Sample records for citrus canker disease

  1. 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 ...

  2. REPEATABILITY AND COMPARISION OF IMAGE ANALYSIS AND VISUAL ASSESSMENT FOR DISEASE ASSESSMENT OF CITRUS CANKER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker, a disease of several citrus species, is caused by the bacterial pathogen Xanthomonas axonopodis pv citri (Xac). The disease is of concern in several wet tropical and subtropical citrus growing regions as infection results in yield loss and severely blemished fruit unsuitable for the f...

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

    Microsoft Academic Search

    Y. Hu; J. Zhang; H. Jia; D. Sosso; T. Li; W. B. Frommer; B. Yang; F. F. White; N. Wang; J. B. Jones

    2014-01-01

    Citrus bacterial canker (CBC) disease occurs worldwide and incurs considerable costs both from control measures and yield losses. Bacteria that cause CBC require one of six known type III transcription activator-like (TAL) effector genes for the characteristic pustule formation at the site of infection. Here, we show that Xanthomonas citri subspecies citri strain Xcc306, with the type III TAL effector

  4. 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...

  5. Transgenic sweet orange plants expressing a dermaseptin coding sequence show reduced symptoms of citrus canker disease.

    PubMed

    Furman, Nicolás; Kobayashi, Ken; Zanek, Maria Cecilia; Calcagno, Javier; Garcia, Maria Laura; Mentaberry, Alejandro

    2013-09-20

    Citrus canker provoked by Xanthomonas axonopodis pv. citri is a bacterial disease causing severe losses in all citrus-producing areas around the world. Xanthomonas infection is considered as an endemic disease in Northeast and Northwest Argentina, affecting as much as 10% of commercial citrus plantations. There is not known natural resistance neither in orange varieties nor in rootstocks used for grafting of commercial cultivars. To introduce resistance to this disease, plants of Pineapple sweet orange were transformed with a genetic construct allowing constitutive accumulation of dermaseptin. In comparison with non-transformed plants, transgenic plants showed symptom reduction levels of up to 50% in in planta assays performed under controlled conditions. PMID:23896218

  6. 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...

  7. Citrus Canker: Alternatives for Control

    NSDL National Science Digital Library

    Linda Weinland (Edison College; Biology)

    2006-05-20

    What do you do when county officials show up to cut down the orange trees in your backyard? What causes citrus canker and how is it spread? This plant pathogen was the first microbe to have its genome sequenced outside of the US. There is much to investigate before deciding on the best alternative for control. * examine international alternatives for the control of citrus canker

  8. 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...

  9. APS PRESS ONLINE LESSONS IN PLANT PATHOLOGY - CITRUS CANKER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker is a simple disease and a complex socioeconomic/political problem. The citrus canker eradication program over the past decade has been compromised by legal battles that halted eradication combined with exacerbation of the disease and tree susceptibility by the introduction of the Asia...

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

    PubMed Central

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

    2014-01-01

    Citrus bacterial canker (CBC) disease occurs worldwide and incurs considerable costs both from control measures and yield losses. Bacteria that cause CBC require one of six known type III transcription activator-like (TAL) effector genes for the characteristic pustule formation at the site of infection. Here, we show that Xanthomonas citri subspecies citri strain Xcc306, with the type III TAL effector gene pthA4 or with the distinct yet biologically equivalent gene pthAw from strain XccAw, induces two host genes, CsLOB1 and CsSWEET1, in a TAL effector-dependent manner. CsLOB1 is a member of the Lateral Organ Boundaries (LOB) gene family of transcription factors, and CsSWEET1 is a homolog of the SWEET sugar transporter and rice disease susceptibility gene. Both TAL effectors drive expression of CsLOB1 and CsSWEET1 promoter reporter gene fusions when coexpressed in citrus or Nicotiana benthamiana. Artificially designed TAL effectors directed to sequences in the CsLOB1 promoter region, but not the CsSWEET1 promoter, promoted pustule formation and higher bacterial leaf populations. Three additional distinct TAL effector genes, pthA*, pthB, and pthC, also direct pustule formation and expression of CsLOB1. Unlike pthA4 and pthAw, pthB and pthC do not promote the expression of CsSWEET1. CsLOB1 expression was associated with the expression of genes associated with cell expansion. The results indicate that CBC-inciting species of Xanthomonas exploit a single host disease susceptibility gene by altering the expression of an otherwise developmentally regulated gene using any one of a diverse set of TAL effector genes in the pathogen populations. PMID:24474801

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

    PubMed

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

    2014-01-28

    Citrus bacterial canker (CBC) disease occurs worldwide and incurs considerable costs both from control measures and yield losses. Bacteria that cause CBC require one of six known type III transcription activator-like (TAL) effector genes for the characteristic pustule formation at the site of infection. Here, we show that Xanthomonas citri subspecies citri strain Xcc306, with the type III TAL effector gene pthA4 or with the distinct yet biologically equivalent gene pthAw from strain XccA(w), induces two host genes, CsLOB1 and CsSWEET1, in a TAL effector-dependent manner. CsLOB1 is a member of the Lateral Organ Boundaries (LOB) gene family of transcription factors, and CsSWEET1 is a homolog of the SWEET sugar transporter and rice disease susceptibility gene. Both TAL effectors drive expression of CsLOB1 and CsSWEET1 promoter reporter gene fusions when coexpressed in citrus or Nicotiana benthamiana. Artificially designed TAL effectors directed to sequences in the CsLOB1 promoter region, but not the CsSWEET1 promoter, promoted pustule formation and higher bacterial leaf populations. Three additional distinct TAL effector genes, pthA*, pthB, and pthC, also direct pustule formation and expression of CsLOB1. Unlike pthA4 and pthAw, pthB and pthC do not promote the expression of CsSWEET1. CsLOB1 expression was associated with the expression of genes associated with cell expansion. The results indicate that CBC-inciting species of Xanthomonas exploit a single host disease susceptibility gene by altering the expression of an otherwise developmentally regulated gene using any one of a diverse set of TAL effector genes in the pathogen populations. PMID:24474801

  12. 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 ...

  13. 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 of the canker symptoms development during host susceptibility, or the defenses of sweet orange against the canker bacteria. We have narrowed down candidate targets to a few, which pointed out the host metabolic pathways explored by the pathogens. PMID:24564253

  14. 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...

  15. Citrus Canker: The Pathogen and Its Impact

    NSDL National Science Digital Library

    2002-01-01

    This Web site, currently featured on the home page of the American Phytopathological Society, contains a research report regarding the Asiatic citrus canker that has had devastating effects on Florida's citrus industry. The report, in a journal article format, thoroughly relates the natural history and current status of the disease, as well as detailing the methods and results of the (primarily genetic) experiments conducted in this study. One of the most appealing features of this Web site is the quality of the photos within the report. These photos can be viewed separately from the report in a slide show. While navigating this site is relatively straightforward, the lack of a table of contents can make finding your place in the body of the text somewhat confusing.

  16. POST-HURRICANE ANALYSIS OF CITRUS CANKER II: PREDICTIVE MODEL ESTIMATION OF DISEASE SPREAD AND AREA POTENTIALLY IMPACTED BY VARIOUS ERADICATION PROTOCOLS FOLLOWING CATASTROPHIC WEATHER EVENTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The affect of 2005 Hurricane Wilma on the dissemination of Xanthomonas axonopodis pv. citri (Xac), the cause of Asiatic citrus canker (ACC), and subsequent disease development was examined and predictions for the areas into which Xac was likely to have spread from known sources of infection was deve...

  17. 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...

  18. Automated image analysis of the severity of foliar citrus canker symptoms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (caused by Xanthomonas citri subsp. citri) is a destructive disease, reducing yield, and rendering fruit unfit for fresh sale. Accurate assessment of citrus canker severity and other diseases is needed for several purposes, including monitoring epidemics and evaluation of germplasm. ...

  19. Infection and decontamination of citrus-canker-inoculated leaf surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) is now considered endemic in Florida and continues to spread. Personnel and equipment decontamination is practiced in both disease-endemic and disease-free areas to reduce the risk of bacterial spread by man or machinery. We used grapefruit leaf su...

  20. CITRUS CANKER: DOING BATTLE WITH THE BEAST FOR NEARLY A CENTURY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asiatic citrus canker (ACC) has a long history in Florida. The disease was first found around 1910 and spread throughout the southeastern US on imported citrus seedlings from Japan. After an extensive eradication program, canker was declared eradicated from Florida and the adjacent states in 1933....

  1. Developing and implementing mating disruption for area-wide control of citrus leafminer and citrus canker disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Successful development and commercial launch of the first semiochemical-based control method for a major exotic insect pest and associated disease of citrus in Florida have resulted from vigorous collaboration between university and government researchers with support from private industry and innov...

  2. 78 FR 58992 - Notice of Request for Extension of Approval of an Information Collection; Citrus Canker...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-25

    ...Approval of an Information Collection; Citrus Canker; Interstate Movement of Regulated...quarantined areas to prevent the spread of citrus canker. DATES: We will consider all...regulated nursery stock and fruit from citrus canker quarantined areas, contact...

  3. Development and validation of standard area diagrams as assessment aids for estimating the severity of citrus canker on unripe oranges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Canker (caused by Xanthomonas citri subsp. citri) is an important disease of citrus in Brazil and elsewhere in the world, and can cause severe disease on the fruit. The severity of citrus canker of fruit must often be estimated visually. The objective of this research was to construct and validate s...

  4. 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...

  5. IMAGE ANALYSIS VERSUS VISUAL ASSESSMENT OF INCIDENCE AND SEVERITY OF CITRUS CANKER SYMPTOMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas axonopodis pv citri causes citrus canker. Disease assessment is important for monitoring epidemics. Visual assessment (VA) is presently the only reliable means of detection. To investigate how VA of symptoms compared to image analysis we used digital images of 214 citrus le...

  6. THE EFFECT OF HURRICANES AND TROPICAL STORMS ON LONG DISTANCE SPREAD OF CITRUS CANKER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asiatic citrus canker (ACC) is a serious disease of citrus that causes foliar and fruit lesions leading to extensive yield and quality losses. During Fall 2004, Florida experienced 3 hurricanes (Charlie, Francis, Jeanne) and one tropical storm (Ivan) whose paths crossed the majority of the commercia...

  7. LONG DISTANCE SPREAD OF CITRUS CANKER RELATED TO HURRICANES AND TROPICAL STORMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asiatic citrus canker (ACC) is a serious disease of citrus that causes foliar and fruit lesions leading to extensive yield and quality losses. During Fall 2004, Florida experienced 3 hurricanes (Charlie, Francis, Jeanne) and one tropical storm (Ivan) whose paths crossed the majority of the commercia...

  8. GENETIC DIVERSITY AND WORLDWIDE PROLIFERATION OF CITRUS BACTERIAL CANKER PATHOGENS IDENTIFIED IN HIRTORIC SPECIMENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus bacterial canker (CBC) caused by Xanthomonas axonopodis pv. citri (Xac) may have originated in Southeast Asia based on symptoms present on early herbarium specimens. The disease was first introduced into the United States in 1911 and has spread to most citrus producing areas in the world. Thi...

  9. GENETIC DIVERSITY AND WORLDWIDE PROLIFERATION OF CITRUS BACTERIAL CANKER PATHOGENS IDENTIFIED IN HISTORIC SPECIMENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus bacterial canker (CBC) caused by Xanthomonas axonopodis pv. citri (Xac) may have originated in Southeast Asia, based on symptoms present on early herbarium specimens. The disease was first introduced into the United States in 1911 and has spread to most citrus producing areas in the world. Th...

  10. 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...

  11. Characteristics of Multi-rater Estimates of Citrus Canker Severity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (CC, caused by Xanthomonas citri) was under eradication for 10 y in Florida. A total of 28 CC surveyors and plant pathologists rated severity of CC symptoms on 200 images to investigate the range of abilities and some factors that influence canker severity estimation. Actual dis...

  12. Managing citrus canker for the fresh fruit industry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The establishment of citrus canker in Florida changed the way the $400 million dollar industry grows, packs ships and stores fruit. Canker regulations have become less strict, but there is still a requirement for compliance for growers and packers to move fruit from Florida to other areas. The comp...

  13. PROGRESS TOWARDS THE DEVELOPMENT OF AN EFFECTIVE RISK ANALYSIS PROCESS FOR THE FLORIDA CITRUS NURSERY INDUSTRY TO MITIGATE THE IMPACT OF CITRUS CANKER AND HUANGLONGBING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The citrus industry within the state of Florida is being directly impacted by two recently introduced bacterial diseases, citrus canker and huanglongbing. As the commercial citrus industry is trying to develop efficient strategies to eradicate, control, or manage the diseases, it is becoming readil...

  14. Quantitative PCR Method for Diagnosis of Citrus Bacterial Canker

    PubMed Central

    Cubero, J.; Graham, J. H.; Gottwald, T. R.

    2001-01-01

    For diagnosis of citrus bacterial canker by PCR, an internal standard is employed to ensure the quality of the DNA extraction and that proper requisites exist for the amplification reaction. The ratio of PCR products from the internal standard and bacterial target is used to estimate the initial bacterial concentration in citrus tissues with lesions. PMID:11375206

  15. Copper Sprays and Windbreaks for Control of Citrus Canker on Young Orange Trees in Southern Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The benefit of windbreaks and copper sprays for control of citrus canker caused by Xanthomonas axonopodis pv. citri was investigated in a commercial citrus orchard located in a citrus canker endemic area in southern Brazil. Control of canker was evaluated as incidence and severity of lesions on foli...

  16. 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...

  17. Activity of citrus canker lesions on leaves, shoots and fruit of grapefruit in a Florida orchard from June 2010 to January 2011

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lesions of citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), on citrus fruit preclude export to certain markets. Characterizing the population dynamics of bacteria in canker lesions in commercial orchards can help gauge risk associated with diseased fruit entering fresh markets. The aim...

  18. 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...

  19. QCM immunoassay for recombinant cysteine peptidase: a potential protein biomarker for diagnosis of citrus canker.

    PubMed

    Afonso, André S; Zanetti, Bianca F; Santiago, Adelita C; Henrique-Silva, Flavio; Mattoso, Luiz H C; Faria, Ronaldo C

    2013-01-30

    Citrus canker is one of the most important agricultural citrus diseases worldwide. It is caused by Xanthomonas citri subsp. citri (Xcc) bacterium that infects leaves and the fruits produce a cysteine peptidase (CPXaC), which makes it a potential target for the development of effective and rapid detection methods for citrus canker. We report here the studies on the development of piezoelectric immunoassay for CPXaC using a polyclonal antibody against CPXaC (anti-CPXaC). Three different strategies for covalent immobilization of anti-CPXaC on gold surfaces were evaluated by monitoring the frequency (?f) and energy dissipation (?D) variation in real time when 64.5×10(-8) mol L(-1) CPXaC was added. Anti-CPXaC immobilized with 11-mercaptoundecanoic acid (MUA) showed the best relation between the frequency and dissipation factor variation, and strong values for the kinetic and equilibrium binding constant were obtained. The immunosensor showed a detection limit of 13.0 nmol L(-1) with excellent specificity, showing no response for different proteins that include another cysteine peptidase that is used as a target to detect Xylella fastidiosa bacterium, responsible for another important citrus disease. These results provide good perspectives for the use of CPXaC as a new biomarker for citrus canker. PMID:23597909

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

    PubMed

    Ahmad, Abdelmonim Ali; Askora, Ahmed; Kawasaki, Takeru; Fujie, Makoto; Yamada, Takashi

    2014-01-01

    In this study, filamentous phage XacF1, which can infect Xanthomonas axonopodis pv. citri (Xac) strains, was isolated and characterized. Electron microscopy showed that XacF1 is a member of the family Inoviridae and is about 600 nm long. The genome of XacF1 is 7325 nucleotides in size, containing 13 predicted open reading frames (ORFs), some of which showed significant homology to Ff-like phage proteins such as ORF1 (pII), ORF2 (pV), ORF6 (pIII), and ORF8 (pVI). XacF1 showed a relatively wide host range, infecting seven out of 11 strains tested in this study. Frequently, XacF1 was found to be integrated into the genome of Xac strains. This integration occurred at the host dif site (attB) and was mediated by the host XerC/D recombination system. The attP sequence was identical to that of Xanthomonas phage Cf1c. Interestingly, infection by XacF1 phage caused several physiological changes to the bacterial host cells, including lower levels of extracellular polysaccharide production, reduced motility, slower growth rate, and a dramatic reduction in virulence. In particular, the reduction in virulence suggested possible utilization of XacF1 as a biological control agent against citrus canker disease. PMID:25071734

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

    PubMed Central

    Ahmad, Abdelmonim Ali; Askora, Ahmed; Kawasaki, Takeru; Fujie, Makoto; Yamada, Takashi

    2014-01-01

    In this study, filamentous phage XacF1, which can infect Xanthomonas axonopodis pv. citri (Xac) strains, was isolated and characterized. Electron microscopy showed that XacF1 is a member of the family Inoviridae and is about 600 nm long. The genome of XacF1 is 7325 nucleotides in size, containing 13 predicted open reading frames (ORFs), some of which showed significant homology to Ff-like phage proteins such as ORF1 (pII), ORF2 (pV), ORF6 (pIII), and ORF8 (pVI). XacF1 showed a relatively wide host range, infecting seven out of 11 strains tested in this study. Frequently, XacF1 was found to be integrated into the genome of Xac strains. This integration occurred at the host dif site (attB) and was mediated by the host XerC/D recombination system. The attP sequence was identical to that of Xanthomonas phage Cf1c. Interestingly, infection by XacF1 phage caused several physiological changes to the bacterial host cells, including lower levels of extracellular polysaccharide production, reduced motility, slower growth rate, and a dramatic reduction in virulence. In particular, the reduction in virulence suggested possible utilization of XacF1 as a biological control agent against citrus canker disease. PMID:25071734

  2. Increased resistance against citrus canker mediated by a citrus mitogen-activated protein kinase.

    PubMed

    de Oliveira, Maria Luiza Peixoto; de Lima Silva, Caio Cesar; Abe, Valéria Yukari; Costa, Marcio Gilberto Cardoso; Cernadas, Raúl Andrés; Benedetti, Celso Eduardo

    2013-10-01

    Mitogen-activated protein kinases (MAPK) play crucial roles in plant immunity. We previously identified a citrus MAPK (CsMAPK1) as a differentially expressed protein in response to infection by Xanthomonas aurantifolii, a bacterium that causes citrus canker in Mexican lime but a hypersensitive reaction in sweet oranges. Here, we confirm that, in sweet orange, CsMAPK1 is rapidly and preferentially induced by X. aurantifolii relative to Xanthomonas citri. To investigate the role of CsMAPK1 in citrus canker resistance, we expressed CsMAPK1 in citrus plants under the control of the PR5 gene promoter, which is induced by Xanthomonas infection and wounding. Increased expression of CsMAPK1 correlated with a reduction in canker symptoms and a decrease in bacterial growth. Canker lesions in plants with higher CsMAPK1 levels were smaller and showed fewer signs of epidermal rupture. Transgenic plants also revealed higher transcript levels of defense-related genes and a significant accumulation of hydrogen peroxide in response to wounding or X. citri infection. Accordingly, nontransgenic sweet orange leaves accumulate both CsMAPK1 and hydrogen peroxide in response to X. aurantifolii but not X. citri infection. These data, thus, indicate that CsMAPK1 functions in the citrus canker defense response by inducing defense gene expression and reactive oxygen species accumulation during infection. PMID:23777433

  3. Development of a qPCR technique to screen for resistance to Asiatic citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asiatic citrus canker (Acc) (causal organism Xanthomonas citri subspc. citri (Xcc) is threatening sustainability of the Florida citrus industry. Resistant cultivars, whether developed through conventional breeding or genetic transformation, will be he best solution for dealint with Acc. In Florida...

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

    PubMed

    Li, Jinyun; Wang, Nian

    2014-02-01

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

  5. Exogenous treatment with salicylic acid attenuates occurrence of citrus canker in susceptible navel orange (Citrus sinensis Osbeck).

    PubMed

    Wang, Yin; Liu, Ji-Hong

    2012-08-15

    Citrus canker caused by Xanthomonas axonopodis pv. citri (Xac) is a devastating bacterial disease threatening the citrus industry. Salicylic acid (SA) plays a key role in plant defense response to biotic stress, but information is scarce concerning the application of SA to enhancing Xac resistance. In the present research attempts were made to investigate how exogenous application of SA influenced canker disease outbreak in navel orange (Citrus sinensis). Exogenously applied SA at 0.25 mM significantly enhanced the endogenous free and bound SA, particularly the latter. Upon exposure to Xac, lower disease incidence rate and smaller lesion sites were observed in the samples pre-treated with SA, accompanied by repression of bacterial growth at the lesion sites. Concurrent with the augmented disease resistance, SA-treated leaves had higher H?O? level and smaller stomata apertures before or after Xac infection when compared with their counterparts pre-treated with water (control). SA treatment elevated the activities of phenylalanine ammonia-lyase and ?-1,3-glucanase, but only the latter was higher in the SA-treated samples after Xac infection. In addition, mRNA levels of two pathogenesis-related genes, CsCHI and CsPR4A, were higher in the SA-treated samples relative to the control. Taken together, our results strongly suggest that the exogenously applied SA has evoked a cascade of physiological and molecular events that function singly or in concert to confer resistance to Xac invasion. PMID:22658220

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

    PubMed Central

    Fu, Xing-Zheng; Liu, Ji-Hong

    2013-01-01

    Citrus canker disease caused by Xanthomonas citri subsp. citri (Xcc) is one of the most devastating diseases affecting the citrus industry worldwide. In our previous study, the canker-resistant transgenic sweet orange (Citrus sinensis Osbeck) plants were produced via constitutively overexpressing a spermidine synthase. To unravel the molecular mechanisms underlying Xcc resistance of the transgenic plants, in the present study global transcriptional profiling was compared between untransformed line (WT) and the transgenic line (TG9) by hybridizing with Affymetrix Citrus GeneChip. In total, 666 differentially expressed genes (DEGs) were identified, 448 upregulated, and 218 downregulated. The DEGs were classified into 33 categories after Gene ontology (GO) annotation, in which 68 genes are in response to stimulus and involved in immune system process, 12 genes are related to cell wall, and 13 genes belong to transcription factors. These genes and those related to starch and sucrose metabolism, glutathione metabolism, biosynthesis of phenylpropanoids, and plant hormones were hypothesized to play major roles in the canker resistance of TG9. Semiquantitative RT-PCR analysis showed that the transcript levels of several candidate genes in TG9 were significantly higher than in WT both before and after Xcc inoculation, indicating their potential association with canker disease. PMID:23509803

  7. 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

    ...plant disease that is caused by a complex of Xanthomonas spp. bacteria and that affects plants and plant parts of citrus and citrus...the protocol document are adhered to, there should be no bacterium within the nursery or compartment. In that same section...

  8. 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

    2014-09-18

    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 (Xcc?fliC) 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

  9. Update on packing line protocols for citrus canker and their effects on bacterial survival

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Markets for Florida citrus are severely restricted by regulations in place to minimize the spread of citrus canker to citrus producing areas. Included in these regulations are accepted protocols for sanitation and coating of fruit. However, these measures do not eradicate all the living bacterial ce...

  10. 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

  11. The activity of citrus canker lseions on grapefruit in Florida, June 2009-January 2010

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lesions of citrus canker, caused by Xanthomonas citri subsp. citri (Xcc), on citrus fruit preclude sale of the fruit to the fresh market; the fruit must be juiced, which is less profitable. Assessing lesion activity in orchard-grown grapefruit provides information on the population dynamics of fruit...

  12. Modelling the progress of Asiatic citrus canker on Tahiti lime in relation to temperature and leaf wetness

    Microsoft Academic Search

    R. S. C. Christiano; M. Dalla Pria; W. C. Jesus Junior; L. Amorim; A. Bergamin Filho

    2009-01-01

    The combined effect of temperature (15°C, 20°C, 25°C, 30°C, 35°C, 40°C and 42°C) and leaf wetness duration (0, 4, 8 12, 16,\\u000a 20 and 24 h) on infection and development of Asiatic citrus canker (Xanthomonas citri subsp. citri) on Tahiti lime plant was examined in growth chambers. No disease developed at 42°C and zero hours of leaf wetness. Periods\\u000a of leaf

  13. DNA Polymorphisms and Biocontrol of Bacillus Antagonistic to Citrus Bacterial Canker with Indication of the Interference of Phyllosphere Biofilms

    PubMed Central

    Huang, Tzu-Pi; Tzeng, Dean Der-Syh; Wong, Amy C. L.; Chen, Chun-Han; Lu, Kuan-Min; Lee, Ya-Huei; Huang, Wen-Di; Hwang, Bing-Fang; Tzeng, Kuo-Ching

    2012-01-01

    Citrus bacterial canker caused by Xanthomonas axonopodis pv. citri is a devastating disease resulting in significant crop losses in various citrus cultivars worldwide. A biocontrol agent has not been recommended for this disease. To explore the potential of bacilli native to Taiwan to control this disease, Bacillus species with a broad spectrum of antagonistic activity against various phytopathogens were isolated from plant potting mixes, organic compost and the rhizosphere soil. Seven strains TKS1-1, OF3-16, SP4-17, HSP1, WG6-14, TLB7-7, and WP8-12 showing superior antagonistic activity were chosen for biopesticide development. The genetic identity based on 16S rDNA sequences indicated that all seven native strains were close relatives of the B. subtilis group and appeared to be discrete from the B. cereus group. DNA polymorphisms in strains WG6-14, SP4-17, TKS1-1, and WP8-12, as revealed by repetitive sequence-based PCR with the BOXA1R primers were similar to each other, but different from those of the respective Bacillus type strains. However, molecular typing of the strains using either tDNA-intergenic spacer regions or 16S–23S intergenic transcribed spacer regions was unable to differentiate the strains at the species level. Strains TKS1-1 and WG6-14 attenuated symptom development of citrus bacterial canker, which was found to be correlated with a reduction in colonization and biofilm formation by X. axonopodis pv. citri on leaf surfaces. The application of a Bacillus strain TKS1-1 endospore formulation to the leaf surfaces of citrus reduced the incidence of citrus bacterial canker and could prevent development of the disease. PMID:22848728

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emerging devastating diseases, such as Huanglongbing (HLB) and citrus canker, have caused tremendous losses to the citrus industry worldwide. Genetic engineering is a powerful approach that could allow us to increase citrus resistance against these diseases. The key to the success of this approach r...

  15. POST-HURRICANE ANALYSIS OF CITRUS CANKER SPREAD AND PROGRESS TOWARDS THE DEVELOPMENT OF A PREDICTIVE MODEL FOR FUTURE WEATHER RELATED SPREAD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker, caused by Xanthomonas axonopodis pv. citri (Xac), has been introduced into the state of Florida multiple times since the early 1900’s. With each discovery, an eradication program has been put into place to eliminate the disease. The most recent program began in 1996 and is still in ...

  16. Wind speed effects on the quantity of Xanthomonas citri subsp. citri dispersed downwind from canopies of grapefruit trees infected with citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The epidemic of citrus canker (Xanthomonas citri subsp. citri, Xcc) in Florida continues to expand since termination of the eradication program in 2006. Storms are known to be associated with disease spread, but little information exists on the interaction of fundamental physical and biological proc...

  17. POST-HURRICANE ANALYSIS OF CITRUS CANKER SPREAD AND PROGRESS TOWARDS THE DEVELOPMENT OF A PREDICTIVE MODEL FOR FUTURE WEATHER RELATED SPREAD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asiatic citrus canker (Xanthonomas axonopodis pv. citri) has had a long history in Florida and has been introduced multiple times since the early 1900’s. With each introduction or discovery, eradication programs have been implemented to attempt to eliminate the disease. The most recent eradication...

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

    PubMed

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

    2014-12-01

    A Gram-stain-positive, strictly aerobic, non-motile, coccoid bacterium, designated NCCP-154(T), was isolated from citrus leaf canker lesions and was subjected to a polyphasic taxonomic study. Strain NCCP-154(T) grew at 10-37 °C (optimum 30 °C) and at pH 7.0-8.0 (optimum pH 7.0). The novel strain exhibited tolerance of UV irradiation (>1000 J m(-2)). Based on 16S rRNA gene sequence analysis, strain NCCP-154(T) showed the highest similarity to Deinococcus gobiensis CGMCC 1.7299(T) (98.8?%), and less than 94?% similarity to other closely related taxa. The chemotaxonomic data [major menaquinone, MK-8; cell-wall peptidoglycan type, A3? (Orn-Gly2); major fatty acids, summed feature 3 (C16?:?1?7c/iso-C15?:?0 2-OH; 35.3?%) followed by C16?:?0 (12.7?%), iso-C17?:?1?9c (9.2?%), C17?:?1?8c (7.4?%) and iso-C17?:?0 (6.9?%); major polar lipids made up of several unidentified phosphoglycolipids and glycolipids and an aminophospholipid, and mannose as the predominant whole-cell sugar] also supported the affiliation of strain NCCP-154(T) to the genus Deinococcus. The level of DNA-DNA relatedness between strain NCCP-154(T) and D. gobiensis JCM 16679(T) was 63.3±3.7?%. The DNA G+C content of strain NCCP-154(T) was 70.0 mol%. Based on the phylogenetic analyses, DNA-DNA hybridization and physiological and biochemical characteristics, strain NCCP-154(T) can be differentiated from species with validly published names. Therefore, it represents a novel species of the genus Deinococcus. The name Deinococcus citri sp. nov. is proposed, with the type strain NCCP-154(T) (?=?JCM 19024(T)?=?DSM 24791(T)?=?KCTC 13793(T)). PMID:25256704

  19. ANNUAL AND POLYETIC PROGRESSION OF CITRUS CANKER ON TREES PROTECTED WITH COPPER SPRAYS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    : Mathematical models are important tools for comparative analysis of epidemics. In this paper, parameters obtained from the mathematical model that best fitted to the annual progress curves of citrus canker incidence were used to evaluate the effect of copper sprays and windbreaks on the annual and...

  20. PROSPECTS FOR CONTROL OF CITRUS CANKER WITH NOVEL CHEMICAL COMPOUNDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field trials conducted in Brazil demonstrate that copper formulations (copper hydroxide, CH; copper oxychloride, COC) even at reduced rates are consistently effective for control of canker on moderately susceptible orange varieties. Contact activity to replace and/or reduce copper could minimize po...

  1. Geo-referenced spatiotemporal analysis of the urban citrus canker epidemic in Florida.

    PubMed

    Gottwald, Tim R; Sun, Xiaoan; Riley, Tim; Graham, James H; Ferrandino, Frank; Taylor, Earl L

    2002-04-01

    ABSTRACT Five areas in urban Miami were identified to study the spread of Xanthomonas axonopodis pv. citri to determine if the practice of removing exposed citrus trees within 38.1 m of trees affected by citrus canker was adequate to curtail further bacterial spread. To accomplish this, 18,769 trees in dooryards were surveyed, geo-referenced by differential global positioning systems (GPS), and assayed for disease severity, age of infection, citrus cultivar, location of infection in tree, and canopy size. For each tree, the date the tree became infected was estimated and used to separate trees into contiguous 30-day categories. For each area studied, distance measurements between focal trees and newly infected trees were calculated for various temporal periods of 30, 60, 90, and 120 days in duration, corresponding to intervals of inspection survey. A visual basic application was used to calculate the distances between each newly diseased tree and all prior focal trees. The nearest distance was used because it was considered the most conservative estimate possible. It is therefore likely to be an underestimate of spread but is a good estimate of the minimum possible distances of spread. For the first four 30-day periods among the five study areas, calculated maximum distances of spread ranged from 12 to 3,474 m, indicating a broad continuum of distance for bacterial spread was possible. Disease increased during the first two-thirds of the time studied and reached an asymptote due to dry conditions in the final one-third of the duration of the study. Cross correlation analysis indicated that disease was best visualized 107 days following rainstorms with wind. Analysis of regional spatial point patterns was performed temporally for each 30-day period via a modified Ripley's K-function. Spatiotemporal analyses between periods over areas larger than previously examined were accomplished via spatiotemporal semivariogram analysis. These methods in combination demonstrated rapid increases in range of spatial dependency and range of spatiotemporal dependency for all study sites. This corresponded to rapid spread of disease across the regions studied in response to rainstorms with wind followed by a "filling in" of disease on remaining noninfected susceptible trees through time by less intense rain events. A stochastic quadratization technique demonstrated that disease incidence and disease severity were not greatly affected by urban host density but were positively correlated to host susceptibility within local 0.25-km(2) quadrats. PMID:18942949

  2. 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...

  3. Modifications of Xanthomonas axonopodis pv. citri Lipopolysaccharide Affect the Basal Response and the Virulence Process during Citrus Canker

    PubMed Central

    Petrocelli, Silvana; Tondo, María Laura; Daurelio, Lucas D.; Orellano, Elena G.

    2012-01-01

    Xanthomonas axonopodis pv. citri (Xac) is the phytopathogen responsible for citrus canker, one of the most devastating citrus diseases in the world. A broad range of pathogens is recognized by plants through so-called pathogen-associated molecular patterns (PAMPs), which are highly conserved fragments of pathogenic molecules. In plant pathogenic bacteria, lipopolisaccharyde (LPS) is considered a virulence factor and it is being recognized as a PAMP. The study of the participation of Xac LPS in citrus canker establishment could help to understand the molecular bases of this disease. In the present work we investigated the role of Xac LPS in bacterial virulence and in basal defense during the interaction with host and non host plants. We analyzed physiological features of Xac mutants in LPS biosynthesis genes (wzt and rfb303) and the effect of these mutations on the interaction with orange and tobacco plants. Xac mutants showed an increased sensitivity to external stresses and differences in bacterial motilities, in vivo and in vitro adhesion and biofilm formation. Changes in the expression levels of the LPS biosynthesis genes were observed in a medium that mimics the plant environment. Xacwzt exhibited reduced virulence in host plants compared to Xac wild-type and Xacrfb303. However, both mutant strains produced a lower increase in the expression levels of host plant defense-related genes respect to the parental strain. In addition, Xac LPS mutants were not able to generate HR during the incompatible interaction with tobacco plants. Our findings indicate that the structural modifications of Xac LPS impinge on other physiological attributes and lead to a reduction in bacterial virulence. On the other hand, Xac LPS has a role in the activation of basal defense in host and non host plants. PMID:22792211

  4. The epidemiological significance of post-packinghouse survival of Xanthomonas citri ssp. citri for dissemination of Asiatic citrus canker via infected fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The risk of introduction of Xanthomonas citri spp. citri (Xcc) to new, unaffected citrus producing areas is a major concern for those citrus industries attempting to remain free of citrus canker. Citrus fruit, as a potential pathway for Xcc to enter and become established in these areas, is assumed...

  5. Bayesian Analysis for Inference of an Emerging Epidemic: Citrus Canker in Urban Landscapes

    PubMed Central

    Neri, Franco M.; Cook, Alex R.; Gibson, Gavin J.; Gottwald, Tim R.; Gilligan, Christopher A.

    2014-01-01

    Outbreaks of infectious diseases require a rapid response from policy makers. The choice of an adequate level of response relies upon available knowledge of the spatial and temporal parameters governing pathogen spread, affecting, amongst others, the predicted severity of the epidemic. Yet, when a new pathogen is introduced into an alien environment, such information is often lacking or of no use, and epidemiological parameters must be estimated from the first observations of the epidemic. This poses a challenge to epidemiologists: how quickly can the parameters of an emerging disease be estimated? How soon can the future progress of the epidemic be reliably predicted? We investigate these issues using a unique, spatially and temporally resolved dataset for the invasion of a plant disease, Asiatic citrus canker in urban Miami. We use epidemiological models, Bayesian Markov-chain Monte Carlo, and advanced spatial statistical methods to analyse rates and extent of spread of the disease. A rich and complex epidemic behaviour is revealed. The spatial scale of spread is approximately constant over time and can be estimated rapidly with great precision (although the evidence for long-range transmission is inconclusive). In contrast, the rate of infection is characterised by strong monthly fluctuations that we associate with extreme weather events. Uninformed predictions from the early stages of the epidemic, assuming complete ignorance of the future environmental drivers, fail because of the unpredictable variability of the infection rate. Conversely, predictions improve dramatically if we assume prior knowledge of either the main environmental trend, or the main environmental events. A contrast emerges between the high detail attained by modelling in the spatiotemporal description of the epidemic and the bottleneck imposed on epidemic prediction by the limits of meteorological predictability. We argue that identifying such bottlenecks will be a fundamental step in future modelling of weather-driven epidemics. PMID:24762851

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

    PubMed

    Neri, Franco M; Cook, Alex R; Gibson, Gavin J; Gottwald, Tim R; Gilligan, Christopher A

    2014-04-01

    Outbreaks of infectious diseases require a rapid response from policy makers. The choice of an adequate level of response relies upon available knowledge of the spatial and temporal parameters governing pathogen spread, affecting, amongst others, the predicted severity of the epidemic. Yet, when a new pathogen is introduced into an alien environment, such information is often lacking or of no use, and epidemiological parameters must be estimated from the first observations of the epidemic. This poses a challenge to epidemiologists: how quickly can the parameters of an emerging disease be estimated? How soon can the future progress of the epidemic be reliably predicted? We investigate these issues using a unique, spatially and temporally resolved dataset for the invasion of a plant disease, Asiatic citrus canker in urban Miami. We use epidemiological models, Bayesian Markov-chain Monte Carlo, and advanced spatial statistical methods to analyse rates and extent of spread of the disease. A rich and complex epidemic behaviour is revealed. The spatial scale of spread is approximately constant over time and can be estimated rapidly with great precision (although the evidence for long-range transmission is inconclusive). In contrast, the rate of infection is characterised by strong monthly fluctuations that we associate with extreme weather events. Uninformed predictions from the early stages of the epidemic, assuming complete ignorance of the future environmental drivers, fail because of the unpredictable variability of the infection rate. Conversely, predictions improve dramatically if we assume prior knowledge of either the main environmental trend, or the main environmental events. A contrast emerges between the high detail attained by modelling in the spatiotemporal description of the epidemic and the bottleneck imposed on epidemic prediction by the limits of meteorological predictability. We argue that identifying such bottlenecks will be a fundamental step in future modelling of weather-driven epidemics. PMID:24762851

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

    PubMed

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

    2015-03-01

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

  8. Under severe HLB and citrus canker pressure, 'Triumph' and 'Jackson' perform better than 'Flame' and 'Marsh' grapefruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) and Citrus Canker (CC) threaten the viability of Florida grapefruit production. ‘Triumph’ (T), reportedly a grapefruit/sweet orange hybrid, is similar to seedy white grapefruit with earlier maturity and lower bitterness. ‘Jackson’ (J) is a low-seeded budsport of ‘Triumph’. Tree h...

  9. Under severe citrus canker and HLB (Huanglongbing) pressure, Triumph and Jackson perform better than Flame and Marsh grapefruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) and Citrus Canker (CC) threaten the viability of Florida grapefruit production. Triumph (T), reportedly a grapefruit/sweet orange hybrid, is similar to seedy white grapefruit with earlier maturity and lower bitterness. Jackson (J) is a low-seeded budsport of Triumph. Tree health ...

  10. Surface barriers of mandarin 'okitsu' leaves make a major contribution to canker disease resistance.

    PubMed

    Favaro, María A; Micheloud, Norma G; Roeschlin, Roxana A; Chiesa, María A; Castagnaro, Atilio P; Vojnov, Adrián A; Gmitter, Fred G; Gadea, José; Rista, Luis M; Gariglio, Norberto F; Marano, María R

    2014-09-01

    Field evaluations have shown that Satsuma mandarin (Citrus unshiu) 'Okitsu' is one of the mandarin cultivars that shows substantial resistance to Xanthomonas citri subsp. citri (X. citri), the causal agent of citrus bacterial canker disease. However, the mechanisms underlying this resistance are not well understood. In this study, we have shown that 'Okitsu' leaves are nevertheless susceptible to X. citri infection during a period of their development; however, this period is shorter than that seen in the susceptible mandarin 'Clemenules' (C. clementina). Under controlled growth conditions, the resistance of 'Okitsu' to X. citri was associated with the age of the leaf and was evident in spray-inoculated plants but not in those inoculated by infiltration. Furthermore, X. citri showed reduced attachment and biofilm formation in 'Okitsu' leaves compared with 'Clemenules'. Taken together, our data suggest that structural features of the 'Okitsu' leaf surface, such as the physical properties of the cuticle, are involved in the resistance to X. citri. PMID:24548213

  11. The LOV Protein of Xanthomonas citri subsp. citri Plays a Significant Role in the Counteraction of Plant Immune Responses during Citrus Canker

    PubMed Central

    Kraiselburd, Ivana; Daurelio, Lucas D.; Tondo, María Laura; Merelo, Paz; Cortadi, Adriana A.; Talón, Manuel; Tadeo, Francisco R.; Orellano, Elena G.

    2013-01-01

    Pathogens interaction with a host plant starts a set of immune responses that result in complex changes in gene expression and plant physiology. Light is an important modulator of plant defense response and recent studies have evidenced the novel influence of this environmental stimulus in the virulence of several bacterial pathogens. Xanthomonas citri subsp. citri is the bacterium responsible for citrus canker disease, which affects most citrus cultivars. The ability of this bacterium to colonize host plants is influenced by bacterial blue-light sensing through a LOV-domain protein and disease symptoms are considerably altered upon deletion of this protein. In this work we aimed to unravel the role of this photoreceptor during the bacterial counteraction of plant immune responses leading to citrus canker development. We performed a transcriptomic analysis in Citrus sinensis leaves inoculated with the wild type X. citri subsp. citri and with a mutant strain lacking the LOV protein by a cDNA microarray and evaluated the differentially regulated genes corresponding to specific biological processes. A down-regulation of photosynthesis-related genes (together with a corresponding decrease in photosynthesis rates) was observed upon bacterial infection, this effect being more pronounced in plants infected with the lov-mutant bacterial strain. Infection with this strain was also accompanied with the up-regulation of several secondary metabolism- and defense response-related genes. Moreover, we found that relevant plant physiological alterations triggered by pathogen attack such as cell wall fortification and tissue disruption were amplified during the lov-mutant strain infection. These results suggest the participation of the LOV-domain protein from X. citri subsp. citri in the bacterial counteraction of host plant defense response, contributing in this way to disease development. PMID:24260514

  12. Detecting Citrus Canker using Hyperspectral Reflectance Imaging and PCA-based Image Classification Method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A portable hyperspectral imaging system was developed to measure the reflectance images from citrus samples with normal and various common diseased skin conditions in the wavelength range between 400 nm and 900 nm. PCA was used to reduce the spectral dimension of the 3-D hyperspectral image data and...

  13. Population Structure of Geosmithia morbida, the Causal Agent of Thousand Cankers Disease of Walnut Trees in

    E-print Network

    Population Structure of Geosmithia morbida, the Causal Agent of Thousand Cankers Disease of Walnut. Graves3 , Colleen Hartel4 , Jay W. Pscheidt5 , Jadelys Tonos4 , Kirk Broders6 , Whitney Cranshaw1 morbida and the walnut twig beetle Pityophthorus juglandis are associated with thousand cankers disease

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

    PubMed Central

    Lu, Hua; Zhang, Chong; Albrecht, Ute; Shimizu, Rena; Wang, Guanfeng; Bowman, Kim D.

    2013-01-01

    Emerging devastating diseases, such as Huanglongbing (HLB) and citrus canker, have caused tremendous losses to the citrus industry worldwide. Genetic engineering is a powerful approach that could allow us to increase citrus resistance against these diseases. The key to the success of this approach relies on a thorough understanding of defense mechanisms of citrus. Studies of Arabidopsis and other plants have provided a framework for us to better understand defense mechanisms of citrus. Salicylic acid (SA) is a key signaling molecule involved in basal defense and resistance (R) gene-mediated defense against broad-spectrum pathogens. The Arabidopsis gene NDR1 (NON-RACE-SPECIFIC DISEASE RESISTANCE 1) is a positive regulator of SA accumulation and is specifically required for signaling mediated by a subset of R genes upon recognition of their cognate pathogen effectors. Our bioinformatic analysis identified an ortholog of NDR1 from citrus, CsNDR1. Overexpression of CsNDR1 complemented susceptibility conferred by the Arabidopsis ndr1-1 mutant to Pseudomonas syringae strains and also led to enhanced resistance to an oomycete pathogen Hyaloperonospora arabidopsidis. Such heightened resistance is associated with increased SA production and expression of the defense marker gene PATHOGENESIS RELATED 1 (PR1). In addition, we found that expression of PR1 and accumulation of SA were induced to modest levels in citrus infected with Candidatus Liberibacter asiaticus, the bacterial pathogen associated with HLB disease. Thus, our data suggest that CsNDR1 is a functional ortholog of Arabidopsis NDR1. Since Ca. L. asiaticus infection only activates modest levels of defense responses in citrus, we propose that genetically increasing SA/NDR1-mediated pathways could potentially lead to enhanced resistance against HLB, citrus canker, and other destructive diseases challenging global citrus production. PMID:23761797

  15. A novel Fusarium species causes a canker disease of the critically endangered conifer, Torreya taxifolia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A canker disease of Florida torreya (Torreya taxifolia), here designated CDFT, has been implicated in the decline of this critically endangered species in its native range of northern Florida and southeastern Georgia. In our current surveys of eight Florida torreya sites, cankers were present on all...

  16. SPATIAL PATTERN ANALYSIS OF CITRUS CANKER INFECTED PLANTINGS IN SÃO PAULO BRAZIL AND IMPLICATION OF THE ASIAN LEAFMINER ON THE POTENTIAL DISPERSAL PROCESSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eradication of Asiatic Citrus Canker (ACC) has become increasingly difficult over the last decade following the introduction of the Asian leafminer into Brazil and Florida, which lead to changes in the eradication protocols. The present study, undertaken in Brazil, was aimed at characterizing the s...

  17. ESTIMATING THE INCREASE AND SPREAD OF CITRUS CANKER CAUSED BY THE INTERACTION OF PEDESTRIAN VERSUS CATASTROPHIC WEATHER EVENTS, HUMANS, AND BAD LUCK

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The bacteria, Xanthomonas axonopodis pv. citri (Xac), that causes Asiatic Citrus Canker (ACC) can move in any of a variety of modes in the presence of free moisture. From a meteorological point of view, gentle rain, rain with wind, rain storms, tropical storms, and hurricanes can all disperse Xac i...

  18. SPATIAL PATTERN ANALYSIS OF CITRUS CANKER INFECTED PLANTINGS IN SAO PAULO BRAZIL AND IMPLICATION OF THE ASIAN LEAFMINER ON POTENTIAL DISPERSAL PROCESSES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eradication of Asiatic Citrus Canker (ACC) has become increasingly difficult over the last decade following the introduction of the Asian leafminer into Brazil and Florida. This prompted epidemiological studies in both countries that resulted in changes in the eradication protocols. The objective ...

  19. Distribution of canker lesions on grapefruit in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker, caused by the plant pathogenic bacterium Xanthomonas citri subsp. citri (Xcc) is an important disease of grapefruit in Florida. To establish disease distribution on fruit, six samples of 24 diseased grapefruit were collected from two groves in east Florida. A plane was sliced through ...

  20. Oak tree canker disease supports arthropod diversity in a natural ecosystem.

    PubMed

    Lee, Yong-Bok; An, Su Jung; Park, Chung Gyoo; Kim, Jinwoo; Han, Sangjo; Kwak, Youn-Sig

    2014-03-01

    Microorganisms have many roles in nature. They may act as decomposers that obtain nutrients from dead materials, while some are pathogens that cause diseases in animals, insects, and plants. Some are symbionts that enhance plant growth, such as arbuscular mycorrhizae and nitrogen fixation bacteria. However, roles of plant pathogens and diseases in natural ecosystems are still poorly understood. Thus, the current study addressed this deficiency by investigating possible roles of plant diseases in natural ecosystems, particularly, their positive effects on arthropod diversity. In this study, the model system was the oak tree (Quercus spp.) and the canker disease caused by Annulohypoxylon truncatum, and its effects on arthropod diversity. The oak tree site contained 44 oak trees; 31 had canker disease symptoms while 13 were disease-free. A total of 370 individual arthropods were detected at the site during the survey period. The arthropods belonged to 25 species, 17 families, and seven orders. Interestingly, the cankered trees had significantly higher biodiversity and richness compared with the canker-free trees. This study clearly demonstrated that arthropod diversity was supported by the oak tree canker disease. PMID:25288984

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

    PubMed Central

    Lee, Yong-Bok; An, Su Jung; Park, Chung Gyoo; Kim, Jinwoo; Han, Sangjo; Kwak, Youn-Sig

    2014-01-01

    Microorganisms have many roles in nature. They may act as decomposers that obtain nutrients from dead materials, while some are pathogens that cause diseases in animals, insects, and plants. Some are symbionts that enhance plant growth, such as arbuscular mycorrhizae and nitrogen fixation bacteria. However, roles of plant pathogens and diseases in natural ecosystems are still poorly understood. Thus, the current study addressed this deficiency by investigating possible roles of plant diseases in natural ecosystems, particularly, their positive effects on arthropod diversity. In this study, the model system was the oak tree (Quercus spp.) and the canker disease caused by Annulohypoxylon truncatum, and its effects on arthropod diversity. The oak tree site contained 44 oak trees; 31 had canker disease symptoms while 13 were disease-free. A total of 370 individual arthropods were detected at the site during the survey period. The arthropods belonged to 25 species, 17 families, and seven orders. Interestingly, the cankered trees had significantly higher biodiversity and richness compared with the canker-free trees. This study clearly demonstrated that arthropod diversity was supported by the oak tree canker disease. PMID:25288984

  2. A New Canker Disease of Apple, Pear, and Plum Rootstocks Caused by Diaporthe ambigua in South Africa

    E-print Network

    A New Canker Disease of Apple, Pear, and Plum Rootstocks Caused by Diaporthe ambigua in South., Wingfield. B. D.. Wingfield. M. 1., and Calitz. F. J. 1996. A new canker disease of apple. pear, and plum was found to be the c:J.useof a newly recognized disease of apple. pear, and plum rootstocks in South Africa

  3. TPCP: Pitch canker PITCH CANKER

    E-print Network

    TPCP: Pitch canker PITCH CANKER INTRODUCTION Pitch canker is one of the most serious threats crown. Large amounts of pitch accumulate on and below the cankers. The wood beneath the cankers is deeply pitch soaked, often to the pith. This characteristic distinguishes pitch canker, from cankers

  4. Effect of copper hydroxide sprays for citrus canker control on wild type Escherichia coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies were performed in vitro with bacteria grown in broth and then subjected to the same copper hydroxide concentrations as are sprayed on citrus trees in Florida throughout the growing season. Studies were also undertaken with grapefruit leaves and the survival of Escherichia coli (E. coli) on t...

  5. AMPLIFICATION OF DNA OF XANTHOMONAS AXONOPODIS PV CITRI FROM HISTORIC CITRUS CANKER HERBARIUM SPECIMENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 c...

  6. 75 FR 34419 - Notice of Revision and Request for Extension of Approval of an Information Collection; Citrus...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-17

    ...Approval of an Information Collection; Citrus Canker; Interstate Movement of Regulated...quarantined areas to prevent the spread of citrus canker and to request an extension of...quarantined areas to prevent the spread of citrus canker, contact Ms. Lynn...

  7. Economic Impacts of the Florida Citrus Industry in Alan Hodges, Mohammad Rahmani, and David Mulkey2

    E-print Network

    Florida, University of

    FE633 Economic Impacts of the Florida Citrus Industry in 2003-041 Alan Hodges, Mohammad Rahmani Introduction The citrus industry remains a major part of Florida's agricultural and natural resource economy. However, recently it has been adversely affected by hurricanes and diseases such as citrus canker

  8. Transcriptome Profiling of Citrus Fruit Response to Huanglongbing Disease

    E-print Network

    D'Souza, Raissa

    Transcriptome Profiling of Citrus Fruit Response to Huanglongbing Disease Federico Martinelli1) or ``citrus greening'' is the most destructive citrus disease worldwide. In this work, we studied host responses of citrus to infection with Candidatus Liberibacter asiaticus (CaLas) using next

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

    PubMed Central

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

    2012-01-01

    Citrus canker disease caused by Xanthomonas citri subsp. citri (Xcc) is one of the most devastating biotic stresses affecting the citrus industry. Meiwa kumquat (Fortunella crassifolia) is canker-resistant, while Newhall navel orange (Citrus sinensis Osbeck) is canker-sensitive. To understand the molecular mechanisms underlying the differences in responses to Xcc, transcriptomic profiles of these two genotypes following Xcc attack were compared by using the Affymetrix citrus genome GeneChip. A total of 794 and 1324 differentially expressed genes (DEGs) were identified as canker-responsive genes in Meiwa and Newhall, respectively. Of these, 230 genes were expressed in common between both genotypes, while 564 and 1094 genes were only significantly expressed in either Meiwa or Newhall. Gene ontology (GO) annotation and Singular Enrichment Analysis (SEA) of the DEGs showed that genes related to the cell wall and polysaccharide metabolism were induced for basic defense in both Meiwa and Newhall, such as chitinase, glucanase and thaumatin-like protein. Moreover, apart from inducing basic defense, Meiwa showed specially upregulated expression of several genes involved in the response to biotic stimulus, defense response, and cation binding as comparing with Newhall. And in Newhall, abundant photosynthesis-related genes were significantly down-regulated, which may be in order to ensure the basic defense. This study revealed different molecular responses to canker disease in Meiwa and Newhall, affording insight into the response to canker and providing valuable information for the identification of potential genes for engineering canker tolerance in the future. PMID:22848606

  10. THE EFFECT OF WIND SPEED ON THE DISPERSAL PLUME OF BACTERIA DOWNWIND FROM CANKER-INFECTED GRAPEFRUIT TREES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas axonopodis pv citri causes citrus canker. Disease assessment is important for monitoring epidemics. Visual assessment (VA) is presently the only reliable means of detection. To investigate how VA of symptoms compared to image analysis we used digital images of 214 citrus le...

  11. Multiple leafminer species attracted to the major pheromone components of the citrus leafminer Phyllocnistis citrella (Lepidoptera: Gracillariidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The citrus leafminer, Phyllocnistis citrella Stainton, is a major pest of citrus throughout the world due to leafmining damage that reduces photosynthetic capacity of leaves and increases the incidence and severity of citrus canker disease. A lure comprised of two aldehyde compounds isolated from ph...

  12. 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...

  13. 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...

  14. THE CHANGE IN QUANTITY OF BACTERIA OF XANTHOMONAS AXONOPODIS PV CITRI DISPERSED DOWN WIND FROM CANKER-INFECTED GRAPEFRUIT TREES DURING A WIND/RAIN EVENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The yield and marketability of citrus is limited in several tropical wet parts of the world by citrus canker (caused by Xanthomonas axonopodis pv. citri, Xac). The disease can cause severe epidemics and there are few options for control, although eradication has been favored (1). A thorough knowledg...

  15. 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...

  16. 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...

  17. The HPLC-Fluorescence Detection of Coumarins in ‘Hamlin’ Sweet Orange and ‘Marsh’ Grapefruit Leaf Cankers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Canker is a devastating disease for the citrus fresh fruit market and is caused by the pathogenic bacterium Xanthomonas citri var. citri (Xcc). Infection occurs by bacterial penetration through physical damage of leaves, peel and stems, and also by bacterial entry through the stomates of these photo...

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

    Microsoft Academic Search

    Michael G Bausher; Nameirakpam D Singh; Seung-Bum Lee; Robert K Jansen; Henry Daniell

    2006-01-01

    BACKGROUND: The production of Citrus, the largest fruit crop of international economic value, has recently been imperiled due to the introduction of the bacterial disease Citrus canker. No significant improvements have been made to combat this disease by plant breeding and nuclear transgenic approaches. Chloroplast genetic engineering has a number of advantages over nuclear transformation; it not only increases transgene

  19. Canker sore

    MedlinePLUS

    ... and minerals in the diet (especially iron, folic acid , or vitamin B-12 ) Hormonal changes Food allergies Anyone can develop a canker sore. Women are more likely to get them than men. Canker sores may run in families.

  20. Area-wide mating disruption of a major citrus pest using an off-ratio blend

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The leafminer Phyllocnistis citrella (Lepidoptera: Gracillariidae) is a global pest of citrus and contributes to the incidence and severity of citrus bacterial canker disease. Results of response surface models generated by mixture-amount experiments suggested that an off-ratio blend consisting of t...

  1. Bacteria causing important diseases of citrus utilise distinct modes of pathogenesis to attack a common host.

    PubMed

    Vojnov, Adrián Alberto; do Amaral, Alexandre Morais; Dow, John Maxwell; Castagnaro, Atilio Pedro; Marano, Marìa Rosa

    2010-06-01

    In this review, we summarise the current knowledge on three pathogens that exhibit distinct tissue specificity and modes of pathogenesis in citrus plants. Xanthomonas axonopodis pv. citri causes canker disease and invades the host leaf mesophyll tissue through natural openings and can also survive as an epiphyte. Xylella fastidiosa and Candidatus Liberibacter are vectored by insects and proliferate in the vascular system of the host, either in the phloem (Candidatus Liberibacter) or xylem (X. fastidiosa) causing variegated chlorosis and huanglongbing diseases, respectively. Candidatus Liberibacter can be found within host cells and is thus unique as an intracellular phytopathogenic bacterium. Genome sequence comparisons have identified groups of species-specific genes that may be associated with the particular lifestyle, mode of transmission or symptoms produced by each phytopathogen. In addition, components that are conserved amongst bacteria may have diverse regulatory actions underpinning the different bacterial lifestyles; one example is the divergent role of the Rpf/DSF cell-cell signalling system in X. citri and X. fastidiosa. Biofilm plays a key role in epiphytic fitness and canker development in X. citri and in the symptoms produced by X. fastidiosa. Bacterial aggregation may be associated with vascular occlusion of the xylem vessels and symptomatology of variegated chlorosis. PMID:20449739

  2. 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 ...

  3. Citrus viroid II variants associated with ‘Gummy Bark’ disease

    Microsoft Academic Search

    N. önelge; A. Cinar; J. A. Szychowski; G. Vidalakis; J. S. Semancik

    2004-01-01

    A viroid etiology for citrus gummy bark (CGB) disease of sweet orange is supported by the similarity of symptom expression to cachexia disease of mandarins and tangelos caused by the hop stunt viroid (HSVd) related citrus viroid II (CVd-II), as well as the detection of CVd-II variants in CGB infected Washington navel and Dörtyol sweet orange, a Turkish cultivar. A

  4. Identification of microsatellites from Geosmithia morbida, the fungus associated with Thousand Canker Disease (TCD) of Walnut, and their use

    E-print Network

    Identification of microsatellites from Geosmithia morbida, the fungus associated with Thousand Canker Disease (TCD) affects trees of the genus Juglans. It is caused by a beetle/fungus symbiotic to spread throughout the range of J. nigra. The fungus associated with TCD is Geosmithia morbida, a newly

  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. SCREENING CITRUS GERMPLASM FOR RESISTANCE TO XANTHORMONOS AXONOPODIS PV.CTRI

    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...

  7. PHENYLACETALDEHYDE O-METHYLOXIME: A VOLATILE COMPOUND FROM PLANTS INFECTED WITH CITRUS CANKER PATHOGENIC BACTERIUM, XANTHOMONAS AXONOPODIS PV. CITRI.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An aldehyde oxime o-methyl ether, phenylacetaldehyde o-methyloxime (PAAMO), was detected using solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) in the headspace above grapefruit leaves infected with Xanthomonas axonopodis pv. citri, the causal agent of citrus bacte...

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

    PubMed

    Lopez-Zamora, Isabel; Bliss, Christine; Jokela, Eric J; Comerford, N B; Grunwald, Sabine; Barnard, E; Vasquez, G M

    2007-05-01

    Pitch canker disease (Fusarium circinatum Nirenberg & O'Donnell) causes serious shoot dieback, reduced growth and mortality in pines found in the southern and western USA, and has been linked to nutrient imbalances. Poultry houses with forced-air ventilation systems produce nitrogen (N) emissions. This study analyzed spatial correlations between pitch canker disease and foliar, forest floor, soil, and throughfall N in a slash pine (Pinus elliottii var. elliottii Engelm.) plantation adjacent to a poultry operation in north Florida, USA. Tissue and throughfall N concentrations were highest near the poultry houses and remained elevated for 400 m. Disease incidence ranged from 57-71% near the poultry houses and was spatially correlated with N levels. Similarly, stem mortality ranged from 41-53% in the most heavily impacted area, and declined to 0-9% at distances greater than 400 m. These results suggest that nutritional processes exacerbate changes in disease susceptibility and expression in slash pine. PMID:17049465

  9. Research progress for integrated canker management

    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 2013, crop losses in Hamlin f...

  10. Factors affecting infection of citrus with Xanthomonas axonopodis pv citri.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas axonopodis pv citri (Xac) causes citrus canker and is now considered endemic in Florida. Factors affecting dispersal and infection of the bacteria need to be understood to help optimize disease management strategies. Wind (0-18 m/sec) was simulated outdoors using a fan to study infection...

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

    DOEpatents

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

    2011-03-22

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

  12. Estimation of Citrus Stubborn Disease Incidence in Citrus Groves by real-time PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A rapid and sensitive method is needed to detect Spiroplasma citri, the causal agent of citrus stubborn disease (CSD), for epidemiology studies and implementation of CSD management strategies. Real-time polymerase chain reaction (PCR) was developed for detection of S. citri using the DNA binding fl...

  13. Progeny differences of hinoki ( Chamaecyparis obtusa ) and sawara ( C. pisifera ) against resinous stem canker disease and spatial distribution of damage (disease severity) in a progeny test

    Microsoft Academic Search

    Makoto Takahashi; Minoru Mukouda; Kenji Nishimura

    1998-01-01

    The incidence and severity of resinous stem canker disease were investigated in hinoki (Chamaecyparis obtusa) and sawara (C. pisifera) at a progeny test located in Yamatsuri Town, Fukushima Prefecture, Japan. Symptoms of the disease were observed in 307 trees\\u000a out of 933 investigated trees (32.9%). The damage was more severe on lower slopes than on upper slopes, indicating that micro-environmental

  14. DISTANCE OF SPREAD OF ASIAN CITRUS CANKER FROM SOURCE OF INFECTION IN COMMERCIAL PLANTINGS IN SAO PAULO, BRAZIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas axonopodis pv. citri (Xac)-infected trees continued to occur in São Paulo commercial plantings previously subjected to eradication, indicating that removing all trees within a 30-m radius of known Xac-infected trees was insufficient to eradicate the disease within infected orchards. Pos...

  15. Alternative methods for the control of postharvest citrus diseases.

    PubMed

    Talibi, I; Boubaker, H; Boudyach, E H; Ait Ben Aoumar, A

    2014-07-01

    The postharvest diseases of citrus fruit cause considerable losses during storage and transportation. These diseases are managed principally by the application of synthetic fungicides. However, the increasing concern for health hazards and environmental pollution due to chemical use has required the development of alternative strategies for the control of postharvest citrus diseases. Management of postharvest diseases using microbial antagonists, natural plant-derived products and Generally Recognized As Safe compounds has been demonstrated to be most suitable to replace the synthetic fungicides, which are either being banned or recommended for limited use. However, application of these alternatives by themselves may not always provide a commercially acceptable level of control of postharvest citrus diseases comparable to that obtained with synthetic fungicides. To provide more effective disease control, a multifaceted approach based on the combination of different postharvest treatments has been adopted. Actually, despite the distinctive features of these alternative methods, several reasons hinder the commercial use of such treatments. Consequently, research should emphasize the development of appropriate tools to effectively implement these alternative methods to commercial citrus production. PMID:24617532

  16. Canker Sores

    MedlinePLUS

    ... as clusters of very small ulcers (less than a millimeter in some cases) that sometimes merge together to form larger ulcers. They usually heal in just over one week. Most of the time, canker sores are self-limiting. This means that they will go away even ...

  17. 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...

  18. Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), vector of citrus huanglongbing disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an important pest of citrus because it transmits phloem-limited bacteria [Candidatus Liberibacter spp., notably Ca. L. asiaticus (Las)], associated with huanglongbing (HLB; citrus greening), currently considered the...

  19. Management Of Citrus Diseases Caused By Phytophthora Spp

    Microsoft Academic Search

    Santa Olga Cacciola; Gaetano Magnano di San Lio

    The complex of citrus diseases caused by Phytophthora spp. is reviewed, with reference to the damages caused by Phytophtora root rot, gummosis and brown rot of fruits. Some aspects\\u000a of the biology and ecology of P. citrophthora and P. nicotianae are revised, like the inoculum dissemination, the fungus reproduction and epidemiology. The symptomatic diagnosis of main\\u000a diseases like foot rot

  20. Over the past 50 years, citrus growers have faced exotic pests and diseases predicted to cause the collapse of the Florida citrus

    E-print Network

    Jawitz, James W.

    Over the past 50 years, citrus growers have faced exotic pests and diseases predicted to cause the collapse of the Florida citrus industry. Through research and changes to management practices, the industry has continued to thrive. However, in 2005 a new disease, citrus greening, was confirmed in Florida

  1. Effect of Citrus Stubborn Disease on Navel Orange Production in a Commercial Orchard in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of citrus stubborn disease (CSD), caused by Spiroplasma citri, on citrus is not fully understood or quantified. The objective of this work was to measure the impact of S. citri infection on citrus production and assess bacterial distribution in trees differing in symptom severity. Infecte...

  2. HUANGLONGBING: A DESTRUCTIVE, NEWLY-EMERGING, CENTURY-OLD DISEASE OF CITRUS 1

    Microsoft Academic Search

    J. M. Bové; Adhemar Pereira de Barros

    2006-01-01

    SUMMARY A detailed account is given of the history, aetiology, biology, epidemiology, detection, geographical distribu- tion, and control of huanglongbing (HLB), a destructive disease of citrus that represents a major threat to the world citrus industry, and is slowly invading new citrus- growing areas. HLB, whose name in Chinese means \\

  3. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Commercial citrus-producing areas. 301.75-5...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The...

  4. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...Funds for the replacement of certified citrus nursery stock. 301.75-17 Section...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...Funds for the replacement of certified citrus nursery stock. Subject to the...

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

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Commercial citrus-producing areas. 301.75-5...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The...

  6. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...Funds for the replacement of certified citrus nursery stock. 301.75-17 Section...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...Funds for the replacement of certified citrus nursery stock. Subject to the...

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

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Commercial citrus-producing areas. 301.75-5...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The...

  8. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Funds for the replacement of certified citrus nursery stock. 301.75-17 Section...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...Funds for the replacement of certified citrus nursery stock. Subject to the...

  9. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...Funds for the replacement of certified citrus nursery stock. 301.75-17 Section...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...Funds for the replacement of certified citrus nursery stock. Subject to the...

  10. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Funds for the replacement of certified citrus nursery stock. 301.75-17 Section...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...Funds for the replacement of certified citrus nursery stock. Subject to the...

  11. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Commercial citrus-producing areas. 301.75-5...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The...

  12. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Commercial citrus-producing areas. 301.75-5...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The...

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

    PubMed

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

    2014-02-01

    Thousand cankers disease, caused by the walnut twig beetle (Pityophthorus juglandis Blackman) and an associated fungal pathogen (Geosmithia morbida M. Kolarík, E. Freeland, C. Utley, and N. Tisserat), threatens the health and commercial use of eastern black walnut (Juglans nigra L.), one of the most economically valuable tree species in the United States. Effective phytosanitary measures are needed to reduce the possibility of spreading this insect and pathogen through wood movement. This study evaluated the efficacy of heat treatments and debarking to eliminate P. juglandis and C. morbida in J. nigra logs 4-18 cm in diameter and 30 cm in length. Infested logs were steam heated until various outer sapwood temperatures (60, 65, and 70 degrees C in 2011; 36, 42, 48, 52, and 56 degrees C in 2012) were maintained or exceeded for 30-40 min. In 2011, all heat treatments eliminated G. morbida from the bark, but logs were insufficiently colonized by P. juglandis to draw conclusions about treatment effects on the beetle. Debarking did not ensure elimination of the pathogen from the sapwood surface. In 2012, there was a negative effect of increasing temperature on P. juglandis emergence and G. morbida recovery. G. morbida did not survive in logs exposed to treatments in which minimum temperatures were 48 degrees C or higher, and mean P. juglandis emergence decreased steadily to zero as treatment minimum temperature increased from 36 to 52 degrees C. A minimum outer sapwood temperature of 56 degrees C maintained for 40 min is effective for eliminating the thousand cankers disease vector and pathogen from walnut logs, and the current heat treatment schedule for the emerald ash borer (60 degrees C core temperature for 60 min) is more than adequate for treating P. juglandis and G. morbida in walnut firewood. PMID:24665700

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

    PubMed

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

    2014-05-01

    The main objectives of this study were to evaluate genetic composition of Geosmithia morbida populations in the native range of black walnut and provide a better understanding regarding demography of the pathogen. The fungus G. morbida, and the walnut twig beetle, Pityophthorus juglandis, have been associated with a disease complex of black walnut (Juglans nigra) known as thousand cankers disease (TCD). The disease is manifested as branch dieback and canopy loss, eventually resulting in tree death. In 2010, the disease was detected in black walnut in Tennessee, and subsequently in Virginia and Pennsylvania in 2011 and North Carolina in 2012. These were the first incidences of TCD east of Colorado, where the disease has been established for more than a decade on indigenous walnut species. A genetic diversity and population structure study of 62 G. morbida isolates from Tennessee, Pennsylvania, North Carolina and Oregon was completed using 15 polymorphic microsatellite loci. The results revealed high haploid genetic diversity among seven G. morbida populations with evidence of gene flow, and significant differentiation among two identified genetic clusters. There was a significant correlation between geographic and genetic distance. Understanding the genetic composition and demography of G. morbida can provide valuable insight into recognizing factors affecting the persistence and spread of an invasive pathogen, disease progression, and future infestation predictions. Overall, these data support the hypotheses of two separate, highly diverse pathogen introductions into the native range of black walnut. PMID:24177436

  16. Hosts and Potential Hosts of Citrus Pests and Diseases in the U.S. Authors: Amanda Saville, Alexander Krings, and Tracy Kahn

    E-print Network

    Krings, Alexander

    Citrus ID Hosts and Potential Hosts of Citrus Pests and Diseases in the U.S. Authors: Amanda identification tool, Citrus ID: Hosts and Potential Hosts of Citrus Pests and Diseases in the U.S., devel- oped-Riverside. This online tool is designed to support the identification of host material during citrus pest and disease

  17. Citrus.

    PubMed

    Orbovi?, Vladimir; Grosser, Jude W

    2006-01-01

    Since the initial reports on production of transgenic Citrus via Agrobacterium-mediated transformation, significant progress has been made, and many steps of this procedure using the juvenile tissue explants have been improved. Abundant availability of starting material and relative simplicity make this procedure an attractive choice for many researchers despite transformation efficiency that is in the low range of about 1%. Variety of available Agrobacterium strains and reporter/selection genes further facilitate the work by allowing careful planning of experiments in which many steps can be adjusted towards a particular Citrus cultivar. With the use of this procedure, genetically transformed grapefruit, oranges, lime, and rootstock cultivars are routinely produced while some difficulties persist in efforts to transform lemon and especially mandarin cultivars. PMID:17033062

  18. AN EVOLUTIONARY PERSPECTIVE OF XYELLAE DISEASES IN GRAPEVIN, CITRUS AND MULBERRY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xylella fastidiosa causes diseases on many economically important plants. An understanding of how xylellae diseases originated and evolved is interesting as well as important for disease prevention and management. We evaluated the phylogenetic relationships among strains from citrus, grapevine, and ...

  19. Implications of Climate Change for Toxoptera citricida (Kirkaldy), a Disease Vector of Citrus in Florida

    Microsoft Academic Search

    Jawwad A. Qureshi

    \\u000a Increasing temperatures, elevated CO2 levels, and changes in rainfall patterns are predicted to impact plants and insects, both harmful and beneficial. Toxoptera citricida Kirkaldy (Homoptera: Aphididae), commonly known as the brown citrus aphid (BrCA), is a cosmopolitan pest of citrus and a\\u000a highly efficient vector of citrus tristeza virus (CTV). Both the pest and the disease pose a serious threat

  20. Novel demonstration of RNAi in citrus reveals importance of citrus callose synthase in defence against Xanthomonas citri subsp. citri.

    PubMed

    Enrique, Ramón; Siciliano, Florencia; Favaro, María Alejandra; Gerhardt, Nadia; Roeschlin, Roxana; Rigano, Luciano; Sendin, Lorena; Castagnaro, Atilio; Vojnov, Adrian; Marano, María Rosa

    2011-04-01

    Citrus is an economically important fruit crop that is severely afflicted by citrus canker, a disease caused by the bacterial phytopathogen, Xanthomonas citri subsp. citri (Xcc). GenBank houses a large collection of Expressed Sequence Tags (ESTs) enriched with transcripts generated during the defence response against this pathogen; however, there are currently no strategies in citrus to assess the function of candidate genes. This has greatly limited research as defence signalling genes are often involved in multiple pathways. In this study, we demonstrate the efficacy of RNA interference (RNAi) as a functional genomics tool to assess the function of candidate genes involved in the defence response of Citrus limon against the citrus canker pathogen. Double-stranded RNA expression vectors, encoding hairpin RNAs for citrus host genes, were delivered to lemon leaves by transient infiltration with transformed Agrobacterium. As proof of principle, we have established silencing of citrus phytoene desaturase (PDS) and callose synthase (CalS1) genes. Phenotypic and molecular analyses showed that silencing vectors were functional not only in lemon plants but also in other species of the Rutaceae family. Using silencing of CalS1, we have demonstrated that plant cell wall-associated defence is the principal initial barrier against Xanthomonas infection in citrus plants. Additionally, we present here results that suggest that H?O? accumulation, which is suppressed by xanthan from Xcc during pathogenesis, contributes to inhibition of xanthan-deficient Xcc mutant growth either in wild-type or CalS1-silenced plants. With this work, we have demonstrated that high-throughput reverse genetic analysis is feasible in citrus. PMID:20809929

  1. Transcriptome Profiling of Citrus Fruit Response to Huanglongbing Disease

    PubMed Central

    Martinelli, Federico; Uratsu, Sandra L.; Albrecht, Ute; Reagan, Russell L.; Phu, My L.; Britton, Monica; Buffalo, Vincent; Fass, Joseph; Leicht, Elizabeth; Zhao, Weixiang; Lin, Dawei; D'Souza, Raissa; Davis, Cristina E.; Bowman, Kim D.; Dandekar, Abhaya M.

    2012-01-01

    Huanglongbing (HLB) or “citrus greening” is the most destructive citrus disease worldwide. In this work, we studied host responses of citrus to infection with Candidatus Liberibacter asiaticus (CaLas) using next-generation sequencing technologies. A deep mRNA profile was obtained from peel of healthy and HLB-affected fruit. It was followed by pathway and protein-protein network analysis and quantitative real time PCR analysis of highly regulated genes. We identified differentially regulated pathways and constructed networks that provide a deep insight into the metabolism of affected fruit. Data mining revealed that HLB enhanced transcription of genes involved in the light reactions of photosynthesis and in ATP synthesis. Activation of protein degradation and misfolding processes were observed at the transcriptomic level. Transcripts for heat shock proteins were down-regulated at all disease stages, resulting in further protein misfolding. HLB strongly affected pathways involved in source-sink communication, including sucrose and starch metabolism and hormone synthesis and signaling. Transcription of several genes involved in the synthesis and signal transduction of cytokinins and gibberellins was repressed while that of genes involved in ethylene pathways was induced. CaLas infection triggered a response via both the salicylic acid and jasmonic acid pathways and increased the transcript abundance of several members of the WRKY family of transcription factors. Findings focused on the fruit provide valuable insight to understanding the mechanisms of the HLB-induced fruit disorder and eventually developing methods based on small molecule applications to mitigate its devastating effects on fruit production. PMID:22675433

  2. Cryphonectria canker on Tibouchina in Colombia By M. J. WINGFIELD

    E-print Network

    canker disease on Tibouchina spp. (Melastomataceae) in Colombia. We used morphological studies on Tibouchina urvilleana (DC). Logn. (Melastomataceae), which is native to Brazil. In a subsequent survey

  3. Citrus Cachexia Viroid, a New Viroid of Citrus: Relationship to Viroids of the Exocortis Disease Complex

    Microsoft Academic Search

    J. S. Semancik; C. N. Roistacher; R. Rivera-Bustamante; N. Duran-Vila

    1988-01-01

    SUMMARY Recovery of highly purified citrus cachexia viroid (CCaV) was accomplished by serial elution following CF-11 cellulose chromatography of a 2 i-LiCl-soluble nucleic acid preparation. The alternative herbaceous host, cucumber (Cucumis sativus cv. Suyo), yielded greater quantities of the viroid than the highest yielding citrus host, citron (Citrus medica cv. Etrog). A randomly primed cDNA probe to CCaV purified from

  4. Twelve polymorphic microsatellite loci from the Asian Citrus Psyllid, Diaphorina citri Kuwayama, the vector for citrus greening disease Huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Twelve polymorphic microsatellite markers were developed from microsatellite-enriched DNA libraries and mined from an EST library of Diaphorina citri, the vector of the devastating citrus greening disease (Huanglongbing). Analysis of 288 individuals from Florida, Texas, and Brazil showed allelic di...

  5. Influence of rootstock variety on huanglongbing disease development in field-grown sweet orange (Citrus sinensis L.) osbeck trees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), a bacterial disease of citrus, is causing substantial economic losses to the citrus industry worldwide. Sweet oranges are highly susceptible to the disease, and account for nearly 90% of all varieties grown in Florida. Rootstock is an important component of commercial citrus p...

  6. PCR-based Detection of Spiroplasma citri Associated with Citrus Stubborn Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    PCR detection of Spiroplasma citri, the causal agent of citrus stubborn disease, was improved using primers based on sequences of the P89 adhesin gene and the P58 putative adhesin multigene of S. citri. PCR was compared with isolation by culturing for detection of S. citri in two 20 A citrus orchar...

  7. PCR detection of the two «Candidatus» liberobacter species associated with greening disease of citrus

    Microsoft Academic Search

    Sandrine Jagoueix; Joseph Marie Bové; Monique Garnier

    1996-01-01

    Greening is a severe and widespread disease of citrus in two main citrus growing areas of the world, Asia and Africa. It is caused by an uncultured phloem restricted bacterium that we have recently characterized from the sequence of its 16S ribosomal DNA. The bacterium is a new«Candidatus»genus, Liberobacter, in the alpha subdivision of the proteobacteria, and two «Candidatus species»

  8. 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...

  9. 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...

  10. Population Structure of Geosmithia morbida, the Causal Agent of Thousand Cankers Disease of Walnut Trees in the United States

    PubMed Central

    Graves, Andrew D.; Hartel, Colleen; Pscheidt, Jay W.; Tonos, Jadelys; Broders, Kirk; Cranshaw, Whitney; Seybold, Steven J.; Tisserat, Ned

    2014-01-01

    The ascomycete Geosmithia morbida and the walnut twig beetle Pityophthorus juglandis are associated with thousand cankers disease of Juglans (walnut) and Pterocarya (wingnut). The disease was first reported in the western United States (USA) on several Juglans species, but has been found more recently in the eastern USA in the native range of the highly susceptible Juglans nigra. We performed a comprehensive population genetic study of 209 G. morbida isolates collected from Juglans and Pterocarya from 17 geographic regions distributed across 12 U.S. states. The study was based on sequence typing of 27 single nucleotide polymorphisms from three genomic regions and genotyping with ten microsatellite primer pairs. Using multilocus sequence-typing data, 197 G. morbida isolates were placed into one of 57 haplotypes. In some instances, multiple haplotypes were recovered from isolates collected on the same tree. Twenty-four of the haplotypes (42%) were recovered from more than one isolate; the two most frequently occurring haplotypes (H02 and H03) represented 36% of all isolates. These two haplotypes were abundant in California, but were not recovered from Arizona or New Mexico. G. morbida population structure was best explained by four genetically distinct groups that clustered into three geographic regions. Most of the haplotypes isolated from the native range of J. major (Arizona and New Mexico) were found in those states only or present in distinct genetic clusters. There was no evidence of sexual reproduction or genetic recombination in any population. The scattered distribution of the genetic clusters indicated that G. morbida was likely disseminated to different regions at several times and from several sources. The large number of haplotypes observed and the genetic complexity of G. morbida indicate that it evolved in association with at least one Juglans spp. and the walnut twig beetle long before the first reports of the disease. PMID:25393300

  11. Population structure of Geosmithia morbida, the causal agent of thousand cankers disease of walnut trees in the United States.

    PubMed

    Zerillo, Marcelo M; Ibarra Caballero, Jorge; Woeste, Keith; Graves, Andrew D; Hartel, Colleen; Pscheidt, Jay W; Tonos, Jadelys; Broders, Kirk; Cranshaw, Whitney; Seybold, Steven J; Tisserat, Ned

    2014-01-01

    The ascomycete Geosmithia morbida and the walnut twig beetle Pityophthorus juglandis are associated with thousand cankers disease of Juglans (walnut) and Pterocarya (wingnut). The disease was first reported in the western United States (USA) on several Juglans species, but has been found more recently in the eastern USA in the native range of the highly susceptible Juglans nigra. We performed a comprehensive population genetic study of 209 G. morbida isolates collected from Juglans and Pterocarya from 17 geographic regions distributed across 12 U.S. states. The study was based on sequence typing of 27 single nucleotide polymorphisms from three genomic regions and genotyping with ten microsatellite primer pairs. Using multilocus sequence-typing data, 197 G. morbida isolates were placed into one of 57 haplotypes. In some instances, multiple haplotypes were recovered from isolates collected on the same tree. Twenty-four of the haplotypes (42%) were recovered from more than one isolate; the two most frequently occurring haplotypes (H02 and H03) represented 36% of all isolates. These two haplotypes were abundant in California, but were not recovered from Arizona or New Mexico. G. morbida population structure was best explained by four genetically distinct groups that clustered into three geographic regions. Most of the haplotypes isolated from the native range of J. major (Arizona and New Mexico) were found in those states only or present in distinct genetic clusters. There was no evidence of sexual reproduction or genetic recombination in any population. The scattered distribution of the genetic clusters indicated that G. morbida was likely disseminated to different regions at several times and from several sources. The large number of haplotypes observed and the genetic complexity of G. morbida indicate that it evolved in association with at least one Juglans spp. and the walnut twig beetle long before the first reports of the disease. PMID:25393300

  12. 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...

  13. First report of Neofusicoccum parvum causing canker and die-back of Eucalyptus in Spain

    E-print Network

    First report of Neofusicoccum parvum causing canker and die-back of Eucalyptus in Spain Eugenia disease in Eucalyptus globulus in North Spain. Keywords Eucalyptus canker. Neofusicoccum parvum . Botryosphaeriaceae A canker disease outbreak was observed for the first time on Eucalyptus globulus in North Spain

  14. First outbreak of pitch canker in a South African pine plantation

    Microsoft Academic Search

    T. A. Coutinho; E. T. Steenkamp; K. Mongwaketsi; M. Wilmot; M. J. Wingfield

    2007-01-01

    Fusarium circinatum, the causal agent of pitch canker, was first reported in South Africa in 1990 on Pinus patula seedlings in a nursery. Subsequent to this outbreak the pathogen has spread throughout South African pine nurseries causing\\u000a a serious root and collar rot disease of various Pinus spp. The stem canker disease on plantation trees that typifies pitch canker in

  15. Nutritional deficiency in citrus with symptoms of citrus variegated chlorosis disease.

    PubMed

    Silva-Stenico, M E; Pacheco, F T H; Pereira-Filho, E R; Rodrigues, J L M; Souza, A N; Etchegaray, A; Gomes, J E; Tsai, S M

    2009-08-01

    It is well known that citrus plants that have been infected by Xylella fastidiosa display nutritional deficiencies, probably caused by production of extracellular polymers by the bacteria that block normal nutrient flow through the xylem. The aim of this work was to study the mineral composition of specific foliar areas in different stages of infection in citrus. Thus, the concentrations of macro and micronutrients in leaves of citrus infected by X. fastidiosa were measured. Samples from four infected citrus orchards in the State of São Paulo, Brazil, were respectively collected from Santa Rita do Passa Quatro, Neves Paulista, Gavião Peixoto and Paraíso counties. The presence of X. fastidiosa in leaves was confirmed by polymerase chain reaction (PCR) using specific PCR primers. To understand the variation in leaf-nutrient content in citrus plants, we used foliar nutrient values from control (non-symptomatic) plants as a reference. Chemometric analysis showed that the deficiency of P and K in symptomatic trees for all orchards and high concentrations of Fe, Mn and Zn were observed in chlorotic areas, although other studies revealed deficiency of zinc in leaves. This is the first report showing that a correlation between chlorotic citrus leaf and higher concentrations of Fe, Mn and Zn are observed when infected and healthy plants were compared. PMID:19802445

  16. Citrus Diseases Exotic to Florida: Black Spot1 K.-R. Chung, N. A. Peres and L. W. Timmer2

    E-print Network

    Jawitz, James W.

    PP 213 Citrus Diseases Exotic to Florida: Black Spot1 K.-R. Chung, N. A. Peres and L. W. Timmer2 1.-R. Chung, associate professor, Plant Pathology Department, Citrus REC, Lake Alfred, Florida; N.A. Peres, assistant professor, Gulf Coast REC, Balm, Florida; and L.W. Timmer, professor emeritus, Citrus REC, Lake

  17. Phylogeography of the Walnut Twig Beetle, Pityophthorus juglandis, the Vector of Thousand Cankers Disease in North American Walnut Trees

    PubMed Central

    Rugman-Jones, Paul F.; Seybold, Steven J.; Graves, Andrew D.; Stouthamer, Richard

    2015-01-01

    Thousand cankers disease (TCD) of walnut trees (Juglans spp.) results from aggressive feeding in the phloem by the walnut twig beetle (WTB), Pityophthorus juglandis, accompanied by inoculation of its galleries with a pathogenic fungus, Geosmithia morbida. In 1960, WTB was only known from four U.S. counties (in Arizona, California, and New Mexico), but the species has now (2014) invaded over 115 counties, representing much of the western USA, and at least six states in the eastern USA. The eastern expansion places TCD in direct proximity to highly valuable (> $500 billion) native timber stands of eastern black walnut, Juglans nigra. Using mitochondrial DNA sequences, from nearly 1100 individuals, we examined variation among 77 samples of WTB populations across its extended range in the USA, revealing high levels of polymorphism and evidence of two divergent lineages. The highest level of genetic diversity for the different lineages was found in the neighboring Madrean Sky Island and Western New Mexico regions, respectively. Despite their proximity, there was little evidence of mixing between these regions, with only a single migrant detected among 179 beetles tested. Indeed, geographic overlap of the two lineages was only common in parts of Colorado and Utah. Just two haplotypes, from the same lineage, predominated over the vast majority of the recently expanded range. Tests for Wolbachia proved negative suggesting it plays no role in "driving" the spread of particular haplotypes, or in maintaining deep levels of intraspecific divergence in WTB. Genotyping of ribosomal RNA corroborated the mitochondrial lineages, but also revealed evidence of hybridization between them. Hybridization was particularly prevalent in the sympatric areas, also apparent in all invaded areas, but absent from the most haplotype-rich area of each mitochondrial lineage. Hypotheses about the specific status of WTB, its recent expansion, and potential evolutionary origins of TCD are discussed. PMID:25695760

  18. Phylogeography of the Walnut Twig Beetle, Pityophthorus juglandis, the Vector of Thousand Cankers Disease in North American Walnut Trees.

    PubMed

    Rugman-Jones, Paul F; Seybold, Steven J; Graves, Andrew D; Stouthamer, Richard

    2015-01-01

    Thousand cankers disease (TCD) of walnut trees (Juglans spp.) results from aggressive feeding in the phloem by the walnut twig beetle (WTB), Pityophthorus juglandis, accompanied by inoculation of its galleries with a pathogenic fungus, Geosmithia morbida. In 1960, WTB was only known from four U.S. counties (in Arizona, California, and New Mexico), but the species has now (2014) invaded over 115 counties, representing much of the western USA, and at least six states in the eastern USA. The eastern expansion places TCD in direct proximity to highly valuable (> $500 billion) native timber stands of eastern black walnut, Juglans nigra. Using mitochondrial DNA sequences, from nearly 1100 individuals, we examined variation among 77 samples of WTB populations across its extended range in the USA, revealing high levels of polymorphism and evidence of two divergent lineages. The highest level of genetic diversity for the different lineages was found in the neighboring Madrean Sky Island and Western New Mexico regions, respectively. Despite their proximity, there was little evidence of mixing between these regions, with only a single migrant detected among 179 beetles tested. Indeed, geographic overlap of the two lineages was only common in parts of Colorado and Utah. Just two haplotypes, from the same lineage, predominated over the vast majority of the recently expanded range. Tests for Wolbachia proved negative suggesting it plays no role in "driving" the spread of particular haplotypes, or in maintaining deep levels of intraspecific divergence in WTB. Genotyping of ribosomal RNA corroborated the mitochondrial lineages, but also revealed evidence of hybridization between them. Hybridization was particularly prevalent in the sympatric areas, also apparent in all invaded areas, but absent from the most haplotype-rich area of each mitochondrial lineage. Hypotheses about the specific status of WTB, its recent expansion, and potential evolutionary origins of TCD are discussed. PMID:25695760

  19. Odor coding in a disease-transmitting herbivorous insect, the Asian citrus psyllid.

    PubMed

    Coutinho-Abreu, Iliano V; McInally, Shane; Forster, Lisa; Luck, Robert; Ray, Anandasankar

    2014-07-01

    Olfactory systems discriminate odorants very efficiently and herbivorous insects use them to find hosts in confounding and complex odor landscapes. The Asian citrus psyllid (ACP), Diaphorina citri, feeds on citrus flush and transmits Candidatus Liberibacter that causes citrus greening disease globally. Here, we perform a systematic analysis of odor detection in the ACP antenna using single-unit electrophysiology of rhinarial plate sensilla to a large panel of odorants from plants. We identify neurons that respond strongly to odorants found in the host citrus plants. Comparisons with the generalist yeast-feeding Drosophila melanogaster and specialist anthropophilic Anopheles gambiae reveal differences in odor-coding strategies for the citrus-seeking ACP. These findings provide a foundation for understanding host-odor coding in herbivorous insects. PMID:24904081

  20. Candidate gene markers for Candidatus Liberibacter asiaticus for detecting citrus greening disease.

    PubMed

    Nageswara-Rao, Madhugiri; Irey, Mike; Garnsey, Stephen M; Gowda, Siddarame

    2013-06-01

    Citrus Huanglongbing (HLB) also known as citrus greening is one of the most devastating diseases of citrus worldwide. The disease is caused by Candidatus Liberibacter bacterium, vectored by the psyllid Diaphorina citri Kuwayama and Trioza erytreae Del Guercio. Citrus plants infected by the HLB bacterium may not show visible symptoms sometimes for years following infection. The aim of this study was to develop effective gene-specific primer pairs for polymerase chain reaction based method for quick screening of HLB disease. Thirty-two different gene-specific primer pairs, across the Ca. Liberibacter asiaticus genome, were successfully developed. The possibility of these primer pairs for cross-genome amplification across 'Ca. Liberibacter africanus' and 'Ca. Liberibacter americanus' were tested. The applicability of these primer pairs for detection and differentiation of Ca Liberibacter spp. is discussed. PMID:23660656

  1. Detection of a phytoplasma in citrus showing Huanglongbing (yellow shoot disease) symptoms in Guangdong, P. R. China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus Huanglongbing (HLB) or yellow shoot disease (ex. greening disease) is highly destructive to citrus production worldwide. Understanding the etiology of HLB is critical for managing the disease. HLB is currently known to be associated with infection by Candidatus Liberibacter asiaticus in China...

  2. CITRUS AND COFFEE STRAINS OF XYLELLA FASTIDIOSA INDUCE PIERCES DISEASE IN GRAPEVINE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xylella fastidiosa causes citrus variegated chlorosis disease in Brazil and Pierces Disease of grapevines in the United States. Both of these diseases cause significant production problems in the respective industries. The recent establishment of the glassy-winged sharpshooter in California has ra...

  3. CITRUS AND COFFEE STRAINS OF XYELLA FASTIDIOSA INDUCE PIERCE'S DISEASE IN GRAPEVINE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xyella fastidiosa causes Citrus Varigated Chlorosis (CVC) and Coffee Leaf Scorch (CLS) diseases in Brazil and Pierce's Disease (PD) of grapvine in the United States. All three diseases cause significant production problems in the respective industries. The recent establishment of the glassy-winged...

  4. CITRUS AND COFFEE STRAINS OF XYELLA FASTIDIOSA INDUCE PIERCE'S DISEASE IN GRAPEVINE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xylella fastidiosa causes Citrus Variegated Chlorosis Disease in Brazil and Pierce¿s Disease of grapevines in the United States. Both of these diseases cause significant production problems in the respective industries. The recent establishment of the glassy-winged sharpshooter in California has r...

  5. 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...

  6. Molecular, ecological and evolutionary approaches to understanding Alternaria diseases of citrus.

    PubMed

    Akimitsu, Kazuya; Peever, Tobin L; Timmer, L W

    2003-11-01

    SUMMARY Alternaria fungi cause four different diseases of citrus: Alternaria brown spot of tangerines, Alternaria leaf spot of rough lemon, Alternaria black rot of several citrus fruits and Mancha foliar of Mexican lime. The first three diseases are caused by the small-spored species, Alternaria alternata and the causal agents can only be differentiated using pathogenicity tests, toxin assays or genetic markers. Mancha foliar is caused by the morphologically distinct, large-spored species A. limicola. Substantial progress has been made in understanding the biology, ecology, population biology, systematics, molecular biology and biochemistry of the interactions between these pathogens and citrus. Epidemiological studies have focused on brown spot of tangerines and their hybrids and have contributed to the development of a model of disease development which has improved control and reduced fungicide use. Studies of the population genetics, host specificity and ecology of A. alternata from different ecological niches on citrus have revealed host specific forms of the pathogen which cause disease on different citrus species, the existence of three phylogenetic lineages of the fungus which cause brown spot world-wide, and closely related non-pathogenic isolates which colonize healthy citrus tissue. The role of host-specific toxins in Alternaria diseases of citrus has been extensively studied for over 20 years, and these pathosystems have become model systems for host-pathogen interactions. Recent molecular research has started to unravel the genetic basis of toxin production and the host susceptibility to toxin, and the role of extracellular, degradative enzymes in disease. PMID:20569403

  7. New excised-leaf assay method to test inoculativity of Asian citrus psyllid (Hemiptera: Psyllidae) with Candidatus Liberibacter asiaticus associated with citrus huanglongbing disease.

    PubMed

    Ammar, El-Desouky; Walter, Abigail J; Hall, David G

    2013-02-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the primary vector of Candidatus Liberibacter asiaticus (Las) associated with huanglongbing, or citrus greening, the most devastating citrus (Citrus spp.) disease worldwide. Here, we developed a new "excised-leaf assay" that can speed up Las-inoculativity tests on Asian citrus psyllid from the current 3-12 mo (when using whole citrus seedlings for inoculation) to only 2-3 wk. Young adults of Asian citrus psyllid that had been reared on Las-infected plants were caged on excised healthy sweet orange [Citrus sinensis (L.) Osbeck] leaves for a 1-2-wk inoculation access periods (IAP), and then both psyllids and leaves were tested later by quantitative polymerase chain reaction (PCR). When single adults were tested per leaf, percentages of Las-positive leaves averaged 2-6% by using HLBaspr primers and 10-20% by using the more sensitive LJ900 primers. Higher proportions of Las-positive leaves were obtained with 1) higher densities of inoculating psyllids (5-10 adults per leaf), 2) longer IAPs, and 3) incubation of leaves for 1 wk postinoculation before PCR. Logistic regression analysis indicated a positive correlation between Las titer in Asian citrus psyllid adults tested singly and the probability of detecting Las in the inoculated leaves, correlations that can be very useful in epidemiological studies. Comparison between excised leaves and whole seedlings, inoculated consecutively for 1 wk each by one or a group of psyllids, indicated no significant difference between Las detection in excised leaves or whole plants. This new excised-leaf assay method saves considerable time, materials, and greenhouse space, and it may enhance vector relation and epidemiological studies on Las and potentially other Liberibacter spp. associated with huanglongbing disease. PMID:23448011

  8. 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...

  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. 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

  11. Short distance dispersal of splashed bacteria of Xanthomonas citri subsp. citri from canker-infected grapefruit tree canopies in turbulent wind

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp citri [Xcc]) can result in yield loss and market restrictions. The pathogen is dispersed in rain splash and spread is promoted by wind. The goal of this study was to gain some insight into the behavior of the downwind plume of Xcc from ~1.5 m-tall canker-affect...

  12. Physiological and proteomic characterizations of “Candidatus Liberibacter” associated diseases in citrus and potato plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    “Candidatus Liberibacter” species (Lib) are fastidious gram-negative bacteria transmitted by psyllids and associated with citrus huanglongbing (HLB) and potato zebra chip (ZC) diseases. Here, proteomic analyses via 2-DE and mass spectrometry were employed to elucidate protein expression profiles in ...

  13. PCR-based Detection of Spiroplasma Citri Associated with Citrus Stubborn Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Improvements in polymerase chain reaction (PCR) detection of Spiroplasma citri, the causal agent of citrus stubborn disease, made PCR more reliable than culturing for S. citri detection. Primer sequences from the P89 putative adhesin gene, which is present on a plasmid as well as in the S. citri gen...

  14. Cystofilobasidium infirmominiatum as a biocontrol agent of postharvest diseases of apple and citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two psycrotrophic yeasts isolated from the surface of lemons have been selected as biocontrol agents of the most common postharvest diseases of apples and citrus that develops during cold storage. The biocontrol yeasts were identified as Cystofilobasidium infirmominiatum and Leucosporidium scottii....

  15. 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 prokaryote principally vectored by the beet leafhopper (BLH) in California. The objective of this study was to develop a method to estimate incidence of CSD. A 100% sample was compared with a 25% sample collected by a hiera...

  16. Portable fluorescence spectroscopy platform for Huanglongbing (HLB) citrus disease in situ detection

    NASA Astrophysics Data System (ADS)

    Mota, Alessandro D.; Rossi, Giuliano; de Castro, Guilherme Cunha; Ortega, Tiago A.; de Castro N., Jarbas C.

    2014-02-01

    In this work, the development of a portable fluorescence spectroscopy platform for Huanglongbing (HLB) citrus disease in situ detection is presented. The equipment consists of an excitation blue LED light source, a commercial miniature spectrometer and embedded software. Measurements of healthy, HLB-symptomatic and HLB-asymptomatic citrus leafs were performed. Leafs were excited with the blue LED and their fluorescence spectra collected. Embedded electronics and software were responsible for the spectrum processing and classification via partial least squares regression. Global success rates above 80% and 100% distinction of healthy and HLB-symptomatic leafs were obtained.

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

    PubMed

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

    2014-02-01

    Citrus stubborn disease (CSD), first identified in California, is a widespread bacterial disease found in most arid citrus-producing regions in the United States and the Mediterranean Region. The disease is caused by Spiroplasma citri, an insect-transmitted and phloem-colonizing bacterium. CSD causes significant tree damage resulting in loss of fruit production and quality. Detection of CSD is challenging due to low and fluctuating titer and sporadic distribution of the pathogen in infected trees. In this study, we report the development of a novel diagnostic method for CSD using an S. citri-secreted protein as the detection marker. Microbial pathogens secrete a variety of proteins during infection that can potentially disperse systemically in infected plants with the vascular flow. Therefore, their distribution may not be restricted to the pathogen infection sites and could be used as a biological marker for infection. Using mass spectrometry analysis, we identified a unique secreted protein from S. citri that is highly expressed in the presence of citrus phloem extract. ScCCPP1, an antibody generated against this protein, was able to distinguish S. citri-infected citrus and periwinkle from healthy plants. In addition, the antiserum could be used to detect CSD using a simple direct tissue print assay without the need for sample processing or specialized lab equipment and may be suitable for field surveys. This study provides proof of a novel concept of using pathogen-secreted protein as a marker for diagnosis of a citrus bacterial disease and can probably be applied to other plant diseases. PMID:23931112

  18. Identification and Genomic Characterization of a New Virus (Tymoviridae Family) Associated with Citrus Sudden Death Disease

    Microsoft Academic Search

    Walter Maccheroni; Marcos C. Alegria; Christian C. Greggio; Joao Paulo Piazza; Rachel F. Kamla; Paula R. A. Zacharias; Moshe Bar-Joseph; Elliot W. Kitajima; Laura C. Assumpcao; Giovana Camarotte; Jussara Cardozo; Elaine C. Casagrande; Fernanda Ferrari; Sulamita F. Franco; Poliana F. Giachetto; Alessandra Girasol; Hamilton Jordao; V. H. A. Silva; L. C. A. Souza; C. I. Aguilar-Vildoso; A. S. Zanca; P. Arruda; J. P. Kitajima; F. C. Reinach; J. A. Ferro; A. C. R. da Silva

    2005-01-01

    Citrus sudden death (CSD) is a new disease that has killed approximately 1 million orange trees in Brazil. Here we report the identification of a new virus associated with the disease. RNAs isolated from CSD-affected and nonaffected trees were used to construct cDNA libraries. A set of viral sequences present exclusively in libraries of CSD-affected trees was used to obtain

  19. Detection and relative titer of Candidatus Liberibacter asiaticus in the salivary glands and alimentary canal of Diaphorina citri (Hemiptera: Psyllidae) vector of citrus Huanglongbing disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Candidatus Liberibacter asiaticus has been strongly implicated as the causative agent of huanglongbing (HLB), or citrus greening, which is currently the most devastating citrus disease worldwide. In the Americas and Asia, HLB is transmitted by the Asian citrus psyllid Diaphorina citri in a persisten...

  20. Citrus production systems to survive greening – horticultural practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fruit yield is a critical component in the long-term profitability of citrus growers in Florida. Increasingly, two factors outside the control of the growers are forcing Florida citrus growers to re-evaluate the sustainability of their current operations. These factors are: 1) impact of canker and ...

  1. 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

  2. Identification and Genomic Characterization of a New Virus (Tymoviridae Family) Associated with Citrus Sudden Death Disease

    PubMed Central

    Maccheroni, Walter; Alegria, Marcos C.; Greggio, Christian C.; Piazza, João Paulo; Kamla, Rachel F.; Zacharias, Paula R. A.; Bar-Joseph, Moshe; Kitajima, Elliot W.; Assumpção, Laura C.; Camarotte, Giovana; Cardozo, Jussara; Casagrande, Elaine C.; Ferrari, Fernanda; Franco, Sulamita F.; Giachetto, Poliana F.; Girasol, Alessandra; Jordão, Hamilton; Silva, Vitor H. A.; Souza, Leonardo C. A.; Aguilar-Vildoso, Carlos I.; Zanca, Almir S.; Arruda, Paulo; Kitajima, João Paulo; Reinach, Fernando C.; Ferro, Jesus A.; da Silva, Ana C. R.

    2005-01-01

    Citrus sudden death (CSD) is a new disease that has killed approximately 1 million orange trees in Brazil. Here we report the identification of a new virus associated with the disease. RNAs isolated from CSD-affected and nonaffected trees were used to construct cDNA libraries. A set of viral sequences present exclusively in libraries of CSD-affected trees was used to obtain the complete genome sequence of the new virus. Phylogenetic analysis revealed that this virus is a new member of the genus Marafivirus. Antibodies raised against the putative viral coat proteins allowed detection of viral antigens of expected sizes in affected plants. Electron microscopy of purified virus confirmed the presence of typical isometric Marafivirus particles. The screening of 773 affected and nonaffected citrus trees for the presence of the virus showed a 99.7% correlation between disease symptoms and the presence of the virus. We also detected the virus in aphids feeding on affected trees. These results suggest that this virus is likely to be the causative agent of CSD. The virus was named Citrus sudden death-associated virus. PMID:15709023

  3. Expression of Xylella fastidiosa RpfF in Citrus Disrupts Signaling in Xanthomonas citri subsp. citri and Thereby Its Virulence.

    PubMed

    Caserta, R; Picchi, S C; Takita, M A; Tomaz, J P; Pereira, W E L; Machado, M A; Ionescu, M; Lindow, S; De Souza, A A

    2014-11-01

    Xylella fastidiosa and Xanthomonas citri subsp. citri, that cause citrus variegated chlorosis (CVC) and citrus canker diseases, respectively, utilize diffusible signal factor (DSF) for quorum sensing. DSF, produced by RpfF, are similar fatty acids in both organisms, although a different set of genes is regulated by DSF in each species. Because of this similarity, Xylella fastidiosa DSF might be recognized and affect the biology of Xanthomonas citri. Therefore, transgenic Citrus sinensis and Carrizo citrange plants overexpressing the Xylella fastidiosa rpfF were inoculated with Xanthomonas citri and changes in symptoms of citrus canker were observed. X. citri biofilms formed only at wound sites on transgenic leaves and were thicker; however, bacteria were unable to break through the tissue and form pustules elsewhere. Although abundant growth of X. citri occurred at wound sites on inoculated transgenic leaves, little growth was observed on unwounded tissue. Genes in the DFS-responsive core in X. citri were downregulated in bacteria isolated from transgenic leaves. DSF-dependent expression of engA was suppressed in cells exposed to xylem sap from transgenic plants. Thus, altered symptom development appears to be due to reduced expression of virulence genes because of the presence of antagonists of DSF signaling in X. citri in rpfF-expressing plants. PMID:25099341

  4. 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

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

    PubMed

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

    2014-04-20

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

  6. ENHANCED DETECTION AND ISOLATION OF THE WALNUT PATHOGEN BRENNARIA RUBRIFACIENS: CAUSAL AGENT OF DEEP BARK CANKER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deep bark canker (DBC) of walnut is caused by the bacterium Brenneria rubrifaciens which produces the red pigment rubrifacine. This disease of English walnut trees, is characterized by deep vertical cankers which exude sap laden with B. rubrifaciens. Although DBC is not observed on younger trees, ...

  7. World-Wide Importance of Phoma Stem Canker ( Leptosphaeria maculans and L. biglobosa ) on Oilseed Rape ( Brassica napus )

    Microsoft Academic Search

    B. D. L. Fitt; H. Brun; M. J. Barbetti; S. R. Rimmer

    2006-01-01

    Phoma stem canker is an internationally important disease of oilseed rape (Brassica napus, canola, rapeseed), causing serious losses in Europe, Australia and North America. UK losses of €56M per season are estimated\\u000a using national disease survey data and a yield loss formula. Phoma stem canker pathogen populations comprise two main species,\\u000a Leptosphaeria maculans, associated with damaging stem base cankers, and

  8. Fusarium torreyae sp. nov., a pathogen causing canker disease of Florida torreya (Torreya taxifolia), a critically endangered conifer restricted to northern Florida and southwestern Georgia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During a survey for pathogens of Florida torreya (Torreya taxifolia) conducted in 2009, a novel Fusarium species was isolated from cankers affecting this critically endangered conifer whose current range is restricted to northern Florida and southwestern Georgia. Published multilocus molecular phylo...

  9. Small RNA profiling reveals phosphorus deficiency as a contributing factor in symptom expression for citrus huanglongbing disease.

    PubMed

    Zhao, Hongwei; Sun, Ruobai; Albrecht, Ute; Padmanabhan, Chellappan; Wang, Airong; Coffey, Michael D; Girke, Thomas; Wang, Zonghua; Close, Timothy J; Roose, Mikeal; Yokomi, Raymond K; Folimonova, Svetlana; Vidalakis, Georgios; Rouse, Robert; Bowman, Kim D; Jin, Hailing

    2013-03-01

    Huanglongbing (HLB) is a devastating citrus disease that is associated with bacteria of the genus 'Candidatus Liberibacter' (Ca. L.). Powerful diagnostic tools and management strategies are desired to control HLB. Host small RNAs (sRNA) play a vital role in regulating host responses to pathogen infection and are used as early diagnostic markers for many human diseases, including cancers. To determine whether citrus sRNAs regulate host responses to HLB, sRNAs were profiled from Citrus sinensis 10 and 14 weeks post grafting with Ca. L. asiaticus (Las)-positive or healthy tissue. Ten new microRNAs (miRNAs), 76 conserved miRNAs, and many small interfering RNAs (siRNAs) were discovered. Several miRNAs and siRNAs were highly induced by Las infection, and can be potentially developed into early diagnosis markers of HLB. miR399, which is induced by phosphorus starvation in other plant species, was induced specifically by infection of Las but not Spiroplasma citri that causes citrus stubborn-a disease with symptoms similar to HLB. We found a 35% reduction of phosphorus in Las-positive citrus trees compared to healthy trees. Applying phosphorus oxyanion solutions to HLB-positive sweet orange trees reduced HLB symptom severity and significantly improved fruit production during a 3-year field trial in south-west Florida. Our molecular, physiological, and field data suggest that phosphorus deficiency is linked to HLB disease symptomology. PMID:23292880

  10. Small RNA Profiling Reveals Phosphorus Deficiency as a Contributing Factor in Symptom Expression for Citrus Huanglongbing Disease

    PubMed Central

    Zhao, Hongwei; Sun, Ruobai; Jin, Hailing

    2013-01-01

    Huanglongbing (HLB) is a devastating citrus disease that is associated with bacteria of the genus ‘Candidatus Liberibacter’ (Ca. L.). Powerful diagnostic tools and management strategies are desired to control HLB. Host small RNAs (sRNA) play a vital role in regulating host responses to pathogen infection and are used as early diagnostic markers for many human diseases, including cancers. To determine whether citrus sRNAs regulate host responses to HLB, sRNAs were profiled from Citrus sinensis 10 and 14 weeks post grafting with Ca. L. asiaticus (Las)-positive or healthy tissue. Ten new microRNAs (miRNAs), 76 conserved miRNAs, and many small interfering RNAs (siRNAs) were discovered. Several miRNAs and siRNAs were highly induced by Las infection, and can be potentially developed into early diagnosis markers of HLB. miR399, which is induced by phosphorus starvation in other plant species, was induced specifically by infection of Las but not Spiroplasma citri that causes citrus stubborn—a disease with symptoms similar to HLB. We found a 35% reduction of phosphorus in Las-positive citrus trees compared to healthy trees. Applying phosphorus oxyanion solutions to HLB-positive sweet orange trees reduced HLB symptom severity and significantly improved fruit production during a 3-year field trial in south-west Florida. Our molecular, physiological, and field data suggest that phosphorus deficiency is linked to HLB disease symptomology. PMID:23292880

  11. “Candidatus liberibacter sp.”, without koch's postulates completed, can the bacterium be considered as the causal agent of citrus Huanglongbing (yellow shoot disease)?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) or yellow shoot disease is a destructive disease that threatens citrus production worldwide. The emergence of HLB in Sao Paulo, State of Brazil in 2004 and in Florida of the U.S. in 2005 has increased concern in the citrus production community in the USA. Intensive research is cu...

  12. Next generation 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 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...

  13. Psyllids as A Tool in Evaluating the Efficiency of Different Management Practices for Control of Citrus Huanglongbing Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), or citrus greening disease, was found in Brazil in 2004. Two species of bacteria, Candidatus Liberibacter asiaticus and Ca. L. americanus, have been identified in Brazil. The disease has not been effectively managed anywhere in the world so far. This is probably because of long ...

  14. Detection of phytoplasma and Candidatus Liberibacter asiaticus in citrus showing Huanglongbing (yellow shoot disease) symptoms in Guangdong, P. R. China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) or yellow shoot disease (ex. greening disease) is highly destructive to citrus production worldwide. HLB is currently known to be associated with Candidatus Liberibacter asiaticus in China. However, Koch’s postulates have not been fulfilled. It also remains unclear if other plant...

  15. 112 2010 USDA Research Forum on Invasive Species GTR-NRS-P-75 THOUSAND CANKERS PATHWAY ASSESSMENT: MOVEMENT OF

    E-print Network

    vector is the walnut twig beetle, Pityophthorus juglandis (WTB). The common name for the disease is "thousand cankers" due to the coalescing cankers surrounding multiple beetle entry points. The WTB, Colorado, and New Mexico. The eastern edge of the disease is the Front Range of Colorado. Our objectives

  16. Resistance of Poncirus and Citrus x Poncirus germplam 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 adults transmit phloem-limited bacteria (Candidatus Liberibacter spp.) that are putatively responsible for citrus greening disease (huanglongbing). Host plant resistance ultimately ma...

  17. American Phytopathological Society: Plant Disease Lessons

    NSDL National Science Digital Library

    If Citrus Canker or Apple Scab are on your syllabus -- or worse yet, on your trees -- then this is the Web site for you. The APS Education Center has organized this very helpful online guide of plant diseases. Each excerpt is more of an information card than a detailed description, but they are very easy to use and organized well. Each Plant Disease Lesson includes: the name of the disease, the pathogen(s), and the host(s), as well as a clear picture of what an affected plant looks like. There are 17 diseases covered under the subgroups of: fungi and fungus-like organisms, nematodes, prokaryotes, and viruses.

  18. Improved real-time PCR diagnosis of citrus stubborn disease by targeting prophage genes of Spiroplasma citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spiroplasma citri is a phloem-limited bacterium causing citrus stubborn disease (CSD). Isolation and culturing of S. citri is difficult and time consuming. Current detection methods use polymerase chain reaction (PCR) assays with primers developed from sequences of S. citri house-keeping genes. In c...

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

    Microsoft Academic Search

    M. A. Van Sluys; M. C. de Oliveira; C. B. Monteiro-Vitorello; Felipe Rodrigues da Silva

    2003-01-01

    Xylella fastidiosa is a xylem-dwelling, insect-transmitted, gamma-proteobacterium that causes diseases in many plants, including grapevine, citrus, periwinkle, almond, oleander, and coffee. X. fastidiosa has an unusu- ally broad host range, has an extensive geographical distribution throughout the American continent, and induces diverse disease phenotypes. Previous molecular analyses indicated three distinct groups of X. fastidiosa isolates that were expected to be

  20. Phosphonate applied by trunk injection controls stem canker and decreases Phytophthora pod rot (black pod) incidence in cocoa in Sulawesi

    Microsoft Academic Search

    P. J. McMahon; A. Purwantara; A. Wahab; M. Imron; S. Lambert; P. J. Keane; D. I. Guest

    2010-01-01

    Stem canker and Phytophthora pod rot (PPR) or black pod caused by Phytophthora palmivora are serious diseases of cocoa (Theobroma cacao L.) in Sulawesi, Indonesia, causing high yield losses for smallholders, possibly exceeded only by losses due to the cocoa\\u000a pod borer (CPB), Conopomorpha cramerella. Potassium phosphonate (phosphite) applied by trunk injection has been demonstrated to effectively control canker and

  1. Colonization of citrus and citrus-related germplasm by Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a serious and devastating disease of citrus caused by Candidatus Liberibacter spp. and vectored by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). The disease has the potential to greatly limit the production of citrus in Florida and other citrus gr...

  2. 7 CFR 319.19 - Notice of quarantine.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Citrus Canker and Other Citrus Diseases § 319.19 Notice of quarantine...prevent the introduction into the United States of the citrus canker disease (Xanthomonas citri (Hasse)...

  3. 7 CFR 319.19 - Notice of quarantine.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Citrus Canker and Other Citrus Diseases § 319.19 Notice of quarantine...prevent the introduction into the United States of the citrus canker disease (Xanthomonas citri (Hasse)...

  4. 7 CFR 319.19 - Notice of quarantine.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Citrus Canker and Other Citrus Diseases § 319.19 Notice of quarantine...prevent the introduction into the United States of the citrus canker disease (Xanthomonas citri (Hasse)...

  5. 7 CFR 319.19 - Notice of quarantine.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Citrus Canker and Other Citrus Diseases § 319.19 Notice of quarantine...prevent the introduction into the United States of the citrus canker disease (Xanthomonas citri (Hasse)...

  6. 7 CFR 319.19 - Notice of quarantine.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Citrus Canker and Other Citrus Diseases § 319.19 Notice of quarantine...prevent the introduction into the United States of the citrus canker disease (Xanthomonas citri (Hasse)...

  7. INCORPORATION OF DISTANCE-OF-SPREAD CALCULATIONS INTO A WEATHER-BASED MODEL DESCRIBING DISEASE DISTRIBUTION AFTER SEVERE WEATHER EVENTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Florida, Asiatic citrus canker (Xanthomonas axonopodis pv. citri, XAC) has a long history of multiple introductions followed by eradication campaigns. The latest eradication campaign began in 1995 and continued through 2005 until regulatory agencies concluded that citrus canker had spread to the...

  8. Evaluation of fungicides and biocontrol agents against Phomopsis canker of tea under field conditions

    Microsoft Academic Search

    P. Ponmurugan; U. I. Baby

    2007-01-01

    An experiment was conducted to study the efficacy of contact and systemic fungicides and biocontrol agents in controlling\\u000a Phomopsis canker disease of tea under field conditions. Among the various treatments, soil application and wound dressing\\u000a of biocontrol agents was found to be superior to fungicides in controlling Phomopsis canker. Dressing wounds with contact\\u000a fungicides such as copper oxychloride and mancozeb

  9. The Phloem-Limited Bacterium of Greening Disease of Citrus Is a Member of the a Subdivision of the Proteobacteria

    Microsoft Academic Search

    SANDRINE JAGOUEIX; JOSEPH-MARIE BOVE; MONIQUE GARNIER

    1994-01-01

    Using the PCR, we amplified the 16s ribosomal DNAs (rDNAs) of an Asian strain and an African strain of the uncultured, gram-negative, walled, phloem-limited bacterium-like organism (BLO) associated with citrus greening disease. We evaded coamplification of chloroplast 16s rDNA by using restriction enzymes; the chloroplast 16s rDNA was sensitive to BclI digestion and resistant to EcoRI digestion, while the 16s

  10. A phytoplasma related to Candidatus Phytoplasma asteri is associated with citrus showing Huanglongbing (yellow shoot disease) symptoms in Guangdong, P. R. China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) or yellow shoot disease (ex. greening disease) is highly destructive to citrus production worldwide. Understanding the etiology of HLB is critical for managing the disease. HLB is currently known to be associated with infection by Candidatus Liberibacter asiaticus in China. Howev...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-27

    ...the analysis, especially any scientific studies that may be pertinent. Protocol Document...collection can be obtained from Mrs. Celeste Sickles, APHIS' Information Collection Coordinator...interim rule, please contact Mrs. Celeste Sickles, APHIS' Information Collection...

  12. RESEARCH ARTICLE Insecticidal Suppression of Asian Citrus

    E-print Network

    Florida, University of

    RESEARCH ARTICLE Insecticidal Suppression of Asian Citrus Psyllid Diaphorina citri (Hemiptera@ufl.edu Abstract 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

  13. Phoma glomerata (Corda) Wollenw. & Hochapfel a new threat causing cankers on shoots of peach trees in Greece

    Microsoft Academic Search

    Thomas Thomidis; Themis J. Michailides; Efstathia Exadaktylou

    Shoot blights are common diseases of peach trees in Greece. This study is the first report of a shoot blight and canker disease\\u000a of peach in Greece caused by the fungus Phoma glomerata (Corda) Wollenw. & Hochapfel. The pathogen caused distinct cankers with abundant gumming on shoots of peach trees. The rate\\u000a of development of P. glomerata in vitro was

  14. Plant resistance within the Rutaceae to Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  15. Cost-Effective Control of Plant Disease When Epidemiological Knowledge Is Incomplete: Modelling Bahia Bark Scaling of Citrus

    PubMed Central

    Neri, Franco M.; DeSimone, R. Erik; Gilligan, Christopher A.

    2014-01-01

    A spatially-explicit, stochastic model is developed for Bahia bark scaling, a threat to citrus production in north-eastern Brazil, and is used to assess epidemiological principles underlying the cost-effectiveness of disease control strategies. The model is fitted via Markov chain Monte Carlo with data augmentation to snapshots of disease spread derived from a previously-reported multi-year experiment. Goodness-of-fit tests strongly supported the fit of the model, even though the detailed etiology of the disease is unknown and was not explicitly included in the model. Key epidemiological parameters including the infection rate, incubation period and scale of dispersal are estimated from the spread data. This allows us to scale-up the experimental results to predict the effect of the level of initial inoculum on disease progression in a typically-sized citrus grove. The efficacies of two cultural control measures are assessed: altering the spacing of host plants, and roguing symptomatic trees. Reducing planting density can slow disease spread significantly if the distance between hosts is sufficiently large. However, low density groves have fewer plants per hectare. The optimum density of productive plants is therefore recovered at an intermediate host spacing. Roguing, even when detection of symptomatic plants is imperfect, can lead to very effective control. However, scouting for disease symptoms incurs a cost. We use the model to balance the cost of scouting against the number of plants lost to disease, and show how to determine a roguing schedule that optimises profit. The trade-offs underlying the two optima we identify—the optimal host spacing and the optimal roguing schedule—are applicable to many pathosystems. Our work demonstrates how a carefully parameterised mathematical model can be used to find these optima. It also illustrates how mathematical models can be used in even this most challenging of situations in which the underlying epidemiology is ill-understood. PMID:25102099

  16. Cost-effective control of plant disease when epidemiological knowledge is incomplete: modelling Bahia bark scaling of citrus.

    PubMed

    Cunniffe, Nik J; Laranjeira, Francisco F; Neri, Franco M; DeSimone, R Erik; Gilligan, Christopher A

    2014-08-01

    A spatially-explicit, stochastic model is developed for Bahia bark scaling, a threat to citrus production in north-eastern Brazil, and is used to assess epidemiological principles underlying the cost-effectiveness of disease control strategies. The model is fitted via Markov chain Monte Carlo with data augmentation to snapshots of disease spread derived from a previously-reported multi-year experiment. Goodness-of-fit tests strongly supported the fit of the model, even though the detailed etiology of the disease is unknown and was not explicitly included in the model. Key epidemiological parameters including the infection rate, incubation period and scale of dispersal are estimated from the spread data. This allows us to scale-up the experimental results to predict the effect of the level of initial inoculum on disease progression in a typically-sized citrus grove. The efficacies of two cultural control measures are assessed: altering the spacing of host plants, and roguing symptomatic trees. Reducing planting density can slow disease spread significantly if the distance between hosts is sufficiently large. However, low density groves have fewer plants per hectare. The optimum density of productive plants is therefore recovered at an intermediate host spacing. Roguing, even when detection of symptomatic plants is imperfect, can lead to very effective control. However, scouting for disease symptoms incurs a cost. We use the model to balance the cost of scouting against the number of plants lost to disease, and show how to determine a roguing schedule that optimises profit. The trade-offs underlying the two optima we identify-the optimal host spacing and the optimal roguing schedule-are applicable to many pathosystems. Our work demonstrates how a carefully parameterised mathematical model can be used to find these optima. It also illustrates how mathematical models can be used in even this most challenging of situations in which the underlying epidemiology is ill-understood. PMID:25102099

  17. 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...

  18. Etiology of three recent diseases of citrus in São Paulo State: sudden death, variegated chlorosis and huanglongbing.

    PubMed

    Bové, Joseph Marie; Ayres, Antonio Juliano

    2007-01-01

    The state of São Paulo (SSP) is the first sweet orange growing region in the world. Yet, the SSP citrus industry has been, and still is, under constant attack from various diseases. In the 1940s, tristeza-quick decline (T-QD) was responsible for the death of 9 million trees in SSP. The causal agent was a new virus, citrus tristeza virus (CTV). The virus was efficiently spread by aphid vectors, and killed most of the trees grafted on sour orange rootstock. Control of the disease resided in replacing sour orange by alternative rootstocks giving tolerant combinations with scions such as sweet orange. Because of its drought resistance, Rangpur lime became the favourite alternative rootstock, and, by 1995, 85% of the SSP sweet orange trees were grafted on this rootstock. Therefore, when in 1999, many trees grafted on Rangpur lime started to decline and suddenly died, the spectre of T-QD seemed to hang over SSP again. By 2003, the total number of dead or affected trees was estimated to be over one million. The new disease, citrus sudden death (CSD), resembles T-QD in several aspects. The two diseases have almost the same symptoms, they spread in time and space in a manner strikingly similar, and the pathological anatomy of the bark at the bud union is alike. Transmission of the CSD agent by graft-inoculation has been obtained with budwood inoculum taken not only on CSD-affected trees (grafted on Rangpur lime), but also on symptomless trees (grafted on Cleopatra mandarin) from the same citrus block. This result shows that symptomless trees on Cleopatra mandarin are tolerant to the CSD agent. Trees on rootstocks such as Sunki mandarin or Swingle citrumelo are also tolerant. Thus, in the CSD-affected region, control consists in replacing Rangpur lime with compatible rootstocks, or in approach-grafting compatible rootstock seedlings to the scions of trees on Rangpur lime (inarching). More than 5 million trees have been inarched in this way. A new disease of sweet orange, citrus variegated chlorosis (CVC), was observed in 1987 in the Triangulo Mineiro of Minas Gerais State and the northern and north-eastern parts of SSP. By 2000, the disease affected already 34% of the 200 million sweet orange trees in SSP. By 2005, the percentage had increased to 43%, and CVC was present in all citrus growing regions of Brazil. Electron microscopy showed that xylem-limited bacteria were present in all symptomatic sweet orange leaves and fruit tissues tested, but not in similar materials from healthy, symptomless trees. Bacteria were consistently cultured from twigs of CVC-affected sweet orange trees but not from twigs of healthy trees. Serological analyses showed the CVC bacterium to be a strain of Xylella fastidiosa. The disease could be reproduced and Koch's postulates fulfilled, by mechanically inoculating a pure culture of X. fastidiosa isolate 8.1.b into sweet orange seedlings. The genome of a CVC strain of X. fastidiosa was sequenced in SSP in the frame of a project supported by FAPESP and Fundecitrus. X. fastidiosa is the first plant pathogenic bacterium, the genome of which has been sequenced. Until recently, America was free of huanglongbing (HLB), but in March 2004 and August 2005, symptoms of the disease were recognized, respectively in the State of São Paulo (SSP) and in Florida, USA. HLB was known in China since 1870 and in South Africa since 1928. Because of its destructiveness and its rapid spread by efficient psyllid insect-vectors, HLB is probably the most serious citrus disease. HLB is caused by a phloem sieve tube-restricted Gram negative bacterium, not yet available in culture. In the 1990s, the bacterium was characterized by molecular techniques as a member of the alpha proteobacteria designated Candidatus Liberibacter africanus for the disease in Africa, and Candidatus Liberibacter asiaticus for HLB in Asia. In SSP, Ca. L. asiaticus is also present, but most of the trees are infected with a new species, Candidatus Liberibacter americanus. PMID:17505974

  19. 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 ...

  20. 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...

  1. Comparative proteomic and metabolomic profiling of citrus fruit with enhancement of disease resistance by postharvest heat treatment

    PubMed Central

    2013-01-01

    Background From field harvest to the consumer’s table, fresh citrus fruit spends a considerable amount of time in shipment and storage. During these processes, physiological disorders and pathological diseases are the main causes of fruit loss. Heat treatment (HT) has been widely used to maintain fruit quality during postharvest storage; however, limited molecular information related to this treatment is currently available at a systemic biological level. Results Mature ‘Kamei’ Satsuma mandarin (Citrus unshiu Marc.) fruits were selected for exploring the disease resistance mechanisms induced by HT during postharvest storage. Proteomic analyses based on two-dimensional gel electrophoresis (2-DE), and metabolomic research based on gas chromatography coupled to mass spectrometry (GC-MS), and liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS) were conducted. The results show resistance associated proteins were up-regulated in heat treated pericarp, such as beta-1, 3-glucanase, Class III chitinase, 17.7?kDa heat shock protein and low molecular weight heat-shock protein. Also, redox metabolism enzymes were down-regulated in heat treated pericarp, including isoflavone reductase, oxidoreductase and superoxide dismutase. Primary metabolic profiling revealed organic acids and amino acids were down-regulated in heat treated pericarp; but significant accumulation of metabolites, including tetradecanoic acid, oleic acid, ornithine, 2-keto-d-gluconic acid, succinic acid, turanose, sucrose, galactose, myo-inositol, glucose and fructose were detected. Noticeably, H2O2 content decreased, while, lignin content increased in heat treated pericarp compared to the control, which might increase fruit resistibility in response to external stress. Also, flavonoids, substances which are well-known to be effective in reducing external stress, were up-regulated in heat treated pericarp. Conclusions This study provides a broad picture of differential accumulation of proteins and metabolites in postharvest citrus fruit, and gives new insights into HT improved fruit disease resistance during subsequent storage of ‘Kamei’ Satsuma mandarin. Interpretation of the data for the proteins and metabolites revealed reactive oxygen species (ROS) and lignin play important roles in heat treatment induced fruit resistance to pathogens and physiological disorders. PMID:23497220

  2. Canker Sores (Aphthous Stomatitis or Recurrent Mouth Ulcers)

    MedlinePLUS

    Canker Sores (Aphthous Stomatitis or Recurrent Mouth Ulcers) What Is It? Symptoms Diagnosis Expected Duration Prevention Treatment When To Call a Professional Prognosis Additional Info What Is It? Canker sores are ...

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

    PubMed

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

    2010-05-26

    Fourier transform infrared (FTIR) spectroscopy has the ability to quickly identify the presence of specific carbohydrates in plant materials. The presence of the disease huanglongbing (HLB) in the leaves of infected citrus plants has a distinctive spectrum that can be used to distinguish an infected plant from a healthy plant. However, many citrus diseases display similar visible symptoms and are of concern to citrus growers. In this study several citrus diseases (citrus leaf rugose virus, citrus tristeza virus, citrus psorosis virus, and Xanthomonas axonopodis ) and nutrient deficiencies (iron, copper, zinc, manganese, and magnesium) were compared with HLB using FTIR spectroscopy to determine if the spectra alone can be used to identify plants that are infected with HLB instead of another disease. The results indicate that the spectra of some diseases and deficiencies more closely resemble those of apparently healthy plants and some share the carbohydrate transformation that has been seen in the spectra of HLB-infected plants. PMID:20438136

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  5. Figure 1. Rapidly wilting black walnut in the final stage of thousand cankers

    E-print Network

    been noted in some Front Range communities in Colorado since 2001 and the twig beetle has been gallery. Figure 3. Distribution of the walnut twig beetle. In green are states and the California county 1998. Pest Alert Walnut Twig Beetle and Thousand Cankers Disease of Black Walnut Within the past decade

  6. 7 CFR 301.75-1 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...plant disease caused by strains of the bacterium Xanthomonas axonopodis pv. citri...that may have been contaminated with bacteria that cause citrus canker. Grove...fruit variety. Infected. Containing bacteria that cause citrus canker....

  7. 7 CFR 301.75-1 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...plant disease caused by strains of the bacterium Xanthomonas axonopodis pv. citri...that may have been contaminated with bacteria that cause citrus canker. Grove...fruit variety. Infected. Containing bacteria that cause citrus canker....

  8. 78 FR 29049 - Streptomycin; Pesticide Tolerances for Emergency Exemptions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-17

    ...aminoglycoside class and is produced by the bacteria streptomyces. The active pesticide...citrus canker, a disease caused by the bacteria Xanthomonas citri. Citrus canker...of antibiotic resistance in pathogenic bacteria, in consideration of factors...

  9. 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...

  10. 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...

  11. CITRUS INDUSTRY October 2011 lorida has the second largest

    E-print Network

    Watson, Craig A.

    CITRUS INDUSTRY · October 2011 F lorida has the second largest orange industry in the world after and now, citrus greening disease, also known as huanglongbing (HLB) or yellow shoot disease in Chinese. There are many parallels and inter- actions between the citrus industries of Florida and Brazil, and the short

  12. Association of Nematodes and Dogwood Cankers

    PubMed Central

    Self, Louann H.; Bernard, Ernest C.

    1994-01-01

    Dogwood canker is a serious production problem of unknown etiology. From May 1985 through April 1989, cankers from 290 flowering dogwood trees in 15 separate nurseries were sampled for nematodes. Seventy-three percent (213) of the cankers contained nematodes. Panagrolaimus rigidus (Schneider) Thorne (115/290) and Aphelenchoides spp. (91/290) were the most frequently collected taxa. Panagrolaimus rigidus was reared on 2% water agar with unidentified bacteria as the food source. Aphelenchoides spp. were reared in antibiotic-amended agar culture with the fungus Glomerella cingulata (Stoneman) Spauld. &Schrenk as a food source. Repeated attempts to culture Aphelenchoides spp. on dogwood callus tissue were unsuccessful. Artificially created stem wounds inoculated with combinations of Aphelenchoides spp. and P. rigidus callused completely in 60 days with no indication of canker development. Very low numbers of nematodes were recovered from inoculated trees, but P. rigidus and one Aphelenchoides sp. were efficient dispersers and occurred in treatments other than those in which they were inoculated. PMID:19279869

  13. Detection of citrus huanglongbing-associated 'Candidatus Liberibacter asiaticus' in citrus and Diaphorina citri in Pakistan, seasonal variability, and implications for disease management.

    PubMed

    Razi, Muhammad F; Keremane, Manjunath L; Ramadugu, Chandrika; Roose, Mikeal; Khan, Iqrar A; Lee, Richard F

    2014-03-01

    We report the detection of the huanglongbing (HLB)-associated bacterium 'Candidatus Liberibacter asiaticus' from both plants and insects in Pakistan and the seasonal variability in the numbers of 'Ca. L. asiaticus'-positive psyllid vector, Diaphorina citri. Our studies showed that 'Ca. L. asiaticus' was detectable from trees in areas with maximum temperatures reaching nearly 50°C (average maximum of 42°C). However, the bacterium was present at very low levels in psyllids both in summer (June to August) and autumn (September to November) in contrast to reports from Florida, where the bacterium was detectable at very high levels during October to November. We hypothesize that hot summer temperatures in Pakistan may interfere with acquisition and replication of 'Ca. L. asiaticus' in psyllids and may lead to dead or non transmissible 'Ca. L. asiaticus' in plants. Psyllid counts were very low in both summer and winter, showed a population peak ('Ca. L. asiaticus'-positive vectors) in spring, and showed a larger peak ('Ca. L. asiaticus'-free psyllids) in autumn. Natural thermotherapy during hot summers and a low vector population during environmental extremes may have played a major role in long-term survival of the citrus industry in Pakistan. These results may be useful in developing management strategies for U.S. citrus industries in Texas and California. PMID:24134720

  14. EVALUATION OF DNA AMPLIFICATION METHODS FOR IMPROVED DETECTION OF CANDIDATUS LIBERIBACTER SPECIES ASSOCIATED WITH CITRUS HUANGLONGBING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB), also known as citrus greening or citrus yellow shoot, is considered the most serious disease of citrus worldwide. The disease has Asian, African and American forms caused by Candidatus Liberibacter asiaticus, Ca. L. africanus and Ca. L. americanus, respectively, which can...

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

    PubMed

    Wenneker, M; Janse, J D; De Bruine, J A

    2011-01-01

    In the Netherlands, bacterial canker in plum trees (Prunus domestica) is a serious and recent problem in plum production. It is caused by Pseudomonas syringae pathovars syringae and morsprunorum. The trunks of the affected plum trees are girdled by bacterial cankers resulting in sudden death of infected trees in 3-4 years after planting. Disease incidences can be very high, and sometimes complete orchards have to be removed. Recently, plum cultivation in the Netherlands has changed from a relatively extensive into an intensive cultivation. However, due to the risks of losses of trees due to bacterial canker, growers are reluctant to plant new plum orchards. In general nurseries and fruit growers are not familiar with bacterial diseases and lack knowledge in order to prevent infections. Therefore, control strategies to manage plum decline have to be developed. PMID:22702175

  16. 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.

  17. Characterization of a proposed dichorhavirus associated with the citrus leprosis disease and analysis of the host response.

    PubMed

    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

    2014-07-01

    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

  18. 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

  19. 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.

  20. 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.

  1. 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...

  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. Regeneration and characterization of somatic hybrid plants of Citrus sinensis (sweet orange) and Citrus micrantha , a progenitor species of lime

    Microsoft Academic Search

    Iqrar A. Khan; Jude W. Grosser

    2004-01-01

    Most commercial citrus fruit species and cultivars are inter- and intra-specific hybrids. Conventional hybridization in citrus is largely handicapped by apomixis and long juvenility. As an alternative, somatic hybridization via protoplast fusion has been employed to create novel citrus germplasm. Witches' broom disease of lime (WBDL) emerged in Oman during the 1970s, which has been spreading to the neighboring countries.

  4. PURIFICATION OF VIRUS-LIKE PARTICLES FROM CITRUS CHLOROTIC DWARF INFECTED CITRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus chlorotic dwarf (CCD) is a new disease of citrus having been found in Turkey in the mid 1980s. Disease symptoms in the field consist of chlorotic leaf patterns, crinkling, leaf distortion, shoot malformation and stunting in young trees. CCD is vectored by the bayberry whitefly and is graft ...

  5. ASIAN CITRUS PSYLLID AND CITRUS GREENING - A CLOSER LOOK AT THE VECTOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae), was first found in Florida during June 1998 and is now widespread throughout much of the state. This invasive psyllid vectors the bacterium responsible for huanglongbing (HLB) (greening disease), a serious citrus disease. HL...

  6. The Asian citrus psyllid and citrus greening - a closer look at the vector

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae), was first found in Florida during June 1998 and is now widespread throughout much of the state. This invasive psyllid vectors the bacterium responsible for huanglongbing (HLB) (greening disease), a serious citrus disease. HL...

  7. 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...

  8. 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...

  9. Transgenic expression in citrus of single-chain antibody fragments specific to Citrus tristeza virus confers virus resistance

    Microsoft Academic Search

    Magdalena Cervera; Olga Esteban; Maite Gil; M. Teresa Gorris; M. Carmen Martínez; Leandro Peña; Mariano Cambra

    2010-01-01

    Citrus tristeza virus (CTV) causes one of the most destructive viral diseases of citrus worldwide. Generation of resistant citrus genotypes through\\u000a genetic engineering could be a good alternative to control CTV. To study whether production of single-chain variable fragment\\u000a (scFv) antibodies in citrus could interfere and immunomodulate CTV infection, transgenic Mexican lime plants expressing two\\u000a different scFv constructs, separately and

  10. Effect of plant growth promoting rhizobacteria on bacterial canker of tomato

    Microsoft Academic Search

    N Girish; S Umesha

    2005-01-01

    Use of plant growth promoting rhizobacteria in managing bacterial canker disease of tomato was studied in the present work. Tomato seeds were treated with PGPR strains viz., Bacillus pumilus INR7, Bacillus pumilus SE34, Bacillus pumilus T4, Bacillus subtilis GBO3, Bacillus amyloliquefaciens IN937a and Brevibacillus brevis IPC11 were subjected for seed germination and seedling vigor. Among the PGPR strains tested, only

  11. Effect of alternative strategies for the disinfection of tomato seed infected with bacterial canker ( Clavibacter michiganensis subsp. michiganensis)

    Microsoft Academic Search

    A.-M. Kasselaki; D. Goumas; L. Tamm; J. Fuchs; J. Cooper; C. Leifert

    2011-01-01

    Currently there is a lack of effective seed treatments for bacterial pathogens, with Cu-based compounds (the only chemical treatments permitted under organic farming standards) only providing partial control. The aim of this study was to quantify the effect of alternative treatments for the control of bacterial canker (Clavibacter michiganensis subsp. michiganensis), a major seed-borne bacterial disease in tomato. Treatments assessed

  12. Behcet's Disease

    MedlinePLUS

    ... of Behcet's disease include recurrent ulcers in the mouth (resembling canker sores) and on the genitals, and eye inflammation. The disorder may also cause various types of skin lesions, arthritis, bowel inflammation, meningitis (inflammation of the membranes ...

  13. Cloning and characterization of receptor kinase class disease resistance gene candidates in Citrus

    Microsoft Academic Search

    Z. Deng; F. G. Gmitter

    2003-01-01

    The rice gene Xa21 represents a unique class of plant disease resistance ( R) genes with distinct protein structure and broad-spectrum specificity; few sequences or genes of this class have been cloned and characterized in other plant species. Degenerate primers were designed from the conserved motifs in the kinase domains of Xa21 and tomato Pto, and used in PCR amplification

  14. DISEASE DEVELOPMENT AND SYMPTOM EXPRESSION OF XANTHOMONAS AXONOPODIS PV. CITRI IN VARIOUS CITRUS PLANT TISSUES.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experimental inoculations of Xanthomonas axonopodis pv. citri (Xac) in different tissues of Tahiti lime and Pineapple sweet orange were conducted monthly under natural conditions in Réunion Island. The interactions between a set of environmental and epidemic variables associated with disease express...

  15. TPCP: Cryphonectria canker of Eucalyptus CRYPHONECTRIA CANKER OF

    E-print Network

    in various parts of the world such as Brazil and India. The disease was discovered in South Africa in 1988 and has already resulted in the elimination of a number of valuable Eucalyptus clones. Cracked tree crown of the world such as Brazil. Sexual spores of Cryphonectria cubensis. MANAGEMENT STRATEGIES The most effective

  16. Effect of Liberibacter infection (Huanglongbing or "greening" disease) of citrus on orange juice flavor quality by sensory evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There have been some anecdotal reports that Liberibacter asiaticus [(+) Las] infection of citrus trees, recently introduced in Florida, imparts off flavor to orange juice. It is of interest to the industry to know how much Liberibacter infection affects juice quality with respect to variety, maturit...

  17. 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 ...

  18. University of Florida Citrus Research and Education Center

    NSDL National Science Digital Library

    Oranges and other citrus plants have been grown in Florida for well over a century, and there has always been a vital relationship between the universities in the state and the citrus industry. The University of Florida Citrus Research and Education Center (CREC) helps foster these valuable relationships, and they have a facility in Lake Alfred, Florida that includes 600 acres of groves, greenhouses, a fresh fruit packinghouse, and more than 40 laboratories. On their website, visitors can learn about their research into hurricane recovery, advanced citrus production, and plant cell physiology in the "Research" section. Over in the "Extension" area, visitors can learn about the diseases the affect citrus crops, read their free "Citrus Pest Management Guide", and also learn about various pesticides. The site also includes links for the media, along with their in-house "Citrus Leaves" newsletter.

  19. Chemical compounds effective against the citrus huanglongbing bacterium 'Candidatus Liberibacter asiaticus' in planta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) is one of the most destructive diseases of citrus worldwide, and is threatening the survival of the Floridian citrus industry. Currently, there is no established cure for this century-old and emerging disease. The new antibiotic combination of penicillin and streptomycin (...

  20. Detection of Citrus Huanglongbing by Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR) Spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus Huanglongbing (HLB, also known as citrus greening disease) was discovered in Florida in 2005 and is spreading rapidly amongst the citrus growing regions of the state. Detection via visual symptoms of the disease is not a long term viable option. New techniques are being developed to test fo...

  1. First Report of Dodder Transmission of Huanglongbing from Naturally Infected Murraya paniculata to Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) or “greening” disease of citrus is caused by phloem-limited, uncultured bacteria in the genus “Candidatus Liberibacter”. HLB is one of the most destructive diseases of citrus worldwide and is considered so dangerous to a U.S. citrus production that the USDA has listed “Ca. Liberi...

  2. Characterization of an ATP/ADP translocase in the citrus huanglongbing bacterium, Candidatus Liberibacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB), a disease currently threatening the citrus industry worldwide, has been associated with three different species of Alphaproteobacteria known as Candidatus Liberibacter. A complete genome sequence was recently obtained via metagenomics for Ca. L. asiaticus (Las), the prom...

  3. Young citrus leaves decrease dispersal distance of Diaphorina citri Kuwayama (Hemiptera: Liviidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To manage citrus Huanglongbing, understanding factors that affect dispersal behavior of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is required to answer questions related to disease epidemiology and to improve management tactics. Currently, little is known about cues medi...

  4. Sequence analysis of three citrus viroids infecting a single Tunisian citrus tree (Citrus, reticulata, Clementine)

    E-print Network

    Perreault, Jean-Pierre

    Sequence analysis of three citrus viroids infecting a single Tunisian citrus tree (Citrus agricole, Ministère de l'Agriculture. Abstract We report the nucleotide sequences of three citrus viroids belonging to three different genera: Citrus exocortis viroid (CEVd), Hop stunt viroid (HSVd) and Citrus

  5. 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.

  6. Establishment of Asian citrus psllid (Diaphorina citri) primary cultures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new cell line was developed from the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae), as a novel approach to culture the bacteria associated with huanglongbing disease (HLB), also known as citrus greening disease. Methods to culture the phloem-inhabiting bacterium Candidatus L...

  7. Lack of Evidence of Transmission of 'Candidatus' Liberibacter Asiaticus Through Citrus Seed Taken From Affected Fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing disease, putatively caused by the associated bacterium Ca. Liberibacter asiaticus is the greatest threat to the world citrus industry today. The bacterium is spread locally and regionally by the citrus psyllid, Diaphorina citri Kuwayama, and can also be disseminated by grafting...

  8. SPATIAL-TEMPORAL DYNAMICS OF CITRUS VARIEGATED CHLOROSIS IN SAO PAULO STATE, BRAZIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus variegated chlorosis (CVC) is one of the most important citrus diseases in Brazil. It is caused by Xylella fastidiosa, a xylem-limited bacterium transmitted by sharpshooter leafhoppers (cicadellids). CVC is widespread in most brazilian citrus areas but incidence and severity can be quite diff...

  9. 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...

  10. Complete Genome sequence of citrus huanglongbing bacterium, ‘Candidatus Liberibacter asiaticus’ obtained through metagenomics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) is the most destructive disease of citrus worldwide. It is spread by the citrus psyllids (Diaphorina citri and Trioza erytreae), and is associated with low-titer, phloem-limited infections by any of the three uncultured species of a-Proteobacteria: 'Candidatus Liberibact...

  11. Citrus Stubborn Severity is Associated with Spiroplasma Citri Titer but Not with Bacterial Genotype.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of citrus stubborn disease (CSD), caused by Spiroplasma citri, on citrus production is associated with symptom severity of infected citrus trees. To assess whether symptom severity was associated with spiroplasma titer in the plant, 58 S. citri strains were cultivated from severely and mi...

  12. Citrus Orchard Management in Texas.

    E-print Network

    Hancock, Bluefford G.

    1962-01-01

    to observe evidence of damage b\\ pev, and diseases. Then take appropriate action. Young Citrus Orchard Cultivation Cultivation or tillage of the orchard soil is not essential. However, weeds interfere with certain grove operations and they also use watcr... is a popular ing machine. ' may be obtained by disking the soil, chop- lowing or shredding. metliotl ant1 gr; equipp~ :ing is the cheapest and most efficient of destroying a heavy growth of weeds Isses. The tandem disk harrow should be ed so...

  13. Morphology, ultrastructure, and bacteriophage infection of the helical mycoplasma-like organism (Spiroplasma citri gen. nov., sp. nov.) cultured from "stubborn" disease of citrus.

    PubMed

    Cole, R M; Tully, J G; Popkin, T J; Bové, J M

    1973-07-01

    The mycoplasma-like organism Spiroplasma citri gen. nov., sp. nov., isolated from citrus infected with "Stubborn" disease and carried in serial cultures in several media, was examined by dark-field microscopy and electron microscopy of negatively-stained and shadowed preparations and of sections. It grows as motile, helical filaments in liquid, but as nonmotile, nonhelical filaments and round bodies in agar cultures. Helicity and motility are lost in old broth cultures and upon addition of a variety of negative stains, fixatives, and other solutions. No organelles accounting for motility are present, but a layer of surface projections is present on the surface of the single, bounding membrane. The mycoplasma produces a tailed, type B bacteriophage which appear to attach to the outer layer. Helical filaments are preserved in ammonium molybdate, but not in sodium phosphotungstate, and by fixation in Formalin or glutaraldehyde made up in medium, but not by osmium nor by glutaraldehyde in cacodylate buffer. This mycoplasma appears similar to the noncultured helical microorganism in corn stunt-diseased tissues and is probably a representative of a new group of mycoplasmas which are in possession of surface projections, rotary motility, and bacteriophage infection. PMID:4123916

  14. Behavioral, ultrastructural and chemical studies on the honeydew and waxy secretions by nymphs and adults of the Asian citrus psyllid Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera, Psyllidae) is the primary vector of citrus huanglongbing (citrus greening), the most serious disease of citrus worldwide. Behavioral, ultrastructural and chemical studies on ACP, its honeydew and waxy secretions suggested some mechanisms b...

  15. FIRST REPORT OF CITRUS BLIGHT IN COSTA RICA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus blight (CB), causing a chronic decline of citrus, has been an important disease in Florida for over 100 years. CB was first reported in Brazil in the 1980s and is now responsible for the removal of nearly 10% of the trees from production annually. No causal agent has been identified, but CB h...

  16. Interactions of citrus variegated chlorosis (CVC) with endophytic bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus variegated chlorosis (CVC), is a disease of sweet orange [Citrus sinensis (L.)], is caused by Xylella fastidiosa subsp. pauca, a phytopathogenic bacterium that has been shown to infect all sweet orange cultivars. Xylella fastidiosa is a fastidious Gram negative, xylem-limited bacterium which ...

  17. Update on the USDA, ARS Citrus Scion Improvement Project

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A citrus breeding program has been conducted by the USDA in Florida since 1893 when W.T. Swingle made his first crosses at the USDA Subtropical Laboratory in Eustis, FL. The initial emphasis was to develop disease resistant cultivars. A second objective was to develop citrus fruit that were easy to...

  18. Associated bacteria of Asian citrus psyllid (Hemiptera: Psyllidae: Diaphorina citri)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a genetics approach two new bacterial species were identified from the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). Psyllids are economically important in the U.S. as vectors of the pathogen associated with citrus greening disease (Huanglongbing). Huanglongbing is on...

  19. Florida actions toward HLB control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Florida citrus industry has suffered major disease setbacks in 2005-2006. The fall 2005 discovery of huanglongbing (HLB) in Florida was just a few months before the decision to halt the citrus canker eradication program because of the predicted massive spread of citrus canker over much of south...

  20. Effects on Asian Citrus Psyllid (Diaphorina citri Kuwayama) feeding behavior of fenpropathrin and chlorpyrifos within 24 hours of application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), also known as citrus greening disease, is one of the most destructive diseases affecting citrus production. The phloem-limited bacterium associated with HLB is transmitted by the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). One component of HLB managem...

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

    PubMed

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

    2014-10-01

    The population phenology of Asian citrus psyllid, Diaphorina citri Kuwayama, was monitored weekly for 110 wk on two species of Citrus, kinnow mandarin and sweet orange, at two different research sites in Faisalabad, Punjab Pakistan. Citrus flush growth patterns were monitored and natural enemy surveys were conducted weekly. Flush patterns were similar for kinnow and sweet orange. However, flush on sweet orange was consistently more heavily infested with Asian citrus psyllid than kinnow flush; densities of Asian citrus psyllid eggs, nymphs, and adults were higher on sweet orange when compared with kinnow. When measured in terms of mean cumulative insect or Asian citrus psyllid days, eggs, nymphs, and adults were significantly higher on sweet orange than kinnow. Two parasitoids were recorded attacking Asian citrus psyllid nymphs, Tamarixia radiata (Waterston) and Diaphorencyrtus aligarhensis (Shafee, Alam and Agarwal). The dominant parasitoid species attacking Asian citrus psyllid nymphs on kinnow and sweet orange was T. radiata, with parasitism averaging 26%. D. aligarhensis parasitism averaged 17%. Generalist predators such as coccinellids and chrysopids were collected infrequently and were likely not important natural enemies at these study sites. Immature spiders, in particular, salticids and yellow sac spiders, were common and may be important predators of all Asian citrus psyllid life stages. Low year round Asian citrus psyllid densities on kinnow and possibly high summer temperatures, may, in part, contribute to the success of this cultivar in Punjab where Candidatus Liberibacter asiaticus, the putative causative agent of huanglongbing, a debilitating citrus disease, is widespread and vectored by Asian citrus psyllid. PMID:25198345

  2. Floral nectar chemical composition of floral nectar in conventional and transgenic sweet orange, Citrus sinensis (L.) Osbeck, expressing an antibacterial peptide

    Microsoft Academic Search

    V. Sala Junior; V. R. Celloto; L. G. E. Vieira; J. E. Gonçalves; R. A. C. Gonçalves; A. J. B. de Oliveira

    2008-01-01

    Floral nectar chemical composition of conventional and transgenic sweet orange trees expressing the antibacterial peptide\\u000a sarcotoxin IA (Stx IA), which has been shown to efficiently inhibit in vitro growth of the bacteria responsible for citrus\\u000a canker (Xanthomonas axonopodis pv. citri), is reported. The nectar contents of primary metabolites (sugars, amino acids, proteins, triacylglycerides) and\\u000a of the secondary metabolites (total purine

  3. The Eucalyptus canker pathogen Chrysoporthe cubensis discovered in eastern Australia

    E-print Network

    The Eucalyptus canker pathogen Chrysoporthe cubensis discovered in eastern Australia Geoffrey S Pathology Centre, The University of Queensland/Agri-Science Queensland, Qld 4068, Australia. B Forestry these trees are planted as non-natives. Although the majority of Eucalyptus spp. are native to Australia, Chr

  4. Assessing quantitative resistance against Leptosphaeria maculans (phoma stem canker) in Brassica napus (oilseed rape) in young plants.

    PubMed

    Huang, Yong-Ju; Qi, Aiming; King, Graham J; Fitt, Bruce D L

    2014-01-01

    Quantitative resistance against Leptosphaeria maculans in Brassica napus is difficult to assess in young plants due to the long period of symptomless growth of the pathogen from the appearance of leaf lesions to the appearance of canker symptoms on the stem. By using doubled haploid (DH) lines A30 (susceptible) and C119 (with quantitative resistance), quantitative resistance against L. maculans was assessed in young plants in controlled environments at two stages: stage 1, growth of the pathogen along leaf veins/petioles towards the stem by leaf lamina inoculation; stage 2, growth in stem tissues to produce stem canker symptoms by leaf petiole inoculation. Two types of inoculum (ascospores; conidia) and three assessment methods (extent of visible necrosis; symptomless pathogen growth visualised using the GFP reporter gene; amount of pathogen DNA quantified by PCR) were used. In stage 1 assessments, significant differences were observed between lines A30 and C119 in area of leaf lesions, distance grown along veins/petioles assessed by visible necrosis or by viewing GFP and amount of L. maculans DNA in leaf petioles. In stage 2 assessments, significant differences were observed between lines A30 and C119 in severity of stem canker and amount of L. maculans DNA in stem tissues. GFP-labelled L. maculans spread more quickly from the stem cortex to the stem pith in A30 than in C119. Stem canker symptoms were produced more rapidly by using ascospore inoculum than by using conidial inoculum. These results suggest that quantitative resistance against L. maculans in B. napus can be assessed in young plants in controlled conditions. Development of methods to phenotype quantitative resistance against plant pathogens in young plants in controlled environments will help identification of stable quantitative resistance for control of crop diseases. PMID:24454767

  5. Assessing Quantitative Resistance against Leptosphaeria maculans (Phoma Stem Canker) in Brassica napus (Oilseed Rape) in Young Plants

    PubMed Central

    Huang, Yong-Ju; Qi, Aiming; King, Graham J.; Fitt, Bruce D. L.

    2014-01-01

    Quantitative resistance against Leptosphaeria maculans in Brassica napus is difficult to assess in young plants due to the long period of symptomless growth of the pathogen from the appearance of leaf lesions to the appearance of canker symptoms on the stem. By using doubled haploid (DH) lines A30 (susceptible) and C119 (with quantitative resistance), quantitative resistance against L. maculans was assessed in young plants in controlled environments at two stages: stage 1, growth of the pathogen along leaf veins/petioles towards the stem by leaf lamina inoculation; stage 2, growth in stem tissues to produce stem canker symptoms by leaf petiole inoculation. Two types of inoculum (ascospores; conidia) and three assessment methods (extent of visible necrosis; symptomless pathogen growth visualised using the GFP reporter gene; amount of pathogen DNA quantified by PCR) were used. In stage 1 assessments, significant differences were observed between lines A30 and C119 in area of leaf lesions, distance grown along veins/petioles assessed by visible necrosis or by viewing GFP and amount of L. maculans DNA in leaf petioles. In stage 2 assessments, significant differences were observed between lines A30 and C119 in severity of stem canker and amount of L. maculans DNA in stem tissues. GFP-labelled L. maculans spread more quickly from the stem cortex to the stem pith in A30 than in C119. Stem canker symptoms were produced more rapidly by using ascospore inoculum than by using conidial inoculum. These results suggest that quantitative resistance against L. maculans in B. napus can be assessed in young plants in controlled conditions. Development of methods to phenotype quantitative resistance against plant pathogens in young plants in controlled environments will help identification of stable quantitative resistance for control of crop diseases. PMID:24454767

  6. Reclassification of the butternut canker fungus, Sirococcus clavigignenti-juglandacearum, into the genus Ophiognomonia.

    PubMed

    Broders, K D; Boland, G J

    2011-01-01

    Sirococcus clavigignenti-juglandacearum (Sc-j), which causes a canker disease on butternut, is largely responsible for the decline of this tree in the United States and Canada. The original description of the species was based on anamorphic characters because the teleomorph is unknown. Recent phylogenetic investigations have found that Sc-j is not a member of the genus Sirococcus, and accurate taxonomic classification is required. The objective of this study is to use sequence data to determine the phylogenetic placement of Sc-j within the Gnomoniaceae, Diaporthales. Isolates were recovered from infected Juglans ailantifolia var. cordiformis (heartnut), Juglans cinerea (butternut), and Juglans nigra (black walnut) in Ontario and the eastern United States. The genes coding for ?-tubulin, actin, calmodulin, internal transcribed spacers 1 and 2, and the translation elongation factor 1-alpha from 28 isolates of Sc-j and representatives of the major lineages within the Gnomoniaceae were evaluated. There was no difference in the sequences of the five genes among the isolates of Sc-j studied, indicating a recent introduction followed by asexual reproduction and spread via conidia. The phylogenetic analyses demonstrate this fungus does not belong to the genus Sirococcus, and provides strong support (99% MP and 100% NJ bootstrap values, and 100% Bayesian posterior probabilities) for its inclusion in the genus Ophiognomonia, thereby supporting a reclassification of the butternut canker fungus to Ophiognomonia clavigignenti-juglandacearum. PMID:21215957

  7. Use of a climatic rule and fuzzy sets to model geographic distribution of climatic risk for European canker (Neonectria galligena) of apple.

    PubMed

    Kim, Kwang Soo; Beresford, Robert M

    2012-02-01

    A rule-based model was developed to assess climatic risk of European canker (Neonectria galligena), which is a major disease of apple in some temperate zones. A descriptive rule was derived from published observations on climatic conditions favorable for European canker development. Fuzzy set theory was used to evaluate the descriptive rule quantitatively. The amount and frequency of rainfall and the average number of hours between 11 and 16°C/day were used as input variables whose values were matched with terms in the rule, e.g., 'high' or 'low'. The degree of a term, e.g., the state of being high or low, to a given input value was determined using a membership function that converts an input value to a number between 0 and 1. The rule was evaluated by combining the degree of the terms associated with monthly climate data. Monthly risk index values derived using the rule were combined for pairs of consecutive months over 12 months. The annual risk of European canker development was represented by the maximum risk index value for 2 months combined. The membership function parameters were adjusted iteratively to achieve a specified level of risk at Talca (Chile), Loughgall (Northern Ireland), East Malling (UK), and Sebastopol (USA), where European canker risk was known. The rule-based model was validated with data collected from Canada, Ecuador, Denmark, Germany, Norway, Poland, Sweden, the Netherlands, New Zealand, and the Pacific Northwest (USA), where European canker has been reported to occur. In these validation areas, the model's risk prediction agreed with reports of disease occurrence. The rule-based model also predicted high risk areas more reliably than the climate matching model, CLIMEX, which relies on correlations between the spatial distribution of a species and climatic conditions. The combination of a climatic rule and fuzzy sets could be used for other applications where prediction of the geographic distribution of organisms is required for climatic risk assessment. PMID:21809979

  8. Adaptive Potential of Maritime Pine (Pinus pinaster) Populations to the Emerging Pitch Canker Pathogen, Fusarium circinatum

    PubMed Central

    Elvira-Recuenco, Margarita; Iturritxa, Eugenia; Majada, Juan; Alia, Ricardo; Raposo, Rosa

    2014-01-01

    There is a concern on how emerging pests and diseases will affect the distribution range and adaptability of their host species, especially due to different conditions derived from climate change and growing globalization. Fusarium circinatum, which causes pitch canker disease in Pinus species, is an exotic pathogen of recent introduction in Spain that threatens its maritime pine (P. pinaster) stands. To predict the impact this disease will have on the species, we examine host resistance traits and their genetic architecture. Resistance phenotyping was done in a clonal provenance/progeny trial, using three-year-old cuttings artificially inoculated with the pathogen and maintained under controlled environmental conditions. A total number of 670 ramets were assessed, distributed in 10 populations, with a total of 47 families, 2 to 5 half-sibs per family, and 3–7 ramets per clone. High genetic variation was found at the three hierarchical levels studied: population, family and clone, being both additive and non-additive effects important. Narrow-sense and broad-sense heritability estimates were relatively high, with respective values of 0.43–0.58 and 0.51–0.8, depending on the resistance traits measured (lesion length, lesion length rate, time to wilting, and survival). These values suggest the species' high capacity of evolutionary response to the F. circinatum pathogen. A population originated in Northern Spain was the most resistant, while another from Morocco was the most susceptible. The total number of plants that did not show lesion development or presented a small lesion (length<30 mm) was 224 out of 670, indicating a high proportion of resistant trees in the offspring within the analyzed populations. We found large differences among populations and considerable genetic variation within populations, which should allow, through natural or artificial selection, the successful adaptation of maritime pine to pitch canker disease. PMID:25500822

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

    PubMed

    Elvira-Recuenco, Margarita; Iturritxa, Eugenia; Majada, Juan; Alia, Ricardo; Raposo, Rosa

    2014-01-01

    There is a concern on how emerging pests and diseases will affect the distribution range and adaptability of their host species, especially due to different conditions derived from climate change and growing globalization. Fusarium circinatum, which causes pitch canker disease in Pinus species, is an exotic pathogen of recent introduction in Spain that threatens its maritime pine (P. pinaster) stands. To predict the impact this disease will have on the species, we examine host resistance traits and their genetic architecture. Resistance phenotyping was done in a clonal provenance/progeny trial, using three-year-old cuttings artificially inoculated with the pathogen and maintained under controlled environmental conditions. A total number of 670 ramets were assessed, distributed in 10 populations, with a total of 47 families, 2 to 5 half-sibs per family, and 3-7 ramets per clone. High genetic variation was found at the three hierarchical levels studied: population, family and clone, being both additive and non-additive effects important. Narrow-sense and broad-sense heritability estimates were relatively high, with respective values of 0.43-0.58 and 0.51-0.8, depending on the resistance traits measured (lesion length, lesion length rate, time to wilting, and survival). These values suggest the species' high capacity of evolutionary response to the F. circinatum pathogen. A population originated in Northern Spain was the most resistant, while another from Morocco was the most susceptible. The total number of plants that did not show lesion development or presented a small lesion (length<30 mm) was 224 out of 670, indicating a high proportion of resistant trees in the offspring within the analyzed populations. We found large differences among populations and considerable genetic variation within populations, which should allow, through natural or artificial selection, the successful adaptation of maritime pine to pitch canker disease. PMID:25500822

  10. Delimiting cryptic pathogen species causing apple Valsa canker with multilocus data

    PubMed Central

    Wang, Xuli; Zang, Rui; Yin, Zhiyuan; Kang, Zhensheng; Huang, Lili

    2014-01-01

    Fungal diseases are posing tremendous threats to global economy and food safety. Among them, Valsa canker, caused by fungi of Valsa and their Cytospora anamorphs, has been a serious threat to fruit and forest trees and is one of the most destructive diseases of apple in East Asia, particularly. Accurate and robust delimitation of pathogen species is not only essential for the development of effective disease control programs, but also will advance our understanding of the emergence of plant diseases. However, species delimitation is especially difficult in Valsa because of the high variability of morphological traits and in many cases the lack of the teleomorph. In this study, we delimitated species boundary for pathogens causing apple Valsa canker with a multifaceted approach. Based on three independent loci, the internal transcribed spacer (ITS), ?-tubulin (Btu), and translation elongation factor-1 alpha (EF1?), we inferred gene trees with both maximum likelihood and Bayesian methods, estimated species tree with Bayesian multispecies coalescent approaches, and validated species tree with Bayesian species delimitation. Through divergence time estimation and ancestral host reconstruction, we tested the possible underlying mechanisms for fungal speciation and host-range change. Our results proved that two varieties of the former morphological species V. mali represented two distinct species, V. mali and V. pyri, which diverged about 5 million years ago, much later than the divergence of their preferred hosts, excluding a scenario of fungi–host co-speciation. The marked different thermal preferences and contrasting pathogenicity in cross-inoculation suggest ecological divergences between the two species. Apple was the most likely ancestral host for both V. mali and V. pyri. Host-range expansion led to the occurrence of V. pyri on both pear and apple. Our results also represent an example in which ITS data might underestimate species diversity. PMID:24834333

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  12. Development of primers and probes for detection of citrus "Candidatus Liberibacter species" by real-time PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) or citrus greening is the most threatening bacterial disease of Citrus spp. Three uncultured Candidatus Liberibacter spp. are usually detected by conventional PCR or real-time PCR using species specific primers and probes based on the 16S rRNA gene. Recent molecular analy...

  13. Analysis of indigenous members of the citrus-family (Rutacea) for bacteria of the "Candidatus Liberibacter" genus.

    E-print Network

    Analysis of indigenous members of the citrus-family (Rutacea) for bacteria of the "Candidatus on indigenous members of the citrus-family, Rutacea. Bacteria within the genus Liberibacter are plant pathogens on a variety of plant hosts. In South Africa, Ca. L. africanus causes greening disease of citrus and `Ca. L

  14. Detection of Candidatus Liberibacter asiaticus in Diaphorina citri and its importance in the management of Citrus Huanglongbing in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB or citrus greening) is a highly destructive disease that has been spreading in both Florida and Brazil. Its psyllid vector, Diaphorina citri, has spread to Texas and Mexico thus threatening the future of citrus production elsewhere in North America. Even though, sensitive d...

  15. Citrus Huanglongbing: The Pathogen and Its Impact

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The article is a detailed review of the present status of huanglongbing (HLB) in the US and Brazil. HLB is known to be the most severe and destructive of all diseases of citrus greatly affecting yield and quality, and leads to tree death. It also has severe regulatory and quarantine implications a...

  16. 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...

  17. Differences in secondary metabolites in leaves from orange trees (Citrus sinensis L.) affected with greening disease (Huanglongbing) (HLB)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Preliminary analyses by HPLC-MS of methanolic extracts of two sets of orange leaves that are symptomatic of the Greening Disease (HLB) have shown several consistent differences. The main flavonoids in symptomatic and nonsymptomatic leaves were monitored in the HPLC chromatograms at 330 nm, and signi...

  18. ISOLATION OF AN EFFECTIVE PROMOTER FROM CITRUS YELLOW MOSAIC VIRUS FOR EXPRESSION OF DISEASE RESISTANT GENES IN ORNAMENTAL CROPS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial diseases caused by Agrobacterium, Erwinia, Pseudomonas, Xanthomonas and Ralstonia spp. often result in significant loses in the production and quality of ornamental crops, and are very difficult to control. The use of genetically engineered crops offers a novel, cost effective and environ...

  19. The genome of the non-cultured, bacterial-like organism associated with citrus greening disease contains the nus G- rpl KAJL- rpo BC gene cluster and the gene for a bacteriophage type DNA polymerase

    Microsoft Academic Search

    Sandrine Villechanoux; Monique Garnier; Frédéric Laigret; Joël Renaudin; Joseph-Marie Bové

    1993-01-01

    We have recently cloned three DNA fragments (In-2.6, In-1.0, and In-0.6) of the noncultured, bacterial-like organism (BLO) associated with citrus greening disease. Nucleotide sequence determination has shown that fragment In-2.6 is part of therplKAJL-rpoBC gene cluster, a well-known operon in eubacteria. The DNA fragment upstream of and partially overlapping with In-2.6 could be isolated and was shown to be thenusG

  20. A framework to gauge the epidemic potential of plant pathogens in environmental reservoirs: the example of kiwifruit canker.

    PubMed

    Bartoli, Claudia; Lamichhane, Jay Ram; Berge, Odile; Guilbaud, Caroline; Varvaro, Leonardo; Balestra, Giorgio M; Vinatzer, Boris A; Morris, Cindy E

    2015-02-01

    New economically important diseases on crops and forest trees emerge recurrently. An understanding of where new pathogenic lines come from and how they evolve is fundamental for the deployment of accurate surveillance methods. We used kiwifruit bacterial canker as a model to assess the importance of potential reservoirs of new pathogenic lineages. The current kiwifruit canker epidemic is at least the fourth outbreak of the disease on kiwifruit caused by Pseudomonas syringae in the mere 50 years in which this crop has been cultivated worldwide, with each outbreak being caused by different genetic lines of the bacterium. Here, we ask whether strains in natural (non-agricultural) environments could cause future epidemics of canker on kiwifruit. To answer this question, we evaluated the pathogenicity, endophytic colonization capacity and competitiveness on kiwifruit of P.?syringae strains genetically similar to epidemic strains and originally isolated from aquatic and subalpine habitats. All environmental strains possessing an operon involved in the degradation of aromatic compounds via the catechol pathway grew endophytically and caused symptoms in kiwifruit vascular tissue. Environmental and epidemic strains showed a wide host range, revealing their potential as future pathogens of a variety of hosts. Environmental strains co-existed endophytically with CFBP 7286, an epidemic strain, and shared about 20 virulence genes, but were missing six virulence genes found in all epidemic strains. By identifying the specific gene content in genetic backgrounds similar to known epidemic strains, we developed criteria to assess the epidemic potential and to survey for such strains as a means of forecasting and managing disease emergence. PMID:24986268

  1. Screening molecules for control of citrus Huanglongbing (HLB) using an optimized regeneration system for 'Candidatus Liberibacter asiaticus' infected periwinkle (Catharunthus roseus) cuttings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) ( also known as citrus greening) is one of the most destructive diseases of citrus worldwide. The disease is associated with three different species of Candidatus Liberibacter, of which, ‘Ca. L. asiaticus’ (Las) is the most widely-distributed. An improved system using HLB-...

  2. The effect of 'Candidatus Liberibacter asiaticus' infection on the proteomic profiles and nutritional status of pre-symptomatic and symptomatic grapefruit (Citrus paradisi) plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a highly destructive citrus disease which threatens citrus production worldwide. Among three known ‘Candidatus Liberibacter’ species associated with HLB, ‘Ca. Liberibacter asiaticus’ (Las) is the most prevalent. To better understand the physiological and molecular processes in...

  3. Invasive Plants, Species and Conditions Fact Sheets: Cheatgrass Brome, Bamboo Reed, Butternut Canker, Dutch Elm, Chestnut Blight, Asian Cycad Scale, Crazy Ant, Red Fox

    NSDL National Science Digital Library

    This resource from ATEEC provides a number of fact sheets on invasive plants, species and conditions which may be printed out or used as presentation material. The plants, species and conditions described here are cheatgrass brome, bamboo reed, butternut canker, dutch elm disease, chestnut blight, Asian cycad scale, crazy ant and red fox. The lesson plan is available for download as a PDF; users must create a free, quick login with ATEEC to access the materials.

  4. Genome sequence of Candidatus Liberibacter asiaticus, the casual agent of citrus huanglongbing (greening)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide. The disease is associated with three different species of Candidatus Liberibacter: Ca. L. asiaticus (Las), Ca. L. americanus and Ca. L. africanus. We first detected and identified Las bacterium from HLB-infected...

  5. Near-Infrared Spectroscopy for discrimination of huanglongbing-infected citrus leaves from uninfected leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus greening, also called Huanglongbing (HLB) or yellow dragon disease, is one of the more serious diseases of citrus and is a threat to the U.S. industry. An infected tree produces fruit that is unsuitable for sale as fresh fruit or for juice. The only definitive method of diagnosis of trees su...

  6. CITRUS ROOTSTOCKS: THEIR CHARACTERS AND

    E-print Network

    CITRUS ROOTSTOCKS: THEIR CHARACTERS AND REACTIONS (an unpublished manuscript) ca. 1986 By W. P Library, retired Subject matter experts, digital version: Dr. Tracy Kahn, Curator, UC Citrus Variety Collection Dr. Robert Krueger, Curator, USDA-ARS National Clonal Germplasm Repository for Citrus & Dates Toni

  7. Titers of 'Ca. Liberibacter asiaticus' in Murraya paniculata and Murraya-reared Diaphorina citri are much lower than in citrus and citrus-reared psyllids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing, one of the most devastating diseases of citrus, is associated with the bacterium Candidatus Liberibacter asiaticus vectored by the Asian citrus psyllid, Diaphorina citri, in North America. Murraya paniculata is a common ornamental plant that is an alternate host of Ca. L. asiaticus an...

  8. Effect of Cyantraniliprole, a novel insecticide, on the inoculation of Candidatus Liberibacter asiaticus associated with citrus huanglongbing by the Asian citrus psyllid (Hemiptera: Liviidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (Diaphorina citri Kuwayama) is the principal vector of Candidatus Liberibacter asiaticus (LAS) associated with huanglongbing (HLB), the most serious citrus disease worldwide. New research tools and control measures are urgently needed to combat HLB, and protecting newly plan...

  9. Comparison of FTIR spectra between huanglongbing (citrus greening) and other citrus maladies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fourier Transform Infrared Spectroscopy has the ability to quickly identify the presence of specific carbohydrates in plant materials. The presence of the disease Huanglongbing(HLB) in the leaves of infected citrus plants has a distinctive spectrum that can be used to distinguish an infected plant ...

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

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Regulated articles for Asian citrus psyllid and citrus greening. 301.76-2 Section 301.76-2...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  11. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Regulated articles for Asian citrus psyllid and citrus greening. 301.76-2 Section 301.76-2...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  12. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Regulated articles for Asian citrus psyllid and citrus greening. 301.76-2 Section 301.76-2...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  13. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Quarantined areas; citrus greening and Asian citrus psyllid. 301.76-3 Section 301.76-3...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  14. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Quarantined areas; citrus greening and Asian citrus psyllid. 301.76-3 Section 301.76-3...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  15. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Regulated articles for Asian citrus psyllid and citrus greening. 301.76-2 Section 301.76-2...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  16. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Quarantined areas; citrus greening and Asian citrus psyllid. 301.76-3 Section 301.76-3...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  17. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Quarantined areas; citrus greening and Asian citrus psyllid. 301.76-3 Section 301.76-3...DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Greening and Asian Citrus Psyllid §...

  18. Bionomics of Asian citrus psyllid (Hemiptera: Liviidae) associated with orange jasmine hedges in southest central Florida, with special reference to biological control by Tamarixia radiata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is an important pest in Florida because it vectors bacteria responsible for citrus huanglongbing disease. In addition to infesting citrus, orange jasmine (Murraya paniculata) is one of ACP’s favorite host plants and is widely grown as an orn...

  19. 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 ...

  20. MULTIPLEX TAQMAN-BASED PCR FOR SENSITIVE AND ACCURATE QUANTIFICATION OF CITRUS HLB AND CVC PATHOGENS; CANDIDATUS LIBERIBACTER AND XYLELLA FASTIDIOSA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus Huanglongbing (HLB, also known as citrus greening disease) and citrus variegated chlorosis (CVC) are caused by Candidatus Liberibacter (CL) and Xylella fastidiosa (Xf) respectively. Both pathogens were listed as plant bio-threat agents in 2002 US Agricultural Bioterrorism Protection Act. Citr...

  1. 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...

  2. Bionomics of Asian citrus psyllid associated with orange jasmine hedges in Florida, with special reference to biological control by Tamarixia radiata

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP) is an important invasive citrus pest because it vectors a bacterium responsible for a devastating disease of citrus known as huanglongbing. Orange jasmine (Murraya paniculata) is a favored alternate ACP host plant and is widely grown as an ornamental plant in urban ar...

  3. 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 ...

  4. Cellular automata model for citrus variegated chlorosis

    NASA Astrophysics Data System (ADS)

    Martins, M. L.; Ceotto, G.; Alves, S. G.; Bufon, C. C. B.; Silva, J. M.; Laranjeira, F. F.

    2000-11-01

    A cellular automata model is proposed to analyze the progress of citrus variegated chlorosis epidemics in São Paulo orange plantations. In this model epidemiological and environmental features, such as motility of sharpshooter vectors that perform Lévy flights, level of plant hydric and nutritional stress, and seasonal climatic effects, are included. The observed epidemic data were quantitatively reproduced by the proposed model on varying the parameters controlling vector motility, plant stress, and initial population of diseased plants.

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

    Microsoft Academic Search

    Márcia R Soares; Agda P Facincani; Rafael M Ferreira; Leandro M Moreira; Julio CF de Oliveira; Jesus A Ferro; Rogério Meneghini; Fábio C Gozzo

    2010-01-01

    BACKGROUND: Citrus canker is a disease caused by Xantomonas citri subsp.citri (Xac), and has emerged as one of the major threats to the worldwide citrus crop because it affects all commercial citrus varieties, decreases the production and quality of the fruits and can spread rapidly in citrus growing areas. In this work, the first proteome of Xac was analyzed using

  6. Modeling huanglongbing transmission within a citrus tree

    PubMed Central

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

    2012-01-01

    The citrus disease huanglongbing (HLB), associated with an uncultured bacterial pathogen, is threatening the citrus industry worldwide. A mathematical model of the transmission of HLB between its psyllid vector and citrus host has been developed to characterize the dynamics of the vector and disease development, focusing on the spread of the pathogen from flush to flush (a newly developing cluster of very young leaves on the expanding terminal end of a shoot) within a tree. This approach differs from that of prior models for vector-transmitted plant diseases where the entire plant is the unit of analysis. Dynamics of vector and host populations are simulated realistically as the flush population approaches complete infection. Model analysis indicates that vector activity is essential for initial infection but is not necessary for continued infection because infection can occur from flush to flush through internal movement in the tree. Flush production, within-tree spread, and latent period are the most important parameters influencing HLB development. The model shows that the effect of spraying of psyllids depends on time of initial spraying, frequency, and efficacy of the insecticides. Similarly, effects of removal of symptomatic flush depend on the frequency of removal and the time of initiation of this practice since the start of the epidemic. Within-tree resistance to spread, possibly affected by inherent or induced resistance, is a major factor affecting epidemic development, supporting the notion that alternate routes of transmission besides that by the vector can be important for epidemic development. PMID:22783015

  7. Entomopathogenic fungi infecting the Asian citrus psyllid, Diaphorina citri (Homoptera: Psyllidae), in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri is an invasive pest that vectors citrus greening disease. In 2005-2006 mycosed psyllids displaying two phenotypes were collected in central Florida. The major pathogen, identified by morphological and genetic analyses, was a novel isolate related to Hirsute...

  8. Distribution and Management of Citrus in California: Implications for Management of Glassy-winged Sharpshooter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The epidemiology of Pierce’s disease of grape in California has changed over the last 10 years due to the introduction of an exotic vector, Homalodisca vitripennis (Germar). Although this insect is highly polyphagous, citrus is considered a preferred host of H. vitripennis and proximity to citrus h...

  9. Imazil residue loading and green mould control in south african citrus pack-houses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Imazalil (IMZ) is commonly applied in South African citrus pack-houses for the control of green mould, caused by Penicillium digitatum, yet the disease still causes significant postharvest losses. Maximum residue limit (MRL) for IMZ on citrus fruit is 5 µg.g-1, whereas 2-3 µg.g-1 is regarded as a b...

  10. Effects of soil-applied imidacloprid on Asian citrus psyllid (Hemiptera: Psyllidae) feeding behavior

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama is one of the most important pests of citrus due to its status as a vector of Candidatus Liberibacter asiaticus, the bacterium associated with huanglongbing (HLB) disease. The use of insecticides for vector control is the primary method of managing...

  11. Evaluation of Quantitative Real-Time PCR Assays for Detection of Citrus Greening

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB), or citrus greening, is a serious and industry-limiting disease. Preliminary diagnoses can be made through visual symptoms, and greater certainty can be achieved through quantitative real-time PCR (qPCR). Several qPCR procedures are available including those by designed by...

  12. Synthetic substrate-borne vibrational signals that elicit Asian citrus psyllid communicatory and search responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian Citrus Psyllid (ACP), Diaphorina citri Kuwayama, vectors a harmful bacterium, Candidatus Liberibacter asiaticus, that causes huanglongbing, an economically devastating disease of citrus. Adult male and female ACP transmit vibratory communication signals over 10-50-cm distances within their...

  13. Analyses of proteomic expression profiles and nutrient status of citrus plants in response to HLB

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a highly devastating citrus disease and represents a major threat to the citrus industries in US. The etiology of HLB worldwide is associated with three insect-transmissible phloem-limited members of the bacterial group ‘Candidatus Liberibacter spp’, prevalently ‘Candidatus Li...

  14. 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...

  15. Cryopreservation of citrus in the USDA-ARS national plant germplasm system collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diverse Citrus germplasm from the USDA-ARS National Plant Germplasm System, University of California Riverside, and the California citrus industry is at risk of being lost as a result of disease infestations and unexpected weather disasters. At the National Center for Genetic Resources Preservation ...

  16. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is the most destructive disease of citrus worldwide. Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the vector of the phloem-inhabiting bacterium, Candidatus Liberibacter asiaticus, which is presumed to cause HLB. Laboratory and field studies were cond...

  18. Acoustic signals in the courtship of male and female Asian citrus psyllids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama, was discovered in Broward County, Florida in 1998, and has since spread through most of the state. It is an important vector of Huanglongbing, an economically devastating disease of citrus; consequently, researchers and regulators are trying to d...

  19. Influence of the Brevipalpus phoenicis endosymbiont Cardinium sp. in the transmission of Citrus leprosis virus.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus leprosis is a viral disease of significant economic and environmental impact in Brazil and some other countries in the Americas. Citrus leprosis virus (CiLV), its causal agent, is transmitted by Brevipalpus phoenicis (Acari: Tenuipalpidae), a polyphagous mite that reproduces through thelytoko...

  20. 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...

  1. Evaluation of management programs for protecting young citrus plantings from huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asiatic huanglongbing (HLB) is a devastating disease of citrus associated in North America with the bacterium ‘Candidatus Liberibacter asiaticus’ (LAS) vectored by the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama. ACP management is considered a vital component of a program aimed at reducing...

  2. 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...

  3. Citrus and salinity

    Microsoft Academic Search

    R Storey; R. R Walker

    1998-01-01

    Citrus is a major horticultural crop worldwide and is relatively salt sensitive. Salt damage usually manifests as leaf burn and defoliation, and is associated with accumulation of toxic levels of Na+ and\\/or Cl? in leaf cells. Factors affecting tree response to salinity are documented, including salinity levels for onset and rate of yield decline in mature trees. The review is

  4. 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

  5. The push-pull strategy for citrus psyllid control.

    PubMed

    Yan, Huaxue; Zeng, Jiwu; Zhong, Guangyan

    2014-09-25

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the only natural vector of Candidatus Liberibacter asiaticus that causes citrus huanglongbing (HLB), a most destructive disease of citrus. Currently, no remedial therapy exists for the disease, and so effective control of ACP is very important in curbing the transmission of the disease. The push-pull strategy should be thoroughly explored as an approach to ACP management. This mini-review summarises the current progress towards more effective repellent and attractant chemicals through investigating known repellent and attractive plants. Interactions between ACP and its host plants are also addressed, with emphasis on the possible involvement of the host biochemicals in attracting the insect. Potential ways to increase the effectiveness of the pull-push strategy are briefly discussed. It is expected that the pull-push strategy will be gradually developed following more extensive research. © 2014 Society of Chemical Industry. PMID:25256398

  6. Establishment of Asian citrus psyllid (Diaphorina citri) primary cultures.

    PubMed

    Marutani-Hert, Mizuri; Hunter, Wayne B; Hall, David G

    2009-01-01

    The Asian citrus psyllid (AsCP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a highly competent vector of the phloem-inhabiting bacterium Candidatus Liberibacter asiaticus associated with the citrus disease huanglongbing (HLB). Commonly referred to as citrus greening disease in the USA, HLB causes reduced fruit yields, quality, and ultimately tree death and is considered the most serious citrus disease. HLB has become a major limiting factor to the production of citrus worldwide. Studies of HLB have been impeded by the fact that C. Liberibacter has not yet been cultured on artificial nutrient media. After being acquired by a psyllid, C. Liberibacter asiaticus is reported to replicate within the psyllid and is retained by the psyllid throughout its life span. We therefore hypothesized that C. Liberibacter asiaticus could be cultured in vitro using psyllid cell cultures as the medium and investigated the establishment of a pure culture for AsCP cells. Several commercially available insect cell culture media along with some media we developed were screened for viability to culture cells from AsCP embryos. Cells from psyllid tissues adhered to the plate and migration was observed within 24 h. Cells were maintained at 20 degrees C. We successfully established primary psyllid cell cultures, referred to as DcHH-1, for D. citri Hert-Hunter-1, with a new media, Hert-Hunter-70. PMID:19440802

  7. Molecular systematics of citrus-associated Alternaria species.

    PubMed

    Peever, T L; Su, G; Carpenter-Boggs, L; Timmer, L W

    2004-01-01

    The causal agents of Alternaria brown spot of tangerines and tangerine hybrids, Alternaria leaf spot of rough lemon and Alternaria black rot of citrus historically have been referred to as Alternaria citri or A. alternata. Ten species of Alternaria recently were described among a set of isolates from leaf lesions on rough lemon (Citrus jambhiri) and tangelo (C. paradisi × C. reticulata), and none of these isolates was considered representative of A. alternata or A. citri. To test the hypothesis that these newly described morphological species are congruent with phylogenetic species, selected Alternaria brown spot and leaf spot isolates, citrus black rot isolates (post-harvest pathogens), isolates associated with healthy citrus tissue and reference species of Alternaria from noncitrus hosts were scored for sequence variation at five genomic regions and used to estimate phylogenies. These data included 432 bp from the 5' end of the mitochondrial ribosomal large subunit (mtLSU), 365 bp from the 5' end of the beta-tubulin gene, 464 bp of an endopolygalacturonase gene (endoPG) and 559 and 571 bp, respectively, of two anonymous genomic regions (OPA1-3 and OPA2-1). The mtLSU and beta-tubulin phylogenies clearly differentiated A. limicola, a large-spored species causing leaf spot of Mexican lime, from the small-spored isolates associated with citrus but were insufficiently variable to resolve evolutionary relationships among the small-spored isolates from citrus and other hosts. Sequence analysis of translation elongation factor alpha, calmodulin, actin, chitin synthase and 1, 3, 8-trihydroxynaphthalene reductase genes similarly failed to uncover significant variation among the small-spored isolates. Phylogenies estimated independently from endoPG, OPA1-3 and OPA2-1 data were congruent, and analysis of the combined data from these regions revealed nine clades, eight of which contained small-spored, citrus-associated isolates. Lineages inferred from analysis of the combined dataset were in general agreement with described morphospecies, however, three clades contained more than one morphological species and one morphospecies (A. citrimacularis) was polyphyletic. Citrus black rot isolates also were found to be members of more than a single lineage. The number of morphospecies associated with citrus exceeded that which could be supported under a phylogenetic species concept, and isolates in only five of nine phylogenetic lineages consistently were correlated with a specific host, disease or ecological niche on citrus. We advocate collapsing all small-spored, citrus-associated isolates of Alternaria into a single phylogenetic species, A. alternata. PMID:21148834

  8. Effective antibiotics against 'Candidatus Liberibacter asiaticus' in HLB-affected citrus plants identified via the graft-based evaluation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB), caused by three species of fastidious, phloem-limited ‘Candidatus Liberibacter’, is one of the most destructive diseases of citrus worldwide. To date, there is no established cure for this century-old and yet, newly emerging disease. As a potential control strategy for ci...

  9. Distribution and quantification of Candidatus Liberibacter americanus, agent of huanglongbing disease of citrus in São Paulo State, Brasil, in leaves of an affected sweet orange tree as determined by PCR.

    PubMed

    Teixeira, Diva C; Saillard, Colette; Couture, Carole; Martins, Elaine C; Wulff, Nelson A; Eveillard-Jagoueix, Sandrine; Yamamoto, Pedro T; Ayres, Antonio J; Bové, Joseph M

    2008-06-01

    Huanglongbing (HLB), an insect-transmitted disease of citrus, known for many years in Asia and Africa, has appeared in the state of São Paulo State (SSP), Brazil, in 2004, and the state of Florida, USA, in 2005. HLB endangers the very existence of citrus, as trees infected with the bacterial pathogen, irrevocably decline. In the absence of curative procedures, control of HLB is difficult and only based on prevention. Even though not available in culture, the HLB bacterium could be shown to be Gram-negative and to represent a new candidate genus, Candidatus Liberibacter, in the alpha subdivision of the Proteobacteria. Three Candidatus (Ca.) L. species occur: Ca. L. africanus in Africa, Ca. L. asiaticus in Asia, SSP, and Florida, and Ca. L. americanus in SSP. The liberibacters occur exclusively in the phloem sieve tubes. On affected trees, HLB symptoms are often seen on certain branches only, suggesting an uneven distribution of the Liberibacter. Occurrence of Ca. L. americanus, the major HLB agent in SSP, has been examined in 822 leaf samples from an affected sweet orange tree by two conventional PCR techniques and a newly developed real time (RTi) PCR, also used for quantification of the Liberibacter in the leaves. Even though RTi-PCR was able to detect as few as 10 liberibacters per gram of leaf tissue (l/g), no liberibacters could be detected in any of the many leaf samples from a symptomless branch, while in blotchy mottle leaves from symptomatic branches of the same tree, the Liberibacter titer reached values as high as 10(7)l/g. These results demonstrate the uneven distribution of the Liberibacter in HLB-affected trees. PMID:18400468

  10. 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…

  11. Antifungal activity of lemon ( Citrus lemon L.), mandarin ( Citrus reticulata L.), grapefruit ( Citrus paradisi L.) and orange ( Citrus sinensis L.) essential oils

    Microsoft Academic Search

    M. Viuda-Martos; Y. Ruiz-Navajas; J. Fernández-López; J. Pérez-Álvarez

    2008-01-01

    The objective of this work was to study the effect of the essential oils of lemon (Citrus lemon L.), mandarin (Citrus reticulata L.), grapefruit (Citrus paradisi L.) and orange (Citrus sinensis L.) on the growth of moulds commonly associated with food spoilage: Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum and Penicillium verrucosum, using the agar dilution method. All the oils showed

  12. Economic & Market Research Florida Citrus Outlook

    E-print Network

    Hill, Jeffrey E.

    Economic & Market Research Florida Citrus Outlook 2012-13 Season Florida Agricultural Commodity & Market Research Florida Department of Citrus #12;Economic & Market Research 2 Florida Citrus Outlook 2012-13 Season Available on-line at: http://www.fdocgrower.com/economics/economic- research/outlook-florida-citrus

  13. 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...

  14. CITRUS LIMONOID BIOAVAILABILITY IN HUMANS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The absorption, metabolism and bioavailability of citrus limonoids in human subjects administered high doses of pure limonin glucoside has been reported. In this chapter, the results from this study are compared to the bioavailability results of other citrus secondary metabolites, and future resear...

  15. Candidatus Liberibacter asiaticus titers in citrus cultivars in the field and in Asian Citrus Psyllid-inoculated greenhouse trees

    E-print Network

    McCollum, Greg; Hilf, Mark; Irey, Mike

    2014-01-01

    citrus cultivars (Citrus sinensis, C. paradisi, ‘Temple’sinensis, C. paradisi, Poncirus trifoliata, and nine citrussinensis. In the orchard, Candidatus Liberibacter asiaticus (CLas) is transmitted to citrus

  16. Optimising and Communicating Options for the Control of Invasive Plant Disease When There Is Epidemiological Uncertainty

    PubMed Central

    Cunniffe, Nik J.; Stutt, Richard O. J. H.; DeSimone, R. Erik; Gottwald, Tim R.; Gilligan, Christopher A.

    2015-01-01

    Although local eradication is routinely attempted following introduction of disease into a new region, failure is commonplace. Epidemiological principles governing the design of successful control are not well-understood. We analyse factors underlying the effectiveness of reactive eradication of localised outbreaks of invading plant disease, using citrus canker in Florida as a case study, although our results are largely generic, and apply to other plant pathogens (as we show via our second case study, citrus greening). We demonstrate how to optimise control via removal of hosts surrounding detected infection (i.e. localised culling) using a spatially-explicit, stochastic epidemiological model. We show how to define optimal culling strategies that take account of stochasticity in disease spread, and how the effectiveness of disease control depends on epidemiological parameters determining pathogen infectivity, symptom emergence and spread, the initial level of infection, and the logistics and implementation of detection and control. We also consider how optimal culling strategies are conditioned on the levels of risk acceptance/aversion of decision makers, and show how to extend the analyses to account for potential larger-scale impacts of a small-scale outbreak. Control of local outbreaks by culling can be very effective, particularly when started quickly, but the optimum strategy and its performance are strongly dependent on epidemiological parameters (particularly those controlling dispersal and the extent of any cryptic infection, i.e. infectious hosts prior to symptoms), the logistics of detection and control, and the level of local and global risk that is deemed to be acceptable. A version of the model we developed to illustrate our methodology and results to an audience of stakeholders, including policy makers, regulators and growers, is available online as an interactive, user-friendly interface at http://www.webidemics.com/. This version of our model allows the complex epidemiological principles that underlie our results to be communicated to a non-specialist audience. PMID:25874622

  17. Optimising and communicating options for the control of invasive plant disease when there is epidemiological uncertainty.

    PubMed

    Cunniffe, Nik J; Stutt, Richard O J H; DeSimone, R Erik; Gottwald, Tim R; Gilligan, Christopher A

    2015-04-01

    Although local eradication is routinely attempted following introduction of disease into a new region, failure is commonplace. Epidemiological principles governing the design of successful control are not well-understood. We analyse factors underlying the effectiveness of reactive eradication of localised outbreaks of invading plant disease, using citrus canker in Florida as a case study, although our results are largely generic, and apply to other plant pathogens (as we show via our second case study, citrus greening). We demonstrate how to optimise control via removal of hosts surrounding detected infection (i.e. localised culling) using a spatially-explicit, stochastic epidemiological model. We show how to define optimal culling strategies that take account of stochasticity in disease spread, and how the effectiveness of disease control depends on epidemiological parameters determining pathogen infectivity, symptom emergence and spread, the initial level of infection, and the logistics and implementation of detection and control. We also consider how optimal culling strategies are conditioned on the levels of risk acceptance/aversion of decision makers, and show how to extend the analyses to account for potential larger-scale impacts of a small-scale outbreak. Control of local outbreaks by culling can be very effective, particularly when started quickly, but the optimum strategy and its performance are strongly dependent on epidemiological parameters (particularly those controlling dispersal and the extent of any cryptic infection, i.e. infectious hosts prior to symptoms), the logistics of detection and control, and the level of local and global risk that is deemed to be acceptable. A version of the model we developed to illustrate our methodology and results to an audience of stakeholders, including policy makers, regulators and growers, is available online as an interactive, user-friendly interface at http://www.webidemics.com/. This version of our model allows the complex epidemiological principles that underlie our results to be communicated to a non-specialist audience. PMID:25874622

  18. 75 FR 17289 - Citrus Seed Imports; Citrus Greening and Citrus Variegated Chlorosis

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-06

    ...greening is not known to exist in Costa Rica and Paraguay, but CVC is. Therefore...that seed of the genus Citrus from Costa Rica and Paraguay is prohibited importation...x) Seed of the genus Citrus from Costa Rica and Paraguay is prohibited...

  19. Citrus tristeza virus-host interactions

    PubMed Central

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

    2013-01-01

    Citrus tristeza virus (CTV) is a phloem-limited virus whose natural host range is restricted to citrus and related species. Although the virus has killed millions of trees, almost destroying whole industries, and continually limits production in many citrus growing areas, most isolates are mild or symptomless in most of their host range. There is little understanding of how the virus causes severe disease in some citrus and none in others. Movement and distribution of CTV differs considerably from that of well-studied viruses of herbaceous plants where movement occurs largely through adjacent cells. In contrast, CTV systemically infects plants mainly by long-distance movement with only limited cell-to-cell movement. The virus is transported through sieve elements and occasionally enters an adjacent companion or phloem parenchyma cell where virus replication occurs. In some plants this is followed by cell-to-cell movement into only a small cluster of adjacent cells, while in others there is no cell-to-cell movement. Different proportions of cells adjacent to sieve elements become infected in different plant species. This appears to be related to how well viral gene products interact with specific hosts. CTV has three genes (p33, p18, and p13) that are not necessary for infection of most of its hosts, but are needed in different combinations for infection of certain citrus species. These genes apparently were acquired by the virus to extend its host range. Some specific viral gene products have been implicated in symptom induction. Remarkably, the deletion of these genes from the virus genome can induce large increases in stem pitting (SP) symptoms. The p23 gene, which is a suppressor of RNA silencing and a regulator of viral RNA synthesis, has been shown to be the cause of seedling yellows (SY) symptoms in sour orange. Most isolates of CTV in nature are populations of different strains of CTV. The next frontier of CTV biology is the understanding how the virus variants in those mixtures interact with each other and cause diseases. PMID:23717303

  20. Use of carnauba based carrier for copper sprays reduces infection by Xanthomonas citri subsp. citri and Diaporthe citri in Florida commercial grapefruit groves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asiatic citrus canker caused by Xanthomonas citri subsp. citri (Xcc), a bacterial disease of citrus, was first documented on Florida citrus in the early 1900’s. At that time the disease was managed, only to return in the 1980’s and 90’s and to finally remain uncontrolled in 2004. Xcc is most active ...

  1. Citrus greening detection using airborne hyperspectral and multispectral imaging techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hyperspectral imaging can provide unique spectral signatures for diseased vegetation. Airborne multispectral and hyperspectral imaging can be used to detect potentially infected trees over a large area for rapid detection of infected zones. This paper proposes a method to detect the citrus greening...

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

    PubMed

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

    2014-10-01

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

  3. REAL-TIME PCR DETECTION AND DEVELOPMENT OF A BIOASSAY FOR THE DEEP BARK CANKER PATHOGEN, BRENNARIA RUBRIFACIENS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deep Bark Canker (DBC), caused by the bacterium Brennaria rubrifaciens afflicts English walnut cultivars and is characterized by late onset of symptoms in trees greater than 15 years old. These symptoms include deep bleeding vertical cankers along the trunk and larger branches that exude a bacteria...

  4. Multispectral sensing of citrus young tree decline

    NASA Technical Reports Server (NTRS)

    Edwards, G. J.; Ducharme, E. P.; Schehl, T.

    1975-01-01

    Computer processing of MSS data to identify and map citrus trees affected by young tree decline is analyzed. The data were obtained at 1500-feet altitude in six discrete spectral bands covering regions from 0.53 to 1.3 millimicrons as well as from instrumental ground truths of tree crowns. Measurable spectral reflectance intensity differences are observed in the leaves of healthy and diseased trees, especially at wavelengths of 500 to 600 nm and 700 to 800 nm. The overall accuracy of the method is found to be 89%.

  5. Distribution and Management of Citrus in California: Implications for Spread and Management of Glassy-winged Sharpshooter, Homalodisca Vitripennis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The epidemiology of Pierce’s disease of grape in California has changed over the last 10 years due to the introduction of an exotic vector, Homalodisca vitripennis. Although this insect is highly polyphagous, citrus is considered a preferred host of H. vitripennis and proximity to citrus has been i...

  6. Current situation of "Candidatus Liberibacter asiaticus" in Guangdong, P.R. China, where citrus huanglongbing was first described

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus Huanglongbing (HLB, yellow shoot disease) was observed in Guangdong Province, Peoples’ Republic of China in the late 1800s and is endemic there, particularly in the coastal Chaoshan and Pearl River Delta plains. Since the 1990s, the center of citrus production in Guangdong has gradually shif...

  7. Gene expression in Citrus sinensis (L.) Osbeck following infection with the bacterial pathogen Candidatus Liberibacter asiaticus causing Huanglongbing in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hunglongbing (HLB) (=citrus greening) is a destructive disease of citrus which is caused by a fastidious, phloem-inhabiting bacterium of the genus Candidatus Liberibacter. Large-scale analysis of gene expression changes in ‘Valencia’ orange leaves were studied during the course of 19 weeks after in...

  8. THE ENDOPHYTE CURTOBACTERIUM FLACCUMFACIENS REDUCES SYMPTOMS CAUSED BY XYLELLA FASTIDIOSA IN CATHARANTHUS ROSEUSAN ENDOPHYTIC BACTERIUM FROM CITRUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus variegated chlorosis (CVC) is a disease of sweet orange (Citrus sinensis (L.)) caused by Xylella fastidiosa subsp. pauca, a phytopathogenic bacterium that can infect all sweet orange cultivars. Sweet orange trees are sometimes observed to be infected by Xylella fastidiosa without showing seve...

  9. DETECTION OF CANDIDATUS LIBERIBACTER ASIATICUS FROM CITRUS HUANGLONGBING SAMPLES IN CHINA BY NESTED CONVENTIONAL AND REAL-TIME PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Candidatus Liberibacter asiaticus is one of the three known bacterial Candidatus species causing citrus Huanglongbing (HLB) or yellow shoot disease. HLB is highly destructive in citrus cultivation and is currently known to presence in Asia, Africa, South and North America. Pathogen detection plays a...

  10. Callose deposition and inhibited symplastic transport in the phloem of citrus leaves infected with Candidatus Liberibacter asiaticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a lethal disease of citrus, damaging citrus agriculture worldwide. A phloem-limited, alpha proteobacterium, Candidatus Liberibacter asiaticus (Las) is associated with HLB in North America. We examined Lasinfected (Las+) leaf phloem cells by microscopy methods to characterize p...

  11. Control of citrus postharvest decay by ammonia gas fumigation and its influence on the efficacy of the fungicide imazalil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The most important citrus postharvest diseases of arid citrus production areas, green mold and blue mold, caused by Penicillium digitatum and P. italicum, respectively, were effectively controlled by fumigations with ammonia alone at 3000 to 6000 µl/liter or at 1500 µl/liter when applied to fruit pr...

  12. Effects of the residual activity of foliar-applied insecticides on Asian citrus psyllid (Diaphorina citri) feeding behavior.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus greening disease, also known as Huanglongbing (HLB), is associated with a phloem-limited bacterium that is transmitted by Asian citrus psyllid, Diaphorina citri Kuwayama. Application of insecticides to reduce psyllid populations is one of the primary methods used for HLB management. However,...

  13. Association of ‘Candidatus Liberibacter asiaticus’, the causal agent of citrus huanglongbing in Murraya paniculata and Diaphorina citri in Thailand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Orange jasmine, Murraya paniculata, is a preferred alternative host for the Asian citrus psyllid, the primary vector of citrus Huanglongbing (HLB) disease caused by ‘Candidatus Liberibacter asiaticus’ (Las). M. paniculata plant samples and psyllids on the Murraya plants from ten diverse geographical...

  14. Molecular analyses revealed genetic complexity in Citrus tristeza virus Dekopon isolate and its aphid-transmitted progeny

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An assessment was made of the disease potential of a Citrus tristeza virus (CTV) isolate designated Dekopon found in a hybrid mandarin variety topworked in a citrus planting in Fresno County, CA. After aphid transmissions (AT), parental and AT isolates were analyzed by SSCP, genotyping with multipl...

  15. Effect of Liberibacter infection (Huanglongbing disease) of citrus on orange fruit physiology and fruit/fruit juice quality: chemical and physical analyses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) or greening disease was discovered in Florida several years ago and has since spread throughout the state. The disease is correlated to the presence of a gram-negative bacteria, Candididatus Liberibacter asiaticus (Las). This disease is not feasible to eradicate, thus, the indus...

  16. Annotation of gene function in citrus using gene expression information and co-expression networks

    PubMed Central

    2014-01-01

    Background The genus Citrus encompasses major cultivated plants such as sweet orange, mandarin, lemon and grapefruit, among the world’s most economically important fruit crops. With increasing volumes of transcriptomics data available for these species, Gene Co-expression Network (GCN) analysis is a viable option for predicting gene function at a genome-wide scale. GCN analysis is based on a “guilt-by-association” principle whereby genes encoding proteins involved in similar and/or related biological processes may exhibit similar expression patterns across diverse sets of experimental conditions. While bioinformatics resources such as GCN analysis are widely available for efficient gene function prediction in model plant species including Arabidopsis, soybean and rice, in citrus these tools are not yet developed. Results We have constructed a comprehensive GCN for citrus inferred from 297 publicly available Affymetrix Genechip Citrus Genome microarray datasets, providing gene co-expression relationships at a genome-wide scale (33,000 transcripts). The comprehensive citrus GCN consists of a global GCN (condition-independent) and four condition-dependent GCNs that survey the sweet orange species only, all citrus fruit tissues, all citrus leaf tissues, or stress-exposed plants. All of these GCNs are clustered using genome-wide, gene-centric (guide) and graph clustering algorithms for flexibility of gene function prediction. For each putative cluster, gene ontology (GO) enrichment and gene expression specificity analyses were performed to enhance gene function, expression and regulation pattern prediction. The guide-gene approach was used to infer novel roles of genes involved in disease susceptibility and vitamin C metabolism, and graph-clustering approaches were used to investigate isoprenoid/phenylpropanoid metabolism in citrus peel, and citric acid catabolism via the GABA shunt in citrus fruit. Conclusions Integration of citrus gene co-expression networks, functional enrichment analysis and gene expression information provide opportunities to infer gene function in citrus. We present a publicly accessible tool, Network Inference for Citrus Co-Expression (NICCE, http://citrus.adelaide.edu.au/nicce/home.aspx), for the gene co-expression analysis in citrus. PMID:25023870

  17. Identifiction and Characterization of Huanglongbing Bacterium in Pummelo [citrus grandis (L.) Osbeck] from Multiple Locations in Guangdong, P.R. China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) or citrus greening disease, caused by Candidatus Liberibacter spp., is highly destructive to citrus production in Asia, Africa, and South America. The disease has recently been found in North America (Florida). While primarily affecting sweet orange and mandarin, HLB has been sus...

  18. Nested PCR is essential for the detection of extremely low titer of Candidatus Liberibacter asiaticus from citrus and its vector psyllid Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB), transmitted by the psyllids Diaphorina citri and Trioza erytreae, is one of the most devastating diseases of citrus worldwide. The disease is associated with three different species of Candidatus Liberibacter: Ca. L. asiaticus (Las), Ca. L. americanus and Ca. L. africanu...

  19. Dispersal of Xanthomonas citri subsp. citri bacteria downwind from harvested, infected fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas axonopodis pv. citri , Xac) is a bacterial disease that severely damages citrus crops. Its recent introduction to Florida has created difficulties with international and domestic trade and movement of citrus material. This study examined the potential dispersal of bacteri...

  20. Intentional coverage gaps reduce cost of mating disruption for Phyllocnistis citrella (Lepidoptera: Gracillariidae) in citrus.

    PubMed

    Lapointe, S L; Stelinski, L L; Keathley, C P; Mafra-Neto, A

    2014-04-01

    The leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is a global pest of citrus and contributes to the incidence and severity of citrus bacterial canker. SPLAT CLM (ISCA Technologies, Riverside, CA) is an emulsified wax that provides sustained release of (Z,Z,E)-7,11,13-hexadecatrienal, the major component of P. citrella sex pheromone. Trials in commercial orchards demonstrated that SPLAT CLM applied to plots of varying width resulted in disruption of trap catch of male P. citrella within treated rows and across untreated rows adjacent to treated rows. SPLAT CLM applied to plots of constant width (10 rows) disrupted trap catch across an untreated gap as the square of the width of the gap. Similarly, the ability of the pheromone source in treated rows to disrupt trap catch across untreated gaps of constant size declined as the square of the width of adjacent treated areas. A coverage pattern of 4 rows skipped for every 10 treated rows resulted in a 4% reduction of trap shutdown, and reduced the product and application costs by 29%. Mining incidence by P. citrella in treated rows was reduced by 53% compared with untreated areas. Intentional coverage gaps can significantly reduce the cost of mating disruption. Commercial lures for P. citrella used in this study were highly potent with respect to attracting males. Each lure was approximately 10(3) times as attractive as an individual P. citrella female. Disruption of trap catch using commercial lures may underestimate actual mating disruption achieved in the field. PMID:24772554

  1. Developing an understanding of cross-protection by Citrus tristeza virus

    PubMed Central

    Folimonova, Svetlana Y.

    2013-01-01

    Citrus tristeza virus (CTV) causes two citrus diseases that have caused devastating losses in global citrus production. The first disease is quick decline of trees propagated on the sour orange rootstock. The second disease is stem pitting, which severely affects a number of economically important citrus varieties regardless of the rootstock used and results in reduced tree growth and vigor as well as in reduced fruit size and quality. Both diseases continue to invade new areas. While quick decline could be effectively managed by the use of resistant and/or tolerant rootstocks, the only means to protect commercial citrus against endemic stem pitting isolates of CTV has been cross-protection with mild isolates of the virus. In some citrus areas cross-protection has been successful and allowed production of certain citrus cultivars despite the presence of severe stem pitting isolates in those regions. However, many other attempts to find isolates that would provide sustained protection against aggressive isolates of the virus had failed. In general, there has been no understanding why some mild isolates were effective and others failed to protect. We have been working on the mechanism of cross-protection by CTV. Recent considerable progress has significantly advanced our understanding of how cross-protection may work in the citrus/CTV pathosystem. As we demonstrated, only isolates that belong to the same strain of the virus cross protect against each other, while isolates from different strains do not. We believe that the results of our research could now make finding protecting isolates relatively straightforward. This review discusses some of the history of CTV cross-protection along with the recent findings and our “recipe” for selection of protecting isolates. PMID:23577008

  2. The Eucalyptus canker pathogen Holocryphia eucalypti on Eucalyptus in New Zealand

    E-print Network

    The Eucalyptus canker pathogen Holocryphia eucalypti on Eucalyptus in New Zealand M. Gryzenhout, South Africa. C Scion Research, New Zealand Forest Institute Ltd, Rotorua, New Zealand. D Corresponding and morphological characterisation, we show for the first time that H. eucalypti is present in New Zealand

  3. Canker and twig dieback of blueberry caused by Pestalotiopsis spp. and a Truncatella sp. in Chile

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blueberry (Vaccinium spp.) has great economic importance in Chile, currently with about 8,500 ha being cultivated. Recently, the presence of canker and dieback symptoms has been observed along the productive blueberry zone of Chile extending from the V Region (32º49´ South lat.) in the north to the ...

  4. Report on the National Survey to Assess the Presence of Bleeding Canker of Horse Chestnut Trees

    E-print Network

    Report on the National Survey to Assess the Presence of Bleeding Canker of Horse Chestnut Trees trees from 128 rural sites and 1244 trees in 112 urban sites were inspected. All regions had some symptomatic trees and overall, 44% of the trees inspected in the rural environment and 55% of the urban trees

  5. DETECTION OF BRENNARIA RUBRIFACIENS THE CAUSATIVE AGENT OF DEEP BARK CANKER (DBC)OF WALNUT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    DBC afflicts English walnut cultivars and is characterized by late onset in trees greater than 15 years old. Symptoms include deep bleeding vertical cankers that exude a bacterial-laden reddish brown sap. We have developed a robust PCR-based technique to detect B. rubrifaciens in soil and symptomles...

  6. Evidence for a new introduction of the pitch canker fungus Fusarium circinatum in South Africa

    E-print Network

    Evidence for a new introduction of the pitch canker fungus Fusarium circinatum in South Africa E. T of Pinus species in many parts of the world. The fungus was first recorded in South Africa in 1990 of the fungus elsewhere in South Africa. However, limited genetic structure was found within the respective WCP

  7. 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...

  8. 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...

  9. Bylaws of the Citrus Research & Education Center

    E-print Network

    Jawitz, James W.

    Bylaws of the Citrus Research & Education Center University of Florida December 12th , 2012 Preamble The shared goals of the faculty and administration of the Citrus Research & Education Center are to discover and deliver innovative solutions that empower citrus and other agricultural interests to conduct

  10. Citrus College Portland State University Transfer Worksheet

    E-print Network

    Caughman, John

    Citrus College Portland State University Transfer Worksheet If you are taking classes that are part of the Intersegmental General Education Transfer Curriculum (IGETC) at Citrus College (CC), you can rest assured. General Education Requirements #12;Citrus College Portland State University 2. DEGREE REQUIREMENTS

  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. SCREENING OF ANTI-BACTERIAL PEPTIDES IN CITRUS TREES FOR ACTIVITY AGAINST CANDIDATUS LIBERIBACTER ASIATICUS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing disease (HLB) has been recently reported from both Brazil and Florida. Because of the uniquely destructive nature of the disease, and the present lack of options to control the disease, new approaches are needed. The bacterium that causes HLB, Candidatus Liberibacter asiaticus, ...

  13. 7 CFR 301.75-16 - Payments for the recovery of lost production income.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...the result of the removal of commercial citrus trees to control citrus canker. (a) Eligibility...the result of the removal of commercial citrus trees to control citrus canker if the trees were removed pursuant to a public order...

  14. 7 CFR 301.75-16 - Payments for the recovery of lost production income.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...the result of the removal of commercial citrus trees to control citrus canker. (a) Eligibility...the result of the removal of commercial citrus trees to control citrus canker if the trees were removed pursuant to a public order...

  15. 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

  16. Florida Citrus Industry Oral Histories

    NSDL National Science Digital Library

    What's so special about oranges? They are a major cash crop for Florida and other warm weather places, and this fascinating oral history project from the University of South Florida (USF) explores the very nature of this industry. Working together with the USF's Patel Center for Global Studies, oral historian William Mansfield conducted 20 interviews regarding the impact of globalization on the Florida citrus industry. Visitors can listen to or read the interviews, as well as look over the online exhibition, "Selling Sunshine: Florida's Citrus Industry." The exhibition details Florida's unique relationship with the citrus industry, incorporating documents, promotional material, and post cards with its information. The website hosts a remarkable collection that will be of interest to oral historians, folks with an interest in Florida, and many others.

  17. Effect of liberibacter infection (huanglongbing disease) of citrus on orange fruit physiology and fruit/fruit juice quality: chemical and physical analyses.

    PubMed

    Baldwin, Elizabeth; Plotto, Anne; Manthey, John; McCollum, Greg; Bai, Jinhe; Irey, Mike; Cameron, Randall; Luzio, Gary

    2010-01-27

    More than 90% of oranges in Florida are processed, and since Huanglongbing (HLB) disease has been rumored to affect fruit flavor, chemical and physical analyses were conducted on fruit and juice from healthy (Las -) and diseased (Las +) trees on three juice processing varieties over two seasons, and in some cases several harvests. Fruit, both asymptomatic and symptomatic for the disease, were used, and fresh squeezed and processed/pasteurized juices were evaluated. Fruit and juice characteristics measured included color, size, solids, acids, sugars, aroma volatiles, ascorbic acid, secondary metabolites, pectin, pectin-demethylating enzymes, and juice cloud. Results showed that asymptomatic fruit from symptomatic trees were similar to healthy fruit for many of the quality factors measured, but that juice from asymptomatic and especially symptomatic fruits were often higher in the bitter compounds limonin and nomilin. However, values were generally below reported taste threshold levels, and only symptomatic fruit seemed likely to cause flavor problems. There was variation due to harvest date, which was often greater than that due to disease. It is likely that the detrimental flavor attributes of symptomatic fruit (which often drop off the tree) will be largely diluted in commercial juice blends that include juice from fruit of several varieties, locations, and seasons. PMID:20030384

  18. 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...

  19. Double pruning to prevent trunk diseases in Washington vineyards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Trunk diseases (aka wood-canker diseases) present a serious challenge to vineyard productivity and longevity. There are four main trunk diseases: Botryosphaeria dieback, Esca, Eutypa dieback, and Phomopsis dieback. The causal fungi (e.g., Eutypa lata, Neofusicoccum parvum) establish chronic infectio...

  20. Materials for Controlling Asian Citrus Psyllid (Carrier of Citrus Greening) in Home Landscapes, Gardens, & Non-Commercial Orchards

    E-print Network

    Mukhtar, Saqib

    Materials for Controlling Asian Citrus Psyllid (Carrier of Citrus Greening) in Home Landscapes, Gardens, & Non-Commercial Orchards Asian Citrus Psyllid may infest a citrus tree throughout the year of the products listed below. Citrus growers should therefore monitor their trees regularly for the presence

  1. Detection and damage assessment of citrus tree losses with aerial color infrared photography /ACIR/

    NASA Technical Reports Server (NTRS)

    Blazquez, C. H.; Horn, F. W., Jr.; Edwards, G. J.

    1981-01-01

    Detection and disease damage assessment of citrus tree losses in a Florida citrus grove were made by establishing a registration (grove site location) coordinate system, developing a damage assessment system, and testing sequential aerial color infrared (ACIR) photography at the scale of 1 in. = 333 ft (2.5 cm = 100 m) during the winter, spring, and summer seasons of 1978 and spring of 1979. Spring photography was the easiest to photo interpret, showed the greatest differences between healthy and diseased trees, and had the least shadow and background interference for photo interpretation. Trees showing slight disease damage were detected in ACIR before they were found in ground surveys.

  2. A cellular automata model for citrus variegated chlorosis

    NASA Astrophysics Data System (ADS)

    Martins, M. L.; Ceotto, G.; Alves, S. G.; Bufon, C. C. B.; Silva, J. M.; Laranjeira, F. F.

    2001-06-01

    A review of the main results obtained by a cellular automata model recently proposed to analyze the progress of citrus variegated chlorosis epidemics is done. In this model epidemiological and environmental features, such as motility of sharpshooter vectors which perform Lévy flights, hydric and nutritional level of plant stress and seasonal climatic effects, are included. The observed epidemics data were quantitatively reproduced by the proposed model varying the parameters controlling vectors motility, plant stress and initial population of diseased plants.

  3. Retracted stylets in nymphs of the Asian citrus psyllid are held externally against the clypeus by a special paired organ not found in the adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Differences in ultrastructure of the mouthparts in nymphs and adults of the Asian citrus psyllid Diaphorina citri (Hemiptera, Psyllidae), vector of the bacterium associated with citrus huanglongbing disease, were studied using scanning electron microscopy. The number of sensilla on the labial tip in...

  4. Efficacy of integrated postharvest treatments against mixed innoculations of penicillium digitatum and geotrichum citri?aurantii in ‘leng’ navel oranges (citrus sinensis)

    Microsoft Academic Search

    N. M. Cunningham; P. D. Taverner

    2007-01-01

    Green mould (Penicillium digitatum) and sour rot (Geotrichum citri?aurantii) in early season, thin?skinned navel oranges (Citrus sinensis) are of serious concern to the Australian citrus export industry. The pathogen causing the disease sour rot is particularly problematic because the control method for the Australian domestic market is to use fungicides containing guazatine, a chemical that is restricted for important export

  5. A novel emerging virus with indistinguishable symptoms and genome structure similar to citrus leprosis virus C identified by small RNA deep sequencing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus leprosis disease (CiLD) in Colombia was previously shown to be caused by cytoplasmic Citrus leprosis virus (CiLV-C). In 2011, ELISA and RT-PCR based diagnostic methods failed to identify CiLV-C from CiLD samples, but virions similar to CiLV-C were observed in cytoplasm of the symptomatic leav...

  6. A new method for short-term rearing of psyllid adults and nymphs on detached citrus leaves and detached young terminal shoots

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using whole citrus plants for rearing of psyllids for biological studies or for studying vector relations of the huanglongbing disease takes considerable space, time and other resources. We have developed a new and simpler method for short-term rearing of the Asian citrus psyllid Diaphorina citri us...

  7. Innate and conditioned responses to chemosensory and visual cues in Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), vector of Huanglongbing pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asian citrus psyllid (Diaphorina citri) transmits the causal agent of Huanglongbing, a devastating disease that threatens citrus trees worldwide. This psyllid oviposits and develops only on the emerging shoots of its rutaceous host-plants; however, little is known about the mechanisms underlying its...

  8. 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...

  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. 7 CFR 319.56-41 - Citrus from Peru.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...and Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ), limes (C. aurantiifolia ), mandarins or tangerines (C. reticulata ), sweet oranges (C. sinensis ), and tangelos (Citrus tangelo ) may be...

  11. 7 CFR 319.56-41 - Citrus from Peru.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...and Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ), limes (C. aurantiifolia ), mandarins or tangerines (C. reticulata ), sweet oranges (C. sinensis ), and tangelos (Citrus tangelo ) may be...

  12. 7 CFR 319.56-41 - Citrus from Peru.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...and Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ), limes (C. aurantiifolia ), mandarins or tangerines (C. reticulata ), sweet oranges (C. sinensis ), and tangelos (Citrus tangelo ) may be...

  13. 7 CFR 319.56-41 - Citrus from Peru.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...and Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ), limes (C. aurantiifolia ), mandarins or tangerines (C. reticulata ), sweet oranges (C. sinensis ), and tangelos (Citrus tangelo ) may be...

  14. 7 CFR 319.56-41 - Citrus from Peru.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...and Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ), limes (C. aurantiifolia ), mandarins or tangerines (C. reticulata ), sweet oranges (C. sinensis ), and tangelos (Citrus tangelo ) may be...

  15. 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

  16. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Duties of Citrus Administrative Committee. 905.31...Administrative Bodies § 905.31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus Administrative Committee:...

  17. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Duties of Citrus Administrative Committee. 905.31...Administrative Bodies § 905.31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus Administrative Committee:...

  18. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Duties of Citrus Administrative Committee. 905.31...Administrative Bodies § 905.31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus Administrative Committee:...

  19. 1-Methylcyclopropene Applications in Preharvest Systems: Focus on Citrus

    E-print Network

    Burns, Jacqueline K.

    1-Methylcyclopropene Applications in Preharvest Systems: Focus on Citrus Jacqueline K. Burns1 University of Florida, IFAS, Horticultural Sciences Department, Citrus Research and Education Center, 700-MCP to prevent unwanted defoliation using ethephon to loosen mature citrus fruit is presented

  20. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Duties of Citrus Administrative Committee. 905.31...Administrative Bodies § 905.31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus Administrative Committee:...

  1. 7 CFR 905.31 - Duties of Citrus Administrative Committee.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Duties of Citrus Administrative Committee. 905.31...Administrative Bodies § 905.31 Duties of Citrus Administrative Committee. It shall be the duty of the Citrus Administrative Committee:...

  2. Spiroplasma citri Infection Affects Yield and Fruit Quality in Commercial Citrus Grove in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The chronic effects of stubborn disease, caused by Spiroplasma citri, on citrus include stunting, abnormal fruit shape and reduced yield. However, disease impact have never been quantified in a commercial grove. The objective of this work was to measure the impact of S. citri infection on tree dev...

  3. 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...

  4. Treponemes-Infected Canker in a Japanese Racehorse: Efficacy of Maggot Debridement Therapy

    PubMed Central

    KUWANO, Atsutoshi; NIWA, Hidekazu; HIGUCHI, Tohru; MITSUI, Hideya; AGNE, Robert A.

    2012-01-01

    A 3-year-old thoroughbred colt presented with canker on its left hind foot. Subsequent development of cottage cheese-like horns and dermatitis disturbed healing, despite the use of miscellaneous orthodox treatment approaches to the lesions. Histological examination revealed exudative and suppurative dermatitis, and proliferatively suppurative epidermitis infected with helically coiled treponemes. Total debridement under general anesthesia led to a temporary improvement, but the ground surface regenerated abnormal epidermis similar to that observed initially after surgery. Maggot debridement therapy (MDT) was attempted, which removed all the abnormal tissue. After MDT, general farriery trimming helped to correct the distorted ground surface, and the horse returned to constant training and eventually raced. This case shows that MDT was successfully used for treatment of an intractable and treponemes-infected canker. PMID:24833994

  5. Past and future of a century old Citrus tristeza virus collection: a California citrus germplasm tale

    PubMed Central

    Wang, Jinbo; Bozan, Orhan; Kwon, Sun-Jung; Dang, Tyler; Rucker, Tavia; Yokomi, Raymond K.; Lee, Richard F.; Folimonova, Svetlana Y.; Krueger, Robert R.; Bash, John; Greer, Greg; Diaz, James; Serna, Ramon; Vidalakis, Georgios

    2013-01-01

    Citrus tristeza virus (CTV) isolates collected from citrus germplasm, dooryard and field trees in California from 1914 have been maintained in planta under quarantine in the Citrus Clonal Protection Program (CCPP), Riverside, California. This collection, therefore, represents populations of CTV isolates obtained over time and space in California. To determine CTV genetic diversity in this context, genotypes of CTV isolates from the CCPP collection were characterized using multiple molecular markers (MMM). Genotypes T30, VT, and T36 were found at high frequencies with T30 and T30+VT genotypes being the most abundant. The MMM analysis did not identify T3 and B165/T68 genotypes; however, biological and phylogenetic analysis suggested some relationships of CCPP CTV isolates with these two genotypes. Phylogenetic analysis of the CTV coat protein (CP) gene sequences classified the tested isolates into seven distinct clades. Five clades were in association with the standard CTV genotypes T30, T36, T3, VT, and B165/T68. The remaining two identified clades were not related to any standard CTV genotypes. Spatiotemporal analysis indicated a trend of reduced genotype and phylogenetic diversity as well as virulence from southern California (SC) at early (1907–1957) in comparison to that of central California (CC) isolates collected from later (1957–2009) time periods. CTV biological characterization also indicated a reduced number and less virulent stem pitting (SP) CTV isolates compared to seedling yellows isolates introduced to California. This data provides a historical insight of the introduction, movement, and genetic diversity of CTV in California and provides genetic and biological information useful for CTV quarantine, eradication, and disease management strategies such as CTV-SP cross protection. PMID:24339822

  6. 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

  7. Fungal Diversity Diseases of eucalypt plantations in China: challenges and opportunities

    E-print Network

    diseases encountered in China are bacterial wilt caused by Ralstonia solanacearum, stem cankers caused of Eucalyptus fungal diseases has been made. The best known disease of eucalypts in China is bacterial wiltFungal Diversity 1 Diseases of eucalypt plantations in China: challenges and opportunities Zhou, X

  8. Citrus paradisi and Citrus sinensis flavonoids: Their influence in the defence mechanism against Penicillium digitatum

    Microsoft Academic Search

    A. Ortuño; A. Báidez; P. Gómez; M. C. Arcas; I. Porras; A. García-Lidón; J. A. Del Río

    2006-01-01

    Citrus peel is rich in flavanone glycosides and polymethoxyflavones. In view of their importance for industrial application as well as for their pharmacological properties, their content was analyzed in the mature fruits of several Citrus paradisi (grapefruit) and Citrus sinensis (orange) varieties, with a view to select the most interesting for isolation. The results shows that the Star Ruby grapefruit

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  10. Effects of soil-applied imidacloprid on Asian citrus psyllid (Hemiptera: Psyllidae) feeding behavior.

    PubMed

    Serikawa, R H; Backus, E A; Rogers, M E

    2012-10-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is one of the most important pests of citrus (Citrus spp.) because of its status as a vector of Candidatus Liberibacter asiaticus (Las), the bacterium associated with citrus greening disease. The use of insecticides for vector control is the primary method of managing the spread of this pathogen. Imidacloprid is an insecticide commonly applied to the root zone of young citrus trees to provide systemic protection from pests. The effects of imidacloprid on feeding behavior of D. citri have not been studied in much detail. The purpose of this study was to examine the effects of imidacloprid application on feeding behavior of D. citri and to determine whether use of this systemic insecticide could have any effect on pathogen transmission by D. citri. A direct current electrical penetration graph monitor was used to record D. citri feeding behaviors for 12-h periods on mature and young leaves of imidacloprid-treated and -untreated citrus seedlings. Overall, compared with untreated plants, the feeding behavior of D. citri was disrupted on imidacloprid-treated plants via reduction in the number of probes, as well as durations of average probes, initial stylet contact with phloem, phloem salivation, and phloem ingestion. The results of this study demonstrate that soil applications of imidacloprid can reduce the probability of citrus plants becoming inoculated with Las through a reduction in the number and duration of phloem salivation events by D. citri. Furthermore, Las acquisition from infected citrus is greatly reduced as a result of decreased phloem ingestion by D. citri on imidacloprid-treated plants. PMID:23156142

  11. Three homopteran pests of citrus as prey for the convergent lady beetle: suitability and preference.

    PubMed

    Qureshi, Jawwad A; Stansly, Philip A

    2011-12-01

    The convergent lady beetle, Hippodamia convergens Guérin-Méneville (Coleoptera: Coccinellidae), is an important predator of soft-bodied insect pests in many regions of the United States, but generally uncommon in Florida citrus. Certain citrus producers in Florida recently initiated releases of commercially available H. convergens from California against the Asian citrus psyllid Diaphorina citri Kuwayama, vector of Huanglongbing or citrus greening disease. However, there is little information on potential efficacy of this predator against the psyllid or other pests of citrus. Preference, development, and reproduction by H. convergens was evaluated on freshly collected nymphs of D. citri, brown citrus aphid Toxoptera citricida Kirkaldy, green citrus aphid Aphis spiraecola Patch, and frozen eggs of the flour moth Ephestia kuehniella Zeller. Larvae preferred D. citri over T. citricida in two-way choice tests and consumed more D. citri or A. spiraecola than T. citricida in no-choice tests. Adults consumed equal numbers of all three species in both tests. Development times of larvae at 25.5±0.05°C on A. spiraecola were longer than on the other three diets. Larval survival and pupation times did not differ among diets. Females lived longer than males irrespective of diet, and longevity of both genders was greatly increased on E. kuehniella compared with D. citri and A. spiraecola. Life table analysis indicated that H. convergens should increase on all three species, with a greater potential on psyllids than aphids. Further studies are warranted to assess establishment and persistence of this potential biological control agent in the Florida citrus environment. PMID:22217767

  12. Pseudomonas syringae pv. actinidiae (PSA) Isolates from Recent Bacterial Canker of Kiwifruit Outbreaks Belong to the Same Genetic Lineage

    PubMed Central

    Taratufolo, Maria C.; Cai, Rongman; Almeida, Nalvo F.; Goodman, Tokia; Guttman, David S.; Vinatzer, Boris A.; Balestra, Giorgio M.

    2012-01-01

    Intercontinental spread of emerging plant diseases is one of the most serious threats to world agriculture. One emerging disease is bacterial canker of kiwi fruit (Actinidia deliciosa and A. chinensis) caused by Pseudomonas syringae pv. actinidiae (PSA). The disease first occurred in China and Japan in the 1980s and in Korea and Italy in the 1990s. A more severe form of the disease broke out in Italy in 2008 and in additional countries in 2010 and 2011 threatening the viability of the global kiwi fruit industry. To start investigating the source and routes of international transmission of PSA, genomes of strains from China (the country of origin of the genus Actinidia), Japan, Korea, Italy and Portugal have been sequenced. Strains from China, Italy, and Portugal have been found to belong to the same clonal lineage with only 6 single nucleotide polymorphisms (SNPs) in 3,453,192 bp and one genomic island distinguishing the Chinese strains from the European strains. Not more than two SNPs distinguish each of the Italian and Portuguese strains from each other. The Japanese and Korean strains belong to a separate genetic lineage as previously reported. Analysis of additional European isolates and of New Zealand isolates exploiting genome-derived markers showed that these strains belong to the same lineage as the Italian and Chinese strains. Interestingly, the analyzed New Zealand strains are identical to European strains at the tested SNP loci but test positive for the genomic island present in the sequenced Chinese strains and negative for the genomic island present in the European strains. Results are interpreted in regard to the possible direction of movement of the pathogen between countries and suggest a possible Chinese origin of the European and New Zealand outbreaks. PMID:22590555

  13. Genetic control of Eucalyptus urophylla and E. grandis resistance to canker caused by Chrysoporthe cubensis

    PubMed Central

    2010-01-01

    Chrysophorte cubensis induced canker occurs in nearly all tropical and subtropical regions where eucalypts are planted, causing losses in both wood quality and volume productivity, especially so in the warmer and more humid regions of Brazil. The wide inter and intra-specific genetic variability of resistance to canker among Eucalyptus species facilitates the selection of resistant plants. In this study, we evaluated resistance to this pathogen in five Eucalyptus grandis (G) and 15 E. urophylla (U) trees, as well as in 495 individuals from 27 progenies derived from crosses between the trees. In the field, six-months-old test seedlings were inoculated with C. cubensis. Lesion length in the xylem and bark was measured eight months later. The results demonstrated that xylem lesions could preferentially be used for the selection of resistant clones. Eight trees (7 U and 1 G) were susceptible, and the remainder (8 U and 4 G) resistant. Individual narrow and broad sense heritability estimates were 17 and 81%, respectively, thereby suggesting that canker resistance is quantitative and highly dependent on dominance and epistasis. PMID:21637427

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

    PubMed

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

    2012-09-01

    The bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae is a severe threat to kiwifruit production worldwide. Many aspects of P. syringae pv. actinidiae biology and epidemiology still require in-depth investigation. The infection by and spread of P. syringae pv. actinidiae in xylem and phloem was investigated by carrying out artificial inoculation experiments with histological and dendrochronological analyses of naturally diseased plants in Italy. We found that the bacterium can infect host plants by entering natural openings and lesions. In naturally infected kiwifruit plants, P. syringae pv. actinidiae is present in the lenticels as well as in the dead phloem tissue beneath the lenticels, surrounded by a lesion in the periderm which appears to indicate the importance of lenticels to kiwifruit infection. Biofilm formation was observed outside and inside plants. In cases of advanced stages of P. syringae pv. actinidiae infection, neuroses of the phloem occur, which are followed by cambial dieback and most likely by infection of the xylem. Anatomical changes in wood such as reduced ring width, a drastic reduction in vessel size, and the presence of tyloses were observed within several infected sites. In the field, these changes occur only a year after the first leaf symptoms are observed suggesting a significant time lapse between primary and secondary symptoms. It was possible to study the temporal development of P. syringae pv. actinidiae-induced cambial dieback by applying dendrochronology methods which revealed that cambial dieback occurs only during the growing season. PMID:22713076

  15. Stylet morphometrics and citrus leaf vein structure in relation to feeding behavior of the Asian citrus psyllid Diaphorina citri, vector of citrus huanglongbing bacterium.

    PubMed

    Ammar, El-Desouky; Hall, David G; Shatters, Robert G

    2013-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae), is the primary vector of the phloem-limited bacterium Candidatus Liberibacter asiaticus (LAS) associated with huanglongbing (HLB, citrus greening), considered the world's most serious disease of citrus. Stylet morphometrics of ACP nymphs and adults were studied in relation to citrus vein structure and to their putative (histologically verified) feeding sites on Valencia orange leaves. ACP nymphs preferred to settle and feed on the lower (abaxial) side of young leaves either on secondary veins or on the sides of the midrib, whereas adults preferred to settle and feed on the upper (adaxial) or lower secondary veins of young or old leaves. Early instar nymphs can reach and probe the phloem probably because the distance to the phloem is considerably shorter in younger than in mature leaves, and is shorter from the sides of the midrib compared to that from the center. Additionally, the thick-walled 'fibrous ring' (sclerenchyma) around the phloem, which may act as a barrier to ACP stylet penetration into the phloem, is more prominent in older than in younger leaves and in the center than on the sides of the midrib. The majority (80-90%) of the salivary sheath termini produced by ACP nymphs and adults that reached a vascular bundle were associated with the phloem, whereas only 10-20% were associated with xylem vessels. Ultrastructural studies on ACP stylets and LAS-infected leaves suggested that the width of the maxillary food canal in first instar nymphs is wide enough for LAS bacteria to traverse during food ingestion (and LAS acquisition). However, the width of the maxillary salivary canal in these nymphs may not be wide enough to accommodate LAS bacteria during salivation (and LAS inoculation) into host plants. This may explain the inability of early instar nymphs to transmit LAS/HLB in earlier reports. PMID:23555830

  16. Stylet Morphometrics and Citrus Leaf Vein Structure in Relation to Feeding Behavior of the Asian Citrus Psyllid Diaphorina citri, Vector of Citrus Huanglongbing Bacterium

    PubMed Central

    Ammar, El-Desouky; Hall, David G.; Shatters, Robert G.

    2013-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae), is the primary vector of the phloem-limited bacterium Candidatus Liberibacter asiaticus (LAS) associated with huanglongbing (HLB, citrus greening), considered the world’s most serious disease of citrus. Stylet morphometrics of ACP nymphs and adults were studied in relation to citrus vein structure and to their putative (histologically verified) feeding sites on Valencia orange leaves. ACP nymphs preferred to settle and feed on the lower (abaxial) side of young leaves either on secondary veins or on the sides of the midrib, whereas adults preferred to settle and feed on the upper (adaxial) or lower secondary veins of young or old leaves. Early instar nymphs can reach and probe the phloem probably because the distance to the phloem is considerably shorter in younger than in mature leaves, and is shorter from the sides of the midrib compared to that from the center. Additionally, the thick-walled ‘fibrous ring’ (sclerenchyma) around the phloem, which may act as a barrier to ACP stylet penetration into the phloem, is more prominent in older than in younger leaves and in the center than on the sides of the midrib. The majority (80–90%) of the salivary sheath termini produced by ACP nymphs and adults that reached a vascular bundle were associated with the phloem, whereas only 10–20% were associated with xylem vessels. Ultrastructural studies on ACP stylets and LAS-infected leaves suggested that the width of the maxillary food canal in first instar nymphs is wide enough for LAS bacteria to traverse during food ingestion (and LAS acquisition). However, the width of the maxillary salivary canal in these nymphs may not be wide enough to accommodate LAS bacteria during salivation (and LAS inoculation) into host plants. This may explain the inability of early instar nymphs to transmit LAS/HLB in earlier reports. PMID:23555830

  17. Citrus Allergy from Pollen to Clinical Symptoms

    PubMed Central

    Iorio, Rosa Anna; Del Duca, Stefano; Calamelli, Elisabetta; Pula, Chiara; Lodolini, Magda; Scamardella, Fortuna; Pession, Andrea; Ricci, Giampaolo

    2013-01-01

    Allergy to citrus fruits is often associated with pollinosis and sensitization to other plants due to a phenomenon of cross-reactivity. The aims of the present study were to highlight the cross-reactivity among citrus and the major allergenic pollens/fruits, throughout clinical and molecular investigations, and to evaluate the sensitization frequency to citrus fruits in a population of children and adults with pollinosis. We found a relevant percentage of sensitisation (39%) to citrus fruits in the patients recruited and in all of them the IgE-mediated mechanism has been confirmed by the positive response to the prick-to-prick test. RT-PCR experiments showed the expression of Cit s 1, Cit s 3 and a profilin isoform, already described in apple, also in Citrus clementine pollen. Data of multiple sequence alignments demonstrated that Citrus allergens shared high percentage identity values with other clinically relevant species (i.e. Triticum aestivum, Malus domestica), confirming the possible cross-allergenicity citrus/grasses and citrus/apple. Finally, a novelty of the present work has been the expression of two phospholipaseA2 isoforms (PLA2 ? and ?) in Citrus as well as in Triticum pollens; being PLA2 able to generate pro-inflammatory factors, this enzyme could participate in the activation of the allergenic inflammatory cascade. PMID:23308273

  18. COMPARATIVE EPIDEMIOLOGY OF CTV IN PLANTINGS OF VARIOUS CITRUS SPECIES IN COSTA RICA AND LONG DISTANCE SPREAD BY THE BROWN CITRUS APHID

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Five 400-tree plots were established to compare the virus increase and spread of CTV among grapefruit, orange and lemon plots in San Carlos and Nicoya citrus producing areas of Costa Rica. Tree disease status was assayed semiannually over a five-year period via DAS-I ELISA using a monoclonal mixtur...

  19. Diversity of the citrus HLB bacterium, ‘Candidatus Liberibacter asiaticus’, in psyllids (Diaphorina citri) collected from Murraya paniculata and citrus spp. in Thailand

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Candidatus Liberibacter asiaticus’ (Las) is a phloem inhabiting bacterium that causes huanglongbing disease (HLB), also known as citrus greening associated with three species of a-Proteobacteria in the genus ‘Candidatus Liberibacter sp’. Prophage is an important genetic element of bacterial genomes...

  20. High codon adaptation in citrus tristeza virus to its citrus host

    PubMed Central

    2012-01-01

    Background Citrus tristeza virus (CTV), a member of the genus Closterovirus within the family Closteroviridae, is the causal agent of citrus tristeza disease. Previous studies revealed that the negative selection, RNA recombination and gene flow were the most important forces that drove CTV evolution. However, the CTV codon usage was not studied and thus its role in CTV evolution remains unknown. Results A detailed comparative analysis of CTV codon usage pattern was done in this study. Results of the study show that although in general CTV does not have a high degree of codon usage bias, the codon usage of CTV has a high level of resemblance to its host codon usage. In addition, our data indicate that the codon usage resemblance is only observed for the woody plant-infecting closteroviruses but not the closteroviruses infecting the herbaceous host plants, suggesting the existence of different virus-host interactions between the herbaceous plant-infecting and woody plant-infecting closteroviruses. Conclusion Based on the results, we suggest that in addition to RNA recombination, negative selection and gene flow, host plant codon usage selection can also affect CTV evolution. PMID:22698086

  1. 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.

  2. First Report of Nectria galligena Causing European Canker of Apple Trees in Ontario. A. R. Biggs, Agriculture Canada Research Station, Vineland Station, Ontario LOR 2EO. Plant

    E-print Network

    Biggs, Alan R.

    First Report of Nectria galligena Causing European Canker of Apple Trees in Ontario. A. R. Biggs for publication 19 July 1985. European canker of apple (Malus domestics Borkh. 'MacIntosh') caused by Nectria includes the apple-growing region of central Ontario. Reference: Booth, C. Commonw. Mycol. Inst. Pap. 73

  3. DEVELOPMENT OF A PCR-BASED METHOD FOR THE DETECTION OF BRENNARIA RUBRIFACIENS; THE CAUSAL AGENT OF DEEP BARK CANKER OF WALNUT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deep Bark Canker (DBC), caused by the bacterium Brenneria rubrifaciens (previously known as Erwinia rubrifaciens), afflicts English walnut cultivars and is characterized by late onset of symptoms in trees greater than 15 years old. These symptoms include deep bleeding vertical cankers throughout th...

  4. Cooperation in the Conservation of Citrus Genetic Resources: Riverside, California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A consortium of cooperating programs for the conservation and utilization of citrus genetic resources is centered at the University of California, Riverside (UCR). University units include the Citrus Clonal Protection Program (CCPP), Citrus Variety Collection (CVC), and Citrus Breeding Program (CBP...

  5. 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...

  6. Circular 1461 Precision Farming Adoption by Florida Citrus Producers

    E-print Network

    Lee, Wonsuk "Daniel"

    Circular 1461 Precision Farming Adoption by Florida Citrus Producers: Probit Model Analysis1 Brian of precision technologies in citrus production. Florida citrus production has experienced a rather volatile perfectly to the production scenario in citrus. If growers were able to manage their input applications

  7. RESEARCH ARTICLE Impact of water stress on citrus yield

    E-print Network

    Paris-Sud XI, Université de

    RESEARCH ARTICLE Impact of water stress on citrus yield Iván García-Tejero & Victor Hugo Durán. This work estimates the water production function in citrus trees, determining the relationship between% crop water evapotranspiration (ETC)) were implemented in 13-year-old citrus trees (Citrus sinensis L

  8. 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...

  9. 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…

  10. 7 CFR 301.75-6 - Interstate movement of regulated nursery stock from a quarantined area.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...of the United States except commercial citrus-producing areas if all of the following...not be obtained from properties where citrus canker is present. (4) All...

  11. 7 CFR 301.75-3 - Regulated articles.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...varieties, and hybrids of the genera Citrus and Fortunella, and all clones...inspector that it presents a risk of spread of citrus canker and the person in...

  12. 7 CFR 301.75-6 - Interstate movement of regulated nursery stock from a quarantined area.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...of the United States except commercial citrus-producing areas if all of the following...not be obtained from properties where citrus canker is present. (4) All...

  13. 7 CFR 301.75-3 - Regulated articles.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...varieties, and hybrids of the genera Citrus and Fortunella, and all clones...inspector that it presents a risk of spread of citrus canker and the person in...

  14. 7 CFR 301.75-3 - Regulated articles.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...varieties, and hybrids of the genera Citrus and Fortunella, and all clones...inspector that it presents a risk of spread of citrus canker and the person in...

  15. 7 CFR 301.75-6 - Interstate movement of regulated nursery stock from a quarantined area.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...of the United States except commercial citrus-producing areas if all of the following...not be obtained from properties where citrus canker is present. (4) All...

  16. 7 CFR 301.75-3 - Regulated articles.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...varieties, and hybrids of the genera Citrus and Fortunella, and all clones...inspector that it presents a risk of spread of citrus canker and the person in...

  17. 7 CFR 301.75-3 - Regulated articles.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...varieties, and hybrids of the genera Citrus and Fortunella, and all clones...inspector that it presents a risk of spread of citrus canker and the person in...

  18. 7 CFR 301.75-6 - Interstate movement of regulated nursery stock from a quarantined area.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...of the United States except commercial citrus-producing areas if all of the following...not be obtained from properties where citrus canker is present. (4) All...

  19. 7 CFR 301.75-6 - Interstate movement of regulated nursery stock from a quarantined area.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations...of the United States except commercial citrus-producing areas if all of the following...not be obtained from properties where citrus canker is present. (4) All...

  20. BIOLOGY AND MANAGEMENT OF REPLANT DISORDER AND LETHAL PHYTOPHTHORA CANKER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This research concerns biology and management of replant disease (RD), a complex problem that complicates an important process--orchard replacement. Orchard replacement forces difficult management decisions, including some related to scheduling (i.e., at what age should replacement occur, whether ti...

  1. Cryphonectria canker on Tibouchina in South Africa Henrietta MYBURG1

    E-print Network

    Africa. Pathogenicity tests on T. granulosa and E. grandis clones showed that the fungus from T of selected disease tolerant Eucalyptus clones and hybrids (Alfenas, Jeng & Hubbes 1983, Conradie, Swart, the fungus was reported from clove (Syzygium aromaticum) in Brazil. (Hodges, Alfenas & Ferreira 1986

  2. Development of rapid, sensitive and non-radioactive tissue-blot diagnostic method for the detection of citrus greening.

    PubMed

    Nageswara-Rao, Madhugiri; Miyata, Shin-Ichi; Ghosh, Dilip; Irey, Mike; Garnsey, Stephen M; Gowda, Siddarame

    2013-01-01

    Citrus huanglongbing (HLB or citrus greening) is one of the most devastating diseases of citrus worldwide. The disease is caused by Gram-negative, phloem-limited ?-proteobacterium, 'Candidatus Liberibacter asiaticus', vectored by the psyllid, Diaphorina citri Kuwayama. Citrus plants infected by the HLB bacterium may not show visible symptoms sometimes for years following infection and non-uniform distribution within the tree makes the detection of the pathogen very difficult. Efficient management of HLB disease requires rapid and sensitive detection early in the infection followed by eradication of the source of pathogen and the vector. The polymerase chain reaction (PCR) based method is most commonly employed for screening the infected/suspected HLB plants and psyllids. This is time consuming, cumbersome and not practical for screening large number of samples in the field. To overcome this, we developed a simple, sensitive, non-radioactive, tissue-blot diagnostic method for early detection and screening of HLB disease. Digoxigenin labeled molecular probes specific to 'Ca. L. asiaticus' nucleotide sequences have been developed and used for the detection of the pathogen of the HLB disease. The copy number of the target genes was also assessed using real-time PCR experiments and the optimized real-time PCR protocol allowed positive 'Ca. L. asiaticus' detection in citrus samples infected with 'Ca. L. asiaticus' bacterium. PMID:23660459

  3. First report of Candidatus Liberibacter asiaticus infecting citrus in the Dominican Republic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Real-time and conventional PCR were used to amplify sequences from the 16S rDNA and the outer membrane protein (omp) gene from nucleic acid extracts from 16 citrus samples from the Dominican Republic which displayed symptoms of the huanglungbing disease caused by the bacterium Candidatus Liberibacte...

  4. Candidatus Liberibacter asiaticus (CLas) titer in field HLB-exposed commercial citrus cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Incidence and severity of Huanglongbing (HLB) disease were assessed in April 2010 among eight citrus cultivars representing diverse scion types growing in commercial groves in Florida’s Indian River region, an area with high incidence of HLB. Twenty trees of each cultivar were rated for visual HLB s...

  5. Multilocus microsatellite analysis of ‘Candidatus Liberibacter asiaticus’ associated with citrus Huanglongbing worldwide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is one of the most destructive citrus diseases worldwide. In the United States (US), HLB is typically associated with the presence of a fastidious phloem-limited bacterium named ‘Candidatus Liberibacter asiaticus’, though other Liberibacter species also have been associated with ...

  6. An update on the effect of citrus greening on flavor and taste of orange juice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There have been some anecdotal reports that Huanglongbing (HLB) or citrus greening disease, recently introduced in Florida, may impart off flavor to orange juice. It is of interest to the processing industry to determine what affect fruit from trees of various stages of infection would have on proce...

  7. Fractionation of the secondary metabolites of orange (Citrus sinensis L.) leaves by fast centrifugal partition chromatography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is interest in the detection of changes in secondary metabolites in orange leaves in response to citrus greening disease. Conventional HPLC analysis readily provides detection of major phenolic compounds, but further, more detailed chromatographic analyses show many more compounds, to an exten...

  8. Penicillium digitatum suppresses production of hydrogen peroxide in host tissue during infection of citrus fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the development of green mold disease (Penicillium digitatum) on citrus fruit, there is little evidence of a host resistance response against the invading fungus. This suggests that P. digitatum has the ability to suppress host defenses. Current knowledge of plant-fungal interactions indica...

  9. 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...

  10. July/August 2007 ListProc Newsletter Feeding Winter Bees Seedless Citrus

    E-print Network

    Ferrara, Katherine W.

    ______________________________________________________________________________ ListProc Newsletter Feeding Winter Bees Seedless Citrus Disease Resistance in HB New Bee Diets of the list and your first and last names followed on the next line by hyphens. Viruses and Bees Although trying to cover everything about honey bee viruses would require writing a book, the publications are out

  11. Preliminary research on soil conditioner mediated citrus Huanglongbing mitigation in the field in Guangdong, China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB, yellow shoot disease) is devastating to citrus production worldwide. No completely effective management measure is currently available. In China, HLB management through nutrient applications was used in the past, and now has renewed interest. Therefore, soil conditioner (SC) effe...

  12. Effect of chemical compounds on the ‘Cadidatus Liberibacter asiaticus’ infected pomelo (Citrus maxima)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), also known as citrus greening, is one of the most destructive diseases affecting Rutaceae plants in many parts of the world. HLB is associated with three species of ‘Candidatus Liberibacter’ with ‘Ca. L. asiaticus’ (Las), being the most widely distributed in Thailand and Asia. T...

  13. Incidence and severity of huanglongbing and Candidatus Liberibacter asiaticus titer among field-infected citrus cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Incidence and severity of Huanglongbing (HLB) disease were assessed in April, 2010 among eight citrus cultivars representing diverse scion types growing in commercial groves in Florida’s Indian River region, an area with high incidence of HLB. Twenty trees of each cultivar were rated for visual HLB...

  14. 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...

  15. Radiation preservation of foods of plant origin. Part IV. Subtropical fruits: citrus, grapes, and avocados

    SciTech Connect

    Thomas, P.

    1986-01-01

    Current information on the use of ionizing radiation for improving the storage of subtropical fruits like citrus, grapes, and avocados is reviewed. The feasibility of applying radiation either alone or in combination with other physical or chemical treatments for the control of postharvest fungal diseases is considered. Irradiation effects on the physiology of the fruits as related to respiration, ethylene evolution, changes in major chemical constituents, and quality are discussed. The recent trends in the possible use of irradiation as an alternative treatment to chemical fumigants for disinfestation of citrus and avocados and the prospects for the future application of irradiation for preservation of some of these fruits are outlined. 128 references.

  16. 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.

  17. 7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...false Procedure for permitting growers to ship tree run citrus fruit. 905.149 Section 905.149...149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run citrus fruit. Tree run citrus fruit as...

  18. 7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...false Procedure for permitting growers to ship tree run citrus fruit. 905.149 Section 905.149...149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run citrus fruit. Tree run citrus fruit as...

  19. 7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...false Procedure for permitting growers to ship tree run citrus fruit. 905.149 Section 905.149...149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run citrus fruit. Tree run citrus fruit as...

  20. 7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...false Procedure for permitting growers to ship tree run citrus fruit. 905.149 Section 905.149...149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run citrus fruit. Tree run citrus fruit as...

  1. 7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...false Procedure for permitting growers to ship tree run citrus fruit. 905.149 Section 905.149...149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run citrus fruit. Tree run citrus fruit as...

  2. Physiological changes associated with senescence and abscission in mature citrus fruit induced by 5-chloro-3-

    E-print Network

    Burns, Jacqueline K.

    Physiological changes associated with senescence and abscission in mature citrus fruit induced by 5 K. Burns* Horticultural Sciences Department, Citrus Research and Education Center, University), a plant growth regulator that selectively promotes abscission in mature citrus fruit (Citrus sinensis

  3. 7 CFR 93.5 - Fees for citrus product analyses set by cooperative agreement.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Fees for citrus product analyses set by cooperative agreement...TESTING PROGRAMS PROCESSED FRUITS AND VEGETABLES Citrus Juices and Certain Citrus Products § 93.5 Fees for citrus product...

  4. 7 CFR 93.5 - Fees for citrus product analyses set by cooperative agreement.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Fees for citrus product analyses set by cooperative agreement...TESTING PROGRAMS PROCESSED FRUITS AND VEGETABLES Citrus Juices and Certain Citrus Products § 93.5 Fees for citrus product...

  5. 7 CFR 93.5 - Fees for citrus product analyses set by cooperative agreement.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Fees for citrus product analyses set by cooperative agreement...TESTING PROGRAMS PROCESSED FRUITS AND VEGETABLES Citrus Juices and Certain Citrus Products § 93.5 Fees for citrus product...

  6. 7 CFR 93.5 - Fees for citrus product analyses set by cooperative agreement.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Fees for citrus product analyses set by cooperative agreement...TESTING PROGRAMS PROCESSED FRUITS AND VEGETABLES Citrus Juices and Certain Citrus Products § 93.5 Fees for citrus product...

  7. 7 CFR 93.5 - Fees for citrus product analyses set by cooperative agreement.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Fees for citrus product analyses set by cooperative agreement...TESTING PROGRAMS PROCESSED FRUITS AND VEGETABLES Citrus Juices and Certain Citrus Products § 93.5 Fees for citrus product...

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

    PubMed

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

    2010-03-01

    Xylella fastidiosa causes a serious Pierce's disease (PD) in grapevine. Xylella fastidiosa cells from a PD strain were grown in a pure xylem fluid of a susceptible grapevine cultivar vs. xylem fluid from citrus, which is not a host for this strain of X. fastidiosa. When grown in grapevine xylem fluid, cells of the PD strain formed clumps and biofilm formed to a greater extent than in citrus xylem fluid, although the PD strain did grow in xylem fluid of three citrus varieties. The differential expression of selected genes of a PD X. fastidiosa strain cultured in the two xylem fluids was analyzed using a DNA macroarray. Compared with citrus xylem fluid, grapevine xylem fluid stimulated the expression of X. fastidiosa genes involved in virulence regulation, such as gacA, algU, xrvA, and hsq, and also genes involved in the biogenesis of pili and twitching motility, such as fimT, pilI, pilU, and pilY1. Increased gene expression likely contributes to PD expression in grapevine, whereas citrus xylem fluid did not support or possibly suppressed the expression of these virulence genes. PMID:20070368

  9. 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

  10. Expression Profiling of Virulence and Pathogenicity Genes of Xanthomonas axonopodis pv. citri

    Microsoft Academic Search

    Gustavo Astua-Monge; Juliana Freitas-Astua; Gisele Bacocina; Juliana Roncoletta; Sergio A. Carvalho; Marcos A. Machado

    2005-01-01

    Citrus canker, caused by Xanthomonas axonopodis Starr & Garces emend. Vauterin et al. pv. citri (Hasse) Dye (syn. Xan- thomonas campestris pv. citri (Hasse)), is one of the most dev- astating citrus diseases in the world (44). Within the genus Xanthomonas, several genes have been found associated with pathogenicity and virulence. Of these genes, the avr (avirulence), rpf (named for

  11. Consumer demand patterns for fresh citrus and citrus products in Houston, Texas

    E-print Network

    Stack, Thomas N

    1951-01-01

    CONSUME'R DLMAND PATTIJUlS FOR FRESH CITRUS AND CITRUS PRODUCTS LN HOUSTON~ TEXAS THOMAS N. STACK I A Thesis Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements... for the degree of MASTFR OF SCIENCE MAJOR SUBJECT: AGRICULTURAL ECONOMICS January 1951 COHSl&KR DE?AND PATTERNS FOR FEDASH CITRUS AND CITRUS PRODUCTS IN HOUSTON~ TEXAS THGHAS N. STACK Appeoved as to style and content by C of CaesLtttee kcknovledgement...

  12. Characterization of the Asian Citrus Psyllid Transcriptome.

    PubMed

    Reese, Justin; Christenson, Matthew K; Leng, Nan; Saha, Surya; Cantarel, Brandi; Lindeberg, Magdalen; Tamborindeguy, Cecilia; Maccarthy, Justin; Weaver, Daniel; Trease, Andrew J; Steven V, Ready; 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

  13. 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

  14. A new detached-leaf assay to test the inoculativity of psyllids with Candidatus Liberibacter asiaticus associated with huanglongbing disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To test the inoculativity of the Asian citrus psyllid (ACP) with Candidatus Liberibacter asiaticus (Las), associated with the Huanglongbing (HLB) or citrus greening disease, psyllids are usually fed singly or in small groups on citrus seedlings and these assayed by polymerase chain reaction (PCR) 3-...

  15. Postharvest decay control of citrus fruit by preharvest pyrimethanil spray.

    PubMed

    D'Aquino, S; Angioni, A; Suming, D; Palma, A; Schirra, M

    2013-01-01

    Preharvest infections or conidia load on fruit surface by Penicillium digitatum, P. italicum, Alternaria citri and other filamentous fungi can cause important postharvest losses of citrus fruit. Reduction in pruning frequency occurred in the last decade together with un-picked yield that eventually rots on the trees have increased the risk of postharvest decay especially when environmental conditions at picking time are favourable to pathogens' development. Sanitation procedures in the packinghouses, alternate use of postharvest fungicides with different modes of action, along with fungicide application before harvest could be an effective approach to minimize postharvest decay in citrus fruit. The present study investigated the effectiveness of a preharvest treatment with pyrimethanil (PYR), a broad spectrum fungicide, recently registered in different citrus-producing countries for postharvest treatments of citrus fruit and widely used worldwide as a preharvest treatment to control various diseases in different crops. PYR (750 mg/L) was sprayed by a hand-back sprayer at run-off on 'Fremont' mandarins. The day after the treatment, half of the trees were sprayed with a 10(4) conidial suspension of P. digitatum at run-off. Fruit were harvested following 2 or 4 weeks from treatments. Sound or either wounded 2-mm-deep and 2-mm-wide or superficial wound-scratched fruit were stored at 20 degrees C and 90% RH and inspected for decay after 1, 2 or 3 weeks of storage. In fruit harvested after 2 weeks from field treatment, PYR remarkably reduced decay development during two weeks of storage in sound fruit and in wound-scratched fruit and was fairly effective even after 4 weeks from treatment, but was ineffective in fruit wounded 2 mm deep and 2 mm wide. PYR was also effective in reducing preharvest decay incited by P. digitatum, P. italicum and Botrytis cinerea, but not by other pathogens. Results show that preharvest treatment with PYR could be a feasible approach to reduce postharvest chemical control of decay of citrus fruit. PMID:25145229

  16. Biology and management of Asian citrus psyllid, vector of the huanglongbing pathogens.

    PubMed

    Grafton-Cardwell, Elizabeth E; Stelinski, Lukasz L; Stansly, Philip A

    2013-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the most important pest of citrus worldwide because it serves as a vector of "Candidatus Liberibacter" species (Alphaproteobacteria) that cause huanglongbing (citrus greening disease). All commercially cultivated citrus is susceptible and varieties tolerant to disease expression are not yet available. Onset of disease occurs following a long latent period after inoculation, and thus the pathogen can spread widely prior to detection. Detection of the pathogen in Brazil in 2004 and Florida in 2005 catalyzed a significant increase in research on D. citri biology. Chemical control is the primary management strategy currently employed, but recently documented decreases in susceptibility of D. citri to several insecticides illustrate the need for more sustainable tools. Herein, we discuss recent advances in the understanding of D. citri biology and behavior, pathogen transmission biology, biological control, and chemical control with respect to "Candidatus Liberibacter asiaticus." Our goal is to point toward integrated and biologically relevant management of this pathosystem. PMID:23317046

  17. Isolation and characterization of an Isaria fumosorosea isolate infecting the Asian citrus psyllid in Florida.

    PubMed

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

    2008-09-01

    A fungal pathogen that killed adult Diaphorina citri Kuwayama (Asian citrus psyllid) (Hemiptera: Psyllidae) in Florida citrus groves during the fall of 2005 was identified and characterized. Investigation of this pathogen is important because D. citri vectors citrus greening disease (Huanglongbing), which was reported in Florida in 2005. The morphological and genetic data generated herein support identification of the fungus as Isaria fumosorosea Wize (Ifr) (=Paecilomyces fumosoroseus) (Hypocreales: Cordycipitaceae) from the Asian citrus psyllid (Ifr AsCP). Koch's postulates were fulfilled after the fungus was isolated in vitro and transmitted to healthy psyllids, which then exhibited a diseased-phenotype similar to that observed in the field. Both in vitro growth characteristics and two Ifr AsCP-specific molecular markers discriminated the psyllid pathogen from another local Ifr isolate, Ifr 97 Apopka. These molecular markers will be useful to track the dynamics of this disease in D. citri populations. The potential for utilizing Ifr to complement existing psyllid pest management strategies is discussed. PMID:18433768

  18. Analysis of 13000 unique Citrus clusters associated with fruit quality, production and salinity tolerance

    PubMed Central

    Terol, Javier; Conesa, Ana; Colmenero, Jose M; Cercos, Manuel; Tadeo, Francisco; Agustí, Javier; Alós, Enriqueta; Andres, Fernando; Soler, Guillermo; Brumos, Javier; Iglesias, Domingo J; Götz, Stefan; Legaz, Francisco; Argout, Xavier; Courtois, Brigitte; Ollitrault, Patrick; Dossat, Carole; Wincker, Patrick; Morillon, Raphael; Talon, Manuel

    2007-01-01

    Background Improvement of Citrus, the most economically important fruit crop in the world, is extremely slow and inherently costly because of the long-term nature of tree breeding and an unusual combination of reproductive characteristics. Aside from disease resistance, major commercial traits in Citrus are improved fruit quality, higher yield and tolerance to environmental stresses, especially salinity. Results A normalized full length and 9 standard cDNA libraries were generated, representing particular treatments and tissues from selected varieties (Citrus clementina and C. sinensis) and rootstocks (C. reshni, and C. sinenis × Poncirus trifoliata) differing in fruit quality, resistance to abscission, and tolerance to salinity. The goal of this work was to provide a large expressed sequence tag (EST) collection enriched with transcripts related to these well appreciated agronomical traits. Towards this end, more than 54000 ESTs derived from these libraries were analyzed and annotated. Assembly of 52626 useful sequences generated 15664 putative transcription units distributed in 7120 contigs, and 8544 singletons. BLAST annotation produced significant hits for more than 80% of the hypothetical transcription units and suggested that 647 of these might be Citrus specific unigenes. The unigene set, composed of ~13000 putative different transcripts, including more than 5000 novel Citrus genes, was assigned with putative functions based on similarity, GO annotations and protein domains Conclusion Comparative genomics with Arabidopsis revealed the presence of putative conserved orthologs and single copy genes in Citrus and also the occurrence of both gene duplication events and increased number of genes for specific pathways. In addition, phylogenetic analysis performed on the ammonium transporter family and glycosyl transferase family 20 suggested the existence of Citrus paralogs. Analysis of the Citrus gene space showed that the most important metabolic pathways known to affect fruit quality were represented in the unigene set. Overall, the similarity analyses indicated that the sequences of the genes belonging to these varieties and rootstocks were essentially identical, suggesting that the differential behaviour of these species cannot be attributed to major sequence divergences. This Citrus EST assembly contributes both crucial information to discover genes of agronomical interest and tools for genetic and genomic analyses, such as the development of new markers and microarrays. PMID:17254327

  19. Differential responses of Central American and Mexican pine species and Pinus radiata to infection by the pitch canker fungus

    Microsoft Academic Search

    G. R. Hodge; W. S. Dvorak

    2000-01-01

    Seedlings from a wide array of 23 species, varieties,and geographic races were screened for resistance topitch canker using artificial inoculation in agreenhouse. Seed to represent these taxa weregenerally collected in natural stands. In addition,seedlings from 79 families of P. radiata fromcommercial populations from Chile and New Zealand werescreened in a separate experiment. There was littlevariation in resistance among the commercial

  20. A new Real-time PCR-method for the quantification of the Pine Pitch Canker fungus Fusarium circinatum.

    E-print Network

    California at Berkeley, University of

    enhanced by airborne spores, insect vectors and the movement of infected plant material. Detection of spore numbers from environmental samples and (iii) to determine the mating type of the fungal isolates brown flagging of Pine Pitch Canker WORKING SCHEME suspend spores in 20 ml 4X TE-buffer 65ºC DNA