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Sample records for citrus postharvest diseases

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

    Science.gov (United States)

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

    2014-07-01

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

  2. Evaluation of alternatives to synthetic fungicides to control citrus postharvest diseases.

    OpenAIRE

    MONTESINOS HERRERO, CLARA ISABEL

    2016-01-01

    [EN] Citrus spp. (Rutaceae) are the most widely produced fruits and they are grown in over a hundred countries. During postharvest, major losses are caused by fungal diseases, that for decades have been controlled by treatments with synthetic fungicides. However, their use is continuously more restricted by distributors and supermarket chains, which lower the Maximum Residue Level (MRL) to one third of the authorized or even ban the use of certain fungicides. This has loss of efficacy of trea...

  3. Cercosporoid diseases of Citrus.

    Science.gov (United States)

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

    2015-01-01

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

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

    OpenAIRE

    Marcet-Houben Marina; Ballester Ana-Rosa; de la Fuente Beatriz; Harries Eleonora; Marcos Jose F; González-Candelas Luis; Gabaldón Toni

    2012-01-01

    Abstract Background Penicillium digitatum is a fungal necrotroph causing a common citrus postharvest disease known as green mold. In order to gain insight into the genetic bases of its virulence mechanisms and its high degree of host-specificity, the genomes of two P. digitatum strains that differ in their antifungal resistance traits have been sequenced and compared with those of 28 other Pezizomycotina. Results The two sequenced genomes are highly similar, but important differences between ...

  5. Cercosporoid diseases of Citrus

    NARCIS (Netherlands)

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

    2015-01-01

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

  6. Treatments with acetic acid followed by curing reduce postharvest decay on Citrus fruit.

    Science.gov (United States)

    Venditti, T; Angiolino, C; Dore, A; Molinu, M G; Petretto, A; D'Hallewin, G

    2009-01-01

    Citrus fruit are susceptible to many postharvest diseases and disorders, but Penicillium digitatum and Penicillium italicum are the most common and serious pathogens during storage and marketing. The continuous employ in packing houses of synthetic fungicides such as imazalil (IMZ) or thiabendazote for the control of these pathogens is promoting the selection of resistant biotypes. These considerations together with an increased attention for human health and the environment have multiplied the studies on new ecological technologies. In recent years researchers studies focused on alternatives to the chemical control of post-harvest decay, such as the utilization of GRAS compounds as well as physical methods. In the present study is reported the sequential use of acetic acid (AAC) followed by curing. The lemon variety "Verna" and the orange variety "Jaffa", naturally inoculated, were treated with vapours of AAC performed at three different concentration (15, 25 and 50 microL/L) for 15 minutes, after an incubation period of 24 hours at 27 degrees C and 90% relative humidity (RH). After treatments fruits were cured at 36 degrees C for 36 hours with 90% RH and subsequently stored at 8 degrees C and 90% of RH for eight weeks. Both citrus varieties were also treated with IMZ at a concentration of 200 mL/HL. At the end of the experiment decay and weight loss were evaluated. After 8 weeks of storage, in the lemon variety, the lowest percentage of infected wounds was 1.5% for both the fruit treated with IMZ or with AAC at 25 microL/L. Fruit treated with 15 mciroL/L or untreated (control) showed similar results with 13.6% and 16.6% of rotted fruit respectively. Different results were obtained with the orange variety, in this case the synthetic fungicide was the most effective at the end of the storage period, with 18.0% of decay. AAC treatments were not a successful as on lemons, the best result was achieved even in this case with AAC performed at 25 pL/L, but with 39.9% of

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

    Science.gov (United States)

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

  8. Citrus stubborn disease (CSD)

    Science.gov (United States)

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

  9. Salicylic acid treatment reduces the rot of postharvest citrus fruit by inducing the accumulation of H2O2, primary metabolites and lipophilic polymethoxylated flavones.

    Science.gov (United States)

    Zhu, Feng; Chen, Jiajing; Xiao, Xue; Zhang, Mingfei; Yun, Ze; Zeng, Yunliu; Xu, Juan; Cheng, Yunjiang; Deng, Xiuxin

    2016-09-15

    To comprehensively analyze the effects of salicylic acid (SA) on the storability of Satsuma mandarin (Citrus unshiu), fruits were treated with 2mM SA. The disease incidence of control/SA-treated fruit at 50d and 120d after treatment was 23.3%/10% and 67.3%/23.3%, respectively, suggesting that SA treatment can significantly reduce the rot rate of postharvest citrus fruit. Fruit quality assays revealed that the treatment can maintain fruit firmness without affecting the inner quality. Furthermore, the contents of H2O2 and some defense-related metabolites, such as ornithine and threonine, in citrus pericarp, were significantly increased by SA treatment. Moreover, it was lipophilic polymethoxylated flavones, rather than flavanone glycosides, that accumulated in SA-treated fruits and these can directly inhibit pathogen development. These results suggest that the effects of SA on postharvest citrus fruit may be attributed to the accumulation of H2O2 and defense-related metabolites. PMID:27080881

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

    Directory of Open Access Journals (Sweden)

    Marcet-Houben Marina

    2012-11-01

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

  11. Control of citrus postharvest green mold and sour rot by potassium sorbate combined with heat and fungicides

    Science.gov (United States)

    Potassium sorbate (KS), a common food preservative, was evaluated to control postharvest decay of citrus fruit. Significant advantages of KS over the commonly used sodium bicarbonate, which similarly improved fungicide performance, are the relatively low salt concentration of KS, the absence of sodi...

  12. Distinct Carotenoid and Flavonoid Accumulation in a Spontaneous Mutant of Ponkan (Citrus reticulata Blanco) Results in Yellowish Fruit and Enhanced Postharvest Resistance.

    Science.gov (United States)

    Luo, Tao; Xu, Kunyang; Luo, Yi; Chen, Jiajing; Sheng, Ling; Wang, Jinqiu; Han, Jingwen; Zeng, Yunliu; Xu, Juan; Chen, Jianmin; Wu, Qun; Cheng, Yunjiang; Deng, Xiuxin

    2015-09-30

    As the most important fresh fruit worldwide, citrus is often subjected to huge postharvest losses caused by abiotic and biotic stresses. As a promising strategy to reduce postharvest losses, enhancing natural defense by potential metabolism reprogramming in citrus mutants has rarely been reported. The yellowish spontaneous mutant of Ponkan (Citrus reticulata Blanco) (YP) was used to investigate the influence of metabolism reprogramming on postharvest performance. Our results show that reduced xanthophyll accumulation is the cause of yellowish coloring of YP and might be attributed to the reduced carotenoid sequestration capacity and upregulated expression of carotenoid cleavage dioxygenase genes. Constantly higher levels of polymethoxylated flavones (PMFs) during the infection and the storage stage might make significant contribution to the more strongly induced resistance against Penicillium digitatum and lower rotting rate. The present study demonstrates the feasibility of applying bud mutants to improve the postharvest performance of citrus fruits. PMID:26329679

  13. Citrus postharvest diseases and injuries related to impact on packing lines Doenças pós-colheita em citros e injúrias relacionadas ao impacto em linhas de beneficiamento

    Directory of Open Access Journals (Sweden)

    Ivan Herman Fischer

    2009-04-01

    Full Text Available Brazilian exports of fresh citrus represent less than 1% of the overall Brazilian production. Phytosanitary barriers and poor appearance stand out among the several reasons contributing to such low exporting/production ratio. The purpose of this work was to characterize postharvest injuries in 'Valencia' sweet oranges and 'Murcott' tangors produced for foreign markets after different processing stages in a packinghouse, as well as to identify critical points and impact extent on packing lines. Sampling was performed both after pre-washing and degreening the fruits, and also at the arrival on the packing table and in the pallet. They were stored for 21 days at 25ºC and 85% RH. The incidence of injuries was visually assessed every three days. An instrumented sphere with acceleration register was used to evaluate the extent of impacts (G, m/s² at the 19 transference points of the citrus processing line. There was low rot incidence (under 3.5% at the different stages of fruit processing, with slight increase after degreening in 'Valencia' orange and a decrease after fungicides treatment in 'Murcott' tangor. The main pathogens found in the oranges were Lasiodiplodia theobromae and Penicillium digitatum, which were surpassed by Colletotrichum gloeosporioides in the tangors. Impacts in the processing line were caused mainly by drops on hard surfaces, with 94.7% of them varying from 30 to 95 G. The greatest impacts were observed when fruits were transferred from the processing line to bins destined to degreening. Mechanical injuries related to oleocellosis increased until the arrival of fruits at the packing table.A exportação de frutos cítricos frescos representa menos que 1% da produção brasileira. Dentre os fatores atribuídos a esta baixa relação entre exportação e produção destacam-se as barreiras sanitárias e o aspecto visual de qualidade inferior. Este trabalho objetivou caracterizar os danos pós-colheita de frutos de laranja

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

    Science.gov (United States)

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

  15. Effectiveness of Postharvest Treatment with Chitosan to Control Citrus Green Mold

    OpenAIRE

    Mohamed El Guilli; Abdelkhalek Hamza; Christophe Clément; Mohamed Ibriz; Essaid Ait Barka

    2016-01-01

    Control of green mold, caused by Penicillium digitatum, by fungicides raises several problems, such as emergence of resistant pathogens, as well as concerns about the environment and consumers’ health. As potential alternatives, the effects of chitosan on green mold disease and the quality attributes of citrus fruits were investigated. Fruits were wounded then treated with different concentrations of chitosan 24 h before their inoculation with P. digitatum. The results of in vitro experiment ...

  16. Comparative transcriptomics and proteomics analysis of citrus fruit, to improve understanding of the effect of low temperature on maintaining fruit quality during lengthy post-harvest storage

    OpenAIRE

    Yun, Ze; Jin, Shuai; Ding, Yuduan; Wang, Zhuang; Gao, Huijun; Pan, Zhiyong; Xu, Juan; Cheng, Yunjiang; Deng, Xiuxin

    2012-01-01

    Fruit quality is a very complex trait that is affected by both genetic and non-genetic factors. Generally, low temperature (LT) is used to delay fruit senescence and maintain fruit quality during post-harvest storage but the molecular mechanisms involved are poorly understood. Hirado Buntan Pummelo (HBP; Citrus grandis × C. paradis) fruit were chosen to explore the mechanisms that maintain citrus fruit quality during lengthy LT storage using transcriptome and proteome studies based on digital...

  17. Assessment of Stubborn Disease Incidence in Citrus

    Science.gov (United States)

    Citrus stubborn disease, caused by Spiroplasma Citri, has occured in California for more than 90 years, however, detection methods for estimating disease incidence have not been well developed. Two 8 ha plots in Kern Co. CA were established and sampled in July and August, 2006. Different tissues o...

  18. Assessment of Stubborn Disease Incidence in Citrus

    Science.gov (United States)

    Citrus stubborn disease (CSD) has been a problem in California for over 90 years, yet, methods for rapidly detecting its causal agent, Spiroplasma citri, for use in estimating disease incidence have not been optimized. Two 8 ha blocks within two commercial groves were sampled in July and August, 20...

  19. Biofumigation on Post-Harvest Diseases of Fruits Using a New Volatile-Producing Fungus of Ceratocystis fimbriata.

    Science.gov (United States)

    Li, Qian; Wu, Lei; Hao, Jianjun; Luo, Laixin; Cao, Yongsong; Li, Jianqiang

    2015-01-01

    A variety of volatile organic compounds (VOCs) produced by Ceratocystis fimbriata have strong bioactivity against a wide range of fungi, bacteria and oomycetes. Mycelial growth, conidial production, and spore germination of fungi and oomycetes were significantly inhibited after exposure to cultures of C. fimbriata, and colony formation of bacteria was also inhibited. Two post-harvest diseases, peach brown rot caused by Monilinia fructicola and citrus green mold caused by Penicillium digitatum, were controlled during a 4-day storage by enclosing wound-inoculated fruits with 10 standard diameter Petri plate cultures of C. fimbriata in a 15 L box. The fruits were freshly inoculated at onset of storage and the cultures of C. fimbriata were 6 days old. Percentage of control was 92 and 97%, respectively. After exposure to C. fimbriata VOCs, severely misshapen hyphae and conidia of these two post-harvest pathogens were observed by scanning electron microscopy, and their pathogenicity was lost or greatly reduced. PMID:26147922

  20. Biofumigation on Post-Harvest Diseases of Fruits Using a New Volatile-Producing Fungus of Ceratocystis fimbriata.

    Directory of Open Access Journals (Sweden)

    Qian Li

    Full Text Available A variety of volatile organic compounds (VOCs produced by Ceratocystis fimbriata have strong bioactivity against a wide range of fungi, bacteria and oomycetes. Mycelial growth, conidial production, and spore germination of fungi and oomycetes were significantly inhibited after exposure to cultures of C. fimbriata, and colony formation of bacteria was also inhibited. Two post-harvest diseases, peach brown rot caused by Monilinia fructicola and citrus green mold caused by Penicillium digitatum, were controlled during a 4-day storage by enclosing wound-inoculated fruits with 10 standard diameter Petri plate cultures of C. fimbriata in a 15 L box. The fruits were freshly inoculated at onset of storage and the cultures of C. fimbriata were 6 days old. Percentage of control was 92 and 97%, respectively. After exposure to C. fimbriata VOCs, severely misshapen hyphae and conidia of these two post-harvest pathogens were observed by scanning electron microscopy, and their pathogenicity was lost or greatly reduced.

  1. Citrus phytophthora diseases: Management challenges and successes

    OpenAIRE

    Graham, J; Feichtenberger, E.

    2015-01-01

    Phytophthora spp. are present in nearly all citrus groves in Florida and Brazil and phytophthora-induced diseases, especially foot and root rot, have the potential to cause economically important crop losses. Disease-related losses due to root rot are difficult to estimate because fibrous root damage and yield loss are not always directly proportional. Challenges from phytophthora diseases have been addressed in both countries by enacting phytosanitary requirements for production of pathogen-...

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

    Science.gov (United States)

    Zhao, Wei; Bai, Jinhe; McCollum, Greg; Baldwin, Elizabeth

    2015-01-01

    Huanglongbing (HLB), presumably caused by the bacterium "Candidatus Liberibacter asiaticus," is a devastating citrus disease associated with excessive preharvest fruit drop. Lasiodiplodia theobromae (diplodia) is the causal organism of citrus stem end rot (SER). The pathogen infects citrus fruit under the calyx abscission zone (AZ-C) and is associated with cell wall hydrolytic enzymes similar to plant enzymes involved in abscission. By means of DNA sequencing, diplodia was found in "Ca. Liberibacter asiaticus"-positive juice from HLB-symptomatic fruit (S) but not in "Ca. Liberibacter asiaticus"-negative juice. Therefore, the incidence of diplodia in fruit tissues, the impact on HLB-related postharvest decay, and the implications for HLB-related preharvest fruit drop were investigated in Hamlin and Valencia oranges. Quantitative PCR results (qPCR) revealed a significantly (P < 0.001) greater incidence of diplodia in the AZ-C of HLB-symptomatic (S; "Ca. Liberibacter asiaticus" threshold cycle [CT] of <30) than in the AZ-C of in asymptomatic (AS; "Ca. Liberibacter asiaticus" CT of ≥30) fruit. In agreement with the qPCR results, 2 weeks after exposure to ethylene, the incidences of SER in S fruit were 66.7% (Hamlin) and 58.7% (Valencia), whereas for AS fruit the decay rates were 6.7% (Hamlin) and 5.3% (Valencia). Diplodia colonization of S fruit AZ-C was observed by scanning electron microscopy and confirmed by PCR test and morphology of conidia in isolates from the AZ-C after surface sterilization. Diplodia CT values were negatively correlated with ethylene production (R = -0.838 for Hamlin; R = -0.858 for Valencia) in S fruit, and positively correlated with fruit detachment force (R = 0.855 for Hamlin; R = 0.850 for Valencia), suggesting that diplodia colonization in AZ-C may exacerbate HLB-associated preharvest fruit drop. PMID:25344245

  3. Effectiveness of Postharvest Treatment with Chitosan to Control Citrus Green Mold

    Directory of Open Access Journals (Sweden)

    Mohamed El Guilli

    2016-03-01

    Full Text Available Control of green mold, caused by Penicillium digitatum, by fungicides raises several problems, such as emergence of resistant pathogens, as well as concerns about the environment and consumers’ health. As potential alternatives, the effects of chitosan on green mold disease and the quality attributes of citrus fruits were investigated. Fruits were wounded then treated with different concentrations of chitosan 24 h before their inoculation with P. digitatum. The results of in vitro experiment demonstrated that the antifungal activity against P. digitatum was improved in concert to the increase of chitosan concentration. In an in vivo study, green mold was significantly reduced by chitosan treatments. In parallel, chitinase and glucanase activities were enhanced in coated fruits. Evidence suggested that effects of chitosan coating on green mold of mandarin fruits might be related to its fungitoxic properties against the pathogen and/or the elicitation of biochemical defense responses in coated fruits. Further, quality attributes including fruit firmness, surface color, juice content, and total soluble solids, were not affected by chitosan during storage. Moreover, the loss of weight was even less pronounced in chitosan-coated fruit.

  4. Integration of Metabolomics and Subcellular Organelle Expression Microarray to Increase Understanding the Organic Acid Changes in Post-harvest Citrus Fruit

    Institute of Scientific and Technical Information of China (English)

    Xiaohua Sun; Zhaocheng Ma; Yunjiang Cheng; Xiuxin Deng; Andan Zhu; Shuzhen Liu; Ling Sheng; Qiaoli Ma; Li Zhang; Elsayed Mohamed Elsayed Nishawy; Yunliu Zeng; Juan Xu

    2013-01-01

    Citric acid plays an important role in fresh fruit flavor and its adaptability to post-harvest storage conditions. In order to explore organic acid regulatory mechanisms in post-harvest citrus fruit, systematic biological analyses were conducted on stored Hirado Buntan Pummelo (HBP; Citrus grandis) fruits. High-performance capillary electrophoresis, subcellular organelle expression microarray, real-time quantitative reverse transcription polymerase chain reaction, gas chromatography mass spectrometry (GC-MS), and conventional physiological and biochemical analyses were undertaken. The results showed that the concentration of organic acids in HBP underwent a regular fluctuation. GC-MS-based metabolic profiling indicated that succinic acid, g-aminobutyric acid (GABA), and glutamine contents increased, but 2-oxoglutaric acid content declined, which further confirmed that the GABA shunt may have some regulatory roles in organic acid catabolism processes. In addition, the concentration of organic acids was significantly correlated with senescence-related physiological processes, such as hydrogen peroxide content as well as superoxide dismutase and peroxidase activities, which showed that organic acids could be regarded as important parameters for measuring citrus fruit post-harvest senescence processes.

  5. Antifungal Edible Coatings for Fresh Citrus Fruit: A Review

    OpenAIRE

    Lluís Palou; Valencia-Chamorro, Silvia A.; Pérez-Gago, María B.

    2015-01-01

    According to their origin, major postharvest losses of citrus fruit are caused by weight loss, fungal diseases, physiological disorders, and quarantine pests. Cold storage and postharvest treatments with conventional chemical fungicides, synthetic waxes, or combinations of them are commonly used to minimize postharvest losses. However, the repeated application of these treatments has led to important problems such as health and environmental issues associated with fungicide residues or waxes ...

  6. The occurrence of postharvest diseases on apples resistant to scab

    Directory of Open Access Journals (Sweden)

    Hanna Bryk

    2012-12-01

    Full Text Available The occurrence of storage diseases on fruit of seven scab resistant apple cultivars (Freedom, Rajka, Topaz, Rubinola, Enterprise, Goldstar, GoldRush grafted on M.9 was investigated in 2001-2005. The trees were planted in 1995. It was found that after storage (4 and 6 months at 2°C, 85-90% RH the most severe appeared to be bull's eye rot (Pezicula spp.. The most sensitive cultivars to this disease were: Topaz, Freedom, Goldstar, the least sensitive were Rubinola, Enterprise, Rajka. Other postharvest diseases like gray mold (Botrytis cinerea, blue mold (Penicillium expansum and brown rot (Monilinia fructigena were not common. 'Rajka' and 'Goldstar' were susceptible to bitter pit, and 'Freedom' to superficial scald.

  7. Control of virus diseases of citrus.

    Science.gov (United States)

    Lee, Richard F

    2015-01-01

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

  8. Gamma radiation influences postharvest disease incidence of pineapple fruits

    International Nuclear Information System (INIS)

    The application of gamma radiation for improving the storage of pineapple fruits [Ananas comosus (L.) Merr. cv. Queen] has been studied in an attempt to reduce decay caused by fungal pathogens such as Ceratocystis paradoxa (Dade)-Moreau and Penicillium purpurogenum Stoll. Gamma radiation at 50, 75, 100, 150, and 250 Gy improved shelf life. The maximum tolerable dose was approximately 250 Gy. Fruits irradiated with up to 150 Gy and then stored at 25 to 28C maintained their texture better than did the controls. Radiation, particularly at doses 250 Gy, caused browning of the skin and softening of tissues. Browning increased with increasing radiation dose and storage duration. Excessively high doses promoted spoilage. Doses in the range of 50 to 250 Gy, in combination with storage at 11 to 13C, can be used to reduce postharvest losses in pineapple due to fungal diseases and senescence, thereby extending shelf life

  9. Assessment of application timing of Bacillus spp. to suppress pre- and postharvest diseases of apple

    OpenAIRE

    Poleatewich, A.M.; Ngugi, H.K.; Backman, Paul A.

    2012-01-01

    Metadata only record In response to consumer environmental and health concerns concerning chemical pesticides, more attention has been placed on the development of biological control agents for the mitigation of postharvest diseases. However, postharvest biocontrol products are not currently widely used due to variable efficacy. The purpose of this study is to determine the potential effectiveness of certain biological agents (Bacillus spp.) in the control of preharvest (foliar apple scab)...

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

    Science.gov (United States)

    Wang, Nian; Trivedi, Pankaj

    2013-07-01

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

  11. Characterization of a bacterial strain T132 and its effect on postharvest citrus anthracnose%生防细菌T132的鉴定及其对采后柑橘炭疽病的抑制效果

    Institute of Scientific and Technical Information of China (English)

    汪茜; 胡春锦; 柯仿钢; 史国英; 余功明; 黄思良

    2012-01-01

    [目的]柑橘(Citri)是世界上重要的果树.由胶孢炭疽菌[Colletotrichum gloeosporioides (Penz.)]引起的柑橘炭疽病是柑橘生产的主要病害之一.为探索对采后柑橘炭疽病有效的生防措施,分离鉴定柑橘根围土壤中一株细菌T132,并研究其特性及生防效果.[方法]根据菌株T132的形态特征、生理生化特性以及16S rDNA序列对其进行鉴定;通过连续8次在人工培养基上传代培养,测定该菌株的遗传稳定性;采用柑橘果实刺伤挑战接种和拮抗菌液直接浸泡健康果实两种方法研究该菌株对柑橘炭疽病的抑菌防病效果;利用洋葱伯克霍尔德氏菌致病因子的特异性引物检测菌株T132是否为潜在的人类致病菌.[结果]菌株T132鉴定为越南伯克霍尔德氏菌(Burkholderia vietnamiensis).连续8次在人工培养基上传代培养,菌株T132抑制胶孢炭疽病菌生长的能力没有发生明显改变.菌株T132对胶孢炭疽菌C.gloeosporioides引起的柑橘炭疽病有明显的防治作用,刺伤接种的防效为88.2%,自然发病的防效为54.9%.未检测到该拮抗菌株有人体致病相关的洋葱伯克霍尔德氏菌致病因子(BCESM)毒力基因.[结论]首次报道对柑橘采后炭疽病具有生防效果、对人类相对安全的越南伯克霍尔德氏菌生防菌株.%[Objective] Citrus (Citri) is an economically important fruit crop in the world. The anthracnose caused by Colletotrichum gloeosporioides (Penz.) Sacc. is one of the main diseases in citrus production. For exploring of an effective biocontrol measure against citrus postharvest anthracnose, a bacterial biocontrol strain T132 isolated from the rhizosphere soil of citrus was identified and characterized. The efficacy of the biocontrol strain against citrus postharvest anthracnose disease was evaluated. [Methods] Identification of strain T132 was carried out by using 16S rDNA sequence homology comparison as well as morphological, physiological

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

    Directory of Open Access Journals (Sweden)

    K. Padmavathi

    2016-09-01

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

  13. Microarray Expression Profiling of Postharvest Ponkan Mandarin(Citrus reticulata)Fruit under Cold Storage Reveals Regulatory Gene Candidates and Implications on Soluble Suqars Metabolism

    Institute of Scientific and Technical Information of China (English)

    Andan Zhu; Wenyun Li; Junli Ye; Xiaohua Sun; Yuduan Ding; Yunjiang Cheng; Xiuxin Deng

    2011-01-01

    Low temperature storage is widely applied to maintain citrus postharvest fruit quality.In this study,the transcriptional and metabolic changes in the pulp tissue of Citrus reticulata Blanco cv."Ponkan"were studied for three successive months under cold storage by Affymetrix Citrus GeneChip and gaschromatography,respectively.As many as 2 161 differentially expressed transcripts were identifiedbased on the bayesian hierarchical model.The statistical analysis of gene ontology revealed thatdefenselstress-related genes were induced quickly,while autophagy-related genes were overrepresentedin the late sampling stages,suggesting that the functional shift may coincide with the subsequent stepsof chilling development.We further classified the potential regulatory components and concluded thatethylene may play the crucial role in chilling development in this non-climacteric fruit.To cope withcomplex events,53 upregulated transcription factors represented regulatory candidates.Within these,the AP2-EREBP,C2H2 and AS2 gene family were overrepresented.Cold storage also causes alterationsin various metabolic pathways; a keen interest is paid in deciphering expression changes of solublesugar genes as increased evidence that soluble sugars act as both osmolytes and metabolite signalmolecules.Our results will likely facilitate further studies in this field with promising genetic candidatesduring chilling.

  14. Comparative transcriptomics and proteomics analysis of citrus fruit, to improve understanding of the effect of low temperature on maintaining fruit quality during lengthy post-harvest storage.

    Science.gov (United States)

    Yun, Ze; Jin, Shuai; Ding, Yuduan; Wang, Zhuang; Gao, Huijun; Pan, Zhiyong; Xu, Juan; Cheng, Yunjiang; Deng, Xiuxin

    2012-05-01

    Fruit quality is a very complex trait that is affected by both genetic and non-genetic factors. Generally, low temperature (LT) is used to delay fruit senescence and maintain fruit quality during post-harvest storage but the molecular mechanisms involved are poorly understood. Hirado Buntan Pummelo (HBP; Citrus grandis × C. paradis) fruit were chosen to explore the mechanisms that maintain citrus fruit quality during lengthy LT storage using transcriptome and proteome studies based on digital gene expression (DGE) profiling and two-dimensional gel electrophoresis (2-DE), respectively. Results showed that LT up-regulated stress-responsive genes, arrested signal transduction, and inhibited primary metabolism, secondary metabolism and the transportation of metabolites. Calcineurin B-like protein (CBL)-CBL-interacting protein kinase complexes might be involved in the signal transduction of LT stress, and fruit quality is likely to be regulated by sugar-mediated auxin and abscisic acid (ABA) signalling. Furthermore, ABA was specific to the regulation of citrus fruit senescence and was not involved in the LT stress response. In addition, the accumulation of limonin, nomilin, methanol, and aldehyde, together with the up-regulated heat shock proteins, COR15, and cold response-related genes, provided a comprehensive proteomics and transcriptomics view on the coordination of fruit LT stress responses.

  15. Comparative transcriptomics and proteomics analysis of citrus fruit, to improve understanding of the effect of low temperature on maintaining fruit quality during lengthy post-harvest storage.

    Science.gov (United States)

    Yun, Ze; Jin, Shuai; Ding, Yuduan; Wang, Zhuang; Gao, Huijun; Pan, Zhiyong; Xu, Juan; Cheng, Yunjiang; Deng, Xiuxin

    2012-05-01

    Fruit quality is a very complex trait that is affected by both genetic and non-genetic factors. Generally, low temperature (LT) is used to delay fruit senescence and maintain fruit quality during post-harvest storage but the molecular mechanisms involved are poorly understood. Hirado Buntan Pummelo (HBP; Citrus grandis × C. paradis) fruit were chosen to explore the mechanisms that maintain citrus fruit quality during lengthy LT storage using transcriptome and proteome studies based on digital gene expression (DGE) profiling and two-dimensional gel electrophoresis (2-DE), respectively. Results showed that LT up-regulated stress-responsive genes, arrested signal transduction, and inhibited primary metabolism, secondary metabolism and the transportation of metabolites. Calcineurin B-like protein (CBL)-CBL-interacting protein kinase complexes might be involved in the signal transduction of LT stress, and fruit quality is likely to be regulated by sugar-mediated auxin and abscisic acid (ABA) signalling. Furthermore, ABA was specific to the regulation of citrus fruit senescence and was not involved in the LT stress response. In addition, the accumulation of limonin, nomilin, methanol, and aldehyde, together with the up-regulated heat shock proteins, COR15, and cold response-related genes, provided a comprehensive proteomics and transcriptomics view on the coordination of fruit LT stress responses. PMID:22323274

  16. Evaluation of sulfur dioxide-generating pads and modified atmosphere packaging for control of postharvest diseases in blueberries

    Science.gov (United States)

    Postharvest diseases are a limiting factor of storage and shelf life of blueberries. Gray mold caused by Botrytis cinerea is one of the most important postharvest diseases in blueberries grown in California. In this study, we evaluated the effects of sulfur dioxide (SO2)-generating pads (designated ...

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

    Science.gov (United States)

    Boina, Dhana Raj; Bloomquist, Jeffrey R

    2015-06-01

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

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

    Science.gov (United States)

    Boina, Dhana Raj; Bloomquist, Jeffrey R

    2015-06-01

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

  19. Historical perspective on biological control of postharvest diseases – past, present, and future

    Science.gov (United States)

    The birth of the field of biological control of postharvest diseases can be traced back to 1984 when a researcher testing an antagonist (Bacillus subtilis) in the field to control brown rot of peaches (caused by Monilinia fructicola ) decided to apply the antagonist directly to the peach to control ...

  20. The myosin motor domain-containing chitin synthase PdChsVII is required for development, cell wall integrity and virulence in the citrus postharvest pathogen Penicillium digitatum.

    Science.gov (United States)

    Gandía, Mónica; Harries, Eleonora; Marcos, Jose F

    2014-06-01

    Chitin is an essential component of the fungal cell wall and a potential target in the development of new antifungal compounds, due to its presence in fungi and not in plants or vertebrates. Chitin synthase genes (chs) constitute a complex family in filamentous fungi and are involved in fungal development, morphogenesis, pathogenesis and virulence. In this study, additional chs genes in the citrus postharvest pathogen Penicillium digitatum have been identified. Comparative analyses included each PdChs in each one of the classes I to VII previously established, and support the grouping of these into three divisions. Disruption of the gene coding PdChsVII, which contains a short version of a myosin motor domain, has been achieved by using Agrobacterium tumefaciens-mediated transformation and revealed its role in the life cycle of the fungus. Disruption strains were viable but showed reduced growth and conidia production. Moreover, Pdchs mutants developed morphological defects as balloon-like enlarged cells and increased chitin content, indicative of an altered cell wall structure. Gene disruption also increased susceptibility to antifungal compounds such as calcofluor white (CFW), sodium dodecyl sulfate (SDS), hydroxide peroxide (H2O2) and commercial fungicides, but significantly no change was observed in the sensitivity to antifungal peptides. The PdchsVII mutants were able to infect citrus fruit and produced tissue maceration, although had reduced virulence and most importantly were greatly impaired in the production of visible mycelium and conidia on the fruit.

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

    Science.gov (United States)

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

  2. 佛手采后致病青霉的分离鉴定%Identification of Penicillium species causing post-harvest diseases of finger citron

    Institute of Scientific and Technical Information of China (English)

    李永强; 杨佳妮; 陈文荣; 路梅; 郭卫东

    2011-01-01

    Golden Finger citron (Citrusmedica var. Sarcodactylis Swingle), one of the traditional specialities of Jinhua.Zhejiang Province, has high ornamental and medicinal value. Green mould is the major fungus disease of Citrus fruits, causing substantial economic losses during the storage of post-harvest. To identify the exact species of the pathogenic fungus, an isolate belonged to genus Penicillium was isolated from the infected Golden Finger citron. Kochs postulation was completed by wounded-inoculation with the conidial suspension of Penicillium sp. On health Golden Finger. It was identified as Penicillium digitatum based on morphological characters and internal transcribed spacer (ITS) analysis. This result would be helpful for controlling post-harvest disease.%佛手(Citrusmedica var.sarcodactylis Swingle)又名九爪木、五指橘、佛手柑,为芸香科柑橘属常绿小乔木.主产于闽、粤、川、浙等省,其中浙江金华“金佛手”最为著名,被称为“果中之仙品,世上之奇卉”.其果形美观、色泽金黄、香味浓郁,具有药用价值高、贮藏期长的特点[1],是金华地区的传统特产之一.

  3. Comprehensive insights on how 2,4-dichlorophenoxyacetic acid retards senescence in post-harvest citrus fruits using transcriptomic and proteomic approaches.

    Science.gov (United States)

    Ma, Qiaoli; Ding, Yuduan; Chang, Jiwei; Sun, Xiaohua; Zhang, Li; Wei, Qingjiang; Cheng, Yunjiang; Chen, Lingling; Xu, Juan; Deng, Xiuxin

    2014-01-01

    Auxin-like 2,4-dichlorophenoxyacetic acid (2,4-D), a high-efficiency anti-stalling agent for the post-harvest fresh fruit industry, has had its use restricted due to environmental concerns. However, no other substitutes for 2,4-D are available to the post-harvest industry. Insights into the molecular mechanism underlying the effects of 2,4-D on fruit quality preservation will provide a theoretical basis for exploring new safe and effective anti-stalling agents. This study comprehensively analysed changes in the peel of Olinda Valencia orange [Citrus sinensis (L.) Osbeck] induced by 500 ppm 2,4-D using 'omic'-driven approaches. Transcriptional profiling revealed that transcriptional factor (mainly AP2/ERF, WRKY, and NAC family members), transport, and hormone metabolism genes were over-represented and up-regulated within 24h post-treatment (HPT). Stress defence genes were up-regulated, while cell wall metabolism genes were down-regulated after 48 HPT. However, secondary metabolism genes, especially phenylpropanoid and lignin biosynthesis-related genes, were over-represented at all the time points. Comparative proteomic analysis indicated that the expression of proteins implicated in stress responses (25%), hormone metabolism, and signal transduction (12%) significantly accumulated at the post-transcriptional level. Hormone levels detected by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) showed that abscisic acid, salicylic acid, and 2,4-D significantly increased, while ethylene production (detected by gas chromatography) decreased after 2,4-D treatment. In addition, lignin and water content in the fruit peel also increased and the epicuticle wax ultrastructure was modified. In conclusion, 2,4-D retarded fruit senescence by altering the levels of many endogenous hormones and by improving stress defence capabilities by up-regulating defence-related genes and proteins.

  4. Comprehensive insights on how 2,4-dichlorophenoxyacetic acid retards senescence in post-harvest citrus fruits using transcriptomic and proteomic approaches.

    Science.gov (United States)

    Ma, Qiaoli; Ding, Yuduan; Chang, Jiwei; Sun, Xiaohua; Zhang, Li; Wei, Qingjiang; Cheng, Yunjiang; Chen, Lingling; Xu, Juan; Deng, Xiuxin

    2014-01-01

    Auxin-like 2,4-dichlorophenoxyacetic acid (2,4-D), a high-efficiency anti-stalling agent for the post-harvest fresh fruit industry, has had its use restricted due to environmental concerns. However, no other substitutes for 2,4-D are available to the post-harvest industry. Insights into the molecular mechanism underlying the effects of 2,4-D on fruit quality preservation will provide a theoretical basis for exploring new safe and effective anti-stalling agents. This study comprehensively analysed changes in the peel of Olinda Valencia orange [Citrus sinensis (L.) Osbeck] induced by 500 ppm 2,4-D using 'omic'-driven approaches. Transcriptional profiling revealed that transcriptional factor (mainly AP2/ERF, WRKY, and NAC family members), transport, and hormone metabolism genes were over-represented and up-regulated within 24h post-treatment (HPT). Stress defence genes were up-regulated, while cell wall metabolism genes were down-regulated after 48 HPT. However, secondary metabolism genes, especially phenylpropanoid and lignin biosynthesis-related genes, were over-represented at all the time points. Comparative proteomic analysis indicated that the expression of proteins implicated in stress responses (25%), hormone metabolism, and signal transduction (12%) significantly accumulated at the post-transcriptional level. Hormone levels detected by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) showed that abscisic acid, salicylic acid, and 2,4-D significantly increased, while ethylene production (detected by gas chromatography) decreased after 2,4-D treatment. In addition, lignin and water content in the fruit peel also increased and the epicuticle wax ultrastructure was modified. In conclusion, 2,4-D retarded fruit senescence by altering the levels of many endogenous hormones and by improving stress defence capabilities by up-regulating defence-related genes and proteins. PMID:24215076

  5. Effect of thymol and linalool fumigation on postharvest diseases of table grapes.

    Science.gov (United States)

    Shin, Mi Ho; Kim, Jin-Hee; Choi, Hyo-Won; Keum, Yoong Soo; Chun, Se Chul

    2014-09-01

    Several postharvest diseases of table grapes (Vitis vinifera) occur during storage, and gray mold rot is a particularly severe disease because the causal agent, Botrytis cinerea, grows at temperatures as low as 0℃. Other postharvest diseases, such as those caused by Penicillium spp. and Aspergillus spp., also often lead to deterioration in the quality of table grapes after harvest. The use of plant essential oils such as thymol and linalool, to reduce postharvest diseases in several kinds of fruits, including table grapes and oranges, has received much attention in European countries. However, to the best of our knowledge there has been no report of the use of thymol fumigation to control gray mold in table grapes in Korea. Thymol (30 µg/mL) and linalool (120 µg/mL) significantly inhibited mycelial growth and conidia germination of B. cinerea. The occurrence rate of gray mold rot of B. cinerea and other unknown fungi was significantly reduced by fumigation with 30 µg/mL thymol in several table grape cultivars, such as Campbell early, Muscat Bailey A, Sheridan, and Geobong. In this study, fumigation with 30 µg/mL thymol, had no influence on the sugar content and hardness of grapes, but reduced fungal infection significantly. This suggests that 30 µg/mL thymol could be utilized to reduce deterioration of grapes due to gray mold and other fungal infections during long-term storage.

  6. Effect of thymol and linalool fumigation on postharvest diseases of table grapes.

    Science.gov (United States)

    Shin, Mi Ho; Kim, Jin-Hee; Choi, Hyo-Won; Keum, Yoong Soo; Chun, Se Chul

    2014-09-01

    Several postharvest diseases of table grapes (Vitis vinifera) occur during storage, and gray mold rot is a particularly severe disease because the causal agent, Botrytis cinerea, grows at temperatures as low as 0℃. Other postharvest diseases, such as those caused by Penicillium spp. and Aspergillus spp., also often lead to deterioration in the quality of table grapes after harvest. The use of plant essential oils such as thymol and linalool, to reduce postharvest diseases in several kinds of fruits, including table grapes and oranges, has received much attention in European countries. However, to the best of our knowledge there has been no report of the use of thymol fumigation to control gray mold in table grapes in Korea. Thymol (30 µg/mL) and linalool (120 µg/mL) significantly inhibited mycelial growth and conidia germination of B. cinerea. The occurrence rate of gray mold rot of B. cinerea and other unknown fungi was significantly reduced by fumigation with 30 µg/mL thymol in several table grape cultivars, such as Campbell early, Muscat Bailey A, Sheridan, and Geobong. In this study, fumigation with 30 µg/mL thymol, had no influence on the sugar content and hardness of grapes, but reduced fungal infection significantly. This suggests that 30 µg/mL thymol could be utilized to reduce deterioration of grapes due to gray mold and other fungal infections during long-term storage. PMID:25346603

  7. Mechanisms of action for 2-phenylethanol isolated from Kloeckera apiculata in control of Penicillium molds of citrus fruits

    OpenAIRE

    Liu, Pu; Cheng, Yunjiang; Yang, Meng; Liu, Yujia; CHEN, KAI; Long, Chao-an; Deng, Xiuxin

    2014-01-01

    Background Green and blue mold decay, caused by Penicillium digitatum and P. italicum, respectively, are important postharvest diseases of citrus. Biocontrol by microbes is an alternative to synthetic fungicide application. In this study, the antagonistic yeast strain Kloeckera apiculata 34–9 was used to investigate the action mechanisms involved in the biocontrol of postharvest diseases. Results An antifungal substance, 2-phenylethanol (PEA), was isolated from K. apiculata and demonstrated t...

  8. Burdock fructooligosaccharide induces fungal resistance in postharvest Kyoho grapes by activating the salicylic acid-dependent pathway and inhibiting browning.

    Science.gov (United States)

    Sun, Fei; Zhang, Pengying; Guo, Moran; Yu, Wenqian; Chen, Kaoshan

    2013-05-01

    Burdock fructooligosaccharide (BFO) is a natural elicitor from Arcitum lappa. The effects of BFO in controlling postharvest disease in grape, apple, banana, kiwi, citrus, strawberry, and pear were investigated. The disease index, decay percentage, and area under the disease progress curve indicated that BFO has general control effects on postharvest disease of fruits. Kyoho grapes were studied to elucidate the mechanism of BFO in boosting the resistance of grapes to Botrytis cinerea infection. BFO treatment induced upregulation of the npr1, pr1, pal, and sts genes, and inhibited the total phenol content decrease, which activated chitinase and β-1,3-glucanase. These results indicated that the salicylic acid-dependent signalling pathway was induced. The delayed colour change and peroxidase and polyphenoloxidase activity suggested that BFO delayed grape browning. The reduced respiration rate, weight loss, and titratable acidity prolonged the shelf life of postharvest grapes. BFO is a promising elicitor in postharvest disease control.

  9. Discrimination of Five Citrus Diseased Leaves by FTIR Spectroscopy

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2015-10-01

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

  11. Transcriptome profiling of citrus fruit response to huanglongbing disease.

    Directory of Open Access Journals (Sweden)

    Federico Martinelli

    Full Text Available 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.

  12. Transcriptome profiling of citrus fruit response to huanglongbing disease.

    Science.gov (United States)

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

    2012-01-01

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

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

    Science.gov (United States)

    Hao, Guixia; Stover, Ed; Gupta, Goutam

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Guixia Hao

    2016-07-01

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

  15. Antifungal Edible Coatings for Fresh Citrus Fruit: A Review

    Directory of Open Access Journals (Sweden)

    Lluís Palou

    2015-12-01

    Full Text Available According to their origin, major postharvest losses of citrus fruit are caused by weight loss, fungal diseases, physiological disorders, and quarantine pests. Cold storage and postharvest treatments with conventional chemical fungicides, synthetic waxes, or combinations of them are commonly used to minimize postharvest losses. However, the repeated application of these treatments has led to important problems such as health and environmental issues associated with fungicide residues or waxes containing ammoniacal compounds, or the proliferation of resistant pathogenic fungal strains. There is, therefore, an increasing need to find non-polluting alternatives to be used as part of integrated disease management (IDM programs for preservation of fresh citrus fruit. Among them, the development of novel natural edible films and coatings with antimicrobial properties is a technological challenge for the industry and a very active research field worldwide. Chitosan and other edible coatings formulated by adding antifungal agents to composite emulsions based on polysaccharides or proteins and lipids are reviewed in this article. The most important antifungal ingredients are selected for their ability to control major citrus postharvest diseases like green and blue molds, caused by Penicillium digitatum and Penicillium italicum, respectively, and include low-toxicity or natural chemicals such as food additives, generally recognized as safe (GRAS compounds, plant extracts, or essential oils, and biological control agents such as some antagonistic strains of yeasts or bacteria.

  16. 76 FR 23449 - Citrus Canker, Citrus Greening, and Asian Citrus Psyllid; Interstate Movement of Regulated...

    Science.gov (United States)

    2011-04-27

    ... to movement. Citrus canker is a plant disease that is caused by the bacterium Xanthomonas citri subsp... quarantined for citrus canker are found in Sec. 301.75-6. Citrus greening, also known as Huanglongbing disease of citrus, is considered to be one of the most serious citrus diseases in the world. Citrus...

  17. 78 FR 63369 - Citrus Canker, Citrus Greening, and Asian Citrus Psyllid; Interstate Movement of Regulated...

    Science.gov (United States)

    2013-10-24

    ... citrus canker are found in Sec. 301.75-6. Citrus greening, also known as Huanglongbing disease of citrus, is considered to be one of the most serious citrus diseases in the world. Citrus greening is a... areas of the world where the disease is endemic, citrus trees decline and die within a few years and...

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

    OpenAIRE

    Van Ekert, Evelien; Borovsky, D.; Powell, C A; Cave, R. D.; Alessandro, R. T.; Shatters, Jr., R. G.

    2014-01-01

    Diaphorina citri Kuwayama, the Asian citrus psyllid (ACP), is a devastating citrus pest due to its transmission of a phloem-limited bacterial pathogen, Candidatus Liberibacter asiaticus, that causes citrus greening. Psyllid control is a major part of effective greening disease management, and our research targets perturbation of insect juvenile hormone metabolism as a new psyllid control strategy.  Previous studies have shown that application of a juvenile hormone (JH) analogue, pyriproxyfen,...

  19. Antioxidant enzymes and fatty acid composition as related to disease resistance in postharvest loquat fruit.

    Science.gov (United States)

    Cao, Shifeng; Yang, Zhenfeng; Cai, Yuting; Zheng, Yonghua

    2014-11-15

    Two cultivars of loquat fruit were stored at 20°C for 10days to investigate the relationship between disease resistance, and fatty acid composition and activities of endogenous antioxidant enzymes. The results showed that decay incidence increased with storage time in both cultivars. A significantly lower disease incidence was observed in 'Qingzhong' fruit than in 'Fuyang', suggesting 'Qingzhong' had increased disease resistance. Meanwhile, 'Qingzhong' fruit also had lower levels of superoxide radical and hydrogen peroxide, and lower lipoxygenase activity, but higher levels of linolenic and linoleic acids and higher activities of catalase (CAT) and ascorbate peroxidase (APX) compared with 'Fuyang'. These results suggest that the higher levels of linolenic and linoleic acids and the higher activity of CAT and APX have a role in disease resistance of postharvest loquat fruit.

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

    Science.gov (United States)

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

    2014-07-01

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

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

    Science.gov (United States)

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

    2014-07-01

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

  2. Efeito de produtos alternativos para o controle do bolor verde (Penicillium digitatum em pós-colheita de citros Effect of the alternative products for control of green mold (Penicillium digitatum in post-harvest citrus fruit

    Directory of Open Access Journals (Sweden)

    DANIEL ANDRADE DE SIQUEIRA FRANCO

    2002-08-01

    Full Text Available O objetivo do trabalho foi verificar a ocorrência de sinergismo entre misturas de produtos alternativos aos fungicidas, para o controle do bolor verde (Penicillium digitatum em pós-colheita de citros. Foram testados dez produtos individualmente e trinta e cinco combinações destes produtos dois a dois, em comparação com tiabendazole e testemunha, com e sem inoculação. Os produtos testados não apresentaram efeito de sinergismo, exceto a mistura carbonato de Na + ácido bórico. Carbonato de Na e ácido bórico controlaram a doença em 78 e 87%, respectivamente, e, utilizando a mistura, o controle foi de 93%. Destacaram-se, ainda no controle da doença, o bicarbonato de Na, metabissulfito de Na e as misturas de bicarbonato de sódio + ácido bórico, carbonato de Na + carbonato de K, carbonato de Na + sorbato de K, bicarbonato de Na + carbonato de Na, controlando 92; 77; 81; 77; 75 e 71%, respectivamente. O tiabendazole utilizado como padrão controlou totalmente a doença.The objective of this work was verify the ocurrence of synergism of mixtures for alternative products to the fungicides for the control of the green mold (Penicillium digitatum in post-harvest citrus fruits. The efficiency of ten products, tested individually, and thirty five combinations among them, in pairs, were compared to thiabendazole and control, with and without inoculation. The products didn't present a synergism effect, except the mixture sodium carbonate + boric acid, that had a disease control of 93%. The products, sodium carbonate and boric acid controled 78 and 87%, respectively. The sodium bicarbonate, sodium methabisulphite and the mixtures of sodium bicarbonate + boric acid, sodium carbonate + potassium carbonate, sodium carbonate + potassium sorbate, sodium bicarbonate + sodium carbonate had a disease control of 92%, 77%, 81%, 77%, 75% and 71%, respectively. The fungicide treatment with thiabendazole used by standard had a whole disease control.

  3. Citrus leprosis research update

    Science.gov (United States)

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

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

    Science.gov (United States)

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

    2014-06-01

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

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

    Indian Academy of Sciences (India)

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

    2013-06-01

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

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

    Science.gov (United States)

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

    2013-06-01

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

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

    Science.gov (United States)

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

  8. The psorosis disease of citrus: a pale light at the end of the tunnel

    OpenAIRE

    Moreno, Pedro; Guerri, José; García, María Laura

    2015-01-01

    Abstract First reported in 1896, psorosis was the first citrus disease proven to be graft transmissible and also the first for which eradication and budwood certification programs were launched to prevent its economic damage. For many years psorosis etiology remained elusive and only in 1986 it was associated with the presence of virus-like particles in infected plants. However, in the last two decades a virus with unusual morphology (Citrus psorosis virus, CPsV) was characterized and closely...

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

    Science.gov (United States)

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

    2015-07-01

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

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

    Science.gov (United States)

    2011-02-15

    ... disease of citrus and referred to below as HLB) is considered to be one of the most serious citrus... world where the disease is endemic, citrus trees decline and die within a few years and may never.... Manjunath. Asian Citrus Psyllids (Sternorrhyncha: Psyllidae) and Greening Disease of Citrus: A...

  11. Breeding, genetic and genomic of citrus for disease resistance

    OpenAIRE

    Machado, Marcos A; Mariângela Cristofani-Yaly; Marinês Bastianel

    2011-01-01

    Although the citriculture is one of the most important economic activities in Brazil, it is based on a small number of varieties. This fact has contributed for the vulnerability of the culture regarding the phytosanitary problems. A higher number of varieties/genotypes with potential for commercial growing, either for the industry or fresh market, has been one of the main objectives of citrus breeding programs. The genetic breeding of citrus has improved, in the last decades, due to the possi...

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

    Science.gov (United States)

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

  13. Survival analysis: a tool in the study of post-harvest diseases in peaches

    Directory of Open Access Journals (Sweden)

    Cristiano Nunes Nesi

    2015-02-01

    Full Text Available Survival analysis is applied when the time until the occurrence of an event is of interest. Such data are routinely collected in plant diseases, although applications of the method are uncommon. The objective of this study was to use two studies on post-harvest diseases of peaches, considering two harvests together and the existence of random effect shared by fruits of a same tree, in order to describe the main techniques in survival analysis. The nonparametric Kaplan-Meier method, the log-rank test and the semi-parametric Cox's proportional hazards model were used to estimate the effect of cultivars and the number of days after full bloom on the survival to the brown rot symptom and the instantaneous risk of expressing it in two consecutive harvests. The joint analysis with baseline effect, varying between harvests, and the confirmation of the tree effect as a grouping factor with random effect were appropriate to interpret the phenomenon (disease evaluated and can be important tools to replace or complement the conventional analysis, respecting the nature of the variable and the phenomenon.

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

    Science.gov (United States)

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

    2013-02-01

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

  15. Comprehensive insights on how 2,4-dichlorophenoxyacetic acid retards senescence in post-harvest citrus fruits using transcriptomic and proteomic approaches

    OpenAIRE

    Ma, Qiaoli; Ding, Yuduan; Chang, Jiwei; Sun, Xiaohua; Zhang, Li; Wei, Qingjiang; Cheng, Yunjiang; Chen, Lingling; Xu, Juan; Deng, Xiuxin

    2013-01-01

    Auxin-like 2,4-dichlorophenoxyacetic acid (2,4-D), a high-efficiency anti-stalling agent for the post-harvest fresh fruit industry, has had its use restricted due to environmental concerns. However, no other substitutes for 2,4-D are available to the post-harvest industry. Insights into the molecular mechanism underlying the effects of 2,4-D on fruit quality preservation will provide a theoretical basis for exploring new safe and effective anti-stalling agents. This study comprehensively anal...

  16. PERFORMANCE EVALUATION OF VARIOUS STATISTICAL CLASSIFIERS IN DETECTING THE DISEASED CITRUS LEAVES

    Directory of Open Access Journals (Sweden)

    SUDHEER REDDY BANDI

    2013-02-01

    Full Text Available Citrus fruits are in lofty obligation because the humans consume them daily. This research aims to amend citrus production, which knows a low upshot bourgeois on the production and complex during measurements. Nowadays citrus plants grappling some traits/diseases. Harm of the insect is one of the major trait/disease. Insecticides are not ever evidenced effectual because insecticides may be toxic to some gracious of birds. Farmers get outstanding difficulties in detecting the diseases ended open eye and also it is quite expensive.Machine vision and Image processing techniques helps in sleuthing the disease mark in citrus leaves and sound job. In this search, Citrus leaves of four classes like Normal, Greasy spot, Melanose and Scab are collected and investigated using texture analysis based on the Color Co-occurrence Method (CCM to take Hue, Saturation and Intensity (HSI features. In the arrangement form, the features are categorised for all leafage conditions using k-Nearest Neighbor (kNN, Naive Bayes classifier (NBC, Linear Discriminate Analysis (LDA classifier and Random Forest Tree Algorithm classifier (RFT. The experimental results inform that proposed attack significantly supports 98.75% quality in automated detection of regular and struck leaves using texture psychotherapy based CCM method using LDA formula. Eventually all the classifiers are compared using Earphone Operative Characteristic contour and analyzed the performance of all the classifiers.

  17. 77 FR 59709 - Citrus Greening and Asian Citrus Psyllid; Quarantine and Interstate Movement Regulations

    Science.gov (United States)

    2012-10-01

    ...) 851-2286. SUPPLEMENTARY INFORMATION: Background Citrus greening, also known as Huanglongbing disease of citrus, is considered to be one of the most serious citrus diseases in the world. Citrus greening... citrus greening disease. In areas of the world where the disease is endemic, citrus trees decline and...

  18. Antifungal Activity of Some Constituents of Origanum vulgare L. Essential Oil Against Postharvest Disease of Peach Fruit.

    Science.gov (United States)

    Elshafie, Hazem S; Mancini, Emilia; Sakr, Shimaa; De Martino, Laura; Mattia, Carlo Andrea; De Feo, Vincenzo; Camele, Ippolito

    2015-08-01

    Plant essential oils (EOs) can potentially replace synthetic fungicides in the management of postharvest fruit and vegetable diseases. The aim of this study was to evaluate in vitro and in vivo effectiveness of thymol, carvacrol, linalool, and trans-caryophyllene, single constituents of the EO of Origanum vulgare L. ssp. hirtum against Monilinia laxa, M. fructigena, and M. fructicola, which are important phytopathogens and causal agents of brown rot of pome and stone fruits in pre- and postharvest. Moreover, the possible phytotoxic activity of these constituents was assessed and their minimum inhibitory concentration (MIC) was determined. In vitro experiment indicated that thymol and carvacrol possess the highest antifungal activity. Results of in vivo trials confirmed the strong efficacy of thymol and carvacrol against brown rot of peach fruits. The thymol MIC resulted to be 0.16 μg/μL against M. laxa and M. fructigena and 0.12 μg/μL against M. fructicola, whereas for carvacrol they were 0.02 μg/μL against the first two Monilinia species and 0.03 μg/μL against the third. Results of this study indicated that thymol and carvacrol could be used after suitable formulation for controlling postharvest fruit diseases caused by the three studied Monilinia species. PMID:25599273

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

    Science.gov (United States)

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

  20. Huanglongbing, a systemic disease, restructures the bacterial community associated with citrus roots.

    Science.gov (United States)

    Trivedi, Pankaj; Duan, Yongping; Wang, Nian

    2010-06-01

    To examine the effect of pathogens on the diversity and structure of plant-associated bacterial communities, we carried out a molecular analysis using citrus and huanglongbing as a host-disease model. 16S rRNA gene clone library analysis of citrus roots revealed shifts in microbial diversity in response to pathogen infection. The clone library of the uninfected root samples has a majority of phylotypes showing similarity to well-known plant growth-promoting bacteria, including Caulobacter, Burkholderia, Lysobacter, Pantoea, Pseudomonas, Stenotrophomonas, Bacillus, and Paenibacillus. Infection by "Candidatus Liberibacter asiaticus" restructured the native microbial community associated with citrus roots and led to the loss of detection of most phylotypes while promoting the growth of bacteria such as Methylobacterium and Sphingobacterium. In pairwise comparisons, the clone library from uninfected roots contained significantly higher 16S rRNA gene diversity, as reflected in the higher Chao 1 richness estimation (P citrus by "Ca. Liberibacter asiaticus" has a profound effect on the structure and composition of the bacterial community associated with citrus roots.

  1. Breeding, genetic and genomic of citrus for disease resistance

    Directory of Open Access Journals (Sweden)

    Marcos A. Machado

    2011-10-01

    Full Text Available Although the citriculture is one of the most important economic activities in Brazil, it is based on a small number of varieties. This fact has contributed for the vulnerability of the culture regarding the phytosanitary problems. A higher number of varieties/genotypes with potential for commercial growing, either for the industry or fresh market, has been one of the main objectives of citrus breeding programs. The genetic breeding of citrus has improved, in the last decades, due to the possibility of an association between biotechnological tools and classical methods of breeding. The use of molecular markers for early selection of zygotic seedlings from controlled crosses resulted in the possibility of selection of a high number of new combination and, as a consequence, the establishment of a great number of hybrids in field experiments. The faster new tools are incorporated in the program, the faster is possibility to reach new genotypes that can be tested as a new variety. Good traits should be kept or incorporate, whereas bad traits have to be excluded or minimized in the new genotype. Scion and rootstock can not be considered separately, and graft compatibility, fruit quality and productivity are essential traits to be evaluated in the last stages of the program. The mapping of QTLs has favored breeding programs of several perennial species and in citrus it was possible to map several characteristics with qualitative and quantitative inheritance. The existence of linkage maps and QTLs already mapped, the development of EST and BAC library and the sequencing of the Citrus complete genome altogether make very demanding and urgent the exploration of such data to launch a wider genetic study of citrus. The rising of information on genome of several organisms has opened new approaches looking for integration between breeding, genetic and genome. Genome assisted selection (GAS involves more than gene or complete genome sequencing and is becoming

  2. 咪鲜胺壳寡糖复合涂膜对脐橙果实采后品质的影响%Effect of Oligochitosan and Prochloraz Complex Coating on the Postharvest Quality of Citrus Sinensis Osbeck

    Institute of Scientific and Technical Information of China (English)

    聂青玉

    2012-01-01

    以脐橙为试材,果实采后以1%的壳寡糖为涂膜剂,分别与质量分数为0.01%,0.05%,0.10%浓度的咪鲜胺(有效成份450 g/L水乳剂)组合,浸泡处理后置于18~25℃,75%~85%RH环境中贮藏,比较与不涂膜处理及仅用1%的壳寡糖处理对脐橙贮藏品质、采后生理的影响.结果表明:不同浓度的咪鲜胺壳寡糖复合涂膜均能降低果实的失重率、腐烂率;延缓果实可溶性固形物、可滴定酸、还原性抗坏血酸含量的下降;抑制呼吸强度、丙二醛含量、相对电导率的上升;有效保持贮藏脐橙果实的感官品质、风味品质、营养品质,延长果实的贮藏期.其中,0.05%咪鲜胺与1%壳寡糖复合涂膜处理果实的各项品质、生理指标优于其它处理组,为有效延长脐橙果实贮藏时间的最经济、安全组合浓度.%Postharvest Citrus sinensis Osbeck has been stored after being soaked in 18 - 25 ℃ , 75% -85% RH environment,by the treatment of 1. 0% of Oligochitosan Combined with 0. 01 %, 0. 05% and 0. 1 % of Prochloraz (active ingredient 450 g/L of water emulsion) respectively. The effects of 1 % Oligochitosan treatment and uncoating treatment on the postharvest physiology and storage quality of Citrus sinensis Osbeck have been compared. The result illustrates that all kinds of Oligochitosan and Prochloraz Complex coating could reduce rate of weight loss and decay, delay the decline of soluble solids, titratable acidity and the content of ascorbic acid in fruits, inhibit the increase of the respiration rate, MDA content and relative electrical conductivity, maintain effectively the sensory, flavor, nutritional quality of Citrus sinensis Osbeck stored, and extend the storage period of Citrus sinensis Osbeck. Furthermore, the most economical and secure combination is 0.05% of Prochloraz (active ingredient 450 g/L of water emulsion) and 1% of Oligochitosan, which can make all kinds of the quality, physiological indexes

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

    Science.gov (United States)

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

    2014-02-01

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

  4. Respective Effects of Post-harvest Citrus Oil Induction and Vibration Stress Treatment on Oleocellosis in Jincheng Orange Peel(Citrus sinensis Osbeck cv. Jincheng)%采后橘油诱导及振动胁迫对贮藏期锦橙果皮油胞病的影响

    Institute of Scientific and Technical Information of China (English)

    刘丽丹; 吴日章; 曾凯芳

    2011-01-01

    The respective effects of post-harvest citrus oil induction and vibration stress treatment on oleocellosis in Jincheng orange peel were studied based on collapse index and color index.Oleocellosis in Jincheng orange peel showed a gradual increase as the concentration of citrus oil increased.The most serious oleocellosis in citrus peel could arise from 100% citrus oil treatment.In addition,mechanical vibration stress also could induce oleocellosis in Jincheng orange peel.Mechanical vibration stress at 500 r/min revealed the most obvious effect on oleocellosis formation.Moreover,Jincheng oranges treated with citrus oil or mechanical vibration stress were also used to explore the effect of storage temperature on oleocellosis in their peels.As a result,Jincheng oranges stored at 20 or 5 ℃had the severest change in oleocellosis.However,Jincheng oranges had the slightest change in oleocellosis during 5 ℃ storage.Therefore,these results can provide a theoretical reference for exploring the mechanisms and control strategies of oleocellosis.%以果皮塌陷指数和变色指数为测定指标,研究橘油及振动胁迫处理对锦橙果皮油胞病的影响。结果表明:随橘油体积分数增大果皮油胞病逐渐加重,并以100%橘油处理对锦橙果皮油胞病的诱导效果最明显;锦橙果皮油胞病发病程度随着振动胁迫强度增大而加重,其中500r/min的诱导效果最显著。另外,在橘油和振动胁迫处理后的果实在不同温度下贮藏时,发现20℃贮藏的锦橙果皮油胞病最为严重,0℃冷害温度也能加剧果实油胞病的发生,5℃贮藏的锦橙果皮油胞病最轻微。研究结果为进一步研究柑橘油胞病的发生机理及防控措施提供理论依据。

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

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

    2014-01-28

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

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

    Science.gov (United States)

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

    2014-01-28

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

  8. Citrus Genomics

    OpenAIRE

    Talon, Manuel; Gmitter, Fred G.Jr.

    2008-01-01

    Citrus is one of the most widespread fruit crops globally, with great economic and health value. It is among the most difficult plants to improve through traditional breeding approaches. Currently, there is risk of devastation by diseases threatening to limit production and future availability to the human population. As technologies rapidly advance in genomic science, they are quickly adapted to address the biological challenges of the citrus plant system and the world's industries. The hist...

  9. Synthesis of 4'-thiosemicarbazonegriseofulvin and its effects on the control of enzymatic browning and postharvest disease of fruits.

    Science.gov (United States)

    Pan, Zhi-Zhen; Zhu, Yu-Jing; Yu, Xiao-Jie; Lin, Qi-Fan; Xiao, Rong-Feng; Tang, Jian-Yang; Chen, Qing-Xi; Liu, Bo

    2012-10-31

    4'-Thiosemicarbazonegriseofulvin, a new thiosemicarbazide derivative of griseofulvin, was synthesized and evaluated for its potential in the control of enzymatic browning and postharvest disease of fruits. Browning on fruits is mainly due to the enzymatic oxidation of phenolic compounds catalyzed by tyrosinase. 4'-Thiosemicarbazonegriseofulvin could effectively inhibit the activity of tyrosinase, and its 50% inhibitory concentration (IC(50)) against tyrosinase was determined to be 37.8 μM. It was a reversible and noncompetitive inhibitor of tyrosinase, and its inhibition constant (K(I)) was determined to be 38.42 μM. The antifungal activity of 4'-thiosemicarbazonegriseofulvin was studied against four fungi (Fusarium oxysporum, Fusarium moniliforme, Fusarium solani, and Colletotrichum truncatum) that often cause postharvest diseases of fruits. The results showed that 4'-thiosemicarbazonegriseofulvin could also strongly inhibit the mycelial growth of the four target fungi; the 50% lethal concentration (LC(50)) values were 5.4, 7.0, 15.3, and 1.5 mM, respectively.

  10. Evaluation of yeasts obtained from Antarctic soil samples as biocontrol agents for the management of postharvest diseases of apple (Malus × domestica).

    Science.gov (United States)

    Vero, Silvana; Garmendia, Gabriela; González, M Belén; Bentancur, Oscar; Wisniewski, Michael

    2013-03-01

    Psychrotrophic yeasts were isolated from Antarctic soils, selected based on their ability to grow in apple juice at low temperatures, and were evaluated as potential biocontrol agents for the management of postharvest diseases of apple during cold storage. Among the species recovered, an isolate of Leucosporidium scottii, designated At17, was identified as a good biocontrol agent for blue and gray mold of two apple cultivars. The selected isolate produced soluble and volatile antifungal substances that were inhibitory to apple pathogens. Siderophore production was also demonstrated, but it did not appear to play a role in pathogen inhibition. The selected yeast had the capacity to form a biofilm when grown in apple juice, which is considered an important attribute of postharvest antagonists to successfully colonize wounds and intact fruit surfaces. At17 was resistant to commonly used postharvest fungicides, so application of a combination of low-dose fungicide along with the biocontrol agent could be used as an integrated management practice.

  11. Postharvest Disease Control of Colletotrichum gloeosporioides and Penicillium expansum on Stored Apples by Gamma Irradiation Combined with Fumigation

    Science.gov (United States)

    Cheon, Wonsu; Kim, Young Soo; Balaraju, Kotnala; Kim, Bong-Su; Lee, Byeong-Ho; Jeon, Yongho

    2016-01-01

    To study the control of postharvest decay caused by Colletotrichum gloeosporioides and Penicillium expansum, gamma irradiation alone or in combination with fumigation was evaluated to extend the shelf life of apples in South Korea. An irradiation dose of 2.0 kGy resulted in the maximum inhibition of C. gloeosporioides and P. expansum spore germination. The gamma irradiation dose required to reduce the spore germination by 90% was 0.22 and 0.35 kGy for C. gloeosporioides and P. expansum, respectively. Microscopic observations revealed that when the fungal spores were treated with gamma irradiation (4.0 kGy), conidial germination was stopped completely resulting in no germ tube formation in C. gloeosporioides. Treatment with the eco-friendly fumigant ethanedinitrile had a greater antifungal activity against C. gloeosporioides and P. expansum in comparison with the non-treated control under in vitro conditions. The in vitro antifungal effects of the gamma irradiation and fumigation treatments allowed us to further study the effects of the combined treatments to control postharvest decay on stored apples. Interestingly, when apples were treated with gamma irradiation in combined with fumigation, disease inhibition increased more at lower (< 0.4 kGy) than at higher doses of irradiation, suggesting that combined treatments reduced the necessary irradiation dose in phytosanitary irradiation processing under storage conditions. PMID:27721696

  12. Generating Asian citrus Psyllid Diaphorina citri Kuwayama (Homoptera: Psyllidae) with twisting wings to prevent the spread of citrus greening disease

    OpenAIRE

    El-Shesheny, I.; Harjeri, S.; Gowda, S.; Killiny, N.

    2014-01-01

    Huanglongbing (HLB) is seriously threatening and causing considerable economic losses to the citrus groves. Its Management depends critically on the control of the Asian citrus Psyllid (ACP), the vector of the cause of HLB, Candidatus Liberibacter asiaticus bacteria (CLas). Silencing genes by RNA interference (RNAi) is a promising technique to control pests. In this study, the abnormal disk wing (awd) has been selected from the available psyllid annotated genome. It has been known that awd ge...

  13. Enhancement or attenuation of disease by deletion of genes from Citrus tristeza virus.

    Science.gov (United States)

    Tatineni, Satyanarayana; Dawson, William O

    2012-08-01

    Stem pitting is a common virus-induced disease of perennial woody plants induced by a range of different viruses. The phenotype results from sporadic areas of the stem in which normal xylem and phloem development is prevented during growth of stems. These alterations interfere with carbohydrate transport, resulting in reduced plant growth and yield. Citrus tristeza virus (CTV), a phloem-limited closterovirus, induces economically important stem-pitting diseases of citrus. CTV has three nonconserved genes (p33, p18, and p13) that are not related to genes of other viruses and that are not required for systemic infection of some species of citrus, which allowed us to examine the effect of deletions of these genes on symptom phenotypes. In the most susceptible experimental host, Citrus macrophylla, the full-length virus causes only very mild stem-pitting symptoms. Surprisingly, we found that certain deletion combinations (p33 and p18 and/or p13) induced greatly increased stem-pitting symptoms, while other combinations (p13 or p13 plus p18) resulted in reduced stem pitting. These results suggest that the stem-pitting phenotype, which is one of more economically important disease phenotypes, can result not from a specific sequence or protein but from a balance between the expression of different viral genes. Unexpectedly, using green fluorescent protein-tagged full-length virus and deletion mutants (CTV9Δp33 and CTV9Δp33Δp18Δp13), the virus was found at pitted areas in abnormal locations outside the normal ring of phloem. Thus, increased stem pitting was associated not only with a prevention of xylem production but also with a proliferation of cells that supported viral replication, suggesting that at random areas of stems the virus can elicit changes in cellular differentiation and development.

  14. Effects of two kinds of medicinal plant extracts on citrus postharvest preservation%两种药用植物提取物对柑橘保鲜的影响

    Institute of Scientific and Technical Information of China (English)

    戴素明; 曾建国; 程辟; 陈义明; 周翔; 邓子牛

    2012-01-01

    为筛选能应用于柑橘保鲜的药用植物提取物,测定了博落回和虎杖提取物对柑橘绿霉菌的抑菌活性以及对柑橘保鲜的效果.结果表明:博落回和虎杖提取物均能抑制绿霉菌的生长,二者的有效中质量浓度分别为184.32、538.48 mg/L,博落回的抑菌效果比虎杖好;与清水对照相比,2种提取物处理柑橘的腐烂率均显著降低;与常规化学保鲜剂相比,2种提取物冰糖橙的腐烂率差异均无统计学意义,但椪柑的腐烂率均显著升高;2种提取物处理冰糖橙的失水率与常规化学保鲜剂处理的差异均无统计学意义,但显著高于清水处理,2种提取物对冰糖橙的防腐、保鲜能达到常规化学保鲜剂的效果.%For selection of medicinal plant extracts to be applied into citrus postharvest preservation, the inhibition effect of Macleaya cordata and Polygonum cuspidatum on Penicillium digitatum and its preservation effect during citrus storage were studied. The results were as follows: Both M. Cordata and P. Cuspidatum could inhibit growth of P. Digitatum, ED50 of which were 184.32 and 538.48 mg/L respectively, especially the inhibition effect of M cordata was better. With comparison of water treatment, the two kinds of medicinal plant extracts could both effectively prevent Bingtangcheng from decay. With comparison of conventional chemical preservative, the decay rates of Bingtangcheng respectively treated by the two kinds of medicinal plant extracts had no statistical significance, but Ponkan significantly increased. The water losing rates of Bingtangcheng respectively treated by the two kinds of medicinal plant extracts were no statistical significance compared with conventional chemical preservative, but the water losing rates of these three treatments were significantly lower than water treatment. The effects of the two kinds of medicinal plant extracts on decay and fresh-keeping of Bingtangcheng were similar to conventional chemical

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

    Science.gov (United States)

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

    2014-04-20

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

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

    Science.gov (United States)

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

    2014-04-20

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

  17. Early events of citrus greening (Huanglongbing) disease development at the ultrastructural level.

    Science.gov (United States)

    Folimonova, Svetlana Y; Achor, Diann S

    2010-09-01

    Citrus greening (Huanglongbing [HLB]) is one of the most destructive diseases of citrus worldwide. The causal agent of HLB in Florida is thought to be 'Candidatus Liberibacter asiaticus'. Understanding of the early events in HLB infection is critical for the development of effective measures to control the disease. In this work, we conducted cytopathological studies by following the development of the disease in citrus trees graft inoculated with 'Ca. L. asiaticus'-containing material under greenhouse conditions to examine the correlation between ultrastructural changes and symptom production, with the main objective of characterizing the early events of infection. Based on our observations, one of the first degenerative changes induced upon invasion of the pathogen appears to be swelling of middle lamella between cell walls surrounding sieve elements. This anatomical aberration was often observed in samples from newly growing flushes in inoculated sweet orange and grapefruit trees at the early "presymptomatic" stage of HLB infection. Development of symptoms and their progression correlated with an increasing degree of microscopic aberrations. Remarkably, the ability to observe the bacterium in the infected tissue also correlated with the degree of the disease progression. Large numbers of bacterial cells were found in phloem sieve tubes in tissue samples from presymptomatic young flushes. In contrast, we did not observe the bacteria in highly symptomatic leaf samples, suggesting a possibility that, at more advanced stages of the disease, a major proportion of 'Ca. L. asiaticus' is present in a nonviable state. We trust that observations reported here advance our understanding of how 'Ca. L. asiaticus' causes disease. Furthermore, they may be an important aid in answering a question: when and where within an infected tree the tissue serves as a better inoculum source for acquisition and transmission of the bacterium by its psyllid vector.

  18. Comparison on the Control Effects of Different Fungicides on Postharvest Citrus Green Mould%不同杀菌剂对采后柑桔绿霉病的防治效果比较

    Institute of Scientific and Technical Information of China (English)

    夏长秀; 李红叶; 王明爽; 彭龙; 娄伟; 严翔; 赖华荣; 凌永河; 朱从一; 方贻文

    2012-01-01

    在柑桔果实先刺伤接种柑桔绿霉病菌Penicillium digitatum孢子悬浮液再进行药剂浸果的条件下,研究了不同类型、不同浓度药剂对抗苯并咪唑类和咪唑类杀菌剂(双抗)或双敏感菌系的防治效果.结果表明:500或1 000 mg/L的甲基硫菌灵、咪鲜胺(扑霉灵)和抑霉唑(500mg/L)单剂,甲基硫菌灵和咪鲜胺(或扑霉灵)混剂对双抗菌系防治作用均低于50%;1 000 mg/L百可得单剂,500、1 000 mg/L百可得混配相同浓度咪鲜胺(或扑霉灵)均可控制双抗菌系引起的腐烂,防治效果在83%以上;1000mg/L咯菌腈对双抗菌系的防治效果为83.3%,500和1 000 mg/L嘧霉胺对双抗菌系的防治效果分别为91.1%和98.9%.500mg/L百可得、抑霉唑和嘧霉胺单剂,500mg/L百可得混配相同浓度咪鲜胺(或扑霉灵),500 mg/L甲基硫菌灵混配相同浓度扑霉灵对敏感菌系均有88%以上防治效果.基于研究结果,建议不再使用苯并咪唑类和咪唑类杀菌剂单剂或这两类杀菌剂混剂防治柑桔采后病害,可选择1 000 mg/L百可得(双胍辛烷苯基磺酸盐)单剂,500mg/L百可得和相同浓度咪唑类混剂.同时建议将嘧霉胺登记用于柑桔采后处理.%Effects of different types and concentrations of fungicides on post-harvest green mould disease were evaluated after wound- inoculation of the fruit with spore suspensions of Penicillium digitatum. Results showed that the control efficacy of 500 or 1 000 mg/L of thiophanate-methyl, 500 or 1 000 mg/L of prochlorazalone, 500 mg/L of imazalil, 500 mg/L of thiophanate-methyl plus 500 mg/L of prochloraz was lower than 50%. However, 1 000 mg/L of Bellkute, 500 mg/L of Bellkute + 500 mg/L of Prochloraz, 1 000 mg/L of Bellkute + 1 000 mg/L of Prochloraz showed good control results toward the double resistance isolates. The control efficacy of fludioxonil at 1 000 mg/L, pyrimethanil at 500 and 1 000 mg/L was 83. 3%, 91. 1% and 98. 9%, respectively. The control efficacy

  19. Chilling Temperature Enhances Ouality Reduction in Postharvest 'Shatangju' ( Citrus reticulata Blanco) Fruit%冷害导致砂糖橘果实品质劣变

    Institute of Scientific and Technical Information of China (English)

    庞学群; 陈燕妮; 黄雪梅; 汪跃华; 胡位荣; 张昭其

    2008-01-01

    将砂糖橘(Citrus reticulata Blanco)果实分别置于1、3、6和9℃下贮藏,比较其贮藏效果及冷害对果实品质的影响.结果表明:砂糖橘最适贮藏温度为6℃,在1~3℃贮藏易发生冷害.冷害导致果实外观品质下降,果肉乙醛和乙醇含量累积,果肉异味,品质下降.1℃贮藏的果实呼吸速率和乙烯释放速率较6℃高,丙二醛(MDA)含量增加,丙酮酸脱羧酶(PDC)和乙醇脱氢酶(ADH)活性大幅度提高.说明在冷害温度下,砂糖橘果肉异味是由于乙醛和乙醇累积产生,而果实呼吸速率的提高与PDC和ADH活性的增加密切相关.

  20. Use of AFLP for differentiation of Metschnikowia pulcherrima strains for postharvest disease biological control.

    Science.gov (United States)

    Spadaro, D; Sabetta, W; Acquadro, A; Portis, E; Garibaldi, A; Gullino, M L

    2008-01-01

    Metschnikowia pulcherrima occurs naturally on fruits, buds and floral parts of apple trees. Some strains are effective as biocontrol agents against postharvest decay of apples and other fruits. The usefulness of the amplified fragment length polymorphism (AFLP) technique was evaluated for the genetic analysis of 26 strains of M. pulcherrima, isolated from different sources in different geographical regions. With six AFLP primer pairs, 729 polymorphic bands were scored. The technique showed a high discriminatory power. Genetic relationships between strains were also estimated using AFLP. All the isolates from the carposphere of apple, previously tested as biocontrol agents, were grouped in a single cluster with a high bootstrap value (97), indicating robustness and reproducibility. AFLP patterns could clearly distinguish the different strains and research is in progress to use some putative specific bands for single tag sequence (STS) conversion to develop isolate-specific markers.

  1. 75 FR 34322 - Citrus Greening and Asian Citrus Psyllid; Quarantine and Interstate Movement Regulations

    Science.gov (United States)

    2010-06-17

    ... known as Huanglongbing disease of citrus, is considered to be one of the most serious citrus diseases in the world. Citrus greening is a bacterial disease, caused by strains of the bacterial pathogen... a tree with citrus greening disease. In areas of the world where the disease is endemic,...

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

    Science.gov (United States)

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

    2013-03-01

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

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

    OpenAIRE

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

    2011-01-01

    Xanthomonas axonopodis pv. citrumelo is a citrus pathogen causing citrus bacterial spot disease that is geographically restricted within the state of Florida. Illumina, 454 sequencing, and optical mapping were used to obtain a complete genome sequence of X. axonopodis pv. citrumelo strain F1, 4.9 Mb in size. The strain lacks plasmids, in contrast to other citrus Xanthomonas pathogens. Phylogenetic analysis revealed that this pathogen is very close to the tomato bacterial spot pathogen X. camp...

  4. Comprehensive meta-analysis, co-expression, and miRNA nested network analysis identifies gene candidates in citrus against Huanglongbing disease

    OpenAIRE

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

    2015-01-01

    Background Huanglongbing (HLB), the most devastating disease of citrus, is associated with infection by Candidatus Liberibacter asiaticus (CaLas) and is vectored by the Asian citrus psyllid (ACP). Recently, the molecular basis of citrus–HLB interactions has been examined using transcriptome analyses, and these analyses have identified many probe sets and pathways modulated by CaLas infection among different citrus cultivars. However, lack of consistency among reported findings indicates that ...

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

    Directory of Open Access Journals (Sweden)

    Hasabi Vahideh

    2014-07-01

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

  6. Yeasts isolated from figs (Ficus carica L.) as biocontrol agents of postharvest fruit diseases.

    Science.gov (United States)

    Ruiz-Moyano, S; Martín, A; Villalobos, M C; Calle, A; Serradilla, M J; Córdoba, M G; Hernández, A

    2016-08-01

    Fresh fruit is highly perishable during postharvest life, mainly due to fungal growth. Thus, fungal control is an important goal for the fruit industry. In this work, a selection of antagonistic yeasts isolated from fig and breba crops were screened in vitro. The isolated yeasts were challenged with three moulds isolated from decayed figs and breba crops, identified as Penicillium expansum M639 and Cladosporium cladosporioides M310 and M624, and pathogenic moulds Botrytis cinerea CECT20518 and Monilia laxa CA1 from culture collections. Two yeast isolates, Hanseniaspora opuntiae L479 and Metschnikowia pulcherrima L672, were selected for their ability to inhibit the growth of aforementioned moulds. These yeasts reduced the radial growth of moulds on PDA by between 45.23% and 66.09%. Antagonistic activity was associated with the interaction of live yeast cells with moulds. M. pulcherrima L672 apparently parasitised C. cladosporioides isolates. In addition, challenges were assayed using wounded apples and nectarines, with significant reductions in percent infection and lesion size for all moulds tested. To our knowledge, this is the first report identifying H. opuntiae as an antagonist against different pathogenic moulds. PMID:27052701

  7. Yeasts isolated from figs (Ficus carica L.) as biocontrol agents of postharvest fruit diseases.

    Science.gov (United States)

    Ruiz-Moyano, S; Martín, A; Villalobos, M C; Calle, A; Serradilla, M J; Córdoba, M G; Hernández, A

    2016-08-01

    Fresh fruit is highly perishable during postharvest life, mainly due to fungal growth. Thus, fungal control is an important goal for the fruit industry. In this work, a selection of antagonistic yeasts isolated from fig and breba crops were screened in vitro. The isolated yeasts were challenged with three moulds isolated from decayed figs and breba crops, identified as Penicillium expansum M639 and Cladosporium cladosporioides M310 and M624, and pathogenic moulds Botrytis cinerea CECT20518 and Monilia laxa CA1 from culture collections. Two yeast isolates, Hanseniaspora opuntiae L479 and Metschnikowia pulcherrima L672, were selected for their ability to inhibit the growth of aforementioned moulds. These yeasts reduced the radial growth of moulds on PDA by between 45.23% and 66.09%. Antagonistic activity was associated with the interaction of live yeast cells with moulds. M. pulcherrima L672 apparently parasitised C. cladosporioides isolates. In addition, challenges were assayed using wounded apples and nectarines, with significant reductions in percent infection and lesion size for all moulds tested. To our knowledge, this is the first report identifying H. opuntiae as an antagonist against different pathogenic moulds.

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

    Science.gov (United States)

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

  9. 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

    Directory of Open Access Journals (Sweden)

    Pappas Georgios J

    2008-01-01

    Full Text Available Abstract 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.

  10. A synergistic effect in controlling plum postharvest diseases occurs by applying UV-C light to sodium bicarbonate treated fruit.

    Science.gov (United States)

    D'Hallewin, G; Cubaiu, L; Ladu, G; Venditti, T

    2013-01-01

    The effectiveness of ultraviolet-C light (UV-C; 254 nm) alone at 0, 3, 6 and 12 kJm(-2), or combined with 0.0 or 0.5% (w7v) sodium bicarbonate (SBC), to control plum (Prunus domestica cv Stanley) postharvest decay caused by Penicillium expansum L. and Botrytis cinerea was investigated. First, fruit was sanitized and in one experiment plums were artificially wound-inoculated 24 h before treatments and afterwards kept at 25 degrees C with 90% RH for 7 days. In the second experiment, treatments were applied before fruit was spray-contaminated with conidia and then stored for 4 weeks at 5 degrees C and 90% RH (storage conditions). In both experiments, the highest degree of decay caused by the two pathogens was monitored when fruit stayed untreated (control), and a negligible reduction was achieved by treating with the sole salt or with a 3 kJm(-2) UV-C light. Compared to control (89 +/- 3% decay), the treatment of wound-inoculated fruit with 6 kJm(-2) provided a 35 and 38% reduction of P. expansum and B. cinerea decay, respectively. Meanwhile, 12 kJm(-2) provided an additional decrease of 25 and 27%, respectively. In both experiments, the best control of decay was attained when treatments with SBC and UV-C light were combined and the efficacy depended upon the sequence of application. Synergistic effects were found by applying the salt before UV-C light. When 6 or 12 kJm(-2) were employed following the 2% SBC treatment, no disease symptoms developed for either pathogens in both experiments. The same combination with 3 kJm(-2) resulted in a nearly 5 fold increase of efficacy compared to the sole light treatment. The combined treatments controlled the two pathogens to valuable levels and, since no quality losses were observed during storage, they could be considered as a suitable approach to contain postharvest losses of this fruit.

  11. Resistance to Gas Diffusion in Internal Tissues of Citrus Fruit

    OpenAIRE

    Dirpan, Andi

    2015-01-01

    Japan is a major citrus fruit-producing country, and Ehime Prefecture is one of the main citrus fruit producing regions in Japan. As many as 20 major citrus varieties are cultivated in Ehime. To further develop postharvest technology for quality preservation such as modified atmosphere packaging (MAP) and controlled atmosphere (CA) storage, creating an optimum gas concentration around fruit and vegetables have to be precisely achieved. However, the external atmosphere of fresh products in MAP...

  12. Doenças pós-colheita em laranja 'Pêra' produzida em sistema orgânico econvencional e resistência de Penicillium digitatum a fungicidas Postharvest diseases in 'Pêra' orange cultivated in organic and conventional systems and resistance of Penicillium digitatum to fungicides

    Directory of Open Access Journals (Sweden)

    Ivan Herman Fischer

    2013-03-01

    Full Text Available As doenças pós-colheita podem ser responsáveis por perdas tiabendazol (10 mg.L-1 e imazalil (1 mg.L-1. Frutos tratados com significativas ao citricultor. Este trabalho objetivou: a caracterizar imazalil apresentaram a menor incidência (5,4% de doenças pós-as doenças pós-colheita em laranjas 'Pêra' provenientes de cultivo colheita, enquanto que frutos provenientes de pomares orgânicos orgânico e convencional, com ou sem tratamento pós-colheita com apresentaram a maior incidência (25,2%. As principais doenças pósimazalil, comercializadas na CEAGESP; e b detectar a presença de colheita foram o bolor verde em frutos produzidos em sistema isolados de Penicillium digitatum resistentes a fungicidas em frutos convencional e as podridões pedunculares de lasiodiplodia e de com bolor verde. Frutos permaneceram em câmara úmida por 24 phomopsis em frutos orgânicos. A frequência relativa de isolados de horas, e por mais 13 dias a 25 ºC e 85% de UR. A incidência de P. digitatum resistentes ao fungicida tiabendazol foi menor em frutos doenças foi avaliada visualmente a cada 2-3 dias. A presença de P. orgânicos, enquanto a frequência de isolados de P. digitatum resistentes digitatum resistente a fungicidas foi avaliada em função do crescimento ao imazalil e à mistura tiabendazol+imazalil foi maior em frutos que micelial em meio batata-dextrose-ágar acrescido dos fungicidas receberam tratamento pós-colheita com imazalil.Postharvest diseases may be responsible for significant losses to added of the fungicides thiabendazole (10 mg.L-1 and imazalil (1 citrus growers. This study aimed to: a characterize the postharvest mg.L-1. Fruits treated with imazalil had lower incidence (5.4% of diseases in 'Pêra' oranges from organic and conventional crops, with postharvest diseases, while fruits from organic crop had the highest or without postharvest treatment with imazalil, marketed in incidence (25.2%. The main postharvest diseases were

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

    Institute of Scientific and Technical Information of China (English)

    Hongwei Zhao; Ruobai Sun; Ute Albrecht; Chellappan Padmanabhan; Airong Wang; Michael D.Coffey; Thomas Girke

    2013-01-01

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

  14. Incidence of post-harvest fungal diseases of ripe papaya in Mymensingh

    OpenAIRE

    Hamim, I.; Alam, M.Z.; Ali, M. A.; M. Ashrafuzzaman

    2014-01-01

    A survey was conducted during November, 2012 to May, 2013 to assess the status of major post harvest diseases of papaya fruits in the local markets of Mymensingh. Average percentage of diseased fruits at the markets were 29.83 and diseased fruits ranged from 20.40% to 38.04% during the study period. Highest percentage of diseased fruits (38.04%) was recorded in the month of May, 2013 followed by March, 2013 (37.98%). The minimum percentage of diseased fruits (20.40%) was recorded in January, ...

  15. Chitosan and fungicides on postharvest control of Guignardia citricarpa and on quality of 'Pêra Rio' oranges

    Directory of Open Access Journals (Sweden)

    Maria Cristina Canale Rappussi

    2011-09-01

    Full Text Available Citrus fruits are affected by the black spot disease caused by the fungus Guignardia citricarpa. Chitosan can be used as covering for fruits and may delay the ripening process and inhibit the growth of some fungi. Thus, the control of citrus black spot using chitosan and the fungicides thiabendazole and imazalil was assessed in addition to the physicochemical quality of 'Pêra Rio' oranges. The oranges were immersed into chitosan, thiabendazole or imazalil, and in chitosan mixed with both fungicides. The fruits were then stored at 25 °C, 80% RH, for 7 days and, after this storage period, subjected to physicochemical analyses. Chitosan in association with the fungicides reduced black spot in 'Pêra Rio' oranges and delayed the change in the orange skin colour from green to yellow during the postharvest storage. Total soluble solids, titratable acidity, pH, ascorbic acid content and ratio were not influenced by the treatments. Thus, chitosan applied with the fungicides thiabendazole and imazalil showed potential to control the development of black spot lesions on 'Pêra Rio' oranges during the postharvest period.

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

    Science.gov (United States)

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

    2015-04-01

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

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

    Science.gov (United States)

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

    2015-04-01

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

  18. 桂枝抑制柑橘采后两种病原菌活性物质研究%Antifungal Activity of Ramulus cinnamomi extracts against two key Citrus Postharvest Pathogens

    Institute of Scientific and Technical Information of China (English)

    万春鹏; 周梦娇; 刘洋; 陈金印

    2014-01-01

    In order to screen Chinese herbal medicine with potential antifungal activity from Chinese herb -al medicine extracts against two key Citrus postharvest pathogens ,namely Penicillium italicum and Penicillium digitatum.Solvent extract and silica gel chromatography were used to determine the antifungal materials from the active herb extracts .The results suggested that Ramulus cinnamomi,Cinnamomum cassia,Asarum sieboldii, Herba Moslae,Cortex Moutan and Artemisia apiacea had powerful inhibitive effects on the two pathogens and the inhibition zones were all over 20 mm.Moreover,the antifungal materials of Ramulus cinnamomi,Cinnamo-mum cassia and Asarum sieboldii all existed in the ethyl acetate fraction .Ramulus cinnamomi showed the best inhibitive effects on the two pathogens ,and the inhibitive zones were 34.57 mm and 31.56 mm,respectively. While the MIC were 3.125 mg/mL and 6.25 mg/mL,respectively;the MFC were 6.25 mg/mL and 12.5 mg/mL,respectively.The inhibition zones of the ethyl acetate fraction of Ramulus cinnamomi were 45.33 mm and 40.53 mm,respectively.Four subfractions (Fr.1-Fr.4) were obtained from the ethyl acetate fraction by the silica gel chromatography .Fr.1 showed the best antifungal activity and cinnamaldehyde was the main antifungal material in Fr.1 detected by HPLC .%从中草药提取物中筛选对引起柑橘采后主要病害的两株真菌---意大利青霉( Penicillium italicum)和指状青霉( Penicillium digitatum)有抑菌活性的中草药;采用溶剂萃取和硅胶柱色谱对具有较好抑菌活性的中草药提取物进一步分离纯化,确定其抑菌活性物质。结果表明:桂枝、桂皮、细辛、香薷、牡丹皮和青蒿6种提取物对这两株真菌均有较好的抑菌效果,抑菌圈直径均达20 mm以上。其中桂枝、桂皮和细辛的抗菌活性物质主要存在于乙酸乙酯部位,且桂枝的抑菌活性最强,对意大利青霉和指状青霉的抑菌圈直径分别为34.57 mm和31

  19. Evaluation of food additives as alternative or complementary chemicals to conventional fungicides for the control of major postharvest diseases of stone fruit for the control of major postharvest diseases of stone fruit

    Science.gov (United States)

    Among more than twenty food additives and GRAS (generally regarded as safe) compounds that were tested at three concentrations in in vivo primary screenings with several cultivars of California peaches, nectarines, and plums that had been artificially inoculated with seven major postharvest pathogen...

  20. Qualidade pós-colheita de pomelos (Citrus paradisi Macf. produzidos em plantações iniciais no estado do Ceará, Brasil Postharvest quality of grapefruit (Citrus paradisi Macf. produced from initial plantings in Ceará state, Brazil

    Directory of Open Access Journals (Sweden)

    Francisca Ligia de Castro Machado

    2011-12-01

    Full Text Available O estado do Ceará, nordeste do Brasil, vem ganhando atenção como o mais emergente Estado produtor de frutos no país. Citros, incluindo pomelos, tradicionalmente cultivados no sul, vem sendo plantados no Estado. No entanto, ainda não existem informações sobre qualidade de pomelos cultivados localmente. Este estudo objetivou examinar a qualidade pós-colheita de pomelos 'Star Ruby' e 'Ruby Red' quanto ao tamanho e forma, coloração da polpa, espessura da casca, rendimento do suco, sólidos solúveis (SS, acidez titulável (AT, pH, relação SS/AT e níveis de ácido ascórbico na colheita e após 15 dias de armazenamento. Um segundo lote de frutos foi examinado quanto a perda de massa e coloração externa. Os resultados sugerem que os pomelos apresentam bom tamanho e forma, com coloração externa alaranjada e interna avermelhada e espessura da casca apropriada. Frutos apresentaram um bom rendimento de suco, rico em ácido ascórbico, e com valores de SS, AT e pH comparáveis aos reportados para frutos cultivados em áreas tradicionais do país. A relação SS/AT encontra-se acima do mínimo necessário para um bom sabor. A coloração da casca variou de amarelado a alaranjado. Perda de massa aumentou, enquanto o ângulo de cor hue decresceu, seguindo o mesmo padrão para as duas variedades.Ceará state, northeast Brazil, is gaining attention as the most significant emerging fruit production region in the country. Citrus, including grapefruit, traditionally cultivated in the south, was recently implanted. However, data on postharvest quality of grapefruit grown under local conditions are nonexistent. A study was designed to examine postharvest quality of locally grown 'Star Ruby' and 'Ruby Red' grapefruits. Fruits were assessed for size and shape, pulp color, peel thickness, juice content, soluble solids (SS, titratable acidity (TA, pH, SS/TA ratio, and ascorbic acid at harvest and at the fifteenth day of storage. A second set of fruits

  1. Enzymatic modification enhances the protective activity of citrus flavonoids against alcohol-induced liver disease.

    Science.gov (United States)

    Park, Ho-Young; Choi, Hee-Don; Eom, Hyojin; Choi, Inwook

    2013-08-15

    Alcoholic liver disease (ALD) can be developed by a prolonged or large intake of alcohol in a short period of time. ALD is considered as a leading cause for a liver injury in modern dietary life. This study was aimed to investigate the effects of orally administrated citrus flavonoids (CFs) and their enzymatically modified ones (EM-CFs) to prevent ALD. Hesperidin and narirutin were extracted from peels of Citrus unshiu by ultra-sonication and purified further. These CFs were modified enzymatically through glycosylation and de-rhamnosylation by the actions of cyclodextrin glucanotransferase (CGTase) and hesperidinase, respectively. CFs and EM-CFs were fed to ICR mouse along with ethanol for 8 weeks, and changes in lipid contents, lipid peroxidation, GSH, antioxidant enzymes activity and proinflammatory cytokines in hepatic tissues were observed. Administration of CFs and EM-CFs along with alcohol significantly suppressed increases in prognostic parameters of a hepatocellular injury. Especially, EM-CFs fed groups maintained malondialdehyde, GSH levels and catalase activity in hepatic tissues close to those of the normal diet fed group. Abrupt increases in proinflammatory cytokines such as IκB-α, TNF-α, IL-1β and IL-6 in hepatocytes due to a chronic alcohol uptake were significantly suppressed by co-administration of EM-CFs. These results indicate that although the administration of CFs can alleviate ALD through preventing excessive lipid formation, protecting the antioxidant system and suppressing induction of inflammation in hepatocytes, their effectiveness can be further improved by glycosylation and de-rhamnosylation.

  2. Effects of pre- and post-harvest application of selenium on inducing disease resistance and selenium accumulation in fruits

    Science.gov (United States)

    Botrytis cinerea, a ubiquitous fungal pathogen, causes severe damage (gray mold rot) on a large number of economically important fruits, vegetables, and ornamental crops at both pre- and post-harvest, which renders fruits unmarketable. Penicillium expansum is a widely spread fungal pathogen that cau...

  3. Identification of Bio-Control Strain 1505 and Its Effect on Controlling Postharvest Citrus Anthracnose%生防细菌1505的鉴定及其对采后柑橘炭疽病的抑制效果

    Institute of Scientific and Technical Information of China (English)

    汪茜; 胡春锦; 黄思良; 柯仿钢

    2011-01-01

    采用细菌学方法及分子生物学技术对菌株1505进行鉴定,并对其在防治采后柑橘炭疽病上的效果进行研究.结果显示,菌株1505对柑橘炭疽病菌具有拮抗活性,其活菌悬浮液在PDA平板上对柑橘炭疽病菌产生明显抑制作用,而灭菌发酵液和去除菌体的发酵液均无抑菌效果;连续8次在人工培养基上转代培养,菌株1505对柑橘炭疽病菌生长的抑制力没有发生明显改变;菌株1505对胶孢炭疽菌[Colletotrichum gloeosporioides(Penz.)Sacc.]引起的柑橘炭疽病有明显的防治作用,刺伤接种的防效为48.8%,自然发病的防效为46.3%.根据形态学特征和生理生化反应,结合16SrDNA序列分析结果,将菌株1505鉴定为枯草芽孢杆菌(Bacillus subtilis).%The present study aimed to use the bacteriological method and molecular biology technique to identify the strain 1505 and study its efficacy in controlling postarvest Citrus anthracnose. The results showed that the strain 1505 had antagonistic actwity against Colletatrichum gloeosyorioides. its cell auspension showed significant suppressive activity against C. gloeosporioides , while no suppressive activity was detected in high.temperature-sterilized fermentation fluid or cell-free fermentation fluid. Lesa change in the suppressive ability of strain 1505 against C. gloeosporioides was observed during 8 continuously subculture in artificial media. The strain 1505 had significant efficacy in controlling Citrus anthracnose disease causing by C. gloeosporioides. The average efficacies of strain 1505 in controlling the disease were 48. 8 % in artificial inoculation test and 46. 3 % in natural infection test. Strain 1505 was identified as Bacillus subtilis based on the physiological and biochemical properties and its 16S rDNA sequence analysis.

  4. Advance in research on biological control of postharvest diseases of fruits by Bacillus subtilis%枯草芽孢杆菌防治果实采后病害的研究进展

    Institute of Scientific and Technical Information of China (English)

    张彩霞; 李壮; 康国栋; 张利益; 丛佩华; 田义

    2009-01-01

    Postharvest fruit diseases have produced a severe effect on the storage and quality of fruits. Health hazard and environmental pollution concerns regarding use of fungicides has enhanced interest in finding effective alternative to pesticides for control of postharvest diseases of fruits. Beneficial bacteria like Bacillus subtilis, a model organism of Gram-positive bacteria, were proven to be an efficient alternative antagonistic hacterium to synthetic fungicides to suppress postharvest diseases of fruits. This paper introduces the mechanisms of the antagonist B. subtilis against postharvest diseases of fruits, reviews the recent research advances, exhibits the availability and potential of B. subtilis toward postharvest fruit diseases, and provides important references to the future development of new postharvest biocontrol products.%果实采后病害严重影响水果的贮藏及果品质量.因化学杀菌剂在应用中存在危害人体健康及污染环境等一系列问题.利用枯草芽孢杆菌(Bacillus subtilis)防治果实采后病害的生物防治手段作为一种有效替代方法受到人们的广泛关注.枯草芽孢杆菌是革兰氏阳性细菌研究的模式菌株,为重要的生防菌源.在探讨枯草芽孢杆菌防治果实采后病害拮抗机制的基础上,阐述了该领域的研究成果和最新进展,展示了枯草芽孢杆菌应用于果实采后病害生物防治的可行性和潜力,为今后果实采后生防产品的开发提供新的研究思路.

  5. Biocontrol Efficacy of Two Antagonistic Yeasts Against Postharvest Diseases in Peach Fruits During Storage Periods

    Institute of Scientific and Technical Information of China (English)

    LIN Li; TIAN Shi-ping; QIN Guo-zheng; XU Yong

    2003-01-01

    Two antagonistic yeasts, Thichosporon pullulans and Cryptococcus laurentii, were investigated for their biocontrol potential to blue mold rot and rhizopus rot on harvested peach fruits (Prunus persica L. Batsch, cv. Okubao), alone or in combination with a Iow dose of iprodione (50 μg mi-1 ). The results indicated that T. pullulans and C. laurentii were effective at reducing disease incidence and severity of blue mold rot and rhizopus rot in peach fruits. Biocontrol efficacy of C. laurentii and T. pullulans were significantly enhanced by combination with a Iow dose of iprodione (50 μg mi-1) against blue mold and rhizopus rot in peach fruits. T. pullulans and C. laurentii combined with a low dose of iprodione (50 μg mi-1 ) resulted in better disease control than either iprodione or the yeasts used alone. Dipping fruits in suspensions of antagonist cells showed the similar control effect as the treatment with iprodione (500 μg ml-1 ).

  6. Development of "Boni-Protect" - a yeast preparation for use in the control of postharvest diseases of apples

    OpenAIRE

    Weiss, Armin; Mögel, Gudrun; Kunz, Stefan

    2006-01-01

    Postharvest pathogens cause major losses in apple production. Gloeosporium album (Pezicula alba) and Gloeosporium perennans (Pezicula malicorticis) are the main pathogens in organic fruit growing. There are several microorganisms with an antagonistic efficency against these fungi. Out of these organisms two yeast isolates have been chosen to develop the plant strengthener Boni-Protect. Boni-Protect reduced the symp-tom development of P. malicorticis, B. cinerea and P. expansum after artificia...

  7. Identification of a new enamovirus associated with citrus vein enation disease by deep sequencing of small RNAs.

    Science.gov (United States)

    Vives, Mari Carmen; Velázquez, Karelia; Pina, José Antonio; Moreno, Pedro; Guerri, José; Navarro, Luis

    2013-10-01

    To identify the causal agent of citrus vein enation disease, we examined by deep sequencing (Solexa-Illumina) the small RNA (sRNA) fraction from infected and healthy Etrog citron plants. Our results showed that virus-derived sRNAs (vsRNAs): (i) represent about 14.21% of the total sRNA population, (ii) are predominantly of 21 and 24 nucleotides with a biased distribution of their 5' nucleotide and with a clear prevalence of those of (+) polarity, and (iii) derive from all the viral genome, although a prominent hotspot is present at a 5'-proximal region. Contigs assembled from vsRNAs showed similarity with luteovirus sequences, particularly with Pea enation mosaic virus, the type member of the genus Enamovirus. The genomic RNA (gRNA) sequence of a new virus, provisionally named Citrus vein enation virus (CVEV), was completed and characterized. The CVEV gRNA was found to be single-stranded, positive-sense, with a size of 5,983 nucleotides and five open reading frames. Phylogenetic comparisons based on amino acid signatures of the RNA polymerase and the coat protein clearly classifies CVEV within the genus Enamovirus. Dot-blot hybridization and reverse transcription-polymerase chain reaction tests were developed to detect CVEV in plants affected by vein enation disease. CVEV detection by these methods has already been adopted for use in the Spanish citrus quarantine, sanitation, and certification programs.

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

    Science.gov (United States)

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

  9. Antioxidant activity of Citrus fruits.

    Science.gov (United States)

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

    2016-04-01

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

  10. Antioxidant activity of Citrus fruits.

    Science.gov (United States)

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

    2016-04-01

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

  11. Yeasts from native Brazilian Cerrado plants: Occurrence, diversity and use in the biocontrol of citrus green mould.

    Science.gov (United States)

    Sperandio, Eugenio Miranda; do Vale, Helson Mario Martins; Moreira, Geisianny Augusta Monteiro

    2015-11-01

    Yeasts are some of the most important postharvest biocontrol agents. Postharvest oranges frequently deteriorate due to green mould (Penicillium digitatum), which causes significant losses. The aims of this study were to determine the composition and diversity of yeasts on plants of the Brazilian Cerrado and to explore their potential for inhibiting citrus green mould. Leaves and fruit of Byrsonima crassifolia and Eugenia dysenterica were collected from Cerrado conservation areas, and thirty-five yeasts were isolated and identified by sequencing the D1-D2 domain of the rDNA large subunit (26S). The isolates represented the Aureobasidium, Meyerozyma, Candida, and Pichia genera. Three isolates identified as Aureobasidium pullulans exhibited potential for the control of P. digitatum in both in vitro and in vivo tests; these isolates reduced the incidence of disease and increased the storage time of fruit. Aureobasidium. pullulans has immense potential for the biological control of filamentous fungi. PMID:26466874

  12. Occurrence and Control of Citrus Yellow Shoot Disease in Meizhou City%梅州市柑橘黄龙病的发生与防治

    Institute of Scientific and Technical Information of China (English)

    刘蕊; 杜小珍; 钟进良; 饶小珍; 温清英; 张雄基; 马瑞丰

    2012-01-01

    对梅州市柑橘黄龙病的发生情况进行普查,对采集的152个黄龙病样进行检测,结果表明:梅州地区已有柑橘黄龙病的发生,在此基础上提出防治方法,以为当地柑橘黄龙病的防治提供参考。%The occurrence status of citrus yellow shoot disease in Meizhou City was investigated in the paper,152 collected samples of yellow shoot disease were tested.The results showed that citrus yellow shoot disease had occurred in Meizhou Area.Control methods were proposed,in order to provide references for preventing citrus yellow shoot disease.

  13. Relationship between Post-harvest Physiological Disorders and Ultra-structural Change of Citrus Peel%采后柑橘生理病害与果皮超微结构变化的关系

    Institute of Scientific and Technical Information of China (English)

    崔文静; 刘丽丹; 曾凯芳

    2011-01-01

    采后柑橘果实在贮藏过程中,在不适的环境因子作用下,导致果实生理代谢发生障碍,从而产生了生理性病害,如冷害、油胞病、褐斑病以及水肿病等,在一定程度上降低了果实的感官品质和耐贮性,进而影响果实的食用品质。本文从柑橘主要生理病害与果皮细胞膜、细胞壁和亚细胞结构变化的关系着手,对采后柑橘果实几种常见生理性病害发生过程中果皮超微结构的变化进行了综述,旨在为采后柑橘果实生理病害发病机理的深入研究提供参考。%Due to inappropriate environmental factors causing physiological metabolism disorders,post-harvest citrus fruits during storage can produce a number of physiological disorders including chilling injury,oleocellosis,rind pitting and edema.These physiological disorders can reduce the sensory quality,storability and edible quality of fruits.In this paper,the relationships between major physiological disorders of citrus peel and the changes of cell membrane,cell wall and subcellular structures are reviewed.Meanwhile,the ultra-structural changes of citrus peel during the occurrence of these physiological disorders are discussed for the purpose of providing a theoretical basis for exploring the mechanisms and control methods of physiological disorders in citrus fruits.

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

    Science.gov (United States)

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

    2014-08-01

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

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

    Directory of Open Access Journals (Sweden)

    Nik J Cunniffe

    2014-08-01

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

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

    Science.gov (United States)

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

    2014-08-01

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

  17. Citrus tristeza virus-host interactions

    OpenAIRE

    Dawson, William O.; Garnsey, Stephen M.; Satyanarayana eTatineni; Folimonova, Svetlana Y.; Scott J Harper; S eGowda

    2013-01-01

    Citrus tristeza virus (CTV) is a phloem-limited virus whose natural host range is restricted to citrus and related species. Although the virus has killed millions of trees, almost destroying whole industries, and continually limits production in many citrus growing areas, most isolates are mild or symptomless in most of their host range. There is little understanding of how the virus causes severe disease in some citrus and none in others. Movement and distribution of CTV differs considerably...

  18. Characterizing culturable microflora of nectarines: bacteria and their potential for biological control of postharvest fruit decay

    Science.gov (United States)

    Microorganisms isolated from fruit surfaces have been used to control postharvest decays of fruit. However, there is little information on microflora colonizing surfaces of fruits other than grapes, apples, and citrus. We characterized bacterial microflora on nectarine fruit surfaces during fruit ...

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

    Science.gov (United States)

    Bové, Joseph Marie; Ayres, Antonio Juliano

    2007-01-01

    The state of São Paulo (SSP) is the first sweet orange growing region in the world. Yet, the SSP citrus industry has been, and still is, under constant attack from various diseases. In the 1940s, tristeza-quick decline (T-QD) was responsible for the death of 9 million trees in SSP. The causal agent was a new virus, citrus tristeza virus (CTV). The virus was efficiently spread by aphid vectors, and killed most of the trees grafted on sour orange rootstock. Control of the disease resided in replacing sour orange by alternative rootstocks giving tolerant combinations with scions such as sweet orange. Because of its drought resistance, Rangpur lime became the favourite alternative rootstock, and, by 1995, 85% of the SSP sweet orange trees were grafted on this rootstock. Therefore, when in 1999, many trees grafted on Rangpur lime started to decline and suddenly died, the spectre of T-QD seemed to hang over SSP again. By 2003, the total number of dead or affected trees was estimated to be over one million. The new disease, citrus sudden death (CSD), resembles T-QD in several aspects. The two diseases have almost the same symptoms, they spread in time and space in a manner strikingly similar, and the pathological anatomy of the bark at the bud union is alike. Transmission of the CSD agent by graft-inoculation has been obtained with budwood inoculum taken not only on CSD-affected trees (grafted on Rangpur lime), but also on symptomless trees (grafted on Cleopatra mandarin) from the same citrus block. This result shows that symptomless trees on Cleopatra mandarin are tolerant to the CSD agent. Trees on rootstocks such as Sunki mandarin or Swingle citrumelo are also tolerant. Thus, in the CSD-affected region, control consists in replacing Rangpur lime with compatible rootstocks, or in approach-grafting compatible rootstock seedlings to the scions of trees on Rangpur lime (inarching). More than 5 million trees have been inarched in this way. A new disease of sweet orange

  20. 76 FR 78228 - Notice of Request for Extension of Approval of an Information Collection; Citrus Greening and...

    Science.gov (United States)

    2011-12-16

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

  1. Integrated Management of Major Citrus Pests and Diseases in Guangxi%广西柑橘主要病虫害及其防治措施

    Institute of Scientific and Technical Information of China (English)

    廖贤军; 冷付春; 陈国平; 牛英; 刘冰浩; 娄兵海

    2012-01-01

    介绍了广西柑橘主要病虫害种类,分析了危害状况,提出了防治措施。%In order to provide guidance forcitrus production, this paper introduced the serious situation and the control tactics for the major pests and diseases of citrus orchard in Guangxi.

  2. Java project on periodontal diseases: effect of vitamin C/calcium threonate/citrus flavonoids supplementation on periodontal pathogens, CRP and HbA1c

    NARCIS (Netherlands)

    A. Amaliya; M.L. Laine; B.G. Loos; U. van der Velden

    2015-01-01

    Objective To assess in a periodontally diseased rural population deprived from regular dental care and having poor dietary conditions, the effect of vitamin C/calcium threonate/citrus flavonoids (VitC/Ca/Fl) supplementation on subgingival microbiota and plasma levels of vitamin C, HbA1c and hsCRP. M

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

    Science.gov (United States)

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

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

    Directory of Open Access Journals (Sweden)

    Dilli Prasad Paudyal

    2015-12-01

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

    2010-05-26

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

  7. 采后贮藏环境诱导柑橘果皮油胞病的发病机制%Oleocellosis Mechanism of Postharvest Citrus Peel Induced by Storage Conditions

    Institute of Scientific and Technical Information of China (English)

    刘丽丹; 曾凯芳

    2012-01-01

    柑橘在采后贮藏期间由于贮藏环境的变化很容易诱导其果皮产生油胞病,贮藏环境的影响因素主要有贮藏温度、相对湿度及气体水平。过高或者过低的贮藏温度,以及温度的波动都会影响果皮的抗氧化活性系统及水分的迁移,从而加速柑橘果皮油胞病的发病。不适宜的贮藏相对湿度通过影响果皮水分散失,改变果皮水位导致白皮层脱水,进而诱导柑橘果皮油胞病的发生。低O2高C02的气体水平影响柑橘果实呼吸作用及其他生理代谢,造成果实皮层水分及膜脂的变化,引起柑橘果皮油胞病的发病加剧。本文通过介绍贮藏条件对柑橘果皮油胞病发病机制的影响,为进一步深入了解柑橘果皮油胞病的发病原因、发病机理以及控制措施提供理论依据。%Oleocellosis, a physiological disorder of citrus fruits, can be easily induced by changes in storage conditions such as storage temperature, relative humidity (RH) and gas level. Meanwhile, oleocellosis can also be aggravated by too high or too low storage temperature and fluctuated storage temperature, thus affecting antioxidant activity and water transportation. In addition, inappropriate relative humidity can result in water loss in fruits, which can cause albedo dehydration due to altered water potential in the albedo of citrus fruits and corresponding occurrence of oleoceUosis in citrus peel. Moreover, oleocellosis also can be induced by low 02 and high CO2 level, thereby resulting in an obvious change in respiration intensity and other physiological metabolisms of citrus as well as changes in water content and cell membrane lipid of citrus peel. In this article, the effects of storage conditions on the pathogenesis of oleocellosis are discussed, which will provide a theoretical support for a thorough understanding of the causes, mechanisms and control strategies of oleocellosis.

  8. Advances in Biological Control of Citrus Psyllid Diaphorina citri, a Vector Insect of Citrus Huanglongbing Disease%黄龙病媒介昆虫柑橘木虱生物防治新进展

    Institute of Scientific and Technical Information of China (English)

    代晓彦; 任素丽; 周雅婷; 任顺祥; 邱宝利

    2014-01-01

    The citrus psyllid, Diaphorina citri Kuwayama, is the primary vector of citrus Huanglongbing disease, Candidatus Liberibacter asiaticus, which has the huge potential threats to the development of citrus industry in China. Based on the comprehensive understanding of D. citri control technologies, we reviewed the latest advances in biological control of D. citri and forecasted its future prospects. The main biological control resources of citrus psyllid currently are natural enemy insects and entomopathogenic fungi, among which predatory ladybeetles, lacewings, spiders and hover flies are the dominant species of predator, while Tamarixia radiata and Diaphorencyrtus aligarhensis are the two dominant parasitoids in China. Several representative entomopathogenic fungi include Lecanicillium lecanii, Isaria fumosorosea, Beauveria bassiana and Hirsutella citriformis have been reported with high virulence to citrus psyllid. This current review is expected to provide technical support and theoretical reference for efficient and sustainable control of citrus psyllid in the future.%柑橘木虱Diaphorina citri Kuwayama是柑橘黄龙病的重要媒介昆虫,对我国柑橘产业的健康发展潜在着巨大的威胁。本文在综合国内柑橘木虱防控技术的基础上,对近年来柑橘木虱生物防治的最新研究进展进行了综述,并且对其生物防治的发展前景给予了展望。目前应用于柑橘木虱生物防治的天敌资源主要是天敌昆虫及昆虫病原真菌,其中捕食性天敌主要包括瓢虫、食蚜蝇、草蛉和蜘蛛,寄生性天敌昆虫主要包括啮小蜂和跳小峰;昆虫病原真菌主要包括蜡蚧轮枝菌、拟青霉、白僵菌、桔形被毛孢等。期望通过对柑橘木虱生物防治工作的综述,为我国今后柑橘木虱的科学、高效防控及其可持续治理提供参考,不断推动我国柑橘产业的健康发展。

  9. Recent advances in Citrus psorosis virus

    OpenAIRE

    Achachi, Asmae; Ait Barka, Essaïd; Ibriz, Mohammed

    2014-01-01

    Psorosis is a globally devastating disease of citrus caused by an infectious filamentous ophiovirus, Citrus psorosis virus (CPsV), which causes annual losses of about 5 % and a progressive decline of trees by affecting the conductive tissues. The disease can be harboured asymptomatically in many citrus species. In the field, the most characteristic symptoms of the disease in adult trees are bark scaling in the trunk and main branches and also internal staining in the underlying wood. The viru...

  10. Determination and control of the main pathogens of post-harvest fruit and vegetables rot disease in Ningxia%果蔬采后致腐病菌检测及防治

    Institute of Scientific and Technical Information of China (English)

    顾沛雯; 张光弟; 王华荣; 丁波

    2012-01-01

    It was showed that the main pathogens of post-harvest fruit and vegetables rot disease postharvest fruit and vegetables rot disease were Botrytis, Aspergillus, Penicillium, Rhizopus and Alternaria through isolating, purifing, pathogenicity determination, identification and ways of infection in Ningxia. Among these pathogens, Aspergillus sp. and Rhizopus sp. were the chief pathogens during post-harvest transportation and marketing because they cause rot disease during high temperature, yet Botrytis sp. , Alternaria sp. , and Penicillium sp. were the major pathogens during transportation and storage under 10-15℃. Through two preservation tests of post-harvest fruit and vegetables with 2-butanamine fumigating and chlorine dioxide immersing, it is showed that combination of low temperature and antistaling agent can obviously prolong 9-11 days delivery period and shelf life.%引起果蔬采后腐烂的病原菌主要分属于葡萄孢属(Botrytis)、曲霉属(Aspergillus)、青霉属(Penicillium)、根霉属(Rhizopus)和链格孢属(Alternaria).其中A.sp.和R.sp.是果蔬常温运输过程中的主要致腐菌,B.sp.、A.sp.和P.sp.是果蔬低温贮运条件下的主要致腐菌.采用仲丁胺和二氧化氯2种药剂对采后蔬菜进行熏蒸和浸泡保鲜处理.结果表明:低温与保鲜剂处理相结合,可明显提高果蔬采后运输及货架期9~11d.

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

    Science.gov (United States)

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

    2014-06-01

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

  12. A transcriptomic approach highlights induction of secondary metabolism in citrus fruit in response to Penicillium digitatum infection

    OpenAIRE

    González-Candelas Luis; Alamar Santiago; Sánchez-Torres Paloma; Zacarías Lorenzo; Marcos Jose F

    2010-01-01

    Abstract Background Postharvest losses of citrus fruit due to green mold decay, caused by the fungus Penicillium digitaum, have a considerable economic impact. However, little is known about the molecular processes underlying the response of citrus fruit to P. digitatum. Results Here we describe the construction of a subtracted cDNA library enriched in citrus genes preferentially expressed in response to pathogen infection followed by cDNA macroarray hybridization to investigate gene expressi...

  13. BABA处理提高采后砂糖桔对青霉菌的抗病性%Postharvest BABA treatment induces resistance of mandrin(Citrus Reticulata Blancdo cv.Shiyueju)fruit to Penicillium digitatum

    Institute of Scientific and Technical Information of China (English)

    汪跃华; 徐兰英; 庞学群; 张昭其

    2011-01-01

    诱导抗病性是水果采后病害生物防治的重要内容之一.对非呼吸跃变型的砂糖桔(Citrus Reticulata Blancdo Cv.Shiyueju)果实进行BABA渗透处理后接种绿霉病菌孢子,结果表明:不同浓度 BABA处理果实的发病率和病斑面积均比对照果实的低,其中0.5g/L BABA处理效果最好,BABA处理提高了沙糖桔果实CHT、GUN、PAL、PPO、POD活性,提高了果皮H2O2含量.

  14. 怀集县柑桔黄龙病的普遍发生及防控对策%Widespread Occurrence of Citrus Yellow Shoot Disease in Huaiji County and Control Measures

    Institute of Scientific and Technical Information of China (English)

    谭加年; 朱宝珍

    2011-01-01

    目前怀集县柑桔园普遍发生黄龙病,并且有越来越严重的趋势,对柑桔生产已构成严重威胁。如何有效地控制黄龙病的发生为害成为柑桔生产上的重要课题。简述了怀集县柑桔黄龙病的发生状况,分析了柑桔黄龙病普遍发生的原因,提出了切实可行的防控措施。%Citrus yellow shoot disease are wide spreading in citrus plantations of Huaiji County and more and more serious, which is a serious threat to citrus production. How to effectively control citrus yellow shoot disease becomes an important task in citrus production. The situation of citrus yellow shoot disease in Huaiji County is sketched. The cause of widespread occurrence of citrus yellow shoot disease is analyzed. Control measures are put forward.

  15. A Novel Study of Interactions of Arabidopsis thaliana With Candidatus Liberibacter psyllaurous When Transmitted by psyllid Bactericera cockerelli to Develop a Chemical Genomics Based Approach That can aid in Development of Control Strategies for Huanglongbing Disease in Citrus

    OpenAIRE

    Zadgaonkar, Sai

    2015-01-01

    Huanglongbing (HLB) is a bacterial disease associated with Candidatus Liberibacter asiaticus (CLas), Candidatus Liberibacter americanus, and Candidatus Liberibacter africanus. These bacterial species are transmitted by hemipteran psyllids. For many years, this disease has caused substantial damage to citrus around the world and in recent years, it has significantly impacted citrus production in the U.S.A. The lack of effective control and curative measures against psyllids and the pathogen ar...

  16. Identification of a single-stranded DNA virus associated with citrus chlorotic dwarf disease, a new member in the family Geminiviridae.

    Science.gov (United States)

    Loconsole, Giuliana; Saldarelli, Pasquale; Doddapaneni, Harshavardhan; Savino, Vito; Martelli, Giovanni P; Saponari, Maria

    2012-10-10

    In the attempt to identify the causal agent of Citrus chlorotic dwarf disease (CCDD), a virus-like disorder of citrus, the small RNA fraction and total DNA from symptomatic citrus plants were subjected to high-throughput sequencing. DNA fragments deriving from an apparently new geminivirus-like agent were found and assembled by NGS to re-construct the entire viral genome. The newly identified virus has a circular single-stranded DNA genome comprising five open reading frames (ORFs) with sequence homologies with those encoded by geminiviruses. PCR and qPCR assays were successfully used for determining its presence in the CCDD-affected plants obtained by graft propagation. The larger genome size (3.64 vs. 2.5-3.0 kb) and a number of differences in its structural organization, identified this virus as a highly divergent member of the family Geminiviridae, to which the provisional name of Citrus chlorotic dwarf-associated virus (CCDaV) is assigned.

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

  19. Disrupt the bacterial growth in the insect vector to block the transmission of Candidatus Liberibacter asiaticus to citrus, the causal agent of citrus greening disease

    OpenAIRE

    Killiny, N.; Hajeri, S.; Gowda, S.; Davis, M. J.

    2014-01-01

    The genome of Candidatus Liberibacter asiaticus (CLas) reveals the presence of luxR, encodingLuxR protein, one of a two component cell-to-cell communication system. However, the genome lacks the second component, luxl, that produces acyl-homoserine lactones (AHLs), suggesting that CLas has a solo LuxR system. Interestingly, we detected compounds that may act as AHLs in the insect vector (psyllids) that are healthy or infected with CLas, but not in the citrus plants. This finding suggests that...

  20. Imazalil residue loading on citrus fruit as affected by formulation, solution pH and exposure time in aqueous dip treatments

    Science.gov (United States)

    Green mould caused by Penicillium digitatum is responsible for major postharvest fruit losses on the South African fresh citrus export market. Some of these losses, as well as fungicide resistance development, can be attributed to sub-optimal imazalil (IMZ) residue loading on citrus fruit, i.e. <2 µ...

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

    OpenAIRE

    Neelam Mallick; Rafeeq Alam Khan

    2016-01-01

    Objective: Hyperlipidemia, extensively contributes in the progression of coronary heart diseases and atherosclerosis, but may be managed through alterations in the nutritional pattern. Several studies show that diet rich in polyphenols and antioxidants have antiatherogenic effects. Citrus sinensis and Citrus paradisi are widely known for health benefits and have found to produce antioxidant, anti-inflammatory, and hypolipidemic effects, hence current research was planned to determine the hypo...

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

    2011-11-01

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

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

    Science.gov (United States)

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

    2014-03-01

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

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

    Science.gov (United States)

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

    2014-03-01

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

  6. Epidemic and research advance of Citrus Black Spot%柑橘黑斑病(Citrus Black Spot)发生危害现状和研究进展

    Institute of Scientific and Technical Information of China (English)

    王兴红; 陈国庆; 王卫芳; 李红叶

    2011-01-01

    柑橘黑斑病(Citrus Black Spot,CBS)主要危害果实,在果皮上形成各种病斑而影响果实的外观品质和销售价格,严重时可造成田间落果和贮藏期果实腐烂。同时,黑斑病被欧盟列为A1类外来有害生物,美国对此也有严格的限制。因此,该病害影响柑橘鲜果的国际贸易。黑斑病的病原属球座菌(Guignardia),其无性态为叶点霉菌(Phyl-losticta)。宽皮柑橘(Citrus reticulata)、橙类(C.sinensis)和柠檬(C.limon)上为柑橘球座菌(G.citricarpa),无性态为%Citrus Black Spot(CBS) attacks citrus fruits,produces various spots on citrus rind,gives rise to the decrease in external quality and commercial value.It causes immature fruit-dropping in fields or postharvest decaying in storage houses when disease occurs severely.Meanwhile,CBS is regulated as an A1 quarantine pest by several countries of European Union,as well as USA,so international trade of fresh citrus is restricted by this disease.The causal agents of CBS belong to genus Guignardia(anamorph Phyllosticta).G.citricarpa(anamorph P.citricarpa) is responsible to the CBS of mandarins(C.reticulata),oranges(C.sinensis) and lemon(C.limon),whereas P.citriasiana(teleomorph unknown) is responsible to tan spot of pomeloes(C.grandis).In addition,an endophyte,P.capitalensis is commonly present on citrus,which often interferes the detection of CBS.CBS is a common disease in China,significant losses often be leaded to some susceptible varieties.However,the knowledge of CBS is handful in China.To satisfy the requirement of broad readers to full scenario of CBS,in current paper,we integrate the published information of inter-and intra-nation regarding CBS,and give a detail introduction on the aspects of disease history,distribution,significance,symptom,etiology,prevalence,detection control,etc.

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

    Science.gov (United States)

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

    2016-08-01

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

  8. Antagonism of local isolates of Trichoderna spp.on citrus root rot disease by Fusarium solani in the mekong delta of vietnam

    Institute of Scientific and Technical Information of China (English)

    Duong Minh; Jozef Coosemans; Le Lam Cuong; Ester Vandersmissen; Pham Van Kim

    2004-01-01

    @@ The local isolates of Trichoderrma spp. and Fusariun solani were colected from citrus orchards in the Mekong delta of Vietnam and isolated on PDA, PDB and TSM medium for antagonism and Koch's postulate testing. The results showed that the high chitinolytic enzymes content of Trichoderma isolates can antagonise with Fusarium solani isolates by preventing the germination of Fusarium macroconidia in in-vitro condition. There are five promising isolates of Trichoderna spp. having high antagonism with Fusarium solani. These Trichoderma isolates also grew well in rice straws, maize stems, weeds and water hyacinth biowaste materials. These results supply the promising trend for biological control of root rot disease on citrus orchards of the Mekong delta.

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

    Directory of Open Access Journals (Sweden)

    José Luis Cruz-Jaramillo

    2014-07-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    2014-07-07

    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.

  11. Susceptibility of sixteen citrus genotypes to Candidatus Liberibacter asiaticus

    Science.gov (United States)

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

  12. Detection of a new medium for budwood culture in vitro of citrus

    OpenAIRE

    SERTKAYA, Gülşen ŞAŞ; ÇINAR, Ahmet

    1998-01-01

    The transfer of new and quality citrus species and cultivars from one country or growing area to another may lead to the introduction of new pests and diseases. Therefore the import and direct production of citrus budwood without adequate control measures has a high risk. The citrus virus and virus-like disease agents can be successfully eliminated using the shoot-tip grafting (STG) technique which is routinely used to obtain virus-free plants in citrus improvement programs in major citrus...

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

    Science.gov (United States)

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

  14. Autologistic model with an application to the citrus "sudden death" disease Modelo autologístico com aplicação para a doença "morte súbita" dos citrus

    Directory of Open Access Journals (Sweden)

    Elias Teixeira Krainski

    2008-01-01

    Full Text Available The citrus sudden death (CSD disease affects dramatically citrus trees causing a progressive plant decline and death. The disease has been identified in the late 90's in the main citrus production area of Brazil and since then there are efforts to understand the etiology as well as the mechanisms its spreading. One relevant aspect of such studies is to investigate spatial patterns of the occurrence within a field. Methods for determining whether the spatial pattern is aggregated or not has been frequently used. However it is possible to further explore and describe the data by means of adopting an explicit model to discriminate and quantify effects by attaching parameters to covariates which represent aspects of interest to be investigated. One alternative involves autologistic models, which extend a usual logistic model in order to accommodate spatial effects. In order to implement such model it is necessary to take into account the reuse of data to built spatial covariates, which requires extensions in methodology and algorithms to assess the variance of the estimates. This work presents an application of the autologistic model to data collected at 11 time points from citrus fields affected by CSD. It is shown how the autologistic model is suitable to investigate diseases of this type, as well as a description of the model and the computational aspects necessary for model fitting.A morte súbita dos citros (MSC é uma doença com efeitos dramáticos em árvores de citros causando declínio progressivo e morte. Ela foi identificada no final da década de 90 em uma das principais áreas de produção no Brasil e desde então esforços são empregados para entender a sua etiologia e os seus mecanismos de dispersão. Um aspecto relevante para estudos é a investigação do padrão espacial da incidência dentro de um campo. Métodos para determinar se o padrão espacial é agregado ou não têm sido freqüentemente utilizados. Entretanto é poss

  15. 75 FR 28233 - Availability of an Environmental Assessment for a Biological Control Agent for Asian Citrus Psyllid

    Science.gov (United States)

    2010-05-20

    .... ] ACP is of particular concern since it is a carrier of Huanglongbing disease (citrus greening), which is considered to be one of the most serious citrus diseases in the world. Citrus greening is a... Control Agent for Asian Citrus Psyllid AGENCY: Animal and Plant Health Inspection Service, USDA....

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

    OpenAIRE

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

    2015-01-01

    In an earlier study, an electronic tongue system (e-tongue) has been used to differentiate between orange juice made from healthy fruit and from fruit affected by the citrus greening or Huanglongbing (HLB) disease. This study investigated the reaction of an e-tongue system to the main chemicals in orange juice that impact flavor and health benefits and are also impacted by HLB. Orange juice was spiked with sucrose (0.2–5.0 g/100 mL), citric acid (0.1%–3.0% g/100 mL) and potassium chloride (0....

  17. Variation in flavonoid levels in Citrus benikoji Hort. ex. Tan. infected by Colletotrichum gloeosporioides.

    Science.gov (United States)

    Jeong, Sung Woo; Kim, Hae Gyeong; Park, Semin; Lee, Jung Han; Kim, Yun-Hi; Kim, Gon-Sup; Jin, Jong Sung; Kwak, Youn-Sig; Huh, Moo Ryong; Lee, Ji Eun; Song, Yi; Shin, Sung Chul

    2014-04-01

    Anthracnose caused by Colletotrichum gloeosporioides is one of the most serious postharvest diseases of citrus fruit. Fruit peels infected with C. gloeosporioides and the peels of healthy fruit were analysed for flavonoids, using high performance liquid chromatography-tandem mass spectroscopy, to evaluate variations in flavonoid levels in Citrus benikoji Hort. ex. Tan. Seventeen flavonoids were characterised from the fruit peels. The flavonoids were validated using structurally related standards and quantified. Among the 17 flavonoids, the concentration of component 3 was the highest and that of component 10 was the lowest. During 8 days after inoculation, the concentration of the seven flavonoids 1-3, 5, 6, 13, and 14 increased gradually up to day 8. Flavonoid 4 was detected from day 7. The seven minor flavonoid components, 8-12, 15, and 16 increased to day 5 and then decreased. However, flavonoids level variations were not significantly different from that of the non-infected fruits during the experimental period. The monitoring suggested that the constitutively formed seven polymethoxyflavones (8-12, 15, and 16) may act as phytoanticipins in the defence mechanism against the fungus, and that hespertin 7-O-glucoside (4), produced de novo on day 6 after infection, may function as a phytoalexin.

  18. Postharvest treatments of fresh produce

    OpenAIRE

    Mahajan, P. V.; Caleb, O. J.; Z. Singh; Watkins, C. B.; M. Geyer

    2014-01-01

    Postharvest technologies have allowed horticultural industries to meet the global demands of local and large-scale production and intercontinental distribution of fresh produce that have high nutritional and sensory quality. Harvested products are metabolically active, undergoing ripening and senescence processes that must be controlled to prolong postharvest quality. Inadequate management of these processes can result in major losses in nutritional and quality attributes, outbreaks of foodbo...

  19. Sweetpotato post-harvest assessment

    OpenAIRE

    Rees, Debbie; Van Oirschot, Quirien; Kapinga, Regina

    2003-01-01

    For any crop cultivar to be successful it must not only have good production characteristics but also characteristics that ensure the harvested crop is acceptable and suitable for its intended use. Sweetpotato Post-harvest Assessment summarizes work carried out on postharvest aspects of sweetpotato between 1994 and 2002 within collaborative projects involving the Natural Resources Institute (UK), the International Potato Center and the Tanzanian Ministry of Agriculture, with input from the Ke...

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

    Science.gov (United States)

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

    2013-01-15

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

  1. 柑橘黄龙病发病机理、症状及防控措施%Citrus Yellow Dragon Disease Pathogenesis, Symptoms and Prevention Measures

    Institute of Scientific and Technical Information of China (English)

    邱志燏; 黄红兰; 舒畅; 邱俊洁

    2015-01-01

    The disease pathogenesis of Citrus Huanglong is that Huanglong pathogen transmits to roots through the vascular bundles, then damages the roots, and causes root rot. The plants cannot discharge metabolic wastes produced from plant circulation disorder from the root, causing lesions. Like a sieve catheter jam, root rot is the direct symptom of Huanglong bacteria harmful to citrus, while the secondary symptom is on citrus canopy. The secondary symptom is caused by a lack of food and water, so, the supplementation of sufficient nutrients and moisture can make the plant back to normal condition. Although the rotten roots cannot be cured, the root will grow, become normal and new roots, making the plant grow normally. Therefore, citrus Huanglong disease and its symptoms on the ground can be cured.%柑橘黄龙病由黄龙病菌通过维管束传输至根,为害根,造成根腐烂,进而导致根不能从土壤中吸收养分和水分,植物代谢废物不能从根系排出,产生植物汁液循环障碍,叶片和果实因缺乏养分和水分而产生病变。根腐烂是黄龙病菌危害柑橘的直接症状,叶片和果实表现为次生症状,次生症状是缺乏养分和水分所致。病发后采取每周喷施“果无缺”加施多元素叶面肥,试验表明,黄龙病黄化叶会转绿,黄龙病青果也会转变为正常果。研究还发现,腐烂的根虽然不能恢复正常,但根还会生长,进而形成正常的新的根系,使植株重新正常生长。

  2. 植物精油防控果蔬采后病害的应用探究%Inquiry on Application of Botanical Essential Oils in Prevention and Control of Fruits and Vegetables' Postharvest Diseases

    Institute of Scientific and Technical Information of China (English)

    薛山; 谭谊谈

    2011-01-01

    The production and marketing of domestic fruit and vegetable was one the most-impact in the world.While fruits and vegetables were satisfying the people's needs,it also faced to a severe problem of storage.As a natural preservative from plant,the tapping and applying of this essential oil-preservation had gained widely attention.The essential oils were mainly extracted from the flowers,leaves,stems,roots or fruits of spice and herbal plants,which had significant antibacterial effect.Therefore,the essential oils were widely used in the defense of postharvest diseases of fruits and vegetables.At present,the study on the essential oil and its antimicrobial components in the postharvest storage had made some achievements in the country.However,compared with the foreign research,the domestic were relatively unenlightened.This article aims to provide theoretical basis and practical reference on the killing of pathogenic microbes and prevention of physiological of disease during the postharvest storage of fruits and vegetables.%我国是世界果蔬产销大国之一。果品蔬菜在满足人们需求的同时,也面临着严峻的贮藏问题。作为一种天然植物源保鲜剂,精油类果蔬防腐保鲜剂的研发与应用广受关注。植物精油多提取于香辛料及中草药植物的花、叶、茎、根或果实,具有显著的抑菌效果,因而被广泛用于果蔬采后病害的防控。目前,精油及其抑菌成分在国内果蔬采后贮藏的应用研究已取得了一定的成效,但较之国外的研究还相对落后。该文依据国外内最新的研究动态,通过综述精油的植物源种类、应用现状趋势的最新研究进展,以期为果蔬采后病原微生物的抑杀和生理性病害的防控提供理论基础和实践参考。

  3. Biocontrol of Postharvest Anthracnose of Mango Fruit with Debaryomyces Nepalensis and Effects on Storage Quality and Postharvest Physiology.

    Science.gov (United States)

    Luo, Shanshan; Wan, Bin; Feng, Shuhan; Shao, Yuanzhi

    2015-11-01

    Anthracnose is presently recognized as one of the most important postharvest disease of mango worldwide. To control the disease, chemical fungicides for a long time was widely used among fruit farmers, but recently found that pathogen had developed increasingly resistance to it. With people's growing desire of healthy and green food, finding new and environmentally friendly biological control approach was very necessary. In this paper, we provided a kind of new antagonistic yeast which enriched the strain resources and the efficacy of Debaryomyces nepalensis against postharvest anthracnose of mango fruit and the influence on quality parameters were investigated. The results showed that the decay incidence and lesion diameter of postharvest anthracnose of mango treated by D. nepalensis were significantly reduced compared with the control fruit stored at 25 °C for 30 d or at 15 °C for 40 d, and the higher concentration of D. nepalensis was, the better the efficacy of the biocontrol was. Study also found that 1 h was the best treatment duration and antagonistic yeast inoculated earlier had good biocontrol effect on anthracnose. Meanwhile, treatment by D. nepalensis could significantly reduce postharvest anthracnose of mango, delay the decrease in firmness, TSS, TA, and ascorbic acid value, and do not impair surface color during postharvest storage. Moreover, the increase in MDA (malondialdehyde) content and increase in cell membrane permeability of fruit treated by D. nepalensis was highly inhibited. The results suggested D. nepalensis treatment could not only maintain storage quality of mango fruit, but also decrease the decay incidence to anthracnose disease. All these results indicated that D. nepalensis has great potential for development of commercial formulations to control postharvest pathogens of mango fruit.

  4. Advance in Research on Biological Control of Postharvest Diseases of Fruits and Vegetables by Bacillus amyloliquefaciens%解淀粉芽孢杆菌防治果蔬采后病害研究进展

    Institute of Scientific and Technical Information of China (English)

    洪鹏; 安国栋; 胡美英; 王会冬

    2013-01-01

    综述了解淀粉芽孢杆菌在果蔬采后病害防治上的应用及研究进展,归纳了解淀粉芽孢杆菌的筛选途径和研究现状,总结了解淀粉芽孢杆菌的控病作用机制和提高解淀粉芽孢杆菌作用效果的方法;指出解淀粉芽孢杆菌用于果蔬保鲜存在的诸如防效不稳定和商业化困难等问题,并提出与低量化学药剂混用和运用分子生物学手段研究抑菌机理等建议;最后,认为以解淀粉芽孢杆菌为主要成分的生物农药具有广阔的应用前景.%The research advance of using Bacillus amyloliquefaciens to postharvest diseases of fruits and vegetables was reviewed, including the screening methods antagonists and situation of B.amyloliquefaciens. The mechanisms of the antagonist B. amyloliquefaciens against postharvest diseases of fruits and vegetables and improved ways of antagonistic microorganism were summarized. Moreover, the paper also presented the application of B. amyloliquefaciens agent and the existing problems such as instability of control effect and difficulty of commercialization, combined use of pesticides and using methods in molecular biology on bacteriostasis mechanism are propounded. Finally, the pesticides of B. amyloliquefaciens were considered as wide development prospect in the future.

  5. Postharvest Decay of Apples and Pears in The Netherlands

    NARCIS (Netherlands)

    Wenneker, M.; Köhl, J.

    2014-01-01

    Postharvest diseases are a major problem in long storage of apples and pears in The Netherlands. Despite intensive preharvest spraying programs significant losses occur (over 60% of fruit losses are recorded). Over 125 heavily affected lots of apples (mainly ‘Elstar’) and pears (mainly ‘Conference’)

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

    OpenAIRE

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

    2014-01-01

    Background Transcriptional activator-like (TAL) effectors, formerly known as the AvrBs3/PthA protein family, are DNA-binding effectors broadly found in Xanthomonas spp. that transactivate host genes upon injection via the bacterial type three-secretion system. Biologically relevant targets of TAL effectors, i.e. host genes whose induction is vital to establish a compatible interaction, have been reported for xanthomonads that colonize rice and pepper; however, citrus genes modulated by the TA...

  7. 75 FR 34419 - Notice of Revision and Request for Extension of Approval of an Information Collection; Citrus...

    Science.gov (United States)

    2010-06-17

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

  8. Transcriptomic profiling of citrus fruit peel tissues reveals fundamental effects of phenylpropanoids and ethylene on induced resistance

    NARCIS (Netherlands)

    Ballester Frutos, A.R.; Lafuente, M.T.; Forment, J.; Gadea, J.; Vos, de C.H.R.; Bovy, A.G.; Gonzalez-Candelas, L.

    2011-01-01

    Penicillium spp. are the major postharvest pathogens of citrus fruit in Mediterranean climatic regions. The induction of natural resistance constitutes one of the most promising alternatives to avoid the environmental contamination and health problems caused by chemical fungicides. To understand the

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

  14. Citrus breeding, genetics and genomics in Japan.

    Science.gov (United States)

    Omura, Mitsuo; Shimada, Takehiko

    2016-01-01

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

  15. Citrus breeding, genetics and genomics in Japan.

    Science.gov (United States)

    Omura, Mitsuo; Shimada, Takehiko

    2016-01-01

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

  16. Progress on Dissecting and Controlling the Citrus Huanglongbing Complex

    OpenAIRE

    Duan, Yongping; Zhou, Lijuan; Zhang, Muqing; Benyon, Lesley; Armstrong-Vahling, Cheryl; Hoffman, Michele; Hao, Guixia; Zou, Huasong; Doud, Melissa; Ding, Fang; Morgan, Kent

    2014-01-01

    Citrus huanglongbing (HLB) is a century-old and emerging disease that impedes citrus production worldwide. ‘Candidatus Liberibacter asiaticus’ (Las) is the globally prevalent species of HLB bacteria. Here we describe our molecular characterizations of Las, and our newly-developed control methods for citrus HLB. From a genomics standpoint, we revealed Las has a significantly reduced genome (1.26Mb) and unique features adapted to its intracellular life style.  Although the genome is small, Las ...

  17. Potential applications of ionizing radiation in postharvest handling of fresh fruits and vegetables

    International Nuclear Information System (INIS)

    The advantages and limitations of potential uses of ionizing radiation of harvested fresh fruits and vegetables are discussed. Potential applications include: sprout inhibition of tuber, bulb, and root vegetables; inhibition of post-harvest growth of asparagus and mushrooms; insect disinfestation; alteration of ripening and senescence in fresh fruits; and post-harvest microorganism disease control. Cost, consumer acceptance, and logistical problems are cited as possible limiting factors. Factors influencing response also are discussed

  18. Early detection of fungal disease infection in strawberry fruits by e-nose during postharvest storage%电子鼻对草莓采后贮藏早期霉菌感染的检测

    Institute of Scientific and Technical Information of China (English)

    朱娜; 毛淑波; 潘磊庆; 袁丽佳; 屠康

    2013-01-01

      为了实现电子鼻对草莓贮藏期常见霉菌感染的早期检测,对草莓果实分别接种灰霉、扩展青霉和根霉3种主要病原菌,以无菌水处理为对照组,每2 d采用PEN3电子鼻获取草莓的气味,并用气质联用技术分析草莓气味.结果表明,草莓接种病原菌2 d后,主成分分析能够正确区分正常果实(对照组)与病害果实,且可以较好区分草莓感染病原菌种类,多元方差分析结果也显示接种不同病原菌对草莓果实挥发性物质的影响差异显著(P<0.05),通过 Fisher 判别建立的回归函数对3种病原菌灰霉、扩展青霉和根霉及对照组的判别正确率分别为100%、93.3%、86.7%和100%.载荷分析及气质联用技术结果表明病原菌对草莓果实挥发性物质的影响主要体现在烃类及酯类的变化.研究结果可为实现草莓采后贮藏和流通过程中质量变化和病原微生物的感染进行无损快速检测和监测提供参考.%Strawberry postharvest diseases usually cause heavy losses in storage. Electronic nose (PEN3) containing an array of 10 different metal oxide sensors was used to detect and classify three kinds of common postharvest fungal diseases of strawberry fruit:Botrytis sp. (BC), Penicillium sp. (PE) and Rhizopus sp. (RH) in this paper. Ripe strawberry fruits were inoculated individually with the three pathogens and non-inoculated samples with sterile water treatment as control. Volatile compounds emanating from strawberry fruit were assessed using PEN3 every two days after inoculation. On the second day after invocation, the principal component analysis (PCA) of volatile profiles can clearly distinguish between normal and infection strawberry fruit; Furthermore, it can discriminate three groups of strawberry fruit with different pathogenic bacteria. Multivariate analysis of variance (MANOVA) was conducted on the e-nose sensors’response to the strawberry fruit with different treatment on

  19. Pest control in postharvest nuts

    Science.gov (United States)

    This chapter discusses the impact of insect infestations on the quality of postharvest nuts. The chapter first reviews the biology of key field pests that may be found in harvested nuts, and pests found in nut storage and processing facilities. The chapter then reviews current and developing control...

  20. Reasoned opinion on the modification of the existing MRLs for propiconazole in citrus fruits

    OpenAIRE

    European Food Safety Authority

    2012-01-01

    In accordance with Article 6 of Regulation (EC) No 396/2005, Spain, herewith referred to as the evaluating Member State (EMS), received an application from Makhteshim Agan España S.A. to modify the existing MRL for the active substance propiconazole in citrus fruits. In order to accommodate for the intended post-harvest use of propiconazole, the EMS proposed to raise the existing MRL in citrus fruit from the limit of quantification (0.05 mg/kg) to 5 mg/kg. According to EFSA the data are suffi...

  1. Preliminary study on the species and distribution of citrus pests and diseases in Shanghai%上海市柑橘病虫害的种类和分布调查初报

    Institute of Scientific and Technical Information of China (English)

    成玮; 蒋飞; 武向文; 郭玉人; 王玉香; 陆爽; 陶赛峰

    2015-01-01

    连续数年对上海市柑橘树病虫害进行普查,共发现病虫害91种,包括病害18种、昆虫纲66种、蛛形纲等其他有害生物7种;并从发生程度、分布和危害等方面对上海市柑橘病虫害发生的历史资料进行了分析,基本摸清了上海市柑橘病虫害发生现状。%A survey of citrus pests and diseases in Shanghai area was carried out for several years.91 kinds of pests and diseases were found,including 18 species of diseases,66 species of insects,7 species of Arachnids and other pests.The historical data of citrus pests and diseases in Shanghai was analyzed from the occurrence de-gree,distribution and damage and so on.The status of citrus pests and diseases in Shanghai area was basically found out.

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

    Science.gov (United States)

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

  3. 78 FR 58992 - Notice of Request for Extension of Approval of an Information Collection; Citrus Canker...

    Science.gov (United States)

    2013-09-25

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

  4. 7 CFR 457.107 - Florida citrus fruit crop insurance provisions.

    Science.gov (United States)

    2010-01-01

    ... individual citrus fruit from Citrus IV, V, VII, and VIII to be unmarketable as fresh fruit; or (7) Diseases... 7 Agriculture 6 2010-01-01 2010-01-01 false Florida citrus fruit crop insurance provisions. 457... INSURANCE CORPORATION, DEPARTMENT OF AGRICULTURE COMMON CROP INSURANCE REGULATIONS § 457.107 Florida...

  5. Transcriptome analysis of root response to citrus blight based on the newly assembled Swingle citrumelo draft genome

    OpenAIRE

    Zhang, Yunzeng; Barthe, Gary; Grosser, Jude W.; Wang, Nian

    2016-01-01

    Background Citrus blight is a citrus tree overall decline disease and causes serious losses in the citrus industry worldwide. Although it was described more than one hundred years ago, its causal agent remains unknown and its pathophysiology is not well determined, which hampers our understanding of the disease and design of suitable disease management. Results In this study, we sequenced and assembled the draft genome for Swingle citrumelo, one important citrus rootstock. The draft genome is...

  6. PHARMACOLOGICAL IMPORTANCE OF CITRUS FRUITS

    OpenAIRE

    Amita Tomar *, Mridula Mall and Pragya Rai

    2013-01-01

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

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

    Science.gov (United States)

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

    2015-12-02

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

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

    Directory of Open Access Journals (Sweden)

    Smita Raithore

    2015-12-01

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

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

    Science.gov (United States)

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

  10. Citrus Waste Biomass Program

    Energy Technology Data Exchange (ETDEWEB)

    Karel Grohman; Scott Stevenson

    2007-01-30

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

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

    Science.gov (United States)

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

    2014-10-01

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

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

    Science.gov (United States)

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

    2014-10-01

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

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

    Science.gov (United States)

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

    2016-07-17

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

  14. Chemical compounds effective against the citrus Huanglongbing bacterium 'Candidatus Liberibacter asiaticus' in planta.

    Science.gov (United States)

    Zhang, Muqing; Powell, Charles A; Zhou, Lijuan; He, Zhenli; Stover, Ed; Duan, Yongping

    2011-09-01

    Citrus Huanglongbing (HLB) is one of the most destructive diseases of citrus worldwide and is threatening the survival of the Floridian citrus industry. Currently, there is no established cure for this century-old and emerging disease. As a possible control strategy for citrus HLB, therapeutic compounds were screened using a propagation test system with 'Candidatus Liberibacter asiaticus'-infected periwinkle and citrus plants. The results demonstrated that the combination of penicillin and streptomycin (PS) was effective in eliminating or suppressing the 'Ca. L. asiaticus' bacterium and provided a therapeutically effective level of control for a much longer period of time than when administering either antibiotic separately. When treated with the PS, 'Ca. L. asiaticus'-infected periwinkle cuttings achieved 70% of regeneration rates versus citrus plants. This may provide a useful tool for the management of citrus HLB and other Liberibacter-associated diseases.

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

    OpenAIRE

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

    2016-01-01

    Pathogen-associated molecular patterns (PAMPs)-triggered immunity (PTI) is an important component of plant innate immunity. In a previous study, we showed that the PAMP flg22 from Xanthomonas citri ssp. citri (Xflg22), the causal agent of citrus canker, induced PTI in citrus, which correlated with the observed levels of canker resistance. Here, we identified and sequenced two bacterial flagellin/flg22 receptors (FLS2-1 and FLS2-2) from ‘Duncan’ grapefruit (Citrus paradisi, CpFLS2-1 and CpFLS2...

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

    Science.gov (United States)

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

    2010-08-01

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

  17. 晚熟温州蜜柑 NBS-LRR类抗病基因同源序列的克隆及分析%Cloning and Analysis of NBS-LRR Disease-Resistant Gene Analogs in Citrus unshiu Marc.

    Institute of Scientific and Technical Information of China (English)

    刘登全; 王园秀; 崔朝宇; 秦双林; 欧阳慧; 蒋军喜

    2016-01-01

    为加深对柑橘黄龙病抗性机理的了解和为黄龙病抗性基因的克隆提供依据,根据已知植物抗病基因NBS-LRR保守结构域设计简并引物,以柑橘黄龙病抗性品种“晚熟温州蜜柑”为供试材料,对其基因组DNA进行PCR扩增、克隆和序列测定,结果共获得17条抗病基因同源序列(resistance gene analogs,RGAs),其在NCBI中的登录号为KJ019189~KJ019199,KR815564~KR815569。序列分析表明,这17个RGAs与甜橙、柚等柑橘属中推测的一些抗病蛋白基因或其他相关蛋白基因具有显著高的同源性。其中一些RGAs与拟南芥抗霜霉病RPP13基因、柑橘抗衰退病毒基因Ctv或烟草抗TMV基因N具有51.7%~79.0%的氨基酸序列同源性。依据论文结果,笔者认为,晚熟温州蜜柑中存在较丰富的NBS-LRR类抗病基因,但具体哪些病基因与抗黄龙病相关尚需进一步研究。%In order to deepen understanding of the resistant mechanism of Citrus to Candiadatus Liberi-bacter asiaticus( CLas) and lay the foundation for cloning of citrus huanglongbing( HLB)-resistant gene,a pair of degenerate primers was designed from the conserved domains of NBS-LRR type plant disease-resistant gene and used for amplifying the disease-resistant gene analogs( RGAs) by polymerase chain reaction( PCR) from the genomic DNA of Citrus unshiu Marc.,a citrus cultivar resistant to HLB.After cloning and sequencing the PCR products,the nucleotide sequences and their deduced amino acid sequences of 17 RGAs were obtained and deposited in GenBank with the accession number of KJ019189-KJ019199 and KR815564-KR815569.Se-quence analysis showed that these 17 RGAs shared significantly high homology with some putative disease-re-sistant genes and other protein genes in Citrus sinensis or Citrus clementina, some of which shared 51.7%-79.0%amino acid sequence homology with the known disease gene of RPP13,Ctv,or N.Based on these re-sults,it is concluded

  18. Cloning and Analysis of NBS-LRR Disease-Resistant Gene Analogs in Citrus unshiu Marc.%晚熟温州蜜柑 NBS-LRR类抗病基因同源序列的克隆及分析

    Institute of Scientific and Technical Information of China (English)

    刘登全; 王园秀; 崔朝宇; 秦双林; 欧阳慧; 蒋军喜

    2016-01-01

    为加深对柑橘黄龙病抗性机理的了解和为黄龙病抗性基因的克隆提供依据,根据已知植物抗病基因NBS-LRR保守结构域设计简并引物,以柑橘黄龙病抗性品种“晚熟温州蜜柑”为供试材料,对其基因组DNA进行PCR扩增、克隆和序列测定,结果共获得17条抗病基因同源序列(resistance gene analogs,RGAs),其在NCBI中的登录号为KJ019189~KJ019199,KR815564~KR815569。序列分析表明,这17个RGAs与甜橙、柚等柑橘属中推测的一些抗病蛋白基因或其他相关蛋白基因具有显著高的同源性。其中一些RGAs与拟南芥抗霜霉病RPP13基因、柑橘抗衰退病毒基因Ctv或烟草抗TMV基因N具有51.7%~79.0%的氨基酸序列同源性。依据论文结果,笔者认为,晚熟温州蜜柑中存在较丰富的NBS-LRR类抗病基因,但具体哪些病基因与抗黄龙病相关尚需进一步研究。%In order to deepen understanding of the resistant mechanism of Citrus to Candiadatus Liberi-bacter asiaticus( CLas) and lay the foundation for cloning of citrus huanglongbing( HLB)-resistant gene,a pair of degenerate primers was designed from the conserved domains of NBS-LRR type plant disease-resistant gene and used for amplifying the disease-resistant gene analogs( RGAs) by polymerase chain reaction( PCR) from the genomic DNA of Citrus unshiu Marc.,a citrus cultivar resistant to HLB.After cloning and sequencing the PCR products,the nucleotide sequences and their deduced amino acid sequences of 17 RGAs were obtained and deposited in GenBank with the accession number of KJ019189-KJ019199 and KR815564-KR815569.Se-quence analysis showed that these 17 RGAs shared significantly high homology with some putative disease-re-sistant genes and other protein genes in Citrus sinensis or Citrus clementina, some of which shared 51.7%-79.0%amino acid sequence homology with the known disease gene of RPP13,Ctv,or N.Based on these re-sults,it is concluded

  19. Comparative analysis of surface wax in mature fruits between Satsuma mandarin (Citrus unshiu) and 'Newhall' navel orange (Citrus sinensis) from the perspective of crystal morphology, chemical composition and key gene expression.

    Science.gov (United States)

    Wang, Jinqiu; Hao, Haohao; Liu, Runsheng; Ma, Qiaoli; Xu, Juan; Chen, Feng; Cheng, Yunjiang; Deng, Xiuxin

    2014-06-15

    Surface wax of mature Satsuma mandarin (Citrus unshiu) and 'Newhall' navel orange (Citrus sinensis) was analysed by crystal morphology, chemical composition, and gene expression levels. The epicuticular and total waxes of both citrus cultivars were mostly composed of aldehydes, alkanes, fatty acids and primary alcohols. The epicuticular wax accounted for 80% of the total wax in the Newhall fruits and was higher than that in the Satsuma fruits. Scanning electron microscopy showed that larger and more wax platelets were deposited on the surface of Newhall fruits than on the Satsuma fruits. Moreover, the expression levels of genes involved in the wax formation were consistent with the biochemical and crystal morphological analyses. These diversities of fruit wax between the two cultivars may contribute to the differences of fruit postharvest storage properties, which can provide important information for the production of synthetic wax for citrus fruits.

  20. Postharvest Biocontrol: Introspection and Paradigm Shifts

    Science.gov (United States)

    The use of postharvest biocontrol agents as an alternative to the synthetic, chemical fungicides on a widespread basis has many constraints. During the last twenty years, the field of postharvest biocontrol research has significantly grown and developed and seen the creation of several products. Des...

  1. Post-harvest Proteomics and Food Security

    NARCIS (Netherlands)

    Pedreschi Plasencia, R.P.; Lurie, S.; Hertog, W.; Nicolai, B.; Mes, J.J.; Woltering, E.J.

    2013-01-01

    To guarantee sufficient food supply for a growing world population, efforts towards improving crop yield and plant resistance should be complemented with efforts to reduce postharvest losses. Post-harvest losses are substantial and occur at different stages of the food chain in developed and develop

  2. Métodos para identificação e controle da tristeza dos citros Methods of identification and control of tristeza disease of citrus

    Directory of Open Access Journals (Sweden)

    S. Moreira

    1954-01-01

    s vezes é possível o emprego de pés francos provenientes dos embriões nucelares. Nas plantações já existentes pode-se fazer a substituição total ou parcelada (individual das plantas, conforme se constate predominância de afídios muito ou pouco eficientes e de estirpes fortes ou fracas do vírus. A sub-enxertia ("inarching", a sôbre-enxertia ("topworking" e o afrancamento do enxerto são outras tantas modalidades de controle da tristeza, as quais podem ser vantajosamente empregadas em determinadas condições. Medidas de quarentena podem retardar a invasão das zonas ainda livres da tristeza, -sendo de interesse o esclarecimento do público quanto ao perigo representado pela importação de plantas ou suas partes vivas, exceto as sementes.The tristeza disease of citrus has not yet been reported from European countries nor from various other citrus growing areas of the world. Investigations on the disease have been carried out in various countries, such as Argentina, Australia, Brazil, South Africa, and United States. Knowledge obtained from these investigations enables citrus experts from areas not invaded by tristeza to recognize its presence in the orchards and to prevent disastrous losses for the industry. General decline symptoms of tristeza resemble those caused by foot rot, but root examination permits the differentiation of the two diseases. Presence of pitting symptoms in trees of West Indian limes or of grapefruits permits easy diagnosis of tristeza in the orchards. Stock-scion combinations may be tolerant or intolerant to tristeza. Thus, it be comes important to determine the rootstock in case of plants showing decline symptoms. This fact can be established by direct examination of sprouts from the rootstock or by observing the degree of congeniality of rootstock and scion. The colorimetric tests made with bark of the rootstock may help to determine it. Field observation of symptoms complemented by Schneider's histological tests may replace the

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

    Directory of Open Access Journals (Sweden)

    Abdelmonim Ali Ahmad

    2014-07-01

    Full Text Available In this study, filamentous phage XacF1, which can infect Xanthomonas axonopodis pv. citri (Xac strains, was isolated and characterized. Electron microscopy showed that XacF1 is a member of the family Inoviridae and is about 1000 nm long and 16 nm in width. The genome of XacF1 is 7325 nucleotides in size, containing 13 predicted open reading frames (ORFs, some of which showed significant homology to Ff-like phage proteins such as ORF1 (pII, ORF2 (pV, ORF6 (pIII, and ORF8 (pVI. XacF1 showed a relatively wide host range, infecting seven out of 11 strains tested in this study. Frequently, XacF1 was found to be integrated into the genome of Xac strains. This integration occurred at the host dif site (attB and was mediated by the host XerC/D recombination system. The attP sequence was identical to that of Xanthomonas phage Cf1c. Interestingly, infection by XacF1 phage caused several physiological changes to the bacterial host cells, including lower levels of extracellular polysaccharide production, reduced motility, slower growth rate, and a dramatic reduction in virulence. In particular, the reduction in virulence suggested possible utilization of XacF1 as a biological control agent against citrus canker disease.

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

    Institute of Scientific and Technical Information of China (English)

    金玲莉; 匡全; 王彦波

    2012-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  6. Utilization of an apple microarray for gene expression profiling in stone fruit-postharvest pathogen interactions

    Science.gov (United States)

    Brown rot disease (Monilinia fructicola Honey) is a major cause of Prunus spp. fruit losses in pre- and post-harvest settings. As part of an on-going effort to develop biological approaches for managing diseases of temperate fruit crops, we are seeking to better understand the mechanisms by which M...

  7. Citrus phytophtorose in humid subtropical zone of West Georgia

    Directory of Open Access Journals (Sweden)

    Mziuri Gabaidze

    2015-05-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2011-12-01

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

  10. Post-harvest proteomics and food security.

    Science.gov (United States)

    Pedreschi, Romina; Lurie, Susan; Hertog, Maarten; Nicolaï, Bart; Mes, Jurriaan; Woltering, Ernst

    2013-06-01

    To guarantee sufficient food supply for a growing world population, efforts towards improving crop yield and plant resistance should be complemented with efforts to reduce post-harvest losses. Post-harvest losses are substantial and occur at different stages of the food chain in developed and developing countries. In recent years, a substantially increasing interest can be seen in the application of proteomics to understand post-harvest events. In the near future post-harvest proteomics will be poised to move from fundamental research to aiding the reduction of food losses. Proteomics research can help in reducing food losses through (i) identification and validation of gene products associated to specific quality traits supporting marker-assisted crop improvement programmes, (ii) delivering markers of initial quality that allow optimisation of distribution conditions and prediction of remaining shelf-life for decision support systems and (iii) delivering early detection tools of physiological or pathogen-related post-harvest problems. In this manuscript, recent proteomics studies on post-harvest and stress physiology are reviewed and discussed. Perspectives on future directions of post-harvest proteomics studies aiming to reduce food losses are presented.

  11. Controle de doenças foliares e de flores e qualidade pós-colheita do morangueiro tratado com Saccharomyces cerevisiae Control of leaf and flower diseases and postharvest quality of strawberry plants treated with Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Alfredo de Gouvea

    2009-12-01

    Full Text Available O efeito de diferentes preparações de Saccharomyces cerevisiae foi avaliado sobre o desenvolvimento das doenças do morangueiro, como mancha-de-micosferela (Mycosphaerella fragariae, mancha-de-dendrofoma (Dendrophoma obscurans e flor-preta (Colletotrichum acutatum além da qualidade pós-colheita dos frutos. O trabalho foi realizado entre 2004 e 2005 na Universidade Tecnológica Federal do Paraná, Campus Dois Vizinhos. Os tratamentos consistiram de pulverizações semanais de cinco diferentes preparados a partir da levedura S. cerevisiae: suspensão com fermento biológico fresco comercial, suspensão de células de levedura, suspensão autoclavada de células, filtrado de cultura em meio líquido e Agro-MOS®, produto comercial formulado a partir da levedura, além da testemunha com água destilada e do tratamento controle com fungicidas. Nenhuma das preparações apresentou efeito contra a mancha-de-micosferela; preparações com a presença de células vivas e o produto Agro-MOS® apresentaram efeito contra mancha-de-dendrofoma; preparações com suspensão do produto comercial e filtrado de cultura líquida reduziram a incidência de flor-preta em flores e frutos. Preparações de S. cerevisiae com suspensão de células, suspensão autoclavada de células e filtrado de cultura líquida promoveram aumento na produtividade dos morangueiros que variou de 589,6 a 617,8 g planta-1. Preparações de S. cerevisiae, com presença de células vivas ou não, alteraram o metabolismo do morangueiro, aumentando a atividade das enzimas quitinase e glucanase, envolvidas na resistência sistêmica adquirida. Todos os tratamentos, com exceção do tratamento com suspensão autoclavada de células, reduziram a incidência de mofo-cinzento em pós-colheita de frutos.The effect of Saccharomyces cerevisiae was evaluated on the development of strawberry diseases and postharvest quality of fruits. The research was carried out in 2004 and 2005 in Paraná State

  12. Fuel from citrus waste

    Energy Technology Data Exchange (ETDEWEB)

    1979-08-01

    University of Florida researchers are looking for methods of using citrus peel to produce fuel for the citrus industry by using the methane gas given off in a special continuous digestion vessel. They are trying to discover ways to reduce the peel oil content of oranges as this oil inhibits the growth of organisms which produce the methane. The citrus industry currently utilizes orange peel and pulp to make cattle feed, but since the peel has to be dried this step consumes a lot of energy.

  13. Investigation of heat treating conditions for enhancing the anti-inflammatory activity of citrus fruit (Citrus reticulata) peels.

    Science.gov (United States)

    Ho, Su-Chen; Lin, Chih-Cheng

    2008-09-10

    In traditional Chinese medicine, dried citrus fruit peels are widely used as remedies to alleviate coughs and reduce phlegm in the respiratory tract. Induction of inducible nitric oxide synthase (iNOS) in inflammatory cells and increased airway production of nitric oxide (NO) are well recognized as key events in inflammation-related respiratory tract diseases. Despite the fact that the enhancing effect of heat treatment on the antioxidant activity of citrus fruit peels has been well documented, the impact of heat treatment on citrus peel beneficial activities regarding anti-inflammation is unclear. To address this issue, we determined the anti-inflammatory activities of heat-treated citrus peel extracts by measuring their inhibitory effect upon NO production by lipopolysaccharide-activated RAW 264.7 macrophages. Results showed that the anti-inflammatory activity of citrus peel was significantly elevated after 100 degrees C heat treatment in a time-dependent fashion during a period from 0 to 120 min. Inhibition of iNOS gene expression was the major NO-suppressing mechanism of the citrus peel extract. Additionally, the anti-inflammatory activity of citrus peel extract highly correlated with the content of nobiletin and tangeretin. Conclusively, proper and reasonable heat treatment helped to release nobiletin and tangeretin, which were responsible for the increased anti-inflammatory activity of heat-treated citrus peels. PMID:18683945

  14. Temporal Pattern Analysis of Citrus Diseases and Pests in Jiangxi Province based on Circular Statistics%圆形分布统计的江西省柑橘病虫害时间格局分析

    Institute of Scientific and Technical Information of China (English)

    张伟; 戴小华; 徐家生; 王飞

    2014-01-01

    Circular statistical methods were used to analyse the occurrence levels of major pests and diseases on Citrus crops be▬tween 2006 and 2008 in Jiangxi province,in order to clarify the temporal distribution patterns of citrus diseases and pests• The results show that the occurrence of different citrus diseases and pests had different monthly rhythms,which were also various in different areas•Circular statistics is useful for the study on circadian rhythms and seasonal rhythms of pests and their natural enemies• It will provide a theoretical basis for the integrated management of plant diseases and pests•%采用圆形分布统计方法,对2006年至2008年之间江西省部分地区的柑橘主要病害虫的发生等级进行数据分析,以研究江西省柑橘主要病虫害的时间分布格局•结果表明,不同柑橘病虫害的发生呈现出不同的月份节律,且各病虫害在不同地区发生程度不同•圆形分布统计可用于病虫害及其天敌的昼夜节律和季节节律研究,将为病虫害综合防治提供理论基础•

  15. Comparison of PCR,DIA and Pathogenicity Assay for Detection of Xanthomonas axonopodis pv.citri,the Causal Agent of Citrus Bacterial Canker Disease

    Institute of Scientific and Technical Information of China (English)

    WANG Zhong-kang; SUN Xian-yun; YIN You-ping; ZHOU Chang-yong; XIA Yu-xian

    2004-01-01

    Polymerase chain reaction (PCR) approach based on newly designed primers, JYF5/JYR5, was applied for specific detection of Xanthomonas axonopodis pv.citri(Xac). The efficiency and reliability of PCR method were compared with dot immunobinding assay (DIA) and classical pathogenicity test techniques for detecting suspensions of pure cells of Xac and soaking sap of citrus tissues. Detection sensitivity of PCR was about 4.5 cells or 1.56 pg target DNA per reaction which was higher than that of DIA (ca. 450 cells per dot).These three techniques (PCR assay, DIA and Pathogenecity test) could always detect Xac from symptomatic citrus samples. Different performances were obtained from citrus materials without symptoms, and the positive detection frequency was PCR, DIA and pathogenicity test.

  16. 本地早柑桔衰退病毒病的交叉保护研究%Study of cross protection of citrus tristeza viruse disease on Bendizao mandarin (Citrus succosa ).

    Institute of Scientific and Technical Information of China (English)

    崔伯法; 崔圣为; 王洪祥; 翁法令; 龚吉强

    2005-01-01

    1995~1996年从黄岩不同桔区的"本地早"(Citrus succosa)桔树采样,经指示植物墨西哥莱檬(Citrus auranti folia)鉴定,得到18个柑桔衰退病毒(Citrus tristeza virus,CTV)分离毒株.根据茎陷点数/cm2划分,其中有弱毒分离株7株,中毒株5株和强毒株6株.网室试验的结果显示,在墨西哥莱檬上预先接种弱毒或中毒分离株后再以强毒株挑战接种的处理,其茎陷点数/cm2比仅接种强毒株的处理显著减少,其生长量也明显大于仅接种强毒株的植株,显示了明显的交叉保护作用.田间试验是以枳壳或以枸头橙为砧木的本地早,分别以不同毒性的CTV毒株接种后移植田间.在移植后第5~7年进行调查.结果证明,以弱毒或中毒分离株接种的植株,和以弱毒株预接种后再接种强毒株的植株,其3年的年均小果率均显著低于单接强毒株的植株,也显著低于未接种的田间植株.说明CTV弱毒株或中毒株的预接种对CTV的强毒株再侵染和田间毒株的自然侵染有明显的保护作用.同时,选择带弱毒株、中毒株和强毒株的田间定点病树各3株,连续3年调查产量及树体生长量.结果显示,感染弱毒株或中毒株的病树,产量高于重病树,小果率低于重病树,说明CTV的交叉保护现象在自然界存在.

  17. Sustainable postharvest handling of horticultural products

    OpenAIRE

    Antunes, Maria Dulce; Miguel, Maria Graça; Neves, A.

    2007-01-01

    Sustainable commercial horticultural success depends on satisfying consumer requirements. Fresh fruits and vegetables are important components of human food. However, horticultural products are highly perishable and losses can be of great importance if postharvest correct measures are not provided. Quality of fresh horticultural products can not be improved by postharvest technologies, only can be maintained, what means horticultural products must be of high quality at harvest. There is a wor...

  18. The Asian Citrus Psyllid Genome (Diaphorina citri, Hemiptera)

    OpenAIRE

    Hunter, Wayne B.; Reese, Justin; International Psyllid Genome Consortium, The

    2014-01-01

    The Asian citrus psyllid, Diaphorina citri (Hemiptera), is an important pest of citrus because it vectors bacteria responsible for huanglongbing, which is one of the most serious diseases of citrus worldwide.  The first genome draft of D. citri (DIACI_1.0) was completed in 2011 (ARS, Ft. Pierce, FL), however, gaps in the assembly prompted additional sequencing using the long run PacBio system at the Los Alamos National Lab, NM.  The revised draft genome (DIACI_1.1) was assembled using the new...

  19. 拮抗酵母菌对果蔬采后病害生防增效途径及机理研究进展%Recent Advances in Research on Approaches and Mechanisms of Improving Biocontrol Efficacy of Antagonistical Yeasts against Postharvest Diseases of Fruits and Vegetables

    Institute of Scientific and Technical Information of China (English)

    周雅涵; 罗杨; 曾凯芳

    2011-01-01

    Based on the characteristics of antagonistical yeasts and the major reasons for the limitation in commercial application,the current approaches and mechanisms of improving biocontrol efficacy of antagonistical yeasts against postharvest diseases of fruits and vegetables are discussed.Prospective directions for research on technologies for improving the biocontrol efficacy of antagonistical yeasts are also put forward.This paper will provide some guidance for the commercialization of antagonistical yeasts and the application of biological technology in postharvest disease control of fruits and vegetables.%本文在总结拮抗酵母菌特点的基础上,针对限制其商业化应用的主要原因,重点阐述增强拮抗酵母菌对果蔬采后病害生防效力的途径及机理,最后进一步提出拮抗酵母菌增效技术未来的研究方向。以此,为拮抗酵母菌的商业化推广和应用及生物防治技术在控制采后果蔬病害中的应用提供指导。

  20. PHARMACOLOGICAL IMPORTANCE OF CITRUS FRUITS

    Directory of Open Access Journals (Sweden)

    Amita Tomar *, Mridula Mall and Pragya Rai

    2013-01-01

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

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

    Science.gov (United States)

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

    2015-12-01

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

  2. Selection and testing of epiphytic yeasts to control anthacnose in post-harvest of papaya fruit

    NARCIS (Netherlands)

    Capdeville, G.; Souza, M.T.; Santos, J.R.P.; Miranda, S.P.; Caetano, A.R.; Torres, F.A.G.

    2007-01-01

    Anthracnose, caused by Colletotrichum gloeosporioides, is a major post-harvest disease in papaya fruit. The major objectives of the present work were to isolate, select and test the in vitro and in vivo ability of epiphytic microorganisms, isolated from papaya fruit and leaf surfaces, in controlling

  3. Reasoned opinion on the setting of an import tolerance for didecyldimethylammonium chloride (DDAC in citrus

    Directory of Open Access Journals (Sweden)

    European Food Safety Authority

    2013-05-01

    Full Text Available In accordance with Article 6 of Regulation (EC No 396/2005, The Netherlands, hereafter referred to as the evaluating Member State (EMS, received an application from Exponent International Ltd (on behalf of ICA International Chemicals (PTY Ltd to set an import tolerance in citrus from South Africa for the active substance didecyldimethylammonium chloride (DDAC at the level of 6 mg/kg. The Netherlands drafted an evaluation report in accordance with Article 8 of Regulation (EC No 396/2005, which was submitted to the European Commission and forwarded to EFSA. According to EFSA, the data require the setting of an import tolerance of 6 mg/kg for citrus. However, additional information on the typical South African post-harvest treatment practice should be provided to decide whether the submitted trials are representative of the authorised GAP. A sufficiently validated analytical method to enforce the proposed MRL of DDAC on citrus is available. EFSA concludes that the consumer risk assessment did not identify a consumer health risk resulting from the post harvest uses of DDAC on citrus fruits. However it should be noted that the risk assessment is affected by a high degree of uncertainties which result from data gaps identified in the dossier. Finally, EFSA concludes that risk managers have to decide whether the setting of an import tolerance of 6 mg/kg is acceptable since the MRL currently into force for citrus in South Africa is 2 mg/kg only.

  4. Identification of Disease Resistance of Different Introduced Citrus Varieties to Anthracnose in Guizhou%贵州新引进柑橘品种对炭疽病的抗性鉴定

    Institute of Scientific and Technical Information of China (English)

    周小燕; 曾琛; 姜于兰

    2012-01-01

    The detached leaf disease resistance identification method was used to assess the resistance of 14 kinds of introduced citrus varieties to citrus anthracnose in Guizhou. The results showed that there were some differencees between the 14 kinds of citrus cultivars in disease resistance at 4 and 5 days after inoculation. The disease index of Amakusa was 0 and 0. 46,Fola was 52. 78 and 79. 17,Setoka was 1. 85 and 2. 78,Nova was 4. 63 and 9. 26,respectively,after 4 and 5 days. The results of two surveys revealed that the disease index of Amakusa was the minimum, and its disease resistance was the strongest, showing immunity or high resistance. The disease index of Fola was the maximum,and its disease resistance was the weakest,showing high susceptibility. Setoka and Nova were all highly resistant.%为明确贵州新引进的14个柑橘品种对炭疽病的抗病能力,采用离体叶片法测定了其对柑橘炭疽病的抗病性.结果表明,14个参试柑橘品种在接种4d和5d后,抗病性存在差异.其中,天草在接种4d和5d后的病情指数分别为0和0.46,佛拉的病情指数分别为52.78、79.17,濑户佳的病情指数分别为1.85、2.78,若瓦的病情指数分别为4.63、9.26.2次的调查结果都说明天草的病情指数最小,抗病性最强,表现为免疫或高抗;佛拉的病情指数最大,抗病性最弱,表现为感病;濑户佳、若瓦均表现高抗.

  5. 柑桔黄龙病的可见-近红外光谱特征%Visible-NIR Spectral Feature of Citrus Greening Disease

    Institute of Scientific and Technical Information of China (English)

    李修华; 李民赞; Won Suk Lee; Reza Ehsani; Ashish Ratn Mishra

    2014-01-01

    柑桔黄龙病是一种以木虱为载体的细菌病原,目前还没有行之有效的治疗方法,对世界柑桔产业构成了严重的威胁。探索快速检测柑桔黄龙病的方法,对该病的诊断、评估及进一步的控制都具有重要意义。该研究采用了快速、无损的光谱方法对该病害特征进行初步探索。实验针对健康及染病植株的叶片及冠层,分别在实验室条件及田间环境下测量了其可见-近红外光谱反射率,以分析寻找二者的光谱差异。对原始光谱数据进行了平滑、聚类平均等预处理,并求取了一阶微分以确定其红边位置(red edge position, REP)。为了应对一阶微分在REP处的多个波峰现象,采用了线性外插值法及拉格朗日插值法量化REP。研究结果显示,健康及染病样本的反射率在可见光、近红外具有明显的差异。相比于健康样本,染病样本因其呈现的黄化现象,使其反射率在可见光区较高;又因黄龙病菌会明显阻碍叶片对水分的吸收而使其反射率在近红外较低。REP同样显示了潜在的区分能力,其明显随着染病程度的加深逐渐向红波段移动。在染病程度差异较大的数据集中,REP平均值相差达20 nm;而在染病程度差异较小的数据集中,阈值分割法的分类精度也高达90%以上,且线性外插值法的分类精度略高于拉格朗日插值法。本研究成果为利用光谱技术快速无损检测柑桔黄龙病提供了可靠的理论依据。%Citrus greening (Huanglongbing,or HLB)is a devastating disease caused by Candidatus liberibacter which uses psyl-lids as vectors.It has no cure till now,and poses a huge threat to citrus industry around the world.In order to diagnose,assess and further control this disease,it is of great importance to first find a quick and effective way to detect it.Spectroscopy method, which was widely considered as a fast and nondestructive way

  6. Identification of the pathogens of postharvest apricot fruit diseases and indoor screening of fungicides%杏采后病害病原菌鉴定及室内药剂筛选

    Institute of Scientific and Technical Information of China (English)

    张瑾; 徐秉良; 梁巧兰; 张文利; 吴步梅

    2011-01-01

    [Objective] To identify the main pathogens causing fruit rot of storage apricots and screen the effective fungicides, so as to prolong the storage period of apricots and decrease the losses. [Method] Isolation and identification, as well as pathogenicity test and return inoculation experiments were made for the pathogen causing fruit rot of storage apricots in Lanzhou City, Gansu Province. The effective fungicides for the main pathogens were also screened in the laboratory. [Result] Six fungi were identified as the pathogens causing fruit rot of storage apricots, which were Trichothecium roseum Lk. Ex Fr., Alternaria alternata (Fr.) Keissl., Rhizopus nigricans (Ehrenb), Penicillium frequentans, Botrytis cinerea and Monilinia laxa (Aderh. & Ruhl.) Honey. The main pathogens causing postharvest diseases of apricots were A. Alternata, R. Nigricans and T. Roseum. The isolation frequencies of them were 28. 5%, 48. 9% and 9. 4%, respectively. After artificial inoculation with or without wounds, the incidence of fruits infected by A. Alternata, R. Nigricans and T. Roseum were 100%, 100% and 83%, respectively. The results of chemical screening showed that, in PDA media plate, the fludioxonil (50%WP) and iprodione (50% SC) were most effective in controlling the three main pathogens, and the average effect reached more than 94%. The test of fungicides antisepsis of fruits showed that apricots were dipped in the 9000× diluted solution of fludioxonil (50%WP) or in the 1000 X diluted solution of iprodione (50%SC) for 3 min and stored at room temperature (25℃) for 7 days and 13 days. The control effects of fludioxonil against T. Roseum, A. Alternata and R. Nigricans were 78.3%/65%, 79% /67.5% and 80.3%/69.6%, respectively, and the con-trol effects of iprodione were 76%/64.3%, 78. 3%/64.4% and 78.6%/66.4%, respectively. [Conclusion] Theresults may provide a reference for the control of postharvest diseases of apricots.%[目的]确定引起杏采后病害的主要病原菌及

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

    Science.gov (United States)

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

  8. Postharvest diseases and physicochemical characteristics of mango / Doenças e características físicas e químicas pós-colheita em manga

    Directory of Open Access Journals (Sweden)

    Eliane Maria Ravasi Stefano Simionato

    2009-07-01

    Full Text Available The objective of this work was to identify and to quantify the postharvest diseases and to evaluate the physical and chemical characteristics of mango fruits cvs. Haden, Tommy Atkins, Palmer and Keitt, submitted or not to the treatment with the fungicide carbendazim. The fruits had been harvested in a commercial orchard in President Prudente-SP, individualized and kept in a humid chamber for 24h, remaining eight days at 25±2ºC and 70-80% RH. The incidence of diseases, the firmness and the loss of mass were evaluated periodically, during nine days. Before and to the end of the storage, the fruits had been characterized to titratable acidity and soluble solids content. There was high occurrence of rots in the four mango cultivars. Anthracnose was the most frequent disease, with practically 100% of incidence in the fruits. The Lasiodiplodia stem-end rot had greater incidence in cv. Tommy Atkins (68%, followed for the Haden (36%. The treatment with carbendazim presented changeable efficiency in the control of the rots, in function of mango cultivar. This treatment is recommended for the control of the stem-end in cvs. Haden and Palmer and also to reduce the severity of anthracnose in cvs. Haden and Keitt. The fungicide application did not influence soluble solids and titratable acidity content and ratio of mango cultivars, except in Palmer that presented minor ratio when treated with fungicide. The ethefon application did not influence the ripening process of mango cv. Haden.O presente trabalho objetivou identificar e quantificar as doenças pós-colheita e avaliar as características físicas e químicas de frutos de manga cultivares Haden, Tommy Atkins, Palmer e Keitt submetidos, ou não, ao tratamento com o fungicida carbendazim. Os frutos foram colhidos em um pomar comercial em Presidente Prudente-SP, individualizados e submetidos a 24h de câmara úmida, permanecendo por mais oito dias a 25±2ºC e 70-80% de UR. A incidência de doenças, a

  9. Citrus Improvement Using Mutation Techniques

    International Nuclear Information System (INIS)

    Pineapple orange, and the University of Florida a seedless Murcot tangor. Mutation has been also important in lemon breeding, and a seedless lemon, with tolerance to a devastating lemon disease was recently reported, in addition to earlier reports of a thornless lemon mutant produced by gamma irradiation. Gamma irradiation is currently an important component of our breeding programme and several potentially improved cultivars of grapefruit, pummelos, and lemons are in the pipeline. Additional details of citrus irradiation programmes in the US will be provided. (author)

  10. Commercial risk-based survey for HLB and implications for efficacy of Citrus Health Management Areas (CHMAs)

    OpenAIRE

    Gottwald, T.; Luo, W.; Riley, T; Parnell, S.

    2014-01-01

    The USDA, APHIS, PPQ has been conducting a risk-based multi-pest survey (MPS) for the past two years.  The initial 6 statewide survey cycles were conducted on a 6 week basis, whereas the subsequent 20 cycles have been conducted on a 3-week basis.  HLB and ACP are the two main pests addressed by the MPS but other citrus pests and diseases, i.e., Asiatic Citrus Canker (ACC), Citrus Leprosis Virus (CLiV), Citrus Black Spot (CBS) and Citrus Variegated Chlorosis (CVC) were also given lesser emphas...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-22

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

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

    Directory of Open Access Journals (Sweden)

    Min-A Song

    2015-12-01

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

  13. The ability of the antagonist yeast Pichia guilliermondii strain Z1 to suppress green mould infection in citrus fruit

    Directory of Open Access Journals (Sweden)

    Rachid Lahlali

    2014-12-01

    Full Text Available In previous studies it was shown that Pichia guilliermondii strain Z1, isolated from healthy Moroccan citrus Valencia-Late oranges, was effective against Penicillium italicum. Here the effectiveness of strain Z1 was assessed against Penicillium digitatum, the causal agent of green mould, under different temperature (5-25°C and relative humidity (RH (45-100% regimes for its reliable and largescale application in packinghouse. All main effects and interactions were significant (P80%. Its applications as a formulated product significantly reduced the incidence of infected fruit (55% and the percentage of infected wounds (47% compared to the only pathogen control treatment. However, disease control with formulated product was significantly less than that obtained with thiabendazole (30% or strain Z1 culturable cells (35%. These results highlight that strain Z1 is an effective biological control agent for control of green mould under varying environmental conditions, and control may be optimized by combining its use with other environmentally-safe post-harvest treatments or improved formulation.

  14. Pre- and postharvest fungal apple diseases

    Science.gov (United States)

    The domesticated apple (Malus domestica) is the most significant pome fruit grown and consumed worldwide. China is the largest producer followed by the United States on a global scale. However, fungal plant pathogens cause significant economic losses in the field and in storage which negatively impa...

  15. Effects of Ionizing Radiation on Postharvest Fungal Pathogens.

    Science.gov (United States)

    Jeong, Rae-Dong; Shin, Eun-Jung; Chu, Eun-Hee; Park, Hae-Jun

    2015-06-01

    Postharvest diseases cause losses in a wide variety of crops around the world. Irradiation, a useful nonchemical approach, has been used as an alternative treatment for fungicide to control plant fungal pathogens. For a preliminary study, ionizing radiations (gamma, X-ray, or e-beam irradiation) were evaluated for their antifungal activity against Botrytis cinerea, Penicillium expansum, and Rhizopus stolonifer through mycelial growth, spore germination, and morphological analysis under various conditions. Different fungi exhibited different radiosensitivity. The inhibition of fungal growth showed in a dose-dependent manner. Three fungal pathogens have greater sensitivity to the e-beam treatment compared to gamma or X-ray irradiations. The inactivation of individual fungal-viability to different irradiations can be considered between 3-4 kGy for B. cinerea and 1-2 kGy for P. expansum and R. stolonifer based on the radiosensitive and radio-resistant species, respectively. These preliminary data will provide critical information to control postharvest diseases through radiation. PMID:26060436

  16. Citrus tristeza virus-host interactions

    Directory of Open Access Journals (Sweden)

    William O. Dawson

    2013-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Chuanyu Yang

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

  2. Potential Nutritional Benefits of Current Citrus Consumption

    OpenAIRE

    Tami Turner; Burri, Betty J.

    2013-01-01

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

  3. Potential Nutritional Benefits of Current Citrus Consumption

    Directory of Open Access Journals (Sweden)

    Tami Turner

    2013-03-01

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

  4. Disinfection of Citrus Storage Room by Fumigation with Two Plants and Chemical Product Deccofenato Pot against the Viability of Penicillium Spp Spores

    OpenAIRE

    M. C. Elbouchtaoui; L. M. Idrissi Hassani

    2014-01-01

    Citrus fruits are subject to many postharvest phytopathogenic fungi that cause severe economic losses. The most attacks are mainly due the genus Penicillium spp. The treatment of these fungi uses a lot of chemicals that negatively affect environment and human health. Our study aims to test the antifungal activity by fumigation of two plants and a new chemical pesticide at the station Agrumar Souss, Ait Melloul. Plants and pesticide Deccofenato pot were used as fumigation in or...

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

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

  9. Use of nootkatone as a senescence indicator for Rouge La Toma Cv. grapefruit (Citrus paradisi Macf.).

    Science.gov (United States)

    Biolatto, Andrea; Sancho, Ana M; Cantet, Rodolfo J C; Güemes, Daniel R; Pensel, Norma A

    2002-08-14

    The objective of this research was to study the usefulness of nootkatone as a senescence indicator for Rouge La Toma cv. grapefruit (Citrus paradisi Macf.), simulating different treatments that included the normal postharvest handling of citrus fruits: temperature conditioning, cold storage, shipment periods to overseas markets such as Japan and the U.S., marketing conditions, and storage at nonchilling temperature (control treatments). The highest nootkatone levels, determined by GLC-MS analyses, were detected in fruits subjected to control treatments. No significant differences were observed in nootkatone levels between treatments either with or without temperature conditioning prior to the start of the cold storage. Levels of nootkatone increased throughout time for all assayed treatments. The linear regressions of nootkatone levels showed correlation coefficients of 0.80 and 0.83 with storage time (29 and 42 days, respectively). Therefore, nootkatone appears to be a good indicator of senescence for Rouge La Toma grapefruit. PMID:12166965

  10. Postharvest of ‘Fuerte’ and ‘Hass’ avocados: physical and chemical characteristics, damages and control of diseases/ Pós-colheita de abacates ‘Fuerte’ e ‘Hass’: características físicas e químicas, danos e controle de doenças

    Directory of Open Access Journals (Sweden)

    Maria Cecília Arruda

    Full Text Available Postharvest disease is considered an important cause of avocado depreciation during its commercialization. This work aimed to evaluate the postharvest damages and the physical chemical characteristics of avocados ‘Fuerte’ and ‘Hass’, processed at the packinghouse, and to evaluate the effect of products for postharvest disease control. The characteristics skin color, firmness, titratable acidity and soluble solids content and the incidence of the postharvest damages were evaluated periodically in avocados sampled in three different stages in a packinghouse (arrival, pallet and processed fruits after storage for 30 days at 5ºC. For diseases control, ‘Hass’ avocado were treated by immersion with the following products: azoxystrobin, benzalkonium chloride, chlorine dioxide, Ecolife®, sodium hypochlorite, imazalil, prochloraz and thiabendazole. In general, the highest physical chemical changes were observed in fruits collected at their arrival to the packinghouse and in processed fruits after stored for 30 days at 15 days of storage at 25°C. The rots incidence was 56,7% in ‘Fuerte’ and 75,7% in ‘Hass’. Lower incidence of rots was observed in fruits sampled at the pallet and a higher incidence in the processed fruits, after refrigerated storage. Anthracnose was the most important disease in both cultivars. The mechanical injuries increased with the processing stages; however, they did not influence the incidence of the rots. Procloraz and imazalil were the most efficient fungicides in reducing the incidence of rots. Doença pós-colheita é considerada uma importante causa de desvalorização do abacate por ocasião da comercialização. Este trabalho objetivou avaliar os danos pós-colheita e as características físicas e químicas de abacates ‘Fuerte’ e ‘Hass’, beneficiados em packinghouse, e o efeito de produtos no controle pós-colheita das podridões. As características cor da casca, firmeza, acidez titulável e s

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

    Yan, Huaxue; Zeng, Jiwu; Zhong, Guangyan

    2015-07-01

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

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

    Science.gov (United States)

    Yan, Huaxue; Zeng, Jiwu; Zhong, Guangyan

    2015-07-01

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

  14. Commercialization of postharvest biocontrol: barriers and opportunities

    Science.gov (United States)

    The past twenty years has seen the field of postharvest biocontrol evolve from an unknown entity with one or two novel reports in the literature to a sophisticated science with strong research programs worldwide, hundreds of publications, patented technologies, and now several commercial products. ...

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

    Directory of Open Access Journals (Sweden)

    Neelam Mallick

    2016-01-01

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

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

    OpenAIRE

    Rauf, Abdur; Uddin, Ghias; Ali, Jawad

    2014-01-01

    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 pl...

  17. Huanglongbing:An overview of a complex pathosystem ravaging the world’s citrus

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

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

  18. Valuing Catastrophic Citrus Losses

    OpenAIRE

    Adams, Damian C.; Kilmer, Richard L.; Moss, Charles B.; Schmitz, Andrew

    2004-01-01

    Courts are often required to estimate changes in welfare to agricultural operations from catastrophic events. For example, courts must assign damages in lawsuits, such as with pesticide drift cases, or determine "just compensation" when the government takes private land for public use, as with the removal of dairy farms from environmentally sensitive land or destruction of canker-contaminated citrus trees. In economics, the traditional method of quantifying producer losses is estimating chang...

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

    Science.gov (United States)

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

    2014-12-01

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

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

    Science.gov (United States)

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

    2014-12-01

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

  1. Review of the Status of Irradiation Effects on Citrus Fruits

    International Nuclear Information System (INIS)

    The United States fresh-market spoilage losses valued at the 1959-1963 retail prices were estimated for oranges and grapefruit to be $8.4 and $5.4 million, respectively. Stem-end rots and green and blue molds cause the greatest post-harvest decay losses to citrus. No single radiation dose can be given that will be the minimum required for protecting citrus fruits against spoilage. Radiation doses required for retarding old or established infections are higher than for the retardation of incipient infections. The flux, as well as the dose of gamma radiation influences the control of infections. Fresh citrus fruits undergo metabolic changes which ultimately lead to senescence. Some of these changes include varied activities in the levels of respiration, organic acids, sugars, pectic substances and color. In many respects the loss of cellular vitality in senescence resembles the effects of radiation injury. Irradiation causes changes in the pectic components of fruits. In general, an increase occurs in the water and ammonium oxalate-soluble fractions and a decrease occurs in the sodium hydroxide-soluble fraction. A large increase of water-soluble pectin is found in the juice extracted from irradiated fruits. Apparently this increases results from movement of the water-soluble pectin from other parts of the fruit. A marked increase in the viscosity of the juice results. Peel injury is sometimes found following irradiation and storage of the fruit. The per centage of fruit showing peel injury, and the severity of the injury, increase the higher the storage temperature and the longer the storage duration. Oranges and grapefruit may be irradiated with doses of up to 200 krad without any appreciable deleterious effects on organoleptic qualities. (author)

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

    OpenAIRE

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

    2015-01-01

    Citrus fruits, which are cultivated worldwide, have been recognized as some of the most high-consumption fruits in terms of energy, nutrients and health supplements. What is more, a number of these fruits have been used as traditional medicinal herbs to cure diseases in several Asian countries. Numerous studies have focused on Citrus secondary metabolites as well as bioactivities and have been intended to develop new chemotherapeutic or complementary medicine in recent decades. Citrus-derived...

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

    Institute of Scientific and Technical Information of China (English)

    李燕辉; 彭昌家; 苟建华; 李鸿韬

    2014-01-01

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

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

    Science.gov (United States)

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

    2015-05-01

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

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

    Science.gov (United States)

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

    2015-05-01

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

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

    KAUST Repository

    Piazza, A.

    2015-03-14

    Xanthomonas citri subsp. citri (Xcc) is a bacterial pathogen that causes citrus canker in susceptible Citrus spp. The Xcc genome contains genes encoding enzymes from three separate pathways of trehalose biosynthesis. Expression of genes encoding trehalose-6-phosphate synthase (otsA) and trehalose phosphatase (otsB) was highly induced during canker development, suggesting that the two-step pathway of trehalose biosynthesis via trehalose-6-phosphate has a function in pathogenesis. This pathway was eliminated from the bacterium by deletion of the otsA gene. The resulting XccΔotsA mutant produced less trehalose than the wild-type strain, was less resistant to salt and oxidative stresses, and was less able to colonize plant tissues. Gene expression and proteomic analyses of infected leaves showed that infection with XccΔotsA triggered only weak defence responses in the plant compared with infection with Xcc, and had less impact on the host plant\\'s metabolism than the wild-type strain. These results suggested that trehalose of bacterial origin, synthesized via the otsA-otsB pathway, in Xcc, plays a role in modifying the host plant\\'s metabolism to its own advantage but is also perceived by the plant as a sign of pathogen attack. Thus, trehalose biosynthesis has both positive and negative consequences for Xcc. On the one hand, it enables this bacterial pathogen to survive in the inhospitable environment of the leaf surface before infection and exploit the host plant\\'s resources after infection, but on the other hand, it is a tell-tale sign of the pathogen\\'s presence that triggers the plant to defend itself against infection. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  7. Thermal control of some post-harvest rot pathogens of Irish potato (solanum tuberosum l.)

    OpenAIRE

    Salami Olusola Abiodun; Popoola Omololu Olumide

    2007-01-01

    Thermal control effect on the incidence of some post-harvest rot pathogens of Solanum tuberosum (potato) was investigated in this study. Three cultivars of potato tuber whose local names are, Patiska, Mai Bawondoya and Nicola were used for the study. Five pathogenic fungi viz: Botryodiplodia theobromae, Fusarium redolens, Fusarium oxysporum, Penicillium sp. and Rhizopus oryzae associated with post harvest storage rot of root-tubers, were isolated from diseased potatoes. Among the three specie...

  8. PROPOLIS EXTRACT IN POSTHARVEST CONSERVATION BANANA ' PRATA'

    OpenAIRE

    FLÁVIA REGINA PASSOS; FABRÍCIA QUEIROZ MENDES; MARIANA CRIVELARI DA CUNHA; MARIANA TEIXEIRA PIGOZZI; ANDRÉ MUNDSTOCK XAVIER DE CARVALHO

    2016-01-01

    ABSTRACT In the present work were evaluated the effects of propolis coatings of various botanical sources on quality traits of bananas cv. Prata (Musa sapientum L.) stored at room temperature. ´Prata´ bananas were selected and submitted to five postharvest treatments: four coatings applied by immersion in propolis extracts at a concentration of 2.5% (w/v) and a control (without coating). Propolis extracts were applied as 1) a wild type aqueous propolis extract, 2) a wild type hydroalcoholic ...

  9. Roadmapping for improving cocoa postharvest management

    OpenAIRE

    Adriana del Pilar Sánchez Vargas; Óscar Fernando Castellanos Domínguez; Karen Patricia Domínguez Martínez

    2010-01-01

    This article presents the methodology and results which led to preparing post-harvesting technological development strategies for cocoa management which emerged from identifying problems such as deficient cocoa quality and insufficient fermentation of the beans according to international market requirements as shown in the poor technological development in Colombia’s main co-coa producing areas. This situation led to using a technological management tool such as roadmapping orientated towards...

  10. Citrus peel waste treatment

    Energy Technology Data Exchange (ETDEWEB)

    Yamanouchi, I.; Kuno, H.

    1977-07-30

    Citrus peel waste from canneries are treated with an acid and an additional base then fermented by anaerobic bacteria to produce CH/sub 4/. Then the solution is aerobically treated and discharged. The excess activated sludge is recycled for fermentation. Thus, a mixture of mandarin-orange cannery waste (80% water) and 0.5% HCl was heated at 120/sup 0/ to hydrolyze the organic matter to obtain a solution containing glucose and suspended solids. The solution is then enriched with N and P for fermentation to produce 50 L of CH/sub 4/ in 5 days vs 25 L without HCl.

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

    DEFF Research Database (Denmark)

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

    2011-01-01

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

  12. Sequencing and computational analysis of complete genome sequences of Citrus yellow mosaic badna virus from acid lime and pummelo.

    Science.gov (United States)

    Borah, Basanta K; Johnson, A M Anthony; Sai Gopal, D V R; Dasgupta, Indranil

    2009-08-01

    Citrus yellow mosaic badna virus (CMBV), a member of the Family Caulimoviridae, Genus Badnavirus, is the causative agent of Citrus mosaic disease in India. Although the virus has been detected in several citrus species, only two full-length genomes, one each from Sweet orange and Rangpur lime, are available in publicly accessible databases. In order to obtain a better understanding of the genetic variability of the virus in other citrus mosaic-affected citrus species, we performed the cloning and sequence analysis of complete genomes of CMBV from two additional citrus species, Acid lime and Pummelo. We show that CMBV genomes from the two hosts share high homology with previously reported CMBV sequences and hence conclude that the new isolates represent variants of the virus present in these species. Based on in silico sequence analysis, we predict the possible function of the protein encoded by one of the five ORFs.

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

    Science.gov (United States)

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

    2014-10-01

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

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

    Science.gov (United States)

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

    2014-10-01

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

  15. Effect of Exogenous Nitric Oxide on Development of Fruits and Vegetables Postharvest Disease Penicillium expansum%外源一氧化氮对果蔬采后病害Penicillium expansum发育的影响

    Institute of Scientific and Technical Information of China (English)

    赖童飞; 刘毅; 任梦; 赖利宇; 周婷

    2013-01-01

    Penicillium expansum是果蔬采后主要的病原真菌,对果蔬的贮藏具有极大的危害,寻找有效的防治方法具有重要的意义.本研究对苹果(Malus domestica)青霉病菌进行了分离及rDNA-ITS法鉴定,确定为P.expansum;利用不同浓度的外源一氧化氮(NO)处理病菌,通过孢子萌发率、芽管长度、菌丝扩展速度等指标以及苹果接种实验,研究了外源NO与P.expansum发育及致病力的关系,并通过进行胞内活性氧水平、蛋白质羰基化、丙二醛(MDA)及ATP含量的检测,对NO的作用机理进行了初步的探索.结果表明,外源NO可以显著抑制P.expansum的发育,且浓度越高抑制作用越强,其抑菌机理可能是通过诱导P.expansum胞内活性氧积累引起氧化损伤.本研究为果蔬采后病原菌的防治提供了新的思路.%Penicillium expansum is a major postharvest pathogen and quite harmful to fruit and vegetable preservation. Therefore, it is necessary to search for an effective control method. In this study, we isolated a P. expansum from naturally infected apples (Malus domestica) and identified it by rDNA-ITS method. The relationship between exogenous nitre oxide (NO) with different concentrations and growth or pathogenicity of P. expansum were evaluated via assessment of germination ratio, germ tube length, mycelium extension speed, and inoculation experiment of apple. In addition, by determining level of reactive oxygen species, carbonylated proteins, and evaluating the content of malondialdehyde (MDA) and ATP, the possible inhibitory mechanism of exogenous NO on P. expansum was explored preliminarily. The results indicated that exogenous NO could inhibit the growth of P. expansum and the behavior was dose-dependent. It was speculated that the inhibitory effect came from accumulation of reactive oxygen species, which led to oxidative damages. This study provides a new approach to control postharvest horticulture pathogens potentially of fruit and

  16. 柑桔黄龙病的鉴定和柯赫氏定理%"Candidatus Liberibacter Species": Without Koch's Postulates Completed, Can the Bacterium be Considered as the Causal Agent of Citrus Huanglongbing (Yellow Shoot Disease) ?

    Institute of Scientific and Technical Information of China (English)

    Chen J; Deng X; Civerolo E L; Lee R F; Jones J B; Zhou C; Hartung J S; Manjunath K L; Brlansky R H

    2011-01-01

    Huanglongbing (HLB, yellow shoot disease) has been a destructive disease of citrus around the world for over a century, yet the etiology of the disease has not been definitively established. Based mainly on assays for 16S rRNA gene sequences, fastidious bacteria known as "Candidatus Liberibacter species" have been .ssociated with HLB. We are concerned that some current literature frequendy refers to "Ca. Liberibacter spp." as the causal or etiological agent of HLB. However, Koch' s postulates, either sensu stricto or modified, have not yet been completely fulfilled to establish that "Ca. Liberibacter spp." are the cause of HLB.Direct pathological interactions between the bacteria and citrus host have not been conclusively documented.We suggest there is a need for the literature to be precise on this point until the etiology of HLB is firmly established.%黄龙(梢)病被认为是世界柑橘生产上的毁灭性病害已超过一个世纪,但该病害的病原学至今还没有清晰地建立起来.根据16S rRNA基因序列分析,一组被称为"Candidatus Liberibacter species"的难培养细菌被认为与黄龙病相关.然而,要确定"Ca.Liberibacter spp."是黄龙病病原的柯赫氏定理并没有真正完成.令我们担忧的是,近年来有些文献频频指出"Ca.Liberibacter spp."是黄龙病的病原,其实该细菌与柑橘寄主的直接病理反应还没有完全确定.我们建议,在黄龙病病原学清楚之前,文献报道在这方面需要有准确的阐述.

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

    Directory of Open Access Journals (Sweden)

    N. de L. Nogueira

    1996-05-01

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

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

    Science.gov (United States)

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

  19. 草莓灰霉病拮抗酵母菌的筛选鉴定及对采后草莓品质的影响%Screening and identification of antagonistic yeast against the gray mould disease and effect on quality of postharvest strawberry

    Institute of Scientific and Technical Information of China (English)

    秦晓杰; 许皎姣; 索娜; 周海莲; 何洋; 肖红梅

    2012-01-01

    从南京市马群草莓生产基地的草莓果实、叶片上分离筛选到一株对灰霉病具有明显抑制效果的拮抗酵母菌N1,结合生理生化特性及26Sr DNA D1/D2区序列分析鉴定其为季也蒙毕赤酵母(Pichia guilliermondii)。通过用不同浓度N1菌悬液处理打孔后的草莓,发现菌悬液浓度越高,抑制效果越好,最佳浓度为5×108CFU/mL,其病斑直径比对照组小了32.3%。桔抗菌N1处理后果实于(2±1)℃、相对湿度(RH)90%-95%下冷藏,结果表明,拮抗酵母N1菌对果实酸含量无显著影响,但能保持草莓果实的光泽和硬度,维持VC含量和可溶性固形物含量,并显著减小了失重率,提高了草莓的冷藏品质,从而显著延长草莓的贮藏寿命。由此推测,该拈抗酵母菌具有很好的商业应用前景。%The antagonistic yeast NI with a high ability of inhibiting the gray mould (Botrytis cinerea)disease on strawberry was isolated from the strawberry fruits and leaves in Nanjing Maqun with in vitro and in vivo methods. This strain was preliminarily identified as Pichia guilliermondii based on the similarity analysis of its physiological- biochemical characteristics and 26S rDNA DI/D2 domain sequence.Pretreatment with different concentrations of N] could decrease the incidence of rot on postharvest strawberry after inoculation with pathogenic fungi Botrytis cinerea.The result showed that the higher concentration of N1 ,the inhibition effect on the gray mould disease was better.The best inhibition concentration of N1 was 5×108CFU/mL which could decrease the incidence of rot to 32. 3% ,compared with rot only inoculating with pathogenic fungi.Postharvest strawberries treated with the antagonist were stored at (2±1 )℃ with RH 90% -95% ,the results showed that the antagonist treatment had little effect on acid content,but could maintain fruit luster,firmness,soluble solid and vitamin C content,also reduce weight

  20. Detection of Liberibacter asiaticus in a single infected Asian citrus psyllid adult or nymph: Impact of dilution with clean Asian citrus psyllids (Diaphorina citri) during extraction

    OpenAIRE

    LeVesque, Cynthia; Kumagai, Lucita; Bloomquist, Cheryl; Keremane, Manjunath; Lee, Richard; Kunta, Madhurababu; da Graça, John V.; Vidalakis, Georgious; Lin, Hong; Morgan, John; Hall, David G.; Polek, MaryLou

    2014-01-01

    Now that the presence of Huanglongbing (HLB) has been confirmed in California, protecting the state’s citrus industry through early detection of disease is essential in curtailing its spread. Because ‘Candidatus Liberibacter asiaticus’ (Las), the putative causal agent of HLB, accumulates in its vector, the Asian citrus psyllid (ACP), Diaphorina citri, Kuwayama, accurate testing of the insect is vital. Due to the fact that insect secondary metabolites interfere with downstream applications (1,...

  1. The science, development, and commercialization of postharvest biocontrol

    Science.gov (United States)

    Postharvest biological control agents as a viable alternative to the use of synthetic chemicals have been the focus of considerable research for the last 30 years by many scientists and several commercial companies worldwide. Several antagonists of postharvest pathogens have been identified and tes...

  2. Integrated Management of Causal Agents of Postharvest Fruit Rot of Apple

    Directory of Open Access Journals (Sweden)

    Mila Grahovac

    2011-01-01

    Full Text Available One of the major causes of poor quality and fruit loss (during storage and transportare diseases caused by phytopathogenic fungi. Economic losses which are the consequenceof the phytopathogenic fungus activity after harvest exceed the losses in the field.Themost important postharvest fungal pathogens of apple fruits are: Botrytis cinerea Pers. exFr., Penicillium expansum (Lk. Thom., Cryptosporiopsis curvispora (Peck. Grem., Colletotrichumgloeosporioides (Penz. Sacc., Monilinia sp., Gloeosporium album Osterw, Alternaria alternata(Fr. Keissler, Cladosporium herbarium Link., Cylindrocarpon mali (Alles. Wollenw., Stemphyliumbotryosum Wallr. The use of available protection technologies can significantly reducelosses caused by pathogens in storage. The concept of integrated pest management (IPMin apple fruits i.e. sustainable approach in control of causal agents of postharvest fruit rot,using cultural, physical, biological and chemical measures, to minimize economic, healthand risks to consumers and environment, is presented in the paper.

  3. Chitosan controls postharvest anthracnose in bell pepper by activating defense-related enzymes.

    Science.gov (United States)

    Edirisinghe, Madushani; Ali, Asgar; Maqbool, Mehdi; Alderson, Peter G

    2014-12-01

    Anthracnose, a postharvest disease caused by the fungus Colletotrichum capsici is the most devastating disease of bell pepper that causes great economic losses especially in tropical climates. Therefore, the objective of this study was to evaluate the antifungal properties of chitosan (low molecular weight from crab shell, Mw: 50 kDa and 75-85 % deacetylated) against anthracnose by inducing defense-related enzymes. The concentrations of 0, 0.5, 1.0, 1.5 and 2.0 % chitosan were used to control the fungus in vitro and postharvest. There was a reduction in C. capsici mycelial growth and the highest chitosan concentration (2.0 %) reduced the growth by 70 % after 7 days incubation. In germination test, the concentration of 1.5 and 2.0 % chitosan reduced spore germination in C. capsici between 80 % and 84 %, respectively. In postharvest trial the concentration of 1.5 % decreased the anthracnose severity in pepper fruit by approximately 76 % after 28 days of storage (10 ± 1 °C; 80 % RH). For enzymatic activities, the concentration of 1.5 and 2.0 % chitosan increased the polyphenol oxidase (PPO), peroxidase (POD) and total phenolics in inoculated bell pepper during storage. Based on these results, the chitosan presents antifungal properties against C. capsici, as well as potential to induce resistance on bell pepper.

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

    Science.gov (United States)

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

  5. A TaqMan PCR method for routine diagnosis of the quarantine fungus guignardia citricarpa on citrus fruit

    NARCIS (Netherlands)

    Gent-Pelzer, van M.P.E.; Brouwershaven, van I.R.; Kox, L.F.F.; Bonants, P.J.M.

    2007-01-01

    With respect to disease risk for the quarantine fungus Guignardia citricarpa on citrus fruit an accurate diagnosis for routine analysis is required. Also, when inspections have to be performed on imported citrus fruits, a fast detection method is urgently needed. A fast automated DNA extraction meth

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

    2016-06-01

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

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

    Science.gov (United States)

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

    2016-06-01

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

  9. Desenvolvimento de um sistema de apoio à decisão para a diagnose de doenças, pragas e distúrbios abióticos dos citros Development of a decision support system for the diagnosis of citrus diseases, pests, and abiotic factors

    Directory of Open Access Journals (Sweden)

    Cleilson do Nascimento Uchôa

    2010-06-01

    Full Text Available A preocupação com a diagnose dos problemas que afetam as plantas cítricas proporcionou ao longo dos anos o acúmulo de conhecimento, que precisava ser organizado e divulgado de forma eficiente e rápida. Dessa forma, objetivou-se com esse trabalho construir uma base de conhecimentos para diagnóstico de doenças bióticas e abióticas dos citros, desenvolver e implementar o sistema de apoio à decisão (SAD e avaliar o sistema. O SAD foi construído utilizando a ferramenta 'Borland Delphi' versão 5. Foram formuladas 562 perguntas, 322 regras e anexadas fotografias para facilitar o diagnóstico de 34 doenças, 40 pragas e 34 distúrbios abióticos dos citros. A avaliação do SAD foi dividida em verificação e validação. Na verificação, o SAD foi submetido a uma análise por meio de questionário a 5 especialistas em citros. A validação do programa foi realizada com quatro grupos, de diferentes níveis de conhecimento (10 pessoas/grupo, tentando diagnosticar corretamente. Obteve-se um acerto de 45,6% dos usuários e 93,6% do SAD. O sistema foi denominado Dr. Citrus (protótipo com registro no INPI n° 014070009188.The concern about the diagnosis of problems affecting citrus led to an accumulation of knowledge over the years. However, such accumulated knowledge needed to be organized and efficiently disseminated. Thus, the aims of this work were to build a knowledge basis for the diagnosis of abiotic and biotic citrus diseases to develop and implement a Decision Support System (DSS and to test and evaluate this system. DSS was built by using the tool 'Borland Delphi' version 5. A total of 562 questions were formulated, including 322 rules, besides photographs to help in the diagnosis of 34 diseases, 40 pests and 34 abiotics disturbances in citrus. DSS evolution was divided into verification and validation. In the verification phase, DSS was analyzed by means of a questionnaire applied to citrus specialists. The program validation phase

  10. 78 FR 8435 - Importation of Fresh Citrus Fruit From Uruguay, Including Citrus Hybrids and Fortunella

    Science.gov (United States)

    2013-02-06

    ... From Uruguay, Including Citrus Hybrids and Fortunella spp., Into the Continental United States AGENCY... citrus fruit, as well as Citrus hybrids and the Citrus-related genus Fortunella, from Uruguay into the... certificate issued by the national plant protection organization of Uruguay with an additional...

  11. Histological Characterization of Rind Oil Spotting Disease in Citrus%柑橘油胞凹陷病组织结构特征的研究

    Institute of Scientific and Technical Information of China (English)

    涂俊凡; 吴黎明; 彭抒昂

    2010-01-01

    以4个柑橘品种奉节脐橙(Citrus sinensis Osbeck cv.Fengjie navel orange)、纽荷尔脐橙(C. sinensis Osbeck cv. Newhall navel orange)、红橘(C.reticulata Blanco cv. Red tangerine)和太田椪柑(C. reticulata Blanco cv. Ota ponkan)为试验材料,采用石蜡切片技术,对果皮油胞凹陷病从轻到重的发展过程进行了研究,了解果皮油胞凹陷病各阶段的果皮组织结构特征.结果表明,果皮油胞凹陷病始于黄皮层内4~7层细胞带,受害部位细胞变扁,原生质体收缩位于细胞中央,但表皮细胞仍排列整齐、紧密;受害部位都始于两油胞之间,受害细胞层有多种形式,有的与果皮表面平行,有的为块状,沿着黄皮层延伸,在正常细胞层之间形成明显的受害区;中期细胞变得狭长,原生质体在细胞壁周围缩成薄薄的一层;后期病害到达表皮细胞,造成胞质降解,但油胞仍然完好;末期油胞上部细胞破裂,部分油胞受到伤害,向内凹陷.

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

    Science.gov (United States)

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

    2005-09-01

    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 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

  13. Toxicity Measurement of Different Fungicides on Citrus Scab Disease%不同杀菌剂对柑橘疮痂病菌的室内毒力测定

    Institute of Scientific and Technical Information of China (English)

    周小燕; 姜于兰

    2011-01-01

    为筛选出对柑橘疮痂病病菌[痂圆孢菌(Sphaceloma.fawcetti Jenkins)]高效、低毒、低残留药剂供生产上使用,采用生长速率法测定了9种杀菌剂对该菌的室内毒力.结果表明,9种药剂对柑橘痂圆孢菌菌丝生长的抑制效果不同,25%咪酰胺EC和10%苯醚甲环唑WG抑菌作用最强,其EC50值分别为0.0267μg/mL和0.036 2μg/mL;60%唑醚·代森联WG次之,其EC50值为1.6101μg/mL,抑菌作用也较强;75%代森锰锌WG和3%中生菌素WP有较好抑菌活性,其EC50值均小于42μg/mL;25%嘧菌酯SC效果最差,EC50值为80274.970 1μg/mL.%In order to screen efficiency, low toxicity and low residual fungicides for the alternant use in citrus production,toxicity measurement of nine fungicides were studied on citrus scab disease with the method of growth rate. The results showed that the nine fungicides had different effects on myeelium growth of Sphaceloma fawcetti. The effects of 25% Prochloraz EC and 10% Difenoconazole WG behaved best, and their ECho were 0.026 7 μg/mL and 0.036 2 μg/mL, respectively;followed by 60% Pyraclostrobin .Metiram WG whose EC50 was 1.610 1 μg/mL. The EC50 of 75% Mancozeb WG and 3%Zhongshengmycin WP was both less than 42 μg/mL; while 25% Chloronitropropane SC behaved worst, and its EC50 was 80 274.970 1 μg/mL.

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

    Science.gov (United States)

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

    2016-05-01

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

  15. A transcriptomic approach highlights induction of secondary metabolism in citrus fruit in response to Penicillium digitatum infection

    Directory of Open Access Journals (Sweden)

    González-Candelas Luis

    2010-08-01

    Full Text Available Abstract Background Postharvest losses of citrus fruit due to green mold decay, caused by the fungus Penicillium digitaum, have a considerable economic impact. However, little is known about the molecular processes underlying the response of citrus fruit to P. digitatum. Results Here we describe the construction of a subtracted cDNA library enriched in citrus genes preferentially expressed in response to pathogen infection followed by cDNA macroarray hybridization to investigate gene expression during the early stages of colonization of the fruit's peel by P. digitatum. Sequence annotation of clones from the subtracted cDNA library revealed that induction of secondary and amino acid metabolisms constitutes the major response of citrus fruits to P. digitatum infection. Macroarray hybridization analysis was conducted with RNA from either control, wounded, ethylene treated or P. digitatum infected fruit. Results indicate an extensive overlap in the response triggered by the three treatments, but also demonstrated specific patterns of gene expression in response to each stimulus. Collectively our data indicate a significant presence of isoprenoid, alkaloid and phenylpropanoid biosynthetic genes in the transcriptomic response of citrus fruits to P. digitatum infection. About half of the genes that are up-regulated in response to pathogen infection are also induced by ethylene, but many examples of ethylene-independent gene regulation were also found. Two notable examples of this regulation pattern are the genes showing homology to a caffeine synthase and a berberine bridge enzyme, two proteins involved in alkaloid biosynthesis, which are among the most induced genes upon P. digitatum infection but are not responsive to ethylene. Conclusions This study provided the first global picture of the gene expression changes in citrus fruit in response to P. digitatum infection, emphasizing differences and commonalities with those triggered by wounding or

  16. CIBMAN: Database exploring Citrus biodiversity of Manipur

    OpenAIRE

    Sanabam, Rakesh; Somkuwar, Bharat Gopalrao; Thingnam, Gourshyam; Moirangthem, Sila; Handique, Pratap Jyoti; Huidrom, Sunitibala

    2012-01-01

    The rich wealth of Citrus genetic resources makes India to enjoy a remarkable position in the “Citrus belt of the world”. We have developed CIBMAN, a unique database on Citrus biodiversity of Manipur which comprises 33 accessions collected through extensive survey for more than three years. CIBMAN provides integrated access to Citrus species through sophisticated web interface which has following capabilities a) morphological details, b) socio-economic details, c) taxonomic details and d) geo...

  17. Citrus breeding, genetics and genomics in Japan

    OpenAIRE

    Omura, Mitsuo; Shimada, Takehiko

    2016-01-01

    Citrus is one of the most cultivated fruits in the world, and satsuma mandarin (Citrus unshiu Marc.) is a major cultivated citrus in Japan. Many excellent cultivars derived from satsuma mandarin have been released through the improvement of mandarins using a conventional breeding method. The citrus breeding program is a lengthy process owing to the long juvenility, and it is predicted that marker-assisted selection (MAS) will overcome the obstacle and improve the efficiency of conventional br...

  18. Effects of chitosan-glucose complex coating on postharvest quality and shelf life of table grapes.

    Science.gov (United States)

    Gao, Pisheng; Zhu, Zhiqiang; Zhang, Ping

    2013-06-01

    Surface coatings and films are prospective alternatives for extending the postharvest life of fresh fruits and vegetables. In this study, freshly harvested grapes were treated with chitosan, glucose, chitosan-glucose complex (CGC), or water (control) for up to 60 days at 0 °C in 95% relative humidity followed by 3 days in the air at 20 °C. The results showed that coated samples were effective in terms of senescence inhibition and postharvest diseases prevention. Chitosan-glucose complex showed better effects on delaying the declines of total soluble solids, ascorbic acid and titratable acidity, decreasing decay and weight loss, suppressing respiration rate, inducing POD and SOD activities, in comparison with pure chitosan or glucose. In addition, CGC coating treatment ensured better berry texture and higher sensory scores, compared with those treated with chitosan or glucose alone. The results indicated that CGC may be a promising strategy for improving the postharvest quality and extending the shelf life of table grapes. PMID:23618282

  19. Soil Micronutrients and Citrus Growth

    Institute of Scientific and Technical Information of China (English)

    OUYANGTAO

    1993-01-01

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

  20. Inhibitory effect of some spice essential oils on Penicillium digitatum causing postharvest rot in citrus

    Directory of Open Access Journals (Sweden)

    Akgül, Attila

    2000-08-01

    Full Text Available In this study to control blue mould caused by Penicillium digitatum, essential oil of cumin was applied with filter paper discs of 6 mm diameter which were soaked in 0,04 ml oil and vapour effect inhibited completely mycelial growth and spore germination of pathogen in vitro. When filter paper discs soaked in essential oils of black thyme, dill, coriander and rosemary were placed on the culture medium (PDA, they had no effect on the mycelial growth. Their vapour effect inhibited mycelial growth of pathogen 85.8%, 82.8%, 80% and 71.4% respectively. Dill and rosemary oils also prevented mycelial colour.En este estudio para controlar las manchas azules causadas por Penicillium digitatum, se aplicó aceite esencial de comino en discos de papel de filtro de 6 mm de diámetro, los cuales fueron empapados en 0,04 ml de aceite y su vapor inhibió completamente el crecimiento micelar y la germinación de esporas del patógeno in vitro. Cuando los discos de papel de filtro empapados en aceites esenciales de tomillo, eneldo, culantro y romero se colocaron sobre el medio de cultivo (PDA, no se observó efecto sobre el crecimiento micelar. Los efectos de sus vapores inhibieron el crecimiento micelar de patógenos en un 85,8%, 82,8%, 80% y 71,4% respectivamente. Los aceites de eneldo y romero también evitaron la aparición del color micelar.

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

  3. Postharvest characteristics of two cultivars of cauliflower

    Directory of Open Access Journals (Sweden)

    Adenilson Mroginski de Souza

    2010-06-01

    Full Text Available The cauliflower has a great economic importance, especially for small producers, and it turns out to be a profitable crop in small areas. However, at postharvest period it is difficult to store it at a given room temperature due to sweating and a heavy breathing process, which leads to a discoloration of the inflorescence. Thus, the current study aimed to characterize the postharvest storage of cauliflower hybrids Snow Mystique and Graffiti kept at room temperature corresponding to an air temperature of 20 ± 2oC and a relative humidity (RH of 75%. Evaluations were made every three days during a period of 12 days of storage. The parameters studied were percentage of weight loss in fresh weight terms, firmness of stem, soluble solids, pH and measurable acidity. By evaluating the results, it was concluded that the cauliflower is not supposed to be stored at an air temperature of 20 ± 2oC and a 75% RH for more than three days, since the inflorescence presented a high water loss through the transpiration process under the environmental conditions in study.

  4. Phytophthora parasitica transcriptome, a new concept in the understanding of the citrus gummosis

    OpenAIRE

    Daniel D. Rosa; Magnólia A. Campos; Maria Luisa P.N. Targon; De Souza, Alessandra A.

    2007-01-01

    Due to the economic importance of gummosis disease for the citriculture, studies on P. parasitica-Citrus interaction comprise a significant part in the Brazilian Citrus genome data bank (CitEST). Among them, two cDNA libraries constructed from two different growth conditions of the P. parasitica pathogen are included which has generated the PP/CitEST database (CitEST - Center APTA Citros Sylvio Moreira/IAC- Millennium Institute). Through this genomic approach and clustering analyses the follo...

  5. An in silico analysis of the key genes involved in flavonoid biosynthesis in Citrus sinensis

    OpenAIRE

    Adriano R. Lucheta; Ana Carla O. Silva-Pinhati; Ana Carolina Basílio-Palmieri; Irving J. Berger; Juliana Freitas-Astúa; Mariângela Cristofani

    2007-01-01

    Citrus species are known by their high content of phenolic compounds, including a wide range of flavonoids. In plants, these compounds are involved in protection against biotic and abiotic stresses, cell structure, UV protection, attraction of pollinators and seed dispersal. In humans, flavonoid consumption has been related to increasing overall health and fighting some important diseases. The goals of this study were to identify expressed sequence tags (EST) in Citrus sinensis (L.) Osbeck co...

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

    Directory of Open Access Journals (Sweden)

    Svetlana Y Folimonova

    2013-04-01

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

  7. Drinking Citrus Fruit Juice Inhibits Vascular Remodeling in Cuff-Induced Vascular Injury Mouse Model

    OpenAIRE

    Ohnishi, Arika; Asayama, Rie; Mogi, Masaki; Nakaoka, Hirotomo; Kan-no, Harumi; Tsukuda, Kana; Chisaka, Toshiyuki; Wang, Xiao-li; Bai, Hui-Yu; Shan, Bao-Shuai; Kukida, Masayoshi; Iwanami, Jun; Horiuchi, Masatsugu

    2015-01-01

    Citrus fruits are thought to have inhibitory effects on oxidative stress, thereby attenuating the onset and progression of cancer and cardiovascular disease; however, there are few reports assessing their effect on vascular remodeling. Here, we investigated the effect of drinking the juice of two different citrus fruits on vascular neointima formation using a cuff-induced vascular injury mouse model. Male C57BL6 mice were divided into five groups as follows: 1) Control (water) (C), 2) 10% Cit...

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

    OpenAIRE

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

    2011-01-01

    During 2008 and 2009, a new disease was noticed in eastern Sicily (Italy) in two re-grafted citrus orchards (Citrus sinensis (L.) Osbeck) on sour orange rootstock. Symptoms consisted of blight of vigorously growing shoots and a sooty canker on shoots and rootstock trunks. A Scytalidium-like fungus was isolated consistently from symptomatic tissues on 2% potato-dextrose agar (PDA). The mycelium was composed of branched, septate, brown hyphae which disarticulated into 0-1-septate phragmospores....

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

    OpenAIRE

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

    2011-01-01

    During 2008 and 2009, a new disease was noticed in eastern Sicily (Italy) in two re-grafted citrus orchards (Citrus sinensis (L.) Osbeck) on sour orange rootstock. Symptoms consisted of blight of vigorously growing shoots and a sooty canker on shoots and rootstock trunks. A Scytalidium-like fungus was isolated consistently from symptomatic tissues on 2% potato-dextrose agar (PDA). The mycelium was composed of branched, septate, brown hyphae which disarticulated into 0-1-septate phragmospores....

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    John S Ramsey

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

  12. 薰衣草精油对樱桃番茄采后黑斑病的抑制活性%Control of black rot disease in postharvest cherry tomato with lavender oil

    Institute of Scientific and Technical Information of China (English)

    任雪艳; 梁卓; 王慧敏; 闫帆; 魏玉荣; 孔庆军

    2014-01-01

    This experiment was conducted to study the inhibitory effect and action mode of lavender oil against black rot in postharvest cherry tomato caused by Alternaria alternata by means of fumigation and direct contact. Lavender oil fumi-gation with the dosage of 5 μl per petri dish or direct contact at 400 μl/L could inhibit the growth of A. alternata complete-ly. The incidences of black rot were reduced by 54% and 60% in post harvest cherry tomatoes fumigated with 100 μl/L lavender oil and directly contacted with 500 μl/L lavender oil respectively. An inhibitory effect of short-time lavender oil treatment was shown on A. alternata while a lethal effect of long-time lavender oil treatment was exhibited.%为薰衣草精油用于防治樱桃番茄采后黑斑病提供依据,研究了薰衣草精油熏蒸和直接接触对病原真菌链格孢( Alternaria alternata)的抑制活性及作用方式。结果表明,在培养基培养试验中,每皿5μl的薰衣草精油熏蒸即可完全抑制病原菌的生长;当400μl/L薰衣草精油直接接触链格孢病原菌时,可完全抑制病原菌的生长。在薰衣草精油对樱桃番茄果实采后黑斑病抑制效果试验中发现,100μl/L精油熏蒸处理果实时,处理组果实发病率比对照组降低54%,用500μl/L精油直接处理果实时,处理组果实发病率则比对照组降低60%。在薰衣草精油对病原真菌链格孢作用方式试验中,薰衣草精油作用时间短时,对链格孢病原菌生长有抑制作用,薰衣草精油作用时间长时(5 d和7 d)对链格孢病原菌有致死效应。

  13. Citrus fruits diseases and insect pest recognition based on multifractal analysis of Fourier transform spectra%椪柑果实病虫害的傅里叶频谱重分形图像识别

    Institute of Scientific and Technical Information of China (English)

    温芝元; 曹乐平

    2013-01-01

    Plant pests and diseases image recognition is one of the key technologies of digital agricultural information collection and processing. Usually, based on pest infestation-like plant, it is carried out according to the size, shape, color, texture, etc., or a combination of several parameters. Machine recognition of diseases and insect pests needs to use digitalized characteristics without overlapping. Multi-fractal analysis of Fourier transform spectra was adopted to investigate the possibility of extraction of damage pattern characteristics for Citrus reticulata Blanco var. Ponkan. First, images of the boundary of a damaged pattern are extracted with an improved watershed algorithm and region merging. Secondly, a Discrete Fourier Transform (DFT) was applied to the damaged fruit image. With reference to the boundary of a damaged pattern, a fruit image magnitude spectrum was extracted. Thirdly, a fruit image magnitude spectrum was multi-fractiously analyzed and the multi-fractal spectrum of DFT magnitude spectrum was quadratic fitted. Height, width, and centroid coordinate of a fitting parabolic section were chosen feature values to identify the diseases and insect damage of fruits, with these three feature values as inputs of a BP neural network identifying diseases and insect damage of Ponkan, and the accuracy was up to 92.67%. Finally, the amplitude spectrum of the Fourier transform was adopted for multifractal analysis and multi-fractal spectrum of a quadratic fit;fit parabola segment height, width, and centroid coordinates were regarded as pests’ Eigen values, and then used as input variables to establish a BP citrus pest identification neural network model for pest identification. Among 5 classes of pests, in 30 groups of test samples, such as Pezothrips Kellyanus, Oxycetonia Jucunda, Oraesia Emarginata, Polyphagotarsonemus Latus, Colletotrichum Gloeoporioides Penz, the highest recognition rate was for Oraesia Emarginata, that is 96.67%, Polyphagotarsonemus

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

    OpenAIRE

    Nociti Letícia A; Rodrigues Neto Julio; Leite Rui P; Nishiyama Milton Y; Laia Marcelo L; Kitajima Elliot W.; Jones Jeffrey B; Gimenez Daniele F; Furlan Luiz R; Ferro Maria I; Ferraz André L; Facincani Agda P; de Souza Robson F; de Oliveira Julio C; de Moraes Fabrício E

    2010-01-01

    Abstract Background Citrus canker is a disease that has severe economic impact on the citrus industry worldwide. There are three types of canker, called A, B, and C. The three types have different phenotypes and affect different citrus species. The causative agent for type A is Xanthomonas citri subsp. citri, whose genome sequence was made available in 2002. Xanthomonas fuscans subsp. aurantifolii strain B causes canker B and Xanthomonas fuscans subsp. aurantifolii strain C causes canker C. R...

  15. Synthesis results from eight years of field testing insecticides against Asian citrus psyllid Diaphorina citri vector of huanglongbing: Considerations and Implications

    OpenAIRE

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

    2014-01-01

    Diaphorina citri also known as Asian citrus psyllid (ACP) vectors Candidatus Liberibacter asiaticus, causal organism of the Asian “huanglongbing” or citrus greening disease and therefore needs to be managed effectively.  Forty-three insecticides containing 39 active ingredients (a.i) recommended or experimental were tested during the growing season in foliar sprays (171 treatments, 35 a.i) targeted at flushing trees and soil applications (26 treatments, 6 a.i) to control ACP in citrus between...

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

    OpenAIRE

    Singh, Jagdeep; Sood, Shailja; Muthuraman, Arunachalam

    2011-01-01

    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 and lipid peroxidation & lipoxygenase inhibitory action of Citrus karna peel extracts were undertaken. Extraction was performed with different solvent...

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

    Science.gov (United States)

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

    2015-09-01

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

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

    Science.gov (United States)

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

    2015-09-01

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

  19. Natural products for cancer-targeted therapy: citrus flavonoids as potent chemopreventive agents.

    Science.gov (United States)

    Meiyanto, Edy; Hermawan, Adam; Anindyajati

    2012-01-01

    Targeted therapy has been a very promising strategy of drug development research. Many molecular mechanims of diseases have been known to be regulated by abundance of proteins, such as receptors and hormones. Chemoprevention for treatment and prevention of diseases are continuously developed. Pre-clinical and clinical studies in chemoprevention field yielded many valuable data in preventing the onset of disease and suppressing the progress of their growth, making chemoprevention a challenging and a very rational strategy in future researches. Natural products being rich of flavonoids are those fruits belong to the genus citrus. Ethanolic extract of Citrus reticulata and Citrus aurantiifolia peels showed anticarcinogenic, antiproliferative, co-chemotherapeutic and estrogenic effects. Several examples of citrus flavonoids that are potential as chemotherapeutic agents are tangeretin, nobiletin, hesperetin, hesperidin, naringenin, and naringin. Those flavonoids have been shown to possess inhibition activity on certain cancer cells' growth through various mechanisms. Moreover, citrus flavonoids also perform promising effect in combination with several chemotherapeutic agents against the growth of cancer cells. Some mechanisms involved in those activities are through cell cycle modulation, antiangiogenic effect, and apoptosis induction. Previous studies showed that tangeretin suppressed the growth of T47D breast cancer cells by inhibiting ERK phosphorylation. While in combination with tamoxifen, doxorubicin, and 5-FU, respectively, it was proven to be synergist on several cancer cells. Hesperidin and naringenin increased cytotoxicitity of doxorubicin on MCF-7 cells and HeLa cells. Besides, citrus flavonoids also performed estrogenic effect in vivo. One example is hesperidin having the ability to decrease the concentration of serum and hepatic lipid and reduce osteoporosis of ovariectomized rats. Those studies showed the great potential of citrus fruits as natural product

  20. Evaluation of citrus fibers as a tablet excipient.

    Science.gov (United States)

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

    2014-04-01

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

  1. Identification of Disease Resistance to Anthracnose and Sooty Mould of the Main Citrus Varieties in Guizhou Province%贵州柑橘主栽种对炭疽病和煤污病的抗性鉴定

    Institute of Scientific and Technical Information of China (English)

    姜于兰; 侯小莉; 谭萍

    2011-01-01

    In order to study the resistance to citrus anthracnose and citrus sooty mould of the seven main citrus varieties in Guizhou Province, for the citrus anthracnose, the methods of the indoor in vitro identification and outdoor field investigation were used. And for the citrus sooty mould, the method of outdoor field investigation was used. The results showed that the strongest resistance variety was Murcott orange, and the most susceptibility variety was Zhuju.%为了解贵州柑橘7个主栽种(椪柑、朱橘、沙田柚、温州蜜橘、南丰蜜桔、纽贺尔脐橙和默科特桔橙)对柑橘炭疽病和煤污病的抗病性,采用室内离体鉴定和田间调查的方法,对柑橘主栽种的炭疽病和煤污病的抗性进行了鉴定.结果表明,默科特桔橙对炭疽病和煤污病的抗性最强,而朱橘最易感这2种病.

  2. Managing postharvest innovation: a review of developments and trends

    OpenAIRE

    Batterink, M.H.; Omta, S.W.F.; Wubben, E.F.M.

    2005-01-01

    Purpose of the review: With the fast developments in technologies, combined with increased global competition and changing customer demands, innovation is increasingly seen as a means for sustainable growth. This paper reviews literature on the management of innovation and the most prominent findings from postharvest innovation practices. Main findings: Three areas of postharvest innovation were identified: product innovation, enablers for fresh foods and quality improvements and netchain inn...

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

  5. Pathotypes and Genetic Diversity of Chinese Collections of Elsinoë fawcettii Causing Citrus Scab

    Institute of Scientific and Technical Information of China (English)

    HOU Xin; HUANG Feng; ZHANG Tian-yuan; XU Jian-guo; Hyde D Kevin; LI Hong-ye

    2014-01-01

    Two scab diseases are currently recognized on citrus:citrus scab, caused by Elsinoë fawcettii, and sweet orange scab, caused by E. australis. Although these pathogens are economically important, there is no molecular data on these species in China. Here we use internal transcribed spacer sequence data to report on host-speciifcity and genetic relationships among 46 isolates collected from the main citrus varieties grown across China. All strains isolated were E. fawcettii. Based on pathogenicity testing on 9 different citrus species, isolates were divided into 11 pathotypes (SM, FBHR, SJCR, SPOJCR, SR, SOJG, SPOJC, SRGC, Lemon and two unnamed pathotypes). SM is a new pathotype, and two isolates did not ift into any of the known pathotypes of E. fawcettii. Inter-simple sequence repeat (ISSR-PCR) assays separated the E. fawcettii isolates into 10 subgroups;the groupings basically corresponded to the pathogenicity test.

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

    Directory of Open Access Journals (Sweden)

    Hebert Adrianto

    2014-03-01

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

  7. PENDIDIKAN DAN PELATIHAN PEMBIBITAN JERUK BEBAS PENYAKIT CVPD (Citrus Vein Phloem Degeneration DI DESA KATUNG KINTAMANI

    Directory of Open Access Journals (Sweden)

    Adiartayasa W

    2012-10-01

    Full Text Available The community service in the form of training about free orange seed of disease CVPD (Citrus Vein Phloem Degenaration was conducted in Katung village, district of Kintamani, Bangli regency on 10 August 2007. The training activity aimed to improve knowledge of farmers about CVPD disease, symptom, transmission, insect vector, and integrated pest management. The topics covered were disease symptoms, and pathogen bacteria, Diaphorina citri are as insect vector infection mechanism, election of free orange mains crops CVPD, disease distribution and integrated management of CVPD. The training was attended by 25 participants from local groups of Katung village. The methods used in this activity were lectures, demonstration and practical work in the citrus field. All participants enthusiastically took part and hoped to have the next intensive training of citrus culture.

  8. Study of packing lines for stone fruits and citrus using two instrumented spheres in some cooperatives in the region of Murcia (Spain).

    OpenAIRE

    Ruiz-Altisent, Margarita; Garcia, F.; Riquelme Ballestero, F.; Barreiro Elorza, Pilar

    1996-01-01

    Two instrumented spheres IS 100 were used to evaluate the quality of post-harvest operations. Results obtained from measurements made with both IS (8.8 cm 0 and 6.2 cm 0) show significant differences. Both IS measure the same values of the same variables for soft materials, but not for hard surfaces. Four packing lines belonging to different cooperatives of the region of Murcia (two for stone fruits and two for citrus) were tested. IS values obtained in transfers belonging to the tested lines...

  9. Effectiveness of Phenolic Compounds against Citrus Green Mould

    OpenAIRE

    Sanzani, Simona M.; Leonardo Schena; Antonio Ippolito

    2014-01-01

    Stored citrus fruit suffer huge losses because of the development of green mould caused by Penicillium digitatum. Usually synthetic fungicides are employed to control this disease, but their use is facing some obstacles, such public concern about possible adverse effects on human and environmental health and the development of resistant pathogen populations. In the present study quercetin, scopoletin and scoparone—phenolic compounds present in several agricultural commodities and associated w...

  10. Evaluation of Citrus Fibers as a Tablet Excipient

    OpenAIRE

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

    2013-01-01

    The consumption of fibers is associated with many health benefits, such as a reduction of cardiovascular and gastrointestinal diseases, control of body weight, and prevention of diabetes. Despite the widespread use of fiber supplements such as capsules or tablets, there is an almost complete lack of information concerning the technological properties of functional fibers used in nutraceutical formulations. The aim of this work was to characterize the technological properties of citrus fibers ...

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

    Science.gov (United States)

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

    2010-01-27

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

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

    Science.gov (United States)

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

    2010-01-27

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

  13. Effect of gamma irradiation and its convergent treatment for control of postharvest Botrytis cinerea of cut roses

    Science.gov (United States)

    Chu, Eun-Hee; Shin, Eun-Jung; Park, Hae-Jun; Jeong, Rae-Dong

    2015-10-01

    Postharvest diseases cause considerable losses to harvested crops. Among them, gray mold (Botrytis cinerea) is a major problem of exporting to cut rose flowers into Korea. Irradiation treatment is an alternative to phytosanitary purposes and a useful nonchemical approach to the control of postharvest diseases. Gamma irradiation was evaluated for its in vitro and in vivo antifungal activity against B. cinerea on cut rose varieties, 'Shooting Star' and 'Babe'. The irradiating dose required to reduce the population by 90%, D10, was 0.99 kGy. Gamma irradiation showed complete inhibition of spore germination and mycelial growth of B. cinerea, especially 4.0 kGy in vitro. Antifungal activity of gamma irradiation on rose B. cinerea is a dose-dependent manner. A significant phytotoxicity such as bent neck in cut rose quality was shown from gamma irradiation at over 0.4 kGy (pcontrol the postharvest diseases in cut rose flowers, and will provide a promising technology for horticulture products for exportation.

  14. Characterization of a recombinant Cathepsin B-Like cysteine peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae): A putative target control of citrus huanglongbing

    Science.gov (United States)

    Huanglongbing (HLB) is one of the most destructive disease affecting citrus plants. The causal agent is associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas) spread by the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae). Among the control strategies for H...

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

    Science.gov (United States)

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

  16. Acquisition, Replication and Inoculation of Candidatus Liberibacter asiaticus following Various Acquisition Periods on Huanglongbing-Infected Citrus by Nymphs and Adults of the Asian Citrus Psyllid.

    Science.gov (United States)

    Ammar, El-Desouky; Ramos, John E; Hall, David G; Dawson, William O; Shatters, Robert G

    2016-01-01

    The Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), is the primary vector of Candidatus Liberibacter asiaticus (Las) implicated as causative agent of citrus huanglongbing (citrus greening), currently the most serious citrus disease worldwide. Las is transmitted by D. citri in a persistent-circulative manner, but the question of replication of this bacterium in its psyllid vector has not been resolved. Thus, we studied the effects of the acquisition access period (AAP) by nymphs and adults of D. citri on Las acquisition, multiplication and inoculation/transmission. D. citri nymphs or adults (previously non-exposed to Las) were caged on Las-infected citrus plants for an AAP of 1, 7 or 14 days. These 'Las-exposed' psyllids were then transferred weekly to healthy citrus or orange jasmine plants, and sampled via quantitative polymerase chain reaction (qPCR) analysis 1-42 days post-first access to diseased plants (padp); all tested nymphs became adults 7-14 days padp. Our results indicate that following 1 or 7 day AAP as nymphs 49-59% of Las-exposed psyllids became Las-infected (qPCR-positive), whereas only 8-29% of the psyllids were infected following 1-14 day AAP as adults. Q-PCR analysis also indicated that Las titer in the Las-exposed psyllids (relative to that of the psyllid S20 ribosomal protein gene) was: 1) significantly higher, and increasing at a faster rate, following Las acquisition as nymphs compared to that following Las acquisition as adults; 2) higher as post-acquisition time of psyllids on healthy plants increased reaching a peak at 14-28 days padp for nymphs and 21-35 days padp for adults, with Las titer decreasing or fluctuating after that; 3) higher with longer AAP on infected plants, especially with acquisition as adults. Our results strongly suggest that Las multiplies in both nymphs and adults of D. citri but attains much higher levels in a shorter period of time post-acquisition when acquired by nymphs than when acquired by adults

  17. Acquisition, Replication and Inoculation of Candidatus Liberibacter asiaticus following Various Acquisition Periods on Huanglongbing-Infected Citrus by Nymphs and Adults of the Asian Citrus Psyllid.

    Directory of Open Access Journals (Sweden)

    El-Desouky Ammar

    Full Text Available The Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae, is the primary vector of Candidatus Liberibacter asiaticus (Las implicated as causative agent of citrus huanglongbing (citrus greening, currently the most serious citrus disease worldwide. Las is transmitted by D. citri in a persistent-circulative manner, but the question of replication of this bacterium in its psyllid vector has not been resolved. Thus, we studied the effects of the acquisition access period (AAP by nymphs and adults of D. citri on Las acquisition, multiplication and inoculation/transmission. D. citri nymphs or adults (previously non-exposed to Las were caged on Las-infected citrus plants for an AAP of 1, 7 or 14 days. These 'Las-exposed' psyllids were then transferred weekly to healthy citrus or orange jasmine plants, and sampled via quantitative polymerase chain reaction (qPCR analysis 1-42 days post-first access to diseased plants (padp; all tested nymphs became adults 7-14 days padp. Our results indicate that following 1 or 7 day AAP as nymphs 49-59% of Las-exposed psyllids became Las-infected (qPCR-positive, whereas only 8-29% of the psyllids were infected following 1-14 day AAP as adults. Q-PCR analysis also indicated that Las titer in the Las-exposed psyllids (relative to that of the psyllid S20 ribosomal protein gene was: 1 significantly higher, and increasing at a faster rate, following Las acquisition as nymphs compared to that following Las acquisition as adults; 2 higher as post-acquisition time of psyllids on healthy plants increased reaching a peak at 14-28 days padp for nymphs and 21-35 days padp for adults, with Las titer decreasing or fluctuating after that; 3 higher with longer AAP on infected plants, especially with acquisition as adults. Our results strongly suggest that Las multiplies in both nymphs and adults of D. citri but attains much higher levels in a shorter period of time post-acquisition when acquired by nymphs than when acquired by

  18. Acquisition, Replication and Inoculation of Candidatus Liberibacter asiaticus following Various Acquisition Periods on Huanglongbing-Infected Citrus by Nymphs and Adults of the Asian Citrus Psyllid.

    Science.gov (United States)

    Ammar, El-Desouky; Ramos, John E; Hall, David G; Dawson, William O; Shatters, Robert G

    2016-01-01

    The Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), is the primary vector of Candidatus Liberibacter asiaticus (Las) implicated as causative agent of citrus huanglongbing (citrus greening), currently the most serious citrus disease worldwide. Las is transmitted by D. citri in a persistent-circulative manner, but the question of replication of this bacterium in its psyllid vector has not been resolved. Thus, we studied the effects of the acquisition access period (AAP) by nymphs and adults of D. citri on Las acquisition, multiplication and inoculation/transmission. D. citri nymphs or adults (previously non-exposed to Las) were caged on Las-infected citrus plants for an AAP of 1, 7 or 14 days. These 'Las-exposed' psyllids were then transferred weekly to healthy citrus or orange jasmine plants, and sampled via quantitative polymerase chain reaction (qPCR) analysis 1-42 days post-first access to diseased plants (padp); all tested nymphs became adults 7-14 days padp. Our results indicate that following 1 or 7 day AAP as nymphs 49-59% of Las-exposed psyllids became Las-infected (qPCR-positive), whereas only 8-29% of the psyllids were infected following 1-14 day AAP as adults. Q-PCR analysis also indicated that Las titer in the Las-exposed psyllids (relative to that of the psyllid S20 ribosomal protein gene) was: 1) significantly higher, and increasing at a faster rate, following Las acquisition as nymphs compared to that following Las acquisition as adults; 2) higher as post-acquisition time of psyllids on healthy plants increased reaching a peak at 14-28 days padp for nymphs and 21-35 days padp for adults, with Las titer decreasing or fluctuating after that; 3) higher with longer AAP on infected plants, especially with acquisition as adults. Our results strongly suggest that Las multiplies in both nymphs and adults of D. citri but attains much higher levels in a shorter period of time post-acquisition when acquired by nymphs than when acquired by adults

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

    Science.gov (United States)

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

    2009-02-01

    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 citri and thereby reduce psyllid populations and spread of citrus greening disease.

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

    Science.gov (United States)

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

    2014-12-01

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

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

    Science.gov (United States)

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

    2014-12-01

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

  2. Enhancing Florida strawberry shelf life using peroxiacetic acid pre-harvest treatments and postharvest edible coatings

    Science.gov (United States)

    Strawberry is an important fruit crop in Florida. Yearly losses can be attributed to pre- and postharvest decay caused by Botrytis cinerea, and postharvest decay due primarily to Rhizopus stolonifer. Postharvest applications of edible coatings and sanitizers were tested. Among them, a medium-dens...

  3. Signaling pathways in a Citrus EST database

    OpenAIRE

    Angela Mehta; Marilia Santos Silva; Simone Guidetti-Gonzalez; Helaine Carrer; Marco Aurélio Takita; Natália F. Martins

    2007-01-01

    Citrus spp. are economically important crops, which in Brazil are grown mainly in the State of São Paulo. Citrus cultures are attacked by several pathogens, causing severe yield losses. In order to better understand this culture, the Millenium Project (IAC Cordeirópolis) was launched in order to sequence Citrus ESTs (expressed sequence tags) from different tissues, including leaf, bark, fruit, root and flower. Plants were submitted to biotic and abiotic stresses and investigated under differe...

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

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

    2008-11-01

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

  6. Bionomics of Asian Citrus Psyllid (Hemiptera: Liviidae) Associated with Orange Jasmine Hedges in Southeast Central Florida, with Special Reference to Biological Control by Tamarixia radiata.

    Science.gov (United States)

    Hall, David G; Rohrig, Eric

    2015-06-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama, is an important pest in Florida because it transmits bacteria responsible for citrus huanglongbing disease. In addition to infesting citrus, orange jasmine (Murraya exotica L.) is one of Asian citrus psyllid's preferred host plants and is widely grown as an ornamental hedge. We report on Asian citrus psyllid bionomics over three years at five urban plantings of orange jasmine and on biological control of Asian citrus psyllid by a parasitoid Tamarixia radiata (Waterston). T. radiata had been released in Florida shortly after Asian citrus psyllid was first found, and the parasitoid was known to be established at each planting. Additionally, three new T. radiata haplotypes were released every 3 wk at three plantings during the first study year (one haplotype per planting, over all releases an average of 17 parasitoids per linear meter of hedge); all three haplotypes were released at a fourth planting beginning midway through the study (over all releases, an average combined total of 202 parasitoids per linear meter of hedge). Asian citrus psyllid populations were present year-round at each planting, often at large levels. Such plantings may pose risk to commercial citrus as Asian citrus psyllid reservoirs. Releases of the new haplotypes did not cause any measurable reduction in Asian citrus psyllid population levels during the study, and ironically percentage parasitism was generally highest at a planting where no releases were made. Higher release rates might have been more effective. The probability is discussed that repetitive pruning of orange jasmine reduced the full potential of T. radiata against Asian citrus psyllid in this study. PMID:26470246

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    El-Desouky Ammar

    Full Text Available 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.

  9. Antibacterial activity of Citrus limonum fruit juice extract.

    Science.gov (United States)

    Okeke, Malachy Ifeanyi; Okoli, Arinze Stanley; Eze, Edith Nneka; Ekwume, Grace Chinwe; Okosa, Evangelin Uchena; Iroegbu, Christian Ukwuoma

    2015-09-01

    The fruit juice extract of Citrus limonum was investigated for antibacterial activity. The antibacterial activity of the extract on ten strains of bacteria was determined by both agar well diffusion and macro-broth dilution methods. The extract was variously bacteriostatic and bactericidal against Bacillussubtilis ATCC 6051, Staphylococcus aureus ATCC 12600, Escherichia coli ATCC 11775, Pseudomonas aeruginosa ATCC 10145 as well as locally isolated clinical strains of the above bacteria and Salmonella kintambo (Human: 13, 23: mt:-), Salmonella typhi and Proteus sp. The MICs ranged from 0.78 mg/ml to 50mg/ml; MBCs, 25.0mg/ml to >100mg/ml and MBC/MIC ratios 2.0 to >16.0. These results provide scientific justification for the medicinal use of Citrus limonum fruit juice by Nigerian herbalists in the treatment of diseases in which strains of the test organisms have been implicated as etiologic agents. PMID:26408878

  10. Biological and physical approaches to improve induced resistance against green mold of stored citrus fruit.

    Science.gov (United States)

    Arras, G; Dhallewin, G; Petretto, A; Marceddu, S; Loche, M; Agabbio, M

    2005-01-01

    Health and environmental concerns have point out the need to improve or change several manufacturing steps in the food chain. In this context particular attention should be given to the technologies involved in fruits and vegetables production. Nearly all fresh fruit and vegetables are subjected to different periods of storage and/or shelf-life before of their consumption. This implies the need to protect the commodities from microbial spoilage. Some Citrus species (e.g. lemon and grapefruit) may be stored for several months before consumption and then post-harvest treatments are essential to contain green (Penicillium digitatum) and blue (P. italicum) moulds. Alternative approaches to chemicals usually have a lower efficacy in containing rots but fulfill the consumer's expectation. Among the alternative strategies, the improvement of host natural resistance is promising. In this regard, we report some results concerning the use of biotic (yeast) and abiotic agents as inducers of phytoalexin (i.e. scoparone and/or scopoletin) accumulation in Citrus rind and its importance in the control of fungal decay. In all experiments the inducers were applied on fruits before or 24 h after inoculation with P. digitatum and the rot severity was monitored 7 days later. The accumulation of phytoalexins was monitored according to a standard methodology by HPLC. In all experiments a positive correlation was found between increase of the phytoalexin scoparone in host tissue and reduction of decay.

  11. Microarray analysis of Etrog citron (Citrus medica L.) reveals changes in chloroplast, cell wall, peroxidase and symporter activities in response to viroid infection.

    Science.gov (United States)

    Rizza, Serena; Conesa, Ana; Juarez, José; Catara, Antonino; Navarro, Luis; Duran-Vila, Nuria; Ancillo, Gema

    2012-10-01

    Viroids are small (246-401 nucleotides), single-stranded, circular RNA molecules that infect several crop plants and can cause diseases of economic importance. Citrus are the hosts in which the largest number of viroids have been identified. Citrus exocortis viroid (CEVd), the causal agent of citrus exocortis disease, induces considerable losses in citrus crops. Changes in the gene expression profile during the early (pre-symptomatic) and late (post-symptomatic) stages of Etrog citron infected with CEVd were investigated using a citrus cDNA microarray. MaSigPro analysis was performed and, on the basis of gene expression profiles as a function of the time after infection, the differentially expressed genes were classified into five clusters. FatiScan analysis revealed significant enrichment of functional categories for each cluster, indicating that viroid infection triggers important changes in chloroplast, cell wall, peroxidase and symporter activities.

  12. CONTROL OF POSTHARVEST TOMATO ROT BY SPORE SUSPENSION AND ANTIFUNGAL METABOLITES OF TRICHODERMA HARZIANUM

    Directory of Open Access Journals (Sweden)

    Momein H. El-Katatny

    2012-06-01

    Full Text Available Rot of cherry tomato (Lycopersicon esculentum fruits caused by several fungal pathogens is a detrimental disease leading to substantial yield loses worldwide. Alternaria isolates were the most common fungal species isolated from healthy or rotten fruits. Trichoderma harzianum spore suspension and culture filtrate were tested for their antagonistic activity on controlling tomato fruit rot. T. harzianum isolates suppressed or interfered with the growth of different postharvest tomato fungal pathogens albeit at different degrees. Their culture filtrate inhibited pathogen spore germination possibly due to the released extracellular diffusible metabolite(s. Besides, aberrant morphology of conidia was observed with deformation of hyphal tips. Furthermore, the resulting mycelia appeared desiccated with coagulated protoplasm leading to complete collapse of protoplasm in presence of T. harzianum culture filtrate. Application of T. harzianum spores to tomato fruits decreased disease severity significantly with the most profound effect at higher spore concentrations (108 cells per ml. Similarly, culture filtrate of T. harzianum prevented pathogen spore germination on the surface of tomato fruits leading to decreased incidence of rot symptoms at high culture filtrate concentrations. This work provides strong evidence that T. harzianum is a competent antagonist and its spore suspension and culture filtrate can be used efficiently to control postharvest tomato rot.

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

    Science.gov (United States)

    Sujitha, Mohanan V.; Kannan, Soundarapandian

    2013-02-01

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

  14. In Vitro and In Vivo Antibacterial Activity of Some Organic and Inorganic Salts Against Asiatic Citrus Canker Agent Xanthomonas Citri Subsp. Citri

    Directory of Open Access Journals (Sweden)

    Vahideh Hasabi

    2014-06-01

    Full Text Available Asiatic citrus canker caused by Xanthomonas citri subsp. citri is becoming a disease of high economic impact, affecting all types of important citrus crops. In this study, the potential antibacterial activity of ten organic and inorganic salts on X. citri subsp. citri and on citrus canker disease development was evaluated. Among the salt compounds, copper, iron and zinc inorganic salts particularly zinc (with the highest diameter of inhibition, the lowest MIC and MBC values and the highest bacterial growth inhibitory effect had direct antibacterial activity and strongly reduced the development of canker disease and bacterial population of lime plants.

  15. Effect of chitosan coatings on postharvest green asparagus quality.

    Science.gov (United States)

    Qiu, Miao; Jiang, Hengjun; Ren, Gerui; Huang, Jianying; Wang, Xiangyang

    2013-02-15

    Fresh postharvest green asparagus rapidly deteriorate due to its high respiration rate. The main benefits of edible active coatings are their edible characteristics, biodegradability and increase in food safety. In this study, the quality of the edible coatings based on 0.50%, 0.25% high-molecular weight chitosan (H-chitosan), and 0.50%, 0.25% low-molecular weight chitosan (L-chitosan) on postharvest green asparagus was investigated. On the basis of the results obtained, 0.25% H-chitosan and 0.50% L-chitosan treatments ensured lower color variation, less weight loss and less ascorbic acid, decrease presenting better quality of asparagus than other concentrations of chitosan treatments and the control during the cold storage, and prolonging a shelf life of postharvest green asparagus.

  16. Understanding the physiology of postharvest needle abscission in balsam fir

    Directory of Open Access Journals (Sweden)

    Mason Thane Macdonald

    2015-11-01

    Full Text Available Balsam fir (Abies balsamea trees are commonly used as a specialty horticultural species for Christmas trees and associated greenery in eastern Canada and United States. Postharvest needle abscission has always been a problem, but is becoming an even bigger challenge in recent years presumably due to increased autumn temperatures and earlier harvesting practices. An increased understanding of postharvest abscission physiology in balsam fir may benefit the Christmas tree industry while simultaneously advancing our knowledge in senescence and abscission of conifers in general. Our paper describes the dynamics of needle abscission in balsam fir while identifying key factors that modify abscission patterns. Concepts such as genotypic abscission resistance, nutrition, environmental factors, and postharvest changes in water conductance and hormone evolution are discussed as they relate to our understanding of the balsam fir abscission physiology. Our paper ultimately proposes a pathway for needle abscission via ethylene and also suggests other potential alternative pathways based on our current understanding.

  17. Alternative methods to control postharvest decay caused by Penicillium expansum in plums (Prunus domestica L.).

    Science.gov (United States)

    Molinu, M G; Pani, G; Venditti, T; Dore, A; Ladu, G; D'Hallewin, G

    2012-01-01

    In the latest years, investigation on postharvest treatments has been increasingly addressed to preserve human health and environment safeguard. Several preservative compounds, physical treatments and biological control agents to restrain postharvest pathogens on horticultural products have been widely studied. Among them potassium sorbate (KS) has been generally recognized as safe for use in foods and personal care products. It acts as microbial growth inhibitor and fungistatic agent in foods, including vegetable and fruit products. The efficacy of KS, used alone or combined with heat treatments or biocontrol agents, has been demonstrated in Citrus and stone fruits. Here we report the results of 3 experiments aimed at controlling Penicillium expansum Link decay with the use of KS on a yellow ('Shiro') and a red ('Sanguigna di Bosa II', from the Sardinian germplasm) plum cultivar. An integrated approach, combining ultrasounds (US) as a physical mean and KS solutions at different concentrations, has been employed. In the first experiment, 360 fruits were wounded twice and divided into 6 sets (6 x 60), three of which were inoculated with an isolate of P. expansum (20 microl of a 10(5) cfu x mL(-1)). Then, 180 fruit (half inoculated) were treated by pipetting into each wound 20 microl of a KS solution containing 0, 1.5 or 3% (w/v), respectively. In exp. 2, all fruit (number) was wounded and inoculated, and after 24 h treated by immersion (1 min) into solutions containing 0, 1.5 or 3% (w/v) of SK, with or without the use of US. In exp. 3, wounded fruits were treated by immersion or sonication like in exp. 2, while inoculation took place after 24 h. Then, plums were kept at 25 degrees C and 75-80% RH and the infection degree was monitored after 3 and 6 days. In both cultivars, the 1.5% KS solution significantly reduced the natural infection, while the 3% KS solution resulted effective only on the red one. Moreover, the 1.5% solution was effective in controlling decay of

  18. Digital Gene Expression Analysis of Ponkan Mandarin (Citrus reticulata Blanco) in Response to Asia Citrus Psyllid-Vectored Huanglongbing Infection.

    Science.gov (United States)

    Zhong, Yun; Cheng, Chunzhen; Jiang, Bo; Jiang, Nonghui; Zhang, Yongyan; Hu, Minlun; Zhong, Guangyan

    2016-01-01

    Citrus Huanglongbing (HLB), the most destructive citrus disease, can be transmitted by psyllids and diseased budwoods. Although the final symptoms of the two main HLB transmission ways were similar and hard to distinguish, the host responses might be different. In this study, the global gene changes in leaves of ponkan (Citrus reticulata) mandarin trees following psyllid-transmission of HLB were analyzed at the early symptomatic stage (13 weeks post inoculation, wpi) and late symptomatic stage (26 wpi) using digital gene expression (DGE) profiling. At 13 wpi, 2452 genes were downregulated while only 604 genes were upregulated in HLB infected ponkan leaves but no pathway enrichment was identified. Gene function analysis showed impairment in defense at the early stage of infection. At late stage of 26 wpi, however, differentially expressed genes (DEGs) involved in carbohydrate metabolism, plant defense, hormone signaling, secondary metabolism, transcription regulation were overwhelmingly upregulated, indicating that the defense reactions were eventually activated. The results indicated that HLB bacterial infection significantly influenced ponkan gene expression, and a delayed response of the host to the fast growing bacteria might be responsible for its failure in fighting against the bacteria. PMID:27384559

  19. Digital Gene Expression Analysis of Ponkan Mandarin (Citrus reticulata Blanco in Response to Asia Citrus Psyllid-Vectored Huanglongbing Infection

    Directory of Open Access Journals (Sweden)

    Yun Zhong

    2016-07-01

    Full Text Available Citrus Huanglongbing (HLB, the most destructive citrus disease, can be transmitted by psyllids and diseased budwoods. Although the final symptoms of the two main HLB transmission ways were similar and hard to distinguish, the host responses might be different. In this study, the global gene changes in leaves of ponkan (Citrus reticulata mandarin trees following psyllid-transmission of HLB were analyzed at the early symptomatic stage (13 weeks post inoculation, wpi and late symptomatic stage (26 wpi using digital gene expression (DGE profiling. At 13 wpi, 2452 genes were downregulated while only 604 genes were upregulated in HLB infected ponkan leaves but no pathway enrichment was identified. Gene function analysis showed impairment in defense at the early stage of infection. At late stage of 26 wpi, however, differentially expressed genes (DEGs involved in carbohydrate metabolism, plant defense, hormone signaling, secondary metabolism, transcription regulation were overwhelmingly upregulated, indicating that the defense reactions were eventually activated. The results indicated that HLB bacterial infection significantly influenced ponkan gene expression, and a delayed response of the host to the fast growing bacteria might be responsible for its failure in fighting against the bacteria.

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

    Directory of Open Access Journals (Sweden)

    Hajivand Shokrollah

    2009-01-01

    Full Text Available 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 transmission and HLB pathogen movement to find a way for control or reduce the severity of HLB on the field. The study was conducted to detect HLB pathogen in seeds of Citrus, to determine pathogen movement in citrus seedling after infection and to detect the HLB pathogen in citrus roots. Approach: Seeds of Citrus reticulata cv. Limau Madu were collected from infected orchard and were germinated in screenhouse condition. The seeds of Citrus reticlata cv. L. Madu were planted in screenhouse too for HLB pathogen movement and HLB detection in roots. The seedlings were inoculated using infected grafting methods. Results: HLB was not amplified in new seedlings after germination. HLB moved slowly reaching up to 1.5 cm after 2 weeks, 1.5-4.5 cm after eight weeks and detected on 4.5-9 cm after 14 weeks below the grafting area. HLB was also detected up to 9-15 cm after 16 weeks, 15-24 cm after twenty weeks, 24-28.5 cm after 22 weeks and 28.5-30 cm after 24 weeks below the grafting area. Conclusion: Base on conventional PCR test, HLB disease in citrus is not seed borne and it can reach to the roots 26 weeks after inoculation.

  1. Extension of Small-Scale Postharvest Horticulture Technologies—A Model Training and Services Center

    OpenAIRE

    Lisa Kitinoja; Diane M. Barrett

    2015-01-01

    A pilot Postharvest Training and Services Center (PTSC) was launched in October 2012 in Arusha, Tanzania as part of a United States Agency for International Development (USAID) funded project. The five key components of the PTSC are (1) training of postharvest trainers, (2) postharvest training and demonstrations for local small-scale clientele, (3) adaptive research, (4) postharvest services, and (5) retail sales of postharvest tools and supplies. During the years of 2011–2012, a one year ...

  2. Selected Activities of Citrus Maxima Merr. Fruits on Human Endothelial Cells: Enhancing Cell Migration and Delaying Cellular Aging

    OpenAIRE

    Paiwan Buachan; Linda Chularojmontri; Wattanapitayakul, Suvara K.

    2014-01-01

    Endothelial injury and damage as well as accumulated reactive oxygen species (ROS) in aging play a significant role in the development of cardiovascular disease (CVD). Recent studies show an association of high citrus fruit intake with a lower risk of CVD and stroke but the mechanisms involved are not fully understood. This study investigated the effects of pummelo (Citrus maxima Merr. var. Tubtim Siam, CM) fruit extract on human umbilical vein endothelial cell (HUVECs) migration and aging. T...

  3. Citrus reticulata’s Peels Modulate Blood Cholesterol Profile and IncreaseBone Density of Ovariectomized Rats

    OpenAIRE

    Rosa Adelina; Maria Dwi Supriyati; Dwi Ana Nawangsari; Riris I Jenie; Edy Meiyanto

    2015-01-01

    Hormon Replacement Therapy is a common therapy for estrogen deficiency but in other side it will increase the risk of cardiovascular disease. Another alternative therapy which relatively more safe is using phytoestrogen. The Citrus reticulata’s peel contain flavanone and polimethoxyflavone which are suspected to give estrogenic effect, therefore it is potential to be used as phytoestrogen.The purpose of this study was to examine the estrogenic effect of Citrus reticulata’s...

  4. Complex history of admixture during citrus domestication revealed by genome analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wu, G. Albert; Prochnik, Simon; Jenkins, Jerry; Salse, Jerome; Hellsten, Uffe; Murat, Florent; Perrier, Xavier; Ruiz, Manuel; Scalabrin, Simone; Terol, Javier; Takita, Marco Aur& #233; lio,; Labadie, Karine; Poulain, Julie; Couloux, Arnaud; Jabbari, Kamel; Cattonaro, Federica; Fabbro, Cristian Del; Pinosio, Sara; Zuccolo, Andrea; Chapman, Jarrod; Grimwood, Jane; Tadeo, Francisco; Estornell, Leandro H.; Mu?oz-Sanz, Juan V.; Ibanez, Victoria; Herrero-Ortega, Amparo; Aleza, Pablo; P& #233; rez, Juli& #225; n P& #233; rez,; Ramon, Daniel; Brunel, Dominique; Luro, Francois; Chen, Chunxian; Farmerie, William G.; Desany, Brian; Kodira, Chinnappa; Mohiuddin, Mohammed; Harkins, Tim; Fredrikson, Karin; Burns, Paul; Lomsadze, Alexandre; Borodovsky, Mark; Reforgiato, Giuseppe; Freitas-Astua, 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

    2014-06-30

    vulnerable to disease outbreaks, including citrus greening disease (also known as Huanglongbing) that is rapidly spreading throughout the world's major citrus producing regions1. Understanding the population genomics and domestication of citrus will enable strategies for improvements to citrus including resistance to greening and other diseases. The domestication and distribution of edible citrus types began several thousand years ago in Southeast Asia and spread globally following ancient land and sea routes. The lineages that gave rise to most modern cultivated varieties, however, are lost in undocumented antiquity, and their identities remain controversial2, 3. Several features of Citrus biology and cultivation make deciphering these origins difficult. Cultivated varieties are typically propagated clonally by grafting and through asexual seed production (apomixis via nucellar polyembryony) to maintain desirable combinations of traits (Fig. 1). Thus many important cultivar groups have characteristic basic genotypes that presumably arose through interspecific hybridization and/or successive introgressive hybridizations of wild ancestral species. These domestication events predated the global expansion of citrus cultivation by hundreds or perhaps thousands of years, with no record of the domestication process. Diversity within such groups arises through accumulated somatic mutations, generally without sexual recombination, either as limb sports on trees or variants among apomictic seedling progeny. Two wild species are believed to have contributed to domesticated pummelos, mandarins and oranges. Based on morphology and genetic markers, pummelos have generally been identified with the wild species C. maxima (Burm.) Merrill that is indigenous to Southeast Asia. Although mandarins are similarly widely identified with the species C. reticulata Blanco 4-6, wild populations of C. reticulata have not been definitively described. Various authors have taken dif

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

    Science.gov (United States)

    2010-01-01

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

  6. Rapid cyling plant breeding in citrus

    Science.gov (United States)

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

  7. Cryopreservation and Cryotherapy of Citrus Cultivars

    Science.gov (United States)

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

  8. Resistance and tolerance to Huanglongbing in citrus

    Science.gov (United States)

    The Stover-led research team focuses on developing improved citrus scion varieties, through both conventional breeding and transgenics, with special attention to confronting the threat of citrus huanglongbing (HLB). Collaborations are underway with more than 20 research groups around the world to ha...

  9. 不同剂量短波紫外线照射对采后番茄后熟和发病的影响%Effect of UV-C Light Irradiation on Ripening and Disease Infection of Postharvest Tomato

    Institute of Scientific and Technical Information of China (English)

    荣瑞芬; 冯双庆

    2001-01-01

    给采后绿熟番茄照射不同剂量短波紫外线并人工接种交链孢霉,测定其呼吸和乙烯产生速率、转色及发病指标,进行了贮藏保鲜效果分析。结果表明2.4~3.6 kJ.m-2照射剂量能推迟呼吸及乙烯释放高峰1~3 d,延缓番茄的成熟和转色,控制贮期病害发生。%After being irradiated with UV-C light of various dosages and artificially inoculated with Alternaria alternaria artifitially, mature-green tomato were examined with respect to the preservation effect and disease resistance in terms of the index of respiration rate, ethylene production, color development and infection. The results showed that the respiration rate and ethylene production of fruit irradiated with UV-C light of 2.4~3.6 kJ.m-2 doses were delayed 1~3 days, the ripening and color development were retarded and the disease infection was reduced.

  10. RATIONAL TECHNOLOGIES OF SUNFLOWER SEEDS POST-HARVEST PROCESSING

    Directory of Open Access Journals (Sweden)

    Priporov I. E.

    2015-10-01

    Full Text Available The aim of the research is the determination of rational technology of post-harvest treatment of seeds of sunflower. Existing technologies that are implemented in grain cleaning units and complexes for the preparation of seed material type GCM (Voronezhselmash, "Polyma" (Belarus and others perform seed treatment by sequential processing on all cleaning machines. Return at any point not provided, it is necessary to conduct repeated handling throughout the chain of cars that leads to the reduction of seed yield, decreased performance and increased injury to seed. Research Institute of oil crops designed container technology in universal seed cleaning complex, eliminates these disadvantages and allows finishing the processing of seed material at the time of matching seeds with the requirements of GOST at any stage. In seed output pneumatic sorting machines MOS-9N, which is seed cleaning complex that contained diseased seeds that differ from healthy seeds by color and lowered their quality. To improve the quality of seed material was applied photoelectron separator F 5.1, followed by separation of sunflower seeds on the dimension fraction (Ø7-Ø8 mm, Ø8-Ø9мм. In the result of the research container technology with subsequent fractionation of sunflower seeds on the separator at the final stage of their processing improves the yield of highly certified seeds from 92.90 to 93.20 % compared 91,20 % (without fractionation and reduce the content of their departure from 68,83 to 65,60 % compared 85,52 % (without fractionation depending on size fraction

  11. Shoot-tip Grafting of Late-ripening Tangan(Citrus tankan Tanaka) and Identification of Virus Diseases%迟熟蕉柑茎尖嫁接及其病毒鉴定

    Institute of Scientific and Technical Information of China (English)

    王明召; 区善汉; 娄兵海; 刘升球; 梅正敏; 陈贵峰; 麦适秋; 陈宜超; 莫健生

    2009-01-01

    采用田间结果树上的芽作为接穗进行茎尖嫁接,最终获得7株茎尖嫁接苗.对所获得的茎尖嫁接苗,应用指示植物腊斯克枳橙、墨西哥来檬和伊特洛格香橼亚利桑那861-S-1分别鉴定柑橘碎叶病、衰退病和裂皮病,用PCR检测技术鉴定柑桔黄龙病.结果表明:1、3、4、5、6号迟熟蕉柑单株不带碎叶病、衰退病、裂皮病和黄龙病,可用作繁殖无病毒苗木的备选材料.%Buds from grown trees in field were used as cions of shoot-tip grafting.,and 7 seedlings were obtained by the shoot-tip grafting technique. Rusk citrange, Mexican lime and Citron 861-S-1 were used as indicator plants to identify Citrus Tatter Leaf Virus (CTLV), Citrus Tristeza Virus (CTV) and Citrus Exocortis Viroid (CEVd), respectively, and PCR technique was used to detecting Citrus Huanglongbing (HLB) on the 7 seedlings. The results were following: no pathogen of CTLV, CTV, CEVd and HLB could be fund from number 1, 3, 4, 5, 6 seedlings of Late-ripening Jiaogan , and can be used for virus-free seedling propagation .

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

    Science.gov (United States)

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

    2012-01-01

    '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 β-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.

  13. Screening, identification of antagonistic yeast and its biocontrol efficacy against green mold caused by Penicillium digitotum of citrus fruit%柑橘采后绿霉病生防酵母菌的筛选、鉴定及其生防效果研究

    Institute of Scientific and Technical Information of China (English)

    耿鹏; 张彦博; 胡美英; 陈少华; 瞿菲

    2011-01-01

    [Objective]The study focused on isolating and characterizing yeast with abilities to control diseases of citrus fruits, to provide an alternative strategy to control postharvest disease of citrus fruits.[Method]An antagonistic yeast HP-10 was preliminarily identified as Kluyveromyces marsianus based on physiological-biochemical characteristics and the similarity analysis of its 18S rDNA sequence.The efficacy of HP-10 to Penicilluium digitatum in vitro and in vivo was studied by PDB trials and wounding inoculation.[Result]The spore germination of P.digitatum was significantly inhibited by the yeast cell suspensions in the tests on potato dextrose broth (PDB).High efficacy was achieved when fruits were treated with suspension of HP-10 at l08 CFU/mL.Disease incidence was reduced by 84.45% compared with control after 2 days incubation.When antagonistic yeat K.marxianus was treated at a concentration of 108 CFU/mL under 25 ℃ for 2 days,the decay incidence occured by 6.67% and lesion diameter 2.14 mm,while the conrol fruits had 93.33% disease incidence and 53.31 mm lesion diameter.[Conclusion]It was suggested that HP-10 had a great potential to control green mold of citrus fruit,and can be used as a new strategy for the biocontrol of postharvest diseases.%[目的]筛选能有效防治柑橘采后绿霉病菌(Penicillium digitatum)的拮抗酵母菌,为柑橘的采后保鲜提供参考.[方法]从园艺果园采集不同的水果样品,用稀释平板法分离筛选生防酵母菌株,并进行鉴定;采用PDB液体培养试验和刺伤接种的方法,研究不同浓度酵母菌悬浮液对离体和活体柑橘绿霉病菌的防治效果.[结果]获得1株拮抗酵母菌HP-10,结合生理生化特性及18S rDNA序列同源性分析,将其鉴定为马克斯克鲁维酵母(Kluyveromyces marxianus).离体和活体抑菌试验表明,菌株HP-10悬浮液能有效抑制绿霉病菌孢子的萌发;用108 CFU/mL HP-10悬浮液处理病原菌孢子时,其萌发率仅为3

  14. PROPOLIS EXTRACT IN POSTHARVEST CONSERVATION BANANA ' PRATA'

    Directory of Open Access Journals (Sweden)

    FLÁVIA REGINA PASSOS

    2016-01-01

    Full Text Available ABSTRACT In the present work were evaluated the effects of propolis coatings of various botanical sources on quality traits of bananas cv. Prata (Musa sapientum L. stored at room temperature. ´Prata´ bananas were selected and submitted to five postharvest treatments: four coatings applied by immersion in propolis extracts at a concentration of 2.5% (w/v and a control (without coating. Propolis extracts were applied as 1 a wild type aqueous propolis extract, 2 a wild type hydroalcoholic propolis extract, 3 a rosemary green type hydroalcoholic propolis extract and 4 a red type hydroalcoholic propolis extract. The bananas were evaluated at three-day intervals along 12 days for fresh weight losses, flesh firmness, soluble solids (SS, titratable acidity (TA, the ratio SS/TA and pH. Sensory analyses were performed after three and six days of storage by 55 not trained panelists designed for acceptability. At the end of the twelve-day storage period, bananas coated either with the rosemary green hydroalcoholic extract or with the aqueous extract presented lower fresh weight losses in comparison to the bananas of the control treatment. No differences were determined in relation to flesh firmness and along the storage period TA values decreased and pH values increased in bananas of all treatments. SS contents increased towards the end of the storage period that, consequently, contributed to increases in the SS/TA ratio. The most significant increase in SS/TA ratio was determined in bananas coated with the red type hydroalcoholic extract. Taste panelists did not detect significant differences amongst coated and not coated cv. Prata bananas up to six days of storage.

  15. How Does Host Carbon Concentration Modulate the Lifestyle of Postharvest Pathogens during Colonization?

    Science.gov (United States)

    Prusky, Dov B.; Bi, Fangcheng; Moral, Juan; Barad, Shiri

    2016-01-01

    Postharvest pathogens can penetrate fruit by breaching the cuticle or directly through wounds, and they show disease symptoms only long after infection. During ripening and senescence, the fruit undergo physiological processes accompanied by a decline in antifungal compounds, which allows the pathogen to activate a mechanism of secretion of small effector molecules that modulate host environmental pH. These result in the activation of genes under their optimal pH conditions, enabling the fungus to use a specific group of pathogenicity factors at each particular pH. New research suggests that carbon availability in the environment is a key factor triggering the production and secretion of small pH-modulating molecules: ammonia and organic acids. Ammonia is secreted under limited carbon and gluconic acid under excess carbon. This mini review describes our most recent knowledge of the mechanism of activation of pH-secreted molecules and their contribution to colonization by postharvest pathogens to facilitate the transition from quiescence to necrotrophic lifestyle. PMID:27635125

  16. Control of postharvest pathogens and colonization of the apple surface by antagonistic microorganisms in the field.

    Science.gov (United States)

    Leibinger, W; Breuker, B; Hahn, M; Mendgen, K

    1997-11-01

    ABSTRACT Selected isolates of Aureobasidium pullulans, Rhodotorula glutinis, and Bacillus subtilis reduced the size and number of lesions on wounded apples caused by the postharvest pathogens Penicillium expansum, Botrytis cinerea, and Pezicula malicorticis. Combinations of the antagonistic microorganisms were applied to apple trees in the field late in the growing season of two consecutive years. The population dynamics of the introduced microorganisms and the incidence of fruit decay were determined. Population sizes of introduced antagonists on apple surfaces increased in the field following application of treatments until harvest. After transfer of the fruit from the field into cold storage, the populations of the introduced antagonists remained higher than in the control treatments. Identification of the applied isolates of A. pullulans and R. glutinis during the experiments was achieved by isolate-specific DNA probes generated from random amplified polymorphic DNA. A combination of two strains of A. pullulans and one strain of R. glutinis suppressed rotting of apple to the same extent as the commonly used fungicide Euparen. Our data demonstrate that the application of antagonistic microorganisms in the field represents a promising alternative to fungicide treatments to control post-harvest diseases of apple.

  17. How Does Host Carbon Concentration Modulate the Lifestyle of Postharvest Pathogens during Colonization?

    Directory of Open Access Journals (Sweden)

    Dov B. Prusky

    2016-09-01

    Full Text Available Postharvest pathogens can penetrate fruit by breaching the cuticle or directly through wounds, remain quiescent and they show disease symptoms only long after infection. During ripening and senescence, the fruit undergo physiological processes accompanied by a decline in antifungal compounds, which allows the pathogen to activate a mechanism of secretion of small effector molecules that modulate host environmental pH. This results in the transcript activation of fungal genes under their optimal pH conditions, enabling the fungus to use a specific group of pathogenicity factors at each particular pH. New research suggests that carbon availability in the environment of the activating pathogen is a key factor triggering the production and secretion of small pH-modulating molecules: ammonia and organic acid. Ammonia is secreted under limited carbon and gluconic acid under excess carbon. This mini review describes our most recent knowledge on the mechanism of activation of the biosynthesis and secretion of fungal molecules that modulate the host pH, and their contribution to the transition from quiescence to necrotrophic lifestyle by the postharvest pathogens.

  18. Postharvest response of oranges of ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Aharoni, Y.; Lattar, F.S.; Monselise, S.P.

    1969-01-01

    Since the effect of ethylene on the respiration rate of young unripe oranges has not yet been described, experiments were carried out to study the respiratory response of such fruits to ethylene. Oranges (Citrus sinensis (L.) Osbeck) of the Washington navel, Shamouti and Valencia varieties, growing on a sandy loam near Rehovot, Israel, were picked in June, July, September, December and January. Immediately after picking, they were weighed, placed in glass jars, and stored at 20/sup 0/. Each experiment comprised 12 jars, 4 for each variety. A constant stream (200 ml/min) of air containing 20 ppm of ethylene was run through the jars. The respiration rate was measured by the amount of CO/sub 2/ evolved by the fruits, and based on a fresh weight unit. The results show that in all 3 varieties, ethylene caused an immediate rise in respiration rate, at all stages of development tested, regardless of whether it was applied from the beginning of the test or after a certain period of storage in air. The pattern of response to ethylene of young unripe oranges (picked in June, July, and September) was therefore similar to that of ripe ones (picked in December and January).

  19. Óleos essenciais no controle pós-colheita de Colletotrichum gloeosporioides em mamão Essential oils on postharvest control of Colletotrichum gloeosporioides in papaya fruit

    Directory of Open Access Journals (Sweden)

    P.R. Carnelossi

    2009-01-01

    Full Text Available Os subprodutos de plantas medicinais têm sido estudados como uma alternativa para o controle de doenças de plantas visando amenizar e/ou reduzir o uso abusivo de agrotóxicos, principalmente em condições pós-colheita. Assim, este trabalho teve como objetivo avaliar, in vitro e in vivo, o controle de Colletotrichum gloeosporioides, agente causal da antracnose do mamão em pós-colheita, por óleos essenciais (OEs de Cymbopogon citratus, Eucalyptus citriodora, Mentha arvensis e Artemisia dracunculus. Para inibição do crescimento micelial in vitro, os OEs foram incorporados ao BDA (Batata-dextrose-ágar tendo-se observado a inibição total ou parcial do crescimento micelial e da esporulação deste fitopatógeno, dependendo do óleo essencial utilizado. No ensaio in vivo utilizaram-se os OEs de C. citratus (1% e E. citriodora (1%. A inoculação com o fitopatógeno foi concomitante e 24 h após os tratamentos alternativos, que foram: óleos essenciais de C. citratus e de E. citriodora (1% e biomassa cítrica (150 mL 100 L-1 (Ecolife®. Os parâmetros avaliados foram severidade da doença, redução da massa, diâmetro, comprimento final dos frutos, pH e a concentração de sólidos solúveis totais (ºBrix. Pode-se observar que, no controle da doença, os frutos tratados e imediatamente inoculados com o fitopatógenos apresentaram maior AACPD (Área Abaixo da Curva do Progresso da Doença. Porém, frutos tratados e inoculados 24 h após os tratamentos apresentaram maior controle da doença, confirmando o potencial dos óleos essenciais testados no presente trabalho.The products from medicinal plants have been studied as an alternative in the control of plant diseases in order to mitigate and / or reduce pesticide abuse mainly in postharvest. Thus, the present study aimed to evaluate, in vitro and in vivo, the control of Colletotrichum gloeosporioides, the causative agent of papaya anthracnose, in postharvest using essential oils (EOs of

  20. Challenges and opportunities for the commercialization of postharvest biocontrol

    Science.gov (United States)

    The past twenty years has seen the field of postharvest biocontrol evolve into a sophisticated science with global research programs worldwide, numerous yearly publications, patented technologies, and the development of new commercial products. The use of these products, however, still remains limi...

  1. Sugarcane postharvest residue management in a temperate climate

    Science.gov (United States)

    Full retention of sugarcane (interspecific hybrids of Saccharum spp.) post-harvest residue often reduces subsequent ratoon crop yields in Louisiana. Experiments were conducted to determine the effects of different removal methods and removal timings on sugarcane growth and yield and to determine if...

  2. Postharvest quality of cut roses following electron-beam irradiation

    International Nuclear Information System (INIS)

    Cut Rosa x hybrida L. 'Royalty' flowers were used to determine the efficacy of electron-beam irradiation for increasing postharvest quality and decreasing petal infection by Botrytis cinerea Pers. In an experiment for determining the injury threshold, roses received electron-beam irradiation of 0, 0.5, 1, 2, and 4 kGy. Irradiation dosages greater than or equal to 4 kGy caused necrosis on petal tissue and decreased postharvest life at 20 degrees C. In a second experiment to evaluate postharvest quality, roses were irradiated at 0, 0.25, 0.5, 0.75, and 1 kGy. Dosages of 0.25 and 0.5 kGy slowed the rate of flower bud opening for 2 days but did not decrease postharvest quality when compared with nonirradiated roses. Roses that received irradiation dosages of 0.75 and 1 kGy showed unacceptable quality. In a third experiment, roses that had or had not been inoculated with B. cinerea were irradiated at 0, 0.25, 0.5, and 0.75 kGy. Irradiation did not control B. cinerea populations, and rose quality decreased as dosage increased. In a fourth experiment to determine the effect of irradiation on B. cinerea, conidia on water-agar plates exposed to dosages less than or equal to 1, 2, and 4 kGy germinated at rates of approximately 90%, 33%, and 2%, respectively, within 24 h

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

    Science.gov (United States)

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

    1991-10-01

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

  4. Clues into the metagenome of huanglongbing infected citrus by analysis of ancillary sequences from Ion Torrent whole genome Candidatus Liberibacter asiaticus sequencing

    Science.gov (United States)

    Huanglongbing (HLB) is a globally devastating disease of citrus. Presently, three etiological agents are associated with HLB and include; Candidatus Liberibacter asiaticus (CLas), Candidatus Liberibacter americanus; and Candidatus Liberibacter africanus. Attempts to determine alternate (non-Liberi...

  5. Determinants of Yam Postharvest Management in the Zabzugu District of Northern Ghana

    Directory of Open Access Journals (Sweden)

    Isaac Gershon Kodwo Ansah

    2016-01-01

    Full Text Available Postharvest loss reduction has received attention in many policy documents across nations to ensure global food security, particularly in developing countries. Many researchers have examined various options for reducing postharvest losses. We contribute our quota to this scientific discourse by using a different approach. We argue that the human element of managing postharvest loss is central and therefore poses the question of what are the characteristics of the farmer who manages postharvest losses better. We examine this question by using a cross section of yam farmers in the Zabzugu district in Northern Ghana and generate a proportional variable called postharvest management, which measures how effective a farmer works to reduce storage losses. We then use a fractional logistic regression model to examine the determinants of postharvest management. A significant result is that subsistence farmers manage postharvest losses better than commercial farmers. Characteristically, the farmer who effectively manages postharvest losses is a young, subsistence farmer, living in or close to a district capital with fewer household members, has attained formal education, and produces more yam. Efforts to reduce postharvest losses require the provision of access roads to remote towns or providing effective storage techniques and training on postharvest management practices.

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

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

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

  7. Signaling pathways in a Citrus EST database

    Directory of Open Access Journals (Sweden)

    Angela Mehta

    2007-01-01

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

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

    OpenAIRE

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

    2006-01-01

    Experiments were carried out with citrus (Citrus reticulate) and tea (Podocarpus fleuryi Hickel.) to 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...

  9. Description of the airflow produced by an air-assisted sprayer during pesticide applications to citrus

    Directory of Open Access Journals (Sweden)

    Ramon Salcedo

    2015-06-01

    Full Text Available Atmospheric drift of plant protection products is considered a major source of air pollution during pesticide applications. Citrus protection against pests and diseases usually requires application of these products using air-blast sprayers. Many authors have emphasized the influence of vegetation on the risk of spray drift. The aim of this work was to describe in detail how the airflow from an air-blast sprayer behaves when it reaches citrus trees and, in particular, the effect that the tree canopy has on this flow. Tests were conducted at a commercial citrus orchard with conventional machinery, placed parallel to a row of trees. Air velocity and direction was measured using a 3D ultrasonic anemometer in 225 points situated in three parallel planes perpendicular to the equipment. The stability of the airflow at each measuring point was studied and the mean velocities were graphically represented. Two vortexes, one behind the canopy, and another over the tree, have been deducted and never been reported before. Both may have an important influence on the trajectories of the sprayed droplets and, as a consequence, on the way in which plant protection products are diffused into the atmosphere. Observed turbulence intensities were higher than in similar experiments conducted in other tree crops, which may be attributable to the higher air volume generated by the machinery used for citrus protection and to the higher foliage density of citrus orchards.

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

    OpenAIRE

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

    2006-01-01

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

  11. Evaluating Sustainable Competitive Advantages in Brazilian and U.S. Processed Citrus Supply Chains: An Application of Porter’s Diamond Framework

    OpenAIRE

    Sterns, James A.; Thomas H. Spreen

    2010-01-01

    The processed citrus industries of Sao Paulo, Brazil and Florida, United States collectively account for over 80 percent of world orange juice production. In recent years, both industries have been confronted with serious plant disease outbreaks. Porter’s Diamond framework is used to assess the strenghts and weakness of the processed citrus industry in each country to confront the combined challenge of effectively combating these diseases while maintaining market competitiveness. Althou...

  12. Multilocus microsatellite analysis of ‘Candidatus Liberibacter asiaticus’ associated with citrus Huanglongbing worldwide

    Science.gov (United States)

    Huanglongbing (HLB) is one of the most destructive citrus diseases worldwide. In the United States (US), HLB is typically associated with the presence of a fastidious phloem-limited bacterium named ‘Candidatus Liberibacter asiaticus’, though other Liberibacter species also have been associated with ...

  13. Fractionation of the secondary metabolites of orange (Citrus sinensis L.) leaves by fast centrifugal partition chromatography

    Science.gov (United States)

    There is interest in the detection of changes in secondary metabolites in orange leaves in response to citrus greening disease. Conventional HPLC analysis readily provides detection of major phenolic compounds, but further, more detailed chromatographic analyses show many more compounds, to an exten...

  14. Development of rapid, sensitive and non-radioactive tissue-blot diagnostic method for the detection of citrus greening.

    Science.gov (United States)

    Nageswara-Rao, Madhugiri; Miyata, Shin-Ichi; Ghosh, Dilip; Irey, Mike; Garnsey, Stephen M; Gowda, Siddarame

    2013-01-01

    Citrus huanglongbing (HLB or citrus greening) is one of the most devastating diseases of citrus worldwide. The disease is caused by Gram-negative, phloem-limited α-proteobacterium, 'Candidatus Liberibacter asiaticus', vectored by the psyllid, Diaphorina citri Kuwayama. Citrus plants infected by the HLB bacterium may not show visible symptoms sometimes for years following infection and non-uniform distribution within the tree makes the detection of the pathogen very difficult. Efficient management of HLB disease requires rapid and sensitive detection early in the infection followed by eradication of the source of pathogen and the vector. The polymerase chain reaction (PCR) based method is most commonly employed for screening the infected/suspected HLB plants and psyllids. This is time consuming, cumbersome and not practical for screening large number of samples in the field. To overcome this, we developed a simple, sensitive, non-radioactive, tissue-blot diagnostic method for early detection and screening of HLB disease. Digoxigenin labeled molecular probes specific to 'Ca. L. asiaticus' nucleotide sequences have been developed and used for the detection of the pathogen of the HLB disease. The copy number of the target genes was also assessed using real-time PCR experiments and the optimized real-time PCR protocol allowed positive 'Ca. L. asiaticus' detection in citrus samples infected with 'Ca. L. asiaticus' bacterium.

  15. Characterization of the Asian Citrus Psyllid Transcriptome.

    Science.gov (United States)

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

    2014-01-01

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

  16. Characterization of the Asian Citrus Psyllid Transcriptome.

    Science.gov (United States)

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

    2014-01-01

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

  17. An in silico analysis of the key genes involved in flavonoid biosynthesis in Citrus sinensis

    Directory of Open Access Journals (Sweden)

    Adriano R. Lucheta

    2007-01-01

    Full Text Available Citrus species are known by their high content of phenolic compounds, including a wide range of flavonoids. In plants, these compounds are involved in protection against biotic and abiotic stresses, cell structure, UV protection, attraction of pollinators and seed dispersal. In humans, flavonoid consumption has been related to increasing overall health and fighting some important diseases. The goals of this study were to identify expressed sequence tags (EST in Citrus sinensis (L. Osbeck corresponding to genes involved in general phenylpropanoid biosynthesis and the key genes involved in the main flavonoids pathways (flavanones, flavones, flavonols, leucoanthocyanidins, anthocyanins and isoflavonoids. A thorough analysis of all related putative genes from the Citrus EST (CitEST database revealed several interesting aspects associated to these pathways and brought novel information with promising usefulness for both basic and biotechnological applications.

  18. Green Synthesis and Biological Activities of Gold Nanoparticles Functionalized with Citrus reticulata, Citrus aurantium, Citrus sinensis and Citrus grandis

    International Nuclear Information System (INIS)

    In the present study, gold nanoparticles (GNPs) were prepared at boiling temperature (90-95 degree C) by treating gold ions with Citrus fruit extracts. The effect of mixing ratios of the reactants and concentration of gold hydrochloride was studied. In the standardization process, 10/sup -3/ M solution of HAuCl/sub 4/.3H/sub 2/O was reacted with fruit extracts for half an hour at 90-95 degree C in different ratios. GNPs were characterized by UV-Vis spectroscopy (UV-Vis) and atomic force microscopy (AFM). Their stability was evaluated against varying pH solutions and volumes of sodium chloride along with metals and antibiotics sensing ability. The gold nanoparticles were tested for antibacterial and antifungal activities against various pathogenic strains. The UV-Vis spectra of gold nanoparticles gave surface plasmon resonance at about 540 nm while the AFM images revealed the particle size within the range of 70-100 nm. GNPs showed remarkable stability in varying pH solutions and salt volumes as well as high detection ability towards cobalt, copper, ceftriaxone and penicillin. Moreover, the GNPs possessed moderate antibacterial and good antifungal activity. These results concluded that the Citrus fruit extracts can be utilized for large scale synthesis of cost-effective nanoparticles which may have compatibility for biomedical and pharmaceutical applications. (author)

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

    OpenAIRE

    Hebert Adrianto; Subagyo Yotopranoto; Hamidah

    2014-01-01

    The used of chemicals as larvicidal may causing resistance, health problem, and environment problem. Leaf extracts of Citrus as biolarvicidal against Aedes aegypti larvae can be used as an alternative larvicidal. The aims of this study is to find out the species of Citrus in the study sample, which is the most effective as biolarvicidal. This study was conducted using nested experiment design, with six treatments and five replicates. Larvae mortality was observed after 24 and 48 hours. Then, ...

  20. Measuring the amount of vitamin C in citrus fruits by atwo step oxidation-

    Directory of Open Access Journals (Sweden)

    M.A. Ebrahimzadeh

    2005-01-01

    Full Text Available Background and purpose:Epidemiological evidence has suggested that consumption of fruits reduces the risk of chronic diseases such as cancer and cardiovascular disease. These benefits are often attributed to their high antioxidant components such as vitamin C (ascorbic acid. Citrus species are extremely rich sources for this vitamin, therefore we decided to determine the amount of vitamin C in some citrus fruits.Materials and methods : 13 species of commonly used citrus fruits were collected at the ripening stage. All the trees were cultivated in the experimental fields, Fajr citrus experimental institute. The vitamin C contents in fresh juice were determined by a two step oxidation-reduction titration. Data were analyzed using one-way analysis of variance (ANOVA followed by tukey, multiple range test.Results : Mean ascorbic acid contents of commonly used citrus were 85.4±18.3 mg/100 of juice (ranging from 57.9 to 131.6. The highest amount of vitamin C were found in Shahsavari orange 131.6 ± 4.2 and Sanguinello 100.7 ± 2.2 and the lowest amounts were in Tangelo 57.9 ± 2.3 and Unshiu 70.2 ± 2.2 mg/100 of juice. There was no correlation between Ascorbic acid contents and amount of citric acid in juice.Conclusion : Significant differences were found in vitamin C contents of citrus fruits. In order to increase the intake of vitamin C in daily diet, consuming fruits with higher contents of vitamin C is recommended.

  1. Influence of postharvest hot water treatment on nutritional and functional properties of kumquat (Fortunella japonica Lour. Swingle Cv. Ovale) fruit.

    Science.gov (United States)

    Schirra, Mario; Palma, Amedeo; D'Aquino, Salvatore; Angioni, Alberto; Minello, Elisabeth V; Melis, Marinella; Cabras, Paolo

    2008-01-23

    The present study investigated the influence of a hot water dip (HWD) for 2 min at 50 degrees C, a standard and effective treatment for postharvest decay control of citrus fruit, on the nutritional and health-related properties of kumquats. The results show that most of the parameters examined, including titratable acidity, soluble solids content, maturity index, glucose, fructose, sucrose, ascorbic acid, dehydroascorbic acid, alpha- and gamma-tocopherols, beta-carotene, zeaxantin, rhoifolin, and antioxidant activity, were not significantly affected by treatment. The levels of beta-cryptoxanthin, narirutin, and total flavonoids increased after HWD, whereas lutein and total phenols decreased. The concentration of the essential oil and the relative percentage of the individual components of the essential oil were not affected by HWD except for the minor compound p-menta-1,5-dien-1-ol, which increased after HWD. After storage, lower levels of glucose, total sugars, beta-carotene, beta-cryptoxanthin and lutein were recorded in HWD fruit. A decrease in antioxidant activity and increases in alpha-tocopherol and total vitamin E were found both in control and HWD fruit. The influence of HWD at 50 degrees C for 2 min on individual nutraceuticals and health-related properties was thus generally low and may depend on storage conditions.

  2. 2004 SWFWMD Citrus County Lidar Survey

    Data.gov (United States)

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

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

  6. The aconitate hydratase family from Citrus

    Directory of Open Access Journals (Sweden)

    Cercos Manuel

    2010-10-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

  8. Characterization of the Asian Citrus Psyllid Transcriptome

    OpenAIRE

    Reese, Justin; Christenson, Matthew K.; Leng, Nan; Saha, Surya; Cantarel, Brandi; Lindeberg, Magdalen; Tamborindeguy, Cecilia; MacCarthy, Justin; Weaver, Daniel; Trease, Andrew J.; Ready, Steven V.; Davis, Vincent M.; McCormick, Courtney; Haudenschild, Christian; Han, Shunsheng

    2014-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a vector for the causative agents of Huanglongbing, which threatens citrus production worldwide. This study reports and discusses the first D. citri transcriptomes, encompassing the three main life stages of D. citri, egg, nymph and adult. The transcriptomes were annotated using Gene Ontology (GO) and insecticide-related genes within each life stage were identified to aid the development of future D. citri insectici...

  9. Evaluation of natural colorants and their application on citrus fruit as alternatives to citrus red II

    Science.gov (United States)

    The poor peel color of some varieties of oranges and the hybrids, especially for early season fruits, is caused by the subtropical climate of Florida, and has resulted in the use of a red dye on the peel to improve fruit appearance and marketability. Citrus Red II (CR2), the commercial citrus color ...

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

    Institute of Scientific and Technical Information of China (English)

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

    2010-01-01

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

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

    NARCIS (Netherlands)

    Brussel, van E.W.

    1975-01-01

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

  12. 78 FR 41259 - Importation of Fresh Citrus Fruit From Uruguay, Including Citrus

    Science.gov (United States)

    2013-07-10

    ... (78 FR 8435-8441, Docket No. APHIS-2011-0060) a proposal \\1\\ to amend the regulations concerning the... Inspection Service 7 CFR Part 319 RIN 0579-AD59 Importation of Fresh Citrus Fruit From Uruguay, Including... the Citrus-related genus Fortunella, from Uruguay into the continental United States. As a...

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

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    NARCIS (Netherlands)

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

    2009-01-01

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

  15. The effects of inter-crop cultivation Between rows of citrus crop on spreading of Guignardia citricarpa Ascospores and in the citrus black spot occurrence

    Directory of Open Access Journals (Sweden)

    José Antonio Miranda Bellotte

    2013-03-01

    Full Text Available This study highlighted the effect of planting coast-cross grass and forage peanut cv. Amarilis between rows of Natal oranges on spreading of Guignardia citricarpa ascospores and consequent citrus black spot control. Treatments evaluated were: 1- conventional cultivation, free of fungicides; 2- conventional cultivation, using protective fungicides; 3- inter-crop cultivation of coast-cross grass between rows of citrus crops and; 4- inter-cropping cultivation of forage peanut between the rows of citrus crops. Quest Volumetric Spore SystemTM traps were set in order to determine the number of ascospores released. A total of 33 inspections were conducted weekly, from the end of August until early September the following year. A diagrammatic scale was used to determine the severity of the disease as well as the percentage of fruits having a commercial standard. The coast-cross grass was more effective in reducing the number of ascospores produced, whose average statistics were lower than in the conventional treatments, free-fungicides. The inter-crop and conventional cultivation method coupled with fungicide treatment was more effective in reducing the severity of citrus black spot symptoms, and differs statistically from the fungicide-free control method. These methods also resulted in a higher percentage of fruits of a commercial standard, ranging from the 89% through the 91% percentile, and the cultivation, free of fungicides, fell within the 73%.

  16. The Composition, Antioxidant and Antibacterial Activities of Cold-Pressed and Distilled Essential Oils of Citrus paradisi and Citrus grandis (L. Osbeck

    Directory of Open Access Journals (Sweden)

    Ming-Chiu Ou

    2015-01-01

    Full Text Available The chemical composition and functional activities of cold-pressed and water distilled peel essential oils of Citrus paradisi (C. paradisi and Citrus grandis (L. Osbeck (C. grandis were investigated in present study. Yields of cold-pressed oils were much higher than those of distilled oils. Limonene was the primary ingredient of essential oils of C. paradisi (cold 92.83%; distilled 96.06% and C. grandis (cold 32.63%; distilled 55.74%. In addition, C. grandis oils obtained were rich in oxygenated or nitrogenated compounds which may be involved in reducing cardiovascular diseases or enhancing sleep effectiveness. The order of free radical scavenging activities of 4 citrus oils was distilled C. paradisi oil > cold-pressed C. paradisi oil > distilled C. grandis oil > cold-pressed C. grandis oil. Cold-pressed C. grandis oil exhibited the lowest activity in all antioxidative assays. The order of antimicrobial activities of 4 citrus oils was distilled C. grandis oil, cold-pressed C. paradisi oil > distilled C. paradisi oil > cold-pressed C. paradisi oil. Surprisingly, distilled C. grandis oil exhibited better antimicrobial activities than distilled C. paradisi oil, especially against Escherichia coli and Salmonella enterica subsp. The results also indicated that the antimicrobial activities of essential oils may not relate to their antioxidative activities.

  17. The Composition, Antioxidant and Antibacterial Activities of Cold-Pressed and Distilled Essential Oils of Citrus paradisi and Citrus grandis (L.) Osbeck

    Science.gov (United States)

    Ou, Ming-Chiu; Liu, Yi-Hsin; Sun, Yung-Wei; Chan, Chin-Feng

    2015-01-01

    The chemical composition and functional activities of cold-pressed and water distilled peel essential oils of Citrus paradisi (C. paradisi) and Citrus grandis (L.) Osbeck (C. grandis) were investigated in present study. Yields of cold-pressed oils were much higher than those of distilled oils. Limonene was the primary ingredient of essential oils of C. paradisi (cold 92.83%; distilled 96.06%) and C. grandis (cold 32.63%; distilled 55.74%). In addition, C. grandis oils obtained were rich in oxygenated or nitrogenated compounds which may be involved in reducing cardiovascular diseases or enhancing sleep effectiveness. The order of free radical scavenging activities of 4 citrus oils was distilled C. paradisi oil > cold-pressed C. paradisi oil > distilled C. grandis oil > cold-pressed C. grandis oil. Cold-pressed C. grandis oil exhibited the lowest activity in all antioxidative assays. The order of antimicrobial activities of 4 citrus oils was distilled C. grandis oil, cold-pressed C. paradisi oil > distilled C. paradisi oil > cold-pressed C. paradisi oil. Surprisingly, distilled C. grandis oil exhibited better antimicrobial activities than distilled C. paradisi oil, especially against Escherichia coli and Salmonella enterica subsp. The results also indicated that the antimicrobial activities of essential oils may not relate to their antioxidative activities. PMID:26681970

  18. Thermal control of some post-harvest rot pathogens of Irish potato (solanum tuberosum l.

    Directory of Open Access Journals (Sweden)

    Salami Olusola Abiodun

    2007-01-01

    Full Text Available Thermal control effect on the incidence of some post-harvest rot pathogens of Solanum tuberosum (potato was investigated in this study. Three cultivars of potato tuber whose local names are, Patiska, Mai Bawondoya and Nicola were used for the study. Five pathogenic fungi viz: Botryodiplodia theobromae, Fusarium redolens, Fusarium oxysporum, Penicillium sp. and Rhizopus oryzae associated with post harvest storage rot of root-tubers, were isolated from diseased potatoes. Among the three species of potatoes used in the study, Patiska was found most resistant followed by Mai Bawondoya, while Nicola was the least resistant. Increase in substrate (i.e. soluble starch or CMC concentration enhanced a proportional increase in mycelial growth and in the amount of extracellular enzymes produced. Some of these test pathogens were found to produce cell wall degrading enzymes (i.e. amylase and cellulase. Preferential utilization of carbohydrate sources was established in this study based on the growth of test pathogens. Growth on potato broth medium was highest followed by growth on Cocoyam and Sweet potato broth media and least on Cassava broth medium. Growth of the test pathogens on carbohydrate sources was found at variant. The use of hot water treatment at different temperatures was found to significantly reduce post-harvest fungal populations on the surface of root-tubers. The efficacy of blanching in hot water at 60˚C was significantly higher than that of blanching in hot water at other temperatures. The control method adopted in this study showed that the problems of potatoes’ rot disease in storage (especially by the peasant farmers can be eradicated by thermal treatments without reducing the quality of the Irish tuber.

  19. Potential of Cerbera odollam as a bio-fungicide for post-harvest pathogen Penicilium digitatum

    Science.gov (United States)

    Singh, Harbant; Yin-Chu, Sue; Al-Samarrai, Ghassan; Syarhabil, Muhammad

    2015-05-01

    Postharvest diseases due to fungal infection contribute to economic losses in agriculture industry during storage, transportation or in the market. Penicillium digitatum is one of the common pathogen responsible for the postharvest rot in fruits. This disease is currently being controlled by synthetic fungicides such as Guazatine and Imazalil. However, heavy use of fungicides has resulted in environmental pollution, such as residue in fruit that expose a significant risk to human health. Therefore, there is a strong need to develop alternatives to synthetic fungicide to raise customer confidence. In the current research, different concentrations (500 to 3000 ppm) of ethanol extract of Cerbera odollam or commonly known as Pong-pong were compared with Neem and the controls (Positive control/Guazatine; Negative control/DMSO) for the anti-fungicide activity in PDA media contained in 10 cm diameter Petri dishes, using a modification of Ruch and Worf's method. The toxicity (Lc50) of the C.odollam extract was determined by Brine-shrimp test (BST). The results of the research indicated that crude extraction from C.odollam showed the highest inhibition rate (93%) and smallest colony diameter (0.63 cm) at 3000 ppm in vitro compared with Neem (inhibition rate: 88%; colony diameter: 1.33 cm) and control (Positive control/Guazatine inhibition rate: 79%, colony diameter: 1.9 cm; Negative control/DMSO inhibition rate: 0%, colony diameter: 9.2 cm). C.odollam recorded Lc50 value of 5 µg/ml which is safe but to be used with caution (unsafe level: below 2 µg/ml). The above anti-microbial activity and toxicity value results indicate that C.odollam has a potential of being a future bio-fungicide that could be employed as an alternative to synthetic fungicide.

  20. Fighting HLB with Citrus tristeza virus (CTV): Heterogeneity in the genome ends of CTV is an important consideration

    Science.gov (United States)

    As California prepares for a potential showdown with Huanglongbing (HLB), contemporary disease control strategies that use low inputs, yet produce high value control, are needed to manage the disease. With biotechnology, Citrus tristeza virus (CTV) may be developed into a tool for protection or trea...

  1. Screening preharvest/postharvest strategies to prevent fruit rot decay.

    Science.gov (United States)

    Vorstermans, B; Creemers, P

    2007-01-01

    In fruit growing preharvest sprayings in the orchard are mainly applied to protect fruit from decaying. Next to multisite fungicides (captan, thiram, tolylfluanid) the most commonly used products recognized for the Belgium market are Bellis (pyraclostrobin & boscalid) and the combination of Topsin M (thiophanate-methyl) and Frugico (diethofencarb). In general the spraying schedule varies depending on weather conditions (infection risk), preharvest interval of available fungicides, fruitgrower and cultivar of pome fruit (apple/pear). Facing the climatological conditions before picking the residue loading on the fruit surface can differ enormously. Also wet (pre)grading is considered to decrease the product residue resulting to fruits which are less protected before entering the cold storage room. In this context a partially replacement of the preharvest treatments by one postharvest application could offer a reliable alternative to the PPP reduction program (Plant Protection Products) in the orchard. A standardized application method by dipping or drenching will cover the fruits homogenically resulting in a rationalized fungicide use compared to the preharvest sprayings in the orchard. For the Belgium market Philabuster (imazalil & pyrimethanil) is registered for postharvest treatments since for this product a proper solution for the waste water of postharvest uses was developed to protect surface waters (Funds technology). Philabuster provides an advanced mould control towards fruit rot pathogens Gloeosporium spp., Botrytis cinerea and Penicillium spp. In this context several trials were set up to evaluate the biological efficacy of Philabuster alone or in combination with preharvest sprayings in the orchard. In concrete different preharvest spraying schedules were applied in the last six weeks before harvest on apple and pear facing parameters as rational fungicide use, antifungal effectiveness and cost price. The purpose was to select the optimal combination in

  2. Effects of postharvest preparation on organophosphate insecticide residues in apples.

    Science.gov (United States)

    Rawn, Dorothea F K; Quade, Sue C; Sun, Wing-Fung; Smith, Mark; Fouquet, André; Bélanger, André

    2008-02-13

    Apples were sampled directly from orchard trees at 96, 45, and 21 days postapplication with one of three organophosphate insecticides (azinphos methyl, phosalone, or phosmet, respectively). Individual apples were prepared for analysis following one of three postharvest preparations: no preparation, rinsed with deionized water for 10-15 s, or rinsed and peeled. Azinphos methyl, phosalone, and phosmet concentrations ranged from below the level of detection to 5.26 ng/g, 94.7 to 5720 ng/g, and 0.011 to 663 ng/g in the apples that received no postharvest preparation, respectively. Although rinsed apples had lower maximum concentrations than observed in apples with no preparation, levels were not significantly lower. Concentrations of all three OP insecticides in apples that were rinsed followed by peeling, however, were much lower (below detection limits to 0.733 ng/g, azinphos methyl; 0.322-219 ng/g, phosalone; and below detection limits to 44.0 ng/g, phosmet) than observed in apples that had been rinsed alone. Rinsing and peeling of apples resulted in a 74.5-97.9% reduction in OP residues, while rinsing alone lowered mean concentrations by 13.5-28.7% relative to apples that received no postharvest preparation.

  3. Citrus nobiletin suppresses inducible nitric oxide synthase gene expression in interleukin-1β-treated hepatocytes

    Energy Technology Data Exchange (ETDEWEB)

    Yoshigai, Emi [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); Okuyama, Tetsuya [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); Okumura, Tadayoshi [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); Nishino, Hoyoku [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)

    2013-09-13

    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-κB. -- 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 1β (IL-1β), 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 κB (NF-κB) 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.

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

    Directory of Open Access Journals (Sweden)

    Chuanyu Yang

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

  5. Dietary citrus pulp reduces lipid oxidation in lamb meat

    OpenAIRE

    Inserra, L.; Priolo, A.; L. Biondi; Lanza, M.; Bognanno, M.; Gravador, R.; Luciano, G.

    2014-01-01

    This study investigated the effect of replacing cereal concentrateswith high levels of dried citrus pulp in the diet on lamb meat oxidative stability. Over 56 days, lambs were fed a barley-based concentrate (Control) or concentrates inwhich 24% and 35% dried citrus pulpwere included to partially replace barley (Citrus 24% and Citrus 35%, respectively). Meat was aged under vacuum for 4 days and subsequently stored aerobically at 4 °C. The Control diet increased the redness, yellowness and satu...

  6. Identification and Control Methods of the Main Diseases and Insect Pests of Citrus%柑橘几种主要病虫害的识别与防治

    Institute of Scientific and Technical Information of China (English)

    罗守进

    2014-01-01

    The symptom and occur-rence regularity of citrus Huanglongbing, anthracnose, scab, leaf miner, arrowhead scales and red mite were introduced. Then the integrated control methods were put forward, which contained measures of agricultural control, physical control, biological control, chemical control and so on.%介绍了柑橘黄龙病、炭疽病、疮痂病和柑橘潜叶蛾、矢尖蚧、全爪螨的危害症状、发生规律,并从农业防治、物理防治、生物防治和化学防治等方面总结了几种病虫害的综合防治方法。

  7. Evaluation of natural colorants and their application on citrus fruit

    Science.gov (United States)

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

  8. Characterizing the citrus variety Carrizo genome through 454 shotgun sequencing

    Science.gov (United States)

    Citrus production is of global importance both in economic impact and significance to nutrition. The number of natural citrus species appears extremely limited. The genome size is small (haploid approximately 367 Mb), arranged on 18 chromosomes. The citrus variety Carrizo, generated by a ‘Washingt...

  9. Thirty years of citrus tristeza virus observations in Peru

    Science.gov (United States)

    The Peruvian citrus industry was devastated by epidemics of Citrus tristeza virus (CTV) decline (CTV-D) on sour orange rootstock between 1950 and 1965 and CTV stem pitting (SP) between 1965 and 1985. CTV-SP debilitates citrus and fruit production regardless of rootstock. Control of CTV-SP by mild st...

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

    Science.gov (United States)

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

    2014-01-01

    Citrus huanglongbing (HLB), caused by three species of fastidious, phloem-limited 'Candidatus Liberibacter', is one of the most destructive diseases of citrus worldwide. To date, there is no established cure for this century-old and yet, newly emerging disease. As a potential control strategy for citrus HLB, 31 antibiotics were screened for effectiveness and phytotoxicity using the optimized graft-based screening system with 'Candidatus Liberibacter asiaticus' (Las)-infected citrus scions. Actidione and Oxytetracycline were the most phytotoxic to citrus with less than 10% of scions surviving and growing; therefore, this data was not used in additional analyses. Results of principal component (PCA) and hierarchical clustering analyses (HCA) demonstrated that 29 antibiotics were clustered into 3 groups: highly effective, partly effective, and not effective. In spite of different modes of actions, a number of antibiotics such as, Ampicillin, Carbenicillin, Penicillin, Cefalexin, Rifampicin and Sulfadimethoxine were all highly effective in eliminating or suppressing Candidatus Liberibacter asiaticus indicated by both the lowest Las infection rate and titers of the treated scions and inoculated rootstock. The non-effective group, including 11 antibiotics alone with three controls, such as Amikacin, Cinoxacin, Gentamicin, Kasugamycin, Lincomycin, Neomycin, Polymixin B and Tobramycin, did not eliminate or suppress Las in the tested concentrations, resulting in plants with increased titers of Las. The other 12 antibiotics partly eliminated or suppressed Las in the treated and graft-inoculated plants. The effective and non-phytotoxic antibiotics could be potential candidates for control of citrus HLB, either for the rescue of infected citrus germplasm or for restricted field application.

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

    Directory of Open Access Journals (Sweden)

    Muqing Zhang

    Full Text Available Citrus huanglongbing (HLB, caused by three species of fastidious, phloem-limited 'Candidatus Liberibacter', is one of the most destructive diseases of citrus worldwide. To date, there is no established cure for this century-old and yet, newly emerging disease. As a potential control strategy for citrus HLB, 31 antibiotics were screened for effectiveness and phytotoxicity using the optimized graft-based screening system with 'Candidatus Liberibacter asiaticus' (Las-infected citrus scions. Actidione and Oxytetracycline were the most phytotoxic to citrus with less than 10% of scions surviving and growing; therefore, this data was not used in additional analyses. Results of principal component (PCA and hierarchical clustering analyses (HCA demonstrated that 29 antibiotics were clustered into 3 groups: highly effective, partly effective, and not effective. In spite of different modes of actions, a number of antibiotics such as, Ampicillin, Carbenicillin, Penicillin, Cefalexin, Rifampicin and Sulfadimethoxine were all highly effective in eliminating or suppressing Candidatus Liberibacter asiaticus indicated by both the lowest Las infection rate and titers of the treated scions and inoculated rootstock. The non-effective group, including 11 antibiotics alone with three controls, such as Amikacin, Cinoxacin, Gentamicin, Kasugamycin, Lincomycin, Neomycin, Polymixin B and Tobramycin, did not eliminate or suppress Las in the tested concentrations, resulting in plants with increased titers of Las. The other 12 antibiotics partly eliminated or suppressed Las in the treated and graft-inoculated plants. The effective and non-phytotoxic antibiotics could be potential candidates for control of citrus HLB, either for the rescue of infected citrus germplasm or for restricted field application.

  12. Temperature studies with the Asian citrus psyllid, Diaphorina citri: cold hardiness and temperature thresholds for oviposition.

    Science.gov (United States)

    Hall, David G; Wenninger, Erik J; Hentz, Matthew G

    2011-01-01

    This study was conducted to obtain information on the cold hardiness of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), in Florida and to assess upper and lower temperature thresholds for oviposition. The psyllid is an important pest in citrus because it transmits the bacterial pathogens responsible for citrus greening disease, Huanglongbing, considered the most serious citrus disease worldwide. D. citri was first found in Florida during 1998, and the disease was discovered during 2005. Little was known regarding cold hardiness of D. citri, but Florida citrus is occasionally subjected to notable freeze events. Temperature and duration were each significant sources of variation in percent mortality of D. citri subjected to freeze events. Relatively large percentages of adults and nymphs survived after being exposed for several hours to temperatures as low as -5 to -6 °C. Relatively large percentages of eggs hatched after being exposed for several hours to temperatures as low as -8 °C. Research results indicated that adult D. citri become cold acclimated during the winter through exposure to cooler winter temperatures. There was no evidence that eggs became cold acclimated during winter. Cold acclimation in nymphs was not investigated. Research with adult D. citri from laboratory and greenhouse colonies revealed that mild to moderate freeze events were usually nonlethal to the D. citri irrespective of whether they were cold acclimated or not. Upper and lower temperature thresholds for oviposition were investigated because such information may be valuable in explaining the geographic distribution and potential spread of the pest from Florida as well as how cooler winter temperatures might limit population growth. The estimated lower and upper thresholds for oviposition were 16.0 and 41.6 °C, respectively; the estimated temperature of peak oviposition over a 48 h period was 29.6 °C.

  13. Effect of Cyantraniliprole, a Novel Insecticide, on the Inoculation of Candidatus Liberibacter Asiaticus Associated with Citrus Huanglongbing by the Asian Citrus Psyllid (Hemiptera: Liviidae).

    Science.gov (United States)

    Ammar, El-Desouky; Hall, David G; Alvarez, Juan M

    2015-04-01

    The Asian citrus psyllid (Diaphorina citri Kuwayama) is the principal vector of 'Candidatus Liberibacter asiaticus' (CLas) associated with huanglongbing (HLB), the most serious citrus disease worldwide. New control measures including pesticides are urgently needed to combat HLB, especially to protect young or newly planted citrus trees from CLas-inoculation by vector psyllids. Here, we tested CLas-inoculation by D. citri adults (CLas-exposed, reared on infected plants) by feeding them for 7 d on excised healthy citrus leaves with dry residues of cyantraniliprole (Exirel), a novel insecticide, in comparison with fenpropathrin (Danitol 2.4EC), an insecticide commonly used against D. citri. Fewer adults settled (putatively feeding or probing) on leaves treated with cyantraniliprole than those treated with fenpropathrin or water controls. Also, psyllid adults died at a slower rate on leaves treated with cyantraniliprole than those treated with fenpropathrin, although the final cumulative mortality did not differ between the two treatments. In quantitative real-time polymerase chain reaction tests, 59.0-65.3% of the CLas-exposed psyllid adults were proven to be CLas-positive. Inoculation rates of CLas (using 10 adults per leaf) into untreated healthy citrus leaves (47.5-85%) were significantly higher than rates into leaves treated with cyantraniliprole or fenpropathrin (2.5-12.5%). Reduced inoculation rates to leaves treated with cyantraniliprole probably occurred as a result of reduced feeding or probing by D. citri. The excised leaf assay method, which took only a few weeks compared with up to a year or longer using whole plants, can be an effective tool for testing the effect of new pesticides or other treatments in reducing CLas inoculation or transmission by psyllid vectors. PMID:26470150

  14. Effect of Cyantraniliprole, a Novel Insecticide, on the Inoculation of Candidatus Liberibacter Asiaticus Associated with Citrus Huanglongbing by the Asian Citrus Psyllid (Hemiptera: Liviidae).

    Science.gov (United States)

    Ammar, El-Desouky; Hall, David G; Alvarez, Juan M

    2015-04-01

    The Asian citrus psyllid (Diaphorina citri Kuwayama) is the principal vector of 'Candidatus Liberibacter asiaticus' (CLas) associated with huanglongbing (HLB), the most serious citrus disease worldwide. New control measures including pesticides are urgently needed to combat HLB, especially to protect young or newly planted citrus trees from CLas-inoculation by vector psyllids. Here, we tested CLas-inoculation by D. citri adults (CLas-exposed, reared on infected plants) by feeding them for 7 d on excised healthy citrus leaves with dry residues of cyantraniliprole (Exirel), a novel insecticide, in comparison with fenpropathrin (Danitol 2.4EC), an insecticide commonly used against D. citri. Fewer adults settled (putatively feeding or probing) on leaves treated with cyantraniliprole than those treated with fenpropathrin or water controls. Also, psyllid adults died at a slower rate on leaves treated with cyantraniliprole than those treated with fenpropathrin, although the final cumulative mortality did not differ between the two treatments. In quantitative real-time polymerase chain reaction tests, 59.0-65.3% of the CLas-exposed psyllid adults were proven to be CLas-positive. Inoculation rates of CLas (using 10 adults per leaf) into untreated healthy citrus leaves (47.5-85%) were significantly higher than rates into leaves treated with cyantraniliprole or fenpropathrin (2.5-12.5%). Reduced inoculation rates to leaves treated with cyantraniliprole probably occurred as a result of reduced feeding or probing by D. citri. The excised leaf assay method, which took only a few weeks compared with up to a year or longer using whole plants, can be an effective tool for testing the effect of new pesticides or other treatments in reducing CLas inoculation or transmission by psyllid vectors.

  15. Maturity and Postharvest Performance of US Early Pride Seedless Mandarins

    Science.gov (United States)

    This article describes efforts underway at the US Horticultural Laboratory, Ft. Pierce, FL to develop seedless versions of seedy, but otherwise high quality citrus scions. Two approaches for development of seedless scions are discussed: 1) irradiation which has resulted in the release of 'US Seedle...

  16. Clues into the metagenome of Huanglongbing infected Citrus by analysis of ancillary sequences from Ion Torrent whole genome Candidatus Liberibacter asiaticus sequencing

    OpenAIRE

    Morgan, J K; Shatters, R. G.; Stover, E; Duan, Y. P.; Moore, G. A.; Powell, C A; Jarra-Cavieres, A.; Clark, S

    2014-01-01

    Huanglongbing (HLB) is a globally devastating disease of citrus.  Presently, three etiological agents are associated with HLB and include; Candidatus Liberibacter asiaticus (CLas), Candidatus Liberibacter americanus; and Candidatus Liberibacter africanus.  Attempts to determine alternate (non-Liberibacter) associated etiological agents of HLB have been performed, namely by metagenomic analyses with HLB phenotypic citrus of phloem tissue isolated from bark [1] and whole leaf midribs [2].  Thes...

  17. Evidence of Recombinant Citrus tristezavirus Isolate Occurring in Acid Lime cv. Pant Lemon Orchard in Uttarakhand Terai Region of Northern Himalaya in India

    OpenAIRE

    Singh, Jaywant Kumar; Tarafdar, Avijit; Sharma, Susheel Kumar; Biswas, Kajal Kumar

    2012-01-01

    The present study for the first time describes biological and molecular characterization of Citrus tristeza virus (CTV) occurring in the Terai area of Uttarakhand State in Northern Himalaya region of India. Direct antigen coated-ELISA and reverse transcriptase-polymerase chain reaction (RT-PCR) detected the CTV infection in Acid lime cv. Pant lemon (Citrus aurantifolia) orchards of Pantnagar with an estimated disease incidence of 16.6–20.5 %. To know the biological and genetic properties, an ...

  18. Selection efficiency for raspberry postharvest shelf life affected by storage temperature and harvest season

    Science.gov (United States)

    Improved postharvest quality is an important goal for fresh-market raspberry breeding programs. To determine if warm or cold storage following harvest would better facilitate the breeding selection process for the assessment of postharvest decay and bleed, pesticide-free fruit from cultivars and bre...

  19. Extension of Small-Scale Postharvest Horticulture Technologies—A Model Training and Services Center

    Directory of Open Access Journals (Sweden)

    Lisa Kitinoja

    2015-07-01

    Full Text Available A pilot Postharvest Training and Services Center (PTSC was launched in October 2012 in Arusha, Tanzania as part of a United States Agency for International Development (USAID funded project. The five key components of the PTSC are (1 training of postharvest trainers, (2 postharvest training and demonstrations for local small-scale clientele, (3 adaptive research, (4 postharvest services, and (5 retail sales of postharvest tools and supplies. During the years of 2011–2012, a one year e-learning program was provided to 36 young horticultural professionals from seven Sub-Saharan African countries. These postharvest specialists went on to train more than 13,000 local farmers, extension workers, food processors, and marketers in their home countries in the year following completion of their course. Evaluators found that these specialists had trained an additional 9300 people by November 2014. When asked about adoption by their local trainees, 79% reported examples of their trainees using improved postharvest practices. From 2012–2013, the project supported 30 multi-day training programs, and the evaluation found that many of the improved practices being promoted were adopted by the trainees and led to increased earnings. Three PTSC components still require attention. Research activities initiated during the project are incomplete, and successful sales of postharvest goods and services will require commitment and improved partnering.

  20. Metabolomics analysis of postharvest ripening heterogeneity of ‘Hass' avocadoes

    NARCIS (Netherlands)

    Pedreschi, R.; Munoz, P.; Robledo, P.; Becerra, C.; Defilippi, B.G.; Eekelen, van H.D.L.M.; Mumm, R.; Westra, E.H.; Vos, de R.C.H.

    2014-01-01

    The complex physiology of ‘Hass’ avocado renders its postharvest ripening heterogeneous and unpre-dictable. Several approaches have previously been undertaken to broaden our understanding of the causesof this postharvest ripening heterogeneity but without much success. In this study, a fruit biopsy

  1. Biological control of toxigenic citrus and papaya-rotting fungi by Streptomyces violascens MT7 and its extracellular metabolites.

    Science.gov (United States)

    Choudhary, Bharti; Nagpure, Anand; Gupta, Rajinder K

    2015-12-01

    An Indian indigenous, Loktak Lake soil isolate Streptomyces violascens MT7 was assessed for its biocontrol potential both in vitro and in vivo against toxigenic fruit-rotting fungi. Strain MT7 exhibited broad-spectrum antifungal activity against various pathogenic postharvest fungi of citrus and papaya. In shake-flask fermentation, antagonist S. violascens MT7 highly produced extracellular antifungal metabolites in early stationary growth phase in glucose-yeast extract-malt extract (M93) broth. Both extracellular culture fluid (ECF) and its n-butanol extract showed significant broad-spectrum fungal mycelial inhibition of several tested fruit-rotting fungi. Antifungal metabolite was found to be heat stable, nonpeptidic, and polyene type antibiotic. The lowest minimum inhibitory concentration (MIC) of n-butanol extract against Colletotrichum gloeosporioides MTCC 9664 and Aspergillus niger MTCC 281 was 0.0312 and 0.0625 mg/ml, respectively. Purification of n-butanol extract through silica gel chromatography resulted in partial purification of bioactive metabolite and the TLC autobiography revealed the presence of single antifungal metabolite with Rf value of 0.755. In vivo bioassays demonstrated the biocontrol potential of tested biocontrol agents on fruit-rotting fungi. Use of cell suspension of S. violascens MT7, extracellular metabolite(s), and n-butanol extract significantly (p Citrus reticulata Blanco (oranges) and soft-rot development on papaya fruits. Therefore, these results strongly suggest a high potential for application of S. violascens MT7 and its extracellular metabolites as an effective eco-friendly alternative to synthetic fungicides for controlling toxigenic citrus and papaya-rotting fungi. PMID:26214840

  2. Evaluation of natural colorants and their application on citrus fruit as alternatives to Citrus Red No. 2

    Science.gov (United States)

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

  3. Efficacy of plant-derived pesticides in the control of myco-induced postharvest rots of tubers and agricultural products: A review

    Directory of Open Access Journals (Sweden)

    D. N. Enyiukwu

    2014-02-01

    Full Text Available The most important losses in agricultural production which involve the greatest costs on the farm economy occur postharvest. It is estimated that worldwide between 10 and 40% losses of agricultural produce occur postharvest. Losses are more severe in developing than developed nations of the world. Several species of fungi and in some cases bacteria participate in postharvest deterioration and rots of tubers and agro-produce. These include species of Aspergillus, Fusarium, Colletotrichum, Macrophomina, Penicillium and Rhizopus amongst several others. In a bid to control these storage diseases several control techniques including physical, biological, and chemical and in recent times plant-based pesticides are employed. Chemical control has been identified as the most popular and most effective means of controlling plant diseases. However, it is being de-emphasized due largely to mammalian toxicity occasioned by chemical residues in crops. This in addition to many other demerits on ecological health and build-up of pathogens’ resistance to some of the most effective fungicides have prompted search for alternatives. Recently in plant pathology many tropical plants are being screened for fungitoxic properties. This review presents highlights of the different control techniques and emphasized the efficacy of plant-based pesticides for control of myco-induced storage rots of tubers and agricultural products in the tropics.

  4. Salmonella surveillance and control at post-harvest in the Belgian pork meat chain.

    Science.gov (United States)

    Delhalle, L; Saegerman, C; Farnir, F; Korsak, N; Maes, D; Messens, W; De Sadeleer, L; De Zutter, L; Daube, G

    2009-05-01

    Salmonella remains the primary cause of reported bacterial food borne disease outbreaks in Belgium. Pork and pork products are recognized as one of the major sources of human salmonellosis. In contrast with the primary production and slaughterhouse phases of the pork meat production chain, only a few studies have focussed on the post-harvest stages. The goal of this study was to evaluate Salmonella and Escherichia coli contamination at the Belgian post-harvest stages. E. coli counts were estimated in order to evaluate the levels of faecal contamination. The results of bacteriological analysis from seven cutting plants, four meat-mincing plants and the four largest Belgian retailers were collected from official and self-monitoring controls. The prevalence of Salmonella in the cutting plants and meat-mincing plants ranged from 0% to 50%. The most frequently isolated serotype was Salmonella typhimurium. The prevalence in minced meat at retail level ranged from 0.3% to 4.3%. The levels of Salmonella contamination estimated from semi-quantitative analysis of data relating to carcasses, cuts of meat and minced meat were equal to -3.40+/-2.04 log CFU/cm(2), -2.64+/-1.76 log CFU/g and -2.35+/-1.09 log CFU/g, respectively. The E. coli results in meat cuts and minced meat ranged from 0.21+/-0.50 to 1.23+/-0.89 log CFU/g and from 1.33+/-0.58 to 2.78+/-0.43 log CFU/g, respectively. The results showed that faecal contamination still needs to be reduced, especially in specific individual plants. PMID:19269567

  5. Effects of Chitin and Its Derivative Chitosan on Postharvest Decay of Fruits: A Review

    Directory of Open Access Journals (Sweden)

    Weimin Liu

    2011-01-01

    Full Text Available Considerable economic losses to harvested fruits are caused by postharvest fungal decay during transportation and storage, which can be significantly controlled by synthetic fungicides. However, considering public concern over pesticide residues in food and the environment, there is a need for safer alternatives for the control of postharvest decay to substitute synthetic fungicides. As the second most abundant biopolymer renewable source in nature, chitin and its derivative chitosan are widely used in controlling postharvest decay of fruits. This review aims to introduce the effect of chitin and chitosan on postharvest decay in fruits and the possible modes of action involved. We found most of the actions discussed in these researches rest on physiological mechanisms. All of the mechanisms are summarized to lay the groundwork for further studies which should focus on the molecular mechanisms of chitin and chitosan in controlling postharvest decay of fruits.

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

    Science.gov (United States)

    Li, Jinyun; Wang, Nian

    2014-02-01

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

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

    Science.gov (United States)

    Li, Jinyun; Wang, Nian

    2014-02-01

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

  8. Past and future of a century old Citrus tristeza virus collectionA California citrus germplasm tale

    Directory of Open Access Journals (Sweden)

    Jinbo eWang

    2013-12-01

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

  9. Seed transmission of Candidatus Liberibacter asiaticus in periwinkle and dodder resulted in low bacterial titer and very mild disease in periwinkle

    Science.gov (United States)

    Canadidatus Liberibacter asiaticus (Las) is the most widely-distributed of three species of Liberibacter that are associated with citrus Huanglongbing (HLB), a lethal disease of citrus worldwide. In addition to citrus, periwinkle (Catharanthus roseus) and dodder (Cuscuta pentagona) are two experime...

  10. 海洋放线菌A3202的分离鉴定及其对柑橘采后病害的防效%Isolation and identification of marine actinomyces A3202 and its control efficacy against postharvest citrus diseases

    Institute of Scientific and Technical Information of China (English)

    鹿连明; 杜丹超; 程保平; 胡秀荣; 陈国庆

    2014-01-01

    为获得用于防治柑橘采后病害的海洋放线菌,以柑橘青霉病菌Penicillium italicum、柑橘绿霉病菌P.digitatum和柑橘炭疽病菌Colletotrichum gloeosporioides为指示菌,对分离到的25株海洋放线菌进行筛选.通过平板对峙法测定拮抗菌株的抑菌谱,并测定其发酵产物粗提物对柑橘果实采后病害的防效,根据形态特征、培养特征、生理生化特征及16S rDNA序列对其进行鉴定.结果表明,分离自鳞笠藤壶Tetraclita squamosa的菌株A3202对3种指示菌均具有强抑菌活性,对供试13种植物病原菌的菌丝生长具有不同程度的抑制作用,尤其对柑橘青霉病菌和柑橘绿霉病菌的抑制作用最强,抑菌带宽度分别可达2.33±0.05 cm和2.32±0.10cm.该菌株800 mg/L粗提物溶液对接种后7d的柑橘青霉病、柑橘绿霉病和柑橘炭疽病的相对防效均可达100%.初步鉴定该菌株为放线菌中的米修链霉菌Streptomyces misionensis.

  11. PCR detection of huanglongbing pathogen in different parts of citrus plants in the field and analysis of the cause of the disease%田间柑橘植株不同部位黄龙病菌的PCR检测及发病原因分析

    Institute of Scientific and Technical Information of China (English)

    鹿连明; 范国成; 胡秀荣; 张利平; 黄振东; 陈国庆

    2011-01-01

    [Objective]Understanding the distribution of pathogen in plants laid the foundation for further studies on its diffusion in plants, and clarifying the reason for disease occurrence could provide reference for effective control of the disease.[Method]Citrus huanglongbing in Taizhou, Zhejiang Province, was investigated, and the pathogen in different plants and different parts of the same plant, was detected by conventional and nested PCR.[Result]It showed that the pathogen was present in leaves with or without symptoms and in branches in one orchard, but not in surrounding plants.In the other orchards, the pathogen was present in leaves, branches, main trunk, rootstock, and also in surrounding plants with symptoms.[Conclusion]It indicated that the causes of the disease in the two plants were different.One might be infected by citrus psylla, while the other by grafting.%[目的]了解黄龙病菌在柑橘植株不同部位的分布,为深入研究病菌在植株体内的扩散情况莫定基础;明确病害的发生原因为有效防控该病害提供借鉴.[方法]调查浙江省台州市柑橘黄龙病(huanglongbing,HLB)的发生情况,通过常规和巢式PCR,检测了发病情形不同的两个果园内柑橘病株不同部位及不同植株中的黄龙病菌,并对其发病原因进行分析.[结果]发现一果园内病株的无症状叶片、有症状叶片和枝条中均含有黄龙病菌,而其周围植株不含病菌;另一果园内病株的有症状叶片、枝条、主干和砧木中均含有黄龙病菌,而其周围植株也含菌.[结论]分析认为这两种果园内柑橘植株发病原因不同,一种可能为通过携带黄龙病菌的柑橘木虱所感染,另一种可能为嫁接过程中通过带菌的接穗感染.

  12. Inhibitory effect of some spice essential oils on Penicillium digitatum causing postharvest rot in citrus

    OpenAIRE

    Akgül, Attila; Özcan, Musa; Yigit, Fahri

    2000-01-01

    In this study to control blue mould caused by Penicillium digitatum, essential oil of cumin was applied with filter paper discs of 6 mm diameter which were soaked in 0,04 ml oil and vapour effect inhibited completely mycelial growth and spore germination of pathogen in vitro. When filter paper discs soaked in essential oils of black thyme, dill, coriander and rosemary were placed on the culture medium (PDA), they had no effect on the mycelial growth. Their vapour effect inhibited mycelial gro...

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

    Science.gov (United States)

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

    2010-10-01

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

  14. Noninvasive maturity detection of citrus with machine vision

    Science.gov (United States)

    Ying, Yibin; Xu, Zhenggang; Fu, Xiaping; Liu, Yande

    2004-03-01

    A computer vision system was established to explore a method for citrus maturity detection. The surface color information and the ratio of total soluble solid to titratable acid (TSS/TA) were used as maturity indexes of citrus. The spectral reflectance properties with different color were measured by UV-240 ultraviolet and visible spectrophotometer. The biggest discrepancy of gray levels between citrus pixels and background pixels was in blue component image by image background segmentation. Dynamic threshold method for background segmentation had best result in blue component image. Methods for citrus image color description were studied. The citrus spectral reflectance experiments showed that green surface and saffron surface of citrus were of highest spectral reflectance at the wavelength of 700nm, the difference between them reached to maximum, about 53%, and the image acquired at this wavelength was of more color information for maturity detection. A triple-layer feed forward network was established to map citrus maturity from the hue frequency sequence by the mean of artificial neural network. After training, the network mapper was used to detect the maturity of the test sample set, which was composed of 252 Weizhang citrus with different maturity. The identification accuracy of mature citrus reached 79.1%, that of immature citrus was 63.6%, and the mean identification accuracy was 77.8%. This study suggested that it is feasible to detect citrus maturity non-invasively by using the computer vision system and hue frequency sequence method.

  15. Next generation haplotyping to decipher nuclear genomic interspecific admixture in Citrus species: analysis of chromosome 2

    OpenAIRE

    Curk, Franck; Ancillo, Gema; Garcia-Lor, Andres; Luro, François; Perrier, Xavier; Jacquemoud-Collet, Jean-Pierre; Navarro, Luis; Ollitrault, Patrick

    2014-01-01

    Background The most economically important Citrus species originated by natural interspecific hybridization between four ancestral taxa (Citrus reticulata, Citrus maxima, Citrus medica, and Citrus micrantha) and from limited subsequent interspecific recombination as a result of apomixis and vegetative propagation. Such reticulate evolution coupled with vegetative propagation results in mosaic genomes with large chromosome fragments from the basic taxa in frequent interspecific heterozygosity....

  16. Genome-wide identification of sweet orange (Citrus sinensis histone modification gene families and their expression analysis during the fruit development and fruit-blue mold infection process

    Directory of Open Access Journals (Sweden)

    Jidi eXu

    2015-08-01

    Full Text Available In eukaryotes, histone acetylation and methylation have been known to be involved in regulating diverse developmental processes and plant defense. These histone modification events are controlled by a series of histone modification gene families. To date, there is no study regarding genome-wide characterization of histone modification related genes in citrus species. Based on the two recent sequenced sweet orange genome databases, a total of 136 CsHMs (Citrus sinensis histone modification genes, including 47 CsHMTs (histone methyltransferase genes, 23 CsHDMs (histone demethylase genes, 50 CsHATs (histone acetyltransferase genes, and 16 CsHDACs (histone deacetylase genes were identified. These genes were categorized to 11 gene families. A comprehensive analysis of these 11 gene families was performed with chromosome locations, phylogenetic comparison, gene structures and conserved domain compositions of proteins. In order to gain an insight into the potential roles of these genes in citrus fruit development, 42 CsHMs with high mRNA abundance in fruit tissues were selected to further analyze their expression profiles at six stages of fruit development. Interestingly, a numbers of genes were expressed highly in flesh of ripening fruit and some of them showed the increasing expression levels along with the fruit development. Furthermore, we analyzed the expression patterns of all 136 CsHMs response to the infection of blue mold (Penicillium digitatum, which is the most devastating pathogen in citrus postharvest process. The results indicated that 20 of them showed the strong alterations of their expression levels during the fruit-pathogen infection. In conclusion, this study presents a comprehensive analysis of the histone modification gene families in sweet orange and further elucidates their behaviors during the fruit development and the blue mold infection responses.

  17. Genome-wide identification of sweet orange (Citrus sinensis) histone modification gene families and their expression analysis during the fruit development and fruit-blue mold infection process.

    Science.gov (United States)

    Xu, Jidi; Xu, Haidan; Liu, Yuanlong; Wang, Xia; Xu, Qiang; Deng, Xiuxin

    2015-01-01

    In eukaryotes, histone acetylation and methylation have been known to be involved in regulating diverse developmental processes and plant defense. These histone modification events are controlled by a series of histone modification gene families. To date, there is no study regarding genome-wide characterization of histone modification related genes in citrus species. Based on the two recent sequenced sweet orange genome databases, a total of 136 CsHMs (Citrus sinensis histone modification genes), including 47 CsHMTs (histone methyltransferase genes), 23 CsHDMs (histone demethylase genes), 50 CsHATs (histone acetyltransferase genes), and 16 CsHDACs (histone deacetylase genes) were identified. These genes were categorized to 11 gene families. A comprehensive analysis of these 11 gene families was performed with chromosome locations, phylogenetic comparison, gene structures, and conserved domain compositions of proteins. In order to gain an insight into the potential roles of these genes in citrus fruit development, 42 CsHMs with high mRNA abundance in fruit tissues were selected to further analyze their expression profiles at six stages of fruit development. Interestingly, a numbers of genes were expressed highly in flesh of ripening fruit and some of them showed the increasing expression levels along with the fruit development. Furthermore, we analyzed the expression patterns of all 136 CsHMs response to the infection of blue mold (Penicillium digitatum), which is the most devastating pathogen in citrus post-harvest process. The results indicated that 20 of them showed the strong alterations of their expression levels during the fruit-pathogen infection. In conclusion, this study presents a comprehensive analysis of the histone modification gene families in sweet orange and further elucidates their behaviors during the fruit development and the blue mold infection responses.

  18. Genome-wide identification of sweet orange (Citrus sinensis) histone modification gene families and their expression analysis during the fruit development and fruit-blue mold infection process.

    Science.gov (United States)

    Xu, Jidi; Xu, Haidan; Liu, Yuanlong; Wang, Xia; Xu, Qiang; Deng, Xiuxin

    2015-01-01

    In eukaryotes, histone acetylation and methylation have been known to be involved in regulating diverse developmental processes and plant defense. These histone modification events are controlled by a series of histone modification gene families. To date, there is no study regarding genome-wide characterization of histone modification related genes in citrus species. Based on the two recent sequenced sweet orange genome databases, a total of 136 CsHMs (Citrus sinensis histone modification genes), including 47 CsHMTs (histone methyltransferase genes), 23 CsHDMs (histone demethylase genes), 50 CsHATs (histone acetyltransferase genes), and 16 CsHDACs (histone deacetylase genes) were identified. These genes were categorized to 11 gene families. A comprehensive analysis of these 11 gene families was performed with chromosome locations, phylogenetic comparison, gene structures, and conserved domain compositions of proteins. In order to gain an insight into the potential roles of these genes in citrus fruit development, 42 CsHMs with high mRNA abundance in fruit tissues were selected to further analyze their expression profiles at six stages of fruit development. Interestingly, a numbers of genes were expressed highly in flesh of ripening fruit and some of them showed the increasing expression levels along with the fruit development. Furthermore, we analyzed the expression patterns of all 136 CsHMs response to the infection of blue mold (Penicillium digitatum), which is the most devastating pathogen in citrus post-harvest process. The results indicated that 20 of them showed the strong alterations of their expression levels during the fruit-pathogen infection. In conclusion, this study presents a comprehensive analysis of the histone modification gene families in sweet orange and further elucidates their behaviors during the fruit development and the blue mold infection responses. PMID:26300904

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

    Science.gov (United States)

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

    2014-08-01

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

  20. Odorants for surveillance and control of the Asian Citrus Psyllid (Diaphorina citri.

    Directory of Open Access Journals (Sweden)

    Iliano V Coutinho-Abreu

    Full Text Available BACKGROUND: The Asian Citrus Psyllid (ACP, Diaphorina citri, can transmit the bacterium Candidatus Liberibacter while feeding on citrus flush shoots. This bacterium causes Huanglongbing (HLB, a major disease of citrus cultivation worldwide necessitating the development of new tools for ACP surveillance and control. The olfactory system of ACP is sensitive to variety of odorants released by citrus plants and offers an opportunity to develop new attractants and repellents. RESULTS: In this study, we performed single-unit electrophysiology to identify odorants that are strong activators, inhibitors, and prolonged activators of ACP odorant receptor neurons (ORNs. We identified a suite of odorants that activated the ORNs with high specificity and sensitivity, which may be useful in eliciting behavior such as attraction. In separate experiments, we also identified odorants that evoked prolonged ORN responses and antagonistic odorants able to suppress neuronal responses to activators, both of which can be useful in lowering attraction to hosts. In field trials, we tested the electrophysiologically identified activating odorants and identified a 3-odor blend that enhances trap catches by ∼230%. CONCLUSION: These findings provide a set of odorants that can be used to develop affordable and safe odor-based surveillance and masking strategies for this dangerous pest insect.

  1. Phytophthora parasitica transcriptome, a new concept in the understanding of the citrus gummosis

    Directory of Open Access Journals (Sweden)

    Daniel D. Rosa

    2007-01-01

    Full Text Available Due to the economic importance of gummosis disease for the citriculture, studies on P. parasitica-Citrus interaction comprise a significant part in the Brazilian Citrus genome data bank (CitEST. Among them, two cDNA libraries constructed from two different growth conditions of the P. parasitica pathogen are included which has generated the PP/CitEST database (CitEST - Center APTA Citros Sylvio Moreira/IAC- Millennium Institute. Through this genomic approach and clustering analyses the following has been observed: out of a total of 13,285 available in the Phytophthora parasitica database, a group of 4,567 clusters was formed, comprising 2,649 singlets and 1,918 contigs. Out of a total of 4,567 possible genes, only 2,651 clusters were categorized; among them, only 4.3% shared sequence similarities with pathogenicity factors and defense. Some of these possible genes (103 corresponding to 421 ESTs, were characterized by phylogenetic analysis and discussed. A comparison made with the COGEME database has shown homology which may be part of an evolutionary pathogenicity pathway present in Phytophthora and also in other fungi. Many of the genes which were identified here, which may encode proteins associated to mechanisms of citrus gummosis pathogenicity, represent only one facet of the pathogen-host Phytophthora - Citrus interaction.

  2. Expression profile of oxidative and antioxidative stress enzymes based on ESTs approach of citrus

    Directory of Open Access Journals (Sweden)

    Luis Antonio Peroni

    2007-01-01

    Full Text Available Plants not only evolve but also reduce oxygen in photosynthesis. An inevitable consequence of this normal process is the production of reactive oxygen species (ROS. Plants are adequately protected by the presence of multiple antioxidative enzymes in the cytosol and also in the different cell organelles such as chloroplasts, mitochondria, and peroxisomes. Traditionally, ROS were considered to be only a toxic byproduct of aerobic metabolism. However, recently it has become apparent that plants actively produce these molecules which may control many different physiological processes such as abiotic and biotic stress response, pathogen defense and systemic signaling. The search results using the Citrus Genome Program in Brazil (CitEST for oxidative stress and the antioxidant enzyme system in Citrus Sinensis variety ‘Pera IAC’ indicated that the multiple ROS-scavenging enzymes were expressed throughout all citrus tissues. The analyses demonstrated the ubiquitous expression of metallothioneins, probably indicating a constitutive expression pattern. Oxalate oxidase has been identified as the most abundant expressed gene in developing fruits, which suggests a specific function in the ripening of citrus fruit. Moreover, infected leaves with Xylella fastidiosa and Leprosis citri showed a massive change in their ROS gene expression profile which may indicate that the suppression of ROS detoxifying mechanisms may be involved in the induction of the diseases.

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

    Science.gov (United States)

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

    2014-08-01

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

  4. Phytochemistry and biological activity of Spanish Citrus fruits.

    Science.gov (United States)

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

    2014-04-01

    The evaluation of the potential inhibitory activity on α-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 α-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

  5. Isolation of Xylella fastidiosa from Citrus sinensis (L) Osb. And Vitis vinifera and study of genetic diversity in Costa Rica

    International Nuclear Information System (INIS)

    Xylella fastidiosa is a plant pathogenic bacterium that causes diseases in different crops. Symptoms similar to those caused by citrus variegated chlorosis (CVC) were observed in sweet orange trees which served as shade and fences in coffee plantations in Costa Rica, in 2002. A total of 35 citrus trees and 24 vines from eight different districts and 3 respectively were evaluated by 'double antibody sandwich enzyme-linked immunosorbent assay' (DASELISA), resulting in 21 citrus and 19 positive vid. From four citrus trees and six of vines, were obtained six isolates and seven isolates respectively in solid medium, whose morphological and biochemical characteristics coincided with those reported in the literature as characteristic of X. fastidiosa. The identity of the isolates is confirmed by the chain polymerase reaction (PCR) using primers 272-1/272-2int and RST31/RST33. Three isolates from Grecia (Alajuela Province) amplified a band of 500pb using specific primers 272-2int/CVC-1 for strains of X. fastidiosa that cause CVC. The genetic variability of isolates from each other in comparison with isolates of coffee in Costa Rica, U.S. grapes and citrus in Brazil have been studied using techniques of random amplification polymorphism DNA (RAPD) and length polymorphisms of restriction fragments (RFLPs) of the products obtained with primers int/272-2int JB-1/JB-2 and 272-1. The results showed a clear separation between citrus isolates of Costa Rica; and, an association of three of them with the strains of citrus in Brasil. Also, an association between strains of coffee of Costa Rica with grape vines in the U.S. An association of molecular analysis confirmed the data variance. (author)

  6. Biogenic emissions from Citrus species in California

    Science.gov (United States)

    Fares, Silvano; Gentner, Drew R.; Park, Jeong-Hoo; Ormeno, Elena; Karlik, John; Goldstein, Allen H.

    2011-09-01

    Biogenic Volatile Organic Compounds (BVOC) emitted from plants are the dominant source of reduced carbon chemicals to the atmosphere and are important precursors to the photochemical production of ozone and secondary organic aerosols. Considering the extensive land used for agriculture, cultivated Citrus plantations may play an important role in the chemistry of the atmosphere especially in regions such as the Central Valley of California. Moreover, the BVOC emissions from Citrus species have not been characterized in detail and more species-specific inputs for regional models of BVOC emissions are needed. In this study, we measured the physiological parameters and emissions of the most relevant BVOC (oxygenated compounds, monoterpenes, and sesquiterpenes) for four predominant Citrus species planted in California ( Citrus sinensis var. 'Parent Navel', Citrus limon var. 'Meyer', Citrus reticulata var. 'W. Murcott' and 'Clementine'). We used two analytical techniques to measure a full range of BVOC emitted: Proton Transfer Reaction Mass Spectrometry (PTR-MS) and gas chromatography with mass spectrometry. Methanol, followed by acetone and acetaldehyde, were the dominant BVOC emitted from lemon and mandarin trees (basal emission rates up to 300 ng(C) g(DW) -1 h -1), while oxygenated monoterpenes, monoterpenes, and sesquiterpenes were the main BVOC emitted from orange trees (basal emission rates up to = 2500 ng(C) g(DW) -1 h -1). Light and temperature-dependent algorithms were better predictors of methanol, acetaldehyde, acetone, isoprene and monoterpenes for all the Citrus species. Whereas, temperature-dependent algorithms were better predictors of oxygenated monoterpenes, and sesquiterpenes. We observed that flowering increased emissions from orange trees by an order of magnitude with the bulk of BVOC emissions being comprised of monoterpenes, sesquiterpenes, and oxygenated monoterpenes. Chemical speciation of BVOC emissions show that the various classes of terpene

  7. ENZYMATIC KINETIC STUDY HYDROLASE FROM CITRUS

    Directory of Open Access Journals (Sweden)

    Israel Hernández

    2015-09-01

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

  8. Efeito dos compostos naturais bioativos na conservação pós-colheita de frutos de mangueira cv. Tommy Atkins Effects of bioactive natural compounds on the postharvest conservation of mango fruits cv. Tommy Atkins

    Directory of Open Access Journals (Sweden)

    Maria Julia da Silva Cruz

    2010-04-01

    Full Text Available A antracnose causa severos danos na pós-colheita de manga. Como o controle químico tem demonstrado desvantagens, o potencial uso de óleos essenciais para o controle de fitopatógenos tem sido uma alternativa. Neste trabalho, objetvou-se avaliar a eficácia de produtos alternativos no controle da antracnose e na conservação de mangas (Mangifera indica cv. Tommy Atkins tratado com bicarbonato de sódio diluído em água destilada, na concentração de 3% (v/v, via imersão. Como tratamento, foram utilizados os óleos essenciais de Origanum majorana, Citrus sinensis, Cymbopogon citratus e Eucalyptus citriodora, via fumigação, na dosagem de 1000 μL e água destilada via fumigação; todos por 3 minutos. Frutos da Unidade CEASA-Maringá/PR, selecionados, pesados em balança semianalítica, desinfetados em imersão por 3 minutos em solução de hipoclorito de sódio a 0,5% (v/v; foram submetidos aos tratamentos, permanecendo sob condições ambientes (26 ± 2ºC e UR 90 ± 5%. Exceto o tratamento com Citrus sinensis, que proporcionou um pH maior do que a testemunha, diferindo significativamente dos demais tratamentos que elevaram a variável. A redução da acidez em todos os tratamentos e aumentos dos sólidos solúveis totais nos frutos, sendo que o tratamento com bicarbonato de sódio proporcionou 14,42 ºBrix. O número de frutos com antracnose foi menor no tratamento com Citrus sinensis e este diferiu dos demais comprovando o efeito de espécies do gênero Citrus como antifúngicos. O uso de óleos essenciais como o de Citrus sinensis controlou a antracnose e manteve a qualidade dos frutos.The anthracnose causes severe damages to the mango post-harvest. As chemical control has shown disadvantages, the potential of use of essential oils has been an alternative for the phytopathogen control. The objective of the present work was to evaluate the efficacy of alternative products in the anthracnose control and in the conservation of mangos

  9. Identification and functional analysis of Penicillium digitatum genes putatively involved in virulence towards citrus fruit.

    Science.gov (United States)

    López-Pérez, Mario; Ballester, Ana-Rosa; González-Candelas, Luis

    2015-04-01

    The fungus Penicillium digitatum, the causal agent of green mould rot, is the most destructive post-harvest pathogen of citrus fruit in Mediterranean regions. In order to identify P. digitatum genes up-regulated during the infection of oranges that may constitute putative virulence factors, we followed a polymerase chain reaction (PCR)-based suppression subtractive hybridization and cDNA macroarray hybridization approach. The origin of expressed sequence tags (ESTs) was determined by comparison against the available genome sequences of both organisms. Genes coding for fungal proteases and plant cell wall-degrading enzymes represent the largest categories in the subtracted cDNA library. Northern blot analysis of a selection of P. digitatum genes, including those coding for proteases, cell wall-related enzymes, redox homoeostasis and detoxification processes, confirmed their up-regulation at varying time points during the infection process. Agrobacterium tumefaciens-mediated transformation was used to generate knockout mutants for two genes encoding a pectin lyase (Pnl1) and a naphthalene dioxygenase (Ndo1). Two independent P. digitatum Δndo1 mutants were as virulent as the wild-type. However, the two Δpnl1 mutants analysed were less virulent than the parental strain or an ectopic transformant. Together, these results provide a significant advance in our understanding of the putative determinants of the virulence mechanisms of P. digitatum. PMID:25099378

  10. Identification and functional analysis of Penicillium digitatum genes putatively involved in virulence towards citrus fruit.

    Science.gov (United States)

    López-Pérez, Mario; Ballester, Ana-Rosa; González-Candelas, Luis

    2015-04-01

    The fungus Penicillium digitatum, the causal agent of green mould rot, is the most destructive post-harvest pathogen of citrus fruit in Mediterranean regions. In order to identify P. digitatum genes up-regulated during the infection of oranges that may constitute putative virulence factors, we followed a polymerase chain reaction (PCR)-based suppression subtractive hybridization and cDNA macroarray hybridization approach. The origin of expressed sequence tags (ESTs) was determined by comparison against the available genome sequences of both organisms. Genes coding for fungal proteases and plant cell wall-degrading enzymes represent the largest categories in the subtracted cDNA library. Northern blot analysis of a selection of P. digitatum genes, including those coding for proteases, cell wall-related enzymes, redox homoeostasis and detoxification processes, confirmed their up-regulation at varying time points during the infection process. Agrobacterium tumefaciens-mediated transformation was used to generate knockout mutants for two genes encoding a pectin lyase (Pnl1) and a naphthalene dioxygenase (Ndo1). Two independent P. digitatum Δndo1 mutants were as virulent as the wild-type. However, the two Δpnl1 mutants analysed were less virulent than the parental strain or an ectopic transformant. Together, these results provide a significant advance in our understanding of the putative determinants of the virulence mechanisms of P. digitatum.

  11. Application of Antagonistic Yeasts Under Field Conditions and Their Biocontrol Ability Against Postharvest Diseases of Sweet Cherry%田间应用拮抗酵母菌对甜樱桃果实采后病害的防治效果

    Institute of Scientific and Technical Information of China (English)

    田世平; 秦国政; 徐勇; 王友升

    2004-01-01

    研究了应用拮抗酵母菌丝孢酵母(Trichosporon pullulans(Lindner.)Diddens et Lodder)、罗伦隐球酵母(Cryptococcus laurentii(Kuffer.)Skinner)和粘红酵母(Rhodotorula glutinis(Fresenius)Harrison)后拮抗菌在果实表面的繁殖能力以及对不同贮藏条件下甜樱桃(Pranus avivum L.cv.Hongdeng)果实采后病害的防治效果.酵母菌的使用浓度为1×108CFU/mL.结果表明,田间3种拮抗菌都能够在果实表面增值,但是只有C.laurentii和R.glutinis能够持续稳定地生长.C.laurentii的抑病效果最好,它对田间环境和采后低温低氧及高CO2都具有很强的适应能力.%The yeasts Trichosporon pullulans (Lindner.) Diddens et Lodder, Cryptococcuslaurentii (Kuffer.) Skinner and Rhodotorula glutinis (Fresenius) Harrison were sprayed at concentration of 1×108CFU/mL onto sweet cherry (Prunus avivum L. cv. Hongdeng) fruit in two orchards prior to harvest. Survival of these species on fruit surfaces under field conditions was investigated. Also, their biocontrol efficacy against postharvest decay of cherry fruit stored under various conditions was assessed. All three yeasts colonized the surface of sweet cherry fruit. However, only C.laurentii and R. glutinis maintained populations at high and stable levels throughout the 4-d experimental period. C.laurentii was the most effective and promising of the three antagonists. It had strong survival ability on fruit surfaces under field conditions and adaptability to postharvest storage conditions of low temperature, low-O2 and high-CO2 concentratio ns.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-03-01

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

  13. Plant extracts for controlling the post-harvest anthracnose of banana fruit

    Directory of Open Access Journals (Sweden)

    M.E.S. Cruz

    2013-01-01

    Full Text Available In banana, fruit rot is incited by Colletotrichum musae which has been the most serious post-harvest disease of immature and mature fruit. The usual control by fungicides prohibited in many countries reduces their commercial value. Therefore, two experiments were conducted to evaluate the antimicrobial activity of alternative products to the synthetic fungicides. First, berries naturally infected by anthracnose were immersed into Azadirachta indica and citric extracts at 2 and 4% (v/v for 3 minutes and stored for 11 days under environmental conditions. Next, other berries were immersed into essential oil emulsions of Allium sativum, Copaifera langsdorfii, Cinnamomum zeylanicum and Eugenia caryophyllata at 5% for 3 minutes but stored for 11 days. Berries immersed into distilled water were used as control-treatments. The percentage of disease incidence observed in the control-treatment was similar to the ones observed in the extract of A. indica at 2%. The control-treatment showed disease severity of 75.13% and the percentage of disease control was 20.85%. Fruit immersed into distilled water presented less effectiveness than the ones immersed into citric extracts, which promoted the highest effectiveness. Citric extract at 4% was the most efficient treatment because the disease incidence was 19.44%, the disease severity was 9.34% and the disease control was 90.16%. Less severity and, consequently, more disease control were achieved by immersing the berries into the emulsion of essential oil of A. sativum, followed by treatments with C. langsdorfii, E. caryophyllata and C. zeylanicum.

  14. Prediction of postharvest firmness of apple using biological switch model.

    Science.gov (United States)

    van der Sman, R G M; Sanders, M

    2012-10-01

    In this paper we present a model that predicts the softening of apple during ripening in the postharvest phase. Apple ripening starts with an autocatalytic production of ethylene, which triggers a multitude of biochemical processes like the degradation of cell wall material. This triggering of the ripening process has been modelled as a biological switch-using the activator-depleted substrate model, which is proposed earlier by Meinhardt in the field of developmental biology. The model has been calibrated using storage experiments using various apple cultivars. Furthermore, the model is proven to be valid using independent experimental data of Elstar apple under dynamic storage conditions.

  15. Post-harvest losses of fish in the tropics

    OpenAIRE

    Ames, Geoff; Clucas, Ivor; Paul, Susan Scott

    1991-01-01

    Huge quantities of fish are lost after capture. This is an enormous waste of food, especially in the Third World, where much fish production is on a small scale, and where high temperatures make spoilage much more rapid. The situation is increasingly serious, at a time when the world's demand for fish is increasing, yet fishery resources are already under very heavy pressure. This publication seeks to explain just what the 'post-harvest' losses are, and the steps which can be taken to reduce ...

  16. 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.

    Science.gov (United States)

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

    2012-01-01

    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.

  17. 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

    Directory of Open Access Journals (Sweden)

    Stephen Chan Teck Leong

    2012-01-01

    Full Text Available 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.

  18. 柚类柑桔黑点病暴发原因与防治技术%Reason Analysis on Outbreak and Control Technique of Citrus Black-dot Disease of Pomelo

    Institute of Scientific and Technical Information of China (English)

    卢胜进; 蒋仁军; 李爱华; 马新民; 杨永华

    2008-01-01

    通过系统调查、抽样调查、走访、试验、应用等方式对柚类Citrus grandis(L.)Osbeek柑桔黑点病Diaporthe citri(Fawcett)Wolf暴发原因进行分析.结果表明,该病的暴发主要由以下几个方面的因素造成:不良栽培管理使得病源长期大量累积,柚树抗逆性降低;黑蚱蝉等病虫造成大量伤口和枯枝;病害发生时未引起足够重视;柚园小气候适宜该病的发生.采取综合防治技术,突出抓好科学建园、标准化栽培、"资源式"联防联治黑蚱蝉、合理施药、套袋保果,可控制该病发生危害.

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

    Science.gov (United States)

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

    2012-03-14

    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 β-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 β-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

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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