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Sample records for citrus canker xanthomonas

  1. 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...

  2. Selection of Small Synthetic Antimicrobial Peptides Inhibiting Xanthomonas citri subsp. citri Causing Citrus Canker

    Science.gov (United States)

    Choi, Jeahyuk; Park, Euiho; Lee, Se-Weon; Hyun, Jae-Wook; Baek, Kwang-Hyun

    2017-01-01

    Citrus canker disease decreases the fruit quality and yield significantly, furthermore, emerging of streptomycin-resistant pathogens threatens the citrus industry seriously because of a lack of proper control agents. Small synthetic antimicrobial peptides (AMPs) could be a promising alternative. Fourteen hexapeptides were selected by using positional scanning of synthetic peptide combinatorial libraries. Each hexapeptide showed different antimicrobial spectrum against Bacillus, Pseudomonas, Xanthomonas, and Candida species. Intriguingly, BHC10 showed bactericidal activity exclusively on Xanthomonas citri subsp. citri (Xcc), while BHC7 was none-active exclusively against two Pseudomonas spp. at concentration of 100 μg/ml suggesting potential selectivity constrained in hexapeptide frame. Three hexapeptides, BHC02, 06 and 11, showed bactericidal activities against various Xcc strains at concentration of 10 μg/ml. When they were co-infiltrated with pathogens into citrus leaves the disease progress was suppressed significantly. Further study would be needed to confirm the actual disease control capacity of the selected hexapeptides. PMID:28167892

  3. Positive selection is the main driving force for evolution of citrus canker-causing Xanthomonas.

    Science.gov (United States)

    Zhang, Yunzeng; Jalan, Neha; Zhou, Xiaofeng; Goss, Erica; Jones, Jeffrey B; Setubal, João C; Deng, Xiaoling; Wang, Nian

    2015-10-01

    Understanding the evolutionary history and potential of bacterial pathogens is critical to prevent the emergence of new infectious bacterial diseases. Xanthomonas axonopodis subsp. citri (Xac) (synonym X. citri subsp. citri), which causes citrus canker, is one of the hardest-fought plant bacterial pathogens in US history. Here, we sequenced 21 Xac strains (14 XacA, 3 XacA* and 4 XacA(w)) with different host ranges from North America and Asia and conducted comparative genomic and evolutionary analyses. Our analyses suggest that acquisition of beneficial genes and loss of detrimental genes most likely allowed XacA to infect a broader range of hosts as compared with XacA(w) and XacA*. Recombination was found to have occurred frequently on the relative ancient branches, but rarely on the young branches of the clonal genealogy. The ratio of recombination/mutation ρ/θ was 0.0790±0.0005, implying that the Xac population was clonal in structure. Positive selection has affected 14% (395 out of 2822) of core genes of the citrus canker-causing Xanthomonas. The genes affected are enriched in 'carbohydrate transport and metabolism' and 'DNA replication, recombination and repair' genes (Pcitrus canker-causing Xanthomonas. Our results suggest that both metabolism and virulence genes provide advantages to endow XacA with higher virulence and a wider host range. Our analysis advances our understanding of the genomic basis of specialization by positive selection in bacterial evolution.

  4. 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.

  5. 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.

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

    Science.gov (United States)

    Moreira, Leandro M; Almeida, Nalvo F; Potnis, Neha; Digiampietri, Luciano A; Adi, Said S; Bortolossi, Julio C; da Silva, Ana C; da Silva, Aline M; de Moraes, Fabrício E; de Oliveira, Julio C; de Souza, Robson F; Facincani, Agda P; Ferraz, André L; Ferro, Maria I; Furlan, Luiz R; Gimenez, Daniele F; Jones, Jeffrey B; Kitajima, Elliot W; Laia, Marcelo L; Leite, Rui P; Nishiyama, Milton Y; Rodrigues Neto, Julio; Nociti, Letícia A; Norman, David J; Ostroski, Eric H; Pereira, Haroldo A; Staskawicz, Brian J; Tezza, Renata I; Ferro, Jesus A; Vinatzer, Boris A; Setubal, João C

    2010-04-13

    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. 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. 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.

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

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    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.

  8. 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.

  9. Complete Genome Sequences of Six Copper-Resistant Xanthomonas citri pv.?citri Strains Causing Asiatic Citrus Canker, Obtained Using Long-Read Technology

    OpenAIRE

    Richard, Damien; Boyer, Claudine; Vernière, Christian; Canteros, B.I.; Lefeuvre, Pierre; Pruvost, Olivier

    2017-01-01

    The gammaproteobacterium Xanthomonas citri pv. citri causes Asiatic citrus canker. Pathotype A strains have a broad host range, which includes most commercial citrus species, and they cause important economic losses worldwide. Control often relies on frequent copper sprays. We present here the complete genomes of six X. citri pv. citri copper-resistant strains. (Résumé d'auteur)

  10. Complete Genome Sequences of Six Copper-Resistant Xanthomonas citri pv. citri Strains Causing Asiatic Citrus Canker, Obtained Using Long-Read Technology

    Science.gov (United States)

    Richard, Damien; Boyer, Claudine; Vernière, Christian; Canteros, Blanca I.; Lefeuvre, Pierre

    2017-01-01

    ABSTRACT The gammaproteobacterium Xanthomonas citri pv. citri causes Asiatic citrus canker. Pathotype A strains have a broad host range, which includes most commercial citrus species, and they cause important economic losses worldwide. Control often relies on frequent copper sprays. We present here the complete genomes of six X. citri pv. citri copper-resistant strains. PMID:28336584

  11. 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.

  12. 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.

  13. Comparative ultrastructure of nonwounded Mexican lime and Yuzu leaves infected with the citrus canker bacterium Xanthomonas citri pv. citri.

    Science.gov (United States)

    Lee, In Jung; Kim, Ki Woo; Hyun, Jae Wook; Lee, Yong Hoon; Park, Eun Woo

    2009-07-01

    Ultrastructural aspects of citrus canker development were investigated in nonwounded leaves of citrus species by transmission electron microscopy (TEM). A susceptible species Mexican lime and a resistant species Yuzu were spray-inoculated with a virulent strain of Xanthomonas citri pv. citri. Initial symptoms occurred on Mexican lime approximately 9 days after inoculation, whereas they appeared on Yuzu mostly 11 days after inoculation. In Mexican lime leaves, the bacterial invasion was usually accompanied by host cell wall dissolution and cellular disruption. Fibrillar materials from degenerated cell walls were usually found in intercellular spaces. Damaged host cells with necrotic cytoplasm showed the localized separation of plasma membrane from the cell wall. Bacterial multiplication and electron-transparent capsule-like structures around bacteria were commonly observed. Meanwhile, cell wall protuberances were prominent outside host cell walls in response to bacterial invasion in Yuzu leaves. Occlusion of intercellular spaces was also formed by the fusion of two or more individual cell wall protuberances originated from two adjacent host cells. Papillae-like materials accumulated locally within host cells in close proximity to bacteria. Some bacteria were found to be undergoing degeneration in xylem vessels. Also, the shrunken, inactive bacteria were surrounded by electron-translucent fibrillar materials in intercellular spaces, implying bacterial immobilization. These cellular responses are thought to be the consequences of defense responses of Yuzu leaves to invading bacteria. In both citrus species, X. citri pv. citri contained polyphosphate bodies showing electron-dense and elliptical structures in cytoplasm.

  14. The filamentous phage XacF1 causes loss of virulence in Xanthomonas axonopodis pv. citri, the causative agent of citrus canker disease

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    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.

  15. 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. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  16. 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.

  17. Overexpression of a modified plant thionin enhances disease resistance to citrus canker and huanglongbing (HLB, citrus greening)

    Science.gov (United States)

    Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the United States citrus industry. Citrus canker is also an economically important disease associated with a bacterial pathogen (Xanthomonas citri). In this study, we characterized e...

  18. 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.

  19. Citrus diseases with global ramifications including citrus canker and huanglongbing

    Science.gov (United States)

    Although there are a number of diseases that plague citrus production worldwide, two bacterial diseases are particularly problematic. Both are of Asian origin and currently cause severe economic damage: Asiatic citrus canker (ACC) and citrus huanglongbing (HLB). Although ACC has been found in the ...

  20. Overexpression of a Modified Plant Thionin Enhances Disease Resistance to Citrus Canker and Huanglongbing (HLB).

    Science.gov (United States)

    Hao, Guixia; Stover, Ed; Gupta, Goutam

    2016-01-01

    Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the US citrus industry. There are no proven strategies to eliminate HLB disease and no cultivar has been identified with strong HLB resistance. Citrus canker is also an economically important disease associated with a bacterial pathogen (Xanthomonas citri). In this study, we characterized endogenous citrus thionins and investigated their expression in different citrus tissues. Since no HLB-resistant citrus cultivars have been identified, we attempted to develop citrus resistant to both HLB and citrus canker through overexpression of a modified plant thionin. To improve effectiveness for disease resistance, we modified and synthesized the sequence encoding a plant thionin and cloned into the binary vector pBinPlus/ARS. The construct was then introduced into Agrobacterium strain EHA105 for citrus transformation. Transgenic Carrizo plants expressing the modified plant thionin were generated by Agrobacterium-mediated transformation. Successful transformation and transgene gene expression was confirmed by molecular analysis. Transgenic Carrizo plants expressing the modified thionin gene were challenged with X. citri 3213 at a range of concentrations, and a significant reduction in canker symptoms and a decrease in bacterial growth were demonstrated compared to nontransgenic plants. Furthermore, the transgenic citrus plants were challenged with HLB via graft inoculation. Our results showed significant Las titer reduction in roots of transgenic Carrizo compared with control plants and reduced scion Las titer 12 months after graft inoculation. These data provide promise for engineering citrus disease resistance against HLB and canker.

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

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    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.

  2. Overexpression of a modified plant thionin enhances disease resistance to citrus canker and Huanglongbing (HLB

    Directory of Open Access Journals (Sweden)

    Guixia Hao

    2016-07-01

    Full Text Available Huanglongbing (HLB or citrus greening disease caused by Candidatus Liberibacter asiaticus (Las is a great threat to the US citrus industry. There are no proven strategies to eliminate HLB disease and no cultivar has been identified with strong HLB resistance. Citrus canker is also an economically important disease associated with a bacterial pathogen (Xanthomonas citri. In this study, we characterized endogenous citrus thionins and investigated their expression in different citrus tissues. Since no HLB-resistant citrus cultivars have been identified, we attempted to develop citrus resistant to both HLB and citrus canker through overexpression of a modified plant thionin. To improve effectiveness for disease resistance, we modified and synthesized the sequence encoding a plant thionin and cloned into the binary vector pBinPlus/ARS. The construct was then introduced into Agrobacterium strain EHA105 for citrus transformation. Transgenic Carrizo plants expressing the modified plant thionin were generated by Agrobacterium-mediated transformation. Successful transformation and transgene gene expression was confirmed by molecular analysis. Transgenic Carrizo plants expressing the modified thionin gene were challenged with X. citri 3213 at a range of concentrations, and a significant reduction in canker symptoms and a decrease in bacterial growth were demonstrated compared to nontransgenic plants. Furthermore the transgenic citrus plants were challenged with HLB via graft inoculation. Our results showed significant Las titer reduction in roots of transgenic Carrizo compared with control plants and reduced scion Las titer twelve months after graft inoculation. These data provide promise for engineering citrus disease resistance against HLB and canker.

  3. 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.

  4. Genome editing of the disease susceptibility gene CsLOB1 in citrus confers resistance to citrus canker.

    Science.gov (United States)

    Jia, Hongge; Zhang, Yunzeng; Orbović, Vladimir; Xu, Jin; White, Frank F; Jones, Jeffrey B; Wang, Nian

    2017-07-01

    Citrus is a highly valued tree crop worldwide, while, at the same time, citrus production faces many biotic challenges, including bacterial canker and Huanglongbing (HLB). Breeding for disease-resistant varieties is the most efficient and sustainable approach to control plant diseases. Traditional breeding of citrus varieties is challenging due to multiple limitations, including polyploidy, polyembryony, extended juvenility and long crossing cycles. Targeted genome editing technology has the potential to shorten varietal development for some traits, including disease resistance. Here, we used CRISPR/Cas9/sgRNA technology to modify the canker susceptibility gene CsLOB1 in Duncan grapefruit. Six independent lines, DLOB 2, DLOB 3, DLOB 9, DLOB 10, DLOB 11 and DLOB 12, were generated. Targeted next-generation sequencing of the six lines showed the mutation rate was 31.58%, 23.80%, 89.36%, 88.79%, 46.91% and 51.12% for DLOB 2, DLOB 3, DLOB 9, DLOB 10, DLOB 11 and DLOB 12, respectively, of the cells in each line. DLOB 2 and DLOB 3 showed canker symptoms similar to wild-type grapefruit, when inoculated with the pathogen Xanthomonas citri subsp. citri (Xcc). No canker symptoms were observed on DLOB 9, DLOB 10, DLOB 11 and DLOB 12 at 4 days postinoculation (DPI) with Xcc. Pustules caused by Xcc were observed on DLOB 9, DLOB 10, DLOB 11 and DLOB 12 in later stages, which were much reduced compared to that on wild-type grapefruit. The pustules on DLOB 9 and DLOB 10 did not develop into typical canker symptoms. No side effects and off-target mutations were detected in the mutated plants. This study indicates that genome editing using CRISPR technology will provide a promising pathway to generate disease-resistant citrus varieties. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  5. 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

    a wide range of microorganisms pathogenic to man, animals, and plants. An important problem to solve with antimicrobial treatments is the development of resistance in these microorganisms, including phytopathogenic bacteria, to the currently used active ingredients. In this study, antagonism tests with cells (cross-streaking and cell-free culture supernatants (CCS (agar diffusion test from Zm cultures, isolated from sugarcane juice in Tucumán, were carried out, measuring activity against Xanthomonas citri subsp. citri (Xcc, the causal agent of citrus canker. Xcc isolates sensitive (Xc and resistant (Xcr to copper pesticides were included in these tests. Results showed that indicator bacteria were completely inhibited by cells of Zm, which had a bactericide effect. Both Xc and Xcr were sensitive to the CCS in the agar diffusion method. Previous studies had revealed the deleterious effects of metabolites from Zm on cell membranes of E. coli AB1133, inhibiting the respiration of the bacteria inmediately after CCS addition. On the basis of these results, the effects of CCS on Xcc respiration were studied, verifyng a similar response. This would indicate that the site of action of these antimicrobial compounds is also located at the cell membrane of the bacteria under study. Based on these results, additional studies are suggested to evaluate Zm-derived products on the control of diseases that affect economically important crops, such as citrus canker.

  6. 78 FR 58992 - Notice of Request for Extension of Approval of an Information Collection; Citrus Canker...

    Science.gov (United States)

    2013-09-25

    ... States. Citrus canker is a plant disease that affects plant and plant parts, including fresh fruit of... Collection; Citrus Canker; Interstate Movement of Regulated Nursery Stock and Fruit From Quarantined Areas... nursery stock and fruit from quarantined areas to prevent the spread of citrus canker. DATES: We...

  7. 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...

  8. Expressão gênica diferencial de laranja Pêra Rio (Citrus sinensis (L.) Osbeck) e Lima Ácida 'Galego' (Citrus aurantifolia Swingle) em resposta à infecção por Xanthomonas citri subsp. citri

    OpenAIRE

    Cavallini, Juliana da Silva [UNESP

    2013-01-01

    The citrus agribusiness is very important to the Brazilian economy, but the increase of diseases in the last decade has caused great economic losses to the sector. The citrus canker, caused by the bacterium Xanthomonas citri subsp. citri (Xac), is a serious disease that attacks all citrus species economically important worldwide and there is not an effective method for its control. In this study, RNASeq was used to analyze the transcriptional profiles of two contrasting citrus genotypes regar...

  9. The Role of Image Enhancement in Citrus Canker Disease Detection

    Directory of Open Access Journals (Sweden)

    K. Padmavathi

    2016-09-01

    Full Text Available Digital image processing is employed in numerous areas of biology to identify and analyse problems. This approach aims to use image processing techniques for citrus canker disease detection through leaf inspection. Citrus canker is a severe bacterium-based citrus plant disease. The symptoms of citrus canker disease typically occur in the leaves, branches, fruits and thorns. The leaf images show the health status of the plant and facilitate the observation and detection of the disease level at an early stage. The leaf image analysis is an essential step for the detection of numerous plant diseases. The proposed approach consists of two stages to improve the clarity and quality of leaf images. The primary stage uses Recursively Separated Weighted Histogram Equalization (RSWHE, which improves the contrast level. The second stage removes the unwanted noise using a Median filter. This proposed approach uses these methods to improve the clarity of the images and implements these methods in lemon citrus canker disease detection.

  10. Production of Transgenic Anliucheng Sweet Orange (Citrus sinensis Osbeck) with Xa21 Gene for Potential Canker Resistance

    Institute of Scientific and Technical Information of China (English)

    LI Ding-li; XIAO Xuan; and GUO Wen-wu

    2014-01-01

    Citrus canker, an epidemic quarantine disease caused by Xanthomonas axonopodis pv. citri, has brought a great damage in citrus production worldwide. Herein, a rice PRR (pattern recognition receptor) gene Xa21 together with GUS reporter gene and hygromycin phosphotransferase gene (HPT) was introduced into Anliucheng sweet orange (Citrus sinensis Osbeck) via Agrobacterium-mediated transformation of embryogenic callus. The transgenic calluses were screened on MT basal medium containing hygromycin (HYG) and detected by histochemical GUS staining. The transgenic plantlets were recovered through somatic embryogenesis pathway. The regenerated plantlets were accustomed to and maintained in the greenhouse. The transgene integration of recovered plantlets was identiifed by PCR and Southern blot hybridization. It showed that all the transgenic plantlets tested had undergone single copy integration, the expression of Xa21 in eight different transgenic lines detected by qRT-PCR can be divided into three grades, high for T5 and T6, middle for T4 and low for the rest. The tolerance to citrus canker disease of the three recovered transgenic lines T2, T4 and T6 was assessed by in vitro pin-puncture inoculation. The results showed that all the three transgenic lines conferred improved resistance to citrus canker bacterium infection and the T4 transgenic line displayed the highest resistance. The mechanism and feasibility of rice Xa21 in triggering innate immunity in citrus was brielfy discussed.

  11. Transcriptional profiling of canker-resistant transgenic sweet orange (Citrus sinensis Osbeck) constitutively overexpressing a spermidine synthase gene.

    Science.gov (United States)

    Fu, Xing-Zheng; Liu, Ji-Hong

    2013-01-01

    Citrus canker disease caused by Xanthomonas citri subsp. citri (Xcc) is one of the most devastating diseases affecting the citrus industry worldwide. In our previous study, the canker-resistant transgenic sweet orange (Citrus sinensis Osbeck) plants were produced via constitutively overexpressing a spermidine synthase. To unravel the molecular mechanisms underlying Xcc resistance of the transgenic plants, in the present study global transcriptional profiling was compared between untransformed line (WT) and the transgenic line (TG9) by hybridizing with Affymetrix Citrus GeneChip. In total, 666 differentially expressed genes (DEGs) were identified, 448 upregulated, and 218 downregulated. The DEGs were classified into 33 categories after Gene ontology (GO) annotation, in which 68 genes are in response to stimulus and involved in immune system process, 12 genes are related to cell wall, and 13 genes belong to transcription factors. These genes and those related to starch and sucrose metabolism, glutathione metabolism, biosynthesis of phenylpropanoids, and plant hormones were hypothesized to play major roles in the canker resistance of TG9. Semiquantitative RT-PCR analysis showed that the transcript levels of several candidate genes in TG9 were significantly higher than in WT both before and after Xcc inoculation, indicating their potential association with canker disease.

  12. Transcriptional Profiling of Canker-Resistant Transgenic Sweet Orange (Citrus sinensis Osbeck Constitutively Overexpressing a Spermidine Synthase Gene

    Directory of Open Access Journals (Sweden)

    Xing-Zheng Fu

    2013-01-01

    Full Text Available Citrus canker disease caused by Xanthomonas citri subsp. citri (Xcc is one of the most devastating diseases affecting the citrus industry worldwide. In our previous study, the canker-resistant transgenic sweet orange (Citrus sinensis Osbeck plants were produced via constitutively overexpressing a spermidine synthase. To unravel the molecular mechanisms underlying Xcc resistance of the transgenic plants, in the present study global transcriptional profiling was compared between untransformed line (WT and the transgenic line (TG9 by hybridizing with Affymetrix Citrus GeneChip. In total, 666 differentially expressed genes (DEGs were identified, 448 upregulated, and 218 downregulated. The DEGs were classified into 33 categories after Gene ontology (GO annotation, in which 68 genes are in response to stimulus and involved in immune system process, 12 genes are related to cell wall, and 13 genes belong to transcription factors. These genes and those related to starch and sucrose metabolism, glutathione metabolism, biosynthesis of phenylpropanoids, and plant hormones were hypothesized to play major roles in the canker resistance of TG9. Semiquantitative RT-PCR analysis showed that the transcript levels of several candidate genes in TG9 were significantly higher than in WT both before and after Xcc inoculation, indicating their potential association with canker disease.

  13. 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.

  14. 78 FR 63369 - Citrus Canker, Citrus Greening, and Asian Citrus Psyllid; Interstate Movement of Regulated...

    Science.gov (United States)

    2013-10-24

    ... infected plants, which render the fruit unmarketable, and cause infected fruit to drop from the trees... of the fruit, and can kill trees. Once infected, there is no cure for a tree with citrus greening. In... disease that is caused by a complex of Xanthomonas spp. bacteria and that affects plants and plant...

  15. Detection of citrus canker and Huanglongbing using fluorescence imaging spectroscopy and support vector machine technique.

    Science.gov (United States)

    Wetterich, Caio Bruno; Felipe de Oliveira Neves, Ruan; Belasque, José; Marcassa, Luis Gustavo

    2016-01-10

    Citrus canker and Huanglongbing (HLB) are citrus diseases that represent a serious threat to the citrus production worldwide and may cause large economic losses. In this work, we combined fluorescence imaging spectroscopy (FIS) and a machine learning technique to discriminate between these diseases and other ordinary citrus conditions that may be present at citrus orchards, such as citrus scab and zinc deficiency. Our classification results are highly accurate when discriminating citrus canker from citrus scab (97.8%), and HLB from zinc deficiency (95%). These results show that it is possible to accurately identify citrus diseases that present similar symptoms.

  16. Identification of putative TAL effector targets of the citrus canker pathogens shows functional convergence underlying disease development and defense response.

    Science.gov (United States)

    Pereira, Andre L A; Carazzolle, Marcelo F; Abe, Valeria Y; de Oliveira, Maria L P; Domingues, Mariane N; Silva, Jaqueline C; Cernadas, Raul A; Benedetti, Celso E

    2014-02-25

    Transcriptional activator-like (TAL) effectors, formerly known as the AvrBs3/PthA protein family, are DNA-binding effectors broadly found in Xanthomonas spp. that transactivate host genes upon injection via the bacterial type three-secretion system. Biologically relevant targets of TAL effectors, i.e. host genes whose induction is vital to establish a compatible interaction, have been reported for xanthomonads that colonize rice and pepper; however, citrus genes modulated by the TAL effectors PthA"s" and PthC"s" of the citrus canker bacteria Xanthomonas citri (Xc) and Xanthomonas aurantifolii pathotype C (XaC), respectively, are poorly characterized. Of particular interest, XaC causes canker disease in its host lemon (Citrus aurantifolia), but triggers a defense response in sweet orange. Based on, 1) the TAL effector-DNA binding code, 2) gene expression data of Xc and XaC-infiltrated sweet orange leaves, and 3) citrus hypocotyls transformed with PthA2, PthA4 or PthC1, we have identified a collection of Citrus sinensis genes potentially targeted by Xc and XaC TAL effectors. Our results suggest that similar with other strains of Xanthomonas TAL effectors, PthA2 and PthA4, and PthC1 to some extent, functionally converge. In particular, towards induction of genes involved in the auxin and gibberellin synthesis and response, cell division, and defense response. We also present evidence indicating that the TAL effectors act as transcriptional repressors and that the best scoring predicted DNA targets of PthA"s" and PthC"s" in citrus promoters predominantly overlap with or localize near to TATA boxes of core promoters, supporting the idea that TAL effectors interact with the host basal transcriptional machinery to recruit the RNA pol II and start transcription. The identification of PthA"s" and PthC"s" targets, such as the LOB (lateral organ boundary) and CCNBS genes that we report here, is key for the understanding of the canker symptoms development during host

  17. Effect of amino acid application on induced resistance against citrus canker disease in lime plants

    Directory of Open Access Journals (Sweden)

    Hasabi Vahideh

    2014-07-01

    Full Text Available Citrus bacterial canker, caused by Xanthomonas citri subsp. citri (Xcc, is a destructive disease. So far, the chemicals used to control this pathogen are either ineffective or harmful to the environment. To improve control of this disease, lime (Citrus aurantifolia were treated with L-arginine, L-methionine, L-ornithine, and distilled water. Plants were inoculated with Xcc, 48 hours post treatment. Lesion diameters of inoculated leaves were evaluated four weeks after inoculation with a bacterial suspension. Changes in β-1,3-glucanase transcript levels and activity of antioxidant enzymes, catalase, peroxidase, and phenylalanine ammonia-lyase were investigated at 48 hours post treatment and 24, 48, and 72 hours post inoculation. Based on the results of phenotypic, antioxidant enzyme activity and a molecular study of the stressed plants, it was found that those plants treated with the amino acid methionine significantly increased the plant induced resistance as well as decreased the severity of disease by reducing necrotic lesion size.

  18. Lateral organ boundaries 1 is a disease susceptibility gene for citrus bacterial canker disease.

    Science.gov (United States)

    Hu, Yang; Zhang, Junli; Jia, Hongge; Sosso, Davide; Li, Ting; Frommer, Wolf B; Yang, Bing; White, Frank F; Wang, Nian; Jones, Jeffrey B

    2014-01-28

    Citrus bacterial canker (CBC) disease occurs worldwide and incurs considerable costs both from control measures and yield losses. Bacteria that cause CBC require one of six known type III transcription activator-like (TAL) effector genes for the characteristic pustule formation at the site of infection. Here, we show that Xanthomonas citri subspecies citri strain Xcc306, with the type III TAL effector gene pthA4 or with the distinct yet biologically equivalent gene pthAw from strain XccA(w), induces two host genes, CsLOB1 and CsSWEET1, in a TAL effector-dependent manner. CsLOB1 is a member of the Lateral Organ Boundaries (LOB) gene family of transcription factors, and CsSWEET1 is a homolog of the SWEET sugar transporter and rice disease susceptibility gene. Both TAL effectors drive expression of CsLOB1 and CsSWEET1 promoter reporter gene fusions when coexpressed in citrus or Nicotiana benthamiana. Artificially designed TAL effectors directed to sequences in the CsLOB1 promoter region, but not the CsSWEET1 promoter, promoted pustule formation and higher bacterial leaf populations. Three additional distinct TAL effector genes, pthA*, pthB, and pthC, also direct pustule formation and expression of CsLOB1. Unlike pthA4 and pthAw, pthB and pthC do not promote the expression of CsSWEET1. CsLOB1 expression was associated with the expression of genes associated with cell expansion. The results indicate that CBC-inciting species of Xanthomonas exploit a single host disease susceptibility gene by altering the expression of an otherwise developmentally regulated gene using any one of a diverse set of TAL effector genes in the pathogen populations.

  19. Closely-related Xanthomonas citri subsp. citri isolates trigger distinct histological and transcriptional responses in Citrus limon

    Directory of Open Access Journals (Sweden)

    Ingrid Georgina Orce

    Full Text Available ABSTRACT Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc, has an important economic impact on the citrus industry. Extensive information is available about the disease but, nevertheless, the study of plant-pathogen interactions could provide new information in the understanding of citrus canker disease. A new isolate has been identified, Xcc AT, which has a high genetic similarity (> 90 % to the virulent Xcc T strain based on genetic clustering analyses of the rep-PCR fingerprinting patterns, but it does not produce cankerous lesions in Citrus limon. In this study, we compared C. limon responses to Xcc AT and to the virulent Xcc T strain at both histological and transcriptional levels. Histologically, leaves inoculated with Xcc AT exhibited neither a typical disordering of the spongy mesophyll, nor a swelling of epidermis. A particular content (undetermined was also found in mesophyll cells near the stomata, together with increased starch accumulation. The transcriptomic profiles were compared by cDNA-AFLP technique. A total of 121 fragments derived from transcript (TDF were either specifically induced or repressed by the isolates, and 62 were sequenced. Analysis of global expression identified different classes of genes known to be involved in plant-pathogen interactions. This study constitutes the first approach of the specific interaction between the avirulent Xcc AT isolate and C. limon.

  20. 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

    ×Ichang Papeda (PI family), followed by restriction of amplified products with DdeI. The phenotype evaluation by inoculation with citrus canker [Xanthomonas axonopodis pv. Citri (Xac)] confirmed that the markerpurified and sequenced. The results confirmed that the resistance species (Kumquat and Ichang Papeda) have identical fragment sequences and DdeI restriction site, but the susceptible species lacked the DdeI site. After sequencing the BAC clone insert by primer walking, an entire gene sequence was obtained. Comparing with the previously obtained two RLK sequences 17o6RLKP and 26m19RLKP, 19hl6RLKP contained all the features of the rice Xa21 protein, including a signal peptide, the same number of leucine-rich-repeats, and transmembrane and kinase domains. Based on the ORFs of the sequence, one more specific and reliable marker was developed,which could be of great potential in future application.

  1. The Effect of Citrus Essential Oils and Their Constituents on Growth of Xanthomonas citri subsp. citri.

    Science.gov (United States)

    Mirzaei-Najafgholi, Hossein; Tarighi, Saeed; Golmohammadi, Morteza; Taheri, Parissa

    2017-04-14

    Citrus bacterial canker (CBC) caused by Xanthomonas citri subsp. citri (Xcc), is the most devastating of the citrus diseases worldwide. During our study, we found that Essential oils (EOs) of some citrus cultivars are effective on Xcc. Therefore, it prompted us to determine the plant metabolites responsible for the antibacterial properties. We obtained EOs from some locally cultivated citrus by using a Clevenger apparatus and their major constituents were identified by gas chromatography/mass spectrometry (GC-MS). The effect of Citrus aurantium, C. aurantifolia, Fortunella sp. EOs and their major constituents were evaluated against Xcc-KVXCC1 using a disk diffusion assay. Minimal inhibitory and bactericidal concentration of the EOs and their constituents were determined using the broth microdilution method. C. aurantium, C. aurantifolia Eos, and their major constituents including citral, linalool, citronellal, geraniol, α-terpineol, and linalyl acetate indicated antibacterial effects against Xcc. The C. aurantifolia EO and citral showed the highest antibacterial activity among the tested EOs and constituents with inhibition zones of 15 ± 0.33 mm and 16.67 ± 0.88 mm, respectively. Synergistic effects of the constituents were observed between α-terpineol-citral, citral-citronellal, citral-geraniol, and citronellal-geraniol by using a microdilution checkerboard assay. Transmission electron microscopy revealed that exposure of Xcc cells to citral caused cell wall damage and altered cytoplasmic density. We introduced C. aurantifolia and C. aurantium EOs, and their constituents citral, α-terpineol, citronellal, geraniol, and linalool as possible control agents for CBC.

  2. Resistance to Citrus Canker in Key/Mexican Lime Induced by β-Aminobutyric Acid and Green Tea

    Directory of Open Access Journals (Sweden)

    B. Beheshti

    2011-01-01

    Full Text Available Citrus bacterial canker, caused by Xanthomonas citri subsp. citri (Xcc, is a destructive disease. So far used chemicals to control this pathogen are either not effective or have harmful effects on the environment. To improve control of this disease, lime (Citrus aurantifolia plants inoculated with Xcc were treated with β-Aminobutyric Acid (BABA, ascorbic acid (vitamin C, thiamin (vitamin B1, green tea (Camellia sinensis, copper oxychloride and distilled water. Lesion diameters of inoculated leaves were evaluated twenty days after treatment. The results showed that BABA and green tea had inhibitory effects on disease development. None of the agents used for plant treatment had direct antimicrobial activity on Xcc, except copper oxychloride. This indicated that the inhibitory effects of BABA and green tea resulted from strengthening the defense capacities of the plant. To support this claim, partial coding sequences of Pathogenesis-Related (PR genes from lime were cloned and sequenced. Analysis of PR gene expression showed increased mRNA levels of β-1,3-glucanase and chitinase, during disease development. Reduction in lesion size and lack of antimicrobial activity indicate that BABA and green tea might be useful treatments against Xcc infection.

  3. Pathogenic Interactions Between Xanthomonas axonopodis pv. citri and Cultivars of Pummelo (Citrus grandis).

    Science.gov (United States)

    Shiotani, H; Ozaki, K; Tsuyumu, S

    2000-12-01

    ABSTRACT The aggressiveness of strains of Xanthomonas axonopodis pv. citri on seven Citrus species, including Citrus sinensis (navel orange), C. paradisi (grapefruit), C. unshiu (Satsuma mandarin), C. junos (Yuzu), C. aurantifolia ('Mexican' lime), C. tachibana (Tachibana), and C. grandis (pummelo: 'Otachibana', 'Banpeiyu', and 'Anseikan'), were assessed by comparing lesion expansion and growth in planta, using a prick inoculation method. The existence of two groups distinct in aggressiveness was demonstrated on the pummelo cultivars, whereas the remaining species tested were uniformly susceptible. The two groups of strains were distinct in lesion expansion and growth in planta; however, both caused canker lesions on the 'Otachibana' pummelo. The sensitivity of the bacterial strains to phages Cp1 and Cp2 was associated with differences in aggressiveness. Namely, all the strains sensitive to Cp2 but resistant to Cp1 were aggressive to 'Otachibana', whereas all the strains sensitive to Cp1 but resistant to Cp2 were weakly aggressive. When a repetitive sequence-based polymerase chain reaction amplification was carried out by enterobacterial repetitive intergeneric consensus (ERIC) sequences (ERIC1R and ERIC2) as the primers, these two groups were also distinguishable by the presence or absence of a 1.8-kb DNA fragment among otherwise identical fragments. The 1.8-kb fragment was amplified only from the strains aggressive to C. grandis.

  4. 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

  5. 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.

  6. Comparative genomic analysis of Xanthomonas axonopodis pv. citrumelo F1, which causes citrus bacterial spot disease, and related strains provides insights into virulence and host specificity.

    Science.gov (United States)

    Jalan, Neha; Aritua, Valente; Kumar, Dibyendu; Yu, Fahong; Jones, Jeffrey B; Graham, James H; Setubal, João C; Wang, Nian

    2011-11-01

    Xanthomonas axonopodis pv. citrumelo is a citrus pathogen causing citrus bacterial spot disease that is geographically restricted within the state of Florida. Illumina, 454 sequencing, and optical mapping were used to obtain a complete genome sequence of X. axonopodis pv. citrumelo strain F1, 4.9 Mb in size. The strain lacks plasmids, in contrast to other citrus Xanthomonas pathogens. Phylogenetic analysis revealed that this pathogen is very close to the tomato bacterial spot pathogen X. campestris pv. vesicatoria 85-10, with a completely different host range. We also compared X. axonopodis pv. citrumelo to the genome of citrus canker pathogen X. axonopodis pv. citri 306. Comparative genomic analysis showed differences in several gene clusters, like those for type III effectors, the type IV secretion system, lipopolysaccharide synthesis, and others. In addition to pthA, effectors such as xopE3, xopAI, and hrpW were absent from X. axonopodis pv. citrumelo while present in X. axonopodis pv. citri. These effectors might be responsible for survival and the low virulence of this pathogen on citrus compared to that of X. axonopodis pv. citri. We also identified unique effectors in X. axonopodis pv. citrumelo that may be related to the different host range as compared to that of X. axonopodis pv. citri. X. axonopodis pv. citrumelo also lacks various genes, such as syrE1, syrE2, and RTX toxin family genes, which were present in X. axonopodis pv. citri. These may be associated with the distinct virulences of X. axonopodis pv. citrumelo and X. axonopodis pv. citri. Comparison of the complete genome sequence of X. axonopodis pv. citrumelo to those of X. axonopodis pv. citri and X. campestris pv. vesicatoria provides valuable insights into the mechanism of bacterial virulence and host specificity.

  7. Comparative Genomic Analysis of Xanthomonas axonopodis pv. citrumelo F1, Which Causes Citrus Bacterial Spot Disease, and Related Strains Provides Insights into Virulence and Host Specificity ▿ #

    Science.gov (United States)

    Jalan, Neha; Aritua, Valente; Kumar, Dibyendu; Yu, Fahong; Jones, Jeffrey B.; Graham, James H.; Setubal, João C.; Wang, Nian

    2011-01-01

    Xanthomonas axonopodis pv. citrumelo is a citrus pathogen causing citrus bacterial spot disease that is geographically restricted within the state of Florida. Illumina, 454 sequencing, and optical mapping were used to obtain a complete genome sequence of X. axonopodis pv. citrumelo strain F1, 4.9 Mb in size. The strain lacks plasmids, in contrast to other citrus Xanthomonas pathogens. Phylogenetic analysis revealed that this pathogen is very close to the tomato bacterial spot pathogen X. campestris pv. vesicatoria 85-10, with a completely different host range. We also compared X. axonopodis pv. citrumelo to the genome of citrus canker pathogen X. axonopodis pv. citri 306. Comparative genomic analysis showed differences in several gene clusters, like those for type III effectors, the type IV secretion system, lipopolysaccharide synthesis, and others. In addition to pthA, effectors such as xopE3, xopAI, and hrpW were absent from X. axonopodis pv. citrumelo while present in X. axonopodis pv. citri. These effectors might be responsible for survival and the low virulence of this pathogen on citrus compared to that of X. axonopodis pv. citri. We also identified unique effectors in X. axonopodis pv. citrumelo that may be related to the different host range as compared to that of X. axonopodis pv. citri. X. axonopodis pv. citrumelo also lacks various genes, such as syrE1, syrE2, and RTX toxin family genes, which were present in X. axonopodis pv. citri. These may be associated with the distinct virulences of X. axonopodis pv. citrumelo and X. axonopodis pv. citri. Comparison of the complete genome sequence of X. axonopodis pv. citrumelo to those of X. axonopodis pv. citri and X. campestris pv. vesicatoria provides valuable insights into the mechanism of bacterial virulence and host specificity. PMID:21908674

  8. 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

  9. 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.

  10. Bioactive Organocopper Compound from Pseudomonas aeruginosa Inhibits the Growth of Xanthomonas citri subsp. citri

    Science.gov (United States)

    de Oliveira, Admilton G.; Spago, Flavia R.; Simionato, Ane S.; Navarro, Miguel O. P.; da Silva, Caroline S.; Barazetti, André R.; Cely, Martha V. T.; Tischer, Cesar A.; San Martin, Juca A. B.; de Jesus Andrade, Célia G. T.; Novello, Cláudio R.; Mello, João C. P.; Andrade, Galdino

    2016-01-01

    Citrus canker is a very destructive disease of citrus species. The challenge is to find new compounds that show strong antibiotic activity and low toxicity to plants and the environment. The objectives of the present study were (1) to extract, purify and evaluate the secondary metabolites with antibiotic activity produced by Pseudomonas aeruginosa LV strain in vitro against Xanthomonas citri subsp. citri (strain 306), (2) to determine the potential of semi-purified secondary metabolites in foliar application to control citrus canker under greenhouse conditions, and (3) to identify antibiotic activity in orange leaf mesophyll infected with strain 306, by electron microscopy. Two pure bioactive compounds were isolated, an organocopper antibiotic compound (OAC) and phenazine-1-carboxamide. Phenazine-1-carboxamide did not show any antibiotic activity under the experimental conditions used in this study. The OAC 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 by about 97%. The concentration used was 500 times lower than that for the recommended commercial copper-based product. Electron microscopy showed that F3d altered the exopolysaccharide matrix and caused cell lysis of the pathogen inside the citrus canker lesions. These results suggest that secondary metabolites produced by inducing P. aeruginosa LV strain have a high potential to be used as a bioproduct to control citrus canker. PMID:26903992

  11. Identification of gene candidates associated with huanglongbing tolerance using Candidatus Liberibacter asiaticus flagellin 22 as a proxy to challenge citrus

    Science.gov (United States)

    Plant defense elicited by pathogen-associated molecular patterns (PAMPs) is an important component of disease resistance. Previous research indicated the canker resistance in citrus correlates with responsiveness to Xcc-flg22, the 22 amino acid PAMP from the flagellin of Xanthomonas citri ssp. citri...

  12. Produção de frutos e incidência de cancro cítrico em laranjeiras "Monte Parnaso" enxertadas sobre sete porta-enxertos Fruit production and incidence of citrus canker lesions on "Monte Parnaso" navel orange budded on seven rootstocks

    Directory of Open Access Journals (Sweden)

    Bernadete Reis

    2008-06-01

    Full Text Available Porta-enxertos de citros podem exercer influência sobre a produção de frutos e suscetibilidade das plantas ao cancro cítrico. Este trabalho objetivou selecionar porta-enxertos que induzam elevado índice de produtividade e menor suscetibilidade das copas de laranjeiras-de-umbigo "Monte Parnaso"(Citrus sinensis à bactéria Xanthomonas axonopodis pv. citri, causadora do cancro cítrico (CC. O experimento foi desenvolvido em um pomar experimental com 10 anos de idade, plantado em espaçamento de 2,5 x 6,0m, no município de Butiá, no Estado do Rio Grande do Sul. O delineamento experimental foi em blocos ao acaso, com sete tratamentos e quatro repetições, usando duas plantas por parcela. Os tratamentos constaram dos seguintes porta-enxertos: limoeiros "Cravo" (C. limonia e "Volkameriano" (C. volkameriana., trifoliata "Flying Dragon" (Poncirus trifoliata., laranjeira "Caipira" (C. sinensis, citrangeiro "Troyer" (C. sinensis x P. trifoliata, tangerineira "Sunki" (C. sunki. e citrumeleiro "Swingle" (C. paradisi x P. trifoliata. Os parâmetros avaliados foram: incidência de CC em folhas e frutos em toda a planta e em ramos previamente selecionados, em diversas épocas. Verificou-se que as plantas enxertadas sobre citrumeleiro "Swingle" apresentaram o maior índice de produtividade e, à semelhança do "Flying Dragon", a menor incidência de CC, tanto nas folhas como nos frutos. Além disso, verificou-se também que as plantas enxertadas sobre os limoeiros "Cravo" e "Volkameriana", apesar de produzirem as mais elevadas cargas de frutos, foram as mais suscetíveis ao CC.Citrus rootstocks can exert some influences on fruit production and susceptibility of the plants to citrus canker (CC. This research was performed aiming to select rootstocks which induce higher productivity index and lower susceptibility of 'Monte Parnaso' navel orange (Citrus sinensis trees to the bacteria Xanthomonas axonopodis pv. citri. The research was carried out in an

  13. Amplified fragment length polymorphism and multilocus sequence analysis-based genotypic relatedness among pathogenic variants of Xanthomonas citri pv. citri and Xanthomonas campestris pv. bilvae.

    Science.gov (United States)

    Bui Thi Ngoc, Lan; Vernière, Christian; Jouen, Emmanuel; Ah-You, Nathalie; Lefeuvre, Pierre; Chiroleu, Frédéric; Gagnevin, Lionel; Pruvost, Olivier

    2010-03-01

    Three pathogenic variants (i.e. pathotypes) have been described within Xanthomonas citri pv. citri, the causal agent of Asiatic citrus canker. Pathotype A strains naturally infect a wide range of Citrus species and members of some related genera. In contrast, pathotypes A* and A(w) have narrow host ranges within the genus Citrus and have been isolated from Mexican lime (Citrus aurantifolia L.) and from Mexican lime and alemow (Citrus macrophylla L.), respectively. We used amplified fragment length polymorphism (AFLP) and multilocus sequence analysis (MLSA) based on four partial housekeeping gene sequences (atpD, dnaK, efp and gyrB ) for the genotypic classification of Xanthomonas citri pv. citri and the poorly characterized citrus pathogen Xanthomonas campestris pv. bilvae. A Mantel test showed that genetic distances derived from AFLP and MLSA were highly correlated. X. campestris pv. bilvae showed a close relatedness to the type strain of X. citri, indicating that this pathovar should be reclassified as X. citri pv. bilvae. All pathotype A* and A(w) strains were most closely related to X. citri pv. citri strains with a wide host range (pathotype A), confirming previous DNA-DNA hybridization data. Pathotype A(w) should be considered a junior synonym of pathotype A* on the basis of pathogenicity tests, AFLP, MLSA and PCR using pathovar-specific primers. Evolutionary genome divergences computed from AFLP data suggested that pathotype A* (including A(w) strains) is a group of strains that shows a wider genetic diversity than pathotype A.

  14. 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.

  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.

  17. 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

  18. Scientific Opinion on the request from the USA regarding export of Florida citrus fruit to the EU

    DEFF Research Database (Denmark)

    Baker, R.; Candresse, T.; Dormannsné Simon, E.

    2011-01-01

    Following a request from the EU Commission, the EFSA PLH Panel conducted a scientific opinion on risk analysis and supporting documents provided by APHIS/USDA in support of the request to remove the Union's plant health import requirement that citrus fruit imported into the EU be sourced from...... groves where, since the beginning of the last cycle of vegetation no symptoms of citrus canker were observed, neither in their vicinities. The PHL Panel concluded that the transmission of Xanthomonas citri subsp. citri (Xcc) on asymptomatic citrus fruit was more likely when the fruit were collected from...

  19. 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.

  20. Scientific Opinion on the risk to plant health of Xanthomonas citri pv. citri and Xanthomonas citri pv. aurantifolii for the EU territory

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Plant Health (PLH

    2014-02-01

    Full Text Available 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 systematically identified and evaluated. The strains of X. campestris pathogenic to citrus have been reclassified as four distinct infraspecific taxa within two species: X. citri and X. alfalfae. Only two pathovars (X. citri pv. citri and X. citri pv. aurantifolii are responsible for the citrus bacterial canker thatpresents a major risk for the citrus industry in the EU. Seven entry pathways have been identified and evaluated. The likelihood of entry was rated unlikely for fruit, very likely for fruit plants for planting, moderately likely for ornamental plants for planting and unlikely for leaves and twigs. The uncertainty of probability of entry was rated as high. The probability of establishment was rated as moderately likely to likely with a medium uncertainty because host plants are widely present in EU areas where environmental conditions are suitable. Once established, spread would be likely with a low uncertainty. The impact of the disease, even if control measures are applied, was rated as moderate to major with a medium uncertainty. The disease would cause yield losses in areas where citrus is the main crop, increase the need for control measures and create environmental problems.The combined EU regulations have been shown to be effective in preventing the introduction of X. citri pv. citri or X. citri pv. aurantifolii in the EU, as no outbreaks of citrus canker in the EU territory have been reported.

  1. Resistance to Citrus Canker in Key/Mexican Lime Induced by β-Aminobutyric Acid and Green Tea

    National Research Council Canada - National Science Library

    B. Beheshti; G. R. Sharifi-Sirchi; M. Mansouri; A. Hosseinipour; N. L. Schlaich

    2011-01-01

    .... To improve control of this disease, lime (Citrus aurantifolia) plants inoculated with Xcc were treated with β-Aminobutyric Acid (BABA), ascorbic acid (vitamin C), thiamin (vitamin B1), green tea (Camellia sinensis...

  2. 植物内生菌对柑橘溃疡病的生物防治作用及应用前景%Biological Control Effect of Plant Endophyte on Citrus Bacterial Canker Disease and Its Prospects

    Institute of Scientific and Technical Information of China (English)

    金玲莉; 匡全; 王彦波

    2012-01-01

    This paper summarized the disease -resistant mechanism and biological control effect of plant endophyte, discussed the mechanism and superiority of plant endophyte in the control of citrus bacterial canker disease, and looked forward its application in the biological control.%从植物内生菌的抗病机理及生物防治病害作用方面综述了利用植物内生菌防治柑橘溃疡病的机理与优势,并对其生物防治应用前景进行了展望.

  3. 75 FR 34419 - Notice of Revision and Request for Extension of Approval of an Information Collection; Citrus...

    Science.gov (United States)

    2010-06-17

    ... canker is a plant disease that affects plant and plant parts, including fresh fruit of citrus and citrus... Information Collection; Citrus Canker; Interstate Movement of Regulated Nursery Stock and Fruit from... nursery stock and fruit from quarantined areas to prevent the spread of citrus canker and to request...

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  7. 叶片微形态结构特征与柑桔溃疡病抗性的关系%Analysis of Relationship between Citrus Canker Resistance and Leaf Micro-morphological Characteristics

    Institute of Scientific and Technical Information of China (English)

    李敏; 段硕; 李中安; 周彦; 周常勇; 谭锦; 彭耀武

    2013-01-01

    In order to reveal the relationship between leaf micro-morphological characteristics and citrus canker resistance, four citrus genotypes i. e. Luofukumquat, NO. 3 ponkan, Newhall navel and Star Ruby grapefruit with high resistance, resistance, tolerance and high susceptibility, respectively, have been selected in this study. Subsequently, the anatomical structure and stomata in the lower epidermis of mature leaves were observed using scanning electron microscopy, resin embedded semi thin section etc. The healthy leaves were immersed in canker bacteria suspension culture solution for 2 hours, and then the number of bacteria inside of leaf tissue entered through stomata was counted by method of bacteria isolation. The results showed that the resistance of these four citrus genotypes to citrus canker was obviously different. Similarly, the size and density of stomata, thickness of blade, palisade tissue, spongy tissue and lower epidermis were varied considerably among these four citrus genotypes, of which the density of stomata was significantly different. The Star Ruby grapefruit was found to have the highest number of bacteria inside of leaves which were immersed in canker bacteria suspension culture solution, followed by Newhall navel, NO. 3 ponkan and Luofukumquat, this was significantly correlated with stomata density. The results suggested that the stomatal density in abaxial leaf epidermis can be used as a prediction marker for disease resistance.%为了研究叶片微结构特征与柑桔溃疡病抗性的关系,选择对柑桔溃疡病具有高抗(罗浮金柑)、抗(新生系3号椪柑)、耐(纽荷尔脐橙)和高感(星路比葡萄柚)特性的4个品种为试材,在室内涂抹接种验证抗病性的基础上,采用扫描电镜及树脂包埋半薄切片等技术对成熟叶片的解剖结构及下表皮进行观测,并采用细菌分离法测检各品种健康叶片浸泡接种病菌侵入数量.结果表明:4个品种对柑桔溃疡病抗性差异明

  8. 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.

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

    Directory of Open Access Journals (Sweden)

    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

  10. 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

  11. 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.

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

    Directory of Open Access Journals (Sweden)

    Yun Zhao

    Full Text Available 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.

  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. Field Efficacy of Germicides Against Citrus Canker in Navel Orange%几种药剂防治脐橙溃疡病田间药效试验

    Institute of Scientific and Technical Information of China (English)

    薛巧英

    2016-01-01

    通过选择5种药剂,在屏南县康里村大塆脐橙园开展了脐橙溃疡病防治试验。试验结果表明:5种药剂对脐橙春梢、夏梢、秋梢和果实的溃疡病均有防效,依据防效提出春梢、夏梢以20%噻菌铜(龙克菌)、47%春雷∙王铜等铜制剂防治为主,秋梢及果实膨大期至果实成熟前以靓果安等生物制剂为主,铜制剂为辅的防治方针,以期为屏南脐橙溃疡病的防治提供参考。%Experiments of five kinds of drugs against navel orange canker were carried out in Dawan Navel Orange Field, Kangli Village, Pingnan County. The results showed that those five drugs all showed control effects on navel orange canker on the spring shoots, summer shoots, autumn shoots and fruits. According to the control effects, guiding principles were put forward as follows: Cupper fungicides like 20 percent of thiodiazole­copper and 47 percent of kasugamycin∙copper oxychloride, could be preferred for the spring shoots and summer shoots;biological agents like Liangguoan could be preferred for autumn shoots and from the period of fruit expanding to its maturation;copper fungicides as the first prevention, biological agents the second. These provide reference to the control of navel orange canker in Pingnan County.

  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. 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.

  18. Construction of EGFP-labeling system for visualizing the infection process of Xanthomonas axonopodis pv. citri in planta.

    Science.gov (United States)

    Liu, Li-Ping; Deng, Zi-Niu; Qu, Jin-Wang; Yan, Jia-Wen; Catara, Vittoria; Li, Da-Zhi; Long, Gui-You; Li, Na

    2012-09-01

    Xanthomonas axonopodis pv. citri (Xac) is the causal agent of citrus bacterial canker, an economically important disease to world citrus industry. To monitor the infection process of Xac in different citrus plants, the enhanced green florescent protein (EGFP) visualizing system was constructed to visualize the propagation and localization in planta. First, the wild-type Xac was isolated from the diseased leaves of susceptible 'Bingtang' sweet orange, and then the isolated Xac was labeled with EGFP by triparental mating. After PCR identification, the growth kinetics and pathogenicity of the transformants were analyzed in comparison with the wild-type Xac. The EGFP-labeled bacteria were inoculated by spraying on the surface and infiltration in the mesophyll of 'Bingtang' sweet orange leaves. The bacterial cell multiplication and diffusion processes were observed directly under confocal laser scanning microscope at different intervals after inoculation. The results indicated that the EGFP-labeled Xac releasing clear green fluorescence light under fluorescent microscope showed the infection process and had the same pathogenicity as the wild type to citrus. Consequently, the labeled Xac demonstrated the ability as an efficient tool to monitor the pathogen infection.

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

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    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. Analysis of Antimicrobial Activities and Biological Characters of Citrus Antagonism Endophytic Bacteria%柑橘拮抗内生细菌的抑菌活性及生物学性状分析

    Institute of Scientific and Technical Information of China (English)

    金玲莉; 涂娟; 王彦波; 曾明; 杜玉标

    2015-01-01

    From Nanfeng orange leaves and healthy onion’s plant tissue extracts, 3 endophytic strains with antagonism against citrus bacterial canker disease [Xanthomonas campestris pv. Citri (Hasse) Dye] were screened as strains Bb1, Bb2 and YC1. Through antimicrobial activity tests of antagonistic strains, it was obtained that 3 strains had very good inhibitory effects on citrus canker, and finally, their biological characters were studied.%从南丰蜜桔叶片和洋葱的健康植物组织提取液中筛选出3株对柑橘溃疡病[Xanthomonas campestris pv.Citri(Hasse)Dye]有拮抗作用的内生菌株Bb1、Bb2和YC1,通过拮抗菌株的抑菌活性试验得出3株菌株对柑橘溃疡病均有较好的抑制效果,并对其生物学性状进行研究分析。

  1. Genome-wide mutagenesis of Xanthomonas axonopodis pv. citri reveals novel genetic determinants and regulation mechanisms of biofilm formation.

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    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

  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. Monitoramento da expressão gênica de Xanthomonas axonopodis pv. citri em diferentes condições ambientais

    OpenAIRE

    2003-01-01

    The bacterium Xanthomonas axonopodis pv. citri is a pathogen causing citric canker that compromises part of the orange production in the State of São Paulo, with negative consequences for the economy of the State and the Country. For the future control of citric canker, several investigators participated in the Xanthomonas Genome Project in order to determine the gene set of this bacterium and to contribute to the identification of the genes involved in its pathogenicity. In this respect, the...

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

    Directory of Open Access Journals (Sweden)

    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.

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

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    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

  6. 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.

  7. Deciphering the regulon of a GntR family regulator via transcriptome and ChIP-exo analyses and its contribution to virulence in Xanthomonas citri.

    Science.gov (United States)

    Zhou, Xiaofeng; Yan, Qing; Wang, Nian

    2017-02-01

    Xanthomonas contains a large group of plant-associated species, many of which cause severe diseases on important crops worldwide. Six gluconate-operon repressor (GntR) family transcriptional regulators are predicted in Xanthomonas, one of which, belonging to the YtrA subfamily, plays a prominent role in bacterial virulence. However, the direct targets and comprehensive regulatory profile of YtrA remain unknown. Here, we performed microarray and high-resolution chromatin immunoprecipitation-exonuclease (ChIP-exo) experiments to identify YtrA direct targets and its DNA binding motif in X. citri ssp. citri (Xac), the causal agent of citrus canker. Integrative microarray and ChIP-exo data analysis revealed that YtrA directly regulates three operons by binding to a palindromic motif GGTG-N16 -CACC at the promoter region. A similar palindromic motif and YtrA homologues were also identified in many other bacteria, including Stenotrophomonas, Pseudoxanthomonas and Frateuria, indicating a widespread phenomenon. Deletion of ytrA in Xac abolishes bacterial virulence and induction of the hypersensitive response (HR). We found that YtrA regulates the expression of hrp/hrc genes encoding the bacterial type III secretion system (T3SS) and controls multiple biological processes, including motility and adhesion, oxidative stress, extracellular enzyme production and iron uptake. YtrA represses the expression of its direct targets in artificial medium or in planta. Importantly, over-expression of yro3, one of the YtrA directly regulated operons which contains trmL and XAC0231, induced weaker canker symptoms and down-regulation of hrp/hrc gene expression, suggesting a negative regulation in Xac virulence and T3SS. Our study has significantly advanced the mechanistic understanding of YtrA regulation and its contribution to bacterial virulence. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  8. Unravelling potential virulence factor candidates in Xanthomonas citri. subsp. citri by secretome analysis

    Directory of Open Access Journals (Sweden)

    Rafael M. Ferreira

    2016-02-01

    Full Text Available Citrus canker is a major disease affecting citrus production in Brazil. It’s mainly caused by Xanthomonas citri subsp. citri strain 306 pathotype A (Xac. We analysed the differential expression of proteins secreted by wild type Xac and an asymptomatic mutant for hrpB4 (ΔhrpB4 grown in Nutrient Broth (NB and a medium mimicking growth conditions in the plant (XAM1. This allowed the identification of 55 secreted proteins, of which 37 were secreted by both strains when cultured in XAM1. In this secreted protein repertoire, the following stand out: Virk, Polyphosphate-selective porin, Cellulase, Endoglucanase, Histone-like protein, Ribosomal proteins, five hypothetical proteins expressed only in the wild type strain, Lytic murein transglycosylase, Lipoprotein, Leucyl-tRNA synthetase, Co-chaperonin, Toluene tolerance, C-type cytochrome biogenesis membrane protein, Aminopeptidase and two hypothetical proteins expressed only in the ΔhrpB4 mutant. Furthermore, Peptidoglycan-associated outer membrane protein, Regulator of pathogenicity factor, Outer membrane proteins, Endopolygalacturonase, Chorismate mutase, Peptidyl-prolyl cis-trans isomerase and seven hypothetical proteins were detected in both strains, suggesting that there was no relationship with the secretion mediated by the type III secretory system, which is not functional in the mutant strain. Also worth mentioning is the Elongation factor Tu (EF-Tu, expressed only the wild type strain, and Type IV pilus assembly protein, Flagellin (FliC and Flagellar hook-associated protein, identified in the wild-type strain secretome when grown only in NB. Noteworthy, that FliC, EF-Tu are classically characterized as PAMPs (Pathogen-associated molecular patterns, responsible for a PAMP-triggered immunity response. Therefore, our results highlight proteins potentially involved with the virulence. Overall, we conclude that the use of secretome data is a valuable approach that may bring more knowledge of the

  9. Sensitivity to copper in Xanthomonas campestris pv. viticola

    OpenAIRE

    2009-01-01

    ABSTRACT Bacterial canker, caused by Xanthomonas campestris pv. viticola, affects grapevines in the irrigated areas of the São Francisco river valley, in the states of Pernambuco and Bahia. Several practices for disease management have been adopted including copper sprays.This is the only available chemical control method and most frequently used in the areas affected by the disease. The objective of this work was to determine the sensitivity to copper of strains of X. campestris pv. vi...

  10. Management of apple anthracnose canker

    Science.gov (United States)

    Apple anthracnose (caused by Neofabraea malicorticis anamorph Cryptosporiopsis curvispora) is a fungal disease that causes cankers on trees and ‘Bull’s-eye rot’ on fruit. In western Washington, it is the canker phase of apple anthracnose that is considered most serious as it can result in death of ...

  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. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Science.gov (United States)

    2010-01-01

    ...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-17 Funds for the replacement of certified citrus... 7 Agriculture 5 2010-01-01 2010-01-01 false Funds for the replacement of certified citrus...

  13. Xanthomonas citri subsp. citri surface proteome by 2D-DIGE: Ferric enterobactin receptor and other outer membrane proteins potentially involved in citric host interaction.

    Science.gov (United States)

    Carnielli, Carolina Moretto; Artier, Juliana; de Oliveira, Julio Cezar Franco; Novo-Mansur, Maria Teresa Marques

    2017-01-16

    Xanthomonas citri subsp. citri (XAC) is the causative agent of citrus canker, a disease of great economic impact around the world. Understanding the role of proteins on XAC cellular surface can provide new insights on pathogen-plant interaction. Surface proteome was performed in XAC grown in vivo (infectious) and in vitro (non-infectious) conditions, by labeling intact cells followed by cellular lysis and direct 2D-DIGE analysis. Seventy-nine differential spots were analyzed by mass spectrometry. Highest relative abundance for in vivo condition was observed for spots containing DnaK protein, 60kDa chaperonin, conserved hypothetical proteins, malate dehydrogenase, phosphomannose isomerase, and ferric enterobactin receptors. Elongation factor Tu, OmpA-related proteins, Oar proteins and some Ton-B dependent receptors were found in spots decreased in vivo. Some proteins identified on XAC's surface in infectious condition and predicted to be cytoplasmic, such as DnaK and 60KDa chaperonin, have also been previously found at cellular surface in other microorganisms. This is the first study on XAC surface proteome and results point to mediation of molecular chaperones in XAC-citrus interaction. The approach utilized here can be applied to other pathogen-host interaction systems and help to achieve new insights in bacterial pathogenicity toward promising targets of biotechnological interest.

  14. Characterization of bacteriophages Cp1 and Cp2, the strain-typing agents for Xanthomonas axonopodis pv. citri.

    Science.gov (United States)

    Ahmad, Abdelmonim Ali; Ogawa, Megumi; Kawasaki, Takeru; Fujie, Makoto; Yamada, Takashi

    2014-01-01

    The strains of Xanthomonas axonopodis pv. citri, the causative agent of citrus canker, are historically classified based on bacteriophage (phage) sensitivity. Nearly all X. axonopodis pv. citri strains isolated from different regions in Japan are lysed by either phage Cp1 or Cp2; Cp1-sensitive (Cp1(s)) strains have been observed to be resistant to Cp2 (Cp2(r)) and vice versa. In this study, genomic and molecular characterization was performed for the typing agents Cp1 and Cp2. Morphologically, Cp1 belongs to the Siphoviridae. Genomic analysis revealed that its genome comprises 43,870-bp double-stranded DNA (dsDNA), with 10-bp 3'-extruding cohesive ends, and contains 48 open reading frames. The genomic organization was similar to that of Xanthomonas phage phiL7, but it lacked a group I intron in the DNA polymerase gene. Cp2 resembles morphologically Escherichia coli T7-like phages of Podoviridae. The 42,963-bp linear dsDNA genome of Cp2 contained terminal repeats. The Cp2 genomic sequence has 40 open reading frames, many of which did not show detectable homologs in the current databases. By proteomic analysis, a gene cluster encoding structural proteins corresponding to the class III module of T7-like phages was identified on the Cp2 genome. Therefore, Cp1 and Cp2 were found to belong to completely different virus groups. In addition, we found that Cp1 and Cp2 use different molecules on the host cell surface as phage receptors and that host selection of X. axonopodis pv. citri strains by Cp1 and Cp2 is not determined at the initial stage by binding to receptors.

  15. 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.

  16. Scientific Opinion on the request from the USA regarding export of Florida citrus fruit to the EU

    DEFF Research Database (Denmark)

    Baker, R.; Candresse, T.; Dormannsné Simon, E.

    2011-01-01

    Following a request from the EU Commission, the EFSA PLH Panel conducted a scientific opinion on risk analysis and supporting documents provided by APHIS/USDA in support of the request to remove the Union's plant health import requirement that citrus fruit imported into the EU be sourced from...... of spread of citrus canker through the fruit pathway. Some data provided in the APHIS-USDA documents support that citrus fruit remain a conceptually possible pathway for transmitting and establishing citrus canker disease. The PLH Panel agrees that transmission of Xcc from infected fruit to a susceptible...

  17. Bacterial canker resistance in tomato

    NARCIS (Netherlands)

    Sen, Y.

    2014-01-01

    Clavibacter michiganensis subsp. michiganensis (Cmm) is the pathogen causing bacterial  canker in tomato. The disease was described for the first time in 1910 in Michigan, USA. Cmmis considered the most harmful bacteria threatening tomato. Disease transmission occurs via seed and symptoms becom

  18. 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

  19. Occurrence, molecular characterisation, and pathogenicity of Neoscytalidium dimidiatum on Citrus in Italy

    NARCIS (Netherlands)

    Polizzi, G.; Aiello, D.; Castello, I.; Vitale, A.; Groenewald, J.Z.; Crous, P.W.; Gentile, A.; La Malfa, S.

    2011-01-01

    During 2008 and 2009, a new disease was noticed in eastern Sicily (Italy) in two re-grafted citrus orchards (Citrus sinensis (L.) Osbeck) on sour orange rootstock. Symptoms consisted of blight of vigorously growing shoots and a sooty canker on shoots and rootstock trunks. A Scytalidium-like fungus w

  20. Occurrence, molecular characterisation, and pathogenicity of Neoscytalidium dimidiatum on citrus in Italy

    NARCIS (Netherlands)

    Polizzi, G.; Aiello, D.; Castello, I.; Vitale, A.; Groenewald, J.Z.; Crous, P.W.

    2011-01-01

    During 2008 and 2009, a new disease was noticed in eastern Sicily (Italy) in two re-grafted citrus orchards (Citrus sinensis (L.) Osbeck) on sour orange rootstock. Symptoms consisted of blight of vigorously growing shoots and a sooty canker on shoots and rootstock trunks. A Scytalidium-like fungus w

  1. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Commercial citrus-producing areas. 301.75-5 Section 301.75-5 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of...

  2. 7 CFR 301.75-15 - Funds for the replacement of commercial citrus trees.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Funds for the replacement of commercial citrus trees. 301.75-15 Section 301.75-15 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...

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

    Science.gov (United States)

    Tondo, María Laura; Musumeci, Matías A; Delprato, María Laura; Ceccarelli, Eduardo A; Orellano, Elena G

    2011-01-01

    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. citri and

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

    Directory of Open Access Journals (Sweden)

    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

  5. Comparison of FTIR spectra between Huanglongbing (citrus greening) and other citrus maladies.

    Science.gov (United States)

    Hawkins, Samantha A; Park, Bosoon; Poole, Gavin H; Gottwald, Tim R; Windham, William R; Albano, Joseph; Lawrence, Kurt C

    2010-05-26

    Fourier transform infrared (FTIR) spectroscopy has the ability to quickly identify the presence of specific carbohydrates in plant materials. The presence of the disease huanglongbing (HLB) in the leaves of infected citrus plants has a distinctive spectrum that can be used to distinguish an infected plant from a healthy plant. However, many citrus diseases display similar visible symptoms and are of concern to citrus growers. In this study several citrus diseases (citrus leaf rugose virus, citrus tristeza virus, citrus psorosis virus, and Xanthomonas axonopodis ) and nutrient deficiencies (iron, copper, zinc, manganese, and magnesium) were compared with HLB using FTIR spectroscopy to determine if the spectra alone can be used to identify plants that are infected with HLB instead of another disease. The results indicate that the spectra of some diseases and deficiencies more closely resemble those of apparently healthy plants and some share the carbohydrate transformation that has been seen in the spectra of HLB-infected plants.

  6. The weathervane model, a functional and structural organization of the two-component alkanesulfonate oxidoreductase SsuD from Xanthomonas citri

    Energy Technology Data Exchange (ETDEWEB)

    Pegos, V.R. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil); Oliveira, P.S.L.; Balan, A. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil)

    2012-07-01

    Full text: In Xanthomonas citri, the phytopathogen responsible for the canker citrus disease, we identified in the ssuABCDE operon, genes encoding the alkanesulfonate ABC transporter as well as the two enzymes responsible for oxido reduction of the respective substrates. SsuD and SsuE proteins represent a two-component system that can be assigned to the group of FMNH{sub 2} -dependent monooxygenases. How- ever, despite of the biochemical information about SsuD and SsuE orthologs from Escherichia coli, there is no structural information of how the two proteins work together. In this work, we used ultracentrifugation, SAXS data and molecular modeling to construct a structural/functional model, which consists of eight molecules organized in a weathervane shape. Through this model, SsuD ligand-binding site for NADPH{sub 2} and FMN substrates is clearly exposed, in a way that might allow the protein-protein interactions with SsuE. Moreover, based on molecular dynamics simulations of SsuD in apo state, docked with NADPH{sub 2}, FMN or both substrates, we characterized the residues of the pocket, the mechanism of substrate interaction and transfer of electrons from NADPH{sub 2} to FMN. This is the first report that links functional and biochemical data with structural analyses. (author)

  7. Bacterial canker resistance in tomato

    OpenAIRE

    Sen, Y.

    2014-01-01

    Clavibacter michiganensis subsp. michiganensis (Cmm) is the pathogen causing bacterial  canker in tomato. The disease was described for the first time in 1910 in Michigan, USA. Cmmis considered the most harmful bacteria threatening tomato. Disease transmission occurs via seed and symptoms become visible at least 20 days after infection. Due to its complex strategy and transmission, Cmm is under quarantine regulation in EU and other countries. There is no method to stop disease progress i...

  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

    National Research Council Canada - National Science Library

    María E. Romero; C. Jacqueline Ramallo; L. Daniel Ploper

    2008-01-01

    ... 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...

  9. 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

    OpenAIRE

    María E. Romero; C. Jacqueline Ramallo; L. Daniel Ploper

    2008-01-01

    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) ...

  10. 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.

  11. 76 FR 23449 - Citrus Canker, Citrus Greening, and Asian Citrus Psyllid; Interstate Movement of Regulated...

    Science.gov (United States)

    2011-04-27

    ... analysis, especially any scientific studies that may be pertinent. Protocol Document Based on the... either case, the statement is prominently and legibly displayed. The nursery stock is moved in a... Huanglongbing. Plant Management Network International, Orlando, Florida. Copies available from the individuals...

  12. Dynamics of Cryphonectria hypovirus infection in chestnut blight cankers.

    Science.gov (United States)

    Bryner, Sarah Franziska; Prospero, Simone; Rigling, Daniel

    2014-09-01

    Virulent strains of the chestnut blight fungus Cryphonectria parasitica cause lethal bark cankers on chestnut trees. Infection of C. parasitica with Cryphonectria hypovirus 1 in Europe biologically controls this disease, leading to nonlethal and inactive cankers. Unexpectedly, virus-free C. parasitica strains have been isolated from inactive cankers. In this study, we compared the virulence of virus-infected and virus-free C. parasitica strains isolated from either inactive or active cankers on chestnut seedlings and sprouts. In the seedling experiment, we assessed canker growth and seedling mortality. In the sprout experiment, we also assessed canker growth and made fungal reisolations to determine virus infection and immigration of foreign vegetative compatibility (vc) types over a period of 13 years in a coppice forest. Overall, the virulence of virus-free C. parasitica strains isolated from inactive versus active cankers did not differ. Significant differences were only attributed to virus infection. Virus infection and fungal strain composition in cankers changed over time. Foreign vc types immigrated into cankers and virus-free cankers became virus-infected within a few years. Most of the cankers were callused over time and became inactive. However, we observed that the virus did not always persist in these cankers. This study demonstrates that virus spread occurs effectively in European chestnut forests and that this biocontrol system is highly dynamic.

  13. 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)

  14. First report of Pestalotiopsis diospyri causing canker on persimmon trees

    Directory of Open Access Journals (Sweden)

    Giselda Alves

    2011-09-01

    Full Text Available During 2006 to 2009 season symptoms of a canker disease were observed on twigs and branches of young and mature persimmon trees (Diospyros kaki L. cv. Fuyu in the States of Santa Catarina and Paraná in the Southern Brazil. The cankers result in severe damage and reduced production. Isolations from the margins of these cankers revealed a genus of Pestalotiopsis. Koch's postulates were confirmed using two isolates of the pathogen which was identified as Pestalotiopsis diospyri.

  15. Thousand cankers disease: Geosmithia morbida spores isolated from a weevil

    Science.gov (United States)

    Michele Warmund; Jerry. Van Sambeek

    2014-01-01

    Recently, Geosmithia morbida, the canker-causing fungus associated with thousand cankers disease, was isolated from Stenomimus pallidus weevils found on two stressed black walnut trees in Yellowwood State Forest near Nashville, Indiana. This is the first report of Geosmithia fungus occurring on an insect other than the walnut twig beetle (Pityophthorus juglandis)....

  16. Apple anthracnose canker life cycle and disease cycle

    Science.gov (United States)

    Apple anthracnose [caused by Neofabraea malicorticis (H.S. Jacks) anamorph Cryptosporiopsis curvispora (Peck)] is a fungal disease that impacts apple production. The pathogen produces cankers on trees as well as a rot on the fruit known as ‘Bull’s-eye rot’. The cankers cause severe damage to trees...

  17. Construction of citrus gene coexpression networks from microarray data using random matrix theory.

    Science.gov (United States)

    Du, Dongliang; Rawat, Nidhi; Deng, Zhanao; Gmitter, Fred G

    2015-01-01

    After the sequencing of citrus genomes, gene function annotation is becoming a new challenge. Gene coexpression analysis can be employed for function annotation using publicly available microarray data sets. In this study, 230 sweet orange (Citrus sinensis) microarrays were used to construct seven coexpression networks, including one condition-independent and six condition-dependent (Citrus canker, Huanglongbing, leaves, flavedo, albedo, and flesh) networks. In total, these networks contain 37 633 edges among 6256 nodes (genes), which accounts for 52.11% measurable genes of the citrus microarray. Then, these networks were partitioned into functional modules using the Markov Cluster Algorithm. Significantly enriched Gene Ontology biological process terms and KEGG pathway terms were detected for 343 and 60 modules, respectively. Finally, independent verification of these networks was performed using another expression data of 371 genes. This study provides new targets for further functional analyses in citrus.

  18. Citrus pulp for cattle.

    Science.gov (United States)

    Arthington, John D; Kunkle, William E; Martin, Amy M

    2002-07-01

    Citrus pulp is classified as an energy concentrate by-product feed. Citrus by-products fed to beef cattle include citrus molasses, citrus meal, wet citrus pulp, dried citrus pulp, and pelleted citrus pulp; however, in current production systems, pulp (wet, dry, and pelleted) is the only by-product commonly used. Citrus pulp production in the United States is limited to specific subtropical regions, of which south central Florida remains the largest with additional production in California and Texas.

  19. Overexpression of a citrus NDR1 ortholog increases disease resistance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Hua eLu

    2013-06-01

    Full Text Available Emerging devastating diseases, such as Huanglongbing (HLB and citrus canker, have caused tremendous losses to the citrus industry worldwide. Genetic engineering is a powerful approach that could allow us to increase citrus resistance against these diseases. The key to the success of this approach relies on a thorough understanding of defense mechanisms of citrus. Studies of Arabidopsis and other plants have provided a framework for us to better understand defense mechanisms of citrus. Salicylic acid (SA is a key signaling molecule involved in basal defense and resistance (R-gene mediated defense against broad-spectrum pathogens. The Arabidopsis gene NDR1 is a positive regulator of SA accumulation and is specifically required for signaling mediated by a subset of R genes upon recognition of their cognate pathogen effectors. Our bioinformatic analysis identified an ortholog of NDR1 from citrus, ctNDR1. Overexpression of ctNDR1 complemented susceptibility conferred by the Arabidopsis ndr1-1 mutant to Pseudomonas syringae strains and also led to enhanced resistance to an oomycete pathogen Hyaloperonospora arabidopsidis. Such heightened resistance is associated with increased SA production and expression of the defense marker gene PR1. In addition, we found that expression of PR1 and accumulation of SA were induced to modest levels in citrus infected with Candidatus Liberibacter asiaticus, the bacterial pathogen associated with HLB disease. Thus, our data suggest that ctNDR1 is a functional ortholog of Arabidopsis NDR1. Since Ca. L. asiaticus infection only activates modest levels of defense responses in citrus, we propose that genetically increasing SA/NDR1-mediated pathways could potentially lead to enhanced resistance against HLB, citrus canker, and other destructive diseases challenging global citrus production.

  20. Xcc-facilitated agroinfiltration of citrus leaves: a tool for rapid functional analysis of transgenes in citrus leaves.

    Science.gov (United States)

    Jia, Hongge; Wang, Nian

    2014-12-01

    Xanthomonas citri subsp. citri pretreatment before agroinfiltration could significantly promote transient expression in citrus leaves which were previously recalcitrant to agroinfiltration. Transient expression via agroinfiltration is widely used in biotechnology but remains problematic in many economically important plants. Xanthomonas citri subsp. citri (Xcc)-facilitated agroinfiltration was employed to promote transient protein expression in Valencia sweet orange leaves, which are recalcitrant to agroinfiltration. However, it is unclear whether Xcc-facilitated agroinfiltration has broad application, i.e., whether Xcc-facilitated agroinfiltration could be used on other citrus varieties. In addition, we intended to investigate whether Xcc-facilitated agroinfiltration could be used to hasten transgene function assays, e.g., Cre/lox system and Cas9/sgRNA system. In this report, Xcc-facilitated agroinfiltration was further exploited to enhance β-glucuronidase (GUS) expression in five citrus varieties. Xcc-facilitated agroinfiltration also significantly increased GFP expression in six citrus varieties tested. Both GUS and GFP assays indicated that Xcc-facilitated agroinfiltration had the best performance in grapefruit. After Xcc-facilitated agroinfiltration was carried out in grapefruit, protoplast analysis of the transformed cells indicated that there were more than 20 % leaf cells expressing GFP. In grapefruit, usefulness of Xcc-facilitated agroinfiltration was assayed in three case studies: (1) fast functional analysis of Cre/lox system, (2) the heat shock regulation of HSP70B promoter derived from Arabidopsis, and (3) Cas9/sgRNA-mediated genome modification.

  1. Citrus leprosis research update

    Science.gov (United States)

    Citrus leprosis is one of the oldest citrus diseases, but is also one of the most important emerging citrus diseases in South and Central America, and it is apparently spreading northward towards the U.S. Research in our labs and by others has shown that citrus leprosis disease is caused by a compl...

  2. Detection of Anomalies in Citrus Leaves Using Laser-Induced Breakdown Spectroscopy (LIBS).

    Science.gov (United States)

    Sankaran, Sindhuja; Ehsani, Reza; Morgan, Kelly T

    2015-08-01

    Nutrient assessment and management are important to maintain productivity in citrus orchards. In this study, laser-induced breakdown spectroscopy (LIBS) was applied for rapid and real-time detection of citrus anomalies. Laser-induced breakdown spectroscopy spectra were collected from citrus leaves with anomalies such as diseases (Huanglongbing, citrus canker) and nutrient deficiencies (iron, manganese, magnesium, zinc), and compared with those of healthy leaves. Baseline correction, wavelet multivariate denoising, and normalization techniques were applied to the LIBS spectra before analysis. After spectral pre-processing, features were extracted using principal component analysis and classified using two models, quadratic discriminant analysis and support vector machine (SVM). The SVM resulted in a high average classification accuracy of 97.5%, with high average canker classification accuracy (96.5%). LIBS peak analysis indicated that high intensities at 229.7, 247.9, 280.3, 393.5, 397.0, and 769.8 nm were observed of 11 peaks found in all the samples. Future studies using controlled experiments with variable nutrient applications are required for quantification of foliar nutrients by using LIBS-based sensing.

  3. A plant natriuretic peptide-like gene in the bacterial pathogen Xanthomonas axonopodis may induce hyper-hydration in the plant host: a hypothesis of molecular mimicry

    Directory of Open Access Journals (Sweden)

    Sayed Muhammed

    2004-03-01

    Full Text Available Abstract Background Plant natriuretic peptides (PNPs are systemically mobile molecules that regulate homeostasis at nanomolar concentrations. PNPs are up-regulated under conditions of osmotic stress and PNP-dependent processes include changes in ion transport and increases of H2O uptake into protoplasts and whole tissue. Presentation of the hypothesis The bacterial citrus pathogen Xanthomonas axonopodis pv. Citri str. 306 contains a gene encoding a PNP-like protein. We hypothesise that this bacterial protein can alter plant cell homeostasis and thus is likely to represent an example of molecular mimicry that enables the pathogen to manipulate plant responses in order to bring about conditions favourable to the pathogen such as the induced plant tissue hyper-hydration seen in the wet edged lesions associated with Xanthomonas axonopodis infection. Testing the hypothesis We found a Xanthomonas axonopodis PNP-like protein that shares significant sequence similarity and identical domain organisation with PNPs. We also observed a significant excess of conserved residues between the two proteins within the domain previously identified as being sufficient to induce biological activity. Structural modelling predicts identical six stranded double-psi β barrel folds for both proteins thus supporting the hypothesis of similar modes of action. No significant similarity between the Xanthomonas axonopodis protein and other bacterial proteins from GenBank was found. Sequence similarity of the Xanthomonas axonopodis PNP-like protein with the Arabidopsis thaliana PNP (AtPNP-A, shared domain organisation and incongruent phylogeny suggest that the PNP-gene may have been acquired by the bacteria in an ancient lateral gene transfer event. Finally, activity of a recombinant Xanthomonas axonopodis protein in plant tissue and changes in symptoms induced by a Xanthomonas axonopodis mutant with a knocked-out PNP-like gene will be experimental proof of molecular mimicry

  4. Meningitis due to Xanthomonas maltophilia.

    Directory of Open Access Journals (Sweden)

    Girijaratnakumari T

    1993-07-01

    Full Text Available During 1st week of post-operative period, a 28 year old female patient operated for left cerebellopontine angle tumor, continued to get fever. Lumbar puncture did not reveal any organisms. She responded to ciprofloxacin. Two months later, she was readmitted with signs and symptoms of meningitis. The CSF tapped on lumbar puncture grew Xanthomonas maltophilia, Gram negative bacilli, sensitive to various antibiotics, ciprofloxacin being one of them. The patient was given ciprofloxacin for 3 weeks. On follow up, a year later she was found to be asymptomatic.

  5. 76 FR 52543 - European Larch Canker; Expansion of Regulated Areas

    Science.gov (United States)

    2011-08-23

    ... Areas AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Interim rule and request for comments. SUMMARY: We are amending the domestic quarantine regulations to expand the regulated area for European larch canker to include additional areas in Maine. We are also correcting some...

  6. Genetic Transformation in Citrus

    Directory of Open Access Journals (Sweden)

    Dicle Donmez

    2013-01-01

    Full Text Available Citrus is one of the world’s important fruit crops. Recently, citrus molecular genetics and biotechnology work have been accelerated in the world. Genetic transformation, a biotechnological tool, allows the release of improved cultivars with desirable characteristics in a shorter period of time and therefore may be useful in citrus breeding programs. Citrus transformation has now been achieved in a number of laboratories by various methods. Agrobacterium tumefaciens is used mainly in citrus transformation studies. Particle bombardment, electroporation, A. rhizogenes, and a new method called RNA interference are used in citrus transformation studies in addition to A. tumefaciens. In this review, we illustrate how different gene transformation methods can be employed in different citrus species.

  7. Bayesian analysis for inference of an emerging epidemic: citrus canker in urban landscapes

    Science.gov (United States)

    Outbreaks of infectious diseases require a rapid response from policy makers. The strength and efficacy of the responses depend upon available knowledge of the spatial and temporal parameters governing pathogen spread, affecting, amongst others, the predicted severity of the epidemic. Yet, when a ne...

  8. Phomopsis stem canker: a re-emerging threat to sunflowers (Helianthus annuus) in the United States

    Science.gov (United States)

    Phomopsis stem canker frequently causes yield reductions on sunflowers (Helianthus annuus L.) on several continents, including Australia, Russia, Europe and North America. Between 2001 and 2012, the incidence of Phomopsis stem canker has increased 16 fold in the Northern Great Plains of the United...

  9. Citrus Waste Biomass Program

    Energy Technology Data Exchange (ETDEWEB)

    Karel Grohman; Scott Stevenson

    2007-01-30

    Renewable Spirits is developing an innovative pilot plant bio-refinery to establish the commercial viability of ehtanol production utilizing a processing waste from citrus juice production. A novel process based on enzymatic hydrolysis of citrus processing waste and fermentation of resulting sugars to ethanol by yeasts was successfully developed in collaboration with a CRADA partner, USDA/ARS Citrus and Subtropical Products Laboratory. The process was also successfully scaled up from laboratory scale to 10,000 gal fermentor level.

  10. Genomes-based phylogeny of the genus Xanthomonas

    Directory of Open Access Journals (Sweden)

    Rodriguez-R Luis M

    2012-03-01

    Full Text Available Abstract Background The genus Xanthomonas comprises several plant pathogenic bacteria affecting a wide range of hosts. Despite the economic, industrial and biological importance of Xanthomonas, the classification and phylogenetic relationships within the genus are still under active debate. Some of the relationships between pathovars and species have not been thoroughly clarified, with old pathovars becoming new species. A change in the genus name has been recently suggested for Xanthomonas albilineans, an early branching species currently located in this genus, but a thorough phylogenomic reconstruction would aid in solving these and other discrepancies in this genus. Results Here we report the results of the genome-wide analysis of DNA sequences from 989 orthologous groups from 17 Xanthomonas spp. genomes available to date, representing all major lineages within the genus. The phylogenetic and computational analyses used in this study have been automated in a Perl package designated Unus, which provides a framework for phylogenomic analyses which can be applied to other datasets at the genomic level. Unus can also be easily incorporated into other phylogenomic pipelines. Conclusions Our phylogeny agrees with previous phylogenetic topologies on the genus, but revealed that the genomes of Xanthomonas citri and Xanthomonas fuscans belong to the same species, and that of Xanthomonas albilineans is basal to the joint clade of Xanthomonas and Xylella fastidiosa. Genome reduction was identified in the species Xanthomonas vasicola in addition to the previously identified reduction in Xanthomonas albilineans. Lateral gene transfer was also observed in two gene clusters.

  11. Characterization of Xanthomonas axonopodis pv. phaseoli isolates

    NARCIS (Netherlands)

    Nunes, W.M.C.; Corazza, M.J.; De Souza, S.A.C.D.; Tsai, S.M.; Kuramae, E.E.

    2008-01-01

    A simple, quick and easy protocol was standardized for extraction of total DNA of the bacteria Xanthomonas axonopodis pv. phaseoli. The DNA obtained by this method had high quality and the quantity was enough for the Random Amplified Polymorphic DNA (RAPD) reactions with random primers, and

  12. Characterization of Xanthomonas axonopodis pv. phaseoli isolates

    NARCIS (Netherlands)

    Nunes, W.M.C.; Corazza, M.J.; De Souza, S.A.C.D.; Tsai, S.M.; Kuramae, E.E.

    2008-01-01

    A simple, quick and easy protocol was standardized for extraction of total DNA of the bacteria Xanthomonas axonopodis pv. phaseoli. The DNA obtained by this method had high quality and the quantity was enough for the Random Amplified Polymorphic DNA (RAPD) reactions with random primers, and Polymera

  13. Cercosporoid diseases of Citrus.

    Science.gov (United States)

    Huang, Feng; Groenewald, J Z; Zhu, Li; Crous, P W; Li, Hongye

    2015-01-01

    Citrus leaves and fruits exhibiting disease symptoms ranging from greasy spot, yellow spot, small or large brown spot, black dot, and brown dot were sampled from Fujian, Guangdong, Guizhou, Hunan, Jiangxi, Yunnan, Zhejiang provinces and the Guangxi Zhuang Autonomous Region in China. In total 82 isolates representing various cercosporoid genera were isolated from these disease symptoms, which were supplemented with eight Citrus cercosporoid isolates collected from other countries. Based on a morphological and phylogenetic study using sequence data from the nuclear ribosomal DNA's ITS1-5.8S-ITS2 regions (ITS), and partial actin (act), β-tubulin (tub2), 28S nuclear ribosomal RNA (28S rDNA) and translation elongation factor 1-α (tef1) genes, these strains were placed in the following genera: Cercospora, Pallidocercospora, Passalora, Pseudocercospora, Verrucisporota and Zasmidium. All isolates tended to be sterile, except the Zasmidium isolates associated with citrus greasy spot-like symptoms, which subsequently were compared with phylogenetically similar isolates occurring on Citrus and other hosts elsewhere. From these results four Zasmidium species were recognized on Citrus, namely Z. indonesianum on Citrus in Indonesia, Z. fructicola and Z. fructigenum on Citrus in China and Z. citri-griseum, which appears to have a wide host range including Acacia, Citrus, Eucalyptus and Musa, as well as a global distribution.

  14. Certification Programs for Citrus

    Science.gov (United States)

    Citrus certification programs designed to ensure that healthy plants of the highest genetic potential are being planted in the field are the basic building block of an integrated pest management program. Certification programs began for citrus began with the discovery that the diseases were graft t...

  15. Cancro bacteriano da videira: etiologia, epidemiologia e medidas de controle Bacterial canker of grapevine: etiology, epidemiology and control strategies

    Directory of Open Access Journals (Sweden)

    Ana Rosa Peixoto Nascimento

    2004-02-01

    Full Text Available No início de 1998, o cancro bacteriano da videira, causado pela bactéria Xanthomonas campestris pv. viticola, foi detectado pela primeira vez, no Brasil, em parreirais do Submédio São Francisco, onde a doença vem ocasionando prejuízos nas cultivares suscetíveis Red Globe, Itália, Festival, Brasil, Piratininga, Patrícia, Benitaka e Catalunha. Os sintomas, nas folhas, surgem como pontos necróticos (1 a 2mm de diâmetro com ou sem halos amarelados, algumas vezes coalescendo e causando a morte de extensas áreas do limbo foliar. Nas nervuras e pecíolos, nos ramos e ráquis dos frutos, formam-se manchas escuras alongadas que evoluem para fissuras longitudinais de coloração negra conhecidas como cancros. Descoloração vascular é também observada. As bagas são desuniformes em tamanho e cor podendo apresentar lesões necróticas. A disseminação do patógeno ocorre através de material propagativo infectado, material de colheita (contentores, tesouras de poda e raleio, luvas, tratos culturais (desbrota, poda, raleio de bagas, colheita, ventos e chuvas. Apesar da região apresentar um curto período chuvoso, a disseminação da bactéria é mais eficiente durante essa época. Em condições de umidade e temperatura elevadas, o patógeno sobrevive em restos de cultura. Para o controle da doença, recomenda-se o uso de material propagativo sadio, inspeção no campo, poda drástica de órgãos infectados, eliminação de plantas severamente infectadas, condução da época de poda de produção, desinfestação de veículos, de equipamentos e de materiais para poda, utilização de fungicidas protetores cúpricos e tiocarbamatos, e utilização de quebra-ventos para reduzir a disseminação do patógeno.In the begining of 1998, bacterial canker of grapevine, caused by the bacterium Xanthomonas campestris pv. viticola, was detected for the first time in Brazil in vineyards of the “Submédio São Francisco”. Losses in susceptible

  16. Abundance of citrus leafminer larvae on citrus and citrus-related germplasm

    Science.gov (United States)

    The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a key pest in most citrus growing regions worldwide. Adult citrus leafminers oviposit primarily on young elongating flush of citrus as well as other Rutaceae and some ornamental plants. Larvae feed on the epiderm...

  17. Acquisition and Evolution of Plant Pathogenesis–Associated Gene Clusters and Candidate Determinants of Tissue-Specificity in Xanthomonas

    Science.gov (United States)

    Van Sluys, Marie-Anne; White, Frank F.; Ryan, Robert P.; Dow, J. Maxwell; Rabinowicz, Pablo; Salzberg, Steven L.; Leach, Jan E.; Sonti, Ramesh; Brendel, Volker; Bogdanove, Adam J.

    2008-01-01

    Background Xanthomonas is a large genus of plant-associated and plant-pathogenic bacteria. Collectively, members cause diseases on over 392 plant species. Individually, they exhibit marked host- and tissue-specificity. The determinants of this specificity are unknown. Methodology/Principal Findings To assess potential contributions to host- and tissue-specificity, pathogenesis-associated gene clusters were compared across genomes of eight Xanthomonas strains representing vascular or non-vascular pathogens of rice, brassicas, pepper and tomato, and citrus. The gum cluster for extracellular polysaccharide is conserved except for gumN and sequences downstream. The xcs and xps clusters for type II secretion are conserved, except in the rice pathogens, in which xcs is missing. In the otherwise conserved hrp cluster, sequences flanking the core genes for type III secretion vary with respect to insertion sequence element and putative effector gene content. Variation at the rpf (regulation of pathogenicity factors) cluster is more pronounced, though genes with established functional relevance are conserved. A cluster for synthesis of lipopolysaccharide varies highly, suggesting multiple horizontal gene transfers and reassortments, but this variation does not correlate with host- or tissue-specificity. Phylogenetic trees based on amino acid alignments of gum, xps, xcs, hrp, and rpf cluster products generally reflect strain phylogeny. However, amino acid residues at four positions correlate with tissue specificity, revealing hpaA and xpsD as candidate determinants. Examination of genome sequences of xanthomonads Xylella fastidiosa and Stenotrophomonas maltophilia revealed that the hrp, gum, and xcs clusters are recent acquisitions in the Xanthomonas lineage. Conclusions/Significance Our results provide insight into the ancestral Xanthomonas genome and indicate that differentiation with respect to host- and tissue-specificity involved not major modifications or wholesale

  18. Acquisition and evolution of plant pathogenesis-associated gene clusters and candidate determinants of tissue-specificity in xanthomonas.

    Directory of Open Access Journals (Sweden)

    Hong Lu

    Full Text Available BACKGROUND: Xanthomonas is a large genus of plant-associated and plant-pathogenic bacteria. Collectively, members cause diseases on over 392 plant species. Individually, they exhibit marked host- and tissue-specificity. The determinants of this specificity are unknown. METHODOLOGY/PRINCIPAL FINDINGS: To assess potential contributions to host- and tissue-specificity, pathogenesis-associated gene clusters were compared across genomes of eight Xanthomonas strains representing vascular or non-vascular pathogens of rice, brassicas, pepper and tomato, and citrus. The gum cluster for extracellular polysaccharide is conserved except for gumN and sequences downstream. The xcs and xps clusters for type II secretion are conserved, except in the rice pathogens, in which xcs is missing. In the otherwise conserved hrp cluster, sequences flanking the core genes for type III secretion vary with respect to insertion sequence element and putative effector gene content. Variation at the rpf (regulation of pathogenicity factors cluster is more pronounced, though genes with established functional relevance are conserved. A cluster for synthesis of lipopolysaccharide varies highly, suggesting multiple horizontal gene transfers and reassortments, but this variation does not correlate with host- or tissue-specificity. Phylogenetic trees based on amino acid alignments of gum, xps, xcs, hrp, and rpf cluster products generally reflect strain phylogeny. However, amino acid residues at four positions correlate with tissue specificity, revealing hpaA and xpsD as candidate determinants. Examination of genome sequences of xanthomonads Xylella fastidiosa and Stenotrophomonas maltophilia revealed that the hrp, gum, and xcs clusters are recent acquisitions in the Xanthomonas lineage. CONCLUSIONS/SIGNIFICANCE: Our results provide insight into the ancestral Xanthomonas genome and indicate that differentiation with respect to host- and tissue-specificity involved not major

  19. [Equine exudative canker: an (auto-)immune disease?].

    Science.gov (United States)

    Jongbloets, A M C; Sloet van Oldruitenborgh-Oosterbaan, M M; Meeus, P J H M; Back, W

    2005-02-15

    Equine canker is a chronic, hyperplastic, exudative pododermatitis affecting one or more feet. Although many causes and treatments have been suggested, the cause of the disease is still unknown and most probably multifactorial. Local treatments include radical surgical debridement of the diseased hoof tissue and application of caustic substances, antibiotics, and pressure bandaging. Nevertheless, the number of recurrences is high (45%). This article presents a 3-year-old New Forest pony-cross mare in which all horny structures (frogs, coronets, spurs, chestnuts) of all feet were affected. Bacteriological and fungal cultures of the frogs were found negative for the pathogens tested. Papilloma virus was not found. Clinical findings raised the hypothesis that the non-specific hyperplastic inflammation of these horn-like structures might have been caused by an (auto-)immune reaction. On the basis of the clinical findings, the pony was treated with surgical debridement of the frogs of a diagonal pair of feet and oral administration of prednisolone (1 mg/kg sid). The frogs, coronets, spurs, and chestnuts of all four feet healed completely within 8 weeks, thus making an (auto-)immune reaction more likely. In conclusion, this case report raised the hypothesis that an aspecific, hyperplastic inflammation of all four feet ('equine canker') and other horny structures may be caused by an (auto-)immune reaction, and that corticosteroids (prednisolone 1 mg/kg sid per os) are effective as treatment.

  20. Limpeza clonal de mudas de videira infectadas por Xanthomonas campestris pv. viticola Clonal cleaning of grapevine plants infected by Xanthomonas campestris pv. viticola

    Directory of Open Access Journals (Sweden)

    Adriano Márcio Freire Silva

    2013-03-01

    Full Text Available O cancro bacteriano da videira é causado por Xanthomonas campestris pv. viticola (Xcv. Visando à limpeza clonal de mudas de 'Red Globe', foram estudados: tamanho ideal de ápices e gemas axilares para cultivo em meio de Galzy modificado (MGM; efeito da termoterapia (38ºC/30 dias; e ação de antibióticos na eliminação de Xcv em videiras infectadas. Os percentuais de contaminação por Xcv e de regeneração foram analisados, e as plantas obtidas foram indexadas em meio ágar nutritivo-dextrose-extrato de levedura-ampicilina (NYDAM, seguindo-se teste de patogenicidade. O cultivo de explantes com 3 mm possibilitou a obtenção de plantas livres da bactéria, com regeneração 14,3 vezes maior que explantes com 1 mm. A termoterapia de mudas infectadas, associada ao cultivo in vitro, não eliminou o patógeno. O cultivo de explantes com 10 mm, durante 40 dias em MGM + cefotaxima (300 mg L-1, proporcionou limpeza clonal das mudas. A indexação de plantas de videira regeneradas in vitro, quanto à infecção por Xcv utilizando NYDAM, seguida de teste de patogenicidade, é uma alternativa econômica e eficiente para produção de mudas de alta qualidade fitossanitária.Bacterial canker is caused by Xanthomonas campestris pv. viticola (Xcv. In order to eliminate Xcv from 'Red Globe' plants it was studied: optimal size of meristem tips and axillary buds for cultivation in modified Galzy's medium (MGM; effects of thermotherapy (38ºC/30 days; and action of antibiotics in the elimination of Xcv in infected grapevines. The percentages of contamination by Xcv and regeneration were analyzed and plants obtained were indexed using the semi-selective culture medium nutrient agar-dextrose-yeast extract-ampicilin (NYDAM followed by a pathogenicity test. The cultivation of 3 mm explants permitted to obtain plants free of bacteria with regeneration 14.3 times higher than 1 mm explants. The thermotherapy of infected plants associated to the in vitro culture

  1. Discrimination of Five Citrus Diseased Leaves by FTIR Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Xingxiang; ZHAO; Gang; LIU; Weixing; LI; Xiaohua; Wang; Jianming; HAO; Xiangping; ZHOU

    2014-01-01

    In this paper,citrus brown spot,huanglongbing,canker,fuliginous,Cercospora sp. and healthy leaves were studied using Fourier transform infrared spectroscopy( FTIR) combined with statistical analysis. The results showed that the spectra of the samples were similar,whereas there were obvious differences in the second derivatives of infrared spectra in the range of 1 500- 700 cm- 1. The correlative analysis were evaluated,results showed that the correlation coefficients were larger than 0. 918 between healthy leaves,and between the same diseased leaves. However,the values were all decreased between healthy and diseased leaves,and among different diseased leaves. The preprocessed original,first derivative and second derivative spectra in the range of 1 200- 700 cm- 1were chosen to evaluated principal component analysis( PCA) and hierarchical cluster analysis( HCA),respectively. The performance of the overall accuracy of PCA was 92.5%,which were better than original dataset and first derivative dataset. HCA by selecting second derivative dataset yield about 90% accuracy. This study proved that FTIR spectroscopy could be detected citrus diseases quickly and accurately.

  2. Comparative Genomics of Pathogenic and Nonpathogenic Strains of Xanthomonas arboricola Unveil Molecular and Evolutionary Events Linked to Pathoadaptation.

    Science.gov (United States)

    Cesbron, Sophie; Briand, Martial; Essakhi, Salwa; Gironde, Sophie; Boureau, Tristan; Manceau, Charles; Fischer-Le Saux, Marion; Jacques, Marie-Agnès

    2015-01-01

    The bacterial species Xanthomonas arboricola contains plant pathogenic and nonpathogenic strains. It includes the pathogen X. arboricola pv. juglandis, causing the bacterial blight of Juglans regia. The emergence of a new bacterial disease of J. regia in France called vertical oozing canker (VOC) was previously described and the causal agent was identified as a distinct genetic lineage within the pathovar juglandis. Symptoms on walnut leaves and fruits are similar to those of a bacterial blight but VOC includes also cankers on trunk and branches. In this work, we used comparative genomics and physiological tests to detect differences between four X. arboricola strains isolated from walnut tree: strain CFBP 2528 causing walnut blight (WB), strain CFBP 7179 causing VOC and two nonpathogenic strains, CFBP 7634 and CFBP 7651, isolated from healthy walnut buds. Whole genome sequence comparisons revealed that pathogenic strains possess a larger and wider range of mobile genetic elements than nonpathogenic strains. One pathogenic strain, CFBP 7179, possessed a specific integrative and conjugative element (ICE) of 95 kb encoding genes involved in copper resistance, transport and regulation. The type three effector repertoire was larger in pathogenic strains than in nonpathogenic strains. Moreover, CFBP 7634 strain lacked the type three secretion system encoding genes. The flagellar system appeared incomplete and nonfunctional in the pathogenic strain CFBP 2528. Differential sets of chemoreceptor and different repertoires of genes coding adhesins were identified between pathogenic and nonpathogenic strains. Besides these differences, some strain-specific differences were also observed. Altogether, this study provides valuable insights to highlight the mechanisms involved in ecology, environment perception, plant adhesion and interaction, leading to the emergence of new strains in a dynamic environment.

  3. Comparative genomics of pathogenic and nonpathogenic strains of Xanthomonas arboricola unveil molecular and evolutionary events linked to pathoadaptation

    Directory of Open Access Journals (Sweden)

    Sophie eCesbron

    2015-12-01

    Full Text Available The bacterial species Xanthomonas arboricola contains plant pathogenic and nonpathogenic strains. It includes the pathogen X. arboricola pv. juglandis, causing the bacterial blight of Juglans regia. The emergence of a new bacterial disease of Juglans regia in France called vertical oozing canker (VOC was previously described and the causal agent was identified as a distinct genetic lineage within the pathovar juglandis. Symptoms on walnut leaves and fruits are similar to those of a bacterial blight but VOC includes also cankers on trunk and branches. In this work, we used comparative genomics and physiological tests to detect differences between four X. arboricola strains isolated from walnut tree: strain CFBP 2528 causing walnut blight, strain CFBP 7179 causing VOC and two nonpathogenic strains, CFBP 7634 and CFBP 7651, isolated from healthy walnut buds. Whole genome sequence comparisons revealed that pathogenic strains possess a larger and wider range of mobile genetic elements than nonpathogenic strains. One pathogenic strain, CFBP 7179, possessed a specific integrative and conjugative element of 95 kb encoding genes involved in copper resistance, transport and regulation. The type three effector repertoire was larger in pathogenic strains than in nonpathogenic strains. Moreover, CFBP 7634 strain lacked the type three secretion system encoding genes. The flagellar system appeared incomplete and nonfunctional in the pathogenic strain CFBP 2528. Differential sets of chemoreceptor and different repertoires of genes coding adhesins were identified between pathogenic and nonpathogenic strains. Besides these differences, some strain-specific differences were also observed. Altogether, this study provides valuable insights to highlight the mechanisms involved in ecology, environment perception, plant adhesion and interaction, leading to the emergence of new strains in a dynamic environment.

  4. Soil and Stocking Effects on Caliciopsis Canker of Pinus strobus L.

    Directory of Open Access Journals (Sweden)

    Isabel A Munck

    2016-11-01

    Full Text Available Soil and stand density were found to be promising predictive variables associated with damage by the emerging disease of eastern white pine, Caliciopsis canker, in a 2014 survey with randomly selected eastern white pine (Pinus strobus L. stands. The objective of this study was to further investigate the relationship between soil and stocking in eastern white pine forests of New England by stratifying sampling across soils and measuring stand density more systematically. A total of 62 eastern white pine stands were sampled during 2015–2016. Stands were stratified across soil groups and several prism plots were established at each site to measure stand density and determine stocking. Caliciopsis canker incidence in mature trees was greater in sites with drier or shallow soils compared to sites with loamy soils and in adequately stocked stands compared to understocked stands (p < 0.0001. Caliciopsis canker signs and symptoms were observed in all size classes. Live crown ratio, a measure of forest health, decreased with increasing Caliciopsis canker symptom severity. The fungal pathogen, Caliciopsis pinea Peck, was successfully isolated from cankers on trees growing in each soil group. Forest managers will need to consider damage caused by Caliciopsis canker related to stand factors such as soil and stocking when regenerating white pine stands.

  5. Waardplantonderzoek Prunus laurocerasus voor Xanthomonas : Consultancy-onderzoek

    NARCIS (Netherlands)

    Kuik, van A.J.; Hollinger, T.C.

    2010-01-01

    In de teelt van Prunus laurocerasus komt de laatste jaren een nieuwe ziekte voor, veroorzaakt door de Q-bacterie Xanthomonas aboricola pv pruni (Xap). r Op 9 oktober 2009 is een door de NBvB georganiseerde Xanthomonas-bijeenkomst geweest. Gezien de ernst van de situatie voor de boomkwekerijsector is

  6. Natural occurrence and pathogenicity of Xanthomonas bacteria on ...

    African Journals Online (AJOL)

    Tuoyo Aghomotsegin

    The bacterial genus Xanthomonas consists of several species of economic importance, among which. Xanthomonas ... of economic importance as they affect the production of different crops ..... significantly greater than for the others. As a result, ..... NW (ed) Laboratory guide for identification of plant pathogenic bacteria, 2nd ...

  7. PHARMACOLOGICAL IMPORTANCE OF CITRUS FRUITS

    Directory of Open Access Journals (Sweden)

    Amita Tomar *, Mridula Mall and Pragya Rai

    2013-01-01

    Full Text Available This paper reviews the pharmacological importance of citrus fruits. Citrus fruits are used for various pharmacological importance. According to literature the citrus fruit possess anti-cancer, antimicrobial, antioxidant, antiulcer, anti-inflammatory, and hypolipidemic and hepatoprotective properties.

  8. Strategic planning for the Florida citrus industry: addressing citrus greening disease

    National Research Council Canada - National Science Library

    2010-01-01

    "Citrus greening, a disease that reduces yield, compromises the flavor, color, and size of citrus fruit and eventually kills the citrus tree, is now present in all 34 Floridian citrus-producing counties...

  9. Antioxidant activity of Citrus fruits.

    Science.gov (United States)

    Zou, Zhuo; Xi, Wanpeng; Hu, Yan; Nie, Chao; Zhou, Zhiqin

    2016-04-01

    Citrus is well-known for its nutrition and health-promotion values. This reputation is derived from the studies on the biological functions of phytochemicals in Citrus fruits and their derived products in the past decades. In recent years, the antioxidant activity of Citrus fruits and their roles in the prevention and treatment of various human chronic and degenerative diseases have attracted more and more attention. Citrus fruits are suggested to be a good source of dietary antioxidants. To have a better understanding of the mechanism underlying the antioxidant activity of Citrus fruits, we reviewed a study on the antioxidant activity of the phytochemicals in Citrus fruits, introduced methods for antioxidant activity evaluation, discussed the factors which influence the antioxidant activity of Citrus fruits, and summarized the underlying mechanism of action. Some suggestions for future study were also presented.

  10. Oak Tree Canker Disease Supports Arthropod Diversity in a Natural Ecosystem

    Directory of Open Access Journals (Sweden)

    Yong-Bok Lee

    2014-03-01

    Full Text Available Microorganisms have many roles in nature. They may act as decomposers that obtain nutrients from dead materials, while some are pathogens that cause diseases in animals, insects, and plants. Some are symbionts that enhance plant growth, such as arbuscular mycorrhizae and nitrogen fixation bacteria. However, roles of plant pathogens and diseases in natural ecosystems are still poorly understood. Thus, the current study addressed this deficiency by investigating possible roles of plant diseases in natural ecosystems, particularly, their positive effects on arthropod diversity. In this study, the model system was the oak tree (Quercus spp. and the canker disease caused by Annulohypoxylon truncatum, and its effects on arthropod diversity. The oak tree site contained 44 oak trees; 31 had canker disease symptoms while 13 were disease-free. A total of 370 individual arthropods were detected at the site during the survey period. The arthropods belonged to 25 species, 17 families, and seven orders. Interestingly, the cankered trees had significantly higher biodiversity and richness compared with the canker-free trees. This study clearly demonstrated that arthropod diversity was supported by the oak tree canker disease.

  11. Xanthan production by Xanthomonas albilineans infecting sugarcane stalks.

    Science.gov (United States)

    Blanch, María; Legaz, María-Estrella; Vicente, Carlos

    2008-03-13

    Xanthomonas albilineans is the causal organism of leaf scald, a bacterial vascular disease of sugarcane. Xanthomonas may invade the parenchyma between the bundles and cause reddened pockets of gum, identified as a xanthan-like polysaccharide. Since xanthan contains glucuronic acid, the ability of Xanthomonas to produce an active UDP glucose dehydrogenase is often seen as a virulence factor. X. albilineans axenically cultured did not secrete xanthans to Willbrink liquid media, but the use of inoculated sugarcane tissues for producing and characterizing xanthans has been required. A hypothesis about the role of sugarcane polysaccharides to assure the production of bacterial xanthan is discussed.

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

    Science.gov (United States)

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

    2002-10-01

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

  13. A method for estimating white pine blister rust canker age on limber pine in the central Rocky Mountains

    Science.gov (United States)

    Holly S. J. Kearns; William R. Jacobi; Brian W. Geils

    2009-01-01

    Epidemiological studies of white pine blister rust on limber pine require a temporal component to explain variations in incidence of infection and mortality. Unfortunately, it is not known how long the pathogen has been present at various sites in the central Rocky Mountains of North America. Canker age, computed from canker length and average expansion rate, can be...

  14. Bacterial canker of plum caused by Pseudomonas syringae pathovars, as a serious threat for plum production in the Netherlands

    NARCIS (Netherlands)

    Wenneker, M.; Janse, J.D.; Bruine, de A.; Vink, P.; Pham, K.T.K.

    2012-01-01

    In the Netherlands, bacterial canker of plum trees (Prunus domestica) caused by Pseudomonas syringae pathovars syringae and morsprunorum is a recent and serious problem. The trunks of the affected plum trees are girdled by cankers resulting in relatively sudden death of the trees 1 to 4 years after

  15. Bacterial canker of plum caused by Pseudomonas syringae pathovars, as a serious threat for plum production in the Netherlands

    NARCIS (Netherlands)

    Wenneker, M.; Janse, J.D.; Bruine, de A.; Vink, P.; Pham, K.T.K.

    2012-01-01

    In the Netherlands, bacterial canker of plum trees (Prunus domestica) caused by Pseudomonas syringae pathovars syringae and morsprunorum is a recent and serious problem. The trunks of the affected plum trees are girdled by cankers resulting in relatively sudden death of the trees 1 to 4 years after

  16. Cercosporoid diseases of Citrus

    NARCIS (Netherlands)

    Huang, Feng; Groenewald, J.Z.; Zhu, Li; Crous, P.W.; Li, Hongye

    2015-01-01

    Citrus leaves and fruits exhibiting disease symptoms ranging from greasy spot, yellow spot, small or large brown spot, black dot, and brown dot were sampled from Fujian, Guangdong, Guizhou, Hunan, Jiangxi, Yunnan, Zhejiang provinces and the Guangxi Zhuang Autonomous Region in China. In total 82 isol

  17. Potential Nutritional Benefits of Current Citrus Consumption

    Directory of Open Access Journals (Sweden)

    Tami Turner

    2013-03-01

    Full Text Available Citrus contains nutrients and phytochemicals that may be beneficial for health. We collected citrus production and consumption data and estimated the amount of these compounds that are consumed. We then compared the amounts of citrus and citrus-derived compounds used in studies that suggest a health benefit to the amounts typically found in citrus. Data is scarce, but suggests that citrus consumption might improve indices of antioxidant status, and possibly cardiovascular health and insulin sensitivity.

  18. 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)

  19. 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.

  20. Phytophthora species associated with stem cankers on tanoak in southwestern Oregon

    Science.gov (United States)

    Paul Reeser; Wendy Sutton; Everett Hansen

    2008-01-01

    In effort to eradicate Phytophthora ramorum from Oregon forests, tanoak over its entire range in southwestern Oregon is surveyed intensively for stem disease. Pieces of bark from the leading edge of tanoak stem cankers were plated on cornmeal agar amended with 10 ppm natamycin, 200 ppm a-ampicillin, and 10 ppm rifamycin SV (CARP) to favor the...

  1. Cold-Induced Cankers and Associated Fungi in a Sycamore Seed Orchard

    Science.gov (United States)

    Francis I. McCracken; R. Rousseau

    1991-01-01

    Of the trees in a 6-year-old sycamore seed orchard in Carlisle County, KY, 66 percent developed obscure vertical cankers in the spring of 1990. A variety of wound-invading saprophytes, including Hyalodendron sp., Stachylidium sp., Botrytis sp., Phialophora sp., Trichoderma...

  2. Bacterial Canker (Clavibacter michiganensis subsp. michiganensis) of tomato in commercial seed produced in Indonesia

    NARCIS (Netherlands)

    Anwar, A.; Zouwen, van der P.S.; Ilyas, S.; Wolf, van der J.M.

    2004-01-01

    In 2002, Clavibacter michiganensis subsp. michiganensis (Smith) Davis, the causal organism of bacterial canker of tomato (Lycopersicon esculentum), was isolated from two of six commercial asymptomatic tomato seed lots produced on Java in Indonesia. C. michiganensis subsp. michiganensis has not been

  3. Bacterial Canker of Tomato: Current Knowledge of Detection, Management, Resistance, and Interactions

    NARCIS (Netherlands)

    Sen, Y.; Wolf, van der J.M.; Visser, R.G.F.; Heusden, van A.W.

    2015-01-01

    Clavibacter michiganensis subsp. michiganensis is the causal agent of bacterial canker of tomato. The disease was first described in 1910 in Michigan, USA. C. michiganensis subsp. michiganensis (from now on called clavibacter) was initially thought to be a phloem parasite, but was later found to be

  4. First report of Phaeobotryon cupressi causing canker of Calocedrus decurrens in Oregon.

    Science.gov (United States)

    Since the early 2000’s a canker disease has been noticed with increasing frequency on landscape specimens of native incense cedar (Calocedrus decurrens) planted throughout the Willamette Valley (from Portland south to Eugene) in western Oregon. Symptoms initially appear as dead and flagging small-di...

  5. New canker disease of Incense-cedar in Oregon caused by Phaeobotryon cupressi.

    Science.gov (United States)

    Incense-cedar (Calocedrus decurrens) is a native tree occurring in Oregon and California. Since the early 2000’s, a new canker disease has been observed with increasing frequency on ornamental and windbreak trees planted in the Willamette Valley of Oregon. Symptoms appear as dead, flagging, small-di...

  6. Prevalence, distribution and identification of Phytophthora species from bleeding canker on European beech

    Science.gov (United States)

    While bleeding canker of European beech (Fagus sylvatica) has long been recognized as a problem, the cause in the northeastern United States has not been clear. To resolve this, we surveyed for disease prevalence, identified the pathogens involved, proved their pathogenicity, compared protocols for ...

  7. Approaches for evaluation of resistance to European canker (Neonectria ditissima) in apple

    NARCIS (Netherlands)

    Garkava-Gustavsson, L.; Ghasemkhani, M.; Zborowska, A.; Englund, J.E.; Lateur, M.; Weg, van de E.

    2016-01-01

    European canker is caused by the fungus Neonectria ditissima (Neonectria galligena, formerly Nectria galligena). The disease causes significant losses to apple production in Sweden and many other countries with a temperate wet climate. Application of fungicides and good horticultural practices do

  8. Phomopsis Stem Canker: A Reemerging Threat to Sunflower (Helianthus annuus) in the United States.

    Science.gov (United States)

    Mathew, Febina M; Alananbeh, Kholoud M; Jordahl, James G; Meyer, Scott M; Castlebury, Lisa A; Gulya, Thomas J; Markell, Samuel G

    2015-07-01

    Phomopsis stem canker causes yield reductions on sunflower (Helianthus annuus L.) on several continents, including Australia, Europe, and North America. In the United States, Phomopsis stem canker incidence has increased 16-fold in the Northern Great Plains between 2001 and 2012. Although Diaporthe helianthi was assumed to be the sole causal agent in the United States, a newly described species, D. gulyae, was found to be the primary cause of Phomopsis stem canker in Australia. To determine the identity of Diaporthe spp. causing Phomopsis stem canker in the Northern Great Plains, 275 infected stems were collected between 2010 and 2012. Phylogenetic analyses of sequences of the ribosomal DNA internal transcribed spacer region, elongation factor subunit 1-α, and actin gene regions of representative isolates, in comparison with those of type specimens, confirmed two species (D. helianthi and D. gulyae) in the United States. Differences in aggressiveness between the two species were determined using the stem-wound method in the greenhouse; overall, D. helianthi and D. gulyae did not vary significantly (P≤0.05) in their aggressiveness at 10 and 14 days after inoculation. These findings indicate that both Diaporthe spp. have emerged as sunflower pathogens in the United States, and have implications on the management of this disease.

  9. The potential for citrus cryotherapy

    Science.gov (United States)

    Citrus collections of pathogen-free plants are needed for breeding, research, and distribution to the user community. The Citrus Research Board funded research project “Development of cryotherapy as an improved method of eliminating graft transmissible pathogens in Citrus” sought to use cryotherapy,...

  10. 76 FR 8603 - Citrus Seed Imports; Citrus Greening and Citrus Variegated Chlorosis

    Science.gov (United States)

    2011-02-15

    ... propagative seed of several Rutaceae (citrus family) genera from certain countries where citrus greening or... Rutaceae may be a pathway for the introduction of those diseases. The interim rule was necessary in order...), we amended the regulations to prohibit the importation of propagative seed of several...

  11. Development of resistant tomato population with bacterial canker resistance genes from interspecific hybrids by the support of embryo rescue

    OpenAIRE

    Aylin KABAŞ; Esin ARI; Sinan ZENGİN; Hülya İLBİ; AYSAN, Yeşim; Asu OĞUZ

    2016-01-01

    Bacterial canker is one of the most important diseases causing economic yield loss in tomato production areas in the world. The best way to control for this disease is to use resistant varieties. However, there are few studies on variety breeding studies of this disease compared with other disease resistant breeding studies. In this study we aimed to improve inbred lines carrying bacterial canker resistance genes to use in the breeding of resistant varieties. Susceptible inbred line AK1 (S. e...

  12. The Citrus Sanitation Center of Estación Experimental Agroindustrial Obispo Colombres, Tucumán, Argentina El Centro de Saneamiento de Citrus de la Estación Experimental Agroindustrial Obispo Colombres de Tucumán, Argentina

    Directory of Open Access Journals (Sweden)

    Beatriz E. Stein

    Full Text Available In October 2004, the Estación Experimental Agroindustrial Obispo Colombres (Tucumán, Argentina founded its Citrus Sanitation Center. The goal of this center is to establish and keep a group of the most important citrus varieties and rootstocks true to type and free of graft-transmissible pathogens. These will be used as primary sources of propagating material for citrus growers and researchers in northwestern Argentina. Mother trees of the main commercial citrus varieties were selected from the germplasm bank of the experiment station and were recovered through the standard procedure of shoot tip grafting (STG. Healthy plants are carefully and periodically indexed by biological, serological and molecular methods for tristeza, psorosis, exocortis, cachexia, citrus variegated chlorosis, citrus canker and huanglongbing. The Citrus Sanitation Center will maintain a supply of healthy propagation material and will continue a program initiated in 1966, consting in introducing, producing and releasing nucellar clones.La Estación Experimental Agroindustrial Obispo Colombres (EEAOC creó en el año 2004 el Centro de Saneamiento de Citrus (CSC para la ejecución de tareas de limpieza y diagnóstico de virus en cítricos. El objetivo de este centro es establecer y mantener un plantel de plantas madres cítricas, de variedades copa y portainjertos, de alta calidad genética y libre de plagas y enfermedades transmisibles por injerto. Este grupo de plantas se constituye como fuente primaria de material de propagación para productores, viveristas e investigadores del noroeste argentino. Las plantas madres de las principales variedades comerciales de cítricos se seleccionaron del banco de germoplasma de la EEAOC y se recuperaron por la técnica de microinjerto de ápices caulinares, procedimiento estándar utilizado en la limpieza de plantas cítricas. Periódicamente se verifica su sanidad por métodos biológicos, serológicos y moleculares para las

  13. Occurrence of Clavibacter michiganensis subsp. michiganensis, the causal agent of bacterial canker of tomato, in Syria

    Directory of Open Access Journals (Sweden)

    Radwan FTAYEH

    2010-09-01

    Full Text Available Several surveys were carried out to evaluate the occurrence of bacterial canker of tomato caused by Clavibacter michiganensis subsp. michiganensis (Cmm in Syria, especially in the North-West provinces Latakiaand Tartous. The surveys revealed typical disease symptoms in greenhouses where the tomato cvs. Dima, Huda and Astona were grown, such as dark brown to black lesions on the leaf margins, wilting of whole plants, stunting, and vascular discoloration. The disease incidence in such greenhouses was 15% in the spring of 2007, and up to 70% by the end of July. Ten isolates obtained from diseased plants at different locations in these two provinces were identified as Clavibacter michiganensis subsp. michiganensis using classical microbiological tests as well as PCR. This is the first detailed proof of the occurrence of bacterial canker of tomato in Syria.

  14. First Report and Characterization of Pestalotiopsis ellipsospora Causing Canker on Acanthopanax divaricatus.

    Science.gov (United States)

    Yun, Yeo Hong; Ahn, Geum Ran; Kim, Seong Hwan

    2015-09-01

    Acanthopanax divaricatus, a member of the Araliaceae family, has been used as an invigorant in traditional Korean medicine. During disease monitoring, a stem with small, irregular, brown lesions was sampled at a farm in Cheonan in 2011. The symptoms seen were sunken cankers and reddish-brown needles on the infected twig. The isolated fungal colonies were whitish, having crenated edges and aerial mycelium on the surface, and with black gregarious fruiting bodies. The reverse plate was creamy white. Conidia were 17~22 × 3.5~4.2 µm, fusiform, 4-septate, and straight to slightly curved. The nucleotide sequence of the partial translation elongation factor 1 alpha gene of the fungal isolate, shares 99% sequence identity with that of known Pestalotiopsis ellipsospora. Based on the results of the morphological and molecular analyses, the fungal isolate was identified as P. ellipsospora. In Korea, this is the first report of canker on A. divaricatus.

  15. Scientific Opinion on a technical file submitted by the Japanese Authorities to support a derogation request from the EU import requirements for bonsai and topiary trees that are host plants of Anoplophora chinensis

    DEFF Research Database (Denmark)

    Baker, R.; Candresse, T.; Dormannsné Simon, E.

    2010-01-01

    Following a request from the EU Commission, the EFSA PLH Panel conducted a scientific opinion on risk analysis and supporting documents provided by APHIS/USDA in support of the request to remove the Union's plant health import requirement that citrus fruit imported into the EU be sourced from...... groves where, since the beginning of the last cycle of vegetation no symptoms of citrus canker were observed, neither in their vicinities. The PHL Panel concluded that the transmission of Xanthomonas citri subsp. citri (Xcc) on asymptomatic citrus fruit was more likely when the fruit were collected from...

  16. Soil and Stocking Effects on Caliciopsis Canker of Pinus strobus L.

    OpenAIRE

    Isabel A. Munck; Thomas Luther; Stephen Wyka; Donald Keirstead; Kimberly McCracken; William Ostrofsky; Wayne Searles; Kyle Lombard; Jennifer Weimer; Bruce Allen

    2016-01-01

    Soil and stand density were found to be promising predictive variables associated with damage by the emerging disease of eastern white pine, Caliciopsis canker, in a 2014 survey with randomly selected eastern white pine (Pinus strobus L.) stands. The objective of this study was to further investigate the relationship between soil and stocking in eastern white pine forests of New England by stratifying sampling across soils and measuring stand density more systematically. A total of 62 eastern...

  17. Clavibacter michiganensis subsp. capsici subsp. nov., causing bacterial canker disease in pepper.

    Science.gov (United States)

    Oh, Eom-Ji; Bae, Chungyun; Lee, Han-Beoyl; Hwang, In Sun; Lee, Hyok-In; Yea, Mi Chi; Yim, Kyu-Ock; Lee, Seungdon; Heu, Sunggi; Cha, Jae-Soon; Oh, Chang-Sik

    2016-10-01

    Clavibacter michiganensis is a Gram-stain-positive bacterium with eight subspecies. One of these subspecies is C. michiganensis subsp. michiganensis, which causes bacterial canker disease in tomato. Bacterial strains showing very similar canker disease symptoms to those of a strain originally classified as C. michiganensis have been isolated from pepper. In this paper, we reclassified strains isolated from pepper. On the basis of phylogenetic analysis with 16S rRNA gene sequences, the strains isolated from pepper were grouped in a separate clade from other subspecies of C. michiganensis. Biochemical, physiological and genetic characteristics of strain PF008T, which is the representative strain of the isolates from pepper, were examined in this study. Based on multi-locus sequence typing and other biochemical and physiological features including colony color, utilization of carbon sources and enzyme activities, strain PF008T was categorically differentiated from eight subspecies of C. michiganensis. Moreover, genome analysis showed that the DNA G+C content of strain PF008T is 73.2 %. These results indicate that PF008T is distinct from other known subspecies of C. michiganensis. Therefore, we propose a novel subspecies, C. michiganensis subsp. capsici, causing bacterial canker disease in pepper, with a type strain of PF008T (=KACC 18448T=LMG 29047T).

  18. Physiological effect of the toxin from Xanthomonas retroflexus on ...

    African Journals Online (AJOL)

    user

    A new toxin from Xanthomonas retroflexus could cause a series of physiological responses on seedlings of ... protein, cell division and ultrastructure of the leaf. ... 28°C in bacterial medium (beef extract 5.0 g, peptone 10.0 g, NaCl. 15.0 g ...

  19. Evaluation of Antibacterial Activities of Citrus limon, Citrus reticulata, and Citrus grandis Against Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Sholeh Saeb

    2016-11-01

    Full Text Available Background: Microorganisms resistant to most antibiotics are rapidly spreading, and there is an urgent and continuous need for novel antimicrobial compounds. The genus Citrus belongs to the family Rutaceae has many biologically active secondary metabolites. Objectives: The purpose of this study was to evaluate antimicrobial activity of essential oil and extract of Lemon (Citrus limon, Mandarin (Citrus reticulata and Pummelo (Citrus grandis against Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Salmonella typhi. Materials and Methods: The fresh Citrus leaves were shade-dried and powdered. Antimicrobial metabolites were extracted from them by 80% methanol for extract and using a Clevenger-type apparatus for essential oil. Eight different concentrations of the each leaf extract and essential oil were prepared. The antimicrobial susceptibility assay of Citrus leaves metabolites were subjected against four bacterial strains by agar disc diffusion and E-test method. Results: In this study, minimum inhibitory concentrations (MIC of different Citrus leaf extracts were determined against all four food-borne pathogens. The C. grandis leaf essential oil had potent antimicrobial activity against all four pathogens, and the C. limon leaf essential oil was effective on Gram-positive bacteria. S. typhi was resistant against two leaves essential oils. Conclusions: The results showed that there was no antimicrobial activity effect in all extracts on tested bacteria. In this study, the antibacterial effect of essential oil of Citrus leaves on four strains of pathogenic microorganisms was confirmed. The C. grandis leaf essential oil had the most powerful antimicrobial properties, suggesting its potential application as natural preservative in foods or an effective medicine against different pathogenic microbes. Key words: Antibacterial activity, E-test, Citr

  20. Control of virus diseases of citrus.

    Science.gov (United States)

    Lee, Richard F

    2015-01-01

    Citrus is thought to have originated in Southeast Asia and horticulturally desirable clonal selections have been clonally cultivated for hundreds of years. While some citrus species have nucellar embryony, most cultivation of citrus has been by clonal propagation to ensure that propagated plants have the same traits as the parent selection. Clonal propagation also avoids juvenility, and the propagated plants produce fruit sooner. Because of the clonal propagation of citrus, citrus has accumulated a large number of viruses; many of these viruses are asymptomatic until a susceptible rootstock and/or scion is encountered. The viruses reported to occur in citrus will be summarized in this review. Methods of therapy to clean selected clones from viruses will be reviewed; the use of quarantine, clean stock, and certification programs for control of citrus viruses and other strategies to control insect spread citrus viruses, such as mild strain cross-protection and the use of pest management areas will be discussed.

  1. Full Genome Sequence Analysis of Two Isolates Reveals a Novel Xanthomonas Species Close to the Sugarcane Pathogen Xanthomonas albilineans

    Directory of Open Access Journals (Sweden)

    Isabelle Pieretti

    2015-07-01

    Full Text Available Xanthomonas albilineans is the bacterium responsible for leaf scald, a lethal disease of sugarcane. Within the Xanthomonas genus, X. albilineans exhibits distinctive genomic characteristics including the presence of significant genome erosion, a non-ribosomal peptide synthesis (NRPS locus involved in albicidin biosynthesis, and a type 3 secretion system (T3SS of the Salmonella pathogenicity island-1 (SPI-1 family. We sequenced two X. albilineans-like strains isolated from unusual environments, i.e., from dew droplets on sugarcane leaves and from the wild grass Paspalum dilatatum, and compared these genomes sequences with those of two strains of X. albilineans and three of Xanthomonas sacchari. Average nucleotide identity (ANI and multi-locus sequence analysis (MLSA showed that both X. albilineans-like strains belong to a new species close to X. albilineans that we have named “Xanthomonas pseudalbilineans”. X. albilineans and “X. pseudalbilineans” share many genomic features including (i the lack of genes encoding a hypersensitive response and pathogenicity type 3 secretion system (Hrp-T3SS, and (ii genome erosion that probably occurred in a common progenitor of both species. Our comparative analyses also revealed specific genomic features that may help X. albilineans interact with sugarcane, e.g., a PglA endoglucanase, three TonB-dependent transporters and a glycogen metabolism gene cluster. Other specific genomic features found in the “X. pseudalbilineans” genome may contribute to its fitness and specific ecological niche.

  2. Survey for Citrus diseases in French Guiana

    OpenAIRE

    Thermoz, Jean-Pierre

    2007-01-01

    The presence on the continent of major threats for Citrus orchards has required a survey to assess the situation of Citrus pathogens in the French territory of Guiana. Agriculture in French Guiana is located on the coast (about 300 Kms from west to east and 50 Km wide). There are 1200 Ha of Citrus orchards (Ministry of Agriculture). Citrus are grown either for export (Tahiti lime) or for local consumption : sweet oranges, tangerines and hybrids. Trees are grafted on Carrizo citrange, Rough le...

  3. Citrus Limonoids: Analysis, Bioactivity, and Biomedical Prospects

    Science.gov (United States)

    This publication is a review of the chemistry, biochemistry and bioactivity of limonoids occurring in citrus. The review chronologically relates the evolution of research in citrus limonoids beginning with their association with bitterness development in citrus juices. The chemical and biochemical...

  4. Soil Micronutrients and Citrus Growth

    Institute of Scientific and Technical Information of China (English)

    OUYANGTAO

    1993-01-01

    By using nutritional diagnosis of citrus leaves and determining soil micronutrients,the relationship between soil micronutrients and citrus growth in southern China has been studied.Studies showed that there was a significant positive correlation between available micronutrients (such as Zn,Mo,Cu)in the soil and the corresponding nutrients in citrus leaves.Thus,one can roughly learn of the sufficiency or deficiency of certain nutrients in soils by analyzing citrus leaves.Rational spray of Zn B or Mo fertilizer not only improved citrus yields but also increased the total sugar of Satsuma mandarin and of Xinhui orange by 2.9 and 17.2% respectively compared with the control.Spraying Mo fertilizer increased the vitamin C content of Satsuma mandarin juice by 4.7%-8.4%,maturated fruits 7-10 days earlier and gave the peel a brighter color.The ultramicroscopic characteristics of Zn-deficient citrus leaves were investigated under an electron microscope.Results showed that the Zn-deficient leaf cell was characterized mainly by poor cytoplasm,endoplasmic reticula and ribosomes and by big starch grains in the chloroplast.As a result of spraying Zn fertilizer the structure of the cell returned to normal,the cytoplasm became rich and the amount of chloroplast increased.There also appeared a great deal of multiform endoplasmic reticula,thus promoting the photosynthesis of Zn-deficient plants.This provides a cytologico-theoretical basis for fertilization of high-yielding citrus trees.

  5. 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)

  6. Draft whole-genome sequence of the Diaporthe helianthi 7/96 strain, causal agent of sunflower stem canker

    Directory of Open Access Journals (Sweden)

    Riccardo Baroncelli

    2016-12-01

    Full Text Available Diaporthe helianthi is a fungus pathogenic to sunflower. Virulent strains of this fungus cause stem canker with important yield losses and reduction of oil content. Here we present the first draft whole-genome sequence of the highly virulent isolate D. helianthi strain 7/96, thus providing a useful platform for future research on stem canker of sunflower and fungal genomics. The genome sequence of the D. helianthi isolate 7/96 was deposited at DDBJ/ENA/GenBank under the accession number MAVT00000000 (BioProject PRJNA327798.

  7. Assessment of genetic diversity of Xanthomonas oryzae pv. oryzae

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@Bacterial blight of rice, caused by Xanthomonas oryzae pv. Oryzae(Xoo. ), is one of the major rice diseases in China. Making clear the shift of genetic diversity of the pathogen will provide important information for rice breeding. Strains collected from 11 provinces located in Southern region of the Changjiang River in China were assessed by using inoculation method and IS-PCR(Insertion Sequence-Based Polymerase Chain Reaction) analysis.

  8. Antagonism of Bacillus spp. against Xanthomonas campestris pv. campestris

    OpenAIRE

    Leila Monteiro; Rosa de Lima Ramos Mariano; Ana Maria Souto-Maior

    2005-01-01

    The antagonism of eight Bacillus isolates was investigated against nine strains of Xanthomonas campestris pv. campestris (causal agent of crucifers black rot) to assess the role of lipopeptides in this process. Antimicrobial and hemolytic (surfactant) activity tests were performed in vitro using agar diffusion methods. Antibiosis and hemolysis were positive for four Bacillus isolates against all X. campestris pv. campestris strains. The correlation observed between antimicrobial and hemolytic...

  9. Effectivity of Kaffir lime (Citrus hystrix, Nasnaran Mandarin (Citrus amblycarpa, and Pomelo (Citrus maxima Leaf Extract Against Aedes aegypti Larvae

    Directory of Open Access Journals (Sweden)

    Hebert Adrianto

    2014-03-01

    Full Text Available The used of chemicals as larvicidal may causing resistance, health problem, and environment problem. Leaf extracts of Citrus as biolarvicidal against Aedes aegypti larvae can be used as an alternative larvicidal. The aims of this study is to find out the species of Citrus in the study sample, which is the most effective as biolarvicidal. This study was conducted using nested experiment design, with six treatments and five replicates. Larvae mortality was observed after 24 and 48 hours. Then, data were analyzed by probit. The results of this study show that (1 the LC95 value after 24 hours of exposure of leaf extracts of Citrus hystrix, Citrus amblycarpa, and Citrus maxima, were each 3,176 ppm; 4,174 ppm; and 6,369 ppm. (2 the LC95 value after 48 hours of exposure of leaf extracts of Citrus hystrix, Citrus amblycarpa, and Citrus maxima, were each 2,499 ppm; 3,256 ppm; and 4,886 ppm. (3 leaf extract of Citrus hystrix is the most effective among others as biolarvicidal against Aedes aegypti larvae. Leaf extract of Citrus hystrix can be used as alternative biolarvicidal.

  10. Characterization of two coexisting pathogen populations of Leptosphaeria spp., the cause of stem canker of brassicas

    Directory of Open Access Journals (Sweden)

    Joanna Kaczmarek

    2012-12-01

    Full Text Available Stem canker of brassicas, also known as blackleg is the most damaging disease of many Brassicaceae. The disease is caused by Leptosphaeria maculans (Desm. Ces et de Not. and L. biglobosa sp. nov., Shoemaker & Brun, which coexist in plants and resulting in disease symptoms and decreased yield, quantity and quality of cultivated vegetables and oilseed rape. The paper presents taxonomic relationships between these coexisting pathogen species, describes particular stages of their life cycles, summarizes the differences between the species, and reviews methods for their identification.

  11. Molecular characterisation of Xanthomonas strains isolated from aroids in Mauritius.

    Science.gov (United States)

    Khoodoo, M H R; Sahin, F; Donmez, M F; Fakim, Y Jaufeerally

    2005-06-01

    Mauritius is one of the largest world producers of Anthurium cut flowers but outbreaks of bacterial blight have never been reported on the island. This work was about the characterisation and identification of bacterial strains isolated from Anthurium andreanum, Dieffenbachia maculata and Aglaonema simplex in Mauritius. Fifteen strains, that showed the morphological properties of Xanthomonas on conventional media, were tested on two semi-selective media (Esculin-trehalose and cellobiose-starch). ELISA tests using a panel of monoclonal antibodies were carried out and three out of 15 strains reacted with a Xanthomonas-specific monoclonal antibody (MAb XII). Analysis using four sets of ribosomal primers revealed that the same three Mauritius strains shared conserved PCR products with reference xanthomonads including virulent strains of Xanthomonas axonopodis pv. dieffenbachiae (Xad). BIOLOG tests and the Sherlock Microbial Identification system (MIDI) identified these three new strains at the species level as X. axonopodis. The complementary tests that were carried out clearly confirmed that the three strains are xanthomonads and, moreover, a DNA probe which showed specificity to Xad strains suggested that the three Mauritius strains are non-virulent forms of the pathogen causing Anthurium blight.

  12. 'Wuzishatangju' mandarin (Citrus reticulata Blanco)

    African Journals Online (AJOL)

    ARL4

    African Journal of Biotechnology Vol. 11(89), pp. ... increased to meet the challenge of process industry and particular consumer ... biotechnology, the advent of molecular markers has made it ..... Innovation and Utilization for Germplasm Resources in ... Construction of DNA fingerprinting database of citrus cultivars. (Lines).

  13. Isolation and Characterization of Bacteriophages Against Pseudomonas syringae pv. actinidiae Causing Bacterial Canker Disease in Kiwifruit.

    Science.gov (United States)

    Yu, Ji-Gang; Lim, Jeong-A; Song, Yu-Rim; Heu, Sunggi; Kim, Gyoung Hee; Koh, Young Jin; Oh, Chang-Sik

    2016-02-01

    Pseudomonas syringae pv. actinidiae causes bacterial canker disease in kiwifruit. Owing to the prohibition of agricultural antibiotic use in major kiwifruit-cultivating countries, alternative methods need to be developed to manage this disease. Bacteriophages are viruses that specifically infect target bacteria and have recently been reconsidered as potential biological control agents for bacterial pathogens owing to their specificity in terms of host range. In this study, we isolated bacteriophages against P. syringae pv. actinidiae from soils collected from kiwifruit orchards in Korea and selected seven bacteriophages for further characterization based on restriction enzyme digestion patterns of genomic DNA. Among the studied bacteriophages, two belong to the Myoviridae family and three belong to the Podoviridae family, based on morphology observed by transmission electron microscopy. The host range of the selected bacteriophages was confirmed using 18 strains of P. syringae pv. actinidiae, including the Psa2 and Psa3 groups, and some were also effective against other P. syringae pathovars. Lytic activity of the selected bacteriophages was sustained in vitro until 80 h, and their activity remained stable up to 50°C, at pH 11, and under UV-B light. These results indicate that the isolated bacteriophages are specific to P. syringae species and are resistant to various environmental factors, implying their potential use in control of bacterial canker disease in kiwifruits.

  14. Key factors for causing poplar Ice Nucleation Active bacterial canker and its control techniques

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The isolation, culture and the active determination of poplar ice nucleation active (INA) bacteria and the inoculation tests in laboratory and field were conducted, and the varieties, distribution and number of poplar INA bacteria and its pathogenicity and freezing injury property were determined. The study results showed that the INA bacteria widely spread on poplar in Northeast China and caused the frozen injury for poplar under the frost condition in Spring or Autumn, which was the key factor to induce INA bacterial canker. Through evaluation and investigation of different poplar varieties and inoculation tests, fine disease-resistant varieties and strains of poplar suitable for Northeast China were selected. Further tests for strong seedling showed that burying cuttings in sand and covering with plastic film could effectively avoid the frostbite, frozen and drought damage, reduce INA bacteria infection, and promote poplar growth. INA bacterial canker was detected early by highly specialized antiserums of INA bacteria and the agglutinated test of ring-shaped boundary surface. The inducers such as streptomycin, phenylmercuric acetae, salicylic acid and heat-killed bacteria to immerse cuttings, have obvious induced disease-resistant effect. Before poplar sprouted in early spring, through spraying the solution of frostbite agent, the control effect also was obvious.

  15. Field ID guide to citrus relative hosts of Asian citrus psyllid & Huanglongbing

    Science.gov (United States)

    The Rutaceae family of plants includes not only species within the genus Citrus, but also several other genera and species that may not be easily recognized as having any relationship to citrus at all. However, many of these citrus relatives are used for ornamental, culinary, or religious purposes. ...

  16. Characterization of Xanthomonas spp. strains by bacteriocins Caracterização de isolados de Xanthomonas spp. por bacterocinas

    Directory of Open Access Journals (Sweden)

    Marcel Bonini

    2007-03-01

    Full Text Available Twenty-five strains of Xanthomonas axonopodis pv. citri and 14 strains of Xanthomonas spp. were tested for bacteriocin production. X. axonopodis pv. passiflorae strains were sensitive to the bacteriocins produced by the 25 X. axonopodis pv. citri strains evaluated in this study while strains of X. axonopodis pv. manihotis and X. campestris pv. campestris showed variable sensitivity. Only five of the 25 X. axonopodis pv. citri strains were not inhibited by the bacteriocins produced by the two X. axonopodis pv. passiflorae strains. The bacteriocins produced by the Xanthomonas axonopodis pv. citri (FDC-806 and X. axonopodis pv. passiflorae (Mar-2850 A strains were thermolabile, resistant to lysozyme and sensitive to DNAse. The bacteriocin produced by X. axonopodis pv. passiflorae was resistant to the action of proteinase K, trypsin and RNAse while the bacteriocin produced by X. axonopodis pv. citri was sensitive to these enzymes. The bacteriocins produced by X. axonopodis pv. passiflorae and X. axonopodis pv. citri were called passifloricin and citricin, respectively.Vinte e cinco isolados de Xanthomonas axonopodis pv. citri e 14 isolados de Xanthomonas spp. foram comparados a fim de verificar a capacidade de produção de bacteriocina e a sua sensibilidade. Isolados de X. axonopodis pv. passiflorae foram sensíveis às bacteriocinas produzidas por 25 isolados de X. axonopodis pv. citri avaliados e os isolados de X. axonopodis pv. manihotis e X. campestris pv. campestris apresentaram sensibilidade variável. Dos 25 isolados de X. axonopodis pv. citri apenas cinco não foram inibidos pelas bacteriocinas produzidas por dois isolados de X. axonopodis pv. passiflorae. As bacteriocinas produzidas pelos isolados de X. axonopodis pv. citri (FDC-806 e de X. axonopodis pv. passiflorae (Mar-2850 A foram termolábeis e resistentes à lisozima e sensíveis a DNAse. A bacteriocina produzida pelo isolado de X. axonopodis pv. passiflorae foi resistente à a

  17. The Asc locus for resistance to Alternaria stem canker in tomato does not encode the enzyme aspartate carbamoyltransferase

    NARCIS (Netherlands)

    Overduin, Bert; Hogenhout, Saskia A.; Biezen, Erik A. van der; Haring, Michel A.; Nijkamp, H. John J.; Hille, Jacques

    1993-01-01

    The fungal disease resistance locus Alternaria stem canker (Asc) in tomato has been suggested to encode the enzyme aspartate carbamoyltransferase (ACTase). To test this hypothesis a segment of the tomato ACTase gene was amplified by the polymerase chain reaction (PCR) using degenerate primers. The P

  18. Tomato resistance to Alternaria stem canker : localization in host genotypes and functional expression compared to non-host resistance

    NARCIS (Netherlands)

    Witsenboer, H.M.A.; Griend, E.G. van de; Tiersma, J.B.; Nijkamp, H.J.J.; Hille, J.

    1989-01-01

    The Alternaria stem canker resistance locus (Asc-locus), involved in resistance to the fungal pathogen Alternaria alternata f. sp. lycopersici and in insensitivity to host-specific toxins (AAL-toxins) produced by the pathogen, was genetically mapped on the tomato genome. Susceptibility and resistanc

  19. Asian citrus psyllid RNAi pathway : RNAi evidence

    OpenAIRE

    Taning, Clauvis N. T.; Andrade, Eduardo C.; Hunter, Wayne B.; Olivier Christiaens; Guy Smagghe

    2016-01-01

    Diaphorina citri, known as the Asian citrus psyllid, is an important pest of citrus because it transmits a phloem-limited bacteria strongly implicated in huanglongbing (citrus greening disease). Emerging biotechnologies, such as RNA interference, could provide a new sustainable and environmentally friendly strategy for the management of this pest. In this study, genome and functional analysis were performed to verify whether the RNAi core genes are present in the Asian psyllid genome and if t...

  20. Citrus allergy from pollen to clinical symptoms.

    Directory of Open Access Journals (Sweden)

    Rosa Anna Iorio

    Full Text Available Allergy to citrus fruits is often associated with pollinosis and sensitization to other plants due to a phenomenon of cross-reactivity. The aims of the present study were to highlight the cross-reactivity among citrus and the major allergenic pollens/fruits, throughout clinical and molecular investigations, and to evaluate the sensitization frequency to citrus fruits in a population of children and adults with pollinosis. We found a relevant percentage of sensitisation (39% to citrus fruits in the patients recruited and in all of them the IgE-mediated mechanism has been confirmed by the positive response to the prick-to-prick test. RT-PCR experiments showed the expression of Cit s 1, Cit s 3 and a profilin isoform, already described in apple, also in Citrus clementine pollen. Data of multiple sequence alignments demonstrated that Citrus allergens shared high percentage identity values with other clinically relevant species (i.e. Triticum aestivum, Malus domestica, confirming the possible cross-allergenicity citrus/grasses and citrus/apple. Finally, a novelty of the present work has been the expression of two phospholipaseA2 isoforms (PLA2 α and β in Citrus as well as in Triticum pollens; being PLA2 able to generate pro-inflammatory factors, this enzyme could participate in the activation of the allergenic inflammatory cascade.

  1. Green synthesis of gold nanoparticles using Citrus fruits (Citrus limon, Citrus reticulata and Citrus sinensis) aqueous extract and its characterization.

    Science.gov (United States)

    Sujitha, Mohanan V; Kannan, Soundarapandian

    2013-02-01

    This study reports the biological synthesis of gold nanoparticles by the reduction of HAuCl(4) by using citrus fruits (Citrus limon, Citrus reticulata and Citrus sinensis) juice extract as the reducing and stabilizing agent. A various shape and size of gold nanoparticles were formed when the ratio of the reactants were altered with respect to 1.0mM chloroauric acid solution. The gold nanoparticles obtained were characterized by UV-visible spectra, transmission electron microscopy (TEM) and X-ray diffraction (XRD). TEM studies showed the particles to be of various shapes and sizes and particle size ranges from 15 to 80 nm. Selected-area electron diffraction (SAED) pattern confirmed fcc phase and crystallinity of the particles. The X-ray diffraction analysis revealed the distinctive facets (111, 200, 220 and 222 planes) of gold nanoparticles. Dynamic light scattering (DLS) studies revealed that the average size for colloid gp(3) of C. limon, C. reticulata and C. sinensis are 32.2 nm, 43.4 nm and 56.7 nm respectively. The DLS graph showed that the particles size was larger and more polydispersed compared to the one observed by TEM due to the fact that the measured size also includes the bio-organic compounds enveloping the core of the Au NPs. Zeta potential value for gold nanoparticles obtained from colloid gp(3) of C. limon, C. reticulata and C. sinensis are -45.9, -37.9 and -31.4 respectively indicating the stability of the synthesized nanoparticles. Herein we propose a novel, previously unexploited method for the biological syntheses of polymorphic gold nanoparticles with potent biological applications.

  2. Green synthesis of gold nanoparticles using Citrus fruits (Citrus limon, Citrus reticulata and Citrus sinensis) aqueous extract and its characterization

    Science.gov (United States)

    Sujitha, Mohanan V.; Kannan, Soundarapandian

    2013-02-01

    This study reports the biological synthesis of gold nanoparticles by the reduction of HAuCl4 by using citrus fruits (Citrus limon, Citrus reticulata and Citrus sinensis) juice extract as the reducing and stabilizing agent. A various shape and size of gold nanoparticles were formed when the ratio of the reactants were altered with respect to 1.0 mM chloroauric acid solution. The gold nanoparticles obtained were characterized by UV-visible spectra, transmission electron microscopy (TEM) and X-ray diffraction (XRD). TEM studies showed the particles to be of various shapes and sizes and particle size ranges from 15 to 80 nm. Selected-area electron diffraction (SAED) pattern confirmed fcc phase and crystallinity of the particles. The X-ray diffraction analysis revealed the distinctive facets (1 1 1, 2 0 0, 2 2 0 and 2 2 2 planes) of gold nanoparticles. Dynamic light scattering (DLS) studies revealed that the average size for colloid gp3 of C. limon, C. reticulata and C. sinensis are 32.2 nm, 43.4 nm and 56.7 nm respectively. The DLS graph showed that the particles size was larger and more polydispersed compared to the one observed by TEM due to the fact that the measured size also includes the bio-organic compounds enveloping the core of the Au NPs. Zeta potential value for gold nanoparticles obtained from colloid gp3 of C. limon, C. reticulata and C. sinensis are -45.9, -37.9 and -31.4 respectively indicating the stability of the synthesized nanoparticles. Herein we propose a novel, previously unexploited method for the biological syntheses of polymorphic gold nanoparticles with potent biological applications.

  3. A simple method for DNA isolation from Xanthomonas spp.

    Directory of Open Access Journals (Sweden)

    Gomes Luiz Humberto

    2000-01-01

    Full Text Available A simple DNA isolation method was developed with routine chemicals that yields high quality and integrity preparations when compared to some of the most well known protocols. The method described does not require the use of lysing enzymes, water bath and the DNA was obtained within 40 minutes The amount of nucleic acid extracted (measured in terms of absorbancy at 260 nm from strains of Xanthomonas spp., Pseudomonas spp. and Erwinia spp. was two to five times higher than that of the most commonly used method.

  4. Plant resistance within the Rutaceae to Asian citrus psyllid

    Science.gov (United States)

    USDA-ARS recently initiated research on host plant resistance to the Asian citrus psyllid. The psyllid is an important invasive pest of citrus in the United States because it transmits a serious disease of citrus known as huanglongbing (citrus greening). There is no cure for this bacterial disease. ...

  5. 7 CFR 319.56-38 - Citrus from Chile.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Citrus from Chile. 319.56-38 Section 319.56-38... from Chile. Clementines (Citrus reticulata Blanco var. Clementine), mandarins (Citrus reticulata Blanco), and tangerines (Citrus reticulata Blanco) may be imported into the United States from Chile,...

  6. A comparison of plant species for rearing Asian citrus psyllid

    Science.gov (United States)

    Five plant genotypes were compared with respect to Asian citrus psyllid (ACP) reproduction potential: Bergera koenigii, Citrus aurantiifolia, C. macrophylla, C. taiwanica and Murraya paniculata. Asian citrus psyllid reproduction is dependent on young flush and thus Asian citrus psyllid production po...

  7. Cryopreservation and Cryotherapy of Citrus Cultivars

    Science.gov (United States)

    Long-term conservation of Citrus clones can be accomplished by cryopreservation. Shoot tips will survive liquid nitrogen exposure and storage when appropriately desiccated and treated with cryoprotectant solutions. In our research, vegetative Citrus budwood is shipped from Riverside to Fort Collin...

  8. Citrus water use in South Africa

    CSIR Research Space (South Africa)

    Vahrmeijer, JT

    2012-09-01

    Full Text Available intervenes through policy instruments to influence water use behaviour. Citrus growers need to take heed of these changes in policy as the majority of citrus orchards are irrigated and more detailed information on seasonal water requirements and irrigation...

  9. Understanding the dynamics of citrus water use

    CSIR Research Space (South Africa)

    Taylor, NJ

    2012-12-01

    Full Text Available The quantification of water use of citrus orchards is important in order to prevent stress developing in the orchard and to avoid wasting precious water resources. Measurement of citrus orchard water use is not possible under all environ...

  10. Rapid cyling plant breeding in citrus

    Science.gov (United States)

    Resistance or tolerance to huanglongbing (HLB) and other important traits have been identified in several citrus types and relatives and associated markers should be identified soon. What is urgently needed in addition is an accelerated strategy for citrus variety breeding. Identification and use of...

  11. Canker and decline caused by Neofusiccocum parvum on Acacia melanoxylon in Italy

    Directory of Open Access Journals (Sweden)

    Sidoti A

    2016-12-01

    Full Text Available In the spring of 2012, in reforested areas of Peloritani Mountains (Sicily, Italy a severe dieback of Acacia melanoxylon R. Brown was observed. The main symptoms on both young and adults plants consisted of elongated cankers on the trunks and epicormic shoots, wilt of the canopy and dieback interested mostly aged trees. The woody tissues showed browning beyond the cankers. Sapwood and heartwood appeared decayed with a brown to gray-greenish discoloration. One fungal species was consistently isolated from infected woody tissues, which was morphologically attributed to Neofusiccocum sp. The sequencing of the ITS regions of a representative isolate allowed to identify (99% similarity the species Neofusiccocum parvum (Pennycook & Samuels Crous, Slippers and Phillips, teleomorph Botryosphaeria parva Pennycook & Samuels. The pathogenicity tests have reproduced symptoms similar to those observed in the field. N. parvum is the aetiologic agent of mortality of australian blackwood observed in Sicily and to our knowledge this is the first report of this fungus on Acacia melanoxylon. It is a generalist pathogen, cosmopolitan, present in many temperate areas, Mediterranean and subtropical. The older Peloritani Mountains populations of australian blackwood seem particularly susceptible to the pathogen, the latter favored by the lack of silvicultural interventions that generate interspecific and intraspecific competition, as well as the increase and spread of the fungus. To minimize the consequential damage is necessary to adopt sanitation measures that would lower the fungal inoculum and program substitutions of this exotic species with others that have multiple functions suited to environments (e.g., Chestnut or encouraging the establishment and development of native species, such as the holm oak and shrub.

  12. Adaptive potential of maritime pine (Pinus pinaster populations to the emerging pitch canker pathogen, Fusarium circinatum.

    Directory of Open Access Journals (Sweden)

    Margarita Elvira-Recuenco

    Full Text Available There is a concern on how emerging pests and diseases will affect the distribution range and adaptability of their host species, especially due to different conditions derived from climate change and growing globalization. Fusarium circinatum, which causes pitch canker disease in Pinus species, is an exotic pathogen of recent introduction in Spain that threatens its maritime pine (P. pinaster stands. To predict the impact this disease will have on the species, we examine host resistance traits and their genetic architecture. Resistance phenotyping was done in a clonal provenance/progeny trial, using three-year-old cuttings artificially inoculated with the pathogen and maintained under controlled environmental conditions. A total number of 670 ramets were assessed, distributed in 10 populations, with a total of 47 families, 2 to 5 half-sibs per family, and 3-7 ramets per clone. High genetic variation was found at the three hierarchical levels studied: population, family and clone, being both additive and non-additive effects important. Narrow-sense and broad-sense heritability estimates were relatively high, with respective values of 0.43-0.58 and 0.51-0.8, depending on the resistance traits measured (lesion length, lesion length rate, time to wilting, and survival. These values suggest the species' high capacity of evolutionary response to the F. circinatum pathogen. A population originated in Northern Spain was the most resistant, while another from Morocco was the most susceptible. The total number of plants that did not show lesion development or presented a small lesion (length<30 mm was 224 out of 670, indicating a high proportion of resistant trees in the offspring within the analyzed populations. We found large differences among populations and considerable genetic variation within populations, which should allow, through natural or artificial selection, the successful adaptation of maritime pine to pitch canker disease.

  13. Citrus quarantine, sanitary and certification programs in the USA. Prevention of introduction and distribution of citrus diseases

    Science.gov (United States)

    Citrus germplasm originated in Australasia, the Far East, and Africa, thus all citrus grown in the New World was imported. This importation of citrus also resulted in importation of graft transmissible pathogens of citrus, many of which are latent in their original host but can cause epidemics of t...

  14. Canker Sore

    Science.gov (United States)

    ... or other dental appliances, ask your dentist about orthodontic waxes to cover sharp edges. Reduce your stress. ... Treatment of recurrent aphthous stomatitis: A literature review. Journal of Clinical Experimental Dentistry. 2014;6:e168. Akintoye ...

  15. Comparative analysis of two bacteriophages of Xanthomonas arboricola pv. juglandis.

    Science.gov (United States)

    Dömötör, Dóra; Frank, Tamara; Rákhely, Gábor; Doffkay, Zsolt; Schneider, György; Kovács, Tamás

    2016-09-01

    Walnut blight caused by Xanthomonas arboricola pv. juglandis (Xaj) is one of the most frequent infective diseases of walnut, resulting in serious economic losses. One potential solution to control this disease could be the application of bacteriophages. In this study, 24 phages were isolated from soil and walnut aerial tissues infected with Xaj. Two polyvalent bacteriophages, Xaj2 and Xaj24 were chosen for further characterization including their morphological, physiological and genomic analyses. Xaj2 was classified as Siphoviridae whereas Xaj24 belonged to the Podoviridae family. Both phages demonstrated lytic effect on Xaj in laboratory trials. Complete genomes of Xaj2 and Xaj24 were determined. Genomes of Xaj2 and Xaj24 consisted of 49.241 and 44.861 nucleotides encoding 80 and 53 genes, respectively. Comparative genome analyses have revealed that Xaj2 had a unique genome sequence, while Xaj24 was a phiKMV-like phage and it was most similar to the Prado phage which is virulent for Xylella fastidiosa and Xanthomonas spp. In this study, we present the first two complete Xaj phage sequences enabling an insight into the genomics of Xaj phages.

  16. The WRKY Transcription Factor Family in Citrus: Valuable and Useful Candidate Genes for Citrus Breeding.

    Science.gov (United States)

    Ayadi, M; Hanana, M; Kharrat, N; Merchaoui, H; Marzoug, R Ben; Lauvergeat, V; Rebaï, A; Mzid, R

    2016-10-01

    WRKY transcription factors belong to a large family of plant transcriptional regulators whose members have been reported to be involved in a wide range of biological roles including plant development, adaptation to environmental constraints and response to several diseases. However, little or poor information is available about WRKY's in Citrus. The recent release of completely assembled genomes sequences of Citrus sinensis and Citrus clementina and the availability of ESTs sequences from other citrus species allowed us to perform a genome survey for Citrus WRKY proteins. In the present study, we identified 100 WRKY members from C. sinensis (51), C. clementina (48) and Citrus unshiu (1), and analyzed their chromosomal distribution, gene structure, gene duplication, syntenic relation and phylogenetic analysis. A phylogenetic tree of 100 Citrus WRKY sequences with their orthologs from Arabidopsis has distinguished seven groups. The CsWRKY genes were distributed across all ten sweet orange chromosomes. A comprehensive approach and an integrative analysis of Citrus WRKY gene expression revealed variable profiles of expression within tissues and stress conditions indicating functional diversification. Thus, candidate Citrus WRKY genes have been proposed as potentially involved in fruit acidification, essential oil biosynthesis and abiotic/biotic stress tolerance. Our results provided essential prerequisites for further WRKY genes cloning and functional analysis with an aim of citrus crop improvement.

  17. Xanthomonads and other yellow-pigmented, Xanthomonas-like bacteria associated with tomato seeds in Tanzania

    DEFF Research Database (Denmark)

    Mbega, Ernest Rashid; Wulff, Ednar Gadelha; Mabagala, R.B.

    2012-01-01

    Tomato (Solanum lycopersicum L.) seeds habour unique bacterial community that can be pathogenic or beneficial to their host. Xanthomonas causing bacterial leaf spot (BLSX) on tomato and other yellow-pigmented xanthomonads-like bacteria (XLB) that closely resemble BLSX were obtained from tomato...... the most diverse populations of XLB and BLSX as compared to Northern and Southern Tanzania. The predominant bacterial genera in tomato seeds were Stenotrophomonas, Sphingomonas, Chryseobacterium, Xanthomonas, Pantoea and Flavobacterium. All strains identified by Biolog as Xanthomonas with exception...... of Xanthomonas campestris pv. malvacearum, were pathogenic on tomato and pepper plants. Strains identified by Biolog as Sphingomonas sanguinis and Sphingomonas terrae also incited black rot symptoms on pepper leaves. However, bacterial strains belonging to the genus Stenotrophomonas, Chryseobacterium, Pantoea...

  18. Improved annotation of the insect vector of citrus greening disease: Biocuration by a diverse genomics community

    Science.gov (United States)

    The Asian citrus psyllid (Diaphorina citri Kuwayama) is the insect vector of the bacterium Candidatus Liberibacter asiaticus (CLas), the pathogen associated with citrus Huanglongbing (HLB, citrus greening). HLB threatens citrus production worldwide. Suppression or reduction of the insect vector usin...

  19. Annotation of the Asian citrus psyllid genome reveals a reduced innate immune system

    Science.gov (United States)

    Citrus production worldwide is currently facing significant losses due to citrus greening disease, also known as huanglongbing. The citrus greening bacteria, Candidatus Liberibacter asiaticus (CLas), is a persistent propagative pathogen transmitted by the Asian citrus psyllid, Diaphorina citri Kuway...

  20. Quantifying the Impacts of Systemic Acquired Resistance to Pitch Canker on Monterey Pine Growth Rate and Hyperspectral Reflectance

    Directory of Open Access Journals (Sweden)

    Gregory J. Reynolds

    2016-01-01

    Full Text Available Pitch canker, caused by Fusarium circinatum, is a disease affecting Monterey pine (Pinus radiata and many other pine species throughout the world. The impact of pitch canker on Pinus radiata may be limited by systemic acquired resistance (SAR, a phenomenon that elevates resistance to a pathogen after initial challenge by that pathogen or another microorganism. Allocation of resources to defense, as a consequence of SAR, is presumed to reduce resources available to support growth and reproduction, but specific fitness consequences associated with SAR in P. radiata have not been measured. To quantify impacts of SAR on growth rate, a 2 × 2 factorial experiment was established in which trees were either primed for SAR or unprimed, with half the trees in each of those two groups being inoculated with the pitch canker pathogen and the other half not inoculated. Priming for SAR was accomplished by inoculating one branch with F. circinatum and removing inoculated branches prior to subsequent challenge inoculations (= disease treatments. Disease treatments included three inoculations that were removed for measurement of lesion length, and three additional inoculations that remained on the tree as a representation of persistent disease. Control trees were mock inoculated with water. Main effects of priming and disease did not result in significant effects on growth rate. Based on hyperspectral canopy reflectance data, diseased trees were associated with higher difference vegetation index values and biomass. The absence of a negative impact on growth rate associated with SAR suggests that induction of resistance may have utility as a tool for management of pitch canker in plantations.

  1. Comparative genomic analysis of duplicated homoeologous regions involved in the resistance of Brassica napus to stem canker

    Directory of Open Access Journals (Sweden)

    Berline eFopa Fomeju

    2015-09-01

    Full Text Available All crop species are current or ancient polyploids. Following whole genome duplication, structural and functional modifications result in differential gene content or regulation in the duplicated regions, which can play a fundamental role in the diversification of genes underlying complex traits. We have investigated this issue in Brassica napus, a species with a highly duplicated genome, with the aim of studying the structural and functional organization of duplicated regions involved in quantitative resistance to stem canker, a disease caused by the fungal pathogen Leptosphaeria maculans. Genome-wide association analysis on two oilseed rape panels confirmed that duplicated regions of ancestral blocks E, J, R, U and W were involved in resistance to stem canker. The structural analysis of the duplicated genomic regions showed a higher gene density on the A genome than on the C genome and a better collinearity between homoeologous regions than paralogous regions, as overall in the whole B. napus genome. The three ancestral sub-genomes were involved in the resistance to stem canker and the fractionation profile of the duplicated regions corresponded to what was expected from results on the B. napus progenitors. About 60% of the genes identified in these duplicated regions were single-copy genes while less than 5% were retained in all the duplicated copies of a given ancestral block. Genes retained in several copies were mainly involved in response to stress, signaling or transcription regulation. Genes with resistance-associated markers were mainly retained in more than two copies. These results suggested that some genes underlying quantitative resistance to stem canker might be duplicated genes. Genes with a hydrolase activity that were retained in one copy or R-like genes might also account for resistance in some regions. Further analyses need to be conducted to indicate to what extent duplicated genes contribute to the expression of the

  2. Signaling pathways in a Citrus EST database

    Directory of Open Access Journals (Sweden)

    Angela Mehta

    2007-01-01

    Full Text Available Citrus spp. are economically important crops, which in Brazil are grown mainly in the State of São Paulo. Citrus cultures are attacked by several pathogens, causing severe yield losses. In order to better understand this culture, the Millenium Project (IAC Cordeirópolis was launched in order to sequence Citrus ESTs (expressed sequence tags from different tissues, including leaf, bark, fruit, root and flower. Plants were submitted to biotic and abiotic stresses and investigated under different development stages (adult vs. juvenile. Several cDNA libraries were constructed and the sequences obtained formed the Citrus ESTs database with almost 200,000 sequences. Searches were performed in the Citrus database to investigate the presence of different signaling pathway components. Several of the genes involved in the signaling of sugar, calcium, cytokinin, plant hormones, inositol phosphate, MAPKinase and COP9 were found in the citrus genome and are discussed in this paper. The results obtained may indicate that similar mechanisms described in other plants, such as Arabidopsis, occur in citrus. Further experimental studies must be conducted in order to understand the different signaling pathways present.

  3. Citrus breeding, genetics and genomics in Japan

    Science.gov (United States)

    Omura, Mitsuo; Shimada, Takehiko

    2016-01-01

    Citrus is one of the most cultivated fruits in the world, and satsuma mandarin (Citrus unshiu Marc.) is a major cultivated citrus in Japan. Many excellent cultivars derived from satsuma mandarin have been released through the improvement of mandarins using a conventional breeding method. The citrus breeding program is a lengthy process owing to the long juvenility, and it is predicted that marker-assisted selection (MAS) will overcome the obstacle and improve the efficiency of conventional breeding methods. To promote citrus molecular breeding in Japan, a genetic mapping was initiated in 1987, and the experimental tools and resources necessary for citrus functional genomics have been developed in relation to the physiological analysis of satsuma mandarin. In this paper, we review the progress of citrus breeding and genome researches in Japan and report the studies on genetic mapping, expression sequence tag cataloguing, and molecular characterization of breeding characteristics, mainly in terms of the metabolism of bio-functional substances as well as factors relating to, for example, fruit quality, disease resistance, polyembryony, and flowering. PMID:27069387

  4. Citrus breeding, genetics and genomics in Japan.

    Science.gov (United States)

    Omura, Mitsuo; Shimada, Takehiko

    2016-01-01

    Citrus is one of the most cultivated fruits in the world, and satsuma mandarin (Citrus unshiu Marc.) is a major cultivated citrus in Japan. Many excellent cultivars derived from satsuma mandarin have been released through the improvement of mandarins using a conventional breeding method. The citrus breeding program is a lengthy process owing to the long juvenility, and it is predicted that marker-assisted selection (MAS) will overcome the obstacle and improve the efficiency of conventional breeding methods. To promote citrus molecular breeding in Japan, a genetic mapping was initiated in 1987, and the experimental tools and resources necessary for citrus functional genomics have been developed in relation to the physiological analysis of satsuma mandarin. In this paper, we review the progress of citrus breeding and genome researches in Japan and report the studies on genetic mapping, expression sequence tag cataloguing, and molecular characterization of breeding characteristics, mainly in terms of the metabolism of bio-functional substances as well as factors relating to, for example, fruit quality, disease resistance, polyembryony, and flowering.

  5. Spatial relationships between nitrogen status and pitch canker disease in slash pine planted adjacent to a poultry operation

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Zamora, Isabel [Department of Soil and Water Science, University of Florida, Gainesville, FL 32611 (United States); Bliss, Christine [Department of Soil and Water Science, University of Florida, Gainesville, FL 32611 (United States); Jokela, Eric J. [School of Forest Resources and Conservation, University of Florida, PO Box 110410, Gainesville, FL 32611 (United States)]. E-mail: ejokela@ufl.edu; Comerford, N.B. [Department of Soil and Water Science, University of Florida, Gainesville, FL 32611 (United States); Grunwald, Sabine [Department of Soil and Water Science, University of Florida, Gainesville, FL 32611 (United States); Barnard, E. [Division of Forestry, Florida Department of Agriculture and Consumer Services, Gainesville, FL (United States); Vasquez, G.M. [Department of Soil and Water Science, University of Florida, Gainesville, FL 32611 (United States)

    2007-05-15

    Pitch canker disease (Fusarium circinatum Nirenberg and O'Donnell) causes serious shoot dieback, reduced growth and mortality in pines found in the southern and western USA, and has been linked to nutrient imbalances. Poultry houses with forced-air ventilation systems produce nitrogen (N) emissions. This study analyzed spatial correlations between pitch canker disease and foliar, forest floor, soil, and throughfall N in a slash pine (Pinus elliottii var. elliottii Engelm.) plantation adjacent to a poultry operation in north Florida, USA. Tissue and throughfall N concentrations were highest near the poultry houses and remained elevated for 400 m. Disease incidence ranged from 57-71% near the poultry houses and was spatially correlated with N levels. Similarly, stem mortality ranged from 41-53% in the most heavily impacted area, and declined to 0-9% at distances greater than 400 m. These results suggest that nutritional processes exacerbate changes in disease susceptibility and expression in slash pine. - Local emissions from poultry production appear to significantly contribute to the spatial distribution of N and pitch canker disease in managed slash pine ecosystems.

  6. Pollen as a possible pathway for the dissemination of Pseudomonas syringae pv. actinide and bacterial canker of kiwifruit

    Directory of Open Access Journals (Sweden)

    Rodanthi TONTOU

    2014-09-01

    Full Text Available Pollen collected in a kiwifruit orchard with symptoms of bacterial canker and naturally contaminated by Pseudomonas syringae pv. actinidiae (Psa, was used to pollinate an experimental orchard, in order to confirm its role, under commercial orchard conditions, in disseminating the pathogen and, possibly, contributing to disease spread. A pollen lot, certified free from Psa, was used with the same methods as a control. Two pollination techniques were used: dusting (dry pollen and spraying (pollen suspension in water. The orchard was monitored during 2 years from experimental pollination, with regular sampling of flowers, fruits, leaves, and vines, to check for Psa as an epiphyte or endophyte, and for bacterial canker symptoms. Psa was recovered from flowers, fruitlets and leaves during the first season, mainly in plots where contaminated pollen had been sprayed in water suspension. From early August until harvesting time (mid-October, Psa detection was possible only on leaves. No symptoms developed during the first season after pollination. No endophytic Psa was detected in pruned vines in the following winter. During the second season, detection and isolation of Psa was erratic, but direct isolation was achieved from four plots. During the second season after pollination, typical leaf symptoms were observed on a few vines, and Psa was isolated and identified. Our results suggest that Psa could be disseminated via contaminated kiwifruit pollen as a pathway for spread of bacterial canker. However, further pollination experiments are needed to establish, beyond any doubt, whether contaminated pollen may contribute to possible disease outbreaks.

  7. Identification of the pathogen causing canker in eucalyptus%桉树溃疡病病原菌的鉴定

    Institute of Scientific and Technical Information of China (English)

    余磊; 郑建芬; 王荔芳; 赵建荣; 徐胜光; 高东; 黄琼

    2012-01-01

    The identification of the pathogens isolated from the canker of eucalyptus (Eucalyptus grandis) were carried out. Seventeen diseased eucalyptus samples were observed in Shilin and Honghe in Yunnan Province (south-western China). Seventeen isolates of possible pathogenic fungi were isolated from trunks and branches of infected eucalyptus plants. Bases on the pathogenicity experiment, the results showed that YNE1-YNE17 were the pathogens of eucalyptus (E. grandis) canker disease. The morphological identification showed that YNE1-YNE17 was identified as Botryosphaeria dothidea. By analysis of the rDNA internal transcribed spacer region (ITS1-5.8S-ITS2). BLAST searches at GenBank showed a high identity with reference sequences (99% -100% ). Representative sequences of both regions were deposited to GenBank (Accession No. FJ517657, FJ517658). Morphological and molecular identification confirmed this species as B. dothidea. B. dothidea was first reported as the pathogen of eucalyptus canker and shoot blight disease in China.

  8. 78 FR 8435 - Importation of Fresh Citrus Fruit From Uruguay, Including Citrus Hybrids and Fortunella

    Science.gov (United States)

    2013-02-06

    ... States through the importation of citrus fruit. These include two fruit flies, Anastrepha fraterculus... conditions are designed to prevent the introduction of the following quarantine pests: Anastrepha fraterculus...

  9. Comparison of antifungal activities of Vietnamese citrus essential oils.

    Science.gov (United States)

    Van Hung, Pham; Chi, Pham Thi Lan; Phi, Nguyen Thi Lan

    2013-03-01

    Citrus essential oils (EOs) are volatile compounds from citrus peels and widely used in perfumes, cosmetics, soaps and aromatherapy. In this study, inhibition of citrus EOs extracted from Vietnamese orange (Citrus sinensis), mandarin (Citrus reticulata Blanco), pomelo (Citrus grandis Osbeck) and lime (Citrus aurantifolia Swingle) on the growth of plant pathogenic fungi, Mucor hiemalis, Penicillium expansum and Fusarium proliferatum was investigated. The EOs of the citrus peels were obtained by cold-pressing method and the antifungal activity of EOs was evaluated using the agar dilution method. The results show that the EOs had significant antifungal activity. Lime EO was the best inhibitor of M. hiemalis and F. proliferatum while pomelo EO was the most effective against P. expansum. These results indicate that citrus EOs can be used as antifungal natural products in the food, pharmaceutical and cosmetic industries.

  10. Tranformasi Fragmen Dna Kromosom Xanthomonas Campestris ke dalam Escherichia Coli

    Directory of Open Access Journals (Sweden)

    Wibowo Mangunwardoyo

    2002-04-01

    Full Text Available Research on DNA transformation of Xanthomonas campestris into Escherichia coli DH5αα using plasmid vector Escherichia coli (pUC19. was carried out. DNA chromosome was isolated using CTAB method, alkali lysis method was used to isolate DNA plasmid. Both of DNA plasmid and chromosome were digested using restriction enzyme EcoRI. Competent cell was prepared with CaCl2 and heat shock method for transformation procedure. The result revealed transformation obtain 5 white colonies, with transformation frequency was 1,22 x 10-8 colony/competent cell. Electrophoresis analysis showed the DNA fragment (insert in range 0.5 – 7,5 kb. Further research should be carried out to prepare the genomic library to obtain better result of transformant.

  11. Biofertilizantes no controle da mancha bacteriana (Xanthomonas spp. do tomateiro

    Directory of Open Access Journals (Sweden)

    Vinícius William Borges Rodrigues

    2016-03-01

    Full Text Available RESUMO A mancha bacteriana do tomateiro, causada por quatro espécies de Xanthomonas pode provocar perdas significativas na produção da cultura e a utilização de biofertilizantes na proteção de plantas tende a reduzir a incidência de doenças. O objetivo do trabalho foi avaliar o efeito dos biofertilizantes no controle preventivo e curativo da mancha bacteriana do tomateiro. Para o controle preventivo da doença, plantas de tomate cultivar Santa Cruz Kada, com 3 a 4 folhas foram pulverizadas com os biofertilizantes (Soil-Set, Agro-Mos e Cop-R-Quick e água (testemunha; e dois dias após foram inoculadas por aspersão com a suspensão bacteriana nas concentrações 109 UFC mL-1 (OD550=0,5 e 106UFC mL-1, com o isolado UFU A35 de Xanthomonas sp. Para o controle curativo, as plantas foram inoculadas com a suspensão bacteriana, e dois dias após foram pulverizadas com os biofertilizantes e água. A severidade da mancha bacteriana foi avaliada usando uma escala diagramática; aos 3, 5, 8, 11 e 14 dias após a inoculação e calculada a área abaixo da curva de progresso de doença (AACPD. O controle preventivo foi mais eficiente no manejo da mancha bacteriana do tomateiro, e os diferentes biofertilizantes reduziram a severidade da doença.

  12. 2004 SWFWMD Citrus County Lidar Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This metadata record describes the ortho & LIDAR mapping of Citrus County, FL. The mapping consists of LIDAR data collection, contour generation, and production...

  13. The aconitate hydratase family from Citrus

    Directory of Open Access Journals (Sweden)

    Cercos Manuel

    2010-10-01

    Full Text Available Abstract Background Research on citrus fruit ripening has received considerable attention because of the importance of citrus fruits for the human diet. Organic acids are among the main determinants of taste and organoleptic quality of fruits and hence the control of fruit acidity loss has a strong economical relevance. In citrus, organic acids accumulate in the juice sac cells of developing fruits and are catabolized thereafter during ripening. Aconitase, that transforms citrate to isocitrate, is the first step of citric acid catabolism and a major component of the citrate utilization machinery. In this work, the citrus aconitase gene family was first characterized and a phylogenetic analysis was then carried out in order to understand the evolutionary history of this family in plants. Gene expression analyses of the citrus aconitase family were subsequently performed in several acidic and acidless genotypes to elucidate their involvement in acid homeostasis. Results Analysis of 460,000 citrus ESTs, followed by sequencing of complete cDNA clones, identified in citrus 3 transcription units coding for putatively active aconitate hydratase proteins, named as CcAco1, CcAco2 and CcAco3. A phylogenetic study carried on the Aco family in 14 plant species, shows the presence of 5 Aco subfamilies, and that the ancestor of monocot and dicot species shared at least one Aco gene. Real-time RT-PCR expression analyses of the three aconitase citrus genes were performed in pulp tissues along fruit development in acidic and acidless citrus varieties such as mandarins, oranges and lemons. While CcAco3 expression was always low, CcAco1 and CcAco2 genes were generally induced during the rapid phase of fruit growth along with the maximum in acidity and the beginning of the acid reduction. Two exceptions to this general pattern were found: 1 Clemenules mandarin failed inducing CcAco2 although acid levels were rapidly reduced; and 2 the acidless "Sucreña" orange

  14. Antihyperlipidemic effects of Citrus sinensis, Citrus paradisi, and their combinations

    Directory of Open Access Journals (Sweden)

    Neelam Mallick

    2016-01-01

    Full Text Available Objective: Hyperlipidemia, extensively contributes in the progression of coronary heart diseases and atherosclerosis, but may be managed through alterations in the nutritional pattern. Several studies show that diet rich in polyphenols and antioxidants have antiatherogenic effects. Citrus sinensis and Citrus paradisi are widely known for health benefits and have found to produce antioxidant, anti-inflammatory, and hypolipidemic effects, hence current research was planned to determine the hypolipidemic effects of C. sinensis and C. paradisi in rats receiving diet rich in cholesterol. Materials and Methods: All rats were divided into 11 groups each comprising 10 animals: Normal control group and hyperlipidemic control. C. sinensis treated three groups, C. paradisi treated three groups, C. sinensis and C. paradisi combination treated two groups, and group treated atorvastatin. All rats in the respective groups were treated orally with sterile water, juices, and standard drug for 8 weeks and lipid profile was estimated at the end of dosing. Results: Cholesterol, triglycerides (TGs, and low-density lipoprotein (LDL were decreased at all the three doses of C. sinensis and C. paradisi but rise in high-density lipoprotein (HDL was only significant at 8 ml/kg, and 0.3 ml/kg, respectively. Animals received the combination doses of C. sinensis and C. paradisi also showed a highly significant fall in cholesterol, LDL, and TGs, however HDL level was significantly elevated by SPJ-2 combination. Conclusion: Results suggest that C. sinensis and C. paradisi possess antihyperlipidemic activity due to phytochemicals and other essential nutrients, hence may serve as cardioprotective by preventing thrombosis.

  15. Clavibacter michiganensis subsp. michiganensis, Bacterial Canker of Tomato: 1. Conventional and Molecular Identification

    Directory of Open Access Journals (Sweden)

    Svetlana Milijašević

    2006-01-01

    Full Text Available In May 2006, tomato leaves with watersoaked areas between leaf veins were detected in glasshouses in Padinska Skela. The early-stage symptoms were followed by rapid desiccation to white and pale brown necrosis and subsequently by wilting of entire tomato plants. In June 2006, symptoms of bacterial canker and wilt were also recorded in manygreenhouses in the Jablanica County in southern Serbia.Samples of diseased tomato plants were collected from several tomato-growing regions in Serbia in order to identify the causal agent using conventional identification methods (isolation, pathogenicity and bacteriological determinative tests. Another objectiveof this study was to confirm the identity of isolated bacterial strains by polymerase chain reaction (PCR method.According to the morphological characteristics observed on NA and NBY media, biochemical characteristics, hypersensitive response in four-o’clock plant leaves and pathogenicity test on tomato seedlings, the investigated strains were identified as C. michiganensis subsp. michiganensis. To confirm the identity of isolated strains two PCR protocols were used. Amplification of expected length DNA fragments, 614 bp and 270 bp, respectively, confirmed that the investigated strains belonged to C. michiganensis subsp. michiganensis.

  16. De novo genome assembly of Geosmithia morbida, the causal agent of thousand cankers disease.

    Science.gov (United States)

    Schuelke, Taruna A; Westbrook, Anthony; Broders, Kirk; Woeste, Keith; MacManes, Matthew D

    2016-01-01

    Geosmithia morbida is a filamentous ascomycete that causes thousand cankers disease in the eastern black walnut tree. This pathogen is commonly found in the western U.S.; however, recently the disease was also detected in several eastern states where the black walnut lumber industry is concentrated. G. morbida is one of two known phytopathogens within the genus Geosmithia, and it is vectored into the host tree via the walnut twig beetle. We present the first de novo draft genome of G. morbida. It is 26.5 Mbp in length and contains less than 1% repetitive elements. The genome possesses an estimated 6,273 genes, 277 of which are predicted to encode proteins with unknown functions. Approximately 31.5% of the proteins in G. morbida are homologous to proteins involved in pathogenicity, and 5.6% of the proteins contain signal peptides that indicate these proteins are secreted. Several studies have investigated the evolution of pathogenicity in pathogens of agricultural crops; forest fungal pathogens are often neglected because research efforts are focused on food crops. G. morbida is one of the few tree phytopathogens to be sequenced, assembled and annotated. The first draft genome of G. morbida serves as a valuable tool for comprehending the underlying molecular and evolutionary mechanisms behind pathogenesis within the Geosmithia genus.

  17. Bio-control trials of Chaetomium spirale ND35 against apple canker

    Institute of Scientific and Technical Information of China (English)

    XINYa-fen; SHANGJin-jie

    2005-01-01

    A new endophytic antagonistic fungus, Chaetomium spirale ND35 from Populus tomentosa, was reported. The bio-control trials of C. spirale ND35 against the Valsa Canker of apple were preliminarily investigated. The results of dual culture on PDA plate showed that C. spirale ND35 was capable of strong antagonism against Valsa ceratosperma, and for inhibiting the mycelial growth of V. ceratosperma,.the crude extract of liquid culture of corn steep powder broth was more effective than that one of malt extract broth (MEB). The results of bio-control in greenhouse and field indicated that the disease incidence of apple tree treated with C. spirale ND35 was lower significantly than that treated by other methods. The re-isolation experiment suggested that C. spirale ND35 could colonize in stems and branches of apple trees successfully, and the ND35 colonization rate of the treatment with solid wheat bran culture was higher than that of corn steep powder broth, but the field experiment result the control effect of liquid culture of C. spirale ND35 was better than that of solid culture.

  18. Description of Acinetobacter populi sp. nov. isolated from symptomatic bark of Populus x euramericana canker.

    Science.gov (United States)

    Li, Yong; Chang, Jupu; Guo, Li-min; Wang, Hai-Ming; Xie, Shou-jiang; Piao, Chun-gen; He, Wei

    2015-12-01

    Five Gram-negative, non-motile, rod-shaped bacterial strains were isolated from cankers of Populus x euramericana collected from different locations in Puyang city, Henan Province, China. The five strains were characterized by nutritional and physiological testing and DNA sequence analysis. Haemolysis was not observed on agar media supplemented with sheep erythrocytes. The strains could be distinguished from members of most species of the genus Acinetobacter by their inability to assimilate L-arginine and benzoate. The five strains formed a single branch in phylogenetic trees based on 16S rRNA, gyrB and rpoB individual gene sequence analysis,indicating that they all belonged to a single taxon within the genus Acinetobacter. DNA-DNA hybridization results indicated that the five isolates represented to a single species that was separate from Acinetobacter puyangensis. On the basis of the phenotypic, genotypic and phylogenetic characteristics, the five strains are considered to represent a novel species of the genus Acinetobacter, for which the name Acinetobacter populi sp. nov. is proposed. The typestrain of A. populi sp. nov. is PBJ7T (CFCC 11170T=KCTC 42272T).

  19. 78 FR 41259 - Importation of Fresh Citrus Fruit From Uruguay, Including Citrus

    Science.gov (United States)

    2013-07-10

    ... that this argument is invalid due to the year-round marketing of citrus harvested domestically. We made... variety. Total citrus production in Uruguay in 2011 was 270,367 metric tons, which is less than 3 percent... metric tons, respectively, which is less than 3.2 percent of U.S. production and 1 percent of total...

  20. H NMR analyses of Citrus macrophylla subjected to Asian citrus psyllid (Diaphorina citri Kuwayama) feeding

    Science.gov (United States)

    The Asian citrus psyllid (ACP) is a phloem feeding insect that can host and transmit the bacterium Candidatus Liberibacter asiaticus (CLas), which is the putative causative agent of the economically important citrus disease, Huanglongbing (HLB). ACP are widespread in Florida, and are spreading in Ca...

  1. Interrelations between citrus rust mite, Hirsutella thompsonii and greasy spot on citrus in Surinam

    NARCIS (Netherlands)

    Brussel, van E.W.

    1975-01-01

    Counts of citrus rust mite (Phyllocoptruta oleivora (Ashm.)) on leaves and fruit of citrus rose to a peak in the two dry seasons, the build up taking 4-5 weeks. It then decreased partly through infection by the entomogenous fungus Hirsutellathompsonii Fisher and partly through a decline in feed qual

  2. Apparent tolerance to huanglongbing in citrus and citrus-related germplasm

    Science.gov (United States)

    In a Ft. Pierce, Florida field planting, growth and huanglongbing (HLB) severity were assessed as indicators of HLB-tolerance on progenies of 83 seed-source accessions of citrus and citrus-relatives from the Riverside, California genebank. The HLB-pathogen (Candidatus Liberibacter asiaticus) and vec...

  3. Detection of non-typhoid Salmonella infection by citrus and citrus extracts in Lao PDR

    Institute of Scientific and Technical Information of China (English)

    Yutaka Midorikawa; Satoshi Nakamura; Rattanaphone Phetsouvanh; Manivanh Vongsouvaht; Kaoru Midorikawa

    2010-01-01

    Objective: To know the current state of non-typhoid Salmonella infection in Laos. To examine the usefulness of new screening methods for Salmonella using citrus. Methods: Non-typhoidSalmonella infection of person in Lao PDR was studied in this research (2004-2009). The site was Vientiane capital city in 2004. Research from rural villages locating suburb of Vientiane during 2005-2008 was carried out. Rural villages in Attapu province where ethnic minorities were living was searched for this study in 2009. During this research, to detect Salmonella strain, a new method using citrus and citrus extract named MY phenomenon that observing black ring (MIDO ring) on DHL agar was tried. The slice lemon and lime were used for this trial in 2004. After 2005, disk of ascorbic acid and citric acid were used for the device instead of citrus fruits itself. Results: During this research, 65 of 272 human samples (23.9%) were infected with non-typhoid Salmonella. Conclusions: During this study, the method using citrus and citrus extracts was accepted for the detection of Salmonella. This study shows that with citrus and citrus extract, detection of Salmonella is possible using only DHL media. Results suggest that infectious rate of non-typhoid Salmonella was high.

  4. Phyllosticta citriasiana sp. nov., the cause of Citrus tan spot of Citrus maxima in Asia

    NARCIS (Netherlands)

    Wulandari, N.F.; To-anun, C.; Hyde, K.D.; Duong, L.M.; Gruyter, de J.; Meffert, J.P.; Groenewald, J.Z.; Crous, P.W.

    2009-01-01

    Guignardia citricarpa, the causal agent of Citrus Black Spot, is subject to phytosanitary legislation in the European Union and the U.S.A. This species is frequently confused with G. mangiferae, which is a non-pathogenic, and is commonly isolated as an endophyte from citrus fruits and a wide range o

  5. Phyllosticta citriasiana sp nov., the cause of Citrus tan spot of Citrus maxima in Asia

    NARCIS (Netherlands)

    Wulandari, N.F.; To-anun, C.; Hyde, K.D.; Duong, L.M.; de Gruyter, J.; Meffert, J.P.; Groenewald, J.Z.; Crous, P.W.

    2009-01-01

    Guignardia citricarpa, the causal agent of Citrus Black Spot, is subject to phytosanitary legislation in the European Union and the U.S.A. This species is frequently confused with G. mangiferae, which is a non-pathogenic, and is commonly isolated as an endophyte from citrus fruits and a wide range o

  6. Type IV Secretion System Is Not Involved in Infection Process in Citrus.

    Science.gov (United States)

    Jacob, Tiago Rinaldi; de Laia, Marcelo Luiz; Moreira, Leandro Marcio; Gonçalves, Janaína Fernandes; Carvalho, Flavia Maria de Souza; Ferro, Maria Inês Tiraboschi; Ferro, Jesus Aparecido

    2014-01-01

    The type IV secretion system (T4SS) is used by Gram-negative bacteria to translocate protein and DNA substrates across the cell envelope and into target cells. Xanthomonas citri subsp. citri contains two copies of the T4SS, one in the chromosome and the other is plasmid-encoded. To understand the conditions that induce expression of the T4SS in Xcc, we analyzed, in vitro and in planta, the expression of 18 ORFs from the T4SS and 7 hypothetical flanking genes by RT-qPCR. As a positive control, we also evaluated the expression of 29 ORFs from the type III secretion system (T3SS), since these genes are known to be expressed during plant infection condition, but not necessarily in standard culture medium. From the 29 T3SS genes analyzed by qPCR, only hrpA was downregulated at 72 h after inoculation. All genes associated with the T4SS were downregulated on Citrus leaves 72 h after inoculation. Our results showed that unlike the T3SS, the T4SS is not induced during the infection process.

  7. The complete chloroplast genome sequence of Citrus sinensis (L. Osbeck var 'Ridge Pineapple': organization and phylogenetic relationships to other angiosperms

    Directory of Open Access Journals (Sweden)

    Jansen Robert K

    2006-09-01

    Full Text Available Abstract Background The production of Citrus, the largest fruit crop of international economic value, has recently been imperiled due to the introduction of the bacterial disease Citrus canker. No significant improvements have been made to combat this disease by plant breeding and nuclear transgenic approaches. Chloroplast genetic engineering has a number of advantages over nuclear transformation; it not only increases transgene expression but also facilitates transgene containment, which is one of the major impediments for development of transgenic trees. We have sequenced the Citrus chloroplast genome to facilitate genetic improvement of this crop and to assess phylogenetic relationships among major lineages of angiosperms. Results The complete chloroplast genome sequence of Citrus sinensis is 160,129 bp in length, and contains 133 genes (89 protein-coding, 4 rRNAs and 30 distinct tRNAs. Genome organization is very similar to the inferred ancestral angiosperm chloroplast genome. However, in Citrus the infA gene is absent. The inverted repeat region has expanded to duplicate rps19 and the first 84 amino acids of rpl22. The rpl22 gene in the IRb region has a nonsense mutation resulting in 9 stop codons. This was confirmed by PCR amplification and sequencing using primers that flank the IR/LSC boundaries. Repeat analysis identified 29 direct and inverted repeats 30 bp or longer with a sequence identity ≥ 90%. Comparison of protein-coding sequences with expressed sequence tags revealed six putative RNA edits, five of which resulted in non-synonymous modifications in petL, psbH, ycf2 and ndhA. Phylogenetic analyses using maximum parsimony (MP and maximum likelihood (ML methods of a dataset composed of 61 protein-coding genes for 30 taxa provide strong support for the monophyly of several major clades of angiosperms, including monocots, eudicots, rosids and asterids. The MP and ML trees are incongruent in three areas: the position of Amborella and

  8. Crestamento foliar, nova sintomatologia em algodoeiro causada por Xanthomonas axonopodis pv. malvacearum Cotton leaf blight, a new symptomatology caused by Xanthomonas axonopodis pv. malvacearum

    Directory of Open Access Journals (Sweden)

    Valdemar Atílio Malavolta Jr.

    2008-06-01

    Full Text Available Foi observada recentemente no Estado de São Paulo uma nova sintomatologia em algodoeiro cv. Makina, IAC 24 e Detaopal, causada por Xanthomonas axonopodis pv. malvacearum (Xam, denominada "crestamento foliar". Caracteriza-se por crestamento foliar, geralmente acompanhado por halo clorótico, podendo também causar sintomas de "V" invertido, a partir dos bordos foliares. Linhagens de Xam foram comparadas, por meio de testes de patogenicidade, bioquímicos, sorológicos, culturais e PCR-RFLP da região espaçadora 16S-23S DNAr. Independentemente do tipo de sintoma, as linhagens apresentaram características e perfis idênticos aos apresentados pela linhagem tipo, confirmando a identidade dos isolados como Xanthomonas axonopodis pv. malvacearum.Recently a new symptomatology on cotton plants (cv. Makina, IAC 24 and Deltaopal caused by Xanthomonas axonopodis pv. malvacearum (Xam was observed in São Paulo state, Brazil, and named "bacterial leaf blight". The symptom was characterized by leaf blight, generally exhibiting chlorotic haloes and sometimes showing V-shaped lesions beginning at the leaves' border. Strains of Xam responsible for typical angular leaf spots and bacterial leaf blight were compared through pathological, biochemical, serological, cultural and RFLP-PCR tests of the 16S-23S spacer region. Independently of the symptom type, the strains exhibited characteristics and profiles that were identical to those exhibited by the type strain, which confirms the isolates identity Xanthomonas axonopodis pv. malvacearum

  9. Mathematical modeling of citrus groves infected by huanglongbing.

    Science.gov (United States)

    Jacobsen, Karly; Stupiansky, Jillian; Pilyugin, Sergei S

    2013-06-01

    Huanglongbing (citrus greening) is a bacterial disease that is significantly impacting the citrus industry in Florida and poses a risk to the remaining citrus-producing regions of the United States. A mathematical model of a grove infected by citrus greening is developed. An equilibrium stability analysis is presented. The basic reproductive number and its relation to the persistence of the disease is discussed. A numerical study is performed to illustrate the theoretical findings.

  10. First report of citrus leprosis virus nuclear type in Colombia

    Science.gov (United States)

    Citrus leprosis is a difficult viral disease causing significant damage to citrus fruit in South America and Central America. The disease is marked by dramatic lesions on fruit, leaves and stems resulting in unmarketable product. Citrus leprosis virus cytoplasmic types (CiLV-C and CiLV-C2) wer edete...

  11. Trailers transporting oranges to processing plants move Asian citrus psyllids

    Science.gov (United States)

    Huanglongbing (citrus greening) is one of the most serious of citrus diseases. Movement of the disease occurs as a result of natural vector-borne infection and by movement of plant material. We demonstrate here that Diaphorina citri Kuwayama (vector of citrus greening pathogens) can be transported i...

  12. Wavelength and polarization affect phototaxis of the Asian citrus psyllid

    Science.gov (United States)

    The Asian citrus psyllid, D. citri, is a primary pest for citrus production due to its status as a vector of the citrus disease, huanglongbing. We investigated phototactic behavior of D. citri to evaluate effects of light of specific wavelength or polarization using a horizontal bioassay arena. Wave...

  13. Current California Drought: Impact on Citrus Trees and Potential Mitigation

    Science.gov (United States)

    California is in another cycle of extended drought. The article reviews and discusses likely impact of the current drought on citrus growers and potential mitigation techniques. Citrus physiological responses to water stress is briefly reviewed. The direct impact of drought on citrus is reduced frui...

  14. Biological Indexing of Graft Transmissible Diseases of Citrus

    Science.gov (United States)

    Biological indexing for the detection of graft transmissible diseases of citrus is essential for maintaining a citrus certification program. Many of the graft transmissible diseases of citrus are harbored as latent infections in the scions, but when propagated on a susceptible rootstock that allow...

  15. Genome wide selection in Citrus breeding.

    Science.gov (United States)

    Gois, I B; Borém, A; Cristofani-Yaly, M; de Resende, M D V; Azevedo, C F; Bastianel, M; Novelli, V M; Machado, M A

    2016-10-17

    Genome wide selection (GWS) is essential for the genetic improvement of perennial species such as Citrus because of its ability to increase gain per unit time and to enable the efficient selection of characteristics with low heritability. This study assessed GWS efficiency in a population of Citrus and compared it with selection based on phenotypic data. A total of 180 individual trees from a cross between Pera sweet orange (Citrus sinensis Osbeck) and Murcott tangor (Citrus sinensis Osbeck x Citrus reticulata Blanco) were evaluated for 10 characteristics related to fruit quality. The hybrids were genotyped using 5287 DArT_seq(TM) (diversity arrays technology) molecular markers and their effects on phenotypes were predicted using the random regression - best linear unbiased predictor (rr-BLUP) method. The predictive ability, prediction bias, and accuracy of GWS were estimated to verify its effectiveness for phenotype prediction. The proportion of genetic variance explained by the markers was also computed. The heritability of the traits, as determined by markers, was 16-28%. The predictive ability of these markers ranged from 0.53 to 0.64, and the regression coefficients between predicted and observed phenotypes were close to unity. Over 35% of the genetic variance was accounted for by the markers. Accuracy estimates with GWS were lower than those obtained by phenotypic analysis; however, GWS was superior in terms of genetic gain per unit time. Thus, GWS may be useful for Citrus breeding as it can predict phenotypes early and accurately, and reduce the length of the selection cycle. This study demonstrates the feasibility of genomic selection in Citrus.

  16. Multimodal Generally Recognized as Safe ZnO/Nanocopper Composite: A Novel Antimicrobial Material for the Management of Citrus Phytopathogens.

    Science.gov (United States)

    Young, Mikaeel; Ozcan, Ali; Myers, Monty E; Johnson, Evan G; Graham, James H; Santra, Swadeshmukul

    2017-09-05

    Copper (Cu) bactericides/fungicides are used extensively for crop protection in agriculture. Concerns for Cu accumulation in soil, Cu leaching into the surrounding ecosystem, and development of Cu resistance in phytopathogenic bacteria are evident. While there is no suitable alternative to Cu available to date for agricultural uses, it is possible to reduce Cu per application by supplementing with Zn and improving Cu bioavailability using nanotechnology. We have prepared a non-phytotoxic composite material consisting of generally recognized as safe ZnO 800 particles and nanocopper-loaded silica gel (ZnO-nCuSi). The morphology of the ZnO-nCuSi material was characterized using scanning electron microscopy, showing ZnO particles dispersed in the silica gel matrix. ZnO-nCuSi demonstrated strong in vitro antimicrobial properties against several model plant bacterial species. Two consecutive year field efficacy results showed that agri-grade ZnO-nCuSi was effective in controlling citrus canker disease at less than half the metallic rate of the commercial cuprous oxide/zinc oxide pesticide.

  17. Incorporating exposure to pitch canker disease to support management decisions of Pinus pinaster Ait. in the face of climate change.

    Science.gov (United States)

    Serra-Varela, María Jesús; Alía, Ricardo; Pórtoles, Javier; Gonzalo, Julián; Soliño, Mario; Grivet, Delphine; Raposo, Rosa

    2017-01-01

    Climate change is gravely affecting forest ecosystems, resulting in large distribution shifts as well as in increasing infection diseases and biological invasions. Accordingly, forest management requires an evaluation of exposure to climate change that should integrate both its abiotic and biotic components. Here we address the implications of climate change in an emerging disease by analysing both the host species (Pinus pinaster, Maritime pine) and the pathogen's (Fusarium circinatum, pitch canker) environmental suitability i.e. estimating the host's risk of habitat loss and the disease`s future environmental range. We constrained our study area to the Spanish Iberian Peninsula, where accurate climate and pitch canker occurrence databases were available. While P. pinaster is widely distributed across the study area, the disease has only been detected in its north-central and north-western edges. We fitted species distribution models for the current distribution of the conifer and the disease. Then, these models were projected into nine Global Climate Models and two different climatic scenarios which totalled to 18 different future climate predictions representative of 2050. Based on the level of agreement among them, we created future suitability maps for the pine and for the disease independently, which were then used to assess exposure of current populations of P. pinaster to abiotic and biotic effects of climate change. Almost the entire distribution of P. pinaster in the Spanish Iberian Peninsula will be subjected to abiotic exposure likely to be driven by the predicted increase in drought events in the future. Furthermore, we detected a reduction in exposure to pitch canker that will be concentrated along the north-western edge of the study area. Setting up breeding programs is recommended in highly exposed and productive populations, while silvicultural methods and monitoring should be applied in those less productive, but still exposed, populations.

  18. Incorporating exposure to pitch canker disease to support management decisions of Pinus pinaster Ait. in the face of climate change

    Science.gov (United States)

    Serra-Varela, María Jesús; Alía, Ricardo; Pórtoles, Javier; Gonzalo, Julián; Soliño, Mario; Grivet, Delphine; Raposo, Rosa

    2017-01-01

    Climate change is gravely affecting forest ecosystems, resulting in large distribution shifts as well as in increasing infection diseases and biological invasions. Accordingly, forest management requires an evaluation of exposure to climate change that should integrate both its abiotic and biotic components. Here we address the implications of climate change in an emerging disease by analysing both the host species (Pinus pinaster, Maritime pine) and the pathogen’s (Fusarium circinatum, pitch canker) environmental suitability i.e. estimating the host’s risk of habitat loss and the disease`s future environmental range. We constrained our study area to the Spanish Iberian Peninsula, where accurate climate and pitch canker occurrence databases were available. While P. pinaster is widely distributed across the study area, the disease has only been detected in its north-central and north-western edges. We fitted species distribution models for the current distribution of the conifer and the disease. Then, these models were projected into nine Global Climate Models and two different climatic scenarios which totalled to 18 different future climate predictions representative of 2050. Based on the level of agreement among them, we created future suitability maps for the pine and for the disease independently, which were then used to assess exposure of current populations of P. pinaster to abiotic and biotic effects of climate change. Almost the entire distribution of P. pinaster in the Spanish Iberian Peninsula will be subjected to abiotic exposure likely to be driven by the predicted increase in drought events in the future. Furthermore, we detected a reduction in exposure to pitch canker that will be concentrated along the north-western edge of the study area. Setting up breeding programs is recommended in highly exposed and productive populations, while silvicultural methods and monitoring should be applied in those less productive, but still exposed, populations

  19. Degradation products of citrus volatile organic compounds (VOCs) acting as phagostimulants that increase probing behavior of Asian citrus psyllid

    Science.gov (United States)

    Volatile phytochemicals play a role in orientation by phytophagous insects. We studied antennal and behavioral responses of the Asian citrus psyllid, Diaphorina citri Kuwayama, vector of the citrus greening disease pathogen. Little or no response to citrus leaf volatiles was detected by electroanten...

  20. [Evaluation of culture media for detecting the starch hydrolysis reaction in pathovars of Xanthomonas campestris].

    Science.gov (United States)

    Alippi, A M

    1991-01-01

    Sixty strains of different pathovars of Xanthomonas campestris have been tested for the evaluation of various starch agars and compounds of starch degradation on six media: soluble starch, potato insoluble starch, corn insoluble starch, potato amylopectin, corn amylopectin and potato amylose. The purpose of the present investigation was the selection of the most suitable medium for the visualization of the starch hydrolysis test, presenting this reaction as a distinct character between pathovars of the Xanthomonas campestris group. From 60 strains tested, 74% gave positive reactions. Pathovars holcicola, pelargonii, pruni and vitians were negative. Regarding X. campestris pv. vesicatoria cultures, results were variable. Potato and corn insoluble starch agars were the most suitable media for the visualization of the starch hydrolysis reaction and at the same time the most appropriate for direct isolation. Differentiation at species level could be practicable, but within the Xanthomonas campestris group, variation amongst pathovars suggest the unsuitability of the test in spite of the high percentage of positive reactions.

  1. IDENTIFICATION AND QUANTIFICATION OF DIFFERENTIALLY EXPRESSED GENES ASSOCIATED WITH CITRUS BLIGHT (Citrus spp.

    Directory of Open Access Journals (Sweden)

    José Renato de Abreu

    2015-02-01

    Full Text Available Brazil is the largest citrus producer in the world, being responsible for more than 20% of its production, which is, however still low due to phytosanitary issues such as citrus blight. Citrus blight is an anomaly whose causes still have not yet been determined, therefore there are no efficient control measures to minimize the production losses with the use of resistant varieties being considered the most appropriate method. However, little is known about the genes involved in the defense response of the plants to this anomaly. Considering that many physiological alterations associated with plant stress responses are controlled at a transcriptional level, in this study we sought the identification and characterization of the gene expression products differentially expressed in the response to the citrus blight. Through the suppressive subtractive hybridization technique, expressed cDNA libraries were built using mRNAs isolated from "Cravo" lemon tree roots (Citrus limonia L. Osbeck under "Pera" orange (Citrus sinensis L. Osbeck of healthy and sick plants. 129 clones were obtained by subtraction and their sequences were compared in databases. 34 of them linked to proteins associated to stress processes, while the others were similar to sequences of unknown functions or did not present similarity with sequences deposited in the databases. 3 genes were selected and their expressions were studied by RT - qPCR in real-time. Plants with citrus blight presented an increase of the expression level in two of those genes, suggesting that these can be directly involved with this anomaly.

  2. Titers of 'Ca. Liberibacter asiaticus' in Murraya paniculata and Murraya-reared Diaphorina citri Are Much Lower than in Citrus and Citrus-reared Psyllids

    National Research Council Canada - National Science Library

    Walter, Abigail; Duan, Y; Hall, David G

    2012-01-01

    Huanglongbing, one of the most devastating diseases of citrus, is associated with the bacterium 'Candidatus Liberibacter asiaticus' vectored by the Asian citrus psyllid, Diaphorina citri, in North America...

  3. Caracterização de isolados de Xanthomonas axonopodis pv. manihotis = Characterization of isolates of Xanthomonas axonopodis pv. manihotis

    Directory of Open Access Journals (Sweden)

    Roberto Luis Portz

    2006-07-01

    Full Text Available A bacteriose (Xanthomonas axonopodis pv. manihotis e a doenca de maior importancia economica na cultura da mandioca. Para estudar a variabilidade genetica desta bacteria no Oeste do Parana, foram realizados levantamentos em Entre Rios do Oeste, Marechal Candido Rondon, Mercedes, Missal, Nova Santa Rosa e Pato Bragado. Os isolados foram caracterizados em relacao a atividade de amilase, ƒ¿ e ƒÀ-esterase e agressividade. Dos 61 materiais vegetais coletados, obtiveram-se 19 isolados da bacteria, com maior incidencia para variedades de mesa em relacao aqueles para industria. Manivas provenientes de Pato Bragado, Entre Rios do Oeste e Mercedes apresentaram incidencias de 10, 27 e 10%, respectivamente, valores inferiores aos de Marechal Candido Rondon (50% e Nova Santa Rosa (58%. Os isolados foram agrupados em cinco, seis e 12 grupos em relacao a capacidade amilolitica, agressividade e isoenzimas de esterase, respectivamente. Nao houve relacao entre atividade de amilase e agressividade. Isolados de Marechal Candido Rondon foram mais agressivos que os provenientes das outras regioes. O agrupamento com base em esterase permitiu verificar que isolados provenientes de Entre Rios do Oeste, Nova Santa Rosa e Mercedes apresentaram alto grau de similaridade. Estes resultados indicam haver diferenciacaoentre os isolados da bacteria presentes nos municipios amostrados.The bacterial blight (Xanthomonas axonopodis pv. manihotis is the most important disease of cassava. To study the genetic variability of pathogen in the West of Parana, a research was carried out at Entre Rios do Oeste, Marechal Candido Rondon, Mercedes, Missal, Nova Santa Rosa and Pato Bragado. The isolates were characterized to amylase activity, ƒ¿ and ƒÀ-esterase and aggressiveness. From 61 collected materials, were obtained 19 bacterial isolates, with larger incidence for varieties of human consume than those for industry. Stems from Pato Bragado, Entre Rios do Oeste and Mercedes

  4. Diversidade genómica, patogenicidade e sensibilidade a compostos bioactivos em Xanthomonas campestris

    OpenAIRE

    2009-01-01

    Tese de mestrado, Biologia (Biologia Celular e Biotecnologia), 2009, Universidade de Lisboa, Faculdade de Ciências O género Xanthomonas pertence à subdivisão gama de Proteobacteria, incluindo 27 espécies fitopatogénicas que infectam 124 espécies de plantas monocotiledóneas e 268 de dicotiledóneas. 121 isolados de Xanthomonas spp. foram sujeitos a uma caracterização genotípica, utilizando BOX-, ERIC- e MSP-PCR. Esta estratégia permitiu a tipificação dos isolados de X. fragariae e X. campest...

  5. Assessment of genetic diversity among different indigenous Xanthomonas isolates via RAPD and ISSR

    Directory of Open Access Journals (Sweden)

    Fatima Sabin

    2012-01-01

    Full Text Available The genetic diversity among seven Xanthomonas isolates representing four species was assessed using RAPD and ISSR PCR-based techniques. Both techniques revealed high degrees of polymorphisms among the studied isolates. A cluster dendrogram based on the combined data of RAPD and ISSR showed that genetic diversity exists in local isolates of Xanthomonas. In terms of percentage similarity values, the genomic variation was found to be in the range of 29.29% - 100% among the isolates. X. campestris (Mangifera indica remained unclustered in cluster dendrogram and revealed a unique genomic profile compared to other isolates used in this study.

  6. A genetically homogenous population of Fusarium circinatum causes pitch canker of Pinus radiata in the Basque Country, Spain.

    Science.gov (United States)

    Iturritxa, Eugenia; Ganley, Rebecca J; Wright, Jane; Heppe, Endika; Steenkamp, Emma T; Gordon, Thomas R; Wingfield, Michael J

    2011-03-01

    Pitch canker, caused by Fusarium circinatum, is a destructive disease of Pinus species and has recently been shown to represent a substantial threat to natural and commercial forests in northern Spain. The genetic diversity of F. circinatum in the Basque Country of Spain was assessed by characterising 96 isolates based on vegetative compatibility groups (VCGs), mating type assays, polymorphic DNA-markers and amplified fragment length polymorphism (AFLP) analyses. For this purpose, F. circinatum isolates were collected from diseased Pinus radiata as well as from insects associated with this host. Overall, a low level of diversity was detected in the population. The isolates represented only two VCGs and they were all of the same mating type. AFLP analyses revealed three genotypes and polymorphic DNA-markers specific for F. circinatum showed nine genotypes. The most common genotypes represented 97% of all isolates for AFLP analysis and 68% of isolates for the polymorphic DNA-marker sets. Over all, this indicates that pitch canker in the Basque Country of Spain is caused by a clonally propagating population of F. circinatum, typical of a recently introduced pathogen.

  7. Development of resistant tomato population with bacterial canker resistance genes from interspecific hybrids by the support of embryo rescue

    Directory of Open Access Journals (Sweden)

    Aylin KABAŞ

    2016-06-01

    Full Text Available Bacterial canker is one of the most important diseases causing economic yield loss in tomato production areas in the world. The best way to control for this disease is to use resistant varieties. However, there are few studies on variety breeding studies of this disease compared with other disease resistant breeding studies. In this study we aimed to improve inbred lines carrying bacterial canker resistance genes to use in the breeding of resistant varieties. Susceptible inbred line AK1 (S. esculentum and resistant LA2157 (S. peruvianum were crossed. Embryo rescue and ovule culture techniques were applied in 30 fruits to get F1 hybrids. Rescued embryos and immature ovules were cultured in petri dishes containing solidified MS medium without hormone. 30 healty embryos were excised and cultured from 30 fruits 27-61 day old (1 embryo fruit-1 in embryo rescue method. The two surviving plants from acclimatization were transferred to the greenhouse to get their BC1 progenies. Resistance tests were performed according to the stem inoculation method in the BC1 and BC2 progenies. The mixture of 14 aggressive Turkish Cmm strains were used to confirm the resistance. The plants were valued by 0-4 scale. Plants with 0 and 1 scale values were used to obtain next progenies. A total of 80 BC3 resistant progenies were transferred to our variety breeding programme.

  8. Variables Associated with Severity of Bacterial Canker and Wilt Caused by Clavibacter michiganensis subsp. michiganensis in Tomato Greenhouses.

    Science.gov (United States)

    Blank, L; Cohen, Y; Borenstein, M; Shulhani, R; Lofthouse, M; Sofer, M; Shtienberg, D

    2016-03-01

    Clavibacter michiganensis subsp. michiganensis, the causal agent of bacterial canker and wilt of tomato, is considered to be one of the most important bacterial pathogens worldwide. In the year 2000 there was an increase in the number of infected greenhouses and in the severity of the disease in Israel. As part of the effort to cope with the disease, a comprehensive survey was conducted. Scouts recorded disease severity monthly in 681 production units. At the end of the season the scouts met with the growers and together recorded relevant details about the crop and cultural practices employed. The results suggested an absence of anisotropy pattern in the study region. Global Moran's I analysis showed that disease severity had significant spatial autocorrelation. The strongest spatial autocorrelation occurred within a 1,500 m neighborhood, which is comparable to the distance between production units maintained by one grower (Farm). Next, we tested three groups of variables including or excluding the Farm as a variable. When the Farm was included the explained variation increased in all the studied models. Overall, results of this study demonstrate that the most influential factor on bacterial canker severity was the Farm. This variable probably encompasses variation in experience, differences in agricultural practices between growers, and the quality of implementation of management practices.

  9. A signature of tree health? Shifts in the microbiome and the ecological drivers of horse chestnut bleeding canker disease.

    Science.gov (United States)

    Koskella, Britt; Meaden, Sean; Crowther, William J; Leimu, Roosa; Metcalf, C Jessica E

    2017-07-01

    Host susceptibility to pathogens can be shaped by genetic, ecological, and evolutionary factors. The ability to predict the spread of disease therefore requires an integrated understanding of these factors, including effects of pests on pathogen growth and competition between pathogens and commensal microbiota for host resources. We examined interactions between the leaf-mining moth Cameraria ohridella, the bacterial causal agent of bleeding canker disease Pseudomonas syringae pv aesculi, and the bark-associated microbiota of horse chestnut (Aesculus hippocastanum) trees. Through surveys of > 900 trees from 60 sites in the UK, we tested for ecological or life history predictors of leaf miner infestation, bleeding canker, or coinfection. Using culture-independent sequencing, we then compared the bark microbiomes from 46 trees to measure the association between microbiome composition and key ecological variables, including the severity of disease. Both pest and pathogen were found to respond to tree characteristics, but neither explained damage inflicted by the other. However, we found a clear loss of microbial diversity and associated shift in microbiome composition of trees as a function of disease. These results show a link between bark-associated microbiota and tree health that introduces the intriguing possibility that tree microbiota play key roles in the spread of disease. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  10. ENZYMATIC KINETIC STUDY HYDROLASE FROM CITRUS

    Directory of Open Access Journals (Sweden)

    Israel Hernández

    2015-09-01

    Full Text Available In this paper the degrading activity of enzymes derived from orange peels (Citrus x sinensis, grapefruit (Citrus paradise and pineapple (Ananas comosus on the organic matter in wastewater is evaluated. This activity is measured indirectly by quantifying the biochemical oxygen demand (COD before and after degradation process based on a period of time using the HACH DR / 2010, and then the kinetic study was performed by the differential method and integral with the experimental data, obtaining a reaction order of 1 to pectinase (orange, and order 2 for bromelain (pineapple.

  11. Development of SSR markers from Citrus clementina (Rutaceae) BAC end sequences and interspecific transferability in Citrus.

    Science.gov (United States)

    Ollitrault, Frédérique; Terol, Javier; Pina, Jose Antonio; Navarro, Luis; Talon, Manuel; Ollitrault, Patrick

    2010-11-01

    Microsatellite primers were developed from bacterial artificial chromosome (BAC) end sequences of Citrus clementina and their transferability and polymorphism tested in the genus Citrus for future anchorage of physical and genetic maps and comparative interspecific genetic mapping. • Using PAGE and DNA silver staining, 79 primer pairs were selected for their transferability and polymorphism among 526 microsatellites mined in BES. A preliminary diversity study in Citrus was conducted with 18 of them, in C. reticulata, C. maxima, C. medica, C. sinensis, C. aurantium, C. paradisi, C. lemon, C. aurantifolia, and some papedas (wild citrus), using a capillary electrophoresis fragment analyzer. Intra- and interspecific polymorphism was observed, and heterozygous markers were identified for the different genotypes to be used for genetic mapping. • These results indicate the utility of the developed primers for comparative mapping studies and the integration of physical and genetic maps.

  12. Development of a molecular method for detection and identification of Xanthomonas campestris pv. viticola Desenvolvimento de um método molecular para detecção e identificação de Xanthomonas campestris pv. viticola

    Directory of Open Access Journals (Sweden)

    Loiselene Carvalho da Trindade

    2007-03-01

    Full Text Available In order to develop a molecular method for detection and identification of Xanthomonas campestris pv. viticola (Xcv the causal agent of grapevine bacterial canker, primers were designed based on the partial sequence of the hrpB gene. Primer pairs Xcv1F/Xcv3R and RST2/Xcv3R, which amplified 243- and 340-bp fragments, respectively, were tested for specificity and sensitivity in detecting DNA from Xcv. Amplification was positive with DNA from 44 Xcv strains and with DNA from four strains of X. campestris pv. mangiferaeindicae and five strains of X. axonopodis pv. passiflorae, with both primer pairs. However, the enzymatic digestion of PCR products could differentiate Xcv strains from the others. None of the primer pairs amplified DNA from grapevine, from 20 strains of nonpathogenic bacteria from grape leaves and 10 strains from six representative genera of plant pathogenic bacteria. Sensitivity of primers Xcv1F/Xcv3R and RST2/Xcv3R was 10 pg and 1 pg of purified Xcv DNA, respectively. Detection limit of primers RST2/Xcv3R was 10(4 CFU/ml, but this limit could be lowered to 10² CFU/ml with a second round of amplification using the internal primer Xcv1F. Presence of Xcv in tissues of grapevine petioles previously inoculated with Xcv could not be detected by PCR using macerated extract added directly in the reaction. However, amplification was positive with the introduction of an agar plating step prior to PCR. Xcv could be detected in 1 µl of the plate wash and from a cell suspension obtained from a single colony. Bacterium identity was confirmed by RFLP analysis of the RST2/Xcv3R amplification products digested with Hae III.Com o objetivo de desenvolver um método molecular para detecção e identificação de Xanthomonas campestris pv. viticola (Xcv, agente causal do cancro bacteriano da videira, oligonucleotídeos (primers foram desenhados com base na seqüência parcial do gene hrpB. As combinações de primers Xcv1F/Xcv3R e RST2/Xcv3R que

  13. Genome sequencing reveals a new lineage associated with lablab bean and genetic exchange between Xanthomonas axonopodis pv. phaseoli and Xanthomonas fuscans subsp. fuscans

    Directory of Open Access Journals (Sweden)

    Valente eAritua

    2015-10-01

    Full Text Available Common bacterial blight is a devastating seed-borne disease of common beans that also occurs on other legume species including lablab and Lima beans. We sequenced and analysed the genomes of 26 isolates of Xanthomonas axonopodis pv. phaseoli and X. fuscans subsp. fuscans, the causative agents of this disease, collected over four decades and six continents. This revealed considerable genetic variation within both taxa, encompassing both single-nucleotide variants and differences in gene content, that could be exploited for tracking pathogen spread. The bacterial isolate from Lima bean fell within the previously described Genetic Lineage 1, along with the pathovar type isolate (NCPPB 3035. The isolates from lablab represent a new, previously unknown genetic lineage closely related to strains of X. axonopodis pv. glycines. Finally, we identified more than 100 genes that appear to have been recently acquired by Xanthomonas axonopodis pv. phaseoli from X. fuscans subsp. fuscans.

  14. Effect of soil pH and amendments with dried fodder rape on mycophagous soil animals and Rhizoctonia stem canker of potato

    NARCIS (Netherlands)

    Lootsma, M.; Scholte, K.

    1998-01-01

    Effects of adding dried rape material to the soil and of soil pH on the ability of mycophagous springtails and nematodes to suppress stem canker on potato, caused by Rhizoctonia solani, were investigated in growth chambers. A bioassay was used with the springtail Folsomia fimetaria and the nematode

  15. Yield and quality responses of citrus (Citrus reticulate) and tea (Podocarpus fleuryi Hickel.) to compound fertilizers

    Institute of Scientific and Technical Information of China (English)

    WANG Rui; SHI Xue-gen; WEI You-zhang; YANG Xiao-e; UOTI Juhani

    2006-01-01

    Experiments were carried out with citrus (Citrus reticulate) and tea (Podocarpus fleuryi Hickel.) to studythe effects of compound fertilizers on their yieldsand quality. In the citrus experiment, application of compound fertilizers increased available P,K and Mg contents in soil but decreased alkali-hydrolyzable N contents in soil and N, P and K contents in leaves. In the tea experiment, application of compound fertilizers increased available P, K and Mg contents in soil and N, P, K and Mg contents in leaves but decreased alkali-hydrolyzable N in soil compared with the urea treatment. Application of compound fertilizers could improve the quality of citrus and tea, increase their yields and enhance their economical profits significantly. Compared with the control, application of compound fertilizers increased citrus yields by 6.31, 12.94 and 17.69 t/ha, and those of tea by 0.51, 0.86 and 1.30 t/ha, respectively. Correspondingly, profits were increased by 21.4% to 61.1% for citrus and by 10.0% to 15.7% for tea.Optimal rates of compound fertilizers were recommended for both crops.

  16. Citrus leprosis virus N: A New Dichorhavirus Causing Citrus Leprosis Disease.

    Science.gov (United States)

    Ramos-González, Pedro Luis; Chabi-Jesus, Camila; Guerra-Peraza, Orlene; Tassi, Aline Daniele; Kitajima, Elliot Watanabe; Harakava, Ricardo; Salaroli, Renato Barbosa; Freitas-Astúa, Juliana

    2017-08-01

    Citrus leprosis (CL) is a viral disease endemic to the Western Hemisphere that produces local necrotic and chlorotic lesions on leaves, branches, and fruit and causes serious yield reduction in citrus orchards. Samples of sweet orange (Citrus × sinensis) trees showing CL symptoms were collected during a survey in noncommercial citrus areas in the southeast region of Brazil in 2013 to 2016. Transmission electron microscopy analyses of foliar lesions confirmed the presence of rod-like viral particles commonly associated with CL in the nucleus and cytoplasm of infected cells. However, every attempt to identify these particles by reverse-transcription polymerase chain reaction tests failed, even though all described primers for the detection of known CL-causing cileviruses and dichorhaviruses were used. Next-generation sequencing of total RNA extracts from three symptomatic samples revealed the genome of distinct, although highly related (>92% nucleotide sequence identity), viruses whose genetic organization is similar to that of dichorhaviruses. The genome sequence of these viruses showed citrus trees and those used for the transmission of one of the characterized isolates to Arabidopsis plants were anatomically recognized as Brevipalpus phoenicis sensu stricto. Molecular and biological features indicate that the identified viruses belong to a new species of CL-associated dichorhavirus, which we propose to call Citrus leprosis N dichorhavirus. Our results, while emphasizing the increasing diversity of viruses causing CL disease, lead to a reevaluation of the nomenclature of those viruses assigned to the genus Dichorhavirus. In this regard, a comprehensive discussion is presented.

  17. Computational identification of citrus microRNAs and target analysis in citrus expressed sequence tags.

    Science.gov (United States)

    Song, C; Jia, Q; Fang, J; Li, F; Wang, C; Zhang, Z

    2010-11-01

    MicroRNAs (miRNAs) are a new family of small RNA molecules found in plants and animals. We developed a comprehensive strategy for identifying new miRNA homologues by mining the repository of available citrus expressed sequence tags (ESTs). By adopting a range of filtering criteria, we identified a total of 38 potential miRNAs--nine, five, nine and 15 miRNAs in Citrus trifoliata (ctr-miRNAs), C. clementina (ccl-miRNAs), C. reticulata (crt-miRNAs) and C. sinensis (csi-miRNAs), respectively--from more than 430,000 EST sequences in citrus. Using the potential miRNA sequences, we conducted a further BLAST search of the mRNA database and found six potential target genes in these citrus species. Eight miRNAs were selected in order to verify their existence in citrus using Northern blotting, and the functions of several miRNAs in miRNA-mediated gene regulation are experimentally suggested. It appears that all these miRNAs regulate expression of their target genes by cleavage, which is the most common situation in gene regulation mediated by plant miRNAs. Our achievement in identifying new miRNAs in citrus provides a powerful incentive for further studies on the important roles of these miRNAs.

  18. Small, stable shuttle vectors for use in Xanthomonas.

    Science.gov (United States)

    DeFeyter, R; Kado, C I; Gabriel, D W

    1990-03-30

    Plasmids from three broad-host-range (bhr) incompatibility groups (Inc) were evaluated for use as cloning vectors in Xanthomonas campestris pv. malvacearum (Xcm), the causal agent of bacterial blight of cotton. The IncP vectors pLAFR3 and pVK102 could not be introduced into Xcm at a significant frequency (less than 1 x 10(-10] and IncQ vectors such as pKT210 were unstable in their maintenance and tended to delete cloned inserts. IncW vectors such as pSa747 also were lost readily from Xcm in the absence of selection pressure. We constructed two plasmids, pUFR027 and a cosmid derivative, pUFR034, which have proven useful as cloning vectors in Xcm and other xanthomonads. They contain the pSa origin of DNA replication, the partition locus parA from the Agrobacterium plasmid pTAR, a neomycin-resistance selection marker, and alacZ alpha cassette with cloning sites. pUFR027 is 9.3 kb, and pUFR034 is 8.7 kb in size. They can be mobilized by conjugation into Xcm at a frequency of approx. 1 x 10(-6) per recipient and are maintained stably (greater than 95% retention over 36 generations without selection pressure) in both broth culture and in planta. The plasmids were introduced and maintained stably in X. citri, and in X. campestris pathovars campestris, citrumelo, vesicatoria and translucens, and were moderately stable in X. phaseoli. No effects of the plasmids on pathogenicity have been observed.

  19. Xanthan production by Xanthomonas campestris using whey permeate medium.

    Science.gov (United States)

    Savvides, A L; Katsifas, E A; Hatzinikolaou, D G; Karagouni, A D

    2012-08-01

    Xanthan gum is a polysaccharide that is widely used as stabilizer and thickener with many industrial applications in food industry. Our aim was to estimate the ability of Xanthomonas campestris ATCC 13951 for the production of xanthan gum by using whey as a growth medium, a by-product of dairy industry. X. campestris ATCC 13951 has been studied in batch cultures using a complex medium for the determination of the optimal concentration of glucose, galactose and lactose. In addition, whey was used under various treatment procedures (de-proteinated, partially hydrolyzed by β-lactamase and partially hydrolyzed and de-proteinated) as culture medium, to study the production of xanthan in a 2 l bioreactor with constant stirring and aeration. A production of 28 g/l was obtained when partially hydrolysed β-lactamase was used, which proved to be one of the highest xanthan gum production reported so far. At the same time, an effort has been made for the control and selection of the most appropriate procedure for the preservation of the strain and its use as inoculant in batch cultures, without loss of its viability and its capability of xanthan gum production. The pre-treatment of whey (whey permeate medium hydrolyzed, WPH) was very important for the production of xanthan by the strain X. campestris ATCC 13951 during batch culture conditions in a 2 l bioreactor. Preservation methods such as lyophilization, cryopreservation at various glycerol solution and temperatures have been examined. The results indicated that the best preservation method for the producing strain X. campestris ATCC 13951 was the lyophilization. Taking into account that whey permeate is a low cost by-product of the dairy industry, the production of xanthan achieved under the studied conditions was considered very promising for industrial application.

  20. Preliminary Studies on Species and Distribution of Citrus Viroids in China

    Institute of Scientific and Technical Information of China (English)

    WANG Xue-feng; ZHOU Chang-yong; TANG Ke-zhi; LAN Jian-qiang; ZHOU Yan; LI Zhon-gan

    2008-01-01

    Citrus viroids are the small but economically important RNA pathogens.For investigating their occurrence and distribution in China,65 viroid samples collected from 8 major citrus cultivated regions were evaluated using one-step or multiplex one-step RT-PCR and biological indexing for specifically detection of Citrus exocortis viroid (CEVd),Citrus bent leaf viroid (CBLVd),Hop stunt viroid (HSVd),Citrus viroid-ⅢI (CVd-Ⅲ) and Citrus viroid-Ⅳ (CVd-Ⅳ).The results showed that there were at least 4 kinds of citrus viroids (CEVd,CBLVd,HSVd,and CVd-Ⅲ) on citrus trees in China.Most of the infected citrus plants harbored more than one viroid species,and two plants were infected with up to 4 citrus viroids.Sweet orange was more frequently infected by viroids than other citrus varieties.It is the preliminary report on the species and distribution of citrus viroids in China.

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

    NARCIS (Netherlands)

    Araujo, W.L.; Marcon, J.; jr. Maccheroni, W.; Elsas, van J.D.; Vuurde, van J.W.L.; Azevedo, de J.L.

    2002-01-01

    Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as

  2. Inoculum sources of Xanthomonas fragariae in strawberry nursery packing houses: presence, viability and transmission

    Science.gov (United States)

    Xanthomonas fragariae causes strawberry angular leaf spot, an important disease in strawberry nursery production. When plants are dug and harvested in the field, they are transported to a “trim shed” where the leaves are removed and the roots are trimmed with table-mounted, stainless steel blades. M...

  3. Biochemical and molecular tools reveal two diverse Xanthomonas groups in bananas

    DEFF Research Database (Denmark)

    Adriko, John; Aritua, V.; Mortensen, Carmen Nieves

    2016-01-01

    strain, while the non-pathogenic xanthomonads isolated from both BXW symptomatic and symptomless bananas clustered with group I xanthomonads. The findings reveal dynamic Xanthomonas populations in bananas, which can easily be misrepresented by only using phenotyping and biochemical tests. A combination...

  4. Molecular characterization of Xanthomonas strains responsible for bacterial leaf spot of tomato in Ethiopia

    Science.gov (United States)

    Bacterial spot of tomato (BST) is a major constraint to tomato production in Ethiopia and many other countries leading to significant crop losses. In the present study, using pathogenicity tests, sensitivity to copper and streptomycin, and multilocus sequence analysis, a diverse group of Xanthomonas...

  5. Digital PCR for detection of citrus pathogens

    Science.gov (United States)

    Citrus trees are often infected with multiple pathogens of economic importance, especially those with insect or mite vectors. Real-time/quantitative PCR (qPCR) has been used for high-throughput detection and relative quantification of pathogens; however, target reference or standards are required. I...

  6. Rheology and composition of processed citrus fiber

    Science.gov (United States)

    While fibrous byproducts are abundant in supply, using them in food products in such a way to not degrade taste or texture can be challenging. Citrus fibers have been shown to have high water holding and viscous properties. However, to better incorporate dried orange pulp into foods, their propert...

  7. Detection of Citrus Trees from Uav Dsms

    Science.gov (United States)

    Ok, A. O.; Ozdarici-Ok, A.

    2017-05-01

    This paper presents an automated approach to detect citrus trees from digitals surface models (DSMs) as a single source. The DSMs in this study are generated from Unmanned Aerial Vehicles (UAVs), and the proposed approach first considers the symmetric nature of the citrus trees, and it computes the orientation-based radial symmetry in an efficient way. The approach also takes into account the local maxima (LM) information to verify the output of the radial symmetry. Our contributions in this study are twofold: (i) Such an integrated approach (symmetry + LM) has not been tested to detect (citrus) trees (in orchards), and (ii) the validity of such an integrated approach has not been experienced for an input, e.g. a single DSM. Experiments are performed on five test patches. The results reveal that our approach is capable of counting most of the citrus trees without manual intervention. Comparison to the state-of-the-art reveals that the proposed approach provides notable detection performance by providing the best balance between precision and recall measures.

  8. New Pseudomonas spp. Are Pathogenic to Citrus.

    Directory of Open Access Journals (Sweden)

    Farid Beiki

    Full Text Available Five putative novel Pseudomonas species shown to be pathogenic to citrus have been characterized in a screening of 126 Pseudomonas strains isolated from diseased citrus leaves and stems in northern Iran. The 126 strains were studied using a polyphasic approach that included phenotypic characterizations and phylogenetic multilocus sequence analysis. The pathogenicity of these strains against 3 cultivars of citrus is demonstrated in greenhouse and field studies. The strains were initially grouped phenotypically and by their partial rpoD gene sequences into 11 coherent groups in the Pseudomonas fluorescens phylogenetic lineage. Fifty-three strains that are representatives of the 11 groups were selected and analyzed by partial sequencing of their 16S rRNA and gyrB genes. The individual and concatenated partial sequences of the three genes were used to construct the corresponding phylogenetic trees. The majority of the strains were identified at the species level: P. lurida (5 strains, P. monteilii (2 strains, P. moraviensis (1 strain, P. orientalis (16 strains, P. simiae (7 strains, P. syringae (46 strains, distributed phylogenetically in at least 5 pathovars, and P. viridiflava (2 strains. This is the first report of pathogenicity on citrus of P. orientalis, P. simiae, P. lurida, P. moraviensis and P. monteilii strains. The remaining 47 strains that could not be identified at the species level are considered representatives of at least 5 putative novel Pseudomonas species that are not yet described.

  9. Founder lines for improved citrus biotechnology

    Science.gov (United States)

    This article discusses the research needed to develop the RMCE strategy and molecular assays for site-specific recombinases as tools for genome manipulation. Explanation of genetic engineering used to generate transgenic citrus plants to exhibit a novel phenotype, but not to contain the recombinase...

  10. Ecology of the Asian citrus pysllid

    Science.gov (United States)

    Host selection by psyllids in general appears to involve taste rather than olfaction. Adults are often less discriminating than nymphs. A priori, there is good reason to doubt that Asian citrus psyllid (ACP) uses a long-distance sex pheromone or that ACP orients to host plant volatiles over large (m...

  11. New Pseudomonas spp. Are Pathogenic to Citrus.

    Science.gov (United States)

    Beiki, Farid; Busquets, Antonio; Gomila, Margarita; Rahimian, Heshmat; Lalucat, Jorge; García-Valdés, Elena

    2016-01-01

    Five putative novel Pseudomonas species shown to be pathogenic to citrus have been characterized in a screening of 126 Pseudomonas strains isolated from diseased citrus leaves and stems in northern Iran. The 126 strains were studied using a polyphasic approach that included phenotypic characterizations and phylogenetic multilocus sequence analysis. The pathogenicity of these strains against 3 cultivars of citrus is demonstrated in greenhouse and field studies. The strains were initially grouped phenotypically and by their partial rpoD gene sequences into 11 coherent groups in the Pseudomonas fluorescens phylogenetic lineage. Fifty-three strains that are representatives of the 11 groups were selected and analyzed by partial sequencing of their 16S rRNA and gyrB genes. The individual and concatenated partial sequences of the three genes were used to construct the corresponding phylogenetic trees. The majority of the strains were identified at the species level: P. lurida (5 strains), P. monteilii (2 strains), P. moraviensis (1 strain), P. orientalis (16 strains), P. simiae (7 strains), P. syringae (46 strains, distributed phylogenetically in at least 5 pathovars), and P. viridiflava (2 strains). This is the first report of pathogenicity on citrus of P. orientalis, P. simiae, P. lurida, P. moraviensis and P. monteilii strains. The remaining 47 strains that could not be identified at the species level are considered representatives of at least 5 putative novel Pseudomonas species that are not yet described.

  12. Quantitative distribution of 'Candidatus Liberibacter asiaticus' in citrus plants with citrus huanglongbing.

    Science.gov (United States)

    Li, Wenbin; Levy, Laurene; Hartung, John S

    2009-02-01

    Citrus huanglongbing (HLB), or greening disease, is strongly associated with any of three nonculturable gram-negative bacteria belonging to 'Candidatus Liberibacter spp.' 'Ca. Liberibacter spp.' are transmitted by citrus psyllids to all commercial cultivars of citrus. The diseases can be lethal to citrus and have recently become widespread in both São Paulo, Brazil, and Florida, United States, the locations of the largest citrus industries in the world. Asiatic HLB, the form of the disease found in Florida, is associated with 'Ca. Liberibacter asiaticus' and is the subject of this report. The nonculturable nature of the pathogen has hampered research and little is known about the distribution of 'Ca. L. asiaticus' in infected trees. In this study, we have used a quantitative polymerase chain reaction assay to systematically quantify the distribution of 'Ca. L. asiaticus' genomes in tissues of six species of citrus either identified in the field during survey efforts in Florida or propagated in a greenhouse in Beltsville, MD. The populations of 'Ca. L. asiaticus' inferred from the distribution of 16S rDNA sequences specific for 'Ca. L. asiaticus' in leaf midribs, leaf blades, and bark samples varied by a factor of 1,000 among samples prepared from the six citrus species tested and by a factor of 100 between two sweet orange trees tested. In naturally infected trees, above-ground portions of the tree averaged 10(10) 'Ca. L. asiaticus' genomes per gram of tissue. Similar levels of 'Ca. L. asiaticus' genomes were observed in some but not all root samples from the same plants. In samples taken from greenhouse-inoculated trees, levels of 'Ca. L. asiaticus' genomes varied systematically from 10(4) genomes/g at the graft inoculation site to 10(10) genomes/g in some leaf petioles. Root samples from these trees also contained 'Ca. L. asiaticus' at 10(7) genomes/g. In symptomatic fruit tissues, 'Ca. L. asiaticus' genomes were also readily detected and quantified. The highest

  13. DNA Barcoding for Efficient Species- and Pathovar-Level Identification of the Quarantine Plant Pathogen Xanthomonas

    Science.gov (United States)

    Tian, Qian; Zhao, Wenjun; Lu, Songyu; Zhu, Shuifang; Li, Shidong

    2016-01-01

    Genus Xanthomonas comprises many economically important plant pathogens that affect a wide range of hosts. Indeed, fourteen Xanthomonas species/pathovars have been regarded as official quarantine bacteria for imports in China. To date, however, a rapid and accurate method capable of identifying all of the quarantine species/pathovars has yet to be developed. In this study, we therefore evaluated the capacity of DNA barcoding as a digital identification method for discriminating quarantine species/pathovars of Xanthomonas. For these analyses, 327 isolates, representing 45 Xanthomonas species/pathovars, as well as five additional species/pathovars from GenBank (50 species/pathovars total), were utilized to test the efficacy of four DNA barcode candidate genes (16S rRNA gene, cpn60, gyrB, and avrBs2). Of these candidate genes, cpn60 displayed the highest rate of PCR amplification and sequencing success. The tree-building (Neighbor-joining), ‘best close match’, and barcode gap methods were subsequently employed to assess the species- and pathovar-level resolution of each gene. Notably, all isolates of each quarantine species/pathovars formed a monophyletic group in the neighbor-joining tree constructed using the cpn60 sequences. Moreover, cpn60 also demonstrated the most satisfactory results in both barcoding gap analysis and the ‘best close match’ test. Thus, compared with the other markers tested, cpn60 proved to be a powerful DNA barcode, providing a reliable and effective means for the species- and pathovar-level identification of the quarantine plant pathogen Xanthomonas. PMID:27861494

  14. Ecological genomics in Xanthomonas: the nature of genetic adaptation with homologous recombination and host shifts.

    Science.gov (United States)

    Huang, Chao-Li; Pu, Pei-Hua; Huang, Hao-Jen; Sung, Huang-Mo; Liaw, Hung-Jiun; Chen, Yi-Min; Chen, Chien-Ming; Huang, Ming-Ban; Osada, Naoki; Gojobori, Takashi; Pai, Tun-Wen; Chen, Yu-Tin; Hwang, Chi-Chuan; Chiang, Tzen-Yuh

    2015-03-15

    Comparative genomics provides insights into the diversification of bacterial species. Bacterial speciation usually takes place with lasting homologous recombination, which not only acts as a cohering force between diverging lineages but brings advantageous alleles favored by natural selection, and results in ecologically distinct species, e.g., frequent host shift in Xanthomonas pathogenic to various plants. Using whole-genome sequences, we examined the genetic divergence in Xanthomonas campestris that infected Brassicaceae, and X. citri, pathogenic to a wider host range. Genetic differentiation between two incipient races of X. citri pv. mangiferaeindicae was attributable to a DNA fragment introduced by phages. In contrast to most portions of the genome that had nearly equivalent levels of genetic divergence between subspecies as a result of the accumulation of point mutations, 10% of the core genome involving with homologous recombination contributed to the diversification in Xanthomonas, as revealed by the correlation between homologous recombination and genomic divergence. Interestingly, 179 genes were under positive selection; 98 (54.7%) of these genes were involved in homologous recombination, indicating that foreign genetic fragments may have caused the adaptive diversification, especially in lineages with nutritional transitions. Homologous recombination may have provided genetic materials for the natural selection, and host shifts likely triggered ecological adaptation in Xanthomonas. To a certain extent, we observed positive selection nevertheless contributed to ecological divergence beyond host shifting. Altogether, mediated with lasting gene flow, species formation in Xanthomonas was likely governed by natural selection that played a key role in helping the deviating populations to explore novel niches (hosts) or respond to environmental cues, subsequently triggering species diversification.

  15. Ecological genomics in Xanthomonas: the nature of genetic adaptation with homologous recombination and host shifts

    KAUST Repository

    Huang, Chao-Li

    2015-03-15

    Background: Comparative genomics provides insights into the diversification of bacterial species. Bacterial speciation usually takes place with lasting homologous recombination, which not only acts as a cohering force between diverging lineages but brings advantageous alleles favored by natural selection, and results in ecologically distinct species, e.g., frequent host shift in Xanthomonas pathogenic to various plants. Results: Using whole-genome sequences, we examined the genetic divergence in Xanthomonas campestris that infected Brassicaceae, and X. citri, pathogenic to a wider host range. Genetic differentiation between two incipient races of X. citri pv. mangiferaeindicae was attributable to a DNA fragment introduced by phages. In contrast to most portions of the genome that had nearly equivalent levels of genetic divergence between subspecies as a result of the accumulation of point mutations, 10% of the core genome involving with homologous recombination contributed to the diversification in Xanthomonas, as revealed by the correlation between homologous recombination and genomic divergence. Interestingly, 179 genes were under positive selection; 98 (54.7%) of these genes were involved in homologous recombination, indicating that foreign genetic fragments may have caused the adaptive diversification, especially in lineages with nutritional transitions. Homologous recombination may have provided genetic materials for the natural selection, and host shifts likely triggered ecological adaptation in Xanthomonas. To a certain extent, we observed positive selection nevertheless contributed to ecological divergence beyond host shifting. Conclusion: Altogether, mediated with lasting gene flow, species formation in Xanthomonas was likely governed by natural selection that played a key role in helping the deviating populations to explore novel niches (hosts) or respond to environmental cues, subsequently triggering species diversification. © Huang et al.

  16. Biochemical and molecular tools reveal two diverse Xanthomonas groups in bananas.

    Science.gov (United States)

    Adriko, J; Aritua, V; Mortensen, C N; Tushemereirwe, W K; Mulondo, A L; Kubiriba, J; Lund, O S

    2016-02-01

    Xanthomonas campestris pv. musacearum (Xcm) causing the banana Xanthomonas wilt (BXW) disease has been the main xanthomonad associated with bananas in East and Central Africa based on phenotypic and biochemical characteristics. However, biochemical methods cannot effectively distinguish between pathogenic and non-pathogenic xanthomonads. In this study, gram-negative and yellow-pigmented mucoid bacteria were isolated from BXW symptomatic and symptomless bananas collected from different parts of Uganda. Biolog, Xcm-specific (GspDm), Xanthomonas vasicola species-specific (NZ085) and Xanthomonas genus-specific (X1623) primers in PCR, and sequencing of ITS region were used to identify and characterize the isolates. Biolog tests revealed several isolates as xanthomonads. The GspDm and NZ085 primers accurately identified three isolates from diseased bananas as Xcm and these were pathogenic when re-inoculated into bananas. DNA from more isolates than those amplified by GspDm and NZ085 primers were amplified by the X1623 primers implying they are xanthomonads, these were however non-pathogenic on bananas. In the 16-23 ITS sequence based phylogeny, the pathogenic bacteria clustered together with the Xcm reference strain, while the non-pathogenic xanthomonads isolated from both BXW symptomatic and symptomless bananas clustered with group I xanthomonads. The findings reveal dynamic Xanthomonas populations in bananas, which can easily be misrepresented by only using phenotyping and biochemical tests. A combination of tools provides the most accurate identity and characterization of these plant associated bacteria. The interactions between the pathogenic and non-pathogenic xanthomonads in bananas may pave way to understanding effect of microbial interactions on BXW disease development and offer clues to biocontrol of Xcm.

  17. Citrus tristeza virus-host interactions

    Directory of Open Access Journals (Sweden)

    William O. Dawson

    2013-05-01

    Full Text Available Citrus tristeza virus (CTV is a phloem-limited virus whose natural host range is restricted to citrus and related species. Although the virus has killed millions of trees, almost destroying whole industries, and continually limits production in many citrus growing areas, most isolates are mild or symptomless in most of their host range. There is little understanding of how the virus causes severe disease in some citrus and none in others. Movement and distribution of CTV differs considerably from that of well-studied viruses of herbaceous plants where movement occurs largely through adjacent cells. In contrast, CTV systemically infects plants mainly by long-distance movement with only limited cell-to-cell movement. The virus is transported through sieve elements and occasionally enters an adjacent companion or phloem parenchyma cell where virus replication occurs. In some plants this is followed by cell-to-cell movement into only a small cluster of adjacent cells, while in others there is no cell-to-cell movement. Different proportions of cells adjacent to sieve elements become infected in different plant species. This appears to be related to how well viral gene products interact with specific hosts. CTV has three genes that are not necessary for infection of most of its hosts, but are needed in different combinations for infection of certain citrus species. These genes apparently were acquired by the virus to extend its host range. Some specific viral gene products have been implicated in symptom induction. Remarkably, the deletion of these genes from the virus genome can induce large increases in stem pitting symptoms. The p23 gene, which is a suppressor of RNA silencing and a regulator of viral RNA synthesis, has been shown to be the cause of seedling yellows symptoms in sour orange. Most isolates of CTV in nature are populations of different strains of CTV. The next frontier of CTV biology is the understanding how the virus variants in

  18. Slight Fermentation with Lactobacillus fermentium Improves the Taste (Sugar:Acid Ratio) of Citrus (Citrus reticulata cv. chachiensis) Juice.

    Science.gov (United States)

    Yu, Yuanshan; Xiao, Gengsheng; Xu, Yujuan; Wu, Jijun; Fu, Manqin; Wen, Jing

    2015-11-01

    The aim of this study was to evaluate the hypothesis that fermentation with Lactobacillus fermentium, which can metabolize citric acid, could be applied in improving the taste (sugar:acid ratio) of citrus juice. During fermentation, the strain of L. fermentium can preferentially utilize citric acid of citrus (Citrus reticulata cv. Chachiensis) juice to support the growth without the consumption of sugar. After 6 h of fermentation with L. fermentium at 30 °C, the sugar:acid ratio of citrus juice increased to 22:1 from 12:1, which resulted in that the hedonic scores of sweetness, acidity and overall acceptability of fermented-pasteurized citrus juice were higher than the unfermented-pasteurized citrus juice. Compared with unfermented-pasteurized citrus juice, the ORAC value and total amino acid showed a reduction, and no significant change (P > 0.05) in the L*, a*, b*, total soluble phenolics and ascorbic acid (Vc) content in the fermented-pasteurized citrus juice was observed as compared with unfermented-pasteurized citrus juice. Hence, slight fermentation with L. fermentium can be used for improving the taste (sugar:acid ratio) of citrus juice with the well retaining of quality.

  19. Complete Genome Sequence of Xanthomonas arboricola pv. juglandis 417, a Copper-Resistant Strain Isolated from Juglans regia L.

    Science.gov (United States)

    Pereira, Ulisses P; Gouran, Hossein; Nascimento, Rafael; Adaskaveg, James E; Goulart, Luiz Ricardo; Dandekar, Abhaya M

    2015-01-01

    Here, we report the complete genome sequence of Xanthomonas arboricola pv. juglandis 417, a copper-resistant strain isolated from a blighted walnut fruit (Juglans regia L. cv. Chandler). The genome consists of a single chromosome (5,218 kb).

  20. Examination of the responses of different genotypes of citrus to huanglongbing (citrus greening) under different conditions.

    Science.gov (United States)

    Folimonova, Svetlana Y; Robertson, Cecile J; Garnsey, Stephen M; Gowda, Siddarame; Dawson, William O

    2009-12-01

    ABSTRACT Citrus Huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide. The causal agent of HLB in Florida is thought to be 'Candidatus Liberibacter asiaticus'. In this work, we examined the responses of 30 different genotypes of citrus to Florida isolates of 'Ca. L. asiaticus' under controlled conditions in the greenhouse or growth room. Although 'Ca. L. asiaticus' was able to multiply in all of the plants, a wide range of responses was observed among different hosts. Based on the symptoms developed and the ability of plants to continue growth, the different genotypes were grouped into four categories: sensitive, which exhibited severe chlorosis on leaves, greatly reduced growth, and eventual death; moderately tolerant, which exhibited some scattered distinct symptoms but little or no growth reduction and no plant death; tolerant, which exhibited very minimal symptoms; and genotypes, which exhibited variable reactions. Interestingly, although 'Ca. L. asiaticus' was unevenly distributed within each particular plant, comparison of titers of the bacterium in different citrus genotypes revealed that most accumulated similar levels of 'Ca. L. asiaticus', demonstrating that there is no strict correlation between bacterial titer and severity of disease. Incubation of infected plants in the growth room with continuous light greatly affected symptoms production by reducing the time before distinctive symptoms developed and significantly increasing severity of chlorosis of leaves of all citrus genotypes. These results provide additional evidence of the correlation between disruption of phloem translocation of carbohydrates during HLB infection and the appearance of chlorotic symptoms in leaves of infected trees. We also examined interaction between 'Ca. L. asiaticus' and Citrus tristeza virus, which usually occurs in trees that become infected with HLB, and found no synergistic effect of the two pathogens. We trust that observations reported here

  1. Effects of citrus limon essential oil (Citrus limon L. on cytomorphometric changes of Candida albicans

    Directory of Open Access Journals (Sweden)

    Rina Prabajati

    2017-03-01

    Full Text Available Background: The most common fungal infection found in oral cavity is oral candidiasis, largely caused by Candida species, particularly Candida albicans (C. albicans. Candida infection can get worse since it is difficult to be treated and resistant with antifungal drugs. Therefore, new drugs and compounds as well as alternative therapies involving natural sources that have antifungal activities have continually been developed. Limonene, β-pinene, and ɣ-terpinene contained in Citrus limon essential oil have been known to have quite good antifungal activities against C. albicans. Purpose: This research aimed to examine and analyze the effects of Citrus limon essential oil on cytomorphometric changes of C. albicans. Method: The research used post test only control group design. Based on the results of the pre-elementary research on antifungal activities of Citrus limon essential oil against C. albicans, Citrus limon essential oil used in this research was on concentrations of 1.56%, 1.37%, 1.17%, 0.98%, and 0.78%. Citrus limon essential oil by C. albicans inoculum and incubated for 24 hours and 48 hours. After the incubation, those C. albicans cells were fixed, dried, and then observed using a scanning electron microscopy. Result: The most effective concentrations of Citrus limon essential oil triggering cytomorphometric changes of Candida albicans were at 1.37% and 1.56% with the incubation period of 48 hours. Conclusion: C. albicans can undergo necrosis process through cytomorphometric changes after the administration of Citrus limon essential oil at concentrations of 1.56% and 1.37% with the incubation period of 48 hours.

  2. INFLUENCE OF SALINITY ON CITRUS: A REVIEW PAPER

    Directory of Open Access Journals (Sweden)

    ADNAN Al-Yassin

    2005-04-01

    Full Text Available Due to the rapid expansion of irrigated agriculture, effi cient use of the limited water resources in arid and semi-arid regions is becoming more and more vital. However, water salinity is a major problem due to its negative infl uence on the yields of many crops. It reduces citrus trees’ growth and causes physiological disorders. Primarily salt-stress lowers net CO2 assimilation, stomatal conductance, and water potential of citrus tree leaves, in addition to accumulation of excessive concentration of Chloride or Sodium in leaves. A great deal of research indicates that citrus have the genetic potential to be salt-sensitive; however inheritance studies in citrus are scarce. In this paper the adverse of effects of salinity on physiological aspects of citrus are reviewed. The review summarizes the prevailing state of knowledge about the responses and tolerance of citrus trees to salinity.

  3. In vitro xanthine oxidase inhibitory activity of leaves, fruits and peel extracts of Citrus aurantium, Citrus limetta and Citrus limon

    Directory of Open Access Journals (Sweden)

    Muthiah PL

    2012-07-01

    Full Text Available Aim of the study: To evaluate the in vitro xanthine oxidase inhibitory activity of the extract of leaves, fruits and peel of Citrus aurantium, Citrus limetta and Citrus limon.   Materials and Methods: Xanthine oxidase inhibitory activity was assayed spectrophotometrically under aerobic conditions and the degree of enzyme inhibition was determined by measuring the increase in absorbance at 295nm associated with uric acid formation.   Results: Among the extracts tested, the C.limetta peel extract exhibited highest potency of xanthine oxidase inhibition (IC50 40.16±0.88μg/ml. This was followed by C.aurantium peel (IC50 51.50±2.05μg/ml, C.limon peel (IC50 64.90±1.24μg/ml, C.aurantium leaf (IC5073.50±1.26μg/ml, C.limetta leaf (IC50 74.83±2.42μg/ml, C.limon leaf (IC50 76.83±2.02μg/ml, C.limetta fruit (IC50 95.16±0.60μg/ml extracts compared with the IC50 value of standard allopurinol was 6.6μg/ml.   Conclusion: Recent findings show that the occurrence of gout is increasing worldwide, possibly due to the changes in dietary habits like intake of food rich in nucleic acids, such as meat, sea foods, etc. Xanthine oxidase inhibitors such as allopurinol is the drug of choice, however it has been observed more side effects.  An alternative to allopurinol is the use of medicinal plants, We thus began our program to look for xanthine oxidase inhibitors of phytochemical origin. In conclusion, the study suggests that the leaves and peel extracts of Citrus aurantium, Citrus limetta and Citrus limon possess xanthine oxidase inhibitory activity that might be helpful in preventing or slowing the progress of gout and related disorders.

  4. Pigment and Virulence Deficiencies Associated with Mutations in the aroE Gene of Xanthomonas oryzae pv. oryzae

    OpenAIRE

    2001-01-01

    Xanthomonadins are yellow, membrane-bound pigments produced by members of the genus Xanthomonas. We identified an ethyl methanesulfonate-induced Xanthomonas oryzae pv. oryzae mutant (BXO65) that is deficient for xanthomonadin production and virulence on rice, as well as auxotrophic for aromatic amino acids (Pig− Vir− Aro−). Reversion analysis indicated that these multiple phenotypes are due to a single mutation. A genomic library of the wild-type strain was used to isolate a 7.0-kb clone that...

  5. Asian Citrus Psyllid RNAi Pathway – RNAi evidence

    OpenAIRE

    Taning, Clauvis N. T.; Eduardo C. Andrade; Hunter, Wayne B.; Olivier Christiaens; Guy Smagghe

    2016-01-01

    Diaphorina citri, known as the Asian citrus psyllid, is an important pest of citrus because it transmits a phloem-limited bacteria strongly implicated in huanglongbing (citrus greening disease). Emerging biotechnologies, such as RNA interference, could provide a new sustainable and environmentally friendly strategy for the management of this pest. In this study, genome and functional analysis were performed to verify whether the RNAi core genes are present in the Asian psyllid genome and if t...

  6. Asian Citrus Psyllid RNAi Pathway – RNAi evidence

    OpenAIRE

    Taning, Clauvis N. T.; Andrade, Eduardo C. de; Hunter, Wayne B.; Christiaens, Olivier; Smagghe, Guy

    2016-01-01

    Diaphorina citri, known as the Asian citrus psyllid, is an important pest of citrus because it transmits a phloem-limited bacteria strongly implicated in huanglongbing (citrus greening disease). Emerging biotechnologies, such as RNA interference, could provide a new sustainable and environmentally friendly strategy for the management of this pest. In this study, genome and functional analysis were performed to verify whether the RNAi core genes are present in the Asian psyllid genome and if t...

  7. Comparison of Genomes of Three Xanthomonas oryzae Bacteriophages

    Directory of Open Access Journals (Sweden)

    Chen Hui-Yi

    2007-11-01

    Full Text Available Abstract Background Xp10 and OP1 are phages of Xanthomonas oryzae pv. oryzae (Xoo, the causative agent of bacterial leaf blight in rice plants, which were isolated in 1967 in Taiwan and in 1954 in Japan, respectively. We recently isolated the Xoo phage Xop411. Results The linear Xop411 genome (44,520 bp, 58 ORFs sequenced here is 147 bp longer than that of Xp10 (60 ORFs and 735 bp longer than that of OP1 (59 ORFs. The G+C contents of OP1 (51% and Xop411 and Xp10 (52% each are less than that of the host (65%. The 9-bp 3'-overhangs (5'-GGACAGTCT-3' in Xop411 and Xp10 are absent from OP1. More of the deduced Xop411 proteins share higher degrees of identity with Xp10 than with OP1 proteins, while the right end of the genomes of Xp10 and OP1, containing all predicted promoters, share stronger homology. Xop411, Xp10, and OP1 contain 8, 7, and 6 freestanding HNH endonuclease genes, respectively. These genes can be classified into five groups depending on their possession of the HNH domain (HNN or HNH type and/or AP2 domain in intact or truncated forms. While the HNN-AP2 type endonuclease genes dispersed in the genome, the HNH type endonuclease genes, each with a unique copy, were located within the same genome context. Mass spectrometry and N-terminal sequencing showed nine Xop411 coat proteins, among which three were identified, six were assigned as coat proteins (4 and conserved phage proteins (2 in Xp10. The major coat protein, in which only the N-terminal methionine is removed, appears to exist in oligomeric forms containing 2 to 6 subunits. The three phages exhibit different patterns of domain duplication in the N-terminus of the tail fiber, which are involved in determination of the host range. Many short repeated sequences are present in and around the duplicated domains. Conclusion Geographical separation may have confined lateral gene transfer among the Xoo phages. The HNN-AP2 type endonucleases were more likely to transfer their genes

  8. Antagonism of Bacillus spp. against Xanthomonas campestris pv. campestris

    Directory of Open Access Journals (Sweden)

    Leila Monteiro

    2005-01-01

    Full Text Available The antagonism of eight Bacillus isolates was investigated against nine strains of Xanthomonas campestris pv. campestris (causal agent of crucifers black rot to assess the role of lipopeptides in this process. Antimicrobial and hemolytic (surfactant activity tests were performed in vitro using agar diffusion methods. Antibiosis and hemolysis were positive for four Bacillus isolates against all X. campestris pv. campestris strains. The correlation observed between antimicrobial and hemolytic activities indicated that lipopeptides were involved in the antibiosis mechanism of the studied antagonists. Fermentation studies were carried out with the isolates that showed highest antimicrobial and hemolytic activities, to follow up growth and production of bioactive and surfactant compounds. Production of bioactive and surfactant compounds was observed during the late growth phase of the Bacillus isolates.Investigação sobre o antagonismo de oito isolados de Bacillus: B. subtilis R14, B. megaterium pv. cerealis RAB7, B. megaterium pv. cerealis C211, B. megaterium C116, Bacillus sp. RAB9, B. cereus C240, Bacillus sp. C11 e B. cereus C210, contra nove linhagens de X. campestris pv. campestris (bactéria responsável pela podridão negra das crucíferas foi realizada para se verificar a participação de lipopeptídeos neste mecanismo. Testes de atividades antimicrobiana e hemolítica (surfactante foram realizados, utilizando-se o método de difusão em ágar. Antibiose e hemólise foram positivas para quatro isolados de Bacillus: R14, RAB7, C116 e C210. A correlação observada entre as atividades antimicrobiana e a hemolítica indica que lipopeptídeos estão envolvidos no mecanismo de antibiose dos isolados investigados. As fermentações foram realizadas com os isolados que demonstraram melhores resultados nos testes de atividades antimicrobiana e hemolítica: R14, RAB7 e C116, para acompanhar o crescimento e a produção de compostos bioativos e

  9. Scientific Opinion on a technical file submitted by the Japanese Authorities to support a derogation request from the EU import requirements for bonsai and topiary trees that are host plants of Anoplophora chinensis

    DEFF Research Database (Denmark)

    Baker, R.; Candresse, T.; Dormannsné Simon, E.

    2010-01-01

    Following a request from the EU Commission, the EFSA PLH Panel conducted a scientific opinion on risk analysis and supporting documents provided by APHIS/USDA in support of the request to remove the Union's plant health import requirement that citrus fruit imported into the EU be sourced from...... groves where, since the beginning of the last cycle of vegetation no symptoms of citrus canker were observed, neither in their vicinities. The PHL Panel concluded that the transmission of Xanthomonas citri subsp. citri (Xcc) on asymptomatic citrus fruit was more likely when the fruit were collected from...... infested than from non-infested areas and groves. Symptomatic fruit carries more Xcc cells than asymptomatic fruit and the packinghouse disinfectant treatments do not achieve the eradication of Xcc. The application of management option 2 (i.e. ‘allow distribution of all types and varieties of commercially...

  10. Citrus tissue culture employing vegetative explants.

    Science.gov (United States)

    Chaturvedi, H C; Singh, S K; Sharma, A K; Agnihotri, S

    2001-11-01

    Citrus being a number one fruit of the world due to its high nutritional value, huge production of fruits and fruit products, the citrus industry may be considered a major fruit industry. Though citrus orchard area in India is comparable to USA, the produce is far less, while its export is nil. Biotechnology has played an outstanding role in boosting the citrus industry, e.g., in Spain, which is now the biggest exporter of citrus fruit with the application of micrografting. Amongst the fruit trees, perhaps the maximum tissue culture research has been done in citrus during the past four decades, however, the results of practical value are meagre. The shortfalls in citrus tissue culture research and some advancements made in this direction along with bright prospects are highlighted, restricting the review to vegetative explants only. Whilst utilization of nucellar embryogenesis is limited to rootstocks, the other aspects, like, regeneration and proliferation of shoot meristems measuring 200 microm in length--a global breakthrough--of two commercially important scion species, Citrus aurantifolia and C. sinensis and an important rootstock, C. limonia, improvement of micrografting technique, cloning of the same two scion species as well as some Indian rootstock species, employing nodal stem segments of mature trees, of immense practical value have been elaborated. A rare phenomenon of shift in the morphogenetic pattern of differentiation from shoot bud differentiation to embryoid formation occurred during the long-term culture of stem callus of C. grandis. Stem callus-regenerated plants of C. aurantifolia, C. sinensis and C. grandis showed variation in their ploidy levels and a somaclonal variant of C. sinensis, which produced seedless fruits was isolated. Tailoring of rooting in microshoots to a tap root-like system by changing the inorganic salt composition of the rooting medium, resulting in 100% transplant success, and germplasm preservation through normal growth

  11. Induction and selection of citrus mutant by gamma-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Jung; Oh, Seung Kyu; Lee, Hyo Yeon [Jeju National University, Jeju (Korea, Republic of)

    2010-09-15

    We have subjected to gamma-irradiation to citrus buds and then grafted onto mature citrus tree. Mutant citrus branch lines have been induced. As a result of first selection, we found the several mutant lines showing interesting phenotypes such as higher sugar content. We have selected several branches showing good qualities such as higher sweetness and/or lower acidity. Some branch lines showed over 13 .deg. Brix sugar content and below 0.9% acidity. Other mutant branch lines showed the changes of shape, size, peel thickness, and fiber contents or distribution of fruits. The results suggest that gamma-irradiation is an effective tool for induction of citrus mutant lines.

  12. Effect of climate change on sporulation of the teleomorphs of Leptosphaeria species causing stem canker of brassicas.

    Science.gov (United States)

    Kaczmarek, Joanna; Kedziora, Andrzej; Brachaczek, Andrzej; Latunde-Dada, Akinwunmi O; Dakowska, Sylwia; Karg, Grzegorz; Jedryczka, Małgorzata

    Leptosphaeria maculans and L. biglobosa are closely related sibling fungal pathogens that cause phoma leaf spotting, stem canker (blackleg) and stem necrosis of oilseed rape (Brassica napus). The disease is distributed worldwide, and it is one of the main causes of considerable decrease in seed yield and quality. Information about the time of ascospore release at a particular location provides important data for decision making in plant protection, thereby enabling fungicides to be used only when necessary and at optimal times and doses. Although the pathogens have been studied very extensively, the effect of climate change on the frequencies and distributions of their aerially dispersed primary inoculum has not been reported to date. We have collected a large dataset of spore counts from Poznan, located in central-west part of Poland, and studied the relationships between climate and the daily concentrations of airborne propagules over a period of 17 years (1998-2014). The average air temperature and precipitation for the time of development of pseudothecia and ascospore release (July-November), increased during the years under study at the rates of 0.1 °C and 6.3 mm per year. The day of the year (DOY) for the first detection of spores, as well as the date with maximum of spores, shifted from 270 to 248 DOY, and from 315 to 265 DOY, respectively. The acceleration of the former parameter by 22 days and the latter by 50 days has great influence on the severity of stem canker of oilseed rape.

  13. Efficacy of heat treatment for the thousand cankers disease vector and pathogen in small black walnut logs.

    Science.gov (United States)

    Mayfield, A E; Fraedrich, S W; Taylor, A; Merten, P; Myers, S W

    2014-02-01

    Thousand cankers disease, caused by the walnut twig beetle (Pityophthorus juglandis Blackman) and an associated fungal pathogen (Geosmithia morbida M. Kolarík, E. Freeland, C. Utley, and N. Tisserat), threatens the health and commercial use of eastern black walnut (Juglans nigra L.), one of the most economically valuable tree species in the United States. Effective phytosanitary measures are needed to reduce the possibility of spreading this insect and pathogen through wood movement. This study evaluated the efficacy of heat treatments and debarking to eliminate P. juglandis and C. morbida in J. nigra logs 4-18 cm in diameter and 30 cm in length. Infested logs were steam heated until various outer sapwood temperatures (60, 65, and 70 degrees C in 2011; 36, 42, 48, 52, and 56 degrees C in 2012) were maintained or exceeded for 30-40 min. In 2011, all heat treatments eliminated G. morbida from the bark, but logs were insufficiently colonized by P. juglandis to draw conclusions about treatment effects on the beetle. Debarking did not ensure elimination of the pathogen from the sapwood surface. In 2012, there was a negative effect of increasing temperature on P. juglandis emergence and G. morbida recovery. G. morbida did not survive in logs exposed to treatments in which minimum temperatures were 48 degrees C or higher, and mean P. juglandis emergence decreased steadily to zero as treatment minimum temperature increased from 36 to 52 degrees C. A minimum outer sapwood temperature of 56 degrees C maintained for 40 min is effective for eliminating the thousand cankers disease vector and pathogen from walnut logs, and the current heat treatment schedule for the emerald ash borer (60 degrees C core temperature for 60 min) is more than adequate for treating P. juglandis and G. morbida in walnut firewood.

  14. Enumerative and binomial sampling plans for citrus mealybug (Homoptera: pseudococcidae) in citrus groves.

    Science.gov (United States)

    Martínez-Ferrer, María Teresa; Ripollés, José Luís; Garcia-Marí, Ferran

    2006-06-01

    The spatial distribution of the citrus mealybug, Planococcus citri (Risso) (Homoptera: Pseudococcidae), was studied in citrus groves in northeastern Spain. Constant precision sampling plans were designed for all developmental stages of citrus mealybug under the fruit calyx, for late stages on fruit, and for females on trunks and main branches; more than 66, 286, and 101 data sets, respectively, were collected from nine commercial fields during 1992-1998. Dispersion parameters were determined using Taylor's power law, giving aggregated spatial patterns for citrus mealybug populations in three locations of the tree sampled. A significant relationship between the number of insects per organ and the percentage of occupied organs was established using either Wilson and Room's binomial model or Kono and Sugino's empirical formula. Constant precision (E = 0.25) sampling plans (i.e., enumerative plans) for estimating mean densities were developed using Green's equation and the two binomial models. For making management decisions, enumerative counts may be less labor-intensive than binomial sampling. Therefore, we recommend enumerative sampling plans for the use in an integrated pest management program in citrus. Required sample sizes for the range of population densities near current management thresholds, in the three plant locations calyx, fruit, and trunk were 50, 110-330, and 30, respectively. Binomial sampling, especially the empirical model, required a higher sample size to achieve equivalent levels of precision.

  15. Phylogenetic Analysis of Citrus tristeza virus Isolates of Wild Type Citrus in China

    Institute of Scientific and Technical Information of China (English)

    YI Long; ZHOU Chang-yong

    2014-01-01

    The genetic variation and phylogenetic relationships of Citrus tristeza virus (CTV) isolates collected from Chinese wild type citrus were analyzed by comparing the sequences of nine genomic regions (p23, p20, p13, p18, p25, p27, POL, HEL and k17) with the CTV isolates of cultivated citrus from different countries. The results showed that the divergence pattern of genomic RNA of the CTV isolates from wild type citrus was similar to that of other isolates from cultivated citrus, the 3´ proximal region was relatively conserved, and the 5´ proximal region had greater variability. The nine genomic regions of CTV isolates analyzed were found to have been under purifying selection in the evolution process. Phylogenetic analysis showed that the eleven Chinese wild CTV isolates were located at different clades and did not relfect their geographical origins, suggesting genetic diversity among the Chinese wild CTV populations. These results will aid in the understanding of molecular evolution of the Chinese CTV populations.

  16. Estimation of Fluoride Concentration of Various Citrus and Non-Citrus Fruits Commonly Consumed and Commercially Available in Mathura City

    Directory of Open Access Journals (Sweden)

    Navin Anand Ingle

    2013-01-01

    Full Text Available Background: Since fluoride is available from various sources, the total ingestion of fluoride by a person should be estimated taking into consideration the fluoride consumed from all the sources including fruits. There are very few epidemiological studies carried out associated with fluoride estimation in fruit samplesand especially in the Indian scenario Objective: To estimate and compare the fluoride concentration of different commercially available citrus and non-citrus fruits in Mathura city. Materials & Method: Fifteen different types of fruits commercially available and consumed by people ofMathura City were collected. Out of the 15 fruit samples 5 were citrus fruits and 10 were non-citrus fruits. The fluoride estimation of fruit samples was done at Central Laboratory,Lucknow. Juices of all 15 fruit samples were prepared, from each sample 10 ml of juice was measured and fluoride testing of each sample was carried out by using Orion 4 star -ion electrode analyzer. The collected data was analyzed using the statistical software program SPSS, version 17. Results: The fluoride concentration in citrus fruits ranged from 0.04ppm (Orange to 0.08 ppm (Tomato while in non-citrus fruits it ranged from 0.04ppm (chikoo to 0.18 ppm (Guava. No significant difference was observed between the mean fluoride concentration of citrus and non citrus fruits. Conclusions: Both citrus and non citrus fruits have fluorides. Guava was found to have the maximumamount of fluoridecontent (0.18 ppm among both the citrus and non citrus fruits.

  17. Anticancer Activity of Key Lime, Citrus aurantifolia

    OpenAIRE

    Nithithep Narang; Wannee Jiraungkoorskul

    2016-01-01

    Citrus aurantifolia (family: Rutaceae) is mainly used in daily consumption, in many cultural cuisines, and in juice production. It is widely used because of its antibacterial, anticancer, antidiabetic, antifungal, anti-hypertensive, anti-inflammation, anti-lipidemia, and antioxidant properties; moreover, it can protect heart, liver, bone, and prevent urinary diseases. Its secondary metabolites are alkaloids, carotenoids, coumarins, essential oils, flavonoids, phenolic acids, and triterpenoids...

  18. Effectiveness of Citrus Fruits on Helicobacter pylori

    Science.gov (United States)

    2017-01-01

    It is known that Helicobacter pylori infection is associated with chronic gastritis, peptic ulcer, and gastric carcinoma. Due to the increased side effects of the treatment regimens and the development of antimicrobial resistance, a number of natural compounds have been tested as potential alternatives. In this review, we will examine the current knowledge on the effect of Citrus fruits and their derivatives against H. pylori, highlighting the remaining outstanding questions on the development of novel therapeutic strategies. PMID:28408943

  19. Huanglongbing Resistance and Tolerance in Citrus

    OpenAIRE

    Stover, E.; McCollum, G.; Driggers, R.; Duan, Y; Shatters, Jr., R. G.; Ritenour, M.; Hall, D.G.; J. Chaparro

    2014-01-01

    Huanglongbing (HLB) is severely impacting Florida citrus. Productivity declines in many HLB-affected genotypes, often with greatly thinned canopies. Fruit size and quality are often adversely affected as the disease advances. HLB was assessed in diverse cultivars in commercial groves with high HLB-incidence. ‘Temple’ had the lowest HLB symptoms and Liberibacter (Las) titer, while ‘Murcott’ and ‘Minneola’ had the highest. The USDA Ft. Pierce, FL farm is managed to reveal genotype responses to ...

  20. Modeling huanglongbing transmission within a citrus tree.

    Science.gov (United States)

    Chiyaka, Christinah; Singer, Burton H; Halbert, Susan E; Morris, J Glenn; van Bruggen, Ariena H C

    2012-07-24

    The citrus disease huanglongbing (HLB), associated with an uncultured bacterial pathogen, is threatening the citrus industry worldwide. A mathematical model of the transmission of HLB between its psyllid vector and citrus host has been developed to characterize the dynamics of the vector and disease development, focusing on the spread of the pathogen from flush to flush (a newly developing cluster of very young leaves on the expanding terminal end of a shoot) within a tree. This approach differs from that of prior models for vector-transmitted plant diseases where the entire plant is the unit of analysis. Dynamics of vector and host populations are simulated realistically as the flush population approaches complete infection. Model analysis indicates that vector activity is essential for initial infection but is not necessary for continued infection because infection can occur from flush to flush through internal movement in the tree. Flush production, within-tree spread, and latent period are the most important parameters influencing HLB development. The model shows that the effect of spraying of psyllids depends on time of initial spraying, frequency, and efficacy of the insecticides. Similarly, effects of removal of symptomatic flush depend on the frequency of removal and the time of initiation of this practice since the start of the epidemic. Within-tree resistance to spread, possibly affected by inherent or induced resistance, is a major factor affecting epidemic development, supporting the notion that alternate routes of transmission besides that by the vector can be important for epidemic development.

  1. Polyembryony in non-apomictic citrus genotypes

    Science.gov (United States)

    Aleza, Pablo; Juárez, José; Ollitrault, Patrick; Navarro, Luis

    2010-01-01

    Background and Aims Adventitious embryony from nucellar cells is the mechanism leading to apomixis in Citrus sp. However, singular cases of polyembryony have been reported in non-apomictic genotypes as a consequence of 2x × 4x hybridizations and in vitro culture of isolated nucelli. The origin of the plants arising from the aforementioned processes remains unclear. Methods The genetic structure (ploidy and allelic constitution with microsatellite markers) of plants obtained from polyembryonic seeds arising from 2x × 4x sexual hybridizations and those regenerated from nucellus culture in vitro was systematically analysed in different non-apomictic citrus genotypes. Histological studies were also conducted to try to identify the initiation process underlying polyembryony. Key Results All plants obtained from the same undeveloped seed in 2x × 4x hybridizations resulted from cleavage of the original zygotic embryo. Also, the plants obtained from in vitro nucellus culture were recovered by somatic embryogenesis from cells that shared the same genotype as the zygotic embryos of the same seed. Conclusions It appears that in non-apomictic citrus genotypes, proembryos or embryogenic cells are formed by cleavage of the zygotic embryos and that the development of these adventitious embryos, normally hampered, can take place in vivo or in vitro as a result of two different mechanisms that prevent the dominance of the initial zygotic embryo. PMID:20675656

  2. Citrus aurantium blossom and preoperative anxiety.

    Science.gov (United States)

    Akhlaghi, Mahmood; Shabanian, Gholamreza; Rafieian-Kopaei, Mahmoud; Parvin, Neda; Saadat, Mitra; Akhlaghi, Mohsen

    2011-01-01

    Reducing anxiety is very important before operation. Preoperative visit and use of premedication are popular methods to achieve this goal, but the role of anxiolytic premedication remains unclear and postoperative side-effects may result from routine premedication. Citrus aurantium is used as an alternative medicine in some countries to treat anxiety, and recently the anxiolytic role of this medicinal plant was established in an animal model study. The aim of this study was to assess the anxiolytic effect of Citrus aurantium blossomon preoperative anxiety. We studied 60 ASA I patients undergoing minor operation. In a randomized double-blind design, two groups of 30 patients received one of the following oral premedication two hours before induction of anesthesia: 1) Citrus aurantium blossom distillate 1mL.kg(-1) (C-group); 2) Saline solution 1mL.kg(-1) as placebo (P-group). Anxiety was measured before and after premedication using the Spielberger state-trait anxiety inventory (STAI-state) and the Amsterdam preoperative anxiety and information scale (APAIS) before operation. After premedication, both the STAI-state and the APAIS scales were decreased in C-group (ppreoperative anxiety before minor operation. Copyright © 2011 Elsevier Editora Ltda. All rights reserved.

  3. Effect of Nigerian citrus (Citrus sinensis Osbeck) honey on ethanol metabolism.

    Science.gov (United States)

    Onyesom, I

    2004-12-01

    The effect of Nigerian citrus (Citrus sinensis Osbeck) honey on ethanol metabolism was tested using 45 consenting individuals in apparent good health and between the ages of 25 and 35 years. The subjects were moderate social drinkers matched in terms of body weight and build. The results obtained showed that on average, honey significantly (p 0.05) reduced the degree of intoxication by 9%. Honey could be a promising anti-intoxicating agent, but its long-term biochemical evaluation, possibly as a complement in the management of alcohol intoxication, deserves further study.

  4. Antibacterial Activity of Cinnamaldehyde and Estragole Extracted from Plant Essential Oils against Pseudomonas syringae pv. actinidiae Causing Bacterial Canker Disease in Kiwifruit

    Science.gov (United States)

    Song, Yu-Rim; Choi, Min-Seon; Choi, Geun-Won; Park, Il-Kwon; Oh, Chang-Sik

    2016-01-01

    Pseudomonas syringae pv. actinidiae (Psa) causes bacterial canker disease in kiwifruit. Antibacterial activity of plant essential oils (PEOs) originating from 49 plant species were tested against Psa by a vapor diffusion and a liquid culture assays. The five PEOs from Pimenta racemosa, P. dioica, Melaleuca linariifolia, M. cajuputii, and Cinnamomum cassia efficiently inhibited Psa growth by either assays. Among their major components, estragole, eugenol, and methyl eugenol showed significant antibacterial activity by only the liquid culture assay, while cinnamaldehyde exhibited antibacterial activity by both assays. The minimum inhibitory concentrations (MICs) of estragole and cinnamaldehyde by the liquid culture assay were 1,250 and 2,500 ppm, respectively. The MIC of cinnamaldehyde by the vapor diffusion assay was 5,000 ppm. Based on the formation of clear zones or the decrease of optical density caused by these compounds, they might kill the bacterial cells and this feature might be useful for managing the bacterial canker disease in kiwifruit. PMID:27493612

  5. Antibacterial Activity of Cinnamaldehyde and Estragole Extracted from Plant Essential Oils against Pseudomonas syringae pv. actinidiae Causing Bacterial Canker Disease in Kiwifruit

    Directory of Open Access Journals (Sweden)

    Yu-Rim Song

    2016-08-01

    Full Text Available Pseudomonas syringae pv. actinidiae (Psa causes bacterial canker disease in kiwifruit. Antibacterial activity of plant essential oils (PEOs originating from 49 plant species were tested against Psa by a vapor diffusion and a liquid culture assays. The five PEOs from Pimenta racemosa, P. dioica, Melaleuca linariifolia, M. cajuputii, and Cinnamomum cassia efficiently inhibited Psa growth by either assays. Among their major components, estragole, eugenol, and methyl eugenol showed significant antibacterial activity by only the liquid culture assay, while cinnamaldehyde exhibited antibacterial activity by both assays. The minimum inhibitory concentrations (MICs of estragole and cinnamaldehyde by the liquid culture assay were 1,250 and 2,500 ppm, respectively. The MIC of cinnamaldehyde by the vapor diffusion assay was 5,000 ppm. Based on the formation of clear zones or the decrease of optical density caused by these compounds, they might kill the bacterial cells and this feature might be useful for managing the bacterial canker disease in kiwifruit.

  6. Xanthomonas populi (ex. Ridé 1958) sp. nov., nom. rev.

    OpenAIRE

    1992-01-01

    Because of an oversight, the name Xanthomonas populi (Ride 1958) Ride and Ride 1978 was not included on the Approved lasts of Bacterial Names and therefore lost its nomenclatural standing. In this paper, the name is revived for application to the same taxon. A description of the taxon is given. Because no type strain was designated in the original publication, a neotype strain is proposed.

  7. Comparative and functional genomic analyses of the pathogenicity of phytopathogen Xanthomonas campestris pv. campestris

    OpenAIRE

    Qian, Wei; Jia, Yantao; Ren, Shuang-Xi; He, Yong-Qiang; Feng, Jia-Xun; Lu, Ling-Feng; Sun, Qihong; Ying, Ge; Tang, Dong-Jie; Tang, Hua; Wu, Wei; Hao, Pei; Wang, Lifeng; Jiang, Bo-Le; Zeng, Shenyan

    2005-01-01

    Xanthomonas campestris pathovar campestris (Xcc) is the causative agent of crucifer black rot disease, which causes severe losses in agricultural yield world-wide. This bacterium is a model organism for studying plant-bacteria interactions. We sequenced the complete genome of Xcc 8004 (5,148,708 bp), which is highly conserved relative to that of Xcc ATCC 33913. Comparative genomics analysis indicated that, in addition to a significant genomic-scale rearrangement cross the replication axis bet...

  8. Production of Hesperetin Glycosides by Xanthomonas campestris and Cyclodextrin Glucanotransferase and Their Anti-allergic Activities

    Directory of Open Access Journals (Sweden)

    Hiroki Hamada

    2010-02-01

    Full Text Available The production of hesperetin glycosides was investigated using glycosylation with Xanthomonas campestris and cyclodextrin glucanotransferase (CGTase. X. campestris glucosylated hesperetin to its 3'-, 5-, and 7-O-glucosides, and CGTase converted hesperetin glucosides into the corresponding maltosides. The resulting 7-O-glucoside and 7-O-maltoside of hesperetin showed inhibitory effects on IgE antibody production and on O2- generation from rat neutrophils.

  9. Identification of xanthans isolated from sugarcane juices obtained from scalded plants infected by Xanthomonas albilineans.

    Science.gov (United States)

    Fontaniella, Blanca; Rodríguez, C W; Piñón, Dolores; Vicente, C; Legaz, María-Estrella

    2002-04-25

    The exudate gum produced by Xanthomonas albilineans, a specific sugarcane pathogen, has been isolated from juices of diseased sugarcane stalks, hydrolyzed with hydrochloric acid, and the hydrolysate analyzed by capillary electrophoresis. Sucrose. cellobiose, mannose, glucose, glucose-1-P and glucuronic acid were identified as the major components of the polysaccharide isolated from diseased stalks. Juices from healthy stalks contained maltose instead of cellobiose. The chemical nature of this polysaccharide is discussed.

  10. Antibacterial Activity of Cinnamaldehyde and Estragole Extracted from Plant Essential Oils against Pseudomonas syringae pv. actinidiae Causing Bacterial Canker Disease in Kiwifruit

    OpenAIRE

    2016-01-01

    Pseudomonas syringae pv. actinidiae (Psa) causes bacterial canker disease in kiwifruit. Antibacterial activity of plant essential oils (PEOs) originating from 49 plant species were tested against Psa by a vapor diffusion and a liquid culture assays. The five PEOs from Pimenta racemosa, P. dioica, Melaleuca linariifolia, M. cajuputii, and Cinnamomum cassia efficiently inhibited Psa growth by either assays. Among their major components, estragole, eugenol, and methyl eugenol showed significant ...

  11. Citrus essential oils: Extraction, authentication and application in food preservation.

    Science.gov (United States)

    Mahato, Neelima; Sharma, Kavita; Koteswararao, Rakoti; Sinha, Mukty; Baral, Ek Raj; Cho, Moo Hwan

    2017-09-28

    Citrus EOs is an economic, eco-friendly and natural alternatives to chemical preservatives and other synthetic antioxidants, such as sodium nitrites, nitrates or benzoates, commonly utilized in food preservation. Citrus based EOs is obtained mainly from the peels of citrus fruits which are largely discarded as wastes and cause environmental problems. The extraction of citrus oils from the waste peels not only saves environment but can be used in various applications including food preservation. The present article presents elaborated viewpoints on the nature and chemical composition of different EOs present in main citrus varieties widely grown across the globe; extraction, characterization and authentication techniques/methods of the citrus EOs; and reviews the recent advances in the application of citrus EOs for the preservation of fruits, vegetables, meat, fish and processed food stuffs. The probable reaction mechanism of the EOs based thin films formation with biodegradable polymers is presented. Other formulation, viz., EOs microencapsulation incorporating biodegradable polymers, nanoemulsion coatings, spray applications and antibacterial action mechanism of the active compounds present in the EOs have been elaborated. Extensive research is required on overcoming the challenges regarding allergies and obtaining safer dosage limits. Shift towards greener technologies indicate optimistic future towards safer utilization of citrus based EOs in food preservation.

  12. Developing cryotherapy to eliminate graft-transmissible pathogens in citrus

    Science.gov (United States)

    This article summarizes research being conducted as part of a project funded by the California Citrus Research Board to develop cryotherapy (freezing buds in liquid nitrogen, and then recovering them) as a viable method for elimination of graft transmissible pathogens from Citrus. There are current...

  13. 21 CFR 74.302 - Citrus Red No. 2.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Citrus Red No. 2. 74.302 Section 74.302 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES SUBJECT TO CERTIFICATION Foods § 74.302 Citrus Red No. 2. (a) Identity. (1) The color...

  14. Characterizing the citrus cultivar Carrizo genome through 454 shotgun sequencing.

    Science.gov (United States)

    Belknap, William R; Wang, Yi; Huo, Naxin; Wu, Jiajie; Rockhold, David R; Gu, Yong Q; Stover, Ed

    2011-12-01

    The citrus cultivar Carrizo is the single most important rootstock to the US citrus industry and has resistance or tolerance to a number of major citrus diseases, including citrus tristeza virus, foot rot, and Huanglongbing (HLB, citrus greening). A Carrizo genomic sequence database providing approximately 3.5×genome coverage (haploid genome size approximately 367 Mb) was populated through 454 GS FLX shotgun sequencing. Analysis of the repetitive DNA fraction indicated a total interspersed repeat fraction of 36.5%. Assembly and characterization of abundant citrus Ty3/gypsy elements revealed a novel type of element containing open reading frames encoding a viral RNA-silencing suppressor protein (RNA binding protein, rbp) and a plant cytokinin riboside 5′-monophosphate phosphoribohydrolase-related protein (LONELY GUY, log). Similar gypsy elements were identified in the Populus trichocarpa genome. Gene-coding region analysis indicated that 24.4% of the nonrepetitive reads contained genic regions. The depth of genome coverage was sufficient to allow accurate assembly of constituent genes, including a putative phloem-expressed gene. The development of the Carrizo database (http://citrus.pw.usda.gov/) will contribute to characterization of agronomically significant loci and provide a publicly available genomic resource to the citrus research community.

  15. Citrus Tristeza Virus on the Island of Crete

    DEFF Research Database (Denmark)

    Shegani, M.; Tsikou, D.; Velimirovic, A.

    2012-01-01

    Over a period of two years, more than 5,000 citrus trees were tested for the presence of Citrus tristeza virus (CTV) on the island of Crete, resulting in thirty eight positives. Comparisons of the relative transcript levels of CTV p23, coat protein (CP), polymerase (POL) and an intergenic (POL/p33...

  16. Development of sparse-seeded mutant kinnow (Citrus reticulata ...

    African Journals Online (AJOL)

    Jane

    2011-10-24

    Oct 24, 2011 ... The mutant was put to the conventional propagation up to mV5, for confirmation of the continuity of ... techniques with fruits such as citrus, grape (Vitis vinifera ... irradiated bud scions were grafted onto Citrus jambhiri rootstock,.

  17. Water and nitrogen use efficiencies in citrus production

    NARCIS (Netherlands)

    Qin, Wei; Assinck, F.B.T.; Heinen, Marius; Oenema, Oene

    2016-01-01

    Water and nitrogen (N) are two key limiting factors for citrus production. Reported effects of water and N inputs on citrus yield, water use efficiency (WUE) and N use efficiency (NUE) vary greatly, mainly due to differences in cultivars, tree age, climate, soil types, and water and N input level

  18. Behavioral assay on Asian citrus psyllid attraction to orange jasmine

    Science.gov (United States)

    The Asian citrus psyllid (ACP) is an important pest because it transmits a bacterium putatively responsible for huanglongbing, a devastating citrus disease. Research on ACP chemical ecology is of interest with respect to identifying attractants and repellents for managing the psyllid. We report on a...

  19. Changes in anthocyanin production during domestication of citrus

    Science.gov (United States)

    Mandarin (C. reticulata), citron (C. medica) and pummelo (C. maxima) are imortant fruit species of the genus Citrus and parents of the interspecific hybrids that constitute the most familiar commercial varities of citrus: sweet orange, sour orange, clementine, lemon lme and grapefruit. Citron and it...

  20. Utilization of founder lines for improved Citrus biotechnology via RMCE

    Science.gov (United States)

    On October 1st 2011 the CRB chose to fund a unique research project, the development of citrus cultivars specifically for genetic engineering (GE). The objective of this research was to develop GE citrus ‘Founder Lines’ containing DNA sequences that will allow the precise insertion of genes for de...

  1. Citrus tristeza virus-host interactions

    Science.gov (United States)

    Dawson, W. O.; Garnsey, S. M.; Tatineni, S.; Folimonova, S. Y.; Harper, S. J.; Gowda, S.

    2013-01-01

    Citrus tristeza virus (CTV) is a phloem-limited virus whose natural host range is restricted to citrus and related species. Although the virus has killed millions of trees, almost destroying whole industries, and continually limits production in many citrus growing areas, most isolates are mild or symptomless in most of their host range. There is little understanding of how the virus causes severe disease in some citrus and none in others. Movement and distribution of CTV differs considerably from that of well-studied viruses of herbaceous plants where movement occurs largely through adjacent cells. In contrast, CTV systemically infects plants mainly by long-distance movement with only limited cell-to-cell movement. The virus is transported through sieve elements and occasionally enters an adjacent companion or phloem parenchyma cell where virus replication occurs. In some plants this is followed by cell-to-cell movement into only a small cluster of adjacent cells, while in others there is no cell-to-cell movement. Different proportions of cells adjacent to sieve elements become infected in different plant species. This appears to be related to how well viral gene products interact with specific hosts. CTV has three genes (p33, p18, and p13) that are not necessary for infection of most of its hosts, but are needed in different combinations for infection of certain citrus species. These genes apparently were acquired by the virus to extend its host range. Some specific viral gene products have been implicated in symptom induction. Remarkably, the deletion of these genes from the virus genome can induce large increases in stem pitting (SP) symptoms. The p23 gene, which is a suppressor of RNA silencing and a regulator of viral RNA synthesis, has been shown to be the cause of seedling yellows (SY) symptoms in sour orange. Most isolates of CTV in nature are populations of different strains of CTV. The next frontier of CTV biology is the understanding how the virus

  2. [Cloning, sequencing and fuctional study of gacA gene from Xanthomonas oryzae pv. oryzicola].

    Science.gov (United States)

    Yang, Wan-feng; Chen, Lei; Liu, Hong-xia; Hu, Bai-shi; Liu, Feng-quan

    2007-04-01

    A gacA homologue, designated gacA(Xooc), was cloned from Xanthomonas oryzae pv. oryzicola (Xooc), a bacterium that causes leaf streak of rice, with degenerated primers by polymerase amplification reaction (PCR). NCBI blast search indicated that GacA(Xooc) had a similar structure to that of other GacA proteins, and had a CheB (Chemotaxis response regulator containing a CheY-like receiver domain)domain. Sequence comparison showed that the gacA(Xooc) was conserved in the Xanthomonas genus. Homology search revealed that the gacA(Xooc) was 99.7% similarities to gacA (AY870457, this lab) of Xanthomonas oryzae pv. oryzae (Xoo). A gacA(Xooc), disruption mutant was successfully generated by a single cross-over event, and confirmed by PCR and Southern blot. But the mutant still had strong pathogenicity,and its virulence was not obviously different from that of wild type strain. The gacA did not globally regulate metabolism in Xooc, which was different from DC3000 of P. syringae pv. tomato, CHAO of P. fluorescens and IC1270 of Serratia plymuthica. Chemotaxis to 0.1% tryptone of the mutants was reduced compared to wild type strain. The results suggest that gacA(X00c) is involved chemotaxis of Xooc. Nevertheless, how gacA to regulate chemotaxis of Xooc, transcription and expression of genes involved in regulation still need to be further studied.

  3. Proposal of Xanthomonas translucens pv. pistaciae pv. nov., pathogenic to pistachio (Pistacia vera).

    Science.gov (United States)

    Giblot-Ducray, Danièle; Marefat, Alireza; Gillings, Michael R; Parkinson, Neil M; Bowman, John P; Ophel-Keller, Kathy; Taylor, Cathy; Facelli, Evelina; Scott, Eileen S

    2009-12-01

    Strains of Xanthomonas translucens have caused dieback in the Australian pistachio industry for the last 15 years. Such pathogenicity to a dicotyledonous woody host contrasts with that of other pathovars of X. translucens, which are characterized by their pathogenicity to monocotyledonous plant families. Further investigations, using DNA-DNA hybridization, gyrB gene sequencing and integron screening, were conducted to confirm the taxonomic status of the X. translucens pathogenic to pistachio. DNA-DNA hybridization provided a clear classification, at the species level, of the pistachio pathogen as a X. translucens. In the gyrB-based phylogeny, strains of the pistachio pathogen clustered among the X. translucens pathovars as two distinct lineages. Integron screening revealed that the cassette arrays of strains of the pistachio pathogen were different from those of other Xanthomonas species, and again distinguished two groups. Together with previously reported pathogenicity data, these results confirm that the pistachio pathogen is a new pathovar of X. translucens and allow hypotheses about its origin. The proposed name is Xanthomonas translucens pv. pistaciae pv. nov.

  4. Expression of sweet pepper Hrap gene in banana enhances resistance to Xanthomonas campestris pv. musacearum.

    Science.gov (United States)

    Tripathi, Leena; Mwaka, Henry; Tripathi, Jaindra Nath; Tushemereirwe, Wilberforce Kateera

    2010-11-01

    Banana Xanthomonas wilt (BXW), caused by the bacterium Xanthomonas campestris pv. musacearum, is the most devastating disease of banana in the Great Lakes region of Africa. The pathogen's rapid spread has threatened the livelihood of millions of Africans who rely on banana fruit for food security and income. The disease is very destructive, infecting all banana varieties, including both East African Highland bananas and exotic types of banana. In the absence of natural host plant resistance among banana cultivars, the constitutive expression of the hypersensitivity response-assisting protein (Hrap) gene from sweet pepper (Capsicum annuum) was evaluated for its ability to confer resistance to BXW. Transgenic lines expressing the Hrap gene under the regulation of the constitutive CaMV35S promoter were generated using embryogenic cell suspensions of two banana cultivars: 'Sukali Ndiizi' and 'Mpologoma'. These lines were characterized by molecular analysis, and were challenged with Xanthomonas campestris pv. musacearum to analyse the efficacy of the Hrap gene against BXW. The majority of transgenic lines (six of eight) expressing Hrap did not show any symptoms of infection after artificial inoculation of potted plants in the screenhouse, whereas control nontransgenic plants showed severe symptoms resulting in complete wilting. This study demonstrates that the constitutive expression of the sweet pepper Hrap gene in banana results in enhanced resistance to BXW. We describe the development of transgenic banana varieties resistant to BXW, which will boost the arsenal available to fight this epidemic disease and save livelihoods in the Great Lakes region of East and Central Africa.

  5. Variation in host and pathogen in the Neonectria/Malus interaction; towards an understanding of the genetic basis of resistance to European canker

    Directory of Open Access Journals (Sweden)

    Antonio Gomez-Cortecero

    2016-09-01

    Full Text Available Apple canker caused by the phytopathogenic fungus Neonectria ditissima is an economically important disease, which has spread in recent years to almost all pome-producing regions of the world. N. ditissima is able to cross-infect a wide range of apple varieties and causes branch and trunk lesions, known as cankers. Most modern apple varieties are susceptible and in extreme cases suffer from high mortality (up to 50% in the early phase of orchard establishment. There is no known race structure of the pathogen and the global level of genetic diversity of the pathogen population is unknown. Resistance breeding is underway in many global breeding programmes, but nevertheless, a total resistance to canker has not yet been demonstrated. Here we present preliminary data from a survey of the phylogenetic relationships between global isolates of N. ditissima which reveals only slight evidence for population structure. In addition we report the results of four rapid screening tests to assess the response to N. ditissima in different apple scion and rootstock varieties, which reveals abundant variation in resistance responses in both cultivar and rootstock material. Further seedling tests show that the segregation patterns of resistance and susceptibility vary widely between crosses. We discuss inconsistencies in test performance with field observations and discuss future research opportunities in this area.

  6. D-PSA-K: A Model for Estimating the Accumulated Potential Damage on Kiwifruit Canes Caused by Bacterial Canker during the Growing and Overwintering Seasons

    Directory of Open Access Journals (Sweden)

    Ki Seok Do

    2016-12-01

    Full Text Available We developed a model, termed D-PSA-K, to estimate the accumulated potential damage on kiwifruit canes caused by bacterial canker during the growing and overwintering seasons. The model consisted of three parts including estimation of the amount of necrotic lesion in a non-frozen environment, the rate of necrosis increase in a freezing environment during the overwintering season, and the amount of necrotic lesion on kiwifruit canes caused by bacterial canker during the overwintering and growing seasons. We evaluated the model’s accuracy by comparing the observed maximum disease incidence on kiwifruit canes against the damage estimated using weather and disease data collected at Wando during 1994–1997 and at Seogwipo during 2014–2015. For the Hayward cultivar, D-PSA-K estimated the accumulated damage as approximately nine times the observed maximum disease incidence. For the Hort16A cultivar, the accumulated damage estimated by D-PSA-K was high when the observed disease incidence was high. D-PSA-K could assist kiwifruit growers in selecting optimal sites for kiwifruit cultivation and establishing improved production plans by predicting the loss in kiwifruit production due to bacterial canker, using past weather or future climate change data.

  7. First report of Pestalotiopsis diospyri causing canker on persimmon trees Primeira ocorrência de Pestalotiopsis diospyri causando cancros em caquizeiros

    Directory of Open Access Journals (Sweden)

    Giselda Alves

    2011-09-01

    Full Text Available During 2006 to 2009 season symptoms of a canker disease were observed on twigs and branches of young and mature persimmon trees (Diospyros kaki L. cv. Fuyu in the States of Santa Catarina and Paraná in the Southern Brazil. The cankers result in severe damage and reduced production. Isolations from the margins of these cankers revealed a genus of Pestalotiopsis. Koch's postulates were confirmed using two isolates of the pathogen which was identified as Pestalotiopsis diospyri.Durante as safras de 2007 a 2009, foram observados sintomas de cancro em ramos e galhos de plantas de caquizeiro (Diospyros kaki L. cv. Fuyu, nos Estados de Santa Catarina e do Paraná, no Sul do Brasil. Os cancros resultavam em danos severos e comprometiam a produção. Após o isolamento da margem dos cancros, detectou-se o gênero Pestalotiopsis em todas as amostras. Os postulados de Koch foram confirmados, utilizando-se dois isolados do patógeno, o qual foi identificado como Pestalotiopsis diospyri.

  8. Mini Review: Innovation technology cultivaion of Citrus Tangerines Borneo Prima in East Kalimantan

    Directory of Open Access Journals (Sweden)

    AFRILIA TRI WIDYAWATI

    2017-03-01

    Full Text Available Abstract. Widyawati AT, Nurbani. 2017. Mini Review: Innovation technology cultivaion of Citrus Tangerines Borneo Prima in East Kalimantan. Pros Sem Nas Masy Biodiv Indon 3: 127-131. The demand for high-value commodities such as oranges continues to increase every year. One of the qualities of orange that can not be met by domestic manufacturers is the color of a citrus peel. Most consumers like citrus orange, like mandarin oranges and other citrus imports. Efforts to reduce the national citrus imports is to improve the productivity and quality of citrus orange in Indonesia. Citrus Tangerines Borneo Prima is one of the featured horticultural commodities in East Kalimantan, which has the advantage of being low lying tangerine with orange rind. It Is indispensable citrus cultivation technique is good and right, so that the citrus plant can develop optimally so that later can produce citrus fruit both in quality and quantity.

  9. Dissipation and residue of forchlorfenuron in citrus fruits.

    Science.gov (United States)

    Chen, Weijun; Jiao, Bining; Su, Xuesu; Zhao, Qiyang; Qin, Dongmei; Wang, Chengqiu

    2013-06-01

    Field trials were carried out in three provinces of China to study the dissipation and residue of forchlorfenuron in citrus fruits. The results had shown that the degradation rate of forchlorfenuron in citrus fruits followed the first-order kinetics equation C = A∙eBt. The half-lives of forchlorfenuron were 15.8-23.0 days, the final residues of forchlorfenuron in pulp were all ≤0.002 mg/kg, and most of the residues were concentrated in the peel. The risk assessment revealed that no significant potential health risk would be induced by forchlorfenuron in citrus fruits. Therefore, it could be safe to apply forchlorfenuron in citrus fruits, and the results of this study could also be regarded as a reference to the setting of maximum residue limit for forchlorfenuron in citrus fruits in China.

  10. Somatic Embryogenesis: Still a Relevant Technique in Citrus Improvement.

    Science.gov (United States)

    Omar, Ahmad A; Dutt, Manjul; Gmitter, Frederick G; Grosser, Jude W

    2016-01-01

    The genus Citrus contains numerous fresh and processed fruit cultivars that are economically important worldwide. New cultivars are needed to battle industry threatening diseases and to create new marketing opportunities. Citrus improvement by conventional methods alone has many limitations that can be overcome by applications of emerging biotechnologies, generally requiring cell to plant regeneration. Many citrus genotypes are amenable to somatic embryogenesis, which became a key regeneration pathway in many experimental approaches to cultivar improvement. This chapter provides a brief history of plant somatic embryogenesis with focus on citrus, followed by a discussion of proven applications in biotechnology-facilitated citrus improvement techniques, such as somatic hybridization, somatic cybridization, genetic transformation, and the exploitation of somaclonal variation. Finally, two important new protocols that feature plant regeneration via somatic embryogenesis are provided: protoplast transformation and Agrobacterium-mediated transformation of embryogenic cell suspension cultures.

  11. Digestion kinetics of carbohydrate fractions of citrus by-products.

    Science.gov (United States)

    Lashkari, Saman; Taghizadeh, Akbar

    2015-01-01

    The present experiment was carried out to determine the digestion kinetics of carbohydrate fractions of citrus by-products. Grapefruit pulp (GP), lemon pulp (LE), lime pulp (LI) and orange pulp (OP) were the test feed. Digestion kinetic of whole citrus by-products and neutral detergent fiber (NDF) fraction and acid detergent fiber (ADF) fractions of citrus by-products were measured using the in vitro gas production technique. Fermentation kinetics of the neutral detergent soluble carbohydrates (NDSC) fraction and hemicelluloses were calculated using a curve subtraction. The fermentation rate of whole was the highest for the LE (p fractions. There was no significant difference among potential gas production (A) volumes of whole test feeds (p fractions of citrus by-products have high potential for degradability. It could also be concluded that carbohydrate fractions of citrus by-products have remarkable difference in digestion kinetics and digestive behavior.

  12. Citrus leaf blotch virus invades meristematic regions in Nicotiana benthamiana and citrus.

    Science.gov (United States)

    Agüero, Jesús; Vives, María Carmen; Velázquez, Karelia; Ruiz-Ruiz, Susana; Juárez, Jose; Navarro, Luis; Moreno, Pedro; Guerri, José

    2013-08-01

    To invade systemically host plants, viruses need to replicate in the infected cells, spread to neighbouring cells through plasmodesmata and move to distal parts of the plant via sieve tubes to start new infection foci. To monitor the infection of Nicotiana benthamiana plants by Citrus leaf blotch virus (CLBV), leaves were agroinoculated with an infectious cDNA clone of the CLBV genomic RNA expressing green fluorescent protein (GFP) under the transcriptional control of a duplicate promoter of the coat protein subgenomic RNA. Fluorescent spots first appeared in agroinfiltrated leaves 11-12 days after infiltration, indicating CLBV replication. Then, after entering the phloem vascular system, CLBV was unloaded in the upper parts of the plant and invaded all tissues, including flower organs and meristems. GFP fluorescence was not visible in citrus plants infected with CLBV-GFP. Therefore, to detect CLBV in meristematic regions, Mexican lime (Citrus aurantifolia) plants were graft inoculated with CLBV, with Citrus tristeza virus (CTV), a virus readily eliminated by shoot-tip grafting in vitro, or with both simultaneously. Although CLBV was detected by hybridization and real-time reverse transcription-polymerase chain reaction (RT-PCR) in 0.2-mm shoot tips in all CLBV-inoculated plants, CTV was not detected. These results explain the difficulty in eliminating CLBV by shoot-tip grafting in vitro. © 2013 BSPP AND JOHN WILEY & SONS LTD.

  13. 77 FR 59709 - Citrus Greening and Asian Citrus Psyllid; Quarantine and Interstate Movement Regulations

    Science.gov (United States)

    2012-10-01

    ...: Effective October 31, 2012. FOR FURTHER INFORMATION CONTACT: Ms. Lynn Evans-Goldner, National Program... Huanglongbing disease of citrus by the international taxonomic community. We are amending the definition to... issued under Sec. 204, Title II, Public Law 106-113, 113 Stat. 1501A-293; sections 301.75-15 and...

  14. 76 FR 78228 - Notice of Request for Extension of Approval of an Information Collection; Citrus Greening and...

    Science.gov (United States)

    2011-12-16

    ... regulations to implement the PPA. Citrus greening, also known as Huanglongbing disease of citrus, is considered to be one of the most serious citrus diseases in the world. Citrus greening is a bacterial disease... the fruit, and can kill trees. Once infected, there is no cure for a tree with citrus greening...

  15. Chemical control of the Asian citrus psyllid and of huanglongbing disease in citrus.

    Science.gov (United States)

    Boina, Dhana Raj; Bloomquist, Jeffrey R

    2015-06-01

    By 2014, huanglongbing (HLB), the most destructive disease of citrus, and its insect vector, the Asian citrus psyllid (ACP), Diaphorina citri (Kuwayama), became established in all major citrus-growing regions of the world, including the United States, with the exception of California. At present, application of insecticides is the most widely followed option for reducing ACP populations, while application of antibiotics for suppressing HLB disease/symptoms is being practiced in some citrus-growing regions. Application of insecticides during the dormant winter season, along with cultivation of HLB-free seedlings and early detection and removal of symptomatic and asymptomatic trees, has been very effective in managing ACP. Area-wide management of ACP by application of insecticides at low volume in large areas of citrus cultivation has been shown to be effective in managing HLB and reducing management costs. As insecticide resistance is a major problem in sustainable management of ACP, rotation/alternation of insecticides with different chemistries and modes of action needs to be followed. Besides control of the insect vector, use of antibiotics has temporarily suppressed the symptoms of HLB in diseased trees. Recent efforts to discover and screen existing as well as new compounds for their antibiotic and antimicrobial activities have identified some promising molecules for HLB control. There is an urgent need to find a sustainable solution to the HLB menace through chemical control of ACP populations and within HLB-infected trees through the judicious use of labeled insecticides (existing and novel chemistries) and antibiotics in area-wide management programs with due consideration to the insecticide resistance problem. © 2014 Society of Chemical Industry.

  16. Analyses of mitogenome sequences revealed that Asian citrus psyllid (Diaphorina citri) from California was related to those from Florida but different from those in Southern China

    Science.gov (United States)

    Asian citrus psyllid (ACP, Diaphorina citri Kuwayama; Hemiptera: Liviidae) transmits “Candidatus Liberibacter asiaticus” (CLas), an unculturable alpha-proteobacterium associated with citrus Huanglongbing (HLB, yellow shoot disease, also called citrus greening disease). HLB is threatening citrus prod...

  17. Green Control Techniques of Diseases and Insect Pests of Citrus%柑橘病虫害绿色防控技术

    Institute of Scientific and Technical Information of China (English)

    李燕辉; 彭昌家; 苟建华; 李鸿韬

    2014-01-01

    Introduced the quarantine control (including the strict implementation of quarantine mea⁃sures,new citrus orchard location need to consult thelocal station of plant protection or plant quarantine station quarantine shall consult opinions,establish the risk of harmful biological monitoring,timely sam⁃pling inspection,do a good job of citrus canker blockade control),agricultural control and prevention (in⁃cluding choosing superior resistant rootstock varieties and virus-free seedling,science and pruning,improv⁃ing ventilation condition,big fruit fly on early removal of tangerine trees fruit,winter, spring gar⁃den,cleaning tillage,conservation and utilization of natural enemies,strengthen the cultivation and man⁃agement,fruit bagging,trunk white-washed,suitable harvest),physical prevention and control (includ⁃ing light trapping,artificial to kill), physical and chemical induced control (including the yellow board trap,sexual trapping agent booby trap,food trapping agent) the scope of application of green control tech⁃niques and various technical and scientific medication and other citrus pests etc.%介绍了检疫控制(包括严格执行检疫措施、新柑橘园选址须征询当地植保植检站或植物检疫站意见、建立检疫性和外来危险性有害生物监测点,及时抽样送检、切实搞好柑橘溃疡病的封锁控制)、农业防控(包括选用优良抗性砧木品种和无病毒苗木、科学修剪,改善通风条件、及早摘除橘树上大实蝇有虫果、冬、春清园、翻耕、保护利用天敌、加强栽培管理、果实套袋、主干刷白、适期采收)、物理防控(包括灯光诱杀、人工捕杀)、理化诱控(包括黄板诱杀、性诱剂诱杀、食诱剂诱杀)和科学用药等柑橘病虫害绿色防控技术及各项技术的适用范围。

  18. Antibacterial activity of Citrus reticulata peel extracts.

    Science.gov (United States)

    Jayaprakasha, G K; Negi, P S; Sikder, S; Rao, L J; Sakariah, K K

    2000-01-01

    Citrus peels were successively extracted with hexane, chloroform and acetone using a soxhlet extractor. The hexane and chloroform extracts were fractionated into alcohol-soluble and alcohol-insoluble fractions. These fractions were tested against different gram positive and gram negative bacteria. The EtOH-soluble fraction was found to be most effective. Fractionation of EtOH-soluble fraction on silica gel column yielded three polymethoxylated flavones, namely desmethylnobiletin, nobiletin and tangeretin. Their structures were confirmed by UV, 1H, 13C NMR and mass spectral studies. The findings indicated a potential of these natural compounds as biopreservatives in food applications.

  19. Citrus huanglongbing: a newly relevant disease presents unprecedented challenges.

    Science.gov (United States)

    Wang, Nian; Trivedi, Pankaj

    2013-07-01

    Citrus huanglongbing (HLB) is one of the oldest citrus diseases and has been known for over a century. HLB is caused by 'Candidatus Liberibacter' spp. that are phloem-limited, fastidious α-proteobacteria and infect hosts in different Kingdoms (i.e., Animalia and Plantae). When compared with well-characterized, cultivatable plant-pathogenic Gram-negative bacteria, the interactions of uncultured insect-vectored plant-pathogenic bacteria, including 'Ca. Liberibacter' spp., with their hosts remain poorly understood. 'Ca. Liberibacter' spp. have been known to cause HLB, which has been rapidly spreading worldwide, resulting in dramatic economic losses. HLB presents an unprecedented challenge to citrus production. In this review, we focus on the most recent research on citrus, 'Candidatus Liberibacter asiaticus', and psyllid interactions, specifically considering the following topics: evolutionary relationships among 'Ca. Liberibacter' spp., genetic diversity, host range, genome analysis, transmission, virulence mechanisms, and the ecological importance of HLB. Currently, no efficient management strategy is available to control HLB, although some promising progress has been made. Further studies are needed to understand citrus, 'Ca. L. asiaticus', and psyllid interactions to design innovative management strategies. Although HLB has been problematic for over a century, we can only win the battle against HLB with a coordinated and deliberate effort by the citrus industry, citrus growers, researchers, legislatures, and governments.

  20. Asian Citrus Psyllid RNAi Pathway – RNAi evidence

    Science.gov (United States)

    Taning, Clauvis N. T.; Andrade, Eduardo C.; Hunter, Wayne B.; Christiaens, Olivier; Smagghe, Guy

    2016-01-01

    Diaphorina citri, known as the Asian citrus psyllid, is an important pest of citrus because it transmits a phloem-limited bacteria strongly implicated in huanglongbing (citrus greening disease). Emerging biotechnologies, such as RNA interference, could provide a new sustainable and environmentally friendly strategy for the management of this pest. In this study, genome and functional analysis were performed to verify whether the RNAi core genes are present in the Asian psyllid genome and if the RNAi machinery could be exploited to develop a management strategy for this pest. Analyses of RNAi-related genes in the Asian citrus psyllid genome showed an absence of sequences encoding R2D2, a dsRNA-binding protein that functions as a cofactor of Dicer-2 in Drosophila. Nevertheless, bioassays using an in Planta System showed that the Asian citrus psyllid was very sensitive to ingested dsRNA, demonstrating a strong RNAi response. A small dose of dsRNA administered through a citrus flush was enough to trigger the RNAi mechanism, causing significant suppression of the targeted transcript, and increased psyllid mortality. This study provides evidence of a functional RNAi machinery, which could be further exploited to develop RNAi based management strategies for the control of the Asian citrus psyllid. PMID:27901078

  1. Two New Complete Genome Sequences Offer Insight into Host and Tissue Specificity of Plant Pathogenic Xanthomonas spp.▿†

    Science.gov (United States)

    Bogdanove, Adam J.; Koebnik, Ralf; Lu, Hong; Furutani, Ayako; Angiuoli, Samuel V.; Patil, Prabhu B.; Van Sluys, Marie-Anne; Ryan, Robert P.; Meyer, Damien F.; Han, Sang-Wook; Aparna, Gudlur; Rajaram, Misha; Delcher, Arthur L.; Phillippy, Adam M.; Puiu, Daniela; Schatz, Michael C.; Shumway, Martin; Sommer, Daniel D.; Trapnell, Cole; Benahmed, Faiza; Dimitrov, George; Madupu, Ramana; Radune, Diana; Sullivan, Steven; Jha, Gopaljee; Ishihara, Hiromichi; Lee, Sang-Won; Pandey, Alok; Sharma, Vikas; Sriariyanun, Malinee; Szurek, Boris; Vera-Cruz, Casiana M.; Dorman, Karin S.; Ronald, Pamela C.; Verdier, Valérie; Dow, J. Maxwell; Sonti, Ramesh V.; Tsuge, Seiji; Brendel, Volker P.; Rabinowicz, Pablo D.; Leach, Jan E.; White, Frank F.; Salzberg, Steven L.

    2011-01-01

    Xanthomonas is a large genus of bacteria that collectively cause disease on more than 300 plant species. The broad host range of the genus contrasts with stringent host and tissue specificity for individual species and pathovars. Whole-genome sequences of Xanthomonas campestris pv. raphani strain 756C and X. oryzae pv. oryzicola strain BLS256, pathogens that infect the mesophyll tissue of the leading models for plant biology, Arabidopsis thaliana and rice, respectively, were determined and provided insight into the genetic determinants of host and tissue specificity. Comparisons were made with genomes of closely related strains that infect the vascular tissue of the same hosts and across a larger collection of complete Xanthomonas genomes. The results suggest a model in which complex sets of adaptations at the level of gene content account for host specificity and subtler adaptations at the level of amino acid or noncoding regulatory nucleotide sequence determine tissue specificity. PMID:21784931

  2. Two new complete genome sequences offer insight into host and tissue specificity of plant pathogenic Xanthomonas spp.

    Science.gov (United States)

    Bogdanove, Adam J; Koebnik, Ralf; Lu, Hong; Furutani, Ayako; Angiuoli, Samuel V; Patil, Prabhu B; Van Sluys, Marie-Anne; Ryan, Robert P; Meyer, Damien F; Han, Sang-Wook; Aparna, Gudlur; Rajaram, Misha; Delcher, Arthur L; Phillippy, Adam M; Puiu, Daniela; Schatz, Michael C; Shumway, Martin; Sommer, Daniel D; Trapnell, Cole; Benahmed, Faiza; Dimitrov, George; Madupu, Ramana; Radune, Diana; Sullivan, Steven; Jha, Gopaljee; Ishihara, Hiromichi; Lee, Sang-Won; Pandey, Alok; Sharma, Vikas; Sriariyanun, Malinee; Szurek, Boris; Vera-Cruz, Casiana M; Dorman, Karin S; Ronald, Pamela C; Verdier, Valérie; Dow, J Maxwell; Sonti, Ramesh V; Tsuge, Seiji; Brendel, Volker P; Rabinowicz, Pablo D; Leach, Jan E; White, Frank F; Salzberg, Steven L

    2011-10-01

    Xanthomonas is a large genus of bacteria that collectively cause disease on more than 300 plant species. The broad host range of the genus contrasts with stringent host and tissue specificity for individual species and pathovars. Whole-genome sequences of Xanthomonas campestris pv. raphani strain 756C and X. oryzae pv. oryzicola strain BLS256, pathogens that infect the mesophyll tissue of the leading models for plant biology, Arabidopsis thaliana and rice, respectively, were determined and provided insight into the genetic determinants of host and tissue specificity. Comparisons were made with genomes of closely related strains that infect the vascular tissue of the same hosts and across a larger collection of complete Xanthomonas genomes. The results suggest a model in which complex sets of adaptations at the level of gene content account for host specificity and subtler adaptations at the level of amino acid or noncoding regulatory nucleotide sequence determine tissue specificity.

  3. The evolution of CMA bands in Citrus and related genera.

    Science.gov (United States)

    e Silva, Ana Emília Barros; Marques, André; dos Santos, Karla G B; Guerra, Marcelo

    2010-06-01

    Most species of Citrus and related genera display a similar karyotype with 2n = 18 and a variable number of terminal heterochromatic blocks positively stained with chromomycin A(3) (CMA(+) bands). Some of these blocks are 45S rDNA sites, whereas others may correspond to the main GC-rich satellite DNA found in several Citrus species. In the present work, the distribution of the 45S rDNA and the main satellite DNA isolated from C. sinensis (CsSat) were investigated by in situ hybridization in seven species of Citrus, two species of closely related genera (Fortunella obovata and Poncirus trifoliata) and four species of the subfamily Aurantioideae, which were less related to Citrus (Atalantia monophylla, Murraya paniculata, Severinia buxifolia, and Triphasia trifolia). In Citrus, Fortunella, and Poncirus, most CMA(+) bands colocalized only with CsSat sites, whereas others colocalized only with rDNA sites. However, some of these species displayed a few CMA(+) bands that colocalized with sites of both probes and other CMA(+) bands that did not colocalized with any of the probes. On the other hand, in the four species less related to Citrus, no CsSat signal was found on chromosomes. On Southern blot, the CsSat probe hybridized with genomic DNA from Citrus, Fortunella, and Poncirus at high stringency only, while under the less stringent conditions, it also hybridized with distantly related species. Therefore, CsSat sequences are the principal component of the heterochromatic blocks of Citrus, Poncirus, and Fortunella, whereas CsSat-like sequences seem to be widespread in the subfamily Aurantioideae. These data further suggest that the variable number of terminal CMA(+) bands observed on chromosomes of Citrus and related genera are probably the consequence of amplification or reduction in the number of CsSat-like sequences distributed on chromosome termini, paralleled by mutation and homogenization events, as proposed by the library hypothesis.

  4. Produção e caracterização de anticorpos policlonais contra Xanthomonas campestris pv. viticola Production and characterization of polyclonal antibodies against Xanthomonas campestris pv. viticola

    OpenAIRE

    2005-01-01

    O objetivo deste trabalho foi a produção de anticorpos policlonais contra Xanthomonas campestris pv. viticola e sua caracterização pelo método Elisa indireto. Os resultados apontaram a qualidade dos anticorpos policlonais produzidos, os quais mostraram-se altamente reativos e específicos para o patovar com potencial para ser empregado no diagnóstico da doença e em programas de certificação.The objective of this work was to produce polyclonal antibodies against Xanthomonas campestris pv. vitic...

  5. Genetic differentiation and spatial structure of Geosmithia morbida, the causal agent of thousand cankers disease in black walnut (Juglans nigra).

    Science.gov (United States)

    Hadziabdic, Denita; Vito, Lisa M; Windham, Mark T; Pscheidt, Jay W; Trigiano, Robert N; Kolarik, Miroslav

    2014-05-01

    The main objectives of this study were to evaluate genetic composition of Geosmithia morbida populations in the native range of black walnut and provide a better understanding regarding demography of the pathogen. The fungus G. morbida, and the walnut twig beetle, Pityophthorus juglandis, have been associated with a disease complex of black walnut (Juglans nigra) known as thousand cankers disease (TCD). The disease is manifested as branch dieback and canopy loss, eventually resulting in tree death. In 2010, the disease was detected in black walnut in Tennessee, and subsequently in Virginia and Pennsylvania in 2011 and North Carolina in 2012. These were the first incidences of TCD east of Colorado, where the disease has been established for more than a decade on indigenous walnut species. A genetic diversity and population structure study of 62 G. morbida isolates from Tennessee, Pennsylvania, North Carolina and Oregon was completed using 15 polymorphic microsatellite loci. The results revealed high haploid genetic diversity among seven G. morbida populations with evidence of gene flow, and significant differentiation among two identified genetic clusters. There was a significant correlation between geographic and genetic distance. Understanding the genetic composition and demography of G. morbida can provide valuable insight into recognizing factors affecting the persistence and spread of an invasive pathogen, disease progression, and future infestation predictions. Overall, these data support the hypotheses of two separate, highly diverse pathogen introductions into the native range of black walnut.

  6. Three genetic groups of the Eucalyptus stem canker pathogen Teratosphaeria zuluensis introduced into Africa from an unknown source.

    Science.gov (United States)

    Jimu, Luke; Chen, ShuaiFei; Wingfield, Michael J; Mwenje, Eddie; Roux, Jolanda

    2016-01-01

    The Eucalyptus stem canker pathogen Teratosphaeria zuluensis was discovered in South Africa in 1988 and it has subsequently been found in several other African countries as well as globally. In this study, the population structure, genetic diversity and evolutionary history of T. z uluensis were analysed using microsatellite markers to gain an enhanced understanding of its movement in Africa. Isolates were collected from several sites in Malawi, Mozambique, Uganda and Zambia. Data obtained were compared with those previously published for a South African population. The data obtained from 334 isolates, amplified across eight microsatellite loci, were used for assignment, differentiation and genetic diversity tests. STRUCTURE analyses, θ st and genetic distances revealed the existence of two clusters, one dominated by isolates from South Africa and the other by isolates from the Zambezi basin including Malawi, Mozambique and Zambia. High levels of admixture were found within and among populations, dominated by the Mulanje population in Malawi. Moderate to low genetic diversity of the populations supports the previously held view that the pathogen was introduced into Africa. The clonal nature of the Ugandan population suggests a very recent introduction, most likely from southern Africa.

  7. Bacterial canker on kiwifruit in Italy: anatomical changes in the wood and in the primary infection sites.

    Science.gov (United States)

    Renzi, Marsilio; Copini, Paul; Taddei, Anna R; Rossetti, Antonio; Gallipoli, Lorenzo; Mazzaglia, Angelo; Balestra, Giorgio M

    2012-09-01

    The bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae is a severe threat to kiwifruit production worldwide. Many aspects of P. syringae pv. actinidiae biology and epidemiology still require in-depth investigation. The infection by and spread of P. syringae pv. actinidiae in xylem and phloem was investigated by carrying out artificial inoculation experiments with histological and dendrochronological analyses of naturally diseased plants in Italy. We found that the bacterium can infect host plants by entering natural openings and lesions. In naturally infected kiwifruit plants, P. syringae pv. actinidiae is present in the lenticels as well as in the dead phloem tissue beneath the lenticels, surrounded by a lesion in the periderm which appears to indicate the importance of lenticels to kiwifruit infection. Biofilm formation was observed outside and inside plants. In cases of advanced stages of P. syringae pv. actinidiae infection, neuroses of the phloem occur, which are followed by cambial dieback and most likely by infection of the xylem. Anatomical changes in wood such as reduced ring width, a drastic reduction in vessel size, and the presence of tyloses were observed within several infected sites. In the field, these changes occur only a year after the first leaf symptoms are observed suggesting a significant time lapse between primary and secondary symptoms. It was possible to study the temporal development of P. syringae pv. actinidiae-induced cambial dieback by applying dendrochronology methods which revealed that cambial dieback occurs only during the growing season.

  8. Nutritional Potential of Citrus Sinensis and Vitis Vinifera Peels

    OpenAIRE

    Uraku, A. J

    2015-01-01

    The nutritional potential of the peels of Citrus sinensis and Vitis vinifera was assessed by determining proximate and mineral composition. Results indicate carbohydeate content of the peels of Citrus sinensis and Vitis vinifera as 61.07% and 71.77% respectively. Other findings are crude fibre, 13.51% and 4.96%, proten, 3.73% and 11.35%, fats, 10.34% and 1.16%, moisture, 9.78% and 6.52% and ash 1.57% and 4.24%, for the Citrus sinensis and Vitis vinifera respectively. Mineral analysis revealed...

  9. Phenology of Asian citrus psyllid (Hemiptera: Liviidae) and associated parasitoids on two species of Citrus, kinnow mandarin and sweet orange, in Punjab Pakistan.

    Science.gov (United States)

    Khan, Shouket Zaman; Arif, Muhammad Jalal; Hoddle, Christina D; Hoddle, Mark S

    2014-10-01

    The population phenology of Asian citrus psyllid, Diaphorina citri Kuwayama, was monitored weekly for 110 wk on two species of Citrus, kinnow mandarin and sweet orange, at two different research sites in Faisalabad, Punjab Pakistan. Citrus flush growth patterns were monitored and natural enemy surveys were conducted weekly. Flush patterns were similar for kinnow and sweet orange. However, flush on sweet orange was consistently more heavily infested with Asian citrus psyllid than kinnow flush; densities of Asian citrus psyllid eggs, nymphs, and adults were higher on sweet orange when compared with kinnow. When measured in terms of mean cumulative insect or Asian citrus psyllid days, eggs, nymphs, and adults were significantly higher on sweet orange than kinnow. Two parasitoids were recorded attacking Asian citrus psyllid nymphs, Tamarixia radiata (Waterston) and Diaphorencyrtus aligarhensis (Shafee, Alam and Agarwal). The dominant parasitoid species attacking Asian citrus psyllid nymphs on kinnow and sweet orange was T. radiata, with parasitism averaging 26%. D. aligarhensis parasitism averaged 17%. Generalist predators such as coccinellids and chrysopids were collected infrequently and were likely not important natural enemies at these study sites. Immature spiders, in particular, salticids and yellow sac spiders, were common and may be important predators of all Asian citrus psyllid life stages. Low year round Asian citrus psyllid densities on kinnow and possibly high summer temperatures, may, in part, contribute to the success of this cultivar in Punjab where Candidatus Liberibacter asiaticus, the putative causative agent of huanglongbing, a debilitating citrus disease, is widespread and vectored by Asian citrus psyllid.

  10. INFLUENCE OF CITRUS LEPROSIS ON THE MINERAL COMPOSITION OF Citrus sinensis LEAVES

    Directory of Open Access Journals (Sweden)

    N. de L. Nogueira

    1996-05-01

    Full Text Available Citrus leprosis is the main viral disease affecting citrus in Brazil. Viral diseases can affect the mineral composition of citrus leaves, inducing mineral deficiencies. The aim of this work was to verify the influence of citrus leprosis on the mineral composition of citrus leaves, cultivar Pera. Orange seedlings were grown in pots containing sterile soil, and kept under greenhouse conditions. When plants had 15 to 20 leaves, they were infested with the mite Brevipalpus phoenicis, the leprosis vector, collected from infected citrus plants. Other plants were not infested, and were used as the control. Ninety days after infestation, all the infested plants presented leprosis lesions. The six upper leaves of each plant were collected and the determination of macro and micro-elements was performed. Leaves from the infected plants showed lower levels of N and higher levels of Ca, S and Fe, as compared to the control (= 0.05. Both treatments presented similar levels of P, K, Mg, Cu,Mn, Zn and B.A leprose dos citros é uma das principais doenças de citros no Brasil. As doenças causadas por vírus podem afetar a composição mineral de folhas de citros, induzindo deficiências minerais. Este trabalho teve como objetivo analisar a influência da leprose dos citros na composição mineral de folhas de citros, cultivar Pera. Seedlings de laranja foram crescidos em vasos contendo solo estéril e mantidos em casa de vegetação. Plantas com 15 a 20 folhas foram infestadas com ácaro da espécie Brevipalpus phoenicis, vetor da leprose dos citros, provenientes de plantas de citros com sintomas da doença. Outras plantas não foram infestadas, e serviram como controle. Após noventa dias, todas as plantas infestadas apresentavam lesões de leprose. Seis folhas da parte superior de cada planta foram coletadas para determinação dos teores de macro e micronutrientes. As folhas das plantas infectadas apresentaram níveis mais baixos de N e mais elevados de Ca, S

  11. Somatic hybridization for citrus rootstock breeding: an effective tool to solve some important issues of the Mediterranean citrus industry.

    Science.gov (United States)

    Dambier, Dominique; Benyahia, Hamid; Pensabene-Bellavia, Giovanni; Aka Kaçar, Yildiz; Froelicher, Yann; Belfalah, Zina; Lhou, Beniken; Handaji, Najat; Printz, Bruno; Morillon, Raphael; Yesiloglu, Turgut; Navarro, Luis; Ollitrault, Patrick

    2011-05-01

    The prevalence of sour orange rootstock in the southern and eastern part of the Mediterranean Basin is presently threatened by the spread of Citrus Tristeza Virus (CTV) and its main vector Toxoptera citricida, combined with abiotic constraints such as drought, salinity and alkalinity. The search for alternative CTV-resistant rootstocks that also withstand the other constraints is now considered an urgent priority for a sustainable citrus industry in the area. Complementary progenitors can be found in citrus germplasm to combine the desired traits, particularly between Poncirus and Citrus genera. The production of somatic hybrids allows cumulating all dominant traits irrespective of their heterozygosity level, and would appear to be an effective way to solve the rootstock challenge facing the Mediterranean citrus industry. This paper presents the results obtained during a regional collaborative effort between five countries, to develop new rootstocks by somatic hybridization. New embryogenic callus lines to be used for somatic hybridization have been created. Protoplast fusions have been performed at CIRAD and IVIA laboratories, focusing on intergeneric combinations. Analysis of ploidy level by flow cytometry and molecular markers confirmed the acquisition of new interesting tetraploid somatic hybrids for six combinations. Diploid cybrids with intergeneric (Citrus × Poncirus) nucleus and C. reticulata or C. aurantifolia mitochondria were also identified for four combinations. The agronomical performance of a pre-existing somatic hybrid between Poncirus trifoliata and Citrus reticulata was validated in calcareous soils in Morocco. Somatic hybridization is now integrated into the breeding programs of the five Mediterranean countries.

  12. IDENTIFICATION OF ANTAGONISTS OF Xanthomonas campestris ISOLATED FROM RHIZOSPHERE ZONE OF BROCCOLI FARM AT KEMBANG MERTA VILLAGE, TABANAN, BALI

    Directory of Open Access Journals (Sweden)

    Nadya Treesna Wulansari

    2015-03-01

    Full Text Available The main objectives of this research were to isolate and identify antagonists of Xanthomonas campestris from rhizosphere zone of broccoli plants. Soil samples were collected from broccoli farm located at Kembang Merta village, Tabanan, Bali. Isolation and identification of the antagonists were conducted at the Laboratory of Microbiology, Udayana University. Two fungal (Trichoderma harzianum and Trichoderma viride and two bacterial (Bacillus sp. and Pseudomonas sp. antagonists potentially to be developed as biocontrol agents of Xanthomonas campestris were successfully identified in this research

  13. Chemical characterization of Xanthan biopolymers synthesized by Xanthomonas campestris pv pruni strains; Caracterizacao quimica de biopolimeros sintetizados por Xanthomonas campestris pv pruni

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Angelita da S.; Vendruscolo, Claire T.; Furlan, Ligia [Universidade Federal de Pelotas, RS (Brazil). Centro de Biotecnologia]. E-mail: angelita@ufpel.tche.br; claire@ufpel.tche.br; ligia@ufpel.tche.br; Galland, Griselda [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Qumica

    2001-07-01

    In this work we describe the characterisation of Xanthan biopolymers synthesized by two Xanthomonas campestris pv pruni strains, in aerobic fermentation. By chromatography on TLC we could notice the presence of Mannose monomer in higher proportion in the 82 strain with relation to the another ones. The viscosity results showed the temperature dependence. The 06 and 82 strains had their viscosity increased whereas for the 87 strain we could observe a reduction with temperature increasing. The {sup 13}C NMR spectrum of 87 strain showed the characteristic signals at approximately 92.8, 70.4 and 61.4 ppm, attributed to C1, C4 and C6 from glucose monomer, with higher intensity. (author)

  14. Transcriptional response of Citrus aurantifolia to infection by Citrus tristeza virus.

    Science.gov (United States)

    Gandía, Mónica; Conesa, Ana; Ancillo, Gema; Gadea, José; Forment, Javier; Pallás, Vicente; Flores, Ricardo; Duran-Vila, Nuria; Moreno, Pedro; Guerri, José

    2007-10-25

    Changes in gene expression of Mexican lime plants in response to infection with a severe (T305) or a mild (T385) isolate of Citrus tristeza virus (CTV) were analyzed using a cDNA microarray containing 12,672 probes to 6875 different citrus genes. Statistically significant (P<0.01) expression changes of 334 genes were detected in response to infection with isolate T305, whereas infection with T385 induced no significant change. Induced genes included 145 without significant similarity with known sequences and 189 that were classified in seven functional categories. Genes related with response to stress and defense were the main category and included 28% of the genes induced. Selected transcription changes detected by microarray analysis were confirmed by quantitative real-time RT-PCR. Changes detected in the transcriptome upon infecting lime with T305 may be associated either with symptom expression, with a strain-specific defense mechanism, or with a general response to stress.

  15. Overexpression of citrus polygalacturonase-inhibiting protein in citrus black rot pathogen Alternaria citri.

    Science.gov (United States)

    Katoh, Hiroshi; Nalumpang, Sarunya; Yamamoto, Hiroyuki; Akimitsu, Kazuya

    2007-05-01

    The rough lemon (Citrus jambhiri) gene encoding polygalacturonase-inhibiting protein (RlemPGIPA) was overexpressed in the pathogenic fungus Alternaria citri. The overexpression mutant AcOPI6 retained the ability to utilize pectin as a sole carbon source, and the overexpression of polygalacturonase-inhibiting protein did not have any effect on the growth of AcOPI6 in potato dextrose and pectin medium. The pathogenicity of AcOPI6 to cause a black rot symptom in citrus fruits was also unchanged. Polygalacturonase-inhibiting protein was secreted together with endopolygalacturonase into culture filtrates of AcOPI6, and oligogalacturonides were digested from polygalacturonic acid by both proteins in the culture filtrates. The reaction mixture containing oligogalacturonides possessed activity for induction of defense-related gene, RlemLOX, in rough lemon leaves.

  16. Genome sequence and rapid evolution of the rice pathogen Xanthomonas oryzae pv. oryzae PXO99A

    Directory of Open Access Journals (Sweden)

    Szurek Boris

    2008-05-01

    Full Text Available Abstract Background Xanthomonas oryzae pv. oryzae causes bacterial blight of rice (Oryza sativa L., a major disease that constrains production of this staple crop in many parts of the world. We report here on the complete genome sequence of strain PXO99A and its comparison to two previously sequenced strains, KACC10331 and MAFF311018, which are highly similar to one another. Results The PXO99A genome is a single circular chromosome of 5,240,075 bp, considerably longer than the genomes of the other strains (4,941,439 bp and 4,940,217 bp, respectively, and it contains 5083 protein-coding genes, including 87 not found in KACC10331 or MAFF311018. PXO99A contains a greater number of virulence-associated transcription activator-like effector genes and has at least ten major chromosomal rearrangements relative to KACC10331 and MAFF311018. PXO99A contains numerous copies of diverse insertion sequence elements, members of which are associated with 7 out of 10 of the major rearrangements. A rapidly-evolving CRISPR (clustered regularly interspersed short palindromic repeats region contains evidence of dozens of phage infections unique to the PXO99A lineage. PXO99A also contains a unique, near-perfect tandem repeat of 212 kilobases close to the replication terminus. Conclusion Our results provide striking evidence of genome plasticity and rapid evolution within Xanthomonas oryzae pv. oryzae. The comparisons point to sources of genomic variation and candidates for strain-specific adaptations of this pathogen that help to explain the extraordinary diversity of Xanthomonas oryzae pv. oryzae genotypes and races that have been isolated from around the world.

  17. Investigation of a Quadruplex-Forming Repeat Sequence Highly Enriched in Xanthomonas and Nostoc sp.

    Science.gov (United States)

    Rehm, Charlotte; Wurmthaler, Lena A; Li, Yuanhao; Frickey, Tancred; Hartig, Jörg S

    2015-01-01

    In prokaryotes simple sequence repeats (SSRs) with unit sizes of 1-5 nucleotides (nt) are causative for phase and antigenic variation. Although an increased abundance of heptameric repeats was noticed in bacteria, reports about SSRs of 6-9 nt are rare. In particular G-rich repeat sequences with the propensity to fold into G-quadruplex (G4) structures have received little attention. In silico analysis of prokaryotic genomes show putative G4 forming sequences to be abundant. This report focuses on a surprisingly enriched G-rich repeat of the type GGGNATC in Xanthomonas and cyanobacteria such as Nostoc. We studied in detail the genomes of Xanthomonas campestris pv. campestris ATCC 33913 (Xcc), Xanthomonas axonopodis pv. citri str. 306 (Xac), and Nostoc sp. strain PCC7120 (Ana). In all three organisms repeats are spread all over the genome with an over-representation in non-coding regions. Extensive variation of the number of repetitive units was observed with repeat numbers ranging from two up to 26 units. However a clear preference for four units was detected. The strong bias for four units coincides with the requirement of four consecutive G-tracts for G4 formation. Evidence for G4 formation of the consensus repeat sequences was found in biophysical studies utilizing CD spectroscopy. The G-rich repeats are preferably located between aligned open reading frames (ORFs) and are under-represented in coding regions or between divergent ORFs. The G-rich repeats are preferentially located within a distance of 50 bp upstream of an ORF on the anti-sense strand or within 50 bp from the stop codon on the sense strand. Analysis of whole transcriptome sequence data showed that the majority of repeat sequences are transcribed. The genetic loci in the vicinity of repeat regions show increased genomic stability. In conclusion, we introduce and characterize a special class of highly abundant and wide-spread quadruplex-forming repeat sequences in bacteria.

  18. The antimicrobial effects of Citrus limonum and Citrus aurantium essential oils on multi-species biofilms

    Directory of Open Access Journals (Sweden)

    Sarah Almeida Coelho Oliveira

    2014-01-01

    Full Text Available The aim of this study was to evaluate the effects of Citrus limonum and Citrus aurantium essential oils (EOs compared to 0.2% chlorhexidine (CHX and 1% sodium hypochlorite (NaOCl on multi-species biofilms formed by Candida albicans, Enterococcus faecalis and Escherichia coli. The biofilms were grown in acrylic disks immersed in broth, inoculated with microbial suspension (106 cells/mL and incubated at 37°C / 48 h. After the biofilms were formed, they were exposed for 5 minutes to the solutions (n = 10: C. aurantium EO, C. limonum EO, 0.2% CHX, 1% NaOCl or sterile saline solution [0.9% sodium chloride (NaCl]. Next, the discs were placed in sterile 0.9% NaCl and sonicated to disperse the biofilms. Tenfold serial dilutions were performed and the aliquots were seeded onto selective agar and incubated at 37°C / 48 h. Next, the number of colony-forming units per milliliter was counted and analyzed statistically (Tukey test, p ≤ 0.05. C. aurantium EO and NaOCl inhibited the growth of all microorganisms in multi-species biofilms. C. limonum EO promoted a 100% reduction of C. albicans and E. coli, and 49.3% of E. faecalis. CHX was less effective against C. albicans and E. coli, yielding a reduction of 68.8% and 86.7%, respectively. However, the reduction of E. faecalis using CHX (81.7% was greater than that obtained using C. limonum EO. Both Citrus limonum and Citrus aurantium EOs are effective in controlling multi-species biofilms; the microbial reductions achieved by EOs were not only similar to those of NaOCl, but even higher than those achieved by CHX, in some cases.

  19. New occupational allergen in citrus farmers: citrus red mite (Panonychus citri).

    Science.gov (United States)

    Kim, Y K; Son, J W; Kim, H Y; Park, H S; Lee, M H; Cho, S H; Min, K U; Kim, Y Y

    1999-02-01

    There have been several reports of occupational allergy to spider mites (Tetranychidae), but no published report has described citrus red mite (CRM, Panonychus citri)-induced occupational asthma confirmed by specific bronchial challenge. The purpose of this study was to evaluate clinical and immunologic characteristics of CRM-induced occupational asthma. We encountered 16 cases of CRM-induced occupational asthma among farmers cultivating citrus fruits. Asthmatic attacks corresponded closely with their work on citrus farms. The mean duration of the latent period was 12.9 (range 7 to 20) years. During their first visit to our clinic, nine patients with FEV1 lower than 70% of predictive value showed reversible airway obstruction after inhalation of bronchodilator, and seven with FEV1 greater than 70% of predictive value showed airway hyperresponsiveness to methacholine. Fifteen of the 16 also complained of recurrent nasal symptoms, which had developed at an earlier time than the asthmatic symptoms. They showed strong positive reactions to CRM extract on skin prick test (A/H ratio > or = 1.0) and had high serum specific IgE antibody against CRM which was detected by ELISA. Skin prick test with common inhalant allergens revealed that 10 had an isolated positive response to CRM with negative results to common inhalant allergens in their environment. The ELISA inhibition tests with CRM demonstrated significant inhibitions by CRM in a dose-dependent manner, while minimal inhibitions were noted by D. pteronyssinus and mugwort allergens. These findings suggest that CRM could induce IgE-mediated bronchoconstriction in exposed workers on citrus farm.

  20. Anti-inflammatory effects of Citrus sinensis L., Citrus paradisi L. and their combinations.

    Science.gov (United States)

    Khan, Rafeeq Alam; Mallick, Neelam; Feroz, Zeeshan

    2016-05-01

    Citrus bioflavonoids embrace a wide group of phenolic compounds effecting the production and scavenging of reactive oxygen species and the processes relating free radical-mediated injury. Keeping in view of the antioxidant and anti-inflammatory properties of Citrus sinensis and Citrus paradisi, present study was undertaken to explore the effects of C. sinensis (orange juice) and C. paradisi (grapefruit juice) at three different doses alone and their two combinations with the objective to examine the effects of these compounds in an experimental model of rat colitis induced by trinitrobenzenesulphonic acid (TNBS). Hence biochemical parameters e.g. myeloperoxidase, alkaline phosphatase, C-reactive protein (CRP) and glutathione were assessed. Data entry and analysis was accomplished by Statistical Package for the Social Sciences version 17 and was presented as mean ± S.E.M with 95% confidence interval. Present result shows that these juices, mainly C. paradisi, may be efficacious for the management of inflammatory bowel disease. In acute colitis model, C. paradise encouraged a decrease in the extension of the lesion escorted by a decrease in the occurrence of diarrhea and reinstatement of the glutathione content. Related effects were produced by the administration of C. sinensis, which also prevented the myeloperoxidase and alkaline phosphatase actions in acute intestinal inflammatory process. The effect of the citrus juices on the inflammatory process may be associated to their antioxidant and anti-inflammatory properties, as revealed in present investigation. The favorable effects exerted were demonstrated both by histological and biochemical changes and were related with a progress in the colonic oxidative status.

  1. Discrimination of citrus tristeza virus (CTV) strains using Mexican ...

    African Journals Online (AJOL)

    Administrator

    2007-02-19

    Feb 19, 2007 ... of the most important factors limiting citrus production worldwide by ... Stem pitting indicates projections of bark in wood, with formation of ... compared to sun orientation, the canopy is divided into eight sub sectors (Aubert ...

  2. The draft genome of sweet orange (Citrus sinensis).

    Science.gov (United States)

    Xu, Qiang; Chen, Ling-Ling; Ruan, Xiaoan; Chen, Dijun; Zhu, Andan; Chen, Chunli; Bertrand, Denis; Jiao, Wen-Biao; Hao, Bao-Hai; Lyon, Matthew P; Chen, Jiongjiong; Gao, Song; Xing, Feng; Lan, Hong; Chang, Ji-Wei; Ge, Xianhong; Lei, Yang; Hu, Qun; Miao, Yin; Wang, Lun; Xiao, Shixin; Biswas, Manosh Kumar; Zeng, Wenfang; Guo, Fei; Cao, Hongbo; Yang, Xiaoming; Xu, Xi-Wen; Cheng, Yun-Jiang; Xu, Juan; Liu, Ji-Hong; Luo, Oscar Junhong; Tang, Zhonghui; Guo, Wen-Wu; Kuang, Hanhui; Zhang, Hong-Yu; Roose, Mikeal L; Nagarajan, Niranjan; Deng, Xiu-Xin; Ruan, Yijun

    2013-01-01

    Oranges are an important nutritional source for human health and have immense economic value. Here we present a comprehensive analysis of the draft genome of sweet orange (Citrus sinensis). The assembled sequence covers 87.3% of the estimated orange genome, which is relatively compact, as 20% is composed of repetitive elements. We predicted 29,445 protein-coding genes, half of which are in the heterozygous state. With additional sequencing of two more citrus species and comparative analyses of seven citrus genomes, we present evidence to suggest that sweet orange originated from a backcross hybrid between pummelo and mandarin. Focused analysis on genes involved in vitamin C metabolism showed that GalUR, encoding the rate-limiting enzyme of the galacturonate pathway, is significantly upregulated in orange fruit, and the recent expansion of this gene family may provide a genomic basis. This draft genome represents a valuable resource for understanding and improving many important citrus traits in the future.

  3. AND Citrus senensis PEEL EXTRACTS ON Aeromonas hydrophila ...

    African Journals Online (AJOL)

    DR. AMINU

    intestinal worms; and as a drastic treatment for ... fractures and the rind decoction with rosemary is ... treat colic, and in India, Citrus senensis peel is used to .... Table 1: Physical characteristics of the peel extract of Annona comosus and C.

  4. Ethno medicinal values of Citrus genus: A review

    Directory of Open Access Journals (Sweden)

    Swapnil Y Chaudhari

    2016-01-01

    Full Text Available Fruits of Citrus genus play an important role as a dietary supplement and therapeutic assent as well since ages. The present review summarizes some such attributes of Citrus genus. Literature review was done through published works to gather information on nutritional and ethnic values, phytochemical and pharmacological properties of Citrus. Information about the plant and phytochemical constituents, pharmacological activities were collected from the published reports. The plant was found to possess significant analgesic, anti-inflammatory, antioxidant, anthelmintic, antibacterial, antifungal, and hypolipidemic properties. They are found to be significant antihyperglycemic, antidiabetic, and hypoglycemic activity. The phytoconstituents which are present in the plant are mainly coumarins and flavonoids which are responsible for the actions. The phytochemical constituents and isolated bioactive compounds of Citrus can be investigated further to develop novel herbal drugs by using reverse pharmacological approaches especially in the treatment of liver diseases, arthritis, malignancies, and other inflammatory diseases.

  5. Citrus phytophtorose in humid subtropical zone of West Georgia

    Directory of Open Access Journals (Sweden)

    Mziuri Gabaidze

    2015-05-01

    Full Text Available Materials about harmfulness of phytophtorose, which is one of the significant disease of citrus, its spread, time of emergency and effective means of its control are given in the article.

  6. Memory boosting effect of Citrus limon, Pomegranate and their combinations

    National Research Council Canada - National Science Library

    Riaz, Azra; Khan, Rafeeq Alam; Algahtani, Hussein A

    2014-01-01

    Memory is greatly influenced by factors like food, stress and quality of sleep, hence present study was designed to evaluate the effect of Citrus limon and Pomegranate juices on memory of mice using...

  7. Growth and nutrient uptake of Citrus rootstock varieties as affected ...

    African Journals Online (AJOL)

    Growth and nutrient uptake of Citrus rootstock varieties as affected poultry manure and NPK fertilizer in Ibadan, Southwestern Nigeria. ... Since plant height and stem diameter determine the quality of rootstock seedlings, poultry manure at 9 ...

  8. Citrus residues isolates improve astaxanthin production by Xanthophyllomyces dendrorhous.

    Science.gov (United States)

    Wu, Wei; Lu, Mingbo; Yu, Longjiang

    2010-01-01

    The wild strain and two astaxanthin-overproducing mutant strains, W618 and GNG274, of Xanthophyllomyces dendrorhous were analyzed in order to assess their ability to grow and synthesize astaxanthin in a minimal medium containing (per liter): 2 g KH2PO4, 0.5 g MgSO4, 2 g KNO3, and 1 g yeast extract, and supplemented with citrus residues isolates as a carbon source (citrus medium). The selected strain W618 was evaluated under various contents of citrus juice. At the content of 20% (v/v), the highest astaxanthin production reached 22.63 mg L(-1), which was two-fold more than that observed in yeast malt medium. Addition of 8% (v/v) n-hexadecane to the citrus medium was found to be optimal, increasing the astaxanthin yield by 21.7%.

  9. 2004 SWFWMD Citrus County Bare-Earth Lidar Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This metadata record describes the ortho & LIDAR mapping of Citrus County, FL. The mapping consists of LIDAR data collection, contour generation, and production...

  10. Complete Genome Sequences of Lytic Bacteriophages of Xanthomonas arboricola pv. juglandis.

    Science.gov (United States)

    Retamales, Julio; Vasquez, Ignacio; Santos, Leonardo; Segovia, Cristopher; Ayala, Manuel; Alvarado, Romina; Nuñez, Pablo; Santander, Javier

    2016-06-02

    Three bacteriophages, f20-Xaj, f29-Xaj, and f30-Xaj, with lytic activity against Xanthomonas arboricola pv. juglandis were isolated from walnut trees (VIII Bío Bío Region, Chile). These lytic bacteriophages have double-stranded DNA (dsDNA) genomes of 43,851 bp, 41,865 bp, and 44,262 bp, respectively. These are the first described bacteriophages with lytic activity against X. arboricola pv. juglandis that can be utilized as biocontrol agents.

  11. Limpeza clonal de mudas de videira infectadas por Xanthomonas campestris pv. viticola

    OpenAIRE

    2013-01-01

    O cancro bacteriano da videira é causado por Xanthomonas campestris pv. viticola (Xcv). Visando à limpeza clonal de mudas de 'Red Globe', foram estudados: tamanho ideal de ápices e gemas axilares para cultivo em meio de Galzy modificado (MGM); efeito da termoterapia (38ºC/30 dias); e ação de antibióticos na eliminação de Xcv em videiras infectadas. Os percentuais de contaminação por Xcv e de regeneração foram analisados, e as plantas obtidas foram indexadas em meio ágar nutritivo-dextrose-ext...

  12. Identificação de potenciais plantas hospedeiras alternativas de Xanthomonas campestris pv. Viticola.

    OpenAIRE

    2014-01-01

    Este estudo teve como objetivo identificar possíveis hospedeiras alternativas de Xanthomonas campestris pv. viticola (Xcv), visando a fornecer subsídios para o manejo do cancro bacteriano da videira. Vinte e seis espécies vegetais foram inoculadas artificialmente com o isolado Xcv3 e mantidas em condições de casa de vegetação, sendo avaliada a evolução sintomatológica da doença, como manchas necróticas angulares e lesões nas nervuras. O Xcv3 foi reisolado a partir de cada hospedeiro alternati...

  13. Diagnose molecular do cancro bacteriano da videira causado por Xanthomonas campestris pv. viticola

    OpenAIRE

    2009-01-01

    A bactéria Xanthomonas campestris pv. viticola (Nayudu) Dye, agente do cancro bacteriano da videira, foi relatada pela primeira vez nas áreas irrigadas do Submédio do Vale São Francisco em Petrolina, Pernambuco, em 1998. A doença também foi identificada em Juazeiro, Bahia, e posteriormente no Piauí, no Ceará, Roraima e Goiás. O uso de material propagativo livre do patógeno tornou-se uma preocupação, uma vez que a ocorrência da bacteriose ainda esta restrita a essas regiões no p...

  14. Meio semi-seletivo para isolamento de Xanthomonas campestris pv. viticola

    OpenAIRE

    2006-01-01

    O cancro bacteriano causado por Xanthomonas campestris pv. viticola é a fitobacteriose mais importante da videira no Submédio São Francisco. O isolamento de X. campestris pv. viticola de tecidos vegetais infectados é dificultado pela presença de contaminantes bacterianos, entre os quais Microbacterium barkeri. Objetivando-se a formulação de meio de cultura semi-seletivo, 22 isolados de X. campestris pv. viticola foram testados com relação a 30 antibióticos. O meio semi-seletivo NYDAM (extrato...

  15. Sobrevivência de Xanthomonas campestris pv. viticola em tecido infectado de videira.

    OpenAIRE

    2012-01-01

    Tecidos de plantas infectados constituem uma importante fonte de inóculo primário para fitobacterioses. O objetivo deste trabalho foi investigar a sobrevivência de Xanthomonas campestris pv. viticola (Xcv), agente do cancro bacteriano da videira, em tecidos infectados na superfície do solo e durante a compostagem de restos de poda. Mudas de videira 'Festival' foram inoculadas com mutante resistente à rifampicina Xcv2Rif e mantidas em casa de vegetação até apresentarem alta severidade da doenç...

  16. Gluconacetobacter diazotrophicus, a sugar cane endosymbiont, produces a bacteriocin against Xanthomonas albilineans, a sugar cane pathogen.

    Science.gov (United States)

    Piñón, Dolores; Casas, Mario; Blanch, María; Fontaniella, Blanca; Blanco, Yolanda; Vicente, Carlos; Solas, María-Teresa; Legaz, María-Estrella

    2002-01-01

    Gluconacetobacter diazotrophicus in liquid culture secretes proteins into the medium. Both medium containing Gluconacetobacter protein and a solution of this protein after acetone precipitation appeared to inhibit the growth of Xanthomonas albilineans in solid culture. This apparent inhibition of bacterial growth has, in fact, been revealed to be lysis of bacterial cells, as demonstrated by transmission electron microscopy. Fractionation of the Gluconacetobacter protein mixture in size-exclusion chromatography reveals a main fraction with lysozyme-like activity which produces lysis of both living bacteria and isolated cell walls.

  17. 复方苯佐卡因凝胶治疗豚鼠口腔溃疡的实验研究%Effects of Benzocaine compound gel on oral canker sore in guinea pigs

    Institute of Scientific and Technical Information of China (English)

    韦宝伟; 刘布鸣; 陈力力; 刘元; 姚树汉

    2011-01-01

    Objective: To compare the effects of benzocaine compound gel ( Gel) and its original product " Orajel? Mouth-Aid " ( OMA ) in the treatment of oral canker sore in guinea pigs. Methods: Oral canker sore models were induced by acetic acid, slaphylo-coccus epidermidis and Candida alhicans respectively in guinea pigs. The canker sore was treated by Gel and OMA at various dosed respectively. The treatment effects were analysed by the canker sore area change before and after treatment. Results; Cel and OMA showed similar effectiveness and dose-dependent effects in the treatment of canker sore in guinea pigs. Conclusion; Benzocain gel and OMA are effective in promoting the healing of oral canker sore.%目的:对比仿制药复方苯佐卡因凝胶(以下简称凝胶)与其被仿品(美国非处方药品“Orajel(R)Mouth-Aid,OMA)”对实验性口腔溃疡治疗作用.方法:采用醋酸、细菌或真菌诱发豚鼠口腔溃疡模型观察药物抗口腔溃疡作用.结果:局部给药,凝胶和OMA均能显著促进醋酸、细菌或真菌诱发的豚鼠口腔溃疡愈合,均具有剂量依赖性.结论:凝腔和OMA均具有促进口腔溃疡愈合作用,耐药作片强度相当.

  18. Agrobacterium-mediated transformation of Citrus sinensis and Citrus limonia epicotyl segments

    Directory of Open Access Journals (Sweden)

    Almeida Weliton Antonio Bastos de

    2003-01-01

    Full Text Available Genetic transformation allows the release of improved cultivars with desirable characteristics in a shorter period of time and therefore may be useful in citrus breeding programs. The objective of this research was to establish a protocol for genetic transformation of Valencia and Natal sweet oranges (Citrus sinensis L. Osbeck and Rangpur lime (Citrus limonia L. Osbeck. Epicotyl segments of germinated in vitro plantlets (three weeks in darkness and two weeks in a 16-h photoperiod were used as explants. These were co-cultivated with Agrobacterium tumefaciens strain EHA-105 and different experiments were done to evaluate the transformation efficiency: explants were co-cultivated with Agrobacterium for one, three or five days; explants were incubated with Agrobacterium suspension for 5, 10, 20 or 40 minutes; co-cultivation medium was supplemented with acetosyringone at 0, 100 or 200 mmol L-1; Explants ends had a longitudinal terminal incision (2-3 mm; co-cultivation temperatures of 19, 23 or 27degreesC were imposed. The experimental design was completely randomized in all experiments with five replications, each consisted of a Petri dish (100 x 15 mm with 30 explants and resulted in a total of 150 explants per treatment. Longitudinal terminal incision in the explant ends did not improve shoot regeneration. However, transgenic plants of all three cultivars were confirmed from explants that had been subjected to inoculation time of 20 minutes, co-culture of three days at 23-27degreesC, in the absence of acetosyringone.

  19. Citrus bergamia essential oil: from basic research to clinical application

    OpenAIRE

    Michele eNavarra; Carmen eMannucci; Marisa eDelbò; Gioacchino eCalapai

    2015-01-01

    Citrus bergamia Risso et Poiteau, also known as Bergamot, is a plant belonging to the Rutaceae family, defined as a hybrid of bitter orange and lemon. It is an endemic plant of the Calabria region (Italy). Bergamot fruit is primarily used for the extraction of its essential oil (bergamot essential oil: BEO), employed in perfume, cosmetics, food and confections.The aim of this review was to collect recent data from the literature on Citrus bergamia essential oil and, through a critical analysi...

  20. ISOLATION OF A FLAVONOID FROM THE ROOTS OF CITRUS SINENSIS

    Directory of Open Access Journals (Sweden)

    JAVED INTEKHAB

    2009-01-01

    Full Text Available Citrus sinensis is native to Asia and throughout the Pacific and warm areas of the world. The ethyl acetate extract of the roots of Citrus sinensis yielded a flavonoid. The compound was characterizedas 5, 8-dihydroxy-6, 7, 4′-trimethoxyflavone on the basis of UV, I.R, mass and N.M.R (1H, 13C spectral studies. We believe this is the first report describing the isolation of flavonoid from thisplant.

  1. Citrus growers vary in their adoption of biological control

    OpenAIRE

    Grogan, Kelly A.; Goodhue, Rachael E.

    2012-01-01

    In a spring 2010 survey, we investigated the characteristics that influenced whether California growers controlled major citrus pests with beneficial insects. We also performed statistical analysis of growers' reliance on Aphytus melinus, a predatory wasp, to control California red scale. The survey results suggest that growers with greater citrus acreage and more education are more likely to use biological control. Marketing outlets, ethnicity and primary information sources also influenced ...

  2. Citrus pectin: structure and application in acid dairy drinks

    OpenAIRE

    Tanhatan Naseri, Abrisham; Thibault, Jean-François

    2008-01-01

    Pectin, a plant cell wall polysaccharide, is mainly used in food industries for its gelling and stabilizing properties. In industrial applications, pectin is usually widely extracted from citrus peels, and in some intances, apple pomace is also used. Lime and lemon are the preferred citrus species used in the extraction of pectin, while orange and grapefruit are used less often. In the food industry, pectin is widely employed in the production of jams and jellies, confectionary products a...

  3. Essential Oils from the Malaysian Citrus (Rutaceae) Medicinal Plants

    OpenAIRE

    Siti Nur Atiqah Md Othman; Muhammad Aizam Hassan; Lutfun Nahar; Norazah Basar; Shajarahtunnur Jamil; Sarker,Satyajit D.

    2016-01-01

    This review article appraises the extraction methods, compositions, and bioactivities of the essential oils from the Citrus species (family: Rutaceae) endemic to Malaysia including C. aurantifolia, C. grandis, C. hystrix, and C. microcarpa. Generally, the fresh peels and leaves of the Citrus species were extracted using different methods such as steam and water distillation, Likens-Nikerson extraction, solvent extraction, and headspace solid-phase micro-extraction (HS-SPME). Most of the Citru...

  4. 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. Copyright © 2014. Published by Elsevier B.V.

  5. Physicochemical Characteristics of Citrus Seed Oils from Kerman, Iran

    Directory of Open Access Journals (Sweden)

    Mohammad Reazai

    2014-01-01

    Full Text Available Recently, there has been a great deal of attention on usage, byproducts, and wastes of the food industry. There have been many studies on the properties of citrus seeds and extracted oil from citrus grown in Kerman, Iran. The rate of oil content of citrus seeds varies between 33.4% and 41.9%. Linoleic acid (33.2% to 36.3% is the key fatty acid found in citrus seeds oil and oleic (24.8% to 29.3% and palmitic acids (23.5% to 29.4% are the next main fatty acids, respectively. There are also other acids found at trivial rates such as stearic, palmitoleic, and linolenic. With variation between 0.54 meg/kg and 0.77 mgq/kg in peroxide values of citrus seed oils, acidity value of the oil varies between 0.44% and 0.72%. The results of the study showed that citrus seeds under study (orange and sour lemon grown in Kerman province and the extracted oil have the potential of being used as the source of edible oil.

  6. In vitro organogenesis in some citrus species

    Directory of Open Access Journals (Sweden)

    Evandro Henrique Schinor

    2011-06-01

    Full Text Available In vitro organogenesis of Citrus was studied for the genotypes Citrus sinensis cv. 'Natal', C. limonia, C. volkameriana, and C. aurantium, with the use of epicotyl segments-derived explants, cultured in MT salts and vitamins medium supplemented with different concentrations of 6-benzylaminopurine (BAP - 0.0; 0.5; 1.0; 1.5 or 2.0 mg L-1. For the recalcitrant genotypes C. limonia and C. aurantium the in vitro organogenesis was also studied with internodal segments-derived explants, cultured in MT salts and vitamins medium supplemented with 0; 0.5; 1.0; 2.0, or 4.0 mg L-1 of BAP. The efficiency of culture medium supplementation with the combination of BAP (0.0; 1.0, or 2.0 mg L-1 and NAA (1-naphthaleneacetic acid - 0.0; 0.3, or 0.5 mg L-1 in the development of adventitious shoots was evaluated for C. aurantium. Culture medium supplementation with BAP is not essential for the adventitious shoots development in the four genotypes studied when epicotyl segments-derived explants are used. In general, culture media supplementation with BAP decreased the percentage of responsive explants excepted for C. sinensis cv. 'Natal' and C. limonia when the concentrations of 1.5 and 2.0 mg/L were used. The presence of cytokinin, in concentrations up to 2 mg/L, stimulated the in vitro organogenesis when internodal segments-derived explants were used for C. limonia and C. aurantium. For C. aurantium no adventitious shoots developed in explants (internodal segments cultured in basal culture medium, without BAP supplementation. Although no statistic differences could be detected, culture media supplementation with the combination of BAP and NAA favored the development of adventitious shoots in C. aurantium. The best concentration of NAA varied according to BAP concentration. The results presented herein, show that Citrus in vitro organogenesis depends on the interaction of culture medium composition, explant differentiation level, and genotype.

  7. Immunogenesity of spesific protein molecular weight 16 KDa (PS16 leaf of siam citrus infected by citrus vein phloem degeneration (CVPD disease

    Directory of Open Access Journals (Sweden)

    Made Sritamin

    2012-02-01

    Full Text Available Citrus Vein Phloem degeneration (CVPD is an important citrus disese, which damaged citrus plantation and causing decrease of citrus production. In Indonesia, the CVPD disease caused by Liberobacter asiaticum bactery and the disease spread out by vectir insect Diaphorina citri and using infected bud in wood grafting. In infected citrus plant, two specific protein molecules with molecular weigt 16 kDa and 66 kDa are found. These protein molecules are not found in healthy citrus plant. The immunogenicity of PS16 accumulated on leaf of citrus plant infected by CVPD is known yet. The research material were leaves of citrus plant infected CVPD, leaves of healthy citrus plant and reagent used these research are for isolation of the total protein leaf of citrus plant, SDS-PAGE electroforesis, electroelution of PS16, ELISA Methods, Dot-Blot Method, anti-PS16 as aprimery antibody and secondary antibody is anti-Rabbit IgG Conjugated AP. The result of the research showed that of PS16 accumulated on leaf of citrus plant infected CVPD has immunogenic character. It is indicated by increase of the titer anti-PS16 after first immunization ang 2nd booster by indirect ELISA method and can be used to induce antibody (anti-PS16 and so showed that positive reaction between PS16 with anti-PS16. It is indicated by purples dark blue on cellulose membrane by Dot Blot method.

  8. Identification and characterization of volatile components of the Japanese sour citrus fruit Citrus nagato-yuzukichi Tanaka.

    Science.gov (United States)

    Akakabe, Yoshihiko; Sakamoto, Mei; Ikeda, Yukinori; Tanaka, Mamoru

    2008-07-01

    A total of 39 aroma compounds were detected in the essential oil of Citrus nagato-yuzukichi Tanaka (nagato-yuzukichi) by gas chromatography-mass spectrometry (GC-MS). The essential oil was characterized by a high percentage of monoterpene hydrocarbons (12 components, 90.52%). The composition pattern of essential oil in C. nagato-yuzukichi was fairly similar to that of Citrus sudachi Hort. ex Shirai (Sudachi). Principal component analysis (PCA) of data obtained with an electronic nose indicated a variation of each oil along PC1. The oils of Citrus junos Tanaka (Yuzu) and Citrus sphaerocarpa Tanaka (Kabosu) showed a clear upward displacement as compared with those of C. nagato-yuzukichi and C. sudachi. However, in PC2, the oils of C. nagato-yuzukichi and C. sudachi showed a displacement in a negative direction and a positive one respectively.

  9. Phylogeography of the walnut twig beetle, Pityophthorus juglandis, the vector of thousand cankers disease in North American walnut trees.

    Directory of Open Access Journals (Sweden)

    Paul F Rugman-Jones

    Full Text Available Thousand cankers disease (TCD of walnut trees (Juglans spp. results from aggressive feeding in the phloem by the walnut twig beetle (WTB, Pityophthorus juglandis, accompanied by inoculation of its galleries with a pathogenic fungus, Geosmithia morbida. In 1960, WTB was only known from four U.S. counties (in Arizona, California, and New Mexico, but the species has now (2014 invaded over 115 counties, representing much of the western USA, and at least six states in the eastern USA. The eastern expansion places TCD in direct proximity to highly valuable (> $500 billion native timber stands of eastern black walnut, Juglans nigra. Using mitochondrial DNA sequences, from nearly 1100 individuals, we examined variation among 77 samples of WTB populations across its extended range in the USA, revealing high levels of polymorphism and evidence of two divergent lineages. The highest level of genetic diversity for the different lineages was found in the neighboring Madrean Sky Island and Western New Mexico regions, respectively. Despite their proximity, there was little evidence of mixing between these regions, with only a single migrant detected among 179 beetles tested. Indeed, geographic overlap of the two lineages was only common in parts of Colorado and Utah. Just two haplotypes, from the same lineage, predominated over the vast majority of the recently expanded range. Tests for Wolbachia proved negative suggesting it plays no role in "driving" the spread of particular haplotypes, or in maintaining deep levels of intraspecific divergence in WTB. Genotyping of ribosomal RNA corroborated the mitochondrial lineages, but also revealed evidence of hybridization between them. Hybridization was particularly prevalent in the sympatric areas, also apparent in all invaded areas, but absent from the most haplotype-rich area of each mitochondrial lineage. Hypotheses about the specific status of WTB, its recent expansion, and potential evolutionary origins of TCD

  10. Pseudomonas syringae pv. actinidiae from recent outbreaks of kiwifruit bacterial canker belong to different clones that originated in China.

    Directory of Open Access Journals (Sweden)

    Margi I Butler

    Full Text Available A recently emerged plant disease, bacterial canker of kiwifruit (Actinidia deliciosa and A. chinensis, is caused by Pseudomonas syringae pv. actinidiae (PSA. The disease was first reported in China and Japan in the 1980s. A severe outbreak of PSA began in Italy in 2008 and has spread to other European countries. PSA was found in both New Zealand and Chile in 2010. To study the evolution of the pathogen and analyse the transmission of PSA between countries, genomes of strains from China and Japan (where the genus Actinidia is endemic, Italy, New Zealand and Chile were sequenced. The genomes of PSA strains are very similar. However, all strains from New Zealand share several single nucleotide polymorphisms (SNPs that distinguish them from all other PSA strains. Similarly, all the PSA strains from the 2008 Italian outbreak form a distinct clonal group and those from Chile form a third group. In addition to the rare SNPs present in the core genomes, there is abundant genetic diversity in a genomic island that is part of the accessory genome. The island from several Chinese strains is almost identical to the island present in the New Zealand strains. The island from a different Chinese strain is identical to the island present in the strains from the recent Italian outbreak. The Chilean strains of PSA carry a third variant of this island. These genomic islands are integrative conjugative elements (ICEs. Sequencing of these ICEs provides evidence of three recent horizontal transmissions of ICE from other strains of Pseudomonas syringae to PSA. The analyses of the core genome SNPs and the ICEs, combined with disease history, all support the hypothesis of an independent Chinese origin for both the Italian and the New Zealand outbreaks and suggest the Chilean strains also originate from China.

  11. Pseudomonas syringae pv. actinidiae (PSA isolates from recent bacterial canker of kiwifruit outbreaks belong to the same genetic lineage.

    Directory of Open Access Journals (Sweden)

    Angelo Mazzaglia

    Full Text Available Intercontinental spread of emerging plant diseases is one of the most serious threats to world agriculture. One emerging disease is bacterial canker of kiwi fruit (Actinidia deliciosa and A. chinensis caused by Pseudomonas syringae pv. actinidiae (PSA. The disease first occurred in China and Japan in the 1980s and in Korea and Italy in the 1990s. A more severe form of the disease broke out in Italy in 2008 and in additional countries in 2010 and 2011 threatening the viability of the global kiwi fruit industry. To start investigating the source and routes of international transmission of PSA, genomes of strains from China (the country of origin of the genus Actinidia, Japan, Korea, Italy and Portugal have been sequenced. Strains from China, Italy, and Portugal have been found to belong to the same clonal lineage with only 6 single nucleotide polymorphisms (SNPs in 3,453,192 bp and one genomic island distinguishing the Chinese strains from the European strains. Not more than two SNPs distinguish each of the Italian and Portuguese strains from each other. The Japanese and Korean strains belong to a separate genetic lineage as previously reported. Analysis of additional European isolates and of New Zealand isolates exploiting genome-derived markers showed that these strains belong to the same lineage as the Italian and Chinese strains. Interestingly, the analyzed New Zealand strains are identical to European strains at the tested SNP loci but test positive for the genomic island present in the sequenced Chinese strains and negative for the genomic island present in the European strains. Results are interpreted in regard to the possible direction of movement of the pathogen between countries and suggest a possible Chinese origin of the European and New Zealand outbreaks.

  12. Antimicrobial Nanoemulsion Formulation with Improved Penetration of Foliar Spray through Citrus Leaf Cuticles to Control Citrus Huanglongbing.

    Science.gov (United States)

    Yang, Chuanyu; Powell, Charles A; Duan, Yongping; Shatters, Robert; Zhang, Muqing

    2015-01-01

    Huanglongbing (HLB) is the most serious disease affecting the citrus industry worldwide to date. The causal agent, Candidatus Liberibacter asiaticus (Las), resides in citrus phloem, which makes it difficult to effectively treat with chemical compounds. In this study, a transcuticular nanoemulsion formulation was developed to enhance the permeation of an effective antimicrobial compound (ampicillin; Amp) against HLB disease through the citrus cuticle into the phloem via a foliar spray. The results demonstrated that efficiency of cuticle isolation using an enzymatic method (pectinase and cellulase) was dependent on the citrus cultivar and Las-infection, and it was more difficult to isolate cuticles from valencia orange (Citrus sinensis) and HLB-symptomatic leaves. Of eight adjuvants tested, Brij 35 provided the greatest increase in permeability of the HLB-affected cuticle with a 3.33-fold enhancement of cuticular permeability over water control. An in vitro assay using Bacillus subtilis showed that nanoemulsion formulations containing Amp (droplets size = 5.26 ± 0.04 nm and 94 ± 1.48 nm) coupled with Brij 35 resulted in greater inhibitory zone diameters (5.75 mm and 6.66 mm) compared to those of Brij 35 (4.34 mm) and Amp solution (2.83 mm) alone. Furthermore, the nanoemulsion formulations eliminated Las bacteria in HLB-affected citrus in planta more efficiently than controls. Our study shows that a water in oil (W/O) nanoemulsion formulation may provide a useful model for the effective delivery of chemical compounds into citrus phloem via a foliar spray for controlling citrus HLB.

  13. Technical and Institutional Strategies for the Development of Algarve Citrus System - The Case of IGP "Algarve Citrus"

    OpenAIRE

    Madeira, Emilia; Guerreiro, João; Carvalho, Agostinho

    2010-01-01

    This research approaches some factors that have been affecting the competitiveness faced by the Algarve citrus culture since the European Single Market came into force and before a more and more global economy. As it is known in a global economy, any competitive strategy should be based on the quality seen as the ability to respond to the market, considering all the main types of actors at different levels of the Algarvian citrus system. Thus, the main objective was to identify any malfunctio...

  14. Estimation of Fluoride Concentration of Various Citrus and Non-Citrus Fruits Commonly Consumed and Commercially Available in Mathura City

    OpenAIRE

    Navin Anand Ingle; Alankrita Chaudhary; B S Goutham; Navpreet Kaur; Rahul Gupta

    2013-01-01

    Background: Since fluoride is available from various sources, the total ingestion of fluoride by a person should be estimated taking into consideration the fluoride consumed from all the sources including fruits. There are very few epidemiological studies carried out associated with fluoride estimation in fruit samplesand especially in the Indian scenario Objective: To estimate and compare the fluoride concentration of different commercially available citrus and non-citrus fruits in Math...

  15. Evaluation of triticale accessions for resistance to wheat bacterial leaf streak caused by Xanthomonas translucens pv. undulosa

    Science.gov (United States)

    The bacterium Xanthomonas translucens pv. undulosa (Xtu) causes bacterial leaf streak (BLS) on wheat and other small grains. Several triticale accessions were reported to possess high levels of resistance to wheat Xtu strains. In this study, we evaluated a worldwide collection of 502 triticale acces...

  16. Cloning of a two-component signal transduction system of Xanthomonas campestris pv. phaseoli var. fuscans strain BXPF65

    DEFF Research Database (Denmark)

    Chan, JWYF; Maynard, Scott; Goodwin, PH

    1998-01-01

    A putative two-component signal transduction system was amplified and cloned from the plant pathogenic bacterium Xanthomonas campestris pv. phaseoli var. fuscans isolate BXPF65. The 620 bp amplified fragment was sequenced and analyzed with the BLAST Enhanced Alignment Utility (BEAUTY). BEAUTY ana...

  17. FaRXf1: a locus conferring resistance to angular leaf spot caused by Xanthomonas fragariae in octoploid strawberry

    Science.gov (United States)

    Angular leaf spot caused by Xanthomonas fragariae is the only major bacterial disease of cultivated strawberry (Fragaria ×ananassa). While this disease may cause reductions of up to 8 % of marketable yield in Florida winter annual production, no resistant cultivars have been commercialized. Wild acc...

  18. A loop-mediated isothermal amplification assay and sample preparation procedure for sensitive detection of Xanthomonas fragariae in strawberry

    Science.gov (United States)

    Xanthomonas fragariae is a bacterium that causes angular leaf spot of strawberry. Asymptomatic infections are common and contribute to the difficulties in disease management. The aim of this study was to develop a loop-mediated isothermal amplification (LAMP) assay with a bacterial enrichment proced...

  19. Colonization of cauliflower blossom (Brassica oleracea) by Xanthomonas campestris pv. campestris, via flies (Calliphora vomitoria) can result in seed infestation

    NARCIS (Netherlands)

    Wolf, van der J.M.; Zouwen, van der P.S.

    2010-01-01

    Inoculation of cauliflower blossom with Xanthomonas campestris pv. campestris (Xcc), by brush or pollination with blue bottle flies (Calliphora vomitoria) as a vector, can result in seed infestation. Two years of poly-tunnel experiments with fly inoculation of cauliflower has shown that in approxima

  20. Minimal Phenotypic Test for Simple Differentiation of Xanthomonas Campestris from other Yellow-Pigmented Bacteria Isolated from Soil

    Directory of Open Access Journals (Sweden)

    MR Soudi

    2011-06-01

    Full Text Available Background and Objectives: Isolation of Xanthomonas campestris from soil has a wide range of applications from monitoring of phytopathogenic populations in soil to screening of improved xanthan-producing strains. Identification of Xanthomonas campestris and its pathovars requires pathogenicity tests in addition to phenotypic and molecular characterization.Materials and Methods: Thirty phenotypic tests were carried out on 57 yellow-pigmented bacterial isolates obtained from soil of cabbage farms after screening on Selective Xanthomonas (SX agar and transferring on Yeast Malt agar. Absorption spectra of pigments and capability of biopolymer production were determined for the isolates. Some characteristics of the biopolymer produced and presence of a X. campestris-specific gene marker were investigated for nine putative X. campestris isolates.Results: The present study introduces a set of simple phenotypic tests including urease, acid production from sucrose, mucoid growth on 5% sucrose, starch hydrolysis, growth in 4% NaCl, motility and utilization of asparagine as sole carbon and nitrogen source for quick and inexpensive tentative identification of Xanthomonas campestris. Validation of these tests was confirmed in 100% of the cases by characterization of bacterial exopolysaccharide as xanthan and production of genus-specific xanthomonadin pigment. Moreover, tracking of hrc gene among putative X. campestris isolates gave positive results in 80% of cases.Conclusion: The Minimal simple phenotypic tests facilitate the screening and differentiation of putative X. campestris isolates from other false bacterial strains isolated from soil on semiselective SX agar.

  1. Anticancer Activity of Key Lime, Citrus aurantifolia.

    Science.gov (United States)

    Narang, Nithithep; Jiraungkoorskul, Wannee

    2016-01-01

    Citrus aurantifolia (family: Rutaceae) is mainly used in daily consumption, in many cultural cuisines, and in juice production. It is widely used because of its antibacterial, anticancer, antidiabetic, antifungal, anti-hypertensive, anti-inflammation, anti-lipidemia, and antioxidant properties; moreover, it can protect heart, liver, bone, and prevent urinary diseases. Its secondary metabolites are alkaloids, carotenoids, coumarins, essential oils, flavonoids, phenolic acids, and triterpenoids. The other important constituents are apigenin, hesperetin, kaempferol, limonoids, quercetin, naringenin, nobiletin, and rutin, all of these contribute to its remedial properties. The scientific searching platforms were used for publications from 1990 to present. The abstracts and titles were screened, and the full-text articles were selected. The present review is up-to-date of the phytochemical property of C. aurantifolia to provide a reference for further study.

  2. Pharmacognostical evaluation of Citrus jambhiri Lush. fruit

    Directory of Open Access Journals (Sweden)

    Swapnil Y Chaudhari

    2014-01-01

    Full Text Available Background: Citrus jambhiri Lush., commonly known as Jambīra Nimbū in Sanskrit is medium to large indigenous tree with spreading habit, less spiny than lemon and belonging to the family Rutaceae. In Ayurveda, it is used in many pharmaceutical procedures of purification (Śodhana, calcination (Māraṇa etc., Though it is an important plant, till date, no pharmacognostical reports have been available on its fruit. Materials and Methods: Study of fruit and its powder, histochemical tests and preliminary physicochemical investigations were done. Results and Conclusion: Results showed prismatic crystals of calcium oxalate, aerenchyma cells, oil globules, pitted vessels, scalariform vessels, juicy sac, etc., Preliminary physicochemical analysis revealed loss on drying (1.1%, ash value (1.4%, alcohol soluble extract (28.6%, and water soluble extract (53.3%. These observations can be of use in future studies.

  3. Worker exposure to ethion in Florida citrus.

    Science.gov (United States)

    Wojeck, G A; Nigg, H N; Stamper, J H; Bradway, D E

    1981-11-01

    Dermal and respiratory exposure to ethion was determined for 17 men in eight spray crews in Florida citrus spray operations. Respiratory exposure was less than 1% of the total exposure. Hands represented 42% of the total body exposure for applicators and 76% for suppliers. At one location, suppliers exhibited a larger decrease in ChE activity than applicators. This difference appeared related to the higher mean dermal ethion exposure to suppliers. Acute symptoms of organophosphorous poisoning were not observed. The total percent/hr of the probable human dermal LD50 was very low in all cases. These data indicate a relatively low potential acute hazard to workers applying ethion with air blast equipment under the conditions of this study.

  4. Antimicrobial Activity and Phytochemical Analysis of Citrus Fruit Peels -Utilization of Fruit Waste

    Directory of Open Access Journals (Sweden)

    K. Ashok kumar

    2011-06-01

    Full Text Available Antibacterial activity of five different solvent extracts(ethyl acetate, acetone, ethanol, petroleum ether and water prepared by soxhlet extractor from two citrus fruit peel (Citrus sinensis and Citrus limon were screened against five pathogenic bacteria Staphylococcus aureus, Bacillus subtilis, Escherichia coli , Klebsiella pneumonia and Salmonella typhi. The highest antibacterial potentiality was exhibited by the acetone peel extract of Citrus sinensis followed by the ethyl acetate peel extract of Citrus limon. The peel extract of Citrus sinensis and Citrus limon can be considered to be as equally potent as the antibiotics, such as metacillin and penicillin. MICs were tested at concentrations ranging from 50-6.25 mg/ml as wells as their MBCs. The phytochemical analysis of the citrus peel extracts showed the presence of flavonoids, saponins, steroids, terpenoids, tannins and alkaloids

  5. Sequencing of diverse mandarin, pummelo and orange genomes reveals complex history of admixture during citrus domestication.

    Science.gov (United States)

    Wu, G Albert; Prochnik, Simon; Jenkins, Jerry; Salse, Jerome; Hellsten, Uffe; Murat, Florent; Perrier, Xavier; Ruiz, Manuel; Scalabrin, Simone; Terol, Javier; Takita, Marco Aurélio; Labadie, Karine; Poulain, Julie; Couloux, Arnaud; Jabbari, Kamel; Cattonaro, Federica; Del Fabbro, Cristian; Pinosio, Sara; Zuccolo, Andrea; Chapman, Jarrod; Grimwood, Jane; Tadeo, Francisco R; Estornell, Leandro H; Muñoz-Sanz, Juan V; Ibanez, Victoria; Herrero-Ortega, Amparo; Aleza, Pablo; Pérez-Pérez, Julián; Ramón, Daniel; Brunel, Dominique; Luro, François; Chen, Chunxian; Farmerie, William G; Desany, Brian; Kodira, Chinnappa; Mohiuddin, Mohammed; Harkins, Tim; Fredrikson, Karin; Burns, Paul; Lomsadze, Alexandre; Borodovsky, Mark; Reforgiato, Giuseppe; Freitas-Astúa, Juliana; Quetier, Francis; Navarro, Luis; Roose, Mikeal; Wincker, Patrick; Schmutz, Jeremy; Morgante, Michele; Machado, Marcos Antonio; Talon, Manuel; Jaillon, Olivier; Ollitrault, Patrick; Gmitter, Frederick; Rokhsar, Daniel

    2014-07-01

    Cultivated citrus are selections from, or hybrids of, wild progenitor species whose identities and contributions to citrus domestication remain controversial. Here we sequence and compare citrus genomes--a high-quality reference haploid clementine genome and mandarin, pummelo, sweet-orange and sour-orange genomes--and show that cultivated types derive from two progenitor species. Although cultivated pummelos represent selections from one progenitor species, Citrus maxima, cultivated mandarins are introgressions of C. maxima into the ancestral mandarin species Citrus reticulata. The most widely cultivated citrus, sweet orange, is the offspring of previously admixed individuals, but sour orange is an F1 hybrid of pure C. maxima and C. reticulata parents, thus implying that wild mandarins were part of the early breeding germplasm. A Chinese wild 'mandarin' diverges substantially from C. reticulata, thus suggesting the possibility of other unrecognized wild citrus species. Understanding citrus phylogeny through genome analysis clarifies taxonomic relationships and facilitates sequence-directed genetic improvement.

  6. Isolation, characterization and modification of citrus pectins

    Directory of Open Access Journals (Sweden)

    MARIA KRATCHANOVA

    2012-01-01

    Full Text Available Orange and lemon peels were used for obtaining pectic polysaccharides. Citrus peels were previously treated with 96% ethanol, and the obtained alcohol-insoluble solids (AIS were subjected to a sequential extraction with hot distilled water and hot 0.5% HCl. Water- and acid-extracted orange (WEOP and AEOP and lemon (WELP and AELP pectins were obtained. Acid extraction gave higher yields of pectin than water extraction and lemon peels were richer in pectin. Comparative investigations were carried out with chromatographically purified commercial citrus pectin (CPCP. Chemical and physicochemical characterization of all pectins was accomplished. It was found that pectins were similar in anhydrouronic acid content (AUАC, 69-81%, but differed in their degree of methylesterification (DM, 55-81%. Generally water-extracted pectins were with higher DM. Both orange pectins were with higher DM and degree of acetylation (DA, 2%, in comparison with the corresponding lemon pectins. Water-extracted pectins were with higher degree of feruloylation (DF, 0.12-0.34%. To our knowledge this is the first report on the estimation of ester-linked ferulic acid in orange and lemon peel pectins. Pectic polysaccharides differed in molecular weight and homogeneity. WELP was with the highest molecular weight and homogeneity. The pectins contained D-galacturonic and D-glucuronic acids, L-arabinose, D-galactose, L-fucose, L-rhamnose and D-xylose. All investigated pectins showed immunostimulating activity by complement activation in the classical pathway at 1.25 and 2.5 mg/mL. Pectic polysaccharides were modified with endopolygalacturonase. Enzyme-modified CPCP and WEOP had higher anti-complementary activity than the corresponding initial pectins.

  7. Transcriptome profiling of Xanthomonas campestris pv. campestris grown in minimal medium MMX and rich medium NYG.

    Science.gov (United States)

    Liu, Wei; Yu, Yan-Hua; Cao, Shi-Yuan; Niu, Xiang-Na; Jiang, Wei; Liu, Guo-Fang; Jiang, Bo-Le; Tang, Dong-Jie; Lu, Guang-Tao; He, Yong-Qiang; Tang, Ji-Liang

    2013-06-01

    Xanthomonas campestris pathovar campestris (Xcc) is the causal agent of black rot disease in cruciferous plants worldwide. Although the complete genomes of several Xcc strains have been determined, the gene expression and regulation mechanisms in this pathogen are far from clear. In this work, transcriptome profiling of Xcc 8004 grown in MMX medium (minimal medium for Xanthomonas campestris) and NYG medium (peptone yeast glycerol medium) were investigated by RNA-Seq. Using the Illumina HiSeq 2000 platform, a total of 26,514,630 reads (90 nt in average) were generated, of which 15,708,478 reads mapped uniquely to coding regions of Xcc 8004 genome. Of the 4273 annotated protein-coding genes of Xcc 8004, 629 were found differentially expressed in Xcc grown in MMX and NYG. Of the differentially expressed genes, 495 were up-regulated and 134 were down-regulated in MMX. The MMX-induced genes are mainly involved in amino acid metabolism, transport systems, atypical condition adaptation and pathogenicity, especially the type III secretion system, while the MMX-repressed genes are mainly involved in chemotaxis and degradation of small molecules. The global transcriptome analyzes of Xcc 8004 grown in MMX and NYG might facilitate the gene functional characterization of this phytopathogenic bacterium.

  8. Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10

    Directory of Open Access Journals (Sweden)

    Teresa Weise

    2012-04-01

    Full Text Available Xanthomonas campestris is a phytopathogenic bacterium and causes many diseases of agricultural relevance. Volatiles were shown to be important in inter- and intraorganismic attraction and defense reactions. Recently it became apparent that also bacteria emit a plethora of volatiles, which influence other organisms such as invertebrates, plants and fungi. As a first step to study volatile-based bacterial–plant interactions, the emission profile of Xanthomonas c. pv. vesicatoria 85-10 was determined by using GC/MS and PTR–MS techniques. More than 50 compounds were emitted by this species, the majority comprising ketones and methylketones. The structure of the dominant compound, 10-methylundecan-2-one, was assigned on the basis of its analytical data, obtained by GC/MS and verified by comparison of these data with those of a synthetic reference sample. Application of commercially available decan-2-one, undecan-2-one, dodecan-2-one, and the newly synthesized 10-methylundecan-2-one in bi-partite Petri dish bioassays revealed growth promotions in low quantities (0.01 to 10 μmol, whereas decan-2-one at 100 μmol caused growth inhibitions of the fungus Rhizoctonia solani. Volatile emission profiles of the bacteria were different for growth on media (nutrient broth with or without glucose.

  9. Volatile organic compounds produced by the phytopathogenic bacterium Xanthomonas campestris pv. vesicatoria 85-10.

    Science.gov (United States)

    Weise, Teresa; Kai, Marco; Gummesson, Anja; Troeger, Armin; von Reuß, Stephan; Piepenborn, Silvia; Kosterka, Francine; Sklorz, Martin; Zimmermann, Ralf; Francke, Wittko; Piechulla, Birgit

    2012-01-01

    Xanthomonas campestris is a phytopathogenic bacterium and causes many diseases of agricultural relevance. Volatiles were shown to be important in inter- and intraorganismic attraction and defense reactions. Recently it became apparent that also bacteria emit a plethora of volatiles, which influence other organisms such as invertebrates, plants and fungi. As a first step to study volatile-based bacterial-plant interactions, the emission profile of Xanthomonas c. pv. vesicatoria 85-10 was determined by using GC/MS and PTR-MS techniques. More than 50 compounds were emitted by this species, the majority comprising ketones and methylketones. The structure of the dominant compound, 10-methylundecan-2-one, was assigned on the basis of its analytical data, obtained by GC/MS and verified by comparison of these data with those of a synthetic reference sample. Application of commercially available decan-2-one, undecan-2-one, dodecan-2-one, and the newly synthesized 10-methylundecan-2-one in bi-partite Petri dish bioassays revealed growth promotions in low quantities (0.01 to 10 μmol), whereas decan-2-one at 100 μmol caused growth inhibitions of the fungus Rhizoctonia solani. Volatile emission profiles of the bacteria were different for growth on media (nutrient broth) with or without glucose.

  10. Transgenic banana expressing Pflp gene confers enhanced resistance to Xanthomonas wilt disease.

    Science.gov (United States)

    Namukwaya, B; Tripathi, L; Tripathi, J N; Arinaitwe, G; Mukasa, S B; Tushemereirwe, W K

    2012-08-01

    Banana Xanthomonas wilt (BXW), caused by Xanthomonas campestris pv. musacearum, is one of the most important diseases of banana (Musa sp.) and currently considered as the biggest threat to banana production in Great Lakes region of East and Central Africa. The pathogen is highly contagious and its spread has endangered the livelihood of millions of farmers who rely on banana for food and income. The development of disease resistant banana cultivars remains a high priority since farmers are reluctant to employ labor-intensive disease control measures and there is no host plant resistance among banana cultivars. In this study, we demonstrate that BXW can be efficiently controlled using transgenic technology. Transgenic bananas expressing the plant ferredoxin-like protein (Pflp) gene under the regulation of the constitutive CaMV35S promoter were generated using embryogenic cell suspensions of banana. These transgenic lines were characterized by molecular analysis. After challenge with X. campestris pv. musacearum transgenic lines showed high resistance. About 67% of transgenic lines evaluated were completely resistant to BXW. These transgenic lines did not show any disease symptoms after artificial inoculation of in vitro plants under laboratory conditions as well as potted plants in the screen-house, whereas non-transgenic control plants showed severe symptoms resulting in complete wilting. This study confirms that expression of the Pflp gene in banana results in enhanced resistance to BXW. This transgenic technology can provide a timely solution to the BXW pandemic.

  11. 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.

  12. Establishment of an inducing medium for type III effector secretion in Xanthomonas campestris pv. campestris

    Directory of Open Access Journals (Sweden)

    Guo-Feng Jiang

    2013-09-01

    Full Text Available It is well known that the type III secretion system (T3SS and type III (T3 effectors are essential for the pathogenicity of most bacterial phytopathogens and that the expression of T3SS and T3 effectors is suppressed in rich media but induced in minimal media and plants. To facilitate in-depth studies on T3SS and T3 effectors, it is crucial to establish a medium for T3 effector expression and secretion. Xanthomonas campestris pv. campestris (Xcc is a model bacterium for studying plant-pathogen interactions. To date no medium for Xcc T3 effector secretion has been defined. Here, we compared four minimal media (MME, MMX, XVM2, and XOM2 which are reported for T3 expression induction in Xanthomonas spp. and found that MME is most efficient for expression and secretion of Xcc T3 effectors. By optimization of carbon and nitrogen sources and pH value based on MME, we established XCM1 medium, which is about 3 times stronger than MME for Xcc T3 effectors secretion. We further optimized the concentration of phosphate, calcium, and magnesium in XCM1 and found that XCM1 with a lower concentration of magnesium (renamed as XCM2 is about 10 times as efficient as XCM1 (meanwhile, about 30 times stronger than MME. Thus, we established an inducing medium XCM2 which is preferred for T3 effector secretion in Xcc.

  13. STUDIES ON ANTIMICROBIAL ACTIVITY AND PHYTOCHEMICAL ANALYSIS OF CITRUS FRUIT JUICES AGAINST SELECTED ENTERIC PATHOGENS

    OpenAIRE

    Bansode.D.S.; Chavan.M.D.

    2012-01-01

    The present study was carried out to find out the antimicrobial activity and phytochemical study of citrus fruit juices viz. Lemon (Citrus limon) and Orange (Citrus ourantium) against medically important selected enteric pathogens. As microorganisms are becoming resistant to present day antibiotics, our study focuses on antimicrobial activity and phytochemical study of Citrus fruit juices against selected enteric pathogens. Biological active compounds present in the medicinal important fruit ...

  14. Elucidating genetic variation in Candidatus Liberibacter asiaticus transmission between Asian citrus psyllid isofemale lines

    OpenAIRE

    Dixon, Danielle; Kruse, Annie; Ramsey, John; Hosmani, Prashant; Hall, David; Saha, Surya; Ammar, El-Desouky; Cilia, Michelle; Mueller, Lukas A

    2017-01-01

    Citrus greening disease or Huanglongbing (HLB) is an epidemic bacterial infection that has devastated citrus industries across the globe. HLB leads to a reduction in fruit quality, decrease in overall fruit production and eventual death of the citrus tree.The disease is associated with this bacterium Candidatus Liberibacter asiaticus (CLas), is transmitted by the Asian citrus psyllid (ACP).Objective 1: Improve the current psyllid genome through manual curation.Objective 2: Characterize genet...

  15. First report of the citrus Hindu mite, Schizotetranychus hindustanicus (Hirst) (Prostigmata: Tetranychidae), in Brazil.

    Science.gov (United States)

    Navia, Denise; Marsaro, Alberto L

    2010-01-01

    The citrus Hindu mite, Schizotetranychus hindustanicus (Hirst), is reported for the first time in Brazil and for the second time in South America. Mite specimens were collected from citrus in the municipality of Boa Vista, State of Roraima, northern Brazil. Symptoms associated with S.hindustanicus infestations on citrus are described. The importance of avoiding dissemination of this mite to the main citrus production areas in Brazil is discussed.

  16. Antimicrobial Activity and Phytochemical Analysis of Citrus Fruit Peels -Utilization of Fruit Waste

    OpenAIRE

    K. Ashok Kumar; Narayani, M.; A. Subanthini; Jayakumar, M.

    2011-01-01

    Antibacterial activity of five different solvent extracts(ethyl acetate, acetone, ethanol, petroleum ether and water) prepared by soxhlet extractor from two citrus fruit peel (Citrus sinensis and Citrus limon) were screened against five pathogenic bacteria Staphylococcus aureus, Bacillus subtilis, Escherichia coli , Klebsiella pneumonia and Salmonella typhi. The highest antibacterial potentiality was exhibited by the acetone peel extract of Citrus sinensis followed by the ethyl acetate peel e...

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

    OpenAIRE

    Araujo, W.L.; Marcon, J; Maccheroni, jr., W.; Elsas, van, J.D.; Vuurde, van, M.; Azevedo

    2002-01-01

    Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as cultivation-independent techniques. The endophytic communities were assessed in surface-disinfected citrus branches by plating and denaturing gradient gel electrophoresis (DGGE). Dominant isolates were characterized by ...

  18. The noncanonical type III secretion system of Xanthomonas translucens pv. graminis is essential for forage grass infection.

    Science.gov (United States)

    Wichmann, Fabienne; Vorhölter, Frank-Jörg; Hersemann, Lena; Widmer, Franco; Blom, Jochen; Niehaus, Karsten; Reinhard, Sonja; Conradin, Constanze; Kölliker, Roland

    2013-08-01

    Xanthomonas translucens pv. graminis (Xtg) is a gammaproteobacterium that causes bacterial wilt on a wide range of forage grasses. To gain insight into the host-pathogen interaction and to identify the virulence factors of Xtg, we compared a draft genome sequence of one isolate (Xtg29) with other Xanthomonas spp. with sequenced genomes. The type III secretion system (T3SS) encoding a protein transport system for type III effector (T3E) proteins represents one of the most important virulence factors of Xanthomonas spp. In contrast with other Xanthomonas spp. assigned to clade 1 on the basis of phylogenetic analyses, we identified an hrp (hypersensitive response and pathogenicity) gene cluster encoding T3SS components and a representative set of 35 genes encoding putative T3Es in the genome of Xtg29. The T3SS was shown to be divergent from the hrp gene clusters of other sequenced Xanthomonas spp. Xtg mutants deficient in T3SS regulating and structural genes were constructed to clarify the role of the T3SS in forage grass colonization. Italian ryegrass infection with these mutants led to significantly reduced symptoms (P < 0.05) relative to plants infected with the wild-type strain. This showed that the T3SS is required for symptom evocation. In planta multiplication of the T3SS mutants was not impaired significantly relative to the wild-type, indicating that the T3SS is not required for survival until 14 days post-infection. This study represents the first major step to understanding the bacterial colonization strategies deployed by Xtg and may assist in the identification of resistance (R) genes in forage grasses.

  19. Factors affecting transmission rates of 'Candidatus Liberibacter asiaticus' by Asian citrus psyllid

    Science.gov (United States)

    The Asian citrus psyllid (ACP), Diaphorina citri, is an important pest because it transmits a bacterium ‘Candidatus Liberibacter asiaticus’ (CLas) responsible for a serious disease of citrus known as Asiatic huanglongbing (citrus greening disease). USDA-ARS researchers recently established a program...

  20. Protocol for introducing new and licensed citrus varieties into California. A Florida case study.

    Science.gov (United States)

    In the light of the current Huanglongbing (HLB) threat to the California (CA) citrus industry, and preliminary data indicating that some citrus varieties in Florida (FL) may possess some degree of tolerance to HLB, the California citrus growers indicated a strong interest in proactively introducing ...

  1. Detection of Citrus Huanglongbing by Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR) Spectroscopy

    Science.gov (United States)

    Citrus Huanglongbing (HLB, also known as citrus greening disease) was discovered in Florida in 2005 and is spreading rapidly amongst the citrus growing regions of the state. Detection via visual symptoms of the disease is not a long term viable option. New techniques are being developed to test fo...

  2. First record of Anastrepha serpentina (Wiedemann) (Diptera: Tephritidae) in citrus in Brazil.

    Science.gov (United States)

    Lemos, W P; da Silva, R A; Araújo, S C A; Oliveira, E L A; da Silva, W R

    2011-01-01

    Anastrepha serpentina (Wiedemann) is recorded for the first time in citrus (Rutaceae) in Brazil. Specimens were obtained from sweet orange (Citrus sinensis) sampled in the municipalities of Belém and Capitão Poço, and from mandarin orange (Citrus reticulata) from Tomé-Açu, state of Pará, Brazil.

  3. Incidence of ‘Candidatus Liberibacter asiaticus’ in a Florida population of Asian citrus psyllid

    Science.gov (United States)

    A study was conducted to assess the incidence of a bacterium ‘Candidatus Liberibacter asiaticus’ in a Florida population of Asian citrus psyllid (ACP), Diaphorina citri. The bacterium is the presumed causal agent of Asiatic huanglongbing, a serious citrus disease also known as citrus greening or yel...

  4. 78 FR 22411 - Common Crop Insurance Regulations; Florida Citrus Fruit Crop Insurance Provisions; Correction

    Science.gov (United States)

    2013-04-16

    ... Corporation 7 CFR Part 457 RIN 0563-AC39 Common Crop Insurance Regulations; Florida Citrus Fruit Crop... Florida Citrus Fruit Crop Insurance Provisions that published on Friday, December 21, 2012, (74 FR 75509... Subjects in 7 CFR Part 457 Crop insurance, Florida citrus fruit, Reporting and recordkeeping requirements...

  5. Sequencing of diverse mandarin, pummelo and orange genomes reveals complex history of admixture during citrus domestication

    Science.gov (United States)

    Cultivated citrus are selections from, or hybrids of, wild progenitor species whose identities and contributions to citrus domestication remain controversial. Here we sequence and compare citrus genomes—a high-quality reference haploid clementine genome and mandarin, pummelo, sweet-orange and sour-o...

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

    NARCIS (Netherlands)

    Araujo, W.L.; Marcon, J.; Maccheroni, jr. W.; Elsas, van J.D.; Vuurde, van J.W.L.; Azevedo, de J.L.

    2002-01-01

    Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as cultivation-independen

  7. 7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.

    Science.gov (United States)

    2010-01-01

    ... Fruit § 905.149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run citrus fruit. Tree run citrus fruit as referenced in this section is defined in the Florida Department of... grower shall apply to ship tree run fruit using a Grower Tree Run Certificate Application, furnished...

  8. First Report of Dodder Transmission of Huanglongbing from Naturally Infected Murraya paniculata to Citrus

    Science.gov (United States)

    Huanglongbing (HLB) or “greening” disease of citrus is caused by phloem-limited, uncultured bacteria in the genus “Candidatus Liberibacter”. HLB is one of the most destructive diseases of citrus worldwide and is considered so dangerous to a U.S. citrus production that the USDA has listed “Ca. Liberi...

  9. Genes diferencialmente expressos em cana-de-açúcar inoculada com Xanthomonas albilineans, o agente causal da escaldadura da folha

    National Research Council Canada - National Science Library

    Karina Maia Dabbas; Maria Inês Tiraboschi Ferro; Neli Martins de Barros; Marcelo Luiz de Laia; Sonia Marli Zingaretti; Poliana Fernanda Giachetto; Vicente Alberto de Moraes; Jesus Aparecido Ferro

    2006-01-01

    ...) em folhas de cana-de-açúcar. Foram utilizadas duas variedades, uma resistente (SP82-1176) e outra suscetível (SP78-4467) a Xanthomonas albilineans as quais foram infectadas mecanicamente por ferimentos...

  10. Development of immunofluorescence colony staining (IFC) for detection of Xanthomonas campestris pv. vesicatoria and Clavibacter michiganensis subsp michiganensis in tomato seeds

    NARCIS (Netherlands)

    Nemeth, J.; Vuurde, van J.W.L.

    2006-01-01

    Immunofluorescence colony-staining (IFC) is based on sample pour plating in combination with immunofluorescence staining for recognition of the target colony. IFC was optimised for detecting Xanthomonas campestris pv. vesicatoria (Xcv) and Clavibacter michiganensis subsp. michiganensis (Cmm) in

  11. Multiplex PCR for specific and robust detection of Xanthomonas campestris pv. musacearum in pure culture and infected plant material

    DEFF Research Database (Denmark)

    Adriko, John; Aritua, V.; Mortensen, Carmen Nieves

    2012-01-01

    The present study developed a pathovar-specific PCR for the detection of Xanthomonas campestris pv. musacearum (Xcm), the cause of banana xanthomonas wilt, by amplification of a 265-bp region of the gene encoding the general secretion pathway protein D (GspD). A distinct DNA fragment of the expec......The present study developed a pathovar-specific PCR for the detection of Xanthomonas campestris pv. musacearum (Xcm), the cause of banana xanthomonas wilt, by amplification of a 265-bp region of the gene encoding the general secretion pathway protein D (GspD). A distinct DNA fragment...... was subsequently demonstrated in tests on artificially inoculated screenhouse cultivars of banana and field bananas with and without symptoms sampled from different parts of Uganda. This study therefore demonstrated a robust and specific Xcm diagnostic tool with the added advantage of applying internal PCR...

  12. Transporte de Xanthomonas vesicatoria de sementes para plântulas e mudas de tomate Transport of Xanthomonas vesicatoria from seeds to seedlings and to plants of tomato

    Directory of Open Access Journals (Sweden)

    Débora AG da Silva

    2013-03-01

    Full Text Available O transporte e a transmissão de bactérias do complexo Xanthomonas vesicatoria pelas sementes de tomate é um dos principais mecanismos de sobrevivência e disseminação do patógeno para novas áreas. O presente trabalho foi desenvolvido com o objetivo de elucidar o processo de infecção e colonização das sementes, plântulas e mudas de tomate. Foram realizados experimentos utilizando o isolado ENA 4463 de X. vesicatoria e a cultivar Santa Clara Miss Brasil, cujas sementes foram inoculadas a vácuo ou por injeção de suspensão bacteriana na região da placenta de frutos verdes. O semeio foi feito em caixas Gerbox, contendo papel germitest, bandejas de alumínio contendo areia ou bandejas de isopor (128 células, contendo substrato comercial para produção de mudas. As avaliações nos testes em Gerbox foram feitas ao longo de seis dias por isolamentos diretos e indiretos em meio NA para quantificação da população bacteriana associada aos diferentes órgãos das plântulas. Nos testes de emergência em areia e em substrato, foram realizadas avaliações ao longo de 30 dias utilizando os mesmos procedimentos. A fitobactéria foi facilmente reisolada do tegumento ao longo dos primeiros seis dias e da radícula, do hipocótilo e folhas cotiledonares logo após a sua emissão aos dois e três dias do semeio, respectivamente. A máxima população de X. vesicatoria foi observada às 48 h após o semeio por ocasião da emissão da radícula. Nos experimentos em areia e em substrato comercial, observou-se que a bactéria, a partir do tegumento, coloniza todos os órgãos da planta à medida que estes são emitidos. A bactéria pode sobreviver como residente na raiz, hipocótilo, folhas cotiledonares e definitivas até pelo menos 30 dias após o semeio, sem necessariamente causar sintomas.Transmission of Xanthomonas vesicatoria by seeds is one of the major sources of inoculum for development of epidemic bacterial spot. The aim in this work

  13. Sobrevivência de Xanthomonas axonopodis pv. manihotis em manipueira sob condições ambientais Survival of Xanthomonas axonopodis pv. manihotis in "manipueira" under environmental conditions

    Directory of Open Access Journals (Sweden)

    Gustavo de Faria Theodoro

    2002-07-01

    Full Text Available O objetivo deste trabalho foi avaliar a sobrevivência de um isolado de Xanthomonas axonopodis pv. manihotis (Xam, resistente ao sulfato de estreptomicina, em manipueira incubada em condições ambientais, em três épocas (março, julho e outubro de 2000. Foram utilizados um meio de cultura semi-seletivo para o isolamento de X. axonopodis pv. manihotis e a técnica de reação de polimerase em cadeia (PCR ou de amplificação biológica (BIO-PCR. Foram determinados o pH e a acidez total da manipueira durante o período de incubação estudado. O isolado sobreviveu por um período inferior a 24 horas, nas três épocas do ano. A técnica de PCR ou BIO-PCR não foi eficaz em monitorar a sobrevivência do isolado em manipueira, pois apresentou resultados contraditórios e não confiáveis. Observou-se queda do pH e aumento da acidez total da manipueira incubada nas condições estudadas, que pode explicar o comportamento da sobrevivência de Xam em manipueira.The objective of this work was to evaluate the survival of a Xanthomonas axonopodis pv. manihotis (Xam strain, resistant to streptomycin sulfate, in "manipueira" (cassava residue incubated under environmental conditions, in three periods of the year (March, July and October 2000. A semi-selective culture medium and the polymerase chain reaction (PCR or biological amplification (BIO-PCR methods were used. The pH and the total acidity of the "manipueira" were determined during the incubation period. The strain survived less than 24 hours in the three periods of the year. The PCR or BIO-PCR method was not effective in monitoring the strain survival in "manipueira", as it showed contradictory and unreliable results. An increase in total acidity and a decrease in pH of the "manipueira" were observed, explaining the survival behavior of Xam strain.

  14. Science Letters:Differentiation of xanthomonads causing the bacterial leaf spot of poinsettia in China from the pathotype strain of Xanthomonas axonopodis pv. Poinsettiicola

    Institute of Scientific and Technical Information of China (English)

    LI Bin; XIE Guan-lin; SWINGS J.

    2005-01-01

    In October 2003, a new bacterial disease with symptoms similar to those caused by Xanthomonas axonopodis pv.poinsettiicola was observed on poinsettia leaves at a flower nursery in Zhejiang Province of China. Three Xanthomonas strains were isolated from infected plants and classified as X. axonopodis. They were differentiated from the pathotype strain LMG849 of X. axonopodis pv. poinsettiicola causing bacterial leaf spot of poinsettia by comparison of pathogenicity, substrate utilization and BOX-PCR genomic fingerprints.

  15. Study of the thermal degradation of citrus seeds

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Montoya, V. [Centro de Quimica, Instituto de Ciencias, Universidad Autonoma de Puebla, Apdo. Postal J-55, Puebla 72570, Pue (Mexico); Instituto Nacional del Carbon, CSIC, Apartado 73, E-33080 Oviedo (Spain); Montes-Moran, M.A. [Instituto Nacional del Carbon, CSIC, Apartado 73, E-33080 Oviedo (Spain); Elizalde-Gonzalez, M.P. [Centro de Quimica, Instituto de Ciencias, Universidad Autonoma de Puebla, Apdo. Postal J-55, Puebla 72570, Pue (Mexico)

    2009-09-15

    The citrus seeds are one of the principal residues in the juice industry and their utilization can decrease significantly the problems of their final disposal. In this work the thermal degradation of three Mexican citrus seeds: orange (Citrus sinensis), lemon (Citrus Limon) and grapefruit (Citrus paradisi) was studied in nitrogen atmosphere. The two components (embryo and husk) of the seeds were characterized separately. The results showed that the thermal effects are very similar between the three embryos and the three husks. The embryos show higher degradability, superior content of nitrogen and higher heating value than the husks. The thermal degradation of the components of the three seeds is completed at 600 C and it is considered to be a global process derived from the decomposition of their principal components (cellulose, hemicellulose and lignin). The results suggest that mixing the three entire seeds will not lead to a severe deviation from their individual thermal behavior and that the industry could apply them for carbonization purposes. (author)

  16. Identification of photoperception and light signal transduction pathways in citrus

    Directory of Open Access Journals (Sweden)

    Vera Quecini

    2007-01-01

    Full Text Available Studies employing model species have elucidated several aspects of photoperception and light signal transduction that control plant development. However, the information available for economically important crops is scarce. Citrus genome databases of expressed sequence tags (EST were investigated in order to identify genes coding for functionally characterized proteins responsible for light-regulated developmental control in model plants. Approximately 176,200 EST sequences from 53 libraries were queried and all bona fide and putative photoreceptor gene families were found in citrus species. We have identified 53 orthologs for several families of transcriptional regulators and cytoplasmic proteins mediating photoreceptor-induced responses although some important Arabidopsis phytochrome- and cryptochrome-signaling components are absent from citrus sequence databases. The main gene families responsible for phototropin-mediated signal transduction were present in citrus transcriptome, including general regulatory factors (14-3-3 proteins, scaffolding elements and auxin-responsive transcription factors and transporters. A working model of light perception, signal transduction and response-eliciting in citrus is proposed based on the identified key components. These results demonstrate the power of comparative genomics between model systems and economically important crop species to elucidate several aspects of plant physiology and metabolism.

  17. Chlorophyll Fluorescence Imaging Uncovers Photosynthetic Fingerprint of Citrus Huanglongbing

    Directory of Open Access Journals (Sweden)

    Haiyan Cen

    2017-08-01

    Full Text Available Huanglongbing (HLB is one of the most destructive diseases of citrus, which has posed a serious threat to the global citrus production. This research was aimed to explore the use of chlorophyll fluorescence imaging combined with feature selection to characterize and detect the HLB disease. Chlorophyll fluorescence images of citrus leaf samples were measured by an in-house chlorophyll fluorescence imaging system. The commonly used chlorophyll fluorescence parameters provided the first screening of HLB disease. To further explore the photosynthetic fingerprint of HLB infected leaves, three feature selection methods combined with the supervised classifiers were employed to identify the unique fluorescence signature of HLB and perform the three-class classification (i.e., healthy, HLB infected, and nutrient deficient leaves. Unlike the commonly used fluorescence parameters, this novel data-driven approach by using the combination of the mean fluorescence parameters and image features gave the best classification performance with the accuracy of 97%, and presented a better interpretation for the spatial heterogeneity of photochemical and non-photochemical components in HLB infected citrus leaves. These results imply the potential of the proposed approach for the citrus HLB disease diagnosis, and also provide a valuable insight for the photosynthetic response to the HLB disease.

  18. Chlorophyll Fluorescence Imaging Uncovers Photosynthetic Fingerprint of Citrus Huanglongbing.

    Science.gov (United States)

    Cen, Haiyan; Weng, Haiyong; Yao, Jieni; He, Mubin; Lv, Jingwen; Hua, Shijia; Li, Hongye; He, Yong

    2017-01-01

    Huanglongbing (HLB) is one of the most destructive diseases of citrus, which has posed a serious threat to the global citrus production. This research was aimed to explore the use of chlorophyll fluorescence imaging combined with feature selection to characterize and detect the HLB disease. Chlorophyll fluorescence images of citrus leaf samples were measured by an in-house chlorophyll fluorescence imaging system. The commonly used chlorophyll fluorescence parameters provided the first screening of HLB disease. To further explore the photosynthetic fingerprint of HLB infected leaves, three feature selection methods combined with the supervised classifiers were employed to identify the unique fluorescence signature of HLB and perform the three-class classification (i.e., healthy, HLB infected, and nutrient deficient leaves). Unlike the commonly used fluorescence parameters, this novel data-driven approach by using the combination of the mean fluorescence parameters and image features gave the best classification performance with the accuracy of 97%, and presented a better interpretation for the spatial heterogeneity of photochemical and non-photochemical components in HLB infected citrus leaves. These results imply the potential of the proposed approach for the citrus HLB disease diagnosis, and also provide a valuable insight for the photosynthetic response to the HLB disease.

  19. Technological Advances in Huanglongbing (HLB or Citrus Greening Disease Management

    Directory of Open Access Journals (Sweden)

    Krishna Prasad Paudyal

    2015-12-01

    Full Text Available Huanglongbing (HLB, previously citrus greening disease, is the most destructive of citrus species causing major threat to the world citrus industry. The disease was reported from China in 1919 and now known to occur in more than 40 different countries of Asia, Africa, South and North America. Three species of gram negative bacterium namely Candidatus Liberibacter asiaticus, Candidatus Liberibacter africanus and Candidatus Liberibacter americanus are the casual organisms of HLB, respectively prevailing in the continent of Asia, Africa and South America. It is one of the most extensively researched subjects in citriculture world. HLB was detected in 2004 and 2005, respectively in San Paulo of Brazil and Florida of USA: the two leading citrus production hub of the world causing huge economic loss within 5 years of first detection. Since then research on HLB detection and management was further accelerated in American continents. This paper presents the scientific advancement made on detection, spread, economic losses caused by HLB in different parts of the world and controlling management strategies. Remarkable achievements have been made on HLB detection techniques including iodine test, qPCR and more recently in spectroscopy. While efforts are being made to develop resistance varieties using conventional and biotechnological tools management strategy which includes reduction of inoculums source, vector control and replant with disease-free planting materials still remains major option for HLB control. Citrus intercropping with guava have shown promising results for vector reduction.

  20. Investigation of a Quadruplex-Forming Repeat Sequence Highly Enriched in Xanthomonas and Nostoc sp.

    Directory of Open Access Journals (Sweden)

    Charlotte Rehm

    Full Text Available In prokaryotes simple sequence repeats (SSRs with unit sizes of 1-5 nucleotides (nt are causative for phase and antigenic variation. Although an increased abundance of heptameric repeats was noticed in bacteria, reports about SSRs of 6-9 nt are rare. In particular G-rich repeat sequences with the propensity to fold into G-quadruplex (G4 structures have received little attention. In silico analysis of prokaryotic genomes show putative G4 forming sequences to be abundant. This report focuses on a surprisingly enriched G-rich repeat of the type GGGNATC in Xanthomonas and cyanobacteria such as Nostoc. We studied in detail the genomes of Xanthomonas campestris pv. campestris ATCC 33913 (Xcc, Xanthomonas axonopodis pv. citri str. 306 (Xac, and Nostoc sp. strain PCC7120 (Ana. In all three organisms repeats are spread all over the genome with an over-representation in non-coding regions. Extensive variation of the number of repetitive units was observed with repeat numbers ranging from two up to 26 units. However a clear preference for four units was detected. The strong bias for four units coincides with the requirement of four consecutive G-tracts for G4 formation. Evidence for G4 formation of the consensus repeat sequences was found in biophysical studies utilizing CD spectroscopy. The G-rich repeats are preferably located between aligned open reading frames (ORFs and are under-represented in coding regions or between divergent ORFs. The G-rich repeats are preferentially located within a distance of 50 bp upstream of an ORF on the anti-sense strand or within 50 bp from the stop codon on the sense strand. Analysis of whole transcriptome sequence data showed that the majority of repeat sequences are transcribed. The genetic loci in the vicinity of repeat regions show increased genomic stability. In conclusion, we introduce and characterize a special class of highly abundant and wide-spread quadruplex-forming repeat sequences in bacteria.

  1. 7 CFR 305.10 - Treatment schedules for combination treatments.

    Science.gov (United States)

    2010-01-01

    ... HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS Chemical Treatments § 305...) T203-p and T511-1, hot water and chemical dip for citrus (Rutacae) seeds for citrus canker. (1) If any... of 6.0 to 7.5. (4) Seed from regions where citrus canker occurs must be drained, dried, and...

  2. Reaction of cassava’s germoplasm to Xanthomonas axonopodis pv. manihots/ Reação de germoplasma de mandioca a Xanthomonas axonopodis pv. manihots

    Directory of Open Access Journals (Sweden)

    Benjamim de Melo

    2007-07-01

    Full Text Available The cassava is presented as an important stach source, mainly in the tropics. The bacteriosis disease caused by Xanthomonas axonopodis p.v. manihots is the most important disease of this culture and its damage can achieve 30% of the production, or even more. This work objectified to evaluate, in green house condition the reaction of “mandioca mansa” and the “mandioca brava” cassava’s germoplasma to the two isolates of Xanthomonas axonopodis p.v. manihots. Trials were developed at the Instituto de Ciências Agrárias da Universidade Federal de Uberlândia. The plants had been inoculated by seasor’s cuttings of three central leaflets in three completely opened new leaves, following by insertion of a little wood stick at the oldest leaf’s axel, using a bacterial suspension at 2x109u.f.c. mL-1. The inoculation happened at the 42nd day after planting and the evaluation at the 41st day after inoculation. The evaluation criteria were: notes of visual symptoms in the aerial part, percentages defoliation and systemic infection of the stalk. The results showed the efficiency of the evaluation criteria applied at this work for the isolates virulence study. The Uberlândia isolate was more virulent to “mandioca mansa” cassava cultivars and the Lavras isolate was more virulent to “mandioca brava” cassava cultivars. That indicates the need of using isolates from the region where the germoplasm will be cultivated. Considering the germoplasm resistance reaction analysis, both the sistemic infection precentage and the defoliation criteria presented as very effective. Oustanding behavior was observed for the Vassoura, Amarela, Vermelha and Castelinho cultivars and for the CPAC88-11 clone.A mandioca apresenta-se como importante fonte de carboidratos, principalmente nos trópicos. A bacteriose causada por Xanthomonas axonopodis p.v. manihots é a doença mais importante desta cultura e seus danos podem chegar a 30% ou mais na produção. Este

  3. Molecular detection of Xanthomonas oryzae pv.oryzae, Xanthomonas oryzae pv. oryzicola, and Burkholderia glumae in infected rice seeds and leaves

    Institute of Scientific and Technical Information of China (English)

    Wen; Lu; Luqi; Pan; Haijun; Zhao; Yulin; Jia; Yanli; Wang; Xiaoping; Yu; Xueyan; Wang

    2014-01-01

    The polymerase chain reaction(PCR) is particularly useful for plant pathogen detection. In the present study, multiplex PCR and SYBR Green real-time PCR were developed to facilitate the simultaneous detection of three important rice pathogens, Xanthomonas oryzae pv.oryzae, X. oryzae pv. oryzicola, and Burkholderia glumae. The unique PCR primer sets were designed from portions of a putative glycosyltransferase gene of X. oryzae pv. oryzae, an Avr Rxo gene of X. oryzae pv. oryzicola, and an internal transcribed spacer(ITS) sequence of B. glumae. Using a multiplex PCR assay, X. oryzae pv. oryzae, X. oryzae pv. oryzicola, and B. glumae were detected in one PCR reaction that contained the newly developed primer set mix. Using SYBR Green real-time PCR assays, X. oryzae pv. oryzae, X. oryzae pv. oryzicola, and B. glumae were detected at 1, 1, and 10 fg μL-1, respectively. These newly designed molecular assays are sensitive and could be reliable tools for pathogen detection and disease forecasting.

  4. Genomic insights into strategies used by Xanthomonas albilineans with its reduced artillery to spread within sugarcane xylem vessels

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    Pieretti Isabelle

    2012-11-01

    Full Text Available Abstract Background Xanthomonas albilineans causes leaf scald, a lethal disease of sugarcane. X. albilineans exhibits distinctive pathogenic mechanisms, ecology and taxonomy compared to other species of Xanthomonas. For example, this species produces a potent DNA gyrase inhibitor called albicidin that is largely responsible for inducing disease symptoms; its habitat is limited to xylem; and the species exhibits large variability. A first manuscript on the complete genome sequence of the highly pathogenic X. albilineans strain GPE PC73 focused exclusively on distinctive genomic features shared with Xylella fastidiosa—another xylem-limited Xanthomonadaceae. The present manuscript on the same genome sequence aims to describe all other pathogenicity-related genomic features of X. albilineans, and to compare, using suppression subtractive hybridization (SSH, genomic features of two strains differing in pathogenicity. Results Comparative genomic analyses showed that most of the known pathogenicity factors from other Xanthomonas species are conserved in X. albilineans, with the notable absence of two major determinants of the “artillery” of other plant pathogenic species of Xanthomonas: the xanthan gum biosynthesis gene cluster, and the type III secretion system Hrp (hypersensitive response and pathogenicity. Genomic features specific to X. albilineans that may contribute to specific adaptation of this pathogen to sugarcane xylem vessels were also revealed. SSH experiments led to the identification of 20 genes common to three highly pathogenic strains but missing in a less pathogenic strain. These 20 genes, which include four ABC transporter genes, a methyl-accepting chemotaxis protein gene and an oxidoreductase gene, could play a key role in pathogenicity. With the exception of hypothetical proteins revealed by our comparative genomic analyses and SSH experiments, no genes potentially involved in any offensive or counter-defensive mechanism

  5. Metalized polyethylene mulch to repel Asian citrus psyllid, slow spread of huanglongbing and improve growth of new citrus plantings.

    Science.gov (United States)

    Croxton, Scott D; Stansly, Philip A

    2014-02-01

    Greening or huanglongbing (HLB) is a debilitating disease of citrus caused by Candidatus Liberibactor asiaticus and transmitted by the Asian citrus psyllid (ACP), Diaphorina citri. HLB now occurs worldwide in all major citrus growing regions except the Mediterranean and Australia. Management relies principally on insecticidal control of the ACP vector, but is insufficient, even for young trees which are most susceptible to the disease. We tested the ability of metalized polyethylene mulch to repel adult ACP as well as effects on incidence of HLB and early tree growth. Metalized mulch significantly reduced ACP populations and HLB incidence compared to whiteface mulch or bare ground. In addition, metalized mulch, together with the associated drip irrigation and fertigation system, increased soil moisture, reduced weed pressure, and increased tree growth rate. Metalized mulch slows spread of ACP and therefore HLB pressure on young citrus trees. Metalized mulch can thereby augment current control measures for young trees based primarily on systemic insecticides. Additional costs could be compensated for by increased tree growth rate which would shorten time to crop profitability. These advantages make a compelling case for large-scale trials using metalized mulch in young citrus plantings threatened by HLB. © 2013 Society of Chemical Industry.

  6. Volatile constituents of redblush grapefruit (Citrus paradisi) and pummelo (Citrus grandis) peel essential oils from Kenya.

    Science.gov (United States)

    Njoroge, Simon Muhoho; Koaze, Hiroshi; Karanja, Paul Nyota; Sawamura, Masayoshi

    2005-12-14

    The volatile constituents of cold-pressed peel essential oils of redblush grapefruit (Citrus paradisi Macfadyen forma Redblush) and pummelo (Citrus grandis Osbeck) from the same locality in Kenya were determined by GC and GC-MS. A total of 67 and 52 compounds, amounting to 97.9 and 98.8% of the two oils, respectively, were identified. Monoterpene hydrocarbons constituted 93.3 and 97.5% in the oils, respectively, with limonene (91.1 and 94.8%), alpha-terpinene (1.3 and 1.8%), and alpha-pinene (0.5%) as the main compounds. Sesquiterpene hydrocarbons constituted 0.4% in each oil. The notable compounds were beta-caryophyllene, alpha-cubebene, and (E,E)-alpha-farnesene. Oxygenated compounds constituted 4.2 and 2.0% of the redblush grapefruit and pummelo oils, respectively, out of which carbonyl compounds (2.0 and 1.3%), alcohols (1.4 and 0.3%), and esters (0.7 and 0.4%) were the major groups. Heptyl acetate, octanal, decanal, citronellal, and (Z)-carvone were the main constituents (0.1-0.5%). Perillene, (E)-carveol, and perillyl acetate occurred in the redblush grapefruit but were absent from the pummelo oil. Nootkatone, alpha- and beta-sinensal, methyl-N-methylanthranilate, and (Z,E)-farnesol were prominent in both oils.

  7. Analysis of SSR in Citrus Sequences from EMBL Database

    Institute of Scientific and Technical Information of China (English)

    MENG Hai-jun; CAO Qing-qin; HU Zhi-yong; LIU Gao-ping; CHENG Yun-jiang; DENG Xiu-xin

    2005-01-01

    Abundance of simple sequence repeat (SSR) in Citrus sequences from EMBL database was investigated by using computer program MISA (MIcroSAtellite), which aimed to provide useful information for the development of SSR markers.Among 32 896 sequences of Citrus, 4987 SSRs were found in 4167 sequences and the average distance between SSRs was approximately 3.5 kb. Mononucleotide repeats (50.6%) were the most abundant repeats. And di-, tri-, tetra-, penta- and hexa-nucleotide repeats were 22.8, 25.2, 1, 0.08, and 0.36%, respectively. The most abundant motif was A/T followed in descending order by AG/CT, AC/GT, AT/TA. AAT/ATT, AAG/CTT, AGC/CGT, ACG/CTG and C/G. They comprised about90% of all microsatellites. Ten primer pairs were designed, and three of them produced clear visible bands among Citrus and its related genera.

  8. The push-pull strategy for citrus psyllid control.

    Science.gov (United States)

    Yan, Huaxue; Zeng, Jiwu; Zhong, Guangyan

    2015-07-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the only natural vector of Candidatus Liberibacter asiaticus that causes citrus huanglongbing (HLB), a most destructive disease of citrus. Currently, no remedial therapy exists for the disease, and so effective control of ACP is very important in curbing the transmission of the disease. The push-pull strategy should be thoroughly explored as an approach to ACP management. This mini-review summarises the current progress towards more effective repellent and attractant chemicals through investigating known repellent and attractive plants. Interactions between ACP and its host plants are also addressed, with emphasis on the possible involvement of the host biochemicals in attracting the insect. Potential ways to increase the effectiveness of the pull-push strategy are briefly discussed. It is expected that the pull-push strategy will be gradually developed following more extensive research.

  9. Selection processes in a citrus hybrid population using RAPD markers

    Directory of Open Access Journals (Sweden)

    Oliveira Roberto Pedroso de

    2003-01-01

    Full Text Available The objective of this work was to evaluate the processes of selection in a citrus hybrid population using segregation analysis of RAPD markers. The segregation of 123 RAPD markers between 'Cravo' mandarin (Citrus reticulata Blanco and 'Pêra' sweet orange (C. sinensis (L. Osbeck was analysed in a F1 progeny of 94 hybrids. Genetic composition, diversity, heterozygosity, differences in chromosomal structure and the presence of deleterious recessive genes are discussed based on the segregation ratios obtained. A high percentage of markers had a skeweness of the 1:1 expected segregation ratio in the F1 population. Many markers showed a 3:1 segregation ratio in both varieties and 1:3 in 'Pêra' sweet orange, probably due to directional selection processes. The distribution analysis of the frequencies of the segregant markers in a hybrid population is a simple method which allows a better understanding of the genetics of citrus group.

  10. The IDA peptide controls abscission in Arabidopsis and Citrus

    Directory of Open Access Journals (Sweden)

    Leandro H Estornell

    2015-11-01

    Full Text Available Organ abscission is an important process in plant development and reproduction. During abscission, changes in cellular adhesion of specialised abscission zone (AZ cells ensure the detachment of infected organs or those no longer serving a function to the plant. In addition, abscission also plays an important role in the release of ripe fruits. Different plant species display distinct patterns and timing of organ shedding, most likely adapted during evolution to their diverse life styles. However, it appears that key regulators of cell separation may have conserved function in different plant species. Here we investigate the functional conservation of the citrus orthologue of the Arabidopsis peptide ligand INFLORESCENCE DEFICIENT IN ABSCISSION (AtIDA, controlling floral organ abscission. We discuss the possible implications of modifying the citrus IDA orthologue for citrus fruit production.

  11. Enhanced Acquisition Rates of 'Candidatus Liberibacter asiaticus' by the Asian Citrus Psyllid (Hemiptera: Liviidae) in the Presence of Vegetative Flush Growth in Citrus.

    Science.gov (United States)

    Sétamou, Mamoudou; Alabi, Olufemi J; Kunta, Madhurababu; Jifon, John L; da Graça, John V

    2016-10-01

    The Asian citrus psyllid preferentially feeds and exclusively reproduces on young, newly emerged flush shoots of citrus. Asian citrus psyllid nymphs feed and complete their life stages on these flush shoots. Recent studies conducted under greenhouse conditions have shown that the transmission rates of 'Candidatus Liberibacter asiaticus' (CLas), the putative causal agent of huanglongbing disease of citrus, are enhanced when flush shoots are present. However, it is unclear if CLas acquisition by migrant adult Asian citrus psyllids is similarly enhanced. To address this knowledge gap, cohorts of Asian citrus psyllid adults were allowed 1-wk acquisition access period (AAP) on flushing and nonflushing shoots of qPCR-tested symptomatic (CLas+) and asymptomatic (CLas-) 10-yr-old sweet orange trees under field conditions. After the AAP, they were tested for CLas by qPCR. Progeny Asian citrus psyllid adults that emerged 4 wk post-AAP were similarly retrieved and tested. Eighty percent of flushing and 30% of nonflushing CLas+ trees produced infective Asian citrus psyllid adults, indicating that flush shoots have greater potential to be inoculum sources for CLas acquisition. Concomitantly, 21.1% and 6.0% infective adults were retrieved, respectively, from flushing and nonflushing CLas+ trees, indicating that Asian citrus psyllid adults acquire CLas more efficiently from flush shoots relative to mature shoots. In addition, 12.1% of infective Asian citrus psyllid adult progeny were obtained from 70% of flushing CLas+ trees. Significantly lower mean Ct values were also obtained from infective adults retrieved from flushing relative to nonflushing trees. The results underscore the role of flush shoots in CLas acquisition and the need to protect citrus trees from Asian citrus psyllid infestations during flush cycles.

  12. Organic Acid Concentrations and the Relative Enzymatic Changes During the Development of the Citrus Fruits

    Institute of Scientific and Technical Information of China (English)

    LUO An-cai; YANG Xiao-hong; DENG Ying-yi; LI Chun-fan; XIANG Ke-shu; LI Dao-gao

    2003-01-01

    Seasonal changes in enzyme activities and citrate concentration during the development of citrus fruits were investigated. The result showed that the organic acid concentrations reached a peak in the 100 - 130days after anthesis and gradually declined during later stages of fruit maturation in most varieties of citrus,but declined only slightly thereafter in lemon [Citrus lin on (L.) Burm]; there is no relation between the activity of citrate synthetase(CS) and the different acid concentration in different citrus fruits; the increase of the activity of the cytosolic aconitase in the late period of the development of citrus fruits accelerated the degradation of citric acid in citrus fruits; the higher the activity of phosphoenolpyruvate carboxylase(PEPC) and the ratio of NAD-dependent isocitrate hydrogenase(PEPC/NAD-IDH- ), the more the concentrations of organic acids in citrus fruit.

  13. Gluconacetobacter diazotrophicus Elicits a Sugarcane Defense Response Against a Pathogenic Bacteria Xanthomonas albilineans

    Science.gov (United States)

    Vinagre, Fabiano; Estevez, Yandi; Bernal, Aydiloide; Perez, Juana; Cavalcanti, Janaina; Santana, Ignacio; Hemerly, Adriana S

    2006-01-01

    A new role for the plant growth-promoting nitrogen-fixing endophytic bacteria Gluconacetobacter diazotrophicus has been identified and characterized while it is involved in the sugarcane-Xanthomonas albilineans pathogenic interactions. Living G.diazotrophicus possess and/or produce elicitor molecules which activate the sugarcane defense response resulting in the plant resistance to X. albilineans, in this particular case controlling the pathogen transmission to emerging agamic shoots. A total of 47 differentially expressed transcript derived fragments (TDFs) were identified by cDNA-AFLP. Transcripts showed significant homologies to genes of the ethylene signaling pathway (26%), proteins regulates by auxins (9%), β-1,3 Glucanase proteins (6%) and ubiquitin genes (4%), all major signaling mechanisms. Results point toward a form of induction of systemic resistance in sugarcane-G. diazotrophicus interactions which protect the plant against X. albilineans attack. PMID:19516988

  14. Effector Diversification Contributes to Xanthomonas oryzae pv. oryzae Phenotypic Adaptation in a Semi-Isolated Environment

    Science.gov (United States)

    Quibod, Ian Lorenzo; Perez-Quintero, Alvaro; Booher, Nicholas J.; Dossa, Gerbert S.; Grande, Genelou; Szurek, Boris; Vera Cruz, Casiana; Bogdanove, Adam J.; Oliva, Ricardo

    2016-01-01

    Understanding the processes that shaped contemporary pathogen populations in agricultural landscapes is quite important to define appropriate management strategies and to support crop improvement efforts. Here, we took advantage of an historical record to examine the adaptation pathway of the rice pathogen Xanthomonas oryzae pv. oryzae (Xoo) in a semi-isolated environment represented in the Philippine archipelago. By comparing genomes of key Xoo groups we showed that modern populations derived from three Asian lineages. We also showed that diversification of virulence factors occurred within each lineage, most likely driven by host adaptation, and it was essential to shape contemporary pathogen races. This finding is particularly important because it expands our understanding of pathogen adaptation to modern agriculture. PMID:27667260

  15. Functional Analysis of the Ferric Uptake Regulator Gene fur in Xanthomonas vesicatoria.

    Science.gov (United States)

    Liu, Huiqin; Dong, Chunling; Zhao, Tingchang; Han, Jucai; Wang, Tieling; Wen, Xiangzhen; Huang, Qi

    2016-01-01

    Iron is essential for the growth and survival of many organisms. Intracellular iron homeostasis must be maintained for cell survival and protection against iron toxicity. The ferric uptake regulator protein (Fur) regulates the high-affinity ferric uptake system in many bacteria. To investigate the function of the fur gene in Xanthomonas vesicatoria (Xv), we generated a fur mutant strain, fur-m, by site-directed mutagenesis. Whereas siderophore production increased in the Xv fur mutant, extracellular polysaccharide production, biofilm formation, swimming ability and quorum sensing signals were all significantly decreased. The fur mutant also had significantly reduced virulence in tomato leaves. The above-mentioned phenotypes significantly recovered when the Xv fur mutation allele was complemented with a wild-type fur gene. Thus, Fur either negatively or positively regulates multiple important physiological functions in Xv.

  16. Gluconacetobacter diazotrophicus Elicits a Sugarcane Defense Response Against a Pathogenic Bacteria Xanthomonas albilineans.

    Science.gov (United States)

    Arencibia, Ariel D; Vinagre, Fabiano; Estevez, Yandi; Bernal, Aydiloide; Perez, Juana; Cavalcanti, Janaina; Santana, Ignacio; Hemerly, Adriana S

    2006-09-01

    A new role for the plant growth-promoting nitrogen-fixing endophytic bacteria Gluconacetobacter diazotrophicus has been identified and characterized while it is involved in the sugarcane-Xanthomonas albilineans pathogenic interactions. Living G.diazotrophicus possess and/or produce elicitor molecules which activate the sugarcane defense response resulting in the plant resistance to X. albilineans, in this particular case controlling the pathogen transmission to emerging agamic shoots. A total of 47 differentially expressed transcript derived fragments (TDFs) were identified by cDNA-AFLP. Transcripts showed significant homologies to genes of the ethylene signaling pathway (26%), proteins regulates by auxins (9%), beta-1,3 Glucanase proteins (6%) and ubiquitin genes (4%), all major signaling mechanisms. Results point toward a form of induction of systemic resistance in sugarcane-G. diazotrophicus interactions which protect the plant against X. albilineans attack.

  17. Meio semi-seletivo para isolamento de Xanthomonas campestris pv. viticola

    Directory of Open Access Journals (Sweden)

    Peixoto Ana Rosa

    2006-01-01

    Full Text Available O cancro bacteriano causado por Xanthomonas campestris pv. viticola é a fitobacteriose mais importante da videira no Submédio São Francisco. O isolamento de X. campestris pv. viticola de tecidos vegetais infectados é dificultado pela presença de contaminantes bacterianos, entre os quais Microbacterium barkeri. Objetivando-se a formulação de meio de cultura semi-seletivo, 22 isolados de X. campestris pv. viticola foram testados com relação a 30 antibióticos. O meio semi-seletivo NYDAM (extrato de carne 3, peptona 5, glicose 10, extrato de levedura 5, ágar 18 e ampicilina 0,1 em g L-1 inibiu M. barkeri e bactérias fitopatogênicas podendo ser utilizado para isolar X. campestris pv. viticola de hospedeiros com infecção natural em campo.

  18. Distinct gene expression profile of Xanthomonas retroflexus engaged in synergistic multispecies biofilm formation

    DEFF Research Database (Denmark)

    Hansen, Lea Benedicte Skov; Ren, Dawei; Burmølle, Mette;

    2017-01-01

    It is well known that bacteria often exist in naturally formed multispecies biofilms. Within these biofilms, interspecies interactions seem to have an important role in ecological processes. Little is known about the effects of interspecies interactions on gene expression in these multispecies...... biofilms. This study presents a comparative gene expression analysis of the Xanthomonas retroflexus transcriptome when grown in a single-species biofilm and in dual-and four-species consortia with Stenotrophomonas rhizophila, Microbacterium oxydans and Paenibacillus amylolyticus. The results revealed...... complex interdependent interaction patterns in the multispecies biofilms. Many of the regulated functions are related to interactions with the external environment and suggest a high phenotypic plasticity in response to coexistence with other species. Furthermore, the changed expression of genes involved...

  19. Surface layers of Xanthomonas malvacearum, the cause of bacterial blight of cotton.

    Science.gov (United States)

    Verma, J P; Formanek, H

    1981-01-01

    Mureins were isolated from two strains of Xanthomonas malvacearum, a phytopathogenic bacterium causing bacterial blight of cotton. The purity of murein was 70-95 % and the amino acid and amino sugar components (glutamic acid, alanina, meso-disminopimelic acid, muramic acid and glucosamine) were present at the molar ratio of 1:1.9:1:l.12.0.85. The bacterium secreted a copious amount of slime which masked itd surface structure. The slime was composed of densley interwoven network of filamentous material originating from the cell surface and extended into the medium without and discernable boundary. The slime was secreted through surface layers pores by force, giving the effect of a spray or jet. Slime also played a role in chain formatin of baterial cells.

  20. Effect of virulence and serial transfers of Xanthomonas campestris on xanthan gum production

    Directory of Open Access Journals (Sweden)

    Nitschke Marcia

    2000-01-01

    Full Text Available The virulence of six Xanthomonas campestris isolates was evaluated using the percentage of lesion area of leaves in Brassica oleraceae host plant, compared to diameter of colonies, xanthan production and gum viscosity. In terms of virulence, the isolates belonged to two statistically different groups: isolates B, UPF and C7 showed values between 52 and 69%, while isolates CF, C and strain B-1459 gave 0-30% of lesion area. Final xanthan concentration, gum viscosity and colony diameter did not correlate with virulence calculated by percentage of lesion area, showing that this parameter is not a good criterium for selection of potential xanthan producer isolates. Serial transfers of X. campestris isolates in host plant did not show a significant effect on "in vitro" production of xanthan or on viscosity levels, suggesting that the increasing interaction between plant and bacteria did not stimulate the increase in xanthan production and viscosity.

  1. Estrategias para diferenciar xanthomonas campestris pv. phaseoli con sales inorgánicas

    Directory of Open Access Journals (Sweden)

    Mildred Zapata

    2001-01-01

    Full Text Available Colonias de Xanthomonas campestris pv. phaseoli (Xcp aisladas de hojas de habichuelas con síntomas de tizón común en Puerto Rico, República Dominicana y Costa Rica fueron caracterizadas como patogénicas en hojas de Phaseolus vulgaris. Sin embargo, éstas fueron clasificadas en los patovares phaseoli, vesicatoria, carotae y xanthosoma por el sistema Biolog. Las cepas de Xcp crecidas en 2, 3, 5-Trifenil cloruro de tetrazolio (TTC mostraron colonias convexas, brillosas, lisas y de color rojo en diferentes tamaños. TTC fue reducido por las cepas de Xcp a un pigmento rojo intenso, un formazán de trifenilo. No se encontraron diferencias en virulencia y tipos de colonias en las cepas identificadas por pruebas de patogenicidad como Xcp. Por otro lado, hubo diferencias en el tipo de colonia en cultivos bacterianos identificados como: Pseudomonas cissicola, P. fulva, Corynebacterium, Rhodococcus, y Shingomonas

  2. Functional Analysis of the Ferric Uptake Regulator Gene fur in Xanthomonas vesicatoria.

    Directory of Open Access Journals (Sweden)

    Huiqin Liu

    Full Text Available Iron is essential for the growth and survival of many organisms. Intracellular iron homeostasis must be maintained for cell survival and protection against iron toxicity. The ferric uptake regulator protein (Fur regulates the high-affinity ferric uptake system in many bacteria. To investigate the function of the fur gene in Xanthomonas vesicatoria (Xv, we generated a fur mutant strain, fur-m, by site-directed mutagenesis. Whereas siderophore production increased in the Xv fur mutant, extracellular polysaccharide production, biofilm formation, swimming ability and quorum sensing signals were all significantly decreased. The fur mutant also had significantly reduced virulence in tomato leaves. The above-mentioned phenotypes significantly recovered when the Xv fur mutation allele was complemented with a wild-type fur gene. Thus, Fur either negatively or positively regulates multiple important physiological functions in Xv.

  3. Preservation of Xanthomonas campestris on agar slopes: effects on xanthan production

    Energy Technology Data Exchange (ETDEWEB)

    Galindo, E. (Universidad Nacional Autonoma de Mexico, Cuernavaca (Mexico). Dept. de Bioingenieria); Salcedo, G. (Universidad Nacional Autonoma de Mexico, Cuernavaca (Mexico). Dept. de Bioingenieria); Ramirez, M.E. (Universidad Nacional Autonoma de Mexico, Cuernavaca (Mexico). Dept. de Bioingenieria)

    1994-01-01

    Xanthomonas campestris NRRL B-1459 and a variant E2, when preserved on agar slopes (transferred monthly) over 11 months did not deteriorate in their ability to produce xanthan in quantity and quality, as determined by culture in 500-ml baffled flasks. Variations between 8 and 14% (with respect to the average) in the final xanthan concentration were observed for the E2 and B-1459 strains, respectively. A wide range of final viscosities was obtained; these were consistent with the changes in gum concentration. Differences were more likely associated with differences in fermentation kinetics rather than being inherent to the strains. The rheological quality of both polysaccharides was relatively constant throughout the time of culture maintenance. Preservation of these bacteria on agar slopes was an adequate method, in contrast to previous reports. In the period studied, strain E2 produced higher gum titres and slightly lower gum quality compared to strain B-1459. (orig.)

  4. Purification and properties of an unusual UDP-glucose dehydrogenase, NADPH-dependent, from Xanthomonas albilineans.

    Science.gov (United States)

    Blanch, María; Legaz, María-Estrella; Vicente, C

    2008-01-01

    Xanthomonas albilineans produces a UDP-glucose dehydrogenase growing on sucrose. The enzyme oxidizes UDP-glucose to UDP-glucuronic acid by using molecular oxygen and NADPH. Kinetics of enzymatic oxydation of NADPH is linearly dependent on the amount of oxygen supplied. The enzyme has been purified at homogeneity. The value of pI of the purified enzyme is 8.98 and its molecular mass has been estimated as about 14 kDa. The enzyme shows a michaelian kinetics for UDP-glucose concentrations. The value of K(m) for UDP-glucose is 0.87 mM and 0.26 mM for NADPH, although the enzyme has three different sites to interact with NADPH. The enzyme is inhibited by UDP-glucose concentrations higher than 1.3 mM. N-Terminal sequence has been determined as IQPYNH.

  5. In Vitro Propagation of Citrus Rootstocks

    Directory of Open Access Journals (Sweden)

    Suneel SHARMA

    2009-06-01

    Full Text Available Present investigation was conducted to standardize a protocol for in-vitro propagation of citrus rootstocks viz. Rough lemon, Cleopatra mandarin Pectinifera and Troyer citrange. The shoot tip explant was found better for callus induction of these rootstocks than the nodal segment. Maximum callus formation (40.0% and 23.3% of shoot tip explants was obtained in Cleopatra mandarin, Pectinifera, and Rough lemon and Troyer citrange, respectively in treatment MS basal media + 0.5mg/l Kin, 2.0mg/l NAA, and 2.0mg/l 2, 4-D. Furthermore, the maximum number of shoots per explant was obtained through the callus in Pectinifera, Rough lemon and Cleopatra mandarin in MS basal media + BAP 1mg/l. Maximum rooting of shoots (1.11% was noted in rootstock Rough lemon followed by Cleopatra mandarin for the � MS media supplemented with 10mg/l IBA. Although the callus development and bud proliferation was recorded in rootstock Troyer citrange however, shoot and root formation did not occur. The potting media consisting of soil, sand and FYM in the ratio of 1:1:1 by volume was better with maximum survival rate of hardened plants six weeks after transferring to the pots under greenhouse for Rough lemon followed by Pectinifera and Cleopatra mandarin rootstock.

  6. Behavioral effects of Citrus limon in rats.

    Science.gov (United States)

    Khan, Rafeeq Alam; Riaz, Azra

    2015-04-01

    Anxiety and depression are increasing worldwide, however these disorders may be managed by making healthier changes is dietary pattern, since there are evidences that diet rich in antioxidants and vitamins help reduce anxiety and depression. Hence present study was designed to evaluate the behavioral effects of Citrus limon in rats at three different doses i.e. 0.2, 0.4 and 0.6 ml/kg considered as low, moderate and high doses. Anxiolytic and antidepressant activities were specifically assessed twice during 15 days using open field test, elevated plus maze and forced swimming test. In open field test C. limon, revealed increase in distance travelled, number of central entries and number of rearing's at moderate dose, while in the elevated plus maze, number of open arm entries were found to be increased. Whereas in forced swimming test, there was decrease in duration of immobility and increase in duration of climbing. Thus results of present study suggest that C. limon at moderate dose have anxiolytic effect.

  7. An RNA-Seq-based reference transcriptome for Citrus.

    Science.gov (United States)

    Terol, Javier; Tadeo, Francisco; Ventimilla, Daniel; Talon, Manuel

    2016-03-01

    Previous RNA-Seq studies in citrus have been focused on physiological processes relevant to fruit quality and productivity of the major species, especially sweet orange. Less attention has been paid to vegetative or reproductive tissues, while most Citrus species have never been analysed. In this work, we characterized the transcriptome of vegetative and reproductive tissues from 12 Citrus species from all main phylogenetic groups. Our aims were to acquire a complete view of the citrus transcriptome landscape, to improve previous functional annotations and to obtain genetic markers associated with genes of agronomic interest. 28 samples were used for RNA-Seq analysis, obtained from 12 Citrus species: C. medica, C. aurantifolia, C. limon, C. bergamia, C. clementina, C. deliciosa, C. reshni, C. maxima, C. paradisi, C. aurantium, C. sinensis and Poncirus trifoliata. Four different organs were analysed: root, phloem, leaf and flower. A total of 3421 million Illumina reads were produced and mapped against the reference C. clementina genome sequence. Transcript discovery pipeline revealed 3326 new genes, the number of genes with alternative splicing was increased to 19,739, and a total of 73,797 transcripts were identified. Differential expression studies between the four tissues showed that gene expression is overall related to the physiological function of the specific organs above any other variable. Variants discovery analysis revealed the presence of indels and SNPs in genes associated with fruit quality and productivity. Pivotal pathways in citrus such as those of flavonoids, flavonols, ethylene and auxin were also analysed in detail. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  8. Produção e caracterização de anticorpos policlonais contra Xanthomonas campestris pv. viticola Production and characterization of polyclonal antibodies against Xanthomonas campestris pv. viticola

    Directory of Open Access Journals (Sweden)

    João Sebastião de Paula Araujo

    2005-03-01

    Full Text Available O objetivo deste trabalho foi a produção de anticorpos policlonais contra Xanthomonas campestris pv. viticola e sua caracterização pelo método Elisa indireto. Os resultados apontaram a qualidade dos anticorpos policlonais produzidos, os quais mostraram-se altamente reativos e específicos para o patovar com potencial para ser empregado no diagnóstico da doença e em programas de certificação.The objective of this work was to produce polyclonal antibodies against Xanthomonas campestris pv. viticola and characterize these antibodies through Elisa serological indirect method. Results indicate that polyclonal antibodies produced were highly reactive against bacterial cells, showing specificity at the pathovar level and potential to be used for diagnosis and certification purposes.

  9. Genomics and transcriptomics of Xanthomonas campestris species challenge the concept of core type III effectome.

    Science.gov (United States)

    Roux, Brice; Bolot, Stéphanie; Guy, Endrick; Denancé, Nicolas; Lautier, Martine; Jardinaud, Marie-Françoise; Fischer-Le Saux, Marion; Portier, Perrine; Jacques, Marie-Agnès; Gagnevin, Lionel; Pruvost, Olivier; Lauber, Emmanuelle; Arlat, Matthieu; Carrère, Sébastien; Koebnik, Ralf; Noël, Laurent D

    2015-11-18

    The bacterial species Xanthomonas campestris infects a wide range of Brassicaceae. Specific pathovars of this species cause black rot (pv. campestris), bacterial blight of stock (pv. incanae) or bacterial leaf spot (pv. raphani). In this study, we extended the genomic coverage of the species by sequencing and annotating the genomes of strains from pathovar incanae (CFBP 1606R and CFBP 2527R), pathovar raphani (CFBP 5828R) and a pathovar formerly named barbareae (CFBP 5825R). While comparative analyses identified a large core ORFeome at the species level, the core type III effectome was limited to only three putative type III effectors (XopP, XopF1 and XopAL1). In Xanthomonas, these effector proteins are injected inside the plant cells by the type III secretion system and contribute collectively to virulence. A deep and strand-specific RNA sequencing strategy was adopted in order to experimentally refine genome annotation for strain CFBP 5828R. This approach also allowed the experimental definition of novel ORFs and non-coding RNA transcripts. Using a constitutively active allele of hrpG, a master regulator of the type III secretion system, a HrpG-dependent regulon of 141 genes co-regulated with the type III secretion system was identified. Importantly, all these genes but seven are positively regulated by HrpG and 56 of those encode components of the Hrp type III secretion system and putative effector proteins. This dataset is an important resource to mine for novel type III effector proteins as well as for bacterial genes which could contribute to pathogenicity of X. campestris.

  10. Weed Biomass and Weed Species Diversity of Juvenile Citrus Trees Intercrop with some Arable Crops

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    Patience Mojibade OLORUNMAIYE

    2012-02-01

    Full Text Available A preliminary study was carried out to evaluate the performances of eight crops in the intercrop of citrus with arable crops at the National Horticultural Research Institute (NIHORT Ibadan, Nigeria. Eight arable crops: maize, cucumber, sweet potato, Corchorus olitorius, large green, grain amaranth, Mucuna pruriens var. utilis, and groundnut were intercropped with young citrus trees in the early planting season of 2010 with sole citrus as control. The experiment was laid out in a completely randomized block design with three replicates. Data were collected on weed flora, weed density and weed dry weight. Results showed that the relative frequencies of weeds in all the plots were less than 4% at both 6 and 9WAP. Gomphrena celosoides, Oldenlandia corymbosa and Tridax procumbens were most preponderant in appearing in all the plots. Tridax procumbens had a consistent relative frequency (2.34% in all the plots except in citrus/maize plot (0.78% at 9 WAP. Significantly lower broadleaf weed densities were obtained in citrus/sweet potato, citrus/large green, control plot and citrus/cucumber (28.67, 45.00, 50.00 and 76.33 m-2 respectively than in citrus/groundnut plot (143.00 m-2. Similarly, significantly lower grass weed densities were produced in citrus/Mucuna and citrus/sweet potato (0.33 m-2 each plots than the control plot (11.33 m-2. Whereas citrus/corchorus plot produced significantly lower broadleaf weed dry weight (37.59 g m-2 than citrus/Mucuna plot (126.47 g m-2 at 3WAP, citrus/large green plot (16.15 g m-2 and citrus/groundnut plot (123.25 g m-2 followed the same trend at 6 WAP. Sedges dry weights were less than 7 g m-2 in all the plots compared with control plot.

  11. Weed Biomass and Weed Species Diversity of Juvenile Citrus Trees Intercrop with some Arable Crops

    Directory of Open Access Journals (Sweden)

    Patience Mojibade OLORUNMAIYE

    2012-02-01

    Full Text Available A preliminary study was carried out to evaluate the performances of eight crops in the intercrop of citrus with arable crops at the National Horticultural Research Institute (NIHORT Ibadan, Nigeria. Eight arable crops: maize, cucumber, sweet potato, Corchorus olitorius, large green, grain amaranth, Mucuna pruriens var. utilis, and groundnut were intercropped with young citrus trees in the early planting season of 2010 with sole citrus as control. The experiment was laid out in a completely randomized block design with three replicates. Data were collected on weed flora, weed density and weed dry weight. Results showed that the relative frequencies of weeds in all the plots were less than 4% at both 6 and 9WAP. Gomphrena celosoides, Oldenlandia corymbosa and Tridax procumbens were most preponderant in appearing in all the plots. Tridax procumbens had a consistent relative frequency (2.34% in all the plots except in citrus/maize plot (0.78% at 9 WAP. Significantly lower broadleaf weed densities were obtained in citrus/sweet potato, citrus/large green, control plot and citrus/cucumber (28.67, 45.00, 50.00 and 76.33 m-2 respectively than in citrus/groundnut plot (143.00 m-2. Similarly, significantly lower grass weed densities were produced in citrus/Mucuna and citrus/sweet potato (0.33 m-2 each plots than the control plot (11.33 m-2. Whereas citrus/corchorus plot produced significantly lower broadleaf weed dry weight (37.59 g m-2 than citrus/Mucuna plot (126.47 g m-2 at 3WAP, citrus/large green plot (16.15 g m-2 and citrus/groundnut plot (123.25 g m-2 followed the same trend at 6 WAP. Sedges dry weights were less than 7 g m-2 in all the plots compared with control plot.

  12. Learning to fight a fly : developing citrus IPM in Bhutan

    OpenAIRE

    Schoubroeck, van, F.H.J.

    1999-01-01

    The chinese citrus fly is one of the key pests in Bhutanese mandarin orchards that lays eggs in developing fruit that cause pre-mature fruit drop. In this study it is used as a "model subject" to explore the integration of technical, social and administrative domains of knowledge. The confinement of the study to control of the fly leads to the study addressing a broad set of issues that are linked through their relevance to control the pest. Citrus fly control and its consequent doub...

  13. Influence of Metalaxyl on Three Nematodes of Citrus

    Science.gov (United States)

    Kaplan, David T.

    1983-01-01

    Metalaxyl significantly reduced population of Pratylenchus coffeae, Radopholus similis, and Tylenchulus semipenetrans in roots of Citrus limon (rough lemon) under greenhouse conditions. Postinoculation treatment of rough lemon seedlings was not as effective i n reducing nematode populations as was treatment before inoculation. Fewer nematodes infected metalaxyl-treated roots than nontreated roots. However, incubation of nematodes in metalaxyl did not inhibit nematode motility or their ability to locate and infect roots. Cellular responses to nematode injection differed between treated and nontreated tissues. Metalaxyl appeared to confer nematode contraol by modifying citrus roots such that a normally susceptible rootstock became tolerant. PMID:19295833

  14. In vivo Induction of Tetraploid in Tangerine Citrus Plants (Citrus reticulata Blanco) with the Use of Colchicine.

    Science.gov (United States)

    Surson, Suntaree; Sitthaphanit, Suphasit; Wongma, Nattapong

    2015-01-01

    This in vivo experiment was carried out at Sakhon Nakhon Rajabhat University, Sakhon Nakhon Province, Thailand during March-October 2013. The study aims to search for some possibilities in inducing a large number of tetraploid sets of chromosomes in tangerine citrus seedlings with the use of colchicine chemical. A Randomized Complete Block Design (RCBD) with four replications was used. Seeds of tangerine citrus were treated with colchicine solutions. The experiment consisted of seven treatments, i.e., T1 with 0.0% colchicine (control), T2 with 0.2% colchicine solution and submerged for 12 h, T3 with 0.2% colchicine solution and submerged for 24 h, T4 with 0.4% colchicine solution and submerged for 12 h, T5 with 0.4% colchicine solution and submerged for 24 h, T6 with 0.8% colchicine solution and submerged for 12 h, T7 with 0.8% colchicine solution and submerged for 24 h. The experiment was conducted for 91 days. The results showed that colchicine compound severely and significantly affected germination of tangerine citrus seeds. Colchicine of 0.2% in the solution with seeds submerged for 24 h gave the highest percentages of tetraploid chromosomes in seedlings of tangerine citrus (63.64%). Colchicine significantly affected seed germination, plant height, stomata density and leaf index of the tangerine citrus seeds and seedlings. Colchicine had no significant effect on poly-embryos, mono-embryos, leaf number, leaf area, leaf weight, leaf length and stomata length of the tangerine citrus seedlings.

  15. The Draft Genome Sequence of Xanthomonas sp. Strain Mitacek01 Expands the Pangenome of a Genus of Plant Pathogens.

    Science.gov (United States)

    Couger, M B; Hanafy, Radwa A; Mitacek, Rachel M; Budd, Connie; French, Donald P; Hoff, Wouter D; Elshahed, Mostafa S; Youssef, Noha H

    2015-12-10

    We report the draft genome sequence of Xanthomonas sp. strain Mitacek01, isolated from an indoor environment vending machine surface with frequent human use in Stillwater, Oklahoma, USA, as part of the Student-Initiated Microbial Discovery project. The genome has a total size of 3,617,426 bp and a contig N50 of 1,906,967 bp.

  16. Produção e caracterização de anticorpos policlonais contra Xanthomonas campestris pv. viticola.

    OpenAIRE

    2005-01-01

    O objetivo deste trabalho foi a produção de anticorpos policlonais contra Xanthomonas campestris pv. viticola e sua caracterização pelo método Elisa indireto. Os resultados apontaram a qualidade dos anticorpos policlonais produzidos, os quais mostraram-se altamente reativos e específicos para o patovar com potencial para ser empregado no diagnóstico da doença e em programas de certificação.

  17. Novel Rosaceae Plant Elicitor Peptides as sustainable tools to control Xanthomonas arboricola pv. pruni in Prunus spp

    OpenAIRE

    Ruiz Beltrán, Cristina; Nadal i Matamala, Anna; Montesinos Seguí, Emilio; Pla i de Solà-Morales, Maria

    2017-01-01

    Fruit crops are regarded as important health promoters and constitute a major part of global agricultural production, and Rosaceae species are of high economic impact. Their culture is threatened by bacterial diseases, which control is only based on preventive treatment with compounds with limited efficacy and a negative environmental impact. One of the most economically relevant examples is the pathogen Xanthomonas arboricola pv. pruni (Xap) affecting Prunus spp. Plant immune response agains...

  18. Inoculação e sobrevivência de Xanthomonas vesicatoria em sementes de tomateiro Inoculation and survival of Xanthomonas vesicatoria on tomato seeds

    Directory of Open Access Journals (Sweden)

    Fábio Mathias Corrêa

    2008-02-01

    Full Text Available Para avaliar o efeito de métodos de inocuação de Xanthomonas vesicatoria (Doidge (9 em sementes de tomate sobre a qualidade da semente e transmissão da fitobactéria compararam-se os tratamentos: 1 inoculação a vácuo com suspensão de células de X. vesicatoria em STP (0,005M, pH 7,4 e NaCl 0,85%; 2 imersão por 24 horas em suspensão de células de X. vesicatoria em STP; 3 vácuo em solução STP; 4 imersão por 24 horas em STP; 5 imersão por 5 min. em álcool etílico e 6 semente original. As avaliações foram realizadas por testes de germinação e isolamentos em meio Nutriente Agar Modificado (NAM aos 1, 15, 30 e 45 dias após aplicação dos tratamentos. Em seguida, avaliou-se o efeito da umidade (4% e 8% e o armazenamento das sementes inoculadas e variações de umidade antes da realização dos testes sobre a sobrevivência e recuperação de X. vesicatoria. Os métodos de inoculação testados podem ser utilizados em trabalhos de rotina, porém, as sementes devem ser utilizadas até 30 dias após a inoculação a partir de quando ocorre uma redução acentuada na taxa de recuperação da fitobactéria. A umidade das sementes interfere na sobrevivência e na transmissão de X. vesicatoria pelas sementes de tomate.The efficiency of six methods of Xanthomonas vesicatoria (Doidge (9 inoculation on tomato seeds, and their effects on seed quality were tested : 1 vacuum inoculation with X. vesicatoria cell suspension in PB (0.005M, pH 7.4 e NaCl 0.85%; 2 immersion for 24 hours in with X. vesicatoria cell suspension and PB. 3 vacuum and saline solution in phosphate buffer; 4 immersion in PB for 24 hours; 5 seeds + ethanol; 6 control. Evaluations were performed for germination test and isolation in Modified Agar Nutrient (NAM at 1, 15, 30 and 45 days after treatments imposition. The moisture effect on the transmission of X. vesicatoria seeds inoculated under vacuum, followed or not by air drying at 30±1 ºC, until 4% and 8% moisture

  19. Effect of aqueous extract from turmeric (Curcuma longa on Xanthomonas axonopodis pv. manihotis/ Efeito do extrato aquoso de cúrcuma (Curcuma longa em Xanthomonas axonopodis pv. manihotis

    Directory of Open Access Journals (Sweden)

    Gilmar Franzener

    2006-06-01

    Full Text Available The control of Xanthomonas axonopodis pv. manihotis was evaluated in vitro by using aqueous extract of four turmeric genotypes from Jaboticabal-SP, Mara Rosa-GO, Maringá-PR and Mercedes-PR, as well as in vivo, by treatment of infected cassava stems and their cultivation at field conditions. The results showed that in vitro experiment, turmeric extract inhibited completely the bacteria growth in the concentration of 10% for the genotype from Mercedes, while for the Jaboticabal’s turmeric there was a total control at 15% and for Mara Rosa at 20%. Turmeric genotype from Maringá did not show full inhibition of the bacterial growth in none of the extract concentrations used. At field conditions, sproutings were extremely low, due to the stems infection degree. Turmeric extract at 10%, from Mercedes, was harmful for the cassava, reducing stand regarding the control treatments. Possibly there was a direct toxic action on the plant physiology or susceptibility induction. But in the concentration of 1% of turmeric from Maringá, there was no statistical difference in relation to the control treatment for the plant stand. The chemical control was not completely efficient. There was no statistical difference among treatments for both severity and productivity. The results indicate that, although presenting antibacterial activity to X. axonopodis pv. manihotis, the turmeric extracts, in the used concentrations, did not present curative effect in cassava stems infected with the pathogen.Avaliou-se o controle in vitro de Xanthomonas axonopodis pv. manihotis mediante o uso de extrato aquoso de quatro genótipos de cúrcuma provenientes de cultivos de Jaboticabal-SP, Mara Rosa-GO, Maringá-PR e Mercedes-PR, bem como o efeito curativo, através do tratamento de manivas de mandioca infectadas com o patógeno e plantio em condições de campo. No experimento in vitro, o extrato de cúrcuma causou inibição total do crescimento da bactéria, na concentra

  20. A Redox 2-Cys Mechanism Regulates the Catalytic Activity of Divergent Cyclophilins1[W

    Science.gov (United States)

    Campos, Bruna Medéia; Sforça, Mauricio Luis; Ambrosio, Andre Luis Berteli; Domingues, Mariane Noronha; Brasil de Souza, Tatiana de Arruda Campos; Barbosa, João Alexandre Ribeiro Gonçalvez; Leme, Adriana Franco Paes; Perez, Carlos Alberto; Whittaker, Sara Britt-Marie; Murakami, Mario Tyago; Zeri, Ana Carolina de Matos; Benedetti, Celso Eduardo

    2013-01-01

    The citrus (Citrus sinensis) cyclophilin CsCyp is a target of the Xanthomonas citri transcription activator-like effector PthA, required to elicit cankers on citrus. CsCyp binds the citrus thioredoxin CsTdx and the carboxyl-terminal domain of RNA polymerase II and is a divergent cyclophilin that carries the additional loop KSGKPLH, invariable cysteine (Cys) residues Cys-40 and Cys-168, and the conserved glutamate (Glu) Glu-83. Despite the suggested roles in ATP and metal binding, the functions of these unique structural elements remain unknown. Here, we show that the conserved Cys residues form a disulfide bond that inactivates the enzyme, whereas Glu-83, which belongs to the catalytic loop and is also critical for enzyme activity, is anchored to the divergent loop to maintain the active site open. In addition, we demonstrate that Cys-40 and Cys-168 are required for the interaction with CsTdx and that CsCyp binds the citrus carboxyl-terminal domain of RNA polymerase II YSPSAP repeat. Our data support a model where formation of the Cys-40-Cys-168 disulfide bond induces a conformational change that disrupts the interaction of the divergent and catalytic loops, via Glu-83, causing the active site to close. This suggests a new type of allosteric regulation in divergent cyclophilins, involving disulfide bond formation and a loop-displacement mechanism. PMID:23709667