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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    PubMed Central

    Hao, Guixia; Stover, Ed; Gupta, Goutam

    2016-01-01

    Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the US citrus industry. There are no proven strategies to eliminate HLB disease and no cultivar has been identified with strong HLB resistance. Citrus canker is also an economically important disease associated with a bacterial pathogen (Xanthomonas citri). In this study, we characterized endogenous citrus thionins and investigated their expression in different citrus tissues. Since no HLB-resistant citrus cultivars have been identified, we attempted to develop citrus resistant to both HLB and citrus canker through overexpression of a modified plant thionin. To improve effectiveness for disease resistance, we modified and synthesized the sequence encoding a plant thionin and cloned into the binary vector pBinPlus/ARS. The construct was then introduced into Agrobacterium strain EHA105 for citrus transformation. Transgenic Carrizo plants expressing the modified plant thionin were generated by Agrobacterium-mediated transformation. Successful transformation and transgene gene expression was confirmed by molecular analysis. Transgenic Carrizo plants expressing the modified thionin gene were challenged with X. citri 3213 at a range of concentrations, and a significant reduction in canker symptoms and a decrease in bacterial growth were demonstrated compared to nontransgenic plants. Furthermore, the transgenic citrus plants were challenged with HLB via graft inoculation. Our results showed significant Las titer reduction in roots of transgenic Carrizo compared with control plants and reduced scion Las titer 12 months after graft inoculation. These data provide promise for engineering citrus disease resistance against HLB and canker. PMID:27499757

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

    PubMed

    Hao, Guixia; Stover, Ed; Gupta, Goutam

    2016-01-01

    Huanglongbing (HLB or citrus greening disease) caused by Candidatus Liberibacter asiaticus (Las) is a great threat to the US citrus industry. There are no proven strategies to eliminate HLB disease and no cultivar has been identified with strong HLB resistance. Citrus canker is also an economically important disease associated with a bacterial pathogen (Xanthomonas citri). In this study, we characterized endogenous citrus thionins and investigated their expression in different citrus tissues. Since no HLB-resistant citrus cultivars have been identified, we attempted to develop citrus resistant to both HLB and citrus canker through overexpression of a modified plant thionin. To improve effectiveness for disease resistance, we modified and synthesized the sequence encoding a plant thionin and cloned into the binary vector pBinPlus/ARS. The construct was then introduced into Agrobacterium strain EHA105 for citrus transformation. Transgenic Carrizo plants expressing the modified plant thionin were generated by Agrobacterium-mediated transformation. Successful transformation and transgene gene expression was confirmed by molecular analysis. Transgenic Carrizo plants expressing the modified thionin gene were challenged with X. citri 3213 at a range of concentrations, and a significant reduction in canker symptoms and a decrease in bacterial growth were demonstrated compared to nontransgenic plants. Furthermore, the transgenic citrus plants were challenged with HLB via graft inoculation. Our results showed significant Las titer reduction in roots of transgenic Carrizo compared with control plants and reduced scion Las titer 12 months after graft inoculation. These data provide promise for engineering citrus disease resistance against HLB and canker. PMID:27499757

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  8. 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

  9. 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...

  10. Integrated Management of Citrus Canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  11. A comparison of culture and bioassay for detecting citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) causes serious crop losses in tropical and subtropical citrus production regions. Detecting Xcc is important for quarantine purposes, research and disease management. Although PCR methods are available for detecting and quantifying viable bacteria,...

  12. 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...

  13. 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

  14. 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

  15. 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 ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. 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

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

    PubMed

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

    2016-01-10

    Citrus canker and Huanglongbing (HLB) are citrus diseases that represent a serious threat to the citrus production worldwide and may cause large economic losses. In this work, we combined fluorescence imaging spectroscopy (FIS) and a machine learning technique to discriminate between these diseases and other ordinary citrus conditions that may be present at citrus orchards, such as citrus scab and zinc deficiency. Our classification results are highly accurate when discriminating citrus canker from citrus scab (97.8%), and HLB from zinc deficiency (95%). These results show that it is possible to accurately identify citrus diseases that present similar symptoms. PMID:26835778

  19. 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...

  20. 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...

  1. 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...

  2. 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. ...

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

    PubMed

    Khodakaramian, G; Swings, J

    2011-06-01

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

  4. 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...

  5. Detecting citrus canker by hyperspectral reflectance imaging and PCA-based image classification method

    NASA Astrophysics Data System (ADS)

    Qin, Jianwei; Burks, Thomas F.; Kim, Moon S.; Chao, Kuanglin; Ritenour, Mark A.

    2008-04-01

    Citrus canker is one of the most devastating diseases that threaten citrus crops. Technologies that can efficiently identify citrus canker would assure fruit quality and safety and enhance the competitiveness and profitability of the citrus industry. This research was aimed to investigate the potential of using hyperspectral imaging technique for detecting canker lesions on citrus fruit. A portable hyperspectral imaging system consisting of an automatic sample handling unit, a light source, and a hyperspectral imaging unit was developed for citrus canker detection. The imaging system was used to acquire reflectance images from citrus samples in the wavelength range between 400 nm and 900 nm. Ruby Red grapefruits with normal and various diseased skin conditions including canker, copper burn, greasy spot, wind scar, cake melanose, and specular melanose were tested. Hyperspectral reflectance images were analyzed using principal component analysis (PCA) to compress the 3-D hyperspectral image data and extract useful image features that could be used to discriminate cankerous samples from normal and other diseased samples. Image processing and classification algorithms were developed based upon the transformed images of PCA. The overall accuracy for canker detection was 92.7%. This research demonstrated that hyperspectral imaging technique could be used for discriminating citrus canker from other confounding diseases.

  6. Reasons for inconsistent citrus canker control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crop losses from citrus canker in 2014 for Hamlin due to premature fruit drop, or for grapefruit from unacceptable severity of fruit lesions, were highly variable due to periodic rains that in certain locations were coincident with grapefruit flushes in February-March or with early Hamlin fruit deve...

  7. 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...

  8. 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...

  9. 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...

  10. Incidence and severity of Asiatic citrus canker on citrus and citrus–related germplasm in a Florida field planting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas citri ssp. citri (Hasse), is the causal agent of Asiatic citrus canker (ACC), a commercially important disease in Florida citrus, as well as in many other regions. In this study we evaluated occurrence of foliar lesions from ACC on progenies of 94 seed-source genotypes (hereafter called ...

  11. 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...

  12. 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...

  13. 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...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

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

  15. Detection of fluorescent compounds in citrus leaf cankers

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  16. 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...

  17. 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

    ... Collection; Citrus Canker; Interstate Movement of Regulated Nursery Stock and Fruit From Quarantined Areas... nursery stock and fruit from quarantined areas to prevent the spread of citrus canker. DATES: We will... from citrus canker quarantined areas, contact Ms. Lynn Evans-Goldner, National Policy Manager, PHP,...

  18. 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...

  19. 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...

  20. 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...

  1. Effect of the duration of inoculum exposure on development of citrus canker symptoms on seedlings of Swingle citrumelo

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) is one of the most serious diseases citrus in Florida, and elsewhere in the world. The disease causes yield loss and some fresh fruit trade restrictions may apply. Cultural management techniques such as windbreaks may work by not only reducing wind...

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

    Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is one of the most important bacterial diseases of citrus. Because citrus canker is not found in many countries including European Union and Australia, Xcc is strictly regulated in order to prevent its spread. In this study, the effects of X-irradiation on Xcc growth either in the suspension or on the surface of citrus fruits were investigated. The suspension containing 1×107 cfu/ml of Xcc was irradiated with different absorbed doses of X-irradiation ranging from 50 to 400 Gy. The results showed that Xcc was fully dead at 400 Gy of X-irradiation. To determine the effect of X-irradiation on quarantine, the Xcc-inoculated citrus fruits were irradiated with different X-ray doses at which Xcc was completely inhibited by an irradiation dose of 250 Gy. The D10 value for Xcc on citrus fruits was found to be 97 Gy, indicating the possibility of direct application on citrus quarantine without any side sterilizer. Beside, presence of Xcc on the surface of asymptomatic citrus fruits obtained from citrus canker-infected orchards was noted. It indicated that the exporting citrus fruits need any treatment so that Xcc on the citrus fruits should be completely eliminated. Based on these results, ionizing radiation can be considered as an alternative method of eradicating Xcc for export of citrus fruits. PMID:26672670

  4. Hyperspectral reflectance imaging for detecting citrus canker based on dual-band ratio image classification method

    NASA Astrophysics Data System (ADS)

    Li, Jiangbo; Rao, Xiuqin; Guo, Junxian; Ying, Yibin

    2010-10-01

    Citrus are one of the major fruit produced in China. Most of this production is exported to Europe for fresh consumption, where consumers increasingly demand best quality. Citrus canker is one of the most devastating diseases that threaten peel of most commercial citrus varieties. The aim of this research was to investigate the potential of using hyperspectral imaging technique for detecting canker lesions on citrus fruit. Navel oranges with cankerous, normal and various common diseased skin conditions including wind scar, thrips scarring, scale insect, dehiscent fruit, phytotoxicity, heterochromatic stripe, and insect damage were studied. The imaging system (400-1000 nm) was established to acquire reflectance images from samples. Region of interest (ROI) spectral feature of various diseased peel areas was analyzed and characteristic wavebands (630, 685, and 720 nm) were extracted. The dual-band reflectance ratio (such as Q720/685) algorithm was performed on the hyperspectral images of navel oranges for differentiating canker from normal fruit skin and other surface diseases. The overall classification success rate was 96.84% regardless of the presence of other confounding diseases. The presented processing approach overcame the presence of stem/navel on navel oranges that typically has been a problematic source for false positives in the detection of defects. Because of the limited sample size, delineation of an optimal detection scheme is beyond the scope of the current study. However, the results showed that two-band ratio (Q685/630) along with the use of a simple threshold value segmentation method for discriminating canker on navel oranges from other peel diseases may be feasible.

  5. 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

  6. 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

  7. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  9. 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

  10. 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

  11. 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 H₂O₂ 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 β-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

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

    PubMed

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

    2015-06-01

    The bacterial agent of citrus canker disease (Xanthomonas citri ssp. citri, Xcc) has caused tremendous economic losses to the citrus industry around the world. Pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) is important to plant immunity. In this study, we compared the defence responses of citrus canker-resistant and citrus canker-susceptible genotypes to the Xcc-derived PAMP flg22 (Xflg22) by analysing the expression of 20 citrus defence-associated genes. We showed that, in the most resistant genotype, 'Nagami' kumquat, there was significant induction of several defence genes (EDS1, NDR1, PBS1, RAR1, SGT1, PAL1, NPR2 and NPR3) as early as 6 h and up to 72 h after Xflg22 treatment. At the other end of the spectrum, highly susceptible 'Duncan' grapefruit showed no induction of the same defence genes, even 120 h after treatment. Citrus genotypes with partial levels of resistance showed intermediate levels of transcriptional reprogramming that correlated with their resistance level. Xflg22 also triggered a rapid oxidative burst in all genotypes which was higher and accompanied by the induction of PTI marker genes (WRKY22 and GST1) only in the more resistant genotypes. Pretreatment with Xflg22 prior to Xcc inoculation inhibited bacterial growth in kumquat, but not in grapefruit. A flagellin-deficient Xcc strain (XccΔfliC) showed greater growth increase relative to wild-type Xcc in kumquat than in grapefruit. Taken together, our results indicate that Xflg22 initiates strong PTI in canker-resistant genotypes, but not in susceptible ones, and that a robust induction of PTI is an important component of citrus resistance to canker. PMID:25231217

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

    PubMed

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

    2015-05-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  15. 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...

  16. A survey of survival and activity of citrus canker lesion populations on foliage, fruit and shoots in a Florida grapefruit orchard in 2009 and 2010

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri (Xcc)) can infect several species of citrus. The disease can develop on the leaves, shoots and fruit, causing erumpent lesions, that on fruit precludes sale to the fresh market. We assessed lesion activity in orchard-grown grapefruit to provide informa...

  17. 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

  18. The Efficacy and Underlying Mechanism of Sulfone Derivatives Containing 1,3,4-oxadiazole on Citrus Canker.

    PubMed

    Li, Pei; Ma, Yuhua; Zhou, Junliang; Luo, Hui; Yan, Jiawen; Mao, Yongya; Wang, Zhuang

    2015-01-01

    The objectives of the current study were to isolate and identify the pathogen responsible for citrus canker and investigate the efficacy of sulfone derivatives containing 1,3,4-oxadiazole moiety on controlling citrus canker caused by Xanthomonas citri subsp. citri (Xcc) under in vitro and field conditions. In an in vitro study, we tested eight sulfone derivatives against Xcc and the results demonstrated that compound 3 exhibited the best antibacterial activity against Xcc, with a half-maximal effective concentration (EC50) value of 1.23 μg/mL, which was even better than those of commercial bactericides Kocide 3000 (58.21 μg/mL) and Thiodiazole copper (77.04 μg/mL), respectively. Meanwhile, under field experiments, compound 3 treatments demonstrated the highest ability to reduce the disease of citrus canker in leaves and fruits in two different places relative to an untreated control as well as the commercial bactericides Kocide 3000 and Thiodiazole copper. Meanwhile, compound 3 could stimulate the increase in peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia lyase (PAL) activities in the navel orange leaves, causing marked enhancement of plant resistance against citrus canker. Moreover, compound 3 could damage the cell membranes, destruct the biofilm formation, inhibit the production of extracellular polysaccharide (EPS), and affect the cell membrane permeability to restrain the growth of the bacteria. PMID:26247929

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

    PubMed

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

    2006-05-01

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

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

    PubMed

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

    2015-10-01

    Understanding the evolutionary history and potential of bacterial pathogens is critical to prevent the emergence of new infectious bacterial diseases. Xanthomonas axonopodis subsp. citri (Xac) (synonym X. citri subsp. citri), which causes citrus canker, is one of the hardest-fought plant bacterial pathogens in US history. Here, we sequenced 21 Xac strains (14 XacA, 3 XacA* and 4 XacA(w)) with different host ranges from North America and Asia and conducted comparative genomic and evolutionary analyses. Our analyses suggest that acquisition of beneficial genes and loss of detrimental genes most likely allowed XacA to infect a broader range of hosts as compared with XacA(w) and XacA*. Recombination was found to have occurred frequently on the relative ancient branches, but rarely on the young branches of the clonal genealogy. The ratio of recombination/mutation ρ/θ was 0.0790±0.0005, implying that the Xac population was clonal in structure. Positive selection has affected 14% (395 out of 2822) of core genes of the citrus canker-causing Xanthomonas. The genes affected are enriched in 'carbohydrate transport and metabolism' and 'DNA replication, recombination and repair' genes (P<0.05). Many genes related to virulence, especially genes involved in the type III secretion system and effectors, are affected by positive selection, further highlighting the contribution of positive selection to the evolution of citrus canker-causing Xanthomonas. Our results suggest that both metabolism and virulence genes provide advantages to endow XacA with higher virulence and a wider host range. Our analysis advances our understanding of the genomic basis of specialization by positive selection in bacterial evolution. PMID:25689023

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  2. DNA polymorphisms and biocontrol of Bacillus antagonistic to citrus bacterial canker with indication of the interference of phyllosphere biofilms.

    PubMed

    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

  3. Rapid and sensitive detection of Citrus Bacterial Canker by loop-mediated isothermal amplification combined with simple visual evaluation methods

    PubMed Central

    2010-01-01

    Background Citrus Bacterial Canker (CBC) is a major, highly contagious disease of citrus plants present in many countries in Asia, Africa and America, but not in the Mediterranean area. There are three types of Citrus Bacterial Canker, named A, B, and C that have different genotypes and posses variation in host range within citrus species. The causative agent for type A CBC is Xanthomonas citri subsp. citri, while Xanthomonas fuscans subsp. aurantifolii, strain B causes type B CBC and Xanthomonas fuscans subsp. aurantifolii strain C causes CBC type C. The early and accurate identification of those bacteria is essential for the protection of the citrus industry. Detection methods based on bacterial isolation, antibodies or polymerase chain reaction (PCR) have been developed previously; however, these approaches may be time consuming, laborious and, in the case of PCR, it requires expensive laboratory equipment. Loop-mediated isothermal amplification (LAMP), which is a novel isothermal DNA amplification technique, is sensitive, specific, fast and requires no specialized laboratory equipment. Results A loop-mediated isothermal amplification assay for the diagnosis of Citrus Bacterial Canker (CBC-LAMP) was developed and evaluated. DNA samples were obtained from infected plants or cultured bacteria. A typical ladder-like pattern on gel electrophoresis was observed in all positive samples in contrast to the negative controls. In addition, amplification products were detected by visual inspection using SYBRGreen and using a lateral flow dipstick, eliminating the need for gel electrophoresis. The sensitivity and specificity of the assay were evaluated in different conditions and using several sample sources which included purified DNA, bacterium culture and infected plant tissue. The sensitivity of the CBC-LAMP was 10 fg of pure Xcc DNA, 5 CFU in culture samples and 18 CFU in samples of infected plant tissue. No cross reaction was observed with DNA of other phytopathogenic

  4. 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...

  5. Efficacy of Cankerguard® Sprays for Effective Decontamination of Citrus Canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (Xanthomonas citri subsp. citri, Xcc) is endemic in Florida. We used grapefruit leaf surfaces to explore the efficacy of the personnel decontaminant Cankerguard® to kill inoculum. In three experiments plants in flush (leaves 3/4 expanded) were sprayed with inoculum (2x104-9x105 CFU/ml)...

  6. 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...

  7. 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...

  8. Research promises earlier warning for grapevine canker diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When it comes to detecting and treating vineyards for grapevine canker diseases (also called trunk diseases), like Botryosphaeria dieback (Bot canker), Esca, Eutypa dieback and Phomopsis dieback, the earlier the better, says plant pathologist Kendra Baumgartner, with the USDA’s Agricultural Research...

  9. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  12. Modifications of Xanthomonas axonopodis pv. citri lipopolysaccharide affect the basal response and the virulence process during citrus canker.

    PubMed

    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

  13. 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

  14. 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...

  15. 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

  16. 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...

  17. 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 ...

  18. Pruning for prevention and management of canker diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Trunk diseases (wood-canker diseases) threaten all California vineyards due to widespread distribution of the fungal pathogens. The infections are chronic and occur each year. Trunk diseases in mature vineyards reduce yields and increase management costs to the point where the vineyard is no longer ...

  19. Cercosporoid diseases of Citrus.

    PubMed

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

    2015-01-01

    Citrus leaves and fruits exhibiting disease symptoms ranging from greasy spot, yellow spot, small or large brown spot, black dot, and brown dot were sampled from Fujian, Guangdong, Guizhou, Hunan, Jiangxi, Yunnan, Zhejiang provinces and the Guangxi Zhuang Autonomous Region in China. In total 82 isolates representing various cercosporoid genera were isolated from these disease symptoms, which were supplemented with eight Citrus cercosporoid isolates collected from other countries. Based on a morphological and phylogenetic study using sequence data from the nuclear ribosomal DNA's ITS1-5.8S-ITS2 regions (ITS), and partial actin (act), β-tubulin (tub2), 28S nuclear ribosomal RNA (28S rDNA) and translation elongation factor 1-α (tef1) genes, these strains were placed in the following genera: Cercospora, Pallidocercospora, Passalora, Pseudocercospora, Verrucisporota and Zasmidium. All isolates tended to be sterile, except the Zasmidium isolates associated with citrus greasy spot-like symptoms, which subsequently were compared with phylogenetically similar isolates occurring on Citrus and other hosts elsewhere. From these results four Zasmidium species were recognized on Citrus, namely Z. indonesianum on Citrus in Indonesia, Z. fructicola and Z. fructigenum on Citrus in China and Z. citri-griseum, which appears to have a wide host range including Acacia, Citrus, Eucalyptus and Musa, as well as a global distribution. PMID:26432805

  20. 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

  1. Detection of mechanical and disease stresses in citrus plants by fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Belasque, J., Jr.; Gasparoto, M. C. G.; Marcassa, L. G.

    2008-04-01

    We have investigated the detection of mechanical and disease stresses in citrus plants (Citrus limonia [L.] Osbeck) using laser-induced fluorescence spectroscopy. Due to its economic importance we have chosen to investigate the citrus canker disease, which is caused by the Xanthomonas axonopodis pv. citri bacteria. Mechanical stress was also studied because it plays an important role in the plant's infection by such bacteria. A laser-induced fluorescence spectroscopy system, composed of a spectrometer and a 532 nm10 mW excitation laser was used to perform fluorescence spectroscopy. The ratio of two chlorophyll fluorescence bands allows us to detect and discriminate between mechanical and disease stresses. This ability to discriminate may have an important application in the field to detect citrus canker infected trees.

  2. 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...

  3. 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...

  4. Genetic Relationship among Worldwide Strains of Xanthomonas Causing Canker in Citrus Species and Design of New Primers for Their Identification by PCR†

    PubMed Central

    Cubero, J.; Graham, J. H.

    2002-01-01

    Partial sequence analysis of the ribosomal operon in Xanthomonas axonopodis allowed discrimination among strains causing the A, B, and C types of citrus bacterial canker (CBC) and quantification of the relationship of these organisms with other species and pathovars in the same genus. Sets of primers based on sequence differences in the internally transcribed spacer and on a sequence from the plasmid gene pthA involved in virulence were designed for specific identification of xanthomonads causing CBC diseases. The two sets were validated with a collection of Xanthomonas strains associated with citrus species. The primer set based on ribosomal sequences had a high level of specificity for X. axonopodis pv. citri, whereas the set based on the pthA gene was universal for all types of CBC organisms. Moreover, the relationships among worldwide Xanthomonas strains causing CBC were analyzed by amplification of repetitive sequences (enterobacterial repetitive intergenic consensus and BOX elements). Under specific conditions, pathotypes of these Xanthomonas strains could be discerned, and subgroups of the pathotypes were identified. Subgroups of strains were associated with certain geographic areas of the world, and on this basis the origin of type A strains introduced into Florida could be inferred. PMID:11872476

  5. Botryosphaeria Cane Canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the more serious cane canker diseases of thornless blackberry plants in the eastern U.S. is caused by Botryosphaeria dothidea. Cane canker disease is highly destructive, often killing canes and reducing fruit yields to uneconomic levels. Cankers generally develop around one or more buds on th...

  6. 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 ...

  7. 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

  8. 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

  9. Citrus stubborn disease (CSD)

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  10. Huanglongbing: a devastating disease of citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  11. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  13. Complete DNA Sequence of Pseudomonas syringae pv. actinidiae, the Causal Agent of Kiwifruit Canker Disease.

    PubMed

    Templeton, Matthew D; Warren, Benjamin A; Andersen, Mark T; Rikkerink, Erik H A; Fineran, Peter C

    2015-01-01

    Pseudomonas syringae pv. actinidiae is the causal agent of bacterial canker of kiwifruit, a disease that has rapidly spread worldwide. We have fully sequenced and assembled the chromosomal and plasmid DNA from P. syringae pv. actinidiae ICMP 18884 using the PacBio RS II platform. PMID:26383666

  14. 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

  15. Canker Sores

    MedlinePlus

    ... causes canker sores. Mouth injuries, stress, poor nutrition, food allergies and menstrual periods are some of the things that may increase your chances of getting a canker sore. Treatment How are canker sores treated? There is no cure for canker sores, but they usually go away ...

  16. Stubborn Disease of Citrus in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. Predisposition of citrus foliage to infection with Xanthomonas citri subsp. citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (caused by Xanthomonas citri subsp. citri, Xcc) is a serious disease of susceptible citrus in Florida and other citrus-growing areas of the world. The effect of leaf preconditioning as a route for entry of the bacteria is poorly characterized. A series of experiments were designed to i...

  18. Predisposition of citrus foliage to infection with Xanthomonas citri subsp. citri.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker (caused by Xanthomonas citri subsp. citri, Xcc) is a serious disease of susceptible citrus in Florida and other citrus-growing areas of the world. The specific effects of predisposing factors for bacterial penetration of leaves are poorly characterized. Experiments were designed to inv...

  19. Disadvantages of the Horsfall-Barratt Scale for estimating severity of citrus canker

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Direct visual estimation of disease severity to the nearest percent was compared to using the Horsfall-Barratt (H-B) scale. Data from a simulation model designed to sample two diseased populations were used to investigate the probability of the two methods to reject a null hypothesis (H0) using a t-...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  1. Levels of Candidatus Liberibacter asiaticus and Xanthomonas citri in diverse citrus genotypes and relevance to potential transmission from pollinations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diseases huanglongbing (HLB, associated with Candidatus Liberibacter asiaticus, CLas) and Asian citrus canker (ACC, caused by Xanthomonas citri, Xcc) are widespread in Florida and many other citrus-growing areas, presenting unprecedented challenges for citrus breeding. Since HLB and ACC weaken ...

  2. 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...

  3. Reduced susceptibility to Xanthomonas citri in transgenic citrus expressing the FLS2 receptor from Nicotiana benthamiana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Overexpression of plant pattern-recognition receptors (PRRs) by genetic engineering provides a novel approach to enhance plant immunity and broad-spectrum disease resistance. The citrus canker disease associated with Xanthomonas citri is one of the important diseases damaging citrus production world...

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

    PubMed

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

    2016-02-01

    Pseudomonas syringae pv. actinidiae causes bacterial canker disease in kiwifruit. Owing to the prohibition of agricultural antibiotic use in major kiwifruit-cultivating countries, alternative methods need to be developed to manage this disease. Bacteriophages are viruses that specifically infect target bacteria and have recently been reconsidered as potential biological control agents for bacterial pathogens owing to their specificity in terms of host range. In this study, we isolated bacteriophages against P. syringae pv. actinidiae from soils collected from kiwifruit orchards in Korea and selected seven bacteriophages for further characterization based on restriction enzyme digestion patterns of genomic DNA. Among the studied bacteriophages, two belong to the Myoviridae family and three belong to the Podoviridae family, based on morphology observed by transmission electron microscopy. The host range of the selected bacteriophages was confirmed using 18 strains of P. syringae pv. actinidiae, including the Psa2 and Psa3 groups, and some were also effective against other P. syringae pathovars. Lytic activity of the selected bacteriophages was sustained in vitro until 80 h, and their activity remained stable up to 50°C, at pH 11, and under UV-B light. These results indicate that the isolated bacteriophages are specific to P. syringae species and are resistant to various environmental factors, implying their potential use in control of bacterial canker disease in kiwifruits. PMID:26628254

  5. 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...

  6. Pest management practices aimed at curtailing citrus huanglongbing disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a devastating, insect-vectored disease of citrus sometimes referred to as citrus greening disease and putatively caused by phloem-limited bacteria within the genus Candidatus Liberibacter. Citrus trees infected by this disease decline in productivity; produce misshapen, inedib...

  7. 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...

  8. 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...

  9. Biological Indexing of Graft Transmissible Diseases of Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  10. 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...

  11. 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...

  12. 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...

  13. Canker Sores

    MedlinePlus

    ... cycle . Some research suggests that using products containing sodium lauryl sulfate (SLS) can be associated with canker sores. SLS ... with toothpastes and mouthwashes that don't contain sodium lauryl sulfate. And avoid brushing the sore itself with a ...

  14. 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

  15. Bismerthiazol inhibits Xanthomonas citri subsp. citri growth and induces differential expression of citrus defense-related genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker, caused by Xanthomonas citri ssp. citri (Xcc), is a serious disease and causes substantial economic losses to the citrus industry worldwide. The bactericide, bismerthiazol, has been widely used to control rice bacterial blight (Xanthomonas oryzae pv. oryzae). In this paper, we demonstr...

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

    PubMed Central

    Westbrook, Anthony; Woeste, Keith

    2016-01-01

    Geosmithia morbida is a filamentous ascomycete that causes thousand cankers disease in the eastern black walnut tree. This pathogen is commonly found in the western U.S.; however, recently the disease was also detected in several eastern states where the black walnut lumber industry is concentrated. G. morbida is one of two known phytopathogens within the genus Geosmithia, and it is vectored into the host tree via the walnut twig beetle. We present the first de novo draft genome of G. morbida. It is 26.5 Mbp in length and contains less than 1% repetitive elements. The genome possesses an estimated 6,273 genes, 277 of which are predicted to encode proteins with unknown functions. Approximately 31.5% of the proteins in G. morbida are homologous to proteins involved in pathogenicity, and 5.6% of the proteins contain signal peptides that indicate these proteins are secreted. Several studies have investigated the evolution of pathogenicity in pathogens of agricultural crops; forest fungal pathogens are often neglected because research efforts are focused on food crops. G. morbida is one of the few tree phytopathogens to be sequenced, assembled and annotated. The first draft genome of G. morbida serves as a valuable tool for comprehending the underlying molecular and evolutionary mechanisms behind pathogenesis within the Geosmithia genus. PMID:27168971

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

    PubMed

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

    2016-01-01

    Geosmithia morbida is a filamentous ascomycete that causes thousand cankers disease in the eastern black walnut tree. This pathogen is commonly found in the western U.S.; however, recently the disease was also detected in several eastern states where the black walnut lumber industry is concentrated. G. morbida is one of two known phytopathogens within the genus Geosmithia, and it is vectored into the host tree via the walnut twig beetle. We present the first de novo draft genome of G. morbida. It is 26.5 Mbp in length and contains less than 1% repetitive elements. The genome possesses an estimated 6,273 genes, 277 of which are predicted to encode proteins with unknown functions. Approximately 31.5% of the proteins in G. morbida are homologous to proteins involved in pathogenicity, and 5.6% of the proteins contain signal peptides that indicate these proteins are secreted. Several studies have investigated the evolution of pathogenicity in pathogens of agricultural crops; forest fungal pathogens are often neglected because research efforts are focused on food crops. G. morbida is one of the few tree phytopathogens to be sequenced, assembled and annotated. The first draft genome of G. morbida serves as a valuable tool for comprehending the underlying molecular and evolutionary mechanisms behind pathogenesis within the Geosmithia genus. PMID:27168971

  18. 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 ...

  19. Canker sore

    MedlinePlus

    ... most cases, the canker sores go away without treatment. Try not to eat hot or spicy foods, which can cause pain. Use over-the-counter medicines that ease pain in the area. Rinse your mouth with salt water or mild, over-the-counter mouthwashes. (DO NOT ...

  20. Quambalaria species, including Q. coyrecup sp. nov., implicated in canker and shoot blight diseases causing decline of Corymbia species in the southwest of Western Australia.

    PubMed

    Paap, Trudy; Burgess, Treena I; McComb, Jennifer A; Shearer, Bryan L; St J Hardy, Giles E

    2008-01-01

    A severe canker disease has been causing decline and death of Corymbia calophylla in the southwest of Western Australia (WA) for some years, but the causal agent has never been investigated. However, there have been historical reports dating back to the 1920s of a canker disease of amenity planted C. ficifolia caused by 'Sporotrichum destructor', though the description and Latin diagnosis were never published. It has been suggested that there may be links between this species and the genus Quambalaria, a group containing leaf and shoot pathogens of species of Eucalyptus and Corymbia. The aim of this study was to investigate the identity of the pathogen historically attributed to canker disease of C. ficifolia, determine whether this pathogen is responsible for the current epidemic of C. calophylla canker, and whether it is synonymous with Quambalaria. Surveys examined the range of Quambalaria spp. on Corymbia spp. endemic to southwest WA. Their phylogenetic relationship to Q. cyanescens, Q. eucalypti, and Q. pitereka was examined using rLSU and ITS sequence data. Morphological characters were also compared. Sequences confirmed that Q. cyanescens and Q. pitereka are present in southwest WA, with the latter associated with leaf and shoot disease. A third group isolated from cankers represent a new species of Quambalaria. Comparisons of disease symptoms and conidiogenesis indicate this species is synonymous with 'S. destructor'. The species is formally described here as Q. coyrecup sp. nov. PMID:18222081

  1. 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

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

    DOEpatents

    Cary; R. Bruce; Stubben, Christopher J.

    2011-03-22

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

  3. 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

    ... Information Collection; Citrus Canker; Interstate Movement of Regulated Nursery Stock and Fruit from... nursery stock and fruit from quarantined areas to prevent the spread of citrus canker and to request an... regulated nursery stock and fruit from quarantined areas to prevent the spread of citrus canker, contact...

  4. Two novel Fusarium species that cause canker disease of Sichuan pepper (Zanthoxylum bungeanum Maxim.) in northern China form a novel clade with F. torreyae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Canker disease of Sichuan pepper (Zanthoxylum bungeanum) has caused a decline in the production of this economically important spice in northern China over the past twenty-five years. To identify the etiological agent, 38 fungal strains were isolated from symptomatic tissues from trees in five provi...

  5. Comparison of different detection methods for citrus greening disease based on airborne multispectral and hyperspectral imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus greening or Huanglongbing (HLB) is a devastating disease spread in many citrus groves since first found in 2005 in Florida. Multispectral (MS) and hyperspectral (HS) airborne images of citrus groves in Florida were taken to detect citrus greening infected trees in 2007 and 2010. Ground truthi...

  6. 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...

  7. 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

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

    PubMed

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

    2016-02-01

    Overexpression of plant pattern-recognition receptors by genetic engineering provides a novel approach to enhance plant immunity and broad-spectrum disease resistance. Citrus canker disease associated with Xanthomonas citri is one of the most important diseases damaging citrus production worldwide. In this study, we cloned the FLS2 gene from Nicotiana benthamiana cDNA and inserted it into the binary vector pBinPlus/ARS to transform Hamlin sweet orange and Carrizo citrange. Transgene presence was confirmed by polymerase chain reaction (PCR) and gene expression of NbFLS2 was compared by reverse transcription quantitative PCR. Reactive oxygen species (ROS) production in response to flg22Xcc was detected in transgenic Hamlin but not in nontransformed controls. Low or no ROS production was detected from nontransformed Hamlin seedlings challenged with flg22Xcc. Transgenic plants highly expressing NbFLS2 were selected and were evaluated for resistance to canker incited by X. citri 3213. Our results showed that the integration and expression of the NbFLS2 gene in citrus can increase canker resistance and defense-associated gene expression when challenged with X. citri. These results suggest that canker-susceptible Citrus genotypes lack strong basal defense induced by X. citri flagellin and the resistance of these genotypes can be enhanced by transgenic expression of the flagellin receptor from a resistant species. PMID:26554734

  9. 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

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

    PubMed

    Boina, Dhana Raj; Bloomquist, Jeffrey R

    2015-06-01

    By 2014, huanglongbing (HLB), the most destructive disease of citrus, and its insect vector, the Asian citrus psyllid (ACP), Diaphorina citri (Kuwayama), became established in all major citrus-growing regions of the world, including the United States, with the exception of California. At present, application of insecticides is the most widely followed option for reducing ACP populations, while application of antibiotics for suppressing HLB disease/symptoms is being practiced in some citrus-growing regions. Application of insecticides during the dormant winter season, along with cultivation of HLB-free seedlings and early detection and removal of symptomatic and asymptomatic trees, has been very effective in managing ACP. Area-wide management of ACP by application of insecticides at low volume in large areas of citrus cultivation has been shown to be effective in managing HLB and reducing management costs. As insecticide resistance is a major problem in sustainable management of ACP, rotation/alternation of insecticides with different chemistries and modes of action needs to be followed. Besides control of the insect vector, use of antibiotics has temporarily suppressed the symptoms of HLB in diseased trees. Recent efforts to discover and screen existing as well as new compounds for their antibiotic and antimicrobial activities have identified some promising molecules for HLB control. There is an urgent need to find a sustainable solution to the HLB menace through chemical control of ACP populations and within HLB-infected trees through the judicious use of labeled insecticides (existing and novel chemistries) and antibiotics in area-wide management programs with due consideration to the insecticide resistance problem. PMID:25491482

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

    PubMed

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

    2016-01-01

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

  12. 7 CFR 319.19 - Notice of quarantine.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Citrus Canker and Other Citrus Diseases... citrus canker disease (Xanthomonas citri (Hasse) Dowson) and other citrus diseases, the importation...

  13. 7 CFR 319.19 - Notice of quarantine.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Citrus Canker and Other Citrus Diseases... citrus canker disease (Xanthomonas citri (Hasse) Dowson) and other citrus diseases, the importation...

  14. 7 CFR 319.19 - Notice of quarantine.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Citrus Canker and Other Citrus Diseases... citrus canker disease (Xanthomonas citri (Hasse) Dowson) and other citrus diseases, the importation...

  15. 7 CFR 319.19 - Notice of quarantine.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Citrus Canker and Other Citrus Diseases... citrus canker disease (Xanthomonas citri (Hasse) Dowson) and other citrus diseases, the importation...

  16. 7 CFR 319.19 - Notice of quarantine.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Citrus Canker and Other Citrus Diseases... citrus canker disease (Xanthomonas citri (Hasse) Dowson) and other citrus diseases, the importation...

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-08-01

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

  19. 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...

  20. The effect of wind on dispersal of splash-borne Xanthomonas citri subsp citri at different heights and distances downwind of canker-infected grapefruit trees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas citri subsp citri (Xcc), which causes citrus canker, is a major pathogen of grapefruit and other canker-susceptible citrus species and cultivars grown in Florida and elsewhere. It is dispersed by rain splash, and wind promotes the dispersal of the pathogen. The aim of this study was to e...

  1. RNAi-based strategy for Asian citrus psyllid (Diaphorina citri) Control: A method to reduce the spread of citrus greening disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus greening disease is a serious bacterial disease of citrus worldwide and is vectored by the Asian citrus pysllid (Diaphorina Citri). The only effective control strategy includes vigorous control of the psyllid, primarily through heavy reliance on pesticides. As a more sustainable and environm...

  2. Identification and molecular characterization of nuclear Citrus leprosis virus, an unassigned Dichorhavirus genus member associated with citrus leprosis disease in Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  3. 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...

  4. Bacterial brown leaf spot of citrus, a new disease caused by Burkholderia andropogonis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new bacterial disease of citrus was recently identified in Florida and named as bacterial brown leaf spot (BBLS) of citrus. BBLS-infected citrus displayed flat, circular and brownish lesions with water-soaked margins surrounded by a chlorotic halo on leaves. Based on Biolog carbon source metabolic...

  5. Biofilm formation, epiphytic fitness, and canker development in Xanthomonas axonopodis pv. citri.

    PubMed

    Rigano, Luciano A; Siciliano, Florencia; Enrique, Ramón; Sendín, Lorena; Filippone, Paula; Torres, Pablo S; Qüesta, Julia; Dow, J Maxwell; Castagnaro, Atilio P; Vojnov, Adrián A; Marano, María Rosa

    2007-10-01

    The phytopathogenic bacterium Xanthomonas axonopodis pv. citri is responsible for the canker disease affecting citrus plants throughout the world. Here, we have evaluated the role of bacterial attachment and biofilm formation in leaf colonization during canker development on lemon leaves. Crystal violet staining and confocal laser scanning microscopy analysis of X. axonopodis pv. citri strains expressing the green fluorescent protein were used to evaluate attachment and biofilm formation on abiotic and biotic (leaf) surfaces. Wild-type X. axonopodis pv. citri attached to and formed a complex, structured biofilm on glass in minimal medium containing glucose. Similar attachment and structured biofilm formation also were seen on lemon leaves. An X. axonopodis pv. citri gumB mutant strain, defective in production of the extracellular polysaccharide xanthan, did not form a structured biofilm on either abiotic or biotic surfaces. In addition, the X. axonopodis pv. citri gumB showed reduced growth and survival on leaf surfaces and reduced disease symptoms. These findings suggest an important role for formation of biofilms in the epiphytic survival of X. axonopodis pv. citri prior to development of canker disease. PMID:17918624

  6. 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

  7. Packingline sanitizers for use against canker and decay pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interest in general sanitation in citrus packinghouses has turned to specific reduction of the canker organism from post harvest fruit and packinglines. Existing methods are not efficient and reduction of the bacterial colonies is not sufficient to allow transport and sale of fruit outside the quara...

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

    PubMed Central

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

    2011-01-01

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

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

    PubMed

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

    2011-11-01

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

  10. 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...

  11. 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

  12. Use of Psyllids in Early Identification of Huanglongbing Disease of Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), also known as citrus greening disease, is the most destructive disease of citrus. The disease is caused by three different species of phloem limited bacteria belonging to Candidatus Liberibacter. HLB was reported from Brazil in 2004 and Florida in 2005. Because of the non-specif...

  13. Role bending: complex relationships between viruses, hosts and vectors related to citrus leprosis, an emerging disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus leprosis is a difficult viral disease causing significant damage to citrus fruit in South America and Central America. The disease is marked by dramatic lesions on fruit, leaves and stems, resulting in an unmarketable product. The disease is caused by a set of unrelated cytoplasmic cileviruse...

  14. All Five Host-Range Variants of Xanthomonas citri Carry One pthA Homolog With 17.5 Repeats That Determines Pathogenicity on Citrus, but None Determine Host-Range Variation

    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...

  15. Adhesive tablet effective for treating canker sores in humans.

    PubMed

    Mizrahi, Boaz; Golenser, Jacob; Wolnerman, Joseph S; Domb, Abraham J

    2004-12-01

    A new mucoadhesive tablet, which releases natural active agents for pain reduction and rapid healing of canker sores, has been prepared and characterized. Adhesive tablets were prepared by compression molding of mixed powders of crosslinked polyacrylic acid and hydroxypropyl cellulose, absorbed with citrus oil and magnesium salt. The rate of tablet erosion and the rates of citrus oil and magnesium release were determined as well as the adhesiveness of the tablet using bovine gingival tissue and an Instron tensiometer. A clinical trial was conducted on 248 volunteers who had canker sores. Tablets adhere well to the mucosal tissue and gradually erode for 8 h releasing the citrus oil in a zero-order pattern whereas the magnesium is released during a period of 2 h. Both experimental and plain tablets were effective in reducing pain and decreasing healing time (p < 0.05) without adverse side effects. However, the tablets loaded with active agents were more effective. PMID:15459950

  16. 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 ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  18. Disease stress detection on citrus using a leaf optical model and field spectroscopy

    NASA Astrophysics Data System (ADS)

    Badnakhe, Mrunalini R.; Durbha, Surya; Adinarayana, J.

    2015-10-01

    As citrus is progressively contributing to horticultural production, wealth and economy of a country, it is necessary to understand the factors impacting citrus production. Gummosis is one of the most serious diseases causing considerable loss of overall citrus production and yield quality. A qualitative and quantitative analysis of citrus leaf biochemical properties are necessary to monitor the crop health, disease /pest stress and production. Total leaf chlorophyll content (Cab) represents one of the key biochemical factors which contributes in water, carbon, and energy exchange processes. Photosynthesis process in citrus will be disturbed as gummosis disease life cycle progresses. It is important to study Cab to evaluate the photosynthesis rate and disease stress. In this study the potential of Radiative Transfer (RT) PROSPECT model to retrieve Cab in citrus orchards was undertaken at different sites. The main goal is to evaluate the relationship between Cab and gummosis disease stress for citrus at various phenological stages. Inversion of PROSPECT model on measured hyperspectral data is carried out to extract the leaf level parameters influencing the disease. This model was inverted with the ground truth hyperspectral reading. The testing was separately initiated for healthy and infected plant leaves. This can lead to understand the disease stress on citrus leaves. For accuracy, raw spectra are filtered and processed which is an input parameter for Inversion PROSPECT model. Here, retrieved Cab content was correlated with gummosis disease stress in terms of oozing with R2 = 0.6021 and RMSE= 0.481272.

  19. 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

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

    PubMed Central

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

    2016-01-01

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

  1. 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...

  2. Resistance of sweet orange Pera (Citrus sinensis) genotypes to Xanthomonas citri subsp. citri under field conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker control is based on protection measures and eradication of plants infected with Xanthomonas citri subsp. citri. Although these measures show satisfactory results, the use of resistant genotypes is an important alternative for citrus canker control. The aim of this study was to evaluate...

  3. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  6. 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. Band selection using forward feature selection algorithm for citrus Huanglongbing disease detection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study attempted to classify spectrally similar data – obtained from aerial images of healthy citrus plants and the citrus greening disease (Huanglongbing) infected plants - using small differences without un-mixing the endmember components and therefore without the need for endmember library. H...

  8. Preharvest measures for postharvest improvement in marketable fresh citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker, caused by the bacterium Xanthomonas citri supsp. citri, (Xcc),was once the scourge of the Florida citrus industry from the early 1900’s on and off until the early 1990’s. It has been replaced, for the most part, by citrus greening but still continues to be a problem for Florida fres...

  9. Preharvest measures for postharvest improvement in marketable fresh citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus canker caused by the bacterium Xanthomonas citri supsp. citri, (Xcc), was once the scourge of the Florida citrus industry from the early 1900’s on and off until the early 1990’s. It has been replaced, for the most part, by citrus greening but still continues to be a problem for Florida fresh ...

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

    PubMed

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

    2016-07-01

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

  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. Canker Sores (For Parents)

    MedlinePlus

    ... if the sores appear more than two or three times a year. Diagnosis Tests are usually not done to diagnose canker sores, as a doctor can identify them based on medical history and physical exam alone. If your child has very frequent or severe bouts of recurrent ...

  13. 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

  14. Citrus leprosis research update

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  15. [Visible-NIR spectral feature of citrus greening disease].

    PubMed

    Li, Xiu-hua; Li, Min-zan; Won Suk, Lee; Reza, Ehsani; Ashish, Ratn Mishra

    2014-06-01

    Citrus greening (Huanglongbing, or HLB) is a devastating disease caused by Candidatus liberibacter which uses psyllids as vectors. It has no cure till now, and poses a huge threat to citrus industry around the world. In order to diagnose, assess and further control this disease, it is of great importance to first find a quick and effective way to detect it. Spectroscopy method, which was widely considered as a fast and nondestructive way, was adopted here to conduct a preliminary exploration of disease characteristics. In order to explore the spectral differences between the healthy and HLB infected leaves and canopies, this study measured the visible-NIR spectral reflectance of their leaves and canopies under lab and field conditions, respectively. The original spectral data were firstly preprocessed with smoothing (or moving average) and cluster average procedures, and then the first derivatives were also calculated to determine the red edge position (REP). In order to solve the multi-peak phenomenon problem, two interpolation methods (three-point Lagrangian interpolation and four-point linear extrapolation) were adopted to calculate the REP for each sample. The results showed that there were, obvious differences at the visible & NIR spectral reflectance between the healthy and HLB infected classes. Comparing with the healthy reflectance, the HLB reflectance was higher at the visible bands because of the yellowish symptoms on the infected leaves, and lower at NIR bands because the disease blocked water transportation to leaves. But the feature at NIR bands was easily affected by environmental factors such as light, background, etc. The REP was also a potential indicator to distinguish those two classes. The average REP was slowly moving toward red bands while the infection level was getting higher. The gap of the average REPs between the healthy and HLB classes reached to a maximum of 20 nm. Even in the dataset with relatively lower variation, the classification

  16. 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...

  17. Role Bending: Complex Relationships Between Viruses, Hosts, and Vectors Related to Citrus Leprosis, an Emerging Disease.

    PubMed

    Roy, Avijit; Hartung, John S; Schneider, William L; Shao, Jonathan; Leon, Guillermo; Melzer, Michael J; Beard, Jennifer J; Otero-Colina, Gabriel; Bauchan, Gary R; Ochoa, Ronald; Brlansky, Ronald H

    2015-07-01

    Citrus leprosis complex is an emerging disease in the Americas, associated with two unrelated taxa of viruses distributed in South, Central, and North America. The cytoplasmic viruses are Citrus leprosis virus C (CiLV-C), Citrus leprosis virus C2 (CiLV-C2), and Hibiscus green spot virus 2, and the nuclear viruses are Citrus leprosis virus N (CiLV-N) and Citrus necrotic spot virus. These viruses cause local lesion infections in all known hosts, with no natural systemic host identified to date. All leprosis viruses were believed to be transmitted by one species of mite, Brevipalpus phoenicis. However, mites collected from CiLV-C and CiLV-N infected citrus groves in Mexico were identified as B. yothersi and B. californicus sensu lato, respectively, and only B. yothersi was detected from CiLV-C2 and CiLV-N mixed infections in the Orinoco regions of Colombia. Phylogenetic analysis of the helicase, RNA-dependent RNA polymerase 2 domains and p24 gene amino acid sequences of cytoplasmic leprosis viruses showed a close relationship with recently deposited mosquito-borne negevirus sequences. Here, we present evidence that both cytoplasmic and nuclear viruses seem to replicate in viruliferous Brevipalpus species. The possible replication in the mite vector and the close relationship with mosquito borne negeviruses are consistent with the concept that members of the genus Cilevirus and Higrevirus originated in mites and citrus may play the role of mite virus vector. PMID:25775106

  18. 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...

  19. Identification of citrus greening disease using FTIR spectroscopy and chemometric analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), also called citrus greening disease, is difficult to detect in plants before visual symptoms appear, by which time the disease is likely to have spread to other nearby plants. An accurate, early detection method is needed to identify diseased plants. Current methods are both c...

  20. 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

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

    PubMed

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

    2015-08-01

    Nutrient assessment and management are important to maintain productivity in citrus orchards. In this study, laser-induced breakdown spectroscopy (LIBS) was applied for rapid and real-time detection of citrus anomalies. Laser-induced breakdown spectroscopy spectra were collected from citrus leaves with anomalies such as diseases (Huanglongbing, citrus canker) and nutrient deficiencies (iron, manganese, magnesium, zinc), and compared with those of healthy leaves. Baseline correction, wavelet multivariate denoising, and normalization techniques were applied to the LIBS spectra before analysis. After spectral pre-processing, features were extracted using principal component analysis and classified using two models, quadratic discriminant analysis and support vector machine (SVM). The SVM resulted in a high average classification accuracy of 97.5%, with high average canker classification accuracy (96.5%). LIBS peak analysis indicated that high intensities at 229.7, 247.9, 280.3, 393.5, 397.0, and 769.8 nm were observed of 11 peaks found in all the samples. Future studies using controlled experiments with variable nutrient applications are required for quantification of foliar nutrients by using LIBS-based sensing. PMID:26163130

  2. 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...

  3. 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...

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

    PubMed

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

    2013-07-01

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

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

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Commercial citrus-producing areas. 301.75-5 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The following are designated...

  6. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Commercial citrus-producing areas. 301.75-5 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The following are designated...

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

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Commercial citrus-producing areas. 301.75-5 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The following are designated...

  8. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Commercial citrus-producing areas. 301.75-5 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The following are designated...

  9. 7 CFR 301.75-5 - Commercial citrus-producing areas.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Commercial citrus-producing areas. 301.75-5 Section... INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-5 Commercial citrus-producing areas. (a) The following are designated...

  10. 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, ...

  11. Characterization of species of Diaporthe from wood cankers of grape in eastern North American vineyards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In eastern North American vineyards, Phomopsis cane and leaf spot (causal fungus Phomopsis viticola) is a destructive foliar disease, but is also associated with wood cankers, along with other fungi. To determine the association between foliar and wood-canker symptoms, we recovered Phomopsis isolate...

  12. 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 ...

  13. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  15. Transmission efficiency of Candidatus Liberibacter asiaticus and progression of Huanglongbing disease in graft- and psyllid-inoculated citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Candidatus Liberibacter asiaticus (Las) is a phloem-limited bacterium associated with Huanglongbing (HLB), one of the most destructive diseases of citrus in Florida and other citrus-producing countries. Natural transmission of Las occurs by the psyllid vector Diaphorina citri, but transmission can a...

  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. 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...

  18. Spectral angle mapper (SAM) based citrus greening disease detection using airborne hyperspectral imaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the past two decades, hyperspectral (HS) imaging has provided remarkable performance in ground object classification and disease identification, due to its high spectral resolution. In this paper, a novel method named “extended spectral angle mapping (ESAM)” is proposed to detect citrus greenin...

  19. 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...

  20. 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....

  1. 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 ...

  2. 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

  3. 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...

  4. 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

  5. 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

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

    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

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

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Funds for the replacement of commercial citrus trees...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-15 Funds for the replacement of commercial...

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

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Funds for the replacement of certified citrus nursery...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-17 Funds for the replacement of certified...

  9. 7 CFR 301.75-15 - Funds for the replacement of commercial citrus trees.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Funds for the replacement of certified citrus nursery...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-17 Funds for the replacement of certified...

  11. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Funds for the replacement of certified citrus nursery...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-17 Funds for the replacement of certified...

  12. 7 CFR 301.75-15 - Funds for the replacement of commercial citrus trees.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Funds for the replacement of commercial citrus trees...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-15 Funds for the replacement of commercial...

  13. 7 CFR 301.75-15 - Funds for the replacement of commercial citrus trees.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Funds for the replacement of commercial citrus trees...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-15 Funds for the replacement of commercial...

  14. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  15. 7 CFR 301.75-17 - Funds for the replacement of certified citrus nursery stock.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Funds for the replacement of certified citrus nursery...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-17 Funds for the replacement of certified...

  16. 7 CFR 301.75-15 - Funds for the replacement of commercial citrus trees.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Funds for the replacement of commercial citrus trees...) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE DOMESTIC QUARANTINE NOTICES Citrus Canker Notice of Quarantine and Regulations § 301.75-15 Funds for the replacement of commercial...

  17. “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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  19. 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 ...

  20. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hyperspectral imaging can provide unique spectral signatures for diseased vegetation. Airborne hyperspectral imaging can be used to detect potentially infected trees over a large area for rapid detection of infected zones. Ground inspection and management can be focused on these infected zones rath...

  2. Small RNA profiling reveals phosphorus deficiency as a contributing factor in symptom expression for Citrus Huanglongbing Disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 Ribonucleic acid (sRNA) play a vital role in regulating host responses to pa...

  3. 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...

  4. 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

    ... 22, 2007 and effective on March 16, 2007 (72 FR 13423-13428, Docket No. APHIS-2007-0032) that... effective on June 17, 2010 (75 FR 34322-34336, Docket No. APHIS- 2008-0015).\\4\\ Several commenters on the... / Wednesday, April 27, 2011 / Rules and Regulations#0;#0; ] DEPARTMENT OF AGRICULTURE Animal and Plant...

  5. Can insecticides protect citrus from HLB infection?

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  6. Certification Programs for Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  7. 76 FR 52543 - European Larch Canker; Expansion of Regulated Areas

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-23

    ... Animal and Plant Health Inspection Service 7 CFR Part 301 European Larch Canker; Expansion of Regulated... European larch canker to include additional areas in Maine. We are also correcting some misidentifications... of European larch canker from infested areas to noninfested areas. DATES: This interim rule...

  8. New Phomopsis species identified from wood cankers in eastern North American vineyards.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phomopsis cane and leaf spot, caused by the Ascomycete fungus Phomopsis viticola, is a destructive fruit and foliar disease in eastern North American vineyards. The pathogen typically attacks green tissues, but can also cause wood cankers, presumably due to infection of pruning wounds, as is the cas...

  9. 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 ...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  12. Antioxidant activity of Citrus fruits.

    PubMed

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

    2016-04-01

    Citrus is well-known for its nutrition and health-promotion values. This reputation is derived from the studies on the biological functions of phytochemicals in Citrus fruits and their derived products in the past decades. In recent years, the antioxidant activity of Citrus fruits and their roles in the prevention and treatment of various human chronic and degenerative diseases have attracted more and more attention. Citrus fruits are suggested to be a good source of dietary antioxidants. To have a better understanding of the mechanism underlying the antioxidant activity of Citrus fruits, we reviewed a study on the antioxidant activity of the phytochemicals in Citrus fruits, introduced methods for antioxidant activity evaluation, discussed the factors which influence the antioxidant activity of Citrus fruits, and summarized the underlying mechanism of action. Some suggestions for future study were also presented. PMID:26593569

  13. Bioactivity of citrus seed for mosquito-borne diseases larval control.

    PubMed

    Sumroiphon, Suchada; Yuwaree, Chumporn; Arunlertaree, Chumlong; Komalamisra, Narumon; Rongsriyam, Yupha

    2006-01-01

    This study aimed to determine the activity of citrus-seed extract against Ae. aegypti and Cx. quinquefasciatus larvae. The results indicated that ethanol citrus-seed extract showed the best killing effect on Ae. aegypti larvae, followed by local liquor, and water, with LC50 of 2,267.71, 6,389.22, and 135,319.40 ppm, respectively, whereas against Cx. quinquefasciatus larvae, the LC50 were 2,639.27, 5,611.66, and 127,411.88 ppm, respectively. Temephos was tested against Ae. aegypti larvae; the LC50 was 0.00057 ppm, which was nearly 4,000,000 times less than ethanol citrus-seed extract. When ethanol citrus-seed extract and temephos were tested with Nile tilapia (Oreochromis niloticus), a standard environmental organism, using LC50 of Ae. aegypti larvae at 2,267 and 0.00057 ppm, respectively, fish mortality was 0%. The results suggested that ethanol citrus-seed extract had no harmful effect on the fish, and that temephos, which is recommended by WHO, was safe for use in drinking water. However, when the LC50 dose that killed Ae. aegypti larvae for local liquor (6,389 ppm) and water extract (135,319 ppm) were tested with fish, the mortality rates were 35% and 100%, respectively. On the whole, the results suggested that ethanol citrus-seed extract is environmentally friendly and can be used in the control of Ae. aegypti and Cx. quinquefasciatus larvae. PMID:17547066

  14. 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...

  15. Draft genome sequence of diaporthe aspalathi isolate ms-ssc91 a fungus causing stem canker in soybean

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaporthe aspalathi (formerly D. phaseolorum var. meridionalis) is the causal agent of the southern stem canker disease in soybean. This disease can kill plants from the middle to the end of the growing season resulting in severe yield loss. The mechanisms of disease development and pathogen invasi...

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

    PubMed

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

    2015-07-01

    Phomopsis stem canker causes yield reductions on sunflower (Helianthus annuus L.) on several continents, including Australia, Europe, and North America. In the United States, Phomopsis stem canker incidence has increased 16-fold in the Northern Great Plains between 2001 and 2012. Although Diaporthe helianthi was assumed to be the sole causal agent in the United States, a newly described species, D. gulyae, was found to be the primary cause of Phomopsis stem canker in Australia. To determine the identity of Diaporthe spp. causing Phomopsis stem canker in the Northern Great Plains, 275 infected stems were collected between 2010 and 2012. Phylogenetic analyses of sequences of the ribosomal DNA internal transcribed spacer region, elongation factor subunit 1-α, and actin gene regions of representative isolates, in comparison with those of type specimens, confirmed two species (D. helianthi and D. gulyae) in the United States. Differences in aggressiveness between the two species were determined using the stem-wound method in the greenhouse; overall, D. helianthi and D. gulyae did not vary significantly (P≤0.05) in their aggressiveness at 10 and 14 days after inoculation. These findings indicate that both Diaporthe spp. have emerged as sunflower pathogens in the United States, and have implications on the management of this disease. PMID:26121367

  17. Citrus limonin glucoside supplementation decreased biomarkers of liver disease in overweight human subjects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Orange juice and mixtures of citrus limonoid glucosides isolated from orange juice or its byproducts demonstrated health benefits in human and animal studies. However, the risks and benefits of purified limonin glucoside (LG) in humans are unknown. Aim of this study was to determine the safety and m...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  19. 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

  20. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  2. 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...

  3. 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 ...

  4. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  6. 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

  7. Physical Changes in Satsuma Mandarin Leaf after Infection of Elsinoë fawcettii Causing Citrus Scab Disease

    PubMed Central

    Paudyal, Dilli Prasad; Hyun, Jae-Wook

    2015-01-01

    Citrus scab disease is one of the destructive diseases that reduce the value of fruit for the fresh market. We analyzed the process of symptom development after infection with scab pathogen Elsinoë fawcettii in the susceptible satsuma mandarin leaves to observe the structural modification against pathogen. The cuticle and epidermal cells along with 3–5 layers of mesophyll tissue were degraded 1–2 days post inoculation. Surrounding peripheral cells of degraded tissues grew rapidly and then enveloped the necrotic area along with the growing conidia. Cross sections through the lesion revealed hyphal colonization in epidermis and mesophyll tissues. In response to the pathogen colonization, host cell walls were lignified, inner cells were rapidly compartmentalized and a semi-circular boundary was formed that separated the infected region from the non-infected region, and finally prevented the intercellular pathogen spread. PMID:26674386

  8. Electronic tongue response to chemicals in orange juice that change concentration in relation to harvest maturity and citrus greening or Huanglongbing (HLB) disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an earlier study, the electronic tongue system (etongue) was used to differentiate between orange juice made from healthy fruit and from fruit affected by the citrus greening or Huanglongbing (HLB) disease. This study investigated the reaction of an etongue system to the main chemicals in orange ...

  9. Transmission rates of ‘Ca. Liberibacter asiaticus’ by Asian citrus psyllid are enhanced by the presence and developmental stage of citrus flush

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asian citrus psyllid (ACP) transmits a bacterium ‘Candidatus Liberibacter asiaticus’ (CLas) putatively responsible for a devastating citrus disease known as Asiatic huanglongbing (HLB) (= citrus greening disease). The psyllid and disease have invaded many citrus-growing regions around the world incl...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  11. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  13. Fourier transform infra-red spectroscopy using an attenuated total reflection probe to distinguish between Japanese larch, pine and citrus plants in healthy and diseased states.

    PubMed

    Gandolfo, D S; Mortimer, H; Woodhall, J W; Boonham, N

    2016-06-15

    FTIR spectroscopy coupled with an Attenuated Total Reflection (ATR) sampling probe has been demonstrated as a technique for detecting disease in plants. Spectral differences were detected in Japanese Larch (Larix kaempferi) infected with Phytophthora ramorum at 3403cm(-1) and 1730cm(-1), from pine (Pinus spp.) infected with Bursaphelenchus xylophilus at 1070cm(-1), 1425cm(-)1, 1621cm(-1) and 3403cm(-1) and from citrus (Citrus spp.) infected with 'Candidatus liberibacter' at 960cm(-1), 1087cm(-1), 1109cm(-1), 1154cm(-1), 1225cm(-1), 1385cm(-1), 1462cm(-1), 1707cm(-1), 2882cm(-1), 2982cm(-1) and 3650cm(-1). A spectral marker in healthy citrus has been identified as Pentanone but is absent from the diseased sample spectra. This agrees with recent work by Aksenov, 2014. Additionally, the spectral signature of Cutin was identified in the spectra of Pinus spp. and Citrus spp. and is consistent with work by Dubis, 1999 and Heredia-Guerrero, 2014. PMID:27054703

  14. Fourier transform infra-red spectroscopy using an attenuated total reflection probe to distinguish between Japanese larch, pine and citrus plants in healthy and diseased states

    NASA Astrophysics Data System (ADS)

    Gandolfo, D. S.; Mortimer, H.; Woodhall, J. W.; Boonham, N.

    2016-06-01

    FTIR spectroscopy coupled with an Attenuated Total Reflection (ATR) sampling probe has been demonstrated as a technique for detecting disease in plants. Spectral differences were detected in Japanese Larch (Larix kaempferi) infected with Phytophthora ramorum at 3403 cm-1 and 1730 cm-1, from pine (Pinus spp.) infected with Bursaphelenchus xylophilus at 1070 cm-1, 1425 cm-1, 1621 cm-1 and 3403 cm-1 and from citrus (Citrus spp.) infected with 'Candidatus liberibacter' at 960 cm-1, 1087 cm-1, 1109 cm-1, 1154 cm-1, 1225 cm-1, 1385 cm-1, 1462 cm-1, 1707 cm-1, 2882 cm-1, 2982 cm-1 and 3650 cm-1. A spectral marker in healthy citrus has been identified as Pentanone but is absent from the diseased sample spectra. This agrees with recent work by Aksenov, 2014. Additionally, the spectral signature of Cutin was identified in the spectra of Pinus spp. and Citrus spp. and is consistent with work by Dubis, 1999 and Heredia-Guerrero, 2014.

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

    PubMed

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

    2015-01-01

    After the sequencing of citrus genomes, gene function annotation is becoming a new challenge. Gene coexpression analysis can be employed for function annotation using publicly available microarray data sets. In this study, 230 sweet orange (Citrus sinensis) microarrays were used to construct seven coexpression networks, including one condition-independent and six condition-dependent (Citrus canker, Huanglongbing, leaves, flavedo, albedo, and flesh) networks. In total, these networks contain 37 633 edges among 6256 nodes (genes), which accounts for 52.11% measurable genes of the citrus microarray. Then, these networks were partitioned into functional modules using the Markov Cluster Algorithm. Significantly enriched Gene Ontology biological process terms and KEGG pathway terms were detected for 343 and 60 modules, respectively. Finally, independent verification of these networks was performed using another expression data of 371 genes. This study provides new targets for further functional analyses in citrus. PMID:26504573

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

    PubMed Central

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

    2015-01-01

    After the sequencing of citrus genomes, gene function annotation is becoming a new challenge. Gene coexpression analysis can be employed for function annotation using publicly available microarray data sets. In this study, 230 sweet orange (Citrus sinensis) microarrays were used to construct seven coexpression networks, including one condition-independent and six condition-dependent (Citrus canker, Huanglongbing, leaves, flavedo, albedo, and flesh) networks. In total, these networks contain 37 633 edges among 6256 nodes (genes), which accounts for 52.11% measurable genes of the citrus microarray. Then, these networks were partitioned into functional modules using the Markov Cluster Algorithm. Significantly enriched Gene Ontology biological process terms and KEGG pathway terms were detected for 343 and 60 modules, respectively. Finally, independent verification of these networks was performed using another expression data of 371 genes. This study provides new targets for further functional analyses in citrus. PMID:26504573

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

    PubMed Central

    Yun, Yeo Hong; Ahn, Geum Ran

    2015-01-01

    Acanthopanax divaricatus, a member of the Araliaceae family, has been used as an invigorant in traditional Korean medicine. During disease monitoring, a stem with small, irregular, brown lesions was sampled at a farm in Cheonan in 2011. The symptoms seen were sunken cankers and reddish-brown needles on the infected twig. The isolated fungal colonies were whitish, having crenated edges and aerial mycelium on the surface, and with black gregarious fruiting bodies. The reverse plate was creamy white. Conidia were 17~22 × 3.5~4.2 µm, fusiform, 4-septate, and straight to slightly curved. The nucleotide sequence of the partial translation elongation factor 1 alpha gene of the fungal isolate, shares 99% sequence identity with that of known Pestalotiopsis ellipsospora. Based on the results of the morphological and molecular analyses, the fungal isolate was identified as P. ellipsospora. In Korea, this is the first report of canker on A. divaricatus. PMID:26539058

  18. Orchard and nursery dynamics of the effect of interplanting citrus with guava for Huanglongbing, vector, and disease management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is an important pest of citrus in the United States of America primarily because it vectors ‘Candidatus Liberibacter asiaticus’, the bacterium putatively responsible for Asiatic huanglongbing (HLB). Asiatic HLB is con...

  19. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  1. Long term field evaluation reveals HLB resistance in Citrus relatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) is a destructive disease with no known cure. To identify sources of HLB resistance in the subfamily Aurantioideae to which citrus belongs, we conducted a six-year field trial under natural disease challenge conditions in an HLB endemic region. The study included 65 Citrus ...

  2. 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...

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

    PubMed

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

    2003-01-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  5. Evaluating citrus germplasm for huanglongbing (HLB) resistance: USDA-ARS Inoculation Program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri, is an important pest because it vectors bacteria responsible for a serious disease of citrus known as huanglongbing (citrus greening disease). USDA-ARS researchers recently established a program for screening citrus germplasm for resistance to the di...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  7. 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

  8. 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.

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

    PubMed

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

    2016-08-01

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

  10. 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

  11. Citrus Inventory

    NASA Technical Reports Server (NTRS)

    1994-01-01

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

  12. Citrus Inventory

    NASA Technical Reports Server (NTRS)

    1986-01-01

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

  13. Modified Citrus Pectin Reduces Galectin-3 Expression and Disease Severity in Experimental Acute Kidney Injury

    PubMed Central

    Kolatsi-Joannou, Maria; Price, Karen L.; Winyard, Paul J.; Long, David A.

    2011-01-01

    Galectin-3 is a β-galactoside binding lectin with roles in diverse processes including proliferation, apoptosis, inflammation and fibrosis which are dependent on different domains of the molecule and subcellular distribution. Although galectin-3 is known to be upregulated in acute kidney injury, the relative importance of its different domains and functions are poorly understood in the underlying pathogenesis. Therefore we experimentally modulated galectin-3 in folic acid (FA)-induced acute kidney injury utilising modified citrus pectin (MCP), a derivative of pectin which can bind to the galectin-3 carbohydrate recognition domain thereby predominantly antagonising functions linked to this role. Mice were pre-treated with normal or 1% MCP-supplemented drinking water one week before FA injection. During the initial injury phase, all FA-treated mice lost weight whilst their kidneys enlarged secondary to the renal insult; these gross changes were significantly lessened in the MCP group but this was not associated with significant changes in galectin-3 expression. At a histological level, MCP clearly reduced renal cell proliferation but did not affect apoptosis. Later, during the recovery phase at two weeks, MCP-treated mice demonstrated reduced galectin-3 in association with decreased renal fibrosis, macrophages, pro-inflammatory cytokine expression and apoptosis. Other renal galectins, galectin-1 and -9, were unchanged. Our data indicates that MCP is protective in experimental nephropathy with modulation of early proliferation and later galectin-3 expression, apoptosis and fibrosis. This raises the possibility that MCP may be a novel strategy to reduce renal injury in the long term, perhaps via carbohydrate binding-related functions of galectin-3. PMID:21494626

  14. 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...

  15. Susceptibility of sixteen citrus genotypes to Candidatus Liberibacter asiaticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) disease is the most serious threat to citrus production worldwide and in the last decade has devastated the Florida citrus industry. HLB is associated with a phloem-limited a-proteobacter Candidatus Liberibacter asiaticus (CLas) and its insect vector the Asian citrus psyllid (Dia...

  16. Huanglongbing increases Diplodia Stem End Rot in Citrus sinensis

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  19. Antimicrobial nanoemulsion formulation with improved penetration of foliar spray through citrus leaf cuticles to control citrus Huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is one of the most serious citrus diseases that threaten citrus industry worldwide. Because Candidatus Liberibacter asiaticus (Las) resides in citrus phloem, it is difficult to deliver an effective chemical compound into the phloem for control of HLB. In this study, a transcuticu...

  20. Ethanol attracts scolytid beetles to Phytophthora ramorum cankers on coast live oak

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Technical abstract: Ethanol in sapwood was analyzed along vertical transects, through small spot cankers and larger basal cankers, of Phytophthora ramorum-infected stems of Quercus agrifolia at three sites in California. Trees with large basal cankers, known to attract scolytid beetles, had a 4.3 ti...

  1. Spectral difference analysis and airborne imaging classification for citrus greening infected trees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus greening, also called Huanglongbing (HLB), became a devastating disease spread through citrus groves in Florida, since it was first found in 2005. Multispectral (MS) and hyperspectral (HS) airborne images of citrus groves in Florida were acquired to detect citrus greening infected trees in 20...

  2. Antibiosis and antixenosis resistance of Poncirus and Citrus x Poncirus germplasm to Diaphorina citri (Hemiptera: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, which is a worldwide pest that spreads citrus greening disease, may best be controlled by finding varieties of citrus that are resistant to the psyllid. We tested trifoliate citrus and trifoliate hybrids for resistance to the psyllid. Trifoliates were nearly all resistant,...

  3. 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...

  4. 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...

  5. 'Candidatus Liberibacter americanus', associated with citrus huanglongbing (greening disease) in São Paulo State, Brazil.

    PubMed

    Teixeira, Diva do Carmo; Saillard, Colette; Eveillard, Sandrine; Danet, Jean Luc; da Costa, Paulo Inácio; Ayres, Antonio Juliano; Bové, Joseph

    2005-09-01

    , were found to have identical or almost identical sequences. In contrast, the intergenic regions of the SPS-HLB liberibacter, 'Ca. L. asiaticus' and 'Ca. L. africanus' had quite different sequences, with similarity between 66.0 and 79.5%. These results confirm that the SPS-HLB liberibacter is a novel species for which the name 'Candidatus Liberibacter americanus' is proposed. Like the African and the Asian liberibacters, the 'American' liberibacter is restricted to the sieve tubes of the citrus host. The liberibacter could also be detected by PCR amplification of the 16S rRNA gene in Diaphorina citri, the psyllid vector of 'Ca. L. asiaticus', suggesting that this psyllid is also a vector of 'Ca. L. americanus' in SPS. 'Ca. L. americanus' was detected in 216 of 218 symptomatic leaf samples from 47 farms in 35 municipalities, while 'Ca. L. asiaticus' was detected in only 4 of the 218 samples, indicating that 'Ca. L. americanus' is the major cause of HLB in SPS. PMID:16166678

  6. Interference by western flower thrips in rearing Asian citrus psyllid: damage to host plants and facultative predation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is an important pest of citrus primarily because it vectors a bacterium responsible for a serious citrus disease known as huanglongbing (HLB) (also known as citrus greening disease). Researchers seeking solutions to HLB often depend on labor...

  7. 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...

  8. Citrus blight research

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  9. 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...

  10. The Xanthomonas axonopodis pv. citri flagellum is required for mature biofilm and canker development.

    PubMed

    Malamud, Florencia; Torres, Pablo S; Roeschlin, Roxana; Rigano, Luciano A; Enrique, Ramón; Bonomi, Hernán R; Castagnaro, Atilio P; Marano, María Rosa; Vojnov, Adrián A

    2011-03-01

    Xanthomonas axonopodis pv. citri (Xac) is the causative agent of citrus canker. This bacterium develops a characteristic biofilm on both biotic and abiotic surfaces. To evaluate the participation of the single flagellum of Xac in biofilm formation, mutants in the fliC (flagellin) and the flgE (hook) genes were generated. Swimming motility, assessed on 0.25 % agar plates, was markedly reduced in fliC and flgE mutants. However, the fliC and flgE mutants exhibited a flagellar-independent surface translocation on 0.5 % agar plates. Mutation of either the rpfF or the rpfC gene, which both encode proteins involved in cell-cell signalling mediated by diffusible signal factor (DSF), led to a reduction in both flagellar-dependent and flagellar-independent surface translocation, indicating a regulatory role for DSF in both types of motility. Confocal laser scanning microscopy of biofilms produced in static culture demonstrated that the flagellum is also involved in the formation of mushroom-shaped structures and water channels, and in the dispersion of biofilms. The presence of the flagellum was required for mature biofilm development on lemon leaf surfaces. The absence of flagellin produced a slight reduction in Xac pathogenicity and this reduction was more severe when the complete flagellum structure was absent. PMID:21109564

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

    PubMed

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

    2014-12-01

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

  12. 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 ...

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

    PubMed

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

    2013-01-15

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

  14. 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

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

    PubMed Central

    Fopa Fomeju, Berline; Falentin, Cyril; Lassalle, Gilles; Manzanares-Dauleux, Maria J.; Delourme, Régine

    2015-01-01

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

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

    PubMed

    Fopa Fomeju, Berline; Falentin, Cyril; Lassalle, Gilles; Manzanares-Dauleux, Maria J; Delourme, Régine

    2015-01-01

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

  17. Genome sequence of Valsa canker pathogens uncovers a potential adaptation of colonization of woody bark.

    PubMed

    Yin, Zhiyuan; Liu, Huiquan; Li, Zhengpeng; Ke, Xiwang; Dou, Daolong; Gao, Xiaoning; Song, Na; Dai, Qingqing; Wu, Yuxing; Xu, Jin-Rong; Kang, Zhensheng; Huang, Lili

    2015-12-01

    Canker caused by ascomycetous Valsa species are among the most destructive diseases of woody plants worldwide. These pathogens are distinct from other pathogens because they only effectively attack tree bark in the field. To unravel the potential adaptation mechanism of bark colonization, we examined the genomes of Valsa mali and Valsa pyri that preferentially infect apple and pear, respectively. We reported the 44.7 and 35.7 Mb genomes of V. mali and V. pyri, respectively. We also identified the potential genomic determinants of wood colonization by comparing them with related cereal pathogens. Both genomes encode a plethora of pathogenicity-related genes involved in plant cell wall degradation and secondary metabolite biosynthesis. In order to adapt to the nutrient limitation and low pH environment in bark, they seem to employ membrane transporters associated with nitrogen uptake and secrete proteases predominantly with acidic pH optima. Remarkably, both Valsa genomes are especially suited for pectin decomposition, but are limited in lignocellulose and cutin degradation. Besides many similarities, the two genomes show distinct variations in many secondary metabolism gene clusters. Our results show a potential adaptation of Valsa canker pathogens to colonize woody bark. Secondary metabolism gene clusters are probably responsible for this host specificity. PMID:26137988

  18. 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 β-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

  19. Diversity of Diaporthe species associated with wood cankers of fruit and nut crops in northern California.

    PubMed

    Lawrence, Daniel P; Travadon, Renaud; Baumgartner, Kendra

    2015-01-01

    Diaporthe ampelina, causal agent of Phomopsis cane and leaf spot of grapevine (Vitis vinifera L.) is isolated frequently from grapevine wood cankers, causing Phomopsis dieback. The latter disease is associated with four other Diaporthe species, three of which also are reported from hosts other than grape. To better understand the role of this Diaporthe community in Phomopsis dieback of grapevine and the potential for infection routes among alternate hosts, 76 Diaporthe isolates were recovered from wood cankers of cultivated grape, pear, apricot, almond and the wild host willow in four California counties. Isolates were characterized morphologically and assigned to species based on multigene sequence analyses. This study identified eight Diaporthe species from grapevine and one novel taxon from willow, D. benedicti. We report the first findings of D. australafricana and D. novem in North America. Our findings also expand the host ranges of D. ambigua to apricot and willow, D. australafricana to almond and willow, D. chamaeropis to grapevine and willow, D. foeniculina to willow and D. novem to almond. The generalists D. ambigua and D. eres were the most genetically diverse species, based on high nucleotide and haplotypic diversity, followed by the grapevine specialist D. ampelina. Analyses based on multilocus linkage disequilibrium could not reject the hypothesis of random mating for D. ambigua, which is further supported by relatively high haplotypic diversity, reports of both mating types and reports of successful matings in vitro. Pathogenicity assays revealed that D. ampelina was the most pathogenic species to grapevine wood. PMID:26240309

  20. 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

  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. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  4. Mitigating citrus huanglongbing via effective application of antimicrobial compounds and thermotherapy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a serious citrus disease that threatens the citrus industry worldwide. HLB is a systemic, infectious disease and the putative causal bacterium Candidatus Liberibacter asiaticus (Las) resides in citrus phloem. In this study, the effects of heat treatment, chemical formulations,...

  5. An evaluation of different plant genotypes for rearing Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psylloidea)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP) is the vector of bacteria responsible for a serious citrus disease known as huanglongbing (also known as citrus greening disease). Many research endeavors on ACP are dependent on a steady supply of ACP, which can be facilitated using a laboratory or greenhouse colony m...

  6. Factors affecting transmission rates of 'Candidatus Liberibacter asiaticus' by Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP), Diaphorina citri, is an important pest because it transmits a bacterium ‘Candidatus Liberibacter asiaticus’ (CLas) responsible for a serious disease of citrus known as Asiatic huanglongbing (citrus greening disease). USDA-ARS researchers recently established a program...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  8. Quarantine, sanitary and ceritification programs to prevent citrus quarantine pests in the USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus germplasm has moved from its geographic origin in the Far East, distributing also several graft-transmissible diseases in all the citrus growing areas of the world. In spite of the plethora of such diseases, the citrus industry has survived through the decades and prospered in many countries ...

  9. 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 (...

  10. 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...

  11. 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...

  12. 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.

  13. 7 CFR 301.75-1 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... disease caused by strains of the bacterium Xanthomonas axonopodis pv. citri. Commercial citrus grove. An... contaminated with bacteria that cause citrus canker. Grove. Any tree or stand of trees maintained to produce... bacteria that cause citrus canker. Infestation. The presence of a plant or plants infected with...

  14. Genome-wide comparative analysis reveals possible common ancestors of nucleotide-binding sites domain containing genes in hybrid Citrus sinensis genome and original Citrus clementina genome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We identified and re-annotated candidate disease resistance (R) genes with nucleotide-binding sites (NBS) domain from a Citrus clementina genome and two complete Citrus sinensis genome sequences (one from the USA and one from China). We found similar numbers of NBS genes from three citrus genomes, r...

  15. 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

  16. 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

  17. 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...

  18. Breeding for resistance/tolerance to HLB within citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) disease is now widespread across the southern half of the Florida peninsula, and is found in every citrus producing county and has now been found in California and Texas as well. The disease greatly debilitates trees and sometimes contributes to tree death. Development of citrus ...

  19. Citrus breeding, genetics and genomics in Japan.

    PubMed

    Omura, Mitsuo; Shimada, Takehiko

    2016-01-01

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

  20. Citrus breeding, genetics and genomics in Japan

    PubMed Central

    Omura, Mitsuo; Shimada, Takehiko

    2016-01-01

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

  1. 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

  2. BARK CANKER OF UNKNOWN ETIOLOGY DEVELOPING ON PECAN CARYA ILLINOENSIS TREES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pecan trees in a five-year-old orchard of 17 cultivars had symptoms of an unusual bark canker first noticed in October, 2002. Symptoms appeared from ground line up to 3 meters on the central leader and most likely were initiated during the summer of 2002. Cankers developed around buds of the trunk...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  4. Summer heat and low soil organic matter influence severity of hazelnut Cytospora canker.

    PubMed

    Lamichhane, Jay Ram; Fabi, Alfredo; Varvaro, Leonardo

    2014-04-01

    Cytospora canker, caused by the fungus Cytospora corylicola, is present in hazelnut production areas worldwide. The disease is widespread throughout the main production areas of Italy. The causal agent is considered to be a secondary invader of damaged tissue that attacks mainly stressed plants. However, little is known of disease severity and stress factors that predispose plants to infection. In particular, the role of pedoclimatic factors was investigated. Direct survey indicated that disease severity varied across several study sites. Geostatistics showed a strong positive correlation between disease severity index and summer heat (r = 0.80 and 0.91 for July and August, respectively) and strong negative correlation between disease severity index and soil organic matter (r = -0.78). A moderate positive correlation between disease severity index and magnesium/potassium ratio (r = 0.58) and moderate negative correlations between disease severity index and total soil nitrogen (r = -0.53), thermal shock (r = -0.46), and rainfall (r = -0.53) were determined. No significant correlation between disease severity index and soil aluminum (r = -0.35), soil pH (r = -0.01), and plant age (r = -0.38) was found. PMID:24168042

  5. 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...

  6. Effect of PGRs and fungicides on huanglongbing-related preharvest fruit drop of citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The severe citrus disease Huanglongbing (HLB) in Florida has resulted in widespread tree decline, and overall citrus production is now the lowest it has been in 50 years. More than 80 percent of Florida citrus trees are huanglongbing-affected, and most growers attempt to sustain production on infect...

  7. 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...

  8. 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...

  9. HLB resistance and tolerance in citrus scion development at the US Horticultural Research Laboratory

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is severely impacting Florida citrus and threatening industries in the rest of the US. Productivity declines in many HLB-affected trees. Fruit size and quality often diminish as the disease advances. The USDA citrus scion breeding program is charged with producing improved citrus...

  10. 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...

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

    PubMed

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

    2016-03-01

    Clavibacter michiganensis subsp. michiganensis, the causal agent of bacterial canker and wilt of tomato, is considered to be one of the most important bacterial pathogens worldwide. In the year 2000 there was an increase in the number of infected greenhouses and in the severity of the disease in Israel. As part of the effort to cope with the disease, a comprehensive survey was conducted. Scouts recorded disease severity monthly in 681 production units. At the end of the season the scouts met with the growers and together recorded relevant details about the crop and cultural practices employed. The results suggested an absence of anisotropy pattern in the study region. Global Moran's I analysis showed that disease severity had significant spatial autocorrelation. The strongest spatial autocorrelation occurred within a 1,500 m neighborhood, which is comparable to the distance between production units maintained by one grower (Farm). Next, we tested three groups of variables including or excluding the Farm as a variable. When the Farm was included the explained variation increased in all the studied models. Overall, results of this study demonstrate that the most influential factor on bacterial canker severity was the Farm. This variable probably encompasses variation in experience, differences in agricultural practices between growers, and the quality of implementation of management practices. PMID:26623996

  12. Electronic Tongue Response to Chemicals in Orange Juice that Change Concentration in Relation to Harvest Maturity and Citrus Greening or Huanglongbing (HLB) Disease.

    PubMed

    Raithore, Smita; Bai, Jinhe; Plotto, Anne; Manthey, John; Irey, Mike; Baldwin, Elizabeth

    2015-01-01

    In an earlier study, an electronic tongue system (e-tongue) has been used to differentiate between orange juice made from healthy fruit and from fruit affected by the citrus greening or Huanglongbing (HLB) disease. This study investigated the reaction of an e-tongue system to the main chemicals in orange juice that impact flavor and health benefits and are also impacted by HLB. Orange juice was spiked with sucrose (0.2-5.0 g/100 mL), citric acid (0.1%-3.0% g/100 mL) and potassium chloride (0.1-3.0 g/100 mL) as well as the secondary metabolites nomilin (1-30 µg/mL), limonin (1-30 µg/mL), limonin glucoside (30-200 µg/mL), hesperidin (30-400 µg/mL) and hesperetin (30-400 µg/mL). Performance of Alpha MOS sensor sets #1 (pharmaceutical) and #5 (food) were compared for the same samples, with sensor set #1 generally giving better separation than sensor set #5 for sucrose, sensor set #5 giving better separation for nomilin and limonin, both sets being efficient at separating citric acid, potassium chloride, hesperitin and limonin glucoside, and neither set discriminating hesperidin efficiently. Orange juice made from fruit over the harvest season and from fruit harvested from healthy or HLB-affected trees were separated by harvest maturity, disease state and disease severity. PMID:26633411

  13. Effects of hirami lemon, Citrus depressa Hayata, leaf meal in diets on the immune response and disease resistance of juvenile barramundi, Lates calcarifer (bloch), against Aeromonas hydrophila.

    PubMed

    Shiu, Ya-Li; Lin, Hsueh-Li; Chi, Chia-Chun; Yeh, Shinn-Pyng; Liu, Chun-Hung

    2016-08-01

    The present study was conducted to evaluate the dietary supplementation of leaf meal from Citrus depressa Hayata on the growth, innate immune response, and disease resistance of juvenile barramundi, Lates calcarifer. Four diets were formulated to contain 0% (control), 1% (C1), 3% (C3), and 5% (C5) leaf meal, respectively. During a 56 d feeding trial, fish survival, growth performance, and feed efficiency were not significantly different among all groups. For immune response, respiratory burst, superoxide dismutase and lysozyme activities were not significantly different among all groups. However, fish fed the C5 diet for 56 d had significantly higher phagocytic activity. Also, fish fed C3 and C5 diets had significantly higher Mx gene expressions in spleens and head kidneys with nerve necrosis virus injections after 24 h. Disease resistance against Aeromonas hydrophila was increased by the C5 diet. In this study, barramundi fed on a diet containing 5% C. depressa Hayata leaf meal had significantly better innate immune response and disease resistance against A. hydrophila. PMID:27265807

  14. Electronic Tongue Response to Chemicals in Orange Juice that Change Concentration in Relation to Harvest Maturity and Citrus Greening or Huanglongbing (HLB) Disease

    PubMed Central

    Raithore, Smita; Bai, Jinhe; Plotto, Anne; Manthey, John; Irey, Mike; Baldwin, Elizabeth

    2015-01-01

    In an earlier study, an electronic tongue system (e-tongue) has been used to differentiate between orange juice made from healthy fruit and from fruit affected by the citrus greening or Huanglongbing (HLB) disease. This study investigated the reaction of an e-tongue system to the main chemicals in orange juice that impact flavor and health benefits and are also impacted by HLB. Orange juice was spiked with sucrose (0.2–5.0 g/100 mL), citric acid (0.1%–3.0% g/100 mL) and potassium chloride (0.1–3.0 g/100 mL) as well as the secondary metabolites nomilin (1–30 µg/mL), limonin (1–30 µg/mL), limonin glucoside (30–200 µg/mL), hesperidin (30–400 µg/mL) and hesperetin (30–400 µg/mL). Performance of Alpha MOS sensor sets #1 (pharmaceutical) and #5 (food) were compared for the same samples, with sensor set #1 generally giving better separation than sensor set #5 for sucrose, sensor set #5 giving better separation for nomilin and limonin, both sets being efficient at separating citric acid, potassium chloride, hesperitin and limonin glucoside, and neither set discriminating hesperidin efficiently. Orange juice made from fruit over the harvest season and from fruit harvested from healthy or HLB-affected trees were separated by harvest maturity, disease state and disease severity. PMID:26633411

  15. First steps towards rescuing Las-infected citrus germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) disease is having significant impact on the USDA citrus breeding program as it has shown up in a number of trees which exist only in a virtually irreplaceable collection of diverse citrus types. It is critical that we rescue HLB-free budwood from elite germplasm that is HLB-patho...

  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. An evaluation of candidate repellents against Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  18. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  20. Coccinellid predators do not track populations of the Asian citrus phyllid (Diaphorina citri) in citrus in Puerto Rico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yellow sticky cards were used to survey populations of Diaphorina citri, the vector of Huanglongbing, the most devastating bacterial disease of citrus worldwide. The numbers of coccinellids, potential predators of Diaphorina citri, were also surveyed. Citrus surveyed included a variety of species (V...

  1. Incidence of the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae) and its parasitoid Tamarixia radiata (Hymenoptera: Eulophidae) in Florida citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diaphorina citri Kuwayama, vectors the bacterium Candidatus Liberibacter asiaticus, one of the causal organisms of the devastating citrus disease “huanglongbing” or citrus greening. In the United States, D. citri was first discovered in Florida, in 1998. Tamarixia radiata Waterston, was imported fro...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  3. Citrus Waste Biomass Program

    SciTech Connect

    Karel Grohman; Scott Stevenson

    2007-01-30

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

  4. 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

  5. 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...

  6. Optimized Quantification of Unculturable Candidatus Liberibacter Species Causing Citrus Huanglongbing in Host Plants by Real-Time PCR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) caused by the phloem-limited and psyllid-vectored Candidatus Liberibacter spp. is a destructive disease of citrus that is rapidly increasing in importance. The disease was recently reported in the principle citrus producing areas of São Paulo, Brazil in 2004 and of Florida...

  7. Citrus Flavonoids as Regulators of Lipoprotein Metabolism and Atherosclerosis.

    PubMed

    Mulvihill, Erin E; Burke, Amy C; Huff, Murray W

    2016-07-17

    Citrus flavonoids are polyphenolic compounds with significant biological properties. This review summarizes recent advances in understanding the ability of citrus flavonoids to modulate lipid metabolism, other metabolic parameters related to the metabolic syndrome, and atherosclerosis. Citrus flavonoids, including naringenin, hesperitin, nobiletin, and tangeretin, have emerged as potential therapeutics for the treatment of metabolic dysregulation. Epidemiological studies reveal an association between the intake of citrus flavonoid-containing foods and a decreased incidence of cardiovascular disease. Studies in cell culture and animal models, as well as a limited number of clinical studies, reveal the lipid-lowering, insulin-sensitizing, antihypertensive, and anti-inflammatory properties of citrus flavonoids. In animal models, supplementation of rodent diets with citrus flavonoids prevents hepatic steatosis, dyslipidemia, and insulin resistance primarily through inhibition of hepatic fatty acid synthesis and increased fatty acid oxidation. Citrus flavonoids blunt the inflammatory response in metabolically important tissues including liver, adipose, kidney, and the aorta. The mechanisms underlying flavonoid-induced metabolic regulation have not been completely established, although several potential targets have been identified. In mouse models, citrus flavonoids show marked suppression of atherogenesis through improved metabolic parameters as well as through direct impact on the vessel wall. Recent studies support a role for citrus flavonoids in the treatment of dyslipidemia, insulin resistance, hepatic steatosis, obesity, and atherosclerosis. Larger human studies examining dose, bioavailability, efficacy, and safety are required to promote the development of these promising therapeutic agents. PMID:27146015

  8. Nobiletin, a citrus flavonoid, improves cognitive impairment and reduces soluble Aβ levels in a triple transgenic mouse model of Alzheimer's disease (3XTg-AD).

    PubMed

    Nakajima, Akira; Aoyama, Yuki; Shin, Eun-Joo; Nam, Yunsung; Kim, Hyoung-Chun; Nagai, Taku; Yokosuka, Akihito; Mimaki, Yoshihiro; Yokoi, Tsuyoshi; Ohizumi, Yasushi; Yamada, Kiyofumi

    2015-08-01

    Alzheimer's disease (AD), the most common form of dementia among the elderly, is characterized by the progressive decline of cognitive function. Increasing evidence indicates that the production and accumulation of amyloid β (Aβ), particularly soluble Aβ oligomers, is central to the pathogenesis of AD. Our recent studies have demonstrated that nobiletin, a polymethoxylated flavone from citrus peels, ameliorates learning and memory impairment in olfactory-bulbectomized mice, amyloid precursor protein transgenic mice, NMDA receptor antagonist-treated mice, and senescence-accelerated mouse prone 8. Here, we present evidence that this natural compound improves cognitive impairment and reduces soluble Aβ levels in a triple transgenic mouse model of AD (3XTg-AD) that progressively develops amyloid plaques, neurofibrillary tangles, and cognitive impairments. Treatment with nobiletin (30 mg/kg) for 3 months reversed the impairment of short-term memory and recognition memory in 3XTg-AD mice. Our ELISA analysis also showed that nobiletin reduced the levels of soluble Aβ1-40 in the brain of 3XTg-AD mice. Furthermore, nobiletin reduced ROS levels in the hippocampus of 3XTg-AD as well as wild-type mice. These results suggest that this natural compound has potential to become a novel drug for the treatment and prevention of AD. PMID:25913833

  9. Comparative proteomic analysis reveals that T3SS, Tfp, and xanthan gum are key factors in initial stages of Citrus sinensis infection by Xanthomonas citri subsp. citri.

    PubMed

    Facincani, Agda P; Moreira, Leandro M; Soares, Márcia R; Ferreira, Cristiano B; Ferreira, Rafael M; Ferro, Maria I T; Ferro, Jesus A; Gozzo, Fabio C; de Oliveira, Julio C F

    2014-03-01

    The bacteria Xanthomonas citri subsp. citri (Xac) is the causal agent of citrus canker. The disease symptoms are characterized by localized host cell hyperplasia followed by tissue necrosis at the infected area. An arsenal of bacterial pathogenicity- and virulence-related proteins is expressed to ensure a successful infection process. At the post-genomic stage of Xac, we used a proteomic approach to analyze the proteins that are displayed differentially over time when the pathogen attacks the host plant. Protein extracts were prepared from infectious Xac grown in inducing medium (XAM1) for 24 h or from host citrus plants for 3 or 5 days after infection, detached times to evaluate the adaptation and virulence of the pathogen. The protein extracts were proteolyzed, and the peptides derived from tryptic digestion were investigated using liquid chromatography and tandem mass spectrometry. Changes in the protein expression profile were compared with the Xac genome and the proteome recently described under non-infectious conditions. An analysis of the proteome of Xac under infectious conditions revealed proteins directly involved in virulence such as the type III secretion system (T3SS) and effector proteins (T3SS-e), the type IV pilus (Tfp), and xanthan gum biosynthesis. Moreover, four new mutants related to proteins detected in the proteome and with different functions exhibited reduced virulence relative to the wild-type proteins. The results of the proteome analysis of infectious Xac define the processes of adaptation to the host and demonstrate the induction of the virulence factors of Xac involved in plant-pathogen interactions. PMID:24676796

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

    PubMed

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

    2009-02-01

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

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

    PubMed

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

    2011-12-01

    The citrus cultivar Carrizo is the single most important rootstock to the US citrus industry and has resistance or tolerance to a number of major citrus diseases, including citrus tristeza virus, foot rot, and Huanglongbing (HLB, citrus greening). A Carrizo genomic sequence database providing approximately 3.5×genome coverage (haploid genome size approximately 367 Mb) was populated through 454 GS FLX shotgun sequencing. Analysis of the repetitive DNA fraction indicated a total interspersed repeat fraction of 36.5%. Assembly and characterization of abundant citrus Ty3/gypsy elements revealed a novel type of element containing open reading frames encoding a viral RNA-silencing suppressor protein (RNA binding protein, rbp) and a plant cytokinin riboside 5′-monophosphate phosphoribohydrolase-related protein (LONELY GUY, log). Similar gypsy elements were identified in the Populus trichocarpa genome. Gene-coding region analysis indicated that 24.4% of the nonrepetitive reads contained genic regions. The depth of genome coverage was sufficient to allow accurate assembly of constituent genes, including a putative phloem-expressed gene. The development of the Carrizo database (http://citrus.pw.usda.gov/) will contribute to characterization of agronomically significant loci and provide a publicly available genomic resource to the citrus research community. PMID:22133378

  12. Widespread Distribution of Fungivorus Aphelenchoides spp. in Blight Cankers on American Chestnut Trees.

    PubMed

    Griffin, G J; Eisenback, J D; Oldham, K

    2012-12-01

    Previously we showed in laboratory studies that the fungivorus nematode, Aphelenchoides hylurgi, was attracted to and fed upon the chestnut blight fungus, Cryphonectria parasitica, from American chestnut bark cankers and was a carrier of biocontrol, white hypovirulent C. parasitica strains. In the present field study, we recovered Aphelenchoides spp. in almost all (97.0 %) of 133 blight canker tissue assays (three 5-g samples each) from four eastern states. High mean population densities (227 to 474 nematodes per 5 g tissue) of Aphelenchoides spp. were recovered from cankers in Virginia, West Virginia, and Tennessee but not from New Hampshire (mean = 75 nematodes per 5 g tissue). Overall, most canker assays yielded population densities less than 200 nematodes per 5 g tissue. All of 12 very small or young cankers yielded a few to many Aphelenchoides spp. Regression analysis indicated greatest recovery of Aphelenchoides spp. occurred in the month of May (r = 0.94). The results indicate that Aphelenchoides spp. appear to be widespread in blight cankers on American chestnut trees and could play a role in biocontrol of chestnut blight. PMID:23482428

  13. Localized autoinoculation and dissemination of Isaria fumosorosea for control of the Asian citrus psyllid in South Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayama, vectors the causal organism of citrus greening disease. Integrated strategies are needed to control D. citri in south Texas. Control approaches involving entomopathogenic fungi may be useful on ornamental and abandoned citrus and other rutaceous...

  14. 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...

  15. 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...

  16. Candidatus Liberibacter asiaticus and Huanglongbing effects on citrus seeds and seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a devastating disease of citrus and threatens the citrus industry worldwide. The suspected causal agent of the disease is a phloem-limited bacterium of the genus Candidatus Liberibacter, transmitted through insect vector or grafting with diseased budwood. Currently, most seed...

  17. Resistance and tolerance to huanglongbing in citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is severely impacting Florida citrus. Productivity declines in many HLB-affected genotypes, often with greatly thinned canopies. Fruit size and quality are often adversely affected as the disease advances. HLB was assessed in diverse cultivars in commercial groves with high HLB-i...

  18. NPDN Citrus Greening Diagnostic and Detection Efforts

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  19. Huanglongbing resistance and tolerance in citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is severely impacting Florida citrus. Productivity declines in many HLB-affected genotypes, often with greatly thinned canopies. Fruit size and quality are often adversely affected as the disease advances. HLB was assessed in diverse cultivars in commercial groves with high HLB-i...

  20. 2006 University Citrus Pest Management Guide: Tristeza

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is a major cause of the decline and eventual death of trees on sour orange rootstocks. Initially, affected trees have small leaves and twig dieback. Diseased trees often produce a crop of very small fruit. Eventually, large limbs die back and the tree gradually declines...

  1. Probing behaviors of adult Asian citrus psyllid (Hemiptera: Psyllidae)are not appreciably affected by soil application of field-rate aldicarb to citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2005, Huanglongbing disease (HLB), also known as citrus greening, was discovered in Florida. The presumptive causal agent of this disease is the phloem-limited bacterium Candidatus Liberibacter asiaticus (Las), which is transmitted by the Asian citrus psyllid,Diaphorina citri Kuwayama. Following ...

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

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  3. 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-...

  4. Quantitative distribution of Candidatus Liberibacter asiaticus in the aerial parts of the field grown HLB-infected citrus trees in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid, Diaphorina citri Kuwayanna, one of the vectors for citrus greening disease or Huanglongbing (HLB) has been present in Texas for over a decade, but the detection of the disease is recent. HLB has been confirmed in only two adjacent commercial citrus groves of grapefruit and...

  5. 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...

  6. Genome analysis of the kiwifruit canker pathogen Pseudomonas syringae pv. actinidiae biovar 5.

    PubMed

    Fujikawa, Takashi; Sawada, Hiroyuki

    2016-01-01

    Pseudomonas syringae pv. actinidiae (Psa) is a destructive pathogen of kiwifruit bacterial canker disease, causing severe economic losses to kiwifruit industry worldwide. Biovar 5 is the most recently reported biovar of Psa, and is found in only a local area of Japan at present. There is not much information of genetic characteristics of biovar 5. Thus, the genome of biovar 5 was sequenced and analyzed to clarify its detailed genetic characteristics. Here, the genomes of strain MAFF 212056 and MAFF 212061 of biovar 5 were estimated to be about 6.3 Mbp and 6.5 Mbp, respectively, and their phylogenetic positions were proved to be near that of biovar 2 in the phylogenetic tree. However, it was confirmed that biovar 5 had neither the coronatine biosynthetic genes conserved in biovar 2, its phylogenetic neighbor, nor the phaseolotoxin biosynthetic genes conserved in biovar 1, Japanese native pathogen. In addition, 45 genes of type III secreted effectors were identified in biovar 5 genomes, showing that their composition is different from that in the other biovars. Moreover, some biovar 5-specific regions were identified. Then, biovar 5-specific PCR primers for targeting these regions were designed, and proved to be applicable for detecting biovar 5 specifically. PMID:26891997

  7. Genome analysis of the kiwifruit canker pathogen Pseudomonas syringae pv. actinidiae biovar 5

    PubMed Central

    Fujikawa, Takashi; Sawada, Hiroyuki

    2016-01-01

    Pseudomonas syringae pv. actinidiae (Psa) is a destructive pathogen of kiwifruit bacterial canker disease, causing severe economic losses to kiwifruit industry worldwide. Biovar 5 is the most recently reported biovar of Psa, and is found in only a local area of Japan at present. There is not much information of genetic characteristics of biovar 5. Thus, the genome of biovar 5 was sequenced and analyzed to clarify its detailed genetic characteristics. Here, the genomes of strain MAFF 212056 and MAFF 212061 of biovar 5 were estimated to be about 6.3 Mbp and 6.5 Mbp, respectively, and their phylogenetic positions were proved to be near that of biovar 2 in the phylogenetic tree. However, it was confirmed that biovar 5 had neither the coronatine biosynthetic genes conserved in biovar 2, its phylogenetic neighbor, nor the phaseolotoxin biosynthetic genes conserved in biovar 1, Japanese native pathogen. In addition, 45 genes of type III secreted effectors were identified in biovar 5 genomes, showing that their composition is different from that in the other biovars. Moreover, some biovar 5-specific regions were identified. Then, biovar 5-specific PCR primers for targeting these regions were designed, and proved to be applicable for detecting biovar 5 specifically. PMID:26891997

  8. Diseases of Pacific Coast conifers. Agriculture handbook

    SciTech Connect

    Scharpf, R.F.

    1993-06-01

    The handbook provides basic information needed to identify the common diseases of Pacific Coast conifers. Hosts, distribution, disease cycles, and identifying characteristics are described for more than 150 diseases, including cankers, diebacks, galls, rusts, needle diseases, root diseases, mistletoes, and rots. Diseases in which abiotic factors are involved are also described. For some groups of diseases, a descriptive key to field identification is included.

  9. Occurrence of fludioxonil resistance in penicillium digitatum from citrus in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Penicillium digitatum is the causal agent of green mold, the most important postharvest disease of citrus (Citrus spp.). Fludioxonil is marketed as either a solo product or in combination with azoxystrobin for control of green mold and other postharvest diseases. Baseline sensitivity to fludioxonil ...

  10. Feasibility study on Huanglongbing (citrus greening) detection based on WorldView-2 satellite imagery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a devastating citrus disease worldwide, without any known cure. Since this disease shows visible symptoms on newly developed canopies, some remote sensing methods have been used as a tool for detection. In order to explore a fast way to monitor HLB in large citrus groves, a sa...

  11. 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...

  12. 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...

  13. Application of time-lapse ERT to Characterize Soil-Water-Disease Interactions of Citrus Orchard - Case Study

    NASA Astrophysics Data System (ADS)

    Peddinti, S. R.; Kbvn, D. P.; Ranjan, S.; Suradhaniwar, S.; J, P. A.; R M, G.

    2015-12-01

    Vidarbha region in Maharashtra, India (home for mandarin Orange) experience severe climatic uncertainties resulting in crop failure. Phytopthora are the soil-borne fungal species that accumulate in the presence of moisture, and attack the root / trunk system of Orange trees at any stage. A scientific understanding of soil-moisture-disease relations within the active root zone under different climatic, irrigation, and crop cycle conditions can help in practicing management activities for improved crop yield. In this study, we developed a protocol for performing 3-D time-lapse electrical resistivity tomography (ERT) at micro scale resolution to monitor the changes in resistivity distribution within the root zone of Orange trees. A total of 40 electrodes, forming a grid of 3.5 m x 2 m around each Orange tree were used in ERT survey with gradient and Wenner configurations. A laboratory test on un-disturbed soil samples of the region was performed to plot the variation of electrical conductivity with saturation. Curve fitting techniques were applied to get the modified Archie's model parameters. The calibrated model was further applied to generate the 3-D soil moisture profiles of the study area. The point estimates of soil moisture were validated using TDR probe measurements at 3 different depths (10, 20, and 40 cm) near to the root zone. In order to understand the effect of soil-water relations on plant-disease relations, we performed ERT analysis at two locations, one at healthy and other at Phytopthora affected Orange tree during the crop cycle, under dry and irrigated conditions. The degree to which an Orange tree is affected by Phytopthora under each condition is evaluated using 'grading scale' approach following visual inspection of the canopy features. Spatial-temporal distribution of moisture profiles is co-related with grading scales to comment on the effect of climatic and irrigation scenarios on the degree and intensity of crop disease caused by Phytopthora.

  14. 77 FR 30497 - Submission for OMB Review; Comment Request

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-23

    ... Hours: 308. Animal and Plant Health Inspection Service Title: Citrus Greening and Asian Citrus Psyllid... Psyllid (ACP)'' (Sec. Sec. 301.76 through 301.76-11). Citrus greening, also known as Huanglonghing disease..., suppress, control, prevent, or retard the spread of plant pests (such as citrus canker) new or...

  15. 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...

  16. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-06

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

  19. 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 ...

  20. 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

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

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

  2. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

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

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  4. New Pseudomonas spp. Are Pathogenic to Citrus

    PubMed Central

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

    2016-01-01

    Five putative novel Pseudomonas species shown to be pathogenic to citrus have been characterized in a screening of 126 Pseudomonas strains isolated from diseased citrus leaves and stems in northern Iran. The 126 strains were studied using a polyphasic approach that included phenotypic characterizations and phylogenetic multilocus sequence analysis. The pathogenicity of these strains against 3 cultivars of citrus is demonstrated in greenhouse and field studies. The strains were initially grouped phenotypically and by their partial rpoD gene sequences into 11 coherent groups in the Pseudomonas fluorescens phylogenetic lineage. Fifty-three strains that are representatives of the 11 groups were selected and analyzed by partial sequencing of their 16S rRNA and gyrB genes. The individual and concatenated partial sequences of the three genes were used to construct the corresponding phylogenetic trees. The majority of the strains were identified at the species level: P. lurida (5 strains), P. monteilii (2 strains), P. moraviensis (1 strain), P. orientalis (16 strains), P. simiae (7 strains), P. syringae (46 strains, distributed phylogenetically in at least 5 pathovars), and P. viridiflava (2 strains). This is the first report of pathogenicity on citrus of P. orientalis, P. simiae, P. lurida, P. moraviensis and P. monteilii strains. The remaining 47 strains that could not be identified at the species level are considered representatives of at least 5 putative novel Pseudomonas species that are not yet described. PMID:26919540

  5. New Pseudomonas spp. Are Pathogenic to Citrus.

    PubMed

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

    2016-01-01

    Five putative novel Pseudomonas species shown to be pathogenic to citrus have been characterized in a screening of 126 Pseudomonas strains isolated from diseased citrus leaves and stems in northern Iran. The 126 strains were studied using a polyphasic approach that included phenotypic characterizations and phylogenetic multilocus sequence analysis. The pathogenicity of these strains against 3 cultivars of citrus is demonstrated in greenhouse and field studies. The strains were initially grouped phenotypically and by their partial rpoD gene sequences into 11 coherent groups in the Pseudomonas fluorescens phylogenetic lineage. Fifty-three strains that are representatives of the 11 groups were selected and analyzed by partial sequencing of their 16S rRNA and gyrB genes. The individual and concatenated partial sequences of the three genes were used to construct the corresponding phylogenetic trees. The majority of the strains were identified at the species level: P. lurida (5 strains), P. monteilii (2 strains), P. moraviensis (1 strain), P. orientalis (16 strains), P. simiae (7 strains), P. syringae (46 strains, distributed phylogenetically in at least 5 pathovars), and P. viridiflava (2 strains). This is the first report of pathogenicity on citrus of P. orientalis, P. simiae, P. lurida, P. moraviensis and P. monteilii strains. The remaining 47 strains that could not be identified at the species level are considered representatives of at least 5 putative novel Pseudomonas species that are not yet described. PMID:26919540

  6. 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 ...

  7. 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...

  8. 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 ...

  9. Biological control of Asian citrus psyllid (Diaphorina citri) in Florida by the parasitoid Tamarixia radiata in urban plantings of orange jasmine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid is an important invasive citrus pest in the United States because it vectors a bacterium responsible for a devastating disease of citrus known as huanglongbing. A parasitoid of the psyllid, Tamarixia radiata (Hymenoptera: Eulophidae), was imported from Southeast Asia and re...

  10. Visualization of ‘Candidatus Liberibacter asiaticus’ cells in citrus seed coats with fluorescence in situ hybridization and transmission electron microscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Candidatus Liberibacter asiaticus’ is bacterium implicated as the causal agent of the economically damaging disease of citrus called huanglongbing (HLB). The bacterium is spread by movement of infected citrus propagation material and by the Asian citrus psyllid, Diaphorina citri Kuwayama. Seed tr...

  11. 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...

  12. 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...

  13. Cellular automata model for citrus variegated chlorosis.

    PubMed

    Martins, M L; Ceotto, G; Alves, S G; Bufon, C C; 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. PMID:11102058

  14. Transmission Rates of ‘Ca. Liberibacter asiaticus’ by Asian Citrus Psyllid Are Enhanced by the Presence and Developmental Stage of Citrus Flush.

    PubMed

    Hall, David G; Albrecht, Ute; Bowman, Kim D

    2016-04-01

    Asian citrus psyllid (Diaphorina citri Kuwayama) transmits a bacterium ‘Candidatus Liberibacter asiaticus’ (CLas) putatively responsible for a devastating citrus disease known as Asiatic huanglongbing (HLB) (citrus greening disease). The psyllid and disease have invaded many citrus-growing regions including the United States, where the disease is seriously jeopardizing the Florida citrus industry. We recently concluded research that showed CLas transmission rates are increased when citrus flush is present. Flush is any new leaf growth ranging in development from first emergence up until the leaves are fully expanded yet still tender. In an experiment with seedlings of a rootstock cultivar ‘US-942’, a 1-wk infestation of 20 Asian citrus psyllids from an infected colony resulted in 53–60% of seedlings becoming infected when flush was present compared with only 7% when no flush was present. In a second experiment with ‘US-942’, 77–97% of seedlings became infected when flush was present compared with 40% when no flush was present. A similar experiment with ‘Valencia’ sweet orange resulted in 23, 80, and 3% seedlings becoming infected when young, older, or no flush was present, respectively. Young plants are therefore more likely to contract HLB if flush is present, with older flush promoting higher infection rates under the conditions of this study. Based on this finding, healthy citrus should be protected from Asian citrus psyllid infestations throughout a flush. To evaluate germplasm for CLas resistance, inoculations using infected Asian citrus psyllid would best be achieved if flush is present. PMID:26884596

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

    PubMed

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

    2015-01-01

    Huanglongbing (HLB) is the most serious disease affecting the citrus industry worldwide to date. The causal agent, Candidatus Liberibacter asiaticus (Las), resides in citrus phloem, which makes it difficult to effectively treat with chemical compounds. In this study, a transcuticular nanoemulsion formulation was developed to enhance the permeation of an effective antimicrobial compound (ampicillin; Amp) against HLB disease through the citrus cuticle into the phloem via a foliar spray. The results demonstrated that efficiency of cuticle isolation using an enzymatic method (pectinase and cellulase) was dependent on the citrus cultivar and Las-infection, and it was more difficult to isolate cuticles from valencia orange (Citrus sinensis) and HLB-symptomatic leaves. Of eight adjuvants tested, Brij 35 provided the greatest increase in permeability of the HLB-affected cuticle with a 3.33-fold enhancement of cuticular permeability over water control. An in vitro assay using Bacillus subtilis showed that nanoemulsion formulations containing Amp (droplets size = 5.26 ± 0.04 nm and 94 ± 1.48 nm) coupled with Brij 35 resulted in greater inhibitory zone diameters (5.75 mm and 6.66 mm) compared to those of Brij 35 (4.34 mm) and Amp solution (2.83 mm) alone. Furthermore, the nanoemulsion formulations eliminated Las bacteria in HLB-affected citrus in planta more efficiently than controls. Our study shows that a water in oil (W/O) nanoemulsion formulation may provide a useful model for the effective delivery of chemical compounds into citrus phloem via a foliar spray for controlling citrus HLB. PMID:26207823

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

    PubMed Central

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

    2015-01-01

    Huanglongbing (HLB) is the most serious disease affecting the citrus industry worldwide to date. The causal agent, Candidatus Liberibacter asiaticus (Las), resides in citrus phloem, which makes it difficult to effectively treat with chemical compounds. In this study, a transcuticular nanoemulsion formulation was developed to enhance the permeation of an effective antimicrobial compound (ampicillin; Amp) against HLB disease through the citrus cuticle into the phloem via a foliar spray. The results demonstrated that efficiency of cuticle isolation using an enzymatic method (pectinase and cellulase) was dependent on the citrus cultivar and Las-infection, and it was more difficult to isolate cuticles from valencia orange (Citrus sinensis) and HLB-symptomatic leaves. Of eight adjuvants tested, Brij 35 provided the greatest increase in permeability of the HLB-affected cuticle with a 3.33-fold enhancement of cuticular permeability over water control. An in vitro assay using Bacillus subtilis showed that nanoemulsion formulations containing Amp (droplets size = 5.26 ± 0.04 nm and 94 ± 1.48 nm) coupled with Brij 35 resulted in greater inhibitory zone diameters (5.75 mm and 6.66 mm) compared to those of Brij 35 (4.34 mm) and Amp solution (2.83 mm) alone. Furthermore, the nanoemulsion formulations eliminated Las bacteria in HLB-affected citrus in planta more efficiently than controls. Our study shows that a water in oil (W/O) nanoemulsion formulation may provide a useful model for the effective delivery of chemical compounds into citrus phloem via a foliar spray for controlling citrus HLB. PMID:26207823

  17. 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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asian citrus psyllid (Diaphorina citri) transmits the causal agent of Huanglongbing, a devastating disease of citrus trees. In this study, we measured behavioral responses of D. citri to combinations of visual, olfactory, and gustatory stimuli in test arenas. Stimuli were presented to the psyllids ...

  19. 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...

  20. 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...

  1. 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 ...

  2. 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...

  3. 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...

  4. HLB resistance and tolerance in citrus scion development at the U.S. Horticultural Research Laboratory

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is severely impacting Florida citrus and threatening industries in the rest of the United States. Productivity declines in many HLB-affected trees. Fruit size and quality often diminish as the disease advances. The USDA citrus scion breeding program is charged with producing impr...

  5. Midgut gene expression in Asian citrus psyllid (Hemiptera: Psyllidae) Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We produced a gene expression dataset from the midgut tissues of the Asian citrus psyllid (AsCP), Diaphorina citri (Hemiptera: Psyllidae). The AsCP is the primary vector of the bacterium associated with a devastating citrus disease known as huanglongbing (HLB). The occurrence and spread of the AsCP ...

  6. Transmission and Propagation of ‘Candidatus Liberibacter asiaticus’ by Grafting with Individual Citrus Leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a chronic, progressive decline disease in citrus associated with systemic infection by the bacterium Candidatus Liberibacter asiaticus (CLas). Transmission in the field is by the Asian citrus psyllid (ACP), Diaphorina citri, Kuwayama. Experimental propagation of CLas is done c...

  7. Vibrational duetting mimics to trap and disrupt mating of the devastating Asian citrus psyllid insect pest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP) is the primary vector of a bacterium that produces a devastating disease of citrus, huanglongbing. Efficient surveillance of ACP at low population densities is essential for timely pest management programs. ACP males search for mates on tree branches by producing vibra...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  9. 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...

  10. 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...

  11. 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...

  12. Cryopreservation of Citrus seeds via dehydration and direct immersion in liquid nitrogen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus germplasm is conventionally conserved in clonal orchards and greenhouses, where it is subjected to potential losses due to pests, diseases and climatic hazards. In recent years, many studies reported preservation of germplasm in the genus Citrus. As a result, effective freezing protocols have...

  13. Heat treatment eliminates ‘Candidatus Liberibacter asiaticus’ from infected citrus trees under controlled conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) is one of the most destructive diseases of citrus worldwide. The causal agents of HLB are three species of a-proteobacteria, ‘Candidatus Liberibacter asiaticus’ (Las), ‘Ca. Liberibacter africanus’ and ‘Ca. Liberibacter americanus’. Previous studies have found distinct va...

  14. 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...

  15. 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...

  16. Metabolic variations in different citrus rootstock cultivars associated with different responses to Huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is one of the most destructive bacterial diseases of citrus. No resistant cultivars have been identified, although tolerance has been observed in the genus Poncirus and some of its hybrids with Citrus that are commonly used as rootstocks. In this study we exploited this tolerance...

  17. Vibrational duetting mimics to trap and disrupt mating of the devasting Asian citrus psyllid insect pest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian citrus psyllid (ACP) is the primary vector of a bacterium that produces a devastating disease of citrus, huanglongbing. Efficient surveillance of ACP at low population densities is essential for timely pest management programs. ACP males search for mates on tree branches by producing vibra...

  18. Viability of ‘Candidatus Liberibacter asiaticus’ prolonged by addition of citrus juice to culture medium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing, or citrus greening disease, is associated with infection by the phloem-limited bacterium ‘Candidatus Liberibacter asiaticus’ (LAS). Infection with LAS, vectored by the Asian citrus psyllid (Diaphorina citri), is incurable; therefore, knowledge regarding LAS biology and pathogenesis is...

  19. Background and initial evaluations of recently introduced cultivars distributed by the Citrus Clonal Protection Program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Each year the Citrus Clonal Protection Program (CCPP) distributes budwood of new, potentially important commercial citrus cultivars as they are re- leased from quarantine after completing a thorough “Variety Introduction (VI)” disease testing and therapy program. This article is the second in a seri...

  20. 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...

  1. 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...

  2. 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...

  3. Characterization of Pear Blister Canker Viroid Isolates from Australian Pome Fruit Orchards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pear blister canker viroid (PBCVd) was detected in pear (Pyrus sp.), nashi (Pyrus serotina) and quince (Cydonia oblonga) trees from various pome fruit growing regions of Australia using dot-blot hybridization and RT-PCR techniques. Characteristic symptoms of PBCVd infection were not observed on the...

  4. 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 ...

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

    Yan, Huaxue; Zeng, Jiwu; Zhong, Guangyan

    2015-07-01

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

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

    PubMed Central

    Mallick, Neelam; Khan, Rafeeq Alam

    2016-01-01

    Objective: Hyperlipidemia, extensively contributes in the progression of coronary heart diseases and atherosclerosis, but may be managed through alterations in the nutritional pattern. Several studies show that diet rich in polyphenols and antioxidants have antiatherogenic effects. Citrus sinensis and Citrus paradisi are widely known for health benefits and have found to produce antioxidant, anti-inflammatory, and hypolipidemic effects, hence current research was planned to determine the hypolipidemic effects of C. sinensis and C. paradisi in rats receiving diet rich in cholesterol. Materials and Methods: All rats were divided into 11 groups each comprising 10 animals: Normal control group and hyperlipidemic control. C. sinensis treated three groups, C. paradisi treated three groups, C. sinensis and C. paradisi combination treated two groups, and group treated atorvastatin. All rats in the respective groups were treated orally with sterile water, juices, and standard drug for 8 weeks and lipid profile was estimated at the end of dosing. Results: Cholesterol, triglycerides (TGs), and low-density lipoprotein (LDL) were decreased at all the three doses of C. sinensis and C. paradisi but rise in high-density lipoprotein (HDL) was only significant at 8 ml/kg, and 0.3 ml/kg, respectively. Animals received the combination doses of C. sinensis and C. paradisi also showed a highly significant fall in cholesterol, LDL, and TGs, however HDL level was significantly elevated by SPJ-2 combination. Conclusion: Results suggest that C. sinensis and C. paradisi possess antihyperlipidemic activity due to phytochemicals and other essential nutrients, hence may serve as cardioprotective by preventing thrombosis. PMID:27134462

  9. 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 ...

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

    PubMed

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

    2016-04-01

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

  11. 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…

  12. 7 CFR 301.76-3 - Quarantined areas; citrus greening and Asian citrus psyllid.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  13. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  14. 7 CFR 301.76-2 - Regulated articles for Asian citrus psyllid and citrus greening.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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

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

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  16. Transcriptome analysis of sweet orange trees infected with ‘Candidatus Liberibacter asiaticus’ and two strains of citrus tristeza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) and tristeza, are diseases of citrus caused by a member of the a-proteobacteria, ‘Candidatus Liberibacter asiaticus’ (CaLas), and Citrus tristeza virus (CTV) respectively. HLB is a devastating disease, but CTV strains vary from very severe to very mild. Both CaLas and CTV are p...

  17. 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...

  18. Effect of drought and defoliation on the susceptibility of eucalypts to cankers caused by Endothia gyrosa and Botryosphaeria ribis

    SciTech Connect

    Old, K.M.; Gibbs, R.; Craig, I.; Myers, B.J. ); Yuan, Z.Q. )

    1990-01-01

    Seedlings, saplings and mature eucalypts were susceptible to infection by Endothia gyrosa and Botryosphaeria ribis. Eucalyptus regnans and E. delegatensis were more susceptible than E. grandis and E. saligna. In trees not subjected to stress, cankers were limited in extent and often healed. When trees were defoliated, either manually or by severe insect attack, stem concentrations of both starch and soluble carbohydrates were reduced and canker development in some pathogen/host combinations was increased. Seedlings subjected to water stress were not predisposed to canker formation. The association of E. gyrosa with branch dieback of rural eucalypts suffering from chronic defoliation suggests that canker fungi contribute to the crown dieback syndrome in south-eastern Australia.

  19. 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

  20. 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...

  1. Phytosanitary Status of California Citrus

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  2. Widespread applications of citrus cryopreservation

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  3. The effect of a minor constituent of essential oil from Citrus aurantium: the role of β-myrcene in preventing peptic ulcer disease.

    PubMed

    Bonamin, Flavia; Moraes, Thiago M; Dos Santos, Raquel C; Kushima, Hélio; Faria, Felipe M; Silva, Marcos A; Junior, Ivan V; Nogueira, Leonardo; Bauab, Tais M; Souza Brito, Alba R M; da Rocha, Lucia R M; Hiruma-Lima, Clélia A

    2014-04-01

    The monoterpene β-myrcene has been widely used in cosmetics, food and beverages, and it is normally found in essential oil from citrus fruit. The aim of this study was to investigate the anti-ulcer effects of β-myrcene on experimental models of ulcers that are induced by ethanol, NSAIDs (non-steroidal anti-inflammatory drugs), stress, Helicobacter pylori, ischaemia-reperfusion injury (I/R) and cysteamine in order to compare with the essential oil of Citrus aurantium and its major compound limonene. The results indicate that the oral administration of β-myrcene at a dose of 7.50mg/kg has important anti-ulcer activity with significantly decreased gastric and duodenal lesions as well as increased gastric mucus production. The results showed treatment with β-myrcene caused a significant increase in mucosal malondialdehyde level (MDA), an important index of oxidative tissue damage. The β-myrcene was also endowed with marked enhancement of antioxidant enzyme activity from GR system as evidenced by the decreased activity of superoxide dismutase (SOD) and increased levels of glutathione peroxidase (GPx), glutathione reductase (GR), and total glutathione in gastric tissue. Our results also shown that treatment with β-myrcene is not involved with thioredoxin reductase (TrxR) activity. Our results reveal, for the first time, the importance of β-myrcene as an inhibitor of gastric and duodenal ulcers and demonstrate that an increase in the levels of gastric mucosa defence factors is involved in the anti-ulcer activity of β-myrcene. PMID:24480520

  4. Influence of citrus source and test genotypes on inoculations with Candidatus Liberibacter asiaticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Assessments of the resistance of citrus germplasm to huanglongbing (HLB) can be expedited by inoculating plants under laboratory or greenhouse settings with the Huanglonbing bacterium, Candidatus Liberibacter asiaticus (CLas). Consistent rapid screening is critical to efficiently assess disease resi...

  5. Other fungal diseases of chickpea and lentil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are about 20 fungal diseases of chickpea and lentil that have very little information available. These diseases may not cause significant damage or may cause damage at specific and limited locales. Examples of these diseases include Cylindrosporium leaf spot and stem canker, Ozonium wilt and...

  6. Draft Genome Sequence of Erwinia billingiae OSU19-1, Isolated from a Pear Tree Canker

    PubMed Central

    Klein, Jeannie M.; Bennett, Rhett W.; MacFarland, Logan; Abranches Da Silva, Megan E.; Meza-Turner, Britney M.; Dark, Phillip M.; Frey, Mackenzie E.; Wellappili, Dulani P.; Beugli, Aron D.; Jue, Holman J.; Mellander, Joshua M.; Wei, Wei

    2015-01-01

    Plant-associated Erwinia include pathogenic and nonpathogenic species. We report the 5.6-Mb genome sequence of Erwinia billingiae OSU19-1, isolated from a canker on a pear tree inoculated with Erwinia amylovora. OSU19-1 and a closely related European isolate, E. billingiae Eb661T, share many similarities including 40 kb of plasmid sequence. PMID:26430039

  7. 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...

  8. Phyllocnistis citrella

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The citrus leafminer, Phyllocnistis citrella, is a global pest of citrus. Damage is caused by larval mining of the leaves that reduces photosynthetic capacity of the leaves and predisposes the wounded leaf to infection by the bacterium that causes citrus canker disease. This entry in the encylopedia...

  9. 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

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

    PubMed

    Killiny, Nabil; Hijaz, Faraj

    2016-04-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  12. 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...

  13. Five new citrus rootstocks with improved tolerance to huanglongbing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Five new citrus rootstocks, US-1279, US-1281, US-1282, US-1283, and US-1284 were released by the Agricultural Research Service in September 2014 for commercial use in areas threatened by huanglongbing disease. These rootstock selections originated from 1995 crosses of mandarins × Trifoliate Orange. ...

  14. 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%.

  15. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  18. Molecular Analysis Among MCA13-reactive Isolates Reveals a Strategy for Rapid Assessment of Citrus tristeza Virus Severity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) genotypes vary in disease severity ranging from symptomless to virulent (stem pitting) in commercial citrus plantings. Because CTV is spread by propagation and by aphid vectors, rapid identification and virulence typing are critical for control and interdiction activitie...

  19. Changes in free polyphenol levels in Satsuma leaves in response to Asian citrus psyllid infestation and water stress

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB), also referred to as citrus greening disease has caused significant losses to the citrus industry in the United States and elsewhere. In our previous studies, we observed the fluctuation of some primary and secondary metabolites in response to biotic (psyllid feeding) and abiotic...

  20. Transcriptional responses and carbohydrate metabolism of citrus infected with Candidatus Liberibacter asiaticus, the causal agent of Huanglongbing in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Huanglongbing (HLB) is a devastating disease of citrus occurring in most citrus growing regions worldwide. It is caused by a phloem-limited, fastidious bacterium of the genus Candidatus Liberibacter, which is transmitted through insect vectors. HLB causes the decline of trees within few years afte...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  2. 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...

  3. 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...

  4. 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...

  5. Differential stylet penetration behaviors of two Aphis gossypii biotypes in relation to host or vector infection with Citrus tristeza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus tristeza virus (CTV) is one of the most important citrus disease agents worldwide. The impact of CTV on American agriculture has been significant, affecting 50 million trees with economic losses of several hundred million dollars. In California, this virus is predominantly transmitted by tw...

  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. 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...

  8. 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,...

  9. 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

  10. Guide to managing vineyard trunk diseases in Lodi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    All vineyards in California are likely to become infected with trunk diseases (a.k.a. wood-canker diseases). The main trunk diseases are Botryosphaeria dieback, Esca, Eutypa dieback, and Phomopsis dieback. The infections are chronic and accumulate over time. Farming vines with trunk diseases becomes...

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

    PubMed

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

    2016-06-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  13. Citrus tristeza virus: making an ally from an enemy.

    PubMed

    Dawson, William O; Bar-Joseph, Moshe; Garnsey, Stephen M; Moreno, Pedro

    2015-01-01

    Virus diseases of perennial trees and vines have characteristics not amenable to study using small model annual plants. Unique disease symptoms such as graft incompatibilities and stem pitting cause considerable crop losses. Also, viruses in these long-living plants tend to accumulate complex populations of viruses and strains. Considerable progress has been made in understanding the biology and genetics of Citrus tristeza virus (CTV) and in developing it into a tool for crop protection and improvement. The diseases in tree and vine crops have commonalities for which CTV can be used to develop a baseline. The purpose of this review is to provide a necessary background of systems and reagents developed for CTV that can be used for continued progress in this area and to point out the value of the CTV-citrus system in answering important questions on plant-virus interactions and developing new methods for controlling plant diseases. PMID:25973695

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

    PubMed

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

    2016-05-01

    Citrus bioflavonoids embrace a wide group of phenolic compounds effecting the production and scavenging of reactive oxygen species and the processes relating free radical-mediated injury. Keeping in view of the antioxidant and anti-inflammatory properties of Citrus sinensis and Citrus paradisi, present study was undertaken to explore the effects of C. sinensis (orange juice) and C. paradisi (grapefruit juice) at three different doses alone and their two combinations with the objective to examine the effects of these compounds in an experimental model of rat colitis induced by trinitrobenzenesulphonic acid (TNBS). Hence biochemical parameters e.g. myeloperoxidase, alkaline phosphatase, C-reactive protein (CRP) and glutathione were assessed. Data entry and analysis was accomplished by Statistical Package for the Social Sciences version 17 and was presented as mean ± S.E.M with 95% confidence interval. Present result shows that these juices, mainly C. paradisi, may be efficacious for the management of inflammatory bowel disease. In acute colitis model, C. paradise encouraged a decrease in the extension of the lesion escorted by a decrease in the occurrence of diarrhea and reinstatement of the glutathione content. Related effects were produced by the administration of C. sinensis, which also prevented the myeloperoxidase and alkaline phosphatase actions in acute intestinal inflammatory process. The effect of the citrus juices on the inflammatory process may be associated to their antioxidant and anti-inflammatory properties, as revealed in present investigation. The favorable effects exerted were demonstrated both by histological and biochemical changes and were related with a progress in the colonic oxidative status. PMID:27166529

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The xylem-limited, Gram-negative, fastidious plant bacterium Xylella fastidiosa is the causal agent of citrus variegated chlorosis (CVC), a destructive disease affecting approximately half of the citrus plantations in the State of São Paulo, Brazil. The disease was recently found in Central America...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

  3. Effect of Lime on Criconemella xenoplax and Bacterial Canker in Two California Orchards

    PubMed Central

    Underwood, T.; Jaffee, B. A.; Verdegaal, P.; Norton, M. V. K.; Asai, W. K.; Muldoon, A. E.; McKenry, M. V.; Ferris, H.

    1994-01-01

    In a peach orchard with an initial soil pH of 4.9, preplant application of 0, 13.2, 18.2, 27.3, or 54.2 kg lime/tree site altered soil pH (range after 1 year = 4.8-7.3) but did not affect numbers of Criconemella xenoplax or tree circumference. Liming also failed to reduce the incidence of bacterial canker, which affected 17% of the trees by the sixth year after planting. Four years after planting, numbers of C. xenoplax exceeded 400/100 cm³ soil, regardless of treatment. Trees with higher densities of C. xenoplax had a higher incidence of canker. The nematophagous fungus Hirsutella rhossiliensis was not detected until the fourth year. Thereafter, the incidence of H. rhossiliensis and percentage C. xenoplax parasitized by H. rhossiliensis increased, but the increases lagged behind increases in numbers of nematodes. In an almond orchard with an initial soil pH of 4.6, preplant application of 0, 6.4, 12.8, or 25.0 kg lime/tree site altered soil pH (range after 1 year = 4.7-7.1). Numbers of C. xenoplax remained low (<20/100 cm³ soil), whereas numbers of Paratylenchus sp. increased to high levels (>500/100 cm³ soil), regardless of treatment. Low levels (<20/100 cm³ soil) of H. rhossiliensis -parasitized Paratylenchus sp. were detected. No bacterial canker occurred, but tree circumference was greater after 6 years if soil pH was intermediate (6.0-7.0). PMID:19279934

  4. Identification of Pseudomonas syringae pv. actinidiae strains causing bacterial canker of kiwifruit in the Anhui Province of China, and determination of their streptomycin sensitivities.

    PubMed

    Yang, X; Yi, X-K; Chen, Y; Zhang, A-F; Zhang, J-Y; Gao, Z-H; Qi, Y-J; Xu, Y-L

    2015-01-01

    Bacterial canker, caused by Pseudomonas syringae pv. actinidiae, is one of the most severe diseases of kiwifruit. It has become an international pandemic and threatens the sustainable development of kiwifruit production in all main kiwi-growing regions worldwide. Streptomycin has been the major bactericide for the control of kiwifruit canker, especially in Anhui Province, one of the main kiwifruit production regions in China. However, until now, no studies on the baseline sensitivity to streptomycin of field isolates of P. syringae pv. actinidiae from China have been available. During 2012-2013, a total of 102 single-colony P. syringae pv. actinidiae strains were isolated: 36, 12, 13, 26, and 15 strains from Yuexi, Jinzhai, Huoshan, Qianshan, and Taihu counties, respectively. All strains were confirmed by production of a 280-bp fragment using the specific primers PsaF1/R2 upon polymerase chain reaction amplification, followed by an assay for confirmation of pathogenicity to fulfill Koch's postulates. In this study, the streptomycin sensitivity of the 102 isolated strains was determined. The half-maximal effective concentration values for inhibition of growth by streptomycin were 0.03-0.42 μg/mL (average 0.12 ± 0.06 μg/mL). The baseline sensitivity curve was unimodal, representing range-of-variation factors of 14.0. No resistant subpopulation was identified among the strains used in the study. Thus, these sensitivity data could be used as a baseline for monitoring the shift in sensitivity of P. syringae pv. actinidiae populations to streptomycin in Anhui Province. Continuous resistance monitoring should be carried out, as streptomycin is an at-risk bactericide agent. PMID:26345745

  5. Guide to managing vineyard trunk diseases in Lodi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Trunk diseases (wood-canker diseases) threaten all California vineyards due to widespread distribution of the fungal pathogens. The infections are chronic and occur each year. Trunk diseases in mature vineyards reduce yields and increase management costs to the point where the vineyard is no longer ...

  6. 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...

  7. Identification Guide for Diseases of Tea (Camellia sinensis)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this guide on diseases associated with tea (Camellia sinensis) is to assist with p;roblem identification and raise awareness of serious plant disease pathogens not yet present in Hawaii. Blister bligtht, horse-hair blight, and twig dieback/stem canker are very destructive diseases fo...

  8. History and Diversity of Citrus leprosis virus Recorded in Herbarium Specimens.

    PubMed

    Hartung, John S; Roy, Avijit; Fu, Shimin; Shao, Jonathan; Schneider, William L; Brlansky, Ronald H

    2015-09-01

    Leprosis refers to two diseases of citrus that present similar necrotic local lesions, often surrounded by chlorotic haloes on citrus. Two distinct viruses are associated with this disease, one that produces particles primarily in the nucleus of infected plant cells (Citrus leprosis virus nuclear type [CiLV-N]; Dichorhavirus) and another type that produces particles in the cytoplasm of infected plant cells (Citrus leprosis virus cytoplasmic type [CiLV-C]; Cilevirus). Both forms are transmitted by Brevipalpid mites and have bipartite, single-stranded, RNA genomes. CiLV-C and CiLV-N are present in South and Central America and as far north as parts of Mexico. Although leprosis disease was originally described from Florida, it disappeared from there in the 1960s. The United States Department of Agriculture-Agricultural Research Service maintains preserved citrus specimens identified at inspection stations 50 or more years ago with symptoms of citrus leprosis. We isolated RNA from these samples and performed degradome sequencing. We obtained nearly full-length genome sequences of both a typical CiLV-C isolate intercepted from Argentina in 1967 and a distinct CiLV-N isolate obtained in Florida in 1948. The latter is a novel form of CiLV-N, not known to exist anywhere in the world today. We have also documented the previously unreported presence of CiLV-N in Mexico in the mid-20th century. PMID:25961338

  9. 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

  10. 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...

  11. Evaluation of citrus fibers as a tablet excipient.

    PubMed

    Cespi, Marco; Bonacucina, Giulia; Roberts, Matthew; Hanson, Samuel; Jones, Stephen; Makevica, Elina; Casettari, Luca; Palmieri, Giovanni Filippo

    2014-04-01

    The consumption of fibers is associated with many health benefits, such as a reduction of cardiovascular and gastrointestinal diseases, control of body weight, and prevention of diabetes. Despite the widespread use of fiber supplements such as capsules or tablets, there is an almost complete lack of information concerning the technological properties of functional fibers used in nutraceutical formulations. The aim of this work was to characterize the technological properties of citrus fibers necessary for their use as a processing aid in tableting. The results obtained showed that citrus fibers share many properties of other polysaccharides used as tableting excipients, such as thermal behavior and compaction mechanism, together with an appreciable tabletability. However, the most interesting properties resulted from their disintegration power. Citrus fibers behaved in a similar manner to the well-known super disintegrant croscarmellose sodium and resulted to be little susceptible to their concentration, to lubricant type, and lubricant concentration. Thus, this work supports the idea of a potential use of citrus fibers as "active" substances and processing aid in the tableting of nutraceutical products and also as functional excipient in pharmaceutical tablets formulation. PMID:24306677

  12. Gnomoniopsis smithogilvyi causes chestnut canker symptoms in Castanea sativa shoots in Switzerland.

    PubMed

    Pasche, Sabrina; Calmin, Gautier; Auderset, Guy; Crovadore, Julien; Pelleteret, Pegah; Mauch-Mani, Brigitte; Barja, François; Paul, Bernard; Jermini, Mauro; Lefort, François

    2016-02-01

    A screening of Castanea sativa scions for grafting for the presence of endophytes showed that the opportunistic fungal pathogen Gnomoniopsis smithogilvyi was the most abundant member of the endophytic flora. This fungus is known as a pathogen affecting chestnut fruits in Italy and Australia. Here, we present evidence that it causes cankers very similar to the ones due to Cryphonectria parasitica infection on twigs and scions of chestnut trees. We found natural infections of G. smithogilvyi in healthy grafted plants as well as in scions from chestnut trees. The identity of the fungus isolated from asymptomatic tissues was verified by applying Koch's postulates and corroborated by DNA sequencing of four different gene regions. In contrast to C. parasitica that appears on the bark as yellow to orange pycnidia, stromata and slimy twisted tendrils, G. smithogilvyi forms orange to red and black pycnidia, gray stromata and cream-colored to beige slimy twisted tendrils on the bark. These Swiss strains are closely related to G. smithogilvyi strains from Australia and from New Zealand, Gnomoniopsis sp. and Gnomoniopsis castanea from New Zealand, Italy, France and Switzerland. While the strains from Ticino are genetically very close to G. smithogilvyi and G. castanea from Italy, the differences between the strains from Ticino and Geneva suggest two different origins. The present study supports the hypothesis that a single species named G. smithogilvyi, which is known to be the agent of chestnut rot, also causes wood cankers on chestnut. PMID:26768710

  13. Citrus fruits as a treasure trove of active natural metabolites that potentially provide benefits for human health.

    PubMed

    Lv, Xinmiao; Zhao, Siyu; Ning, Zhangchi; Zeng, Honglian; Shu, Yisong; Tao, Ou; Xiao, Cheng; Lu, Cheng; Liu, Yuanyan

    2015-01-01

    Citrus fruits, which are cultivated worldwide, have been recognized as some of the most high-consumption fruits in terms of energy, nutrients and health supplements. What is more, a number of these fruits have been used as traditional medicinal herbs to cure diseases in several Asian countries. Numerous studies have focused on Citrus secondary metabolites as well as bioactivities and have been intended to develop new chemotherapeutic or complementary medicine in recent decades. Citrus-derived secondary metabolites, including flavonoids, alkaloids, limonoids, coumarins, carotenoids, phenolic acids and essential oils, are of vital importance to human health due to their active properties. These characteristics include anti-oxidative, anti-inflammatory, anti-cancer, as well as cardiovascular protective effects, neuroprotective effects, etc. This review summarizes the global distribution and taxonomy, numerous secondary metabolites and bioactivities of Citrus fruits to provide a reference for further study. Flavonoids as characteristic bioactive metabolites in Citrus fruits are mainly introduced. PMID:26705419

  14. “Ozone” – The New Nemesis of Canker Sore

    PubMed Central

    Reddy, R. Sudhakara; Nallakunta, Rajesh

    2015-01-01

    Background: Recurrent aphthous ulceration or recurrent aphthous stomatitis is one of the most debilitating and painful oral mucosal disease. This disease entity has no specific cause to occur and no proper laboratory procedures are present to elicit the diagnosis. The treatment options are largely palliative and aimed at reducing symptoms thereby improving patient’s oral condition. In the present study the subjects witnessed alleviation of clinical symptoms related to the aphthous ulceration. Aims and objectives: The aim of the study was to explore the effectiveness of ozonated oil in the treatment of recurrent aphthous ulcer and to compare with sessame oil in order to analyse the effectiveness between the two topical oil medications. Materials and Methods: A single-blinded placebo-controlled trial comprising of 30 subjects with recurrent aphthous ulcers were divided into Group 1, Group 2 and Group 3 with 10 subjects in each group was performed. Patients in Group 1 received ozonated oil, Group 2 received sesame oil and Group 3 received placebo. Treatment response was assessed by measures of pain reduction, ulcer duration on 2nd, 4th and 6th day. Data were analyzed using Wilcokson signed rank test and Friedman test. Results: Participants treated with ozonated oil showed significant reduction in ulcer size, erythema and also alleviated the ulcer pain on 4th day of evaluation when compared to sesame oil and placebo group. On 6th day subjects treated with ozonated oil and sesame oil showed significant reduction in ulcer size and erythema. No significant difference was observed in placebo group when compared with other two groups on subsequent 2nd, 4th and 6th day of evaluation. Conclusion: Ozonated oil and sessame oil, both showed similar effectiveness in relieving the ulcer pain. Ozone with its wide variety of inherent properties has proven to be choice of treatment in completely relieving the ulcer pain and ulcer size when compared with that of its counter

  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. 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.

  17. 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...

  18. 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

  19. 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.

  20. Inheritance and heritability of resistance to citrus leprosis.

    PubMed

    Bastianel, Marinês; de Oliveira, Antonio Carlos; Cristofani, Mariângela; Filho, Oliveiro Guerreiro; Freitas-Astúa, Juliana; Rodrigues, Vandeclei; Astúa-Monge, Gustavo; Machado, Marcos Antônio

    2006-10-01

    ABSTRACT The genetic inheritance of resistance to leprosis, the most important viral disease of citrus in Brazil, was characterized through the phenotypic assessment of 143 hybrids resulting from crosses between tangor 'Murcott' (Citrus sinensis x C. reticulata) and sweet orange 'Pêra' (C. sinensis), considered to be resistant and susceptible to the disease, respectively. All plants were grafted onto Rangpur lime (C. limonia) and inoculated with Citrus leprosis virus, cytoplasmic type through the infestation with viruliferous mites, Brevipalpus phoenicis. The experiments were arranged in a completely randomized block design with 10 replicates. Incidence and severity of the disease in leaves and stems as well as plant growth parameters (plant height and stem diameter) were recorded for 3 years after the infestation with the viruliferous mites. The average values of all variables were analyzed using principal component analysis, discriminant factorial analysis, estimation of the clonal repeatability coefficients, and frequency of the distributions of the average values for each measured variable. The principal component analysis resulted in the identification of at least two groups with resistance and susceptibility to leprosis, respectively. About 99% of all hybrids were correctly classified according to the discriminant factorial analysis. The broad-sense heritability coefficients for characteristics associated with incidence and severity of leprosis ranged from 0.88 to 0.96. The data suggest that the inheritance of resistance to leprosis may be controlled by only a few genes. PMID:18943497