杀扑磷仅74.8%.在防治应用中,建议推荐吡虫啉,烯啶虫胺,啶虫脒3种药剂,同时应针对不同虫态适当调整用药浓度和施药时间,以达到理想的防治效果.

  18. A specific interdomain interaction preserves the structural and binding properties of the ModA protein from the phytopathogen Xanthomonas citri domain interaction and transport in ModA.

    Science.gov (United States)

    Santacruz-Perez, Carolina; Pegos, Vanessa Rodrigues; Honorato, Rodrigo V; Verli, Hugo; Lindahl, Erik; Barbosa, João Alexandre Ribeiro Gonçalves; Balan, Andrea

    2013-11-01

    The periplasmic-binding proteins in ATP-binding cassette systems (ABC Transporters) are responsible for the capture and delivery of ligands to their specific transporters, triggering a series of ATP-driven conformational changes that leads to the transport of the ligand. Structurally consisting of two lobes, the proteins change conformation after interaction with the ligand. The structure of the molybdate-binding protein (ModA) from Xanthomonas citri, bound to molybdate, was previously solved by our group and an interdomain interaction, mediated by a salt bridge between K127 and D59, apparently supports the binding properties and keeps the domains closed. To determinate the importance of this interaction, we built two ModA mutants, K127S and D59A, and analysed their functional and structural properties. Based on a set of spectroscopic experiments, crystallisation trials, structure determination and molecular dynamics (MD) simulations, we showed that the salt bridge is essential to maintain the structure and binding properties. Additionally, the MD simulations revealed that this mutant adopted a more compact structure that packed down the ligand-binding pocket. From the closed bound to open structure, the positioning of the helices forming the dipole and the salt bridge are essential to induce an intermediate state.

  19. A specific interdomain interaction preserves the structural and binding properties of the ModA protein from the phytopathogen Xanthomonas citri domain interaction and transport in ModA.

    Science.gov (United States)

    Santacruz-Perez, Carolina; Pegos, Vanessa Rodrigues; Honorato, Rodrigo V; Verli, Hugo; Lindahl, Erik; Barbosa, João Alexandre Ribeiro Gonçalves; Balan, Andrea

    2013-11-01

    The periplasmic-binding proteins in ATP-binding cassette systems (ABC Transporters) are responsible for the capture and delivery of ligands to their specific transporters, triggering a series of ATP-driven conformational changes that leads to the transport of the ligand. Structurally consisting of two lobes, the proteins change conformation after interaction with the ligand. The structure of the molybdate-binding protein (ModA) from Xanthomonas citri, bound to molybdate, was previously solved by our group and an interdomain interaction, mediated by a salt bridge between K127 and D59, apparently supports the binding properties and keeps the domains closed. To determinate the importance of this interaction, we built two ModA mutants, K127S and D59A, and analysed their functional and structural properties. Based on a set of spectroscopic experiments, crystallisation trials, structure determination and molecular dynamics (MD) simulations, we showed that the salt bridge is essential to maintain the structure and binding properties. Additionally, the MD simulations revealed that this mutant adopted a more compact structure that packed down the ligand-binding pocket. From the closed bound to open structure, the positioning of the helices forming the dipole and the salt bridge are essential to induce an intermediate state. PMID:24035743

  20. Synergistic Effect of Three Substances on Paris polyphylla Smith against Panoychus citri McGregor%3种物质对七叶一枝花防治柑桔全爪螨的增效作用

    Institute of Scientific and Technical Information of China (English)

    周顺玉; 蒋春先; 杨群芳; 李庆

    2007-01-01

    研究了邻苯二酚、氮酮和硫酸钙3种化学物质对七叶一枝花(Paris polyphylla Smith)提取物防治柑桔全爪螨(Panoychus citri McGregor)的增效作用.结果表明:七叶一枝花乙醇、氯仿、乙酸乙酯提取物单用对柑桔全爪螨的致死中浓度(LC50)分别为1 588.537、1480.071、1 402.954 μg/ml;邻苯二酚对七叶一枝花乙醇、氯仿、乙酸乙酯提取物均有显著增效作用,LC50分别为284.506、582.295、897.323 μg/ml,分别增效5.6、2.5和1.6倍;氮酮仅对七叶一枝花乙醇提取物有增效作用,增效2.1倍;硫酸钙对七叶一枝花氯仿、乙酸乙酯提取物均有增效作用,分别增效1.4和2.1倍.

  1. Microwave-based Method for Genomic DNA Extraction and Rapid Detection Method from Xanthomonas axonopodis pv.citri%柑桔溃疡病菌基因组DNA的微波法抽提及快速检测

    Institute of Scientific and Technical Information of China (English)

    姚廷山; 周常勇; 胡军华; 冉春; 李鸿筠; 刘浩强; 肖田

    2012-01-01

    利用微波热震惊提取固体表面柑桔溃疡病基因组DNA并加以优化,所得到的基因组DNA可作为PCR反应的模板进行16SrDNA基因有效扩增.与柑桔溃疡病基园组DNA其他抽提方法相比较,微波法更适用于该病的快速检测,具有快速、筒便、费用低廉等特点,且对设备的要求不高,用特异性引物XCF/XCR可实现柑桔溃疡病菌的快速鉴定.%The optimized microwave extraction was conducted to attract the genome of citrus canker disease. The genome extraction method was fast,easy to handle with low cost The extracted DNA was suitable for PCR. The microwave-based method was suitable for fast identification compare to other methods. The method was effective, easy and fast, so it was recommended that the extraction method was applied for the detection of Xanthomonas oxonopodit pv. citri using primers XCF/XCR.

  2. Repellency effects of secondary compounds of Ajuga nipponensis Makino against citrus red mite Panonychus citri (McGregor)%紫背金盘(Ajuga nipponensis)次生物质对桔全爪螨(Panonychus citri)的驱避作用

    Institute of Scientific and Technical Information of China (English)

    徐迪; 钟耀垣; 曾玲; 陈永; 岑伊静; Beattie GAC

    2008-01-01

    研究了紫背金盘Ajuga nipponensis Makino各溶剂提取物和部分化合物对桔全爪螨Panonychus citri McGregor雌成螨及其产卵的驱避作用.结果表明,石油醚萃取物、乙酸乙酯萃取物具有较强的生物活性.在0.1 g · L-1时, 石油醚和乙酸乙酯萃取物对该螨处理1d后的产卵忌避率分别为:84.86%、69.88%;2d后为89.49%、82.19%;对雌成螨驱避率分别为:85.08%、68.66%;2d后为50.96%、69.84%.乙酸乙酯萃取物经分离得到四类化合物,结果表明:馏分Ⅰ为长链脂肪酸混合物,具有较强生物活性,2000μg/ml和1000μg/ml处理1d后,产卵忌避率分别为:80.77%、74.77%;2d后为73.81%、72.59%.2000μg/ml处理1d后对雌成螨的驱避率为:69.88%;2d后为74.24%.刺槐素Ⅱ、新克罗烷化合物Ⅲ和β-蜕皮甾酮Ⅳ在2000μg/ml均不表现活性.对馏分Ⅰ中的4个主要化合物单体进行活性测定,结果表明:十六烷酸、十六烷酸甲酯、十六烷酸乙酯和十八烷酸甲酯在2000μg/ml处理时,1d后,产卵驱避率分别为:75.18%、61.76%、59.18%和66.49%;2d后产卵驱避率为:66.67%、31.15%、46.75%和44.84%;雌成螨驱避率分别为:1d后,67.53%、63.79%、59.26%和68.00;2d后,67.23%、43.96%、48.23%和64.19%.在1000μg/ml处理时,1d 后,产卵驱避率分别为:59.21%、59.16%、57.02%和61.40%;1d后,雌成螨驱避率分别为:69.64%、61.43%、55.76%和64.00%.

  3. 柑橘木虱黄龙病菌携带量与其内生菌群相关性%Correlation of Candidatus Liberibacter asiaticus and the Endophytic Community in Diaphorina citri

    Institute of Scientific and Technical Information of China (English)

    孙丽琴; 殷幼平; 王芳; 吴晓芳; 王中康

    2014-01-01

    频率均达到100%,表明其为木虱体内常驻细菌;对木虱不同部位(头、胸、腹)内生细菌16S rDNA的PCR-DGGE图谱显示,带菌与不带菌木虱中细菌种群差别明显,带菌状况相同的木虱不同部位之间差别不明显。其中优势条带10(Wolbachiasp.)、12(Wolbachiapipientis)、13(Syncytiumendosymbiont of Diaphorina citri)、14(Uncultured bacterium)、19(Serratia marcescens)、21和22(均为嗜麦芽寡养单胞菌Stenotrophomonasmaltophilia)在木虱体内稳定存在,带菌木虱腹部特有优势内生细菌为Enterobacter sp.,木虱中同样也存在次级内生菌Wolbachia。q-PCR的结果验证了所选的3种细菌在前期传统分离培养和16S rDNA-PCR-DGGE中结果的可靠性,同时表明肠杆菌属在8份样品中与黄龙病菌呈正相关关系。【结论】黄龙病菌进入木虱体内会改变木虱内生细菌菌群种类和结构;嗜气芽孢杆菌(B. aerophilus)在柑橘木虱体内稳定存在,为木虱体内常驻菌群;Enterobacter sp.与黄龙病菌带菌量呈正相关,推测其可能与黄龙病菌互作。%[Objective]The objective of this study is to analyze the endophytic bacteria in Diaphorina citri which may affect the pathogenesis of Candidatus Liberibacter asiaticus, and to provide a basis for artificial culture of Ca. L. asiaticus, prevent and control of HLB. [Method] The diversity of cultivable endophytic bacteria in different samples of D. citri with or without Ca. L. Asiaticus from different geographical origins were compared by traditional isolation and culture methods. D. citri with and without Ca. L. asiaticus were divided into three parts:the head, thorax and abdomen, respectively. Then V6-V8 area of 16S rDNA were amplified after extracting DNA, the endophytic bacteria in D. citri of with or without HLB pathogen and in different parts of the same carrier state were compared by 16S rDNA-PCR-DGGE. The relative amount in 8 D. citri samples of Bacillus

  4. 5种寄主上的尼氏真绥螨对柑橘红蜘蛛的捕食能力差异研究%Difference of Predatory Capacity for Euseius nicholsi from Five Different Host Plants Preying on Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    熊忠华; 熊件妹; 李海霞; 王新辉

    2012-01-01

      室内测定了5种寄主上的尼氏真绥螨对柑橘红蜘蛛的日捕食量和持续捕食能力。结果表明,柑橘上的尼氏真绥螨成螨对柑橘红蜘蛛成螨的日均捕食量最大,显著高于紫苏;而梧桐、薄荷和茶叶3种寄主上的尼氏真绥螨对柑橘红蜘蛛雌成螨的捕食力与柑橘上的无显著差异。对柑橘红蜘蛛若螨的捕食能力以薄荷和梧桐上的显著为高,柑橘和茶叶上的次之,紫苏上的最低;而5种寄主上的尼氏真绥螨对柑橘红蜘蛛幼螨的日均捕食量之间无显著差异。对柑橘红蜘蛛成螨的持续捕食能力结果显示,各处理连续3天的日均捕食量基本呈现略微降低的趋势,但3天之间均无显著差异。上述结果证明不同寄主上的尼氏真绥对柑橘红蜘蛛的捕食能力存在差异,且对柑橘红蜘蛛成螨的捕食能力较为稳定。%  The daily and persistent predatory capacity of Euseius nicholsi from five different host plants on Panonychus citri were determined in the lab. The results showed that the daily predatory amount of a female adult from citrus on adults of P. citri was significantly higher then perilla fruitescens. And the three others had no significant difference from the adults of E. nicholsi. The predatory number of E. nicholsi from Mentha haplocalyx.brip. and Fimiana simplex on mites nymphs were significantly higher than others, the second were the E. nicholsi from citrus and tea plant. However, there were no significant difference of the predatory amount on larvae of P. citri among the five treatments of the persistent predatory capacity on adults of P. citri, which indicated that there were no significant difference,although the tendency of the daily average predatory amount was slightly decreasing in the three days. It could be proved that there were different of the predatory capacity of E. nicholsi from different host plants on P. citri and the persistent predatory capacity on

  5. 源于重庆产大红袍红橘的陈皮挥发油成分研究%Study on Volatile Oil of Citri Reticulatae Pericarpium in Citrus reticulata 'Dahongpao' from Chongqing

    Institute of Scientific and Technical Information of China (English)

    王坚; 王刚

    2012-01-01

    OBJECTIVE: To investigate the volatile oil of Citri Reticulatae Pericarpium in Citrus reticulata 'Dahongpao' from Chongqing. METHODS: The volatile oil was extracted by steam distillation and analyzed by GC-MS. The overlapped peaks of TIC were resolved by the programs of GC-MS data analysis and AMDIS. RESULTS: A total of 70 compounds in volatile oil were identified, accounting for 96.343% of total content. The five compounds that had the highest content were limonene, linalool, thymol, γ-terpinene and α-sinensal, accounting for 48.089% , 16.066% , 6.776% , 5.916% , and 2.899% , respectively. Monoterpenes (13 compounds) had the largest content, representing 56.062%. The oxygenated compounds (44 compounds) occupied a large proportion (36.497% ), and the main compounds were alcohol, phenol, and aldehyde. CONCLUSION: The volatile oil of Citri Reticulatae Pericarpium in C. Reticulata 'Dahongpao'from Chongqing belongs to the chemotype of Limonene/Linalool. The combined use of GC-MS data analysis and AMDIS can efficiently solve the difficulty in the qualitative and quantitative analysis of overlapped peaks of TIC. The study will boost the development and utilization of C. Reticulata ' Dahongpao' produced in Chongqing deeply.%目的:研究源于重庆产大红袍红橘的陈皮挥发油成分.方法:采用水蒸气蒸馏法提取挥发油,气相色谱-质谱(GC-MS)联用技术测定挥发油成分;利用GC-MS数据分析与自动质谱退卷积定性系统(AMDIS)软件对挥发油总离子流(TIC)中的重叠峰进行解析.结果:共定性、定量了70个化合物,总含量为96.343%.含量最高的5个化合物分别为柠檬烯、芳樟醇、百里香酚、y-萜品烯、α-甜橙醛,分别占总含量的48.089%、16.066%、6.776%、5.916%、2.899%.单萜烯(共13个)是含量最大的一类化合物,占56.062%;含氧化合物(共44个)占的比重较大,为36.497%,主要的几类物质是醇、酚、醛.结论:源于重庆产大红袍红橘的陈

  6. Isolation and identification of compound with acaricidal activity from Fructus arctii against Panonychus citri%牛蒡子杀柑橘全爪螨活性成分的分离与鉴定

    Institute of Scientific and Technical Information of China (English)

    胡军华; 马丽娜; 姚廷山; 冉春; 刘浩强; 李鸿筠; 雷慧德

    2012-01-01

    【目的】为了探明牛蒡子杀柑橘全爪螨的活性成分,【方法】采用杀螨活性追踪、溶剂萃取、硅胶柱层析、紫外吸收、颜色反应、气相色谱一质谱联用(GC—MS)等方法研究牛蒡子乙醇提取物对柑橘全爪螨的抑制作用,并分离和鉴定其杀螨活性成分。【结果】结果表明,牛蒡子组分L1-2杀柑橘全爪螨的活性最高,触杀毒力高达0.0025g·L^(-1);组分L1—2中含有共轭双键或三键化合物,主要包括十六碳烷酸甲酯、十八烷酸甲酯、三十烷酸甲酯、三十一烷酸甲酯、十八碳二烯酸甲酯等9种主要成分,总含量达到85.32%,还有少量醛类、烯醇、烯烃类物质。【结论】牛蒡子杀柑橘全爪螨的活性成分主要为脂肪酸类物质。%[Objective]The objective of the study is to elucidate the compound with acaricidal activity from Fructus Arctii against Panonychus citri. [Method]The active ingredient of the ethanol extract of Fructus A rctii was separated by different polarity solvent extraction, column chromatography, thin layer chromatography, determination of the contact toxicity of different components. [Result]By the leaf impregnation bioassay, L1-2 was the strongest activity, and the contact toxicity was up to 0.002 5 g·L^(-1) against Panonychus citri. UV absorption by the reaction and color identification proved that L1-2 contains conjugated double bonds or three bonds. The chemical composition of L1-2 potation was analyzed by the GC- MS - liquid mass spectrometry. It was determined that 9 compounds, in which represented 85.32% of total content, were present in the unsaturated fatty substances. The essential oils contained mainly octadecanoic acid methyl ester, hexadecanoic methyl este, pentadecanoic methyl ester, triacontanoic methyl ester, 9- octadecanoic methyl ester, 8-octadecanoic methyl ester, 11-octadecanoic methyl ester, 8,11-octadecanoic methyl ester, 7,10-octadecanoic methyl

  7. Differences in stylet sheath occurrence and the fibrous ring (sclerenchyma) between xCitroncirus plants relatively resistant or susceptible to adults of the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Ammar, El-Desouky; Richardson, Matthew L; Abdo, Zaid; Hall, David G; Shatters, Robert G

    2014-01-01

    The Asian citrus psyllid (ACP, Diaphorina citri, Hemiptera: Liviidae), is the principal vector of the phloem-limited bacteria strongly associated with huanglongbing (HLB), the world's most serious disease of citrus. Host plant resistance may provide an environmentally safe and sustainable method of controlling ACP and/or HLB. Two xCitroncirus accessions (hybrids of Poncirus trifoliata and Citrus spp.), that are relatively resistant (UN-3881) or relatively susceptible (Troyer-1459) to ACP adults with regard to adult longevity, were compared in relation to ACP feeding behavior and some structural features of the leaf midrib. The settling (putative feeding/probing) sites of ACP adults on various parts of the leaf were not influenced primarily by plant accession. However, fewer ACP stylet sheaths were found in the midrib and fewer stylet sheath termini reached the vascular bundle (phloem and/or xylem) in UN-3881 compared to Troyer-1459 plants. Furthermore, in midribs of UN-3881 leaves the fibrous ring (sclerenchyma) around the phloem was significantly wider (thicker) compared to that in midribs of Troyer-1459 leaves. Our data indicate that feeding and/or probing by ACP adults into the vascular bundle is less frequent in the more resistant (UN-3881) than in the more susceptible (Troyer-1459) accessions. Our results also suggest that the thickness of the fibrous ring may be a barrier to stylet penetration into the vascular bundle, which is important for successful ACP feeding on the phloem and for transmitting HLB-associated bacteria. These results may help in the development of citrus plants resistant to ACP, which in turn could halt or slow the spread of the HLB-associated bacteria by this vector. PMID:25343712

  8. Characterization of the Relative Abundance of the Citrus Pathogen Ca. Liberibacter Asiaticus in the Microbiome of Its Insect Vector, Diaphorina citri, using High Throughput 16S rRNA Sequencing.

    Science.gov (United States)

    Fagen, Jennie R; Giongo, Adriana; Brown, Christopher T; Davis-Richardson, Austin G; Gano, Kelsey A; Triplett, Eric W

    2012-01-01

    The relationship between the causal agent of Huanglongbing (HLB), Ca. Liberibacter asiaticus(Las), and the naturally occurring endosymbiotic community of its insect vector, the Asian citrus psyllid (ACP), Diaphorina citri, was studied. Variation was observed in the titer of Las within an ACP population feeding on the same material. The cause of this disparity is unknown, and has implications for Las transmission and the spread of HLB. This study utilizes culture independent methods to establish the relationship between the ACP's microbial community and Las acquisition. DNA from 21 psyllids was amplified using universal 16S rRNA primers with Illumina adaptor regions and a sample-specific 7- base identifier. These amplicons were then batch-sequenced on the Illumina platform. The resulting sequences were separated by the identifier, and compared to known sequences in a 16S rRNA database. The microbial communities of each psyllid were compared to determine whether a correlation exists between the ACP's endosymbionts and level of Las acquisition.ACPs were dominated by the same four bacterialgenera regardless of the abundance of Ca.Liberibacter. A combination of qPCR and Illumina sequencing was used to establish an infection gradient among the sampled ACPs. The Ca. Liberibacter titer within the insect was found to have a strong negative relationship with an endosymbiont residing in the syncytium of the mycetocyte and a positive relationship with Wolbachia. These correlations have implications in the acquisition of Las by the ACP as well as the activities of Las within this vector.

  9. Differences in stylet sheath occurrence and the fibrous ring (sclerenchyma) between xCitroncirus plants relatively resistant or susceptible to adults of the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Ammar, El-Desouky; Richardson, Matthew L; Abdo, Zaid; Hall, David G; Shatters, Robert G

    2014-01-01

    The Asian citrus psyllid (ACP, Diaphorina citri, Hemiptera: Liviidae), is the principal vector of the phloem-limited bacteria strongly associated with huanglongbing (HLB), the world's most serious disease of citrus. Host plant resistance may provide an environmentally safe and sustainable method of controlling ACP and/or HLB. Two xCitroncirus accessions (hybrids of Poncirus trifoliata and Citrus spp.), that are relatively resistant (UN-3881) or relatively susceptible (Troyer-1459) to ACP adults with regard to adult longevity, were compared in relation to ACP feeding behavior and some structural features of the leaf midrib. The settling (putative feeding/probing) sites of ACP adults on various parts of the leaf were not influenced primarily by plant accession. However, fewer ACP stylet sheaths were found in the midrib and fewer stylet sheath termini reached the vascular bundle (phloem and/or xylem) in UN-3881 compared to Troyer-1459 plants. Furthermore, in midribs of UN-3881 leaves the fibrous ring (sclerenchyma) around the phloem was significantly wider (thicker) compared to that in midribs of Troyer-1459 leaves. Our data indicate that feeding and/or probing by ACP adults into the vascular bundle is less frequent in the more resistant (UN-3881) than in the more susceptible (Troyer-1459) accessions. Our results also suggest that the thickness of the fibrous ring may be a barrier to stylet penetration into the vascular bundle, which is important for successful ACP feeding on the phloem and for transmitting HLB-associated bacteria. These results may help in the development of citrus plants resistant to ACP, which in turn could halt or slow the spread of the HLB-associated bacteria by this vector.

  10. Differences in stylet sheath occurrence and the fibrous ring (sclerenchyma between xCitroncirus plants relatively resistant or susceptible to adults of the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae.

    Directory of Open Access Journals (Sweden)

    El-Desouky Ammar

    Full Text Available The Asian citrus psyllid (ACP, Diaphorina citri, Hemiptera: Liviidae, is the principal vector of the phloem-limited bacteria strongly associated with huanglongbing (HLB, the world's most serious disease of citrus. Host plant resistance may provide an environmentally safe and sustainable method of controlling ACP and/or HLB. Two xCitroncirus accessions (hybrids of Poncirus trifoliata and Citrus spp., that are relatively resistant (UN-3881 or relatively susceptible (Troyer-1459 to ACP adults with regard to adult longevity, were compared in relation to ACP feeding behavior and some structural features of the leaf midrib. The settling (putative feeding/probing sites of ACP adults on various parts of the leaf were not influenced primarily by plant accession. However, fewer ACP stylet sheaths were found in the midrib and fewer stylet sheath termini reached the vascular bundle (phloem and/or xylem in UN-3881 compared to Troyer-1459 plants. Furthermore, in midribs of UN-3881 leaves the fibrous ring (sclerenchyma around the phloem was significantly wider (thicker compared to that in midribs of Troyer-1459 leaves. Our data indicate that feeding and/or probing by ACP adults into the vascular bundle is less frequent in the more resistant (UN-3881 than in the more susceptible (Troyer-1459 accessions. Our results also suggest that the thickness of the fibrous ring may be a barrier to stylet penetration into the vascular bundle, which is important for successful ACP feeding on the phloem and for transmitting HLB-associated bacteria. These results may help in the development of citrus plants resistant to ACP, which in turn could halt or slow the spread of the HLB-associated bacteria by this vector.

  11. 亚洲柑桔木虱若虫在寄主上的转移和扩散研究%The movement and spread of nymphs of Diaphorina citri Kuwayama on host plants

    Institute of Scientific and Technical Information of China (English)

    吴丰年; 梁广文; CHEN Jian-Chi; 黄建邦; 岑伊静

    2013-01-01

    黄龙病是世界柑桔产业的一种毁灭性病害,亚洲柑桔木虱Diaphorina citri Kuwayama为黄龙病亚洲种和美洲种的媒介昆虫,其成虫和高龄若虫都能传病.本文研究亚洲柑桔木虱若虫在感染黄龙病及健康寄主上的转移和扩散规律,发现3龄及3龄以上若虫在柑桔植株垂直和水平位置的嫩梢之间转移现象十分明显,但在黄龙病植株上转移速度较健康植株慢,且嫩梢间的转移速度受虫口密度的影响,密度越高转移速度越快.在有选择的条件下,水平位置转移过程中若虫更趋向黄龙病植株.此外,在健康寄主上的木虱若虫有明显向植株下部转移的现象,向下部转移的若虫个体数显著高于黄龙病寄主.本文明确了木虱若虫的扩散规律和寄主感染黄龙病对其转移和扩散产生的影响,为柑桔木虱和黄龙病防治提供参考.

  12. 辐照结合不同温度处理对柑橘红蜘蛛成螨的影响%Combined effects of temperature treatment and irradiation on citrus red mites (Panonychus citri Mcgregor)

    Institute of Scientific and Technical Information of China (English)

    邓乐晔; 张珂; 付昊昊; 祝绍文; 李志斌; 胡美英; 赵海明; 翁群芳

    2014-01-01

    [目的]研究辐照结合不同温度处理对柑橘红蜘蛛(Panonychus citri Mcgregor)成螨的影响,以寻求提高辐照处理柑橘红蜘蛛成螨效果的方法.[方法]以0,100,200,300和400 Gy的剂量辐照处理柑橘红蜘蛛成螨后,分别置于5,10,15,20和25℃条件下饲养,观察成螨死亡率及其后代繁殖情况.[结果]同一剂量下,柑橘红蜘蛛成螨死亡率随温度升高而增大,辐照后置于低温条件下可抑制成螨的死亡;用400 Gy剂量辐照处理柑橘红蜘蛛成螨后置于25℃条件下15d,可使成螨死亡率达到100.00%.低温对柑橘红蜘蛛成螨产卵量及卵的孵化率有显著抑制作用,成螨经100和200 Gy辐照处理后置于5℃条件下,产卵量为0;成螨经300 Gy处理后置于温度低于20℃(包括20℃)条件下,可100%抑制卵的孵化.[结论]当温度为5℃时,100 Gy辐照处理柑橘红蜘蛛成螨即可达到100%不育.

  13. Study on distribution and fecundity of Panonychus citri Me Gregor on different host plants%柑桔全爪螨在不同寄主植物上的分布及繁殖力研究

    Institute of Scientific and Technical Information of China (English)

    徐淑; 李鹏燕; 陈凯歌; 陈炳旭

    2014-01-01

    在田间调查砂糖桔、甜橙、沙田柚和香柠檬4种寄主植物不同部位柑桔全爪螨(Panonychus citri Me Gregor)的种群数量,并通过室内饲养比较柑桔全爪螨在以上4种寄主植物上的繁殖力.结果表明:砂糖桔、甜橙、沙田柚以及香柠檬4种植株上部叶片柑桔全爪螨的种群数量多于中、下部叶片;砂糖桔、香柠檬上柑桔全爪螨的平均数量相当(分别为12.02、12.07头/叶),均显著多于甜橙和沙田柚,沙田柚上数量最少,仅为4.69头/叶.1~3代柑桔全爪螨在砂糖桔、甜橙、沙田柚以及香柠檬上的平均产卵量均相当,单雌日产卵量为3~7粒;4种寄主植物上柑桔全爪螨的卵历期及卵的孵化率均存在一定差异,卵的历期为5~8 d,孵化率为90%~98%.

  14. Studies on the relationship between feeding sites and bacterium acquisition efficiency of Diaphorina citri on Huanglongbing-infected citrus%柑橘木虱取食黄龙病柑橘部位与获菌效率的关系

    Institute of Scientific and Technical Information of China (English)

    黄金萍; 黄建邦; 高娃; 曾丽霞; 黄有明; 宋银平; 岑伊静

    2015-01-01

    [Objective]To clarify the best feeding sites and the shortest time of Diaphorina citri Kuwayama in spreading Huanglongbing ( HLB ) and to provide guidance for the prevention and control of HLB .[Method]The bacterium acquisition efficiency of D.citri was tested by PCR , which had been fed on three different parts:tender shoots , mature leaves and old leaves of infected Citrus reticulata Blanco .cv. Mashuiju and Citrus sunki Hort.ex Tanaka for 24 h.[Result and conclusion]The results showed that the infected rates of D.citri were significantly different among the three parts of C.reticulata.The infected rate on mature leaves was the highest and old leaves was the lowest .The bacterium acquisition efficien-cies were also different among the three parts of C.sunki.The infected rates of old and mature leaves were both significantly higher than those of tender shoots .There was no significant difference between the old and mature leaves .The bacterium acquisition efficiency of D.citri feeding on tender shoots of C.re-ticulata was significantly higher than that on C.sunki, while on old leaves of C.sunki were significantly higher than that on C.reticulate, and there was no significant difference between the 2 species when feeding on mature leaves .The two hosts had the same infected rate of 36 .67%when compared feeding on the whole plants .%目的明确柑橘木虱Diaphorina citri 获毒的最佳取食部位和最短吸食时间,为生产实践中防治柑橘黄龙病提供依据.方法通过PCR测定了健康的柑橘木虱取食感染黄龙病的马水橘Citrus reticulata Blanco.cv.Mashuiju和酸橘Citrus sunki Hort.ex Tanaka的嫩梢、成熟叶和老叶24 h后的获菌效率.结果和结论取食马水橘3个部位的获菌效率差异显著:成熟叶>嫩梢>老叶.取食酸橘3个部位的获菌效率也有差异:老叶>成熟叶>嫩梢,其中老叶和成熟叶的获菌效率均显著高于嫩叶,但前两者差异不

  15. 桔全爪螨对阿维菌素和甲氰菊酯的抗性现实遗传力及风险评估%Resistance Realized heritability and risk assessment of Panonychus citri to avermectin and fenpropathrin.

    Institute of Scientific and Technical Information of China (English)

    何恒果; 赵志模; 闫香慧; 王进军

    2011-01-01

    On the basis of resistance breeding and selection in laboratory, and by using the threshold trait analysis in quantitative genetics, this paper studied the realized resistance heritability of Panonychus citri (McGregor) collected from Beibei of Chongqing to avermectin and fenpropathrin, and predicted the resistance risk of P. Citri to these two acaricides. After 11- and 16-generations of selection with avermectin and fenpropathrin, the resistance of P. Citri to the two acaricides increased by 3. 8- and 29. 9-fold, and the realized resistance heritability was 0.0475 and 0. 1544, respectively. Under laboratory condition, to develop a 10-fold increase of resistance required 12-26 generations of selection for avermectin, and 7-16 generations of selection for fenpropathrin under the selection pressure of 50% -90% mortality for each generation. Under field condition, it would require more generations to develop the same resistance level. Comparing with bioacaricide avermectin , pyrethroid fenpropathrin had obviously higher resistance risk to P. Citri. The results provided references for the resistance management of P. Citri to acaricides.%在实验室抗性选育的基础上,应用数量遗传学中的域性状分析法,研究了桔全爪螨北碚种群对阿维菌素和甲氰菊酯2种杀螨剂的抗性现实遗传力,并对2种药剂在不同杀死率下抗性发展的速率进行了预测.结果表明:用阿维菌素和甲氰菊酯分别不连续汰选11及16代后,桔全爪螨对两者的抗性分别为3.8和29.9倍,抗性现实遗传力分别为0.0475和0.1544.在室内选择条件下,杀死率为50% ~90%时,要获得10倍抗性,甲氰菊酯仅需要7~16代,阿维菌素则需要12 ~26代.而在田间选择情况下,2种药剂都将需要更长的时间.抗性筛选结果表明,生物源农药阿维菌素的抗性风险明显低于菊酯类农药甲氰菊酯.试验结果可为桔全爪螨抗性治理提供参考.

  16. Screening Experiments for the Effective Fungicides of Black Rot Disease of Gonggan(Alternaria citri)%贡柑黑腐病有效防治药剂筛选

    Institute of Scientific and Technical Information of China (English)

    邓明学; 谢艳芳; 谭有龙; 覃旭; 覃星瑜; 覃宗典

    2012-01-01

    [目的]筛选防治贡柑黑腐病的有效药剂.[方法]用生长速率法和孢子萌发法测定苯醚甲环唑等15种药剂的EC50、EC95值,并做氟硅唑等5种药剂的田间药效试验.[结果]以EC95(mg a.i./L)排序,抑菌活性较高的有氟硅唑、吡唑醚菌酯·咪鲜胺、吡唑醚菌酯、苯醚甲环唑、咪鲜胺、代森锰锌、丙森锌、百菌清·多菌灵·代森锰锌;田间防效较好的有10%氟硅唑WP、25%苯醚甲环唑·咪鲜胺WP、50%百菌清·多菌灵·代森锰锌WP和72%代森锰锌·霜脲氰WP,而10%氟硅唑EW防效较差.[结论]耐雨水冲刷的杀菌剂和剂型防效较好.%[Aims] This paper aims to screen out the effective fungicides for controlling black rot disease of Gonggan(Alteranria citri). [Methods] The EC50 and EC95(mg a.i./L) of 15 different kinds of fungicides, such as ifenoconazole, pyraclostrobin, were tested with the both methods of the growth rate and spore emergence, meanwhile, the field control of five kinds of fungicides, such as flusilazole, were conducted. [Results] Sorting by EC,,, the effect on inhibition of mycelial growth and spore germination from high to low: flusilazole, pyraclostrobin+prochloraz, pyraclostrobin, difenoconazole, prochloraz, mancozeb, propineb. The field trial results showed that the following .fungicides have good effect: flusilazole 10% WP 1 g/L, difenoconazole+prochloraz 25% WP 1 g/L, chlorothalonil+carbendazim+mancozeb 50% WP 1.67 g/L and mancozeb+cymoxanil 72% WP 1.25 g/L, while flusilazole 10% EW 1 g/L with poor control efficiency. [Conclusions] The control effect is better of the fungicides whose formulations can resist rain erosion.

  17. 薇苷菊乙醇提取物对桔全爪螨种群的控制作用%Control effects of Mikania micrantha alcohol extract on citrus red mite Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    岑伊静; 庞雄飞; 徐长宝; 邓桥胜

    2005-01-01

    研究薇苷菊(Mikania micrantha)乙醇提取物对桔全爪螨(Panonychus citri)种群的控制作用,并比较其与常用杀螨剂哒螨灵的效果.在实验室用0.1、0.2、0.4 g·L-13个浓度提取物分别喷布桔全爪螨卵、幼螨和若螨,除了0.1 g·L-1浓度处理对卵没有效果外,该处理幼螨、若螨存活率以及另2个浓度处理3个螨态的存活率都显著下降.在非选择性试验条件下,用这3个浓度的提取物处理叶片饲养的桔全爪螨雌螨繁殖量显著减少,寿命也显著缩短.在田间用这3个浓度的提取物在20 d内连喷2次,桔全爪螨卵、幼螨和若螨的存活率都低于对照,干扰作用控制指数分别为0.518、0.292、0.277,即对种群增长控制的效果分别为48.2%、70.8%、72.3%,比15%哒螨灵乳油2000倍处理更有效控制桔全爪螨的田间种群.田间试验结果还表明,提取物处理的叶片比对照和哒螨灵处理的浓绿,而且对桔全爪螨的天敌较安全.

  18. Potential of predacious mite Neoseiulus californicus in controlling citrus red mite Panonychus citri%加州新小绥螨对柑橘全爪螨的控制潜力

    Institute of Scientific and Technical Information of China (English)

    覃贵勇; 李庆; 杨群芳; 王海建; 蒋春先

    2013-01-01

    为了确定加州新小绥螨Neoseiulus californicus (McGregor)的国内品系在生物防治中的潜力,采用捕食者功能反应方法,研究了加州新小绥螨、江原钝绥螨Amblyseius eharai Amitai et Swirski、尼氏真绥螨Euseius nicholsi (Ehara et Lee)和拟长毛钝绥螨A.pseudolongispinosus Xin,Liang et Ke对柑橘全爪螨Panonychus citri AaGregor的捕食作用,加州新小绥螨对柑橘全爪螨的功能反应可以很好地拟合HollingⅡ圆盘方程,对柑橘全爪螨卵的捕食能力显著高于其它3种捕食螨,4种捕食螨对柑橘全爪螨卵的功能反应参数a/Th分别为20.8342、6.9458、0和6.1634;加州新小绥螨对柑橘全爪螨卵、幼螨、前若螨、后若螨和成螨功能反应分别为20.8342、42.0721、29.1849、22.1204和5.6284.加州新小绥螨密度越大,柑橘全爪螨种群数量下降越快,在益、害比为5∶30下,柑橘全爪螨种群数量在第4天就能得到控制.结果表明,加州新小绥螨国内品系对柑橘全爪螨表现出很大的控制潜力.

  19. 7种杀螨剂常规使用浓度对柑橘全爪螨的防效%Study on Control Efficiency of the Recommended Concentration of Seven Acaricides on Panonychus citri (McGregor)

    Institute of Scientific and Technical Information of China (English)

    江晴

    2012-01-01

    The control efficiency of the recommended concentration of seven acaricides on Panonychus citri were detected in citrus orchard. The result of field efficacy trials showed that Azocyclotin 25% WP and Avermectins 1.8% EC showed the better quick-acting and lasting ef- fect. And Diafenthiuron 25%EC, Fenbutatin-Oxide 50% WP and 240g/L SC showed the better the lasting effect, but the quick-acting effect of them were poor, especially Fenbutatin-Oxide 50% WP. In addition, the quick-acting effect of Pyridaben 15% EC was better, only was worse than Azocyclotin 25% WP, but the lasting effect was worst in all tested acaricides. The quick-acting and lasting effect of Propargite 57% EC was ordinary in all tested acaricides, except the lasting effect of it was only significantly better than Pyridaben 15% EC.%本文比较了7种杀螨剂常规用量对柑橘红蜘蛛的田间药效,结果表明:速效性和持效性均较好的药剂为三唑锡25%可湿性粉剂和阿维菌素1.8%乳油;而丁醚脲25%乳油、苯丁锡50%可湿性粉剂和螺螨酯240克/升悬浮剂的速效性较差,但持效性较强,尤其是苯丁锡50%可湿性粉剂。此外,哒螨灵15%乳油的速效性在几种药剂中仅稍差于三唑锡25%可湿性粉剂,但持效性却是几种药剂中最差的;而炔螨特57%乳油相对其它药剂而言,速效性和持效性均表现一般,持效性也仅显著好于哒螨灵15%乳油。

  20. “绿满园”对红蜘蛛的生物活性及对三种蜘蛛的毒性测定%The controlling role of"Lümanyuan"to Panonychus citri and measurement of toxicity to three kinds of spiders

    Institute of Scientific and Technical Information of China (English)

    张梦蕾; 李亚东; 谢良善; 王金亮; 贺妮莎; 彭宇

    2011-01-01

    The slides viscose immersion method was taken to determine the toxicity of "Lümanyuan" to Panonychus citri, in the meanwhile, investigated the influence of "Lvmanyuan" on three kinds of spiders, Ebrechtella tricuspidata, Oxyopes sertatus and Pardosa pseudoannulata. The results showed that the toxicity of 16% "Liimanyuan" to P. Citri was the strongest when diluted by 18. 75 times, and the mortality could reach 99.0% after 72 h treated by the pesticide. 48 h after treatment, the linear regression equation of " Lümanyuan" to P. Citri was y=5.175 6+1. 183 8x, LC50=0. 710 6 mg/Ml. "Liimanyuan" was non-toxic to E. Tricuspidata and O. Sertatus, but it had a strong toxicity to P. Pseudoannulata, actually. The mortality of P. Pseudoannulata can reach 70% after 24 h treated by the 75 times diluted pesticide.%采用玻片粘胶浸渍法测定“绿满园”水剂对柑桔红蜘蛛Panonychus citri的生物活性,同时采用浸渍法测定“绿满园”水剂对三突花蛛、斜纹猫蛛和拟环纹豹蛛3种蜘蛛的毒力.结果表明,16%“绿满园”水剂18.75倍稀释液对红蜘蛛毒性最强,处理72 h后红蜘蛛死亡率可达99.0%.受药48 h后,“绿满园”对红蜘蛛的毒力回归方程为y=5.175 6 +1.183 8x,致死中浓度LC50为0.710 6 mg/mL.16%“绿满园”水剂对三突花蛛和斜纹猫蛛无毒性,但对拟环纹豹蛛有较强的毒性,75倍稀释液处理过的拟环玟豹蛛24 h后死亡率可达70%.

  1. 亚洲柑橘木虱2株高致病力病原真菌菌株的筛选%Screening two entomopathogenic fungal strains with high virulence against Asia citrus psyllid,Diaphorina citri

    Institute of Scientific and Technical Information of China (English)

    代晓彦; 李翌菡; 许炜明; 沈祖乐; 黄振; 吴建辉; 任顺祥; 邱宝利

    2016-01-01

    【目的】筛选对亚洲柑橘木虱Diaphorina citri Kuwayama具有高致病力的真菌菌株,为其微生物农药的研发奠定基础。【方法】测定5株球孢白僵菌Beauveria bassiana(菌株A~E)和5株玫烟色棒束孢菌Isaria fumosorosea菌株(菌株A~E)的生长速率、产孢量以及对木虱若虫的侵染致死率等,并进行比较分析。【结果】5株球孢白僵菌培养10 d后产孢量存在较大差异,A菌株的产孢量最少(7.96×107 mL-1),E菌株的产孢量最多(3.78×108 mL-1),两者差异显著;在喷施球孢白僵菌孢子1×106 mL-17 d后,对柑橘木虱低龄若虫的致死率与对照差异不显著,以A菌株的致死率最高(78.0%), E 菌株次之(77.0%)。5株玫烟色棒束孢菌株培养10 d 后, B 菌株产孢量最多(6.04×108 mL-1),E菌株的最少(6.28×107 mL-1),两者差异显著;在喷施玫烟色棒束孢孢子1×106 mL-17 d后,除D菌株外,其他制剂对亚洲柑橘木虱低龄若虫的致死率均显著大于对照, B菌株的致死率最高(81.0%)。【结论】综合考虑产孢量及致病力等指标,球孢白僵菌E菌株和玫烟色棒束孢B菌株是具有良好研发前景的柑橘木虱生物防治高致病力优良菌株。%[Objective] To screen entomopathogenic fungal strains with high virulence against Asia citrus psyllid ( ACP) , Diaphorina citri Kuwayama, and to provide a basis for development of microbial pesticide against ACP. [Method]The growth and sporulation rates of five Beauveria bassiana strains numbered A to E and five Isaria fumosorosea strains numbered A to E, and the mortality rates of ACP after infected by these ten fungal strains were investigated. [Result] The spores quantity of five B. bassiana strains were significantly different after cultured for 10 days, strain E had the largest spores quantity ( 3. 78 × 108 mL-1 ) and strain A had the least spores quantity(7. 96 × 107 mL-1 ). There was significant difference of spores quantity between strain E and

  2. 辐照对不同虫态柑橘全爪螨杀灭效果的研究%Study on elimination effect of irradiation against different stages of citrus red mites(Panonychus citri Mcgregor)

    Institute of Scientific and Technical Information of China (English)

    朱富伟; 邓乐晔; 翁群芳; 胡美英

    2012-01-01

    【Objective】 The experiment was to study elimination effects of irradiation against different stages citrus red mite(Panonychus citri Mcgregor) and to conform the effective dosage in order to achieve inspection and quarantine.【Method】 The eggs,larvae,protonymphs of citrus red mite were selected and irradiated by gamma irradiation(0,100,200,300,400 Gy),while adults were at the dosage of 0,200,400,600 and 800 Gy).The effect of irradiation against hatching rates and mortality of different stages of citrus red mites was studied.【Result】 It was found that after being irradiated at the dosage of 200 Gy,the 24 h-old eggs of citrus red mites were not hatched,so the gamma irradiation at the dosage of 200 Gy obviously had lethal effect on the eggs.After irradiated at the dosage of 400 Gy,the mortality of the larvae was as high as 96%.Gamma irradiation among the 300-400 Gy made the larvae sterile and the dosage of 400 Gy was sterile dosage to the protonymphs of citrus red mite.The adults laid less eggs which did not hatch at more than dosage of 400 Gy.After 15 days,the mortality of adult mites irradiated at the dosage of 400-600 Gy was 100%;while irradiated at the dosage of 800 Gy,the mortality was 100% after 13 days.So the irradiation among the 400-800 Gy made the adults sterile or lethal.【Conclusion】 The gamma irradiation at the dosage 400 Gy made citrus red mite at different stages lethal or sterile.So the citrus fruits irradiated at 400 Gy could achieve quarantine treatment requirement.%【目的】研究辐照对不同虫态柑橘全爪螨(Panonychus citri Mcgregor)的杀灭效果,确定有效的辐照剂量,以达到检验检疫目的。【方法】用不同剂量Co60-γ射线辐照处理卵、幼螨、前若螨(0,100,200,300,400Gy)和成螨(0,200,400,600,800Gy),研究辐照强度对不同虫态柑橘全爪螨卵孵化率和成螨死亡率的影响。【结果】柑橘全爪螨24h卵经200Gy的γ射线辐照处

  3. Effects of different host plants, host plant maturity and intact host plants versus detached host plant stems on the survival of Diaphorina citri Kuwayama%不同离体寄主及其成熟度对亚洲柑桔木虱存活的影响

    Institute of Scientific and Technical Information of China (English)

    吴丰年; 岑伊静; 梁广文

    2015-01-01

    【目的】亚洲柑桔木虱Diaphorina citri Kuwayama的虫口密度及活动与柑桔黄龙病的田间传播、流行有十分密切的关系,寻找合适的室内饲养条件能够便于观察和研究其生物学特性和传病机制。【方法】本文以九里香Murraya exotica (L.) Mant.、酸桔Citrus sunki Hort. ex Tanaka和马水桔Citrus reticulata Blanco. cv. Mashuiju 3种寄主植物不同成熟度离体梢为研究材料,(1)比较亚洲柑桔木虱卵分别在3种寄主植株和离体嫩梢上的孵化率;(2)比较3种寄主不同成熟度离体梢对各龄若虫存活率和蜕皮的影响;(3)比较3种寄主不同成熟度离体梢对成虫存活率的影响。【结果】(1)亚洲柑桔木虱在植株嫩梢上卵的孵化率高于离体嫩梢,九里香表现最明显;(2)低龄若虫在叶片未完全展开的离体嫩梢上存活率最高,而高龄若虫在完全展开的嫩梢上最高;(3)用离体成熟梢饲养柑桔木虱成虫存活率高于离体嫩梢,酸桔和马水桔离体梢饲养的存活率较九里香高。【结论】用寄主植物离体梢饲养的亚洲柑桔木虱卵孵化率和若虫、成虫存活率都较高而且较稳定,该方法可用于这种木虱的室内繁殖中。%Objectives] The density and movements of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) are strongly associated with the spread and epidemics of Huanglongbing (HLB). Finding suitable conditions for rearing D. citri are essential for observation of the biological characteristics of, and research on, the HLB transmission mechanism. [Methods] Entire host plants and detached shoots of 3 host species, Murraya exotica (L.) Mant., Citrus sunki Hort. ex Tanaka and Citrus reticulata Blanco. cv. Mashuiju at different stages of maturity were used as host materials to compare the effects of these treatments on 1) psyllid egg hatch rate, 2) the survival and molting of psyllid nymphs, 3) the survival of psyllid adults

  4. Rapid characterization of 96 chemical constituents in Citri Reticulatae Folium (leaves of ‘Fuju’) using HPLC-DAD-ESI-MSn%HPLC-DAD-ESI-MSn技术对橘叶(福橘叶)中96个化学成分的快速分离和鉴定

    Institute of Scientific and Technical Information of China (English)

    曹规划; 付庆荣; 张藏曼; 王弘; 陈世忠

    2016-01-01

    为了对橘叶(福橘叶)中的化学成分进行较为系统地研究,我们首次采用液质联用技术((HPLC-DAD-ESI-MSn)系统地分离和鉴定了橘叶中的化学成分.最终,我们在橘叶中解析了96个化学成分,包括:31个酚酸类化合物,4个黄酮苷元,6个黄酮单氧苷,10个黄酮双氧苷,5个黄酮单碳苷和5个黄酮双碳苷化合物,以及6个黄酮碳氧苷,5个3-羟基-3-甲基戊二酰基取代的黄酮苷,1个黄烷-3-醇和2个生物碱类化合物,并且初步鉴定出了21个多甲基黄酮类化合物(PMFs).在上述解析的96个化合物中,52个化合物为首次在橘叶中发现,15个化合物为首次在柑橘属植物中发现.同时,我们在橘叶中也发现了9个潜在的新化合物.%In order to systematically investigate the chemical constituents of Citri Reticulatae Folium (leaves of ‘Fuju’),an analytical method that included high-performance liquid chromatography,diode array detection,electrospray ionization,and ion-trap time-of-flight mass spectrometry (HPLC-DAD-ESI-MSn) was used to separate and identify the individual chemical components of Citri Reticulatae Folium.As a result,96 compounds were tentatively identified in this study:including 31 phenolic acids,4 flavonoid aglycones,6 flavonoid mono-O-glycosides,10 flavonoid-O-diglycosides,5 flavonoid mono-C-glycosides,5 flavonoid di-C-glycosides,6 flavonoid O,C-glycosides,5 (3-hydroxy-3-methylglutaryl) glycosyl flavonoids,1 flavan-3-ol,and 2 alkaloids.In addition,21 polymethoxy flavonoids (PMFs) were identified in this paper.Among these compounds,52 compounds,which were previously found in other Citrus plants,have been identified for the first time in Citri Reticulatae Folium.15 compounds have not been previously found in the Citrus genus were identified.Moreover,9 potentially new compounds have also been detected in this paper.This is the first report of the full characterization of chemical components of Citri Reticulatae Folium (leaves of

  5. 25%JS7119乳油对桔全爪螨的生物活性和田间防效%Bioactivity assay and control effect of the new active compounds 25% JS7119 EC for different developmental insect stages of Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    刘浩强; 李鸿筠; 冉春; 胡军华; 姚廷山; 岳健苏; 李晓娇

    2011-01-01

    测定25%JS7119乳油对不同虫态桔全爪螨的生物活性和田间防效.活性测定结果表明,25%JS7119乳油对桔全爪螨成虫的玻片浸渍法的致死中浓度(LC50)为115.921 7 mg/kg,大于对照药剂5%唑螨酯悬浮剂和15%哒螨灵乳油的致死中浓度;叶片浸渍法的LC50值为0.639 4 mg/kg,大于15%哒螨灵乳油的LC50,小于5%唑螨酯悬浮剂的LC50.25%JS7119乳油对桔全爪螨若虫和卵的叶片浸渍法的LC50值分别为4.478 3和644.391 7 mg/kg,均大于5%唑螨酯悬浮剂和15%哒螨灵乳油的LC50.田间防效测定结果表明,25%JS7119乳油625倍液对桔全爪螨速效性较好,持效期15d左右,与15%哒螨灵乳油1 500倍液的防效基本相当.%This experiment studied bioactivity and control effect of the 25%JS7119 EC for different developmental insect stages of Panonychus crtri(McGregor). The results of bioactivity assay showed that active compounds 25%JS7119 EC for Panonychus citri adults of the slide dipmethod, the median lethal dose (LC50) was 115.921 7 mg/kg. It was higher than the LC50 of the reference pesticides 5% fenpyroximate SC and 15% ridaben EC. The results of bioactivity assay showed that active compounds 25%JS7119 EC for Panonychus citri adults of the leaves-tip bioassays, the LC50 was 0.639 4 mg/kg . It was higher than the LC50 of the reference pesticides 15% ridaben EC. It was lower than the LC50 of the reference pesticides 5% fenpyroximate SC. The results of bioactivity assay showed that active compounds 25%JS7119 EC for Panonychus citri nymphs and egges apply the leaves-tip bioassays, the LC50 respectively was 4.478 3 mg/kg and 644.391 73 mg/kg. The LC50 of they both were higher than the reference pesticides 5% fenpyroximate SC and 15% ridaben EC. But the control effect of 25%JS7119 EC in field showed 25%JS7119 EC 625 times was better and more lasting to Panonychus citri the control effect of 25% JS7119 EC 625 times was equivalent to 15% ridaben EC 1 500 times, the

  6. Supercooling points and freezing points of Diaphorina citri Kuwayama and Cacopsylla citrisuga Yang & Li%亚洲柑橘木虱和柚喀木虱过冷却点和体液结冰点测定

    Institute of Scientific and Technical Information of China (English)

    黄治轶; 徐昊昱; 杜源良; 杨玉枝; 乌天宇; 曾丽霞; Yu-LuXIA; 岑伊静

    2015-01-01

    亚洲柑橘木虱Diaphorina citri Kuwayama和柚喀木虱Cacopsylla citrisuga Yang&Li均为柑桔上的重要害虫,前者为黄龙病的主要媒介昆虫,后者也已证实为黄龙病菌的携带者.本文对这两种木虱各龄若虫和成虫的过冷却点和体液结冰点进行了测定,结果表明,柑橘木虱过冷却点和冰点均以1龄若虫最低,平均值分别为-26.32℃和-26.22℃;成虫的过冷却点和冰点最高,分别为-19.60℃和-18.71℃;其它虫态过冷却点和冰点由低到高依次为2龄若虫、4龄若虫、5龄若虫、3龄若虫.柚喀木虱过冷却点和冰点也均以1龄若虫最低,平均值分别为-25.30℃和-25.08℃;5龄若虫的过冷却点和冰点最高,平均分别为-19.50℃和-17.69℃;其它虫态过冷却点和冰点由低到高依次为2龄若虫、3龄若虫、4龄若虫、成虫.两种木虱的比较结果表明,各发育阶段的表现不一致,柚喀木虱的3龄若虫和成虫过冷却点显著低于柑桔木虱,而4龄、5龄若虫则显著高于柑桔木虱;3龄若虫体液结冰点也显著低于柑桔木虱,但1龄、4龄却显著高于柑桔木虱.柑桔木虱雌雄成虫的过冷却点和体液结冰点差异不显著.研究结果表明两种木虱的过冷却点、体液结冰点都较低,因而可能具有较强的耐寒能力.

  7. Selection, Identification and Culture Characteristics of a Highly Virulent Strain of Beauveria towards Sympiezomias citri%柑橘灰象甲一株高毒力白僵菌菌株的筛选鉴定及培养特性

    Institute of Scientific and Technical Information of China (English)

    王定锋; 黎健龙; 王庆森; 李慧玲; 吴光远

    2014-01-01

    柑橘灰象甲Sympiezomias citri Chao是一种重要的农业害虫,可危害多种经济作物,而当前对其防治主要还是以化学防治为主。为寻找一种高效、安全和可持续的防治方法,本研究从15株白僵菌菌株中筛选到一株对柑橘灰象甲成虫高毒力的菌株Bb2-1。室内生测结果表明,利用1.0×108孢子/mL菌株Bb2-1孢悬液处理(26℃)柑橘灰象甲成虫的LT50值为3.77 d;处理7 d,柑橘灰象甲累计校正死亡率为100%,僵虫率为97.78%;其LC50值为4.55×104孢子/mL。综合菌株的培养性状、形态特征和rDNA ITS序列分析将菌株Bb2-1确定为球孢白僵菌Beauveria bassiana。通过测定菌落直径和产孢量,研究了5种培养基类型(PDA、PPDA、1/4 SDAY、SDAY和Czapek)、5个温度梯度(15、20、25、30和35℃)、7个不同pH值(pH 4.0~10.0)和7种光照条件(0L:24D、24L:0D、18L:6D、12L:12D、6L:18D、先黑暗7 d后光照7 d和先光照7 d后黑暗7 d)对菌株Bb2-1菌丝生长和产孢量的影响。结果表明,SDAY培养基、25℃的培养温度和培养基 pH 值7.0对菌株菌落生长和产孢最有利。此外,虽然光照时间对菌株生长速率影响不大,但充分的光照时间是提高产孢量的保证。柑橘灰象甲高毒力的球孢白僵菌菌株的筛选及其培养特性的研究,将为今后大规模生产该菌来防治柑橘灰象甲提供参考。%Sympiezomias citri (Coleoptera:Curculionidae) is one of the most important agricultural pests causing great damage on various economic crops, and chemical control is the usual treatment method for this beetle at present. In order to explore alternative strategy for sustainable control of the pest population, the virulence of 15 strains of Beauveria spp. to S. citri was tested under laboratory condition. The strain Bb2-1 was selected for the most virulent to the adults of S. citri, and caused the highest corrected mortality of 100

  8. Study on the cooperative control effect of mineral oil and Neoseiulus barkeri on Panonychus citri%矿物油乳剂与巴氏新小绥螨对柑橘全爪螨的协同控制研究

    Institute of Scientific and Technical Information of China (English)

    方小端; 欧阳革成; 卢慧林; 刘慧; 张宝鑫; 郭明昉; 吴伟南

    2012-01-01

    利用捕食螨防治柑橘全爪螨Panonychus citri已有大面积应用,但捕食螨田间防治效果常受到果园使用化学农药的影响,相应配套技术是捕食螨应用的瓶颈问题.2010年6 ~ 10月,在广东省四会市罗源镇柑橘园,分别采用五种处理方式(常规化学农药;化学农药加巴氏新小绥螨Neoseiulus barkeri;单独使用矿物油乳剂;单独使用巴氏新小绥螨;矿物油乳剂加巴氏新小绥螨)防治柑橘全爪螨,设不采取任何防治措施的样地为对照.试验结果显示,各处理的种群干扰控制指数分别是3.7195、1.4942、0.2439、0.2053、0.0488,校正虫口减退率分别是-271.95%、-49.42%、75.61%、79.47%、95.12%.化学农药防治对柑橘全爪螨的控制作用不理想,影响了巴氏新小绥螨的持续控制作用;巴氏新小绥螨能较好地发挥对柑橘全爪螨的控制作用,矿物油乳剂表现出较好的长期控制效果,矿物油乳剂配合巴氏新小绥螨对柑橘全爪螨有较好的协同控制作用.%The field application of predatory mites for controlling Panonychus citri usually was non-ideal due to the usage of chemical pesticides. The experiments were carried out in a citrus orchard in Sihui City, Guangdong Province, during June to October 2010. Five treatments were set, including (1) chemical pesticides spraying; ( 2 ) chemical pesticides spraying and Neoseiulus barken releasing; ( 3 ) mineral oil spraying only; (4) N. barkeri releasing only; (5) mineral oil spraying and N. barkeri releasing. No treatment as control. The interference index of population control was 3.7195, 1.4942, 0.2439, 0. 2053 , 0. 0488, and the corrected-population-falling-rate was - 271. 95% , - 49. 42% , 75. 61% , 79. 47% , 95. 12% respectively. The results demonstrate that mineral oil and N. barkeri alone provide better control effect than the traditional chemical control on P. citri. And the control effect of mineral oil combining with predatory mites

  9. Control efficacy against Geotrichum citri-aurantii and effects on postharvest storage quality of Ponkan fruit by combining thyme oil with sodium carbonate%百里香精油与碳酸钠结合对桠柑酸腐病的防治效果及品质的影响

    Institute of Scientific and Technical Information of China (English)

    刘霞; 方伟文; 李祎晨; 余挺; 郑晓冬

    2010-01-01

    研究百里香精油(thyme oil)与不同浓度的碳酸钠(Na_2CO_3)结合使用对桠柑果实采后酸腐病(Geotrichum citri-aurantii)的防治及对其贮藏品质的影响.结果表明:百里香精油与Na_2CO_3结合使用对桠柑果实酸腐病害有显著的防治效果,当1600 μL·L~(-1)的百里香精油与0.5% Na_2CO_3结合使用时能够完全抑制桠柑酸腐病害的发生;400 μL·L~(-1)的百里香精油与1% Na_2CO_3结合使用使桠柑酸腐病害发病率降低了60%,且处理后对桠柑果实的硬度、抗坏血酸含量、可滴定酸含量和可溶性固形物含量均无显著影响.

  10. The selectivity of Diaphorina citri to Carmona microphylla and Rutaceae hosts, and its tolerance to starvation and thirstiness%柑橘木虱对福建茶和芸香科植物的选择性及其耐饥渴能力

    Institute of Scientific and Technical Information of China (English)

    王辉; 丁芳; 钟云; 姜波; 易干军; 王国平

    2011-01-01

    柑橘木虱Diaphorina citri(Kuwayama)是柑橘的重要害虫,也是传播柑橘黄龙病菌的唯一昆虫媒介,给柑橘生产造成很大损失.相关研究表明,芸香科Rutaceae植物是柑橘木虱的主要寄主[1].受全球性暖冬气候的影响,木虱的生存空间和寄主范围逐渐扩大[2],导致黄龙病大面积发生.国内外对柑橘木虱生物学特性、逆境耐受性等做过一些研究[3].而关于柑橘木虱耐饥渴能力和寄主选择性的报道较少,为此,作者选取7种常见的芸香科植物,在室外条件下研究柑橘木虱对各种寄主的选择性,并在室内条件下检测其耐饥渴能力,以期为柑橘木虱的综合防治提供参考.

  11. Selective toxicity of some acaricides commonly used in citrus orchards to Amblyseius barkeri and Panonychus citri%橘园常用杀螨剂对巴氏钝绥螨和柑橘全爪螨的选择毒性

    Institute of Scientific and Technical Information of China (English)

    肖顺根; 余丽萍; 舒畅; 钟玲; 李爱华; 夏斌

    2010-01-01

    采用FAO(1980)推荐的玻片浸溃法,在室内测定了几种橘园常用杀螨剂对巴氏钝绥螨(Amblyseius barkeri)的毒力,并筛选出其中毒性较弱的5种杀螨剂对柑橘全爪螨(Panonychus citri)进行了毒力测定.结果表明:二甲基二硫醚、阿维菌素、甲氰菊酯等对巴氏钝绥螨有较强的毒力,橘园释放巴氏钝绥螨时,不推荐使用.5种杀螨剂对巴氏钝绥螨和柑橘全爪螨的选择性毒性为:石硫混合剂>哒螨灵>三唑锡>阿维·炔螨特>炔螨特,其中石硫合剂和哒螨灵的毒性选择指数为230.522和144.806,均介于100~1 000,为高度正向选择性,表明石硫合剂、哒螨灵是用于协调化学防治与生物防治较理想的药剂.

  12. 柑橘全爪螨酚氧化酶原激活酶基因cDNA克隆及生物信息学分析%Cloning and bioinformatic analysis of the citrus red mite, Panonychus citri, prophenoloxidase activating enzyme gene

    Institute of Scientific and Technical Information of China (English)

    钟锐; 丁天波; 廖重宇; 张昆; 豆威; 王进军

    2013-01-01

    Prophenoloxidase, a member of the serine proteinase group, is a key enzyme in invertebrates for defense against microbial infections and the prophenoloxidase activating enzyme ( PPAE) is an important component of the prophenoloxidase activating system ( PPO-AS). A full-length cDNA of the PPAE gene named PcPPAE ( GenBank: KC136292) was cloned from Panonychus citri (McGregor) using rapid amplification of cDNA ends (RACE). The cloned gene was 1 676 bp in length with an ORF of 1 377 bp encoding 458 amino acid residues. The protein predicted from the cloned PcPPAE had a molecular weight of 49.9 ku and a theoretical isoeletric point (pI) of 5.68. Its predicted molecular formula was C2201H3467 N607O678 S22. Bioinformatic analysis showed that its instability index was 41.51 and its GRAVY was -0.268. The deduced protein PcPPAE had a clip-domain, serine proteinase domain and a conserved catalytic triad in the serine protease domain. Phylogenetic analysis indicates that PcPPAE is most closely related to the clip-domain serine proteinase of Tetranychus urticae ( Koch) . These results provide the basis for further research on defense against microbial infection in the citrus red mite.%酚氧化酶原激活酶(prophenoloxidase activating enzyme,PPAE)是酚氧化酶激活系统(prophenoloxidase activating system,PPO-AS)的组成部分,是无脊椎动物抵御入侵微生物的关键酶.本研究利用RACE技术从柑橘全爪螨Panonychus citri (McGergor)体内获得一条PPAE基因全长cDNA,命名为PcPPAE(GenBank:KC136292),属于丝氨酸蛋白酶家族.该基因cDNA全长1 676 bp,开放阅读框1 377 bp,编码458个氨基酸.该基因编码蛋白预测分子量为49.9 ku,理论等电点(pI值)为5.68,分子式为C2201 H3467 N607 O678 S22,不稳定系数为41.51,总亲水性系数为-0.268.经序列比对发现该基因具有发夹结构域,丝氨酸蛋白酶结构域,以及丝氨酸蛋白酶结构域中保守的催化三联体.系统发育分析表明该基

  13. Susceptibility to acaricides and detoxification enzyme activity of four field populations of Panonychus citri%柑橘全爪螨田间种群敏感性测定及三种主要解毒酶活性比较

    Institute of Scientific and Technical Information of China (English)

    丁天波; 牛金志; 夏文凯; 孙倩倩; 豆威; 王进军

    2012-01-01

    The susceptibility of four Chongqing populations of the citrus red mite Panonychus citri ( McGregor) to four commonly used acaricides, abamectin, azocyclotin, pyridaben and spirodiclofen, was investigated. The results show that all four populations were least sensitive to azocyclotin, with LC50 values ranging from 209. 9 to 370. 9 mg/L, relative to the other three acaricides. The Bishan population exhibited the highest level of sensitivity to abamectin; LC50 values of the Wulong and Zhongxian populations were 12-and 11-times higher than that of Bishan population. Although the Beibei population had significantly higher resistance to pyridaben, it had a low LC50 value to spirodiclofen. Investigation of the activities of the main detoxification enzymes ( cytochrome P450 momooxygenases, glutathione S-transferase, carboxylesterase) indicated that there was no significant correlation between resistance levels and detoxification enzyme activity. These could possibly be caused by different strategies of applying acaricides in the field, differences in mode of action between different acaricides and different resistance mechanisms in the four populations.%为明确重庆地区柑橘全爪螨Panonychus citri (McGregor)对常用杀螨剂的抗性水平,本研究采用阿维菌素、哒螨灵、三唑锡、螺螨酯4种不同类型杀螨剂对柑橘全爪螨重庆北碚种群、璧山种群、武隆种群和忠县种群进行了田间敏感性测定.结果表明,柑橘全爪螨4个种群对三唑锡表现最不敏感,致死中浓度LC50在209.9 ~370.9mg/L之间.璧山种群对阿维菌素敏感性最高,武隆种群和忠县种群对阿维菌素的相对抗性分别达12倍和11倍.哒螨灵监测结果表明,北碚种群的抗性水平显著高于其他3个种群.而北碚种群对螺螨酯的LC50仅为1.2 mg/L,显著低于其他种群.柑橘全爪螨4个种群解毒酶活性研究发现,解毒酶活性的高低与不同种群抗性水平之间并没有明显相关性,这

  14. Selection of resistance to amitraz and analysis of expression difference of cytochrome P450 genes in Panonychus citri (Acari: Tetranychidae)%橘全爪螨对双甲脒的抗性选育及其P450基因的表达差异分析

    Institute of Scientific and Technical Information of China (English)

    冉春; 江高飞; 刘斌; 刘浩强; 李鸿筠; 王进军

    2012-01-01

    To evaluate the resistance risk of Panonychus citri to amitraz and clarify the relationship between expression level of cytochrome P450 gene and resistance of P. citri, resistance selection was conducted in the laboratory, and cross-resistance of the amitraz-resistant strain was studied with slide-dip method and cytochrome P450 gene expression profiles between the resistant strain and the susceptible strain were compared using RPKM (reads per kb per million reads) method. After selection with amitraz continuously for 12 generations, a resistant strain was obtained with the resistance ratio (R/S) of 26. 32 compared with the susceptible strain. The realized heritability of resistance to amitraz was 0. 148. Bioassay data showed that the amitraz-resistant strain had positive cross-resistance to spirodiclofen, diafenthiuron, propargite and azocyclotin (the R/S ratio was 16. 85, 4. 98, 2. 13, and 2. 05, respectively), but had no cross-resistance to abamectin, fenbutatin oxide, pyridaben and petroleum oil (the R/S ratio was 1. 10, 1. 21, 0. 67 and 0. 99, respectively). Gene expression difference analysis results indicated that 16 cytochrome P450 genes were up-regulated and 27 cytochrome P450 genes were down-regulated in the resistant strain. CYP389A6 [ log2ratio ( RS/SS) =11.526] and CYP389A2 [ log2 ratio(RS/SS) = -12.683] were the top up-regulated and down-regulated genes, respectively, which are very likely to be associated with the resistance of P. citri to amitraz.%为了对双甲脒进行抗性风险评估,弄清P450基因在橘全爪螨Panonychus citri抗药性中的作用,在室内用双甲脒对橘全爪螨进行了抗性选育和交互抗性研究,同时分析了橘全爪螨双甲脒抗性和敏感品系P450基因表达差异.经过12代抗性选育,获得了橘全爪螨双甲脒抗性品系,与敏感品系比较,橘全爪螨对双甲脒的抗性倍数达到26.32倍.抗性风险评估表明,橘全爪螨对双甲脒抗性遗传力h2为0.148.螺螨酯、丁醚脲

  15. Study on the active components of oviposition repellency of Mikania micrantha H.B.K.against citrus red mite, Panonychus citri McGregor%薇苷菊提取物对桔全爪螨的产卵驱避作用及有效组分分析

    Institute of Scientific and Technical Information of China (English)

    岑伊静; 庞雄飞; 凌冰; 孔垂华

    2004-01-01

    使用甲醇、乙酸乙酯、乙醚提取薇苷菊Mikania micrantha H.B.K.地上部植株并测试3种提取物对桔全爪螨Panonychus citri McGregor产卵的驱避作用,结果发现这些提取物处理后1d都有显著的产卵驱避效果,其中极性最强的甲醇提取物效果最好,处理后1d的产卵驱避率为74.22%.用乙醚、乙酸乙酯、正丁醇、水依次对薇苷菊甲醇提取物进行萃取,生测结果表明只有极性最强的水萃取物具有显著的产卵驱避效果.进一步研究发现薇苷菊甲醇提取物经柱层析分离得到的6个组分中有3个对桔全爪螨有显著的产卵驱避作用,但效果都不及提取物,说明薇苷菊对桔全爪螨的产卵驱避作用是各组分共同作用的结果.用GC-MS对最有效组分的分析表明:2,2′-亚甲基双(6-叔丁基-4-甲基)苯酚是含量最大的成分,占70.24%,β-谷甾醇和岩藻甾醇也是有效成分,但含量较低,分别占12.03% 和 5.61%.

  16. Pesticide susceptibility and carboxylesterase activity in two field populations of Panonychus citri(Acari: Tetranychidae)%柑橘全爪螨两个田间种群抗性监测及羧酸酯酶生化特性研究

    Institute of Scientific and Technical Information of China (English)

    张昆; 丁天波; 杨爵铭; 豆威; 王进军

    2013-01-01

    采用叶碟浸渍法测定了重庆北碚和万州地区柑橘全爪螨Panonychus citri(McGregor)田间种群对阿维菌素、毒死蜱、甲氰菊酯和哒螨灵的抗性水平.结果表明,同室内敏感品系相比,北碚种群对毒死蜱、甲氰菊酯和哒螨灵的相对抗性水平分别达到3倍、3倍和22倍;万州种群对阿维菌素、毒死蜱、甲氰菊酯和哒螨灵的相对抗性水平分别达到2倍、35倍、10倍和2倍.柑橘全爪螨2个地理种群的羧酸酯酶CarE的生化特性研究发现,CarE酶活的增高和毒死蜱的抗性存在一定的相关性.毒死蜱对不同地理种群柑橘全爪螨CarE的抑制效果不同,对抗性倍数较高的万州种群抑制效果最差.%Samples from two populations of the citrus red mite collected from citrus orchards were assayed for susceptibility to abamectin, chlopyrifos, fenpropathrin and pyridaben. The results indicate that the Beibei population displayed a 3-, 3- and 22-fold resistance ratio, respectively, to chlopyrifos, fenpropathrin and pyridaben compared to a susceptible strain. The Wanzhou population exhibited a 2-, 35-, 10- and 2-fold resistance ratio, respectively, to the same pesticides. Enhancement of CarE activity was involved in resistance to chlopyrifos in both populations. Inhibition of chlopyrifos activity differed between the two mite populations and was stronger in the Wanzhou population than the susceptible strain.

  17. A Study on the Control Technologies for 4 Kinds of Natural Pesticides against Panonychus citri (McGregor) in Organic Citrus Orchard%4种天然源农药对有机橘园柑橘全爪螨的防治技术研究

    Institute of Scientific and Technical Information of China (English)

    熊忠华; 席运官; 陈小俊; 刘明庆

    2013-01-01

    In order to illustrate the control efficacy of azadirachtin, matrine, rotenone and SK EnSpray99 against Panonychus citri (McGregor) in the background of organic management, the field experiments were conducted by one and two field sprays. With one spray, 2 000 times solution of 0. 6% matrine AS got the quickest response with a control efficacy of 98. 57% 1 d after the spray. Among the 4 pesticides tested, only azadirachtin had an increasing effect during the trial. Azadirachtin had better control effects than others with a control efficacy of 97.54% 21 d after the treatment, and SK EnSpray99 was secondary whose control efficacy was higher than that of matrine, rotenone and abamectin ( control pesticide). With two sprays, azadirachtin, matrine, and SK EnSpray99 had control efficacy above 96.69% , while 800 times emulsion of 2.5% rotenone EC had lower control efficacy than others, its control efficacy was 88. 95% -92. 17%. Furthermore, the control efficacy of azadirachtin, matrine, and SK EnSpray99 against Panonychus citri was better than or the same as that of abamectin. It could be concluded that 4 kinds of natural pesticides tested had excellent control effect on phytophagous mites in organic citrus orchards, and two sprays were better than one spray.%为明确有机管理背景下印楝素、苦参碱、鱼藤酮和SK绿颖农用喷洒油4种经过有机论证的天然源药剂对柑橘全爪螨的防效,进行了4种供试药剂一次喷雾施药和二次喷雾施药两种处理防治柑橘全爪螨的田间试验.一次施药处理结果表明,0.6%苦参碱水剂2 000倍液的速效性最好,药后1d对柑橘全爪螨的防效为98.57%,显著高于其他药剂;4药剂中,仅0.5%印楝素乳油1 000倍液的防效在供试期间内呈现逐渐上升的趋势,其余3药剂在施药3d后的防效均逐步下降;药后21 d印楝素的防效较其他药剂显著为高,达97.54%,其次为SK绿颖农用喷洒油,再次为苦参碱、鱼藤酮和对照药

  18. Development of RLK-Derived Molecular Markers Associating with the Resistance to Citrus Canker [Xanthomonas axonopodis pv. Citri (Xac)] Disease%开发与柑桔抗溃疡病基因连锁的由RLK-RGC衍生的分子标记

    Institute of Scientific and Technical Information of China (English)

    向旭; 郑启发; 黄舒; 陈存贤; Frederick G. Gmitter Jr.; 邓占鳌

    2005-01-01

    本文是在先期研究工作的基础上,利用从柑桔与枳属间杂种的基因组DNA所获得的类受体激酶(RLK)的候选抗病基因序列,重新设计引物,对柑桔抗溃疡病材料和感病材料开展以PCR扩增为基础的对比分析,其中一对引物‘19h16/DdeI'的扩增产物经限制性内切酶DdeI酶切,揭示了抗性材料(Ichang Papeda,Meiwa kumquat,Maruhi kumquat and Nagami kumquat)和感病材料(Flying Dragon,Valencia orange and Palestine sweetlime)之间的多态性差异,同时,在C.Ichangensis的自交F1代和Palestine sweetlime× Ichang Papeda的杂交F1代群体中也见明显的多态性差异;对这些F1代个体进行溃疡病病原[Xanthomonas axonopodis pv.Citri(Xac)]接种作抗病性表型鉴定,结果表明,该分子标记‘19h16/DdeI'与柑桔溃疡病抗性密切相关;经纯化测序的结果进一步证明,抗性材料PCR扩增产物具有完全一致的序列和DdeI酶切位点,但感病材料缺少这一DdeI酶切位点;染色体步行(primerwalking)在BAC文库的对应单克隆中获得了一个完整的抗病基因序列,与以前获得的2个抗病基因序列‘17o6RLKP'和‘26m19RLKP'相比,‘19h16RLKP'也具有Xa21抗病基因蛋白的所有特征,包括含有一个信号肽、同样数目的亮氨酸重复序列、跨膜域和激酶域等.基于该序列的开放读码框,发展了特异性更强可靠性更高的另一分子标记,在今后的研究工作中具有较大的应用潜力.%By utilizing the receptor-like kinase (RLK) RGC sequences previously obtained from the genomic DNA of an intergeneric Citrus and Poncirus hybrid, PCR amplification with one pair of new-designed primers was found to reveal polymorphism between the theoretical resistant species (Ichang Papeda, Meiwa kumquat,Maruhi kumquat and Nagami kumquat) and susceptible species (Flying Dragon, Valencia orange and Palestine sweet lime ) and among the self-crossing population of C. Ichangensis and F1 population of Palestine sweet lime

  19. 柑橘木虱两地理种群的内共生菌群落组成及传菌能力%The endosymbiotic microbiota of two geographical populations of the Asian citrus psyllid,Diaphorina citri,in China and its ability of pathogen transmission

    Institute of Scientific and Technical Information of China (English)

    马晓芳; 张学潮; 徐海君

    2012-01-01

    柑橘黄龙病(Huanglongbing,HLB)是经柑橘木虱Diaphorina citri传播的最主要柑橘病害之一,危害严重时能对柑橘产业造成毁灭性的破坏.为了鉴定福建和海南2个地理种群柑橘木虱的内共生菌群落组成,本研究对16SrRNA部分保守序列进行PCR扩增,并利用特异性引物对不同内共生菌进行了感染率检测;另外,还通过人工接虫的方法,探索柑橘木虱成虫在带黄龙病菌蕉柑Citrus reticulata cv.Tankan 上的获菌能力,以及带菌柑橘木虱成虫对黄岩蜜橘C.reticulata cv.Subcompress的传菌能力.研究发现,这2个地理种群的柑橘木虱含有相同的内共生菌组成,包括α-Proteobacteria,Wolbachia spp.,γ-Proteobacteria,mycetocyte symbionts,β-Proteobacteria,Oxalobacter 和β-Proteobacteria,Herbaspirillum,而且这2个地理种群柑橘木虱的4种内共生菌的携带率均在95%以上.柑橘木虱成虫在带菌蕉柑上饲菌28 d后,带菌率可达到82%,而带菌柑橘木虱成虫在黄岩蜜橘上传菌75 d后,可导致橘树整体带菌.本研究为柑橘木虱的进一步研究和防虫治病途径提供了一些理论依据.%Huanglongbing (HLB) is one of the most severe citrus diseases, which is usually transmitted by the Asian citrus psyllid ( Diaphorina citri), and causes great economic loss. To understand the endosyrnbiotic microbiota of the citrus psyllid from Hainan and Fujian provinces in China, the partial conserved region of 16S rRNA was amplified by PCR, and subsequently the infection rate of each endosymbiont from two geographical populations of the citrus psyllid was detected by PCR using specific primer pairs in this stduy. Moreover, we detected the acquisition efficiency of the pathogen by adult citrus psyllid reared on Citrus reticulata cv. Tank an infected with Candidatus Liberibacter as iatic us (CLas) , and the transmission efficiency to Citrus reticulata cv, Subcompress via CLas-positive psyllids. The results demonstrated that the two

  20. 联苯菊酯等6种农药对柑桔木虱成虫室内毒力测定及田间药效试验%Field Control Experiments and Toxicity of 6 Pesticides to Asian Citrus Psylla(Diaphorina citri Kuwayama)

    Institute of Scientific and Technical Information of China (English)

    邓明学; 谭有龙; 唐美欣; 陈贵峰; 唐明丽

    2009-01-01

    Citrus psylla (Diaphorina citri) has become the most important pest in Huanglongbing (HLB) areas. Up to now; the assay was yet not reported. By means of dipping, the laboratory toxicity of 6 pesticides to adult psylla was conducted out in 2008. The LC of carbosulfan, phenthoate,bifenthrin,imidacloprid, quinalphos,Piri-miphos-methyl was 4.1mg/kg, 44.3 mg/kg, 44.3 mg/kg, 60.1 mg/kg, 73.5 mg/kg, 192.8 mg/kg, respectively. Af-ter treating of 24 h, 3d and 7 d, the adult psyUid field control efficiency of bifenthrin plus azone 12.5 mg (a.i)/kg was all 100%. the adult psyllid control efficiency of phenthoate 333 mg(a.i)/kg,quinalphos 250 mg(a.i)/kg, carbo-suffan plus azone 200(a.i)/kg was all over than 95%, while that of pirimiphos-methyl 500 mg(a.i)/kg less 80%. The adult psyllid field control efficiency of carbosulfan plus azone 200(a.i)/kg was better than that of carbosul-fan 250(a.i)/kg.%为了筛选到更多防治柑桔木虱成虫的有效药剂,于2008年采用点滴法测定了6种农药对其成虫的室内毒力,活性最高的是丁硫克百威(LC50=4.1 mg/kg),其次分别是稻丰散(LC50=44.3 mg/kg)、联苯菊酯(LC50=44.3 mg/kg)、吡虫啉(LC50=60.1 mg/kg)和喹硫磷(LC50=73.5mg/kg),最差的是甲基嘧啶磷(LC50=192.8mg/kg).田间药效试验结果表明,增效联苯菊酯EC 25.00,16.67,12.50 mg(a.i)/kg药后24 h,3,7天的防效达100%;喹硫磷EC 250 mg(a.i)/kg、稻丰散EC 500 mg(a.i)/kg、333 mg(a.i)/kg、增效丁硫克百威EW200 mg(a.i)/kg药后24 h的防效>95%;甲基嘧啶磷500 mg(a.i)/kg的防效低于80%.增效丁硫克百威EW200mg(a.i)/kg的防效高于丁硫克百威EC 250mg(a.i)/kg的防效.

  1. Thymus vulgaris subsp. mansanetianus subsp. nov. (Lamiaceae)

    OpenAIRE

    Pedro Pablo Ferrer-Gallego; Albert J. Navarro Peris; Emilio Laguna Lumbreras; Gonzalo Mateo Sanz

    2013-01-01

    RESUMEN: Se describe una nueva subespecie de Thymus vulgaris L. (Lamiaceae); Th. vulgaris subsp. mansanetianus subsp. nov., caracterizada por presentar un hábito postrado, tallos estoloníferos, decumbentes y radicantes, hojas muy estrechas y una floración otoñal. ABSTRACT: Thymus vulgaris subsp. mansanetianus subsp. nov. (Lamiaceae). A new subspecies of Thymus vulgaris L. (Lamiaceae); Th. vulgaris subsp. mansanetianus subsp. nov. is described. This new subspecies is characterized by its prost...

  2. 冰糖橙与枸橼 C-05对溃疡病菌生长特性的影响%The Influence of ‘Bingtang’ Sweet Orange or Citron C-05 on the Growth Characteristics of Xanthomonas axonopodis pv. citri

    Institute of Scientific and Technical Information of China (English)

    葛红娟; 龙桂友; 戴素明; 李大志; 李娜; 邓子牛

    2015-01-01

    [Objective]A new inoculation method was used to discuss the difference of the influence of ‘Bingtang’ sweet orange and C-05 on the growth characteristics of Xanthomonas axonopodis pv. citri (Xac) by comparing different influences of leaves on Xac.[Method]The fully expanded leaves with light green of ‘Bingtang’ sweet orange and citron C-05 were sterilized by 75% ethyl alcohol and 1% NaClO, cut and cultured with Xac in the same petri dish to determine the influence of ‘Bingtang’ sweet orange or citron C-05 on the growth of Xac in MT medium or the NYGA medium replaced the middle place of the MT medium (MA). And the leaves’ solution of ‘Bingtang’ sweet orange or citron C-05 were extracted and added with 25%, 50%, and 75% to MT medium to determine the influence on the growth of Xac; also these were added with different ratios to NYGB medium to determine the content of extracellular polysaccharide (EPS) of Xac, respectively. [Result]The leaves of ‘Bingtang’ sweet orange promoted the growth of Xac on MT medium. The proliferation of the strain could be viewed after 1 week, the average diameter of Xac was 0.5 mm larger than CK. After 2 weeks, the average diameter of Xac was 5.27 mm, which was the 3 times of that of CK. From 2 to 3 weeks was the rapid growth stage of Xac, the average diameter of Xac was from 5.27 mm to 13.41 mm, which was more than 5 times of that of CK. After 3 weeks, the Xac cultured with the leaves of ‘Bingtang’ sweet orange in MT medium grew smoothly and steadily. Compared with that of CK, the diameter of Xac cultured with the ‘Bingtang’ sweet orange was very significantly different. The Xac cultured with the leaves of ‘Bingtang’ sweet orange in MA medium was 4.58 mm after 1 day, and that of CK was 6.19 mm. After 3 days of inoculation, the average diameter of Xac cultured with ‘Bingtang’ sweet orange was the same as CK, and there were no significant differences with each other. After 5 days, the Xac cultured with

  3. ВЗБИТЫЙ ДЕСЕРТ НА ОСНОВЕ МОЛОЧНОЙ СЫВОРОТКИ С ПИЩЕВЫМИ ВОЛОКНАМИ CITRI-FI

    OpenAIRE

    Плеханова, Екатерина; Банникова, Анна; Шестопалова, Наталья; Птичкина, Наталия

    2014-01-01

    Разработаны новые технологические решения по созданию взбитого десерта мусса клюквенного на основе молочной сыворотки. Технологический подход в новых разработках включал замену желатина, используемого для стабилизации пенной системы, на пищевые волокна Citri-Fi, а с целью снижения калорийности десерта была произведена замена сахара на фруктозу. Показано, что использование пищевых волокон и фруктозы во взбитых десертах позволят получить продукт с улучшенными свойствами пены, обогащенным компле...

  4. Scientific Opinion on the risk to plant health of Xanthomonas citri pv. citri and Xanthomonas citri pv. aurantifolii for the EU territory

    OpenAIRE

    EFSA Panel on Plant Health (PLH)

    2014-01-01

    The Panel conducted a pest risk assessment for Xanthomonas campestris (all strains pathogenic to Citrus) for the EU territory and an assessment of the effectiveness of present EU requirements against Xanthomonas strains pathogenic to citrus. The risk assessment was conducted under the scenario of absence of the current specific EU plant health legislation and the assumption that citrus-exporting countries apply measures to reduce yield and quality losses. Risk reduction options were systemati...

  5. Temporal variation in sex allocation in the mealybug Planococcus citri : Adaptation, constraint, or both?

    NARCIS (Netherlands)

    Ross, Laura; Langenhof, Minke B. W.; Pen, Ido; Shuker, David M.

    2012-01-01

    Sex ratio theory has been very successful in predicting under which circumstances parents should bias their investment towards a particular offspring sex. However, most examples of adaptive sex ratio bias come from species with well-defined mating systems and sex determining mechanisms, while in man

  6. Molecular evidence of polyandry in the citrus mealybug, Planococcus citri (Hemiptera: Pseudococcidae).

    Science.gov (United States)

    Seabra, Sofia G; Brás, Patricia G; Zina, Vera; Borges da Silva, Elsa; Rebelo, Maria Teresa; Figueiredo, Elisabete; Mendel, Zvi; Paulo, Octávio S; Franco, José Carlos

    2013-01-01

    The occurrence of polyandry in Planococcuscitri, presumed by earlier observations of mating behavior, was confirmed using microsatellite genotyping of pools of over 400 eggs resulting from controlled crosses of one female with two males. The genetic contribution of both mated males was confirmed in 13 out of 43 crosses. In three crosses it was possible to determine that only the first male fertilized the eggs, which may be due to sperm competition or unviable sperm supply. The microsatellite analysis also allowed the confirmation of aspects of the chromosomal inheritance detected previously in cytogenetic studies in Planococcuscitri, namely that only one of the alleles is transmitted by the male, indicating that the males are functionally haploid, supporting the observation of Paternal Genome Elimination (PGE) in these insects.

  7. Type II Toxin-antitoxin distribution and adaptive aspects on Xanthomonas genomes: focus on Xanthomonas citri

    Directory of Open Access Journals (Sweden)

    Paula Maria Moreira Martins

    2016-05-01

    Full Text Available Prokaryotic toxin-antitoxin (TA systems were first described as being designed to prevent plasmid loss in bacteria. However, with the increase in prokaryotic genome sequencing, recently many TAs have been found in bacterial chromosomes, having other biological functions, such as environmental stress response. To date, only few studies have focused on TA systems in phytopathogens, and their possible impact on the bacterial fitness. This may be especially important for pathogens like Xanthomonas spp., which live epiphytically before entering the host. In this study, we looked for TA systems in the genomes of ten Xanthomonas strains. We verified that citrus-infecting pathovars have, on average, 50% more TAs than other Xanthomonas spp. and no genome harbors classical toxins such as MqsR, RelB and HicA. Only one TA system (PIN_VapC-FitB-like/SpoVT_AbrB was conserved among the Xanthomonas genomes, suggesting adaptive aspects concerning its broad occurrence. We also detected a trend of toxin gene loss in this genus, while the antitoxin gene was preferably maintained. This study discovers the quantitative and qualitative differences among the type II TA systems present in Xanthomonas spp., especially concerning the citrus-infecting strains. In addition, the antitoxin retention in the genomes is possibly related with the resistance mechanism of further TA infections as an anti-addiction system or might also be involved in regulation of certain specific genes.

  8. Whole genome sequence of “Candidatus Profftella armatura” from Diaphorina citri in Guangdong, China

    Science.gov (United States)

    The genome of “Candidatus Profftella armatura” strain YCPA, a symbiont of Asian citrus psyllid, from Guangdong, China, was sequenced. The strain chromosome was 457,565 bp with 24.3% G+C content, 364 predicted open reading frames (ORFs), and 38 RNA genes. The strain also contains a 5,458 bp plasmid, ...

  9. Occurrence and molecular detection of Spiroplasma citri in carrots and Circulifer tenellus in Mexico

    Science.gov (United States)

    In the fall of 2014, carrot plants in Zacatecas, Mexico, were found with yellow, brown (chlorotic), and/or purple-colored leaves, small and/or rolled leaves, and hairy, deformed, and/or small roots. Molecular diagnostics of these symptomatic plants failed to detect phytoplasmas in these samples, bu...

  10. Molecular evidence of polyandry in the citrus mealybug, Planococcus citri (Hemiptera: Pseudococcidae.

    Directory of Open Access Journals (Sweden)

    Sofia G Seabra

    Full Text Available The occurrence of polyandry in Planococcuscitri, presumed by earlier observations of mating behavior, was confirmed using microsatellite genotyping of pools of over 400 eggs resulting from controlled crosses of one female with two males. The genetic contribution of both mated males was confirmed in 13 out of 43 crosses. In three crosses it was possible to determine that only the first male fertilized the eggs, which may be due to sperm competition or unviable sperm supply. The microsatellite analysis also allowed the confirmation of aspects of the chromosomal inheritance detected previously in cytogenetic studies in Planococcuscitri, namely that only one of the alleles is transmitted by the male, indicating that the males are functionally haploid, supporting the observation of Paternal Genome Elimination (PGE in these insects.

  11. Parallel evolution of cytochrome b mediated bifenazate resistance in the citrus red mite Panonychus citri

    NARCIS (Netherlands)

    T. Van Leeuwen; P. Van Nieuwenhuyse; B. Vanholme; W. Dermauw; R. Nauen; L. Tirry

    2011-01-01

    Bifenazate is a recently developed acaricide that is mainly used to control spider mites on a variety of crops. Although first thought to be a neurotoxin, genetic evidence obtained from bifenazate resistant Tetranychus urticae strains suggested an alternative mode of action as a Qo pocket inhibitor

  12. Differential effects of exposure to ambient vanilla and citris aromas on mood, arousal and food choice

    NARCIS (Netherlands)

    Wijk, de R.A.; Zijlstra, S.

    2012-01-01

    Background Aromas have been associated with physiological, psychological affective and behavioral effects. We tested whether effects of low-level exposure to two ambient food-related aromas (citrus and vanilla) could be measured with small numbers of subjects, low-cost physiological sensors and semi

  13. Type II Toxin-Antitoxin Distribution and Adaptive Aspects on Xanthomonas Genomes: Focus on Xanthomonas citri.

    Science.gov (United States)

    Martins, Paula M M; Machado, Marcos A; Silva, Nicholas V; Takita, Marco A; de Souza, Alessandra A

    2016-01-01

    Prokaryotic toxin-antitoxin (TA) systems were first described as being designed to prevent plasmid loss in bacteria. However, with the increase in prokaryotic genome sequencing, recently many TAs have been found in bacterial chromosomes, having other biological functions, such as environmental stress response. To date, only few studies have focused on TA systems in phytopathogens, and their possible impact on the bacterial fitness. This may be especially important for pathogens like Xanthomonas spp., which live epiphytically before entering the host. In this study, we looked for TA systems in the genomes of 10 Xanthomonas strains. We verified that citrus-infecting pathovars have, on average, 50% more TAs than other Xanthomonas spp. and no genome harbors classical toxins such as MqsR, RelB, and HicA. Only one TA system (PIN_VapC-FitB-like/SpoVT_AbrB) was conserved among the Xanthomonas genomes, suggesting adaptive aspects concerning its broad occurrence. We also detected a trend of toxin gene loss in this genus, while the antitoxin gene was preferably maintained. This study discovers the quantitative and qualitative differences among the type II TA systems present in Xanthomonas spp., especially concerning the citrus-infecting strains. In addition, the antitoxin retention in the genomes is possibly related with the resistance mechanism of further TA infections as an anti-addiction system or might also be involved in regulation of certain specific genes. PMID:27242687

  14. 76 FR 23449 - Citrus Canker, Citrus Greening, and Asian Citrus Psyllid; Interstate Movement of Regulated...

    Science.gov (United States)

    2011-04-27

    ... to movement. Citrus canker is a plant disease that is caused by the bacterium Xanthomonas citri subsp... quarantined for citrus canker are found in Sec. 301.75-6. Citrus greening, also known as Huanglongbing disease of citrus, is considered to be one of the most serious citrus diseases in the world. Citrus...

  15. 75 FR 62455 - Importation of Fresh Unshu Oranges From the Republic of Korea Into the Continental United States

    Science.gov (United States)

    2010-10-12

    .... These regulations are intended to prevent the introduction of citrus canker, among other citrus diseases... canker is a disease that affects citrus and is caused by the infectious bacterium Xanthomonas citri subsp... Japan certifying that the fruit is apparently free of citrus canker disease. (7) The Unshu oranges...

  16. The effect of nutritional spray programs applied to mitigate symptoms of Huanglongbing on fruit drop caused by HLB and citrus canker on ‘Hamlin’ orange trees

    OpenAIRE

    Roberts, P. D.; Rouse, R. E.; Teems, S. S.; Sytsma, R. E.; Shobert, Z.

    2014-01-01

    Huanglongbing (HLB) was detected in Florida in 2005 and has reached 100% incidence in certain citrus plantings in southwest Florida. The putative causal agent of HLB in Florida is the bacterium Candidatus Liberibacter asiaticus (CLa).  Citrus canker caused by the bacterium Xanthomonas citri subsp. citri is endemic in Florida.  In 2011 and 2012, fruit drop on young ‘Hamlin’ trees with symptoms of HLB and/or citrus canker was particularly severe, with more than 90% fruit drop recorded. Nutritio...

  17. Generating Asian citrus Psyllid Diaphorina citri Kuwayama (Homoptera: Psyllidae) with twisting wings to prevent the spread of citrus greening disease

    OpenAIRE

    El-Shesheny, I.; Harjeri, S.; Gowda, S.; Killiny, N.

    2014-01-01

    Huanglongbing (HLB) is seriously threatening and causing considerable economic losses to the citrus groves. Its Management depends critically on the control of the Asian citrus Psyllid (ACP), the vector of the cause of HLB, Candidatus Liberibacter asiaticus bacteria (CLas). Silencing genes by RNA interference (RNAi) is a promising technique to control pests. In this study, the abnormal disk wing (awd) has been selected from the available psyllid annotated genome. It has been known that awd ge...

  18. Corn Citri Infection Early Warning and Climate%玉米红蜘蛛发生预警与气候

    Institute of Scientific and Technical Information of China (English)

    张洁

    2009-01-01

    近年来,玉米红蜘蛛的发生为害日趋严重,成为影响玉米生产的主要因素之一.害虫种群数量消长与气候因子密切相关,而害虫发生的高峰期、数量等生物参数的获取是害虫测报工作的重要组成部分,是决定害虫测报精确性的首要因素.21世纪是生命科学与信息科学时代,应用计算机信息技术为农业害虫的系统分析与检测预警及防治决策提供科学、便捷的先进手段,使得对农业复杂系统中的大量信息进行多功能综合分析处理成为可能.%The com red spider's harm is serious day by day and becomes one of primary factors influencing corn production. The harmful insect population fluctuation and the climatic factors are closely related, but to get the harmful insect occurs biological parameters, peak stage, quantity are important components to harmful insect measuring and reporting work and decides definition of the harmful insect measuring and reporting. The 21st century is the age of life sciences and the information science. The application of computer information technology in insect pest analysis/examination/early warning and management decision-making makes it possible for multi-purposed generalized analysis with massive information planted in agricultural complicated system.

  19. Asian citrus psyllids and shade: Survival of Diaphorina citri on Murraya exotica foliage exposed to different levels of light

    Science.gov (United States)

    Using shade cloths of different densities, potted individuals of Murraya exotica (Rutaceae) were exposed to levels of photosynthetic radiation (PAR) varying from 48 µmol photons per meter2 per second to 1562 µmol photons per meter2 per second (average of three readings taken at noon during condition...

  20. Silencing abnormal wing disc gene of the Asian citrus psyllid, Diaphorina citri disrupts adult wing development and increases nymph mortality.

    Science.gov (United States)

    El-Shesheny, Ibrahim; Hajeri, Subhas; El-Hawary, Ibrahim; Gowda, Siddarame; Killiny, Nabil

    2013-01-01

    Huanglongbing (HLB) causes considerable economic losses to citrus industries worldwide. Its management depends on controlling of the Asian citrus Psyllid (ACP), the vector of the bacterium, Candidatus Liberibacter asiaticus (CLas), the causal agent of HLB. Silencing genes by RNA interference (RNAi) is a promising tool to explore gene functions as well as control pests. In the current study, abnormal wing disc (awd) gene associated with wing development in insects is used to interfere with the flight of psyllids. Our study showed that transcription of awd is development-dependent and the highest level was found in the last instar (5(th)) of the nymphal stage. Micro-application (topical application) of dsRNA to 5(th) instar of nymphs caused significant nymphal mortality and adult wing-malformation. These adverse effects in ACP were positively correlated with the amounts of dsRNA used. A qRT-PCR analysis confirmed the dsRNA-mediated transcriptional down-regulation of the awd gene. Significant down-regulation was required to induce a wing-malformed phenotype. No effect was found when dsRNA-gfp was used, indicating the specific effect of dsRNA-awd. Our findings suggest a role for awd in ACP wing development and metamorphosis. awd could serve as a potential target for insect management either via direct application of dsRNA or by producing transgenic plants expressing dsRNA-awd. These strategies will help to mitigate HLB by controlling ACP.

  1. Silencing abnormal wing disc gene of the Asian citrus psyllid, Diaphorina citri disrupts adult wing development and increases nymph mortality.

    Directory of Open Access Journals (Sweden)

    Ibrahim El-Shesheny

    Full Text Available Huanglongbing (HLB causes considerable economic losses to citrus industries worldwide. Its management depends on controlling of the Asian citrus Psyllid (ACP, the vector of the bacterium, Candidatus Liberibacter asiaticus (CLas, the causal agent of HLB. Silencing genes by RNA interference (RNAi is a promising tool to explore gene functions as well as control pests. In the current study, abnormal wing disc (awd gene associated with wing development in insects is used to interfere with the flight of psyllids. Our study showed that transcription of awd is development-dependent and the highest level was found in the last instar (5(th of the nymphal stage. Micro-application (topical application of dsRNA to 5(th instar of nymphs caused significant nymphal mortality and adult wing-malformation. These adverse effects in ACP were positively correlated with the amounts of dsRNA used. A qRT-PCR analysis confirmed the dsRNA-mediated transcriptional down-regulation of the awd gene. Significant down-regulation was required to induce a wing-malformed phenotype. No effect was found when dsRNA-gfp was used, indicating the specific effect of dsRNA-awd. Our findings suggest a role for awd in ACP wing development and metamorphosis. awd could serve as a potential target for insect management either via direct application of dsRNA or by producing transgenic plants expressing dsRNA-awd. These strategies will help to mitigate HLB by controlling ACP.

  2. Analysis of Transcriptome Differences between Resistant and Susceptible Strains of the Citrus Red Mite Panonychus citri (Acari: Tetranychidae)

    OpenAIRE

    Bin Liu; Gaofei Jiang; Yunfei Zhang; Junli Li; Xiaojiao Li; Jiansu Yue; Fei Chen; Haoqiang Liu; Hongjun Li; Shiping Zhu; Jinjun Wang; Chun Ran

    2011-01-01

    BACKGROUND: The citrus red mite is a worldwide citrus pest and a common sensitizing allergen of asthma and rhinitis. It has developed strong resistance to many registered acaricides, However, the molecular mechanisms of resistance remain unknown. we therefore used next generation sequencing technology to investigate the global transcriptomes between resistant strains and susceptible strains. RESULTS: We obtained 34,159, 30,466 and 32,217 unigenes by assembling the SS reads, RS reads and SS&RS...

  3. Real-time PCR for Detection and Differentiation of Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus

    OpenAIRE

    2007-01-01

    Real-time PCR for Detection and Differentiation of Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus SWEDEN (B?verud, V.) SWEDEN Received: 2006-10-03 Revised: 2007-03-27 Accepted: 2007-04-05

  4. Characterization of the parasporal inclusion of Bacillus thuringiensis subsp. kyushuensis.

    OpenAIRE

    Held, G. A.; Kawanishi, C. Y.; Huang, Y. S.

    1990-01-01

    Electron microscopy of Bacillus thuringiensis subsp. kyushuensis revealed that the parasporal inclusions are composed of a homogeneous center surrounded by a thick, electron-dense coating. Antibodies directed against the 135- and 65-kilodalton B. thuringiensis subsp. israelensis peptides cross-reacted with the 70- and 26-kilodalton peptides, respectively, of B. thuringiensis subsp. kyushuensis.

  5. Structural relatedness between mosquitocidal endotoxins of Bacillus thuringiensis subsp. israelensis.

    OpenAIRE

    Garduno, F; Thorne, L.; Walfield, A M; Pollock, T J

    1988-01-01

    A mosquitocidal toxin gene, cloned from Bacillus thuringiensis subsp. israelensis, was introduced into mutant crystal-negative B. thuringiensis subsp. israelensis cells. Partial toxicity to mosquitos was restored. The 58-kilodalton cloned gene product is a minor protein component of B. thuringiensis subsp. israelensis crystals and is structurally related to a major, 135-kilodalton crystal toxin.

  6. Laryngeal Scleroma Associated with Klebsiella pneumoniae subsp. ozaenae

    OpenAIRE

    De Champs, C; Vellin, J. F.; Diancourt, L.; Brisse, S.; Kemeny, J L; Gilain, L.; Mom, T.

    2005-01-01

    Klebsiella pneumoniae subsp. ozaenae was isolated from the pharynx of a woman with laryngeal scleroma. K. pneumoniae subsp. ozaenae is rarely isolated from clinical infections and has never been reported in laryngeal scleroma, which is usually caused by K. pneumoniae subsp. rhinoscleromatis.

  7. Complete Genome Sequences of Campylobacter hyointestinalis subsp. hyointestinalis Strain LMG 9260 and C. hyointestinalis subsp. lawsonii Strain LMG 15993.

    Science.gov (United States)

    Miller, William G; Yee, Emma; Chapman, Mary H

    2016-01-01

    Campylobacter hyointestinalis is isolated primarily from ruminants and swine, but is also occasionally isolated from humans. C. hyointestinalis is currently divided into two subspecies, C. hyointestinalis subsp. hyointestinalis and C. hyointestinalis subsp. lawsonii This study describes the first closed whole-genome sequences of C. hyointestinalis subsp. hyointestinalis isolate LMG 9260 and C. hyointestinalis subsp. lawsonii isolate LMG 15993. PMID:27417840

  8. Campylobacter fetus subsp. fetus in homosexual males.

    OpenAIRE

    Devlin, H R; McIntyre, L

    1983-01-01

    Campylobacter fetus subsp. fetus was isolated from the stools of two homosexual males. One was asymptomatic at the time of isolation. The other presented with diarrhea. Both isolates were initially grown at 42 degrees C. This organism should be included among the list of organisms that are found in homosexual males.

  9. Iridoid Glucosides from Lamium garganicum subsp. laevigatum

    DEFF Research Database (Denmark)

    Tayfun, Ersöz; Kaya, Duygu; Yalcin, Funda Nuray;

    2007-01-01

    Phytochemical investigations on the above ground parts of Lamium garganicum subsp. laevigatum resulted in the isolation of seven iridoid glucosides, shanzhiside methyl ester (1), barlerin (8-O-acetylshanzhiside methyl ester; 2), 6-O-syringyl-8-O-acetylshanzhiside methyl ester (3), 6β-hydroxyipola...

  10. Odontites verna (Bell.) Dum. subsp. pumila (Nordst.) A. Pedersen in Nederland

    NARCIS (Netherlands)

    Pedersen, Anfred

    1963-01-01