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Sample records for citrus pathogen alternaria

  1. The glutathione peroxidase-mediated reactive oxygen species resistance, fungicide sensitivity and cell wall construction in the citrus fungal pathogen Alternaria alternata.

    PubMed

    Yang, Siwy Ling; Yu, Pei-Ling; Chung, Kuang-Ren

    2016-03-01

    The ability to detoxify reactive oxygen species (ROS) is critical for pathogenicity in the necrotrophic fungus Alternaria alternata. We report a glutathione peroxidase 3 (AaGPx3) involved in the complex signalling network that is essential for the detoxification of cellular stresses induced by ROS and for A. alternata pathogenesis in citrus. AaGPx3 deletion mutants displayed increased sensitivity to H2 O2 and many ROS-generating compounds. AaGPx3 is required for correct fungal development as the AaGPx3 mutant strains showed a severe reduction in conidiation. AaGPx3 mutants accumulated higher chitin content than the wild-type and were less sensitive to the cell wall-targeting compounds calcofluor white and Congo red, as well as the fungicides fludioxonil and vinclozolin, suggesting a role of the glutathione systems in fungal cell wall construction. Virulence assays revealed that AaGPx3 is required for full virulence. The expression of AaGPx3 was downregulated in fungal strains carrying defective NADPH oxidase (Nox) or the oxidative stress responsive regulators YAP1 and HOG1, all implicated in ROS resistance. These results further support the important role of ROS detoxification during A. alternata pathogenesis in citrus. Overall, our study provides genetic evidence to define the central role of AaGPx3 in the biological and pathological functions of A. alternata. PMID:26567914

  2. Large-spored Alternaria pathogens in section Porri disentangled

    PubMed Central

    Woudenberg, J.H.C.; Truter, M.; Groenewald, J.Z.; Crous, P.W.

    2014-01-01

    The omnipresent fungal genus Alternaria was recently divided into 24 sections based on molecular and morphological data. Alternaria sect. Porri is the largest section, containing almost all Alternaria species with medium to large conidia and long beaks, some of which are important plant pathogens (e.g. Alternaria porri, A. solani and A. tomatophila). We constructed a multi-gene phylogeny on parts of the ITS, GAPDH, RPB2, TEF1 and Alt a 1 gene regions, which, supplemented with morphological and cultural studies, forms the basis for species recognition in sect. Porri. Our data reveal 63 species, of which 10 are newly described in sect. Porri, and 27 species names are synonymised. The three known Alternaria pathogens causing early blight on tomato all cluster in one clade, and are synonymised under the older name, A. linariae. Alternaria protenta, a species formerly only known as pathogen on Helianthus annuus, is also reported to cause early blight of potato, together with A. solani and A. grandis. Two clades with isolates causing purple blotch of onion are confirmed as A. allii and A. porri, but the two species cannot adequately be distinguished based on the number of beaks and branches as suggested previously. This is also found among the pathogens of Passifloraceae, which are reduced from four to three species. In addition to the known pathogen of sweet potato, A. bataticola, three more species are delineated of which two are newly described. A new Alternaria section is also described, comprising two large-spored Alternaria species with concatenate conidia. PMID:25492985

  3. Large-spored Alternaria pathogens in section Porri disentangled.

    PubMed

    Woudenberg, J H C; Truter, M; Groenewald, J Z; Crous, P W

    2014-09-01

    The omnipresent fungal genus Alternaria was recently divided into 24 sections based on molecular and morphological data. Alternaria sect. Porri is the largest section, containing almost all Alternaria species with medium to large conidia and long beaks, some of which are important plant pathogens (e.g. Alternaria porri, A. solani and A. tomatophila). We constructed a multi-gene phylogeny on parts of the ITS, GAPDH, RPB2, TEF1 and Alt a 1 gene regions, which, supplemented with morphological and cultural studies, forms the basis for species recognition in sect. Porri. Our data reveal 63 species, of which 10 are newly described in sect. Porri, and 27 species names are synonymised. The three known Alternaria pathogens causing early blight on tomato all cluster in one clade, and are synonymised under the older name, A. linariae. Alternaria protenta, a species formerly only known as pathogen on Helianthus annuus, is also reported to cause early blight of potato, together with A. solani and A. grandis. Two clades with isolates causing purple blotch of onion are confirmed as A. allii and A. porri, but the two species cannot adequately be distinguished based on the number of beaks and branches as suggested previously. This is also found among the pathogens of Passifloraceae, which are reduced from four to three species. In addition to the known pathogen of sweet potato, A. bataticola, three more species are delineated of which two are newly described. A new Alternaria section is also described, comprising two large-spored Alternaria species with concatenate conidia. PMID:25492985

  4. Comparative Genomics of Pathogens Causing Brown Spot Disease of Tobacco: Alternaria longipes and Alternaria alternata

    PubMed Central

    Wan, Wenting; Long, Ni; Zhang, Jing; Tan, Yuntao; Duan, Shengchang; Zeng, Yan; Dong, Yang

    2016-01-01

    The genus Alternaria is a group of infectious/contagious pathogenic fungi that not only invade a wide range of crops but also induce severe allergic reactions in a part of the human population. In this study, two strains Alternaria longipes cx1 and Alternaria alternata cx2 were isolated from different brown spot lesions on infected tobacco leaves. Their complete genomes were sequenced, de novo assembled, and comparatively analyzed. Phylogenetic analysis revealed that A. longipes cx1 and A. alternata cx2 diverged 3.3 million years ago, indicating a recent event of speciation. Seventeen non-ribosomal peptide synthetase (NRPS) genes and 13 polyketide synthase (PKS) genes in A. longipes cx1 and 13 NRPS genes and 12 PKS genes in A. alternata cx2 were identified in these two strains. Some of these genes were predicted to participate in the synthesis of non-host specific toxins (non-HSTs), such as tenuazonic acid (TeA), alternariol (AOH) and alternariol monomethyl ether (AME). By comparative genome analysis, we uncovered that A. longipes cx1 had more genes putatively involved in pathogen-plant interaction, more carbohydrate-degrading enzymes and more secreted proteins than A. alternata cx2. In summary, our results demonstrate the genomic distinction between A. longipes cx1 and A. altenata cx2. They will not only improve the understanding of the phylogenetic relationship among genus Alternaria, but more importantly provide valuable genomic resources for the investigation of plant-pathogen interaction. PMID:27159564

  5. Comparative Genomics of Pathogens Causing Brown Spot Disease of Tobacco: Alternaria longipes and Alternaria alternata.

    PubMed

    Hou, Yujie; Ma, Xiao; Wan, Wenting; Long, Ni; Zhang, Jing; Tan, Yuntao; Duan, Shengchang; Zeng, Yan; Dong, Yang

    2016-01-01

    The genus Alternaria is a group of infectious/contagious pathogenic fungi that not only invade a wide range of crops but also induce severe allergic reactions in a part of the human population. In this study, two strains Alternaria longipes cx1 and Alternaria alternata cx2 were isolated from different brown spot lesions on infected tobacco leaves. Their complete genomes were sequenced, de novo assembled, and comparatively analyzed. Phylogenetic analysis revealed that A. longipes cx1 and A. alternata cx2 diverged 3.3 million years ago, indicating a recent event of speciation. Seventeen non-ribosomal peptide synthetase (NRPS) genes and 13 polyketide synthase (PKS) genes in A. longipes cx1 and 13 NRPS genes and 12 PKS genes in A. alternata cx2 were identified in these two strains. Some of these genes were predicted to participate in the synthesis of non-host specific toxins (non-HSTs), such as tenuazonic acid (TeA), alternariol (AOH) and alternariol monomethyl ether (AME). By comparative genome analysis, we uncovered that A. longipes cx1 had more genes putatively involved in pathogen-plant interaction, more carbohydrate-degrading enzymes and more secreted proteins than A. alternata cx2. In summary, our results demonstrate the genomic distinction between A. longipes cx1 and A. altenata cx2. They will not only improve the understanding of the phylogenetic relationship among genus Alternaria, but more importantly provide valuable genomic resources for the investigation of plant-pathogen interaction. PMID:27159564

  6. Asian citrus psyllid viral pathogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A newly discovered viral pathogen of Asian citrus psyllid, AsCP, Diaphorina citri, Kuwayama (Psyllidae: Hemiptera) was classified as a Reoviridae. This virus may serve as a biological control agent for AsCP. The AsCP is an efficient vector of the plant-infecting bacterium (Candidatus Liberibacter as...

  7. Comparison of methodologies for conidia production by Alternaria alternata from citrus

    PubMed Central

    Carvalho, Daniel D. C.; Alves, Eduardo; Batista, Tereza R. S.; Camargos, Renato B.; Lopes, Eloísa A. G. L.

    2008-01-01

    Conidia production is a problem in the study of Alternaria alternata from citrus. Thus, this study aimed to compare existing methodologies for conidial production of A. alternata isolated from Ponkan tangerine (2 isolates), Cravo lemon (1 isolate), Pêra orange (2 isolates) and Murcott tangor (1 isolate). The methodologies used were conidia production with 12 and 24 hours under white fluorescent light, evaluation with 24 and 48 hours after applying fungal mycelium stress technique, cold stress followed by injury of mycelium and evaluation with 24 hours, using healthy vegetable tissue and the use of black fluorescent near ultraviolet (NUV) lamp. Satisfactory result was obtained with A. alternata isolate from Murcott tangor, with the production of 2.8 × 105 conidia mL-1, when fungal mycelium was stressed (Petri dish with 66.66% of fungi growth) and subsequently 24 h of growth. The use of white light (24 h) and black fluorescent NUV lamp also induced expressive conidia production by one isolate of Ponkan tangerine, which produced 17.2 × 105 and 10.1 × 105conidia mL-1 and another of Murcott tangor, which produced 13.9 × 105 and 10.1 × 105 conidia mL-1, respectively. The remaining methodologies analyzed in this study were not able to induce conidia production in satisfactory quantity. The use of both mycelium stress technique and white light (24 h) and black fluorescent NUV lamp allowed the production of enough quantities of conidia to be used in vitro (detection of fungitoxic substances) and in vivo (pathogenicity test) assays, respectively. PMID:24031309

  8. Digital PCR for detection of citrus pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  9. Natural occurrence of four Alternaria mycotoxins in tomato- and citrus-based foods in China.

    PubMed

    Zhao, Kai; Shao, Bing; Yang, Dajin; Li, Fengqin

    2015-01-14

    A total of 70 tomato-based and 86 citrus-based products collected in China were analyzed for alternariol, alternariol monomethyl ether, tentoxin, and tenuazonic acid by ultraperformance liquid chromatography–electrospray ionization–tandem mass spectrometry. No toxins were found in any fresh tomato or citrus fruit samples. Tenuazonic acid was the predominant toxin detected in all tomato ketchup (10.2–1787 μg/kg) and tomato juice samples (7.4–278 μg/kg). Alternariol was quantitated at higher level than alternariol monomethyl ether with the ratio of alternariol/alternariol monomethyl ether ranging from 0.37 to 104 in 14 alternariol-positive tomato ketchup samples. Tentoxin was detected at much lower levels in all samples analyzed. Some citrus juice samples were positive for tenuazonic acid and alternariol monomethyl ether. It is necessary to conduct a systemic surveillance of Alternaria toxins in raw and processed foods to provide the scientific basis for risk assessment of dietary exposure to these toxins in Chinese populations. PMID:25520156

  10. Alternaria redefined

    PubMed Central

    Woudenberg, J.H.C.; Groenewald, J.Z.; Binder, M.; Crous, P.W.

    2013-01-01

    Alternaria is a ubiquitous fungal genus that includes saprobic, endophytic and pathogenic species associated with a wide variety of substrates. In recent years, DNA-based studies revealed multiple non-monophyletic genera within the Alternaria complex, and Alternaria species clades that do not always correlate to species-groups based on morphological characteristics. The Alternaria complex currently comprises nine genera and eight Alternaria sections. The aim of this study was to delineate phylogenetic lineages within Alternaria and allied genera based on nucleotide sequence data of parts of the 18S nrDNA, 28S nrDNA, ITS, GAPDH, RPB2 and TEF1-alpha gene regions. Our data reveal a Pleospora/Stemphylium clade sister to Embellisia annulata, and a well-supported Alternaria clade. The Alternaria clade contains 24 internal clades and six monotypic lineages, the assemblage of which we recognise as Alternaria. This puts the genera Allewia, Brachycladium, Chalastospora, Chmelia, Crivellia, Embellisia, Lewia, Nimbya, Sinomyces, Teretispora, Ulocladium, Undifilum and Ybotromyces in synonymy with Alternaria. In this study, we treat the 24 internal clades in the Alternaria complex as sections, which is a continuation of a recent proposal for the taxonomic treatment of lineages in Alternaria. Embellisia annulata is synonymised with Dendryphiella salina, and together with Dendryphiella arenariae, are placed in the new genus Paradendryphiella. The sexual genera Clathrospora and Comoclathris, which were previously associated with Alternaria, cluster within the Pleosporaceae, outside Alternaria s. str., whereas Alternariaster, a genus formerly seen as part of Alternaria, clusters within the Leptosphaeriaceae. Paradendryphiella is newly described, the generic circumscription of Alternaria is emended, and 32 new combinations and 10 new names are proposed. A further 10 names are resurrected, while descriptions are provided for 16 new Alternaria sections. Taxonomic novelties: New

  11. Phylogenetic, Morphological, and Pathogenic Characterization of Alternaria Species Associated with Fruit Rot of Blueberry in California.

    PubMed

    Zhu, X Q; Xiao, C L

    2015-12-01

    Fruit rot caused by Alternaria spp. is one of the most important factors affecting the postharvest quality and shelf life of blueberry fruit. The aims of this study were to characterize Alternaria isolates using morphological and molecular approaches and test their pathogenicity to blueberry fruit. Alternaria spp. isolates were collected from decayed blueberry fruit in the Central Valley of California during 2012 and 2013. In total, 283 isolates were obtained and five species of Alternaria, including Alternaria alternata, A. tenuissima, A. arborescens, A. infectoria, and A. rosae, were identified based on DNA sequences of the plasma membrane ATPase, Alt a1 and Calmodulin gene regions in combination with morphological characters of the culture and sporulation. Of the 283 isolates, 61.5% were identified as A. alternata, 32.9% were A. arborescens, 5.0% were A. tenuissima, and only one isolate of A. infectoria and one isolate of A. rosae were found. These fungi were able to grow at temperatures from 0 to 35°C, and mycelial growth was arrested at 40°C. Optimal radial growth occurred between 20 to 30°C. Pathogenicity tests showed that all five Alternaria spp. were pathogenic on blueberry fruit at 0, 4, and 20°C, with A. alternata, A. arborescens, and A. tenuissima being the most virulent species, followed by A. infectoria and A. rosae. Previously A. tenuissima has been reported to be the primary cause of Alternaria fruit rot of blueberry worldwide. Our results indicated that the species composition of Alternaria responsible for Alternaria fruit rot in blueberry can be dependent on geographical region. A. alternata, A. arborescens, A. infectoria, and A. rosae are reported for the first time on blueberry in California. This is also the first report of A. infectoria and A. rosae infecting blueberry fruit. PMID:26267542

  12. New Pseudomonas spp. Are Pathogenic to Citrus

    PubMed Central

    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. PMID:26919540

  13. New Pseudomonas spp. Are Pathogenic to Citrus.

    PubMed

    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. PMID:26919540

  14. Alternaria blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternaria blight of chickpea is caused by the fungal pathogen Alternaria alternata. The pathogen has wide host range, and affects all above ground parts of the plant. The disease occurs sporadically and occasionally could be economically important and causes significant damage. The pathogen can ...

  15. Proteome Analysis of Pathogen-Responsive Proteins from Apple Leaves Induced by the Alternaria Blotch Alternaria alternata

    PubMed Central

    Zhang, Cai-xia; Tian, Yi; Cong, Pei-hua

    2015-01-01

    Understanding the defence mechanisms used by apple leaves against Alternaria alternate pathogen infection is important for breeding purposes. To investigate the ultrastructural differences between leaf tissues of susceptible and resistant seedlings, in vitro inoculation assays and transmission electron microscopy (TEM) analysis were conducted with two different inoculation assays. The results indicated that the resistant leaves may have certain antifungal activity against A. alternate that is lacking in susceptible leaves. To elucidate the two different host responses to A. alternate infection in apples, the proteomes of susceptible and resistant apple leaves that had or had not been infected with pathogen were characterised using two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionisation time-of-flight tandem mass spectrometry (MALDI-TOF-TOF MS). MS identified 43 differentially expressed proteins in two different inoculation assays. The known proteins were categorised into 5 classes, among these proteins, some pathogenesis-related (PR) proteins, such as beta-1,3-glucanase, ascorbate peroxidase (APX), glutathione peroxidase (GPX) and mal d1, were identified in susceptible and resistant hosts and were associated with disease resistance of the apple host. In addition, the different levels of mal d1 in susceptible and resistant hosts may contribute to the outstanding anti-disease properties of resistant leaves against A. alternate. Taken together, the resistance mechanisms of the apple host against A. alternate may be a result of the PR proteins and other defence-related proteins. Given the complexity of the biology involved in the interaction between apple leaves and the A. alternate pathogen, further investigation will yield more valuable insights into the molecular mechanisms of suppression of the A. alternate pathogen. Overall, we outline several novel insights into the response of apple leaves to pathogen attacks. These findings

  16. How the Pathogenic Fungus Alternaria alternata Copes with Stress via the Response Regulators SSK1 and SHO1.

    PubMed

    Yu, Pei-Ling; Chen, Li-Hung; Chung, Kuang-Ren

    2016-01-01

    The tangerine pathotype of Alternaria alternata is a necrotrophic fungal pathogen causing brown spot disease on a number of citrus cultivars. To better understand the dynamics of signal regulation leading to oxidative and osmotic stress response and fungal infection on citrus, phenotypic characterization of the yeast SSK1 response regulator homolog was performed. It was determined that SSK1 responds to diverse environmental stimuli and plays a critical role in fungal pathogenesis. Experiments to determine the phenotypes resulting from the loss of SSK1 reveal that the SSK1 gene product may be fulfilling similar regulatory roles in signaling pathways involving a HOG1 MAP kinase during ROS resistance, osmotic resistance, fungicide sensitivity and fungal virulence. The SSK1 mutants display elevated sensitivity to oxidants, fail to detoxify H2O2 effectively, induce minor necrosis on susceptible citrus leaves, and displays resistance to dicarboximide and phenylpyrrole fungicides. Unlike the SKN7 response regulator, SSK1 and HOG1 confer resistance to salt-induced osmotic stress via an unknown kinase sensor rather than the "two component" histidine kinase HSK1. SSK1 and HOG1 play a moderate role in sugar-induced osmotic stress. We also show that SSK1 mutants are impaired in their ability to produce germ tubes from conidia, indicating a role for the gene product in cell differentiation. SSK1 also is involved in multi-drug resistance. However, deletion of the yeast SHO1 (synthetic high osmolarity) homolog resulted in no noticeable phenotypes. Nonetheless, our results show that A. alternata can sense and react to different types of stress via SSK1, HOG1 and SKN7 in a cooperative manner leading to proper physiological and pathological functions. PMID:26863027

  17. How the Pathogenic Fungus Alternaria alternata Copes with Stress via the Response Regulators SSK1 and SHO1

    PubMed Central

    Yu, Pei-Ling; Chen, Li-Hung; Chung, Kuang-Ren

    2016-01-01

    The tangerine pathotype of Alternaria alternata is a necrotrophic fungal pathogen causing brown spot disease on a number of citrus cultivars. To better understand the dynamics of signal regulation leading to oxidative and osmotic stress response and fungal infection on citrus, phenotypic characterization of the yeast SSK1 response regulator homolog was performed. It was determined that SSK1 responds to diverse environmental stimuli and plays a critical role in fungal pathogenesis. Experiments to determine the phenotypes resulting from the loss of SSK1 reveal that the SSK1 gene product may be fulfilling similar regulatory roles in signaling pathways involving a HOG1 MAP kinase during ROS resistance, osmotic resistance, fungicide sensitivity and fungal virulence. The SSK1 mutants display elevated sensitivity to oxidants, fail to detoxify H2O2 effectively, induce minor necrosis on susceptible citrus leaves, and displays resistance to dicarboximide and phenylpyrrole fungicides. Unlike the SKN7 response regulator, SSK1 and HOG1 confer resistance to salt-induced osmotic stress via an unknown kinase sensor rather than the “two component” histidine kinase HSK1. SSK1 and HOG1 play a moderate role in sugar-induced osmotic stress. We also show that SSK1 mutants are impaired in their ability to produce germ tubes from conidia, indicating a role for the gene product in cell differentiation. SSK1 also is involved in multi-drug resistance. However, deletion of the yeast SHO1 (synthetic high osmolarity) homolog resulted in no noticeable phenotypes. Nonetheless, our results show that A. alternata can sense and react to different types of stress via SSK1, HOG1 and SKN7 in a cooperative manner leading to proper physiological and pathological functions. PMID:26863027

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  19. Comparison of pathogenicity of Alternaria pellucida and Curvularia lunata on weed Echinochloa species.

    PubMed

    Reza, Mohammad; Motlagh, Safari

    2015-07-01

    Echinochloa spp. are the most important weeds in rice fields. In this research Curvularia lunata and Alternaria pellucida were isolated from these weeds and their pathogenicity effects were compared on these weeds and five rice cultivars in a completely random design with three replications in greenhouse conditions. Fungi were inoculated on weeds and rice cultivars, using spore suspension consisting of 10' spore ml(-1) of distilled water. Results indicated significant effect of Curvularia lunata and Alternaria pellucida on Echinochloa oryzicola and E. crus-galli. In the present study, effect of C. lunata on fresh weight, dry weight and height of Echinochloa species based on variance analysis table, a significant reaction was observed for height and fresh weight, but for dry weight reaction was not significant. The effect of A. pellucida on fresh weight, dry weight and height of Echinochloa species based on variance analysis table, a significant reaction was observed for all the three traits. Also, rice cultivars did not show any significant reaction to C. lunata and A. pellucida. The results showed that in comparison between effect of Curvularia lunata and Alternaria pellucida on Echinochloa spp., disease rating caused by A. pellucida on E. oryzicola and E. crusalli was more than disease rating caused by C. lunata and these species of weed were more susceptible to A. pellucida. However, A. alternata can be considered as a better promising bioherbicide to control Echinochloa spp. PMID:26364476

  20. Genetically Based Location from Triploid Populations and Gene Ontology of a 3.3-Mb Genome Region Linked to Alternaria Brown Spot Resistance in Citrus Reveal Clusters of Resistance Genes

    PubMed Central

    Cuenca, José; Aleza, Pablo; Vicent, Antonio; Brunel, Dominique; Ollitrault, Patrick; Navarro, Luis

    2013-01-01

    Genetic analysis of phenotypical traits and marker-trait association in polyploid species is generally considered as a challenge. In the present work, different approaches were combined taking advantage of the particular genetic structures of 2n gametes resulting from second division restitution (SDR) to map a genome region linked to Alternaria brown spot (ABS) resistance in triploid citrus progeny. ABS in citrus is a serious disease caused by the tangerine pathotype of the fungus Alternaria alternata. This pathogen produces ACT-toxin, which induces necrotic lesions on fruit and young leaves, defoliation and fruit drop in susceptible genotypes. It is a strong concern for triploid breeding programs aiming to produce seedless mandarin cultivars. The monolocus dominant inheritance of susceptibility, proposed on the basis of diploid population studies, was corroborated in triploid progeny. Bulk segregant analysis coupled with genome scan using a large set of genetically mapped SNP markers and targeted genetic mapping by half tetrad analysis, using SSR and SNP markers, allowed locating a 3.3 Mb genomic region linked to ABS resistance near the centromere of chromosome III. Clusters of resistance genes were identified by gene ontology analysis of this genomic region. Some of these genes are good candidates to control the dominant susceptibility to the ACT-toxin. SSR and SNP markers were developed for efficient early marker-assisted selection of ABS resistant hybrids. PMID:24116149

  1. Pathogen infection drives patterns of nutrient resorption in citrus plants.

    PubMed

    Cao, Jirong; Cheng, Chunzhen; Yang, Junjie; Wang, Qibing

    2015-01-01

    Nutrient resorption processes in the plants infected by pathogen remain poorly understood. Huanglongbing (HLB) is a destructive disease of citrus. HLB-pathogen 'Candidatus Liberibacter asiaticus' grows specifically in the phloem of hosts and may cause problems in the plant vascular system after infection. Therefore, it brings a great concern about the phloem nutrient transport and nutrient intra-cycling in HLB-affected plants. We investigated the effects of 'Ca. L. asiaticus' infection on nitrogen (N) and phosphorus (P) concentrations and resorption in different citrus species (i.e. Citrus reticulata, Citrus limon and Citrus maxima). HLB-pathogen infection had distinctive impacts on nutrient resorption in different species. P resorption efficiency substantially decreased in infected C. reticulata plants relative to the healthy plants in summer, which may account for the marked decrease in the average fruit yield. P resorption was more efficient in infected C. limon plants than in the healthy plants. However, for C. maxima plants, HLB had no significant effects on N:P ratio in live leaves and resorption efficiency as well as on fruit yield. Keeping efficient internal nutrient cycling can be a strategy of citrus species being tolerant to HLB. PMID:26419510

  2. Pathogen infection drives patterns of nutrient resorption in citrus plants

    PubMed Central

    Cao, Jirong; Cheng, Chunzhen; Yang, Junjie; Wang, Qibing

    2015-01-01

    Nutrient resorption processes in the plants infected by pathogen remain poorly understood. Huanglongbing (HLB) is a destructive disease of citrus. HLB-pathogen ‘Candidatus Liberibacter asiaticus’ grows specifically in the phloem of hosts and may cause problems in the plant vascular system after infection. Therefore, it brings a great concern about the phloem nutrient transport and nutrient intra-cycling in HLB-affected plants. We investigated the effects of ‘Ca. L. asiaticus’ infection on nitrogen (N) and phosphorus (P) concentrations and resorption in different citrus species (i.e. Citrus reticulata, Citrus limon and Citrus maxima). HLB-pathogen infection had distinctive impacts on nutrient resorption in different species. P resorption efficiency substantially decreased in infected C. reticulata plants relative to the healthy plants in summer, which may account for the marked decrease in the average fruit yield. P resorption was more efficient in infected C. limon plants than in the healthy plants. However, for C. maxima plants, HLB had no significant effects on N:P ratio in live leaves and resorption efficiency as well as on fruit yield. Keeping efficient internal nutrient cycling can be a strategy of citrus species being tolerant to HLB. PMID:26419510

  3. Role of mannitol metabolism in the pathogenicity of the necrotrophic fungus Alternaria brassicicola

    PubMed Central

    Calmes, Benoit; Guillemette, Thomas; Teyssier, Lény; Siegler, Benjamin; Pigné, Sandrine; Landreau, Anne; Iacomi, Béatrice; Lemoine, Rémi; Richomme, Pascal; Simoneau, Philippe

    2013-01-01

    In this study, the physiological functions of fungal mannitol metabolism in the pathogenicity and protection against environmental stresses were investigated in the necrotrophic fungus Alternaria brassicicola. Mannitol metabolism was examined during infection of Brassica oleracea leaves by sequential HPLC quantification of the major soluble carbohydrates and expression analysis of genes encoding two proteins of mannitol metabolism, i.e., a mannitol dehydrogenase (AbMdh), and a mannitol-1-phosphate dehydrogenase (AbMpd). Knockout mutants deficient for AbMdh or AbMpd and a double mutant lacking both enzyme activities were constructed. Their capacity to cope with various oxidative and drought stresses and their pathogenic behavior were evaluated. Metabolic and gene expression profiling indicated an increase in mannitol production during plant infection. Depending on the mutants, distinct pathogenic processes, such as leaf and silique colonization, sporulation, survival on seeds, were impaired by comparison to the wild-type. This pathogenic alteration could be partly explained by the differential susceptibilities of mutants to oxidative and drought stresses. These results highlight the importance of mannitol metabolism with respect to the ability of A. brassicicola to efficiently accomplish key steps of its pathogenic life cycle. PMID:23717316

  4. Role of mannitol metabolism in the pathogenicity of the necrotrophic fungus Alternaria brassicicola.

    PubMed

    Calmes, Benoit; Guillemette, Thomas; Teyssier, Lény; Siegler, Benjamin; Pigné, Sandrine; Landreau, Anne; Iacomi, Béatrice; Lemoine, Rémi; Richomme, Pascal; Simoneau, Philippe

    2013-01-01

    In this study, the physiological functions of fungal mannitol metabolism in the pathogenicity and protection against environmental stresses were investigated in the necrotrophic fungus Alternaria brassicicola. Mannitol metabolism was examined during infection of Brassica oleracea leaves by sequential HPLC quantification of the major soluble carbohydrates and expression analysis of genes encoding two proteins of mannitol metabolism, i.e., a mannitol dehydrogenase (AbMdh), and a mannitol-1-phosphate dehydrogenase (AbMpd). Knockout mutants deficient for AbMdh or AbMpd and a double mutant lacking both enzyme activities were constructed. Their capacity to cope with various oxidative and drought stresses and their pathogenic behavior were evaluated. Metabolic and gene expression profiling indicated an increase in mannitol production during plant infection. Depending on the mutants, distinct pathogenic processes, such as leaf and silique colonization, sporulation, survival on seeds, were impaired by comparison to the wild-type. This pathogenic alteration could be partly explained by the differential susceptibilities of mutants to oxidative and drought stresses. These results highlight the importance of mannitol metabolism with respect to the ability of A. brassicicola to efficiently accomplish key steps of its pathogenic life cycle. PMID:23717316

  5. Phytotoxin solanapyrone A produced by Ascochyta rabiei and Alternaria solani is nonessential for pathogenicity, but likely plays ecological roles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ascochyta rabiei and Alternaria solani, causal agents of chickpea and potato blights respectively, produce the same phytotoxin solanapyrone A (SolA).The toxicity of SolA to plants has been documented, but its role in pathogenicity has not been investigated. In this study, we generated solanapyrone-d...

  6. Enhancement of the citrus immune system provides effective resistance against Alternaria brown spot disease.

    PubMed

    Llorens, Eugenio; Fernández-Crespo, Emma; Vicedo, Begonya; Lapeña, Leonor; García-Agustín, Pilar

    2013-01-15

    In addition to basal defense mechanisms, plants are able to develop enhanced defense mechanisms such as induced resistance (IR) upon appropriate stimulation. We recently described the means by which several carboxylic acids protect Arabidopsis and tomato plants against fungi. In this work, we demonstrate the effectiveness of hexanoic acid (Hx) in the control of Alternaria brown spot (ABS) disease via enhancement of the immune system of Fortune mandarin. The application of 1mM Hx in irrigation water to 2-year-old Fortune plants clearly reduced the incidence of the disease and led to smaller lesions. We observed that several of the most important mechanisms involved in induced resistance were affected by Hx application. Our results demonstrate enhanced callose deposition in infected plants treated with Hx, which suggests an Hx priming mechanism. Plants treated with the callose inhibitor 2-DDG were more susceptible to the fungus. Moreover, polygalacturonase-inhibiting protein (PGIP) gene expression was rapidly and significantly upregulated in treated plants. However, treatment with Hx decreased the levels of reactive oxygen species (ROS) in infected plants. Hormonal and gene analyses revealed that the jasmonic acid (JA) pathway was activated due to a greater accumulation of 12-oxo-phytodienoic acid (OPDA) and JA along with a rapid accumulation of JA-isoleucine (JA-Ile). Furthermore, we observed a more rapid accumulation of abscisic acid (ABA), which could act as a positive regulator of callose deposition. Thus, our results support the hypothesis that both enhanced physical barriers and the JA signaling pathway are involved in hexanoic acid-induced resistance (Hx-IR) to Alternaria alternata. PMID:23260526

  7. Nuclear Ribosomal DNA Variation and Pathogenic Specialization in Alternaria Fungi Known To Produce Host-Specific Toxins †

    PubMed Central

    Kusaba, Motoaki; Tsuge, Takashi

    1994-01-01

    A total of 99 strains of 11 Alternaria species, including 68 strains of seven fungi known to produce host-specific toxins, were subjected to analysis of restriction fragment length polymorphism (RFLP) in nuclear ribosomal DNA (rDNA). Total DNA was digested with XbaI, and the Southern blots were probed with a nuclear rDNA clone of Alternaria kikuchiana. The hybridization gave 17 different RFLPs from the 99 strains. On the basis of these RFLPs, populations of host-specific toxin-producing fungi could not be differentiated from one another nor from nonpathogenic A. alternata. Each population of the toxin-producing fungi carried rDNA variants. Nine different types, named A1 to A6 and B1 to B3, were detected among the toxin-producing fungi and nonpathogenic A. alternata. All of the populations contained the type A4 variant, and the other rDNA types were also shared by different toxin-producing fungi and A. alternata. In contrast, Alternaria species that are morphologically distinguishable from A. alternata could be differentiated from A. alternata on the basis of the rDNA RFLPs. Polymorphisms in rDNA digested with HaeIII and MspI were also evaluated in 61 Alternaria strains. These restriction enzymes produced 31 variations among all of the samples. The seven toxin-producing fungi and nonpathogenic A. alternata could not be resolved by phylogenetic analysis based on the RFLPs, although they could be differentiated from the other Alternaria species studied. These results provide support for the hypothesis that Alternaria fungi known to produce host-specific toxins are intraspecific variants of A. alternata specialized in pathogenicity. Images PMID:16349367

  8. Fungal-specific transcription factor AbPf2 activates pathogenicity in Alternaria brassicicola

    SciTech Connect

    Cho, Yangrae; Ohm, Robin A.; Grigoriev, Igor V.; Srivastava, Akhil

    2012-12-03

    Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. To identify molecular determinants of pathogenicity, we created non-pathogenic mutants of a transcription factor-encoding gene, AbPf2. The frequency and timing of germination and appressorium formation on host plants were similar between the non-pathogenic abpf2 mutants and wild-type A. brassicicola. The mutants were also similar in vitro to wild-type A. brassicicola in terms of vegetative growth, conidium production, and responses to a phytoalexin, reactive oxygen species and osmolites. The hyphae of the mutants grew slowly but did not cause disease symptoms on the surface of host plants. Transcripts of the AbPf2 gene increased exponentially soon after wild-type conidia contacted their host plants . A small amount of AbPf2 protein, as monitored using GFP fusions, was present in young, mature conidia. The protein level decreased during saprophytic growth, but increased and was located primarily in fungal nuclei during pathogenesis. Levels of the proteins and transcripts sharply decreased following colonization of host tissues beyond the initial infection site. When expression of the transcription factor was induced in the wild-type during early pathogenesis, 106 fungal genes were also induced in the wild-type but not in the abpf2 mutants. Notably, 33 of the 106 genes encoded secreted proteins, including eight putative effector proteins. Plants inoculated with abpf2 mutants expressed higher levels of genes associated with photosynthesis, the pentose phosphate pathway and primary metabolism, but lower levels of defense-related genes. Our results suggest that AbPf2 is an important regulator of pathogenesis, but does not affect other cellular processes in A. brassicicola.

  9. Phylogenetic, morphological and pathogenic characterization of Alternaria species associated with fruit rots of blueberry in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fruit rot caused by Alternaria spp. is one of the most important factors affecting the postharvest quality and shelf life of blueberry fruits. Alternaria spp. isolates were collected from decayed fruits of blueberry in the Central Valley of California during 2012 and 2013. The aims of this study wer...

  10. Complex regulation of secondary metabolism controlling pathogenicity in the phytopathogenic fungus Alternaria alternata.

    PubMed

    Takaoka, Shinya; Kurata, Mariko; Harimoto, Yoshiaki; Hatta, Rieko; Yamamoto, Mikihiro; Akimitsu, Kazuya; Tsuge, Takashi

    2014-06-01

    The filamentous fungus Alternaria alternata includes seven pathogenic variants (pathotypes), which produce different host-selective toxins and cause disease on different plants. The Japanese pear, strawberry and tangerine pathotypes produce AK-toxin, AF-toxin and ACT-toxin, respectively, which have a common structural moiety, 9,10-epoxy-8-hydroxy-9-methyl-decatrienoic acid (EDA). Here, we identified a new gene, AKT7 (AK-toxin biosynthetic gene 7), from the Japanese pear pathotype, which encodes a cytochrome P450 monooxygenase and functions to limit AK-toxin production. AKT7 homologs were found in the strawberry pathotype, but not the tangerine pathotype. However, the strawberry pathotype homolog appeared to include a premature stop codon. Although the Japanese pear pathotype strain has multiple copies of AKT7, a single-copy disruption resulted in mutants with increased production of AK-toxin and EDA. AKT7 overexpression in the three pathotypes caused marked reductions of toxin and EDA production, suggesting that Akt7 catalyzes a side reaction of EDA or its precursor. AKT7 overexpression caused reduced virulence in these pathotypes. We also found that AKT7 transcripts predominantly include misspliced mRNAs, which have premature stop codons. Our observations suggest that the AK-toxin production required for full virulence is regulated in a complex way by the copy number and intron information content of AKT7. PMID:24611558

  11. Analysis of genetic and pathogenic variation among Alternaria solani in a potato production region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A two-year survey was conducted in a potato production region to investigate the genetic variability within naturally infecting populations of Alternaria solani, the cause of early blight in potato, and between species A. solani and A. dauci. Genetic diversity among 151 isolates was assessed using s...

  12. Effect of Alternaria solani exudates on resistant and susceptible potato cultivars from two different pathogen isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The resistance phenotypes of two potato cultivars to two isolates of Alternaria solani, causal agent of early blight, were studied under greenhouse conditions. The two isolates contain varying degrees of aggressiveness on both susceptible and resistant phenotypes of potatoes. A bioassay was used to ...

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

    DOEpatents

    Cary; R. Bruce; Stubben, Christopher J.

    2011-03-22

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

  14. The biochemical basis of pathogenicity and host-specificity of Penicillium digitatum on citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this work, we report that volatiles emitted from wounded citrus peel play a major role in host recognition by Penicillium digitatum. Volatiles of various citrus cultivars had a pronounced stimulatory effect on germination and germ tube elongation of green mold pathogen. When exposed to volatile...

  15. Characterization and Pathogenicity of Alternaria burnsii from Seeds of Cucurbita maxima (Cucurbitaceae) in Bangladesh.

    PubMed

    Paul, Narayan Chandra; Deng, Jian Xin; Lee, Hyang Burm; Yu, Seung-Hun

    2015-12-01

    In the course of survey of endophytic fungi from Bangladesh pumpkin seeds in 2011~2012, two strains (CNU111042 and CNU111043) with similar colony characteristics were isolated and characterized by their morphology and by molecular phylogenetic analysis of the internal transcribed spacer, glyceraldehydes-3-phosphate dehydrogenase (gpd), and Alternaria allergen a1 (Alt a1) sequences. Phylogenetic analysis of all three sequences and their combined dataset revealed that the fungus formed a subclade within the A. alternata clade, matching A. burnsi and showing differences with its other closely related Alternaria species, such as A. longipes, A. tomato, and A. tomaticola. Long ellipsoid, obclavate or ovoid beakless conidia, shorter and thinner conidial size (16~60 [90] × 6.5~14 [~16] µm) distinguish this fungus from other related species. These isolates showed more transverse septation (2~11) and less longitudinal septation (0~3) than did other related species. Moreover, the isolate did not produce any diffusible pigment on media. Therefore, our results reveal that the newly recorded fungus from a new host, Cucurbita maxima, is Alternaria burnsii Uppal, Patel & Kamat. PMID:26839497

  16. Characterization and Pathogenicity of Alternaria burnsii from Seeds of Cucurbita maxima (Cucurbitaceae) in Bangladesh

    PubMed Central

    Paul, Narayan Chandra; Deng, Jian Xin

    2015-01-01

    In the course of survey of endophytic fungi from Bangladesh pumpkin seeds in 2011~2012, two strains (CNU111042 and CNU111043) with similar colony characteristics were isolated and characterized by their morphology and by molecular phylogenetic analysis of the internal transcribed spacer, glyceraldehydes-3-phosphate dehydrogenase (gpd), and Alternaria allergen a1 (Alt a1) sequences. Phylogenetic analysis of all three sequences and their combined dataset revealed that the fungus formed a subclade within the A. alternata clade, matching A. burnsi and showing differences with its other closely related Alternaria species, such as A. longipes, A. tomato, and A. tomaticola. Long ellipsoid, obclavate or ovoid beakless conidia, shorter and thinner conidial size (16~60 [90] × 6.5~14 [~16] µm) distinguish this fungus from other related species. These isolates showed more transverse septation (2~11) and less longitudinal septation (0~3) than did other related species. Moreover, the isolate did not produce any diffusible pigment on media. Therefore, our results reveal that the newly recorded fungus from a new host, Cucurbita maxima, is Alternaria burnsii Uppal, Patel & Kamat. PMID:26839497

  17. Evaluation of a triplex real-time PCR system to detect the plant-pathogenic molds Alternaria spp., Fusarium spp. and C. purpurea.

    PubMed

    Grube, Sabrina; Schönling, Jutta; Prange, Alexander

    2015-12-01

    This article describes the development of a triplex real-time PCR system for the simultaneous detection of three major plant-pathogenic mold genera (Alternaria spp., Fusarium spp. and the species Claviceps purpurea). The designed genus-specific primer-probe systems were validated for sensitivity, specificity and amplification in the presence of background DNA. PMID:26545945

  18. AbSte7, a MAPKK Gene of Alternaria brassicicola, is Involved in Conidiation, Salt/Oxidative Stress, and Pathogenicity.

    PubMed

    Xu, Houjuan; Zhang, Qianqian; Cui, Wenjuan; Zhang, Xiaofei; Liu, Weiyang; Zhang, Li; Islam, Md Nurul; Baek, Kwang-Hyun; Wang, Yujun

    2016-07-28

    Alternaria brassicicola (Schwein.) invades Brassicaceae and causes black spot disease, significantly lowering productivity. Mitogen-activated protein kinases (MAPKs) and their upstream kinases, including MAPK kinases (MAPKKs) and MAPKK kinases (MAPKKK), comprise one of the most important signaling pathways determining the pathogenicity of diverse plant pathogens. The AbSte7 gene in the genome of A. brassicicola was predicted to be a homolog of yeast Ste7, a MAPKK; therefore, the function was characterized by generating null mutant strains with a gene replacement method. AbSte7 replacement mutants (RMs) had a slower growth rate and altered colony morphology compared with the wild-type strain. Disruption of the AbSte7 gene resulted in defects in conidiation and melanin accumulation. AbSte7 was also involved in the resistance pathways in salt and oxidative stress, working to negatively regulate salt tolerance and positively regulate oxidative stress. Pathogenicity assays revealed that AbSte7 RMs could not infect intact cabbage leaves, but only formed very small lesions in wounded leaves, whereas typical lesions appeared on both intact and wounded leaves inoculated with the wild-type strain. As the first studied MAPKK in A. brassicicola, these data strongly suggest that the AbSte7 gene is an essential element for the growth, development, and pathogenicity of A. brassicicola. PMID:27160581

  19. Discovery of a viral pathogen in the Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used a Metagenomics approach and discovered an insect-infecting virus in adult Asian citrus psyllids in Florida. Though wide spread in nature, this is the first report of a Fijivirus in North America. The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a small insect tha...

  20. Inhibition of citrus fungal pathogens by using lactic acid bacteria.

    PubMed

    Gerez, C L; Carbajo, M S; Rollán, G; Torres Leal, G; Font de Valdez, G

    2010-08-01

    The effect of lactic acid bacteria (LAB) on pathogenic fungi was evaluated and the metabolites involved in the antifungal effect were characterized. Penicillium digitatum (INTA 1 to INTA 7) and Geotrichum citri-aurantii (INTA 8) isolated from decayed lemon from commercial packinghouses were treated with imazalil and guazatine to obtain strains resistant to these fungicides. The most resistant strains (4 fungal strains) were selected for evaluating the antifungal activity of 33 LAB strains, among which only 8 strains gave positive results. The antifungal activity of these LAB strains was related to the production of lactic acid, acetic acid, and phenyllactic acid (PLA). A central composite design and the response surface methodology were used to evaluate the inhibitory effect of the organic acids produced by the LAB cultures. The antifungal activity of lactic acid was directly related to its concentration; however, acetic acid and PLA showed a peak of activity at 52.5 and 0.8 mM, respectively, with inhibition rates similar to those obtained with Serenade((R)) (3.0 ppm) imazalil (50 ppm) and guazatine (50 ppm). Beyond the peak of activity, a reduction in effectiveness of both acetic acid and PLA was observed. Comparing the inhibition rate of the organic acids, PLA was about 66- and 600-fold more effective than acetic acid and lactic acid, respectively. This study presents evidences on the antifungal effect of selected LAB strains and their end products. Studies are currently being undertaken to evaluate the effectiveness in preventing postharvest diseases on citrus fruits. PMID:20722936

  1. Rapid screening for citrus canker resistance employing pathogen-associated molecular pattern-triggered immunity responses

    PubMed Central

    Pitino, Marco; Armstrong, Cheryl M; Duan, Yongping

    2015-01-01

    Citrus canker, caused by the bacterial pathogen Xanthomonas citri ssp. citri (Xcc), has been attributed to millions of dollars in loss or damage to commercial citrus crops in subtropical production areas of the world. Since identification of resistant plants is one of the most effective methods of disease management, the ability to screen for resistant seedlings plays a key role in the production of a long-term solution to canker. Here, an inverse correlation between reactive oxygen species (ROS) production by the plant and the ability of Xcc to grow and form lesions on infected plants is reported. Based on this information, a novel screening method that can rapidly identify citrus seedlings that are less susceptible to early infection by Xcc was devised by measuring ROS accumulation triggered by a 22-amino acid sequence of the conserved N-terminal part of flagellin (flg22) from X. citri ssp. citri (Xcc-flg22). In addition to limiting disease symptoms, ROS production was also correlated with the expression of basal defense-related genes such as the pattern recognition receptors LRR8 and FLS2, the leucine-rich repeat receptor-like protein RLP12, and the defense-related gene PR1, indicating an important role for pathogen-associated molecular pattern-triggered immunity (PTI) in determining resistance to citrus canker. Moreover, the differential expression patterns observed amongst the citrus seedlings demonstrated the existence of genetic variations in the PTI response among citrus species/varieties. PMID:26504581

  2. Functional Analyses of the Diels-Alderase Gene sol5 of Ascochyta rabiei and Alternaria solani Indicate that the Solanapyrone Phytotoxins Are Not Required for Pathogenicity.

    PubMed

    Kim, Wonyong; Park, Chung-Min; Park, Jeong-Jin; Akamatsu, Hajime O; Peever, Tobin L; Xian, Ming; Gang, David R; Vandemark, George; Chen, Weidong

    2015-04-01

    Ascochyta rabiei and Alternaria solani, the causal agents of Ascochyta blight of chickpea (Cicer arietinum) and early blight of potato (Solanum tuberosum), respectively, produce a set of phytotoxic compounds including solanapyrones A, B, and C. Although both the phytotoxicity of solanapyrones and their universal production among field isolates have been documented, the role of solanapyrones in pathogenicity is not well understood. Here, we report the functional characterization of the sol5 gene, which encodes a Diels-Alderase that catalyzes the final step of solanapyrone biosynthesis. Deletion of sol5 in both Ascochyta rabiei and Alternaria solani completely prevented production of solanapyrones and led to accumulation of the immediate precursor compound, prosolanapyrone II-diol, which is not toxic to plants. Deletion of sol5 did not negatively affect growth rate or spore production in vitro, and led to overexpression of the other solanapyrone biosynthesis genes, suggesting a possible feedback regulation mechanism. Phytotoxicity tests showed that solanapyrone A is highly toxic to several legume species and Arabidopsis thaliana. Despite the apparent phytotoxicity of solanapyrone A, pathogenicity tests showed that solanapyrone-minus mutants of Ascochyta rabiei and Alternaria solani were equally virulent as their corresponding wild-type progenitors, suggesting that solanapyrones are not required for pathogenicity. PMID:25372118

  3. Alternaria section Alternaria: Species, formae speciales or pathotypes?

    PubMed Central

    Woudenberg, J.H.C.; Seidl, M.F.; Groenewald, J.Z.; de Vries, M.; Stielow, J.B.; Thomma, B.P.H.J.; Crous, P.W.

    2015-01-01

    The cosmopolitan fungal genus Alternaria consists of multiple saprophytic and pathogenic species. Based on phylogenetic and morphological studies, the genus is currently divided into 26 sections. Alternaria sect. Alternaria contains most of the small-spored Alternaria species with concatenated conidia, including important plant, human and postharvest pathogens. Species within sect. Alternaria have been mostly described based on morphology and / or host-specificity, yet molecular variation between them is minimal. To investigate whether the described morphospecies within sect. Alternaria are supported by molecular data, whole-genome sequencing of nine Alternaria morphospecies supplemented with transcriptome sequencing of 12 Alternaria morphospecies as well as multi-gene sequencing of 168 Alternaria isolates was performed. The assembled genomes ranged in size from 33.3–35.2 Mb within sect. Alternaria and from 32.0–39.1 Mb for all Alternaria genomes. The number of repetitive sequences differed significantly between the different Alternaria genomes; ranging from 1.4–16.5 %. The repeat content within sect. Alternaria was relatively low with only 1.4–2.7 % of repeats. Whole-genome alignments revealed 96.7–98.2 % genome identity between sect. Alternaria isolates, compared to 85.1–89.3 % genome identity for isolates from other sections to the A. alternata reference genome. Similarly, 1.4–2.8 % and 0.8–1.8 % single nucleotide polymorphisms (SNPs) were observed in genomic and transcriptomic sequences, respectively, between isolates from sect. Alternaria, while the percentage of SNPs found in isolates from different sections compared to the A. alternata reference genome was considerably higher; 8.0–10.3 % and 6.1–8.5 %. The topology of a phylogenetic tree based on the whole-genome and transcriptome reads was congruent with multi-gene phylogenies based on commonly used gene regions. Based on the genome and transcriptome data, a set of core

  4. Genetic variability of Brazilian isolates of Alternaria alternata detected by AFLP and RAPD techniques

    PubMed Central

    Dini-Andreote, Francisco; Pietrobon, Vivian Cristina; Andreote, Fernando Dini; Romão, Aline Silva; Spósito, Marcel Bellato; Araújo, Welington Luiz

    2009-01-01

    The Alternaria brown spot (ABS) is a disease caused in tangerine plants and its hybrids by the fungus Alternaria alternata f. sp. citri which has been found in Brazil since 2001. Due to the recent occurrence in Brazilian orchards, the epidemiology and genetic variability of this pathogen is still an issue to be addressed. Here it is presented a survey about the genetic variability of this fungus by the characterization of twenty four pathogenic isolates of A. alternata f. sp. citri from citrus plants and four endophytic isolates from mango (one Alternaria tenuissima and three Alternaria arborescens). The application of two molecular markers Random Amplified Polymorphic DNA (RAPD) and Amplified Fragment Length Polymorphism (AFLP) had revealed the isolates clustering in distinct groups when fingerprintings were analyzed by Principal Components Analysis (PCA). Despite the better assessment of the genetic variability through the AFLP, significant modifications in clusters components were not observed, and only slight shifts in the positioning of isolates LRS 39/3 and 25M were observed in PCA plots. Furthermore, in both analyses, only the isolates from lemon plants revealed to be clustered, differently from the absence of clustering for other hosts or plant tissues. Summarizing, both RAPD and AFLP analyses were both efficient to detect the genetic variability within the population of the pathogenic fungus Alternaria spp., supplying information on the genetic variability of this species as a basis for further studies aiming the disease control. PMID:24031413

  5. Inducible proteins in citrus rootstocks with different tolerance towards the root rot pathogen Phytophthora palmivora

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activities of defense-related proteins (ß-1,3-glucanases, chitinases and peroxidases) and concentrations of total soluble phenolics were measured in roots and leaves of uninfected and infected plants to investigate the response of different citrus rootstock genotypes to the root rot pathogen Phytoph...

  6. Effect of citrus pulp on the viability of Saccharomyces boulardii in the presence of enteric pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Saccharomyces cerevisiae subtype boulardii is frequently used as a dietary supplement to promote intestinal health and reduce the impact of growth of enteric pathogens in livestock, including cattle and swine. Citrus by-products are also fed as dietary supplements that have the additional benefit o...

  7. Metabolomic analysis of citrus infection by Candidatus Liberibacter reveals insight into pathogenicity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), considered the most serious citrus disease in the world, is associated with the non-culturable bacterium Candidatus Liberibacter asiaticus (Las). Infection by the pathogen leads to reduced plant vigor and productivity, and ultimately results in death of the infected tree. Additi...

  8. Genetic diversity of citrus bacterial canker pathogens preserved in herbarium specimens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus bacterial canker (CBC) caused by Xanthomonas axonopodis pv. citri (Xac) was first documented in India and Java in the mid 19th century. Since that time the known distribution of the disease has steadily increased. Concurrent with the dispersion of the pathogen, the diversity of described str...

  9. Characterization of a novel single-stranded RNA virus, closely related to fusariviruses, infecting the plant pathogenic fungus Alternaria brassicicola.

    PubMed

    Zhong, Jie; Shang, Hong Hong; Zhu, Chuan Xia; Zhu, Jun Zi; Zhu, Hong Jian; Hu, Yan; Gao, Bi Da

    2016-06-01

    The alternaria blackspot of rapeseed is one of the most prominent diseases of rapeseed. It is caused by three species of the genus Alternaria: Alternaria brassicicola, Alternaria brassicae, and Alternaria raphanin. Here we report a novel positive-sense RNA virus from an A. brassicicola strain 817-14. The virus has a 6639 nucleotide (nt) long genome, excluding a poly (A)-tail, and was predicted to contain three putative open reading frames (ORF1, ORF2, and ORF3). The large ORF1 encoded a 174-kDa polyprotein (composed of 1522 amino acid residues) containing a conserved RNA-dependent RNA polymerase (RdRp) domain and a helicase domain. The other two smaller ORFs encoded polypeptides with unknown function. Homology search and phylogenetic analysis, based on the RdRp and helicase domains, suggest that this virus is related to and grouped with Sclerotinia sclerotiorum fusarivirus 1 (SsFV1), Rosellinia necatrix fusarivirus 1 (RnFV1), Fusarium graminearum virus-DK21 (FgV1), and Penicillium roqueforti RNA mycovirus 1 (PrRV1), all of which belong to a newly proposed family Fusariviridae. For this study, we designed the virus as "Alternaria brassicicola fusarivirus 1" (AbFV1). Virus elimination revealed that AbFV1 has no conspicuous impact on the biological properties of its host. PMID:26707921

  10. Validation of high-throughput real time polymerase chain reaction assays for simultaneous detection of invasive citrus pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A number of economically important citrus pathogens are spread by nursery propagation, arthropod vector transmission and in advertent importation and dissemination of infected plants. For these reasons, citrus disease management and clean stock programs need to employ an economical and sensitive p...

  11. Structural and biochemical characteristics of citrus flowers associated with defence against a fungal pathogen.

    PubMed

    Marques, João Paulo Rodrigues; Amorim, Lilian; Silva-Junior, Geraldo José; Spósito, Marcel Bellato; Appezzato-da Gloria, Beatriz

    2014-01-01

    The constitutive characters of plants can be structural or biochemical and play an important role in their defence against pathogens. Citrus postbloom fruit drop (PFD) caused by Colletotrichum spp. is one of the most important fungal diseases of citrus. The pathogen infects the flowers, leading to premature fruit drop and reducing citrus production. However, flower buds smaller than 8 mm long are usually not infected by Colletotrichum spp. Thus, this study investigated whether there are constitutive mechanisms in flower buds related to Colletotrichum spp. infection. We studied flower buds that were 2, 3, 4, 8, 12 and 15 mm long and petals, after anthesis, of sweet orange 'Valência' using light and scanning electron microscopy and histochemistry. We evaluated the effect of volatile organic compounds (VOCs) in flowers (R-limonene and linalool) on the in vitro growth of Colletotrichum acutatum. We found that the arrangement of the epidermal papillae in the petal primordia, the occurrence of prismatic crystals and the distribution of oil glands are the main differences between buds smaller than 8 mm and buds 8-15 mm long. Osmophores at the tips of petals produced and accumulated phenols, terpenes and lipophilic compounds. Flower buds smaller than 8 mm long have constitutive structural and biochemical barriers to Colletotrichum spp. infection. In addition, this is the first time that osmophores have been reported in citrus. Our study shows that natural terpenes of Citrus flowers inhibit the fungal growth in vitro, highlighting the potential use of terpenes for the chemical control of PFD in citrus. PMID:25535209

  12. Structural and biochemical characteristics of citrus flowers associated with defence against a fungal pathogen

    PubMed Central

    Marques, João Paulo Rodrigues; Amorim, Lilian; Silva-Junior, Geraldo José; Spósito, Marcel Bellato; Appezzato-da Gloria, Beatriz

    2015-01-01

    The constitutive characters of plants can be structural or biochemical and play an important role in their defence against pathogens. Citrus postbloom fruit drop (PFD) caused by Colletotrichum spp. is one of the most important fungal diseases of citrus. The pathogen infects the flowers, leading to premature fruit drop and reducing citrus production. However, flower buds smaller than 8 mm long are usually not infected by Colletotrichum spp. Thus, this study investigated whether there are constitutive mechanisms in flower buds related to Colletotrichum spp. infection. We studied flower buds that were 2, 3, 4, 8, 12 and 15 mm long and petals, after anthesis, of sweet orange ‘Valência’ using light and scanning electron microscopy and histochemistry. We evaluated the effect of volatile organic compounds (VOCs) in flowers (R-limonene and linalool) on the in vitro growth of Colletotrichum acutatum. We found that the arrangement of the epidermal papillae in the petal primordia, the occurrence of prismatic crystals and the distribution of oil glands are the main differences between buds smaller than 8 mm and buds 8–15 mm long. Osmophores at the tips of petals produced and accumulated phenols, terpenes and lipophilic compounds. Flower buds smaller than 8 mm long have constitutive structural and biochemical barriers to Colletotrichum spp. infection. In addition, this is the first time that osmophores have been reported in citrus. Our study shows that natural terpenes of Citrus flowers inhibit the fungal growth in vitro, highlighting the potential use of terpenes for the chemical control of PFD in citrus. PMID:25535209

  13. Assessment of oligogalacturonide from citrus pectin as a potential antibacterial agent against foodborne pathogens.

    PubMed

    Wu, Ming-Chang; Li, Hui-chin; Wu, Po-Hua; Huang, Ping-Hsiu; Wang, Yuh-Tai

    2014-08-01

    Foodborne diseases are an important public health problem in the world. The bacterial resistance against presently used antibiotics is becoming a public health issue; hence, the discovery of new antimicrobial agents from natural sources attracts a lot of attention. Antibacterial activities of oligogalacturonide from commercial microbial pectic enzyme (CPE) treated citrus pectin, which exhibits antioxidant and antitumor activities, against 4 foodborne pathogens including Salmonella Typhimurium, Staphylococcus aureus, Listeria monocytogenes, and Pseudomonas aeruginosa was assessed. Pectin hydrolysates from CPE hydrolysis exhibited antibacterial activities. However, no antibacterial activity of pectin was observed. Citrus oligogalacturonide from 24-h hydrolysis exhibited bactericidal effect against all selected foodborne pathogens and displayed minimal inhibitory concentration at 37.5 μg/mL for P. aeruginosa, L. monocytogenes, and S. Typhimurium, and at 150.0 μg/mL for S. aureus. PMID:25048440

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

    PubMed

    Tabachnick, Walter J

    2015-06-01

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

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

    PubMed

    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. PMID:25231217

  16. Isolation and characterization of Aschersonia placenta from citrus orchards and its pathogenicity towards Dialeurodes citri (Ashmead).

    PubMed

    Wang, Pingping; Song, Xuhong; Zhang, Hongyu

    2013-02-01

    For selecting potential biological agents to control Dialeurodes citri, a major insect pest in China's citrus orchards, 75 native Aschersonia isolates were selected from infected whiteflies in citrus orchards and were evaluated for virulence to third instar nymphs of D. citri at a concentration of 1 × 10(6)conidia/ml. The mortality rates of D. citri varied from 0% to 72.70%. Among the 75 Aschersonia isolates, three (HB10, HB12 and ZJ9) were the most virulent and pathogenic to D. citri and caused more than 69% mortality. The 50% lethal concentration (LC(50)) values of them were 1.86 × 10(6), 3.40 × 10(6) and 6.81 × 10(6)conidia/ml, respectively. The three isolates also produced conidia abundantly on potato dextrose agar medium (3.95 × 10(6), 6.19 × 10(6) and 7.34 × 10(6)conidia/cm(2), respectively). They were identified to be Aschersonia placenta based on their morphological analysis. Phylogenetic analysis showed that these three highly virulent Aschersonia isolates belong to a strongly supported clade that includes two other A. placenta isolates obtained from Vietnam and Thailand. In summary, these results indicate the possibility of developing the three most virulent A. placenta isolates as microbiological control agents against citrus whitefly. PMID:23160084

  17. Ungual and cutaneous phaeohyphomycosis caused by Alternaria alternata and Alternaria chlamydospora.

    PubMed

    Singh, S M; Naidu, J; Pouranik, M

    1990-01-01

    Two cases of ungual and cutaneous phaeohyphomycosis caused by Alternaria alternata and Alternaria chlamydospora are described. Oxiconazole and amorolfine were most effective in vitro against A. alternata and A. chlamydospora respectively. This is the first report of A. chlamydospora as an opportunistic pathogen of skin. PMID:2148601

  18. The destructive citrus pathogen, ‘Candidatus Liberibacter asiaticus’ encodes a functional flagellin characteristic of a pathogen-associated molecular pattern

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is presently the most devastating citrus disease worldwide. As an intracellular plant pathogen and insect symbiont, the HLB bacterium, ‘Candidatus Liberibacter asiaticus’ (Las) retains the entire flagellum-encoding gene cluster in its significantly reduced genome. Las encodes a...

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

    PubMed

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

    2014-01-01

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

  20. Genetic Diversity and Pathogenicity of Xanthomonas axonopodis Strains Inducing Citrus Canker Disease in Iran and South Korea.

    PubMed

    Khodakaramian, G; Swings, J

    2011-06-01

    For the first time in 1989 citrus bacterial canker disease has seen on Citrusaurantiifolia in southern Iran. A total of 43 strains from affected citrus trees, ten strains from South Korea and representative from all known five pathotypes of Xanthomonas axonopodis pathogenic on citrus trees were used in this study. Isolated strains from Iran were indistinguishable by phenotypic, FAMEs, and SDS-PAGE analyses but showed different host range. First group were pathogenic on all tested citrus seedlings including C. aurantiifolia, C. limettioides, C. limon, C. jambhiri, Poncirus trifoliata X C. paradisi, C. aurantium, C. paradise, C. medica, P. trifoliate, C. grandis, C. sinensis, C. reticulate and C. sinensis X P. trifoliate. Pathogenicity of the second group were limited to C. aurantiifolia, C. limettioides, C. limon, C. jambhiri, P. trifoliata X C. paradis, and C. aurantium. Among the strains studied by AFLP fingerprinting six clusters were found. These clusters were: (1) strains of pathotype C; (2) strains of pathotypes B and D; (3) strains of pathotype A together with the main group of the Iranian strains; (4) strains isolated from Korea; (5) strains of pathotype E; and (6) seven strains from Iran which made a completely separate cluster. Strains from pathotypes B and D could not be differentiated by AFLP. The tested Iranian strains belongs to the two different groups and strains from Korea grouped as a subcluster from main cluster of Iranian strains belong to the pathotype A. PMID:22654164

  1. Analysis of alternariol and alternariol monomethyl ether on flavedo and albedo tissues of tangerines (Citrus reticulata) with symptoms of alternaria brown spot.

    PubMed

    Magnani, Rodrigo F; De Souza, Gezimar D; Rodrigues-Filho, Edson

    2007-06-27

    A method was developed for the quantification of alternariol and alternariol monomethyl ether on tangerines with and without symptoms of Alternaria brown spot disease. The method employs solid-phase extraction for cleanup, followed by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) for detection. This method was validated on flavedo (exocarp or epicarp, exterior yellow peel) and on albedo tissue (mesocarp, interior white peel). An excellent linearity over a range of 0.50-20.0 mg/kg was achieved, with r2 >or= 0.997. The limits of detection (LOD) and quantification (LOQ) were fewer than 0.13 and 0.50 microg/kg, respectively. The relative standard deviations (RSDs) were

  2. Insecticidal Suppression of Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae) Vector of Huanglongbing Pathogens

    PubMed Central

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

    2014-01-01

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

  3. Infection Density Dynamics of the Citrus Greening Bacterium "Candidatus Liberibacter asiaticus" in Field Populations of the Psyllid Diaphorina citri and Its Relevance to the Efficiency of Pathogen Transmission to Citrus Plants.

    PubMed

    Ukuda-Hosokawa, Rie; Sadoyama, Yasutsune; Kishaba, Misaki; Kuriwada, Takashi; Anbutsu, Hisashi; Fukatsu, Takema

    2015-06-01

    Huanglongbing, or citrus greening, is a devastating disease of citrus plants recently spreading worldwide, which is caused by an uncultivable bacterial pathogen, "Candidatus Liberibacter asiaticus," and vectored by a phloem-sucking insect, Diaphorina citri. We investigated the infection density dynamics of "Ca. Liberibacter asiaticus" in field populations of D. citri with experiments using field-collected insects to address how "Ca. Liberibacter asiaticus" infection density in the vector insect is relevant to pathogen transmission to citrus plants. Of 500 insects continuously collected from "Ca. Liberibacter asiaticus"-infected citrus trees with pathological symptoms in the spring and autumn of 2009, 497 (99.4%) were "Ca. Liberibacter asiaticus" positive. The infections were systemic across head-thorax and abdomen, ranging from 10(3) to 10(7) bacteria per insect. In spring, the infection densities were low in March, at ∼ 10(3) bacteria per insect, increasing up to 10(6) to 10(7) bacteria per insect in April and May, and decreasing to 10(5) to 10(6) bacteria per insect in late May, whereas the infection densities were constantly ∼ 10(6) to 10(7) bacteria per insect in autumn. Statistical analysis suggested that several factors, such as insect sex, host trees, and collection dates, may be correlated with "Ca. Liberibacter asiaticus" infection densities in field D. citri populations. Inoculation experiments with citrus seedlings using field-collected "Ca. Liberibacter asiaticus"-infected insects suggested that (i) "Ca. Liberibacter asiaticus"-transmitting insects tend to exhibit higher infection densities than do nontransmitting insects, (ii) a threshold level (∼ 10(6) bacteria per insect) of "Ca. Liberibacter asiaticus" density in D. citri is required for successful transmission to citrus plants, and (iii) D. citri attaining the threshold infection level transmits "Ca. Liberibacter asiaticus" to citrus plants in a stochastic manner. These findings provide

  4. Infection Density Dynamics of the Citrus Greening Bacterium “Candidatus Liberibacter asiaticus” in Field Populations of the Psyllid Diaphorina citri and Its Relevance to the Efficiency of Pathogen Transmission to Citrus Plants

    PubMed Central

    Ukuda-Hosokawa, Rie; Sadoyama, Yasutsune; Kishaba, Misaki; Kuriwada, Takashi; Anbutsu, Hisashi

    2015-01-01

    Huanglongbing, or citrus greening, is a devastating disease of citrus plants recently spreading worldwide, which is caused by an uncultivable bacterial pathogen, “Candidatus Liberibacter asiaticus,” and vectored by a phloem-sucking insect, Diaphorina citri. We investigated the infection density dynamics of “Ca. Liberibacter asiaticus” in field populations of D. citri with experiments using field-collected insects to address how “Ca. Liberibacter asiaticus” infection density in the vector insect is relevant to pathogen transmission to citrus plants. Of 500 insects continuously collected from “Ca. Liberibacter asiaticus”-infected citrus trees with pathological symptoms in the spring and autumn of 2009, 497 (99.4%) were “Ca. Liberibacter asiaticus” positive. The infections were systemic across head-thorax and abdomen, ranging from 103 to 107 bacteria per insect. In spring, the infection densities were low in March, at ∼103 bacteria per insect, increasing up to 106 to 107 bacteria per insect in April and May, and decreasing to 105 to 106 bacteria per insect in late May, whereas the infection densities were constantly ∼106 to 107 bacteria per insect in autumn. Statistical analysis suggested that several factors, such as insect sex, host trees, and collection dates, may be correlated with “Ca. Liberibacter asiaticus” infection densities in field D. citri populations. Inoculation experiments with citrus seedlings using field-collected “Ca. Liberibacter asiaticus”-infected insects suggested that (i) “Ca. Liberibacter asiaticus”-transmitting insects tend to exhibit higher infection densities than do nontransmitting insects, (ii) a threshold level (∼106 bacteria per insect) of “Ca. Liberibacter asiaticus” density in D. citri is required for successful transmission to citrus plants, and (iii) D. citri attaining the threshold infection level transmits “Ca. Liberibacter asiaticus” to citrus plants in a stochastic manner. These

  5. Elucidation of the biochemical basis of specificity and pathogenicity of Penicillium digitatum on citrus fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Green mold caused by Penicillium digitatum is the most damaging postharvest diseases of citrus fruit. This Penicillium species is specific to citrus fruit and do not cause progressive decay in any other fresh fruit or vegetable crops. While the etiology of P. digitatum is well understood, the phys...

  6. Expression of ß-1,3-glucanase and ß-1,4-glucanase in two potato cultivars following challenge by the fungal pathogen Alternaria solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early blight of potato, caused by Alternaria solani, is a ubiquitous disease in many countries around the world. We have previously found that variation in resistance phenotypes exist between two different Iranian cultivars of potato. Cultivar ‘Diamond’ is more resistant to multiple isolates of A. s...

  7. Functional analyses of the Diels-Alderase gene sol5 of Ascochyta rabiei and Alternaria solani indicate that the Solanapyrone phytotoxins are not required for pathogenicity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ascochyta rabiei and Alternaria solani, the causal agents of Ascochyta blight of chickpea (Cicer arietinum) and early blight of potato (Solanum tuberosum), respectively, produce a set of phytotoxic compounds incuding solanapyrones A, B, and C. Although both the phytotoxicity of solanopyrones and the...

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

    PubMed Central

    2014-01-01

    Background 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. Results 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. Conclusions 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

  9. Prophage-Mediated Dynamics of ‘Candidatus Liberibacter asiaticus’ Populations, the Destructive Bacterial Pathogens of Citrus Huanglongbing

    PubMed Central

    Zhou, Lijuan; Powell, Charles A.; Li, Wenbin; Irey, Mike; Duan, Yongping

    2013-01-01

    Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus’ (Las) Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB), a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by screening clone libraries of infected citrus, periwinkle and psyllids. Among them, Types A and B share highly conserved sequences and localize within the two prophages, FP1 and FP2, respectively. Although Types B and C were abundant in all three libraries, Type A was much more abundant in the libraries from the Las-infected psyllids than from the Las-infected plants, and Type D was only identified in libraries from the infected host plants but not from the infected psyllids. Sequence analysis of these variants revealed that the variations may result from recombination and rearrangement events. Conventional PCR results using type-specific molecular markers indicated that A, B, C and D are the four most abundant types in Las-infected citrus and periwinkle. However, only three types, A, B and C are abundant in Las-infected psyllids. Typing results for Las-infected citrus field samples indicated that mixed populations of Las bacteria present in Floridian isolates, but only the Type D population was correlated with the blotchy mottle symptom. Extended cloning and sequencing of the Type D region revealed a third prophage/phage in the Las genome, which may derive from the recombination of FP1 and FP2. Dramatic variations in these prophage regions were also found among the global Las isolates. These results are the first to demonstrate the prophage/phage-mediated dynamics of Las populations in plant and insect hosts, and their correlation with insect transmission and disease

  10. Fungicidal activity of silver nanoparticles against Alternaria brassicicola

    NASA Astrophysics Data System (ADS)

    Gupta, Deepika; Chauhan, Pratima

    2016-04-01

    This work highlighted the fungicidal properties of silver nanoparticles against Alternaria brassicicola. Alternaria brassicicola causes Black spot of Cauliflower, radish, cabbage, kale which results in sever agricultural loss. We treat the synthesised silver nanoparticles (AgNPs) of 10, 25, 50, 100 and 110 ppm concentrations against Alternaria brassicicola on PDA containing Petri dish. We calculated inhibitory rate (%) in order to evaluate the antifungal efficacy of silver nanoparticles against pathogens. Treatment with 100ppm AgNPs resulted in maximum inhibition of Alternaria brassicicola i.e.92.2%. 110ppm of AgNPS also shows the same result, therefore 100ppm AgNPs was treated as optimize concentration. AgNPs effectively inhibited the growth of a Alternaria brassicicola, which suggests that AgNPs could be used as fungicide in plant disease management. Further research and development are necessary to translate this technology into plant disease management strategies.

  11. Discord between morphological and phylogenetic species boundaries: incomplete lineage sorting and recombination results in fuzzy species boundaries in an asexual fungal pathogen

    PubMed Central

    2014-01-01

    Background Traditional morphological and biological species concepts are difficult to apply to closely related, asexual taxa because of the lack of an active sexual phase and paucity of morphological characters. Phylogenetic species concepts such as genealogical concordance phylogenetic species recognition (GCPSR) have been extensively used; however, methods that incorporate gene tree uncertainty into species recognition may more accurately and objectively delineate species. Using a worldwide sample of Alternaria alternata sensu lato, causal agent of citrus brown spot, the evolutionary histories of four nuclear loci including an endo-polygalacturonase gene, two anonymous loci, and one microsatellite flanking region were estimated using the coalescent. Species boundaries were estimated using several approaches including those that incorporate uncertainty in gene genealogies when lineage sorting and non-reciprocal monophyly of gene trees is common. Results Coalescent analyses revealed three phylogenetic lineages strongly influenced by incomplete lineage sorting and recombination. Divergence of the citrus 2 lineage from the citrus 1 and citrus 3 lineages was supported at most loci. A consensus of species tree estimation methods supported two species of Alternaria causing citrus brown spot worldwide. Based on substitution rates at the endo-polygalacturonase locus, divergence of the citrus 2 and the 1 and 3 lineages was estimated to have occurred at least 5, 400 years before present, predating the human-mediated movement of citrus and associated pathogens out of SE Asia. Conclusions The number of Alternaria species identified as causing brown spot of citrus worldwide using morphological criteria has been overestimated. Little support was found for most of these morphospecies using quantitative species recognition approaches. Correct species delimitation of plant-pathogenic fungi is critical for understanding the evolution of pathogenicity, introductions of pathogens to

  12. Biotransformations of 6',7'-dihydroxybergamottin and 6',7'-epoxybergamottin by the citrus-pathogenic fungi diminish cytochrome P450 3A4 inhibitory activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Penicillium digitatum, as well as five other citrus pathogenic species, (P. ulaiense Link, Geotrichum citri Link, Botrytis cinerea P. Micheli ex Pers., Lasiodiplodia theobromae (Pat.)Griffon & Maubl. and Phomopsis citri (teleomorph Diaporthe citri)) was observed to convert 6',7'-epoxybergamottin (1)...

  13. Alternaria in Food: Ecophysiology, Mycotoxin Production and Toxicology

    PubMed Central

    Patriarca, Andrea; Magan, Naresh

    2015-01-01

    Alternaria species are common saprophytes or pathogens of a wide range of plants pre- and post-harvest. This review considers the relative importance of Alternaria species, their ecology, competitiveness, production of mycotoxins and the prevalence of the predominant mycotoxins in different food products. The available toxicity data on these toxins and the potential future impacts of Alternaria species and their toxicity in food products pre- and post-harvest are discussed. The growth of Alternaria species is influenced by interacting abiotic factors, especially water activity (aw), temperature and pH. The boundary conditions which allow growth and toxin production have been identified in relation to different matrices including cereal grain, sorghum, cottonseed, tomato, and soya beans. The competitiveness of Alternaria species is related to their water stress tolerance, hydrolytic enzyme production and ability to produce mycotoxins. The relationship between A. tenuissima and other phyllosphere fungi has been examined and the relative competitiveness determined using both an Index of Dominance (ID) and the Niche Overlap Index (NOI) based on carbon-utilisation patterns. The toxicology of some of the Alternaria mycotoxins have been studied; however, some data are still lacking. The isolation of Alternaria toxins in different food products including processed products is reviewed. The future implications of Alternaria colonization/infection and the role of their mycotoxins in food production chains pre- and post-harvest are discussed. PMID:26190916

  14. Alternaria in Food: Ecophysiology, Mycotoxin Production and Toxicology.

    PubMed

    Lee, Hyang Burm; Patriarca, Andrea; Magan, Naresh

    2015-06-01

    Alternaria species are common saprophytes or pathogens of a wide range of plants pre- and post-harvest. This review considers the relative importance of Alternaria species, their ecology, competitiveness, production of mycotoxins and the prevalence of the predominant mycotoxins in different food products. The available toxicity data on these toxins and the potential future impacts of Alternaria species and their toxicity in food products pre- and post-harvest are discussed. The growth of Alternaria species is influenced by interacting abiotic factors, especially water activity (aw), temperature and pH. The boundary conditions which allow growth and toxin production have been identified in relation to different matrices including cereal grain, sorghum, cottonseed, tomato, and soya beans. The competitiveness of Alternaria species is related to their water stress tolerance, hydrolytic enzyme production and ability to produce mycotoxins. The relationship between A. tenuissima and other phyllosphere fungi has been examined and the relative competitiveness determined using both an Index of Dominance (ID) and the Niche Overlap Index (NOI) based on carbon-utilisation patterns. The toxicology of some of the Alternaria mycotoxins have been studied; however, some data are still lacking. The isolation of Alternaria toxins in different food products including processed products is reviewed. The future implications of Alternaria colonization/infection and the role of their mycotoxins in food production chains pre- and post-harvest are discussed. PMID:26190916

  15. Bacterial Diversity Analysis of Huanglongbing Pathogen-Infected Citrus, Using PhyloChip Arrays and 16S rRNA Gene Clone Library Sequencing▿ †

    PubMed Central

    Sagaram, Uma Shankar; DeAngelis, Kristen M.; Trivedi, Pankaj; Andersen, Gary L.; Lu, Shi-En; Wang, Nian

    2009-01-01

    The bacterial diversity associated with citrus leaf midribs was characterized for citrus groves that contained the Huanglongbing (HLB) pathogen, which has yet to be cultivated in vitro. We employed a combination of high-density phylogenetic 16S rRNA gene microarrays and 16S rRNA gene clone library sequencing to determine the microbial community composition for symptomatic and asymptomatic citrus midribs. Our results revealed that citrus leaf midribs can support a diversity of microbes. PhyloChip analysis indicated that 47 orders of bacteria in 15 phyla were present in the citrus leaf midribs, while 20 orders in 8 phyla were observed with the cloning and sequencing method. PhyloChip arrays indicated that nine taxa were significantly more abundant in symptomatic midribs than in asymptomatic midribs. “Candidatus Liberibacter asiaticus” was detected at a very low level in asymptomatic plants but was over 200 times more abundant in symptomatic plants. The PhyloChip analysis results were further verified by sequencing 16S rRNA gene clone libraries, which indicated the dominance of “Candidatus Liberibacter asiaticus” in symptomatic leaves. These data implicate “Candidatus Liberibacter asiaticus” as the pathogen responsible for HLB disease. PMID:19151177

  16. Bridgehead invasion of a monomorphic plant pathogenic bacterium: Xanthomonas citri pv. citri, an emerging citrus pathogen in Mali and Burkina Faso.

    PubMed

    Leduc, A; Traoré, Y N; Boyer, K; Magne, M; Grygiel, P; Juhasz, C C; Boyer, C; Guerin, F; Wonni, I; Ouedraogo, L; Vernière, C; Ravigné, V; Pruvost, O

    2015-11-01

    Molecular epidemiology studies further our understanding of migrations of phytopathogenic bacteria, the major determining factor in their emergence. Asiatic citrus canker, caused by Xanthomonas citri pv. citri, was recently reported in Mali and Burkina Faso, a region remote from other contaminated areas. To identify the origin and pathways of these emergences, we used two sets of markers, minisatellites and microsatellites, for investigating different evolutionary scales. Minisatellite typing suggested the introduction of two groups of strains in Mali (DAPC 1 and DAPC 2), consistent with microsatellite typing. DAPC 2 was restricted to Bamako district, whereas DAPC 1 strains were found much more invasive. The latter strains formed a major clonal complex based on microsatellite data with the primary and secondary founders detected in commercial citrus nurseries and orchards. This suggests that human activities played a major role in the spread of DAPC 1 strains via the movement of contaminated propagative material, further supported by the frequent lack of differentiation between populations from geographically distant nurseries and orchards. Approximate Bayesian Computation analyses supported the hypothesis that strains from Burkina Faso resulted from a bridgehead invasion from Mali. Multi-locus variable number of tandem repeat analysis and Approximate Bayesian Computation are useful for understanding invasion routes and pathways of monomorphic bacterial pathogens. PMID:25866121

  17. The Destructive Citrus Pathogen, ‘Candidatus Liberibacter asiaticus’ Encodes a Functional Flagellin Characteristic of a Pathogen-Associated Molecular Pattern

    PubMed Central

    Zou, Huasong; Gowda, Siddarame; Zhou, Lijuan; Hajeri, Subhas; Chen, Gongyou; Duan, Yongping

    2012-01-01

    Huanglongbing (HLB) is presently the most devastating citrus disease worldwide. As an intracellular plant pathogen and insect symbiont, the HLB bacterium, ‘Candidatus Liberibacter asiaticus’ (Las), retains the entire flagellum-encoding gene cluster in its significantly reduced genome. Las encodes a flagellin and hook-associated protein (Fla) of 452 amino acids that contains a conserved 22 amino acid domain (flg22) at positions 29 to 50 in the N-terminus. The phenotypic alteration in motility of a Sinorhizobium meliloti mutant lacking the fla genes was partially restored by constitutive expression of FlaLas. Agrobacterium-mediated transient expression in planta revealed that FlaLas induced cell death and callose deposition in Nicotiana benthamiana, and that the transcription of BAK1 and SGT1, which are associated with plant innate immunity, was upregulated. Amino acid substitution experiments revealed that residues 38 (serine) and 39 (aspartate) of FlaLas were essential for callose induction. The synthetic flg22Las peptide could not induce plant cell death but retained the ability to induce callose deposition at a concentration of 20 µM or above. This demonstrated that the pathogen-associated molecular pattern (PAMP) activity of flg22 in Las was weaker than those in other well-studied plant pathogenic bacteria. These results indicate that FlaLas acts as a PAMP and may play an important role in triggering host plant resistance to the HLB bacteria. PMID:23029520

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

    PubMed Central

    Song, Min-A; Park, Jae Sin; Kim, Ki Deok; Jeun, Yong Chull

    2015-01-01

    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. PMID:26672670

  19. Development of a Loop-Mediated Isothermal Amplification Assay for Rapid and Specific Identification of ACT Producing Alternaria alternata, the Agent of Brown Spot Disease in Tangerine.

    PubMed

    Moghimi, Hamid; Moradi, Amir; Hamedi, Javad; Basiri, Mina

    2016-03-01

    Rapid, accurate, and easy identification of pathogenic agents has always been important in medicine, veterinary, and agriculture. The brown spot infection is among the most common diseases in tangerine caused by Alternaria alternata. Due to the existence of seven various pathotypes of A. alternata species, it is challenging and time consuming to detect a pathotype responsible for citrus brown spot. In this study, we were seeking a rapid and specific approach to identify the tangerine pathotype within the A. alternata-pathogenic species, using the loop-mediated isothermal amplification (LAMP) method and actts2 gene as a marker molecule. Nine pathogenic samples were obtained from the region of Ramsar, Iran, and certified as A. alternata-pathogenic isolates. Specific primers were designed for regions coding for Alternaria citri toxin (ACT), and the PCR and LAMP reactions were performed. Our data showed that the primers designed for the tangerine pathotype of A. alternata were specific, and in both reactions, positive results were only observed in desired pathotypes. In the other pathotypes of this species as well as other standard fungal samples as negative controls, no positive result was observed. Therefore, our results suggest the possibility to detect the tangerine-specific A. alternata pathotype from other related species with a high accuracy and in early stages of the disease. PMID:26638210

  20. Genomic and transcriptomic analyses of the tangerine pathotype of Alternaria alternata in response to oxidative stress.

    PubMed

    Wang, Mingshuang; Sun, Xuepeng; Yu, Dongliang; Xu, Jianping; Chung, Kuangren; Li, Hongye

    2016-01-01

    The tangerine pathotype of Alternaria alternata produces the A. citri toxin (ACT) and is the causal agent of citrus brown spot that results in significant yield losses worldwide. Both the production of ACT and the ability to detoxify reactive oxygen species (ROS) are required for A. alternata pathogenicity in citrus. In this study, we report the 34.41 Mb genome sequence of strain Z7 of the tangerine pathotype of A. alternata. The host selective ACT gene cluster in strain Z7 was identified, which included 25 genes with 19 of them not reported previously. Of these, 10 genes were present only in the tangerine pathotype, representing the most likely candidate genes for this pathotype specialization. A transcriptome analysis of the global effects of H2O2 on gene expression revealed 1108 up-regulated and 498 down-regulated genes. Expressions of those genes encoding catalase, peroxiredoxin, thioredoxin and glutathione were highly induced. Genes encoding several protein families including kinases, transcription factors, transporters, cytochrome P450, ubiquitin and heat shock proteins were found associated with adaptation to oxidative stress. Our data not only revealed the molecular basis of ACT biosynthesis but also provided new insights into the potential pathways that the phytopathogen A. alternata copes with oxidative stress. PMID:27582273

  1. Genomic and transcriptomic analyses of the tangerine pathotype of Alternaria alternata in response to oxidative stress

    PubMed Central

    Wang, Mingshuang; Sun, Xuepeng; Yu, Dongliang; Xu, Jianping; Chung, Kuangren; Li, Hongye

    2016-01-01

    The tangerine pathotype of Alternaria alternata produces the A. citri toxin (ACT) and is the causal agent of citrus brown spot that results in significant yield losses worldwide. Both the production of ACT and the ability to detoxify reactive oxygen species (ROS) are required for A. alternata pathogenicity in citrus. In this study, we report the 34.41 Mb genome sequence of strain Z7 of the tangerine pathotype of A. alternata. The host selective ACT gene cluster in strain Z7 was identified, which included 25 genes with 19 of them not reported previously. Of these, 10 genes were present only in the tangerine pathotype, representing the most likely candidate genes for this pathotype specialization. A transcriptome analysis of the global effects of H2O2 on gene expression revealed 1108 up-regulated and 498 down-regulated genes. Expressions of those genes encoding catalase, peroxiredoxin, thioredoxin and glutathione were highly induced. Genes encoding several protein families including kinases, transcription factors, transporters, cytochrome P450, ubiquitin and heat shock proteins were found associated with adaptation to oxidative stress. Our data not only revealed the molecular basis of ACT biosynthesis but also provided new insights into the potential pathways that the phytopathogen A. alternata copes with oxidative stress. PMID:27582273

  2. Bacterial diversity analysis of Huanglongbing pathogen-infected citrus, using PhyloChip and 16S rRNA gene clone library sequencing

    SciTech Connect

    Shankar Sagaram, U.; DeAngelis, K.M.; Trivedi, P.; Andersen, G.L.; Lu, S.-E.; Wang, N.

    2009-03-01

    The bacterial diversity associated with citrus leaf midribs was characterized 1 from citrus groves that contained the Huanglongbing (HLB) pathogen, which has yet to be cultivated in vitro. We employed a combination of high-density phylogenetic 16S rDNA microarray and 16S rDNA clone library sequencing to determine the microbial community composition of symptomatic and asymptomatic citrus midribs. Our results revealed that citrus leaf midribs can support a diversity of microbes. PhyloChip analysis indicated that 47 orders of bacteria from 15 phyla were present in the citrus leaf midribs while 20 orders from phyla were observed with the cloning and sequencing method. PhyloChip arrays indicated that nine taxa were significantly more abundant in symptomatic midribs compared to asymptomatic midribs. Candidatus Liberibacter asiaticus (Las) was detected at a very low level in asymptomatic plants, but was over 200 times more abundant in symptomatic plants. The PhyloChip analysis was further verified by sequencing 16S rDNA clone libraries, which indicated the dominance of Las in symptomatic leaves. These data implicate Las as the pathogen responsible for HLB disease. Citrus is the most important commercial fruit crop in Florida. In recent years, citrus Huanglongbing (HLB), also called citrus greening, has severely affected Florida's citrus production and hence has drawn an enormous amount of attention. HLB is one of the most devastating diseases of citrus (6,13), characterized by blotchy mottling with green islands on leaves, as well as stunting, fruit decline, and small, lopsided fruits with poor coloration. The disease tends to be associated with a phloem-limited fastidious {alpha}-proteobacterium given a provisional Candidatus status (Candidatus Liberobacter spp. later changed to Candidatus Liberibacter spp.) in nomenclature (18,25,34). Previous studies indicate that HLB infection causes disorder in the phloem and severely impairs the translocation of assimilates in host

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

    PubMed Central

    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

  4. Development of a High Throughput Assay for Rapid and Accurate 10-Plex Detection of Citrus Pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The need to reliably detect and identify multiple plant pathogens simultaneously, especially in woody perennial hosts, has led to development of new molecular diagnostic approaches. In this study, a Luminex-based system was developed that provided a robust and sensitive test for simultaneous detect...

  5. Genome sequence of the necrotrophic fungus Penicillium digitatum, the main postharvest pathogen of citrus

    PubMed Central

    2012-01-01

    Background Penicillium digitatum is a fungal necrotroph causing a common citrus postharvest disease known as green mold. In order to gain insight into the genetic bases of its virulence mechanisms and its high degree of host-specificity, the genomes of two P. digitatum strains that differ in their antifungal resistance traits have been sequenced and compared with those of 28 other Pezizomycotina. Results The two sequenced genomes are highly similar, but important differences between them include the presence of a unique gene cluster in the resistant strain, and mutations previously shown to confer fungicide resistance. The two strains, which were isolated in Spain, and another isolated in China have identical mitochondrial genome sequences suggesting a recent worldwide expansion of the species. Comparison with the closely-related but non-phytopathogenic P. chrysogenum reveals a much smaller gene content in P. digitatum, consistent with a more specialized lifestyle. We show that large regions of the P. chrysogenum genome, including entire supercontigs, are absent from P. digitatum, and that this is the result of large gene family expansions rather than acquisition through horizontal gene transfer. Our analysis of the P. digitatum genome is indicative of heterothallic sexual reproduction and reveals the molecular basis for the inability of this species to assimilate nitrate or produce the metabolites patulin and penicillin. Finally, we identify the predicted secretome, which provides a first approximation to the protein repertoire used during invasive growth. Conclusions The complete genome of P. digitatum, the first of a phytopathogenic Penicillium species, is a valuable tool for understanding the virulence mechanisms and host-specificity of this economically important pest. PMID:23171342

  6. Occurrence of Leaf Blight on Cosmos Caused by Alternaria cosmosa in Korea

    PubMed Central

    Deng, Jian Xin; Lee, Ji Hye; Paul, Narayan Chandra; Cho, Hye Sun; Lee, Hyang Burm; Yu, Seung Hun

    2015-01-01

    In 2011, a leaf blight disease was observed on cosmos (Cosmos bipinnatus) leaves in Nonsan, Korea. The causal pathogen was isolated and identified based on morphological and molecular approaches. Morphological characteristics of the pathogen matched well with the Alternaria cosmosa and also easily distinguishable from Alternaria zinniae reported from cosmos seeds by producing branched beak. Phylogenetically, the pathogen could not be distinguished from A. passiflorae based on the sequence analysis of a combined data set of Alt a1 and gpd genes. However, A. passiflorae was distinguished from the present species by having conidiophores with 4 to 5 conidiogenous loci. The results indicate that the present Alternaria species is A. cosmosa. Pathogenicity tests revealed that the isolate was pathogenic to the leaves of Cosmos bipinnatus. This is the first report of Alternaria blight disease caused by A. cosmosa on cosmos in Korea. PMID:25774114

  7. Serological detection of ‘Candidatus Liberibacter asiaticus’ in citrus, and identification by GeLC-MS/MS of a chaperone protein responding to cellular pathogens

    PubMed Central

    Ding, Fang; Duan, Yongping; Yuan, Qing; Shao, Jonathan; Hartung, John S.

    2016-01-01

    We describe experiments with antibodies against ‘Candidatus Liberibacter asiaticus used to detect the pathogen in infected plants. We used scFv selected to bind epitopes exposed on the surface of the bacterium in tissue prints, with secondary monoclonal antibodies directed at a FLAG epitope included at the carboxyl end of the scFv. Unexpectedly, the anti-FLAG secondary antibody produced positive results with CaLas diseased samples when the primary scFv were not used. The anti-FLAG monoclonal antibody (Mab) also identified plants infected with other vascular pathogens. We then identified a paralogous group of secreted chaperone proteins in the HSP-90 family that contained the amino acid sequence DDDDK identical to the carboxy-terminal sequence of the FLAG epitope. A rabbit polyclonal antibody against one of the same epitopes combined with a goat anti-rabbit secondary antibody produced very strong purple color in individual phloem cells, as expected for this pathogen. These results were entirely specific for CaLas-infected citrus. The simplicity, cost and ability to scale the tissue print assay makes this an attractive assay to complement PCR-based assays currently in use. The partial FLAG epitope may itself be useful as a molecular marker for the rapid screening of citrus plants for the presence of vascular pathogens. PMID:27381064

  8. Serological detection of 'Candidatus Liberibacter asiaticus' in citrus, and identification by GeLC-MS/MS of a chaperone protein responding to cellular pathogens.

    PubMed

    Ding, Fang; Duan, Yongping; Yuan, Qing; Shao, Jonathan; Hartung, John S

    2016-01-01

    We describe experiments with antibodies against 'Candidatus Liberibacter asiaticus used to detect the pathogen in infected plants. We used scFv selected to bind epitopes exposed on the surface of the bacterium in tissue prints, with secondary monoclonal antibodies directed at a FLAG epitope included at the carboxyl end of the scFv. Unexpectedly, the anti-FLAG secondary antibody produced positive results with CaLas diseased samples when the primary scFv were not used. The anti-FLAG monoclonal antibody (Mab) also identified plants infected with other vascular pathogens. We then identified a paralogous group of secreted chaperone proteins in the HSP-90 family that contained the amino acid sequence DDDDK identical to the carboxy-terminal sequence of the FLAG epitope. A rabbit polyclonal antibody against one of the same epitopes combined with a goat anti-rabbit secondary antibody produced very strong purple color in individual phloem cells, as expected for this pathogen. These results were entirely specific for CaLas-infected citrus. The simplicity, cost and ability to scale the tissue print assay makes this an attractive assay to complement PCR-based assays currently in use. The partial FLAG epitope may itself be useful as a molecular marker for the rapid screening of citrus plants for the presence of vascular pathogens. PMID:27381064

  9. Transcriptomic profile of tobacco in response to Alternaria longipes and Alternaria alternata infections

    PubMed Central

    Duan, Shengchang; Ma, Xiao; Chen, Wei; Wan, Wenting; He, Yuqi; Ma, Xiaoqin; Ma, Yujin; Long, Ni; Tan, Yuntao; Wang, Yangzi; Hou, Yujie; Dong, Yang

    2016-01-01

    Tobacco brown spot caused by Alternaria fungal species is one of the most damaging diseases, and results in significant yield losses. However, little is known about the systematic response of tobacco to this fungal infection. To fill this knowledge gap, de novo assemblies of tobacco leaf transcriptomes were obtained in cultivars V2 and NC89 after the inoculation of either Alternaria longipes (AL) or Alternaria alternata (AA) at three different time points. We studied the gene expression profile of each cultivar-pathogen combination, and identified eight differentially expressed genes shared among all combinations. Gene ontology enrichment analysis of the differentially expressed genes revealed key components during the fungal infection, which included regulation of gene expression (GO:0010468), regulation of RNA metabolic process (GO:0051252), tetrapyrrole binding (GO:0046906), and external encapsulating structure (GO:0030312). Further analyses of the continuously upregulated/downregulated genes and the resistance genes demonstrated that the gene expression profile upon fungal infection was contingent on the specific cultivar and pathogen. In conclusion, this study provides a solid foundation for the investigation of plant-pathogen interaction, and is of great importance for disease prevention and molecular breeding. PMID:27157477

  10. Transcriptomic profile of tobacco in response to Alternaria longipes and Alternaria alternata infections.

    PubMed

    Duan, Shengchang; Ma, Xiao; Chen, Wei; Wan, Wenting; He, Yuqi; Ma, Xiaoqin; Ma, Yujin; Long, Ni; Tan, Yuntao; Wang, Yangzi; Hou, Yujie; Dong, Yang

    2016-01-01

    Tobacco brown spot caused by Alternaria fungal species is one of the most damaging diseases, and results in significant yield losses. However, little is known about the systematic response of tobacco to this fungal infection. To fill this knowledge gap, de novo assemblies of tobacco leaf transcriptomes were obtained in cultivars V2 and NC89 after the inoculation of either Alternaria longipes (AL) or Alternaria alternata (AA) at three different time points. We studied the gene expression profile of each cultivar-pathogen combination, and identified eight differentially expressed genes shared among all combinations. Gene ontology enrichment analysis of the differentially expressed genes revealed key components during the fungal infection, which included regulation of gene expression (GO:0010468), regulation of RNA metabolic process (GO:0051252), tetrapyrrole binding (GO:0046906), and external encapsulating structure (GO:0030312). Further analyses of the continuously upregulated/downregulated genes and the resistance genes demonstrated that the gene expression profile upon fungal infection was contingent on the specific cultivar and pathogen. In conclusion, this study provides a solid foundation for the investigation of plant-pathogen interaction, and is of great importance for disease prevention and molecular breeding. PMID:27157477

  11. CITRUS CANKER: PLANT PATHOLOGY VERSUS PUBLIC POLICY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing international travel and trade has resulted in an unprecedented number of plant pathogen introductions, including Xanthomonas axonopodis pv citri, (Xac), the bacterium that causes citrus canker. The disease affects commercial and dooryard citrus, and has far-reaching politi...

  12. INOCULATION STRATEGIES TO ASSESS BIOLOGICAL INTERACTIONS BETWEEN FUSARIUM AND ALTERNARIA SPECIES INFECTING SORGHUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three bioassays were assessed for experimental utility to either characterize fungal species potentially pathogenic to sorghum [Sorghum bicolor (L.) Moench] or to screen germplasm for advancement in breeding programs. Isolates of species commonly associated with sorghum, Alternaria alternata, Fusari...

  13. Potential sources of airborne Alternaria spp. spores in South-west Spain.

    PubMed

    Fernández-Rodríguez, Santiago; Sadyś, Magdalena; Smith, Matt; Tormo-Molina, Rafael; Skjøth, Carsten Ambelas; Maya-Manzano, José María; Silva-Palacios, Inmaculada; Gonzalo-Garijo, Ángela

    2015-11-15

    Fungi belonging to the genus of Alternaria are recognised as being significant plant pathogens, and Alternaria allergens are one of the most important causes of respiratory allergic diseases in Europe. This study aims to provide a detailed and original analysis of Alternaria transport dynamics in Badajoz, SW Spain. This was achieved by examining daily mean and hourly observations of airborne Alternaria spores recorded during days with high airborne concentrations of Alternaria spores (>100 s m(-3)) from 2009 to 2011, as well as four inventory maps of major Alternaria habitats, the overall synoptic weather situation and analysis of air mass transport using Hybrid Single Particle Lagrangian Integrated Trajectory model and geographic information systems. Land use calculated within a radius of 100 km from Badajoz shows that crops and grasslands are potentially the most important local sources of airborne Alternaria spores recorded at the site. The results of back trajectory analysis show that, during the examined four episodes, the two main directions where Alternaria source areas were located were: (1) SW-W; and (2) NW-NE. Regional scale and long distance transport could therefore supplement the airborne catch recorded at Badajoz with Alternaria conidia originating from sources such as crops and orchards situated in other parts of the Iberian Peninsula. PMID:26156135

  14. CHARACTERIZATION OF SPORULATION OF ALTERNARIA ALTERNATA F. SP. SPHENOCLEAE.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies were conducted on agar media to characterize the factors for the optimization of sporulation of Alternaria alternata f. sp. sphenocleae, a fungal pathogen being evaluated as a biological control agent for Sphenoclea zeylanica (gooseweed). A. alternata f. sp. sphenocleae conidiation was affec...

  15. Citrus phenylpropanoids and defence against pathogens. Part II: gene expression and metabolite accumulation in the response of fruits to Penicillium digitatum infection.

    PubMed

    Ballester, Ana-Rosa; Teresa Lafuente, M; González-Candelas, Luis

    2013-01-01

    The effect of infection of Citrus sinensis (var. Navelina) fruits with Penicillium digitatum was studied at gene expression and metabolite levels. In this study, expression of genes involved in the phenylpropanoid pathway was studied in the flavedo (outer coloured part of the peel) and albedo (inner white part) in response to pathogen infection. Results of the time-course experiment showed that maximal expression of 10 out of 17 phenylpropanoid genes analysed occurred at 48h post-inoculation, when decay symptoms started to appear, and mRNA levels either kept constant or decreased after 72h post-inoculation. To further investigate the putative involvement of the phenylpropanoid pathway in the defence of citrus fruit, changes in the metabolic profile of both tissues infected with P. digitatum was studied by means of HPLC-PDA-FD. Metabolite accumulation levels along the time course suggest that flavanones, flavones, polymethoxylated flavones and scoparone are induced in citrus fruit in response to P. digitatum infection, although with different trends depending on the tissue. PMID:23017425

  16. Clinical Characteristics of Alternaria Keratitis

    PubMed Central

    Lin, Hsin-Chiung; Chen, Phil Y. F.; Ma, David H. K.; Tan, Hsin-Yuan

    2014-01-01

    Purpose. Alternaria spp. are an uncommon cause of mycotic keratitis. Previous studies on Alternaria keratitis have generally been limited to case reports. We examined the clinical characteristics of Alternaria keratitis in this study. Methods. The characteristics and outcomes of 7 patients with culture-proven Alternaria keratitis treated in our hospital were compared with 25 previously reported cases. Results. The risk factors for Alternaria keratitis were trauma in 5 patients and soft contact lenses in 1 patient. Six patients with early diagnosis (<2 weeks) were cured with medical antimicrobial treatment; a patch graft was required in 1 patient with perforation. When incorporated with previous reports on Alternaria keratitis (n = 32), 14 (44%) infections followed trauma, 10 (31%) were associated with preexisting corneal disease or previous ocular surgery, and 5 (16%) occurred in soft contact lens wearers. Successful medical treatment was achieved in 23 (72%) patients, including 10 out of 21 eyes (48%) treated with natamycin and/or amphotericin B. Therapeutic penetrating keratoplasty was performed in 9 (28%) cases. Conclusions. Alternaria keratitis is generally associated with specific risk factors and responds to medical treatment when early diagnosis is performed and prompt antifungal treatment is initiated. PMID:24778867

  17. Pathogenicity of Penicillium digitatum is associated with the suppression of the defense-related hydrogen peroxide burst in citrus fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The high susceptibility of citrus fruit to green mold disease and lack of resistance responses suggest that P. digitatum has the ability to suppress host defenses. The current study demonstrated that during infection, P. digitatum suppresses the defense-related oxidative burst in host cells. In co...

  18. Citrus Viruses in Guatemala: Application of Laboratory-Based Assays

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In preparation for a citrus certification in Guatemala, there was an urgent need to determine which graft transmissible citrus pathogens were present. Because of the lack of biological indicator plants, Citrus tristeza virus (CTV) and Xylella fastidiosa, causal agent for citrus variegated chlorosis...

  19. A plant natriuretic peptide-like molecule of the pathogen Xanthomonas axonopodis pv. citri causes rapid changes in the proteome of its citrus host

    PubMed Central

    2010-01-01

    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. PMID:20302677

  20. Phytosanitary Status of California Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The California citrus industry continues to maintain a high phytosanitary status, albeit one with serious external threats. Propagative materials in California originate with the Citrus Clonal Protection Program, a University of California program that provides pathogen-tested, apparently clean base...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  2. Antennal and behavioral response of the Asian citrus psyllid (Diaphorina citri Kuwayama) to degradation products of citrus volatiles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae) vectors the bacterial causal pathogen of the deadly citrus disease, Huanglongbing (citrus greening) which is a major threat to citrus industry worldwide. We studied antennal and behavioral responses to principal components of head...

  3. Horsfall-Barratt recalibration and replicated severity estimates of citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker is a serious disease of citrus in tropical and subtropical citrus growing regions. Accurate and precise assessment of citrus canker and other plant pathogens is needed to obtain good quality data. Citrus canker assessment data were used to ascertain some of the mechanics of the Horsfal...

  4. Effects of simulated rainfall on disease development and weed control of the bioherbicidal fungi Alternaria cassiae and Colletotrichum truncatum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternaria cassiae and Colletotrichum truncatum are virulent pathogens of sicklepod (Senna obtusifolia), and hemp sesbania (Sesbania exaltata), respectively, under favorable environmental conditions. In greenhouse experiments, the effects of simulated rainfall on pathogenesis and mortality of these ...

  5. Hyperspectral and Thermal Imaging of Oilseed Rape (Brassica napus) Response to Fungal Species of the Genus Alternaria

    PubMed Central

    Baranowski, Piotr; Jedryczka, Malgorzata; Mazurek, Wojciech; Babula-Skowronska, Danuta; Siedliska, Anna; Kaczmarek, Joanna

    2015-01-01

    In this paper, thermal (8-13 µm) and hyperspectral imaging in visible and near infrared (VNIR) and short wavelength infrared (SWIR) ranges were used to elaborate a method of early detection of biotic stresses caused by fungal species belonging to the genus Alternaria that were host (Alternaria alternata, Alternaria brassicae, and Alternaria brassicicola) and non-host (Alternaria dauci) pathogens to oilseed rape (Brassica napus L.). The measurements of disease severity for chosen dates after inoculation were compared to temperature distributions on infected leaves and to averaged reflectance characteristics. Statistical analysis revealed that leaf temperature distributions on particular days after inoculation and respective spectral characteristics, especially in the SWIR range (1000-2500 nm), significantly differed for the leaves inoculated with A. dauci from the other species of Alternaria as well as from leaves of non-treated plants. The significant differences in leaf temperature of the studied Alternaria species were observed in various stages of infection development. The classification experiments were performed on the hyperspectral data of the leaf surfaces to distinguish days after inoculation and Alternaria species. The second-derivative transformation of the spectral data together with back-propagation neural networks (BNNs) appeared to be the best combination for classification of days after inoculation (prediction accuracy 90.5%) and Alternaria species (prediction accuracy 80.5%). PMID:25826369

  6. Quantitative Distribution of Candidatus Liberibacter asiaticus in Citrus Plants and Fruits Infected by Citrus Huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB), or greening disease, is caused by any of three non culturable Gram-negative bacteria belonging to Candidatus Liberibacter spp. The pathogens are transmitted by citrus psyllids to all commercial varieties of citrus. The diseases are lethal and have recently become widespr...

  7. Huanglongbing increases Diplodia Stem End Rot in Citrus sinensis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), one of the most devastating diseases of citrus is caused by the a-Proteobacteria Candidatus Liberibacter. Diplodia natalensis Pole-Evans is a fungal pathogen which has been known to cause a postharvest stem-end rot of citrus, the pathogen infects citrus fruit under the calyx, an...

  8. Alernaria undulata, a new species from Citrus sinensis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new species belonging to the Alternaria infectoria species-group, A undulata, is described from imported fruit of Citrus sinensis (navel Orange). A. undulata was associated with visible lesions that appeared to originate from the peduncular scars of several fruits purchased from a retail display ...

  9. Calculation of diagnostic parameters of advanced serological and molecular tissue-print methods for detection of Citrus tristeza virus. A model for other plant pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is one of the most important virus diseases which affect citrus. Control of CTV in Spain and central California is achieved by planting virus-free citrus on CTV-tolerant or -resistant rootstocks. Quarantine and certification programs remain essential to avoid importation ...

  10. Alternaria-derived serine protease activity drives IL-33–mediated asthma exacerbations

    PubMed Central

    Snelgrove, Robert J.; Gregory, Lisa G.; Peiró, Teresa; Akthar, Samia; Campbell, Gaynor A.; Walker, Simone A.; Lloyd, Clare M.

    2014-01-01

    Background The fungal allergen Alternaria alternata is implicated in severe asthma and rapid onset life-threatening exacerbations of disease. However, the mechanisms that underlie this severe pathogenicity remain unclear. Objective We sought to investigate the mechanism whereby Alternaria was capable of initiating severe, rapid onset allergic inflammation. Methods IL-33 levels were quantified in wild-type and ST2−/− mice that lacked the IL-33 receptor given inhaled house dust mite, cat dander, or Alternaria, and the effect of inhibiting allergen-specific protease activities on IL-33 levels was assessed. An exacerbation model of allergic airway disease was established whereby mice were sensitized with house dust mite before subsequently being challenged with Alternaria (with or without serine protease activity), and inflammation, remodeling, and lung function assessed 24 hours later. Results Alternaria, but not other common aeroallergens, possessed intrinsic serine protease activity that elicited the rapid release of IL-33 into the airways of mice through a mechanism that was dependent upon the activation of protease activated receptor-2 and adenosine triphosphate signaling. The unique capacity of Alternaria to drive this early IL-33 release resulted in a greater pulmonary inflammation by 24 hours after challenge relative to the common aeroallergen house dust mite. Furthermore, this Alternaria serine protease–IL-33 axis triggered a rapid, augmented inflammation, mucus release, and loss of lung function in our exacerbation model. Conclusion Alternaria-specific serine protease activity causes rapid IL-33 release, which underlies the development of a robust TH2 inflammation and exacerbation of allergic airway disease. PMID:24636086

  11. Polymorphism of the 5' terminal region of Citrus tristeza virus (CTV) RNA: incidence of three sequence types in isolates of different origin and pathogenicity.

    PubMed

    Ayllón, M A; López, C; Navas-Castillo, J; Garnsey, S M; Guerri, J; Flores, R; Moreno, P

    2001-01-01

    Sequences of the 5' terminal region of the genomic RNA from eight isolates of Citrus tristeza virus (CTV) were previously classified into three types (I, II and III), with intragroup sequence identity higher than 88% and intergroup sequence identity as low as 44%. Sequencing of an additional 58 cDNA clones from 15 virus isolates showed that all sequences could be unequivocally assigned to one of the three types previously established. The relative frequency of each sequence type was assessed in 57 CTV isolates of different geographic origin and pathogenic characteristics by RT-PCR with sets of type-specific primers using CTV dsRNA as template. None of the isolates yielded amplification of the type I or II sequences alone, but in 19 of them type III sequences were the only amplification product detected. Within isolates containing more than one sequence type, eight had type II and III sequences, 11 had type I and III sequences, and 19 had sequences of the three types. Isolates containing only type III sequences caused only mild to moderate symptoms in Mexican lime, an indicator species for most CTV isolates, whereas isolates causing stem pitting in sweet orange an/or grapefruit, generally contained sequences type II. None of the sequence types could be traced to a precise geographic area, as all types were detected in isolates from at least nine of the 12 countries from which samples were taken. PMID:11266215

  12. Citrus Genomics

    PubMed Central

    Talon, Manuel; Gmitter Jr., Fred G.

    2008-01-01

    Citrus is one of the most widespread fruit crops globally, with great economic and health value. It is among the most difficult plants to improve through traditional breeding approaches. Currently, there is risk of devastation by diseases threatening to limit production and future availability to the human population. As technologies rapidly advance in genomic science, they are quickly adapted to address the biological challenges of the citrus plant system and the world's industries. The historical developments of linkage mapping, markers and breeding, EST projects, physical mapping, an international citrus genome sequencing project, and critical functional analysis are described. Despite the challenges of working with citrus, there has been substantial progress. Citrus researchers engaged in international collaborations provide optimism about future productivity and contributions to the benefit of citrus industries worldwide and to the human population who can rely on future widespread availability of this health-promoting and aesthetically pleasing fruit crop. PMID:18509486

  13. A MLVA genotyping scheme for global surveillance of the citrus pathogen Xanthomonas citri pv. citri suggests a worldwide geographical expansion of a single genetic lineage.

    PubMed

    Pruvost, Olivier; Magne, Maxime; Boyer, Karine; Leduc, Alice; Tourterel, Christophe; Drevet, Christine; Ravigné, Virginie; Gagnevin, Lionel; Guérin, Fabien; Chiroleu, Frédéric; Koebnik, Ralf; Verdier, Valérie; Vernière, Christian

    2014-01-01

    MultiLocus Variable number of tandem repeat Analysis (MLVA) has been extensively used to examine epidemiological and evolutionary issues on monomorphic human pathogenic bacteria, but not on bacterial plant pathogens of agricultural importance albeit such tools would improve our understanding of their epidemiology, as well as of the history of epidemics on a global scale. Xanthomonas citri pv. citri is a quarantine organism in several countries and a major threat for the citrus industry worldwide. We screened the genomes of Xanthomonas citri pv. citri strain IAPAR 306 and of phylogenetically related xanthomonads for tandem repeats. From these in silico data, an optimized MLVA scheme was developed to assess the global diversity of this monomorphic bacterium. Thirty-one minisatellite loci (MLVA-31) were selected to assess the genetic structure of 129 strains representative of the worldwide pathological and genetic diversity of X. citri pv. citri. Based on Discriminant Analysis of Principal Components (DAPC), four pathotype-specific clusters were defined. DAPC cluster 1 comprised strains that were implicated in the major geographical expansion of X. citri pv. citri during the 20th century. A subset of 12 loci (MLVA-12) resolved 89% of the total diversity and matched the genetic structure revealed by MLVA-31. MLVA-12 is proposed for routine epidemiological identification of X. citri pv. citri, whereas MLVA-31 is proposed for phylogenetic and population genetics studies. MLVA-31 represents an opportunity for international X. citri pv. citri genotyping and data sharing. The MLVA-31 data generated in this study was deposited in the Xanthomonas citri genotyping database (http://www.biopred.net/MLVA/). PMID:24897119

  14. A MLVA Genotyping Scheme for Global Surveillance of the Citrus Pathogen Xanthomonas citri pv. citri Suggests a Worldwide Geographical Expansion of a Single Genetic Lineage

    PubMed Central

    Boyer, Karine; Leduc, Alice; Tourterel, Christophe; Drevet, Christine; Ravigné, Virginie; Gagnevin, Lionel; Guérin, Fabien; Chiroleu, Frédéric; Koebnik, Ralf; Verdier, Valérie; Vernière, Christian

    2014-01-01

    MultiLocus Variable number of tandem repeat Analysis (MLVA) has been extensively used to examine epidemiological and evolutionary issues on monomorphic human pathogenic bacteria, but not on bacterial plant pathogens of agricultural importance albeit such tools would improve our understanding of their epidemiology, as well as of the history of epidemics on a global scale. Xanthomonas citri pv. citri is a quarantine organism in several countries and a major threat for the citrus industry worldwide. We screened the genomes of Xanthomonas citri pv. citri strain IAPAR 306 and of phylogenetically related xanthomonads for tandem repeats. From these in silico data, an optimized MLVA scheme was developed to assess the global diversity of this monomorphic bacterium. Thirty-one minisatellite loci (MLVA-31) were selected to assess the genetic structure of 129 strains representative of the worldwide pathological and genetic diversity of X. citri pv. citri. Based on Discriminant Analysis of Principal Components (DAPC), four pathotype-specific clusters were defined. DAPC cluster 1 comprised strains that were implicated in the major geographical expansion of X. citri pv. citri during the 20th century. A subset of 12 loci (MLVA-12) resolved 89% of the total diversity and matched the genetic structure revealed by MLVA-31. MLVA-12 is proposed for routine epidemiological identification of X. citri pv. citri, whereas MLVA-31 is proposed for phylogenetic and population genetics studies. MLVA-31 represents an opportunity for international X. citri pv. citri genotyping and data sharing. The MLVA-31 data generated in this study was deposited in the Xanthomonas citri genotyping database (http://www.biopred.net/MLVA/). PMID:24897119

  15. Use of Extract of Citrus sinensis as an antimicrobial agent for foodborne zoonotic pathogens and spoilage bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foodborne pathogens remain global health problems despite concerted efforts to control the transmission of these microorganisms through food. The resurgence of drug resistant bacteria has renewed interest in developing and testing new sources of antimicrobial agents to control foodborne illness. Thi...

  16. The Pathogenicity Determinant of Citrus Tristeza Virus Causing the Seedling Yellows Syndrome is Located at the 3’-Terminal Region of the Viral Genome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) (genus Closterovirus, family Closteroviridae) causes some of the more important viral diseases of citrus worldwide. The ability to map disease-inducing determinants of CTV is needed to develop better diagnostic and disease control procedures. A distinctive phenotype of s...

  17. In vivo generated Citrus exocortis viroid progeny variants display a range of phenotypes with altered levels of replication, systemic accumulation and pathogenicity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus exocortis viroid (CEVd) exists as heterogeneous variants in plant hosts. We inoculated RNA transcripts from a CEVd cDNA clone into protoplasts, seedlings and mature plants of citrus and sequenced 240 in vivo generated progeny variants. Selected progeny variants were further used to evaluate t...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  1. Rapid screening of huanglongbing-infected citrus leaves by near infrared reflectance spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The citrus disease Haunglongbing (HLB or citrus greening), is one of the more serious diseases of citrus. An infected tree produces fruit that is unsuitable for sale as fresh fruit or for juice. The only definitive method of diagnosis of trees suspected of infection by citrus greening pathogens is...

  2. Movement of Diaphorina citri Kuwayama (Hemiptera: Liviidae) adults between huanglongbing-affected and healthy citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a vector transmitting the pathogen of citrus huanglongbing (HLB, also called yellow shoot disease or citrus greening disease). A typical symptom of citrus HLB is leaf yellowing. ACP adults behaved differently on HLB-affe...

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

    PubMed

    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. PMID:22799453

  4. The effects of citrus extract (Citrox©) on the naturally occurring microflora and inoculated pathogens, Bacillus cereus and Salmonella enterica, in a model food system and the traditional Greek yogurt-based salad Tzatziki.

    PubMed

    Tsiraki, Maria I; Savvaidis, Ioannis N

    2016-02-01

    The antimicrobial effect of citrus extract (at 1 mL/kg [TC1] and 2 mL/kg [TC2]) on the naturally occurring microflora and inoculated pathogens (Bacillus cereus and Salmonella enterica, at ca. 6 log cfu/g) in the traditional Greek yogurt-based salad Tzatziki during storage under vacuum at 4 or 10 °C was examined. We also examined the effect of citrus extract (Citrox(©)) against the two aforementioned pathogens in tryptic soy broth (TSB). Of the two treatments, TC2 yielded the lowest yeast counts, irrespective of temperature, resulting in approximately 2 (4 °C) and 3 (10 °C) log reductions on the final day of storage (70 and 30 days, respectively). Although panelists preferred the TC1-treated salad, the TC2-treated product was sensorily acceptable. Therefore, at the concentrations used, Citrox had no negative sensorial effect on the Tzatziki. During storage, the Bacillus populations in the Citrox-treated Tzatziki samples progressively decreased, showing major declines from days 12 and 28 (at 10 and 4 °C, respectively). Citrox, especially at 2 mL/kg, had a significant effect on the survival of B. cereus. S. enterica showed major declines in all untreated Tzatziki samples from day 0-70 (4 °C) and from day 0-30 (10 °C), with averages of 2.5 and 2.8 log cfu/g, respectively. The results indicate that Citrox (at 1 and 2 mL/kg) is effective, from a safety standpoint, for reducing Bacillus and Salmonella spp. in Tzatziki. In addition, 2% citrus extract also showed a higher inhibitory effect against B. cereus and S. enterica grown in TSB than 1% citrus extract. PMID:26678142

  5. Resistance to alternaria solani in hybrids between a Solanum tuberosum haploid and S. raphanifolium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early blight of potato (Solanum tuberosum L.), caused by the foliar fungal pathogen Alternaria solani is a major cause of economic loss in many potato growing regions. Genetic resistance offers an opportunity to decrease fungicide usage while maintaining yield and quality. In this study, an early bl...

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

    PubMed

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

    2016-08-01

    Citrus are among the economically most important fruit tree crops in the world. Citrus variegated chlorosis (CVC), caused by Xylella fastidiosa infection, is a serious disease limiting citrus production at a global scale. With availability of citrus genomic resources, it is now possible to compare citrus expressed sequence tag (EST) data sets and identify single-nucleotide polymorphisms (SNPs) within and among different citrus cultivars that can be exploited for citrus resistance to infections, citrus breeding, among others. We report here, for the first time, SNPs in the EST data sets of X. fastidiosa-infected Citrus sinensis (sweet orange) and their functional annotation that revealed the involvement of eight C. sinensis candidate genes in CVC pathogenesis. Among these genes were xyloglucan endotransglycosylase, myo-inositol-1-phosphate synthase, and peroxidase were found to be involved in plant cell wall metabolism. These have been further investigated by molecular modeling for their role in CVC infection and defense. Molecular docking analyses of the wild and the mutant (SNP containing) types of the selected three enzymes with their respective substrates revealed a significant decrease in the binding affinity of substrates for the mutant enzymes, thus suggesting a decrease in the catalytic efficiency of these enzymes during infection, thereby facilitating a favorable condition for infection by the pathogen. These findings offer novel agrigenomics insights in developing future molecular targets and strategies for citrus fruit cultivation in ways that are resistant to X. fastidiosa infection, and by extension, with greater harvesting efficiency and economic value. PMID:27447755

  7. Identification, characterization and mycotoxigenic ability of Alternaria spp. causing core rot of apple fruit in Greece.

    PubMed

    Ntasiou, Panagiota; Myresiotis, Charalampos; Konstantinou, Sotiris; Papadopoulou-Mourkidou, Euphemia; Karaoglanidis, George S

    2015-03-16

    Alternaria core rot is a major postharvest disease of apple fruit in several countries of the world, including Greece. The study was conducted aiming to identify the disease causal agents at species level, investigate the aggressiveness of Alternaria spp. isolates and the susceptibility of different apple varieties and determine the mycotoxigenic potential of Alternaria spp. isolates from apple fruit. Seventy-five Alternaria spp. isolates obtained from apple fruit showing core rot symptoms were identified as either Alternaria tenuissima or Alternaria arborescens at frequencies of 89.3 and 11.7%, respectively, based on the sequence of endopolygalacturonase (EndoPG) gene. Artificial inoculations of fruit of 4 different varieties (Fuji, Golden Delicious, Granny Smith and Red Delicious) and incubation at two different temperatures (2 and 25°C) showed that fruit of Fuji variety were the most susceptible and fruit of Golden Delicious the most resistant to both pathogens. In addition, the production of 3 mycotoxins, alternariol (AOH), alternariol monomethyl ether (AME) and tentoxin (TEN) was investigated in 30 isolates of both species. Mycotoxin determination was conducted both in vitro, on artificial nutrient medium and in vivo on artificially inoculated apple fruit, using a high performance liquid chromatography with diode array detector (HPLC-DAD). The results showed that most of the isolates of both species were able to produce all the 3 metabolites both in vivo and in vitro. On apple fruit A. tenuissima isolates produced more AOH than A. arborescens isolates, whereas the latter produced more TEN than the former. Such results indicate that Alternaria core rot represents a major threat of apple fruit production not only due to quantitative yield losses but also for qualitative deterioration of apple by-products. PMID:25560914

  8. Real-time PCR quantification of the AM-toxin gene and HPLC qualification of toxigenic metabolites from Alternaria species from apples.

    PubMed

    Andersen, Birgitte; Smedsgaard, Jørn; Jørring, Ida; Skouboe, Pernille; Pedersen, Lars Hagsholm

    2006-09-01

    Some Alternaria species are able to produce plant pathogenic as well as toxic metabolites. In both agriculture and the food industry it is important know if toxigenic Alternaria are present to rapidly employ the correct corrective actions. The purpose of this work was to establish a real-time PCR method, which can detect and quantify apple pathogenic and toxigenic Alternaria. An AM-toxin I primer set, which could recognize Alternaria DNA only, was designed by using primers complementary to the AM-toxin I gene. The method could detect small amounts of DNA (4 pg) and still obtain a large dynamic range (4 decades) without interference from apple material. Eight Alternaria isolates were analyzed for the presence of AM-toxin I gene and their production of secondary metabolites. Then analyses showed that all eight isolates contained the AM toxin gene and were able to produce the plant pathogenic tentoxin in addition to AM toxin I. The analyses also showed the production of tenuazonic acid, alternariols, Altenuene, altenusin and/or altertoxin I in pure culture. Analyses of inoculated apples showed that both the AM-toxin gene and alternariol monomethyl ether could be detected. Morphological analyses suggested that the eight Alternaria strains, though they all carried the AM toxin genes, probably belong to different but closely related un-described Alternaria taxa in the A. tenuissima species-group based on morphological and chemical differences. PMID:16890318

  9. Citrus huanglongbing shapes the structure of bacterial community associated with citrus roots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To examine the effect of pathogen on the diversity and structure of plant associated bacterial community, we carried out a molecular based analysis using citrus and huanglongbing as host-disease model. 16S rDNA clone library analysis of the citrus roots revealed shifts in the microbial diversity in ...

  10. How the Necrotrophic Fungus Alternaria brassicicola Kills Plant Cells Remains an Enigma

    PubMed Central

    2015-01-01

    Alternaria species are mainly saprophytic fungi, but some are plant pathogens. Seven pathotypes of Alternaria alternata use secondary metabolites of host-specific toxins as pathogenicity factors. These toxins kill host cells prior to colonization. Genes associated with toxin synthesis reside on conditionally dispensable chromosomes, supporting the notion that pathogenicity might have been acquired several times by A. alternata. Alternaria brassicicola, however, seems to employ a different mechanism. Evidence on the use of host-specific toxins as pathogenicity factors remains tenuous, even after a diligent search aided by full-genome sequencing and efficient reverse-genetics approaches. Similarly, no individual genes encoding lipases or cell wall-degrading enzymes have been identified as strong virulence factors, although these enzymes have been considered important for fungal pathogenesis. This review describes our current understanding of toxins, lipases, and cell wall-degrading enzymes and their roles in the pathogenesis of A. brassicicola compared to those of other pathogenic fungi. It also describes a set of genes that affect pathogenesis in A. brassicicola. They are involved in various cellular functions that are likely important in most organisms and probably indirectly associated with pathogenesis. Deletion or disruption of these genes results in weakly virulent strains that appear to be sensitive to the defense mechanisms of host plants. Finally, this review discusses the implications of a recent discovery of three important transcription factors associated with pathogenesis and the putative downstream genes that they regulate. PMID:25681268

  11. Citrus Inventory

    NASA Technical Reports Server (NTRS)

    1994-01-01

    An aerial color infrared (CIR) mapping system developed by Kennedy Space Center enables Florida's Charlotte County to accurately appraise its citrus groves while reducing appraisal costs. The technology was further advanced by development of a dual video system making it possible to simultaneously view images of the same area and detect changes. An image analysis system automatically surveys and photo interprets grove images as well as automatically counts trees and reports totals. The system, which saves both time and money, has potential beyond citrus grove valuation.

  12. Citrus Inventory

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Florida's Charlotte County Property Appraiser is using an aerial color infrared mapping system for inventorying citrus trees for valuation purposes. The ACIR system has significantly reduced the time and manpower required for appraisal. Aerial photographs are taken and interpreted by a video system which makes it possible to detect changes from previous years. Potential problems can be identified. KSC's TU Office has awarded a contract to the Citrus Research and Education Center to adapt a prototype system which would automatically count trees and report totals.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri Kuwayama, the Asian citrus psyllid (ACP), is a devastating citrus pest due to its transmission of a phloem-limited bacterial pathogen, Candidatus Liberibacter asiaticus, that causes citrus greening. Psyllid control is a major part of effective greening disease management, and our r...

  14. 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.

    PubMed

    Al-Saadi, Abdulwahid; Reddy, Joseph D; Duan, Yong P; Brunings, Asha M; Yuan, Qiaoping; Gabriel, Dean W

    2007-08-01

    Citrus canker disease is caused by five groups of Xanthomonas citri strains that are distinguished primarily by host range: three from Asia (A, A*, and A(w)) and two that form a phylogenetically distinct clade and originated in South America (B and C). Every X. citri strain carries multiple DNA fragments that hybridize with pthA, which is essential for the pathogenicity of wide-host-range X. citri group A strain 3213. DNA fragments that hybridized with pthA were cloned from a representative strain from all five groups. Each strain carried one and only one pthA homolog that functionally complemented a knockout mutation of pthA in 3213. Every complementing homolog was of identical size to pthA and carried 17.5 nearly identical, direct tandem repeats, including three new genes from narrow-host-range groups C (pthC), A(w) (pthAW), and A* (pthA*). Every noncomplementing paralog was of a different size; one of these was sequenced from group A* (pthA*-2) and was found to have an intact promoter and full-length reading frame but with 15.5 repeats. None of the complementing homologs nor any of the noncomplementing paralogs conferred avirulence to 3213 on grapefruit or suppressed avirulence of a group A* strain on grapefruit. A knockout mutation of pthC in a group C strain resulted in loss of pathogenicity on lime, but the strain was unaffected in ability to elicit an HR on grapefruit. This pthC- mutant was fully complemented by pthA, pthB, or pthC. Analysis of the predicted amino-acid sequences of all functional pthA homologs and nonfunctional paralogs indicated that the specific sequence of the 17th repeat may be essential for pathogenicity of X. citri on citrus. PMID:17722697

  15. Alternaria keratitis after deep anterior lamellar keratoplasty.

    PubMed

    Naik, Mekhla; Mohd Shahbaaz; Sheth, Jay; Sunderamoorthy, S K

    2014-01-01

    To describe a case of Alternaria keratitis in a 30-year-old male patient who presented with bilateral vascularised central corneal opacity and underwent deep anterior lamellar keratoplasty (DALK) in the left eye. Patient was treated for recurrent epithelial defect with a bandage contact lens in the follow-up visits after DALK. Subsequently, patient presented with pigmented fungal keratitis, which on culture examination of the corneal scrapping demonstrated Alternaria species. Patient had to undergo a repeat DALK as the keratitis did not resolve with medical therapy alone. Patient did not have a recurrence for 11 months following the regraft. This case report highlights the importance of considering the Alternaria species as a possibile cause of non-resolving fungal keratitis after DALK. PMID:24669155

  16. First Report of Black Spot Disease Caused by Alternaria alternata on Sweet Persimmon Fruits

    PubMed Central

    Lee, Jung Han; Kim, Jinwoo

    2013-01-01

    Black spot of sweet persimmon, caused by Alternaria alternata, occurred in an orchard in Gyeongnam province, Korea in 2012. The symptom was appearance of 0.5 to 4 cm black spots on the surface of fruit. The pathogen was isolated from flesh of disease lesions. The causal agent was identified as A. alternata by morphological characteristics and sequencers of the internal transcribed spacer (ITS) 1 and ITS4 regions of rRNA. Artificial inoculation of the pathogen resulted in development of disease symptoms and the re-isolated pathogen showed characteristics of A. alternata. PMID:24198674

  17. Nonhost-specific phytotoxicity of the polyketide-derived toxin solanapyrone A produced by Ascochyta rabiei and Alternaria solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Solanapyrone A is a polyketide-derived metabolite produced by Ascochyta rabiei and Alternaria solani, which are the most destructive necrotrophic pathogens of chickpea and potato/tomato, respectively. They belong to the Order Pleosporales within the Class Dothideomycetes, but are phylogenetically di...

  18. First Report of a Leaf Spot Caused by Alternaria brassicae on the Invasive Weed Lepidium draba in North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A second leaf spot disease on the perennial invasive weed white top, aka hoary cress, was found in a stand of white top in south central Montana. The plant pathogen causing the lesions was identified as the fungus Alternaria brassicae. It was isolated, purified grown on a V-8 agar growth medium and ...

  19. Optimal strategies for the eradication of Asiatic citrus canker in heterogeneous host landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The eradication of non-native plant pathogens is a key challenge in plant disease epidemiology. Asiatic citrus canker is an economically significant disease of citrus caused by the bacterial plant pathogen Xanthomonas citri subsp. citri. The pathogen is a major exotic disease problem in many citru...

  20. Experiments with Biocontrol of Alternaria alternata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A biocontrol yeast (WRL-76) developed by USDA-ARS at the Western Regional Research lab was evaluated for control of Alternaria alternata on pistachio. The experiment was conducted over a four year period in a Madera Co., CA orchard. Counts of damaged vs. intact fruit clusters were taken on 100 contr...

  1. Wind speed and wind-associated leaf injury affect severity of citrus canker on Swingle citrumelo

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (caused by the bacterial pathogen Xanthomonas citri subsp. citri, Xcc) can cause severe damage to citrus. It is endemic in Florida, and occurs in other citrus growing regions. The bacterium is dispersed predominantly in rain splash. To simulate dispersal in splash, and to investigate t...

  2. Investigations of the feasibility for managing the Asian citrus pysllid using Isaria fumosorosea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (AsCP), Diaphorina citri, transmits one of the most devastating diseases of citrus, the plant pathogenic bacterium Candidatus Liberibacter asiaticus, which is strongly associated with the occurrence of huanglongbing (HLB), also known as citrus greening disease. In Florida, g...

  3. Dramatic Change in Citrus tristeza virus populations in the Dominican Republic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is the most destructive viral pathogen of citrus and has been an important concern for the citrus industry in the Dominican Republic. Earlier studies documented widespread distribution of mild isolates of the T30 genotype, which caused no disease in the infected trees, an...

  4. Deep sequencing of citrus affected by graft-transmissible diseases of unknown etiology leads to discovery of two novel viruses.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus is susceptible to graft-transmissible disease agents and to a number of arthropod-transmitted pathogens. Citrus cultivars vary greatly in susceptibility or tolerance to these pathogens. Furthermore, pathogenicity amongst pathogen strains also varies. Established tests for known disease agent...

  5. Mycotoxin production in liquid culture and on plants infected with Alternaria spp. isolated from rocket and cabbage.

    PubMed

    Siciliano, Ilenia; Ortu, Giuseppe; Gilardi, Giovanna; Gullino, Maria Lodovica; Garibaldi, Angelo

    2015-03-01

    Fungi belonging to the genus Alternaria are common pathogens of fruit and vegetables with some species able to produce secondary metabolites dangerous to human health. Twenty-eight Alternaria isolates from rocket and cabbage were investigated for their mycotoxin production. Five different Alternaria toxins were extracted from synthetic liquid media and from plant material (cabbage, cultivated rocket, cauliflower). A modified Czapek-Dox medium was used for the in vitro assay. Under these conditions, more than 80% of the isolates showed the ability to produce at least one mycotoxin, generally with higher levels for tenuazonic acid. However, the same isolates analyzed in vivo seemed to lose their ability to produce tenuazonic acid. For the other mycotoxins; alternariol, alternariol monomethyl ether, altenuene and tentoxin a good correlation between in vitro and in vivo production was observed. In vitro assay is a useful tool to predict the possible mycotoxin contamination under field and greenhouse conditions. PMID:25751147

  6. Molecular diversity of Citrus tristeza virus in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is a serious citrus pathogen worldwide. Recent genetic studies have identified five standard CTV genotypic groups: T30, VT, T36, T3, and B165/T68. Field surveys performed in California in 2008-2010 identified primarily MCA13-negative CTV isolates with T30-like genotype. C...

  7. Detection of fluorescent compounds in citrus leaf cankers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker caused by the pathogenic bacterium, Xanthomonas citri subsp. citri (Xcc), poses a serious threat to citrus production in Florida, especially for the fresh fruit market. Xcc causes severe damage to fruit, stem, and leaf tissues, and although much has been learned about the complex inter...

  8. Behavioral plasticity in Diaphorina citri feeding on different citrus tissues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian Citrus Psyllid (Diaphorina citri) is a vector of Candidatus Liberibacter asiaticus (CLas), a phloem-limited bacterial pathogen of citrus. While psyllid nymphs are obligate feeders on young flush leaves, adults can be found on leaves of any age. To understand risk of transmission of CLas, i...

  9. Citrus leprosis research update

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  10. Citrus blight research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With HLB now occurring throughout Florida citrus groves, citrus blight has been getting less attention even though the problem still exists. In fact, the combination of HLB and citrus blight has compounded the problem that the citrus industry is facing with decreased yields, small fruit size and tre...

  11. Metabolic Interplay between the Asian citrus psyllid and its Profftella symbiont: An Achilles’ heel of the citrus greening insect vector

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Candidatus Liberibacter asiaticus’ (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid. Interactions among D. citri and its microbial endosymbionts, including ‘Candidatus Profftella armatura’, are likely to impact tra...

  12. Innate and Conditioned Responses to Chemosensory and Visual Cues in Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae), Vector of Huanglongbing Pathogens.

    PubMed

    Patt, Joseph M; Stockton, Dara; Meikle, William G; Sétamou, Mamoudou; Mafra-Neto, Agenor; Adamczyk, John J

    2014-01-01

    Asian citrus psyllid (Diaphorina citri) transmits Huanglongbing, a devastating disease that threatens citrus trees worldwide. A better understanding of the psyllid's host-plant selection process may lead to the development of more efficient means of monitoring it and predicting its movements. Since behavioral adaptations, such as associative learning, may facilitate recognition of suitable host-plants, we examined whether adult D. citri could be conditioned to visual and chemosensory stimuli from host and non-host-plant sources. Response was measured as the frequency of salivary sheaths, the residue of psyllid probing activity, in a line of emulsified wax on the surface of a test arena. The psyllids displayed both appetitive and aversive conditioning to two different chemosensory stimuli. They could also be conditioned to recognize a blue-colored probing substrate and their response to neutral visual cues was enhanced by chemosensory stimuli. Conditioned psyllids were sensitive to the proportion of chemosensory components present in binary mixtures. Naïve psyllids displayed strong to moderate innate biases to several of the test compounds. While innate responses are probably the psyllid's primary behavioral mechanism for selecting host-plants, conditioning may enhance its ability to select host-plants during seasonal transitions and dispersal. PMID:26462949

  13. Innate and Conditioned Responses to Chemosensory and Visual Cues in Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae), Vector of Huanglongbing Pathogens

    PubMed Central

    Patt, Joseph M.; Stockton, Dara; Meikle, William G.; Sétamou, Mamoudou; Mafra-Neto, Agenor; Adamczyk, John J.

    2014-01-01

    Asian citrus psyllid (Diaphorina citri) transmits Huanglongbing, a devastating disease that threatens citrus trees worldwide. A better understanding of the psyllid’s host-plant selection process may lead to the development of more efficient means of monitoring it and predicting its movements. Since behavioral adaptations, such as associative learning, may facilitate recognition of suitable host-plants, we examined whether adult D. citri could be conditioned to visual and chemosensory stimuli from host and non-host-plant sources. Response was measured as the frequency of salivary sheaths, the residue of psyllid probing activity, in a line of emulsified wax on the surface of a test arena. The psyllids displayed both appetitive and aversive conditioning to two different chemosensory stimuli. They could also be conditioned to recognize a blue-colored probing substrate and their response to neutral visual cues was enhanced by chemosensory stimuli. Conditioned psyllids were sensitive to the proportion of chemosensory components present in binary mixtures. Naïve psyllids displayed strong to moderate innate biases to several of the test compounds. While innate responses are probably the psyllid’s primary behavioral mechanism for selecting host-plants, conditioning may enhance its ability to select host-plants during seasonal transitions and dispersal. PMID:26462949

  14. Detection and characterization of a novel reovirus in the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We successfully used a genomics approach to discover viral pathogens in the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae). These psyllids are vectors of the devastating disease, Huanglongbing, now affecting citrus in the USA, and world wide. Discovery of viral pathogens of psyllids m...

  15. DIFFERENTIAL EFFECTS OF CITRUS PEEL EXTRACTS ON GROWTH OF PENICILLIUM DIGITATIUM, P. ITALICUM AND P. EXPANSUM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most pathogenic species of Penicillium have a limited host range, suggesting unique adaptations to particular hosts. P. digitatum and P. italicum are primarily pathogens of mature citrus fruit, while P. expansum has a broad host range, but does not infect citrus. One possible basis of host specifi...

  16. Volatile Organic Compound (VOC) profiling of Citrus tristeza virus (CTV) infection in sweet orange citrus varietals using thermal desorption gas chromatography time of flight mass spectrometry (TD-GC/TOF-MS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is a plant pathogen which predominately infects economically important citrus crops such as sweet orange, clementine, lime and grapefruit varietals. Within the last 70 years, an estimated 100 million citrus trees on sour orange rootstock have been destroyed due to CTV inf...

  17. Visual rating and the use of image analysis for assessing different symptoms of citrus canker on grapefruit leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker is caused by the bacterial pathogen Xanthomonas axonopodis pv citri (Xac) and infects several citrus species in wet tropical and subtropical citrus growing regions. Accurate, precise and reproducible disease assessment is needed for monitoring epidemics and disease response in breeding...

  18. NPDN Citrus Greening Diagnostic and Detection Efforts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Plant Diagnostic Network (NPDN) has been involved in detection and diagnosis of many new plant diseases, including citrus greening, huanglongbing (HLB), caused by a fastidious bacterium, Candidatus Liberibacter asiaticus. The pathogen is on the USDA List of Select Agents, which indicat...

  19. Asian citrus psyllid genome (Diaphorina citri, Hemiptera)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Psyllid genome is a scientific breakthrough in that it opens the psyllid genetic blueprint to investigations of all questions ranging from taxonomic origins to the understanding of developmental biology, to the acquisition and transmission of pathogens. The Asian citrus psyllid, Diaphorina citri...

  20. Characterization of the Asian citrus psyllid transcriptome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (Diaphorina citri Kuwayama) and other psyllids are important agricultural pests that cause extensive economic damage by feeding and as vectors of plant pathogens. No psyllid genomes have been characterized, and little is known about the composition of psyllid genomes or the ...

  1. PCR and real-time PCR assays to detect fungi of Alternaria alternata species.

    PubMed

    Kordalewska, Milena; Brillowska-Dąbrowska, Anna; Jagielski, Tomasz; Dworecka-Kaszak, Bożena

    2015-01-01

    Fungi of the Alternaria genus are mostly associated with allergic diseases. However, with a growing number of immunocompromised patients, these fungi, with A. alternata being the most prevalent one, are increasingly recognized as etiological agents of infections (phaeohyphomycoses) in humans. Nowadays, identification of Alternaria spp. requires their pure culture and is solely based on morphological criteria. Clinically, Alternaria infections may be indistinguishable from other fungal diseases. Therefore, a diagnostic result is often delayed or even not achieved at all. In this paper we present easy to perform and interpret PCR and real-time PCR assays enabling detection of A. alternata species. On the basis of alignment of β-tubulin gene sequences, A. alternata-specific primers were designed. DNA from fungal isolates, extracted in a two-step procedure, were used in PCR and real-time PCR assays followed by electrophoresis or melting temperature analysis, respectively. The assays specificity was confirmed, since positive results were obtained for all A. alternata isolates, and no positive results were obtained neither for other molds, dermatophytes, yeast-like fungi, nor human DNA. The assays developed here enable fast and unambiguous identification of A. alternata pathogens. PMID:26610309

  2. Presence of adhesive vesicles in the mycoherbicide Alternaria helianthi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternaria helianthi conidia have been shown to cause disease on common cocklebur. Conidia were applied to slides made hydrophobic by coating with dimethyldicholorosilane (mimics leaf surface), then rinsed and treated with FITC-Con A to stain the adhesive material. Alternaria helianthi coni...

  3. Effect of citrus pulp on the viability of the probiotic Saccharomyces cerevisiae bouldarii (Levucell) and subsequent effects in presence of pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The probiotic Saccharomyces cerevisiae subtype boulardii (i.e., Levucell) is commonly provided to weaned and nursing sows to promote intestinal health through limiting the colonization of pathogens. Recent research from our group identified that supplementation of this probiotic to feed containing t...

  4. Immunotherapy with Alternaria alternata: present and future.

    PubMed

    Martínez-Cañavate Burgos, A; Valenzuela-Soria, A; Rojo-Hernández, A

    2007-01-01

    The prevalence of fungal allergies is greater than previously believed; consequently, such processes have been underestimated as potential causes of respiratory tract disease. Most patients sensitized to fungi exhibit perennial symptoms, though their intensity increases in the summer and autumn months. Skin reactions to the antigens of Alternaria alternata are associated with a high risk of allergic respiratory conditions in the presence of spores of this fungus -fundamentally in children and young adults- with a special form of presentation as life-threatening asthma. Very few controlled studies have examined the efficacy and safety of fungal extract immunotherapy -the main problem being the lack of standardized extracts for the diagnosis and treatment of such patients. In the year 2005 a tolerance study was made in children in relation to a depot extract containing the predominant antigen of Alternaria, with two different regimens (short and cluster). Tolerance was found to be good, with a 0.95 % incidence of local reactions and a 0.95 % incidence of grade 2 systemic reactions. Few studies involving sublingual immunotherapy have been conducted to date. PMID:18047818

  5. Proteomic analysis of Alternaria alternata (Fr.) Keissler responds to COS fumigation.

    PubMed

    Liu, Tao; Li, Li; Qu, Haixia; Zhan, Guoping; Liu, Bo; Wang, Yuejin

    2010-01-01

    Carbonyl sulfide (COS) is a new fumigant which has been a potential alternative to methyl bromide and phosphine in many applications. In this study, we investigated the fungitoxicity of COS towards the pathogen of pear black spot disease Alternaria alternata (Fr.) Keissler (A. alternata). Moreover, proteomic analysis and RT-PCR was performed and our results showed that during the fumigation, the regulation of 21 proteins in protein expression and mRNA accumulation levels is involved, which respond to growth inhibition caused by COS. These results provide new clues for the mechanism of the fungitoxicity of COS. PMID:20036892

  6. Evaluation of Alternaria mycotoxins in strawberries: quantification and storage condition.

    PubMed

    Juan, Cristina; Oueslati, Souheib; Mañes, Jordi

    2016-05-01

    Alternariol (AOH), alternariol methyl ether (AME) and tentoxin (TEN) are Alternaria mycotoxins produced by the most common post-harvest pathogens of fruits. The production of these metabolites depends on several environmental factors, mainly temperature, water activity, pH and the technological treatments that have been applied to the product. In this study, the occurrence of AOH, AME and TEN was evaluated in strawberries samples stored at different temperatures ranges (at 22 ± 2 or 6 ± 2°C) and different periods (up to 1 month) simulating the current practice of consumer's storage conditions. Sample extraction was performed using a liquid-liquid extraction method prior to LC-MS/MS analysis. AOH was the most prevalent mycotoxins with a 42% at strawberries stored at (22 ± 2)°C and 37% stored at (6 ± 2)°C. The highest AOH levels were found in samples conserved at (22 ± 2)°C ranging between 26 and 752 ng g(-1). AME levels ranged between 11 and 137 ng g(-)(1), which were found mainly in stored samples at (6 ± 2)°C for more than 28 days. None sample presented levels of TEN in either of the studied conditions. PMID:27103180

  7. CmWRKY15 Facilitates Alternaria tenuissima Infection of Chrysanthemum.

    PubMed

    Fan, Qingqing; Song, Aiping; Xin, Jingjing; Chen, Sumei; Jiang, Jiafu; Wang, Yinjie; Li, Xiran; Chen, Fadi

    2015-01-01

    Abscisic acid (ABA) has an important role in the responses of plants to pathogens due to its ability to induce stomatal closure and interact with salicylic acid (SA) and jasmonic acid (JA). WRKY transcription factors serve as antagonistic or synergistic regulators in the response of plants to a variety of pathogens. Here, we demonstrated that CmWRKY15, a group IIa WRKY family member, was not transcriptionally activated in yeast cells. Subcellular localization experiments in which onion epidermal cells were transiently transfected with CmWRKY15 indicated that CmWRKY15 localized to the nucleus in vivo. The expression of CmWRKY15 could be markedly induced by the presence of Alternaria tenuissima inoculum in chrysanthemum. Furthermore, the disease severity index (DSI) data of CmWRKY15-overexpressing plants indicated that CmWRKY15 overexpression enhanced the susceptibility of chrysanthemum to A. tenuissima infection compared to controls. To illustrate the mechanisms by which CmWRKY15 regulates the response to A. tenuissima inoculation, the expression levels of ABA-responsive and ABA signaling genes, such as ABF4, ABI4, ABI5, MYB2, RAB18, DREB1A, DREB2A, PYL2, PP2C, RCAR1, SnRK2.2, SnRK2.3, NCED3A, NCED3B, GTG1, AKT1, AKT2, KAT1, KAT2, and KC1were compared between transgenic plants and controls. In summary, our data suggest that CmWRKY15 might facilitate A. tenuissima infection by antagonistically regulating the expression of ABA-responsive genes and genes involved in ABA signaling, either directly or indirectly. PMID:26600125

  8. CmWRKY15 Facilitates Alternaria tenuissima Infection of Chrysanthemum

    PubMed Central

    Fan, Qingqing; Song, Aiping; Xin, Jingjing; Chen, Sumei; Jiang, Jiafu; Wang, Yinjie; Li, Xiran; Chen, Fadi

    2015-01-01

    Abscisic acid (ABA) has an important role in the responses of plants to pathogens due to its ability to induce stomatal closure and interact with salicylic acid (SA) and jasmonic acid (JA). WRKY transcription factors serve as antagonistic or synergistic regulators in the response of plants to a variety of pathogens. Here, we demonstrated that CmWRKY15, a group IIa WRKY family member, was not transcriptionally activated in yeast cells. Subcellular localization experiments in which onion epidermal cells were transiently transfected with CmWRKY15 indicated that CmWRKY15 localized to the nucleus in vivo. The expression of CmWRKY15 could be markedly induced by the presence of Alternaria tenuissima inoculum in chrysanthemum. Furthermore, the disease severity index (DSI) data of CmWRKY15-overexpressing plants indicated that CmWRKY15 overexpression enhanced the susceptibility of chrysanthemum to A. tenuissima infection compared to controls. To illustrate the mechanisms by which CmWRKY15 regulates the response to A. tenuissima inoculation, the expression levels of ABA-responsive and ABA signaling genes, such as ABF4, ABI4, ABI5, MYB2, RAB18, DREB1A, DREB2A, PYL2, PP2C, RCAR1, SnRK2.2, SnRK2.3, NCED3A, NCED3B, GTG1, AKT1, AKT2, KAT1, KAT2, and KC1were compared between transgenic plants and controls. In summary, our data suggest that CmWRKY15 might facilitate A. tenuissima infection by antagonistically regulating the expression of ABA-responsive genes and genes involved in ABA signaling, either directly or indirectly. PMID:26600125

  9. Development of consumer-friendly transgenic citrus plants with potential broad spectrum resistance to HLB, Citrus canker, Phytopthora and other exotic diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The second year of this CRB funded project has started, which is focused on the development of citrus cultivars that exhibit disease resistance to multiple pathogens such as HLB, Phytophthora and citrus canker diseases. We are using precise genetic engineering to introduce into disease susceptible ...

  10. Processes involved in the dispersal of Xanthomonas citri pv. citri from canker-infectd citrus canopies, and in the infection of citrus foliage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) is now considered endemic in Florida, and epidemics result in yield loss and market penalties both in Florida, and elsewhere where the pathogen occurs, and susceptible citrus is cultivated. The bacterium is dispersed in rain splash, and storms wit...

  11. Processess involved in the dispersal of Xanthomonas citri pv. citri from canker-infected citrus canopies, and in the infection of citrus foliage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) is now considered endemic in Florida, and epidemics result in yield loss and market penalties both in Florida and elsewhere, where the pathogen occurs and susceptible citrus is cultivated. The bacterium is dispersed in rain splash, and storms with...

  12. Ontogenic variation in citrus flush shoots and its relation with host plant finding and acceptance by Asian citrus psyllid (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae) is a destructive insect mainly because it vectors the bacterial pathogens that cause the deadly and incurable citrus greening disease. Diaphorina citri adult females lay eggs and immature development occurs exclusively on new flush sh...

  13. GENE EXPRESSION IN THE ASIAN CITRUS PSYLLID: VECTOR OF CITRUS GREENING (HEMIPTERA: PSYLLIDAE)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Production of a unigene set identified the putative functions of over 500 transcripts from the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). D. citri is the primary vector of Huanglongbing, HLB, which is a severe plant pathogenic bacterium that causes severe economic losses...

  14. In vitro and in vivo activity of essential oils against major postharvest pathogens of Kinnow (Citrus nobilis × C. deliciosa) mandarin.

    PubMed

    Jhalegar, Md Jameel; Sharma, R R; Singh, Dinesh

    2015-04-01

    The present study envisages the influence of essential oils namely lemon grass, eucalyptus, clove and neem on Kinnow mandarin with the objective to combat major post harvest diseases and to prolong its availability for longer time in the season. For this, in vitro and in vivo studies were conducted. Poisoned food technique was used for in vitro studies, and for in vivo studies, Kinnow fruit were pre-inoculated with pathogens (Penicillium digitatum and P. italicum), treated with different essential oils and then stored at 5 °C ±1 °C temperature and 85-90 % RH). Our results indicated that all essential oils inhibited the growth (colony diameter) of both pathogens over untreated PDA plates, but the inhibition was the strongest by lemon grass oil. Similarly, under in vivo conditions, all essential oils influenced decay incidence, decay loss, lesion diameter, respiration rate, ethylene evolution, overall acceptability and physiological loss in weight but lemon grass was the most effective. And also the incidence of Penicillium italicum was more noticed in fruits than P. digitatum, however, it was reverse under in vitro conditions. The decay rot at all stages of storage was less in EOs treated fruits than untreated fruits, thereby increasing their storage life significantly. Thus, it is evident from our studies that essential oils have the potential to control green and blue mold without causing any injury or harmful effects on Kinnow mandarin, and EOs can be recommended as a safe method for extending its storage life while maintaining fruit quality. PMID:25829604

  15. Citrus Waste Biomass Program

    SciTech Connect

    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.

  16. Molecular diversity of Citrus tristeza virus (CTV) strains collected over the past 50 years and maintained in CTV collections in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tristeza, caused by Citrus tristeza virus (CTV), is a serious citrus disease worldwide. Because severe strains of CTV reduce fruit production and quality, CTV has been eliminated from citrus germplasm sources by a certification program. CTV is also a regulated pathogen in quarantine zones and infec...

  17. High incidence of preharvest colonization of huanglongbing-symptomatic Citrus sinensis fruit by Lasiodiplodia theobromae (Diplodia natalensis) and exacerbation of postharvest fruit decay by that fungus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), presumably caused by bacterium Candidatus Liberibacter asiaticus (CLas), is a devastating citrus disease associated with excessive pre-harvest fruit drop. Lasiodiplodia theobromae (Diplodia) is the causal organism of citrus stem end rot (SER). The pathogen infects citrus fruit ...

  18. New Perspectives on the Epidemiology of Citrus Stubborn Disease in California Orchards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although citrus stubborn disease (CSD), caused by the phloem resident mollicute Spiroplasma citri, is a significant threat to California citrus industry, our knowledge of its epidemiology is mostly anecdotal. We optimized multiple pathogen-detection protocols, measured disease incidence in two plots...

  19. A phagostimulant blend for T1 the Asian citrus psyllid (Hemiptera: Liviidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chemical cues that condition orientation by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), are of great interest because it is the primary vector of the causal pathogen of citrus greening disease. Previous work in our lab identified a blend of formic and acetic acids as s...

  20. Rapid screening for citrus canker resistance employing pattern-triggered immunity (PTI) responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker, caused by the bacterial pathogen Xanthomonas citri ssp. citri (Xcc), has been attributed to millions of dollars in loss or damage to commercial citrus crops in subtropical production areas of the world. Since identification of resistant plants is one of the most effective methods of d...

  1. Evaluation of low-volume sprayers used in asian citrus Psyllid control applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (Diaphorina citri Kumayama, Sternorrhyncha: Psyllidae) is a detrimental pest to citrus crops when it serves as a vector of the pathogen that causes greening (huanglongbing, or HLB). Transmission of this disease causes mottling, chlorosis, dieback and reductions in both frui...

  2. An Inexpensive and Safe Experiment to Demonstrate Koch's Postulates Using Citrus Fruit

    ERIC Educational Resources Information Center

    Jakobi, Steven

    2010-01-01

    Citrus fruit (oranges, tangerines, grapefruit or lemons) purchased in a grocery store can be experimentally infected with readily-available sources of "Penicillium digitatum" to demonstrate the four basic steps of Koch's postulates, also known as proof of pathogenicity. The mould is isolated from naturally-infected citrus fruit into pure culture…

  3. Genetic diversity and evidence for recent modular recombination in Hawaiian Citrus tristeza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Hawaiian Islands are home to a widespread and diverse population of Citrus tristeza virus (CTV), an economically important pathogen of citrus. In this study we quantified the genetic diversity of two CTV genes and determined the complete genomic sequence for two strains of Hawaiian CTV. The nucl...

  4. Molecular Detection of Spiroplasma Citri Associated with Stubborn Disease in Citrus Orchards in Syria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spiroplasma citri, a phloem-limited pathogen, causes citrus stubborn disease (CSD) and can be transmitted from plant to plant by several species of phloem-feeding leafhoppers. CSD is an important disorder in certain warm and arid citrus-growing areas, and its agent has been recorded from several Med...

  5. Estimation of incidence and spatial temporal distribution of Citrus Stubborn disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus stubborn disease (CSD) is caused by Spiroplasma citri, a culturable wall-less prokaryote. The pathogen is graft-transmissible and vectored by the beet leafhopper (BLH). The objective of this study was to determine incidence and spread of S. citri in two sweet orange citrus groves in the San J...

  6. Molecular Characterization of Citrus Tristeza Virus Isolates from Mild Strain Cross Protection Experiments in Peru

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seven isolates of Citrus tristeza virus (CTV) collected from the Topara Nursery, Lima, Peru were established as in planta cultures in Madam Vinous sweet orange in the Exotic Citrus Pathogen Quarantine Greenhouse, Beltsville, MD. Two of the isolates were collected from non-cross protected plants; Pe...

  7. Antifeedant and lethal effects of the fungi Isaria fumosorosea on the Asian citrus psyllid Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An insect-infecting fungal pathogen increases mortality of Asian citrus psyllids (Diaphorina citri,Hemiptera:Psyllidae). The entomopathogenic fungi(Isaria fumosorosea [Ifr])sold as the product PFR 97™ was shown to be effective at killing and reducing feeding of the Asian citrus psyllid. The psyllid ...

  8. Cercosporoid diseases of Citrus.

    PubMed

    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. PMID:26432805

  9. Certification Programs for Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    PubMed

    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

  11. [Research of chemotaxis response of Botrytis cinerea and Alternaria panax on total ginsenosides].

    PubMed

    Chi, Kun; Xu, Yong-hua; Lei, Feng-jie; Yin, Min-jing; Wang, Zhuang; Zhang, Ai-hua; Zhang, Lian-xue

    2015-10-01

    In this paper, three kinds of chemotactic parameters (concentration, temperature and pH) were determined by plate assay and spore germination method to research the chemotactic response of Botrytis cinerea and Alternaria panax, and their spores on total ginsenosides. The results showed that Botrytis cinerea had strong chemotactic response at the mid-concentration of total ginsenosides (cultivation temperature was 20 degrees C and pH value was 6), and the data of chemotactic migration index (CMI) was 1.293 0, chemotactic growth rate (CGR) was 0.476 0, spore germination rate (SGR) was 53%, and dry weight of mycelial (DWM) was 0.452 6 g x L(-1); however, Alternaria panax had strong chemotactic response at the low-concentration of total ginsenosides (cultivation temperature was 25 degrees C and pH value was 6), and the data of chemotactic migration index (CMI) was 1.235 4, chemotactic growth rate (CGR) was 0.537 0, spore germination rate (SGR) was 67%, and dry weight of mycelial (DWM) was 0.494 8 g x L(-1). The results indicated that the low and middle concentration (2, 20 mg x L(-1)) of total ginsenosides had significant promoting effect on chemotactic response of these two pathogens, and the spore germination, mycelial growth rate, dry weight of mycelial of them were also significantly improved by this chemotactic response, whereas it decreased as the increase of total ginsenosides concentration. PMID:26975095

  12. Allergic bronchopulmonary mycosis due to Alternaria: Case report and review.

    PubMed

    Singh, Bhagteshwar; Denning, David W

    2012-01-01

    While allergic bronchopulmonary aspergillosis and mycosis are well recognised, no cases have been described related to Alternaria spp. Alternaria is a common sensitising fungus in asthmatics and related to thunderstorm asthma. We report a case of an asthmatic who presented with worsening asthma control, mild eosinophilia on high dose inhaled corticosteroids (800 μg/day), a total IgE of 3800 KIU/L, an Alternaria-specific IgE of 21.3 KUa/L and positive skin prick test, negative specific IgE and skin prick test to Aspergillus fumigatus, Penicillium spp., Cladosporium spp., Trichophyton spp. and a normal CT scan of the thorax. He responded well to a short course of oral prednisolone and then oral itraconazole, given over 17 months but relapsed 1 month after stopping it. PMID:24371728

  13. 40 CFR 180.1256 - Alternaria destruens strain 059; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Alternaria destruens strain 059... RESIDUES IN FOOD Exemptions From Tolerances § 180.1256 Alternaria destruens strain 059; exemption from the... the microbial pesticide Alternaria destruens Strain 059 when used in or on all raw...

  14. Cutaneous Alternariosis Caused by Alternaria infectoria: Three Cases in Kidney Transplant Patients.

    PubMed

    Lopes, Leonor; Borges-Costa, João; Soares-Almeida, Luís; Filipe, Paulo; Neves, Fernanda; Santana, Alice; Guerra, José; Kutzner, Heinz

    2013-01-01

    The genus Alternaria has more than 80 species. Alternaria alternata and Alternaria infectoria are the most frequent species associated with infections in humans. Their clinical importance lies in the growing number of cases reported in immunocompromised patients. Herein, we report three cases of kidney-transplanted patients with different clinical presentations of cutaneous alternariosis and we discuss the treatment options. PMID:27429134

  15. Cutaneous Alternariosis Caused by Alternaria infectoria: Three Cases in Kidney Transplant Patients

    PubMed Central

    Lopes, Leonor; Borges-Costa, João; Soares-Almeida, Luís; Filipe, Paulo; Neves, Fernanda; Santana, Alice; Guerra, José; Kutzner, Heinz

    2013-01-01

    The genus Alternaria has more than 80 species. Alternaria alternata and Alternaria infectoria are the most frequent species associated with infections in humans. Their clinical importance lies in the growing number of cases reported in immunocompromised patients. Herein, we report three cases of kidney-transplanted patients with different clinical presentations of cutaneous alternariosis and we discuss the treatment options. PMID:27429134

  16. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Regulated articles for Asian citrus psyllid and citrus... Greening and Asian Citrus Psyllid § 301.76-2 Regulated articles for Asian citrus psyllid and citrus greening. The following are regulated articles for Asian citrus psyllid and citrus greening: (a) All...

  17. Data on morphological features of mycosis induced by Colletotrichum nymphaeae and Lecanicillium longisporum on citrus orthezia scale.

    PubMed

    Mascarin, Gabriel Moura; Guarín-Molina, Juan Humberto; Arthurs, Steven Paul; Humber, Richard Alan; de Andrade Moral, Rafael; Demétrio, Clarice Garcia Borges; Delalibera, Ítalo

    2016-09-01

    We describe symptoms of mycosis induced by two native fungal entomopathogens of the citrus orthezia scale, Praelongorthezia praelonga (Hemiptera: Ortheziidae), an important pest of citrus orchards. The data presented in this article are related to the article entitled "Seasonal prevalence of the insect pathogenic fungus Colletotrichum nymphaeae in Brazilian citrus groves under different chemical pesticide regimes" [1]. The endemic fungal pathogen, C. nymphaeae, emerges through the thin cuticular intersegmental regions of the citrus orthezia scale body revealing orange salmon-pigmented conidiophores bearing conidial masses, as well as producing rhizoid-like hyphae that extend over the citrus leaf. By contrast, nymphs or adult females of this scale insect infected with Lecanicillium longisporum exhibit profuse outgrowth of bright white-pigmented conidiophores with clusters of conidia emerging from the insect intersegmental membranes, and mycosed cadavers are commonly observed attached to the leaf surface by hyphal extensions. These morphological differences are important features to discriminate these fungal entomopathogens in citrus orthezia scales. PMID:27274531

  18. Pulmonary hypersensitivity to Alternaria and Aspergillus in baker's asthma.

    PubMed

    Klaustermeyer, W B; Bardana, E J; Hale, F C

    1977-05-01

    In two cases of baker's asthma pulmonary hypersensitivity was found to the fungi Alternaria and Aspergillus. Provocative bronchial challenge revealed a dual response; an immediate and an Arthus type hypersensitivity to Aspergillus in the first case. A primary binding assay revealed high titres of anti-Aspergillus antibody in the serum. In the second case intradermal and bronchial challenge suggested an immediate type I hypersensitivity response to Alternaria. The suspected organisms were present in the room air of the bakeries. It is suggested that an immunological response to these airborne fungi may have contributed to the pathogenesis of baker's asthma. PMID:561668

  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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 Aw) and two that form a phylogenetically distinct clade and originated in South America (B and C). Every X. citri strain carries multiple DNA fragme...

  20. Deep sequencing of small RNAs from citrus affected by graft-transmissible diseases of unknown etiology leads to discovery of two novel viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus is susceptible to graft-transmissible pathogens; some of which are arthropod-transmitted. Citrus cultivars vary in susceptibility or tolerance to these pathogens and may remain symptomless when infected. Established tests for known disease agents are used in certification and disease manage...

  1. Secondary metabolite profiling of Alternaria dauci, A. porri, A. solani, and A. tomatophila.

    PubMed

    Andersen, Birgitte; Dongo, Anita; Pryor, Barry M

    2008-02-01

    Chemotaxonomy (secondary metabolite profiling) has been shown to be of great value in the classification and differentiation in Ascomycota. However, few studies have investigated the use of metabolite production for classification and identification purposes of plant pathogenic Alternaria species. The purpose of the present study was to describe the methodology behind metabolite profiling in chemotaxonomy using A. dauci, A. porri, A. solani, and A. tomatophila strains as examples of the group. The results confirmed that A. dauci, A. solani, and A. tomatophila are three distinct species each with their own specific metabolite profiles, and that A. solani and A. tomatophila both produce altersolanol A, altertoxin I, and macrosporin. By using automated chemical image analysis and other multivariate statistic analyses, three sets of species-specific metabolites could be selected, one each for A. dauci, A. solani, and A. tomatophila. PMID:18262401

  2. Developing Transgenic Citrus for Resistance to Huanglongbing and Citrus Canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) and Citrus Bacterial Canker (CBC) are serious threats to citrus production, and resistant transgenic citrus is desirable. Genes for antimicrobial peptides (AMPs) with diverse promoters have been used to generate thousands of rootstock and scion transformants. D35S::D4E1 transfor...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  4. Citrus stubborn disease incidence determined by quantitative real time PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantitative real-time (q) PCR was developed for detection of Spiroplasma citri, the causal agent of citrus stubborn disease (CSD), using the DNA binding fluorophore SYBR Green I. The primer pair, P58-3f/4r, developed based on sequences from the P58 putative adhesin multigene of the pathogen result...

  5. Asian citrus psyllid genome (Diaphorina citri, Hemiptera)-Update 2013

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The psyllid genome is a scientific breakthrough that opens the psyllid genetic blueprint to investigations of all questions ranging from taxonomic origins to the understanding of developmental biology, to the acquisition and transmission of pathogens. The Asian citrus psyllid, Diaphorina citri (Hemi...

  6. Genetic variability in the pistachio late blight fungus, Alternaria alternata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic variation in the pistachio late blight fungus, Alternaria alternata, was investigated by restriction fragment length polymorphism (RFLP) in the rDNA region. Southern hybridization of EcoRI, HindIII, and Xbal digested fungal DNA with a RNA probe derived from Alt1, an rDNA clone isolated from ...

  7. Draft Genome Sequence of Alternaria alternata ATCC 34957.

    PubMed

    Nguyen, Hai D T; Lewis, Christopher T; Lévesque, C André; Gräfenhan, Tom

    2016-01-01

    We report the draft genome sequence of Alternaria alternata ATCC 34957. This strain was previously reported to produce alternariol and alternariol monomethyl ether on weathered grain sorghum. The genome was sequenced with PacBio technology and assembled into 27 scaffolds with a total genome size of 33.5 Mb. PMID:26769939

  8. TWO NEW SPECIES OF ALTERNARIA FROM PEAR FRUIT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During studies conducted over the past 15 years of various diseases of deciduous tree fruit from around the world, hundreds of Alternaria isolates have been made and characterized using morphological and molecular methods. Two such fungi are newly described here as A. calycipyricola sp. nov. from th...

  9. Amino acids implicated in plant defense are higher in Candidatus Liberibacter asiaticus-tolerant citrus varieties.

    PubMed

    Killiny, Nabil; Hijaz, Faraj

    2016-04-01

    Citrus Huanglongbing (HLB), also known as citrus greening, has been threatening the citrus industry since the early 1900's and up to this date there are no effective cures for this disease. Field observations and greenhouse controlled studies demonstrated that some citrus genotypes are more tolerant to Candidatus Liberibacter asiaticus (CLas) pathogen than others. However, the mechanisms underpinning tolerance has not been determined yet. The phloem sap composition of CLas-tolerant and sensitive citrus varieties was studied to identify metabolites that could be responsible for their tolerance to CLas. The citrus phloem sap was collected by centrifugation and was analyzed with gas chromatography-mass spectrometry after methyl chloroformate derivatization. Thirty-three metabolites were detected in the phloem sap of the studied varieties: twenty 20 amino acids, eight 8 organic acids, and five 5 fatty acids. Interestingly, the levels of most amino acids, especially those implicated in plantdefense to pathogens such as phenylalanine, tyrosine, tryptophan, lysine, and asparagine were higher in tolerant varieties. Although the level of organic acids varied between cultivars, this variation was not correlated with citrus resistance to CLas and could be cultivar specific. The fatty acids were found in trace amounts and in most cases their levels were not significantly different among varieties. Better understanding of the mechanisms underpinning citrus tolerance to CLas will help in developing economically tolerant varieties. PMID:27057814

  10. Airborne fungal spores of Alternaria, meteorological parameters and predicting variables

    NASA Astrophysics Data System (ADS)

    Filali Ben Sidel, Farah; Bouziane, Hassan; del Mar Trigo, Maria; El Haskouri, Fatima; Bardei, Fadoua; Redouane, Abdelbari; Kadiri, Mohamed; Riadi, Hassane; Kazzaz, Mohamed

    2015-03-01

    Alternaria is frequently found as airborne fungal spores and is recognized as an important cause of respiratory allergies. The aerobiological monitoring of fungal spores was performed using a Burkard volumetric spore traps. To establish predicting variables for daily and weakly spore counts, a stepwise multiple regression between spore concentrations and independent variables (meteorological parameters and lagged values from the series of spore concentrations: previous day or week concentration (Alt t - 1) and mean concentration of the same day or week in other years ( C mean)) was made with data obtained during 2009-2011. Alternaria conidia are present throughout the year in the atmosphere of Tetouan, although they show important seasonal fluctuations. The highest levels of Alternaria spores were recorded during the spring and summer or autumn. Alternaria showed maximum daily values in April, May or October depending on year. When the spore variables of Alternaria, namely C mean and Alt t - 1, and meteorological parameters were included in the equation, the resulting R 2 satisfactorily predict future concentrations for 55.5 to 81.6 % during the main spore season and the pre-peak 2. In the predictive model using weekly values, the adjusted R 2 varied from 0.655 to 0.676. The Wilcoxon test was used to compare the results from the expected values and the pre-peak spore data or weekly values for 2012, indicating that there were no significant differences between series compared. This test showed the C mean, Alt t - 1, frequency of the wind third quadrant, maximum wind speed and minimum relative humidity as the most efficient independent variables to forecast the overall trend of this spore in the air.

  11. Comparative phylogenomics and multi-gene cluster analyses of the CitrusHuanglongbing (HLB)-associated bacterium Candidatus Liberibacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB, previously known as citrus greening), is associated with Candidatus Liberibacter species and is a serious threat to citrus production world-wide. The pathogen is a Gram negative, unculturable, phloem-limited bacterium with limited known genomic information. Expanding the genetic ...

  12. Comparative Genomics and Phylogenetic Analyses of Newly Cloned Genomic Regions From the Citrus Huanglongbing (HLB)-associated Bacterium Candidatus Liberibacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), or citrus greening disease, caused by Candidatus Liberibacter species, is a serious threat to citrus production worldwide. The pathogen is a gram negative, unculturable, phloem-limited bacterium, with little known genomic information. Here, we report cloning and characterizatio...

  13. Deciphering the bacterial microbiome of citrus plants in response to ‘Candidatus Liberibacter asiaticus’-infection and antibiotic treatment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), the most devastating citrus disease worldwide, is vectored by phloem-feeding insects, and the pathogen in the USA is Candidatus Liberibacter asiaticus (Las). The bacterial microbiome of citrus after Las-infection and treatments with ampicillin (Amp) and gentamicin (Gm) was chara...

  14. Characteristics of the perception of different severity measures of citrus canker and the relations between the various symptom types

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker is a disease of citrus and is caused by the bacterial pathogen Xanthomonas axonopodis pv citri (Xac). Ways of managing the disease are being sought, and accurate, precise, reproducible disease assessment is needed for monitoring epidemics. The objective of this study was to investigate...

  15. 75 FR 17289 - Citrus Seed Imports; Citrus Greening and Citrus Variegated Chlorosis

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-06

    ... Animal and Plant Health Inspection Service 7 CFR Part 319 RIN 0579-AD07 Citrus Seed Imports; Citrus Greening and Citrus Variegated Chlorosis AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION... Internet at ( http://www.aphis.usda.gov ). FOR FURTHER INFOMATION CONTACT: Dr. Arnold Tschanz, Senior...

  16. The Distribution of Coumarins and Furanocoumarins in Citrus Species Closely Matches Citrus Phylogeny and Reflects the Organization of Biosynthetic Pathways

    PubMed Central

    Dugrand-Judek, Audray; Olry, Alexandre; Hehn, Alain; Costantino, Gilles; Ollitrault, Patrick; Froelicher, Yann; Bourgaud, Frédéric

    2015-01-01

    Citrus plants are able to produce defense compounds such as coumarins and furanocoumarins to cope with herbivorous insects and pathogens. In humans, these chemical compounds are strong photosensitizers and can interact with medications, leading to the “grapefruit juice effect”. Removing coumarins and furanocoumarins from food and cosmetics imply additional costs and might alter product quality. Thus, the selection of Citrus cultivars displaying low coumarin and furanocoumarin contents constitutes a valuable alternative. In this study, we performed ultra-performance liquid chromatography coupled with mass spectrometry analyses to determine the contents of these compounds within the peel and the pulp of 61 Citrus species representative of the genetic diversity all Citrus. Generally, Citrus peel contains larger diversity and higher concentrations of coumarin/furanocoumarin than the pulp of the same fruits. According to the chemotypes found in the peel, Citrus species can be separated into 4 groups that correspond to the 4 ancestral taxa (pummelos, mandarins, citrons and papedas) and extended with their respective secondary species descendants. Three of the 4 ancestral taxa (pummelos, citrons and papedas) synthesize high amounts of these compounds, whereas mandarins appear practically devoid of them. Additionally, all ancestral taxa and their hybrids are logically organized according to the coumarin and furanocoumarin pathways described in the literature. This organization allows hypotheses to be drawn regarding the biosynthetic origin of compounds for which the biogenesis remains unresolved. Determining coumarin and furanocoumarin contents is also helpful for hypothesizing the origin of Citrus species for which the phylogeny is presently not firmly established. Finally, this work also notes favorable hybridization schemes that will lead to low coumarin and furanocoumarin contents, and we propose to select mandarins and Ichang papeda as Citrus varieties for use in

  17. Morphological, molecular and virulence characterization of three Lencanicillium species infecting Asian citrus psyllids in Huangyan citrus groves.

    PubMed

    Lu, Lianming; Cheng, Baoping; Du, Danchao; Hu, Xiurong; Peng, Aitian; Pu, Zhanxu; Zhang, Xiaoya; Huang, Zhendong; Chen, Guoqing

    2015-02-01

    Citrus greening or Huanglongbing (HLB) is caused by the infection of Candidatus Liberibacter spp. in citrus plants. Since Asian citrus psyllid is the primary vector of this bacterial pathogen, the spread of HLB can be mitigated by suppressing Asian citrus psyllid populations in citrus groves using entomopathogens. To expand the current data on entomopathogens infecting Asian citrus psyllids, we isolated and characterized three different entomopathogens. Strains ZJLSP07, ZJLA08, and ZJLP09 infected the Asian citrus psyllid, Diaphorina citri Kuwayama, in Huangyan citrus groves. Based on molecular and morphological analyses, two were identified as Lecanicillium attenuatum and Lecanicillium psalliotae, and the third was recognized as an unidentified species of the genus, Lecanicillium. The corrected mortalities caused by strains ZJLSP07, ZJLA08 were 100% at 7days post-inoculation, while by ZJLP09 complete mortality occurred at 6days after inoculation, with 1.0×10(8)conidia/ml at 25°C and a relative humidity of 90% in the laboratory. Under the same condition, the corrected mortalities caused by strains ZJLSP07, ZJLA08 and ZJLP09 were 100%, 92.55% and 100%, respectively at 9days post-inoculation in the greenhouse. Our findings also revealed that these fungal strains infected D. citri using hyphae that penetrated deep into the insect tissues. Further, all three strains secreted the enzymes proteinases, chitinases and lipases with a potential to destroy insect tissues. Interestingly, strain ZJLP09 had an earlier invasion time and the highest levels of enzyme activities when compared to the other two strains. These findings have expanded the existing pool of entomopathogenic fungi that infect D. citri and can be potentially used for the management of D. citri populations. PMID:25593036

  18. Seasonal Movement Patterns and Long-Range Dispersal of Asian Citrus Psyllid in Florida Citrus.

    PubMed

    Lewis-Rosenblum, Hannah; Martini, Xavier; Tiwari, Siddharth; Stelinski, Lukasz L

    2015-02-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama, is the vector of the bacterial pathogen, Candidatus Liberibacter asiaticus, which is the causal agent of huanglongbing (HLB) in the United States. Both short-range and long-range dispersal of D. citri adults affect the spread of HLB; however, little is known about the long-range dispersal capabilities of D. citri in the field or the seasonality of flight behavior. In the present study, an in situ protein marking technique was used to determine the dispersal of D. citri by trapping marked adults under natural field conditions. D. citri movement from abandoned citrus groves to adjacent managed citrus groves was greatest during the spring and summer months and decreased significantly during the colder months (September-March). D. citri were able to traverse potential geographic barriers such as roads and fallow fields. In an experiment conducted to determine long-range dispersal capacity in the absence of severe weather events, D. citri were able to disperse at least 2 km within 12 d. Wind direction was not correlated with the number of marked psyllids captured, indicating substantial flight capability by D. citri. Finally, the number of marked psyllids captured increased with the density of emerging young leaves on surrounding trees. The results confirm that abandoned citrus groves in Florida serve as reservoirs for D. citri, which can disperse across long distances despite geographical barriers. PMID:26470097

  19. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Quarantined areas; citrus greening and Asian citrus...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid § 301.76-3 Quarantined areas; citrus greening and Asian citrus...

  20. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Quarantined areas; citrus greening and Asian citrus...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid § 301.76-3 Quarantined areas; citrus greening and Asian citrus...

  1. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Quarantined areas; citrus greening and Asian citrus...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid § 301.76-3 Quarantined areas; citrus greening and Asian citrus...

  2. Anastomosis Is Required for Virulence of the Fungal Necrotroph Alternaria brassicicola▿

    PubMed Central

    Craven, Kelly D.; Vélëz, Heriberto; Cho, Yangrae; Lawrence, Christopher B.; Mitchell, Thomas K.

    2008-01-01

    A fungal mycelium is typically composed of radially extending hyphal filaments interconnected by bridges created through anastomoses. These bridges facilitate the dissemination of nutrients, water, and signaling molecules throughout the colony. In this study, we used targeted gene deletion and nitrate utilization mutants of the cruciferous pathogen Alternaria brassicicola and two closely related species to investigate hyphal fusion (anastomosis) and its role in the ability of fungi to cause disease. All eight of the A. brassicicola isolates tested, as well as A. mimicula and A. japonica, were capable of self-fusion, with two isolates of A. brassicicola being capable of non-self-fusion. Disruption of the anastomosis gene homolog (Aso1) in A. brassicicola resulted in both the loss of self-anastomosis and pathogenicity on cabbage. This finding, combined with our discovery that a previously described nonpathogenic A. brassicicola mutant defective for a mitogen-activated protein kinase gene (amk1) also lacked the capacity for self-anastomosis, suggests that self-anastomosis is associated with pathogenicity in A. brassicicola. PMID:18310356

  3. Antioxidant activity of Citrus fruits.

    PubMed

    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. PMID:26593569

  4. Sesquiterpene emissions from Alternaria alternata and Fusarium oxysporum: Effects of age, nutrient availability, and co-cultivation

    PubMed Central

    Weikl, Fabian; Ghirardo, Andrea; Schnitzler, Jörg-Peter; Pritsch, Karin

    2016-01-01

    Alternaria alternata is one of the most studied fungi to date because of its impact on human life – from plant pathogenicity to allergenicity. However, its sesquiterpene emissions have not been systematically explored. Alternaria regularly co-occurs with Fusarium fungi, which are common plant pathogens, on withering plants. We analyzed the diversity and determined the absolute quantities of volatile organic compounds (VOCs) in the headspace above mycelial cultures of A. alternata and Fusarium oxysporum under different conditions (nutrient rich and poor, single cultures and co-cultivation) and at different mycelial ages. Using stir bar sorptive extraction and gas chromatography–mass spectrometry, we observed A. alternata to strongly emit sesquiterpenes, particularly during the early growth stages, while emissions from F. oxysporum consistently remained comparatively low. The emission profile characterizing A. alternata comprised over 20 sesquiterpenes with few effects from nutrient quality and age on the overall emission profile. Co-cultivation with F. oxysporum resulted in reduced amounts of VOCs emitted from A. alternata although its profile remained similar. Both fungi showed distinct emission profiles, rendering them suitable biomarkers for growth-detection of their phylotype in ambient air. The study highlights the importance of thorough and quantitative evaluations of fungal emissions of volatile infochemicals such as sesquiterpenes. PMID:26915756

  5. Sesquiterpene emissions from Alternaria alternata and Fusarium oxysporum: Effects of age, nutrient availability, and co-cultivation.

    PubMed

    Weikl, Fabian; Ghirardo, Andrea; Schnitzler, Jörg-Peter; Pritsch, Karin

    2016-01-01

    Alternaria alternata is one of the most studied fungi to date because of its impact on human life - from plant pathogenicity to allergenicity. However, its sesquiterpene emissions have not been systematically explored. Alternaria regularly co-occurs with Fusarium fungi, which are common plant pathogens, on withering plants. We analyzed the diversity and determined the absolute quantities of volatile organic compounds (VOCs) in the headspace above mycelial cultures of A. alternata and Fusarium oxysporum under different conditions (nutrient rich and poor, single cultures and co-cultivation) and at different mycelial ages. Using stir bar sorptive extraction and gas chromatography-mass spectrometry, we observed A. alternata to strongly emit sesquiterpenes, particularly during the early growth stages, while emissions from F. oxysporum consistently remained comparatively low. The emission profile characterizing A. alternata comprised over 20 sesquiterpenes with few effects from nutrient quality and age on the overall emission profile. Co-cultivation with F. oxysporum resulted in reduced amounts of VOCs emitted from A. alternata although its profile remained similar. Both fungi showed distinct emission profiles, rendering them suitable biomarkers for growth-detection of their phylotype in ambient air. The study highlights the importance of thorough and quantitative evaluations of fungal emissions of volatile infochemicals such as sesquiterpenes. PMID:26915756

  6. Huanglongbing: An overview of a complex pathosystem ravaging the world's citrus.

    PubMed

    da Graça, John V; Douhan, Greg W; Halbert, Susan E; Keremane, Manjunath L; Lee, Richard F; Vidalakis, Georgios; Zhao, Hongwei

    2016-04-01

    Citrus huanglongbing (HLB) has become a major disease and limiting factor of production in citrus areas that have become infected. The destruction to the affected citrus industries has resulted in a tremendous increase to support research that in return has resulted in significant information on both applied and basic knowledge concerning this important disease to the global citrus industry. Recent research indicates the relationship between citrus and the causal agent of HLB is shaped by multiple elements, in which host defense responses may also play an important role. This review is intended to provide an overview of the importance of HLB to a wider audience of plant biologists. Recent advances on host-pathogen interactions, population genetics and vectoring of the causal agent are discussed. PMID:26466921

  7. Citrus stubborn disease (CSD)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    CSD is caused by Spiroplasma citri, a phloem-limited, cell-wall-less bacterium. S. citri is transmitted in a propagative, circulative manner by several leafhoppers including Circulifer tenellus and Scaphytopius nitridus in citrus-growing regions of California and Arizona and by C. haematoceps (syn....

  8. Citrus Leafminer Mating Disruption

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mating disruption targets a specific pest and has no negative impact on natural enemies, the environment, or agricultural workers. A flowable wax dispenser was tested for releasing the female sex pheromone of the citrus leafminer, Phyllocnistis citrella. These dispensers are biodegradable, inexpens...

  9. Comparison of enzyme immunoassay–based assays for environmental Alternaria alternata

    PubMed Central

    Barnes, Charles; Portnoy, Jay; Sever, Michelle; Arbes, Samuel; Vaughn, Ben; Zeldin, Darryl C.

    2007-01-01

    Background Alternaria alternata–derived allergenic materials are causes of human disease. Several immunoassays exist to quantify these materials. Objective To compare methods for evaluating Alternaria content. Methods Four methods, including 1 monoclonal antibody (MAb)–based assay specific for recombinant Alt a 1, 1 MAb-based assay for chromatographically purified Alt a 1, 1 polyclonal antibody (PAb)–based assay for chromatographically purified Alt a 1, and 1 PAb-based assay for whole Alternaria extract, were evaluated. Environmental samples collected as part of the National Survey of Lead and Allergens in Housing were examined. Alternaria spore counts were determined in dust by observation. Results The MAb-based assay for recombinant Alt a 1 detected Alternaria in few samples (25%); the PAb-based assay for whole Alternaria proteins detected antigen in 97% of the samples. The PAb- and MAb-based assays for purified Alt a 1 detected antigen in 100% of the samples. There was a significant positive correlation between the 2 assays directed against purified Alt a 1. There was a positive correlation between the PAb-based assay for whole Alternaria and the PAb-based assay for Alt a 1. Nearly all the dust samples contained Alternaria spores, and there was a strong positive correlation between counts and all assays. Conclusion Because of the multifaceted nature of Alternaria, the disparities between methods for quantifying Alternaria, the cross-reactivity between fungal allergens, and the documented genetic promiscuity of this fungus, enzyme immunoassays using PAbs against a range of Alternaria proteins will probably produce the most reliable estimation of overall Alternaria exposure in house dust. PMID:17042141

  10. Ex Vivo Application of Secreted Metabolites Produced by Soil-Inhabiting Bacillus spp. Efficiently Controls Foliar Diseases Caused by Alternaria spp.

    PubMed Central

    El-Sayed, Ashraf S. A.; Patel, Jaimin S.; Green, Kari B.; Ali, Mohammad; Brennan, Mary; Norman, David

    2015-01-01

    Bacterial biological control agents (BCAs) are largely used as live products to control plant pathogens. However, due to variable environmental and ecological factors, live BCAs usually fail to produce desirable results against foliar pathogens. In this study, we investigated the potential of cell-free culture filtrates of 12 different bacterial BCAs isolated from flower beds for controlling foliar diseases caused by Alternaria spp. In vitro studies showed that culture filtrates from two isolates belonging to Bacillus subtilis and Bacillus amyloliquefaciens displayed strong efficacy and potencies against Alternaria spp. The antimicrobial activity of the culture filtrate of these two biological control agents was effective over a wider range of pH (3.0 to 9.0) and was not affected by autoclaving or proteolysis. Comparative liquid chromatography-mass spectrometry (LC-MS) analyses showed that a complex mixture of cyclic lipopeptides, primarily of the fengycin A and fengycin B families, was significantly higher in these two BCAs than inactive Bacillus spp. Interaction studies with mixtures of culture filtrates of these two species revealed additive activity, suggesting that they produce similar products, which was confirmed by LC-tandem MS analyses. In in planta pre- and postinoculation trials, foliar application of culture filtrates of B. subtilis reduced lesion sizes and lesion frequencies caused by Alternaria alternata by 68 to 81%. Taken together, our studies suggest that instead of live bacteria, culture filtrates of B. subtilis and B. amyloliquefaciens can be applied either individually or in combination for controlling foliar diseases caused by Alternaria species. PMID:26519395

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

    PubMed Central

    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. PMID:27499757

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

    PubMed

    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. PMID:27499757

  13. Citrus stubborn symptom severity and Spiroplasma citri location within the tress canopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The severity of symptoms of citrus stubborn disease (CSD) within an orchard can range from mild to severe, but whether factors other than pathogen titer or duration of infection impact severity is not known. We tested the hypothesis that the canopy distribution of the pathogen, Spiroplasma citri, i...

  14. Antimicrobial activity of acid-hydrolyzed Citrus unshiu peel extract in milk.

    PubMed

    Min, Keun Young; Kim, Hyun Jung; Lee, Kyoung Ah; Kim, Kee-Tae; Paik, Hyun-Dong

    2014-01-01

    Citrus fruit (Citrus unshiu) peels were extracted with hot water and then acid-hydrolyzed using hydrochloric acid. Antimicrobial activities of acid-hydrolyzed Citrus unshiu peel extract were evaluated against pathogenic bacteria, including Bacillus cereus, Staphylococcus aureus, and Listeria monocytogenes. Antilisterial effect was also determined by adding extracts at 1, 2, and 4% to whole, low-fat, and skim milk. The cell numbers of B. cereus, Staph. aureus, and L. monocytogenes cultures treated with acid-hydrolyzed extract for 12h at 35°C were reduced from about 8log cfu/mL to <1log cfu/mL. Bacillus cereus was more sensitive to acid-hydrolyzed Citrus unshiu peel extract than were the other bacteria. The addition of 4% acid-hydrolyzed Citrus unshiu extracts to all types of milk inhibited the growth of L. monocytogenes within 1d of storage at 4°C. The results indicated that Citrus unshiu peel extracts, after acid hydrolysis, effectively inhibited the growth of pathogenic bacteria. These findings indicate that acid hydrolysis of Citrus unshiu peel facilitates its use as a natural antimicrobial agent for food products. PMID:24534507

  15. Daily variations of Alternaria spores in the city of Murcia (semi-arid southeastern Spain)

    NASA Astrophysics Data System (ADS)

    Munuera Giner, M.; Carrión García, J. S.

    1995-12-01

    Annual variations in the abundance of Alternaria spores were related to the length of the spore period for data from Murcia (southeastern Spain). To understand the relationship between the number of spores and climatic factors, Alternaria spore counts for March 1993 to February 1994 were examined by means of correlation and regression analyses with fourteen different weather parameters. The results indicated that there was a tendency for Alternaria spore concentrations to increase with increases in temperature, wind speed and hours of sunshine. Negative correlations were observed with air pressure, wind direction and humidity. Theoretical curves for Alternaria spore counts are given in relation to temperatures during the period studied.

  16. Partial Resistance of Carrot to Alternaria dauci Correlates with In Vitro Cultured Carrot Cell Resistance to Fungal Exudates

    PubMed Central

    Voisine, Linda; Gatto, Julia; Hélesbeux, Jean-Jacques; Séraphin, Denis; Peña-Rodriguez, Luis M.; Richomme, Pascal; Boedo, Cora; Yovanopoulos, Claire; Gyomlai, Melvina; Briard, Mathilde; Simoneau, Philippe; Poupard, Pascal; Berruyer, Romain

    2014-01-01

    Although different mechanisms have been proposed in the recent years, plant pathogen partial resistance is still poorly understood. Components of the chemical warfare, including the production of plant defense compounds and plant resistance to pathogen-produced toxins, are likely to play a role. Toxins are indeed recognized as important determinants of pathogenicity in necrotrophic fungi. Partial resistance based on quantitative resistance loci and linked to a pathogen-produced toxin has never been fully described. We tested this hypothesis using the Alternaria dauci – carrot pathosystem. Alternaria dauci, causing carrot leaf blight, is a necrotrophic fungus known to produce zinniol, a compound described as a non-host selective toxin. Embryogenic cellular cultures from carrot genotypes varying in resistance against A. dauci were confronted with zinniol at different concentrations or to fungal exudates (raw, organic or aqueous extracts). The plant response was analyzed through the measurement of cytoplasmic esterase activity, as a marker of cell viability, and the differentiation of somatic embryos in cellular cultures. A differential response to toxicity was demonstrated between susceptible and partially resistant genotypes, with a good correlation noted between the resistance to the fungus at the whole plant level and resistance at the cellular level to fungal exudates from raw and organic extracts. No toxic reaction of embryogenic cultures was observed after treatment with the aqueous extract or zinniol used at physiological concentration. Moreover, we did not detect zinniol in toxic fungal extracts by UHPLC analysis. These results suggest that strong phytotoxic compounds are present in the organic extract and remain to be characterized. Our results clearly show that carrot tolerance to A. dauci toxins is one component of its partial resistance. PMID:24983469

  17. Population genetic analysis reveals cryptic sex in the phytopathogenic fungus Alternaria alternata

    PubMed Central

    Meng, Jing-Wen; Zhu, Wen; He, Meng-Han; Wu, E-Jiao; Duan, Guo-Hua; Xie, Ye-Kun; Jin, Yu-Jia; Yang, Li-Na; Shang, Li-Ping; Zhan, Jiasui

    2015-01-01

    Reproductive mode can impact population genetic dynamics and evolutionary landscape of plant pathogens as well as on disease epidemiology and management. In this study, we monitored the spatial dynamics and mating type idiomorphs in ~700 Alternaria alternata isolates sampled from the main potato production areas in China to infer the mating system of potato early blight. Consistent with the expectation of asexual species, identical genotypes were recovered from different locations separated by hundreds of kilometers of geographic distance and spanned across many years. However, high genotype diversity, equal MAT1-1 and MAT1-2 frequencies within and among populations, no genetic differentiation and phylogenetic association between two mating types, combined with random association amongst neutral markers in some field populations, suggested that sexual reproduction may also play an important role in the epidemics and evolution of the pathogen in at least half of the populations assayed despite the fact that no teleomorphs have been observed yet naturally or artificially. Our results indicated that A. alternata may adopt an epidemic mode of reproduction by combining many cycles of asexual propagation with fewer cycles of sexual reproduction, facilitating its adaptation to changing environments and making the disease management on potato fields even more difficult. PMID:26666175

  18. Population genetic analysis reveals cryptic sex in the phytopathogenic fungus Alternaria alternata.

    PubMed

    Meng, Jing-Wen; Zhu, Wen; He, Meng-Han; Wu, E-Jiao; Duan, Guo-Hua; Xie, Ye-Kun; Jin, Yu-Jia; Yang, Li-Na; Shang, Li-Ping; Zhan, Jiasui

    2015-01-01

    Reproductive mode can impact population genetic dynamics and evolutionary landscape of plant pathogens as well as on disease epidemiology and management. In this study, we monitored the spatial dynamics and mating type idiomorphs in ~700 Alternaria alternata isolates sampled from the main potato production areas in China to infer the mating system of potato early blight. Consistent with the expectation of asexual species, identical genotypes were recovered from different locations separated by hundreds of kilometers of geographic distance and spanned across many years. However, high genotype diversity, equal MAT1-1 and MAT1-2 frequencies within and among populations, no genetic differentiation and phylogenetic association between two mating types, combined with random association amongst neutral markers in some field populations, suggested that sexual reproduction may also play an important role in the epidemics and evolution of the pathogen in at least half of the populations assayed despite the fact that no teleomorphs have been observed yet naturally or artificially. Our results indicated that A. alternata may adopt an epidemic mode of reproduction by combining many cycles of asexual propagation with fewer cycles of sexual reproduction, facilitating its adaptation to changing environments and making the disease management on potato fields even more difficult. PMID:26666175

  19. Zinc triggers signaling mechanisms and defense responses promoting resistance to Alternaria brassicicola in Arabidopsis thaliana.

    PubMed

    Martos, Soledad; Gallego, Berta; Cabot, Catalina; Llugany, Mercè; Barceló, Juan; Poschenrieder, Charlotte

    2016-08-01

    According to the elemental defense hypothesis the accumulation of trace elements by plants may substitute for organic defenses, while the joint effects hypothesis proposes that trace elements and organic defenses can have additive or synergistic effects against pathogens or herbivores. To evaluate these hypotheses the response of the pathosystem Alternaria brassicicola-Arabidopsis thaliana to control (2μM) and surplus (12μM) Zn was evaluated using the camalexin deficient mutant pad3-1 and mtp1-1, a mutant with impaired Zn vacuolar storage, along with the corresponding wildtypes. In vitro, a 50% inhibition of fungal growth was achieved by 440μM Zn. A. thaliana leaves could accumulate equivalent concentrations without harm. In fact, surplus Zn enhanced the resistance of A. thaliana to fungal attack in Columbia (Col-0), Wassilewskija (WS), and mtp1-1. However, surplus Zn was unable to protect pad3-1 demonstrating that Zn cannot substitute for camalexin, the main organic defense in A. thaliana. High, non phytotoxic leaf Zn concentrations enhanced the resistance to A. brassicicola of A. thaliana genotypes able to produce camalexin. This was mainly due to Zn-induced enhancement of the JA/ETH signaling pathway leading to enhanced PAD3 expression. These results support the joint effects hypothesis and highlight the importance of adequate Zn supply for reinforced pathogen resistance. PMID:27297986

  20. Fungicidal activity of volatile oil from eucalyptus Citriodora Hook. against Alternaria triticina.

    PubMed

    Ramezani, Hesamedin

    2006-01-01

    Use of plant products for the management of phytopathogenic fungi is fast becoming an important component of Integrated Disease Management (I.D.M.) programme. The natural plant products are bio-degradable and thus eco-friendly, are catching the attention of the scientist worldwide. Such products from higher plants are relatively broad spectrum, bio-efficacious, economical and environmentally safe. Among these essential oils from higher plants because of their greater inhibitory action are being explored preferably worldwide. In this context, a study was undertaken to explore the effect of volatile oil from Eucalyptus citriodora against Alternaria triticina. The radial growth, dry weight and spore germination of pathogen were drastically reduced in response to the different concentrations of volatile oil. A complete inhibition of radial growth, dry weight and spore germination were observed at 1500, 1000 and 100 ppm, respectively. In contrast, similar complete inhibition of test pathogen was observed at very high concentration (6500, 6500 and 1000 ppm) of mancozeb--a commercially available synthetic fungicide. Based on these observations, it was therefore concluded that eucalypt volatile oil has potential to suppress the phytopathogenic fungi. PMID:17390838

  1. Development of multiplex polymerase chain reaction assay for simultaneous detection of clostero-, badna- and mandari-viruses along with huanglongbing bacterium in citrus trees.

    PubMed

    Meena, Ram Prasnna; Baranwal, V K

    2016-09-01

    Citrus trees harbor a large number of viral and bacterial pathogens. Citrus yellow vein clearing virus (CYVCV), Indian citrus ringspot virus (ICRSV), Citrus yellow mosaic virus (CYMV), Citrus tristeza virus (CTV) and a bacterium, Candidatus Liberibacter asiaticus (CLa) associated with huanglongbing (HLB) disease, the most prevalent pathogens in citrus orchards of different regions in India and are responsible for debilitating citriculture. For detection of these viral and bacterial pathogens a quick, sensitive and cost effective detection method is required. With this objective a multiplex polymerase chain reaction (mPCR) assay was developed for simultaneous detection of four viruses and a bacterium in citrus. Several sets of primers were designed for each virus based on the retrieved reference sequences from the GenBank. A primer pair published previously was used for greening bacterium. Each pair of primers was evaluated for their sensitivity and differentiation by simplex and mPCR. The constant amplified products were identified on the basis of molecular size in mPCR and were compared with standard PCR. The amplicons were cloned and results were confirmed with sequencing analysis. The mPCR assay was validated using naturally infected field samples for one or more citrus viruses and the huanglongbing bacterium. The mPCR assay developed here will aid in the production of virus free planting materials and rapid indexing for certification of citrus budwood programme. PMID:27208471

  2. Metabolic Interplay between the Asian Citrus Psyllid and Its Profftella Symbiont: An Achilles’ Heel of the Citrus Greening Insect Vector

    PubMed Central

    Ramsey, John S.; Johnson, Richard S.; Hoki, Jason S.; Kruse, Angela; Mahoney, Jaclyn; Hilf, Mark E.; Hunter, Wayne B.; Hall, David G.; Schroeder, Frank C.; MacCoss, Michael J.; Cilia, Michelle

    2015-01-01

    ‘Candidatus Liberibacter asiaticus’ (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid. Interactions among D. citri and its microbial endosymbionts, including ‘Candidatus Profftella armatura’, are likely to impact transmission of CLas. We used quantitative mass spectrometry to compare the proteomes of CLas(+) and CLas(-) populations of D. citri, and found that proteins involved in polyketide biosynthesis by the endosymbiont Profftella were up-regulated in CLas(+) insects. Mass spectrometry analysis of the Profftella polyketide diaphorin in D. citri metabolite extracts revealed the presence of a novel diaphorin-related polyketide and the ratio of these two polyketides was changed in CLas(+) insects. Insect proteins differentially expressed between CLas(+) and CLas(-) D. citri included defense and immunity proteins, proteins involved in energy storage and utilization, and proteins involved in endocytosis, cellular adhesion, and cytoskeletal remodeling which are associated with microbial invasion of host cells. Insight into the metabolic interdependence between the insect vector, its endosymbionts, and the citrus greening pathogen reveals novel opportunities for control of this disease, which is currently having a devastating impact on citrus production worldwide. PMID:26580079

  3. Metabolic Interplay between the Asian Citrus Psyllid and Its Profftella Symbiont: An Achilles' Heel of the Citrus Greening Insect Vector.

    PubMed

    Ramsey, John S; Johnson, Richard S; Hoki, Jason S; Kruse, Angela; Mahoney, Jaclyn; Hilf, Mark E; Hunter, Wayne B; Hall, David G; Schroeder, Frank C; MacCoss, Michael J; Cilia, Michelle

    2015-01-01

    'Candidatus Liberibacter asiaticus' (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid. Interactions among D. citri and its microbial endosymbionts, including 'Candidatus Profftella armatura', are likely to impact transmission of CLas. We used quantitative mass spectrometry to compare the proteomes of CLas(+) and CLas(-) populations of D. citri, and found that proteins involved in polyketide biosynthesis by the endosymbiont Profftella were up-regulated in CLas(+) insects. Mass spectrometry analysis of the Profftella polyketide diaphorin in D. citri metabolite extracts revealed the presence of a novel diaphorin-related polyketide and the ratio of these two polyketides was changed in CLas(+) insects. Insect proteins differentially expressed between CLas(+) and CLas(-) D. citri included defense and immunity proteins, proteins involved in energy storage and utilization, and proteins involved in endocytosis, cellular adhesion, and cytoskeletal remodeling which are associated with microbial invasion of host cells. Insight into the metabolic interdependence between the insect vector, its endosymbionts, and the citrus greening pathogen reveals novel opportunities for control of this disease, which is currently having a devastating impact on citrus production worldwide. PMID:26580079

  4. Citrus Huanglongbing tolerance in Australian Citrus Relatives, Microcitrus and Eremocirus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tolerance, or resistance to citrus huanglongbing will be important as a long term solution for this disease. In a field trial conducted with over 1000 plants belonging to different genera in the sub-family Aurantioideae, we observed field tolerance in many Australian citrus relatives. To confirm the...

  5. Agreement: Citrus College Faculty Association and Citrus Community College District.

    ERIC Educational Resources Information Center

    Citrus Community Coll. District, Glendora, CA.

    The collective bargaining agreement between the Citrus Community College District Board of Trustees and the Citrus College Faculty/California Teachers Association/National Education Association is presented. This contract, covering the period from July 1988 through June 1990, deals with the following topics: bargaining agent recognition and…

  6. Expressed Genes in Asian Citrus Psyllid adults feeding on citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We created and described the first genetic data set from the Asian citrus psyllid, AsCP, Diaphorina citri, Kuwayama (Hemiptera: Psyllidae). The AsCP spread the plant-infecting bacterium, Candidatus Liberibacter asiaticus, which is associated with the citrus disease Huanglongbing, HLB, known as Citru...

  7. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Greening and Asian Citrus Psyllid § 301.76-3 Quarantined areas; citrus greening and Asian citrus psyllid... quarantined area for Asian citrus psyllid in accordance with the criteria listed in paragraph (c) of this... Asian citrus psyllid on the Plant Protection and Quarantine (PPQ) Web site:...

  8. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Regulated articles for Asian citrus psyllid and citrus...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid § 301.76-2 Regulated articles for Asian citrus psyllid and...

  9. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Regulated articles for Asian citrus psyllid and citrus...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid § 301.76-2 Regulated articles for Asian citrus psyllid and...

  10. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Regulated articles for Asian citrus psyllid and citrus...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid § 301.76-2 Regulated articles for Asian citrus psyllid and...

  11. Characterization of Citrus sinensis transcription factors closely associated with the non-host response to Xanthomonas campestris pv. vesicatoria.

    PubMed

    Daurelio, Lucas D; Romero, María S; Petrocelli, Silvana; Merelo, Paz; Cortadi, Adriana A; Talón, Manuel; Tadeo, Francisco R; Orellano, Elena G

    2013-07-01

    Plants, when exposed to certain pathogens, may display a form of genotype-independent resistance, known as non-host response. In this study, the response of Citrus sinensis (sweet orange) leaves to Xanthomonas campestris pv. vesicatoria (Xcv), a pepper and tomato pathogenic bacterium, was analyzed through biochemical assays and cDNA microarray hybridization and compared with Asiatic citrus canker infection caused by Xanthomonas citri subsp. citri. Citrus leaves exposed to the non-host bacterium Xcv showed hypersensitive response (HR) symptoms (cell death), a defense mechanism common in plants but poorly understood in citrus. The HR response was accompanied by differentially expressed genes that are associated with biotic stress and cell death. Moreover, 58 transcription factors (TFs) were differentially regulated by Xcv in citrus leaves, including 26 TFs from the stress-associated families AP2-EREBP, bZip, Myb and WRKY. Remarkably, in silico analysis of the distribution of expressed sequence tags revealed that 10 of the 58 TFs, belonging to C2C2-GATA, C2H2, CCAAT, HSF, NAC and WRKY gene families, were specifically over-represented in citrus stress cDNA libraries. This study identified candidate TF genes for the regulation of key steps during the citrus non-host HR. Furthermore, these TFs might be useful in future strategies of molecular breeding for citrus disease resistance. PMID:23453188

  12. Differential gene expression in Alternaria gaisen exposed to dark and light

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Character states observed during sporulation have been the basis for segregation and description of many of the small-spored species of Alternaria. Phylogenetic analyses of ITS and housekeeping genes from small-spored Alternaria spp. do not support most of the currently defined morphological specie...

  13. Alternaria roseogrisea, a new species from achenes of Helianthus annuus (sunflower)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternaria roseogrisea was isolated from the achenes of Helianthus annuus L. during studies conducted in 1983-85 to document the diversity of fungi occurring in sunflower seeds and the possible role these fungi play in degradation of oilseed quality. A. roseogrisea was reported as "Alternaria sp. 2...

  14. Leaf Petiole and Stem Blight Disease of Sweet Potato Caused by Alternaria Bataticola in Uganda

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternaria leaf petiole and stem blight is an important disease of sweet potato (Ipomoea batatus (L.) Lam.) in tropical and sub-tropical regions. In surveys conducted in Uganda from 2001 to 2003, disease incidence ranged from 0-49%. Symptoms of Alternaria leaf and stem blight disease consisted of sm...

  15. Modelling and visualizing morphology in the fungus Alternaria.

    PubMed

    Taralova, Ekaterina H; Schlecht, Joseph; Barnard, Kobus; Pryor, Barry M

    2011-11-01

    Alternaria is one of the most cosmopolitan fungal genera encountered and impacts humans and human activities in areas of material degradation, phytopathology, food toxicology, and respiratory disease. Contemporary methods of taxon identification rely on assessments of morphology related to sporulation, which are critical for accurate diagnostics. However, the morphology of Alternaria is quite complex, and precise characterization can be laborious, time-consuming, and often restricted to experts in this field. To make morphology characterization easier and more broadly accessible, a generalized statistical model was developed for the three-dimensional geometric structure of the sporulation apparatus. The model is inspired by the widely used grammar-based models for plants, Lindenmayer-systems, which build structure by repeated application of rules for growth. Adjusting the parameters of the underlying probability distributions yields variations in the morphology, and thus the approach provides an excellent tool for exploring the morphology of Alternaria under different assumptions, as well as understanding how it is largely the consequence of local rules for growth. Further, different choices of parameters lead to different model groups, which can then be visually compared to published descriptions or microscopy images to validate parameters for species-specific models. The approach supports automated analysis, as the models can be fit to image data using statistical inference, and the explicit representation of the geometry allows the accurate computation of any morphological quantity. Furthermore, because the model can encode the statistical variation of geometric parameters for different species, it will allow automated species identification from microscopy images using statistical inference. In summary, the approach supports visualization of morphology, automated quantification of phenotype structure, and identification based on form. PMID:22036294

  16. Influence of environmental parameters on mycotoxin production by Alternaria arborescens.

    PubMed

    Vaquera, Sandra; Patriarca, Andrea; Fernández Pinto, V

    2016-02-16

    Alternaria arborescens has been reported as a common fungal species invading tomatoes and is capable of producing several mycotoxins in infected plants, fruits and in agricultural commodities. Alternariol (AOH), alternariol monomethyl ether (AME), and tenuazonic acid (TeA) are some of the main Alternaria mycotoxins that can be found as contaminants of food. This species can produce these toxic metabolites together with AAL toxins (Alternaria alternata f. sp. lycopersicum toxins), which can act as inhibitors of sphingolipid biosynthesis. The objective of this study was to determine the effect of water activity (aw, 0.995, 0.975, 0.950) and temperature (6, 15, 20, 25 and 30 °C) on mycotoxin production by A. arborescens on a synthetic tomato medium. The optimum production of AOH and AME occurred at 0.975 aw after 40 days of incubation at 30 °C. The maximum TeA accumulation was observed at 0.975 aw and 25 °C and at 0.950 aw and 30 °C. AAL TA was produced in higher quantities at 0.995 aw and 30 °C. At 6 °C no quantifiable levels of AOH or AME were detected, but significant amounts of TeA were produced at 0.975 aw. In general, high aw levels and high temperatures were favorable for mycotoxin production. The greatest accumulation of all four toxins occurred at 0.975 aw and 30 °C. The results obtained here could be extrapolated to evaluate the risk of tomato fruits and tomato products contamination caused by these toxins. PMID:26708802

  17. Improved real-time PCR detection of Candidatus Liberibacter asiaticus from citrus and psyllid hosts by targeting the intragenic tandem repeats of its prophage genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Candidatus Liberibacter asiaticus (Las) is the most prevalent species of Liberibacter associated with citrus huanglongbing (HLB) worldwide. Residing in phloem sieve cells of host plants and vectored by the Asian citrus psyllid (Diaphorina citri), this fastidious bacterium lives as a pathogen or sym...

  18. Comparison of gene expression changes in susceptible, tolerant, and resistant hosts in response to infection with citrus tristeza virus and huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pathogens Candidatus Liberibacter asiaticus (Las) and Citrus tristeza virus (CTV) are both phloem limited and have significant economic impact on citrus production wherever they are found. Studies of host resistance have indicated that Poncirus trifoliata has tolerance or resistance to both path...

  19. Potential nutritional benefits of current citrus consumption

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus contains various 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 currently consumed. We then compared the amount of citrus and citrus-derived compounds that have been use...

  20. Can insecticides protect citrus from HLB infection?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hunanglongbing (HLB), or citrus greening, is a lethal bacterial disease of citrus causing devastating yield losses in Florida and many other citrus-growing areas of the world. The presumptive bacterial agent, C. Liberibacter asiaticus, is vectored by an exotic, invasive insect, Asian citrus psyllid...

  1. A new compound from an endophytic fungus Alternaria tenuissima.

    PubMed

    Wu, Wen-Bin; Yue, Gao-Chao; Huang, Qi-Lin; Sun, Ling-Ling; Zhang, Wen

    2014-01-01

    A new secondary metabolite, named altertoxin IV (1), together with altertoxin II (2), was isolated from the fermentation broth of Alternaria tenuissima, an endophytic fungal strain residing in the stem of Tribulus terrestris L. The structure of new compound 1 was established by HR-ESI-MS, multinuclear NMR spectroscopy, and single crystal X-ray diffraction method. In their in vitro bioassay, compound 2 exhibited moderate cytotoxic activity against PC-3 cell lines with an IC50 value of 14.28 μM. PMID:24660902

  2. Widespread applications of citrus cryopreservation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus genetic resources can now be successfully cryopreserved, which means that they can be placed into long-term storage at liquid nitrogen temperatures. This cryopreservation technology was specifically developed to address the immediate need to have secure long-term back-up storage for citrus co...

  3. Integrated Management of Citrus Canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fruit losses due to citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), vary each crop season depending on citrus variety, tree age, flushing condition, leafminer control, and coincidence of weather events with occurrence of susceptible fruit and foliage. In 2012, crop losses in Hamlin f...

  4. Antimicrobial effects of Citrus sinensis peel extracts against dental caries bacteria: An in vitro study

    PubMed Central

    Shetty, Sapna B.; Mahin-Syed-Ismail, Prabu; Varghese, Shaji; Thomas-George, Bibin; Kandathil- Thajuraj, Pathinettam; Baby, Deepak; Haleem, Shaista; Sreedhar, Sreeja

    2016-01-01

    Background Ethnomedicine is gaining admiration since years but still there is abundant medicinal flora which is unrevealed through research. The study was conducted to assess the in vitro antimicrobial potential and also determine the minimum inhibitory concentration (MIC) of Citrus sinensis peel extracts with a view of searching a novel extract as a remedy for dental caries pathogens. Material and Methods Aqueous and ethanol (cold and hot) extracts prepared from peel of Citrus sinensis were screened for in vitro antimicrobial activity against Streptococcus mutans and Lactobacillus acidophilus, using agar well diffusion method. The lowest concentration of every extract considered as the minimal inhibitory concentration (MIC) values were determined for both test organisms. One way ANOVA with Post Hoc Bonferroni test was applied for statistical analysis. Confidence level and level of significance were set at 95% and 5% respectively. Results Dental caries pathogens were inhibited most by hot ethanolic extract of Citrus sinensispeel followed by cold ethanolic extract. Aqueous extracts were effective at very high concentrations. Minimum inhibitory concentration of hot and cold ethanolic extracts of Citrus sinensis peel ranged between 12-15 mg/ml against both the dental caries pathogens. Conclusions Citrus sinensispeels extract was found to be effective against dental caries pathogens and contain compounds with therapeutic potential. Nevertheless, clinical trials on the effect of these plants are essential before advocating large-scale therapy. Key words:Agar well diffusion, antimicrobial activity, dental caries, Streptococcus mutans, Lactobacillus acidophilus. PMID:26855710

  5. 78 FR 63369 - Citrus Canker, Citrus Greening, and Asian Citrus Psyllid; Interstate Movement of Regulated...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

    ... published an interim rule \\1\\ in the Federal Register (76 FR 23449-23459, Docket No. APHIS-2010-0048) that... 7 CFR part 301 that was published at 76 FR 23449-23459 on April 27, 2011, is adopted as a final rule... Animal and Plant Health Inspection Service 7 CFR Part 301 RIN 0579-AD29 Citrus Canker, Citrus...

  6. Mycotoxin production by Alternaria strains isolated from Argentinean wheat.

    PubMed

    Patriarca, A; Azcarate, M P; Terminiello, L; Fernández Pinto, V

    2007-11-01

    The toxigenic potential of Alternaria strains isolated from Argentinean wheat was investigated. A total of 123 strains were assayed for the production of tenuazonic acid (TA), alternariol (AOH) and alternariol monomethyl ether (AME). All but one of the isolates were able to produce at least one of the three mycotoxins. TA was produced by 72% of the strains (1-14782 mg/kg), AOH by 87% (4-622 mg/kg) and AME by 91% (7-2625 mg/kg). The average level of TA detected for all strains (1757 mg/kg) was higher than the average level of both alternariols (162 mg/kg for AOH and 620 mg/kg for AME). TA was the toxin produced at the highest concentration but in lower frequency. Most of the strains were able to synthesize more than one toxin: 74 isolates (60%) were positive for all three toxins, 30 (24%) for both AOH and AME, 5 (4%) for both TA and AME, and 2 (2%) for TA and AOH. The widespread occurrence of Alternaria in wheat and its ability to produce mycotoxins suggests the possible occurrence of its toxins in wheat naturally infected with this fungus. PMID:17804107

  7. Activation of Melanin Synthesis in Alternaria infectoria by Antifungal Drugs

    PubMed Central

    Fernandes, Chantal; Prados-Rosales, Rafael; Silva, Branca M. A.; Nakouzi-Naranjo, Antonio; Zuzarte, Mónica; Chatterjee, Subhasish; Stark, Ruth E.; Casadevall, Arturo

    2015-01-01

    The importance of Alternaria species fungi to human health ranges from their role as etiological agents of serious infections with poor prognoses in immunosuppressed individuals to their association with respiratory allergic diseases. The present work focuses on Alternaria infectoria, which was used as a model organism of the genus, and was designed to unravel melanin production in response to antifungals. After we characterized the pigment produced by A. infectoria, we studied the dynamics of 1,8-dihydroxynaphthalene (DHN)-melanin production during growth, the degree of melanization in response to antifungals, and how melanization affected susceptibility to several classes of therapeutic drugs. We demonstrate that A. infectoria increased melanin deposition in cell walls in response to nikkomycin Z, caspofungin, and itraconazole but not in response to fluconazole or amphotericin B. These results indicate that A. infectoria activates DHN-melanin synthesis in response to certain antifungal drugs, possibly as a protective mechanism against these drugs. Inhibition of DHN-melanin synthesis by pyroquilon resulted in a lower minimum effective concentration (MEC) of caspofungin and enhanced morphological changes (increased hyphal balloon size), characterized by thinner and less organized A. infectoria cell walls. In summary, A. infectoria synthesizes melanin in response to certain antifungal drugs, and its susceptibility is influenced by melanization, suggesting the therapeutic potential of drug combinations that affect melanin synthesis. PMID:26711773

  8. Activation of Melanin Synthesis in Alternaria infectoria by Antifungal Drugs.

    PubMed

    Fernandes, Chantal; Prados-Rosales, Rafael; Silva, Branca M A; Nakouzi-Naranjo, Antonio; Zuzarte, Mónica; Chatterjee, Subhasish; Stark, Ruth E; Casadevall, Arturo; Gonçalves, Teresa

    2016-03-01

    The importance of Alternaria species fungi to human health ranges from their role as etiological agents of serious infections with poor prognoses in immunosuppressed individuals to their association with respiratory allergic diseases. The present work focuses on Alternaria infectoria, which was used as a model organism of the genus, and was designed to unravel melanin production in response to antifungals. After we characterized the pigment produced by A. infectoria, we studied the dynamics of 1,8-dihydroxynaphthalene (DHN)-melanin production during growth, the degree of melanization in response to antifungals, and how melanization affected susceptibility to several classes of therapeutic drugs. We demonstrate that A. infectoria increased melanin deposition in cell walls in response to nikkomycin Z, caspofungin, and itraconazole but not in response to fluconazole or amphotericin B. These results indicate that A. infectoria activates DHN-melanin synthesis in response to certain antifungal drugs, possibly as a protective mechanism against these drugs. Inhibition of DHN-melanin synthesis by pyroquilon resulted in a lower minimum effective concentration (MEC) of caspofungin and enhanced morphological changes (increased hyphal balloon size), characterized by thinner and less organized A. infectoria cell walls. In summary, A. infectoria synthesizes melanin in response to certain antifungal drugs, and its susceptibility is influenced by melanization, suggesting the therapeutic potential of drug combinations that affect melanin synthesis. PMID:26711773

  9. Chemical constituents of marine mangrove-derived endophytic fungus Alternaria tenuissima EN-192

    NASA Astrophysics Data System (ADS)

    Sun, Hong; Gao, Shushan; Li, Xiaoming; Li, Chunshun; Wang, Bingui

    2013-03-01

    A chemical investigation of the ethyl acetate extract of the fermentation broth of Alternaria tenuissima EN-192, an endophytic fungus obtained from the stems of the marine mangrove plant Rhizophora stylosa, resulted in the isolation of nine known secondary metabolites, including four indole-diterpenoids: penijanthine A ( 1), paspaline ( 2), paspalinine ( 3), and penitrem A ( 4); three tricycloalternarene derivatives: tricycloalternarene 3a ( 5), tricycloalternarene 1b ( 6), and tricycloalternarene 2b ( 7); and two alternariol congeners: djalonensone ( 8) and alternariol ( 9). The chemical structures of these metabolites were characterized through a combination of detailed spectroscopic analyses and their comparison with reports from the literature. The inhibitory activities of each isolated compound against four bacteria were evaluated and compounds 5 and 8 displayed moderate activity against the aquaculture pathogenic bacterium Vibrio anguillarum, with inhibition zone diameters of 8 and 9 mm, respectively, at 100 μg/disk. To the best of our knowledge, this is the first report on the secondary metabolites of mangrove-derived A lternaria tenuissima and also the first report of the isolation of indole-diterpenoids from fungal genus A lternaria.

  10. Ultrastructure of the salivary glands, alimentary canal and bacteria-like organisms in the Asian citrus psyllid, vector of citrus huanglongbing-disease bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several psyllids (Hemiptera: Psylloidea) are known as vectors of some economically important viral and bacterial plant pathogens. The Asian citrus psyllid (ACP, Diaphorina citri, Hemiptera, Liviidae) is the principal vector of ‘Candidatus Liberibacter asiaticus’ (Las), the putative bacterial causal ...

  11. SCREENING CITRUS GERMPLASM FOR RESISTANCE TO XANTHOMONAS ANONOPODIS PV. CITRI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus bacterial canker (causal agent Xanthomonas axonopodis pv. citri (Xac)) is a serious threat to the citrus industry. Currently there are no effective means to control citrus canker. Our objective was to determine the resistance of selected Citrus species, citrus hybrids, and citrus relatives to...

  12. Application of ultraviolet-C light on oranges for the inactivation of postharvest wound pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Germicidal effects of ultraviolet-C (UV-C) light on the postharvest wound pathogens of citrus fruits namely Penicillium digitatum and Penicillium italicum were investigated. P. digitatum and P. italicum spores were inoculated (4.00 – 4.50 log cfu/ orange) onto Washington navel oranges (Citrus sinens...

  13. Increased detection sensitivity of HLB pathogen by targeting a multi-copy gene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB, yellow shoot disease) is a highly destructive disease in citrus production worldwide. “Candidatus Liberibacter asiaticus” is the pathogen of HLB based on strong evidence linking this bacterium with the disease. A single incidence of HLB has been reported in California. Alt...

  14. Characterization of a Proposed Dichorhavirus Associated with the Citrus Leprosis Disease and Analysis of the Host Response

    PubMed Central

    Cruz-Jaramillo, José Luis; Ruiz-Medrano, Roberto; Rojas-Morales, Lourdes; López-Buenfil, José Abel; Morales-Galván, Oscar; Chavarín-Palacio, Claudio; Ramírez-Pool, José Abrahán; Xoconostle-Cázares, Beatriz

    2014-01-01

    The causal agents of Citrus leprosis are viruses; however, extant diagnostic methods to identify them have failed to detect known viruses in orange, mandarin, lime and bitter orange trees with severe leprosis symptoms in Mexico, an important citrus producer. Using high throughput sequencing, a virus associated with citrus leprosis was identified, belonging to the proposed Dichorhavirus genus. The virus was termed Citrus Necrotic Spot Virus (CNSV) and contains two negative-strand RNA components; virions accumulate in the cytoplasm and are associated with plasmodesmata—channels interconnecting neighboring cells—suggesting a mode of spread within the plant. The present study provides insights into the nature of this pathogen and the corresponding plant response, which is likely similar to other pathogens that do not spread systemically in plants. PMID:25004279

  15. Characterization of the Relative Abundance of the Citrus Pathogen Ca. Liberibacter Asiaticus in the Microbiome of Its Insect Vector, Diaphorina citri, using High Throughput 16S rRNA Sequencing

    PubMed Central

    Fagen, Jennie R; Giongo, Adriana; Brown, Christopher T; Davis-Richardson, Austin G; Gano, Kelsey A; Triplett, Eric W

    2012-01-01

    The relationship between the causal agent of Huanglongbing (HLB), Ca. Liberibacter asiaticus(Las), and the naturally occurring endosymbiotic community of its insect vector, the Asian citrus psyllid (ACP), Diaphorina citri, was studied. Variation was observed in the titer of Las within an ACP population feeding on the same material. The cause of this disparity is unknown, and has implications for Las transmission and the spread of HLB. This study utilizes culture independent methods to establish the relationship between the ACP’s microbial community and Las acquisition. DNA from 21 psyllids was amplified using universal 16S rRNA primers with Illumina adaptor regions and a sample-specific 7- base identifier. These amplicons were then batch-sequenced on the Illumina platform. The resulting sequences were separated by the identifier, and compared to known sequences in a 16S rRNA database. The microbial communities of each psyllid were compared to determine whether a correlation exists between the ACP’s endosymbionts and level of Las acquisition. ACPs were dominated by the same four bacterialgenera regardless of the abundance of Ca.Liberibacter. A combination of qPCR and Illumina sequencing was used to establish an infection gradient among the sampled ACPs. The Ca. Liberibacter titer within the insect was found to have a strong negative relationship with an endosymbiont residing in the syncytium of the mycetocyte and a positive relationship with Wolbachia. These correlations have implications in the acquisition of Las by the ACP as well as the activities of Las within this vector. PMID:22529882

  16. Antimicrobial activity of commercial citrus-based natural extracts against Escherichia coli O157:H7 isolates and mutant strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to increasing concerns about the development of antimicrobial resistance amongst pathogenic bacteria, alternative strategies have been sought that do not use antibiotics to reduce pathogenic bacteria from foods and patients. A natural compound that has potent antimicrobial properties is citrus ...

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

    PubMed

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

    2015-05-01

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

  18. Sequencing the Major Mycosphaerella Pathogens of Wheat and Banana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycosphaerella is one of the largest genera of plant pathogenic fungi with more than 1,000 named species, many of which are important pathogens causing leaf spotting diseases in a wide variety of crops including cereals, citrus, banana, eucalypts, soft fruits, and horticultural crops. A few species ...

  19. Past and future of a century old Citrus Tristeza Virus collection: A California citrus germplasm tale

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The California Citrus Clonal Protection Program (CCPP), Riverside, CA provides a mechanism for introduction and distribution of citrus germplasm from any citrus-growing area of the world to California for use in research, variety improvement, or by industry. Citrus tristeza virus (CTV) is a serious ...

  20. Exacerbation of citrus canker by citrus leafminer, Phyllocnistis citrella in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (caused by Xanthomonas citri subsp. citri, Xcc) is an important bacterial disease of citrus that is spread naturally by rain and wind. Damage to citrus leaves by the citrus leafminer (CLM) , Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), has been shown to promote infect...

  1. Citrus Grove Mapping

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Citrus growers have long used aerial photography to inventory the number of groves in production. A new development at Kennedy Space Center, aerial mapping of groves with color infrared (CIR) film, affords an important advance in grove management by detecting and locating unhealthy trees long before they could be detected by ground survey methods. Aerial CIR photography picks up light reflected from foliage-- light not visible to the human eye--and enables differentiation between healthy and "stressed" (diseased) trees of a Florida orange/grapefruit grove. Computer aided photo interpretation techniques permit grading diseased trees lightly, moderately or severely stressed or dead. Method of grove mapping has offered advantage to growers in early disease warning, possible savings through water regulation and provision of a permanent record of grove growth patterns.

  2. Microbes Associated with Freshly Prepared Juices of Citrus and Carrots

    PubMed Central

    Aneja, Kamal Rai; Dhiman, Romika; Aggarwal, Neeraj Kumar; Kumar, Vikas; Kaur, Manpreeet

    2014-01-01

    Fruit juices are popular drinks as they contain antioxidants, vitamins, and minerals that are essential for human being and play important role in the prevention of heart diseases, cancer, and diabetes. They contain essential nutrients which support the growth of acid tolerant bacteria, yeasts, and moulds. In the present study, we have conducted a microbiological examination of freshly prepared juices (sweet lime, orange, and carrot) by serial dilution agar plate technique. A total of 30 juice samples were examined for their microbiological quality. Twenty-five microbial species including 9 bacterial isolates, 5 yeast isolates, and 11 mould isolates were isolated from juices. Yeasts and moulds were the main cause of spoilage of juices. Aspergillus flavus and Rhodotorula mucilaginosa were observed in the maximum number of juice samples. Among bacteria Bacillus cereus and Serratia were dominant. Escherichia coli and Staphylococcus aureus were detected in few samples. Candida sp., Curvularia, Colletotrichum, and Acetobacter were observed only in citrus juice samples. Alternaria, Aspergillus terreus, A. niger, Cladosporium, and Fusarium were also observed in tested juice samples. Some of the microorganisms detected in these juice samples can cause disease in human beings, so there is need for some guidelines that can improve the quality of fruit juices. PMID:26904628

  3. Phytochemical, antimicrobial, and antioxidant activities of different citrus juice concentrates.

    PubMed

    Oikeh, Ehigbai I; Omoregie, Ehimwenma S; Oviasogie, Faith E; Oriakhi, Kelly

    2016-01-01

    The search for new antimicrobial compounds is ongoing. Its importance cannot be overemphasized in an era of emerging resistant pathogenic organisms. This study therefore investigated the phytochemical composition and antioxidant and antimicrobial activities of different citrus juice concentrates. Fruit juices of Citrus tangerine (tangerine), Citrus paradisi (grape), Citrus limon (lemon), and Citrus aurantifolia (lime) were evaluated. Antimicrobial activities against five bacterial and three fungal strains were evaluated. The results revealed the presence of alkaloids, flavonoids, steroids, terpenoids, saponins, cardiac glycosides, and reducing sugars in all the juice concentrates. DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging capacities varied with tangerine and grape juices having better scavenging capacities than lemon and lime juices. Grape juice was observed to have a significantly higher (P < 0.05) ferric-reducing antioxidant potential (FRAP) value (364.2 ± 10.25 μmol/L Fe(II)/g of the extract) than the reference antioxidant, ascorbic acid (312.88 ± 5.61 μmol/L). Antimicrobial studies revealed differential antimicrobial activities against different microbial strains. Zones of inhibition ranging from 4 to 26 mm were observed for the antibacterial tests with 0-24 mm for antifungal test. Minimum inhibitory concentrations (MIC) and minimum bacteriostatic concentrations (MBC) for concentrates against bacterial strains ranged from 12.5 to 200 μg/mL. Lemon and lime juice concentrates had lower MIC and MBC values with orange and tangerine having the highest values. Minimum fungicidal concentrations ranged from 50 to 200 μg/mL. The results of this study suggest that these juice concentrates may have beneficial antimicrobial roles that can be exploited in controlling unwanted microbial growth. PMID:26788316

  4. Citrus Canker and Citrus Huanglongbing, Two Exotic Bacterial Diseases Threatening the Citrus Industries of the Western Hemisphere

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two exotic Asian bacterial diseases of citrus are currently plaguing citrus industries in the Western Hemisphere. The two largest citrus producing areas in the Americas, located in Florida and the state of São Paulo Brazil, are presently battling these devastating diseases. The presence of these d...

  5. Control of virus diseases of citrus.

    PubMed

    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. PMID:25591879

  6. Development and validation of a multiplex reverse transcription quantitative PCR (RT-qPCR) assay for the rapid detection of Citrus tristeza virus, Citrus psorosis virus, and Citrus leaf blotch virus.

    PubMed

    Osman, Fatima; Hodzic, Emir; Kwon, Sun-Jung; Wang, Jinbo; Vidalakis, Georgios

    2015-08-01

    A single real-time multiplex reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay for the simultaneous detection of Citrus tristeza virus (CTV), Citrus psorosis virus (CPsV), and Citrus leaf blotch virus (CLBV) was developed and validated using three different fluorescently labeled minor groove binding qPCR probes. To increase the detection reliability, coat protein (CP) genes from large number of different isolates of CTV, CPsV and CLBV were sequenced and a multiple sequence alignment was generated with corresponding CP sequences from the GenBank and a robust multiplex RT-qPCR assay was designed. The capacity of the multiplex RT-qPCR assay in detecting the viruses was compared to singleplex RT-qPCR designed specifically for each virus and was assessed using multiple virus isolates from diverse geographical regions and citrus species as well as graft-inoculated citrus plants infected with various combination of the three viruses. No significant difference in detection limits was found and specificity was not affected by the inclusion of the three assays in a multiplex RT-qPCR reaction. Comparison of the viral load for each virus using singleplex and multiplex RT-qPCR assays, revealed no significant differences between the two assays in virus detection. No significant difference in Cq values was detected when using one-step and two-step multiplex RT-qPCR detection formats. Optimizing the RNA extraction technique for citrus tissues and testing the quality of the extracted RNA using RT-qPCR targeting the cytochrome oxidase citrus gene as an RNA specific internal control proved to generate better diagnostic assays. Results showed that the developed multiplex RT-qPCR can streamline viruses testing of citrus nursery stock by replacing three separate singleplex assays, thus reducing time and labor while retaining the same sensitivity and specificity. The three targeted RNA viruses are regulated pathogens for California's mandatory "Section 3701

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  8. Potassium sorbate residue levels and persistence in citrus fruit as detected by a simple colorimetric method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Postharvest applications of potassium sorbate (PS) to fresh citrus fruit control fungal decay pathogens, such as Penicillium digitatum, cause of green mold. Although PS effectiveness has been examined repeatedly, little is known about PS residues. A colorimetric method that employed extraction of th...

  9. Validation and comparison of a hierarchal sampling plan for estimating incidence of citrus stubborn disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus stubborn disease (CSD) is a production-limiting disease that is caused by Spiroplasma citri, a culturable wall-less prokaryote. The pathogen is transmitted mainly by the beet leafhopper (BLH) in California. The objective of this study was to validate a method to estimate incidence of CSD in...

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

    PubMed

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

    2014-12-01

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

  11. Citrus tristeza virus-host interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 s...

  12. Huanglongbing: a devastating disease of citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus greening or Huanglongbing (HLB) disease is devastating the citrus industry worldwide, from Asia to the Americas. The only major citrus regions free of this disease are the Mediterranean and Australia/New Zealand. To date there is no cure, no resistance and no therapy for HLB and production ra...

  13. Citrus tristeza virus-aphid interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A review chapter on aphid transmission of Citrus tristeza virus is provided for a book on “Vector-Mediated Transmission of Plant Pathogens”. Earliest uses of citrus goes back over two millennia as items of trade, gifts and medicinal compounds. Citrus propagation during this period was by seed and si...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  15. Systemic jasmonic acid modulation in mycorrhizal tomato plants and its role in induced resistance against Alternaria alternata.

    PubMed

    Nair, A; Kolet, S P; Thulasiram, H V; Bhargava, S

    2015-05-01

    Tomato plants colonised with the arbuscular mycorrhizal (AM) fungus Glomus fasciculatum show systemic induced resistance to the foliar pathogen Alternaria alternata, as observed in interactions of other AM-colonised plants with a range of pathogens. The role of jasmonic (JA) and salicylic (SA) acid in expression of this mycorrhiza-induced resistance (MIR) against A. alternata was studied by measuring: (i) activity of enzymes reported to be involved in their biosynthesis, namely lipoxygenase (LOX) and phenylammonia lyase (PAL); and (ii) levels of methyl jasmonate (MeJA) and SA. Transcript abundance of some defence genes associated with JA and SA response pathways were also studied. Both LOX and PAL activity increased twofold in response to pathogen application to control plants. AM-colonised plants had three-fold higher LOX activity compared to control plants, but unlike controls, this did not increase further in response to pathogen application. Higher LOX activity in AM-colonised plants correlated with four-fold higher MeJA in leaves of AM-colonised plants compared to controls. Treatment of plants with the JA biosynthesis inhibitor salicylhydroxamic acid (SHAM) led to 50% lower MeJA in both control and AM-colonised plants and correlated with increased susceptibility to A. alternata, suggesting a causal role for JA in expression of MIR against the pathogen. Genes involved in JA biosynthesis (OPR3) and response (COI1) showed six- and 42-fold higher expression, respectively, in leaves of AM-colonised plants compared to controls. AM-colonised plants also showed increased expression of the SA response gene PR1 and that of the wound-inducible polypeptide prosystemin. Our results suggest that the systemic increase in JA in response to AM colonisation plays a key role in expression of MIR against A. alternata. PMID:25327848

  16. [The importance of genus Alternaria in mycotoxins production and human diseases].

    PubMed

    Pavón Moreno, M Á; González Alonso, I; Martín de Santos, R; García Lacarra, T

    2012-01-01

    Alternaría is a cosmopolitan fungal genus that includes saprophytic, endophytic and pathogenic species, widely distributed in soil and organic matter in decomposition. Plant pathogenic species affect cereals, vegetables and fruit crops in the field and during storage. Alternaría spp. contamination is responsible for some of the world's most devastating plant diseases, causing serious reduction of crop yields and considerable economic losses. Alternaría species produce more than 70 secondary metabolites which are toxic to plants, and some of these phytotoxins have been chemically characterised and reported to act as mycotoxins to humans and animals. Exposure to Alternaría spp. toxins has been linked to a variety of adverse effects on human and animal health, including genotoxic, mutagenic, carcinogenic and cytotoxic effects. Alternaría spp. mycotoxins have been isolated from fruits (apple, pear, melon, apricot, grapes, raisins, strawberry, olive, citrus fruits and dried figs), vegetables (tomato, pepper and carrot) and tubers (potato), as well as from several processed foodstuffs manufactured with damaged raw materials (juices, preserves, sauces, etc.). Moreover, Alternaría spp. are frequently associated with allergic reactions in sensitized individuals. PMID:23588425

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

    PubMed

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

    2008-08-01

    Xylella fastidiosa (Wells, Raju, Hung, Weisburg, Mandelco-Paul, and Brenner) is a bacterial pathogen transmitted by several sharpshooters in two tribes of Cicadellinae (Proconiini and Cicadellini). Here, we compared the transmission efficiency of X. fastidiosa in coffee (Coffea arabica L.) and citrus [Citrus sinensis (L.) Osbeck] by Cicadellini [Bucephalogonia xanthophis (Berg) and Dilobopterus costalimai Young] and Proconiini [Homalodisca ignorata Melichar and Oncometopia facialis (Signoret)] sharpshooters that occur in both crops. At different seasons, healthy adults of each species were submitted to a 48-h acquisition access period on citrus or coffee source plants infected with X. fastidiosa isolates that cause Citrus variegated chlorosis (CVC) and Coffee leaf scorch (CLS), respectively, and then confined on healthy seedlings of the corresponding host plant for a 48-h inoculation access period. No significant effect of inoculation season was observed when comparing infection rates of citrus or coffee plants inoculated by vectors at different times of the year. In citrus, the transmission rate by single insects was significantly higher for H. ignorata (30%) in relation to B. xanthophis (5%) and O. facialis (1.1%), but there was no difference among vector species in coffee, whose transmission rates ranged from 1.2 to 7.2%. Comparing host plants, H. ignorata was more effective in transmitting X. fastidiosa to citrus (30%) in relation to coffee (2.2%), whereas the other vectors transmitted the bacterium to both hosts with similar efficiencies. Despite these variations, vector efficiency in coffee and citrus is lower than that reported in other hosts. PMID:18767717

  18. Dustborne Alternaria alternata antigens in U.S. homes: Results from the National Survey of Lead and Allergens in Housing

    PubMed Central

    Salo, Päivi M.; Yin, Ming; Arbes, Samuel J.; Cohn, Richard D.; Sever, Michelle; Muilenberg, Michael; Burge, Harriet A.; London, Stephanie J.; Zeldin, Darryl C.

    2005-01-01

    Background: Alternaria alternata is one of the most common fungi associated with allergic disease. However, Alternaria exposure in indoor environments is not well characterized. Objective: The primary goals of this study were to examine the prevalence of Alternaria exposure and identify independent predictors of Alternaria antigen concentrations in U.S. homes. Methods: Data for this cross-sectional study were obtained from the National Survey of Lead and Allergens in Housing. A nationally representative sample of 831 housing units in 75 different locations throughout the U.S. completed the survey. Information on housing and household characteristics was obtained by questionnaire and environmental assessments. Concentrations of Alternaria antigens in dust collected from various indoor sites were assessed with a polyclonal anti-Alternaria antibody assay. Results: Alternaria antigens were detected in most (95-99%) of the dust samples. The geometric mean concentration, reflecting the average Alternaria concentration in homes, was 4.88 μg/g (SE=0.13 μg/g). In the multivariable linear regression analysis, the age of the housing unit, geographic region, urbanization, poverty, family race, observed mold and moisture problems, use of dehumidifier, and presence of cats and dogs were independent predictors of Alternaria antigen concentrations. Less frequent cleaning and smoking indoors also contributed to higher Alternaria antigen levels in homes. Conclusion: Exposure to Alternaria alternata antigens in U.S. homes is common. Antigen levels in homes are not only influenced by regional factors but also by residential characteristics. Preventing mold and moisture problems, avoiding smoking indoors, and regular household cleaning may help reduce exposure to Alternaria antigens indoors. PMID:16159634

  19. Characterization of Alternaria strains from Argentinean blueberry, tomato, walnut and wheat.

    PubMed

    Andersen, Birgitte; Nielsen, Kristian F; Fernández Pinto, Virginia; Patriarca, Andrea

    2015-03-01

    Alternaria species have the ability to produce a variety of secondary metabolite, which plays important roles in food safety. Argentina is the second largest exporter of fresh and processed food products to Europe, however, few studies on Alternaria mycotoxins and other bioactive secondary metabolites have been carried out on Argentinean cereals, fruit and vegetables. Knowing the full chemical potential and the distribution of Alternaria spp. on crops, it is necessary to establish a toxicological risk assessment for food products for human consumption. In the present study, 87 Alternaria strains from different substrates (tomato, wheat, blueberries and walnuts) were characterized according to morphology and metabolite production. Aggressive dereplication (accurate mass, isotopic patterns and lists of all described compounds from Alternaria) was used for high-throughput evaluation of the chemical potential. Four strains belonged to the Alternaria infectoria sp.-grp., 6 to the Alternaria arborescens sp.-grp., 6 showed a sporulation pattern similar to that of "M" according to Simmons, 1 to that of Alternaria vaccinii, and the remaining 70 constituted a diverse group belonging to morphological groups "G" and "H". The cluster analysis yielded 16 almost identical dendrograms and grouped the Alternaria strains into four clusters and 11 singletons and outlier groups. The chemical analysis showed that AOH and AME were the most common metabolites produced, followed by TEN, ALXs and TeA. The A. infectoria sp.-grp. had no metabolites in common with the rest of the strains. Several secondary metabolites isolated from large-spored Alternaria species or other fungal genera were detected, such as dehydrocurvularin, pyrenochaetic acid and alternarienonic acid. The strains isolated from tomato produced lower amounts of metabolites than strains from blueberries, walnut and wheat, although individual strains from tomato produced the highest amount of some metabolites. The A

  20. Isotope fractionation of selenium during fungal biomethylation by Alternaria alternata.

    PubMed

    Schilling, Kathrin; Johnson, Thomas M; Wilcke, Wolfgang

    2011-04-01

    The natural abundance of stable Se isotopes may reflect sources and formation conditions of methylated Se. We aimed at (1) quantifying the degree of methylation of selenate [Se(VI)] and (hydro)selenite [Se(IV)] by the fungus Alternaria alternata at pH 4 and 7 and (2) determining the effects of these different Se sources and pH values on 82Se/76Se ratios (δ82/76Se) in methylselenides. Alternaria alternata was incubated with Se(VI) and Se(IV) in closed microcosms for 11-15 days and additionally with Se(IV) for 3-5 days at 30 °C. We determined Se concentrations and δ82/76Se values in source Se(VI) and Se(IV), media, fungi, and trapped methylselenides. In Se(VI) incubations, methylselenide volatilization ended before the 11th day, and the amounts of trapped methylselenide were not significantly different among the 11-15 day incubations. In 11-15 days, 2.9-11% of Se(VI) and 21-29% of Se(IV) were methylated, and in 3-5 days, 3-5% of Se(IV) was methylated. The initial δ82/76Se values of Se(VI) and Se(IV) were -0.69±SD 0.07‰, and -0.20±0.05‰, respectively. The δ82/76Se values of methylselenides differed significantly between Se(VI) (-3.97‰ to -3.25‰) and Se(IV) (-1.44‰ to -0.16‰) as sources after 11-15 days of incubation; pH had little influence on δ82/76Se values. Thus, the δ82/76Se values of methylselenide indicate the source species of methylselenides used in this study. The strong isotope fractionation of Se(VI) is probably attributable to the different reduction steps of Se(VI) to Se(-II) which were rate-limiting explaining the low methylation yields, but not to the methylation itself. The shorter incubation of Se(IV) for 3-5 days showed a large Se isotope fractionation of at least -6‰ before the biomethylation reaction reached its end. This initial Se isotope fractionation during methylation of Se(IV) is much larger than previously published. PMID:21366259

  1. Transcription Factor Amr1 Induces Melanin Biosynthesis and Suppresses Virulence in Alternaria brassicicola

    SciTech Connect

    Cho, Yangrae; Srivastava, Akhil; Ohm, Robin A.; Lawrence, Christopher B.; Wang, Koon-Hui; Grigoriev, Igor V.; Marahatta, Sharadchandra P.

    2012-05-01

    Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. Several A. brassicicola genes have been characterized as affecting pathogenesis of Brassica species. To study regulatory mechanisms of pathogenesis, we mined 421 genes in silico encoding putative transcription factors in a machine-annotated, draft genome sequence of A. brassicicola. In this study, targeted gene disruption mutants for 117 of the transcription factor genes were produced and screened. Three of these genes were associated with pathogenesis. Disruption mutants of one gene (AbPacC) were nonpathogenic and another gene (AbVf8) caused lesions less than half the diameter of wild-type lesions. Unexpectedly, mutants of the third gene, Amr1, caused lesions with a two-fold larger diameter than the wild type and complementation mutants. Amr1 is a homolog of Cmr1, a transcription factor that regulates melanin biosynthesis in several fungi. We created gene deletion mutants of ?amr1 and characterized their phenotypes. The ?amr1 mutants used pectin as a carbon source more efficiently than the wild type, were melanin-deficient, and more sensitive to UV light and glucanase digestion. The AMR1 protein was localized in the nuclei of hyphae and in highly melanized conidia during the late stage of plant pathogenesis. RNA-seq analysis revealed that three genes in the melanin biosynthesis pathway, along with the deleted Amr1 gene, were expressed at low levels in the mutants. In contrast, many hydrolytic enzyme-coding genes were expressed at higher levels in the mutants than in the wild type during pathogenesis. The results of this study suggested that a gene important for survival in nature negatively affected virulence, probably by a less efficient use of plant cell-wall materials. We speculate that the functions of the Amr1 gene are important to the success of A. brassicicola as a competitive saprophyte and plant parasite.

  2. Citrus Tissue Culture

    PubMed Central

    Einset, John W.

    1978-01-01

    In vitro growth of explant (juice vesicle or albedo tissues) cultures from citron (Citrus medica), lemon (C. limon), grapefruit (C. paradisi), sweet orange (C. sinensis), and mandarin (C. reticulata) fruits was stimulated by addition of orange juice (10% v/v optimum) to a basal medium containing Murashige and Skoog salts, 50 grams per liter sucrose, 100 milligrams per liter myo-inositol, 5 milligrams per liter thiamine·HCl, 2 milligrams per liter 2,4-dichlorophenoxyacetic acid and 0.5 milligrams per liter kinetin. In analyzing this effect of orange juice on citron explant cultures, we failed to obtain increased yields by addition of appropriate concentrations of citric acid to the basal medium but obtained growth stimulation when the medium was supplemented with juice from an “acidless” orange variety (cv. Lima). These facts suggest that some component(s) other than citric acid is involved. Addition of the inorganic ash corresponding to 10% (v/v) orange juice to the basal medium had no effect on yields. Similarly, the stimulatory effect of orange juice could not be explained based on its content of sucrose or of organic growth factors already present in the basal medium. ImagesFig. 2 PMID:16660631

  3. Bud emergence and shoot growth from mature citrus nodal segments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bud emergence and shoot growth from adult phase citrus nodal cultures were studied using Citrus mitis (calamondin), Citrus paradisi (grapefruit), and Citrus sinensis (sweet orange). The effects of 6-benzylaminopurine (BA), indole 3-acetic acid (IAA), and citrus type on shoot quality and growth fro...

  4. Alternaria infections: laboratory diagnosis and relevant clinical features.

    PubMed

    Pastor, F J; Guarro, J

    2008-08-01

    The genus Alternaria contains several species of melanized hyphomycetes that cause opportunistic human infections. The published literature contains 210 reported cases of human alternarioses between 1933 and the present day. The most frequent clinical manifestations are cutaneous and subcutaneous infections (74.3%), followed by oculomycosis (9.5%), invasive and non-invasive rhinosinusitis (8.1%) and onychomycosis (8.1%). Immunosuppression is frequently associated with cutaneous and subcutaneous infections and rhinosinusitis. The most important risk factors for cutaneous and subcutaneous infections are solid organ transplantation and Cushing's syndrome, and those for rhinosinusitis are bone marrow transplants. Having been exposed to soil and garbage is common in all cases of oculomycosis, with corticotherapy being a risk factor in 50% of these cases. Previous contact with soil and/or trauma to the nails is associated with most cases of onychomycosis. In general, alternariosis shows a good response to conventional antifungal drugs. On some occasions, steroid suppression or reduction is sufficient to resolve an infection. Itraconazole is the antifungal drug used most frequently to successfully treat onychomycosis and cutaneous and subcutaneous infections. Posaconazole and voriconazole are promising therapeutic options, with the latter being especially so for oculomycosis. PMID:18727797

  5. Dehydrin-like Proteins in the Necrotrophic Fungus Alternaria brassicicola Have a Role in Plant Pathogenesis and Stress Response

    PubMed Central

    Pochon, Stéphanie; Simoneau, Philippe; Pigné, Sandrine; Balidas, Samuel; Bataillé-Simoneau, Nelly; Campion, Claire; Jaspard, Emmanuel; Calmes, Benoît; Hamon, Bruno; Berruyer, Romain; Juchaux, Marjorie; Guillemette, Thomas

    2013-01-01

    In this study, the roles of fungal dehydrin-like proteins in pathogenicity and protection against environmental stresses were investigated in the necrotrophic seed-borne fungus Alternaria brassicicola. Three proteins (called AbDhn1, AbDhn2 and AbDhn3), harbouring the asparagine-proline-arginine (DPR) signature pattern and sharing the characteristic features of fungal dehydrin-like proteins, were identified in the A. brassicicola genome. The expression of these genes was induced in response to various stresses and found to be regulated by the AbHog1 mitogen-activated protein kinase (MAPK) pathway. A knock-out approach showed that dehydrin-like proteins have an impact mainly on oxidative stress tolerance and on conidial survival upon exposure to high and freezing temperatures. The subcellular localization revealed that AbDhn1 and AbDhn2 were associated with peroxisomes, which is consistent with a possible perturbation of protective mechanisms to counteract oxidative stress and maintain the redox balance in AbDhn mutants. Finally, we show that the double deletion mutant ΔΔabdhn1-abdhn2 was highly compromised in its pathogenicity. By comparison to the wild-type, this mutant exhibited lower aggressiveness on B. oleracea leaves and a reduced capacity to be transmitted to Arabidopsis seeds via siliques. The double mutant was also affected with respect to conidiation, another crucial step in the epidemiology of the disease. PMID:24098369

  6. The relationship between PthA expression and the pathogenicity of Xanthomonas axonopodis pv. citri.

    PubMed

    Li, Na; Huang, Long; Liu, Liping; Li, Dazhi; Dai, Suming; Deng, Ziniu

    2014-02-01

    Citrus canker disease, caused by Xanthomonas axonopodis pv. citri, affects almost all citrus species and cultivars and hascaused severe damage to the citrus industry worldwide. PthA is considered the main pathogenesis effector of the pathogen. This research aimed to temporally and spatially analyze the expression of the PthA protein of the bactrium during its culture, and then try to understand the relationship between the PthA expression levels and the pathogenicity. The relationship between the expression of PthA and the pathogenicity of X. axonopodis pv. citri was fully investigated by using SDS-PAGE, Western blot, ELISA and field inoculation, It was found that bacteria cultured for 36 h had the highest expression of PthA and showed the most virulent pathogenicity. The conservation duration of the pathogen isolates influenced their PthA expression and the pathogenicity, and negative relationship between the duration and the expression of PthA and pathogenicity. When the stored pathogen bacteria were cultured in liquid LB medium, they were able to regain activated, showing higher PthA expression level and enhanced pathogenicity, even though the activity was inferior, in terms of both PthA expression and pathogenicity, than the freshly isolated ones. Seven isolates from different citrus orchards displayed almost identical protein expression profiles. It could conclude that the expressions of PthA was positively related to pathogenicity. PMID:24385299

  7. Isolation and characterization of the grain mold fungi, Cochliobolus and Alternaria spp., from sorghum using semi-selective media and DNA sequence analyses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mold diseases, caused by fungal complexes including Alternaria, Cochliobolus and Fusarium species, limit sorghum grain production. Media were tested by plating Fusarium thapsinum, Alternaria sp. and Curvularia lunata, individually and competitively. Dichloran chloramphenicol rose bengal (DRBC) and m...

  8. Site Plan & Site Section of Citrus Landscape (Showing Relationship ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Site Plan & Site Section of Citrus Landscape (Showing Relationship of Victoria Avenue to Citrus Groves) - Arlington Heights Citrus Landscape, Southwestern portion of city of Riverside, Riverside, Riverside County, CA

  9. Chipping citrus wood for gasification

    SciTech Connect

    Churchill, D.B.; Hedden, S.L.; Whitney, J.D.; Shaw, L.N.

    1985-01-01

    Non-productive citrus trees were chipped with a portable fly-wheel-type chipper powered by a 45 kW engine. Chips were air dried under an open shed to 14% (w.b.) moisture content. By weight, approximately 50% of the total tree could be made into usable chips. The root system averaged 36% of the total tree weight.

  10. The effect of Pseudomonas fluorescens strain q2-87 in pathogen inhibition and growth promotion of slash pine seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas fluorescens strain Q2-87 showed significant antagonistic activity against the damping-off pathogens of slash pine (Pinus elliottii), including Rhizoctonia solani, Alternaria alternata and Fusarium oxysporum. In vitro assays showed that strain Q2-87, which has an inhibition index higher t...

  11. Rapid differentiation of citrus Hop stunt viroid variants by use of real-time RT-PCR and high resolution melting analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The RNA genome of Hop stunt viroid (HSVd) contains five to six nucleotides in a variable (V) domain, called the cachexia expression motif, which is associated with pathogenic and non-pathogenic variants in citrus. Current methods to differentiate HSVd variants rely on lengthy greenhouse biological i...

  12. Possible role of plant volatiles in tolerance against huanglongbing in citrus

    PubMed Central

    Hijaz, Faraj; Nehela, Yasser; Killiny, Nabil

    2016-01-01

    abstract Volatile organic compounds (VOC) play an important role in protecting plants from insect and pathogen attack. In this study, we investigated the leaf volatile profiles of 14 citrus varieties. The VOC in citrus leaves were extracted with n-hexane and analyzed using gas chromatography-mass spectrometry (GC-MS). Overall, 4six volatile compounds were identified in the n-hexane extract from citrus leaves. Most of the detected compounds belonged to 3 main groups (monoterpenes, sesquiterpenes, and aliphatic aldehydes). Principle component analysis was used to examine the relative distribution of the studied varieties to each other. Interestingly, volatile profiles of varieties that are tolerant to Candidatus Liberibacter asiaticus (CLas) were different from those of the susceptible ones. Tolerant and moderately-tolerant cultivars contained relatively higher amounts of volatiles than susceptible varieties. In addition, tolerant varieties were also higher in specific compounds which are known for their antimicrobial activities. These compounds include Aldehydes (undecanal, neral, geranial, and citronellal) and some monoterpenes such as linalool, d-limonene, myrcene, α- and β- phellandrene. In addition, some sesquiterpene compounds including t-caryophellene, γ-elemene, β-elemene, germacrene D, and geranyl acetate were higher in tolerant and moderately tolerant cultivars. Severinia buxifolia which is known for its tolerance to CLas and many other pathogens contained higher levels of santalenes and coumarins. Our results indicated that citrus leaf volatiles might play a role in citrus tolerance to CLas. The results of this study may help in understanding of the mechanism of citrus tolerance against CLas. PMID:26829496

  13. Possible role of plant volatiles in tolerance against huanglongbing in citrus.

    PubMed

    Hijaz, Faraj; Nehela, Yasser; Killiny, Nabil

    2016-03-01

    Volatile organic compounds (VOC) play an important role in protecting plants from insect and pathogen attack. In this study, we investigated the leaf volatile profiles of 14 citrus varieties. The VOC in citrus leaves were extracted with n-hexane and analyzed using gas chromatography-mass spectrometry (GC-MS). Overall, 4six volatile compounds were identified in the n-hexane extract from citrus leaves. Most of the detected compounds belonged to 3 main groups (monoterpenes, sesquiterpenes, and aliphatic aldehydes). Principle component analysis was used to examine the relative distribution of the studied varieties to each other. Interestingly, volatile profiles of varieties that are tolerant to Candidatus Liberibacter asiaticus (CLas) were different from those of the susceptible ones. Tolerant and moderately-tolerant cultivars contained relatively higher amounts of volatiles than susceptible varieties. In addition, tolerant varieties were also higher in specific compounds which are known for their antimicrobial activities. These compounds include Aldehydes (undecanal, neral, geranial, and citronellal) and some monoterpenes such as linalool, d-limonene, myrcene, α- and β- phellandrene. In addition, some sesquiterpene compounds including t-caryophellene, γ-elemene, β-elemene, germacrene D, and geranyl acetate were higher in tolerant and moderately tolerant cultivars. Severinia buxifolia which is known for its tolerance to CLas and many other pathogens contained higher levels of santalenes and coumarins. Our results indicated that citrus leaf volatiles might play a role in citrus tolerance to CLas. The results of this study may help in understanding of the mechanism of citrus tolerance against CLas. PMID:26829496

  14. Development of a full-genome cDNA clone of Citrus leaf blotch virus and infection of citrus plants.

    PubMed

    Vives, María Carmen; Martín, Susana; Ambrós, Silvia; Renovell, Agueda; Navarro, Luis; Pina, Jose Antonio; Moreno, Pedro; Guerri, José

    2008-11-01

    Citrus leaf blotch virus (CLBV), a member of the family Flexiviridae, has a ~9-kb single-stranded, positive-sense genomic RNA encapsidated by a 41-kDa coat protein. CLBV isolates are associated with symptom production in citrus including leaf blotching of Dweet tangor and stem pitting in Etrog citron (Dweet mottle disease), and some isolates are associated with bud union crease on trifoliate rootstocks, but Koch's postulates for this virus were not fulfilled. A full-genome cDNA of CLBV isolate SRA-153, which induces bud union crease, was placed under the T7 promoter (clone T7-CLBV), or between the 35S promoter and the Nos-t terminator, with or without a ribozyme sequence downstream of the CLBV sequence (clones 35SRbz-CLBV and 35S-CLBV). RNA transcripts from T7-CLBV failed to infect Etrog citron and Nicotiana occidentalis and N. benthamiana plants, whereas agro-inoculation with binary vectors carrying 35SRbz-CLBV or 35S-CLBV, and the p19 silencing suppressor, caused systemic infection and production of normal CLBV virions. Virus accumulation was similar in citron plants directly agro-infiltrated, or mechanically inoculated with wild-type or 35SRbz-CLBV-derived virions from Nicotiana, and the three sources incited the symptoms characteristic of Dweet mottle disease, but not bud union crease. Our results show that (1) virions derived from an infectious clone show the same replication, movement and pathogenicity characteristics as the wild-type CLBV; (2) CLBV is the causal agent of Dweet mottle disease but not of the bud union crease syndrome; and (3) for the first time an RNA virus could be successfully agro-inoculated on citrus plants. This infectious clone may become a useful viral vector for citrus genomic studies. PMID:19019007

  15. Resistance of poncirus and citrus x poncirus germplasm to the Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, has spread to citrus growing regions nearly worldwide and transmits phloem-limited bacteria (Candidatus Liberibacter spp.) that are putatively responsible for citrus greening disease. Host plant resistance may provide the most effective cont...

  16. Application of natural colorants on citrus fruit as alternatives to Citrus Red II

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Warm field temperatures can often result in poor peel color of some citrus varieties, especially early in the harvest season. Under these conditions, Florida oranges, temples, tangelos, and K-Early citrus fruit are allowed to be treated with Citrus Red No.2 (CR2) to help produce a more acceptable pe...

  17. Production of transgenic citrus resistant to citrus canker and Huanglongbing diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the U.S. citrus industry. There are no proven strategies to eliminate HLB disease and no cultivars identified with strong HLB resistance. Citrus canker is also an economically import...

  18. 78 FR 8435 - Importation of Fresh Citrus Fruit From Uruguay, Including Citrus Hybrids and Fortunella

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-06

    ...We are proposing to amend the fruits and vegetables regulations to allow the importation of several varieties of fresh citrus fruit, as well as Citrus hybrids and the Citrus-related genus Fortunella, from Uruguay into the continental United States. As a condition of entry, the fruit would have to be produced in accordance with a systems approach that would include requirements for importation......

  19. Alternaria toxins in wheat from the Autonomous Province of Vojvodina, Serbia: a preliminary survey.

    PubMed

    Janić Hajnal, Elizabet; Orčić, Dejan; Torbica, Aleksandra; Kos, Jovana; Mastilović, Jasna; Škrinjar, Marija

    2015-01-01

    Although Fusarium species remain a main source of mycotoxin contamination of wheat, in recent years, due to the evident climatic changes, other mycotoxigenic fungi have been recognised as important wheat contaminants. Alternaria species, especially A. alternata, have been found as contaminants of wheat as well as wheat-based products. Under favourable conditions A. alternata very often produce alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA) and others Alternaria toxins. The aim of the present study was to examine the presence of three Alternaria toxins (AOH, AME and TeA) in wheat samples harvested during three years (2011-13). To this end, 92 samples were collected during wheat harvesting from different growing regions of the Autonomous Province of Vojvodina, which represents the most important wheat-growing area in Serbia. The presence of Alternaria toxins was analysed by HPLC with electrospray ionisation triple quadrupole mass spectrometry (LC-ESI-MS/MS). Among all the analysed wheat samples, 63 (68.5%) were contaminated with TeA, 11 (12.0%) with AOH and 6 (6.5%) with AME. Furthermore, the maximum and mean toxin concentrations were 2676 and 92.4 µg kg(-1), 48.9 and 18.6 µg kg(-1), and 70.2 and 39.0 µg kg(-1) for TeA, AOH and AME, respectively. Co-occurrence of three Alternaria toxins in wheat samples was detected in six samples; a combination of two toxins was found in two samples; and 64 samples contained one toxin. The results showed that among 92 analysed wheat samples, only 20 (21.7%) samples were without Alternaria toxins. The presence of Alternaria toxins was also investigated in terms of weather conditions recorded during the period of investigation, as well as with the sampling region. This study represents the first preliminary report of the natural occurrence of Alternaria toxins in wheat (Triticum aestivum) from Serbia. PMID:25585540

  20. Primary subcutaneous Alternaria alternata infection of the hand in an immunocompromised host.

    PubMed

    Kpodzo, Dzifa S; Calderwood, Michael S; Ruchelsman, David E; Abramson, Jeremy S; Piris, Adriano; Winograd, Jonathan M; Kotton, Camille N

    2011-07-01

    We describe a case of a progressive subcutaneous Alternaria alternata infection in the hand of a patient with chronic lymphocytic leukemia (CLL). The diagnosis was based upon the examination of tissue biopsy and isolation of the etiologic agent in culture. The identity of the isolate was determined by phenotypic characteristics and by sequencing the ITS and D1/D2 regions of the rDNA. Despite combination therapy with voriconazole and micafungin, the lesion continued to progress. Posaconazole therapy, along with surgical excision of the infected tissue, resulted in the eradication of infection. The limitations of the clinical management of invasive Alternaria infections are discussed. PMID:21299373

  1. Photographic Remote Sensing of Sick Citrus Trees

    NASA Technical Reports Server (NTRS)

    Gausman, H. W.

    1971-01-01

    Remote sensing with infrared color aerial photography (Kodak Ektachrome Infrared Aero 8443 film) for detecting citrus tree anomalies is described. Illustrations and discussions are given for detecting nutrient toxicity symptoms, for detecting foot rot and sooty mold fungal diseases, and for distinguishing among citrus species. Also, the influence of internal leaf structure on light reflectance, transmittance, and absorptance are considered; and physiological and environmental factors that affect citrus leaf light reflectance are reviewed briefly and illustrated.

  2. Huanglongbing, a Systemic Disease, Restructures the Bacterial Community Associated with Citrus Roots▿

    PubMed Central

    Trivedi, Pankaj; Duan, Yongping; Wang, Nian

    2010-01-01

    To examine the effect of pathogens on the diversity and structure of plant-associated bacterial communities, we carried out a molecular analysis using citrus and huanglongbing as a host-disease model. 16S rRNA gene clone library analysis of citrus roots revealed shifts in microbial diversity in response to pathogen infection. The clone library of the uninfected root samples has a majority of phylotypes showing similarity to well-known plant growth-promoting bacteria, including Caulobacter, Burkholderia, Lysobacter, Pantoea, Pseudomonas, Stenotrophomonas, Bacillus, and Paenibacillus. Infection by “Candidatus Liberibacter asiaticus” restructured the native microbial community associated with citrus roots and led to the loss of detection of most phylotypes while promoting the growth of bacteria such as Methylobacterium and Sphingobacterium. In pairwise comparisons, the clone library from uninfected roots contained significantly higher 16S rRNA gene diversity, as reflected in the higher Chao 1 richness estimation (P ≤ 0.01) of 237.13 versus 42.14 for the uninfected and infected clone libraries, respectively. Similarly, the Shannon index of the uninfected clone library (4.46) was significantly higher than that of the infected clone library (2.61). Comparison of the uninfected clone library with the infected clone library using LIBSHUFF statistics showed a significant difference (P ≤ 0.05). Quantitative PCR analysis revealed that the bacterial community changes not only qualitatively but also quantitatively. The relative proportions of different groups of bacteria changed significantly after infection with the pathogen. These data indicate that infection of citrus by “Ca. Liberibacter asiaticus” has a profound effect on the structure and composition of the bacterial community associated with citrus roots. PMID:20382817

  3. Direct detection and quantification of Alternaria alternata lycopersici toxins using high-performance liquid chromatography-evaporative light-scattering detection.

    PubMed

    Xu, Li; Du, Liangcheng

    2006-03-01

    Alternaria alternata lycopersici toxins are produced by the tomato pathogenic fungus A. alternata f. sp. lycopersici. They are primary determinants for stem canker disease of tomato and induce apoptosis in animals and plants. Due to the lack of a UV chromophore, their detection has relied on derivatizations or immunoassays, which require tedious pre-assay processes. Here, we describe a method for direct and quantitative detection of the toxins. The method employs an evaporative light-scattering detector (ELSD) coupled to HPLC. It gives a linear response in the range of 400-4000 ng toxin, with a detection limit of about 6 ng/mul. The detection of all major toxin congeners by HPLC-ESLD was confirmed by liquid chromatography-mass spectrometry. Thus, the method provides a simple and sensitive tool for the studies of this group of host-specific mycotoxins. PMID:16014317

  4. Entomopathogenic fungus, Isaria fumosorosea, and aphid parasitoid, Lysiphlebus testaceipes, for managing infestations of Brown citrus aphid, Toxoptera citricida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An insect-infecting fungal pathogen, (Isaria fumosorosea [Ifr])sold as the product PFR 97™ was shown to be effective at killing aphid pests while not decreasing beneficial parasitoids. The brown citrus aphid, Toxoptera citricida (Kirkaldy)(Hemiptera: Aphididae) spreads the plant-infecting virus, Cit...

  5. Heat treatment of Huanglongbing–affected citrus trees in field for reduction of “Candidatus Liberibacter asiaticus”

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB, yellow shoot disease) is a devastating citrus disease worldwide. Research conducted by Lin Kung-Hisang et al. in 1960s China suggested that heat treatments were effective at eliminating the pathogen that causes HLB from scions. We tested the effects of high temperature on the red...

  6. Nonpathogenic Binucleate Rhizoctonia spp. and Benzothiadiazole Protect Cotton Seedlings Against Rhizoctonia Damping-Off and Alternaria Leaf Spot in Cotton.

    PubMed

    Jabaji-Hare, Suha; Neate, Stephen M

    2005-09-01

    ABSTRACT Recent reports have shown induction of resistance to Rhizoctonia root rot using nonpathogenic strains of binucleate Rhizoctonia spp. (np-BNR). This study evaluates the biocontrol ability of several np-BNR isolates against root and foliar diseases of cotton in greenhouse trials, provides evidence for induced systemic resistance (ISR) as a mechanism in this biocontrol, and compares the disease control provided by np-BNR with that provided by the chemical inducer benzothiadiazole (BTH). Pretreatment of cotton seedlings with np-BNR isolates provided good protection against pre- and post-emergence damping-off caused by a virulent strain of Rhizoctonia solani (AG-4). Seedling stand of protected cotton was significantly higher (P < 0.05) than that of nonprotected seedlings. Several np-BNR isolates significantly reduced disease severity. The combination of BTH and np-BNR provided significant protection against seedling rot and leaf spot in cotton; however, the degree of disease reduction was comparable to that obtained with np-BNR treatment alone. Significant reduction in leaf spot symptoms caused by Alternaria macrospora occurred on cotyledons pretreated with np-BNR or sprayed with BTH, and the np- BNR-treated seedlings had significantly less leaf spot than BTH-treated seedlings. The results demonstrate that np-BNR isolates can protect cotton from infections caused by both root and leaf pathogens and that disease control was superior to that observed with a chemical inducer. PMID:18943300

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Efficacy of a pyrimidine derivative to control spot disease on Solanum melongena caused by Alternaria alternata.

    PubMed

    Hassan, Nemat M; Abu-Doubara, Mohamed I; Waly, Mohamed A; Nemat Alla, Mamdouh M

    2013-07-01

    The pyrimidine derivative (4,6-dimethyl-N-phenyldiethyl pyrimidine, DPDP) was tested as a foliar spray fungicide at 50 mg l(-1) for protection of eggplant (Solanum melongena) from spot disease caused by Alternaria alternata. Varied concentrations of DPDP (10-50 mg l(-1)) differentially inhibited mycelial growth, conidial count and conidial germination of A. alternata growth in vitro; the magnitude of inhibition increased with increasing concentration. In vivo, an experiment was conducted in pots using a complete block randomized design and repeated twice with three replications and four treatments (control, A. alternata alone, DPDP alone and combination of DPDP and A. alternata) for 5 weeks (1 plant in pot × 3 pots per set (3 replications per treatment) × 4 sets (4 treatments) × 5 weeks × 2 experimental repetitions = 120 pots). In this experiment, 10-day-old eggplant seedlings were transplanted in pots and then inoculated with A. alternata, DPDP or their combination 1 week later. Leaves of the A. alternata-infected eggplant suffered from chlorosis, necrosis and brown spots during the subsequent 5 weeks. Disease intensity was obvious in infected leaves but withdrawn by DPDP. There were relationships between incidence and severity, greater in plant leaves infected A. alternata alone and diminished with the presence of DPDP. Moreover, the infection resulted in reductions in growth, decreases in contents of anthocyanins, chlorophylls, carotenoids and thiols as well as inhibitions in activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and glutathione-S-transferase (GST). Nonetheless, the application of DPDP at 50 mg led to a recovery of the infected eggplant; the infection-induced deleterious effects were mostly reversed by DPDP. However, treatment with DPDP alone seemed with no significant impacts. Due to its safe use to host and the inhibition for the pathogen, DPDP could be suggested as an efficient fungicide for protection

  9. Genome sequence of a novel mitovirus identified in the phytopathogenic fungus Alternaria arborescens.

    PubMed

    Komatsu, Ken; Katayama, Yukie; Omatsu, Tsutomu; Mizutani, Tetsuya; Fukuhara, Toshiyuki; Kodama, Motoichiro; Arie, Tsutomu; Teraoka, Tohru; Moriyama, Hiromitsu

    2016-09-01

    The phytopathogenic fungus Alternaria spp. contains a variety of double-stranded RNA (dsRNA) elements of different sizes. Detailed analysis of next-generation sequencing data obtained using dsRNA purified from Alternaria arborescens, from which we had previously found Alternaria arborescens victorivirus 1, revealed the presence of another mycoviral-like dsRNA of approximately 2.5 kbp in length. When using the fungal mitochondrial genetic code, this dsRNA has a single open reading frame that potentially encodes an RNA-dependent RNA polymerase (RdRp) with significant to sequence similarity to those of viruses of the genus Mitovirus. Moreover, both the 5'- and 3'-untranslated regions have the potential to fold into stable stem-loop structures, which is characteristic of mitoviruses. Pairwise comparisons and phylogenetic analysis of the deduced amino acid sequences of RdRp indicated that the virus we identified in A. arborescens is a distinct member of the genus Mitovirus in the family Narnaviridae, designated as "Alternaria arborescens mitovirus 1" (AaMV1). PMID:27368994

  10. Identification and functional analysis of brassicicene C biosynthetic gene cluster in Alternaria brassicicola.

    PubMed

    Minami, Atsushi; Tajima, Naoto; Higuchi, Yusuke; Toyomasu, Tomonobu; Sassa, Takeshi; Kato, Nobuo; Dairi, Tohru

    2009-02-01

    The biosynthetic gene cluster of brassicicene C was identified in Alternaria brassicicola strain ATCC 96836 from genome database search. In vivo and in vitro study clearly revealed the function of Orf8 and Orf6 as a fusicoccadiene synthase and methyltransferase, respectively. The understanding toward the biosynthetic pathway promises construction of this type of diterpene compounds with genetic engineering. PMID:19097780

  11. Antileukemic alpha-pyrone derivatives from the endophytic fungus Alternaria phragmospora

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four new (1–4) and two known (5 and 6)a-pyrone derivatives have been isolated from Alternaria phragmospora, an endophytic fungus from Vinca rosea, leaves. The isolated compounds were chemically identi'ed to be 5-butyl-4-methoxy-6-methyl-2H-pyran-2-one (2) 5-butyl-6-(hydroxymethyl)-4-methoxy-2H-py...

  12. Biochemical Evaluation of Resistance Responses of Potato to Different Isolates of Alternaria Solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The resistance phenotypes of nine potato cultivars to five isolates of Alternaria solani, causal agent of early blight, were studied after inoculation and growth under greenhouse conditions. We identified potato cultivars with both susceptible and resistant phenotypes as well as A. solani isolates ...

  13. Stability of Sweet Potato Cultivars to Alternaria Leaf and Stem Blight Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternaria leaf petiole and stem blight is an economically important disease of sweet potato (Ipomoea batatus L) in tropical and sub-tropical environments. Published research on cultivar resistance to the sweet potato disease is limited. To evaluate cultivar reaction and stability to the disease, mu...

  14. Refinement of the Citrus tristeza virus resistance gene (Ctv) positional map in Poncirus trifoliata and generation of transgenic grapefruit (Citrus paradisi) plant lines with candidate resistance genes in this region.

    PubMed

    Rai, Mamta

    2006-06-01

    Citrus tristeza virus (CTV) is a major pathogen of Citrus. A single dominant gene Ctv present in the trifoliate relative of Citrus, Poncirus trifoliata confers broad spectrum resistance against CTV. Refinement of genetic maps has delimited this gene to a 121 kb region, comprising of ten candidate Ctv resistance genes. The ten candidate genes were individually cloned in Agrobacterium based binary vector and transformed into three CTV susceptible grapefruit varieties. Two of the candidate R-genes, R-2 and R-3 are exclusively expressed in transgenic plants and in Poncirus trifoliata, while five other genes are also expressed in non-transformed Citrus controls. Northern blotting with a CTV derived probe for assessment of infection in virus inoculated plants over a span of three growth periods, each comprising of six to eight weeks, indicates either an absence of initiation of infection or it's slow spread in R-2 plant lines or an initial appearance of infection and it's subsequent obliteration in some R-1 and R-4 plant lines. Limited genome walk up- and downstream form R-1 gene, based on it's 100% sequence identity between Poncirus and Citrus, indicates promoter identity of 92% between the two varieties. Further upstream and downstream sequencing indicates the presence of an O-methyl transferase and a Copia like gene respectively in Citrus instead of the amino acid transporter like gene upstream and a sugar transporter like gene downstream in Poncirus. The possibility of recombinations in the resistance locus of Citrus and the need for consistent monitoring for virus infection and gene expression in the transgenic Citrus trees is discussed. PMID:16830176

  15. Amplification of DNA of Xanthomonas axonopodis pv. citri from historic citrus canker herbarium specimens.

    PubMed

    Li, Wenbin; Brlansky, Ronald H; Hartung, John S

    2006-05-01

    Herbaria are important resources for the study of the origins and dispersal of plant pathogens, particularly bacterial plant pathogens that incite local lesions in which large numbers of pathogen genomes are concentrated. Xanthomonas axonopodis pv. citri (Xac), the causal agent of citrus bacterial canker disease, is a notable example of such a pathogen. The appearance of novel strains of the pathogen in Florida and elsewhere make it increasingly important to understand the relationships among strains of this pathogen. USDA-ARS at Beltsville, Maryland maintains approximately 700 herbarium specimens with citrus canker disease lesions up to 90 years old, originally collected from all over the world, and so is an important resource for phytogeographic studies of this bacterium. Unfortunately, DNA in herbarium specimens is degraded and may contain high levels of inhibitors of PCR. In this study, we compared a total of 23 DNA isolation techniques in combination with 31 novel primer pairs in order to develop an efficient protocol for the analysis of Xac DNA in herbarium specimens. We identified the most reliable extraction method, identified in terms of successful amplification by our panel of 31 primer pairs. We also identified the most robust primer pairs, identified as successful in the largest number of extracts prepared by different methods. We amplified Xac genomic sequences up to 542 bp long from herbarium samples up to 89 years old. Primers varied in effectiveness, with some primer pairs amplifying Xac DNA from a 1/10,000 dilution of extract from a single lesion from a citrus canker herbarium specimen. Our methodology will be useful to identify pathogens and perform molecular analyses of bacterial and possibly fungal genomes from herbarium specimens. PMID:16099061

  16. Artificial neural network models of relationships between Alternaria spores and meteorological factors in Szczecin (Poland)

    NASA Astrophysics Data System (ADS)

    Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

    2008-11-01

    Alternaria is an airborne fungal spore type known to trigger respiratory allergy symptoms in sensitive patients. Aiming to reduce the risk for allergic individuals, we constructed predictive models for the fungal spore circulation in Szczecin, Poland. Monthly forecasting models were developed for the airborne spore concentrations of Alternaria, which is one of the most abundant fungal taxa in the area. Aerobiological sampling was conducted over 2004-2007, using a Lanzoni trap. Simultaneously, the following meteorological parameters were recorded: daily level of precipitation; maximum and average wind speed; relative humidity; and maximum, minimum, average, and dew point temperature. The original factors as well as with lags (up to 3 days) were used as the explaining variables. Due to non-linearity and non-normality of the data set, the modelling technique applied was the artificial neural network (ANN) method. The final model was a split model with classification (spore presence or absence) followed by regression for spore seasons and log(x+1) transformed Alternaria spore concentration. All variables except maximum wind speed and precipitation were important factors in the overall classification model. In the regression model for spore seasons, close relationships were noted between Alternaria spore concentration and average and maximum temperature (on the same day and 3 days previously), humidity (with lag 1) and maximum wind speed 2 days previously. The most important variable was humidity recorded on the same day. Our study illustrates a novel approach to modelling of time series with short spore seasons, and indicates that the ANN method provides the possibility of forecasting Alternaria spore concentration with high accuracy.

  17. Stubborn Disease of Citrus in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper is aimed at growers and nursery persons. It reviews the biology and phytopathology of citrus stubborn disease, and provides an update of our recent activities in this area. Stubborn disease of citrus was first reported in Redlands, California in 1918. However, the causal agent was not ide...

  18. Functional analysis of block deesterified citrus pectins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    After removal of soluble sugars and other compounds by washing, citrus peel is largely composed of pectin, cellulose and hemicellulose. In order to utilize the greatest amount of citrus peel product, it would appear reasonable that one or all three of these polysaccharides be converted to a useful ...

  19. HUANGLONGBING, CITRUS GREENING: PREPARING FOR THE FUTURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), more commonly known as citrus greening disease, was found in Florida in August 2005; Diaphorina citri Kuwayama, the Asian citrus psyllid and insect vector of HLB, was found in Florida in 1998. Since the initial discovery, the presence of HLB has been confirmed by polymerase cha...

  20. Conservation of citrus germplasm - an international survey

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus is an economically important tree fruit crop in many subtropical and tropical areas. Most cultivated species likely originated in Southern China, Northeast India and Southeast Asia. Many species are inter-fertile and some cultivated citrus types including sweet orange, lemon and grapefruit, ...

  1. Cryopreservation and Cryotherapy of Citrus Cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  2. Citrus Community College District Mentor Program.

    ERIC Educational Resources Information Center

    Hinds, Diane; Sprague, Caroline

    The Citrus College faculty and staff addressed the problem of lower career aspirations among women by establishing a support group, Citrus Women in Higher Education (CWHE). In addition to group meetings and special programs of interest, the CWHE has developed a mentor program to address the problem of blocked careers faced by women. The goals of…

  3. CURRENT EPIDEMIOLOGICAL UNDERSTANDING OF CITRUS HUANGLONGBING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is the most destructive citrus pathosystem worldwide. Previously known primarily from Asia and Africa it was introduced into the Western hemisphere in 2004. All infected commercial citrus industries continue to decline due to inadequate current control methods. HLB increase an...

  4. Rapid cyling plant breeding in citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  5. Asian citrus psyllid, genetic basis of immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We successfully used a genomics approach to determine some of the genes which function in immunity, stress, and insecticide resistance in the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae). These psyllids are vectors of the devastating disease, Huanglongbing, now affecting citrus in F...

  6. RNA-Seq derived identification of differential transcription in the chrysanthemum leaf following inoculation with Alternaria tenuissima

    PubMed Central

    2014-01-01

    Background A major production constraint on the important ornamental species chrysanthemum is black spot which is caused by the necrotrophic fungus Alternaria tenuissima. The molecular basis of host resistance to A. tenuissima has not been studied as yet in any detail. Here, high throughput sequencing was taken to characterize the transcriptomic response of the chrysanthemum leaf to A. tenuissima inoculation. Results The transcriptomic data was acquired using RNA-Seq technology, based on the Illumina HiSeq™ 2000 platform. Four different libraries derived from two sets of leaves harvested from either inoculated or mock-inoculated plants were characterized. Over seven million clean reads were generated from each library, each corresponding to a coverage of >350,000 nt. About 70% of the reads could be mapped to a set of chrysanthemum unigenes. Read frequency was used as a measure of transcript abundance and therefore as an identifier of differential transcription in the four libraries. The differentially transcribed genes identified were involved in photosynthesis, pathogen recognition, reactive oxygen species generation, cell wall modification and phytohormone signalling; in addition, a number of varied transcription factors were identified. A selection of 23 of the genes was transcription-profiled using quantitative RT-PCR to validate the RNA-Seq output. Conclusions A substantial body of chrysanthemum transcriptomic sequence was generated, which led to a number of insights into the molecular basis of the host response to A. tenuissima infection. Although most of the differentially transcribed genes were up-regulated by the presence of the pathogen, those involved in photosynthesis were down-regulated. PMID:24387266

  7. Extracellular matrix-associated proteome changes during non-host resistance in citrus-Xanthomonas interactions.

    PubMed

    Swaroopa Rani, Tirupaati; Podile, Appa Rao

    2014-04-01

    Non-host resistance (NHR) is a most durable broad-spectrum resistance employed by the plants to restrict majority of pathogens. Plant extracellular matrix (ECM) is a critical defense barrier. Understanding ECM responses during interaction with non-host pathogen will provide insights into molecular events of NHR. In this study, the ECM-associated proteome was compared during interaction of citrus with pathogen Xanthomonas axonopodis pv. citri (Xac) and non-host pathogen Xanthomonas oryzae pv. oryzae (Xoo) at 8, 16, 24 and 48 h post inoculation. Comprehensive analysis of ECM-associated proteins was performed by extracting wall-bound and soluble ECM components using both destructive and non-destructive procedures. A total of 53 proteins was differentially expressed in citrus-Xanthomonas host and non-host interaction, out of which 44 were identified by mass spectrometry. The differentially expressed proteins were related to (1) defense-response (5 pathogenesis-related proteins, 3 miraculin-like proteins (MIR, MIR1 and MIR2) and 2 proteases); (2) enzymes of reactive oxygen species (ROS) metabolism [Cu/Zn superoxide dismutase (SOD), Fe-SOD, ascorbate peroxidase and 2-cysteine-peroxiredoxin]; (3) signaling (lectin, curculin-like lectin and concanavalin A-like lectin kinase); and (4) cell-wall modification (α-xylosidase, glucan 1, 3 β-glucosidase, xyloglucan endotransglucosylase/hydrolase). The decrease in ascorbate peroxidase and cysteine-peroxiredoxin could be involved in maintenance of ROS levels. Increase in defense, cell-wall remodeling and signaling proteins in citrus-Xoo interaction suggests an active involvement of ECM in execution of NHR. Partially compromised NHR in citrus against Xoo, upon Brefeldin A pre-treatment supported the role of non-classical secretory proteins in this phenomenon. PMID:24117905

  8. Tolerance of the trifoliate citrus hybrid US-897 (Citrus reticulata Blanco x Poncirus trifoliata L. Raf.) to Huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a destructive disease of citrus in most citrus-producing countries worldwide. The disease, presumably caused by phloem-limited bacteria of the genus Candidatus Liberibacter, affects all known citrus species and citrus relatives with little known resistance. Typical disease s...

  9. A COMPARISON OF TRAPS AND TAP SAMPLING FOR MONITORING ADULT ASIAN CITRUS PSYLLID, DIAPHORINA CITRI KUWAYMA (HOMOPTERA: PSYLLIDAE), IN CITRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama, was first found in Florida during June 1998 and subsequently spread throughout the state's citrus-growing regions. D. citri vectors the bacterium, Candidatus Liberibacter asiaticus, responsible for citrus greening disease (huanglongbing). Citrus g...

  10. Deciphering the Bacterial Microbiome in Huanglongbing-Affected Citrus Treated with Thermotherapy and Sulfonamide Antibiotics.

    PubMed

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

    2016-01-01

    Huanglongbing (HLB) is a serious citrus disease that threatens the citrus industry. In previous studies, sulfonamide antibiotics and heat treatment suppressed 'Candidatus Liberibacter asiaticus' (Las), but did not completely eliminate the Las. Furthermore, there are few reports studying the bacterial microbiome of HLB-affected citrus treated by heat and sulfonamide antibiotics. In this study, combinations of heat (45°C or 40°C) and sulfonamide treatment (sulfathiazole sodium-STZ, or sulfadimethoxine sodium-SDX) were applied to HLB-affected citrus. The bacterial microbiome of HLB-affected citrus following thermotherapy and/or chemotherapy was characterized by PhyloChipTMG3-based metagenomics. Our results showed that the combination of thermotherapy at 45°C and chemotherapy with STZ and SDX was more effective against HLB than thermotherapy alone, chemotherapy alone, or a combination of thermotherapy at 40°C and chemotherapy. The PhyloChipTMG3-based results indicated that 311 empirical Operational Taxonomic Units (eOTUs) were detected in 26 phyla. Cyanobacteria (18.01%) were dominant after thermo-chemotherapy. Thermotherapy at 45°C decreased eOTUs (64.43%) in leaf samples, compared with thermotherapy at 40°C (73.96%) or without thermotherapy (90.68%) and it also reduced bacterial family biodiversity. The eOTU in phylum Proteobacteria was reduced significantly and eOTU_28, representing "Candidatus Liberibacter," was not detected following thermotherapy at 45°C. Following antibiotic treatment with SDX and STZ, there was enhanced abundance of specific eOTUs belonging to the families Streptomycetaceae, Desulfobacteraceae, Chitinophagaceae, and Xanthomonadaceae, which may be implicated in increased resistance to plant pathogens. Our study further develops an integrated strategy for combating HLB, and also provides new insight into the bacterial microbiome of HLB-affected citrus treated by heat and sulfonamide antibiotics. PMID:27171468

  11. Deciphering the Bacterial Microbiome in Huanglongbing-Affected Citrus Treated with Thermotherapy and Sulfonamide Antibiotics

    PubMed Central

    Powell, Charles A.; Duan, Yongping; Shatters, Robert; Fang, Jingping; Zhang, Muqing

    2016-01-01

    Huanglongbing (HLB) is a serious citrus disease that threatens the citrus industry. In previous studies, sulfonamide antibiotics and heat treatment suppressed ‘Candidatus Liberibacter asiaticus’ (Las), but did not completely eliminate the Las. Furthermore, there are few reports studying the bacterial microbiome of HLB-affected citrus treated by heat and sulfonamide antibiotics. In this study, combinations of heat (45°C or 40°C) and sulfonamide treatment (sulfathiazole sodium–STZ, or sulfadimethoxine sodium—SDX) were applied to HLB-affected citrus. The bacterial microbiome of HLB-affected citrus following thermotherapy and/or chemotherapy was characterized by PhyloChipTMG3-based metagenomics. Our results showed that the combination of thermotherapy at 45°C and chemotherapy with STZ and SDX was more effective against HLB than thermotherapy alone, chemotherapy alone, or a combination of thermotherapy at 40°C and chemotherapy. The PhyloChipTMG3-based results indicated that 311 empirical Operational Taxonomic Units (eOTUs) were detected in 26 phyla. Cyanobacteria (18.01%) were dominant after thermo-chemotherapy. Thermotherapy at 45°C decreased eOTUs (64.43%) in leaf samples, compared with thermotherapy at 40°C (73.96%) or without thermotherapy (90.68%) and it also reduced bacterial family biodiversity. The eOTU in phylum Proteobacteria was reduced significantly and eOTU_28, representing “Candidatus Liberibacter,” was not detected following thermotherapy at 45°C. Following antibiotic treatment with SDX and STZ, there was enhanced abundance of specific eOTUs belonging to the families Streptomycetaceae, Desulfobacteraceae, Chitinophagaceae, and Xanthomonadaceae, which may be implicated in increased resistance to plant pathogens. Our study further develops an integrated strategy for combating HLB, and also provides new insight into the bacterial microbiome of HLB-affected citrus treated by heat and sulfonamide antibiotics. PMID:27171468

  12. Effect of neem (Azardirachta indica A. Juss) seeds and leaves extract on some plant pathogenic fungi.

    PubMed

    Moslem, M A; El-Kholie, E M

    2009-07-15

    In this study plant pathogenic fungi Alternaria solani, Fusarium oxysporum, Rhizoctonia solani and Sclerotinia sclerotiorum were chosen to study the effect of ethanolic, hexane and methanolic extracts of neem seeds and leaves. Antifungal effects of neem leave and seed extracts obtained by ethanol, hexane and ptrolium ether were examined separately in vitro against Fusarium oxysporum, Rhizoctonia solani, Alternaria solani and Sclerotinia sclerotiorum. Results indicated that seeds and leaves extracts could cause growth inhibition of tested fungi, although the rate of inhibition of tested fungi varied with different extracts and concentrations. But all these extracts and concentrations of extract inhibited the growth of pathogenic fungi at a significant level. Azadirachtin, nimonol and expoxyazdirodione were detected from neem extract by using High Performance Liquid Chromatography (HPLC). We can conclude that neem leave and seed extracts were effective as antifungal against all tested fungi but F. oxysporum and R. solani were the most sensitive fungi. PMID:19947185

  13. Accumulation of the sesquiterpenes nootkatone and valencene by callus cultures of Citrus paradisi, Citrus limonia and Citrus aurantium.

    PubMed

    Del Río, J A; Ortuño, A; Puig, D G; Iborra, J L; Sabater, F

    1991-10-01

    The production of the sesquiterpenes nootkatone and valencene by callus cultures of Citrus species is described. The levels of these compounds were examined by gas chromatography-mass spectrometry and their yields were compared with the amounts found in mature fruits. A simultaneous increase and decrease in the levels of nootkatone and valencene, respectively, were observed with the aging of callus cultures of Citrus paradisi. These results suggest that valencene might be a possible precursor of nootkatone in this species. The high level of nootkatone detected in 9-month-old callus cultures of Citrus paradisi might be associated with the corresponding cell morphological changes observed. PMID:24221735

  14. Citrus leprosis virus vectored by Brevipalpus phoenicis (Acari: Tenuipalpidae) on citrus in Brazil.

    PubMed

    Rodrigues, J C V; Kitajima, E W; Childers, C C; Chagas, C M

    2003-01-01

    Citrus leprosis is caused by Citrus leprosis virus (CiLV) that is transmitted by mites in the genus Brevipalpus (Acari: Tenuipalpidae). This disease directly reduces production and the life span of the citrus plant. The main symptoms of the disease include lesions on fruits, leaves, and twigs or small branches, causing premature fruit drop, defoliation, and death of the twigs or branches leading to serious tree decline. Leprosis is a highly destructive disease of citrus, wherever it occurs. The Brazilian citrus industry spends over 100 million US dollars annually on acaricides to control the vector, Brevipalpus phoenicis (Geijskes). This review contains information about the history of the etiology of citrus leprosis, its geographical distribution, host range, the role of the mite vectors, viral morphology and relationships with the infected cell, and transmissibility of the virus by the mite. In addition, data on the mite-virus-plant relationship, disease damage, and strategies for controlling disease spread are presented. PMID:14756415

  15. Chipping citrus wood for gasifiction

    SciTech Connect

    Churchill, D.B.; Hedden, S.L.; Whitney, J.D.; Shaw, L.N.

    1984-01-01

    Both green and dead citrus trees were used for chipping. Chip moisture content, fuel analysis, drying time, and data on fuel/tonne of chips were obtained. The average moisture contents of green and dead trees when chipped were 25% and 16% (wet basis) respectively. Chips were sized to a minimum of 0.32 squared cm x 0.32 cm thick to a maximum of 5.0 cm squared x 0.32 cm thick and normally required 4 weeks to air dry to 14% (wet basis) moisture content before use. Approximately 50% of the total tree by weight could be made into usable chips. 9 references.

  16. Bloodborne pathogens

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000453.htm Bloodborne pathogens To use the sharing features on this page, please enable JavaScript. A pathogen is something that causes disease. Germs that can ...

  17. Citrus breeding, genetics and genomics in Japan.

    PubMed

    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

  18. Citrus breeding, genetics and genomics in Japan

    PubMed Central

    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

  19. Antimicrobial activity of wax and hexane extracts from Citrus spp. peels.

    PubMed

    Johann, Susana; Oliveira, Vetúria Lopes de; Pizzolatti, Moacir G; Schripsema, Jan; Braz-Filho, Raimundo; Branco, Alexsandro; Smânia Jr, Artur

    2007-09-01

    Antibacterial and antifungal properties of wax and hexane extracts of Citrus spp. peels were tested using bioautographic and microdilution techniques against three plant pathogenic fungi (Penicillium digitatum, Curvularia sp., and Colletotrichum sp.), two human pathogens (Trichophyton mentagrophytes and Microsporum canis), and two opportunistic bacteria (Escherichia coli and Staphylococcus aureus). Two polymethoxylated flavonoids and a coumarin derivative, were isolated and identified from peel extracts, which presented antimicrobial activity especially against M. canis and T. mentagrophytes: 4',5,6,7,8-pentamethoxyflavone (tangeritin) and 3',4',5,6,7,8-hexamethoxyflavone (nobiletin) from C. reticulata; and 6,7-dimethoxycoumarin (also known as escoparone, scoparone or scoparin) from C. limon. PMID:17923995

  20. Development of a polymerase chain reaction-based assay for the detection of Alternaria fungal contamination in food products.

    PubMed

    Zur, G; Hallerman, E M; Sharf, R; Kashi, Y

    1999-10-01

    Alternaria sp. are important fungal contaminants of vegetable, fruit, and grain products, including Alternaria alternata, a contaminant of tomato products. To date, the Howard method, based on microscopic observation of fungal filaments, has been the standard examination for inspection of tomato products. We report development of a polymerase chain reaction (PCR)-based method for detection of Alternaria DNA. PCR primers were designed to anneal to the internal transcribed regions ITS1 and ITS2 of the 5.8S rRNA gene of Alternaria but not to other microbial or tomato DNA. We demonstrate use of the PCR assay to detect Alternaria DNA in experimentally infested and commercially obtained tomato sauce and tomato powder. Use of the PCR method offers a rapid and sensitive assay for the presence of Alternaria DNA in tomato products. The apparent breakdown of DNA in tomato sauce may limit the utility of the assay to freshly prepared products. The assay for tomato powder is not affected by storage time. PMID:10528725

  1. Characterization of the Asian Citrus Psyllid Transcriptome

    PubMed Central

    Reese, Justin; Christenson, Matthew K.; Leng, Nan; Saha, Surya; Cantarel, Brandi; Lindeberg, Magdalen; Tamborindeguy, Cecilia; MacCarthy, Justin; Weaver, Daniel; Trease, Andrew J.; Ready, Steven V.; Davis, Vincent M.; McCormick, Courtney; Haudenschild, Christian; Han, Shunsheng; Johnson, Shannon L.; Shelby, Kent S.; Huang, Hong; Bextine, Blake R.; Shatters, Robert G.; Hall, David G.; Davis, Paul H.; Hunter, Wayne B.

    2014-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a vector for the causative agents of Huanglongbing, which threatens citrus production worldwide. This study reports and discusses the first D. citri transcriptomes, encompassing the three main life stages of D. citri, egg, nymph and adult. The transcriptomes were annotated using Gene Ontology (GO) and insecticide-related genes within each life stage were identified to aid the development of future D. citri insecticides. Transcriptome assemblies and other sequence data are available for download at the International Asian Citrus Psyllid Genome Consortium website [http://psyllid.org/download] and at NCBI [http://www.ncbi.nlm.nih.gov/bioproject/29447]. PMID:24511328

  2. Characterization of Basidiomycetes associated with wood rot of citrus in southern Italy.

    PubMed

    Roccotelli, Angela; Schena, Leonardo; Sanzani, Simona M; Cacciola, Santa O; Mosca, Saveria; Faedda, Roberto; Ippolito, Antonio; di San Lio, Gaetano Magnano

    2014-08-01

    The characterization of Basidiomycetes associated with wood rots in commercial citrus orchards in southern Italy revealed that both white and brown rot fungi are implicated in this disease. Fomitiporia mediterranea was the most prevalent species causing a white rot, followed by Fomitopsis sp. which, by contrast, was associated with brown rot wood decay. Furthermore, Phellinus spp. and other nonidentified basidiomycetous fungi showing genetic affinity with the genera Phellinus and Coniophora were occasionally isolated. Artificial inoculations on lemon (Citrus limon) branches showed a faster wood colonization by Fomitopsis sp. compared with F. mediterranea, indicating that the former species as a potentially serious pathogen of citrus trees. The analysis of F. mediterranea internal transcribed spacer (ITS) sequences revealed a high level of genetic variability, with 13 genotypes which were both homozygous (6 genotypes) and heterozygous (7 genotypes). The presence of heterozygous genomes based on ITS sequences has never been reported before for F. mediterranea. This, together with the high frequency of basidiomata on infected wood, unambiguously confirms the outcrossing nature of reproduction in F. mediterranea and the primary role of basidiospores in the dissemination of inoculum. Similarly, high genetic variability was observed analyzing Fomitopsis sp. Because basidiomata of this fungus have not been observed on citrus trees, it can be hypothesized that basidiospores are produced on alternative host plants. PMID:24502208

  3. Chitinase-mediated inhibitory activity of Brassica transgenic on growth of Alternaria brassicae.

    PubMed

    Mondal, Kalyan K; Chatterjee, Subhas Chandra; Viswakarma, Navin; Bhattacharya, Ram Charan; Grover, Anita

    2003-09-01

    Chitinase, capable of degrading the cell walls of invading phytopathogenic fungi, plays an important role in plant defense response, particularly when this enzyme is overexpressed through genetic engineering. In the present study, Brassica plant (Brassica juncea L.) was transformed with chitinase gene tagged with an overexpressing promoter 35 S CaMV. The putative transgenics were assayed for their inhibitory activity against Alternaria brassicae, the inducer of Alternaria leaf spot of Brassica both in vitro and under polyhouse conditions. In in vitro fungal growth inhibition assays, chitinase inhibited the fungal colony size by 12-56% over the non-trangenic control. The bioassay under artificial epiphytotic conditions revealed the delay in the onset of disease as well as reduced lesion number and size in 35S-chitinase Brassica as compared to the untransformed control plants. PMID:14570264

  4. Four cases of dermatomycosis: superficial cutaneous infection by Alternaria or Bipolaris.

    PubMed

    Robb, Christopher W; Malouf, Peter J; Rapini, Ronald P

    2003-10-01

    Invasive dermal infections in immunosuppressed patients by a wide variety of opportunistic fungi are well described in the literature; however, superficial infections (dermatomycosis) are more rarely described. We report 4 cases of dermatomycosis by Alternaria or Bipolaris species. All but one of the patients had predisposing conditions including topical corticosteroid use, atopic or seborrheic dermatitis, and nail dystrophy. All 4 patients were otherwise immunocompetent. These cases represent some of the very few reports of Bipolaris in a primary stratum corneum infection and the first report of Bipolaris in an otherwise healthy person. We also describe what may be the first report of Bipolaris onychomycosis. All of our patients responded to topical or oral imidazole antifungal therapy. We discuss the significance of Alternaria and Bipolaris as contaminants or irrelevant organisms grown in some cultures of skin scrapings. PMID:14604084

  5. Degradation of the Alternaria mycotoxins alternariol, alternariol monomethyl ether, and altenuene upon bread baking.

    PubMed

    Siegel, David; Feist, Michael; Proske, Matthias; Koch, Matthias; Nehls, Irene

    2010-09-01

    The stability of the Alternaria mycotoxins alternariol, alternariol monomethyl ether, and altenuene upon bread baking was investigated by model experiments using a spiked wholemeal wheat flour matrix. For alternariol and alternariol monomethyl ether, but not for altenuene, degradation products, formed through a sequence of hydrolysis and decarboxylation, could be identified in pilot studies. The simultaneous quantification of alternariol, alternariol monomethyl ether, altenuene, and the degradation products was achieved by a newly developed high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) multimethod. The obtained quantitative data indicate that the Alternaria mycotoxins are barely degraded during wet baking, while significant degradation occurs upon dry baking, with the stability decreasing in the order alternariol monomethyl ether>alternariol>altenuene. The novel degradation products could be detected after the wet baking of flour spiked with alternariol and in a sample survey of 24 commercial cereal based baking products. PMID:20687560

  6. Genome sequence of a novel endornavirus from the phytopathogenic fungus Alternaria brassicicola.

    PubMed

    Shang, Hong-Hong; Zhong, Jie; Zhang, Ru-Jia; Chen, Chuan-Yuan; Gao, Bi-Da; Zhu, Hong-Jian

    2015-07-01

    In an effort to discover new mycoviruses from phytopathogenic fungi, a dsRNA molecule of 10,290 nt, resembling those associated with the viruses belonging to the family Endornaviridae, was isolated from Alternaria brassicicola, one of the causal agents of rapeseed black spot disease. Genome analysis revealed the presence of a single open reading frame coding for a polyprotein of 3400 aa containing conserved viral methyltransferase (MTR), viral RNA helicase 1 (Hel-1), and RNA-dependent RNA polymerase (RdRp) domains. In addition, a cysteine-rich region (CRR) with conserved CXCC motifs, shared among several endornaviruses, was also identified between the MTR and Hel-1 domains. Phylogenetic analysis based on the RdRp sequence strongly suggested that the virus infecting A. brassicicola should be considered a representative of a novel endornavirus species, and this virus was designated as Alternaria brassicicola endornavirus 1 (AbEV1). PMID:25951967

  7. Role of micronutrients in defense to white rust and Alternaria blight infecting Indian mustard.

    PubMed

    Rathi, A S; Singh, Dhiraj; Avtar, Ram; Kumar, Pawan

    2015-03-01

    Field experiments were carried out at Oilseeds Research Area of CCS Haryana Agricultural University, Hisar during rabi, 2008-09 to 2011-12 to find out the possible role of soil application of different micronutrients alone and in combinations in defense to white rust and Alternaria blight diseases in Indian mustard [Brassica juncea (L.) Czern & Coss.]. Among the sole application of micronutrients, minimum disease severity of both white rust (35.0%) and Alternaria blight (31.8%) was observed when S @ 40 kg ha in the form of Gypsum was applied as basal dose in the soil. When Gypsum was supplemented with Borax @10 kg ha(-1) or with ZnSO4 @15 kg ha(-1) the level of tolerance seems to be improved for both the diseases as compared to the sole treatment of each nutrient, i.e., ZnSO4 @ 15 kg/ha, Borax @ 10 kg ha' and Gypsum @ 250 kg ha(-1). Furthermore, minimum disease severity of both white rust (31.3 %) and Alternaria blight (26.3 %) was observed with soil application of ZnSO4 @ 15 kg ha(-1) + Borax @ 10 kg ha(-1) + Gypsum @250 kg ha(-1) as basal dose as compared to the severity of white rust (43.6%) and Alternaria blight (38.6%) in untreated check. Significant increase in seed yield (1612 kg ha(-1)) was also recorded in above mentioned treatment as compared to the yield (1337 kg ha(-1)) in untreated check. These findings will also be helpful in maintaining soil health and minimizing the losses due to both the fungal diseases for eco-friendly sustainability of Indian mustard. PMID:25895272

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

    PubMed

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

    2014-12-01

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

  9. Alternariol 9-methyl ether from the endophytic fungus Alternaria sp. Samif01 and its bioactivities.

    PubMed

    Lou, Jingfeng; Yu, Ruiting; Wang, Xiaohan; Mao, Ziling; Fu, Linyun; Liu, Yang; Zhou, Ligang

    2016-01-01

    One bioactive compound, identified as alternariol 9-methyl ether, was isolated from the crude extract of the endophytic fungus Alternaria sp. Samif01 residing in the roots of Salvia miltiorrhiza Bunge. Alternariol 9-methyl ether was active against bacteria with minimum inhibitory concentration values ranging from 25 to 75μg/mL and median inhibitory concentration (IC50) values ranging from 16.00 to 38.27μg/mL. The IC50 value of alternariol 9-methyl ether against spore germination of Magnaporthe oryzae was 87.18μg/mL. Alternariol 9-methyl ether also showed antinematodal activity against Bursaphelenchus xylophilus and Caenorhabditis elegans with IC50 values of 98.17μg/mL and 74.62μg/mL, respectively. This work is the first report on alternariol 9-methyl ether and its biological activities from the endophytic fungus Alternaria sp. Samif01 derived from S. miltiorrhiza Bunge. The results indicate the potential of Alternaria sp. Samif01 as a source of alternariol 9-methyl ether and also support that alternariol 9-methyl ether is a natural compound with high potential bioactivity against microorganisms. PMID:26887231

  10. Alternariol 9-methyl ether from the endophytic fungus Alternaria sp. Samif01 and its bioactivities

    PubMed Central

    Lou, Jingfeng; Yu, Ruiting; Wang, Xiaohan; Mao, Ziling; Fu, Linyun; Liu, Yang; Zhou, Ligang

    2016-01-01

    One bioactive compound, identified as alternariol 9-methyl ether, was isolated from the crude extract of the endophytic fungus Alternaria sp. Samif01 residing in the roots of Salvia miltiorrhiza Bunge. Alternariol 9-methyl ether was active against bacteria with minimum inhibitory concentration values ranging from 25 to 75 μg/mL and median inhibitory concentration (IC50) values ranging from 16.00 to 38.27 μg/mL. The IC50 value of alternariol 9-methyl ether against spore germination of Magnaporthe oryzae was 87.18 μg/mL. Alternariol 9-methyl ether also showed antinematodal activity against Bursaphelenchus xylophilus and Caenorhabditis elegans with IC50 values of 98.17 μg/mL and 74.62 μg/mL, respectively. This work is the first report on alternariol 9-methyl ether and its biological activities from the endophytic fungus Alternaria sp. Samif01 derived from S. miltiorrhiza Bunge. The results indicate the potential of Alternaria sp. Samif01 as a source of alternariol 9-methyl ether and also support that alternariol 9-methyl ether is a natural compound with high potential bioactivity against microorganisms. PMID:26887231

  11. Crop harvest in Central Europe causes episodes of high airborne Alternaria spore concentrations in Copenhagen

    NASA Astrophysics Data System (ADS)

    Skjøth, C. A.; Sommer, J.; Frederiksen, L.; Gosewinkel Karlson, U.

    2012-06-01

    This study tests the hypothesis that Danish agricultural areas are the main source to airborne Alternaria spores in Copenhagen, Denmark. We suggest that the source to the overall load is mainly local, but with intermittent Long Distance Transport (LDT) from more remote agricultural areas. This hypothesis is supported by investigating a 10 yr bi-hourly record of Alternaria spores in the air from Copenhagen. This record shows 232 clinically relevant episodes with a distinct daily profile. The data analysis also revealed potential LDT episodes almost every year. A source map and analysis of atmospheric transport suggest that LDT always originates from the main agricultural areas in Central Europe. A dedicated emission study in cereal crops under harvest during 2010 also supports our hypothesis. The emission study showed that although the fields had been treated against fungal infections, harvesting still produced large amounts of airborne fungal spores. It is likely that such harvesting periods can cause clinically relevant levels of fungal spores in the atmosphere. Our findings suggest that crop harvest in Central Europe causes episodes of high airborne Alternaria spore concentrations in Copenhagen as well as other urban areas in this region. It is likely that such episodes could be simulated using atmospheric transport models.

  12. Human eosinophil innate response to Alternaria fungus through protease-activated receptor-2.

    PubMed

    Matsuwaki, Yoshinori; Wada, Kota; Moriyama, Hiroshi; Kita, Hirohito

    2011-01-01

    Eosinophils are multifunctional leukocytes implicated in the pathogenesis of allergic diseases. An association between eosinophilic inflammation and infection or colonization by fungi has also been long recognized. However, the mechanisms underlying how eosinophils are activated and how they release proinflammatory and immunomodulatory mediators such as major basic protein (MBP) and eosinophil-derived neurotoxin remain largely unknown. We used a fungus, i.e. Alternaria, as a model microbe relevant to human asthma and chronic rhinosinusitis (CRS) to investigate the molecular mechanisms involved in the immune recognition of ubiquitous environmental allergens. Human eosinophils are activated by live Alternaria alternata organisms, release their granule proteins, and kill the fungi. Eosinophils, but not neutrophils, respond to secreted products from A. alternata. We found that eosinophils are equipped with innate cellular activation machinery that responds to an extracellular aspartate protease secreted by Alternaria. Aspartate protease activation of protease-activated receptor (PAR)-2 probably involves a novel mechanism different from that for serine protease activation of PAR-2. Thus, human eosinophils may recognize certain danger signals or virulence factors produced by fungi and provoke inflammatory responses against these organisms. Dysregulation of such an innate immune mechanism may be involved in the pathophysiology of certain human inflammatory diseases, including asthma and CRS. PMID:21646807

  13. Effects of meteorological factors on the levels of Alternaria spores on a potato crop

    NASA Astrophysics Data System (ADS)

    Escuredo, Olga; Seijo, Maria Carmen; Fernández-González, Maria; Iglesias, Isabel

    2011-03-01

    Alternaria solani Soraeur produces early blight in Solanum tuberosum L., leading to significant agricultural losses. The current study was carried out on the extensive potato crop situated in north-western of Spain during 2007, 2008 and 2009. In this area potato crops are the most important source of income. In this work we used a Hirst-type volumetric spore-trap for the aerobiological monitoring of Alternaria spores. The highest spore concentrations were recorded during the 2009 cycle (10,555 spores), and the lowest concentrations were recorded during the 2008 cycle (5,471 spores). Over the 3 years of study, the highest concentrations were registered during the last stage of the crop. The aim of the study was to observe the influence of meteorological factors on the concentration of Alternaria spores, which can lead to serious infection and early blight. Prediction of the stages during which a crop is particularly vulnerable to infection allows for adjustment of the application of fungicide and is of environmental and agricultural importance. For this reason, we tested three models (P-Days, DD and IWP) to predict the first treatment and decrease the negative effect that these spores have on potato crops. The parameter that showed the most significant correlation with spore concentrations was minimum temperature. We used ARIMA (autoregressive integrated model of running mean) time-series models to determine the forecast. We considered weather data as predictor variables and the concentration of spores on the previous day as the fixed variable.

  14. Production of the Allergenic Protein Alt a 1 by Alternaria Isolates from Working Environments

    PubMed Central

    Skóra, Justyna; Otlewska, Anna; Gutarowska, Beata; Leszczyńska, Joanna; Majak, Iwona; Stępień, Łukasz

    2015-01-01

    The aim of the study was to evaluate the ability of Alternaria isolates from workplaces to produce Alt a 1 allergenic protein, and to analyze whether technical materials (cellulose, compost, leather) present within the working environment stimulate or inhibit Alt a 1 production (ELISA test). Studies included identification of the isolated molds by nucleotide sequences analyzing of the ITS1/ITS2 regions, actin, calmodulin and Alt a 1 genes. It has been shown that Alternaria molds are significant part of microbiocenosis in the archive, museum, library, composting plant and tannery (14%–16% frequency in the air). The presence of the gene encoding the Alt a 1 protein has been detected for the strains: Alternaria alternata, A. lini, A. limoniasperae A. nobilis and A. tenuissima. Environmental strains produced Alt a 1 at higher concentrations (1.103–6.528 ng/mL) than a ATCC strain (0.551–0.975 ng/mL). It has been shown that the homogenization of the mycelium and the use of ultrafiltration allow a considerable increase of Alt a 1 concentration. Variations in the production of Alt a 1 protein, depend on the strain and extraction methods. These studies revealed no impact of the technical material from the workplaces on the production of Alt a 1 protein. PMID:25689994

  15. Production of the allergenic protein Alt a 1 by Alternaria isolates from working environments.

    PubMed

    Skóra, Justyna; Otlewska, Anna; Gutarowska, Beata; Leszczyńska, Joanna; Majak, Iwona; Stępień, Łukasz

    2015-02-01

    The aim of the study was to evaluate the ability of Alternaria isolates from workplaces to produce Alt a 1 allergenic protein, and to analyze whether technical materials (cellulose, compost, leather) present within the working environment stimulate or inhibit Alt a 1 production (ELISA test). Studies included identification of the isolated molds by nucleotide sequences analyzing of the ITS1/ITS2 regions, actin, calmodulin and Alt a 1 genes. It has been shown that Alternaria molds are significant part of microbiocenosis in the archive, museum, library, composting plant and tannery (14%-16% frequency in the air). The presence of the gene encoding the Alt a 1 protein has been detected for the strains: Alternaria alternata, A. lini, A. limoniasperae A. nobilis and A. tenuissima. Environmental strains produced Alt a 1 at higher concentrations (1.103-6.528 ng/mL) than a ATCC strain (0.551-0.975 ng/mL). It has been shown that the homogenization of the mycelium and the use of ultrafiltration allow a considerable increase of Alt a 1 concentration. Variations in the production of Alt a 1 protein, depend on the strain and extraction methods. These studies revealed no impact of the technical material from the workplaces on the production of Alt a 1 protein. PMID:25689994

  16. A transcriptomic approach highlights induction of secondary metabolism in citrus fruit in response to Penicillium digitatum infection

    PubMed Central

    2010-01-01

    Background Postharvest losses of citrus fruit due to green mold decay, caused by the fungus Penicillium digitaum, have a considerable economic impact. However, little is known about the molecular processes underlying the response of citrus fruit to P. digitatum. Results Here we describe the construction of a subtracted cDNA library enriched in citrus genes preferentially expressed in response to pathogen infection followed by cDNA macroarray hybridization to investigate gene expression during the early stages of colonization of the fruit's peel by P. digitatum. Sequence annotation of clones from the subtracted cDNA library revealed that induction of secondary and amino acid metabolisms constitutes the major response of citrus fruits to P. digitatum infection. Macroarray hybridization analysis was conducted with RNA from either control, wounded, ethylene treated or P. digitatum infected fruit. Results indicate an extensive overlap in the response triggered by the three treatments, but also demonstrated specific patterns of gene expression in response to each stimulus. Collectively our data indicate a significant presence of isoprenoid, alkaloid and phenylpropanoid biosynthetic genes in the transcriptomic response of citrus fruits to P. digitatum infection. About half of the genes that are up-regulated in response to pathogen infection are also induced by ethylene, but many examples of ethylene-independent gene regulation were also found. Two notable examples of this regulation pattern are the genes showing homology to a caffeine synthase and a berberine bridge enzyme, two proteins involved in alkaloid biosynthesis, which are among the most induced genes upon P. digitatum infection but are not responsive to ethylene. Conclusions This study provided the first global picture of the gene expression changes in citrus fruit in response to P. digitatum infection, emphasizing differences and commonalities with those triggered by wounding or exogenous ethylene treatment

  17. PESTICIDE POISONINGS REPORTED BY FLORIDA CITRUS FIELDWORKERS

    EPA Science Inventory

    In a 1981 survey of 1811 Florida citrus fieldworkers, 25 pesticide related poisoning incidents involving 29 fieldworkers were reported. Suspected poisonings were categorized into possible and confirmed poisonings, and from these reports it was possible to project an estimated 438...

  18. Considering the citrus grove of the future

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Revolutionary changes now face the Florida citrus industry as producers grapple with economically profitable production using greening susceptible material. Changing economic realties have encouraged many tree fruit industries to modify planting density, tree architecture, and training/production s...

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

    PubMed Central

    Mallick, Neelam; Khan, Rafeeq Alam

    2016-01-01

    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. PMID:27134462

  20. The role of meteorological factors in determining the annual variation of Alternaria and Cladosporium spores in the atmosphere of Palencia, 1990 1992

    NASA Astrophysics Data System (ADS)

    Herrero, B.; Fombella-Blanco, M. A.; Fernández-González, D.; Valencia-Barrera, R. M.

    1996-09-01

    A study was made of the daily content of Alternaria and Cladosporium spores in the atmosphere in Palencia city (Spain) for three consecutive years 1990 1992. Alternaria and Cladosporium represented 55% of the total identified spores, presenting an annual distributional pattern of which the maximum values were reached in summer. Multiple regression analyses showed a positive correlation between minimum temperature and Cladosporium spore concentrations, while for Alternaria there was a positive correlation with maximum temperature and a negative correlation with precipitation. Duncan's multiple range test among means of Alternaria data indicated that winds coming from a northeasterly direction were associated with significantly higher concentrations the spores.

  1. Effects of host physiology on the development of core rot, caused by alternaria alternata, in Red Delicious apples.

    PubMed

    Shtienberg, D

    2012-08-01

    Alternaria alternata is the predominant fungus involved in moldy core and core rot of Red Delicious apples. The effects of environmental conditions during bloom on moldy core and core rot, and on the need for fungicide application, were examined in 10 experiments carried out in 2007. In untreated experimental plots, typical moldy core symptoms were very common, with relatively low variability (coefficient of variation: 22.2%) among experiments; core rot incidence ranged from 2 to 26% with large variability (coefficient of variation: 90.0%) among experiments. No evidence of prevailing environmental conditions during bloom affecting the development of moldy core or core rot was detected. No effect of fungicide application (a mixture of bromuconazole + captan three times a week at bloom) on moldy core or core rot was found. A random distribution of moldy core and an occasional aggregation of core rot in the orchards were indicated from Morisita's index of dispersion (I(δ)). The hypothesis that core rot incidence is governed by host physiology and that yield load can be used as an indicator of trees' susceptibility was examined in a set of eight observations and four experiments. No correlation was found between tree yield load and moldy core, but core rot incidence was inversely related to yield load. Furthermore, irrespective of tree yield load, core rot was more abundant on large compared with small fruits. It is concluded that host physiology, rather than pathogen occurrence or environmental conditions at bloom stage, governs the development of core rot in Red Delicious apples caused by A. alternata in Israel. PMID:22624774

  2. Update on USDA advanced citrus scion selections for Indian River Citrus League

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an effort to help maintain the Florida citrus industry, the USDA US Horticultural Research Laboratory (USHRL) citrus breeding team is working to make advanced selections available for limited testing earlier and more broadly than in the past to quickly identify material with commercial potential....

  3. Ecoport Slide Shows on the Internet Related to Citrus and Citrus Diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The EcoPort website was launched in 2000 to provide a knowledge database of biodiversity. As of September 2005, the EcoPort website contained over one half million references, over 42,000 pictures and over 200 slide shows, of which 59 pertain to citrus and citrus virus and virus-like diseases. As ...

  4. Citrus County Schools Copyright Guidelines Recommended by the Citrus County Association of School Media Specialists.

    ERIC Educational Resources Information Center

    Citrus County School District, Inverness, FL.

    This document contains copyright guidelines determined appropriate for the Citrus County School System (Florida) by the Citrus County Association of School Media Specialists in May, 1992. These guidelines are based on interpretation and understanding of current copyright law as applied to education and implemented in school districts in the United…

  5. Evaluation of natural colorants and their application on citrus fruit as alternatives to citrus red II

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The poor peel color of some varieties of oranges and the hybrids, especially for early season fruits, is caused by the subtropical climate of Florida, and has resulted in the use of a red dye on the peel to improve fruit appearance and marketability. Citrus Red II (CR2), the commercial citrus color ...

  6. Freeze response of citrus and citrus-related genotypes in a Florida field planting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A test population consisting of progenies of 92 seed-source genotypes (hereafter called “parent genotypes”) of citrus and citrus relatives in the field in East-central Florida was assessed following natural freeze events in the winters of 2010 and 2011. Eight seedlings per parent genotype were plant...

  7. Functional complementation of fumonisin biosynthesis in FUM1-disrupted fusarium verticillioides by the AAL-toxin polyketide synthase gene ALT1 from Alternaria alternata f. sp. Lycopersici.

    PubMed

    Zhu, Xiangcheng; Vogeler, Chad; Du, Liangcheng

    2008-06-01

    Fumonisins and AAL-toxins are mycotoxins produced by several widespread fungal pathogens of crops. The carbon backbone of the mycotoxins originates from a highly reduced, acyclic polyketide, a C18 chain for fumonisins and a C16 chain for AAL-toxins. Fungal reduced polyketides are assembled by iterative modular polyketide synthases (PKS), and their biosynthetic mechanism is not very clear. Here, we cloned the PKS gene, ALT1, from the tomato pathogen Alternaria alternata f. sp. Lycopersici and introduced it into Fusarium verticillioides 5777, which does not produce fumonisins due to a disrupted fumonisin PKS gene, FUM1. An ALT1 transformant of strain 5777 produced fumonisin B series as well as fumonisin analogues. The results provide experimental evidence for the function of ALT1, which encodes a PKS for mycotoxin biosynthesis. The results also show that the C16-synthesizing ALT1 is able to support the C18 fumonisin biosynthesis in F. verticillioides, suggesting that the final size of the fungal reduced polyketides is not determined by the PKSs alone. Unlike other PKSs, these PKSs do not have a thioesterase/cyclase domain. The release of polyketide precursors that are covalently attached to the PKSs involves a distinct mechanism, which probably determines the structure of the final products. PMID:18435561

  8. 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 ▿ #

    PubMed Central

    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

  9. 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.

    PubMed

    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. PMID:21908674

  10. Phenylethanol promotes adhesion and biofilm formation of the antagonistic yeast Kloeckera apiculata for the control of blue mold on citrus.

    PubMed

    Pu, Liu; Jingfan, Fang; Kai, Chen; Chao-an, Long; Yunjiang, Cheng

    2014-06-01

    The yeast Kloeckera apiculata strain 34-9 is an antagonist with biological control activity against postharvest diseases of citrus fruit. In a previous study it was demonstrated that K. apiculata produced the aromatic alcohol phenylethanol. In the present study, we found that K. apiculata was able to form biofilm on citrus fruit and embed in an extracellular matrix, which created a mechanical barrier interposed between the wound surface and pathogen. As a quorum-sensing molecule, phenylethanol can promote the formation of filaments by K. apiculata in potato dextrose agar medium, whereas on the citrus fruit, the antagonist remains as yeast after being treated with the same concentration of phenylethanol. It only induced K. apiculata to adhere and form biofilm. Following genome-wide computational and experimental identification of the possible genes associated with K. apiculata adhesion, we identified nine genes possibly involved in triggering yeast adhesion. Six of these genes were significantly induced after phenylethanol stress treatment. This study provides a new model system of the biology of the antagonist-pathogen interactions that occur in the antagonistic yeast K. apiculata for the control of blue mold on citrus caused by Penicillium italicum. PMID:24479773

  11. Rootstock-scion interaction affecting citrus response to CTV infection: a proteomic view.

    PubMed

    Laino, Paolo; Russo, Maria P; Guardo, Maria; Reforgiato-Recupero, Giuseppe; Valè, Giampiero; Cattivelli, Luigi; Moliterni, Vita M C

    2016-04-01

    Citrus tristeza virus (CTV) is the causal agent of various diseases with dramatic effects on citrus crops worldwide. Most Citrus species, grown on their own roots, are symptomless hosts for many CTV isolates. However, depending on different scion-rootstock combination, CTV infection should result in distinct syndromes, being 'tristeza' the more severe one, leading to a complete decline of the susceptible plants in a few weeks. Transcriptomic analyses revealed several genes involved either in defense response, or systemic acquired resistance, as well as transcription factors and components of the phosphorylation cascades, to be differentially regulated during CTV infection in Citrus aurantifolia species. To date little is known about the molecular mechanism of this host-pathogen interaction, and about the rootstock effect on citrus response to CTV infection. In this work, the response to CTV infection has been investigated in tolerant and susceptible scion-rootstock combinations by two-dimensional gel electrophoresis (2DE). A total of 125 protein spots have been found to be differently accumulated and/or phosphorylated between the two rootstock combinations. Downregulation in tolerant plants upon CTV infection was detected for proteins involved in reactive oxygen species (ROS) scavenging and defense response, suggesting a probable acclimation response able to minimize the systemic effects of virus infection. Some of these proteins resulted to be modulated also in absence of virus infection, revealing a rootstock effect on scion proteome modulation. Moreover, the phospho-modulation of proteins involved in ROS scavenging and defense response, further supports their involvement either in scion-rootstock crosstalk or in the establishment of tolerance/susceptibility to CTV infection. PMID:26459956

  12. Intra-specific differentiation of fungal endosymbiont Alternaria longissima CLB44 using RNA secondary structure analysis and their anti-infective potential.

    PubMed

    Rao, H C Yashavantha; Satish, Sreedharamurthy

    2016-08-01

    New antimicrobial agents derived from endosymbio-tic fungi with unique and targeted mode of action are crucially rudimentary to combat multidrug-resistant infections. Most of the fungi isolated as endosymbionts show close morphological feature resemblance to plant pathogenic or free-living forms, and it is difficult to differentiate these different lifestyles. A fungal endosymbiont strain CLB44 was isolated from Combretum latifolium Blume (Combretaceae). CLB44 was then identified as Alternaria longissima based on morphological and internal transcribed spacer (ITS) intervening 5.8S rRNA gene sequence analysis. ITS2 RNA secondary structure analysis was carried out using mfold server with temperature 37 °C, and anti-infective potential was determined by MIC and disk diffusion methods. ITS2 RNA secondary structure analysis clearly distinguished endosymbiotic A. longissima CLB44 from free-living and pathogenic A. longissima members in the same monophyletic clade. Secondary metabolites produced effectively inhibited Pseudomonas aeruginosa (25 μg/ml), Escherichia coli (25 μg/ml), methicillin-resistant Staphylococcus aureus (50 μg/ml), Candida albicans (100 μg/ml), and other human pathogens. This study emerges as an innovative finding that explores newly revealed ITS2 RNAs that may be an insight as new markers for refining phylogenetic relations and to distinguish fungal endosymbionts with other free-living or pathogenic forms. A. longissima CLB44, in the emerging field of endosymbionts, will pave the way to a novel avenue in drug discovery to combat multidrug-resistant infections. The sequence data of this fungus is deposited in GenBank under the accession no. KU310611. PMID:27437708

  13. Site Plan & Site Section of Citrus Landscape (Showing Relationship ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Site Plan & Site Section of Citrus Landscape (Showing Relationship of Groves & Irrigation System to Grove Canal) - Arlington Heights Citrus Landscape, Southwestern portion of city of Riverside, Riverside, Riverside County, CA

  14. A comparison of culture and bioassay for detecting citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) causes serious crop losses in tropical and subtropical citrus production regions. Detecting Xcc is important for quarantine purposes, research and disease management. Although PCR methods are available for detecting and quantifying viable bacteria,...

  15. Effect of citrus byproducts on survival of O157:H7 and non-O157 Escherichia coli serogroups within in vitro bovine ruminal microbial fermentations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus by-products contain essential oils that possess antimicrobial activities that can exert damage to the cell wall of gram-negative bacteria. This alteration to gram-negative microbes has resulted in CBP being investigated as a potential pre-harvest pathogen intervention strategy to reduce Shig...

  16. Species limits in Diaporthe: molecular re-assessment of D. citri, D. foeniculina and D. rudis with a new species on Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Species of Diaporthe are important plant pathogens associated with a wide range of hosts throughout the world. In the present study, the species causing melanose and stem end rot diseases on Citrus spp. were revised. Morphology and molecular phylogenetic analyses of the complete nuclear ribosomal in...

  17. Localization and distribution of ‘Candidatus Liberibacter asiaticus’ in citrus and periwinkle by direct tissue blot immuno assay with an anti-OmpA polyclonal antibody

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Candidatus Liberibacter asiaticus’ (CaLas), a non-cultured member of the a-proteobacteria, is the causal agent of citrus Huanglongbing (HLB). Due to the difficulties of in vitro culture, antibodies against CaLas have not been widely used in studies of this pathogen. We have used an anti-OmpA poly...

  18. Immunochemical quantitation of airborne short ragweed, Alternaria, antigen E, and Alt-I allergens: a two-year prospective study

    SciTech Connect

    Agarwal, M.K.; Swanson, M.C.; Reed, C.E.; Yunginger, J.W.

    1983-07-01

    We conducted a 2 yr prospective study to measure atmospheric short ragweed and Alternaria allergens by RAST inhibition analysis of eluates from filter sheets exposed in air samplers. In both years ragweed pollen and Alternaria spore counts, obtained with a rotoslide sampler, correlated significantly with immunochemically measured airborne ragweed and Alternaria allergenic activity. Airborne levels of the purified allergens AgE and Alt-I were successfully quantitated; these levels correlated closely with total airborne ragweed and Alternaria allergenic activities, respectively, and also with ragweed pollen and Alternaria spore counts. Eluates from filter sheets exposed during late summer and fall produced positive wheal-and-flare skin tests in patients with fall hay fever. In both years immunochemical measurements of allergenic activity due to airborne short ragweed correlated closely with mean symptom score indices in groups of short ragweed-sensitive individuals. Measurable levels of atmospheric ragweed allergenic activity were noted before and after the ragweed pollination season, and at these times we noted small increases in mean symptom score indices in the short ragweed-sensitive groups. Thus immunochemical analyses provide important information concerning levels of environmental allergens.

  19. Hourly predictive artificial neural network and multivariate regression tree models of Alternaria and Cladosporium spore concentrations in Szczecin (Poland)

    NASA Astrophysics Data System (ADS)

    Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

    2009-11-01

    A study was made of the link between time of day, weather variables and the hourly content of certain fungal spores in the atmosphere of the city of Szczecin, Poland, in 2004-2007. Sampling was carried out with a Lanzoni 7-day-recording spore trap. The spores analysed belonged to the taxa Alternaria and Cladosporium. These spores were selected both for their allergenic capacity and for their high level presence in the atmosphere, particularly during summer. Spearman correlation coefficients between spore concentrations, meteorological parameters and time of day showed different indices depending on the taxon being analysed. Relative humidity (RH), air temperature, air pressure and clouds most strongly and significantly influenced the concentration of Alternaria spores. Cladosporium spores correlated less strongly and significantly than Alternaria. Multivariate regression tree analysis revealed that, at air pressures lower than 1,011 hPa the concentration of Alternaria spores was low. Under higher air pressure spore concentrations were higher, particularly when RH was lower than 36.5%. In the case of Cladosporium, under higher air pressure (>1,008 hPa), the spores analysed were more abundant, particularly after 0330 hours. In artificial neural networks, RH, air pressure and air temperature were the most important variables in the model for Alternaria spore concentration. For Cladosporium, clouds, time of day, air pressure, wind speed and dew point temperature were highly significant factors influencing spore concentration. The maximum abundance of Cladosporium spores in air fell between 1200 and 1700 hours.

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

    PubMed

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

    2014-04-01

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

  1. Screening antimicrobial peptides in-vitro for use in developing transgenic citrus resistant to huanglongbing and citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB, associated with Candidatus Liberibacter sp.) and Asiatic citrus canker (ACC, causal organism Xanthomonas citri subsp. citri (XCC)) are bacterial diseases that seriously threaten sustainability of the Florida citrus industry. Sweet orange and grapefruit are highly susceptible to A...

  2. Endosymbiotic microbiota of Asian Citrus Psyllid (Diaphorina citri)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The causes of huanglongbing may be induced by more than one microbial agent. Thus, we examined the microbial community in the Asian citrus psyllid (AsCP) (Diaphorina citri, Hemiptera: Psyllidae). Citrus greening is one of the most severe diseases of citrus in Asia and Africa and is caused by an uncu...

  3. Molecular analysis of citrus rust (Phyllocoptruta oleivora) populations in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phyllocoptruta olevoria (Acari: Eriophyidae) or the citrus rust mite (CRM) is one of the most economically important mite pests of citrus worldwide. CRM originated from Asia, however it is found in most citrus producing areas, such as, Brazil, Morocco and the United States. Though CRM is a major pes...

  4. Preharvest measures for postharvest improvement in marketable fresh citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker, caused by the bacterium Xanthomonas citri supsp. citri, (Xcc),was once the scourge of the Florida citrus industry from the early 1900’s on and off until the early 1990’s. It has been replaced, for the most part, by citrus greening but still continues to be a problem for Florida fres...

  5. Characterizing the citrus variety Carrizo genome through 454 shotgun sequencing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus production is of global importance both in economic impact and significance to nutrition. The number of natural citrus species appears extremely limited. The genome size is small (haploid approximately 367 Mb), arranged on 18 chromosomes. The citrus variety Carrizo, generated by a ‘Washingt...

  6. Pest management practices aimed at curtailing citrus huanglongbing disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a devastating, insect-vectored disease of citrus sometimes referred to as citrus greening disease and putatively caused by phloem-limited bacteria within the genus Candidatus Liberibacter. Citrus trees infected by this disease decline in productivity; produce misshapen, inedib...

  7. Current status of Citrus tristeza virus in Central California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Lindcove Research and Extension Center (LREC), Exeter, CA has 51 ha of citrus and is the field site and screenhouses for the University of California Citrus Clonal Protection Program (CCPP). LREC maintains a zero tolerance of Citrus tristeza virus (CTV) infected trees to protect the CCPP and re...

  8. Susceptibility of sixteen citrus genotypes to Candidatus Liberibacter asiaticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) disease is the most serious threat to citrus production worldwide and in the last decade has devastated the Florida citrus industry. HLB is associated with a phloem-limited a-proteobacter Candidatus Liberibacter asiaticus (CLas) and its insect vector the Asian citrus psyllid (Dia...

  9. Cryopreservation of citrus for long-term conservation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than 850 varieties of Citrus, Fortunella, and Citrus-related species are maintained within the USDA-ARS National Plant Germplasm System and the University of California Citrus Variety Collection. These genetic resources are held within duplicated field, screenhouse, and greenhouse collections. ...

  10. Automating the assessment of citrus canker symptoms with image analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (CC, caused by Xanthomonas citri) is a serious disease of citrus in Florida and other citrus-growing regions. Severity of symptoms can be estimated by visual rating, but there is inter- and intra-rater variation. Automated image analysis (IA) may offer a way of reducing some of ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  12. Converting citrus waste to ethanol and other co-products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conversion of citrus processing waste (CPW) generated during juice production into value added co-products is an important aspect of the juice industry as it offers a solution to waste disposal issues. Currently the practice of drying citrus waste to produce citrus pulp pellets (CPP) for use as catt...

  13. Preharvest measures for postharvest improvement in marketable fresh citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker caused by the bacterium Xanthomonas citri supsp. citri, (Xcc), was once the scourge of the Florida citrus industry from the early 1900’s on and off until the early 1990’s. It has been replaced, for the most part, by citrus greening but still continues to be a problem for Florida fresh ...

  14. Thirty years of citrus tristeza virus observations in Peru

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Peruvian citrus industry was devastated by epidemics of Citrus tristeza virus (CTV) decline (CTV-D) on sour orange rootstock between 1950 and 1965 and CTV stem pitting (SP) between 1965 and 1985. CTV-SP debilitates citrus and fruit production regardless of rootstock. Control of CTV-SP by mild st...

  15. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Duties of Citrus Administrative Committee. 905.31 Section 905.31 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING....31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus...

  16. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Duties of Citrus Administrative Committee. 905.31 Section 905.31 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING....31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus...

  17. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Duties of Citrus Administrative Committee. 905.31 Section 905.31 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING....31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus...

  18. 21 CFR 74.302 - Citrus Red No. 2.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Citrus Red No. 2. 74.302 Section 74.302 Food and... ADDITIVES SUBJECT TO CERTIFICATION Foods § 74.302 Citrus Red No. 2. (a) Identity. (1) The color additive Citrus Red No. 2 is principally 1-(2,5-dimethoxyphenylazo)-2-naphthol. (2) The following diluents may...

  19. 21 CFR 74.302 - Citrus Red No. 2.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Citrus Red No. 2. 74.302 Section 74.302 Food and... ADDITIVES SUBJECT TO CERTIFICATION Foods § 74.302 Citrus Red No. 2. (a) Identity. (1) The color additive Citrus Red No. 2 is principally 1-(2,5-dimethoxyphenylazo)-2-naphthol. (2) The following diluents may...

  20. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Duties of Citrus Administrative Committee. 905.31 Section 905.31 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING....31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus...

  1. Long term field evaluation reveals HLB resistance in Citrus relatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) is a destructive disease with no known cure. To identify sources of HLB resistance in the subfamily Aurantioideae to which citrus belongs, we conducted a six-year field trial under natural disease challenge conditions in an HLB endemic region. The study included 65 Citrus ...

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

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Citrus Red No. 2. 74.302 Section 74.302 Food and... ADDITIVES SUBJECT TO CERTIFICATION Foods § 74.302 Citrus Red No. 2. (a) Identity. (1) The color additive Citrus Red No. 2 is principally 1-(2,5-dimethoxyphenylazo)-2-naphthol. (2) The following diluents may...

  3. 21 CFR 74.302 - Citrus Red No. 2.

    Code of Federal Regulations, 2010 CFR

    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... ADDITIVES SUBJECT TO CERTIFICATION Foods § 74.302 Citrus Red No. 2. (a) Identity. (1) The color additive Citrus Red No. 2 is principally 1-(2,5-dimethoxyphenylazo)-2-naphthol. (2) The following diluents may...

  4. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Duties of Citrus Administrative Committee. 905.31 Section 905.31 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING....31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus...

  5. 21 CFR 74.302 - Citrus Red No. 2.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Citrus Red No. 2. 74.302 Section 74.302 Food and... ADDITIVES SUBJECT TO CERTIFICATION Foods § 74.302 Citrus Red No. 2. (a) Identity. (1) The color additive Citrus Red No. 2 is principally 1-(2,5-dimethoxyphenylazo)-2-naphthol. (2) The following diluents may...

  6. Evaluation of natural colorants and their application on citrus fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Warm temperatures can often result in poor peel color of some citrus varieties, especially early in the harvest season. Under these conditions, Florida oranges, temples, tangelos, and K-Early citrus fruit are allowed to be treated with Citrus Red No.2 (CR2) to help produce a more acceptable peel col...

  7. Current Situation of Citrus Huanglongbing in Guangdong, P. R. China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Guangdong Province is an important citrus production region in China. Citrus Huanglongbing (HLB, yellow shoot disease) was observed in Guangdong probably in the late 1800’s and the disease was first studied there. Since the 1990’s, citrus production in Guangdong has gradually shifted from the coasta...

  8. Intercropping of citrus and guava trees for management of Huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent studies conducted in Viet Nam by Vietnamese, Japanese and Australian scientists indicate that interplanting citrus with guava negated infestations of Asian citrus psyllid and consequently huanglongbing, a serious disease caused by a bacterium vectored by the psyllid. Young citrus interplanted...

  9. Biological Indexing of Graft Transmissible Diseases of Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  10. Conventional and transgenic resistance/tolerance to Huanglongbing in citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is severely impacting Florida citrus, and has been found in California and Texas. Citrus researchers are immersed in extensive and broad-ranging efforts to identify solutions to HLB. Previous research indicates susceptibility to HLB throughout cultivated citrus: in FL none are im...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae) vectors the bacterium Candidatus Liberibacter asiaticus, one of the causal organisms of Huanglongbing or citrus greening, a devastating disease of citrus. A eulophid parasitoid, Tamarixia radiata Waterson, was imported ...

  12. Ulvans induce resistance against plant pathogenic fungi independently of their sulfation degree.

    PubMed

    de Freitas, Mateus B; Ferreira, Luciana G; Hawerroth, Caroline; Duarte, Maria Eugênia R; Noseda, Miguel D; Stadnik, Marciel J

    2015-11-20

    The present work aimed to evaluate the defense responses induced by chemically sulfated ulvans in Arabidopsis thaliana plants against the phytopathogenic fungi Alternaria brassicicola and Colletotrichum higginsianum. Derivatives with growing sulfate content (from 20.9 to 36.6%) were prepared with SO3-pyridine complex in formamide. NMR and FTIR spectroscopic analyses confirmed the increase of sulfate groups after the chemical sulfation process. The native sulfated polysaccharide (18.9% of sulfate) and its chemically sulfated derivatives similarly reduced the severity of both pathogenic fungi infections. Collectively, our results suggest that ulvans induce resistance against both fungal pathogens independently of its sulfation degree. PMID:26344294

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

    2010-01-01

    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. PMID:20388224

  15. Does citrus leaf miner impair hydraulics and fitness of citrus host plants?

    PubMed

    Raimondo, Fabio; Trifilò, Patrizia; Gullo, Maria A Lo

    2013-12-01

    Gas exchange and hydraulic features were measured in leaves of three different Citrus species (Citrus aurantium L., Citrus limon L., Citrus  ×  paradisii Macfad) infested by Phyllocnistis citrella Staiton, with the aim to quantify the impact of this pest on leaf hydraulics and, ultimately, on plant fitness. Infested leaves were characterized by the presence on the leaf blade of typical snake-shaped mines and, in some cases, of a crumpled leaf blade. Light microscopy showed that leaf crumpling was induced by damage to the cuticular layer. In all three Citrus species examined: (a) the degree of infestation did not exceed 10% of the total surface area of infested plants; (b) control and infested leaves showed similar values of minimum diurnal leaf water potential, leaf hydraulic conductance and functional vein density; and (c) maximum diurnal values of stomatal conductance to water vapour, transpiration rate and photosynthetic rate (An) were similar in both control leaves and the green areas of infested leaves. A strong reduction of An was recorded only in mined leaf areas. Our data suggest that infestation with P. citrella does not cause conspicuous plant productivity reductions in young Citrus plants, at least not in the three Citrus species studied here. PMID:24319027

  16. Evaluation of natural colorants and their application on citrus fruit as alternatives to Citrus Red No. 2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Warm field temperatures can often result in poor peel color of some citrus varieties, especially early in the harvest season. Under these conditions, Florida oranges, temples, tangelos, and K-Early citrus fruit are allowed to be treated with Citrus Red No.2 (CR2) to help produce a more acceptable pe...

  17. Antimicrobial nanoemulsion formulation with improved penetration of foliar spray through citrus leaf cuticles to control citrus Huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is one of the most serious citrus diseases that threaten citrus industry worldwide. Because Candidatus Liberibacter asiaticus (Las) resides in citrus phloem, it is difficult to deliver an effective chemical compound into the phloem for control of HLB. In this study, a transcuticu...

  18. Betaines in fruits of Citrus genus plants.

    PubMed

    Servillo, Luigi; Giovane, Alfonso; Balestrieri, Maria Luisa; Bata-Csere, Andrea; Cautela, Domenico; Castaldo, Domenico

    2011-09-14

    Numerous compounds, many of them osmolytes, were quantified in natural juices and in frozen concentrate juices from fruits of plants of the Citrus genus. L-proline, N-methyl-L-proline (hygric acid), N,N-dimethyl-L-proline (stachydrine), 4-hydroxy-L-prolinebetaine (betonicine), 4-hydroxy-L-proline, γ-aminobutyric acid (Gaba), 3-carboxypropyltrimethylammonium (GabaBet), N-methylnicotinic acid (trigonelline), and choline in the fruit juices of yellow orange, blood orange, lemon, mandarin, bitter orange (Citrus aurantium), chinotto (Citrus myrtifolia), and grapefruit were analyzed by sensitive HPLC-ESI-tandem mass spectrometry procedure. It was found that the most represented osmolytes in the juices, that is, L-proline, stachydrine, and betonicine, can be quantified with minimal sample preparation and short analysis time (about 1 min) also by flow injection analysis (FIA) ESI-MS/MS with the same results as obtained by HPLC ESI-MS/MS. In all of the juices, discrete amounts of choline and trigonelline were present. Conversely, GabaBet was always below detection limits. Notably, N-methyl-L-proline and 4-hydroxy-L-prolinebetaine, which were discovered for the first time in the juice of bergamot (Citrus bergamia Risso et Poit), are also present in all of the citrus juices examined. PMID:21838291

  19. Exposure to Alternaria alternata in US homes is associated with asthma symptoms

    PubMed Central

    Salo, Päivi M.; Arbes, Samuel J.; Sever, Michelle; Jaramillo, Renee; Cohn, Richard D.; London, Stephanie J.; Zeldin, Darryl C.

    2007-01-01

    Background Exposure to the fungus Alternaria alternata is a risk factor for asthma. Few studies have examined Alternaria exposures in indoor environments. Objective We examined whether exposure to A alternata in US homes was associated with asthma-related outcomes. Methods The data for this study were collected as part of the National Survey of Lead and Allergens in Housing. This cross-sectional study surveyed a nationally representative sample of 831 housing units inhabited by 2456 individuals in 75 different locations throughout the United States. An interviewer-administered questionnaire obtained information on demographics, household characteristics, and occupants' health status. Exposure to A alternata was assessed by measuring concentrations of A alternata antigens in vacuumed dust samples using a polyclonal anti–A alternata antibody assay. Dust samples were collected from a bed, a sofa, or a chair, and from bedroom, living room, and kitchen floors. Results Lifetime prevalence of doctor-diagnosed asthma was 11.2%, and 6.9% of the study subjects reported active asthma symptoms in the past 12 months. The prevalence of current symptomatic asthma increased with increasing Alternaria concentrations in US homes; higher levels of A alternata antigens increased the odds of having asthma symptoms in the past year (relative to the lowest tertile, adjusted odds ratio was 1.52, 95% CI, 0.90−2.55 for the 2nd tertile; and 1.84, 95% CI, 1.18−2.85 for the 3rd tertile). Conclusion Exposure to A alternata in US homes is associated with active asthma symptoms. Clinical implications Measures that reduce indoor exposure to A alternata may help control asthma exacerbations. PMID:17030243

  20. A polyphasic approach for the characterization of endophytic Alternaria strains isolated from grapevines.

    PubMed

    Polizzotto, Rachele; Andersen, Birgitte; Martini, Marta; Grisan, Simone; Assante, Gemma; Musetti, Rita

    2012-01-01

    A polyphasic approach was set up and applied to characterize 20 fungal endophytes belonging to the genus Alternaria, recovered from grapevine in different Italian regions. Morphological, microscopical, molecular and chemical investigations were performed and the obtained results were combined in a pooled cluster analysis. Following morphological analyses, all strains were grouped according to their three-dimensional sporulation pattern on PCA and to the colony characteristics on different substrates. After DNA extraction, all strains were analyzed by RAPD-PCR and the resulting profiles were subjected to cluster analysis. The metabolites extracted from the 20 Alternaria endophytes were analyzed by a HPLC and the resulting metabolite profiles were subjected to multivariate statistic analyses. In comparison with reference 'small-spored' Alternaria species, the 20 strains were segregated into two morphological groups: one belonging to the A. arborescens species-group and a second to the A. tenuissima species-group. RAPD analysis also showed that grapevine endophytes belonged to either the A. arborescens or the A. tenuissima species-group and that they were molecularly distinct from strains belonging to A. alternata. Chemotaxonomy gave the same grouping: the grapevine endophytic strains belong to A. arborescens or A. tenuissima species-groups producing known metabolites typical of these species-groups. Interestingly, the 20 grapevine endophytes were able to produce also a number of unknown metabolites, whose characterization could be useful for a more precise segregation of the two species-groups. The results show how complementary morphological, molecular and chemical data can clarify relationships among endophyte species-groups of low morphological divergence. PMID:22123507

  1. Process development for the elucidation of mycotoxin formation in Alternaria alternata

    PubMed Central

    2011-01-01

    The black mould Alternaria alternata produces a wide diversity of mycotoxins which are of particular health concern. Since no maximum allowable limits are set for Alternaria toxins in food and feed, prevention of Alternaria infestations and mycotoxin spoilage is the only way to avoid health risks. Thus, the understanding of mycotoxin biosynthesis is essential. For that purpose, a reliable batch process in a 2 L bioreactor was established which enables the study of several parameters influencing the production of the mycotoxins alternariol (AOH), alternariol monomethylether (AME) and tenuazonic acid (TA) by A. alternata DSM 12633. Modified Czapek-Dox medium was used with glucose as carbon source and ammonium and nitrate as nitrogen sources. Consumption of carbon and nitrogen sources as well as formation of the three mycotoxins were monitored; the average data of five independent fermentations was plotted and fitted using a logistic equation with four parameters. Maximum mycotoxin concentrations of 3.49 ± 0.12 mg/L AOH, 1.62 ± 0.14 mg/L AME and 38.28 ± 0.1 mg/L TA were obtained. In this system the effect of different aeration rates (0.53 vvm-0.013 vvm) was tested which exerted a great influence on mycotoxin production. The use of the semi-synthetic Czapek-Dox medium allowed the exchange of carbon and nitrogen sources for acetate and aspartic acid. The use of acetate instead of glucose resulted in the sole production of alternariol whereas the exchange of ammonium and nitrate for aspartate enhanced the production of both AOH and AME while TA production was not affected. PMID:21970547

  2. Alternaria arborescens infection in a healthy individual and literature review of cutaneous alternariosis.

    PubMed

    Hu, Wenying; Ran, Yuping; Zhuang, Kaiwen; Lama, Jebina; Zhang, Chaoliang

    2015-02-01

    A 28-year-old man presented at our clinic with 1-month history of an ulcer covered with crust on his left anterior tibia. Based on the morphological features and molecular identification, the patient was diagnosed as cutaneous alternariosis caused by Alternaria arborescens. He was successfully cured by oral itraconazole and topical use of 0.25% liposomal amphotericin B. A review of published studies revealed 29 cases of cutaneous alternariosis. Most cases (90%) occurred in immunosuppressed patients; itraconazole (59%) and voriconazole (24%) are the most effective treatments of choices. PMID:25370461

  3. Secondary metabolites from a strain of Alternaria tenuissima Isolated from Northern Manitoba soil.

    PubMed

    Anyanwu, Chukwudi S; Sorensen, John L

    2015-01-01

    Deoxyphomalone (1), dimethyl 4-methyl-2,6-pyridinedicarboxylate (2), stemphyperylenol (3), and N-methyl-2-pyrrolidone (4) were isolated from the fermentation broth of a strain of the fungus, Alternaria tenuissima. This fungus was isolated from the soil underlying the lichen, Peltigera didactyla, which had been collected from Wapusk National Park in Northern Manitoba. The structures of the compounds were determined by comprehensive analysis of their spectroscopic data including FT-IR, 1D and 2D NMR spectroscopy and mass spectrometry; and their bioactivities were tested against E.coli cells. The taxonomic identity of the fungus was confirmed by ITS sequencing of its ribosomal DNA. PMID:25920216

  4. Perylene derivatives produced by Alternaria alternata, an endophytic fungus isolated from Laurencia species.

    PubMed

    Gao, Shu-Shan; Li, Xiao-Ming; Wang, Bin-Gui

    2009-11-01

    Two new perylene derivatives, 7-epi-8-hydroxyaltertoxin I (1) and 6-epi-stemphytriol (2), along with two known compounds stemphyperylenol (3) and altertoxin I (4) were isolated from Alternaria alternata, a marine endophytic fungus derived from an unidentified algal species of the genus Laurencia. Structures of compounds 1-4 were determined on the basis of detailed spectroscopic analysis, as well as by comparison with literature reports. The antimicrobial activities of compounds 1 and 3 against Staphylococcus aureus, Escherichia coli, and Aspergillus niger were evaluated; neither showed obvious activity. PMID:19967977

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

    PubMed

    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. PMID:26835778

  6. Noninvasive maturity detection of citrus with machine vision

    NASA Astrophysics Data System (ADS)

    Ying, Yibin; Xu, Zhenggang; Fu, Xiaping; Liu, Yande

    2004-03-01

    A computer vision system was established to explore a method for citrus maturity detection. The surface color information and the ratio of total soluble solid to titratable acid (TSS/TA) were used as maturity indexes of citrus. The spectral reflectance properties with different color were measured by UV-240 ultraviolet and visible spectrophotometer. The biggest discrepancy of gray levels between citrus pixels and background pixels was in blue component image by image background segmentation. Dynamic threshold method for background segmentation had best result in blue component image. Methods for citrus image color description were studied. The citrus spectral reflectance experiments showed that green surface and saffron surface of citrus were of highest spectral reflectance at the wavelength of 700nm, the difference between them reached to maximum, about 53%, and the image acquired at this wavelength was of more color information for maturity detection. A triple-layer feed forward network was established to map citrus maturity from the hue frequency sequence by the mean of artificial neural network. After training, the network mapper was used to detect the maturity of the test sample set, which was composed of 252 Weizhang citrus with different maturity. The identification accuracy of mature citrus reached 79.1%, that of immature citrus was 63.6%, and the mean identification accuracy was 77.8%. This study suggested that it is feasible to detect citrus maturity non-invasively by using the computer vision system and hue frequency sequence method.

  7. Effectiveness of phenolic compounds against citrus green mould.

    PubMed

    Sanzani, Simona M; Schena, Leonardo; Ippolito, Antonio

    2014-01-01

    Stored citrus fruit suffer huge losses because of the development of green mould caused by Penicillium digitatum. Usually synthetic fungicides are employed to control this disease, but their use is facing some obstacles, such public concern about possible adverse effects on human and environmental health and the development of resistant pathogen populations. In the present study quercetin, scopoletin and scoparone--phenolic compounds present in several agricultural commodities and associated with response to stresses--were firstly tested in vitro against P. digitatum and then applied in vivo on oranges cv. Navelina. Fruits were wound-treated (100 µg), pathogen-inoculated, stored and surveyed for disease incidence and severity. Although only a minor (≤13%) control effect on P. digitatum growth was recorded in vitro, the in vivo trial results were encouraging. In fact, on phenolic-treated oranges, symptoms appeared at 6 days post-inoculation (DPI), i.e., with a 2 day-delay as compared to the untreated control. Moreover, at 8 DPI, quercetin, scopoletin, and scoparone significantly reduced disease incidence and severity by 69%-40% and 85%-70%, respectively, as compared to the control. At 14 DPI, scoparone was the most active molecule. Based on the results, these compounds might represent an interesting alternative to synthetic fungicides. PMID:25153867

  8. Biogenic emissions from Citrus species in California

    NASA Astrophysics Data System (ADS)

    Fares, Silvano; Gentner, Drew R.; Park, Jeong-Hoo; Ormeno, Elena; Karlik, John; Goldstein, Allen H.

    2011-09-01

    Biogenic Volatile Organic Compounds (BVOC) emitted from plants are the dominant source of reduced carbon chemicals to the atmosphere and are important precursors to the photochemical production of ozone and secondary organic aerosols. Considering the extensive land used for agriculture, cultivated Citrus plantations may play an important role in the chemistry of the atmosphere especially in regions such as the Central Valley of California. Moreover, the BVOC emissions from Citrus species have not been characterized in detail and more species-specific inputs for regional models of BVOC emissions are needed. In this study, we measured the physiological parameters and emissions of the most relevant BVOC (oxygenated compounds, monoterpenes, and sesquiterpenes) for four predominant Citrus species planted in California ( Citrus sinensis var. 'Parent Navel', Citrus limon var. 'Meyer', Citrus reticulata var. 'W. Murcott' and 'Clementine'). We used two analytical techniques to measure a full range of BVOC emitted: Proton Transfer Reaction Mass Spectrometry (PTR-MS) and gas chromatography with mass spectrometry. Methanol, followed by acetone and acetaldehyde, were the dominant BVOC emitted from lemon and mandarin trees (basal emission rates up to 300 ng(C) g(DW) -1 h -1), while oxygenated monoterpenes, monoterpenes, and sesquiterpenes were the main BVOC emitted from orange trees (basal emission rates up to = 2500 ng(C) g(DW) -1 h -1). Light and temperature-dependent algorithms were better predictors of methanol, acetaldehyde, acetone, isoprene and monoterpenes for all the Citrus species. Whereas, temperature-dependent algorithms were better predictors of oxygenated monoterpenes, and sesquiterpenes. We observed that flowering increased emissions from orange trees by an order of magnitude with the bulk of BVOC emissions being comprised of monoterpenes, sesquiterpenes, and oxygenated monoterpenes. Chemical speciation of BVOC emissions show that the various classes of terpene

  9. Management of the Citrus Nematode, Tylenchulus semipenetrans.

    PubMed

    Verdejo-Lucas, S; McKenry, M V

    2004-12-01

    Of the many nematode species that parasitize citrus, Tylenchulus semipenetrans is the most important on a worldwide basis. Management of the citrus nematode remains problematic as no one tactic gives adequate control of the nematode. An overall management strategy must include such components as site selection, use of non-infected nursery stock, use of at lease one post-plant nematode control tactic, and careful management of other elements of the environment that may stress the trees. Nematicides continue to play a key role in management of this pest. Optimum results require careful attention to application techniques. PMID:19262822

  10. Management of the Citrus Nematode, Tylenchulus semipenetrans

    PubMed Central

    Verdejo-Lucas, S.; McKenry, M. V.

    2004-01-01

    Of the many nematode species that parasitize citrus, Tylenchulus semipenetrans is the most important on a worldwide basis. Management of the citrus nematode remains problematic as no one tactic gives adequate control of the nematode. An overall management strategy must include such components as site selection, use of non-infected nursery stock, use of at lease one post-plant nematode control tactic, and careful management of other elements of the environment that may stress the trees. Nematicides continue to play a key role in management of this pest. Optimum results require careful attention to application techniques. PMID:19262822

  11. Collection and Chemical Composition of Phloem Sap from Citrus sinensis L. Osbeck (Sweet Orange)

    PubMed Central

    Hijaz, Faraj; Killiny, Nabil

    2014-01-01

    Through utilizing the nutrient-rich phloem sap, sap feeding insects such as psyllids, leafhoppers, and aphids can transmit many phloem-restricted pathogens. On the other hand, multiplication of phloem-limited, uncultivated bacteria such as Candidatus Liberibacter asiaticus (CLas) inside the phloem of citrus indicates that the sap contains all the essential nutrients needed for the pathogen growth. The phloem sap composition of many plants has been studied; however, to our knowledge, there is no available data about citrus phloem sap. In this study, we identified and quantified the chemical components of phloem sap from pineapple sweet orange. Two approaches (EDTA enhanced exudation and centrifugation) were used to collect phloem sap. The collected sap was derivatized with methyl chloroformate (MCF), N-methyl-N- [tert-butyl dimethylsilyl]-trifluroacetamide (MTBSTFA), or trimethylsilyl (TMS) and analyzed with GC-MS revealing 20 amino acids and 8 sugars. Proline, the most abundant amino acid, composed more than 60% of the total amino acids. Tryptophan, tyrosine, leucine, isoleucine, and valine, which are considered essential for phloem sap-sucking insects, were also detected. Sucrose, glucose, fructose, and inositol were the most predominant sugars. In addition, seven organic acids including succinic, fumaric, malic, maleic, threonic, citric, and quinic were detected. All compounds detected in the EDTA-enhanced exudate were also detected in the pure phloem sap using centrifugation. The centrifugation technique allowed estimating the concentration of metabolites. This information expands our knowledge about the nutrition requirement for citrus phloem-limited bacterial pathogen and their vectors, and can help define suitable artificial media to culture them. PMID:25014027

  12. Efficacy of Chaetomium Species as Biological Control Agents against Phytophthora nicotianae Root Rot in Citrus

    PubMed Central

    Wattanachai, Pongnak; Kasem, Soytong; Poeaim, Supattra

    2015-01-01

    Thailand is one of the largest citrus producers in Southeast Asia. Pathogenic infection by Phytophthora, however, has become one of major impediments to production. This study identified a pathogenic oomycete isolated from rotted roots of pomelo (Citrus maxima) in Thailand as Phytophthora nicotianae by the internal transcribed spacer ribosomal DNA sequence analysis. Then, we examined the in vitro and in vivo effects of Chaetomium globosum, Chaetomium lucknowense, Chaetomium cupreum and their crude extracts as biological control agents in controlling this P. nicotianae strain. Represent as antagonists in biculture test, the tested Chaetomium species inhibited mycelial growth by 50~56% and parasitized the hyphae, resulting in degradation of P. nicotianae mycelia after 30 days. The crude extracts of these Chaetomium species exhibited antifungal activities against mycelial growth of P. nicotianae, with effective doses of 2.6~101.4 µg/mL. Under greenhouse conditions, application of spores and methanol extracts of these Chaetomium species to pomelo seedlings inoculated with P. nicotianae reduced root rot by 66~71% and increased plant weight by 72~85% compared to that in the control. The method of application of antagonistic spores to control the disease was simple and economical, and it may thus be applicable for large-scale, highly effective biological control of this pathogen. PMID:26539045

  13. Possibility of Alternaria toxins reduction by extrusion processing of whole wheat flour.

    PubMed

    Janić Hajnal, Elizabet; Čolović, Radmilo; Pezo, Lato; Orčić, Dejan; Vukmirović, Đuro; Mastilović, Jasna

    2016-12-15

    This study represents the first report about possibility of reduction of Alternaria toxins in wheat using the extrusion process. Effects of extrusion processing parameters - moisture content (w=16, 20, 24g/100g), feeding rate (q=15, 20, 25kg/h), and screw speed (v=300, 390, 480rpm), on reduction rate of tenuazonic acid (TeA), alternariol (AOH) and alternariol monomethyl ether (AME), in whole wheat flour were investigated. Temperature ranged between 111.1 and 160.8°C, while the absolute pressure was from 0.17 to 0.23MPa. The simultaneous influence of w and v was the most important for TeA reduction (p<0.05), while v and q were the most influential for AOH reduction (p<0.01). Level of AME reduction was mostly influenced by w and v (p<0.10). Optimal parameters for reduction of all three Alternaria toxins were as follows: w=24g/100g, q=25kg/h, v=390rpm, with a reduction of 65.6% for TeA, 87.9% for AOH and 94.5% for AME. PMID:27451248

  14. Characterization of a genotoxic impact compound in Alternaria alternata infested rice as Altertoxin II.

    PubMed

    Schwarz, Christoph; Tiessen, Christine; Kreutzer, Martin; Stark, Timo; Hofmann, Thomas; Marko, Doris

    2012-12-01

    Toxicity-guided fractionation was used to identify DNA strand breaking impact compounds in extracts obtained from rice heavily infested with the Alternaria alternata strains DSM 62006 and DSM 62010. The major genotoxic potential measured in the comet assay using human colon carcinoma cells (HT29) could be attributed to three unknown peaks, whereas the fractions containing alternariol, its monomethylether or tenuazonic acid showed no significant DNA damaging effects. According to (1)H and (13)C-NMR spectroscopy, one genotoxic impact compound was identified as Altertoxin II (ATXII). ATXII showed potent DNA damaging properties in HT29 cells with substantial induction of formamidopyrimidine DNA glycosylase (FPG)-sensitive sites. However, no effect was observed with respect to the cellular redox status, measured in the DCF assay and as total glutathione. The induction of apoptosis could be excluded as a potential reason for enhanced DNA damage. After 24 h of incubation with 1 μM ATX II, a significant increase of cells in the G(0)/G(1) phase was observed together with an inhibition of cell proliferation in the sulforhodamine B assay. Taken together, ATX II was found to contribute substantially to the genotoxic effects of complex extracts obtained from Alternaria alternata infested rice. The results demonstrate the high genotoxic potency of ATX II in human cells, underlining the necessity for further studies on the occurrence in food and its relevance for food safety. PMID:23076116

  15. Alternaria extract activates autophagy that induces IL-18 release from airway epithelial cells.

    PubMed

    Murai, Hiroki; Okazaki, Shintaro; Hayashi, Hisako; Kawakita, Akiko; Hosoki, Koa; Yasutomi, Motoko; Sur, Sanjiv; Ohshima, Yusei

    2015-09-01

    Alternaria alternata is a major outdoor allergen that causes allergic airway diseases. Alternaria extract (ALT-E) has been shown to induce airway epithelial cells to release IL-18 and thereby initiate Th2-type responses. We investigated the underlying mechanisms involved in IL-18 release from ALT-E-stimulated airway epithelial cells. Normal human bronchial epithelial cells and A549 human lung adenocarcinoma cells were stimulated with ALT-E in the presence of different inhibitors of autophagy or caspases. IL-18 levels in culture supernatants were measured by ELISA. The numbers of autophagosomes, an LC3-I to LC3-II conversion, and p62 degradation were determined by immunofluorescence staining and immunoblotting. 3-methyladenine and bafilomycin, which inhibit the formation of preautophagosomal structures and autolysosomes, respectively, suppressed ALT-E-induced IL-18 release by cells, whereas caspase 1 and 8 inhibitors did not. ALT-E-stimulation increased autophagosome formation, LC-3 conversion, and p62 degradation in airway epithelial cells. LPS-stimulation induced the LC3 conversion in A549 cells, but did not induce IL-18 release or p62 degradation. Unlike LPS, ALT-E induced airway epithelial cells to release IL-18 via an autophagy dependent, caspase 1 and 8 independent pathway. Although autophagy has been shown to negatively regulate canonical inflammasome activity in TLR-stimulated macrophages, our data indicates that this process is an unconventional mechanism of IL-18 secretion by airway epithelial cells. PMID:26032499

  16. New cytotoxic compounds of endophytic fungus Alternaria sp. isolated from Broussonetia papyrifera (L.) Vent.

    PubMed

    Zhang, Naidan; Zhang, Chunyan; Xiao, Xiao; Zhang, Qiaoyan; Huang, Baokang

    2016-04-01

    From the ethyl acetate extract of a culture of the endophytic fungus Alternaria species G7 in Broussonetia papyrifera, a new compound altertoxin IV (1) together with nine known compounds were isolated and identified by means of bioassay-guided fractionation. The structures of these compounds were established on the basis of spectroscopic methods, among which the absolute configuration of compound 1, a new tetrahydroperylenone derivative, was determined by means of X-Ray Crystallographic analysis. The isolated compounds were subjected to cytotoxic activity against three human cancer cell lines (A549, MG-63, and SMMC-7721). Compound 2 showed significant cytotoxic activities against tested cell lines, with IC50 values of 1.47, 2.11 and 7.34 μg/mL, respectively. Additionally, compound 4 also exhibited significant cytotoxic activities against cell lines MG-63 and SMMC-7721, with IC50 values of 0.53 and 2.92 μg/mL. Endophytic fungi Alternaria from B. papyrifera might be promising sources of natural bioactive and novel metabolites. PMID:27001249

  17. Alt a 15 is a new cross-reactive minor allergen of Alternaria alternata.

    PubMed

    Gabriel, M F; Postigo, I; Gutiérrez-Rodríguez, A; Suñén, E; Guisantes, J A; Fernández, J; Tomaz, C T; Martínez, J

    2016-02-01

    Alternaria alternata is one of the most common saprophytes worldwide that is clinically and epidemiologically associated with severe asthma. Therefore, the identification and characterization of all A. alternata allergens are of major clinical importance. This study describes a new cross-reactive A. alternata allergen that was officially named Alt a 15 by the official Allergen Nomenclature Subcommittee. The complete coding region for Alt a 15 was amplified using 5' and 3' rapid amplification of cDNA ends and PCR. The recombinant protein was produced in Escherichia coli as a 65-kDa fusion protein, and the protein sequence exhibits high homology with several important fungal allergens. Immunoblotting analyses revealed that IgE antibodies from A. alternata-sensitized patients (n=59) bound to rAlt a 15 with a prevalence of 10.2%. All patients who presented sIgE to rAlt a 15 were apparently poly-sensitized to A. alternata and C. lunata. The extensive cross-reactivity between A. alternata and C. lunata serine proteases was confirmed using immunoblotting inhibition assays. Overall, Alt a 15 is an important new cross-reactive allergen of A. alternata that explains some allergies to A. alternata without Alt a 1 sensitization and initial diagnostic errors for allergies to Alternaria. This molecule may improve the accuracy of the diagnosis, the understanding, and the management of IgE-mediated fungal diseases. PMID:26395961

  18. Genome sequence of a novel victorivirus identified in the phytopathogenic fungus Alternaria arborescens.

    PubMed

    Komatsu, Ken; Katayama, Yukie; Omatsu, Tsutomu; Mizutani, Tetsuya; Fukuhara, Toshiyuki; Kodama, Motoichiro; Arie, Tsutomu; Teraoka, Tohru; Moriyama, Hiromitsu

    2016-06-01

    Strains of the phytopathogenic fungus Alternaria spp. have been found to contain a variety of double-stranded RNA (dsRNA) elements indicative of mycovirus infection. Here, we report the molecular characterization of a novel dsRNA mycovirus, Alternaria arborescens victorivirus 1 (AaVV1), from A. arborescens, the tomato pathotype of A. alternata. Using next-generation sequencing of dsRNA purified from an A. arborescens strain from the United States of America, we found that the AaVV1 genome is 5203 bp in length and contains two open reading frames (ORF1 and 2) that overlap at the tetranucleotide AUGA. Proteins encoded by ORF1 and ORF2 showed significant similarities to the coat protein (CP) and the RNA-dependent RNA polymerase (RdRp), respectively, of dsRNA mycoviruses of the genus Victorivirus. Pairwise comparisons and phylogenetic analysis of the deduced amino acid sequences of both CP and RdRp indicated that AaVV1 is a member of a distinct species of the genus Victorivirus in the family Totiviridae. PMID:26923927

  19. Proteomic analysis reveals suppression of bark chitinases and proteinase inhibitors in citrus plants affected by the citrus sudden death disease.

    PubMed

    Cantú, M D; Mariano, A G; Palma, M S; Carrilho, E; Wulff, N A

    2008-10-01

    Citrus sudden death (CSD) is a disease of unknown etiology that greatly affects sweet oranges grafted on Rangpur lime rootstock, the most important rootstock in Brazilian citriculture. We performed a proteomic analysis to generate information related to this plant pathogen interaction. Protein profiles from healthy, CSD-affected and CSD-tolerant stem barks, were generated using two-dimensional gel electrophoresis. The protein spots were well distributed over a pI range of 3.26 to 9.97 and a molecular weight (MW) range from 7.1 to 120 kDa. The patterns of expressed proteins on 2-DE gels made it possible to distinguish healthy barks from CSD-affected barks. Protein spots with MW around 30 kDa and pI values ranging from 4.5 to 5.2 were down-regulated in the CSD-affected root-stock bark. This set of protein spots was identified as chitinases. Another set of proteins, ranging in pI from 6.1 to 9.6 with an MW of about 20 kDa, were also suppressed in CSD-affected rootstock bark; these were identified as miraculin-like proteins, potential trypsin inhibitors. Down-regulation of chitinases and proteinase inhibitors in CSD-affected plants is relevant since chitinases are well-known pathogenesis-related protein, and their activity against plant pathogens is largely accepted. PMID:18943454

  20. The Effects of DBCP on Citrus Root Nematode and Citrus Growth and Yield in Iraq

    PubMed Central

    Natour, R. M.; Allow, J. M.; Katcho, Z. A.

    1975-01-01

    In lraq, treatment of producing citrus trees with a 75% emulsifiable formulation of 1,2-dibromo-3-chloropropane (DBCP), applied in irrigation water at rates of 66-88 kg (a.i.)/hectare, gave excellent control of the citrus nematode (Tylenchulus semipenetrans) greatly improved tree vigor, and increased the fruit yield for at least 3 years after treatment. Applications made during the spring gave much better results than those made in the fall. PMID:19308170

  1. Transmission and Propagation of 'Candidatus Liberibacter asiaticus' by Grafting with Individual Citrus Leaves.

    PubMed

    Hilf, Mark E; Lewis, Reid S

    2016-05-01

    Huanglongbing (HLB) is a chronic, progressive decline disease in citrus associated with a systemic infection by the bacterium 'Candidatus Liberibacter asiaticus'. Transmission of the bacterium in the field is by the Asian citrus psyllid, Diaphorina citri Kuwayama. Experimental propagation of 'Ca. L. asiaticus' is done primarily by grafting pieces of bud wood from an infected plant. To produce a small-scale model system for investigation of pathogen biology, we investigated grafting single leaves from infected citrus plants as sources of inoculum for propagation of the bacterium. In total, 162 plants ranging in age from 3 to 18 months were grafted. Grafting with intact asymptomatic and HLB-symptomatic leaves resulted in 61 of 78 (78%) and 35 of 41 (85%) of the plants infected with 'Ca. L. asiaticus', respectively. Inoculum consisting of the leaf petiole only or only an inoculum tissue remnant under the bark of the receptor tree resulted in 6 of 12 (50%) and 7 of 31 (23%) infected trees, respectively. Real-time polymerase chain reaction (qPCR) assays verified the infection in plants, a majority of which developed the foliar blotchy mottle symptom considered diagnostic for HLB, while some plants also displayed the stunted, chlorotic shoots for which the disease is named. The qPCR data together with the symptoms displayed demonstrated that individual leaves from infected trees can serve as effective inoculum sources for transmission and propagation of 'Ca. L. asiaticus' via grafting. PMID:26807818

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

    PubMed

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

    2016-01-01

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

  3. Complete genome sequence of citrus huanglongbing bacterium, 'Candidatus Liberibacter asiaticus' obtained through metagenomics.

    PubMed

    Duan, Yongping; Zhou, Lijuan; Hall, David G; Li, Wenbin; Doddapaneni, Harshavardhan; Lin, Hong; Liu, Li; Vahling, Cheryl M; Gabriel, Dean W; Williams, Kelly P; Dickerman, Allan; Sun, Yijun; Gottwald, Tim

    2009-08-01

    Citrus huanglongbing is the most destructive disease of citrus worldwide. It is spread by citrus psyllids and is associated with a low-titer, phloem-limited infection by any of three uncultured species of alpha-Proteobacteria, 'Candidatus Liberibacter asiaticus', 'Ca. L. americanus', and 'Ca. L. africanus'. A complete circular 'Ca. L. asiaticus' genome has been obtained by metagenomics, using the DNA extracted from a single 'Ca. L. asiaticus'-infected psyllid. The 1.23-Mb genome has an average 36.5% GC content. Annotation revealed a high percentage of genes involved in both cell motility (4.5%) and active transport in general (8.0%), which may contribute to its virulence. 'Ca. L. asiaticus' appears to have a limited ability for aerobic respiration and is likely auxotrophic for at least five amino acids. Consistent with its intracellular nature, 'Ca. L. asiaticus' lacks type III and type IV secretion systems as well as typical free-living or plant-colonizing extracellular degradative enzymes. 'Ca. L. asiaticus' appears to have all type I secretion system genes needed for both multidrug efflux and toxin effector secretion. Multi-protein phylogenetic analysis confirmed 'Ca. L. asiaticus' as an early-branching and highly divergent member of the family Rhizobiaceae. This is the first genome sequence of an uncultured alpha-proteobacteria that is both an intracellular plant pathogen and insect symbiont. PMID:19589076

  4. A Zinc-Finger-Family Transcription Factor, AbVf19, Is Required for the Induction of a Gene Subset Important for Virulence in Alternaria brassicicola

    SciTech Connect

    Srivastava, Akhil; Ohm, Robin A.; Oxiles, Lindsay; Brooks, Fred; Lawrence, Christopher B.; Grigoriev, Igor V.; Cho, Yangrae

    2011-10-26

    Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen with a broad host range within the family Brassicaceae. It produces secondary metabolites that marginally affect virulence. Cell wall degrading enzymes (CDWE) have been considered important for pathogenesis but none of them individually have been identified as significant virulence factors in A. brassicicola. In this study, knockout mutants of a gene, AbVf19, were created and produced considerably smaller lesions than the wild type on inoculated host plants. The presence of tandem zinc-finger domains in the predicted amino acid sequence and nuclear localization of AbVf19- reporter protein suggested that it was a transcription factor. Gene expression comparisons using RNA-seq identified 74 genes being downregulated in the mutant during a late stage of infection. Among the 74 downregulated genes, 28 were putative CWDE genes. These were hydrolytic enzyme genes that composed a small fraction of genes within each family of cellulases, pectinases, cutinases, and proteinases. The mutants grew slower than the wild type on an axenic medium with pectin as a major carbon source. This study demonstrated the existence and the importance of a transcription factor that regulates a suite of genes that are important for decomposing and utilizing plant material during the late stage of plant infection.

  5. Pathogen intelligence

    PubMed Central

    Steinert, Michael

    2014-01-01

    Different species inhabit different sensory worlds and thus have evolved diverse means of processing information, learning and memory. In the escalated arms race with host defense, each pathogenic bacterium not only has evolved its individual cellular sensing and behavior, but also collective sensing, interbacterial communication, distributed information processing, joint decision making, dissociative behavior, and the phenotypic and genotypic heterogeneity necessary for epidemiologic success. Moreover, pathogenic populations take advantage of dormancy strategies and rapid evolutionary speed, which allow them to save co-generated intelligent traits in a collective genomic memory. This review discusses how these mechanisms add further levels of complexity to bacterial pathogenicity and transmission, and how mining for these mechanisms could help to develop new anti-infective strategies. PMID:24551600

  6. The Efficacy and Underlying Mechanism of Sulfone Derivatives Containing 1,3,4-oxadiazole on Citrus Canker.

    PubMed

    Li, Pei; Ma, Yuhua; Zhou, Junliang; Luo, Hui; Yan, Jiawen; Mao, Yongya; Wang, Zhuang

    2015-01-01

    The objectives of the current study were to isolate and identify the pathogen responsible for citrus canker and investigate the efficacy of sulfone derivatives containing 1,3,4-oxadiazole moiety on controlling citrus canker caused by Xanthomonas citri subsp. citri (Xcc) under in vitro and field conditions. In an in vitro study, we tested eight sulfone derivatives against Xcc and the results demonstrated that compound 3 exhibited the best antibacterial activity against Xcc, with a half-maximal effective concentration (EC50) value of 1.23 μg/mL, which was even better than those of commercial bactericides Kocide 3000 (58.21 μg/mL) and Thiodiazole copper (77.04 μg/mL), respectively. Meanwhile, under field experiments, compound 3 treatments demonstrated the highest ability to reduce the disease of citrus canker in leaves and fruits in two different places relative to an untreated control as well as the commercial bactericides Kocide 3000 and Thiodiazole copper. Meanwhile, compound 3 could stimulate the increase in peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia lyase (PAL) activities in the navel orange leaves, causing marked enhancement of plant resistance against citrus canker. Moreover, compound 3 could damage the cell membranes, destruct the biofilm formation, inhibit the production of extracellular polysaccharide (EPS), and affect the cell membrane permeability to restrain the growth of the bacteria. PMID:26247929

  7. Characterization of Alternaria isolates from the infectoria species-group and a new taxon from Arrhenatherum, Pseudoalternaria arrhenatheria sp. nov

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The infectoria species-group within the genus Alternaria was originally conceived by Simmons in 1993 and was based upon common morphological characteristics that included the development of conidial chains with primary, secondary, and tertiary branching resulting in substantial three-dimensional com...

  8. Molecular characterization and detection of mutations associated with resistance to succinate dehydrogenase inhibiting (SDHI) fungicides in Alternaria solani

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Early blight, caused by Alternaria solani, is an economically important foliar disease of potato in several production areas of the United States. Few potato cultivars possess resistance to early blight, therefore, the application of fungicides is a primary means of achieving disease control. Previo...

  9. Effects of Alternaria destruens, Glyphosate, and Ammonium Sulfate Individually and Integrated for Control of Dodder (Cuscuta pentagona)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dodder is a serious weed problem in several crops. Its minutely sized, easily dispersed, and highly viable seed makes it difficult to control. Alternaria destruens is the active ingredient in a registered bioherbicide for control of dodder species. In greenhouse studies, the following treatments ...

  10. Survey of Alternaria toxin contamination in food from the German market, using a rapid HPLC-MS/MS approach.

    PubMed

    Hickert, Sebastian; Bergmann, Marian; Ersen, Seyma; Cramer, Benedikt; Humpf, Hans-Ulrich

    2016-02-01

    A HPLC-MS/MS-based method for the quantification of nine mycotoxins produced by fungi of the genus Alternaria in various food matrices was developed. The method relies on a single-step extraction, followed by dilution of the raw extract and direct analysis. In combination with an analysis time per sample of 12 min, the sample preparation is cost-effective and easy to handle. The method covers alternariol (AOH), alternariol monomethyl ether (AME), tenuazonic acid (TeA), altenuene (ALT), iso-altenuene (isoALT), tentoxin (TEN), altertoxin-I (ATX-I), and the AAL toxins TA1 and TA2. Some Alternaria toxins which are either not commercially available or very expensive, namely AOH, AME, ALT, isoALT, and ATX-I, were isolated as reference compounds from fungal cultures. The method was extensively validated for tomato products, bakery products, sunflower seeds, fruit juices, and vegetable oils. AOH, AME, TeA, and TEN were found in quantifiable amounts and 92.1% of all analyzed samples (n = 96) showed low level contamination with one or more Alternaria toxins. Based on the obtained results, the average daily exposure to Alternaria toxins in Germany was calculated. PMID:26408172

  11. Resistance and tolerance to huanglongbing in citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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-i...

  12. Huanglongbing resistance and tolerance in citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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-i...

  13. Asian citrus psyllid - biology and seasonal ecology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The seasonal ecology of Diaphorina citri was investigated in a non-irrigated citrus grove of mature orange trees beginning January 2005 in east central Florida. No insecticides were applied during the study. Predators including lady beetles, lacewings and syrphid flies were observed during the stud...

  14. Ecology of the Asian citrus pysllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  15. Assessment of Stubborn Disease Incidence in Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus stubborn disease (CSD) has been a problem in California for over 90 years, yet, methods for rapidly detecting its causal agent, Spiroplasma citri, for use in estimating disease incidence have not been optimized. Two 8 ha blocks within two commercial groves were sampled in July and August, 20...

  16. Asian Citrus Psyllid, Genetic Basis of Immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used a genomics approach to identify some of the genetic bases of D. citri immunity, identifying in particular genes associated with environmental and biological stresses. Only a few insecticides are being used to manage the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae), to...

  17. 2006 University Citrus Pest Management Guide: Tristeza

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is a major cause of the decline and eventual death of trees on sour orange rootstocks. Initially, affected trees have small leaves and twig dieback. Diseased trees often produce a crop of very small fruit. Eventually, large limbs die back and the tree gradually declines...

  18. Founder lines for improved citrus biotechnology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  19. Assessment of Stubborn Disease Incidence in Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus stubborn disease, caused by Spiroplasma Citri, has occured in California for more than 90 years, however, detection methods for estimating disease incidence have not been well developed. Two 8 ha plots in Kern Co. CA were established and sampled in July and August, 2006. Different tissues o...

  20. Reasons for inconsistent citrus canker control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop losses from citrus canker in 2014 for Hamlin due to premature fruit drop, or for grapefruit from unacceptable severity of fruit lesions, were highly variable due to periodic rains that in certain locations were coincident with grapefruit flushes in February-March or with early Hamlin fruit deve...

  1. Effect of genotype and environment on citrus juice carotenoid content.

    PubMed

    Dhuique-Mayer, Claudie; Fanciullino, Anne-Laure; Dubois, Cecile; Ollitrault, Patrick

    2009-10-14

    A selection of orange and mandarin varieties belonging to the same Citrus accession and cultivated in Mediterranean (Corsica), subtropical (New Caledonia), and tropical areas (principally Tahiti) were studied to assess the effect of genotype and environmental conditions on citrus juice carotenoid content. Juices from three sweet orange cultivars, that is, Pera, Sanguinelli, and Valencia ( Citrus sinensis (L.) Osbeck), and two mandarin species ( Citrus deliciosa Ten and Citrus clementina Hort. ex Tan), were analyzed by HPLC using a C(30) column. Annual carotenoid content variations in Corsican fruits were evaluated. They were found to be very limited compared to variations due to varietal influences. The statistical analysis (PCA, dissimilarity tree) results based on the different carotenoid compounds showed that citrus juice from Corsica had a higher carotenoid content than citrus juices from tropical origins. The tropical citrus juices were clearly differentiated from citrus juices from Corsica, and close correlations were obtained between beta-cryptoxanthin and phytoene (r = 0.931) and beta-carotene and phytoene (r = 0.918). More broadly, Mediterranean conditions amplified interspecific differentiation, especially by increasing the beta-cryptoxanthin and cis-violaxanthin content in oranges and beta-carotene and phytoene-phytofluene content in mandarins. Thus, at a quantitative level, environmental conditions also had a major role in determining the levels of carotenoids of nutritional interest, such as the main provitamin A carotenoids in citrus juice (beta-cryptoxanthin and beta-carotene). PMID:19807162

  2. Comparative in vitro toxicity of grape- and citrus-farm dusts.

    PubMed

    Vallyathan, Val; Pack, Donna; Leonard, Steve; Lawson, Robert; Schenker, Marc; Castranova, Vince

    2007-01-15

    Agricultural workers are exposed to a variety of airborne dusts, including crystalline silica and other inorganic minerals. This study was designed to characterize the organic and inorganic components of agricultural dusts in California grape- and citrus-farm fields and to compare their cytotoxicity using in vitro toxicity bioassays as predictors of pathogenicity. Aerosolized dusts collected from farm fields were characterized by scanning-electron-microscopic energy-dispersive x-ray analysis, x-ray diffraction, trace metal analysis by plasma emission spectroscopy, and surface area measurements. As indicators of cytotoxicity, cell viability, release of alveolar enzymes activities (lactate dehydrogenase, N-acetyl glucosaminidase), production of reactive oxygen species (ROS), such as H2O2 and hydroxyl radical (OH), and lipid peroxidation were monitored after exposure of cells to grape- and citrus-farm dusts or inorganic components of these dusts. In addition, activation of nuclear factor kappa B and activator protein-1 were evaluated at the peak time for response of 36 h postexposure. All toxicity studies were done in comparison with crystalline silica of similar particle size and diameter using the same mass concentrations as farm dusts. The results showed that inorganic minerals in the aerosolized farm dust fractions were mostly composed of aluminum silicates, crystalline silica, and free iron. Crystalline silica used in these studies was more cytotoxic than grape- and citrus-farm dusts. However, in general, citrus farm dust exhibited the greatest ability to generate ROS and induce lipid peroxidation. These results support human epidemiologic studies, reporting an increased incidence of pulmonary fibrosis in farm workers, by documenting the potential of farm dusts to induce oxidative stress and initiate disease development. PMID:17365569

  3. Transmission rates of ‘Ca. Liberibacter asiaticus’ by Asian citrus psyllid are enhanced by the presence and developmental stage of citrus flush

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asian citrus psyllid (ACP) transmits a bacterium ‘Candidatus Liberibacter asiaticus’ (CLas) putatively responsible for a devastating citrus disease known as Asiatic huanglongbing (HLB) (= citrus greening disease). The psyllid and disease have invaded many citrus-growing regions around the world incl...

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

    PubMed

    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. PMID:26447635

  5. Compatibility of Isaria fumosorosea (Hypocreales: Cordycipitaceae) Blastospores with Agricultural Chemicals Used for Management of the Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae).

    PubMed

    Avery, Pasco B; Pick, David A; Aristizábal, Luis F; Kerrigan, James; Powell, Charles A; Rogers, Michael E; Arthurs, Steven P

    2013-01-01

    Biorational insecticides are being increasingly emphasized for inclusion in integrated pest management programs for invasive insects. The entomopathogenic fungus, Isaria fumosorosea, can be used to help manage the Asian citrus psyllid with minimal impact on beneficial arthropods, but its effectiveness may be compromised by agrochemicals used to control concurrent arthropod pests and diseases. We evaluated the compatibility of I. fumosorosea blastospores with a range of spray oils and copper-based fungicides registered for use in citrus groves. Results of laboratory and greenhouse tests showed a range of responses of the fungus to the different materials, including compatibility and incompatibility. Overall, I. fumosorosea growth in vitro was reduced least by petroleum-based materials and most by botanical oils and borax, and some of the copper-based fungicides, suggesting that tank mixing of I. fumosorosea with these latter products should be avoided. However, equivalent negative effects of test materials on fungal pathogenicity were not always observed in tests with adult psyllids. We hypothesize that some oils enhanced adherence of blastospores to the insect cuticle, overcoming negative impacts on germination. Our data show that care should be taken in selecting appropriate agrochemicals for tank-mixing with commercial formulations of entomopathogenic fungi for management of citrus pests. The prospects of using I. fumosorosea for managing the invasive Asian citrus psyllid and other citrus pests are discussed. PMID:26462531

  6. Compatibility of Isaria fumosorosea (Hypocreales: Cordycipitaceae) Blastospores with Agricultural Chemicals Used for Management of the Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae)

    PubMed Central

    Avery, Pasco B.; Pick, David A.; Aristizábal, Luis F.; Kerrigan, James; Powell, Charles A.; Rogers, Michael E.; Arthurs, Steven P.

    2013-01-01

    Biorational insecticides are being increasingly emphasized for inclusion in integrated pest management programs for invasive insects. The entomopathogenic fungus, Isaria fumosorosea, can be used to help manage the Asian citrus psyllid with minimal impact on beneficial arthropods, but its effectiveness may be compromised by agrochemicals used to control concurrent arthropod pests and diseases. We evaluated the compatibility of I. fumosorosea blastospores with a range of spray oils and copper-based fungicides registered for use in citrus groves. Results of laboratory and greenhouse tests showed a range of responses of the fungus to the different materials, including compatibility and incompatibility. Overall, I. fumosorosea growth in vitro was reduced least by petroleum-based materials and most by botanical oils and borax, and some of the copper-based fungicides, suggesting that tank mixing of I. fumosorosea with these latter products should be avoided. However, equivalent negative effects of test materials on fungal pathogenicity were not always observed in tests with adult psyllids. We hypothesize that some oils enhanced adherence of blastospores to the insect cuticle, overcoming negative impacts on germination. Our data show that care should be taken in selecting appropriate agrochemicals for tank-mixing with commercial formulations of entomopathogenic fungi for management of citrus pests. The prospects of using I. fumosorosea for managing the invasive Asian citrus psyllid and other citrus pests are discussed. PMID:26462531

  7. Physical Changes in Satsuma Mandarin Leaf after Infection of Elsinoë fawcettii Causing Citrus Scab Disease

    PubMed Central

    Paudyal, Dilli Prasad; Hyun, Jae-Wook

    2015-01-01

    Citrus scab disease is one of the destructive diseases that reduce the value of fruit for the fresh market. We analyzed the process of symptom development after infection with scab pathogen Elsinoë fawcettii in the susceptible satsuma mandarin leaves to observe the structural modification against pathogen. The cuticle and epidermal cells along with 3–5 layers of mesophyll tissue were degraded 1–2 days post inoculation. Surrounding peripheral cells of degraded tissues grew rapidly and then enveloped the necrotic area along with the growing conidia. Cross sections through the lesion revealed hyphal colonization in epidermis and mesophyll tissues. In response to the pathogen colonization, host cell walls were lignified, inner cells were rapidly compartmentalized and a semi-circular boundary was formed that separated the infected region from the non-infected region, and finally prevented the intercellular pathogen spread. PMID:26674386

  8. Citrus alongside the sinking wreckage of MV Pacific Star in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Citrus alongside the sinking wreckage of MV Pacific Star in the Pacific Ocean. Pacific Star's captain used his vessel to ram the cutter after he was ordered to stop and submit to inspection by a boarding team. Citrus was not seriously damaged in the collision. U.S. Coast Guard personnel recovered a large amount of marijuana from the wreckage - U.S. Coast Guard Cutter CITRUS, Coos Bay, Coos County, OR

  9. Alternaria alternata allergens: Markers of exposure, phylogeny and risk of fungi-induced respiratory allergy.

    PubMed

    Gabriel, Marta F; Postigo, Idoia; Tomaz, Cândida T; Martínez, Jorge

    2016-01-01

    Alternaria alternata spores are considered a well-known biological contaminant and a very common potent aeroallergen source that is found in environmental samples. The most intense exposure to A. alternata allergens is likely to occur outdoors; however, Alternaria and other allergenic fungi can colonize in indoor environments and thereby increase the fungal aeroallergen exposure levels. A consequence of human exposure to fungal aeroallergens, sensitization to A. alternata, has been unequivocally associated with increased asthma severity. Among allergenic proteins described in this fungal specie, the major allergen, Alt a 1, has been reported as the main elicitor of airborne allergies in patients affected by a mold allergy and considered a marker of primary sensitization to A. alternata. Moreover, A. alternata sensitization seems to be a triggering factor in the development of poly-sensitization, most likely because of the capability of A. alternata to produce, in addition to Alt a 1, a broad and complex array of cross-reactive allergens that present homologs in several other allergenic sources. The study and understanding of A. alternata allergen information may be the key to explaining why sensitization to A. alternata is a risk factor for asthma and also why the severity of asthma is associated to this mold. Compared to other common environmental allergenic sources, such as pollens and dust mites, fungi are reported to be neglected and underestimated. The rise of the A. alternata allergy has enabled more research into the role of this fungal specie and its allergenic components in the induction of IgE-mediated respiratory diseases. Indeed, recent research on the identification and characterization of A. alternata allergens has allowed for the consideration of new perspectives in the categorization of allergenic molds, assessment of exposure and diagnosis of fungi-induced allergies. PMID:26826364

  10. Substrates and enzyme activities related to biotransformation of resveratrol from phenylalanine by Alternaria sp. MG1.

    PubMed

    Zhang, Jinhua; Shi, Junling; Liu, Yanlin

    2013-12-01

    To identify the substrates and enzymes related to resveratrol biosynthesis in Alternaria sp. MG1, different substrates were used to produce resveratrol, and their influence on resveratrol production was analyzed using high performance liquid chromatography (HPLC). Formation of resveratrol and related intermediates was identified using mass spectrum. During the biotransformation, activities of related enzymes, including phenylalanine ammonia-lyase (PAL), trans-cinnamate 4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL), were analyzed and tracked. The reaction system contained 100 mL 0.2 mol/L phosphate buffer (pH 6.5), 120 g/L Alternaria sp. MG1 cells, 0.1 g/L MgSO₄, and 0.2 g/L CaSO₄ and different substrates according to the experimental design. The biotransformation was carried out for 21 h at 28 °C and 120 rpm. Resveratrol formation was identified when phenylalanine, tyrosine, cinnamic acid, and p-coumaric acid were separately used as the only substrate. Accumulation of cinnamic acid, p-coumaric acid, and resveratrol and the activities of PAL, C4H, and 4CL were identified and changed in different trends during transformation with phenylalanine as the only substrate. The addition of carbohydrates and the increase of phenylalanine concentration promoted resveratrol production and yielded the highest value (4.57 μg/L) when 2 g/L glucose, 1 g/L cyclodextrin, and phenylalanine (4.7 mmol/L) were used simultaneously. PMID:24068334

  11. Yield loss assessment due to Alternaria blight and its management in linseed.

    PubMed

    Singh, R B; Singh, H K; Parmar, Arpita

    2014-04-01

    Field experiments were conducted during 2010-11 and 2011-12 to assess the yield losses due to Alternaria blight disease caused by Alternaria lini and A. linicola in recently released cultivars and their management with the integration of Trichoderma viride, fungicides and plant extract. Disease severity on leaves varied from 41.07% (Parvati) to 65.01% (Chambal) while bud damage per cent ranged between 23.56% (Shekhar) to 46.12% (T-397), respectively in different cultivars. Maximum yield loss of 58.44% was recorded in cultivar Neelum followed by Parvati (55.56%), Meera (55.56%) and Chambal (51.72%), respectively while minimum loss was recorded in Kiran (19.99%) and Jeevan (22.22%). Minimum mean disease severity (19.47%) with maximum disease control (69.74%) was recorded with the treatment: seed treatment (ST) with vitavax power (2 g kg(-1) seed) + 2 foliar sprays (FS) of Saaf (a mixture of carbendazim+mancozeb) 0.2% followed by ST with Trichoderma viride (4g kg(-1) seed) + 2 FS of Saaf (0.2%). Minimum bud damage (13.75%) with maximum control (60.94%) was recorded with treatment of ST with vitavax power+2 FS of propiconazole (0.2%). Maximum mean seed yield (1440 kg ha(-1)) with maximum net return (Rs. 15352/ha) and benefit cost ratio (1:11.04) was obtained with treatment ST with vitavax power + 2 FS of Neem leaf extract followed by treatment ST with vitavax power+2 FS of Saaf (1378 kg ha(-1)). PMID:25911838

  12. Field Evaluation of Plant Defense Inducers for the Control of Citrus Huanglongbing.

    PubMed

    Li, Jinyun; Trivedi, Pankaj; Wang, Nian

    2016-01-01

    Huanglongbing (HLB) is currently the most economically devastating disease of citrus worldwide and no established cure is available. Defense inducing compounds are able to induce plant resistance effective against various pathogens. In this study the effects of various chemical inducers on HLB diseased citrus were evaluated in four groves (three with sweet orange and one with mandarin) in Florida (United States) for two to four consecutive growing seasons. Results have demonstrated that plant defense inducers including β-aminobutyric acid (BABA), 2,1,3-benzothiadiazole (BTH), and 2,6-dichloroisonicotinic acid (INA), individually or in combination, were effective in suppressing progress of HLB disease. Ascorbic acid (AA) and the nonmetabolizable glucose analog 2-deoxy-D-glucose (2-DDG) also exhibited positive control effects on HLB. After three or four applications for each season, the treatments AA (60 to 600 µM), BABA (0.2 to 1.0 mM), BTH (1.0 mM), INA (0.1 mM), 2-DDG (100 µM), BABA (1.0 mM) plus BTH (1.0 mM), BTH (1.0 mM) plus AA (600 µM), and BTH (1.0 mM) plus 2-DDG (100 µM) slowed down the population growth in planta of 'Candidatus Liberibacter asiaticus', the putative pathogen of HLB and reduced HLB disease severity by approximately 15 to 30% compared with the nontreated control, depending on the age and initial HLB severity of infected trees. These treatments also conferred positive effect on fruit yield and quality. Altogether, these findings indicate that plant defense inducers may be a useful strategy for the management of citrus HLB. PMID:26390185

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

    PubMed

    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 (P<0.05). Many genes related to virulence, especially genes involved in the type III secretion system and effectors, are affected by positive selection, further highlighting the contribution of positive selection to the evolution of citrus 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. PMID:25689023

  14. Discrimination of Citrus reticulata Blanco and Citrus reticulata 'Chachi' by gas chromatograph-mass spectrometry based metabolomics approach.

    PubMed

    Duan, Li; Guo, Long; Dou, Li-Li; Zhou, Chang-Lin; Xu, Feng-Guo; Zheng, Guo-Dong; Li, Ping; Liu, E-Hu

    2016-12-01

    Citri Reticulatae Pericarpium, mainly including the pericarp of Citrus reticulata Blanco and the pericarp of Citrus reticulata 'Chachi', has been consumed daily as food and dietary supplement for centuries. In this study, GC-MS based metabolomics was employed to compare comprehensively the volatile constituents in Citrus reticulata Blanco and Citrus reticulata 'Chachi'. Principal component analysis and orthogonal partial least squares discrimination analysis indicated that samples could be distinguished effectively from one another. Fifteen metabolites were finally identified for use as chemical markers in discrimination of Citri Reticulatae Pericarpium samples. The antimicrobial activity against Gram-negative and Gram-positive bacteria of the volatile oil from Citrus reticulata Blanco and Citrus reticulata 'Chachi' was investigated preliminarily. PMID:27374515

  15. Citrus Flavonoids as Regulators of Lipoprotein Metabolism and Atherosclerosis.

    PubMed

    Mulvihill, Erin E; Burke, Amy C; Huff, Murray W

    2016-07-17

    Citrus flavonoids are polyphenolic compounds with significant biological properties. This review summarizes recent advances in understanding the ability of citrus flavonoids to modulate lipid metabolism, other metabolic parameters related to the metabolic syndrome, and atherosclerosis. Citrus flavonoids, including naringenin, hesperitin, nobiletin, and tangeretin, have emerged as potential therapeutics for the treatment of metabolic dysregulation. Epidemiological studies reveal an association between the intake of citrus flavonoid-containing foods and a decreased incidence of cardiovascular disease. Studies in cell culture and animal models, as well as a limited number of clinical studies, reveal the lipid-lowering, insulin-sensitizing, antihypertensive, and anti-inflammatory properties of citrus flavonoids. In animal models, supplementation of rodent diets with citrus flavonoids prevents hepatic steatosis, dyslipidemia, and insulin resistance primarily through inhibition of hepatic fatty acid synthesis and increased fatty acid oxidation. Citrus flavonoids blunt the inflammatory response in metabolically important tissues including liver, adipose, kidney, and the aorta. The mechanisms underlying flavonoid-induced metabolic regulation have not been completely established, although several potential targets have been identified. In mouse models, citrus flavonoids show marked suppression of atherogenesis through improved metabolic parameters as well as through direct impact on the vessel wall. Recent studies support a role for citrus flavonoids in the treatment of dyslipidemia, insulin resistance, hepatic steatosis, obesity, and atherosclerosis. Larger human studies examining dose, bioavailability, efficacy, and safety are required to promote the development of these promising therapeutic agents. PMID:27146015

  16. Contextual view showing northeastern eucalyptus windbreak and portion of citrus ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view showing northeastern eucalyptus windbreak and portion of citrus orchard. Camera facing 118" east-southeast. - Goerlitz House, 9893 Highland Avenue, Rancho Cucamonga, San Bernardino County, CA

  17. Molecular characterization and detection of mutations associated with resistance to succinate dehydrogenase-inhibiting fungicides in Alternaria solani.

    PubMed

    Mallik, I; Arabiat, S; Pasche, J S; Bolton, M D; Patel, J S; Gudmestad, N C

    2014-01-01

    Early blight, caused by Alternaria solani, is an economically important foliar disease of potato in several production areas of the United States. Few potato cultivars possess resistance to early blight; therefore, the application of fungicides is the primary means of achieving disease control. Previous work in our laboratory reported resistance to the succinate dehydrogenase-inhibiting (SDHI) fungicide boscalid in this plant pathogen with a concomitant loss of disease control. Two phenotypes were detected, one in which A. solani isolates were moderately resistant to boscalid, the other in which isolates were highly resistant to the fungicide. Resistance in other fungal plant pathogens to SDHI fungicides is known to occur due to amino acid exchanges in the soluble subunit succinate dehydrogenase B (SdhB), C (SdhC), and D (SdhD) proteins. In this study, the AsSdhB, AsSdhC, and AsSdhD genes were analyzed and compared in sensitive (50% effective concentration [EC50] < 5 μg ml(-1)), moderately resistant (EC50 = 5.1 to 20 μg ml(-1)), highly resistant (EC50 = 20.1 to 100 μg ml(-1)), and very highly resistant (EC50 > 100 μg ml(-1)) A. solani isolates. In total, five mutations were detected, two in each of the AsSdhB and AsSdhD genes and one in the AsSdhC gene. The sequencing of AsSdhB elucidated point mutations cytosine (C) to thymine (T) at nucleotide 990 and adenine (A) to guanine (G) at nucleotide 991, leading to an exchange from histidine to tyrosine (H278Y) or arginine (H278R), respectively, at codon 278. The H278R exchange was detected in 4 of 10 A. solani isolates moderately resistant to boscalid, exhibiting EC50 values of 6 to 8 μg ml(-1). Further genetic analysis also confirmed this mutation in isolates with high and very high EC50 values for boscalid of 28 to 500 μg ml(-1). Subsequent sequencing of AsSdhC and AsSdhD genes confirmed the presence of additional mutations from A to G at nucleotide position 490 in AsSdhC and at nucleotide position 398 in the As

  18. Quantitative real-time PCR for detection and identification of Candidatus Liberibacter species associated with citrus huanglongbing.

    PubMed

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

    2006-07-01

    Citrus huanglongbing (HLB, ex greening) is one of the most serious diseases of citrus. Different forms of the disease are caused by different Candidatus Liberobacter species, Candidatus Liberibacter asiaticus (Las), Ca. L. africanus (Laf) and Ca. L. americanus (Lam). The pathogen is transmitted by psyllid insects and by budding with contaminated plant materials. The vector psyllid Diaphorina citri can transmit both Las and Lam. Establishment of this vector into Florida, reports of Lam and Las in Brazil in 2004, and recent confirmation of HLB in Florida in September 2005 is of great concern to the citrus industry. Research on HLB has been hampered by the unculturable nature of the causal bacterium in artificial media. It has also been difficult to detect and identify the pathogens, possibly because of low concentration and uneven distribution in host plants and vector psyllids. In this study, we developed quantitative TaqMan PCR using 16S rDNA-based TaqMan primer-probe sets specific to the different Ca. Liberobacter spp. An additional primer-probe set based on plant cytochrome oxidase (COX) was used as a positive internal control to assess the quality of the DNA extracts. The assays do not cross-react with other pathogens or endophytes commonly resident in citrus plants, and are very sensitive. HLB pathogen DNA was successfully amplified from the equivalent of 20 ng of midrib tissue from symptomatic leaves. The consistent results of the assays with DNA extracted from plants infected by various Ca. Liberibacter species grown in greenhouses and in the field demonstrated a degree of reproducibility for these TaqMan assays. Inhibitors of the PCR that are frequently present in plant extracts did not affect the assay results. The population of the pathogens was estimated to be 5 x 10(7) and 2 x 10(6) cells/g of fresh midribs of symptomatic sweet orange leaves infected by Las and Lam, respectively. The ratio of pathogen DNA to host plant DNA was estimated by to be 1

  19. Cyclic Lipopeptides from Bacillus subtilis ABS–S14 Elicit Defense-Related Gene Expression in Citrus Fruit

    PubMed Central

    Waewthongrak, Waewruedee; Leelasuphakul, Wichitra; McCollum, Greg

    2014-01-01

    Effects of cyclic lipopeptides (CLPs) obtained from Bacillus subtilis ABS-S14 on eliciting defense-related gene transcription and activity of defense-related enzymes; glucanase (GLU), chitinase (CHI), peroxidase (POX) and lipoxygenase (LOX) in Citrus sinensis cv. Valencia fruit were determined. The maximum level of GLU transcripts induced in fruit treated with fengycin was significantly greatest among treatments at 48 h. Surfactin enhanced the LOX and POX transcripts. In parallel, corresponding enzyme activities were correlated with changes in gene expression observed in fruit inoculated with Penicillium digitatum following treatment with individual CLPs. Synergistic effects of fengycin and iturin A, fengycin and surfactin were shown in gene transcript of GLU and CHI, respectively, and surfactin induced POX and LOX gene expression of citrus flavedo without pathogen infection. These results suggest that fengycin and surfactin act as elicitors of defense-related gene expression in “Valencia” fruit following infection. PMID:25329301

  20. Cyclic LIPopeptides from Bacillus subtilis ABS-S14 elicit defense-related gene expression in citrus fruit.

    PubMed

    Waewthongrak, Waewruedee; Leelasuphakul, Wichitra; McCollum, Greg

    2014-01-01

    Effects of cyclic lipopeptides (CLPs) obtained from Bacillus subtilis ABS-S14 on eliciting defense-related gene transcription and activity of defense-related enzymes; glucanase (GLU), chitinase (CHI), peroxidase (POX) and lipoxygenase (LOX) in Citrus sinensis cv. Valencia fruit were determined. The maximum level of GLU transcripts induced in fruit treated with fengycin was significantly greatest among treatments at 48 h. Surfactin enhanced the LOX and POX transcripts. In parallel, corresponding enzyme activities were correlated with changes in gene expression observed in fruit inoculated with Penicillium digitatum following treatment with individual CLPs. Synergistic effects of fengycin and iturin A, fengycin and surfactin were shown in gene transcript of GLU and CHI, respectively, and surfactin induced POX and LOX gene expression of citrus flavedo without pathogen infection. These results suggest that fengycin and surfactin act as elicitors of defense-related gene expression in "Valencia" fruit following infection. PMID:25329301