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1

Citrus Canker: The Pathogen and Its Impact  

NSDL National Science Digital Library

This resource is a review article about the Citrus Canker, an introduced plant disease. The article contains detailed background and overview and includes information on (1) Citrus Canker strain diversity, identification, diagnosis and characterization; (2) the symptoms and infection Process; (3) the epidemiology; (4) the management for prevention and control of Citrus Canker; (5) and the social, political, and legal ramifications of regulatory policy.

Tim R. Gottwald (USDA;); James H. Graham (University of Florida;); Tim S. Schubert (Florida Department of Agriculture and Consumer Services;)

2002-08-12

2

Citrus Canker: Alternatives for Control  

NSDL National Science Digital Library

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

Linda Weinland (Edison College;Biology); Peter Woodruff (Champlain College;Biology); Margaret Waterman (Southeast Missouri State University;Biology); Ethel D. Stanley (Beloit College;Biology)

2006-05-20

3

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

PubMed Central

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.

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

4

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

PubMed Central

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

2014-01-01

5

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

NASA Astrophysics Data System (ADS)

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.

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

2008-05-01

6

Potential of Plant Extracts for Controlling Citrus Canker of Lime  

Microsoft Academic Search

Five plant extracts of Hibiscus subdariffa Linn., Psidium guajava Linn., Punica granatum Linn., Spondias pinnata (Linn.f.)Kurz, and Tamarindus indica Linn. were evaluated for control of canker disease on Citrus aurantifolia (lime) caused by Xanthomonas axonopodis pv. citri (XC) (synonym X. campestris pv. citri ) under greenhouse condition. Aqueous extracts of H. subdariffa, P. granatum, S. pinnata, and T. indica exhibited

Chalida Leksomboon; Niphone Thaveechai; Wichai Kositratana

7

Effect of citrus leaf-miner damage, mechanical damage and inoculum concentration on severity of symptoms of Asiatic citrus canker in Tahiti lime  

Microsoft Academic Search

Citriculture in São Paulo State, Brazil, is threatened by Asiatic citrus canker (Xanthomonas axonopodis pv. citri). The introduction of the Asian citrus leaf miner (Phyllocnistis citrella [CLM]) has resulted in an increase in the number of disease foci and has changed the spatial pattern of citrus canker symptomatic trees from strong aggregation to intermediate aggregation and random patterns. We evaluated

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

2007-01-01

8

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

PubMed

ABSTRACT The eradication of nonnative 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 citrus producing areas of the world including the United States, Brazil, and Australia. Various eradication attempts have been made on the disease but have been associated with significant social and economic costs due to the necessary removal of large numbers of host trees. In this paper, a spatially explicit stochastic simulation model of Asiatic citrus canker is introduced that describes an epidemic of the disease in a heterogeneous host landscape. We show that an optimum eradication strategy can be determined that minimizes the adverse costs associated with eradication. In particular, we show how the optimum strategy and its total cost depend on the topological arrangement of the host landscape. We discuss the implications of the results for invading plant disease epidemics in general and for historical and future eradication attempts on Asiatic citrus canker. PMID:19900003

Parnell, S; Gottwald, T R; van den Bosch, F; Gilligan, C A

2009-12-01

9

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

Microsoft Academic Search

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

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

2012-01-01

10

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

PubMed

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

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

2013-10-01

11

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

PubMed Central

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.

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

2014-01-01

12

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

PubMed Central

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.

Fu, Xing-Zheng; Liu, Ji-Hong

2013-01-01

13

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

Federal Register 2010, 2011, 2012, 2013

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

2013-10-24

14

[Study on a bacterial strain Bt8 for biocontrol against citrus bacterial canker].  

PubMed

Citrus bacterial canker is an important disease of Citrus species in China. The disease severely occurs especially in the coastal area. Integrated control system has been used for the control of the disease, in which chemotherapy plays an important role at present. The chemotherapy-dominant control system brought many problems to the environment, such as chemical residua in the products and induction of resistance to fungicide(s) by the pathogen. To solve these problems, an intensive study on biocontrol of citrus bacterial canker is needed. Isolations and characterizations of biocontrol agents are the basis for biocontrol of the disease. A bacterial strain Bt8 with strong inhibiting ability against Xanthomonas axonopodis pv. citri (Hasse) Vauterin, was isolated from citrus orchard soil in Nanning, China. The isolated bacterial strain was identified and characterized as Acinetobacter baumannii Bouvet et Grimont on the base of its morphology and 16S rDNA sequence analysis as well as physiological and biochemical characters. The inhibiting activity of the bacterium suspension against the pathogen was significantly influenced by environmental factors, such as temperatures, pHs and media. At temperatures of 18 degrees C to 33 degrees C, both the inhibiting activity of the bacterium suspension and the biomass of the bacterium increased with the increases of temperatures, suggesting that the influence of temperature on inhibiting activity of the bacterium suspension was in dependence on the bacterial biomass. In NA liquid medium of pH 10, the bacterium suspension showed the highest inhibiting activity against Xanthomonas axonopodis pv. citri, which was not in dependence on biomass of the bacterium. The bacterium suspension provided 55.2% inhibition against bacterial canker under greenhouse conditions. The results showed that Acinetobacter baumannii has potential as biocontrol agent against bacterial canker disease. Acinetobacter baumannii was reported as the pathogens infecting human and animals. The present study enriched the understanding on biological diversity in Acinetobacter baumannii to sciences. This is the first report on the isolation of Acinetobacter baumannii with strong inhibiting ability against plant pathogen. PMID:16736594

Tan, Xiao-Yan; Huang, Si-Liang; Ren, Jian-Guo; Yan, Wei-Hong; Cen, Zhen-Lu

2006-04-01

15

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

PubMed Central

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.

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

16

Environmental Condition and Cypress Canker Disease  

Microsoft Academic Search

Cypress canker by Seiridium cardinale (Wag.) Sutt. & Gibson is a disease particularly harmful for cypress trees in Tuscany where the land scape value of this species is very important. The paper reports on the relationship among S. cardinale and environmental factors that may influence the spreading of the fungus using GIS technology. The s tudy conduced in the neighbourhood

Matteo FEDUCCI; Nicola LUCHI

2007-01-01

17

74 FR 16097 - Citrus Canker; Interstate Movement of Regulated Nursery Stock From Quarantined Areas  

Federal Register 2010, 2011, 2012, 2013

...was based on their apparent resistance to citrus canker infection...regarding the strong biological resistance of calamondins and kumquats...displayed on a plastic or metal tag attached to the outside...high degree of biological resistance to Xcc that the...

2009-04-09

18

[Loquat canker: a new disease for Argentina].  

PubMed

A stem canker disease caused by Pseudomonas syringae pv. eriobotryae (Takimoto) Young, Dye y Wilkie on loquat (Eriobotrya Japonica [Thumb] Lindl) was recorded for the first time in Argentina. Symptoms of the disease appeared as dry stem cankers which in advanced stages surrounded the stems. Similar cankers were noticeable on leaves midribs. Seven bacterial strains were isolated from diseased loquats and their identification was based on disease symptoms, pathogenicity and cultural and biochemical characteristics. All strains were levan positive and gave a hypersensitive reaction on tobacco leaves. Neither arginine dehydrolase nor oxidase was detected in any of the strains which produced a diffusible green pigment on King B which fluoresced under UV light and a distinct diffusible brown pigment on King B, SPA and Tween 80 media within 5-7 days of incubation. Lipolysis of Tween 80 was also recorded. The symptoms observed in the field and obtained by experimental inoculations were similar to those induced by Pseudomonas syringae pv. eriobotryae in the original description of the disease. PMID:2102015

Alippi, A M; Alippi, H E

1990-01-01

19

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

PubMed Central

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.

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

2012-01-01

20

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

Microsoft Academic Search

The risk of introduction of Xanthomonas citri subsp. 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, are assumed to be a risk. However, there is little information relative to

T. Gottwald; J. Graham; C. Bock; G. Bonn; E. Civerolo; M. Irey; R. Leite; G. McCollum; P. Parker; J. Ramallo; T. Riley; T. Schubert; B. Stein; E. Taylor

2009-01-01

21

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

PubMed

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

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

2014-04-01

22

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

PubMed Central

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

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

2014-01-01

23

In order to prevent the spread of citrus diseases, it is essential that personnel and equipment working near or contacting any citrus plant material be decontaminated in accordance with Citrus Health Response Program rules, with an approved material, regardless of whether an infestation has been proven to exist. Risks of acquiring and dispersing citrus diseases such as citrus canker bacterial inoculum are greatest when diseased citrus plant material and surrounding vegetation are wet. Avoid any unnecessary contact with citrus  

Microsoft Academic Search

DECONTAMINATION OF PERSONNEL: All persons should disinfect hands, arms and any other parts of the body that have contacted citrus and surrounding vegetation, plus gloves and hats, and any clothing, shoes and small personal items (pen, hand lens, glasses, pocketknife, etc.) that have come in contact with risky plant material, using one of the following prescribed products in accordance with

H. Zep Foam San

2008-01-01

24

Spatial Pattern Analysis of Citrus Canker-Infected Plantings in S?o Paulo, Brazil, and Augmentation of Infection Elicited by the Asian Leafminer  

Microsoft Academic Search

Gottwald, T. R., Bassanezi, R. B., Amorim, L., and Bergamin-Filho, A. 2007. Spatial pattern analysis of citrus canker-infected plantings in São Paulo, Brazil, and augmentation of infection elicited by the Asian leafminer. Phytopathology 97:674-683. Eradication of Asiatic citrus canker (ACC) has become increasingly difficult over the last decade, following the introduction of the Asian leafminer into Brazil and Florida, which

T. R. Gottwald; R. B. Bassanezi; L. Amorim; A. Bergamin-Filho

2007-01-01

25

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

PubMed Central

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.

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

2013-01-01

26

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

PubMed

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 nm 10 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. PMID:18404192

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

2008-04-10

27

Overexpression of a citrus NDR1 ortholog increases disease resistance in Arabidopsis  

PubMed Central

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

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

2013-01-01

28

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

PubMed

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

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

2013-01-01

29

The ColR/ColS two-component system plays multiple roles in the pathogenicity of the citrus canker pathogen Xanthomonas citri subsp. citri.  

PubMed

Bacterial citrus canker disease, which is caused by Xanthomonas citri subsp. citri, is one of the most devastating diseases of citrus plants. In this study, we characterized the role of the two-component regulatory system ColR/ColS in the pathogenicity of X. citri subsp. citri. colS mutants (256A10 and 421E7), colR mutants (386C6 and 417E10), and a colR colS double mutant (306DSR) all lost pathogenicity and produced no symptoms on grapefruit leaves inoculated by either pressure infiltration or the spray method. The pathogenicity defect of the colS, colR, and colR colS mutants could be complemented using the wild-type colS, colR, and colR colS genes, respectively. Mutation of colS or colR significantly reduced X. citri subsp. citri growth in planta. The ColR/ColS system also played important roles in bacterial biofilm formation in glass tubes and on leaf surfaces, lipopolysaccharide (LPS) production, catalase activity, and tolerance of environmental stress, including phenol, copper, and hydrogen peroxide. Furthermore, quantitative reverse transcription-PCR assays demonstrated that the ColR/ColS system positively regulated the expression of important virulence genes, including hrpD6, hpaF, the O-antigen LPS synthesis gene rfbC, and the catalase gene katE. Overall, our data indicate that the two-component regulatory system ColR/ColS is critical for X. citri subsp. citri virulence, growth in planta, biofilm formation, catalase activity, LPS production, and resistance to environmental stress. PMID:21257774

Yan, Qing; Wang, Nian

2011-04-01

30

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

Federal Register 2010, 2011, 2012, 2013

...Movement of Regulated Nursery Stock and Fruit From Quarantined Areas...movement of regulated nursery stock and fruit from quarantined areas...APHIS-2013-0075, Regulatory Analysis and Development, PPD, APHIS...movement of regulated nursery stock and fruit from citrus...

2013-09-25

31

Density and distance-to-adult effects of a canker disease of trees in a moist tropical forest  

Microsoft Academic Search

We compared the spatial distribution of stem cankers on the canopy tree Ocotea whitei (Lauraceae) in a 20-ha plot on Barro Colorado Island, Panama, with spatial and temporal patterns of mortality in this host over the previous decade. The cankers occur both on adult and juvenile individuals, aothough juveniles are much more likely the adults to show symptoms. Disease incidence

G. S. Gilbert; R. B. Foster; S. P. Hubbell

1994-01-01

32

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

PubMed Central

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.

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

2012-01-01

33

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

PubMed

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

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

2012-01-01

34

Spatial pattern analysis of citrus canker-infected plantings in são paulo, Brazil, and augmentation of infection elicited by the asian leafminer.  

PubMed

ABSTRACT Eradication of Asiatic citrus canker (ACC) has become increasingly difficult over the last decade, following the introduction of the Asian leafminer into Brazil and Florida, which has led to changes in the eradication protocols. The present study, undertaken in Brazil, was aimed at characterizing the spatial patterns of ACC in commercial citrus plantings to gain better understanding of the dynamics of the disease subsequent to introduction of the leafminer. The spatial patterns of ACC were mapped in 326 commercial citrus plantings and statistically assessed at various spatial dimensions. The presence of "within-group" aggregation in each plot was examined via beta-binomial analysis for groups of trees parsed into three-by-three-tree quadrats. The relative intensity of aggregation was expressed as a binomial index of dispersion (D) and heterogeneity among plots expressed as the intracluster correlation coefficient, rho. The population of data sets was found to fall into three D categories, D < 1.3, 1.3 3.5. These categories then were related to other spatial characteristics. The binary form of Taylor's power law was used to assess the overdispersion of disease across plots and was highly significant. When the overall population of plots was parsed into D categories, the Taylor's R (2) improved in all cases. Although these methods assessed aggregation well, they do not give information on the number of foci or aggregations within each plot. Therefore, the number of foci per 1,000 trees was quantified and found to relate directly to the D categories. The lowest D category could be explained by a linear relationship of number of foci versus disease incidence, whereas the higher two categories were most easily explained by a generalized beta function for the same relationship. Spatial autocorrelation then was used to examine the spatial relationships "among groups" composed of three-by-three-tree quadrats and determine common distances between these groups of ACC-infected trees. Aggregation was found in >84% of cases at this spatial level and there was a direct relationship between increasing D category and increasing core cluster size, and aggregation at the among-group spatial hierarchy was generally stronger for the within-row than for the across-row orientation. Clusters of disease were estimated to average between 18 and 33 tree spaces apart, and the presence of multiple foci of infection was commonplace. The effectiveness of the eradication protocol of removing all "exposed" trees within 30 m surrounding each "ACC-infected tree" was examined, and the distance of subsequent infected trees beyond this 30-m zone from the original focal infected tree was measured for each plot. A frequency distribution was compiled over all plots to describe the distance that would have been needed to circumscribe all of these outliers as a theoretical alternative protocol to the 30-m eradication protocol. The frequency distribution was well described by a monomolecular model (R(2) = 0.98) and used to determine that 90, 95, and 99% of all newly infected trees occurred within 296, 396, and 623 m of prior-infected trees in commercial citrus plantings, respectively. These distances are very similar to previously reported distances determined for ACC in residential settings in Florida. PMID:18943598

Gottwald, T R; Bassanezi, R B; Amorim, L; Bergamin-Filho, A

2007-06-01

35

Identification of resistance to bacterial canker ( Pseudomonas syringae pv. syringae ) disease on apricot genotypes grown in Turkey  

Microsoft Academic Search

Bacterial canker caused by Pseudomonas syringae pv. syrinage (Pss) in apricot has widely spread in Turkey, especially in Malatya province, in recent years. The main objective of this\\u000a study was to determine resistance of apricot cultivars to bacterial canker caused by Pss in apricot cultivars grown in Turkey.\\u000a During the 2006–2007 growing period, bacterial isolations were taken from diseased apricot

M. Figen Donmez; Huseyin Karlidag; Ahmet Esitken

2010-01-01

36

Polymerase chain reaction-based detection of Fusarium circinatum, the causal agent of pitch canker disease.  

PubMed

Pitch canker is a highly damaging disease of Pinus radiata and the New Zealand forest industry is concerned by the potential impact of the disease, should it arrive, in New Zealand. To provide a rapid identification technique for this pathogen, a polymerase chain reaction-based diagnostic method has been developed. The method is able to detect the presence of the pathogen within infected host tissue, as well as infested soil and the reliability of the test has been estimated using Bayesian statistics. PMID:21586018

Ramsfield, T D; Dobbie, K; Dick, M A; Ball, R D

2008-11-01

37

Canker Sores  

MedlinePLUS

Canker sores are small, round sores on the inside of the cheek, under the tongue, or in the back of the throat. They usually have a red ... painful. They are not the same as cold sores, which are caused by herpes simplex. Canker sores ...

38

Symptom-based diagnosis of Huanglongbing (citrus greening) disease by PCR in sweet orange (Citrus sinensis Osbeck) and acid lime (Citrus aurantifolia Swingle)  

Microsoft Academic Search

Huanglongbing (HLB), previously known as citrus greening disease, is one of the most destructive diseases of citrus and responsible for the decline of citrus orchards in Andhra Pradesh (AP) and other citrus growing areas in the country. Polymerase chain reaction (PCR) amplification of 1160 bp fragment of 16S rDNA of HLB was observed in mottling symptoms, yellow vein symptoms, symptoms

K. Gopal; V. Gopi; L. Kalyani; M. Sreelatha; B. Sreenivasulu

2010-01-01

39

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

PubMed

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

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

2007-05-01

40

Diagnosis and Management of Certain Important Fungal Diseases of Citrus  

Microsoft Academic Search

Citrus is susceptible to a number of fungal pathogens causing incalculable losses to the crop. Occurrence of a particular\\u000a pathogen, its ability to cause disease, survival and subsequent spread to cross threshold level in order to damage the crop\\u000a are governed by agro-climatic conditions, varietal susceptibility, soil type etc. Among fungal diseases, the soil borne diseases\\u000a of Citrus are widespread

S. A. M. H. Naqvi

41

Citrus huanglongbing: a newly relevant disease presents unprecedented challenges.  

PubMed

Citrus huanglongbing (HLB) is one of the oldest citrus diseases and has been known for over a century. HLB is caused by 'Candidatus Liberibacter' spp. that are phloem-limited, fastidious ?-proteobacteria and infect hosts in different Kingdoms (i.e., Animalia and Plantae). When compared with well-characterized, cultivatable plant-pathogenic Gram-negative bacteria, the interactions of uncultured insect-vectored plant-pathogenic bacteria, including 'Ca. Liberibacter' spp., with their hosts remain poorly understood. 'Ca. Liberibacter' spp. have been known to cause HLB, which has been rapidly spreading worldwide, resulting in dramatic economic losses. HLB presents an unprecedented challenge to citrus production. In this review, we focus on the most recent research on citrus, 'Candidatus Liberibacter asiaticus', and psyllid interactions, specifically considering the following topics: evolutionary relationships among 'Ca. Liberibacter' spp., genetic diversity, host range, genome analysis, transmission, virulence mechanisms, and the ecological importance of HLB. Currently, no efficient management strategy is available to control HLB, although some promising progress has been made. Further studies are needed to understand citrus, 'Ca. L. asiaticus', and psyllid interactions to design innovative management strategies. Although HLB has been problematic for over a century, we can only win the battle against HLB with a coordinated and deliberate effort by the citrus industry, citrus growers, researchers, legislatures, and governments. PMID:23441969

Wang, Nian; Trivedi, Pankaj

2013-07-01

42

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

PubMed

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

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

2014-02-01

43

Alternative methods for the control of postharvest citrus diseases.  

PubMed

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

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

2014-07-01

44

Some new diseases of Citrus in Pakistan  

Microsoft Academic Search

Sweet orange (Citrus sinensis-(LINN.) OSBECK locally known as malta orange; mandarin and tangerines (C. reticulata BLANCO var. mandarin and var. tangerine); lemon (C. limon (LINN.)BURM. f.); Grapefruit (C. paradisi MACFAYDEN); Shaddock (C. decumana MURR.) vern. Chokotra; lime (C. auranti\\/olia SWIGLE); sour or bitter orange (C. aurantium LIN1;. sub. sp. amara LINN.) Sweet lime (C. auranti\\/olia SWtNGLE (= C. limetta RlSSO)

Abdul Hamid Khan

1959-01-01

45

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

PubMed

During a survey for pathogens of Florida torreya (Torreya taxifolia) in 2009, a novel Fusarium species was isolated from cankers affecting this critically endangered conifer whose current range is restricted to northern Florida and southwestern Georgia. Published multilocus molecular phylogenetic analyses indicated that this pathogen represented a genealogically exclusive, phylogenetically distinct species representing one of the earliest divergences within the Gibberella clade of Fusarium. Furthermore, completion of Koch's postulates established that this novel species was the causal agent of Florida torreya canker disease. Here we formally describe this pathogen as a new species, Fusarium torreyae. Pure cultures of this species produced long and slender multiseptate sporodochial conidia that showed morphological convergence with two distantly related fusaria, reflecting the homoplasious nature of Fusarium conidial morphology. PMID:23099517

Aoki, Takayuki; Smith, Jason A; Mount, Lacey L; Geiser, David M; O'Donnell, Kerry

2013-01-01

46

Citrus.  

PubMed

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

Orbovi?, Vladimir; Grosser, Jude W

2006-01-01

47

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

PubMed

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

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

48

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

PubMed

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

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

2011-04-01

49

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

Microsoft Academic Search

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

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

1988-01-01

50

Canker Sores (For Parents)  

MedlinePLUS

... up alone, but can also occur in small clusters. Sometimes an area will tingle or burn before ... using prescription vitamin supplements), immune system deficiencies, and food or other allergies. Back Continue Treatment Most canker ...

51

Transcriptome profiling of citrus fruit response to huanglongbing disease.  

PubMed

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

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

52

Transcriptome Profiling of Citrus Fruit Response to Huanglongbing Disease  

PubMed Central

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.

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

53

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

PubMed

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

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

2014-07-01

54

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

PubMed

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

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

2013-06-01

55

Citrus Genomics  

PubMed Central

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.

Talon, Manuel; Gmitter Jr., Fred G.

2008-01-01

56

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

PubMed

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

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

2013-02-01

57

Unexpected genetic diversity revealed in the Eucalyptus canker pathogen Teratosphaeria gauchensis  

Microsoft Academic Search

Teratosphaeria gauchensis causes a serious canker disease on Eucalyptus spp. in plantations in South America and Africa. The pathogen is closely related to, but distinct from T. zuluensis that causes a similar stem canker disease on Eucalyptus. The objective of this study was to use 10 previously developed polymorphic microsatellite markers to study the population\\u000a diversity of T. gauchensis, based

M. N. Cortinas; I. Barnes; B. D. Wingfield; M. J. Wingfield

58

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

PubMed

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

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

2013-07-01

59

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

60

World-wide importance of phoma stem canker ( Leptosphaeria maculans and L. biglobosa ) on oilseed rape ( Brassica napus )  

Microsoft Academic Search

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

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

61

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

Microsoft Academic Search

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

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

2006-01-01

62

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

PubMed

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

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

2014-02-01

63

Genetic Structure and Biology of Xylella fastidiosa Strains Causing Disease in Citrus and Coffee in Brazil?  

PubMed Central

Xylella fastidiosa is a vector-borne, plant-pathogenic bacterium that causes disease in citrus (citrus variegated chlorosis [CVC]) and coffee (coffee leaf scorch [CLS]) plants in Brazil. CVC and CLS occur sympatrically and share leafhopper vectors; thus, determining whether X. fastidiosa isolates can be dispersed from one crop to another and cause disease is of epidemiological importance. We sought to clarify the genetic and biological relationships between CVC- and CLS-causing X. fastidiosa isolates. We used cross-inoculation bioassays and microsatellite and multilocus sequence typing (MLST) approaches to determine the host range and genetic structure of 26 CVC and 20 CLS isolates collected from different regions in Brazil. Our results show that citrus and coffee X. fastidiosa isolates are biologically distinct. Cross-inoculation tests showed that isolates causing CVC and CLS in the field were able to colonize citrus and coffee plants, respectively, but not the other host, indicating biological isolation between the strains. The microsatellite analysis separated most X. fastidiosa populations tested on the basis of the host plant from which they were isolated. However, recombination among isolates was detected and a lack of congruency among phylogenetic trees was observed for the loci used in the MLST scheme. Altogether, our study indicates that CVC and CLS are caused by two biologically distinct strains of X. fastidiosa that have diverged but are genetically homogenized by frequent recombination.

Almeida, Rodrigo P. P.; Nascimento, Fernanda E.; Chau, John; Prado, Simone S.; Tsai, Chi-Wei; Lopes, Silvio A.; Lopes, Joao R. S.

2008-01-01

64

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

PubMed Central

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

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

2005-01-01

65

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

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

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

2014-04-20

66

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

PubMed Central

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

Zhao, Hongwei; Sun, Ruobai; Jin, Hailing

2013-01-01

67

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

PubMed

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

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

2013-03-01

68

Genetic variation and recombination of RdRp and HSP 70h genes of Citrus tristeza virus isolates from orange trees showing symptoms of citrus sudden death disease  

PubMed Central

Background Citrus sudden death (CSD), a disease that rapidly kills orange trees, is an emerging threat to the Brazilian citrus industry. Although the causal agent of CSD has not been definitively determined, based on the disease's distribution and symptomatology it is suspected that the agent may be a new strain of Citrus tristeza virus (CTV). CTV genetic variation was therefore assessed in two Brazilian orange trees displaying CSD symptoms and a third with more conventional CTV symptoms. Results A total of 286 RNA-dependent-RNA polymerase (RdRp) and 284 heat shock protein 70 homolog (HSP70h) gene fragments were determined for CTV variants infecting the three trees. It was discovered that, despite differences in symptomatology, the trees were all apparently coinfected with similar populations of divergent CTV variants. While mixed CTV infections are common, the genetic distance between the most divergent population members observed (24.1% for RdRp and 11.0% for HSP70h) was far greater than that in previously described mixed infections. Recombinants of five distinct RdRp lineages and three distinct HSP70h lineages were easily detectable but respectively accounted for only 5.9 and 11.9% of the RdRp and HSP70h gene fragments analysed and there was no evidence of an association between particular recombinant mosaics and CSD. Also, comparisons of CTV population structures indicated that the two most similar CTV populations were those of one of the trees with CSD and the tree without CSD. Conclusion We suggest that if CTV is the causal agent of CSD, it is most likely a subtle feature of population structures within mixed infections and not merely the presence (or absence) of a single CTV variant within these populations that triggers the disease.

Gomes, Clarissa PC; Nagata, Tatsuya; de Jesus, Waldir C; Neto, Carlos R Borges; Pappas, Georgios J; Martin, Darren P

2008-01-01

69

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

Federal Register 2010, 2011, 2012, 2013

...for the issuance of limited permits to move regulated nursery stock interstate, if...APHIS in order to ensure, among other things, that the nursery maintains records of...301.76-9 had provided, among other things, that all regulated nursery stock...

2011-04-27

70

Enhanced tomato resistance to bacterial canker by application of turtle oil  

Microsoft Academic Search

Pretreatment with oil of sea turtle Caretta caretta protected tomato plants against bacterial canker caused by Clavibacter michiganensis subsp. michiganensis (Cmm). The turtle oil was ineffective in inhibiting Cmm in an agar diffusion test, suggesting a mechanism of induced resistance. Under controlled conditions in the greenhouse, turtle oil lowered the disease index and had reduced the growth of bacteria up

Ömür Baysal; Y. Ziya Gürsoy; Hakan Örnek; Ahmet Duru

2005-01-01

71

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

Microsoft Academic Search

Intercontinental spread of emerging plant diseases is one of the most serious threats to world agriculture. One emerging disease is bacterial canker of kiwi fruit (Actinidia deliciosa and A. chinensis) caused by Pseudomonas syringae pv. actinidiae (PSA). The disease first occurred in China and Japan in the 1980s and in Korea and Italy in the 1990s. A more severe form

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

2012-01-01

72

Geographic variation in severity of phoma stem canker and Leptosphaeria maculans\\/ L. biglobosa populations on UK winter oilseed rape ( Brassica napus )  

Microsoft Academic Search

Phoma stem canker, caused by Leptosphaeria maculans and L. biglobosa, is the most important disease of oilseed rape in Europe. Differences between L. maculans and L. biglobosa in their life-cycles enable the two species to co-exist on oilseed rape crops over a cropping season. This review considers\\u000a the factors affecting geographic variation in the severity of phoma stem canker epidemics

Jenna F. Stonard; Akinwunmi O. Latunde-Dada; Yong-Ju Huang; Jonathan S. West; Neal Evans; Bruce D. L. Fitt

2010-01-01

73

Evaluation of Low-volume Sprayers Used in Asian Citrus Psyllid Control Applications.  

National Technical Information Service (NTIS)

The asian citrus psyllid Diaphorina citri (Sternorrhyncha: Psyllidae) is a detrimental pest to citrus (Citrus spp.) crops when it serves as a vector of the pathogen that causes greening (huanglongbing). Transmission of this disease causes mottling, chloro...

B. Fritz C. Hoffmann D. Martin R. Atwood T. Hurner

2010-01-01

74

Chemical composition and antimicrobial activity of Citrus essences on honeybee bacterial pathogen Paenibacillus larvae , the causal agent of American foulbrood  

Microsoft Academic Search

Antimicrobial properties and chemical composition of four citrus fruit essential oils to control Paenibacillus larvae, the causal agent of American foulbrood disease (AFB) were determined. This honeybee larvae disease occurs throughout the\\u000a world and is found in many beekeeping areas of Argentina. Citrus fruit essential oils tested were those from grapefruit (Citrus paradisi), sweet orange (Citrus sinensis), mandarin (Citrus nobilis)

Sandra R. Fuselli; Susana B. García de la Rosa; Martín J. Eguaras; Rosalía Fritz

2008-01-01

75

Mathematical modeling of citrus groves infected by huanglongbing.  

PubMed

Huanglongbing (citrus greening) is a bacterial disease that is significantly impacting the citrus industry in Florida and poses a risk to the remaining citrus-producing regions of the United States. A mathematical model of a grove infected by citrus greening is developed. An equilibrium stability analysis is presented. The basic reproductive number and its relation to the persistence of the disease is discussed. A numerical study is performed to illustrate the theoretical findings. PMID:23906145

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

2013-06-01

76

Citrus Greening Control Program in Florida Nurseries: Environmental Assessment, September 2005.  

National Technical Information Service (NTIS)

Citrus greening, or huanglongbing, is a bacterial disease that attacks the vascular system of plants. Once infected there is no cure for a tree with citrus greening disease. In areas of the world where citrus greening is endemic, citrus trees decline and ...

2005-01-01

77

Photographic remote sensing of sick citrus trees  

NASA Technical Reports Server (NTRS)

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.

Gausman, H. W.

1971-01-01

78

Citrus Inventory  

NASA Technical Reports Server (NTRS)

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.

1986-01-01

79

Citrus Inventory  

NASA Technical Reports Server (NTRS)

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.

1994-01-01

80

Citrus Leprosis Virus Vectored by Brevipalpus phoenicis (Acari: Tenuipalpidae) on Citrus in Brazil  

Microsoft Academic Search

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\\u000a of the disease include lesions on fruits, leaves, and twigs or small branches, causing premature fruit drop, defoliation,\\u000a and death of the twigs or

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

2003-01-01

81

Accumulation and availability of copper in citrus grove soils as affected by fungicide application  

Microsoft Academic Search

Purpose  Copper is a trace element of environmental concern. Repeated applications of Cu-containing fungicides have resulted in a large\\u000a scale of Cu contamination in agricultural soils. However, limited information is available regarding Cu accumulation and availability\\u000a in soils under citrus production in the Indian River Area, South Florida, which has received increasing amounts of Cu fungicides\\u000a to control canker and other

Jinghua Fan; Zhenli He; Lena Q. Ma; Peter J. Stoffella

2011-01-01

82

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

PubMed Central

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.

Cruz-Jaramillo, Jose Luis; Ruiz-Medrano, Roberto; Rojas-Morales, Lourdes; Lopez-Buenfil, Jose Abel; Morales-Galvan, Oscar; Chavarin-Palacio, Claudio; Ramirez-Pool, Jose Abrahan; Xoconostle-Cazares, Beatriz

2014-01-01

83

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

PubMed

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

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

84

Identification of QTLs associated with citrus resistance to Phytophthora gummosis  

Microsoft Academic Search

Citrus gummosis, caused byPhytophthora spp., is an important citrus disease in Brazil. Almost all citrus rootstock varieties are susceptible to it to some degree,\\u000a whereas resistance is present inPoncirus trifoliata, a closely related species. The objective of this study was to detect QTLs linked to citrusPhytophthora gummosis resistance. Eighty individuals of the F1 progeny, obtained by controlled crosses between Sunki

Amauri Siviero; Mariângela Cristofani; Edson L. Furtado; Antonio A. F. Garcia; Alexandre S. G. Coelho; Marcos A. Machado

2006-01-01

85

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

Microsoft Academic Search

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

Iqrar A. Khan; Jude W. Grosser

2004-01-01

86

The citrus fruit proteome: insights into citrus fruit metabolism.  

PubMed

Fruit development and ripening are key processes in the production of the phytonutrients that are essential for a balanced diet and for disease prevention. The pathways involved in these processes are unique to plants and vary between species. Climacteric fruit ripening, especially in tomato, has been extensively studied; yet, ripening of non-climacteric fruit is poorly understood. Although the different species share common pathways; developmental programs, physiological, anatomical, biochemical composition and structural differences must contribute to the operation of unique pathways, genes and proteins. Citrus has a non-climacteric fruit ripening behavior and has a unique anatomical fruit structure. For the last few years a citrus genome-wide ESTs project has been initiated and consists of 222,911 clones corresponding to 19,854 contigs and 37,138 singletons. Taking advantage of the citrus database we analyzed the citrus proteome. Using LC-MS/MS we analyzed soluble and enriched membrane fractions of mature citrus fruit to identify the proteome of fruit juice cells. We have identified ca. 1,400 proteins from these fractions by searching NCBI-nr (green plants) and citrus ESTs databases, classified these proteins according to their putative function and assigned function according to known biosynthetic pathways. PMID:17541628

Katz, E; Fon, M; Lee, Y J; Phinney, B S; Sadka, A; Blumwald, E

2007-09-01

87

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

Microsoft Academic Search

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

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

2010-01-01

88

Susceptibility of highbush blueberry (Vaccinium corymbosum L.) cultivars to Godronia canker (Godronia cassandrae f. sp. vaccinii) in Norway Anfälligkeit von Sorten der Amerikanischen Blaubeeren für Godronia Krebs  

Microsoft Academic Search

Summary Godronia canker, caused by the fungus Godronia cassan- drae f. sp. vaccinii, was detected for the first time on high- bush blueberry (Vaccinium corymbosum) in Norway in 1995, and has caused severe stem wilting and dieback of young bushes. The disease was investigated over five years (1995-1999) in two experimental plantings, and in a sur- vey carried out in

Gunn Mari Strømeng; Arne Stensvand

89

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

PubMed

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

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

2013-01-15

90

University of Florida Citrus Research and Education Center  

NSDL National Science Digital Library

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

91

Genome-Wide Mutagenesis of Xanthomonas axonopodis pv. citri Reveals Novel Genetic Determinants and Regulation Mechanisms of Biofilm Formation  

Microsoft Academic Search

Xanthomonas axonopodis pv. citri (Xac) causes citrus canker disease, a major threat to citrus production worldwide. Accumulating evidence suggests that the formation of biofilms on citrus leaves plays an important role in the epiphytic survival of this pathogen prior to the development of canker disease. However, the process of Xac biofilm formation is poorly understood. Here, we report a genome-scale

Jinyun Li; Nian Wang

2011-01-01

92

Clarification of Citrus Juices.  

National Technical Information Service (NTIS)

A process for the clarification of citrus juices is disclosed. Polygalacturonic acid is added to cloudy citrus juice. The resultant coagulated material is removed from solution leaving a clear liquid.

R. A. Baker J. H. Bruemmer

1977-01-01

93

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

PubMed

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

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

2014-01-01

94

Citrus Grove Mapping  

NASA Technical Reports Server (NTRS)

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.

1980-01-01

95

Occurrence of shallow bark canker of walnut (Juglans regia) in southern provinces of Iran.  

PubMed

From April 2001 to November 2002, samples of walnut branches and trunks with symptoms of shallow bark canker were collected from Fars and Kohgiluyeh-va-Boyerahmad provinces. Symptoms of the disease were small cracks in the bark of the trunk and scaffold branches of mature trees with dark watery exudates which stained the affected trunk or limb. By removal of phelloderm, extensive necrosis of the underlying tissues was observed. In some cases, necrosis extended to cambium and outer xylem. Sixty-one strains of a bacterium were isolated from infected tissues using EMB and YDC media. On the basis of standard biochemical and physiological tests the bacterium was identified as Brenneria nigrifluens. The pathogen was found to be wide-spread in the provinces. Isolates were compared by physiological and biochemical characters, antibiotic sensitivity and protein electrophoretic pattern. Most of the strains were fairly similar in phenotypic features and electrophoretic profiles ofwhole-cell proteins were similar to each other and to reference strain (B. nigrifluens 5D313). Inoculation of 1-2 years-old walnut seedlings in May and June produced blackening symptoms and the bacterium survived for long period in infected tissues. This is the first report of the shallow bark canker of walnut in southern Iran. PMID:19069966

Yousefikopaei, F; Taghavi, S M; Banihashemi, Z

2007-05-01

96

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

PubMed

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

Kim, Kwang Soo; Beresford, Robert M

2012-02-01

97

Delimiting cryptic pathogen species causing apple Valsa canker with multilocus data  

PubMed Central

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

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

2014-01-01

98

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

PubMed

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

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

2014-04-01

99

Citrus and Prunuscopia-like retrotransposons.  

PubMed

Many of the world's most important citrus cultivars ("Washington Navel", satsumas, clementines) have arisen through somatic mutation. This phenomenon occurs fairly often in the various species and varieties of the genus.The presence of copia-like retrotransposons has been investigated in fruit trees, especially citrus, by using a PCR assay designed to detect copia-like reverse transcriptase (RT) sequences. Amplification products from a genotype of each the following species Citrus sinensis, Citrus grandis, Citrus clementina, Prunus armeniaca and Prunus amygdalus, were cloned and some of them sequenced. Southern-blot hybridization using RT clones as probes showed that multiple copies are integrated throughout the citrus genome, while only 1-3 copies are detected in the P. armeniaca genome, which is in accordance with the Citrus and Prunus genome sizes. Sequence analysis of RT clones allowed a search for homologous sequences within three gene banks. The most similar ones correspond to RT domains of copia-like retrotransposons from unrelated plant species. Cluster analysis of these sequences has shown a great heterogeneity among RT domains cloned from the same genotype. This finding supports the hypothesis that horizontal transmission of retrotransposons has occurred in the past. The species presenting a RT sequence most similar to citrus RT clones is Gnetum montanum, a gymnosperm whose distribution area coincides with two of the main centers of origin of Citrus spp. A new C-methylated restriction DNA fragment containing a RT sequence is present in navel sweet oranges, but not in Valencia oranges from which the former originated suggesting, that retrotransposon activity might be, at least in part, involved in the genetic variability among sweet orange cultivars. Given that retrotransposons are quite abundant throughout the citrus genome, their activity should be investigated thoroughly before commercializing any transgenic citrus plant where the transgene(s) is part of a viral genome in order to avoid its possible recombination with an active retroelement. Focusing on other strategies to control virus diseases is recommended in citrus. PMID:22665184

Asíns, M J; Monforte, A J; Mestre, P F; Carbonell, E A

1999-08-01

100

Influence of Soluble and SlowRelease Fertilizers on Vegetative Growth of Containerized Citrus Nursery Trees  

Microsoft Academic Search

The production system for certified citrus nursery trees in São Paulo State, Brazil, stipulates the use of screenhouses, rigorous selection of rootstocks, and the production of budwood under high standards in order to prevent diseases such as sudden death, Citrus Var, and foot rot (Phytophthora spp.). The establishment of adequate nutritional levels for citrus nursery trees also leads to higher

E. A. Girardi; F. A. A. Mourão Filho; C. C. D. Graf; F. B. Olic

2005-01-01

101

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

NSDL National Science Digital Library

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

2013-06-12

102

Autoinflammatory Diseases  

MedlinePLUS

... treatment, a synthetic form of human IL-1Ra. Behçet’s Disease Behçet’s disease causes canker sores or ulcers in the ... of the digestive tract, brain, and spinal cord. Behçet’s disease is common in the Middle East, Asia, ...

103

The stem canker (blackleg) fungus, Leptosphaeria maculans, enters the genomic era.  

PubMed

SUMMARY Leptosphaeria maculans is the most ubiquitous pathogen of Brassica crops, and mainly oilseed brassicas (oilseed rape, canola), causing the devastating 'stem canker' or 'blackleg'. This review summarizes our current knowledge on the pathogen, from taxonomic issues to specific life traits. It mainly illustrates the importance of formal genetics approaches on the pathogen side to dissect the interaction with the host plants. In addition, this review presents the main current research topics on L. maculans and focuses on the L. maculans genome initiative recently begun, including its main research issues. Taxonomy: Leptosphaeria maculans (Desm.) Ces. & de Not. (anamorph Phoma lingam Tode ex Fr.). Kingdom Fungi, Phylum Ascomycota, Class Dothideomycetes (Loculoascomycetes), Order Pleosporales, Genus Leptosphaeria, Species maculans. Host range: cultivated Brassicas such as Brassica napus (oilseed rape, canola), B. rapa, B. juncea, B. oleracea, etc., along with numerous wild crucifers species. Arabidopsis thaliana was recently reported to be a potential host for L. maculans. Primary disease symptoms are greyish-green collapse of cotyledon or leaf tissue, without a visible margin, bearing tiny black spots (pycnidia). The fungus then develops an endophytic symptomless growth for many months. Secondary symptoms, at the end of the growing season, are dry necroses of the crown tissues with occasional blackening (stem canker or blackleg) causing lodging of the plants. Pseudothecia differentiate on leftover residues. Seedling damping-off and premature ripening are also reported under certain environmental conditions. Useful websites: Leptosphaeria maculans sequencing project at Genoscope: http://www.genoscope.cns.fr/externe/English/Projets/Projet_DM/organisme_DM.html; the SECURE site: http://www.secure.rothamsted.ac.uk/ the 'Blackleg' group at the University of Melbourne: http://www.botany.unimelb.edu.au/blackleg/overview.htm. PMID:20565653

Rouxel, T; Balesdent, M H

2005-05-01

104

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

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

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

105

Characterizing the citrus cultivar Carrizo genome through 454 shotgun sequencing.  

PubMed

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

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

2011-12-01

106

USO DE MARCADORES ISOENZIMÁTICOS NA IDENTIFICAÇÃO DE POLIEMBRIÕES DO 'CITRAVO' (Citrus limonia Osb. X Poncirus trifoliata (L.) Raf.)1  

Microsoft Academic Search

With the objective to contribute with the reduction of disease vulnerability of Brazilian orchards, a new citrus rootstock cultivar was obtained at the Federal University of Lavras - UFLA, through controlled crosses between 'Rangpur-lime' (Citrus limonia Osb.), as female parent, and Poncirus trifoliata (L.) Raf., with the offspring named 'Citravo' (Citrus limonia Osb. X Poncirus trifoliata (L.) Raf.). For the

MÍVIA ROSA DE MEDEIROS; RENATA SILVA MANN; MARCELO VICHIATO; MOACIR PASQUAL

107

Production of DAPG and HCN by Pseudomonas sp. LBUM300 contributes to the biological control of bacterial canker of tomato.  

PubMed

Bacterial canker caused by Clavibacter michiganensis subsp. michiganensis is known to cause significant economic losses to tomato production worldwide. Biological control has been proposed as an alternative to current chemical containment methods, which are often inefficient and may leave adverse effects on the environment. However, only little headway has so far been made in developing biocontrol strategies against C. michiganensis subsp. michiganensis. To address this knowledge gap, we investigated the antagonistic capacity of PCA, produced by Pseudomonas sp. LBUM223, and DAPG and HCN, both produced by Pseudomonas sp. LBUM300, on C. michiganensis subsp. michiganensis under in vitro and in planta conditions. Nonsynthesizing isogenic mutants of the producer strains were also developed to further dissect the role of each individual metabolite on C. michiganensis subsp. michiganensis biological control. Novel specific quantitative polymerase chain reaction TaqMan assays allowed quantification of C. michiganensis subsp. michiganensis in tomato plants and rhizospheric soil. Pseudomonas spp. LBUM223 and LBUM300 significantly repressed C. michiganensis subsp. michiganensis growth in vitro, while their respective nonproducing mutants showed less or no significant antagonistic activity. In planta, only Pseudomonas sp. LBUM300 was capable of significantly reducing disease development and C. michiganensis subsp. michiganensis rhizospheric population, suggesting that the production of both DAPG and HCN was involved. In summary, simultaneous DAPG/HCN production by Pseudomonas sp. LBUM300 shows great potential for controlling bacterial canker of tomato. PMID:22713078

Lanteigne, Carine; Gadkar, Vijay J; Wallon, Thérèse; Novinscak, Amy; Filion, Martin

2012-10-01

108

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

PubMed Central

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.

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

2012-01-01

109

Novel hosts of the Eucalyptus canker pathogen Chrysoporthe cubensis and a new Chrysoporthe species from Colombia.  

PubMed

The pathogen Chrysoporthe cubensis (formerly Cryphonectria cubensis) is best known for the important canker disease that it causes on Eucalyptus species. This fungus is also a pathogen of Syzygium aromaticum (clove), which is native to Indonesia, and like Eucalyptus, is a member of Myrtaceae. Furthermore, C. cubensis has been found on Miconia spp. native to South America and residing in Melastomataceae. Recent surveys have yielded C. cubensis isolates from new hosts, characterized in this study based on DNA sequences for the ITS and beta-tubulin gene regions. These hosts include native Clidemia sericea and Rhynchanthera mexicana (Melastomataceae) in Mexico, and non-native Lagerstroemia indica (Pride of India, Lythraceae) in Cuba. Isolates from these hosts and areas group in the sub-clade of C. cubensis accommodating the South American collections of the fungus. This sub-clade also includes isolates recently collected from Eucalyptus in Cuba, which are used to epitypify C. cubensis. New host records from Southeast Asia include exotic Tibouchina urvilleana from Singapore and Thailand and native Melastoma malabathricum (Melastomataceae) in Sumatra, Indonesia. Consistent with their areas of occurrence isolates from the latter collections group in the Asian sub-clade of C. cubensis. DNA sequence comparisons of isolates from Tibouchina lepidota in Colombia revealed that they represent a new sub-clade within the greater Chrysoporthe clade. Isolates in this clade are described as Chrysoporthe inopina sp. nov., based on distinctive morphological differences. PMID:16876702

Gryzenhout, Marieka; Rodas, Carlos A; Portales, Julio Mena; Clegg, Paul; Wingfield, Brenda D; Wingfield, Michael J

2006-07-01

110

In-vitro evaluation of bioactive compounds, anti-oxidant, lipid peroxidation and lipoxygenase inhibitory potential of Citrus karna L. peel extract  

Microsoft Academic Search

Many medicinal plants have been studied for their antioxidant and their pharmacological activity. Citrus species were well documented as potential antioxidant based therapy for cancer, inflammation, heart disease. Citrus seeds and peels have been shown to possess high antioxidant activity. Therefore, the present study to explore the antioxidant\\u000a and lipid peroxidation & lipoxygenase inhibitory action of Citrus karna peel extracts

Jagdeep Singh; Shailja Sood; Arunachalam Muthuraman

111

Molecular analysis of the coat protein and minor coat protein genes of New Zealand Citrus tristeza virus isolates that overcome the resistance of Poncirus trifoliata (L.) Raf  

Microsoft Academic Search

Poncirus trifoliata (L.) Raf. and trifoliate orange hybrid species comprise 90% of the citrus rootstock used in NewZealand. The resistance expressed\\u000a by P. trifoliata to Citrus tristeza virus is in part responsible for the NewZealand citrus industry not suffering severe losses to this disease. However, isolates\\u000a of Citrus tristeza virus have been identified in NewZealand that can overcome this resistance

S. J. Harper; T. E. Dawson; P. A. Mooney; M. N. Pearson

2008-01-01

112

Modeling huanglongbing transmission within a citrus tree  

PubMed Central

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

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

2012-01-01

113

Modeling huanglongbing transmission within a citrus tree.  

PubMed

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

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

2012-07-24

114

Analysis of 13000 unique Citrus clusters associated with fruit quality, production and salinity tolerance  

Microsoft Academic Search

BACKGROUND: Improvement of Citrus, the most economically important fruit crop in the world, is extremely slow and inherently costly because of the long-term nature of tree breeding and an unusual combination of reproductive characteristics. Aside from disease resistance, major commercial traits in Citrus are improved fruit quality, higher yield and tolerance to environmental stresses, especially salinity. RESULTS: A normalized full

Javier Terol; Ana Conesa; Jose M Colmenero; Manuel Cercos; Francisco Tadeo; Javier Agustí; Enriqueta Alós; Fernando Andres; Guillermo Soler; Javier Brumos; Domingo J Iglesias; Stefan Götz; Francisco Legaz; Xavier Argout; Brigitte Courtois; Patrick Ollitrault; Carole Dossat; Patrick Wincker; Raphael Morillon; Manuel Talon

2007-01-01

115

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

National Technical Information Service (NTIS)

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

F. I. McCracken R. Rousseau

1991-01-01

116

Distribution and management of citrus in California: implications for management of glassy-winged sharpshooter.  

PubMed

The epidemiology of Pierce's disease of grape (Vitis spp.) in California has changed over the past 10 yr due to the introduction of an exotic vector, Homalodisca vitripennis (Germar), the glassy-winged sharpshooter. Although this insect is highly polyphagous, citrus (Citrus spp.) is considered a preferred host and proximity to citrus has been implicated as a significant risk factor in recent epidemics of Pierce's disease in southern California. Consequently, a detailed knowledge of the distribution and management of citrus in relation to grape is needed to improve insect and disease management. Analysis of data on the area planted to these two commodities indicates that only five counties in California concomitantly grow >1,000 ha of grape and >1,000 ha of citrus: Riverside, Kern, Tulare, Fresno, and Madera counties. Comparison of the distribution of grape and citrus within each of these counties indicates that the percentage of grape that is in proximity to citrus is greatest for Riverside County, but the total area of grape that is in proximity to citrus is greater for Fresno, Kern, and Tulare counties. The use of carbamates, neonicotinoids, organophosphates, and pyrethroids as part of the citrus pest management program for control of key insect pests was compared among the same five counties plus Ventura County from 1995 to 2006. Ventura County was included in this analysis as this county grows >10,000 ha of citrus and has established glassy-winged sharpshooter populations. The use of these broad-spectrum insecticides was lowest in Riverside and Ventura counties compared with the other four counties. Analysis of historical trapping data at the county scale indicates a negative association of broad-spectrum insecticide use with glassy-winged sharpshooter abundance. These results are used to retrospectively analyze the Pierce's disease outbreaks in Kern and Riverside counties. PMID:18767707

Sisterson, Mark S; Yacoub, Rosie; Montez, Greg; Grafton-Cardwell, Elizabeth E; Groves, Russell L

2008-08-01

117

Grouping and comparison of Indian citrus tristeza virus isolates based on coat protein gene sequences and restriction analysis patterns  

Microsoft Academic Search

Summary.  ?Citrus tristeza virus (CTV) is an aphid-transmitted closterovirus, which causes one of the most important citrus diseases worldwide. Isolates of\\u000a CTV differ widely in their biological properties. CTV-infected samples were collected from four locations in India: Bangalore\\u000a (CTV-B), Delhi (CTV-D), Nagpur (CTV-N), and Pune (CTV-P), and were maintained by grafting into Kagzi lime (Citrus aurantifolia (Christm. Swing.). All isolates produced

A. Roy; P. Ramachandran; R. H. Brlansky

2003-01-01

118

Citrus tristeza virus-host interactions  

PubMed Central

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

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

2013-01-01

119

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

SciTech Connect

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.

Old, K.M.; Gibbs, R.; Craig, I.; Myers, B.J. (CSIRO, Canberra (Australia)); Yuan, Z.Q. (Xinjiang August 1st Agricultural College (China))

1990-01-01

120

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

PubMed

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

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

2014-04-01

121

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

PubMed

ABSTRACT The aggressiveness of strains of Xanthomonas axonopodis pv. citri on seven Citrus species, including Citrus sinensis (navel orange), C. paradisi (grapefruit), C. unshiu (Satsuma mandarin), C. junos (Yuzu), C. aurantifolia ('Mexican' lime), C. tachibana (Tachibana), and C. grandis (pummelo: 'Otachibana', 'Banpeiyu', and 'Anseikan'), were assessed by comparing lesion expansion and growth in planta, using a prick inoculation method. The existence of two groups distinct in aggressiveness was demonstrated on the pummelo cultivars, whereas the remaining species tested were uniformly susceptible. The two groups of strains were distinct in lesion expansion and growth in planta; however, both caused canker lesions on the 'Otachibana' pummelo. The sensitivity of the bacterial strains to phages Cp1 and Cp2 was associated with differences in aggressiveness. Namely, all the strains sensitive to Cp2 but resistant to Cp1 were aggressive to 'Otachibana', whereas all the strains sensitive to Cp1 but resistant to Cp2 were weakly aggressive. When a repetitive sequence-based polymerase chain reaction amplification was carried out by enterobacterial repetitive intergeneric consensus (ERIC) sequences (ERIC1R and ERIC2) as the primers, these two groups were also distinguishable by the presence or absence of a 1.8-kb DNA fragment among otherwise identical fragments. The 1.8-kb fragment was amplified only from the strains aggressive to C. grandis. PMID:18943380

Shiotani, H; Ozaki, K; Tsuyumu, S

2000-12-01

122

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

PubMed Central

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

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

2012-01-01

123

Germacrenes in Citrus Peel Oils  

Microsoft Academic Search

The germacrene composition of various citrus peel oils was investigated. Detection and quantification of the thermally sensitive germacrenes A and C was achieved by employing extremely gentle GC conditions with 100°C maximum in injector and GC-oven. Germacrene A was found in all analyzed citrus oils with values from trace level to 0.46% of the volatiles, depending on variety and provenance.

Wolfgang Feger; Herbert Brandauer; Herta Ziegler

2001-01-01

124

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

PubMed Central

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

2014-01-01

125

Analysis of full-length sequences of two Citrus yellow mosaic badnavirus isolates infecting Citrus jambhiri (Rough Lemon) and Citrus sinensis L. Osbeck (Sweet Orange) from a nursery in India.  

PubMed

Citrus yellow mosaic badna virus (CMBV), a member of the Family Caulimoviridae, Genus Badnavirus is the causative agent of mosaic disease among Citrus species in southern India. Despite its reported prevalence in several citrus species, complete information on clear functional genomics or functional information of full-length genomes from all the CMBV isolates infecting citrus species are not available in publicly accessible databases. CMBV isolates from Rough Lemon and Sweet Orange collected from a nursery were cloned and sequenced. The analysis revealed high sequence homology of the two CMBV isolates with previously reported CMBV sequences implying that they represent new variants. Based on computational analysis of the predicted secondary structures, the possible functions of some CMBV proteins have been analyzed. PMID:22926812

Anthony Johnson, A M; Borah, B K; Sai Gopal, D V R; Dasgupta, I

2012-12-01

126

In Vitro Regeneration and Somatic Embryogenesis in (Citrus aurantifolia and Citrus sinensis)  

Microsoft Academic Search

Most of the plant regeneration processes in citrus, through tissue culture, involve somatic embryogenesis. The optimization of these processes is important for the development of in vitro plant improvement. Nodal segments and leaf discs of sweet orange (Citrus sinensis L.) cv. Musambi and Lime (Citrus aurantifolia ) cv. Kaghzi Nimbu were used to obtain aseptically raised plantlets of Lime (Citrus

RASHAD MUKHTAR; M. MUMTAZ KHAN; RAMZAN RAFIQ; ADNAN SHAHID; FAROOQ AHMAD KHAN

127

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

PubMed Central

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

2010-01-01

128

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

PubMed

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

da Silva Guimarães, Lúcio Mauro; de Resende, Marcos Deon Vilela; Lau, Douglas; Rosse, Leonardo Novaes; Alves, Alexandre Alonso; Alfenas, Acelino Couto

2010-07-01

129

[Chemical composition and bioactive compounds of flour of orange (Citrus sinensis), tangerine (Citrus reticulata) and grapefruit (Citrus paradisi) peels cultivated in Venezuela].  

PubMed

The purpose of this research was to evaluate the chemical composition and some bioactive compounds in the peel's flour of some of the most consumed citrus fruits cultivated in Venezuela. Chemical composition as well as some trace elements, ascorbic acid, carotenoids dietary fiber, total polyphenols and their antiradical efficiency, using the 2,2-diphenyl-1-picrylhidracyl (DPPH) were assessed in the dried peels of orange (Citrus sinensis), tangerine (Citrus reticulata) and white grapefruit (Citrus paradisi). Moisture, fat, protein and ash content for all samples showed statistical differences (p < 0.05). Tangerine's peel showed the highest magnesium and carotenoid content, while highest ascorbic acid and carotenoid content was found in the grapefruit's peel. Dietary fiber content presented significant high value in the tangerine peel. All samples presented high content of extractable polyphenols (4.33; 7.6 and 5.1 g/100g). The highest antiradical efficiency was shown by the tangerine's peel, value which correlates with the polyphenol content. These results suggest that tangerine peel should be the most suitable, to reduce risk of some diseases such as cardiovascular and some associated to lipid oxidation. Studied samples are good sources of dietary fiber and phenolic compounds, whose use could be useful in the formulation of functional foods, taking advantage of the presence of dietary fiber and antioxidant compounds in only one ingredient. PMID:16454058

Rincón, Alicia M; Vásquez, A Marina; Padilla, Fanny C

2005-09-01

130

Biosynthesis of Citric Acid in Citrus Fruits  

Microsoft Academic Search

NO detailed study has so far been made to find out the mechanism of the formation and accumulation of citric acid in citrus fruits even though studies on the change of acidity and pH during ripening have been reported1. Investigations are in progress in this laboratory to study the biosynthesis of citric acid in citrus fruit (Citrus acida), as a

T. N. Sekhara Varma; C. V. Ramakrishnan

1956-01-01

131

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

PubMed Central

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

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

2012-01-01

132

Florida Citrus Industry Oral Histories  

NSDL National Science Digital Library

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

133

Pseudomonas syringae pv. actinidiae from Recent Outbreaks of Kiwifruit Bacterial Canker Belong to Different Clones That Originated in China  

PubMed Central

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

Butler, Margi I.; Stockwell, Peter A.; Black, Michael A.; Day, Robert C.; Lamont, Iain L.; Poulter, Russell T. M.

2013-01-01

134

A comparison of nitrogen use efficiency definitions in Citrus rootstocks  

Microsoft Academic Search

Nitrogen use efficiency (NUE) definitions, commonly used in literature, are evaluated in response to nitrate availability in four citrus rootstocks, Rough Lemon (Citrus jambhiri Lush) (RL), Sweet Orange (Citrus sinensis (L.) Osbeck) (SwO), Cleopatra Mandarin (Citrus reshni Hort ex Tan.) (CM) and Sour Orange (Citrus aurantium L.) (SO). The application of diverse definitions determine different characterizations in N-efficiency among rootstocks.

Agostino Sorgonà; Maria Rosa Abenavoli; Pietro Giorgio Gringeri; Giovanni Cacco

2006-01-01

135

Evaluation of citrus fibers as a tablet excipient.  

PubMed

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

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

2014-04-01

136

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

Federal Register 2010, 2011, 2012, 2013

...Citrus greening is a bacterial disease, caused by strains of the bacterial pathogen ``Candidatus...appropriate, of automated, electronic, mechanical, and other...e.g., permitting electronic submission of...

2011-12-16

137

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

138

Chipping citrus wood for gasification  

SciTech Connect

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.

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

1985-01-01

139

Um Ambiente para Monitoramento da Morte Súbita dos Citrus  

Microsoft Academic Search

This article describes the implementation and applications of computational-statistical surveillance system for the Citrus Sudden Death Disease. The data is stored in a spatio-temporal TerraLib database and statistical analysis are performed using functions written as a add-on pack- age for the R language called Rcitrus which implements some specialized statistical methods and also interfaces with other packages such as geoR,

Elias Teixeira Krainski; Paulo Justiniano Ribeiro Jr.; Pedro Ribeiro De Andrade Neto; Renato Beozzo Bassanezi

2005-01-01

140

Antifungal activity of Moroccan plants against citrus fruit pathogens  

Microsoft Academic Search

The aim of this study was to find an alternative to the chemical fungicides currently used in the control of postharvest citrus\\u000a fruit diseases. Here we screened twenty-one medicinal and aromatic plants used in southern Moroccan traditional medicine for\\u000a their activity against Penicillium digitatum, Penicillium italicum and Geotrichum candidum. The antifungal efficacy of powders, essential oils and solvent extracts of

N. Ameziane; H. Boubaker; H. Boudyach; F. Msanda; A. Jilal; A. Ait Benaoumar

2007-01-01

141

A multiplex polymerase chain reaction method for reliable, sensitive and simultaneous detection of multiple viruses in citrus trees  

Microsoft Academic Search

A multiplex polymerase chain reaction (mPCR) assay was developed to detect six RNA and one DNA citrus virus: Citrus leaf rugose virus (CLRV), Citrus psorosis virus (CPsV), Citrus tatter leaf virus (CTLV), Citrus tristeza virus (CTV), Citrus variegation virus (CVV), Citrus yellow mosaic virus (CYMV), and Indian citrus ringspot virus (ICRSV) from citrus plants. These seven viruses are classified in

Avijit Roy; Amer Fayad; G. Barthe; R. H. Brlansky

2005-01-01

142

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

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

143

Inheritance and heritability of resistance to citrus leprosis.  

PubMed

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

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

144

Nitrogen availability to citrus seedlings from urea and from mineralization of citrus leaf or compost  

Microsoft Academic Search

A pot experiment was conducted using a Candler fine sand (hyperthermic, uncoated, Typic Quartzipsamments) amended with either citrus leaves or compost, to measure the nitrogen (N) mineralization and its availability to two citrus rootstock seedlings. A rapid increase in NH4?N concentration was evident in the soil amended with citrus leaves as compared to compost during the initial 14 to 20

H. Dou; A. K. Alva

1998-01-01

145

IMPROVEMENT IN YIELD AND QUALITY OF KINNOW (CITRUS DELICIOSA X CITRUS NOBILIS) BY POTASSIUM FERTILIZATION  

Microsoft Academic Search

Citrus, especially Kinnow, fruit yield and quality in Pakistan is not competitive with other countries, which could be mainly attributed to a lack of good nutrient management for citrus orchards. Many of the soils under these orchards have been reported as deficient in potassium (K). Therefore, work was initiated for improving citrus fruit yield, size, and quality through K nutrition

M. Yasin Ashraf; Attiya Gul; F. Hussain; G. Ebert

2010-01-01

146

Selection of Antagonistic Bacteria of Clavibacter michiganensis subsp. michiganensis and Evaluation of Their Efficiency Against Bacterial Canker of Tomato  

Microsoft Academic Search

A 178 bacterial strains, antagonistic towards Clavibacter michiganensis subsp. michiganensis , the causal agent of bacterial canker of tomato, were isolated from bulk soil, the rhizosphere and rhizoplane of tomato, originating from different sites in the Souss-Massa Valley, Agadir, Morocco. The strains were characterized on the basis of the Gram stain, sporulation, fluorescence on King's B medium and physiological tests.

E. H. Boudyach; M. Fatmi; O. Akhayat; E. Benizri; A. Ait Ben Aoumar

2001-01-01

147

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

PubMed

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

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

2010-01-27

148

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

PubMed

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

Qureshi, Jawwad A; Stansly, Philip A

2011-12-01

149

Citrus Allergy from Pollen to Clinical Symptoms  

PubMed Central

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

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

2013-01-01

150

Plasmid-DNA Based Probes and Procedure for Rapid and Specific Detection of Xanthomonas Campestris pv. Citri.  

National Technical Information Service (NTIS)

Citrus bacterial canker disease (CBCD) is a serious disease of citrus, and the causal pathogen, Xanthomonas campestris pv. citri (X.c. citri) is the subject of international quarantine. Although eradicated from the United States at great cost in the first...

J. S. Hartung O. P. Pruvost

1992-01-01

151

Pharmacological properties of citrus and their ancient and medieval uses in the Mediterranean region  

Microsoft Academic Search

This paper reviews the pharmacological properties of Mediterranean-grown citrus species (Citrus L., Rutaceae), including citron (Citrus medica L.), lime (Citrus ×auantiifolia [Christm.] Swingle), lemon (Citrus ×limon [L.] Osbeck), bitter orange (Citrus ×aurantium L.) and pomelo (Citrus maxima [Burm.] Merr.), as referred to in ancient, medieval and 16th century sources. The virtues of the species reported in these texts were compared

Beatriz Álvarez Arias; Luis Ramón-Laca

2005-01-01

152

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

PubMed

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

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

2013-01-01

153

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

PubMed Central

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

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

2013-01-01

154

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

NASA Astrophysics Data System (ADS)

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

Sujitha, Mohanan V.; Kannan, Soundarapandian

2013-02-01

155

Distribution of citrus viroids and Apple stem grooving virus on citrus trees in Japan using multiplex reverse transcription polymerase chain reaction  

Microsoft Academic Search

The distribution of citrus viroids – Citrus exocortis viroid (CEVd), Citrus bent leaf viroid (CBLVd), Citrus viroid (CVd)-I-LSS, Hop stunt viroid (HSVd), Citrus viroid III (CVd-III), Citrus viroid IV (CVd-IV), and Citrus viroid OS (CVd-OS) – and Apple stem grooving virus (ASGV; synonym: Citrus tatter leaf virus) were investigated using the multiplex reverse transcription polymerase chain reaction\\u000a on samples from

Takao Ito; Nobuyuki Namba; Tsutae Ito

2003-01-01

156

Simultaneous detection of six citrus viroids and Apple stem grooving virus from citrus plants by multiplex reverse transcription polymerase chain reaction  

Microsoft Academic Search

We developed a multiplex reverse transcription polymerase chain reaction (RT-PCR) to detect six citrus viroids: Citrus exocortis viroid (CEVd), Citrus bent leaf viroid (CBLVd), Hop stunt viroid (HSVd), Citrus viroid III (CVd-III), Citrus viroid IV (CVd-IV) and Citrus viroid OS (CVd-OS) and Apple stem grooving virus (ASGV, synonym: Citrus tatter leaf virus (CTLV)) from citrus plants. The multiplex RT-PCR was

Takao Ito; Hiroyuki Ieki; Katsumi Ozaki

2002-01-01

157

[Climatic suitability of citrus in subtropical China].  

PubMed

By applying the theories of ecological suitability and the methods of fuzzy mathematics, this paper established a climatic suitability model for citrus, calculated and evaluated the climatic suitability and its spatiotemporal differences for citrus production in subtropical China, and analyzed the climatic suitability of citrus at its different growth stages and the mean climatic suitability of citrus in different regions of subtropical China. The results showed that the citrus in subtropical China had a lower climatic suitability and a higher risk at its flower bud differentiation stage, budding stage, and fruit maturity stage, but a higher climatic suitability and a lower risk at other growth stages. Cold damage and summer drought were the key issues affecting the citrus production in subtropical China. The citrus temperature suitability represented a latitudinal zonal pattern, i. e., decreased with increasing latitude; its precipitation suitability was high in the line of "Sheyang-Napo", medium in the southeast of the line, low in the northwest of the line, and non in high mountainous area; while the sunlight suitability was in line with the actual duration of sunshine, namely, higher in high-latitude areas than in low-latitude areas, and higher in high-altitude areas than in plain areas. Limited by temperature factor, the climatic suitability was in accordance with temperature suitability, i. e., south parts had a higher suitability than north parts, basically representing latitudinal zonal pattern. From the analysis of the inter-annual changes of citrus climatic suitability, it could be seen that the citrus climatic suitability in subtropical China was decreasing, and had obvious regional differences, suggesting that climate change could bring about the changes in the regions suitable for citrus production and in the key stages of citrus growth. PMID:21043095

Duan, Hai-Lai; Qian, Huai-Sui; Li, Ming-Xia; Du, Yao-Dong

2010-08-01

158

High codon adaptation in citrus tristeza virus to its citrus host  

PubMed Central

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

2012-01-01

159

Variation in rates of spore deposition of Fusarium circinatum, the causal agent of pine pitch canker, over a 12-month-period at two locations in Northern California.  

PubMed

Patterns of spore deposition by Fusarium circinatum, the causal agent of pine pitch canker (PPC) of Monterey pine (Pinus radiata) and other conifers, were studied between May 2003 and April 2004 at two sites in Northern California using a novel spore trapping method combined with a real-time polymerase chain reaction (PCR) approach. At each study site, two plots were sampled by placing spore traps at 100 m intervals along transects 600 m in length. The air was sampled continuously by exchanging the spore traps every 2 weeks. The spore deposition rate (DR), ranged from 0 to 1.3 x 10(5) spores m(2). Spores were detected throughout the year, with higher trapping frequencies (TF) during the rainy season (November to April), than during the dry season (May to October). The detection of spores on traps at distances larger than 200 m from any Monterey pine, suggests at least midrange aerial dispersal. Finally, different inoculum loads were associated with trees displaying different levels of disease symptoms, suggesting infectiousness of the pathogen varies as the disease progresses. This study represents one of the first documenting continuous inoculum pressure values over an entire year for a forest pathogen, and provides important epidemiological information that will be invaluable in the development of disease progression models. PMID:18943249

Garbelotto, M; Smith, T; Schweigkofler, W

2008-01-01

160

Adventitious Citrus Juice Vesicles from Pre-Existing Juice Vesicles.  

National Technical Information Service (NTIS)

The invention comprises adventitious citrus juice vesicles having the unique characteristic that they branch out of pre-existing citrus juice vesicles. This is in contrast to tree-produced citrus juice vesicles which arise from the endocarp of the citrus ...

B. Tisserat

1989-01-01

161

7 CFR 319.56-38 - Citrus from Chile.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Citrus from Chile. 319.56-38 Section 319.56-38...Vegetables § 319.56-38 Citrus from Chile. Clementines (Citrus reticulata ...be imported into the United States from Chile, and grapefruit (Citrus paradisi...

2010-01-01

162

Nitrogen best management practice for citrus trees  

Microsoft Academic Search

Soils in central Florida citrus production region are very sandy, hence are vulnerable to leaching of soluble nutrients and chemicals. The objective of this study was to develop nitrogen (N) and irrigation best management practices for citrus in sandy soils to maintain optimal crop yield and quality, and to minimize N leaching below the rootzone. A replicated plot experiment was

A. K. Alva; S. Paramasivam; A. Fares; T. A. Obreza; A. W. Schumann

2006-01-01

163

Efficiency of different application methods of biocontrol agents and biocides in control of Fusarium root rot on some citrus rootstocks  

Microsoft Academic Search

The efficiency of two biocontrol agents (Trichoderma harzianum NB and Bacillus subtilis NB) and two commercial biocides (Plant Guard and Rhizo-N) in controlling Fusarium root rot disease on some citrus rootstocks was evaluated under artificially infested soil in green house.Fusrium root rot on citrus rootstocks seedlings i.e. sour orange (SO), volkamer lime (VL), rangpur lime (RP) and cleopatra mandarin (CL)

Riad Sedki Riad El-Mohamedy

2009-01-01

164

Phytochemical analysis and radical scavenging profile of juices of Citrus sinensis, Citrus anrantifolia, and Citrus limonum  

PubMed Central

Background The aim of the current investigation was to identify bioactive secondary metabolites including phenols, tannins, flavonoids, terpinedes, and steroids and compare the phytochemical analysis and antioxidant profile of the juice extracted from the fruits of Citrus sinensis, Citrus anrantifolia, and Citrus limonum. Results Phytochemical screening is important for the isolation of new, novel, and rare secondary metabolites before bulk extraction. Phytochemical analysis of the desired plant fruits of family Rutaceae revealed the presence of phenols, flavonoids, reducing sugars, steroids, terpinedes and tannins. The fruits of C. sinensis and C. anrantifolia exhibited the presence of phenols, flavonoids, reducing sugars, steroids, terpinedes and tannins, while the fruits of C. limonum indicated the presence of phenols, flavonoids, reducing sugars, terpinedes, and tannins. The fruits of selected plants were also subjected to antioxidant potential by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay against ascorbic acid at various concentrations. Among the tested plants, C. sinensis showed promising antiradical effect (84.81%) which was followed by C. Anrantifolia (80.05%) at 100 ?g/ml against ascorbic acid (96.36%). The C. limonum showed low antioxidant activity among the three selected plants of family Rutaceae. Conclusions The current finding is baseline information in the use of the fruits of selected plants as food supplement which may be due to the presence of antioxidant molecules in the family Rutaceae. Further research is needed in this area to isolate the phenolic constituents which possess ideal antiradical potential.

2014-01-01

165

Canker Sores  

MedlinePLUS

... SLS is a foaming agent found in most toothpastes and mouthwashes. Finally, not getting the right nutrition, ... you brush your teeth . Brush and rinse with toothpastes and mouthwashes that don't contain sodium lauryl ...

166

Canker Sores  

MedlinePLUS

... logged in Home About Us Mission and Vision Leadership Executive Committee Board of Trustees Governance Staff/Contact ... Study Resources Application Process ABOM ABOM Overview ABOM Leadership Fellowship in Dental Surgery ABOM Diplomates Education & Training ...

167

Evaluation of four phloem-specific promoters in vegetative tissues of transgenic citrus plants.  

PubMed

'Mexican' lime (Citrus aurantifolia Swingle) was transformed with constructs that contained chimeric promoter-gus gene fusions of phloem-specific rolC promoter of Agrobacterium rhizogenes, Arabidopsis thaliana sucrose-H(+) symporter (AtSUC2) gene promoter of Arabidopsis thaliana, rice tungro bacilliform virus (RTBV) promoter and sucrose synthase l (RSs1) gene promoter of Oryza sativa (rice). Histochemical ?-glucuronidase (GUS) analysis revealed vascular-specific expression of the GUS protein in citrus. The RTBV promoter was the most efficient promoter in this study while the RSs1 promoter could drive low levels of gus gene expression in citrus. These results were further validated by reverse transcription real-time polymerase chain reaction and northern blotting. Southern blot analysis confirmed stable transgene integration, which ranged from a single insertion to four copies per genome. The use of phloem-specific promoters in citrus will allow targeted transgene expression of antibacterial constructs designed to battle huanglongbing disease (HLB or citrus greening disease), associated with a phloem-limited Gram-negative bacterium. PMID:22228816

Dutt, M; Ananthakrishnan, G; Jaromin, M K; Brlansky, R H; Grosser, J W

2012-01-01

168

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

PubMed Central

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

Tofoli de Araujo, Fabiano; Bolanos-Garcia, Victor M.; Pereira, Cristiane T.; Sanches, Mario; Oshiro, Elisa E.; Ferreira, Rita C. C.; Chigardze, Dimitri Y.; Barbosa, Joao Alexandre Goncalves; de Souza Ferreira, Luis Carlos; Benedetti, Celso E.; Blundell, Tom L.; Balan, Andrea

2013-01-01

169

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

PubMed

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

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

1991-10-01

170

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

Microsoft Academic Search

The Alternaria stem canker resistance locus (Asc-locus), involved in resistance to the fungal pathogen Alternaria alternata f. sp. lycopersici and in insensitivity to host-specific toxins (AAL-toxins) produced by the pathogen, was genetically mapped on the tomato genome. Susceptibility and resistance were assayed by testing a segregating F2 population for sensitivity to AAL-toxins in leaf bioassays. Linkage was observed to phenotypic

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

1989-01-01

171

Inheritance of several sources of resistance to Phomopsis stem canker ( Diaporthe helianthi Munt.-Cvet.) in sunflower ( Helianthus annuus L.)  

Microsoft Academic Search

The hybrids from 2 factorial crosses involving a total of 7 female lines and 11 restorers, representing the known range of\\u000a reaction of sunflower to Phomopsis stem canker and most of the resistance sources used in breeding programmes, were studied\\u000a in multilocational semi-natural attack trials and by artificial infections on leaves and stems in 1996, 1997 and 1998. The\\u000a results

A. Viguié; D. Touvieille de Labrouhe; F. Vear

2000-01-01

172

Essential oil profiles of new Citrus hybrids, a tool for genetic citrus improvement  

Microsoft Academic Search

The essential oil composition of new Citrus hybrids obtained from the Citrus genetic improvement programs at the CRA-Centro di Ricerche per l’Agrumicoltura e le Colture Mediterranee of Acireale, Italy (CRA-ACM), were used to evaluate the fruit quality and to identify new valuable flavor components. The common objective of genetic improvement programs is to generate Citrus cultivars with a higher resistance

Simona Fabroni; Giuseppe Ruberto; Paolo Rapisarda

2012-01-01

173

Radiation preservation of foods of plant origin. Part IV. Subtropical fruits: citrus, grapes, and avocados  

SciTech Connect

Current information on the use of ionizing radiation for improving the storage of subtropical fruits like citrus, grapes, and avocados is reviewed. The feasibility of applying radiation either alone or in combination with other physical or chemical treatments for the control of postharvest fungal diseases is considered. Irradiation effects on the physiology of the fruits as related to respiration, ethylene evolution, changes in major chemical constituents, and quality are discussed. The recent trends in the possible use of irradiation as an alternative treatment to chemical fumigants for disinfestation of citrus and avocados and the prospects for the future application of irradiation for preservation of some of these fruits are outlined. 128 references.

Thomas, P.

1986-01-01

174

Comparison of antifungal activities of Vietnamese citrus essential oils.  

PubMed

Citrus essential oils (EOs) are volatile compounds from citrus peels and widely used in perfumes, cosmetics, soaps and aromatherapy. In this study, inhibition of citrus EOs extracted from Vietnamese orange (Citrus sinensis), mandarin (Citrus reticulata Blanco), pomelo (Citrus grandis Osbeck) and lime (Citrus aurantifolia Swingle) on the growth of plant pathogenic fungi, Mucor hiemalis, Penicillium expansum and Fusarium proliferatum was investigated. The EOs of the citrus peels were obtained by cold-pressing method and the antifungal activity of EOs was evaluated using the agar dilution method. The results show that the EOs had significant antifungal activity. Lime EO was the best inhibitor of M. hiemalis and F. proliferatum while pomelo EO was the most effective against P. expansum. These results indicate that citrus EOs can be used as antifungal natural products in the food, pharmaceutical and cosmetic industries. PMID:22799453

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

2013-03-01

175

Response of Young Citrus Trees on Selected Rootstocks to Nitrogen, Phosphorus, and Potassium Fertilization  

Microsoft Academic Search

The majority of the citriculture in Brazil is located in the state of São Paulo, with a total production area of 700,000 ha. Trees are grafted mostly on ‘Rangpur’ lime (RL; Citrus limonia Osbeck) rootstock. Despite its good horticultural performance, use of other rootstocks has increased with the search for disease-tolerant varieties to improve grove productivity and longevity. Furthermore, there

D. Mattos Jr; J. A. Quaggio; H. Cantarella; A. K. Alva; D. A. Graetz

2006-01-01

176

Determination of the Presence of Huanglongbing in Seeds and Movement of the Pathogen in Citrus reticulata  

Microsoft Academic Search

Problem statement: Huanglongbing (HLB) also known as citrus greening disease is a fastidious phloem-inhabiting bacterium in the genus Candidatus Liberibacter. Using universal primers, the 16S ribosomal DNA sequence of three strains of the bacterium were obtained by PCR. However there is very little information on seed transmissi on and HLB pathogen movement to find a way for control or reduce

Hajivand Shokrollah; Thohirah Lee Abdullah

2009-01-01

177

Aphid biology: Expressed genes from alate Toxoptera citricida, the brown citrus aphid  

Microsoft Academic Search

The brown citrus aphid, Toxoptera citricida (Kirkaldy), is considered the primary vector of citrus tristeza virus, a severe pathogen which causes losses to citrus industries worldwide. The alate (winged) form of this aphid can readily fly long distances with the wind, thus spreading citrus tristeza virus in citrus growing regions. To better understand the biology of the brown citrus aphid

W. B. Hunter; P. M. Dang; M. G. Bausher; J. X. Chaparro; W. McKendree; R. G. Shatters; C. L. McKenzie; X. H. Sinisterra

2003-01-01

178

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

Code of Federal Regulations, 2010 CFR

...States except commercial citrus-producing areas if all...plants are not grown from seed, then the cuttings...from properties where citrus canker is present. ...citrus canker. (6) If citrus canker is found in...may receive new kumquat seed or cuttings from a...

2010-01-01

179

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

Code of Federal Regulations, 2010 CFR

...States except commercial citrus-producing areas if all...plants are not grown from seed, then the cuttings...from properties where citrus canker is present. ...citrus canker. (6) If citrus canker is found in...calamondin and kumquat seed or cuttings from a...

2009-01-01

180

Aphthous stomatitis (canker sores): a consequence of high oral submucosal viscosity (the role of extracellular matrix and the possible role of lectins).  

PubMed

Recurrent aphthous stomatitis (RAS) or canker sores occur in 20-60% of all persons. The lesion occurs because of increased viscosity of oral submucosal extracellular matrix (ECM). The lesions begin in the second decade and peak in the third decade. Sex hormones are an important influence on fibroblasts, especially in the early phase of exposure. Sex hormones are known to concentrate, to a degree, in the bucal mucosa in animals. Lesions of RAS localize clinically and experimentally at sites of trauma. In the skin, edema is known to trigger early cellular inflammation. Increased viscosity of ECM heightens the response. The histopathology of the ulcerated lesions is similar to that which occurs under sites of acute inflammation in the skin. Systemic corticosteroids completely supress the lesions. Caustics, such as silver nitrate and phenol, stop the growth and pain of lesions. Irritants are known to break ECM viscosity. The oral mucosa exerts some control on underlying ECM. Substances such as lectins influencing the mucosa could influence ECM. Soluble substances in food or organisms could also penetrate to influence ECM. A number of different foods have been incriminated as trigger agents in individual cases. This includes gluten in patients with gluten sensitive enteropathy. Gluten is known to alter the mucosa of the small intestine in persons with celiac disease. PMID:1809853

Stone, O J

1991-12-01

181

Analysis of 13000 unique Citrus clusters associated with fruit quality, production and salinity tolerance  

PubMed Central

Background Improvement of Citrus, the most economically important fruit crop in the world, is extremely slow and inherently costly because of the long-term nature of tree breeding and an unusual combination of reproductive characteristics. Aside from disease resistance, major commercial traits in Citrus are improved fruit quality, higher yield and tolerance to environmental stresses, especially salinity. Results A normalized full length and 9 standard cDNA libraries were generated, representing particular treatments and tissues from selected varieties (Citrus clementina and C. sinensis) and rootstocks (C. reshni, and C. sinenis × Poncirus trifoliata) differing in fruit quality, resistance to abscission, and tolerance to salinity. The goal of this work was to provide a large expressed sequence tag (EST) collection enriched with transcripts related to these well appreciated agronomical traits. Towards this end, more than 54000 ESTs derived from these libraries were analyzed and annotated. Assembly of 52626 useful sequences generated 15664 putative transcription units distributed in 7120 contigs, and 8544 singletons. BLAST annotation produced significant hits for more than 80% of the hypothetical transcription units and suggested that 647 of these might be Citrus specific unigenes. The unigene set, composed of ~13000 putative different transcripts, including more than 5000 novel Citrus genes, was assigned with putative functions based on similarity, GO annotations and protein domains Conclusion Comparative genomics with Arabidopsis revealed the presence of putative conserved orthologs and single copy genes in Citrus and also the occurrence of both gene duplication events and increased number of genes for specific pathways. In addition, phylogenetic analysis performed on the ammonium transporter family and glycosyl transferase family 20 suggested the existence of Citrus paralogs. Analysis of the Citrus gene space showed that the most important metabolic pathways known to affect fruit quality were represented in the unigene set. Overall, the similarity analyses indicated that the sequences of the genes belonging to these varieties and rootstocks were essentially identical, suggesting that the differential behaviour of these species cannot be attributed to major sequence divergences. This Citrus EST assembly contributes both crucial information to discover genes of agronomical interest and tools for genetic and genomic analyses, such as the development of new markers and microarrays.

Terol, Javier; Conesa, Ana; Colmenero, Jose M; Cercos, Manuel; Tadeo, Francisco; Agusti, Javier; Alos, Enriqueta; Andres, Fernando; Soler, Guillermo; Brumos, Javier; Iglesias, Domingo J; Gotz, Stefan; Legaz, Francisco; Argout, Xavier; Courtois, Brigitte; Ollitrault, Patrick; Dossat, Carole; Wincker, Patrick; Morillon, Raphael; Talon, Manuel

2007-01-01

182

Enhancement of ?-Carotene Synthesis by Citrus Products  

PubMed Central

?-Ionone, a stimulatory compound in the microbiological production of ?-carotene by mated cultures of Blakeslea trispora, could be replaced with low-cost agricultural by-products (citrus oils, citrus pulp, or citrus molasses) with as good or better carotene yields. Peak yields (81 to 129 mg of carotene per g of dry solids) were achieved in 5 days. The various citrus products tested did not change the pigments produced; all trans-?-carotene remained the pre-dominant pigment. The acid-hydrolyzed soybean meal and corn used in previous production media could be replaced with unhydrolyzed cottonseed embryo meal and corn in a medium that also contained a natural lipid, deodorized kerosene, nonionic detergent, and a precursor.

Ciegler, Alex; Nelson, George E. N.; Hall, Harlow H.

1963-01-01

183

Indexing of Citrus Viroids by Imprint Hybridisation  

Microsoft Academic Search

A method based on the hybridisation of tissue imprints was developed for routine indexing of citrus viroids. For maximum sensitivity and reliability, the inoculation of Citrus medica (Etrog citron) as a viroid amplification host is required. Hybridisation against Digoxigenin-labelled RNA- or DNA-probes followed by detection of viroid-probe hybrids using anti-DIG-alkaline phosphate conjugate and the chemiluminescence substrate CSPD was suitable for

A. Palacio-Bielsa; X. Foissac; N. Duran-Vila

1999-01-01

184

Spontaneous tetraploidy in apomictic seedlings of Citrus  

Microsoft Academic Search

Populations of apomictic seedlings of clones ofCitrus species,Citrus hybrids, andPoncirus in the sub-family Aurantioideae were examined for spontaneous tetraploids as a source of materials for use in breeding experiments.\\u000a Diagnostic features found useful in identifying nucellar tetraploids were leaf shape, petiole blade shape, leaf blade thickness,\\u000a leaf color, comparative size differences in leaf venation, oil glands, and stomata, stem thickness,

H. C. Barrett; D. J. Hutchison

1978-01-01

185

GC-MS metabolomic differentiation of selected citrus varieties with different sensitivity to citrus huanglongbing.  

PubMed

Huanglongbing (HLB) is the most destructive disease of citrus worldwide. The rapid identification of tolerant varieties is considered a critical step towards controlling HLB. GC-MS metabolite profiles were used to differentiate HLB-tolerant citrus varieties 'Poncirus trifoliata' (TR) and 'Carrizo citrange' (CAR) from HLB-sensitive varieties 'Madam Vinous sweet orange' (MV) and 'Duncan' grapefruit (DG). PCR analyses revealed that MV was the most sensitive variety followed by DG and the tolerant varieties CAR and TR. Metabolomic multivariate analysis allowed classification of the cultivars in apparent agreement with PCR results. Higher levels of the amino acids l-proline, l-serine, and l-aspartic acid, as well as the organic acids butanedioic and tetradecanoic acid, and accumulation of galactose in healthy plants were characteristic of the most sensitive variety MV when compared to all other varieties. Only galactose was significantly higher in DG when compared to the tolerant varieties TR and CAR. The tolerant varieties showed higher levels of l-glycine and mannose when compared to sensitive varieties MV and DG. Profiling of the sensitive varieties MV and DG over a 20-week period after inoculation of those with the HLB-containing material revealed strong responses of metabolites to HLB infection that differed from the response of the tolerant varieties. Significant changes of l-threonine level in the leaves from old mature flushes and l-serine, l-threonine, scyllo-inositol, hexadecanoic acid, and mannose in the leaves from young developing flushes were observed in MV. Significant changes in myo-inositol in old flushes and l-proline, indole, and xylose in new flushes were observed in DG. PMID:22326359

Cevallos-Cevallos, Juan M; Futch, David B; Shilts, Turksen; Folimonova, Svetlana Y; Reyes-De-Corcuera, José I

2012-04-01

186

Biology and management of Asian citrus psyllid, vector of the huanglongbing pathogens.  

PubMed

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the most important pest of citrus worldwide because it serves as a vector of "Candidatus Liberibacter" species (Alphaproteobacteria) that cause huanglongbing (citrus greening disease). All commercially cultivated citrus is susceptible and varieties tolerant to disease expression are not yet available. Onset of disease occurs following a long latent period after inoculation, and thus the pathogen can spread widely prior to detection. Detection of the pathogen in Brazil in 2004 and Florida in 2005 catalyzed a significant increase in research on D. citri biology. Chemical control is the primary management strategy currently employed, but recently documented decreases in susceptibility of D. citri to several insecticides illustrate the need for more sustainable tools. Herein, we discuss recent advances in the understanding of D. citri biology and behavior, pathogen transmission biology, biological control, and chemical control with respect to "Candidatus Liberibacter asiaticus." Our goal is to point toward integrated and biologically relevant management of this pathosystem. PMID:23317046

Grafton-Cardwell, Elizabeth E; Stelinski, Lukasz L; Stansly, Philip A

2013-01-01

187

Population changes of nematodes associated with Citrus reticulata and Citrus aurantifolia  

Microsoft Academic Search

Two economically important species of Citrus fruits viz., orange, Citrus reliculata and lemon, C. aurantifolia were selected for studying the changes in the population of plant parasitic nematodes around their roots. The nematode population of Hoplolaimus indicus, Helicotylenchus indicus, Xiphinema americanum, Pratylenchus coffeae, Tylenchulus semipenetrans and Hemicriconemoides mangiferae was observed at 10?cm (upper layer) followed by 20?cm (middle) and 40?cm

Mansoor A Siddiqui

2005-01-01

188

Irradiacao de borbulhas visando a obtencao de resistencia ao cancro citrico por inducao de mutacao. (Bud irradiation to obtain resistence to citrus canker through induction of mutation).  

National Technical Information Service (NTIS)

The radiosensitivity to gamma rays of the bud of the orange cultivar Pera is determined through irradiation of buds with several doses; the irradiated buds were grafted onto rootstocks of lemon cu. Cravo. The grafting percentage and the development of the...

J. O. M. Menten J. Pompeu P. Dragone J. T. Sobrinho V. A. Prada

1989-01-01

189

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

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

Site Plan & Site Section of Citrus Landscape (Showing Relationship of Groves & Irrigation System to Grove Canal) - Arlington Heights Citrus Landscape, Southwestern portion of city of Riverside, Riverside, Riverside County, CA

190

Evaluation of Waste Citrus Activated Sludge in Poultry Feeds.  

National Technical Information Service (NTIS)

Experiments were conducted on chick broilers and hens to determine the metabolizable energy of citrus sludge. A determination of metabolizable energy values showed that the values decreased as the level of citrus sludge in the diet increased. A series of ...

B. L. Damron D. M. Janky R. H. Harms M. F. Hall

1982-01-01

191

Citrus nobiletin suppresses inducible nitric oxide synthase gene expression in interleukin-1?-treated hepatocytes  

SciTech Connect

Highlights: •Nobiletin is a polymethoxylated flavone that is abundant in citrus peels. •Nobiletin is a major constituent of the Citrus unshiu peel extract. •Nobiletin suppresses induction of NO and reduces iNOS expression in hepatocytes. •Nobiletin reduces the iNOS promoter activity and the DNA-binding activity of NF-?B. -- Abstract: Background: Nobiletin is a polymethoxylated flavone that is abundant in the peels of citrus fruits, such as Citrus unshiu (Satsuma mandarin) and Citrus sinensis. The dried peels of C. unshiu (chinpi) have been included in several formulae of Japanese Kampo medicines. Nobiletin may suppress the induction of inducible nitric oxide synthase (iNOS), which synthesizes the inflammatory mediator nitric oxide (NO) in hepatocytes. Methods: A C. unshiu peel (CUP) extract was prepared. Primary cultured rat hepatocytes were treated with the CUP extract or nobiletin in the presence of interleukin 1? (IL-1?), which induces iNOS expression. NO production and iNOS gene expression were analyzed. Results: High-performance liquid chromatography analyses revealed that the nobiletin content in the CUP extract was 0.14%. Nobiletin dose-dependently reduced the NO levels and decreased iNOS expression at the protein, mRNA and antisense transcript levels. Flavone, which does not contain any methoxy groups, also suppressed iNOS induction. Nobiletin reduced the transcriptional activity of iNOS promoter-luciferase constructs and the DNA-binding activity of nuclear factor ?B (NF-?B) in the nuclei. Conclusions: The suppression of iNOS induction by nobiletin suggests that nobiletin may be responsible for the anti-inflammatory effects of citrus peels and have a therapeutic potential for liver diseases.

Yoshigai, Emi [Department of Biomedical Sciences, College of Life Sciences, Kusatsu, Shiga (Japan) [Department of Biomedical Sciences, College of Life Sciences, Kusatsu, Shiga (Japan); Ritsumeikan Global Innovation Research Organization (R-GIRO), Kusatsu, Shiga (Japan); Machida, Toru [Department of Biomedical Sciences, College of Life Sciences, Kusatsu, Shiga (Japan)] [Department of Biomedical Sciences, College of Life Sciences, Kusatsu, Shiga (Japan); Okuyama, Tetsuya [Ritsumeikan Global Innovation Research Organization (R-GIRO), Kusatsu, Shiga (Japan)] [Ritsumeikan Global Innovation Research Organization (R-GIRO), Kusatsu, Shiga (Japan); Mori, Masatoshi; Murase, Hiromitsu; Yamanishi, Ryota [Department of Biomedical Sciences, College of Life Sciences, Kusatsu, Shiga (Japan)] [Department of Biomedical Sciences, College of Life Sciences, Kusatsu, Shiga (Japan); Okumura, Tadayoshi [Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga (Japan) [Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Shiga (Japan); Department of Surgery, Kansai Medical University, Hirakata, Osaka (Japan); Ikeya, Yukinobu [Department of Pharmacy, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga (Japan)] [Department of Pharmacy, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga (Japan); Nishino, Hoyoku [Ritsumeikan Global Innovation Research Organization (R-GIRO), Kusatsu, Shiga (Japan) [Ritsumeikan Global Innovation Research Organization (R-GIRO), Kusatsu, Shiga (Japan); Department of Biochemistry, Kyoto Prefectural University of Medicine, Kyoto (Japan); Nishizawa, Mikio, E-mail: nishizaw@sk.ritsumei.ac.jp [Department of Biomedical Sciences, College of Life Sciences, Kusatsu, Shiga (Japan)] [Department of Biomedical Sciences, College of Life Sciences, Kusatsu, Shiga (Japan)

2013-09-13

192

Isolation and characterization of beneficial bacteria associated with citrus roots in Florida.  

PubMed

Cultivable diversity of bacteria associated with citrus was investigated as part of a larger study to understand the roles of beneficial bacteria and utilize them to increase the productive capacity and sustainability of agro-ecosystems. Citrus roots from Huanglongbing (HLB) diseased symptomatic and asymptomatic citrus were used in this study. A total of 227 and 125 morphologically distinct colonies were isolated and characterized from HLB asymptomatic and symptomatic trees, respectively. We observed that the frequency of bacterial isolates possessing various plant beneficial properties was significantly higher in the asymptomatic samples. A total of 39 bacterial isolates showing a minimum of five beneficial traits related to mineral nutrition [phosphate (P) solubilization, siderophore production, nitrogen (N) fixation], development [indole acetic acid (IAA) synthesis], health [production of antibiotic and lytic enzymes (chitinase)], induction of systemic resistance [salicylic acid (SA) production], stress relief [production of 1-amino-cyclopropane-1-carboxylate deaminase] and production of quorum sensing [N-acyl homoserine lactones] signals were characterized. A bioassay using ethidium monoazide (EMA)-qPCR was developed to select bacteria antagonistic to Candidatus Liberibacter asiaticus. Using the modified EMA-qPCR assay, we found six bacterial isolates showing maximum similarity to Paenibacillus validus, Lysinibacillus fusiformis, Bacillus licheniformis, Pseudomonas putida, Microbacterium oleivorans, and Serratia plymutica could significantly reduce the population of viable Ca. L. asiaticus in HLB symptomatic leaf samples. In conclusion, we have isolated and characterized multiple beneficial bacterial strains from citrus roots which have the potential to enhance plant growth and suppress diseases. PMID:21360139

Trivedi, Pankaj; Spann, Timothy; Wang, Nian

2011-08-01

193

Absorption and Mobility of Boron in Young Citrus Plants  

Microsoft Academic Search

Boron (B) deficiency is widespread in Brazilian citrus orchards and has been considered an important soil constraint to citrus yield. The aim of this work was to study B uptake and its mobility in young citrus trees, under different B statuses, in two rootstocks. The experiment was carried out in a greenhouse, with ‘Valencia’ sweet orange trees budded on Rangpur

Rodrigo Marcelli Boaretto; José Antonio Quaggio; Francisco de Assis Alves Mourão Filho; Maria Fernanda Giné; Antonio Enedi Boaretto

2008-01-01

194

7 CFR 319.56-41 - Citrus from Peru.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Citrus from Peru. 319.56-41 Section 319.56-41...Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ...be imported into the United States from Peru under the following conditions:...

2010-01-01

195

7 CFR 319.56-41 - Citrus from Peru.  

Code of Federal Regulations, 2010 CFR

... 2009-01-01 false Citrus from Peru. 319.56-41 Section 319.56-41...Vegetables § 319.56-41 Citrus from Peru. Grapefruit (Citrus paradisi ...be imported into the United States from Peru under the following conditions:...

2009-01-01

196

Identification of two chilling-regulated 1-aminocyclopropane- 1-carboxylate synthase genes from citrus (Citrus sinensis Osbeck) fruit  

Microsoft Academic Search

Diurnal change in the temperature below or above 12.5 °C hastens the degreening of citrus peel and elicits the phytohormone ethylene production in citrus fruit. Ethylene triggers the degradation of chlorophyll and synthesis of carotenoids in citrus peel. To investigate if ethylene is required for the degreening of citrus peel elicited by low temperatures, we studied the chilling-regulated gene expression of

Wai Shing Wong; Wen Ning; Pei Lin Xu; Shain Dow Kung; Shang Fa Yang; Ning Li

1999-01-01

197

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

PubMed

Diaphorina citri Kuwayama (Hemiptera: Psyllidae), vectors the bacterium Candidatus Liberibacter asiaticus, one of the causal organisms of the devastating citrus disease "huanglongbing" or citrus greening. In the United States, D. citri was first discovered in Florida, in 1998. Tamarixia radiata Waterston (Hymenoptera: Eulophidae) was imported from Asia and released in Florida in 1999-2001 to improve biological control of D. citri before citrus greening was detected in Florida in 2005. Florida citrus groves were surveyed during 2006-2007 for D. citri and T. radiata. Results showed that D. citri was established in all 28 citrus groves surveyed across 16 counties. Adult populations averaged 3.52, 1.27, and 1.66 individuals per "tap" sample at locations in the central, southwest, and eastern coastal regions, respectively. A tap sample consisted of 22- by 28-cm white paper sheet (on a clipboard) held under branches selected at random that were tapped three times. Averages of 67, 44, and 45% citrus shoots infested with psyllid eggs or nymphs were obtained in the central, southwest, and eastern coastal regions, respectively. T. radiata was recovered from fourth- and fifth-instar psyllid nymphs at 26 of the 28 locations. However, apparent parasitism rates were variable and averaged < 20% during spring and summer over all locations. Incidence of parasitism increased during fall at some locations, averaging 39% in September and 56% in November in the central and southwest regions, respectively. Further efforts are warranted to enhance the biological control of D. citri and thereby reduce psyllid populations and spread of citrus greening disease. PMID:19253643

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

2009-02-01

198

Betaines in fruits of Citrus genus plants.  

PubMed

Numerous compounds, many of them osmolytes, were quantified in natural juices and in frozen concentrate juices from fruits of plants of the Citrus genus. L-proline, N-methyl-L-proline (hygric acid), N,N-dimethyl-L-proline (stachydrine), 4-hydroxy-L-prolinebetaine (betonicine), 4-hydroxy-L-proline, ?-aminobutyric acid (Gaba), 3-carboxypropyltrimethylammonium (GabaBet), N-methylnicotinic acid (trigonelline), and choline in the fruit juices of yellow orange, blood orange, lemon, mandarin, bitter orange (Citrus aurantium), chinotto (Citrus myrtifolia), and grapefruit were analyzed by sensitive HPLC-ESI-tandem mass spectrometry procedure. It was found that the most represented osmolytes in the juices, that is, L-proline, stachydrine, and betonicine, can be quantified with minimal sample preparation and short analysis time (about 1 min) also by flow injection analysis (FIA) ESI-MS/MS with the same results as obtained by HPLC ESI-MS/MS. In all of the juices, discrete amounts of choline and trigonelline were present. Conversely, GabaBet was always below detection limits. Notably, N-methyl-L-proline and 4-hydroxy-L-prolinebetaine, which were discovered for the first time in the juice of bergamot (Citrus bergamia Risso et Poit), are also present in all of the citrus juices examined. PMID:21838291

Servillo, Luigi; Giovane, Alfonso; Balestrieri, Maria Luisa; Bata-Csere, Andrea; Cautela, Domenico; Castaldo, Domenico

2011-09-14

199

[The antioxidant activity of citrus fruit peels].  

PubMed

The antioxidant properties of freeze-dried citrus fruit peels (orange, lemon, grapefruit) and methanolic extracts from the peel were studied. Freeze-dried orange peel showed the highest, lemon peel somewhat less and grapefruit peel the lowest but still remarkable antioxidant activity. This could be significantly improved by preparing methanolic extracts of the peels. Comparative examinations and autoxidation studies with the flavanon glycosides hesperidin and naringin as well as with their aglycones hesperetin and naringenin showed that the former are mainly responsible for the antioxidative activity of the citrus peel and extracts. In order to compare their antioxidative activity with that of the commercially available natural antioxidants alpha-tocopherol and ascorbylpalmitate, the freeze-dried citrus peels and their methanolic extracts should be used in higher concentrations, in consideration of their peculiar properties and complex natural composition. Furthermore, aspects of the correlation between antioxidant activity and molecular structure of the flavanones were discussed. PMID:3727631

Kroyer, G

1986-03-01

200

Characterization of basidiomycetes associated with wood rot of citrus in southern Italy.  

PubMed

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

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

2014-08-01

201

Cryogenic technologies for the long-term storage of Citrus germplasm.  

PubMed

With its beautiful trees, Citrus species have long been valued by humanity. The tasteful fruits, extensively used for nutrition, are also good for health due to the high content in vitamins, minerals, and dietary fibers. Like majority of the woody fruit plants, Citrus germplasm is conserved mainly as field collections in clonal orchards. However, such a traditional approach presents several difficulties, among which are the high cost, manual labor, and extensive land required to maintain the collections, as well as the necessity of a careful protection of plants from diseases and extreme environmental conditions. As many species in the genus have seeds recalcitrant to desiccation, conservation in seed banks is also inadequate. On the other hand, cryopreservation, i.e., the storage of specimens at ultra-low temperatures (usually in liquid nitrogen, at -196°C) where reactions within the cells are minimized, presents a unique alternative for the safe storage of such germplasm. The present contribution outlines the cryopreservation techniques applied to seeds, zygotic and somatic embryos, embryogenic callus cultures of Citrus spp. and provides sample protocols to be used for Citrus conservation. PMID:21207270

De Carlo, Anna; Lambardi, Maurizio; Ozudogru, Elif Aylin

2011-01-01

202

Phytochemistry and biological activity of Spanish Citrus fruits.  

PubMed

The evaluation of the potential inhibitory activity on ?-glucosidase and pancreatic lipase by Citrus spp. fruits of Spanish origin (lemon, orange, grapefruit, lime, and mandarin) together with the evaluation of their phytochemical content and antioxidant capacity (DPPH?, ORACFL, ABTS(+), FRAP and O2?(-)) aiming for new applications of the fruits in nutrition and health was carried out. As far as we are aware, the presence of 3-O-caffeoylferuoylquinic acid and two hydrated feruloylquinic acids in orange and the presence of 3,5-diferuoylquinic acid in grapefruit have been reported for the first time. Although grapefruit showed higher contents of phytochemicals such as flavanones and vitamin C, lemon and lime showed higher potential for inhibitory effects on lipase, and lime also showed the best results for in vitro ?-glucosidase inhibition. On the other hand, higher antioxidant capacity was reported for grapefruit, lemon and lime, which correlated well with their phytochemical composition. Based on the results, it could be concluded that Citrus fruits are of great value for nutrition and treatment of diet-related diseases such as obesity and diabetes, and consequently, a new field of interest in the food industry regarding new bioactive ingredients would be considered. PMID:24563112

Gironés-Vilaplana, Amadeo; Moreno, Diego A; García-Viguera, Cristina

2014-04-01

203

Transcriptome comparison and gene coexpression network analysis provide a systems view of citrus response to 'Candidatus Liberibacter asiaticus' infection  

PubMed Central

Background Huanglongbing (HLB) is arguably the most destructive disease for the citrus industry. HLB is caused by infection of the bacterium, Candidatus Liberibacter spp. Several citrus GeneChip studies have revealed thousands of genes that are up- or down-regulated by infection with Ca. Liberibacter asiaticus. However, whether and how these host genes act to protect against HLB remains poorly understood. Results As a first step towards a mechanistic view of citrus in response to the HLB bacterial infection, we performed a comparative transcriptome analysis and found that a total of 21 Probesets are commonly up-regulated by the HLB bacterial infection. In addition, a number of genes are likely regulated specifically at early, late or very late stages of the infection. Furthermore, using Pearson correlation coefficient-based gene coexpression analysis, we constructed a citrus HLB response network consisting of 3,507 Probesets and 56,287 interactions. Genes involved in carbohydrate and nitrogen metabolic processes, transport, defense, signaling and hormone response were overrepresented in the HLB response network and the subnetworks for these processes were constructed. Analysis of the defense and hormone response subnetworks indicates that hormone response is interconnected with defense response. In addition, mapping the commonly up-regulated HLB responsive genes into the HLB response network resulted in a core subnetwork where transport plays a key role in the citrus response to the HLB bacterial infection. Moreover, analysis of a phloem protein subnetwork indicates a role for this protein and zinc transporters or zinc-binding proteins in the citrus HLB defense response. Conclusion Through integrating transcriptome comparison and gene coexpression network analysis, we have provided for the first time a systems view of citrus in response to the Ca. Liberibacter spp. infection causing HLB.

2013-01-01

204

EFFECTS OF CITRUS TRISTEZA VIRUS ON THE GROWTH OF IN VITRO-CULTURED CITRUS  

Microsoft Academic Search

SUMMARY Citrus tristeza virus isolate YC (CTV-YC), a stem pit- ting-inducing strain, was graft-transmitted to seedlings of Mexican lime (Citrus aurantifolia (Christm.) Swingle), Pineapple sweet orange (C. sinensis (L.) Os- beck) and Arizona Etrog citron 861-SI (C. medica L.). Nodal stem segments from CTV-YC-infected and healthy seedlings of the three species were used as ex- plants for regeneration in vitro.

C. X. Wang; N. Hong; G. P. Wang; B. Jiang; X. D. Fan

2009-01-01

205

Transcriptional response of Citrus aurantifolia to infection by Citrus tristeza virus  

Microsoft Academic Search

Changes in gene expression of Mexican lime plants in response to infection with a severe (T305) or a mild (T385) isolate of Citrus tristeza virus (CTV) were analyzed using a cDNA microarray containing 12,672 probes to 6875 different citrus genes. Statistically significant (P<0.01) expression changes of 334 genes were detected in response to infection with isolate T305, whereas infection with

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

2007-01-01

206

Comparative Investigation of the Distilled Lime Oils (Citrus aurantifolia Swingle and Citrus latifolia Tanaka) from Cuba  

Microsoft Academic Search

Commercial distilled oils produced from Citrus aurantifolia Swingle and Citrus latifolia Tanaka were analyzed by GC\\/MS. The oils shows remarkable differences, large engough to explain those found in odor and flavor. In both oils, limonene (40.4% and 55.6%), ?-terpinene (9.5% and 11.8%), terpinolene (8.7% and 5.2%) and ?-terpineol (12.7% and 6.6%) were the major constituents, respectively

Jorge A. Pino; Arístides Rosado

2001-01-01

207

Profiles of Essential Oils of Peel and Leaf of a New Citrus Hybrid, Citrus latifolia Tanaka x Citrus aurantifolia Swingle  

Microsoft Academic Search

The essential oil profiles of peel and leaf oils of a new Citrus hybrid and its parents, the triploid seedless lime and the diploid Kagzi lime, were established after resolving the oil using capillary GC. The chemical composition of hybrid oil was discussed in comparison with that of its parents. The analytical properties of hybrid peel oil were found to

Y. Selvaraj; M. B. N. V. Prasad; G. Venkateshwarlu

2002-01-01

208

Impacts of horticultural mineral oils and two insecticide practices on population fluctuation of Diaphorina citri and spread of Huanglongbing in a citrus orchard in Sarawak.  

PubMed

Aspects of the incidence and spread of the citrus disease huanglongbing (HLB) in relation to the vector Diaphorina citri population fluctuation were studied from January 1999 to December 2001 seasons in a 0.8 ha citrus orchard at Jemukan (1° 33'N, 110° 41'E), Southwest Sarawak in Malaysia. In relation to insecticide and horticultural mineral oils (HMOs) use, levels of HLB infection rose quite rapidly over the next 3 years in the unsprayed control and less rapidly in the other treatments such as imidacloprid, nC24HMO, and triazophos/cypermethrin/chlorpyrifos. Levels of HLB as determined by Polymerase Chain Reaction (PCR) were 42.2%, 9.4%, 11.4%, and 22.7%, respectively. The effects of nC(24)HMO and conventional pesticides on the citrus psyllid population and parasitoids in citrus orchard were also determined. PMID:22629178

Leong, Stephen Chan Teck; Abang, Fatimah; Beattie, Andrew; Kueh, Roland Jui Heng; Wong, Sing King

2012-01-01

209

Impacts of Horticultural Mineral Oils and Two Insecticide Practices on Population Fluctuation of Diaphorina citri and Spread of Huanglongbing in a Citrus Orchard in Sarawak  

PubMed Central

Aspects of the incidence and spread of the citrus disease huanglongbing (HLB) in relation to the vector Diaphorina citri population fluctuation were studied from January 1999 to December 2001 seasons in a 0.8?ha citrus orchard at Jemukan (1° 33?N, 110° 41?E), Southwest Sarawak in Malaysia. In relation to insecticide and horticultural mineral oils (HMOs) use, levels of HLB infection rose quite rapidly over the next 3 years in the unsprayed control and less rapidly in the other treatments such as imidacloprid, nC24HMO, and triazophos/cypermethrin/chlorpyrifos. Levels of HLB as determined by Polymerase Chain Reaction (PCR) were 42.2%, 9.4%, 11.4%, and 22.7%, respectively. The effects of nC24HMO and conventional pesticides on the citrus psyllid population and parasitoids in citrus orchard were also determined.

Leong, Stephen Chan Teck; Abang, Fatimah; Beattie, Andrew; Kueh, Roland Jui Heng; Wong, Sing King

2012-01-01

210

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

PubMed Central

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

Wang, Rui; Shi, Xue-gen; Wei, You-zhang; Yang, Xiao-e; Uoti, Juhani

2006-01-01

211

Volatile constituents of wild citrus Mangshanyegan (Citrus nobilis Lauriro) peel oil.  

PubMed

Volatiles of a wild mandarin, Mangshanyegan (Citrus nobilis Lauriro), were characterized by GC-MS, and their aroma active compounds were identified by aroma extract dilution analysis (AEDA) and gas chromatography-olfactometry (GC-O). The volatile profile of Mangshanyegan was compared with those of other four citrus species, Kaopan pummelo (Citrus grandis), Eureka lemon (Citrus limon), Huangyanbendizao tangerine (Citrus reticulata), and Seike navel orange (Citrus sinensis). Monoterpene hydrocarbons predominated in Mangshanyegan, in particular d-limonene and ?-myrcene, which accounted for 85.75 and 10.89% of total volatiles, respectively. Among the 12 compounds with flavor dilution factors (FD) = 27, 8 oxygenated compounds, including (Z)- and (E)-linalool oxides, were present only in Mangshanyegan. The combined results of GC-O, quantitative analysis, odor activity values (OAVs), and omission tests revealed that ?-myrcene and (Z)- and (E)-linalool oxides were the characteristic aroma compounds of Mangshanyegan, contributing to the balsamic and floral notes of its aroma. PMID:22352344

Liu, Cuihua; Cheng, Yunjiang; Zhang, Hongyan; Deng, Xiuxin; Chen, Feng; Xu, Juan

2012-03-14

212

Application of protoplast fusion to citrus breeding  

Microsoft Academic Search

Protoplast fusion in higher plants is a useful technique for production of novel plants which cannot be obtained by conventional breeding methods. For more than a decade, successful somatic hybridization was limited to herbaceous plants. In Citrus, the use of nucellar callus obtained from ovules, possessing high regeneration ability, made it possible to regenerate whole plants from protoplasts. Then, somatic

T. Ohgawara; S. Kobayashi

1991-01-01

213

Organic Citrus: Soil Fertility and Plant Nutrition  

Microsoft Academic Search

Increasing realization of the ill effects of long sustained, exclusive use of chemical fertilizers, and consistent growing demand from the consumers for fruit quality, coupled with unsustainable productivity of citrus, have fostered experimentation with some alternative cultural practices. Organic culture is claimed to be the most benign alternative. Use of organic materials such as farmyard manure, cakes of plant origin,

A. K. Srivastava; Shyam Singh; R. A. Marathe

2002-01-01

214

Soil variables vs. mineral analyses of citrus  

Microsoft Academic Search

Leaf and root samples from 120 citrus trees, representing four species from each of six different locations in Egypt, were assayed for mineral elements with an emission spectrograph. The areas represented newly reclaimed lands as well as established orchards in the Nile River Delta. There were symptoms of Zn, Mn, and Fe deficiencies at some, but not all, of the

A. Wallace; M. Naguib; E. M. Romney; G. V. Alexander

1977-01-01

215

Use of Ozone in the Citrus Industry  

Microsoft Academic Search

The use of ozone for postharvest sanitation and decay control of fruits, vegetables and their products during handling, processing and storage has been investigated for commercial applications. Due to their significant contribution to world trade and human nutrition, citrus fruits are thought to be important commodities. Decay can be observed in these products because of microbial activity and ethylene accumulation

Hakan Karaca

2010-01-01

216

Euserica modesta Fairmaire (Coleoptera: Scarabaeidae): a new record for a chafer insect pest attacking citrus orchards in Egypt  

Microsoft Academic Search

Many pests and diseases are widely spread and attack several plants and agricultural products. During September 2008, a new chafer insect pest, Euserica modesta Fairmaire (Coleoptera: Scarabaeidae) was recorded for the first time in the south Sinai region, north of Egypt. This insect was shown to attack and destroy flowers and leaves of citrus orchards. It was identified by the

A. S. H. Abdel-Moniem

2011-01-01

217

Euserica modesta Fairmaire (Coleoptera: Scarabaeidae): a new record for a chafer insect pest attacking citrus orchards in Egypt  

Microsoft Academic Search

Many pests and diseases are widely spread and attack several plants and agricultural products. During September 2008, a new chafer insect pest, Euserica modesta Fairmaire (Coleoptera: Scarabaeidae) was recorded for the first time in the south Sinai region, north of Egypt. This insect was shown to attack and destroy flowers and leaves of citrus orchards. It was identified by the

A. S. H. Abdel-Moniem

2010-01-01

218

Effects of elevated atmospheric CO 2 on two southern forest diseases  

Microsoft Academic Search

Research into the effects of rising atmospheric carbon dioxide (CO2) on plant diseases remains limited despite the economic importance of this subject. Loblolly pine (Pinus taeda) seedlings were exposed to ambient and twice ambient levels of atmospheric CO2 prior to inoculation with the fusiform rust fungus (the obligate pathogen Cronartium quercuum f.sp. fusiforme, CQF) or the pitch canker fungus (the

G. B. Runion; S. A. Prior; H. H. Rogers; R. J. Mitchell

2010-01-01

219

Huanglongbing alters the structure and functional diversity of microbial communities associated with citrus rhizosphere.  

PubMed

The diversity and stability of bacterial communities present in the rhizosphere heavily influence soil and plant quality and ecosystem sustainability. The goal of this study is to understand how 'Candidatus Liberibacter asiaticus' (known to cause Huanglongbing, HLB) influences the structure and functional potential of microbial communities associated with the citrus rhizosphere. Clone library sequencing and taxon/group-specific quantitative real-time PCR results showed that 'Ca. L. asiaticus' infection restructured the native microbial community associated with citrus rhizosphere. Within the bacterial community, phylum Proteobacteria with various genera typically known as successful rhizosphere colonizers were significantly greater in clone libraries from healthy samples, whereas phylum Acidobacteria, Actinobacteria and Firmicutes, typically more dominant in the bulk soil were higher in 'Ca. L. asiaticus'-infected samples. A comprehensive functional microarray GeoChip 3.0 was used to determine the effects of 'Ca. L. asiaticus' infection on the functional diversity of rhizosphere microbial communities. GeoChip analysis showed that HLB disease has significant effects on various functional guilds of bacteria. Many genes involved in key ecological processes such as nitrogen cycling, carbon fixation, phosphorus utilization, metal homeostasis and resistance were significantly greater in healthy than in the 'Ca. L. asiaticus'-infected citrus rhizosphere. Our results showed that the microbial community of the 'Ca. L. asiaticus'-infected citrus rhizosphere has shifted away from using more easily degraded sources of carbon to the more recalcitrant forms. Overall, our study provides evidence that the change in plant physiology mediated by 'Ca. L. asiaticus' infection could elicit shifts in the composition and functional potential of rhizosphere microbial communities. In the long term, these fluctuations might have important implications for the productivity and sustainability of citrus-producing agro-ecosystems. PMID:21796220

Trivedi, Pankaj; He, Zhili; Van Nostrand, Joy D; Albrigo, Gene; Zhou, Jizhong; Wang, Nian

2012-02-01

220

New genes of Xanthomonas citri subsp. citri involved in pathogenesis and adaptation revealed by a transposon-based mutant library  

PubMed Central

Background Citrus canker is a disease caused by the phytopathogens Xanthomonas citri subsp. citri, Xanthomonas fuscans subsp. aurantifolli and Xanthomonas alfalfae subsp. citrumelonis. The first of the three species, which causes citrus bacterial canker type A, is the most widely spread and severe, attacking all citrus species. In Brazil, this species is the most important, being found in practically all areas where citrus canker has been detected. Like most phytobacterioses, there is no efficient way to control citrus canker. Considering the importance of the disease worldwide, investigation is needed to accurately detect which genes are related to the pathogen-host adaptation process and which are associated with pathogenesis. Results Through transposon insertion mutagenesis, 10,000 mutants of Xanthomonas citri subsp. citri strain 306 (Xcc) were obtained, and 3,300 were inoculated in Rangpur lime (Citrus limonia) leaves. Their ability to cause citrus canker was analyzed every 3 days until 21 days after inoculation; a set of 44 mutants showed altered virulence, with 8 presenting a complete loss of causing citrus canker symptoms. Sequencing of the insertion site in all 44 mutants revealed that 35 different ORFs were hit, since some ORFs were hit in more than one mutant, with mutants for the same ORF presenting the same phenotype. An analysis of these ORFs showed that some encoded genes were previously known as related to pathogenicity in phytobacteria and, more interestingly, revealed new genes never implicated with Xanthomonas pathogenicity before, including hypothetical ORFs. Among the 8 mutants with no canker symptoms are the hrpB4 and hrpX genes, two genes that belong to type III secretion system (TTSS), two hypothetical ORFS and, surprisingly, the htrA gene, a gene reported as involved with the virulence process in animal-pathogenic bacteria but not described as involved in phytobacteria virulence. Nucleic acid hybridization using labeled cDNA probes showed that some of the mutated genes are differentially expressed when the bacterium is grown in citrus leaves. Finally, comparative genomic analysis revealed that 5 mutated ORFs are in new putative pathogenicity islands. Conclusion The identification of these new genes related with Xcc infection and virulence is a great step towards the understanding of plant-pathogen interactions and could allow the development of strategies to control citrus canker.

2009-01-01

221

Naringenin from Citrus junos Has an Inhibitory Effect on Acetylcholinesterase and a Mitigating Effect on Amnesia  

Microsoft Academic Search

This study was performed to identify safe and more effective acetylcholinesterase (AChE) inhibitors in the treatment of Alzheimer’s disease. The total methanol extract of Citrus junos had a significant inhibitory effect on AChE in vitro. By sequential fractionation of C. junos, the active component was finally identified as naringenin. Naringenin inhibited AChE activity in a dose-dependent manner. In this study,

Ho Jin Heo; Mi-Jeong Kim; Jung-Min Lee; Soo Jung Choi; Hong-Yon Cho; Bumshik Hong; Hye-Kyung Kim; Eunki Kim; Dong-Hoon Shin

2004-01-01

222

Agricultural pathogen decontamination technology-reducing the threat of infectious agent spread  

Microsoft Academic Search

Outbreaks of infectious agricultural diseases, whether natural occurring or introduced intentionally, could have catastrophic impacts on the U.S. economy. Examples of such agricultural pathogens include foot and mouth disease (FMD), avian influenza (AI), citrus canker, wheat and soy rust, etc. Current approaches to mitigate the spread of agricultural pathogens include quarantine, development of vaccines for animal diseases, and development of

Rita G. Betty; Jill Marie Bieker; Mark David Tucker

2005-01-01

223

Infrared spectroscopy: a potential tool in huanglongbing and citrus variegated chlorosis diagnosis.  

PubMed

Huanglongbing (HLB) and citrus variegated chlorosis (CVC) are serious threats to citrus production and have caused considerable economic losses worldwide, especially in Brazil, which is one of the biggest citrus producers in the world. Neither disease has a cure nor an efficient means of control. They are also generally confused with each other in the field since they share similar initial symptoms, e.g., yellowing blotchy leaves. The most efficient tool for detecting these diseases is by polymerase chain reaction (PCR). However, PCR is expensive, is not high throughput, and is subject to cross reaction and contamination. In this report, a diagnostic method is proposed for detecting HLB and CVC diseases in leaves of sweet orange trees using attenuated total reflectance Fourier transform infrared spectroscopy and the induced classifier via partial least-squares regression. Four different leaf types were considered: healthy, CVC-symptomatic, HLB-symptomatic, and HLB-asymptomatic. The results show a success rate of 93.8% in correctly identifying these different leaf types. In order to understand which compounds are responsible for the spectral differences between the leaf types, samples of carbohydrates starch, sucrose, and glucose, flavonoids hesperidin and naringin, and coumarin umbelliferone were also analyzed. The concentration of these compounds in leaves may vary due to biotic stresses. PMID:22365672

Cardinali, Marcelo Camponez do Brasil; Villas Boas, Paulino Ribeiro; Milori, Débora Marcondes Bastos Pereira; Ferreira, Ednaldo José; França e Silva, Marina; Machado, Marcos Antonio; Bellete, Barbara Sayuri; da Silva, Maria Fatima das Graças Fernandes

2012-03-15

224

Citrus tissue culture employing vegetative explants.  

PubMed

Citrus being a number one fruit of the world due to its high nutritional value, huge production of fruits and fruit products, the citrus industry may be considered a major fruit industry. Though citrus orchard area in India is comparable to USA, the produce is far less, while its export is nil. Biotechnology has played an outstanding role in boosting the citrus industry, e.g., in Spain, which is now the biggest exporter of citrus fruit with the application of micrografting. Amongst the fruit trees, perhaps the maximum tissue culture research has been done in citrus during the past four decades, however, the results of practical value are meagre. The shortfalls in citrus tissue culture research and some advancements made in this direction along with bright prospects are highlighted, restricting the review to vegetative explants only. Whilst utilization of nucellar embryogenesis is limited to rootstocks, the other aspects, like, regeneration and proliferation of shoot meristems measuring 200 microm in length--a global breakthrough--of two commercially important scion species, Citrus aurantifolia and C. sinensis and an important rootstock, C. limonia, improvement of micrografting technique, cloning of the same two scion species as well as some Indian rootstock species, employing nodal stem segments of mature trees, of immense practical value have been elaborated. A rare phenomenon of shift in the morphogenetic pattern of differentiation from shoot bud differentiation to embryoid formation occurred during the long-term culture of stem callus of C. grandis. Stem callus-regenerated plants of C. aurantifolia, C. sinensis and C. grandis showed variation in their ploidy levels and a somaclonal variant of C. sinensis, which produced seedless fruits was isolated. Tailoring of rooting in microshoots to a tap root-like system by changing the inorganic salt composition of the rooting medium, resulting in 100% transplant success, and germplasm preservation through normal growth culture of shoots of C grandis without loss of regeneration capacity during 31 years, observed so far, are some other significant results. Plants of C. aurantifolia and C. sinensis raised from shoot meristem and micrografting were grown in a nethouse and those from nodal stem segments in the field along with the in vitro-raised plants of rootstocks, namely, C. jambhiri, C. karna and C. limonia. All the plants showed normal healthy growth. Significantly enough, the meristem regenerated plants of C. aurantifolia attained the reproductive phase just in 1 year of transplantation to soil similar to those raised from nodal stem segments of mature trees, which also produced normal fruits in the subsequent year while growing under field conditions. Thus, a significant fundamental concept of a maturity factor, carried over through as small a shoot meristem as 200 microm in length to cloned plants has been demonstrated. The concept is of far-reaching significance in citrus industry besides production of pathogen-free orchards. PMID:11906099

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

2001-11-01

225

Rapid separation method of polymethoxyflavones from citrus using flash chromatography  

Microsoft Academic Search

Polymethoxyflavones (PMF’s) are a sub class of flavonoids, present in citrus species. Due to their potential use as a chemopreventive agent based on in vitro studies, a rapid reproducible method for the purification of PMF’s is critical. In the present study, a rapid separation method of PMF’s from Cleopatra mandarin (Citrus reshni Hort. ex Tan.) and Marrs sweet orange (Citrus

Ram M. Uckoo; Guddadarangavvanahally K. Jayaprakasha; Bhimanagouda S. Patil

2011-01-01

226

[Effect of ecological factors on citrus fruit quality].  

PubMed

This paper summarized the research advance on the physiological foundation of citrus fruit's major quality factors such as color formation and organic acid and sugar accumulation, and analyzed the effects of main ecological factors such as temperature, sunshine, water, soil, terrain and landforms on them. The existing problems and the research prospects of citrus ecology were expounded, and a useful proposal on the quality sub-distribution of citrus in China was put forward. PMID:15574012

Bao, Jiangfeng; Xia, Renxue; Peng, Shu'ang

2004-08-01

227

Study on citrus response to huanglongbing highlights a down-regulation of defense-related proteins in lemon plants upon 'Ca. Liberibacter asiaticus' infection.  

PubMed

Citrus huanglongbing (HLB) is a highly destructive disease of citrus presumably caused by 'Candidatus Liberibacterasiaticus' (Las), a gram-negative, insect-transmitted, phloem-limited ?-proteobacterium. Although almost all citrus plants are susceptible to HLB, reports have shown reduced susceptibility to Las infection in lemon (Citrus limon) plants. The aim of this study is to identify intra-species specific molecular mechanisms associated with Las-induced responses in lemon plants. To achieve this, comparative 2-DE and mass spectrometry, in addition to Inductively Coupled Plasma Spectroscopy (ICPS) analyses, were applied to investigate differences in protein accumulation and the concentrations of cationic elements in leaves of healthy and Las-infected lemon plants. Results showed a differential accumulation of 27 proteins, including an increase in accumulation of starch synthase but decrease in the production of photosynthesis-related proteins in Las-infected lemon plants compared to healthy plants. Furthermore, there was a 6% increase (P > 0.05) in K concentration in leaves of lemon plants upon Las infection, which support results from previous studies and might represent a common response pattern of citrus plants to Las infection. Interestingly, contrary to reports from prior studies, this study showed a general reduction in the production of defense-related pathogen-response proteins but a 128% increase in Zn concentration in lemon plants in response to Las infection. Taken together, this study sheds light on general and intra-species specific responses associated with the response of citrus plants to Las. PMID:23922636

Nwugo, Chika C; Duan, Yongping; Lin, Hong

2013-01-01

228

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

PubMed

The spatial distribution of the citrus mealybug, Planococcus citri (Risso) (Homoptera: Pseudococcidae), was studied in citrus groves in northeastern Spain. Constant precision sampling plans were designed for all developmental stages of citrus mealybug under the fruit calyx, for late stages on fruit, and for females on trunks and main branches; more than 66, 286, and 101 data sets, respectively, were collected from nine commercial fields during 1992-1998. Dispersion parameters were determined using Taylor's power law, giving aggregated spatial patterns for citrus mealybug populations in three locations of the tree sampled. A significant relationship between the number of insects per organ and the percentage of occupied organs was established using either Wilson and Room's binomial model or Kono and Sugino's empirical formula. Constant precision (E = 0.25) sampling plans (i.e., enumerative plans) for estimating mean densities were developed using Green's equation and the two binomial models. For making management decisions, enumerative counts may be less labor-intensive than binomial sampling. Therefore, we recommend enumerative sampling plans for the use in an integrated pest management program in citrus. Required sample sizes for the range of population densities near current management thresholds, in the three plant locations calyx, fruit, and trunk were 50, 110-330, and 30, respectively. Binomial sampling, especially the empirical model, required a higher sample size to achieve equivalent levels of precision. PMID:16813342

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

2006-06-01

229

Contextual view showing northeastern eucalyptus windbreak and portion of citrus ...  

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

Contextual view showing northeastern eucalyptus windbreak and portion of citrus orchard. Camera facing 118" east-southeast. - Goerlitz House, 9893 Highland Avenue, Rancho Cucamonga, San Bernardino County, CA

230

Penicillium digitatum metabolites on synthetic media and citrus fruits.  

PubMed

Penicillium digitatum has been cultured on citrus fruits and yeast extract sucrose agar media (YES). Cultivation of fungal cultures on solid medium allowed the isolation of two novel tryptoquivaline-like metabolites, tryptoquialanine A (1) and tryptoquialanine B (2), also biosynthesized on citrus fruits. Their structural elucidation is described on the basis of their spectroscopic data, including those from 2D NMR experiments. The analysis of the biomass sterols led to the identification of 8-12. Fungal infection on the natural substrates induced the release of citrus monoterpenes together with fungal volatiles. The host-pathogen interaction in nature and the possible biological role of citrus volatiles are also discussed. PMID:12381117

Ariza, Marta R; Larsen, Thomas O; Peterson, Bent O; Duus, Jens O; Barrero, Alejandro F

2002-10-23

231

Sensitive and robust detection of citrus greening (huanglongbing) bacterium "Candidatus Liberibacter asiaticus" by DNA amplification with new 16S rDNA-specific primers.  

PubMed

Citrus greening disease is caused by "Candidatus Liberibacter spp.," including "Candidatus Liberibacter asiaticus (Las)." For detecting this disease, we designed new primers from the Las 16S rDNA and used a very small DNA template for PCR. More Las-infected tissues were detected with our primers than with the common primers. PMID:22728344

Fujikawa, Takashi; Iwanami, Toru

2012-10-01

232

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

PubMed

Huanglongbing (HLB), considered the most serious citrus disease in the world, is associated with the nonculturable bacterium 'Candidatus Liberibacter asiaticus' (Las). Infection of citrus by this pathogen leads to reduced plant vigor and productivity, ultimately resulting in death of the infected tree. It can take up to two years following initial infection before outward symptoms become apparent, making detection difficult. The existing knowledge gap in our understanding of Las and its pathogenesis leading to HLB has stymied development of treatments and methods to mitigate the pathogen's influence. To evaluate the influence of Las on fruit quality in both symptomatic and asymptomatic fruit, and gain further insight into the pathogenesis of the disease, a 1H NMR metabolomics investigation, complemented with physicochemical and analyte-specific analyses, was undertaken. Comparison of the juice obtained from oranges gathered from Las+ (symptomatic and asymptomatic) and Las- (healthy) trees revealed significant differences in the concentrations of sugars, amino and organic acids, limonin glucoside, and limonin. This study demonstrates differing metabolic profiles in the juice of oranges from Las+ and Las- and proposes how Las may be able to evade citrus defense responses. PMID:22698301

Slisz, Anne M; Breksa, Andrew P; Mishchuk, Darya O; McCollum, Greg; Slupsky, Carolyn M

2012-08-01

233

Transcriptional response of susceptible and tolerant citrus to infection with Candidatus Liberibacter asiaticus.  

PubMed

Candidatus Liberibacter asiaticus (Las), a non-culturable phloem-limited bacterium, is the suspected causal agent of huanglongbing (HLB) in Florida. HLB is one of the most devastating diseases of citrus and no resistant cultivars have been identified to date, though tolerance has been observed in the genus Poncirus and some of its hybrids. This study compares transcriptional changes in tolerant US-897 (Citrus reticulata Blanco×Poncirus trifoliata L. Raf.) and susceptible 'Cleopatra' mandarin (C. reticulata) seedlings in response to infection with Las using the Affymetrix GeneChip citrus array, with the main objective of identifying genes associated with tolerance to HLB. Microarray analysis identified 326 genes which were significantly upregulated by at least 4-fold in the susceptible genotype, compared with only 17 genes in US-897. Exclusively upregulated in US-897 was a gene for a 2-oxoglutarate (2OG) and Fe(II)-dependant oxygenase, an important enzyme involved in the biosynthesis of plant secondary metabolites. More than eight hundred genes were expressed at much higher levels in US-897 independent of infection with Las. Among these, genes for a constitutive disease resistance protein (CDR1) were notable. The possible involvement of these and other detected genes in tolerance to HLB and their possible use for biotechnology are discussed. PMID:22325873

Albrecht, Ute; Bowman, Kim D

2012-04-01

234

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

PubMed

Wolbachia is a symbiont intensively studied due to its ability to interfere with their host's reproduction, and it has been recently proposed as an alternative tool to control insect pests or vectors of diseases. The Asian citrus psyllid Diaphorina citri is an important pest of citrus since it vectors the bacterium that causes the "Huanglongbing" disease in citrus. The frequency and diversity of Wolbachia associated with D. citri is unknown, limiting the utilization of Wolbachia as an alternative strategy for insect management. Thus, we aimed to determine the natural rate of infection, to characterize the Wolbachia strains associated with this psyllid by "multilocus sequencing typing" (MLST) and wsp analysis, and to verify the association of the symbiont to particular genotypes of the host. Analysis indicated Wolbachia infects 100 % of all specimens tested from all 15 sampled populations. MLST revealed the occurrence of five new sequence types (STs) of Wolbachia, while analysis based on the wsp sequences indicated only four different types of Wolbachia. ST-173 was predominant, while the remaining STs were population specific. Analysis of the host-symbiont relationship did not reveal any particular association of Wolbachia and haplotypes or a decrease in nucleotide diversity of D. citri in populations in which more than one ST was recorded. The consequences of the diversity of STs reported are still unknown, but the fact that Wolbachia infection is fixed and that there is one ST with a broad distribution highlights the use of this symbiont as an alternative strategy to control D. citri. PMID:23269454

Guidolin, A S; Cônsoli, F L

2013-02-01

235

In vitro susceptibility of Erwinia amylovora (Burrill) Winslow et. al. to Citrus maxima essential oil.  

PubMed

Regulatory constraints and environmental and human health concerns have promoted the search for alternative bio-control strategies of fire blight, a destructive disease of rosaceous plants which produces serious losses in apple and pear orchards all over the world. The aim of this study was to establish the antimicrobial activity of Citrus maxima essential oil against Erwinia amylovora. An agar diffusion method was used for the screening of the inhibitory effect of Citrus maxima essential oil on bacterial strains growth. The quantitative inhibitory effect of pomelo oil on in vitro biofilm development was established by a microtiter colorimetric assay. In order to investigate the ability of pomelo oil to interfere with bacterial adherence and subsequent biofilm development on leaves obtained from different pomaceous fruit trees species and cultivars: Pyrus (Napoca, Williams), Malus (Golden Delicious) and Cydonia (Aromate), leaves were immersed in pomelo oil for 1, 2, 3, 5 and 10 minutes before exposing them to bacterial colonization. The architecture of bacterial biofilms developed on leaf surface was analyzed using Confocal Scanning Laser Microscopy (CSLM). Our results showed that Citrus maxima essential oil inhibited the development of bacterial biofilms on leaves, pomelo oil being more active on Cydonia (Aromate) leaves when the leaves were treated for 5 minutes. The results obtained from this study may contribute to the development of new bio-control agents as alternative strategies to protect fruit trees from fire blight disease. PMID:20583476

M?ru?escu, Lumini?a; Saviuc, Crina; Oprea, Eliza; Savu, Bogdan; Bucur, Marcela; Stanciu, Gheorghe; Chifiriuc, Mariana Carmen; Laz?r, Veronica

2009-01-01

236

Metabolic profiling strategy for discovery of nutritional biomarkers: proline betaine as a marker of citrus consumption123  

PubMed Central

Background: New food biomarkers are needed to objectively evaluate the effect of diet on health and to check adherence to dietary recommendations and healthy eating patterns. Objective: We developed a strategy for food biomarker discovery, which combined nutritional intervention with metabolic phenotyping and biomarker validation in a large-scale epidemiologic study. Design: We administered a standardized diet to 8 individuals and established a putative urinary biomarker of fruit consumption by using 1H nuclear magnetic resonance (NMR) spectroscopic profiling. The origin of the biomarker was confirmed by using targeted NMR spectroscopy of various fruit. Excretion kinetics of the biomarker were measured. The biomarker was validated by using urinary NMR spectra from UK participants of the INTERMAP (International Collaborative Study of Macronutrients, Micronutrients, and Blood Pressure) (n = 499) in which citrus consumption was ascertained from four 24-h dietary recalls per person. Finally, dietary patterns of citrus consumers (n = 787) and nonconsumers (n = 1211) were compared. Results: We identified proline betaine as a putative biomarker of citrus consumption. High concentrations were observed only in citrus fruit. Most proline betaine was excreted ?14 h after a first-order excretion profile. Biomarker validation in the epidemiologic data showed a sensitivity of 86.3% for elevated proline betaine excretion in participants who reported citrus consumption and a specificity of 90.6% (P < 0.0001). In comparison with noncitrus consumers, citrus consumers had lower intakes of fats, lower urinary sodium-potassium ratios, and higher intakes of vegetable protein, fiber, and most micronutrients. Conclusion: The biomarker identification and validation strategy has the potential to identify biomarkers for healthier eating patterns associated with a reduced risk of major chronic diseases. The trials were registered at clinicaltrials.gov as NCT01102049 and NCT01102062.

Heinzmann, Silke S; Brown, Ian J; Chan, Queenie; Bictash, Magda; Dumas, Marc-Emmanuel; Kochhar, Sunil; Stamler, Jeremiah; Holmes, Elaine; Elliott, Paul

2010-01-01

237

Cacao Diseases: Important Threats to Chocolate Production Worldwide Black Pod: Diverse Pathogens with a Global Impact on Cocoa Yield  

Microsoft Academic Search

Guest, D. 2007. Black pod: Diverse pathogens with a global impact on cocoa yield. Phytopathology 97:1650-1653. Pathogens of the Straminipile genus Phytophthora cause significant disease losses to global cocoa production. P. megakarya causes signifi- cant pod rot and losses due to canker in West Africa, whereas P. capsici and P. citrophthora cause pod rots in Central and South America. The

David Guest

238

Nitrogen best management practice for citrus trees  

Microsoft Academic Search

Elevated levels of nitrate-nitrogen (NO3-N) in the surficial aquifer above the drinking water quality standard, i.e. maximum contaminant limit (MCL; 10mgL?1), have been reported in some part of central Florida citrus production regions. Soils in this region are very sandy (sand content >95%), hence are vulnerable to leaching of soluble nutrients and chemicals below the rooting depth of the trees.

A. K. Alva; S. Paramasivam; T. A. Obreza; A. W. Schumann

2006-01-01

239

Hormonal Modulation of Citrus Responses to Flooding  

Microsoft Academic Search

In this work, variations in endogenous levels of several hormones were measured in citrus under conditions of continuous flooding\\u000a following a time-course design. The use of three genotypes differing in their ability to tolerate waterlogging has allowed\\u000a the discrimination between common and specific hormonal responses. Data suggest an essential involvement of the aerial part\\u000a in the regulation of tolerance to

Vicent Arbona; Aurelio Gómez-Cadenas

2008-01-01

240

Citrus rootstock responses to water stress  

Microsoft Academic Search

Tolerance to drought-stress (DS) of the citrus rootstock Forner–Alcaide no. 5 (FA-5) was tested and compared with that of its parents, Cleopatra mandarin (CM) and Poncirus trifoliata (PT). Nine-month-old seedlings of CM, PT and FA-5 and 15-month-old grafted trees of ‘Valencia’ orange scions on these three rootstocks were cultivated in sand under glasshouse conditions and irrigated with a nutrient solution.

Juan Rodríguez-Gamir; Eduardo Primo-Millo; Juan B. Forner; M. Angeles Forner-Giner

2010-01-01

241

Comparison of evapotranspiration rates for flatwoods and ridge citrus  

USGS Publications Warehouse

Florida citrus groves are typically grown in two regions of the state: flatwoods and ridge. The southern flatwoods citrus area has poorly drained fine textured sands with low organic matter in the shallow root zone. Ridge citrus is located in the northern ridge citrus zone and has fine to coarse textured sands with low water-holding capacity. Two commercial citrus groves, selected from each region, were studied from 15 July 2004 to 14 July 2005. The flatwoods citrus (FC) grove had a grass cover and used drainage ditches to remove excess water from the root zone. The ridge citrus (RC) grove had a bare soil surface with weeds periodically eliminated by tillage. Citrus crop evapotranspiration (ETc) rates at the two citrus groves were measured by the eddy correlation method, and components in the energy balance were also examined and compared. The study period had higher than average rainfall, and as a result, the two locations had similar annual ETc rates (1069 and 1044 mm for RC and FC, respectively). The ETc rates were 59% (RC) and 47% (FC) of the rainfall amounts during the study period. The annual reference crop evapotranspiration (ETo) rates were 1180 mm for RC and 1419 mm for FC, estimated using the standardized reference evapotranspiration equation. The citrus crop coefficients (Kc, ratio of ETc to ET o) were different between the two locations because of differences in latitude, ground cover, and rainfall amounts. The Kc values ranged from 0.70 between December and March to 1.05 between July and November for RC, and from 0.65 between November and May to 0.85 between June and October for FC. The results are consistent with other Kc values reported from field studies on citrus in both Florida and elsewhere using these and alternate methods.

Jia, X.; Swancar, A.; Jacobs, J. M.; Dukes, M. D.; Morgan, K.

2007-01-01

242

Polyembryony in non-apomictic citrus genotypes  

PubMed Central

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

Aleza, Pablo; Juarez, Jose; Ollitrault, Patrick; Navarro, Luis

2010-01-01

243

Prophage-mediated dynamics of 'Candidatus Liberibacter asiaticus' populations, the destructive bacterial pathogens of citrus huanglongbing.  

PubMed

Prophages are highly dynamic components in the bacterial genome and play an important role in intraspecies variations. There are at least two prophages in the chromosomes of Candidatus Liberibacter asiaticus' (Las) Floridian isolates. Las is both unculturable and the most prevalent species of Liberibacter pathogens that cause huanglongbing (HLB), a worldwide destructive disease of citrus. In this study, seven new prophage variants resulting from two hyper-variable regions were identified by screening clone libraries of infected citrus, periwinkle and psyllids. Among them, Types A and B share highly conserved sequences and localize within the two prophages, FP1 and FP2, respectively. Although Types B and C were abundant in all three libraries, Type A was much more abundant in the libraries from the Las-infected psyllids than from the Las-infected plants, and Type D was only identified in libraries from the infected host plants but not from the infected psyllids. Sequence analysis of these variants revealed that the variations may result from recombination and rearrangement events. Conventional PCR results using type-specific molecular markers indicated that A, B, C and D are the four most abundant types in Las-infected citrus and periwinkle. However, only three types, A, B and C are abundant in Las-infected psyllids. Typing results for Las-infected citrus field samples indicated that mixed populations of Las bacteria present in Floridian isolates, but only the Type D population was correlated with the blotchy mottle symptom. Extended cloning and sequencing of the Type D region revealed a third prophage/phage in the Las genome, which may derive from the recombination of FP1 and FP2. Dramatic variations in these prophage regions were also found among the global Las isolates. These results are the first to demonstrate the prophage/phage-mediated dynamics of Las populations in plant and insect hosts, and their correlation with insect transmission and disease development. PMID:24349235

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

2013-01-01

244

Prophage-Mediated Dynamics of 'Candidatus Liberibacter asiaticus' Populations, the Destructive Bacterial Pathogens of Citrus Huanglongbing  

PubMed Central

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

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

2013-01-01

245

A graft-based chemotherapy method for screening effective molecules and rescuing huanglongbing-affected citrus plants.  

PubMed

Huanglongbing (HLB) is the most devastating disease of citrus. The global citrus industry is in urgent need of effective chemical treatments for HLB control because of its rapid spreading worldwide. Due to the fastidious nature of the pathogens, and the poor permissibility of citrus leaf surfaces, effective screening of chemicals for the HLB control can be challenging. In this study, we developed a graft-based chemotherapy method to rapidly screen potential HLB-controlling chemical compounds. In addition, we improved transmission efficiency by using the best HLB-affected scion-rootstock combination, and demonstrated the HLB bacterial titer was the critical factor in transmission. The HLB-affected lemon scions had a high titer of HLB bacterium, survival rate (83.3%), and pathogen transmission rate (59.9%). Trifoliate, a widely used commercial rootstock, had the highest survival rate (>70.0%) compared with grapefruit (52.6%) and sour orange (50.4%). Using this method, we confirmed a mixture of penicillin and streptomycin was the most effective compounds in eliminating the HLB bacterium from the HLB-affected scions, and in successfully rescuing severely HLB-affected citrus germplasms. These findings are useful not only for chemical treatments but also for graft-based transmission studies in HLB and other Liberibacter diseases. PMID:22568814

Zhang, Muqing; Powell, Charles A; Guo, Ying; Doud, Melissa S; Duan, Yongping

2012-06-01

246

Population Structure and Disease Development of Cryphonectria parasitica in European Chestnut Forests in the Presence of Natural Hypovirulence.  

PubMed

ABSTRACT The Cryphonectria parasitica populations in two 6-year-old European chestnut (Castanea sativa) coppices were investigated in southern Switzerland over a period of 4 years. Occurrence of white isolates indicating an infection with Cryphonectria hypovirus, vegetative compatibility groups (VCGs), hypovirulence conversion capacity, and mating types were used to characterize the populations. Sampling of randomly chosen cankers in the first year yielded 59% white isolates in one and 40% in the other population. The distribution of the VCGs and mating types was similar among white and orange isolates, indicating a homogeneous infection of the two populations by the hypovirus. Fourteen VCGs were found in the first population, 16 VCGs in the second. Altogether, 21 VCGs were determined. The same three VCGs dominated in both populations, comprising more than 60% of all isolates. Several VCGs were represented only by white isolates. Five of the six most common VCGs were clustered in two hypovirulence conversion groups, with almost 100% hypovirus transmission within each cluster. Repeated sampling of the same cankers in 1990, 1992, and 1994 did not reveal an increase of white isolates. The portion of blighted stems rose from 37% to about 60% in both plots within 4 years. In this time, chestnut blight killed 15% and competition an additional 21% of the sprouts. Predominantly, sprouts with low diameters at breast height were killed. The growth rate of new cankers was high in their first year and decreased gradually in the following years. A role of hypovirulence in the decline of disease severity was evident since (i) cankers yielding white isolates grew slower and killed considerably fewer sprouts than cankers with orange isolates; and (ii) the majority of the cankers yielded white isolates at least once during the 4-year observation period. PMID:18945153

Bissegger, M; Rigling, D; Heiniger, U

1997-01-01

247

Assessment of Nitrogenized Nutrition of Citrus Rootstocks Using Chlorophyll Concentrations in the Leaf  

Microsoft Academic Search

The objective of this study was to evaluate the nitrogen (N) nutrition in lemon tree rootstocks “Cravo” (Citrus limonia Osbeck) and “Volkameriano” (Citrus volkameriana Ten. e Pasq.) and mandarin tree rootstocks “Cleopatra” (Citrus reshni Hort. ex Tan.) and “Sunki” (Citrus sunki Hort. ex Tan.), using the chlorophyll concentration in the rootstock leaves, grown in 3.0 dm capacity container in a greenhouse.

Marlon Dutra Degli Esposti; Dalmo Lopes de Siqueira; Paulo Roberto Gomes Pereira; Victor Hugo Alvarez Venegas; Luiz Carlos Chamhum Salomão; José Altino Machado Filho

2003-01-01

248

Characterization of the antioxidant properties of phenolic extracts from some citrus peels  

Microsoft Academic Search

This study sought to determine the distribution of free and bound phenolics in some Nigerian citrus peels [orange (Citrus sinensis), grapefruit (Citrus paradisii) and shaddock (Citrus maxima)] and characterize the antioxidant properties. The free phenolics were extracted with 80% acetone, while the bound phenolics\\u000a were extracted from the alkaline and acid hydrolyzed residue with ethyl acetate. Free phenolic extracts had

G. Oboh; A. O. Ademosun

249

Induction of triploid Citrus plants from endosperm calli in vitro  

Microsoft Academic Search

Triploid hybrid Citrus plants were regenerated by somatic embryogenesis in vitro from endosperm derived calli. A sequence of media formulations was used to induce and support proliferation of primary callus from endosperm, to induce embryogenesis from primary callus, and to allow embryo development leading to viable plantlets. Calli were induced from cellular endosperm of Citrus sinensis (sweet orange), C. Xparadisi

F. G. Gmitter; X. B. Ling; X. X. Deng

1990-01-01

250

High efficiency Agrobacterium-mediated transformation and regeneration of citrus  

Microsoft Academic Search

A procedure for increased efficiency of production of transgenic citrus plants was developed by extending the exposure of the explants to the selection agent and by grafting in vitro the regenerated shoot apices onto seedling rootstocks. Carrizo citrange (Citrus sinensis L. Osbeck × Poncirus trifoliata L. Raf.) stem segments from in vitro grown seedlings were cocultivated with Agrobacterium tumefaciens EHA

Leandro Pena; Magdalena Cervera; José Juárez; Carmen Ortega; José A. Pina; Nuria Durán-Vila; Luis Navarro

1995-01-01

251

Isolation of Structurally Similar Citrus Flavonoids by Flash Chromatography  

Microsoft Academic Search

A rapid and efficient method for the extraction and isolation of naringin and narirutin from citrus molasses is described. Naringin and narirutin are structurally similar glucosides present in citrus molasses. The common problem in purification of plant extracts is the large number of constituents present that are similar in nature. A flash chromatographic technique has been developed for the separation

Girija Raman; G. K. Jayaprakasha; Jennifer Brodbelt; Minhee Cho; Bhimanagouda S. Patil

2004-01-01

252

Arbuscular Mycorrhizal Fungi and Acclimatization of Micropropagated Citrus  

Microsoft Academic Search

Micropropagated plantlets lack mycorrhizal symbionts and therefore present some physiological hindrances when transferred from axenic to ex vitro conditions. The purpose of the present study was to research the effects of Glomus mosseae and G. versiforme on growth, photosynthesis, and nutrient uptake of micropropagated citrus plantlets at the acclimatization stage. The two mycorrhizal fungi successfully colonized the roots of citrus

Qiang-Sheng Wu; Ying-Ning Zou; Gui-Yuan Wang

2011-01-01

253

Growth inhibitory effect of peel extract from Citrus junos  

Microsoft Academic Search

Extract from yuzu fruit peel (Citrus junos Sieb. ex Tanaka) strongly suppressed the germination of lettuce seeds while that from the peel of other citrus fruits such as navel orange (C. sinensis) and lemon (C. limon Burm. f.) had very little or no effect. The highest inhibitory activity was located in the peel followed by the segment but no significant

Shinsuke Fujihara; Tokurou Shimizu

2003-01-01

254

EVALUATION OF WASTE CITRUS ACTIVATED SLUDGE IN POULTRY FEEDS  

EPA Science Inventory

Experiments were conducted on chick broilers and hens to determine the metabolizable energy of citrus sludge. A determination of metabolizable energy values showed that the values decreased as the level of citrus sludge in the diet increased. A series of protein levels were fed t...

255

GROWER REPORTED PESTICIDE POISONINGS AMONG FLORIDA CITRUS FIELDWORKERS  

EPA Science Inventory

In a 1981 survey of 436 Florida citrus growers, 27 pesticide related poisoning incidents were reported that were to have taken place within one year of the interview date. From these reports it is possible to estimate that there are 376 citrus fieldworker poisonings per year in F...

256

Isolation of I-Quinic Acid in Citrus Fruit  

Microsoft Academic Search

THE organic acids in citrus juices are chiefly citric and malic, although tartaric and oxalic acids also have been reported in grapefruit1. In our laboratory, succinic acid was found in frozen mature oranges. Wolf2 isolated citric, malic and an unidentified acid from citrus fruit. Sinclair and Eny3 reported that in the peel malic acid predominates while citric and oxalic acids

S. V. Ting; E. J. Deszyck

1959-01-01

257

Nutritional and physicochemical characteristic of commercial Spanish citrus juices.  

PubMed

Citrus juices are perceived as healthy foods by consumers due to their richness in antioxidant compounds. Despite the large number of papers about the antioxidant activity of citrus juices, less is known about the relationship with physicochemical properties. This paper shows that the overall antioxidant activity of citrus juices is underestimated with the standard methodologies, being up to 10-times higher with the GAR method (including an in vitro gastrointestinal digestion). 70% of the antioxidant activity was found in the soluble fraction and citrus juices contributed up to 12% of the overall antioxidant intake within the Spanish diet. Physicochemical parameters, such as colour, fluorescence, 5-hydroxymethylfurfural and furfural contents, were correlated with nutritional parameters in some samples. The intake of HMF was negligible from commercial citrus juices and was absent in freshly squeezed ones. Finally, a mathematical model is developed to classify juices depending on their nature or storage conditions. PMID:24996350

Alvarez, J; Pastoriza, S; Alonso-Olalla, R; Delgado-Andrade, C; Rufián-Henares, J A

2014-12-01

258

Anti-inflammatory and wound healing potential of citrus auraptene.  

PubMed

Auraptene is the most abundant naturally occurring geranyloxycoumarin. It is primarily isolated from plants in the Rutaceae family, many of which, like citrus fruits, are used as food in many countries. Auraptene is a biologically active secondary metabolite with valuable properties. The aim of our study was to identify novel properties of auraptene with potential for managing periodontal diseases, an inflammatory disease of bacterial origin affecting the tissues surrounding and supporting the teeth. In vitro assays showed that auraptene decreased, in a dose-dependent manner, the secretion of matrix metalloproteinase 2 as well as key inflammatory mediators, including interleukin-6 (IL-6), IL-8, and chemokine (C-C motif) ligand-5 secreted by Aggregatibacter actinomycetemcomitans lipopolysaccharide-stimulated oral epithelial cells. Using gingival fibroblasts, auraptene showed a significant (P<.05) wound healing effect by its capacity to increase cell migration. In conclusion, auraptene shows promise for promoting wound healing and controlling periodontal diseases through its capacity to interfere with inflammatory mediator secretion. PMID:24070132

La, Vu Dang; Zhao, Lei; Epifano, Francesco; Genovese, Salvatore; Grenier, Daniel

2013-10-01

259

Global gene expression of Poncirus trifoliata, Citrus sunki and their hybrids under infection of Phytophthora parasitica  

PubMed Central

Background Gummosis and root rot caused by Phytophthora are among the most economically important diseases in citrus. Four F1 resistant hybrids (Pool R), and four F1 susceptible hybrids (Pool S) to P. parasitica, were selected from a cross between susceptible Citrus sunki and resistant Poncirus trifoliata cv. Rubidoux. We investigated gene expression in pools of four resistant and four susceptible hybrids in comparison with their parents 48 hours after P. parasitica inoculation. We proposed that genes differentially expressed between resistant and susceptible parents and between their resistant and susceptible hybrids provide promising candidates for identifying transcripts involved in disease resistance. A microarray containing 62,876 UniGene transcripts selected from the CitEST database and prepared by NimbleGen Systems was used for analyzing global gene expression 48 hours after infection with P. parasitica. Results Three pairs of data comparisons (P. trifoliata/C. sunki, Pool R/C. sunki and Pool R/Pool S) were performed. With a filter of false-discovery rate less than 0.05 and fold change greater than 3.0, 21 UniGene transcripts common to the three pairwise comparative were found to be up-regulated, and 3 UniGene transcripts were down-regulated. Among them, our results indicated that the selected transcripts were probably involved in the whole process of plant defense responses to pathogen attack, including transcriptional regulation, signaling, activation of defense genes participating in HR, single dominant genes (R gene) such as TIR-NBS-LRR and RPS4 and switch of defense-related metabolism pathway. Differentially expressed genes were validated by RT-qPCR in susceptible and resistant plants and between inoculated and uninoculated control plants Conclusions Twenty four UniGene transcripts were identified as candidate genes for Citrus response to P. parasitica. UniGene transcripts were likely to be involved in disease resistance, such as genes potentially involved in secondary metabolite synthesis, intracellular osmotic adjustment, signal transduction pathways of cell death, oxidative burst and defense gene expression. Furthermore, our microarray data suggest another type of resistance in Citrus-Phytophthora interaction conferred by single dominant genes (R gene) since we encountered two previously reported R genes (TIR-NBS-LRR and RPS4) upregulated in the resistant genotypes relative to susceptible. We identified 7 transcripts with homology in other plants but yet unclear functional characterization which are an interesting pool for further analyses and 3 transcripts where no significant similarity was found. This is the first microarray study addressing an evaluation of transcriptional changes in response to P. parasitica in Citrus.

2011-01-01

260

Cultivar identification of ‘Yuzu’ ( Citrus junos Sieb. ex Tanaka) and related acid citrus by leaf isozymes  

Microsoft Academic Search

Leaf extracts of 27 ‘Yuzu’ and related acid citrus cultivars were analyzed using polyacrylamide gel electrophoresis for isozyme variation of glutamate oxaloacetate transaminase (GOT) and shikimate dehydrogenase (SDH). SDH yielded 12 different isozyme phenotypes and six cultivars were discriminated by this enzyme alone. GOT produced 10 different isozyme phenotypes and four cultivars were separated. When both enzyme systems were taken

Mohammad Mizanur Rahman; Nobumasa Nito; Shiro Isshiki

2001-01-01

261

Biological activities of Korean Citrus obovoides and Citrus natsudaidai essential oils against acne-inducing bacteria.  

PubMed

This study was designed to analyze the chemical composition of Citrus obovoides (Geumgamja) and Citrus natsudaidai (Cheonyahagyul) oils and to test their biological activities. These citrus essential oils were obtained by steam distillation of fruits collected from Jeju Island, Korea, and were analyzed using gas chromatograph (GC)-flame ionization detectors (FID) and GC-MS. Limonene and gamma-terpinene were the major components of the two citrus species. To evaluate in vitro anti-acne activity, they were tested against Propionibacterium acnes and Staphylococcus epidermidis, which are involved in acne. The Geumgamja and Cheonyahagyul oils exhibited antibacterial activity against both P. acnes and S. epidermidis. Their effects on DPPH radical scavenging, superoxide anion radical scavenging, and nitric oxide radical were also assessed. Cheonyahagyul and Geumgamja exhibited only superoxide anion radical-scavenging activity. To assess their potential usefulness in future cosmetic product applications, the cytotoxic effects of the two oils were determined by colorimetric MTT assays using two animal cell lines: normal human fibroblasts and HaCaT cells. They exhibited low cytotoxicity at 0.1 microl/ml in both cell lines. In addition, they reduced P. acnes-induced secretion of interleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-alpha) in THP-1 cells, an indication of anti-inflammatory effects. Therefore, based on these results, we suggest that Geumgamja and Cheonyahagyul essential oils are attractive acne-mitigating candidates for topical application. PMID:18838824

Kim, Sang-Suk; Baik, Jong Seok; Oh, Tae-Heon; Yoon, Weon-Jong; Lee, Nam Ho; Hyun, Chang-Gu

2008-10-01

262

Heat treatment eliminates 'Candidatus Liberibacter asiaticus' from infected citrus trees under controlled conditions.  

PubMed

Huanglongbing (HLB) is one of the most destructive diseases of citrus worldwide. The three known causal agents of HLB are species of ?-proteobacteria: 'Candidatus Liberibacter asiaticus', 'Ca. L. africanus', and 'Ca. L. americanus'. Previous studies have found distinct variations in temperature sensitivity and tolerance among these species. Here, we describe the use of controlled heat treatments to cure HLB caused by 'Ca. L. asiaticus', the most prevalent and heat-tolerant species. Using temperature-controlled growth chambers, we evaluated the time duration and temperature required to suppress or eliminate the 'Ca. L. asiaticus' bacterium in citrus, using various temperature treatments for time periods ranging from 2 days to 4 months. Results of quantitative polymerase chain reaction (qPCR) after treatment illustrate significant decreases in the 'Ca. L. asiaticus' bacterial titer, combined with healthy vigorous growth by all surviving trees. Repeated qPCR testing confirmed that previously infected, heat-treated plants showed no detectable levels of 'Ca. L. asiaticus', while untreated control plants remained highly infected. Continuous thermal exposure to 40 to 42°C for a minimum of 48 h was sufficient to significantly reduce titer or eliminate 'Ca. L. asiaticus' bacteria entirely in HLB-affected citrus seedlings. This method may be useful for the control of 'Ca. Liberibacter'-infected plants in nursery and greenhouse settings. PMID:23035631

Hoffman, Michele T; Doud, Melissa S; Williams, Lisa; Zhang, Mu-Qing; Ding, Fang; Stover, Ed; Hall, David; Zhang, Shouan; Jones, Lisa; Gooch, Mark; Fleites, Laura; Dixon, Wayne; Gabriel, Dean; Duan, Yong-Ping

2013-01-01

263

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

PubMed

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

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

2013-06-01

264

Simultaneous extraction of bioactive limonoid aglycones and glucoside from Citrus aurantium L. using hydrotropy.  

PubMed

Citrus limonoids were demonstrated to possess potential biological activities in reducing the risk of certain diseases. Limonoids are present in citrus fruits in the form of aglycones and glucosides. At present, limonoid aglycones and limonoid glucosides are extracted in multiple steps using different solvents. In order to understand their potential bioactivity, it may be beneficial to isolate and purify these compounds using environment friendly methods. A new method of extraction and purification of limonoids was established using a hydrotrope polystyrene adsorbent resin. Extraction of aglycones and glucosides was achieved in a single step, using an aqueous solution of sodium cumene sulphonate (Na-CuS). Sour orange (Citrus aurantium L.) seed powder was extracted with 2 M Na-CuS solution at 45 degrees C for 6 h. The filtered extract was diluted with water and loaded on an SP 700 adsorbent column. The column was washed with distilled water to remove the hydrotrope and then eluted using water and methanol in different compositions to obtain three compounds. The structures of the isolated compounds were confirmed by NMR spectroscopy as deacetyl nomilinic acid glucoside (DNAG), deacetyl nomilin (DAN) and limonin (LIM). PMID:18533458

Dandekar, Deepak V; Jayaprakasha, Guddadarangavvanahally K; Patil, Bhimanagouda S

2008-01-01

265

Inheritance of citrus nematode resistance and its linkage with molecular markers  

Microsoft Academic Search

Eleven RAPD markers linked to a gene region conferring resistance to citrus nematodes in an intergen-eric backcross family\\u000a were identified. Two sequence- characterized amplified region markers linked to a citrus tristeza virus resistance gene and\\u000a one selected resistance gene candidate marker were evaluated for their association with citrus nematode resistance. A nematode-susceptible\\u000a citrus hybrid, LB6-2 [Clementine mandarin (Citrus reticulata)?Hamlin orange

P. Ling; L. W. Duncan; Z. Deng; D. Dunn; X. Hu; S. Huang; F. G. Gmitter Jr

2000-01-01

266

Composition of peel essential oils from four selected Tunisian Citrus species: Evidence for the genotypic influence  

Microsoft Academic Search

The peel essential oils from four selected Tunisian Citrus species: sweet orange (Citrus sinensis Osbeck), mandarin (Citrus reticulata Blanco); sour orange (Citrus aurantium L.) and pummelo (Citrus grandis Osbeck), cultivated under the same pedoclimatic and cultural conditions have been analysed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The essential oils content ranged from 1.06% to 4.62% (w\\/w) in

Karim Hosni; Nesrine Zahed; Raouf Chrif; Ines Abid; Wafa Medfei; Monem Kallel; Nadia Ben Brahim; Houcine Sebei

2010-01-01

267

[Phosphorus translocation and distribution in intercropping systems of soybean (Glycine max) and citrus (Citrus poonensis)].  

PubMed

A field mini-plot experiment was conducted on clay loamy oxisol using 32P trace technique when P fertilizer was applied in three depth soil (15, 35 and 55 cm soil layer) to compare P absorption, distribution and translocation in plant organ and soil profile under soybean and citrus monoculture and intercropping at Taoyuan Experimental Station of Agroecosystem Research of Chinese Academy of Science. Total P uptake (PT) and P accumulation in different parts (PA) of soybean were remarkably decreased under intercropping. When 32P was applied in topsoil (15 cm soil layer), 32P uptake (32PT) by soybean was significantly lower in intercropping than in monoculture. Whereas 32PT uptake by soybean was significantly greater in intercropping than in monoculture when 32P was applied in deep soil layer (35 cm or 55 cm soil layer). However, considerable difference was not observed for 32P translocation and distribution among soybean organs. 32PT uptake by citrus was much lower under intercropping than under monoculture. The P uptake by citrus newly could be transferred rapidly to aboveground and prior to active growing organ. Intercropping did not affect 32P distribution in citrus organ, but when P was applied in deep soil layer, the speed of 32P transferred to aboveground and active organ was slowed down. P mobility was strengthened in soil profile, and P of deep soil layer was promoted to move to topsoil in intercropping. The experimental results showed the optimal depth of applied P should be within 20 cm soil layer in soybean-citrus intercropping system. PMID:15146626

Zhou, Weijun; Wang, Kairong; Li, Hesong

2004-02-01

268

Geographic Distribution of Habitat, Development, and Population Growth Rates of the Asian Citrus Psyllid, Diaphorina citri, in Mexico  

PubMed Central

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

Lopez-Collado, Jose; Isabel Lopez-Arroyo, J.; Robles-Garcia, Pedro L.; Marquez-Santos, Magdalena

2013-01-01

269

[Population fluctuation of sharpshooters vectors of Xylella fastidiosa Wells et al. in commercial citrus groves in northwestern Paraná State].  

PubMed

The citrus variegated chlorosis (CVC), an important disease of citrus in Brazil, is caused by the bacterium Xylella fastidiosa Wells et al. and transmitted by xylem-feeding sharpshooters (Hemiptera: Cicadellidae). This study evaluated the fluctuation of populations of species of sharpshooters belonging to the tribes Cicadellini and Proconiini, from subfamily Cicadelinae, in a commercial sweet orange [Citrus sinensis (L.) Osb.] grove, located in the Northwest Region of Paraná State, Brazil, in four varieties: Valência, Natal, Pêra, and Folha Murcha. Sharpshooters population was monitored using yellow stick traps sampled at 15 day-intervals, in 24 traps, from November of 1999 to March of 2004. The most abundant species were Dilobopterus costalimai Young (tribe Cicadellini) and Acrogonia citrina Marucci & Cavichioli (tribe Proconiini). Both species were detected during the complete period studied, which is important because they have great potential for transmitting CVC. Thus, since more than a sharpshooter species were detected, more efforts are recommended to monitor and control these insects in citrus groves, aiming to reduce the dissemination of CVC. PMID:17607459

Nunes, William M C; Molina, Rúbia de O; de Albuquerque, Fernando A; Corazza-Nunes, Maria J; Zanutto, Carlos A; Machado, Marcos A

2007-01-01

270

Phenylethanol promotes adhesion and biofilm formation of the antagonistic yeast Kloeckera apiculata for the control of blue mold on citrus.  

PubMed

The yeast Kloeckera apiculata strain 34-9 is an antagonist with biological control activity against postharvest diseases of citrus fruit. In a previous study it was demonstrated that K. apiculata produced the aromatic alcohol phenylethanol. In the present study, we found that K. apiculata was able to form biofilm on citrus fruit and embed in an extracellular matrix, which created a mechanical barrier interposed between the wound surface and pathogen. As a quorum-sensing molecule, phenylethanol can promote the formation of filaments by K. apiculata in potato dextrose agar medium, whereas on the citrus fruit, the antagonist remains as yeast after being treated with the same concentration of phenylethanol. It only induced K. apiculata to adhere and form biofilm. Following genome-wide computational and experimental identification of the possible genes associated with K. apiculata adhesion, we identified nine genes possibly involved in triggering yeast adhesion. Six of these genes were significantly induced after phenylethanol stress treatment. This study provides a new model system of the biology of the antagonist-pathogen interactions that occur in the antagonistic yeast K. apiculata for the control of blue mold on citrus caused by Penicillium italicum. PMID:24479773

Pu, Liu; Jingfan, Fang; Kai, Chen; Chao-An, Long; Yunjiang, Cheng

2014-06-01

271

Protective Effect of Coriolus versicolor Cultivated in Citrus Extract Against Nitric Oxide-Induced Apoptosis in Human Neuroblastoma SK-N-MC Cells.  

PubMed

Nitric oxide (NO) is a reactive free radical and a messenger molecule in many physiological functions. However, excessive NO is believed to be a mediator of neurotoxicity. The medicinal plant Coriolus versicolor is known to possess anti-tumor and immune-potentiating activities. In this study, we investigated whether Coriolus versicolor possesses a protective effect against NO donor sodium nitroprusside (SNP)-induced apoptosis in the human neuroblastoma cell line SK-N-MC. We utilized 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry, 4,6-diamidino-2-phenylindole (DAPI) staining, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay, DNA fragmentation assay, reverse transcription-polymerase chain reaction (RT-PCR), Western blot analysis, and caspase-3 enzyme activity assay in SK-N-MC cells. MTT assay showed that SNP treatment significantly reduces the viability of cells, and the viabilities of cells pre-treated with the aqueous extract of Coriolus versicolor cultivated in citrus extract (CVE(citrus)) was increased. However, aqueous extract of Coriolus versicolor cultivated in synthetic medium (CVE(synthetic)) showed no protective effect and aqueous citrus extract (CE) had a little protective effect. The cell treated with SNP exhibited several apoptotic features, while those pre-treated for 1 h with CVE(citrus) prior to SNP expose showed reduced apoptotic features. The cells pre-treated for 1 h with CVE(citrus) prior to SNP expose inhibited p53 and Bax expressions and caspase-3 enzyme activity up-regulated by SNP. We showed that CVE(citrus) exerts a protective effect against SNP-induced apoptosis in SK-N-MC cells. Our study suggests that CVE(citrus) has therapeutic value in the treatment of a variety of NO-induced brain diseases. PMID:22110367

Kim, Byung-Chul; Kim, Youn-Sub; Lee, Jin-Woo; Seo, Jin-Hee; Ji, Eun-Sang; Lee, Hyejung; Park, Yong-Il; Kim, Chang-Ju

2011-06-01

272

Transcriptional and microscopic analyses of citrus stem and root responses to Candidatus Liberibacter asiaticus infection.  

PubMed

Huanglongbing (HLB) is the most destructive disease that affects citrus worldwide. The disease has been associated with Candidatus Liberibacter. HLB diseased citrus plants develop a multitude of symptoms including zinc and copper deficiencies, blotchy mottle, corky veins, stunting, and twig dieback. Ca. L. asiaticus infection also seriously affects the roots. Previous study focused on gene expression of leaves and fruit to Ca. L. asiaticus infection. In this study, we compared the gene expression levels of stems and roots of healthy plants with those in Ca. L. asiaticus infected plants using microarrays. Affymetrix microarray analysis showed a total of 988 genes were significantly altered in expression, of which 885 were in the stems, and 111 in the roots. Of these, 551 and 56 were up-regulated, while 334 and 55 were down-regulated in the stem and root samples of HLB diseased trees compared to healthy plants, respectively. Dramatic differences in the transcriptional responses were observed between citrus stems and roots to Ca. L. asiaticus infection, with only 8 genes affected in both the roots and stems. The affected genes are involved in diverse cellular functions, including carbohydrate metabolism, cell wall biogenesis, biotic and abiotic stress responses, signaling and transcriptional factors, transportation, cell organization, protein modification and degradation, development, hormone signaling, metal handling, and redox. Microscopy analysis showed the depletion of starch in the roots of the infected plants but not in healthy plants. Collapse and thickening of cell walls were observed in HLB affected roots, but not as severe as in the stems. This study provides insight into the host response of the stems and roots to Ca. L. asiaticus infection. PMID:24058486

Aritua, Valente; Achor, Diann; Gmitter, Frederick G; Albrigo, Gene; Wang, Nian

2013-01-01

273

Transcriptional and Microscopic Analyses of Citrus Stem and Root Responses to Candidatus Liberibacter asiaticus Infection  

PubMed Central

Huanglongbing (HLB) is the most destructive disease that affects citrus worldwide. The disease has been associated with Candidatus Liberibacter. HLB diseased citrus plants develop a multitude of symptoms including zinc and copper deficiencies, blotchy mottle, corky veins, stunting, and twig dieback. Ca. L. asiaticus infection also seriously affects the roots. Previous study focused on gene expression of leaves and fruit to Ca. L. asiaticus infection. In this study, we compared the gene expression levels of stems and roots of healthy plants with those in Ca. L. asiaticus infected plants using microarrays. Affymetrix microarray analysis showed a total of 988 genes were significantly altered in expression, of which 885 were in the stems, and 111 in the roots. Of these, 551 and 56 were up-regulated, while 334 and 55 were down-regulated in the stem and root samples of HLB diseased trees compared to healthy plants, respectively. Dramatic differences in the transcriptional responses were observed between citrus stems and roots to Ca. L. asiaticus infection, with only 8 genes affected in both the roots and stems. The affected genes are involved in diverse cellular functions, including carbohydrate metabolism, cell wall biogenesis, biotic and abiotic stress responses, signaling and transcriptional factors, transportation, cell organization, protein modification and degradation, development, hormone signaling, metal handling, and redox. Microscopy analysis showed the depletion of starch in the roots of the infected plants but not in healthy plants. Collapse and thickening of cell walls were observed in HLB affected roots, but not as severe as in the stems. This study provides insight into the host response of the stems and roots to Ca. L. asiaticus infection.

Aritua, Valente; Achor, Diann; Gmitter, Frederick G.; Albrigo, Gene; Wang, Nian

2013-01-01

274

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

PubMed

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

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

2014-04-01

275

The position of the major QTL for Citrus tristeza virus resistance is conserved among Citrus grandis , C. aurantium and Poncirus trifoliata  

Microsoft Academic Search

Citrus tristeza virus, CTV, is one of the most important citrus pathogens. Although CTV-resistant citrus rootstocks derived from Poncirus trifoliata are common, useful genetic resistance within the genus Citrus for scion improvement is very limited and no CTV-resistant sweet orange cultivar is yet available. Quantitative trait locus\\u000a (QTL) analysis of the accumulation and distribution of CTV was carried out in

Maria J. Asins; Jorge Fernández-Ribacoba; Guillermo P. Bernet; José Gadea; Mariano Cambra; María T. Gorris; Emilio A. Carbonell

276

Citrus tristeza virus: a pathogen that changed the course of the citrus industry.  

PubMed

Citrus tristeza virus (CTV) (genus Closterovirus, family Closteroviridae) is the causal agent of devastating epidemics that changed the course of the citrus industry. Adapted to replicate in phloem cells of a few species within the family Rutaceae and to transmission by a few aphid species, CTV and citrus probably coevolved for centuries at the site of origin of citrus plants. CTV dispersal to other regions and its interaction with new scion varieties and rootstock combinations resulted in three distinct syndromes named tristeza, stem pitting and seedling yellows. The first, inciting decline of varieties propagated on sour orange, has forced the rebuilding of many citrus industries using tristeza-tolerant rootstocks. The second, inducing stunting, stem pitting and low bearing of some varieties, causes economic losses in an increasing number of countries. The third is usually observed by biological indexing, but rarely in the field. CTV polar virions are composed of two capsid proteins and a single-stranded, positive-sense genomic RNA (gRNA) of approximately 20 kb, containing 12 open reading frames (ORFs) and two untranslated regions (UTRs). ORFs 1a and 1b, encoding proteins of the replicase complex, are directly translated from the gRNA, and together with the 5' and 3'UTRs are the only regions required for RNA replication. The remaining ORFs, expressed via 3'-coterminal subgenomic RNAs, encode proteins required for virion assembly and movement (p6, p65, p61, p27 and p25), asymmetrical accumulation of positive and negative strands during RNA replication (p23), or suppression of post-transcriptional gene silencing (p25, p20 and p23), with the role of proteins p33, p18 and p13 as yet unknown. Analysis of genetic variation in CTV isolates revealed (1) conservation of genomes in distant geographical regions, with a limited repertoire of genotypes, (2) uneven distribution of variation along the gRNA, (3) frequent recombination events and (4) different selection pressures shaping CTV populations. Measures to control CTV damage include quarantine and budwood certification programmes, elimination of infected trees, use of tristeza-tolerant rootstocks, or cross protection with mild isolates, depending on CTV incidence and on the virus strains and host varieties predominant in each region. Incorporating resistance genes into commercial varieties by conventional breeding is presently unfeasible, whereas incorporation of pathogen-derived resistance by plant transformation has yielded variable results, indicating that the CTV-citrus interaction may be more specific and complex than initially thought. A deep understanding of the interactions between viral proteins and host and vector factors will be necessary to develop reliable and sound control measures. PMID:18705856

Moreno, Pedro; Ambrós, Silvia; Albiach-Martí, Maria R; Guerri, José; Peña, Leandro

2008-03-01

277

Study on Citrus Response to Huanglongbing Highlights a Down-Regulation of Defense-Related Proteins in Lemon Plants Upon 'Ca. Liberibacter asiaticus' Infection  

PubMed Central

Citrus huanglongbing (HLB) is a highly destructive disease of citrus presumably caused by ‘Candidatus Liberibacter asiaticus’ (Las), a gram-negative, insect-transmitted, phloem-limited ?-proteobacterium. Although almost all citrus plants are susceptible to HLB, reports have shown reduced susceptibility to Las infection in lemon (Citruslimon) plants. The aim of this study is to identify intra-species specific molecular mechanisms associated with Las-induced responses in lemon plants. To achieve this, comparative 2-DE and mass spectrometry, in addition to Inductively Coupled Plasma Spectroscopy (ICPS) analyses, were applied to investigate differences in protein accumulation and the concentrations of cationic elements in leaves of healthy and Las-infected lemon plants. Results showed a differential accumulation of 27 proteins, including an increase in accumulation of starch synthase but decrease in the production of photosynthesis-related proteins in Las-infected lemon plants compared to healthy plants. Furthermore, there was a 6% increase (P > 0.05) in K concentration in leaves of lemon plants upon Las infection, which support results from previous studies and might represent a common response pattern of citrus plants to Las infection. Interestingly, contrary to reports from prior studies, this study showed a general reduction in the production of defense-related pathogen-response proteins but a 128% increase in Zn concentration in lemon plants in response to Las infection. Taken together, this study sheds light on general and intra-species specific responses associated with the response of citrus plants to Las.

Nwugo, Chika C.; Duan, Yongping; Lin, Hong

2013-01-01

278

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

PubMed

The prevalence of sour orange rootstock in the southern and eastern part of the Mediterranean Basin is presently threatened by the spread of Citrus Tristeza Virus (CTV) and its main vector Toxoptera citricida, combined with abiotic constraints such as drought, salinity and alkalinity. The search for alternative CTV-resistant rootstocks that also withstand the other constraints is now considered an urgent priority for a sustainable citrus industry in the area. Complementary progenitors can be found in citrus germplasm to combine the desired traits, particularly between Poncirus and Citrus genera. The production of somatic hybrids allows cumulating all dominant traits irrespective of their heterozygosity level, and would appear to be an effective way to solve the rootstock challenge facing the Mediterranean citrus industry. This paper presents the results obtained during a regional collaborative effort between five countries, to develop new rootstocks by somatic hybridization. New embryogenic callus lines to be used for somatic hybridization have been created. Protoplast fusions have been performed at CIRAD and IVIA laboratories, focusing on intergeneric combinations. Analysis of ploidy level by flow cytometry and molecular markers confirmed the acquisition of new interesting tetraploid somatic hybrids for six combinations. Diploid cybrids with intergeneric (Citrus × Poncirus) nucleus and C. reticulata or C. aurantifolia mitochondria were also identified for four combinations. The agronomical performance of a pre-existing somatic hybrid between Poncirus trifoliata and Citrus reticulata was validated in calcareous soils in Morocco. Somatic hybridization is now integrated into the breeding programs of the five Mediterranean countries. PMID:21225429

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

2011-05-01

279

76 FR 78225 - Notice of Request for Extension of Approval of an Information Collection; Importation of Citrus...  

Federal Register 2010, 2011, 2012, 2013

...Collection; Importation of Citrus From Peru AGENCY: Animal and Plant Health Inspection...regulations for the importation of citrus from Peru. DATES: We will consider all comments...regulations for the importation of citrus from Peru, contact Mr. Tony...

2011-12-16

280

Rhizoctonia disease of potatoes ( Rhizoctonia solani ): Fungicidal efficacy and cultivar susceptibility  

Microsoft Academic Search

Rhizoctonia stem canker and black scurf is an economically important disease of potatoes in Alberta and around the world.\\u000a It reduces the quality and yield of potatoes and has become an important impediment for export of seed potatoes, especially\\u000a to Mexico. Seed treatment using fungicides, presently registered in Canada, are not effective in controlling the disease to\\u000a growers’ satisfaction. Field

P. S. Bains; H. S. Bennypaul; D. R. Lynch; L. M. Kawchuk; C. A. Schaupmeyer

2002-01-01

281

A rapid one-step multiplex RT-PCR assay for the simultaneous detection of five citrus viroids in China  

Microsoft Academic Search

Citrus plants are natural hosts of five viroid species and large numbers of sequence variants. In this paper a simple and\\u000a sensitive one step multiplex RT-PCR protocol with an internal control was utilised to simultaneously detect and differentiate\\u000a five citrus viroids: Citrus exocortis viroid (CEVd), Citrus bent leaf viroid (CBLVd), Hop stunt viroid (HSVd), Citrus viroid-III (CVd-III) and Citrus viroid-IV

Xuefeng Wang; Changyong Zhou; Kezhi Tang; Yan Zhou; Zhongan Li

2009-01-01

282

Analysis of 13000 unique Citrus clusters associated with fruit quality, production and salinity tolerance  

Microsoft Academic Search

Background  Improvement ofCitrus, the most economically important fruit crop in the world, is extremely slow and inherently costly because of the long-term\\u000a nature of tree breeding and an unusual combination of reproductive characteristics. Aside from disease resistance, major commercial\\u000a traits inCitrusare improved fruit quality, higher yield and tolerance to environmental stresses, especially salinity.\\u000a \\u000a \\u000a \\u000a \\u000a Results  A normalized full length and 9 standard cDNA

Javier Terol; Ana Conesa; Jose M Colmenero; Manuel Cercos; Francisco Tadeo; Javier Agustí; Enriqueta Alós; Fernando Andres; Guillermo Soler; Javier Brumos; Domingo J Iglesias; Stefan Götz; Francisco Legaz; Xavier Argout; Brigitte Courtois; Patrick Ollitrault; Carole Dossat; Patrick Wincker; Raphael Morillon; Manuel Talon

2007-01-01

283

PhysicoChemical Characteristics of Citrus Seeds and Seed Oils from Pakistan  

Microsoft Academic Search

The physico-chemical characteristics of the seeds and seed oils of four citrus species, Mitha (Citrus limetta), Grapefruit (Citrus paradisi), Mussami (Citrus sinensis), and Kinnow (Citrus reticulata) were investigated. The hexane-extracted oil content of citrus seeds ranged from 27.0 to 36.5%. The protein, fiber and ash\\u000a contents were found to be 3.9–9.6%, 5.0–8.5%, and 4.6–5.6%, respectively. The extracted oils exhibited an

Farooq Anwar; Rehana Naseer; M. I. Bhanger; Samia Ashraf; Farah Naz Talpur; Felix Adekunle Aladedunye

2008-01-01

284

9. VIEW SHOWING ARIZONA CANAL WITH CITRUS ORCHARDS, FACING NORTH. ...  

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

9. VIEW SHOWING ARIZONA CANAL WITH CITRUS ORCHARDS, FACING NORTH. CAMELBACK MOUNTAIN IS IN THE BACKGROUND Photographer: unknown. No date - Arizona Canal, North of Salt River, Phoenix, Maricopa County, AZ

285

Enhancement of beta-carotene synthesis by citrus products.  

PubMed

beta-Ionone, a stimulatory compound in the microbiological production of beta-carotene by mated cultures of Blakeslea trispora, could be replaced with low-cost agricultural by-products (citrus oils, citrus pulp, or citrus molasses) with as good or better carotene yields. Peak yields (81 to 129 mg of carotene per g of dry solids) were achieved in 5 days. The various citrus products tested did not change the pigments produced; all trans-beta-carotene remained the pre-dominant pigment. The acid-hydrolyzed soybean meal and corn used in previous production media could be replaced with unhydrolyzed cottonseed embryo meal and corn in a medium that also contained a natural lipid, deodorized kerosene, nonionic detergent, and a precursor. PMID:14021337

CIEGLER, A; NELSON, G E; HALL, H H

1963-03-01

286

Waste Citrus Activated Sludge as a Poultry Feed Ingredient.  

National Technical Information Service (NTIS)

The report presents an evaluation of the potential of using waste activated sludge as a poultry feed supplement. The sludge used in this study was obtained from an activated sludge process treating concentrated citrus waste containing no sanitary wastewat...

B. L. Damron J. T. White R. H. Jones

1975-01-01

287

Evaluation of Citrus Rootstocks for Salinity Tolerance at Seedling Stage  

Microsoft Academic Search

Citrus rootstocks i.e. Jatti khatti (Citrus jambhiri), Jambheri khatti (C. jambhiri), Gada dehi (C. aurantium), Kharna khatta (C. karna), Cleopatra mandarin (C. reshni) and Yuma citrange (Poncirus trifoliata x C. sinensis) were evaluated for salinity tolerance by transplanting their six months old seedlings in an artificially salinized soil. Four salinity levels i.e. 2.0, 4.0, 6.0 and 8.0 dS m-1, were

MUHAMMAD AKBAR ANJUM; MUHAMMAD ABID; FARRUKH NAVEED

288

Production of tetraploid plants of non apomictic citrus genotypes  

Microsoft Academic Search

Ploidy manipulation in Citrus is a major issue of current breeding programs aiming to develop triploid seedless mandarins\\u000a to address consumer demands for seedless fruits. The most effective method to obtain triploid hybrids is to pollinate tetraploid\\u000a non apomictic cultivars with pollen of diploid varieties. Such non apomictic tetraploid lines are not found in the citrus\\u000a germplasm and need to

Pablo Aleza; José Juárez; Patrick Ollitrault; Luis Navarro

2009-01-01

289

Potential perchlorate exposure from Citrus sp. irrigated with contaminated water.  

PubMed

Citrus produced in the southwestern United States is often irrigated with perchlorate-contaminated water. This irrigation water includes Colorado River water which is contaminated with perchlorate from a manufacturing plant previously located near the Las Vegas Wash, and ground water from wells in Riverside and San Bernardino counties of California which are affected by a perchlorate plume associated with an aerospace facility once located near Redlands, California. Studies were conducted to evaluate the uptake and distribution of perchlorate in citrus irrigated with contaminated water, and estimate potential human exposure to perchlorate from the various citrus types including lemon (Citrus limon), grapefruit (Citrus paradise), and orange (Citrus sinensis) produced in the region. Perchlorate concentrations ranged from less than 2-9 microg/L for Colorado River water and from below detection to approximately 18 microg/L for water samples from wells used to irrigate citrus. Destructive sampling of lemon trees produced with Colorado River water show perchlorate concentrations larger in the leaves (1835 microg/kg dry weight (dw)) followed by the fruit (128 microg/kg dw). Mean perchlorate concentrations in roots, trunk, and branches were all less than 30 microg/kg dw. Fruit pulp analyzed in the survey show perchlorate concentrations ranged from below detection limit to 38 microg/kg fresh weight (fw), and were related to the perchlorate concentration of irrigation water. Mean hypothetical exposures (mug/person/day) of children and adults from lemons (0.005 and 0.009), grapefruit (0.03 and 0.24), and oranges (0.51 and 1.20) were estimated. These data show that potential perchlorate exposures from citrus in the southwestern United States are negligible relative to the reference dose recommended by the National Academy of Sciences. PMID:17723376

Sanchez, C A; Krieger, R I; Khandaker, N R; Valentin-Blasini, L; Blount, B C

2006-05-10

290

Scleroderris Canker on National Forests in Upper Michigan and Northern Wisconson.  

National Technical Information Service (NTIS)

During the past several years, many young red pine (Pinus resinosa Ait.) and jack pine (P. banksiana Lamb.) plantations in Upper Michigan and northern Wisconsin have suffered from poor growth and mortality. These symptoms of disease were first noted in re...

D. D. Skilling C. E. Cordell

1966-01-01

291

Citrus tristeza virus: Evolution of Complex and Varied Genotypic Groups  

PubMed Central

Amongst the Closteroviridae, Citrus tristeza virus (CTV) is almost unique in possessing a number of distinct and characterized strains, isolates of which produce a wide range of phenotype combinations among its different hosts. There is little understanding to connect genotypes to phenotypes, and to complicate matters more, these genotypes are found throughout the world as members of mixed populations within a single host plant. There is essentially no understanding of how combinations of genotypes affect symptom expression and disease severity. We know little about the evolution of the genotypes that have been characterized to date, little about the biological role of their diversity and particularly, about the effects of recombination. Additionally, genotype grouping has not been standardized. In this study we utilized an extensive array of CTV genomic information to classify the major genotypes, and to determine the major evolutionary processes that led to their formation and subsequent retention. Our analyses suggest that three major processes act on these genotypes: (1) ancestral diversification of the major CTV lineages, followed by (2) conservation and co-evolution of the major functional domains within, though not between CTV genotypes, and (3) extensive recombination between lineages that have given rise to new genotypes that have subsequently been retained within the global population. The effects of genotype diversity and host-interaction are discussed, as is a proposal for standardizing the classification of existing and novel CTV genotypes.

Harper, S. J.

2013-01-01

292

A transcriptionally active copia-like retroelement in Citrus limon.  

PubMed

The plant nuclear genome is largely composed of mobile DNA, which can rearrange genomes and other individual gene structure and also affect gene regulation through various promoted activities: transposition, insertion, excision, chromosome breakage, and ectopic recombination. Ty1-copia-like retrotransposon is a widespread class of transposable elements in the plant kingdom, representing a large part of the total DNA content. Here, a novel retrotransposon-like sequence was isolated and identified as the Ty1-copia-like reverse transcriptase domain (named here CLCoy1), based on the homology of known elements. Fluorescence in situ hybridization, revealed that CLCoy1 was mainly located in telomeric and sub-telomeric regions along the Citrus chromosomes. CLCoy1 composes 3.6% of the genome and, interestingly, while transposons are mostly specific to a species, this element was identified in other Citrus species such as Citrus aurantium, Fortunella margarita and Citrus paradisi, but undetected in Poncirus trifoliata. We also determined that wounding, salt and cell culture stress produced transcriptional activation of this novel retroelement in Citrus limon. The novel Ty1-copia-like element CLCoy1 may have played a major role in shaping genome structure and size during Citrus species evolution. PMID:19115051

De Felice, Bruna; Wilson, Robert R; Argenziano, Carolina; Kafantaris, Ioanis; Conicella, Clara

2009-01-01

293

Genetic Transformation of Citrus paradisi with Antisense and Untranslatable RNA-dependent RNA Polymerase Genes of Citrus tristeza closterovirus  

Microsoft Academic Search

Protein and RNA-mediated forms of pathogen-derived resistance (PDR) have been developed against many viruses in different plants. However, no resistance has been reported against Citrus tristeza virus (CTV), a closterovirus, in Citrus species transformed with coat protein genes or other sequences of CTV. The successful use of replication-associated genes in RNA-mediated resistance in other crops prompted the use of the

Richard F. LEE; Charles L. NIBLETT

294

Soilborne ascospores and pycnidiospores of Leptosphaeria maculans can contribute significantly to blackleg disease epidemiology in oilseed rape ( Brassica napus ) in Western Australia  

Microsoft Academic Search

Blackleg disease (Leptosphaeria maculans) causes severe yield losses in oilseed rape (Brassica napus) worldwide from the development of cankers in the crown of the plant and, in Western Australia, also from seedling death\\u000a following early infections. Although most aspects of the epidemiology of this disease are relatively well described, the role\\u000a of soilborne ascospores and pycnidiospores in the disease epidemic

Hua Li; K. Sivasithamparam; M. J. Barbetti

2007-01-01

295

Sequencing of diverse mandarin, pummelo and orange genomes reveals complex history of admixture during citrus domestication.  

PubMed

Cultivated citrus are selections from, or hybrids of, wild progenitor species whose identities and contributions to citrus domestication remain controversial. Here we sequence and compare citrus genomes-a high-quality reference haploid clementine genome and mandarin, pummelo, sweet-orange and sour-orange genomes-and show that cultivated types derive from two progenitor species. Although cultivated pummelos represent selections from one progenitor species, Citrus maxima, cultivated mandarins are introgressions of C. maxima into the ancestral mandarin species Citrus reticulata. The most widely cultivated citrus, sweet orange, is the offspring of previously admixed individuals, but sour orange is an F1 hybrid of pure C. maxima and C. reticulata parents, thus implying that wild mandarins were part of the early breeding germplasm. A Chinese wild 'mandarin' diverges substantially from C. reticulata, thus suggesting the possibility of other unrecognized wild citrus species. Understanding citrus phylogeny through genome analysis clarifies taxonomic relationships and facilitates sequence-directed genetic improvement. PMID:24908277

Wu, G Albert; Prochnik, Simon; Jenkins, Jerry; Salse, Jerome; Hellsten, Uffe; Murat, Florent; Perrier, Xavier; Ruiz, Manuel; Scalabrin, Simone; Terol, Javier; Takita, Marco Aurélio; Labadie, Karine; Poulain, Julie; Couloux, Arnaud; Jabbari, Kamel; Cattonaro, Federica; Del Fabbro, Cristian; Pinosio, Sara; Zuccolo, Andrea; Chapman, Jarrod; Grimwood, Jane; Tadeo, Francisco R; Estornell, Leandro H; Muñoz-Sanz, Juan V; Ibanez, Victoria; Herrero-Ortega, Amparo; Aleza, Pablo; Pérez-Pérez, Julián; Ramón, Daniel; Brunel, Dominique; Luro, François; Chen, Chunxian; Farmerie, William G; Desany, Brian; Kodira, Chinnappa; Mohiuddin, Mohammed; Harkins, Tim; Fredrikson, Karin; Burns, Paul; Lomsadze, Alexandre; Borodovsky, Mark; Reforgiato, Giuseppe; Freitas-Astúa, Juliana; Quetier, Francis; Navarro, Luis; Roose, Mikeal; Wincker, Patrick; Schmutz, Jeremy; Morgante, Michele; Machado, Marcos Antonio; Talon, Manuel; Jaillon, Olivier; Ollitrault, Patrick; Gmitter, Frederick; Rokhsar, Daniel

2014-07-01

296

The antiallergic mechanisms of Citrus sunki and bamboo salt (K-ALL) in an allergic rhinitis model.  

PubMed

The antiallergic effects of traditional medicines have long been studied. Traditional Korean medicine, Citrus sunki and bamboo salt, has been used for the treatment of allergic diseases in Korea. K-ALL, composed of Citrus sunki and bamboo salt, is a newly prepared prescription for allergic patients. To develop the new antiallergic agent, we examined the effects of K-ALL through in vivo and in vitro models. K-ALL and naringin (an active compound of K-ALL) significantly inhibited histamine release from rat peritoneal mast cells. This inhibitory effect of K-ALL on histamine release was higher than effects from other known histamine inhibitors such as bamboo salt, Citrus sunki or disodium cromoglycate. K-ALL significantly inhibited systemic anaphylactic shock induced by the compound 48/80 and passive cutaneous anaphylaxis induced by the IgE. K-ALL also inhibited production and mRNA expression of inflammatory cytokines induced by phorbol 12-myristate 13-acetate and the calcium ionophore A23187 on HMC-1 cells (a human mast cell line). In the ovalbumin-induced allergic rhinitis animal model, rub scores, histamine, IgE, inflammatory cytokines and inflammatory cell counts were all reduced by the oral or nasal administration of K-ALL (pre and posttreatment). These results indicate the great potential of K-ALL as an active immune modulator for the treatment of mast cell-mediated allergic diseases. PMID:24131540

Oh, Hyun-A; Kim, Myong-Jo; Shin, Tae-Yong; Kim, Hyung-Min; Jeong, Hyun-Ja

2014-01-01

297

Convenient Detection of the Citrus Greening (Huanglongbing) Bacterium 'Candidatus Liberibacter asiaticus' by Direct PCR from the Midrib Extract  

PubMed Central

A phloem-limited bacterium, ‘Candidatus Liberibacter asiaticus’ (Las) is a major pathogen of citrus greening (huanglongbing), one of the most destructive citrus diseases worldwide. The rapid identification and culling of infected trees and budwoods in quarantine are the most important control measures. DNA amplification including conventional polymerase chain reaction (PCR) has commonly been used for rapid detection and identification. However, long and laborious procedures for DNA extraction have greatly reduced the applicability of this method. In this study, we found that the Las bacterial cells in the midribs of infected leaves were extracted rapidly and easily by pulverization and centrifugation with mini homogenization tubes. We also found that the Las bacterial cells in the midrib extract were suitable for highly sensitive direct PCR. The performance of direct PCR using this extraction method was not inferior to that of conventional PCR. Thus, the direct PCR method described herein is characterized by its simplicity, sensitivity, and robustness, and is applicable to quarantine testing.

Fujikawa, Takashi; Miyata, Shin-Ichi; Iwanami, Toru

2013-01-01

298

East Adriatic—a reservoir region of severe Citrus tristeza virus strains  

Microsoft Academic Search

Citrus tristeza virus (CTV) represents one of the major threats to citrus production worldwide. In the East Adriatic region, CTV symptoms are mostly\\u000a absent due to traditional citrus grafting on trifoliate orange (Poncirus trifoliata), a CTV-tolerant rootstock. Therefore, the virus has been continuously spreading by the propagation of infected material.\\u000a The genetic variability of CTV was studied on nineteen citrus

Silvija Cerni; Dijana Skoric; Jelena Ruscic; Mladen Krajacic; Tatjana Papic; Khaled Djelouah; Gustavo Nolasco

2009-01-01

299

Involvement of rooting factors and free IAA in the rootability of citrus species stem cuttings  

Microsoft Academic Search

Sagee, O., Raviv, M., Medina, Sh., Becker, D. and Cosse, A., 1992. Involvement of rooting factors and free IAA in the rootability of citrus species stem cuttings. Scientia Hortic., 51: 187-195. Two-year-old trees of cultivar 'Rangpur' lime (Citrus fimonia Osb. ) and of cultivar 'Oroblanco', a triploid pummelo-grapefruit hybrid (Citrus grandis Osb. X Citrus paradisi Macf.), which had not reached

O. Sagee; M. Raviv; D. Beckeff; A. Cosse

1992-01-01

300

Beneficial roles of arbuscular mycorrhizas in citrus seedlings at temperature stress  

Microsoft Academic Search

Citrus, a cold-sensitive plant, often suffers from low temperature, which seriously affects citrus productivity. The objective of the study was to elevate the roles of an arbuscular mycorrhizal fungus, Glomus mosseae, in growth, photosynthesis, root morphology and nutrient uptake of citrus (Citrus tangerine) seedlings under temperature stress conditions. Three-month-old seedlings with or without G. mosseae were grown for 55 days

Qiang-Sheng Wu; Ying-Ning Zou

2010-01-01

301

Somatic hybridization in citrus: An effective tool to facilitate variety improvement  

Microsoft Academic Search

Summary  Citrus somatic hybridization and cybridization via protoplast fusion has become an integral part of citrus variety improvement programs worldwide. Citrus somatic hybrid plants\\u000a have been regenerated from more than 200 parental combinations, and several cybrid combinations have also been produced. Applications\\u000a of somatic hybridization to citrus scion improvement include the production of quality tetraploid breeding parents that can\\u000a be used

J. W. Grosser; P. Ollitrault; O. Olivares-Fuster

2000-01-01

302

Deep sequencing discovery of novel and conserved microRNAs in trifoliate orange (Citrus trifoliata)  

PubMed Central

Background MicroRNAs (miRNAs) play a critical role in post-transcriptional gene regulation and have been shown to control many genes involved in various biological and metabolic processes. There have been extensive studies to discover miRNAs and analyze their functions in model plant species, such as Arabidopsis and rice. Deep sequencing technologies have facilitated identification of species-specific or lowly expressed as well as conserved or highly expressed miRNAs in plants. Results In this research, we used Solexa sequencing to discover new microRNAs in trifoliate orange (Citrus trifoliata) which is an important rootstock of citrus. A total of 13,106,753 reads representing 4,876,395 distinct sequences were obtained from a short RNA library generated from small RNA extracted from C. trifoliata flower and fruit tissues. Based on sequence similarity and hairpin structure prediction, we found that 156,639 reads representing 63 sequences from 42 highly conserved miRNA families, have perfect matches to known miRNAs. We also identified 10 novel miRNA candidates whose precursors were all potentially generated from citrus ESTs. In addition, five miRNA* sequences were also sequenced. These sequences had not been earlier described in other plant species and accumulation of the 10 novel miRNAs were confirmed by qRT-PCR analysis. Potential target genes were predicted for most conserved and novel miRNAs. Moreover, four target genes including one encoding IRX12 copper ion binding/oxidoreductase and three genes encoding NB-LRR disease resistance protein have been experimentally verified by detection of the miRNA-mediated mRNA cleavage in C. trifoliata. Conclusion Deep sequencing of short RNAs from C. trifoliata flowers and fruits identified 10 new potential miRNAs and 42 highly conserved miRNA families, indicating that specific miRNAs exist in C. trifoliata. These results show that regulatory miRNAs exist in agronomically important trifoliate orange and may play an important role in citrus growth, development, and response to disease.

2010-01-01

303

Citrus Tree Abiotic and Biotic Stress and Implication of Simulation and Modeling Tools in Tree Management  

Microsoft Academic Search

Plant abiotic and biotic stress is related to unfavorable and environmental constraints. As a warm climate tree fruit crop, citrus (Citrus sinensis (L.) Osb.) is adapted to a wide variety of soil types and growth conditions. However, when waterlogging, soil acidity and root weevil infestation occur simultaneously, citrus roots can be injured from anaerobic disturbance, oxygen deprivation and root injury,

Hong Li

304

Allotetraploid hybrids between citrus and seven related genera produced by somatic hybridization  

Microsoft Academic Search

We have developed an efficient protoplast-fusion method to produce somatic hybrid allopolyploid plants that combine Citrus with seven related genera, including four that are sexually incompatible. In this paper we report the creation of 18 new allotetraploid hybrids of Citrus, including ten among sexually incompatible related genera, that may have direct cultivar potential as improved citrus rootstocks. All hybrids were

J. W. Grosser; F. A. A. Mourao-Fo; F. G. Gmitter Jr; E. S. Louzada; J. Jiang; K. Baergen; A. Quiros; C. Cabasson; J. L. Schell; J. L. Chandler

1996-01-01

305

Regeneration and molecular characterization of intergeneric somatic hybrids between Citrus reticulata and Poncirus trifoliata  

Microsoft Academic Search

Citrus exocortis viroid (CEV) is widespread in citrus production areas where trifoliate orange [Poncirus trifoliata (L.) Raf.] is used as rootstock. Citrus reticulata Blanco cv. Red tangerine, a different rootstock, is tolerant to CEV. Embryogenic protoplasts of C. reticulata cv. Red tangerine were electrically fused with mesophyll protoplasts from P. trifoliata, and five embryoids were regenerated after 40 days of

W. W. Guo; Y. J. Cheng; X. X. Deng

2002-01-01

306

Some physiological and morphological characteristics of citrus plants for drought resistance  

Microsoft Academic Search

Tolerance and avoidance mechanisms to drought stress were studied in 6-month-old plants of Newhall orange (Citrus sinensis (L.) Osbeck) and Ellendale tangor (orange × mandarin hybrid) (Citrus sinensis (L) Osbeck × Citrus reticulata Blanco) during a drought\\/rewatering cycle under controlled conditions. Drought stress did not promote osmotic adjustment, while elastic adjustment (tissue elasticity increase) was noted in stressed orange and

Robert Savé; Carme Biel; Rafael Domingo; M. Carmen Ruiz-Sánchez; Arturo Torrecillas

1995-01-01

307

ACCEPTABILITY AND DIGESTIBILITY OF DRIED CITRUS PULP BY HORSES 1'2  

Microsoft Academic Search

Summary Two acceptability trials with eight mature horses were used to compare coarse grain con- centrates containing 0 or 30% dried citrus pulp in place of oats. All of the horses consumed the control concentrate readily and two of the eight horses consumed the concentrate contain- ing dried citrus pulp. Six horses refused the citrus pulp concentrate, consuming only 8.6%

E. A. Ott; J. P. Feaster; Sandi Lieb

2010-01-01

308

Factors affecting captures of male citrus leafminer, Phyllocnistis citrella Stainton, in pheromone-baited traps  

Microsoft Academic Search

The citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillar- iidae), is an important world-wide pest of citrus. Larval mining within leaf flush impacts yield and predisposes trees to infection by citrus can- ker, Xanthomonas axonopodis pv. citri. The present series of studies sought to identify factors affecting male P. citrella catch in pheromone-baited traps with the intent of developing effective monitoring.

L. L. Stelinski; M. E. Rogers

2008-01-01

309

‘Swingle’ citrumelo propagation by cuttings for citrus nursery tree production or inarching  

Microsoft Academic Search

‘Swingle’ citrumelo [Citrus paradisi MacFaden×Poncirus trifoliata (L.) Raf.] has been extensively used as a rootstock in several citrus growing regions of the World, including Southern Brazil where ‘Rangpur’ lime (Citrus limonia Osbeck) is still the predominant variety despite being affected by several important pathogens. In this case, ‘Swingle’ citrumelo is used to produce nursery trees to establish new orchards or

Francisco de Assis Alves Mourão Filho; Eduardo Augusto Girardi; Hilton Thadeu Zarate do Couto

2009-01-01

310

Citrus Flavonoids in Fruit and Traditional Chinese Medicinal Food Ingredients in China  

Microsoft Academic Search

.  Flavonoids-enriched tissues of citrus such as peel, immature fruit and flower are consumed as culinary seasonings, tea ingredients in China for centuries. This HPLC quantitative study on the five citrus flavonoids, naringin, hesperidin, neohesperidin, sinensetin and nobiletin on a wide range of Chinese citrus fruits and several Traditional Chinese Medicinal food ingredients in East China, revealed a great diversity in

Yanhua Lu; Chongwei Zhang; Peter Bucheli; Dongzhi Wei

2006-01-01

311

Microbial parasites associated with Tylenchulus semipenetrans in citrus orchards of Catalonia, Spain  

Microsoft Academic Search

Citrus orchards in Catalonia, Spain were surveyed to identify microbial parasites of Tylenchulus semipenetrans, and their distribution and density. Of 62 orchards, 48 were positively infested with the citrus nematode. Fungal strains were isolated from single eggs, females or second-stage juveniles of the citrus nematode in 69% of the infested orchards. The fungi identified in order of occurrence were Paecilomyces

J. Gené; S. Verdejo-Lucas; A. M. Stchigel; F. J. Sorribas; J. Guarro

2005-01-01

312

Citrus essential oils and four enantiomeric pinenes against Culex pipiens (Diptera: Culicidae)  

Microsoft Academic Search

The aim of this study was to evaluate the toxicity of pinenes (entantiomers of ?- and ?-) and essential oils from Greek plants of the Rutaceae family against the mosquito larvae of Culex pipiens (Diptera: Culicidae). Essential oils were isolated by hydrodistillation from fruit peel of orange (Citrus sinensis L.), lemon (Citrus limon L.), and bitter orange (Citrus aurantium L.).

Antonios Michaelakis; Dimitrios Papachristos; Athanasios Kimbaris; George Koliopoulos; Athanasios Giatropoulos; Moschos G. Polissiou

2009-01-01

313

Climate and economic competitiveness: Florida freezes and the global citrus processing industry  

Microsoft Academic Search

Casual observers of the impacts associated with four recent freezes in Florida's citrus producing areas might be inclined to agree with an assessment by Miami Herald reporters that these freezes had caused the ‘king of citrus’ to be toppled from its throne, enabling Brazil to take its place. Research on the citrus industry, however, reveals that the impacts of these

Kathleen A. Miller; Michael H. Glantz

1988-01-01

314

Functional characterization of AP3, SOC1 and WUS homologues from citrus (Citrus sinensis).  

PubMed

Flowering and flower formation are defining features of angiosperms and the control of these developmental processes involves a common repertoire of genes which are shared among different species of flowering plants. These genes were first identified using various homeotic and flowering time mutants of Arabidopsis and snapdragon, and homologous genes have subsequently been isolated from a wide range of different plant species based on the conservation of protein sequence and function. Using degenerate reverse-transcriptase polymerase chain reaction, we have isolated one APETALA3-like (CitMADS8) and two SOC1 (SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1)-like (CsSL1 and CsSL2) homologues from sweet orange (Citrus sinensis L.). Although the translated amino acid sequence of CitMADS8 shares many similarities with other higher plant APETALA3 proteins, CitMADS8 fails to complement the floral organ identity defects of the Arabidopsis ap3-3 mutant. By contrast, the two citrus SOC1-like genes, particularly CsSL1, are able to shorten the time taken to flower in the Arabidopsis wild-type ecotypes Columbia and C24, and functionally complement the late flowering phenotype of the soc1 mutant, essentially performing the endogenous function of Arabidopsis SOC1. Once flowering has commenced, interactions between specific flowering genes and a gene required for meristem maintenance, WUSCHEL, ensure that the Arabidopsis flower is a determinate structure with four whorls. We have isolated a citrus WUSCHEL homologue (CsWUS) that is capable of restoring most of the meristem function to the shoots and flowers of the Arabidopsis wus-1 mutant, implying that CsWUS is the functional equivalent of Arabidopsis WUSCHEL. PMID:18251886

Tan, Fui-Ching; Swain, Stephen M

2007-11-01

315

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

PubMed

Asian citrus psyllid (Diaphorina citri) transmits the causal agent of Huanglongbing, a devastating disease of citrus trees. In this study we measured behavioral responses of D. citri to combinations of visual, olfactory, and gustatory stimuli in test arenas. Stimuli were presented to the psyllids in droplets or lines of an emulsified wax formulation in two different arena types in no-choice tests. First, when placed on a colored ring situated halfway between the center and perimeter of a petri dish, D. citri spent more time on yellow versus gray rings; however, this response disappeared when either gray or yellow wax droplets were applied. When the psyllids were presented with droplets scented with terpenes, the response to both scent and color was increased. The addition of a dilute (?0.1 M) sucrose solution to the wax droplets increased the magnitude of D. citri responses. Next, groups of D. citri were placed on plastic laboratory film covering a sucrose solution, to mimic a leaf surface. Test stimuli were presented via two 'midribs' made from lines of emulsified wax formulation. Probing levels were measured as a function of color saturation and scent composition, and concentration. The test scents were based on qualitatively major volatiles emitted by Murraya paniculata (L.) Jack, Citrus aurantifolia (Christm.) Swingle, and C. sinensis (L.) Osbeck. The highest probing response was observed on the middle concentration (20-?l scent/10 ml wax formulation) of the C. aurantifolia-scented wax lines. Results indicate that there are interactive effects between the different sensory modalities in directing host-plant assessment behavior. PMID:22217766

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

2011-12-01

316

Interaction of Simulated Acid Rain with Ozone on Freeze Resistance, Growth, and Mineral Nutrition in Citrus and Avocado 1  

Microsoft Academic Search

The combined effects of O3 and acid rain on freeze resistance, growth, and mineral nutrition were studied using broadleaf-evergreen citrus and avocado trees. Using a factorial design, 'Ruby red' grapefruit (Citrus paradisi L.) trees on either Volkamer lemon (Citrus volkameriana Ten. & Pasq.) or sour orange (Citrus aurantium L.) rootstocks and 'Pancho' avocado trees (Persea americana Mill.) on 'Waldin' rootstock

David M. Eissenstat; James P. Syvertsen; Thomas J. Dean; Jon D. Johnson; George Yelenosky

1991-01-01

317

????????????????????????????? ??????????????????????????? ????? ???????????????????? ??????????????? Xanthomonas axonopodis pv.citri Efficacy of Crude Extract form Beleric Myrobalan, Chebulic Myrobalan and Nut Gall Fruit on the Symptom Development of Kaffir lime Canker Caused by Xanthomonas axonopodis pv.citri  

Microsoft Academic Search

The efficacy of crude extract from beleric myrobalan, chebulic myrobalan and nut gall fruit on the symptom development of kaffir lime canker caused by Xanthomonas axonopodis pv.citri was studied. The crude extract of plants were extracted by 95% ethyl alcohol and evaporated the solvent by Rotary vacuum evaporator.The bacterial suspension was inoculated on 15 month kaffir lime leaves in the

Sasitorn Vudhivanich

318

The impact of climate change on disease constraints on production of oilseed rape  

Microsoft Academic Search

Weather data generated for different parts of the UK under five climate change scenarios (baseline, 2020s low CO2 emissions, 2020s high emissions, 2050s low emissions, 2050s high emissions) were inputted into weather-based models for predicting\\u000a oilseed rape yields and yield losses from the two most important diseases, phoma stem canker and light leaf spot. An economic\\u000a analysis of the predictions

Neal Evans; Michael H. Butterworth; Andreas Baierl; Mikhail A. Semenov; Jon S. West; Andrew Barnes; Dominic Moran; Bruce D. L. Fitt

2010-01-01

319

Resistance of citrus genotypes to Phyllocnitis citrella Stainton (Lepidoptera: Gracillariidae).  

PubMed

The development and reproduction of the citrus leafminer (CLM), Phyllocnistis citrella Stainton, were evaluated in six citrus genotypes in order to identify genotypes with resistance traits that could be applied in a program for the development of citrus varieties resistant to the citrus leafminer. Tests were conducted under controlled laboratory conditions (25 ± 1ºC, 70 ± 10% RH, and 14h photophase). Seedlings of each genotype tested were infested with eggs obtained from a stock colony of CLM maintained on 'Cravo' lemon (Citrus limonia L. Osbeck), and the duration and survival of the eggs, larval and pupal stages, pupal size and weight, fecundity and longevity of adults, and sex ratio were evaluated. No influence was observed on the duration and survival of eggs, larvae and pupae of P. citrella. However, pupae obtained in the hybrid C x R(4) were significantly smaller and lighter than pupae from the remaining treatments. Adult females from the hybrids C x R(4) and C x R(315) were the least fecund. However, the lowest value for the corrected reproductive potential (CRP) was recorded in the hybrid C x R(315), suggesting that this genotype is the least favorable for the development and reproduction of CLM. On the other hand, the highest CRP value obtained in the 'Rugoso' lemon confirms the susceptibility of this genotype, indicating it as the most suitable for CLM. PMID:21952967

Santos, M S; Vendramim, J D; Lourenção, A L; Pitta, R M; Martins, E S

2011-01-01

320

Mapping, genetic effects, and epistatic interaction of two bacterial canker resistance QTLs from Lycopersicon hirsutum.  

PubMed

Two quantitative trait loci (QTL) from Lycopersicon hirsutum, Rcm 2.0 and Rcm 5.1, control resistance to Clavibacter michiganensis subsp. michiganensis ( Cmm). To precisely map both loci, we applied interval mapping techniques to 1,056 individuals in three populations exhibiting F(2) segregation. Based on a 1-LOD confidence interval, Rcm 2.0 mapped to a 14.9-cM interval on chromosome 2 and accounted for 25.7-34.0% of the phenotypic variation in disease severity. Rcm 5.1 mapped to a 4.3-cM interval on chromosome 5 and accounted for 25.8-27.9% of the phenotypic variation. Progeny testing of recombinant plants narrowed the QTL location for Rcm 2.0 to a 4.4-cM interval between TG537-TG091 and to a 2.2-cM interval between CT202-TG358 for Rcm 5.1. A population of 750 individuals exhibiting F(2) segregation was used to detect epistasis between both loci using ANOVA and orthogonal contrasts ( P=0.027), suggesting that resistance was determined by additive gene action and an additive-by-additive epistatic interaction. A partial diallel mating design was used to confirm epistasis, advance superior genotypes, randomize genetic backgrounds, and create recombination opportunities. This crossing scheme created a more balanced population ( n=112) containing the nine F(2) genotypic classes. Parents in the diallel were selected from the previous population based on resistance, genotype at the Rcm 2.0 and Rcm 5.1 loci, and horticultural traits. A replicated trial using the diallel population confirmed additive-by-additive epistasis ( P<0.0001). These results validate the gene action, intra -locus interaction, and map position of two loci controlling resistance to Cmm. PMID:15067391

Coaker, G L; Francis, D M

2004-04-01

321

Volatile constituents of redblush grapefruit (Citrus paradisi) and pummelo (Citrus grandis) peel essential oils from Kenya.  

PubMed

The volatile constituents of cold-pressed peel essential oils of redblush grapefruit (Citrus paradisi Macfadyen forma Redblush) and pummelo (Citrus grandis Osbeck) from the same locality in Kenya were determined by GC and GC-MS. A total of 67 and 52 compounds, amounting to 97.9 and 98.8% of the two oils, respectively, were identified. Monoterpene hydrocarbons constituted 93.3 and 97.5% in the oils, respectively, with limonene (91.1 and 94.8%), alpha-terpinene (1.3 and 1.8%), and alpha-pinene (0.5%) as the main compounds. Sesquiterpene hydrocarbons constituted 0.4% in each oil. The notable compounds were beta-caryophyllene, alpha-cubebene, and (E,E)-alpha-farnesene. Oxygenated compounds constituted 4.2 and 2.0% of the redblush grapefruit and pummelo oils, respectively, out of which carbonyl compounds (2.0 and 1.3%), alcohols (1.4 and 0.3%), and esters (0.7 and 0.4%) were the major groups. Heptyl acetate, octanal, decanal, citronellal, and (Z)-carvone were the main constituents (0.1-0.5%). Perillene, (E)-carveol, and perillyl acetate occurred in the redblush grapefruit but were absent from the pummelo oil. Nootkatone, alpha- and beta-sinensal, methyl-N-methylanthranilate, and (Z,E)-farnesol were prominent in both oils. PMID:16332132

Njoroge, Simon Muhoho; Koaze, Hiroshi; Karanja, Paul Nyota; Sawamura, Masayoshi

2005-12-14

322

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

PubMed

?-Aminobutyric acid (BABA) is known to induce resistance to microbial pathogens, nematodes and insects in several host plant/pest systems. The present study was undertaken to determine whether a similar effect of BABA occurred against the Asian citrus psyllid, Diaphorina citri Kuwayama, in citrus. A 25 mM drench application of BABA significantly reduced the number of eggs/plant as compared with a water control, whereas 200 and 100 mM applications of BABA reduced the numbers of nymphs/plant and adults/plants, respectively. A 5 mM foliar application of BABA significantly reduced the number of adults but not eggs or nymphs when compared with a water control treatment. In addition, leaf-dip bioassays using various concentrations (25–500 mM) of BABA indicated no direct toxic effect on 2nd and 5th instar nymphs or adult D. citri. BABA-treated plants were characterized by significantly lower levels of iron, magnesium, phosphorus, sodium, sulfur and zinc as compared with control plants. The expression level of the PR-2 gene (?-1,3-glucanase) in BABA-treated plants that were also damaged by D. citri adult feeding was significantly higher than in plants exposed to BABA, D. citri feeding alone or control plants. Our results indicate the potential for using BABA as a systemic acquired resistance management tool for D. citri. PMID:23590847

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

2013-10-01

323

Grouping and comparison of Indian citrus tristeza virus isolates based on coat protein gene sequences and restriction analysis patterns.  

PubMed

Citrus tristeza virus (CTV) is an aphid-transmitted closterovirus, which causes one of the most important citrus diseases worldwide. Isolates of CTV differ widely in their biological properties. CTV-infected samples were collected from four locations in India: Bangalore (CTV-B), Delhi (CTV-D), Nagpur (CTV-N), and Pune (CTV-P), and were maintained by grafting into Kagzi lime ( Citrus aurantifolia (Christm. Swing.). All isolates produced typical vein clearing and flecking symptoms 6-8 weeks after grafting. In addition, CTV-B and CTV-P isolates produced stem-pitting symptoms after 8-10 months. The CTV coat protein gene (CPG) was amplified by RT-PCR using CPG specific primers, yielding an amplicon of 672 bp for all the isolates. Sequence analysis of the CPG amplicon of all the four Indian isolates showed 93-94% nucleotide sequence homology to the Californian CTV severe stem pitting isolate SY568 and 92-93% homology to the Japanese seedling yellows isolate NUagA and Israeli VT p346 isolates. In phylogenetic tree analysis, Indian CTV isolates appeared far different from other isolates as they formed a separate branch. Comparison among the Indian isolates was carried out by restriction analysis and restriction fragment length polymorphism (RFLP). Specific primers to various genome segments of well-characterized CTV isolates were used to further classify the Indian CTV isolates. PMID:12664295

Roy, A; Ramachandran, P; Brlansky, R H

2003-04-01

324

Antagonists of Plant-parasitic Nematodes in Florida Citrus.  

PubMed

In a survey of antagonists of nematodes in 27 citrus groves, each with a history of Tylenchulus semipenetrans infestation, and 17 noncitrus habitats in Florida, approximately 24 species of microbial antagonists capable of attacking vermiform stages of Radopholus citrophilus were recovered. Eleven of these microbes and a species of Pasteuria also were observed attacking vermiform stages of T. semipenetrans. Verticillium chlamydosporium, Paecilomyces lilacinus, P. marquandii, Streptomyces sp., Arthrobotrys oligospora, and Dactylella ellipsospora were found infecting T. semipenetrans egg masses. Two species of nematophagous amoebae, five species of predatory nematodes, and 29 species of nematophagous arthropods also were detected. Nematode-trapping fungi and nematophagous arthropods were common inhabitants of citrus groves with a history of citrus nematode infestation; however, obligate parasites of nematodes were rare. PMID:19287759

Walter, D E; Kaplan, D T

1990-10-01

325

Antagonists of Plant-parasitic Nematodes in Florida Citrus  

PubMed Central

In a survey of antagonists of nematodes in 27 citrus groves, each with a history of Tylenchulus semipenetrans infestation, and 17 noncitrus habitats in Florida, approximately 24 species of microbial antagonists capable of attacking vermiform stages of Radopholus citrophilus were recovered. Eleven of these microbes and a species of Pasteuria also were observed attacking vermiform stages of T. semipenetrans. Verticillium chlamydosporium, Paecilomyces lilacinus, P. marquandii, Streptomyces sp., Arthrobotrys oligospora, and Dactylella ellipsospora were found infecting T. semipenetrans egg masses. Two species of nematophagous amoebae, five species of predatory nematodes, and 29 species of nematophagous arthropods also were detected. Nematode-trapping fungi and nematophagous arthropods were common inhabitants of citrus groves with a history of citrus nematode infestation; however, obligate parasites of nematodes were rare.

Walter, David Evans; Kaplan, David T.

1990-01-01

326

[Genetic variation of Citrus calli revealed by the ploidy analyser].  

PubMed

The cell DNA content of forty-eight Citrus calli of different genotype were measured by using the Ploidy Analyser. The results showed that 93.8% out of forty-eight Citrus calli had double DNA content except that Ruby. Weizhang and Kinnow had little varied cells and did not show second peak. Moreover, Pineapple, Meiwa kumquat, Changsha, Russ navel, Guoqing No. 4 and Carter had DNA varied cells including triploids and aneuploids based on the DPAC software analyse. Among the forty-eight Citrus calli, Pineapple had the highest of the DNA varied cells, which was up to 18.57%, Anliucheng had the lowest, 4.07%. There existed significant difference in the variation among genotypes by Duncan Analyse. At the same subcultured medium and at the same subcultured period, the effect of cultural duration on the variation of calli was not significant. PMID:12776606

Zhang, Jun-E; Liu, Ji-Hong; Deng, Xiu-Xin

2003-02-01

327

Natural bioactive compounds of Citrus limon for food and health.  

PubMed

Citrus genus is the most important fruit tree crop in the world and lemon is the third most important Citrus species. Several studies highlighted lemon as an important health-promoting fruit rich in phenolic compounds as well as vitamins, minerals, dietary fiber, essential oils and carotenoids. Lemon fruit has a strong commercial value for the fresh products market and food industry. Moreover, lemon productive networks generate high amounts of wastes and by-products that constitute an important source of bioactive compounds with potential for animal feed, manufactured foods, and health care. This review focuses on the phytochemistry and the analytical aspects of lemon compounds as well as on the importance for food industry and the relevance of Citrus limon for nutrition and health, bringing an overview of what is published on the bioactive compounds of this fruit. PMID:19748198

González-Molina, E; Domínguez-Perles, R; Moreno, D A; García-Viguera, C

2010-01-20

328

Inhibition of citrus fungal pathogens by using lactic acid bacteria.  

PubMed

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

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

2010-08-01

329

Freezing Tolerance of Citrus, Spinach, and Petunia Leaf Tissue 1  

PubMed Central

Seasonal variations in freezing tolerance, water content, water and osmotic potential, and levels of soluble sugars of leaves of field-grown Valencia orange (Citrus sinensis) trees were studied to determine the ability of citrus trees to cold acclimate under natural conditions. Controlled environmental studies of young potted citrus trees, spinach (Spinacia pleracea), and petunia (Petunia hybrids) were carried out to study the water relations during cold acclimation under less variable conditions. During the coolest weeks of the winter, leaf water content and osmotic potential of field-grown trees decreased about 20 to 25%, while soluble sugars increased by 100%. At the same time, freezing tolerance increased from lethal temperature for 50% (LT50) of ?2.8 to ?3.8°C. In contrast, citrus leaves cold acclimated at a constant 10°C in growth chambers were freezing tolerant to about ?6°C. The calculated freezing induced cellular dehydration at the LT50 remained relatively constant for field-grown leaves throughout the year, but increased for leaves of plants cold acclimated at 10°C in a controlled environment. Spinach leaves cold acclimated at 5°C tolerated increased cellular dehydration compared to nonacclimated leaves. Cold acclimated petunia leaves increased in freezing tolerance by decreasing osmotic potential, but had no capacity to change cellular dehydration sensitivity. The result suggest that two cold acclimation mechanisms are involved in both citrus and spinach leaves and only one in petunia leaves. The common mechanism in all three species tested was a minor increase in tolerance (about ?1°C) resulting from low temperature induced osmotic adjustment, and the second in citrus and spinach was a noncolligative mechanism that increased the cellular resistance to freeze hydration.

Yelenosky, George; Guy, Charles L.

1989-01-01

330

Citrus consumption and cancer incidence: the Ohsaki cohort study.  

PubMed

Basic research and case-control studies have suggested that citrus consumption may protect against cancer. However, the protective effect has been observed from few prospective studies. This study investigated the association of citrus consumption with cancer incidence among 42,470 Japanese adults in the Ohsaki National Health Insurance Cohort, which covered an age range of 40-79 years, and was followed up from 1995 to 2003 for all-cancer and individual cancer incidence. Citrus consumption was assessed using a self-administered questionnaire. The Cox proportional hazard model was applied to estimate relative risks (RRs) and 95% CIs. During the 323,204 person-years of follow-up, 3,398 cases were identified totally. Citrus consumption, especially daily consumption, was correlated with reduced all-cancer incidence, the RRs were 0.89 (95% CI = 0.80-0.98) for total participants, 0.86 (0.76-0.98) for males and 0.93 (0.79-1.09) for females, as well as multiple cancers at individual sites, especially pancreatic (RR = 0.62, 95% CI = 0.38-1.00) and prostate cancer (RR = 0.63, 95% CI = 0.41-0.97). Joint effect analysis showed a reduced risk of overall cancer existed only for subjects who consumed >or=1 cup green tea/day (RR = 0.83, 95% CI = 0.73-0.93) as well as for males (RR = 0.83, 95% CI = 0.71-0.97) or females (RR = 0.82, 95% CI = 0.68-0.99). These findings suggest that citrus consumption is associated with reduced all-cancer incidence, especially for subjects having simultaneously high green tea consumption. Further work on the specific citrus constituents is warranted, and clinical trials are ultimately necessary to confirm the protective effect. PMID:20104526

Li, Wen-Qing; Kuriyama, Shinichi; Li, Qiang; Nagai, Masato; Hozawa, Atsushi; Nishino, Yoshikazu; Tsuji, Ichiro

2010-10-15

331

Weedy hosts and prevalence of potential leafhopper vectors (Hemiptera: Cicadellidae) of a phytoplasma (16SrIX group) associated with Huanglongbing symptoms in citrus groves.  

PubMed

Huanglongbing (HLB) is a severe citrus (Citrus spp.) disease associated with the bacteria genus Candidatus Liberibacter, detected in Brazil in 2004. Another bacterium was found in association with HLB symptoms and characterized as a phytoplasma belonging to the 16SrIX group. The objectives of this study were to identify potential leafhopper vectors of the HLB-associated phytoplasma and their host plants. Leafhoppers were sampled every other week for 12 mo with sticky yellow cards placed at two heights (0.3 and 1.5 m) in the citrus tree canopy and by using a sweep net in the ground vegetation of two sweet orange, Citrus sinensis (L.) Osbeck, groves infected by the HLB-phytoplasma in São Paulo state. Faunistic analyses indicated one Agalliinae (Agallia albidula Uhler) and three Deltocephalinae [Balclutha hebe (Kirkaldy), Planicephalus flavicosta (Stål), and Scaphytopius (Convelinus) marginelineatus (Stål)] species, as the most abundant and frequent leafhoppers (Hemiptera: Cicadellidae). Visual observations indicated an association of leafhopper species with some weeds and the influence of weed species composition on leafhopper abundance in low-lying vegetation. S. marginelineatus and P. flavicosta were more frequent on Sida rhombifolia L. and Althernantera tenella Colla, respectively, whereas A. albidula was observed more often on Conyza bonariensis (L.) Cronq. and B. hebe only occurred on grasses. DNA samples of field-collected S. marginelineatus were positive by polymerase chain reaction and sequencing tests for the presence of the HLB-phytoplasma group, indicating it as a potential vector. The association of leafhoppers with their hosts may be used in deciding which management strategies to adopt against weeds and diseases in citrus orchards. PMID:22606800

Marques, R N; Teixeira, D C; Yamamoto, P T; Lopes, J R S

2012-04-01

332

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

PubMed

'Candidatus Liberibacter asiaticus' (CLas) is a Gram-negative ?-proteobacterium, and the prominent species of Liberibacter associated with a devastating worldwide citrus disease known as huanglongbing (HLB). This fastidious bacterium resides in phloem sieve cells of host plants and is vectored by the Asian citrus psyllid (Diaphorina citri). Due to its uneven distribution in planta and highly variable bacterial titers, detection of HLB bacteria can be challenging. Here we demonstrated a new utility of nearly identical tandem-repeats of two CLas prophage genes for real-time PCR by SYBR Green 1 (LJ900fr) and TaqMan(®) (LJ900fpr). When compared with conventional 16S rDNA-based real-time PCR, targeting the repeat sequence reduced the relative detectable threshold by approximately 9 and 3 real-time PCR cycles for LJ900fr and LJ900fpr, respectively. Additionally, both LJ900 methods detected CLas from otherwise non-detectable samples by other methods. CLas was also detected from globally derived samples including psyllids, various citrus varieties, periwinkle, dodder, and orange jasmine, suggesting the new detection method can be applicable worldwide. Additionally, we demonstrated the presence of the hyv(I)/hyv(II) repeat sequence within the 'Ca. Liberibacter americanus' strain. The method thereby provides sensitive HLB detection with broad application for scientific, regulatory, and citrus grower communities. PMID:22245034

Morgan, J Kent; Zhou, Lijuan; Li, Wenbin; Shatters, Robert G; Keremane, Manjunath; Duan, Yong-Ping

2012-04-01

333

Habitat selection strategies of mosquitoes inhabiting citrus irrigation furrows.  

PubMed

The mosquitoes Aedes vexans, Psorophora columbiae and Psorophora howardii have recently extended their habitat distribution into citrus irrigation furrows in coastal southeastern Florida. Oviposition site selection was examined by correlating species abundances with water depths due to rainfall or flood irrigation. Psorophora columbiae and Ps. howardii oviposited low in furrows, shared similar distributional relationships to water depths and were hatched by rainfall or irrigation. Aedes vexans oviposted higher in the citrus furrow, showed a different relationship to water depth and were hatched only by flood irrigation. PMID:2906662

Curtis, G A

1985-06-01

334

S-methylmethionine sulfonium in fruits of citrus hybrids.  

PubMed

The S-methylmethionine sulfonium (MMS) concentrations in fruits of citrus hybrids were measured, and found to increase during ripening of the fruit. However, there of eleven hybrids of 'Seto unshiu' crossed with 'Morita ponkan' and four of 9 hybrids of 'Murcott' tangor crossed with 'Seto unshiu' had low MMS concentrations even at late harvest stage. Crossbreeding is useful in producing new citrus fruits that have juices with the desirable characteristics of their parents without formation of dimethyl sulfide which is an off-flavor. PMID:8987599

Sakamoto, K; Inoue, A; Nakatani, M; Kozuka, H; Ohta, H; Osajima, Y

1996-09-01

335

Energy conservation in citrus processing. Final project report  

SciTech Connect

Alternative energy conserving systems for use in citrus processing plants were synthesized and evaluated in terms of energy savings and economic return. The energy intensive operations that are carried out in citrus processing plants include conveying and extraction, concentration, peel drying, refrigeration, and pasteurization. The alternative energy conserving systems are synthesized from components and subsystems that are arranged to make use of energy cascading and thermodynamic regeneration to reduce the overall energy usage. System requirements such as air pollution rules and plant processing load cycles, a characterization of major operations, description of alternative system concepts, and the evaluation of alternative systems in terms of economic parameters and energy usage are identified.

Leo, M.A.; Lari, R.I.; Moore, N.R.; Broussard, M.R.; Gyamfi, M.

1981-11-01

336

Resveratrol and its combination with ?-tocopherol mediate salt adaptation in citrus seedlings.  

PubMed

Resveratrol, a phytoalexin found in red wine, has the potential to impact a variety of human diseases but its function in plants exposed to stressful conditions is still unknown. In the present study the effect of exogenous application of resveratrol (Res), ?-tocopherol (?-Toc) and their combination (Res + ?-Toc) in salt adaptation of citrus seedlings was investigated. It was found that Res, ?-Toc or Res + ?-Toc treatments reduced NaCl-derived membrane permeability (EL), lipid peroxidation (MDA) and pigments degradation, whereas companied Res and ?-Toc application also reduced H2O2 accumulation in leaves and restored the reduction of photosynthesis induced by NaCl. Application of Res under salinity retained Cl(-) in roots while Res + ?-Toc reduced the translocation of Na(+) and Cl(-) to leaves. Carbohydrates and proline, phenols, total ascorbic acid and glutathione were remarkably affected by NaCl as well as by chemical treatments in leaves and roots of citrus. NaCl treatment increased the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD), glutathione reductase (GR), polyphenol oxidase (PPO) in leaves while SOD and POD activities were decreased in roots by this treatment. Also, Res, ?-Toc or Res + ?-Toc treatments displayed tissue specific activation or deactivation of the antioxidant enzymes. Overall, this work revealed a new functional role of Res in plants and provided evidence that the interplay of between Res and ?-Toc is involved in salinity adaptation. PMID:24602773

Kostopoulou, Zacharoula; Therios, Ioannis; Molassiotis, Athanassios

2014-05-01

337

Viability of 'Candidatus Liberibacter asiaticus' prolonged by addition of citrus juice to culture medium.  

PubMed

Huanglongbing, or citrus greening disease, is associated with infection by the phloem-limited bacterium 'Candidatus Liberibacter asiaticus'. Infection with 'Ca. L. asiaticus' is incurable; therefore, knowledge regarding 'Ca. L. asiaticus' biology and pathogenesis is essential to develop a treatment. However, 'Ca. L. asiaticus' cannot currently be successfully cultured, limiting its study. To gain insight into the conditions conducive for growth of 'Ca. L. asiaticus' in vitro, 'Ca. L. asiaticus' inoculum obtained from seed of fruit from infected pomelo trees (Citrus maxima 'Mato Buntan') was added to different media, and cell viability was monitored for up to 2 months using quantitative polymerase chain reaction in conjunction with ethidium monoazide. Media tested included one-third King's B (K), K with 50% juice from the infected fruit, K with 50% commercially available grapefruit juice, and 100% commercially available grapefruit juice. Results show that juice-containing media dramatically prolong viability compared with K in experiments reproduced during 2 years using different juice sources. Furthermore, biofilm formed at the air-liquid interface of juice cultures contained 'Ca. L. asiaticus' cells, though next-generation sequencing indicated that other bacterial genera were predominant. Chemical characterization of the media was conducted to discuss possible factors sustaining 'Ca. L. asiaticus' viability in vitro, which will contribute to future development of a culture medium for 'Ca. L. asiaticus'. PMID:23883155

Parker, Jennifer K; Wisotsky, Sarah R; Johnson, Evan G; Hijaz, Faraj M; Killiny, Nabil; Hilf, Mark E; De La Fuente, Leonardo

2014-01-01

338

Xanthomonas axonopodis pv. citri enters the VBNC state after copper treatment and retains its virulence.  

PubMed

The most severe form of citrus canker disease is caused by Xanthomonas axonopodis pv. citri (Xac) and affects all types of important citrus crops, reducing fruit yield and quality. Copper-based products are routinely used as a standard control measure for citrus canker. In this work we demonstrate that copper treatment induces the viable but nonculturable (VBNC) state in Xac but does not prevent the development of symptoms in susceptible plants. Short-term exposures to different concentrations of copper solutions were assayed to determine which treatment resulted in Xac nonculturability. Treatment of 10(6) mL(-1) Xac cells for 10 min in a 135-muM CuSO(4) solution (equivalent to three times the free soluble copper concentration applied in one field treatment) resulted in nonculturability. However, 16% of cells were viable based on 5-cyano-2,3-ditolyl tetrazolium chloride staining and 1% were capable of producing canker lesions after infiltrating grapefruit plants. If induction of the VBNC state in Xac cells were to occur under field conditions, this would have to be taken into consideration for an effective control of canker disease. PMID:19624747

del Campo, Raquel; Russi, Paola; Mara, Pamela; Mara, Héctor; Peyrou, Mercedes; de León, Inés Ponce; Gaggero, Carina

2009-09-01

339

Estimation of the number of aphids carrying Citrus tristeza virus that visit adult citrus trees.  

PubMed

Aphid species were counted on citrus trees in orchards in Valencia, Spain, in the spring and autumn of 1997, 1998 and 1999. Moericke yellow water traps, the 'sticky shoot' method and counts of established colonies were used in extensive surveys in which 29,502 aphids were recorded and identified. Aphis spiraecola and Aphis gossypii were the most abundant aphid species. The numbers of aphid species landing on mature trees of grapefruit, sweet orange, lemon and clementine and satsuma mandarins, were estimated by counting the numbers of young shoots/tree and aphids trapped on sticky shoots. The proportions of the different aphid species captured were: A. gossypii (53%), A. spiraecola (32%), Toxoptera aurantii (11%), Myzus persicae (1%), Aphis craccivora (1%) and other species (2%). Clementine was the most visited species with 266,700 aphids landing/tree in spring 2000, followed by lemon (147,000), sweet orange (129,150), grapefruit (103,200), and satsuma (92,400). The numbers and relative percentages of aphids carrying Citrus tristeza virus (CTV) were assessed by nested RT-PCR in single closed tubes and analysed by extraction of RNA-CTV targets from trapped aphids. An average of 37,190 CTV-carrying aphids visited each tree in spring 2000 (29 per shoot). The percentage detection of viral RNA in the aphid species that landed were 27% for A. gossypii, 23% for A. spiraecola and 19% for T. aurantii. This high incidence of aphids carrying CTV is consistent with the high prevalence and rapid spread of CTV in sweet orange, clementine, and satsuma mandarins in recent years in the region. The infection rate was proportional to the number of aphids landing/tree. PMID:15036840

Marroquín, Carlos; Olmos, Antonio; Teresa Gorris, María; Bertolini, Edson; Carmen Martínez, M; Carbonell, Emilio A; Hermoso de Mendoza, Alfonso; Cambra, Mariano

2004-03-01

340

Emergence and Phylodynamics of Citrus tristeza virus in Sicily, Italy  

PubMed Central

Citrus tristeza virus (CTV) outbreaks were detected in Sicily island, Italy for the first time in 2002. To gain insight into the evolutionary forces driving the emergence and phylogeography of these CTV populations, we determined and analyzed the nucleotide sequences of the p20 gene from 108 CTV isolates collected from 2002 to 2009. Bayesian phylogenetic analysis revealed that mild and severe CTV isolates belonging to five different clades (lineages) were introduced in Sicily in 2002. Phylogeographic analysis showed that four lineages co-circulated in the main citrus growing area located in Eastern Sicily. However, only one lineage (composed of mild isolates) spread to distant areas of Sicily and was detected after 2007. No correlation was found between genetic variation and citrus host, indicating that citrus cultivars did not exert differential selective pressures on the virus. The genetic variation of CTV was not structured according to geographical location or sampling time, likely due to the multiple introduction events and a complex migration pattern with intense co- and re-circulation of different lineages in the same area. The phylogenetic structure, statistical tests of neutrality and comparison of synonymous and nonsynonymous substitution rates suggest that weak negative selection and genetic drift following a rapid expansion may be the main causes of the CTV variability observed today in Sicily. Nonetheless, three adjacent amino acids at the p20 N-terminal region were found to be under positive selection, likely resulting from adaptation events.

Davino, Salvatore; Willemsen, Anouk; Panno, Stefano; Davino, Mario; Catara, Antonino; Elena, Santiago F.; Rubio, Luis

2013-01-01

341

Comparison of some biochemical characteristics of different citrus fruits  

Microsoft Academic Search

The goal of this investigation was to evaluate the antioxidant properties of some citrus fruits. The contents of dietary fibre, total polyphenols, essential phenolics, ascorbic acid and some trace elements of lemons, oranges and grapefruits were determined and compared with their total radical-trapping antioxidative potential (TRAP). There were no significant differences in the contents of total, soluble and insoluble dietary

Shela Gorinstein; Olga Mart??n-Belloso; Yong-Seo Park; Ratiporn Haruenkit; Antonin Lojek; Milan ???ž; Abraham Caspi; Imanuel Libman; Simon Trakhtenberg

2001-01-01

342

A stable RNA virus-based vector for citrus trees  

SciTech Connect

Virus-based vectors are important tools in plant molecular biology and plant genomics. A number of vectors based on viruses that infect herbaceous plants are in use for expression or silencing of genes in plants as well as screening unknown sequences for function. Yet there is a need for useful virus-based vectors for woody plants, which demand much greater stability because of the longer time required for systemic infection and analysis. We examined several strategies to develop a Citrus tristeza virus (CTV)-based vector for transient expression of foreign genes in citrus trees using a green fluorescent protein (GFP) as a reporter. These strategies included substitution of the p13 open reading frame (ORF) by the ORF of GFP, construction of a self-processing fusion of GFP in-frame with the major coat protein (CP), or expression of the GFP ORF as an extra gene from a subgenomic (sg) mRNA controlled either by a duplicated CTV CP sgRNA controller element (CE) or an introduced heterologous CE of Beet yellows virus. Engineered vector constructs were examined for replication, encapsidation, GFP expression during multiple passages in protoplasts, and for their ability to infect, move, express GFP, and be maintained in citrus plants. The most successful vectors based on the 'add-a-gene' strategy have been unusually stable, continuing to produce GFP fluorescence after more than 4 years in citrus trees.

Folimonov, Alexey S.; Folimonova, Svetlana Y. [Department of Plant Pathology, University of Florida, Citrus Research and Education Center, 700 Experiment Station Road, Lake Alfred, FL 33850 (United States); Bar-Joseph, Moshe [The Volcani Center, Bet-Dagan 50259 (Israel); Dawson, William O. [Department of Plant Pathology, University of Florida, Citrus Research and Education Center, 700 Experiment Station Road, Lake Alfred, FL 33850 (United States)], E-mail: wodtmv@crec.ifas.ufl.edu

2007-11-10

343

Metal binding by citrus dehydrin with histidine-rich domains  

Microsoft Academic Search

Dehydrins are hydrophilic proteins that are responsive to osmotic stress, such as drought, cold, and salinity in plants. Although they have been hypothesized to stabi- lize macromolecules in stressed cells, their functions are not fully understood. Citrus dehydrin, which accu- mulates mainly in response to cold stress, enhances cold tolerance in transgenic tobacco by reducing lipid peroxidation. It has been

Masakazu Hara; Masataka Fujinaga; Toru Kuboi

2005-01-01

344

Viscometric control in the enzymatic extraction of citrus peel oils  

Microsoft Academic Search

Enzymatic treatment during the industrial extraction of lemon-peel oil allows the aqueous discharges from centrifuges to be recycled towards the extractors. Emulsions with stabilized and reduced viscosity are essential for centrifuges to work efficiently. In citrus processing plants, enzyme is added in a manual operation with no viscosity control. However, the correct measurement of this parameter makes it possible to

L. Coll; D. Saura; M. P. Ruiz; J. M. Ros; J. A. Cánovas; J. Laencina

1995-01-01

345

Comparative Physical Examination of Various Citrus Peel Essential Oils  

Microsoft Academic Search

Physical parameters of various citrus peel essential oils were determined in this study. Essential oils from the peels of Kinnow (C. reticulata, var. mandarin), Fewtrell's early (C. reticulata, var. tangerine), Malta (C. sinensis var. malta), Mousami (C. sinensis var. mousami), grape fruit (C. paradisi) and eureka lemon (C. limon) were extracted by applying cold expressing method. Eureka lemon had the

MUHAMMAD MUSHTAQ AHMAD; FAQIR MUHAMMAD ANJUM; EHSAN ELAHI BAJWA

2006-01-01

346

Low Energy Technology. A Unit of Instruction in Citrus Production.  

ERIC Educational Resources Information Center

This unit of instruction on citrus production was designed for use by agribusiness and natural resources teachers in Florida high schools and by agricultural extension agents as they work with adults and students. It is one of a series of 11 instructional units (see note) written to help teachers and agents to educate their students and clients…

Olson, Jeanne A.; Becker, William J.

347

Study of pulsed electric field treated citrus juices  

Microsoft Academic Search

The effect of pulsed electric field (PEF) treatment, applied in a continuous system, on physical and chemical properties of freshly squeezed citrus juices (grapefruit, lemon, orange, tangerine) was studied. The aim of the present work was to investigate the effect of PEF technology on pH, Brix°, electric conductivity, viscosity, nonenzymatic browning index (NEBI), hydroxymethylfurfurol (HMF), color, organic acid content, and

Zs. Cserhalmi; Á. Sass-Kiss; M. Tóth-Markus; N. Lechner

2006-01-01

348

Complete Mix Activated Sludge Treatment of Citrus Process Wastes.  

National Technical Information Service (NTIS)

A full-scale, complete mixed activated sludge treatment system effectively treats concentrated citrus process wastes. This process has a BOD reduction capability of 99 percent; but it produces 0.5 to 0.6 pounds of waste sludge per pound of influent BOD. T...

1971-01-01

349

Larvicidal Activity of Citrus Limonoids against Aedes albopictus Larvae  

PubMed Central

Background: Development of insecticide resistance occurred due to the continuous and misuse of synthetic insecticides therefore, the recent study was conducted to explore eco-friendly plant extracts that have some potential to suppress mosquito larval population. Methods: WHO recommended mosquito larval bioassay method for insecticide was used while for the analysis of citrus oils for limonin and nomilin content HPLC was used. Results: Among the two citrus cultivars tested as larvicide against Aedes albopictus, valencia late (Citrus sinensis) was the best in terms of LC50 (297 ppm), % mortality (97%) and LT50 (18.49 hours) then freutrall early (Citrus reticulate) with LC50 (377.4 ppm), % mortality (88%) and LT50 (31 hours), While nomilin gave lowest LC50 (121.04 ppm) than limonin (382.22 ppm) after 72 hours of exposure. Valencia late also had more limonin and nomilin (377 ?g/ml and 21.19 ?g/ml) than freutrall early (5.29 ?g/ml and 3.89 ?g/ml) respectively. Conclusion: Valencia late showed best results in term of LC50, LT50 and percentage mortality against Aedes albopictus as it has more amount of nomilin then freutrall early, however further evaluation in the field conditions is required.

Bilal, Hazrat; Akram, Waseem; Ali-Hassan, Soaib

2012-01-01

350

Exactly which synephrine alkaloids does Citrus aurantium (bitter orange) contain?  

Microsoft Academic Search

Following the withdrawal of ephedrine from the dietary supplement marketplace sales of products containing Citrus aurantium (CA) (bitter orange) for weight loss are believed to have increased dramatically. CA contains a number of constituents speculated to lead to weight loss, of which the most frequently cited constituent is synephrine. Concerns have been raised about the safety of products containing synephrine.

D B Allison; G Cutter; E T Poehlman; D R Moore; S Barnes

2005-01-01

351

Adverse reaction to an adrenergic herbal extract ( Citrus aurantium)  

Microsoft Academic Search

We report the case of a 52 year old woman that had an adverse reaction after taking a dry herbal extract of an unripe fruit of Citrus aurantium L. var. amara, as dietary supplement for weight loosing. The fruit is also known as zhi shi (in traditional Chinese Medicine) or bitter orange in other parts of the world.

F. Firenzuoli; L. Gori; C. Galapai

2005-01-01

352

The Chemical Composition of Some Mediterranean Citrus Oils  

Microsoft Academic Search

To compare the regional variations of the quantitative chemical composition, some Mediterranean citrus oils (lemon, sweet orange, bitter orange, and mandarin) from Italy and Spain have been studied. Over 100 constituents were identified in the various oils, from which 80 components could be quantified.No significant differences were found in the concentrations of the main constituents of sweet orange oils from

Mans H. Boelens; Rafael Jimenez

1989-01-01

353

The Oxygen Heterocyclic Compounds of Citrus Peel Oils  

Microsoft Academic Search

The occurrence of oxygen heterocyclic compounds in the peel oils from different Citrus species has been investigated by high performance liquid chromatography. The use of a photodiode array detector has facilitated the identification and quantification of the individual coumarins, psoralens and polymethoxyflavones present. Certain oxygen heterocyclic compounds are unique to a particular species, but the majority occur widely in the

David McHale; John B. Sheridan

1989-01-01

354

New acridone from the wood of Citrus reticulata Blanco.  

PubMed

A new acridone, named citruscridone (1) together with five known compounds were isolated from the wood of Citrus reticulata Blanco. Their structures were established based on spectroscopic evidence. The antibacterial and antifungal activities of the wood extracts and pure compounds were evaluated. PMID:23697332

Phetkul, Uraiwan; Wanlaso, Nutthakran; Mahabusarakam, Wilawan; Phongpaichit, Souwalak; Carroll, Anthony R

2013-10-01

355

Flavour quality of dehydrated lime [ Citrus aurantifolia (Christm.) Swingle  

Microsoft Academic Search

The hydro-distilled volatile oils of fresh and dehydrated lime [Citrus aurantifolia (Christm.) Swingle] fruit were subjected to GC and GC–MS. A total of 32 compounds, constituting > 98% of the volatiles of fresh lime fruit, were identified. Five sesquiterpene hydrocarbons and two sesquiterpene alcohols were found and identified for the first time in lime fruit. The volatiles from the dehydrated

A. Ramesh Yadav; A. S. Chauhan; M. N. Rekha; L. J. M. Rao; R. S. Ramteke

2004-01-01

356

Comercializacion de productos derivados del Limon Mexicano (Citrus aurantifolia swingle)  

Microsoft Academic Search

The present study analyzes the productive structure and the yield of the companies extractors of derivatives of the mexican lime (Citrus aurantifolia Swingle) in Mexico, by means of the generation of quantitative indicators. The margins of commercialization of different products elaborated by the industry calculated; also they were studied the enterprises profitability. The study is referred to the analysis of

Felipe de Jesus Gonzalez Razo; Rolando Rojo Rubio; Orsohe Ramirez Abarca; Jose Miguel Omana Silvestre; Jaime Arturo Matus Gardea; Samuel Rebollar Rebollar

2009-01-01

357

The draft genome of sweet orange (Citrus sinensis).  

PubMed

Oranges are an important nutritional source for human health and have immense economic value. Here we present a comprehensive analysis of the draft genome of sweet orange (Citrus sinensis). The assembled sequence covers 87.3% of the estimated orange genome, which is relatively compact, as 20% is composed of repetitive elements. We predicted 29,445 protein-coding genes, half of which are in the heterozygous state. With additional sequencing of two more citrus species and comparative analyses of seven citrus genomes, we present evidence to suggest that sweet orange originated from a backcross hybrid between pummelo and mandarin. Focused analysis on genes involved in vitamin C metabolism showed that GalUR, encoding the rate-limiting enzyme of the galacturonate pathway, is significantly upregulated in orange fruit, and the recent expansion of this gene family may provide a genomic basis. This draft genome represents a valuable resource for understanding and improving many important citrus traits in the future. PMID:23179022

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

2013-01-01

358

OXIDANT AIR POLLUTION AND WORK PERFORMANCE OF CITRUS HARVEST LABOR  

EPA Science Inventory

The project assesses the effect of photochemical oxidants on the work performance of twelve individual citrus pickers in the South Coast Air Basin of southern California. A model of the picker's decision problem is constructed in which oxidants influence the individual's picking ...

359

Citrus orchards management and soil water repellency in Eastern Spain  

NASA Astrophysics Data System (ADS)

Water repellent soils are found around the world, although originally was found on fire affected soil (DeBano, 1981). However, for decades, water repellency was found to be a rare soil property. One of the pioneer research that shown that water repellency was a common soil property is the Wander (1949) publication in Science. Wander researched the water repellency on citrus groves, and since then, no information is available about the water repellency on citrus plantations. The Mediterranean soils are prone to water repellency due to the summer dry conditions (Cerdà and Doerr, 2007). And Land Use and Land Management are key factors (Harper et al., 2000; Urbanek et al., 2007) to understand the water repellency behaviour of agriculture soils. Valencia region (Eastern Spain) is the largest exporter in the world and citrus plantations located in the alluvial plains and fluvial terraces are moving to alluvial fans and slopes where the surface wash is very active (Cerdà et al., 2009). This research aims to show the water repellency on citrus orchards located on the sloping terrain (< 15 % angle slope). Measurement were conducted in four experimental plots located in the Canyoles River watershed to assess the soil water repellency in citrus orchards under different managements: annual addition of plant residues and manure with no tilling and no fertilizer (MNT), annual addition of plant residues with no tillage (NT), application of conventional herbicides and no tilling (HNT) and conventional tillage in June (CT). The period for each type of management ranged from 2 and 27 (MNT), 1 and 25 (NT), 2 and 27 (HNT) and 3 and 29 years (CT). At each plot, a ten points were selected every 10 cm along inter-rows and water drop penetration time test (WDTP; DeBano, 1981) was performed. The results show that the MNT treatment induced slight water repellency in citrus-cropped soils compared to other treatments. Small but significant soil water repellency was observed under NT and HNT treatments (mean WDTP 4 ± 4 s and 2 ± 2 s, respectively), which may be regarded as subcritical soil water repellency. Slight water repellency observed in soils under MNT treatment may be attributed to the input of hydrophobic organic compounds as a consequence of the addition of plant residues and organic manure. A further issue to be achieved is the study of geomorphological processes associated to sub-critical soil water repellency. The experimental setup within the citrus plantation is being supported by the research project CGL2008-02879/BTE

Cerdà, A.; González Peñaloza, F. A.; Jordán, A.; Zavala, L. M.

2012-04-01

360

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

PubMed

The Asian citrus psyllid (ACP), Diaphorina citri (Hemiptera: Psyllidae) is the primary vector of the bacterium causing citrus huanglongbing (citrus greening), the most serious disease of citrus worldwide. Psyllids and other hemipterans produce large amounts of honeydew, which has been used previously as an indicator of phloem sap composition and insect feeding or metabolism. Behavioral, ultrastructural and chemical studies on ACP, its honeydew and waxy secretions showed important differences between nymphs, males and females, and suggested some mechanisms by which the psyllids, especially nymphs and adult females, can minimize their contamination with honeydew excretions. The anal opening in ACP, near the posterior end of the abdomen, is on the ventral side in nymphs and on the dorsal side in adult males and females. Video recordings showed that adult males produce clear sticky droplets of honeydew gently deposited behind their body on the leaf surface, whereas adult females produce whitish honeydew pellets powerfully propelled away from the female body, probably to get their excretions away from eggs and newly hatched nymphs. ACP nymphs produce long ribbons or tubes of honeydew that frequently stay attached to the exuviae after molting, or drop when feeding on the lower side of citrus leaves. Furthermore, honeydew excretions of both nymphs and adult females are covered with a thin layer of whitish waxy material ultrastructurally composed of a convoluted network of long fine filaments or ribbons. This material is extruded from intricate arrays of wax pores in the circumanal ring (around the anus) that is found in nymphs and females but not in males of ACP or other psyllid species. Infrared microscopy and mass spectroscopy revealed that, in addition to various sugars, honeydew excretions of ACP nymphs and females are covered with a thin layer of wax similar in profile to ester waxes. PMID:23762268

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

2013-01-01

361

Field evaluation of a plant activator, captan, chlorothalonil, copper hydroxide, iprodione, mancozeb and strobilurins for the control of citrus brown spot of mandarin  

Microsoft Academic Search

Brown spot (caused by Alternaria alternata) is a major disease of citrus in subtropical areas of Australia. A number of chemicals, the strobilurins azoxystrobin, trifloxystrobin,\\u000a pyraclostrobin and methoxycrylate, a plant activator (acibenzolar), copper hydroxide, mancozeb, captan, iprodione and chlorothalonil\\/pyrimthanil\\u000a were tested in the field for its control. Over three seasons, trees in a commercial orchard received 16, 14 and 7

A. K. Miles; S. L. Willingham; A. W. Cooke

2005-01-01

362

In Vitro Fermentation of Cellulose, Beet Pulp, Citrus Pulp, and Citrus Pectin Using Fecal Inoculum from Cats, Dogs, Horses, Humans, and Pigs and Ruminal Fluid from Cattle  

Microsoft Academic Search

We evaluated the influence of gas- trointestinal tract microflora from several species on fiber fermentation characteristics in vitro. Selected fibrous substrates (cellulose, beet pulp, citrus pulp, and citrus pectin) were incubated for 6, 12, 24, and 48 h with ruminal fluid from cattle or feces from dogs, cats, pigs, horses, or humans. When data were pooled across all substrates and

G. D. Sunvold; H. S. Hussein; G. C. Fahey; N. R. Merchen; G. A. Reinhart

2010-01-01

363

The distribution and abundance of phytoseiid mites (Acari: Phytoseiidae) on citrus in southern Africa and their possible value as predators of citrus thrips (Thysanoptera: Thripidae)  

Microsoft Academic Search

On citrus in Zimbabwe, Swaziland and South Africa, predacious mites of the subfamily Amblyseiinae are more common and found in greater numbers than phytoseiids of the subfamily Phytosciinae. The author's survey and other collection data indicated that within the Amblyseiinae the genus Euseius Wainstein is the most widely distributed. Seven Euseius spp. have been recorded on citrus in the above

T. G. Grout

1994-01-01

364

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

PubMed

Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is an important pest of citrus. It is an efficient vector of three bacterial pathogens that are the presumptive causal agents of huanglongbing (HLB) or citrus greening disease. The movement patterns and dispersal capabilities of D. citri require study to better understand the spread of HLB and to improve management strategies for D. citri. A recently developed immunomarking technique that uses crude food proteins (chicken egg albumin, bovine casein, and soy protein) was evaluated for marking and tracking movement of D. citri in Florida citrus groves. In general, both egg and milk protein markers exhibited longer residual activity (35 d) than the soy protein marker (20 d) when applied to citrus leaves with a residual activity order of egg > milk > soy protein. However, residues of all three protein markers decreased with a simulated rain; this was more pronounced for soy protein than for egg and milk proteins. Temperature did not significantly affect acquisition of markers by adult D. citri. Egg, milk, and soy protein markers were detected on >90% of adult D. citri for up to 10, 10, and 5 d, respectively, after field application. Addition of tetrasodium ethylenediamine tetraacetic acid (water softener) and/or Silwet L-77 (wetting agent) to marker solutions did not affect longevity of detection. Each of the protein markers was detected on > or =80% of exposed D. citri for up to 30 d after direct application to adults. A field study was conducted to measure movement of D. citri between replicated pairs of 0.4 ha managed and unmanaged citrus plots separated by 60-100 m. Approximately 70% of captured D. citri were found marked 3 d after application of proteins in the field. Using two marker proteins, it was determined that D. citri moved bi-directionally between managed and unmanaged (abandoned) groves within 3 d with a greater number of D. citri adults moving from unmanaged into managed plots than from managed into unmanaged plots (net movement). These data indicate frequent movement by adult D. citri between groves and suggest that unmanaged groves may act as refuge sites for D citri, leading to reinfestation of nearby managed groves. PMID:19689907

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

2009-08-01

365

Effects of different citrus varieties on the developmental behaviour of Citrus Butterfly Papilio demoleus in lower Sindh, Pakistan  

Microsoft Academic Search

The consumption of ten different varieties of citrus plantation by butterfly Papilio demoleus and its effects on its larval and postlarval development were studied at Tando Mohammad Khan, Lower Sindh. Different type of food showed significant effects on growth rate, food utilization and reproductive potential of this pest. It was revealed that the growth index value was highest being 13.84

Arshad Munir; Nikliat Yasmin; M. Ather Rafi

366

Longidorus ferrisi n. sp. from California Citrus  

PubMed Central

In October 1999, the authors received fixed specimens of a species of Longidorus from Howard Ferris found about the roots of a citrus tree in Oakville, Napa County, CA. After determining it to be new a species, we requested additional specimens. The samples contained roughly equal numbers of males and females. Longidorus ferrisi n. sp. is most similar to L. elongatus, but can be distinguished by a greater c-ratio (111-187 vs 73-141), a lesser c´ (0.7-1.1 vs 1.0-1.3), a more offset head, a more posterior guide ring (35-40 vs 30-33 ?m), the presence of sperm in the uterus in mature females, and the approximate 1:1 ratio of females to males. Other similar species include L. artemisiae, L. crassus, L. glycines, and L. milanis. Longidorus ferrisi n. sp. differs from L. artemisiae by a lesser a-ratio (74-102 vs 109-155), a lesser c´ value (0.7-1.1 vs 1.0-1.6), a more posterior guide ring (35-40 vs 27-34 ?m), a longer odontostyle (91-108 vs 84-98 ?m), a wider lip region (16-19 vs 14-17 ?m), wider mid-body (53-69 vs 41-52 ?m), and longer spicules (57-65 vs 39-49 ?m). The new species differs substantially from L. crassus by its lip shape and the presence of males, and differs from L. glycines by a shorter body (4.33-5.97 vs 6.14-8.31 mm), a lesser c´ value (0.7-1.1 vs 0.9-1.4), a narrower lip region (16-19 vs 20-23 ?m), wider mid-body (53-69 vs 39-57 ?m), longer spicules (53-69 vs 45-53 ?m), and fewer supplements (7-11 vs 11-17). Longidorus ferrisi n. sp. differs from L. milanis by a longer body (4.33-5.97vs 3.00-4.90 mm), a greater c value (111-187 vs 86-130), a wider mid-body (53-69 vs 43-56 ?m), a different head shape, and longer spicules (53-69 vs 41-54 ?m). The nuclear 18S ribosomal DNA sequence of this species revealed that this species is unique with respect to all sequenced Longidorus species.

Ye, Weimin; Pedram, Majid

2009-01-01

367

Identification of two chilling-regulated 1-aminocyclopropane-1-carboxylate synthase genes from citrus (Citrus sinensis Osbeck) fruit.  

PubMed

Diurnal change in the temperature below or above 12.5 degrees C hastens the degreening of citrus peel and elicits the phytohormone ethylene production in citrus fruit. Ethylene triggers the degradation of chlorophyll and synthesis of carotenoids in citrus peel. To investigate if ethylene is required for the degreening of citrus peel elicited by low temperatures, we studied the chilling-regulated gene expression of ACC synthase, one of the key enzymes catalyzing ethylene biosynthesis. We isolated and characterized a chilling-inducible 1-aminocyclopropane-1-carboxylate synthase (ACC synthase) gene, CS-ACS1, and a chilling-repressible gene, CS-ACS2, from citrus peel. The CS-ACS1 transcript 1.7 kb in length encodes a polypeptide of 483 amino acids (Mr 54,115, pI 6.63), whereas the CS-ACS2 transcript of 1.8 kb encodes a polypeptide of 477 amino acids (Mr 53,291, pI 6.72). Both genes showed a rapid but transient induction (within 2.4 h) of transcripts upon rewarming after the chilling (4 degrees C) treatment. After 24 h of incubation at room temperature, CS-ACS1 mRNA diminished to an undetectable level, whereas the CS-ACS2 mRNA regained its basal level of expression attained prior to the chilling treatment. Chilling-induced ethylene production and ACC accumulation were also observed upon rewarming. Both genes were also induced by the wound stress (excision). The protein synthesis inhibitor cycloheximide super-enhances the accumulation of both ACS transcripts at room temperature. Molecular analysis of the 3.3 kb genomic DNA of CS-ACS1 revealed that this gene consists of three introns and four exons. The intron 3 is exceptionally large ( 1.2 kb) and shares significant homology with mitochondrial DNA, supporting the intron-late theory. PMID:10645719

Wong, W S; Ning, W; Xu, P L; Kung, S D; Yang, S F; Li, N

1999-11-01

368

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

PubMed

The Asian citrus psyllid, Diaphorina citri Kuwayama, vectors Candidatus Liberibacter asiaticus (Las) and Candidatus Liberibacter americanus (Lam), the presumed causal agents of huanglongbing. D. citri generally rely on olfaction and vision for detection of host cues. Plant volatiles from Allium spp. (Alliaceae) are known to repel several arthropod species. We examined the effect of garlic chive (A. tuberosum Rottl.) and wild onion (A. canadense L.) volatiles on D. citri behaviour in a two-port divided T-olfactometer. Citrus leaf volatiles attracted significantly more D. citri adults than clean air. Volatiles from crushed garlic chive leaves, garlic chive essential oil, garlic chive plants, wild onion plants and crushed wild onion leaves all repelled D. citri adults when compared with clean air, with the first two being significantly more repellent than the others. However, when tested with citrus volatiles, only crushed garlic chive leaves and garlic chive essential oil were repellent, and crushed wild onions leaves were not. Analysis of the headspace components of crushed garlic chive leaves and garlic chive essential oil by gas chromatography-mass spectrometry revealed that monosulfides, disulfides and trisulfides were the primary sulfur volatiles present. In general, trisulfides (dimethyl trisulfide) inhibited the response of D. citri to citrus volatiles more than disulfides (dimethyl disulfide, allyl methyl disulfide, allyl disulfide). Monosulfides did not affect the behaviour of D. citri adults. A blend of dimethyl trisulfide and dimethyl disulfide in 1:1 ratio showed an additive effect on inhibition of D. citri response to citrus volatiles. The plant volatiles from Allium spp. did not affect the behaviour of the D. citri ecto-parasitoid Tamarixia radiata (Waterston). Thus, Allium spp. or the tri- and di-sulphides could be integrated into management programmes for D. citri without affecting natural enemies. PMID:20609277

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

2011-02-01

369

Citrus extract or natamycin treatments on "Tzatziki" - a traditional Greek salad.  

PubMed

The effect of packaging (aerobic and vacuum) either with citrus extract, natamycin individually added, or the combination of two, was studied on the shelf-life of a Greek traditional deli salad "Tzatziki" during storage under refrigeration (4°C). Irrespective of the packaging conditions and treatments, yeasts populations of approximately 4.0-6.5logcfu/g were recorded in the microflora of the salad, whereas the Pseudomonas spp. populations were lower (2-3logcfu/g). Tzatziki's overall flavour was better under vacuum, and of all the treatments examined, the addition of citrus extract, and to a letter extent the combination with natamycin, improved the taste and odour (fruity, pleasant, refreshing with reduced garlic typical flavour) of Tzatziki salad. The shelf-life of Tzatziki was extended by ca. >10days (citrus extract, citrus-natamycin) and 5-6days (natamycin, citrus and citrus-natamycin) under aerobic or vacuum, respectively, as compared to the control sample. PMID:24001860

Tsiraki, Maria I; Savvaidis, Ioannis N

2014-01-01

370

Energy conservation in citrus processing. Technical progress report, October 1, 1979-March 31, 1980  

SciTech Connect

The Sunkist Citrus Plant in Ontario, California, processes about 6 million pounds of citrus fruit per day to make products which include frozen concentrated juice; chilled, pasteurized, natural strength juice; molasses from peel; dried meal from peel; pectin; citrus oil; and bioflavonoids. The energy intensive operations at the plant include concentration, drying, and refrigeration. The objective of the two-year two-phase project is to identify an economically viable alternative to the existing method of meeting energy requirements. Progress on the technical work of Phase I is reported. The following are summarized: requirements (energy price projection, atmospheric emission requirements, citrus juice quality constraints, economic evaluations); characterization (basic citrus processing operations, energy consumption and fruit processed vs time, identification and measurement of energy uses, energy balance for a typical citrus juice evaporator); and thermodynamic analysis (heat pump model, thermal evaporator, and co-generation model).

Not Available

1980-06-15

371

Karyological studies in ten species of Citrus(Linnaeus, 1753) (Rutaceae) of North-East India  

PubMed Central

Abstract Ten Citrus (Linnaeus, 1753) species of North-East India have been karyo-morphologically analysed. All studied species had 2n=18 chromosomes without any evidence of numerical variation. All the chromosomes were found to be of metacentric and sub-metacentric in all the species; the morphology of the chromosomes showing size difference only. Symmetrical karyotype which does not have much difference in the ratio of longest to shortest chromosome in all the species was observed. Three species, Citrus grandis (Osbeck, 1757), Citrus reticulata (Blanco, 1837) and Citrus medica (Linnaeus, 1753) are identified as true basic species from asymmetry studies of karyotypes as they reflect on the primitive nature of their genomes. Citrus indica (Tanaka, 1937)occupies a special taxonomic position within the genus Citrus as a progenitor for other cultivated species.

Hynniewta, Marlykynti; Malik, Surendra Kumar; Rao, Satyawada Rama

2011-01-01

372

Nitrogen and Phosphorus Fertilizer Requirements for Young, Bearing Microsprinkler-Irrigated Citrus, 2005 Report  

Microsoft Academic Search

Higher nutrient and water use efficiency are possible with microsprinkler- irrigated citrus compared to flood-irrigated citrus. Therefore, new N and P fertilizer recommendations are needed for microsprinkler-irrigated citrus. The objectives of these experiments were to i) determine the effects of N applications on tree growth, fruit yield, fruit and juice quality, and N and P removal in fruit for microsprinkler-irrigated

Thomas L. Thompson; Scott A. White; Ayako Kusakabe

373

Agrobacterium tumefaciens-mediated genetic transformation and plant regeneration from a complex tetraploid hybrid citrus rootstock  

Microsoft Academic Search

Agrobacterium-mediated genetic transformation of a tetraploid “tetrazyg” citrus rootstock selection ‘Orange #16’ [Nova mandarin (Citrus reticulata Blanco)+Hirado Buntan pummelo (Citrus grandis L. Osbeck)]×[Cleopatra mandarin (C. reticulata Blanco)+Argentine trifoliate orange (Poncirus trifoliata (L.) Raf.)] was performed. Juvenile epicotyl segments were transformed with a construct containing a bifunctional egfp–nptII fusion gene under the control of an enhanced double CaMV 35S promoter. Our

M. Dutt; J. Madhavaraj; J. W. Grosser

2010-01-01

374

Detection of Citrus tatter leaf virus with reverse transcription—polymerase chain reaction (RT-PCR)  

Microsoft Academic Search

Citrus tatter leaf virus (CTLV) has the potential to cause major losses to the Australian citrus industry if an infected clone is propagated, because\\u000a the predominant rootstocks are intolerant of CTLV infection. We have developed a robust and specific semi-nested reverse transcription—polymerase\\u000a chain reaction (RT-PCR) assay which detects CTLV in a range of citrus tissues. The sensitivity of the assay

D. L. Hailstones; K. L. Bryant; P. Broadbent; C. Zhou

2000-01-01

375

Growth, root morphology and boron uptake by citrus rootstock seedlings differing in boron-deficiency responses  

Microsoft Academic Search

Boron (B) is an essential microelement for higher plants and has important physiological functions in plant growth and development. Citrus plants are frequently exposed to B-deficiency, but knowledge regarding the effects of B-deficiency on rootstock growth, root morphology and genotypic variations in citrus is limited. To evaluate the variations in plant-growth parameters in response to B-deficiency, five citrus rootstocks seedlings

Li Mei; Ou Sheng; Shu-ang Peng; Gao-feng Zhou; Qing-jiang Wei; Qiao-hong Li

2011-01-01

376

Nitrogen and Phosphorus Fertilizer Requirements for Young, Bearing Microsprinkler-Irrigated Citrus, 2004 Report  

Microsoft Academic Search

Higher nutrient and water use efficiency are possible with microsprinkler- irrigated citrus compared to flood-irrigated citrus. Therefore, new N and P fertilizer recommendations are needed for microsprinkler-irrigated citrus. The objectives of these experiments were to i) determine the effects of N applications on tree growth, fruit yield, fruit and juice quality, and N and P removal in fruit for microsprinkler-irrigated

Thomas L. Thompson; Scott A. White

377

Light effect on carotenoids production and expression of carotenogenesis genes in citrus callus of four genotypes  

Microsoft Academic Search

Due to their theoretically identical genetic background, citrus callus and other plant tissues may share some mechanisms in\\u000a the regulation of carotenogenesis. Thus, in order to gain further information on light regulation of carotenoids biosynthesis\\u000a in citrus, the carotenoids and expression profiles of carotenogenesis in calluses of four citrus genotypes treated with light\\u000a or dark were investigated. As a response

Huijun GaoJuan; Juan Xu; Xi Liu; Baozhen Liu; Xiuxin Deng

378

Laboratory evaluation of the effectiveness of the entomopathogen; Isaria farinosa, on citrus mealybug, Planococcus citri  

Microsoft Academic Search

Citrus mealybug Planococcus citri (Risso) (Hemiptera: Pseudococcidae) is one of the main pests on citrus trees. Biological control of the pest is based on\\u000a the release of hymenopterous parasitoids and coccinellid predators at present. The effectiveness of entomopathogen fungus\\u000a Isaria farinosa (Holmsk.) Fries ([Sordariomycetes: Hypocreales] (Syn: Paecilomyces farinosus), as an alternative biological control agent on citrus mealybug, was investigated using

Fikret Demirci; Murat Mu?tu; M. Bora Kaydan; Selma Ülgentürk

379

Identification and characterization of 27 conserved microRNAs in citrus.  

PubMed

MicroRNAs (miRNAs) are a class of non-protein-coding small RNAs. Considering the conservation of many miRNA genes in different plant genomes, the identification of miRNAs from non-model organisms is both practicable and instrumental in addressing miRNA-guided gene regulation. Citrus is an important staple fruit tree, and publicly available expressed sequence tag (EST) database for citrus are increasing. However, until now, little has been known about miRNA in citrus. In this study, 27 known miRNAs from Arabidopsis were searched against citrus EST databases for miRNA precursors, of which 13 searched precursor sequences could form fold-back structures similar with those of Arabidopsis. The ubiquitous expression of those 13 citrus microRNAs and other 13 potential citrus miRNAs could be detected in citrus leaf, young shoot, flower, fruit and root by northern blotting, and some of them showed differential expression in different tissues. Based on the fact that miRNAs exhibit perfect or nearly perfect complementarity with their target sequences, a total of 41 potential targets were identified for 15 citrus miRNAs. The majority of the targets are transcription factors that play important roles in citrus development, including leaf, shoot, and root development. Additionally, some other target genes appear to play roles in diverse physiological processes. Four target genes have been experimentally verified by detection of the miRNA-mediated mRNA cleavage in Poncirus trifoliate. Overall, this study in the identification and characterization of miRNAs in citrus can initiate further study on citrus miRNA regulation mechanisms, and it can help us to know more about the important roles of miRNAs in citrus. PMID:19585144

Song, Changnian; Fang, Jinggui; Li, Xiaoying; Liu, Hong; Thomas Chao, C

2009-09-01

380

Variation in Radopholus citrophilus Population Densities in the Citrus Rootstock Carrizo Citrange.  

PubMed

Seedlings of the hybrid citrus rootstock, Carrizo citrange (Citrus sinensis x Poncirus trifoliata) do not uniformly limit development of the citrus burrowing nematode, Radopholus citrophilus. Variation in nematode population densities in roots of seedlings germinating from the same seed suggests that factors responsible for nematode incompatibility are not functional or are not inherited uniformly among progeny. Seeds which produced a single seedling were more likely to produce plants which suppressed citrus burrowing nematode population increase than were seeds which produced two or three seedlings. PMID:19294135

Kaplan, D T

1986-01-01

381

Stable Transformation of the Xylella fastidiosa Citrus Variegated Chlorosis Strain with oriC Plasmids  

PubMed Central

Xylella fastidiosa is a gram-negative, xylem-limited bacterium affecting economically important crops (e.g., grapevine, citrus, and coffee). The citrus variegated chlorosis (CVC) strain of X. fastidiosa is the causal agent of this severe disease of citrus in Brazil and represents the first plant-pathogenic bacterium for which the genome sequence was determined. Plasmids for the CVC strain of X. fastidiosa were constructed by combining the chromosomal replication origin (oriC) of X. fastidiosa with a gene which confers resistance to kanamycin (Kanr). In plasmid p16KdAori, the oriC fragment comprised the dnaA gene as well as the two flanking intergenic regions, whereas in plasmid p16Kori the oriC fragment was restricted to the dnaA-dnaN intergenic region, which contains dnaA-box like sequences and AT-rich clusters. In plasmid p16K, no oriC sequence was present. In the three constructs, the promoter region of one of the two X. fastidiosa rRNA operons was used to drive the transcription of the Kanr gene to optimize the expression of kanamycin resistance in X. fastidiosa. Five CVC X. fastidiosa strains, including strain 9a5c, the genome sequence of which was determined, and two strains isolated from coffee, were electroporated with plasmid p16KdAori or p16Kori. Two CVC isolates, strains J1a12 and B111, yielded kanamycin-resistant transformants when electroporated with plasmid p16KdAori or p16Kori but not when electroporated with p16K. Southern blot analyses of total DNA extracted from the transformants revealed that, in all clones tested, the plasmid had integrated into the host chromosome at the promoter region of the rRNA operon by homologous recombination. To our knowledge, this is the first report of stable transformation in X. fastidiosa. Integration of oriC plasmids into the X. fastidiosa chromosome by homologous recombination holds considerable promise for functional genomics by specific gene inactivation.

Monteiro, Patricia B.; Teixeira, Diva C.; Palma, Rene R.; Garnier, Monique; Bove, Joseph-Marie; Renaudin, Joel

2001-01-01

382

Characterization of the odor-active volatiles in citrus Hyuganatsu (Citrus tamurana Hort. ex Tanaka).  

PubMed

The volatile components of Hyuganatsu (Citrus tamurana Hort. ex Tanaka) peel oil, isolated by cold-pressing, were investigated by chemical and sensory analyses. According to chemical analysis by GC and GC-MS, limonene (84.0%) was the most abundant compound, followed by gamma-terpinene (6.9%), myrcene (2.2%), alpha-pinene (1.2%), and linalool (1.0%). Monoterpene hydrocarbons were predominant in Hyuganatsu peel oil. The odor-active volatiles in Hyuganatsu flavor were studied by GC-olfactometry and omission tests. The characteristic flavor was present in the oxygenated fraction. Flavor dilution (FD) factors of the volatile flavor components of the Hyuganatsu cold-pressed oil were determined by aroma extraction dilution analysis (AEDA). Furthermore, relative flavor activity was investigated by means of FD factor and weight percent. Ten kinds of odor compounds having Hyuganatsu-like aroma were detected by AEDA: limonene, linalool, octanol, neral, neryl acetate, tridecanal, trans-carveol, cis-nerolidol, trans,trans-farnesyl acetate, and trans,trans-farnesol. Linalool and octanol were regarded as the most odor-active or key compounds of Hyuganatsu aroma. Diluted solutions of linalool and octanol of approximately 2 ppm gave a fresh and fruity aroma note similar to Hyuganatsu flavor. PMID:11368611

Choi, H S; Kondo, Y; Sawamura, M

2001-05-01

383

Identification and expression analysis of cold-regulated genes from the cold-hardy Citrus relative Poncirus trifoliata (L.) Raf  

Microsoft Academic Search

Citrus is a cold-sensitive genus and most commercially important varieties of citrus are susceptible to freezes. On the other hand, Poncirus trifoliata (L.) Raf. is an interfertile Citrus relative that can tolerate temperatures as low as ?26C when fully cold acclimated. Therefore, it has been used for improving cold tolerance in cold-sensitive commercial citrus rootstock varieties and in attempts to

Gloria A. Moore

2006-01-01

384

Volatile composition of hybrids Citrus juices by headspace solid-phase micro extraction\\/gas chromatography\\/mass spectrometry  

Microsoft Academic Search

The volatile compounds of Citrus juices have been extracted by headspace solid-phase microextraction (HS-SPME) and analysed by gas chromatography (GC) and gas chromatography\\/mass spectrometry (GC\\/MS). This work deals with the analysis of 65 cross pollinated hybrid fruits and their parents: mandarin (Citrus reticulata Blanco var. Willow Leaf) and clementine (Citrus reticulata×Citrus sinensis var. Commune). Among the 44 components identified which

Toussaint Barboni; François Luro; Nathalie Chiaramonti; Jean-Marie Desjobert; Alain Muselli; Jean Costa

2009-01-01

385

Some predaceous mites [ Phytoseiidae ] on citrus in the mediterranean region  

Microsoft Academic Search

Seven species of phytoseiid mites were collected from citrus trees in the Mediterranean region during a survey in 1971.Amblyseius stipulatus\\u000a Athias-Henriot was the most abundant and widespread species in all countries surveyed (Turkey, Greece, Italy, Spain).A. californicus (McGregor) was collected only in Spain;A. potentillae (Garman) andPhytoseiulus persimilis. A.-H. only in Italy.Typhlodromus talbii A.-H. was collected in Greece and Spain,T. athiasae

J. A. McMurtry

1977-01-01

386

Influence of mitochondria on gene expression in a citrus cybrid  

Microsoft Academic Search

The production of cybrids, combining nucleus of a species with alien cytoplasmic organelles, is a valuable method used for\\u000a improvement of various crops. Several citrus cybrids have been created by somatic hybridization. These genotypes are interesting\\u000a models to analyze the impact of cytoplasmic genome change on nuclear genome expression. Herein, we report genome-wide gene\\u000a expression analysis in leaves of a

Jean-Baptiste Bassene; Yann Froelicher; Luis Navarro; Patrick Ollitrault; Gema Ancillo

2011-01-01

387

Biochemical Markers and Nutrient Constraints Diagnosis in Citrus: A Perspective  

Microsoft Academic Search

Mineral deficiencies are well-established causal factor(s) for sub-optimum production in citrus. Identifying nutrient constraints based on morphological symptoms or in combination with leaf\\/soil analysis is often misleading, especially with reference to remediating the nutritional problems of a standing crop. The task becomes further confounded by other co-factors under the conditions favoring the occurrence of multi-nutrient deficiency. Important biochemical markers for

A. K. Srivastava; Shyam Singh

2006-01-01

388

Inhibitory effects of citrus extracts on the experimental pulmonary fibrosis  

Microsoft Academic Search

Aim of the studyA Chinese herbal formula, Hu-qi-yin possessed an anti-pulmonary fibrosis effect. Pericarp of Citrus reticulata, one of the herbal drugs contained in this formula showed the most potent inhibitory activity on the proliferation of human embryonic lung fibroblasts (HELF). The present study was designed to clarify the active principles responsible for the activity and further explore the anti-pulmonary

Xian-Mei Zhou; Min-Min Huang; Cui-Cui He; Jian-Xin Li

2009-01-01

389

Dicofol exposure to Florida citrus applicators: Effects of protective clothing  

Microsoft Academic Search

Mixer-loaders and applicators of the pesticide dicofol in Florida citrus groves were monitored for exposure. Alpha-cellulose pads were placed inside and outside regular work clothing. When protective suits were in use, pads were also placed outside the suit. Dicofol accumulation rates were measured when gloves and\\/or facemasks were worn. Hand rinses were collected. Results showed that an ungloved, normally attired

H. N. Nigg; J. H. Stamper; R. M. Queen

1986-01-01

390

A new limonoid from the seeds of Citrus reticulata Blanco.  

PubMed

A new limonoid, named Citriolide-A (1), along with the known structurally related compounds 2-5, was isolated from the liposoluble extract of the seeds of Citrus reticulata Blanco. The structure of Citriolide-A (1) was elucidated by means of EI, 1D- and 2D-NMR techniques. Compounds 1, 2 and 4 exhibited medium cytotoxicity against P-388 and A-549 cell lines. PMID:21834637

Liao, Jun; Xu, Teng; Liu, Yun-Hai; Wang, Shi-Zhong

2012-01-01

391

Gibberellin-ethylene interaction controls radial expansion in citrus roots  

Microsoft Academic Search

.   The involvement of gibberellins (GAs) and ethylene in the process of root radial expansion was studied in young seedlings\\u000a of Carrizo citrange [Citrus sinensis (L.) Osb.?×?Poncirus trifoliata (L.) Raf.]. The GA inhibitors cycocel, paclobutrazol, and tetcyclacis enhanced radial expansion of the root tip (up to 2.3-fold)\\u000a as a result of increases in stele diameter and inner cortex width. The

F. R. Tadeo; A. Gómez-Cadenas; W. Ben-Cheikh; E. Primo-Millo; M. Talón

1997-01-01

392

Sugar regulation of plastid interconversions in epicarp of citrus fruit.  

PubMed

Seasonal transformations between chloroplasts and chromoplasts, as measured by changes in chlorophyll content, in the epicarp of degreening and regreening Citrus sinensis (L.) Osbeck cv Valencia fruit closely parallelled the accumulation and later loss of soluble sugars. At any stage of development, reversing the relative soluble sugar content in the epicarp by culturing pericarp segments on agar media with low (15 millimolar) or high (150 millimolar) sucrose concentrations reversed the direction of change in chlorophyll content. Fruit of C. madurensis Lour., which mature year around and do not regreen, also accumulated soluble sugars in the pericarp as degreening was initiated.The epicarp of C. sinensis fruit accumulated nitrogen, but total nitrogen concentrations and amino acid concentrations changed little, during degreening and regreening of C. sinensis fruit. Cessation of nitrogen fertilization reduced the tendency of pericarp segments to regreen in vitro during subsequent years, but regreening tendency was restored by inclusion of KNO(3) in the media.It is concluded that chloroplasts become chromoplasts and citrus fruit degreen partially in response to the accumulation of sugars in the epicarp and that the reverse transformation accompanying regreening of certain citrus species occurs when accumulated sugars disappear. Change in nitrogen flux to the fruit is probably not a factor in regulating seasonal transformations, but an abundance of nitrogen in the epicarp diminishes the effects of high sugar concentrations in inducing transformation of chloroplasts to chromoplasts, thereby retarding degreening and promoting regreening. PMID:16663837

Huff, A

1984-10-01

393

Induction of triploid Citrus plants from endosperm calli in vitro.  

PubMed

Triploid hybrid Citrus plants were regenerated by somatic embryogenesis in vitro from endosperm derived calli. A sequence of media formulations was used to induce and support proliferation of primary callus from endosperm, to induce embryogenesis from primary callus, and to allow embryo development leading to viable plantlets. Calli were induced from cellular endosperm of Citrus sinensis (sweet orange), C. Xparadisi (grapefruit), and C. grandis (pummelo) excised 12-14 weeks post-anthesis. Induction of embryogenesis from sweet orange and pummelo primary calli required gibberellic acid and double mineral nutrient concentrations. Embryogenesis was not induced from grapefruit calli in these experiments. Only sweet orange embryos developed sufficiently to allow plant regeneration. Triploid axillary buds were minigrafted onto etiolated diploid rootstock seedlings in vitro in order to transfer triploid regenerants to soil and the external environment. Triploidy (2n = 3x = 27) was observed consistently in all phases of regeneration and in recovered plants. These results demonstrate that triploid hybrid plant recovery from Citrus endosperm can overcome barriers to sexual hybridization resulting from apomixis. PMID:24221109

Gmitter, F G; Ling, X B; Deng, X X

1990-12-01

394

Autoinhibition of Ethylene Production in Citrus Peel Discs 1  

PubMed Central

Wound ethylene formation induced in flavede tissue of citrus fruit (Citrus paradisi MacFad. cv. Ruby Red) by slicing was almost completely inhibited by exogenous ethylene. The inhibition lasted for at least 6 hours after removal of exogenous ethylene and was then gradually relieved. The extent of inhibition was dependent upon the concentration of ethylene (1 to 10 microliters/liter) and the duration of treatment. The increase in wound ethylene production in control discs was paralleled by an increase in 1-aminocyclopropane-1-carboxylic acid (AAC) content, whereas in ethylene-treated discs there was little increase in ACC content. Application of ACC completely restored ethylene production in ethylene-pretreated discs, indicating that the conversion of ACC to ethylene is not impaired by the presence of ethylene. Thus, autoinhibition of ethylene synthesis was exerted by reducing the availability of ACC. Ethylene treatment resulted in a decrease in extractable ACC synthase activity, but this decrease was too small to account for the marked inhibition of ACC formation. The data indicate that autoinhibition of ethylene production in citrus flavede discs results from suppression of ACC formation through repression of the synthesis of ACC synthase and inhibition of its activity.

Riov, Joseph; Yang, Shang Fa

1982-01-01

395

Florida Citrus Freezes and Polar Anticyclones in the Great Plains.  

NASA Astrophysics Data System (ADS)

Severe Florida citrus freezes since 1880 are identified and described in terms of the horticultural damage, overall frequency of occurrence, and association with polar anticyclone outbreaks in the plains of southern Canada and the United States. The most severe `advective' freezes are associated with strong cold anticyclones having tracks southward across the plains to Texas with subsequent northeastward movement. Other anticyclones move in a track somewhat east of this and ultimately pass over Florida or the eastern Gulf of Mexico. Over 80% of the worst Florida citrus freezes are associated with anticyclones with central pressures in excess of 1045 mb moving along these paths. However, anticyclones of similar intensity with more zonally oriented paths across higher latitudes are associated with minor citrus damage. The major freezes tend to be clustered in time in the 1890s and since 1977. On interdecadal time scales, the recent freezes are not linked to higher winter mean pressure in the northern plains, and there has not been an unusually high frequency of strong anticyclones in recent decades, compared to earlier this century. Compared to the freeze-free period of 1948-57, the winters of 1977-86 are characterized by a more amplified 500-mb mean standing wave pattern across North America. This is linked to changes in the Pacific/North American upper-air teleconnection pattern, the index for which had much lower values (characterized by zonal flow) prior to 1958.

Rogers, Jeffrey C.; Rohli, Robert V.

1991-11-01

396

Changes in Peroxidase Activity in the Peel of Unshiu Mandarin (Citrus unshiu Marc.) Fruit with Different Storage Treatments  

Microsoft Academic Search

Summary The Unshiu mandarin (Citrus unshiu Marc.) is the major Citrus crop in Croatia. Limit- ing factors for longer consumption of Unshiu mandarin are low storage performance and the appearance of chilling injuries during storage. Previous studies indicated that oxida- tive stress might be involved in cold-induced peel damage of harvested Citrus fruit. The aim of the present study was

Hrvoje Lepedu; Marko Jozi; Nikola Pavi; Branimir K. Hackenberger; Vera Cesar

2005-01-01

397

A multiplex polymerase chain reaction method for reliable, sensitive and simultaneous detection of multiple viruses in citrus trees.  

PubMed

A multiplex polymerase chain reaction (mPCR) assay was developed to detect six RNA and one DNA citrus virus: Citrus leaf rugose virus (CLRV), Citrus psorosis virus (CPsV), Citrus tatter leaf virus (CTLV), Citrus tristeza virus (CTV), Citrus variegation virus (CVV), Citrus yellow mosaic virus (CYMV), and Indian citrus ringspot virus (ICRSV) from citrus plants. These seven viruses are classified in six different virus genera. Degenerate primers were designed based on the respective virus isolate sequence data available from the GenBank and were used for reliable detection of the different viruses by simplex- and mPCR. The sensitive and simultaneous detection of RNA and DNA viruses using the mPCR decreases the risk of contamination, saves time and reduces the cost as compared to other conventional methods for citrus virus detection. Seven different fragments (245-942 bp) specific to the viruses were simultaneously amplified using mPCR and were identified on the basis of their molecular sizes. The consistent results of the mPCR were compared with simplex PCR for detection of each virus pathogen. The mPCR results were confirmed with sequencing analysis. The mPCR provides a useful rapid method for detecting multiple viruses in citrus plants that will aid in the production of virus-free citrus plants for certification programs. PMID:15951030

Roy, Avijit; Fayad, Amer; Barthe, G; Brlansky, R H

2005-10-01

398

Colonization of citrus seed coats by 'Candidatus Liberibacter asiaticus': implications for seed transmission of the bacterium.  

PubMed

Huanglongbing is an economically damaging disease of citrus associated with infection by 'Candidatus Liberibacter asiaticus'. Transmission of the organism via infection of seeds has not been demonstrated but is a concern since some citrus varieties, particularly those used as rootstocks in commercial plantings are propagated from seed. We compared the incidence of detection of 'Ca. Liberibacter asiaticus' DNA in individual fruit peduncles, seed coats, seeds, and in germinated seedlings from 'Sanguenelli' sweet orange and 'Conners' grapefruit fruits sampled from infected trees. Using real-time quantitative PCR (qPCR) we detected pathogen DNA in nucleic acid extracts of 36 and 100% of peduncles from 'Sanguenelli' and from 'Conners' fruits, respectively. We also detected pathogen DNA in extracts of 37 and 98% of seed coats and in 1.6 and 4% of extracts from the corresponding seeds of 'Sanguenelli' and 'Conners', respectively. Small amounts of pathogen DNA were detected in 10% of 'Sanguenelli' seedlings grown in the greenhouse, but in none of 204 extracts from 'Conners' seedlings. Pathogen DNA was detected in 4.9% and in 89% of seed coats peeled from seeds of 'Sanguenelli' and 'Conners' which were germinated on agar, and in 5% of 'Sanguenelli' but in none of 164 'Conners' seedlings which grew from these seeds on agar. No pathogen DNA was detected in 'Ridge Pineapple' tissue at 3 months post-grafting onto 'Sanguenelli' seedlings, even when pathogen DNA had been detected initially in the 'Sanguenelli' seedling. Though the apparent colonization of 'Conners' seeds was more extensive and nearly uniform compared with 'Sanguenelli' seeds, no pathogen DNA was detected in 'Conners' seedlings grown from these seeds. For either variety, no association was established between the presence of pathogen DNA in fruit peduncles and seed coats and in seedlings. PMID:21714779

Hilf, Mark E

2011-10-01

399

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

Microsoft Academic Search

The prevalence of sour orange rootstock in the southern and eastern part of the Mediterranean Basin is presently threatened\\u000a by the spread of Citrus Tristeza Virus (CTV) and its main vector Toxoptera citricida, combined with abiotic constraints such as drought, salinity and alkalinity. The search for alternative CTV-resistant rootstocks\\u000a that also withstand the other constraints is now considered an urgent

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

2011-01-01

400

Delineating productivity zones in a citrus grove using citrus production, tree growth and temporally stable soil data  

Microsoft Academic Search

The productivity of a citrus grove with variation in tree growth was mapped to delineate zones of productivity based on several\\u000a indicator properties. These properties were fruit yield, ultrasonically measured tree canopy volume, normalized difference\\u000a vegetation index (NDVI), elevation and apparent electrical conductivity (ECa). The spatial patterns of soil series, soil color and ECa, and their correspondence with the variation

K. K. MannA; A. W. Schumann; T. A. Obreza

2011-01-01

401

Deciphering the bacterial microbiome of citrus plants in response to 'Candidatus Liberibacter asiaticus'-infection and antibiotic treatments.  

PubMed

The bacterial microbiomes of citrus plants were characterized in response to 'Candidatus Liberibacter asiaticus' (Las)-infection and treatments with ampicillin (Amp) and gentamicin (Gm) by Phylochip-based metagenomics. The results revealed that 7,407 of over 50,000 known Operational Taxonomic Units (OTUs) in 53 phyla were detected in citrus leaf midribs using the PhyloChip™ G3 array, of which five phyla were dominant, Proteobacteria (38.7%), Firmicutes (29.0%), Actinobacteria (16.1%), Bacteroidetes (6.2%) and Cyanobacteria (2.3%). The OTU62806, representing 'Candidatus Liberibacter', was present with a high titer in the plants graft-inoculated with Las-infected scions treated with Gm at 100 mg/L and in the water-treated control (CK1). However, the Las bacterium was not detected in the plants graft-inoculated with Las-infected scions treated with Amp at 1.0 g/L or in plants graft-inoculated with Las-free scions (CK2). The PhyloChip array demonstrated that more OTUs, at a higher abundance, were detected in the Gm-treated plants than in the other treatment and the controls. Pairwise comparisons indicated that 23 OTUs from the Achromobacter spp. and 12 OTUs from the Methylobacterium spp. were more abundant in CK2 and CK1, respectively. Ten abundant OTUs from the Stenotrophomonas spp. were detected only in the Amp-treatment. These results provide new insights into microbial communities that may be associated with the progression of citrus huanglongbing (HLB) and the potential effects of antibiotics on the disease and microbial ecology. PMID:24250784

Zhang, Muqing; Powell, Charles A; Benyon, Lesley S; Zhou, Hui; Duan, Yongping

2013-01-01

402

Deciphering the Bacterial Microbiome of Citrus Plants in Response to 'Candidatus Liberibacter asiaticus'-Infection and Antibiotic Treatments  

PubMed Central

The bacterial microbiomes of citrus plants were characterized in response to ‘Candidatus Liberibacter asiaticus’ (Las)-infection and treatments with ampicillin (Amp) and gentamicin (Gm) by Phylochip-based metagenomics. The results revealed that 7,407 of over 50,000 known Operational Taxonomic Units (OTUs) in 53 phyla were detected in citrus leaf midribs using the PhyloChip™ G3 array, of which five phyla were dominant, Proteobacteria (38.7%), Firmicutes (29.0%), Actinobacteria (16.1%), Bacteroidetes (6.2%) and Cyanobacteria (2.3%). The OTU62806, representing ‘Candidatus Liberibacter’, was present with a high titer in the plants graft-inoculated with Las-infected scions treated with Gm at 100 mg/L and in the water-treated control (CK1). However, the Las bacterium was not detected in the plants graft-inoculated with Las-infected scions treated with Amp at 1.0 g/L or in plants graft-inoculated with Las-free scions (CK2). The PhyloChip array demonstrated that more OTUs, at a higher abundance, were detected in the Gm-treated plants than in the other treatment and the controls. Pairwise comparisons indicated that 23 OTUs from the Achromobacter spp. and 12 OTUs from the Methylobacterium spp. were more abundant in CK2 and CK1, respectively. Ten abundant OTUs from the Stenotrophomonas spp. were detected only in the Amp-treatment. These results provide new insights into microbial communities that may be associated with the progression of citrus huanglongbing (HLB) and the potential effects of antibiotics on the disease and microbial ecology.

Zhang, Muqing; Powell, Charles A.; Benyon, Lesley S.; Zhou, Hui; Duan, Yongping

2013-01-01

403

Replacement of CTV-susceptible sour orange rootstock by CTV-tolerant ones may have triggered outbreaks of Tetranychus urticae in Spanish citrus  

Microsoft Academic Search

The two spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) is a major pest of citrus in Spain. Commercial citrus plants are always propagated asexually by bud-grafting onto a seedling rootstock. During the last 70 years, millions of citrus trees grafted on sour orange have been destroyed because of Citrus tristeza virus (CTV). Therefore other rootstocks are nowadays predominant. The

Friederike Bruessow; María J. Asins; Josep A. Jacas; Alberto Urbaneja

2010-01-01

404

Influence of Fusarium solani on citrus root rot caused by Phytophthora parasitica and Phytophthora citrophthora  

Microsoft Academic Search

Interactions between Fusarium solani and Phytophthora parasitica or F. solani and P. citrophthora influenced the development of root rot of citrus but depended on the temporal order of inoculation with F. solani or the two Phytophthora spp. Inoculation of citrus with either Fusarium solani and Phytophthora parasitica or Phytophthora citrophthora increased root rot compared to inoculation with P. parasitica or

L. M. Dandurand; J. A. Menge

1992-01-01

405

Attractiveness of Citrus Pulp and Orange Albedo Extracts to Atta sexdens rubropilosa (Hymenoptera: Formicidae)  

Microsoft Academic Search

The present study aimed to compare the attractiveness of industrial citrus pulp with the handmade orange albedo to the workers of Atta sexdens rubro- pilosa. For this, filter paper fragments were impregnated with organic extracts obtained through chemical extraction and sequential fractioning with hexane and dichloromethane and offered to different field nests. It was verified that the industrial citrus pulp

Sandra S. Verza; Luiz C. Forti; Carlos A. O. Matos; Marise G. Garcia; Nilson S. Nagamoto

406

A genome-wide 20 K citrus microarray for gene expression analysis  

Microsoft Academic Search

BACKGROUND: Understanding of genetic elements that contribute to key aspects of citrus biology will impact future improvements in this economically important crop. Global gene expression analysis demands microarray platforms with a high genome coverage. In the last years, genome-wide EST collections have been generated in citrus, opening the possibility to create new tools for functional genomics in this crop plant.

M Angeles Martinez-Godoy; Nuria Mauri; Jose Juarez; M Carmen Marques; Julia Santiago; Javier Forment; Jose Gadea

2008-01-01

407

A localized linkage map of the citrus tristeza virus resistance gene region  

Microsoft Academic Search

A localized genetic linkage map was developed of the region surrounding the citrus tristeza virus (CTV) resistance gene (designated Ctv) from Poncirus trifoliate L., a sexually compatible Citrus relative. Bulked segregant analysis (BSA) was used to identify potential resistance-associated RAPD fragment markers in four intergeneric backcross families that were segregating for CTV resistance. Eight RAPD fragments were found that were

F. G. Gmitter Jr; S. Y. Xiao; S. Huang; X. L. Hu; S. M. Garnsey; Z. Deng

1996-01-01

408

Valorization of citrus by-products using Microwave Steam Distillation (MSD)  

Microsoft Academic Search

A microwave steam distillation (MSD) of essential oils from fresh citrus by-products (orange peels) was studied. The effectiveness of this innovative method in extraction of citrus essential oils have been evaluated and compared to conventional steam distillation. MSD offers important advantages like shorter extraction time (6min), cleaner features and provides an essential oil with better sensory properties (better reproduction of

Naima Sahraoui; Maryline Abert Vian; Mohamed El Maataoui; Chahrazed Boutekedjiret; Farid Chemat

2011-01-01

409

Gynogenetic haploids of Citrus after in vitro pollination with triploid pollen grains  

Microsoft Academic Search

This study reports haploid plantlet regeneration through gynogenesis in Citrus clementina Hort. ex Tan., cv. Nules, induced by in vitro pollination with pollen grains of Oroblanco, a triploid cultivar of grapefruit. It indicates that parthenogenesis induced\\u000a in vitro by triploid pollen can be an alternative method to obtain haploids in monoembryonic cultivars of Citrus. Actually, despite considerable efforts, androgenesis has

M. A. Germanà; B. Chiancone

2001-01-01

410

A PRELIMINARY ANALYSIS ON FINANCIAL ASSESSMENT OF CITRUS HYSTRIX (LIMAU PURUT) GROWN ON PLANTATION BASIS  

Microsoft Academic Search

A study was conducted to assess the financial viability of Citrus hystrix (limau purut) on a plantation scale. Citrus hystrix are being well planted by the farmers and plantation managers. However, little information is available on the financial assessment of the species. The study was conducted using secondary data and data gathered from the establishment of a clone bank located

M. A. Farah Fazwa; P. Ahmad Fauzi; A. G. Ab; M. Mohd Noor; Selangor Darul Ehsan

411

Pesticides and plasticizers in Citrus essential oils: An ordinary history of research  

Microsoft Academic Search

The history of the research on pesticides and plasticizers presence in Citrus essential oils is resumed. The determinations of organophosphorus pesticides, organochlorine pesticides, and some class of plasticizers (triarylphosphates, phthalate esters, chloroparaffins, adipate esters, sebacate esters) are described, and the evolution of the contamination over the years and according to the type of Citrus essential oil is highlighted.

Marcello Saitta; Giuseppa Di Bella; Giacomo Dugo

2012-01-01

412

From Bitter Fruit a Sweet Weight-Loss Supplement Beyond Ephedra: Bitter Orange (Citrus Aurantium)  

Microsoft Academic Search

Though displaced by tastier varieties, researchers have shown great interest in the lowly bitter orange after recently discovering that Citrus aurantium contains a number of natural alkaloids that safely increase weight loss. Best of all, Citrus aurantium does so without many of the negative side effects to the cardiovascular and central nervous systems commonly experienced with weight-control agents such as

Jim English

413

7 CFR 905.149 - Procedure for permitting growers to ship tree run citrus fruit.  

...false Procedure for permitting growers to ship tree run citrus fruit. 905.149 Section...149 Procedure for permitting growers to ship tree run citrus fruit. (a) Tree run...Application. A grower shall apply to ship tree run fruit using a Grower...

2014-01-01

414

Pharmacokinetics of the citrus flavanone aglycones hesperetin and naringenin after single oral administration in human subjects  

Microsoft Academic Search

Background and objective:Hesperetin and naringenin, the aglycones of the flavanone glycosides hesperidin and naringin, occur naturally in citrus fruits. They exert interesting pharmacological properties such as antioxidant, anti-inflammatory, blood lipid and cholesterol lowering and are considered to contribute to health benefits in humans. However, no information is available on the pharmacokinetics of the citrus flavanones hesperetin and naringenin after their

F I Kanaze; M I Bounartzi; M Georgarakis; I Niopas

2007-01-01

415

Production costs of citrus growing in the Comunidad Valenciana (Spain): EUREPGAP protocol versus standard production  

Microsoft Academic Search

The first aim of this paper is to analyse the average production costs of citrus cultivated under EUREPGAP protocol regulation in the Comunidad Valenciana (Spain). To this end, we shall study a sample of plots administered under the same management, specifically a citrus cooperative located in one of the most important production areas of the region. The results obtained shall

Elena M; Peris Moll

416

Larval Cryptothelea gloverii (Lepidoptera: Psycidae), an arthropod predator and herbivore on Florida citrus  

Microsoft Academic Search

The orange bagworm (OBW), Cryptothelea gloverii (Packard) (Lepidoptera: Psychidae) was previously reported feeding on citrus fruit and foliage and preying upon the camphor scale Pseudaonidia duplex (Cockerell) (Homoptera: Coccidae). In this study using laboratory assays, OBW preyed upon citrus rust mite, Phyllocoptruta oleivora (Ashmead) (Acari: Eriophyidae) and consumed eggs and adults of both P. oleivora and Panonychus citri (McGregor) (Acari:

Raul T. Villanueva; Jose C. V. Rodrigues; Carl C. Childers

2005-01-01

417

Acetolactate Synthase Inhibitors Increase Ethylene Production and Cause Fruit Drop in Citrus  

Microsoft Academic Search

The abscission action of two sulfonylureas and one imidazolinone was evaluated in laboratory studies with harvested orange ( Citrus sinensis L. cv. Valencia) fruit and greenhouse studies with orange (cv. Hamlin) and grapefruit ( Citrus paradisi Macf. cv. Marsh) trees. Dipping harvested fruit in 90 mg·L -1 imazameth, 2 mg·L -1 metsulfuron- methyl, or 30 mg·L -1 prosulfuron solutions increased

Jacqueline K. Burns; Ulrich Hartmond; Walter J. Kender

418

An improved HPLC method for the analysis of citrus limonoids in culture media  

Microsoft Academic Search

Recent studies have shown that citrus limonoids have potential health benefits. However, information on the absorption and metabolism of limonoids in human gastrointestinal (GI) tract is limited. In the present study we have investigated the metabolism of limonin glucoside (LG), the predominant limonoid in citrus by four microorganisms (Enterococcus fecalis, Escherichia coli, Lactobacillus salivarius, and Candida albican) widely present in

Qingguo Tian; Edward G. Miller; G. K. Jayaprakasha; Bhimanagouda S. Patil

2007-01-01

419

SOIL AND DIAPREPES ABBREVIATUS ROOT WEEVIL SPATIAL VARIABILITY IN A POORLY DRAINED CITRUS GROVE  

Microsoft Academic Search

Soil and water variability in space and time could be important for management of the citrus root weevil, Diaprepes abbreviatus (L.). We con- ducted a study of soil, tree, and root weevil relationships in a poorly drained grove of Hamlin orange on Swingle citrumelo rootstock (Pon- cirus trifoliata (L.) Raf. X Citrus paradisi Macfad.) in central Florida in 2002. We

Hong Li; James P. Syvertsen; Robin J. Stuart; Clay W. McCoy; Arnold W. Schumann; William S. Castle

2004-01-01

420

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

PubMed

Citrus is an economically important fruit crop that is severely afflicted by Asiatic citrus bacterial canker (CBC), a disease caused by the phytopathogen Xanthomonas citri subsp. citri (X. citri). To gain insight into the molecular epidemiology of CBC, 42 Xanthomonas isolates were collected from a range of Citrus spp. across 17 different orchards in Tucumán, Argentina and subjected to molecular, biochemical, and pathogenicity tests. Analysis of genome-specific X. citri markers and DNA polymorphisms based on repetitive elements-based polymerase chain reaction showed that all 42 isolates belonged to X. citri. Interestingly, pathogenicity tests showed that one isolate, which shares >90% genetic similarity to the reference strain X. citri T, has host range specificity. This new variant of X. citri subsp. citri, named X. citri A(T), which is deficient in xanthan production, induces an atypical, noncankerous chlorotic phenotype in Citrus limon and C. paradisi and weak cankerous lesions in C. aurantifolia and C. clementina leaves. In C. limon, suppression of canker development is concomitant with an oxidative burst; xanthan is not implicated in the phenotype induced by this interaction, suggesting that other bacterial factors would be involved in triggering the defense response. PMID:23268580

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

2013-06-01

421

Non-Host Defense Response in a Novel Arabidopsis-Xanthomonas citri subsp. citri Pathosystem  

PubMed Central

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

An, Chuanfu; Mou, Zhonglin

2012-01-01

422

Proteomic analysis of resistance mediated by Rcm 2.0 and Rcm 5.1, two loci controlling resistance to bacterial canker of tomato.  

PubMed

Two quantitative trait loci from Lycopersicon hirsutum, Rcm 2.0 and Rcm 5.1, control resistance to Clavibacter michiganensis subsp. michiganensis, the causal agent of bacterial canker of tomato. Lines containing Rcm 2.0 and Rcm 5.1 and a susceptible control line were compared at 72 and 144 h postinoculation, using 2-dimensional gel electrophoresis to identify proteins regulated in response to C. michiganensis subsp. michiganensis infection. A total of 47 proteins were subjected to tandem mass spectrometry. Database queries with resulting spectra identified tomato genes for 26 proteins. The remaining 21 proteins were either identified in other species or possessed no homology to known proteins. Spectra were interpreted to deduce peptide amino acid sequences that were then used to query publicly available data. This approach identified tomato genes or expressed sequence tags for 44 of the proteins analyzed. Three superoxide dismutase (SOD) enzymes were differentially regulated among genotypes, and patterns of hydrogen peroxide accumulation were genotype- and tissue-specific, indicating a role for oxidative stress in response to C. michiganensis subsp. michiganensis. Steady-state mRNA and protein levels for SOD, thioredoxin M-type, S-adenosylhomocysteine hydrolase, and pathogenesis-related proteins demonstrated similar patterns of differential regulation. Lines containing Rcm 2.0 and Rcm 5.1 accumulate different proteins and steady-state mRNAs in response to inoculation, suggesting that the two loci may confer resistance through distinct mechanisms. PMID:15384492

Coaker, Gitta L; Willard, Belinda; Kinter, Michael; Stockinger, Eric J; Francis, David M

2004-09-01

423

Structure-activity relationship of citrus polymethoxylated flavones and their inhibitory effects on Aspergillus niger.  

PubMed

Citrus peels are rich in polymethoxylated flavones (PMFs) and are potential sources of natural preservatives. Six PMFs extracts, isolated and purified from the peels of three mandarins (Citrus reticulata) and three sweet oranges (Citrus sinensis), were identified and quantitated. Their inhibitory effects on Aspergillus niger were evaluated using a microbroth dilution assay. The Red tangerine variety exhibited the greatest antifungal activity (MIC = 0.2 mg/mL), while Jincheng showed the lowest activity (MIC = 1.8 mg/mL). An analysis of principal components was applied to the results in order to elucidate the structure-activity relationships of the citrus PMFs. The structure-activity relationship analysis revealed that, for good inhibitory effect, the 5-OH, 3-OCH?, and 8-OCH? functionalities were essential, while the presence of 3-OH and 3'-OCH? greatly reduced inhibition. The findings of this study provide important information for the exploitation and utilization of citrus PMFs as natural biopreservatives. PMID:22500738

Liu, Li; Xu, Xiaoyun; Cheng, Dan; Yao, Xiaolin; Pan, Siyi

2012-05-01

424