scholarly journals Characterization of an ATP Translocase Identified in the Destructive Plant Pathogen “Candidatus Liberibacter asiaticus”

2009 ◽  
Vol 192 (3) ◽  
pp. 834-840 ◽  
Author(s):  
Cheryl M. Vahling ◽  
Yongping Duan ◽  
Hong Lin
Keyword(s):  
Plant Pathogen ◽  
Bioinformatic Analysis ◽  
Intracellular Bacteria ◽  
Cell Competition ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
High Concentrations ◽  
Obligate Intracellular Bacteria

ABSTRACT ATP/ADP translocases transport ATP across a lipid bilayer, which is normally impermeable to this molecule due to its size and charge. These transport proteins appear to be unique to mitochondria, plant plastids, and obligate intracellular bacteria. All bacterial ATP/ADP translocases characterized thus far have been found in endosymbionts of protozoa or pathogens of higher-order animals, including humans. A putative ATP/ADP translocase was uncovered during the genomic sequencing of the intracellular plant pathogen “Candidatus Liberibacter asiaticus,” the causal agent of citrus huanglongbing. Bioinformatic analysis of the protein revealed 12 transmembrane helices and predicted an isoelectric point of 9.4, both of which are characteristic of this family of proteins. The “Ca. Liberibacter asiaticus” gene (nttA) encoding the translocase was subsequently expressed in Escherichia coli and shown to enable E. coli to import ATP directly into the cell. Competition assays with the heterologous E. coli system demonstrated that the translocase was highly specific for ATP and ADP but that other nucleotides, if present in high concentrations, could also be taken up and/or block the ability of the translocase to import ATP. In addition, a protein homologous to NttA was identified in “Ca. Liberibacter solanacearum,” the bacterium associated with potato zebra chip disease. This is the first reported characterization of an ATP translocase from “Ca. Liberibacter asiaticus,” indicating that some intracellular bacteria of plants also have the potential to import ATP directly from their environment.

scholarly journals Effect of Adjuvants on Oxytetracycline Uptake upon Foliar Application in Citrus

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 677
Author(s):  
Nabil Killiny ◽  
Faraj Hijaz ◽  
Pedro Gonzalez-Blanco ◽  
Shelley E. Jones ◽  
Myrtho O. Pierre ◽  
...  
Keyword(s):  
Foliar Application ◽  
Foliar Spray ◽  
Bacterial Pathogen ◽  
Water Addition ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Trunk Injection ◽  
Citrus Leaves ◽  
Target Effects

Recently in Florida, foliar treatments using products with the antibiotics oxytetracycline and streptomycin have been approved for the treatment of citrus Huanglongbing (HLB), which is caused by the putative bacterial pathogen ‘Candidatus Liberibacter asiaticus’. Herein, we assessed the levels of oxytetracycline and ‘Ca. L. asiaticus’ titers in citrus trees upon foliar applications with and without a variety of commercial penetrant adjuvants and upon trunk injection. The level of oxytetracycline in citrus leaves was measured using an oxytetracycline ELISA kit and ‘Ca. L. asiaticus’ titer was measured using quantitative PCR. Low levels of oxytetracycline were taken up by citrus leaves after foliar sprays of oxytetracycline in water. Addition of various adjuvants to the oxytetracycline solution showed minimal effects on its uptake by citrus leaves. The level of oxytetracycline in leaves from trunk-injected trees was higher than those treated with all foliar applications. The titer of ‘Ca. L. asiaticus’ in the midrib of leaves from trees receiving oxytetracycline by foliar application was not affected after four days and thirty days of application, whereas the titer was significantly reduced in oxytetracycline-injected trees thirty days after treatment. Investigation of citrus leaves using microscopy showed that they are covered by a thick lipidized cuticle. Perforation of citrus leaf cuticle with a laser significantly increased the uptake of oxytetracycline, decreasing the titer of ‘Ca. L. asiaticus’ in citrus leaves upon foliar application. Taken together, our findings indicate that trunk injection is more efficient than foliar spray even after the use of adjuvants. Our conclusion could help in setting useful recommendations for the application of oxytetracycline in citrus to improve tree health, minimize the amount of applied antibiotic, reduce environmental exposure, and limit off-target effects.

Highly sensitive and rapid detection of citrus Huanglongbing pathogen (Candidatus Liberibacter asiaticus) using Cas12a-based methods

2021 ◽  
Author(s):  
Matthew Wheatley ◽  
Yong-Ping Duan ◽  
Yinong Yang
Keyword(s):  
Early Detection ◽  
Nucleic Acids ◽  
Detection Sensitivity ◽  
Sensitive Detection ◽  
Detection Methods ◽  
Candidatus Liberibacter Asiaticus ◽  
Fluorescent Reporter ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus

Citrus Huanglongbing (HLB) or greening is one of the most devastating diseases of citrus worldwide. Sensitive detection of its causal agent, Candidatus Liberibacter asiaticus (CLas), is critical for early diagnosis and successful management of HLB. However, current nucleic acid-based detection methods are often insufficient for the early detection of CLas from asymptomatic tissue, and unsuitable for high-throughput and field-deployable diagnosis of HLB. Here we report the development of the Cas12a-based DETECTR (DNA endonuclease-targeted CRISPR trans reporter) assay for highly specific and sensitive detection of CLas nucleic acids from infected samples. The DETECTR assay, which targets the five-copy nrdB gene specific to CLas, couples isothermal amplification with Cas12a trans-cleavage of fluorescent reporter oligos and enables detection of CLas nucleic acids at the attomolar level. The DETECTR assay was capable of specifically detecting the presence of CLas across different infected citrus, periwinkle and psyllid samples, and shown to be compatible with lateral flow assay technology for potential field-deployable diagnosis. The improvements in detection sensitivity and flexibility of the DETECTR technology position the assay as a potentially suitable tool for early detection of CLas in infected regions.

scholarly journals Home Detection Kit for Candidatus Liberibacter asiaticus (LAS) Associated with Citrus Huanglongbing from Psyllids

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Manjunath L. Keremane ◽  
Chandrika Ramadugu ◽  
Ryo Kubota ◽  
Yongping Duan ◽  
David Hall ◽  
...  
Keyword(s):  
Candidatus Liberibacter Asiaticus ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus

scholarly journals Examination of the Responses of Different Genotypes of Citrus to Huanglongbing (Citrus Greening) Under Different Conditions

2009 ◽  
Vol 99 (12) ◽  
pp. 1346-1354 ◽  
Author(s):  
Svetlana Y. Folimonova ◽  
Cecile J. Robertson ◽  
Stephen M. Garnsey ◽  
Siddarame Gowda ◽  
William O. Dawson
Keyword(s):  
Continuous Light ◽  
Bacterial Titer ◽  
Wide Range ◽  
Growth Room ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Phloem Translocation ◽  
Continue Growth ◽  
Liberibacter Asiaticus ◽  
Tristeza Virus

Citrus Huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide. The causal agent of HLB in Florida is thought to be ‘Candidatus Liberibacter asiaticus’. In this work, we examined the responses of 30 different genotypes of citrus to Florida isolates of ‘Ca. L. asiaticus’ under controlled conditions in the greenhouse or growth room. Although ‘Ca. L. asiaticus’ was able to multiply in all of the plants, a wide range of responses was observed among different hosts. Based on the symptoms developed and the ability of plants to continue growth, the different genotypes were grouped into four categories: sensitive, which exhibited severe chlorosis on leaves, greatly reduced growth, and eventual death; moderately tolerant, which exhibited some scattered distinct symptoms but little or no growth reduction and no plant death; tolerant, which exhibited very minimal symptoms; and genotypes, which exhibited variable reactions. Interestingly, although ‘Ca. L. asiaticus’ was unevenly distributed within each particular plant, comparison of titers of the bacterium in different citrus genotypes revealed that most accumulated similar levels of ‘Ca. L. asiaticus’, demonstrating that there is no strict correlation between bacterial titer and severity of disease. Incubation of infected plants in the growth room with continuous light greatly affected symptoms production by reducing the time before distinctive symptoms developed and significantly increasing severity of chlorosis of leaves of all citrus genotypes. These results provide additional evidence of the correlation between disruption of phloem translocation of carbohydrates during HLB infection and the appearance of chlorotic symptoms in leaves of infected trees. We also examined interaction between ‘Ca. L. asiaticus’ and Citrus tristeza virus, which usually occurs in trees that become infected with HLB, and found no synergistic effect of the two pathogens. We trust that observations reported here will provide reagents for further examination of the ‘Ca. L. asiaticus’–citrus interaction to advance the understanding of how ‘Ca. L. asiaticus’ causes disease and to develop methods or trees to overcome the disease.

Regional Spatial-Temporal Spread of Citrus Huanglongbing Is Affected by Rain in Florida

2018 ◽  
Vol 108 (12) ◽  
pp. 1420-1428 ◽  
Author(s):  
M. M. Shimwela ◽  
T. S. Schubert ◽  
M. Albritton ◽  
S. E. Halbert ◽  
D. J. Jones ◽  
...  
Keyword(s):  
Large Scale ◽  
Disease Incidence ◽  
Kernel Density ◽  
Candidatus Liberibacter Asiaticus ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Density Analysis ◽  
Liberibacter Asiaticus ◽  
Kernel Density Analysis ◽  
Temporal Spread

Citrus huanglongbing (HLB), associated with ‘Candidatus Liberibacter asiaticus’ (Las), disseminated by Asian citrus psyllid (ACP), has devastated citrus in Florida since 2005. Data on HLB occurrence were stored in databases (2005 to 2012). Cumulative HLB-positive citrus blocks were subjected to kernel density analysis and kriging. Relative disease incidence per county was calculated by dividing HLB numbers by relative tree numbers and maximum incidence. Spatiotemporal HLB distributions were correlated with weather. Relative HLB incidence correlated positively with rainfall. The focus expansion rate was 1626 m month−1, similar to that in Brazil. Relative HLB incidence in counties with primarily large groves increased at a lower rate (0.24 year−1) than in counties with smaller groves in hotspot areas (0.67 year−1), confirming reports that large-scale HLB management may slow epidemic progress.

scholarly journals Historical Perspectives, Management, and Current Research of Citrus HLB in Guangdong Province of China, Where the Disease has been Endemic for Over a Hundred Years

2018 ◽  
Vol 108 (11) ◽  
pp. 1224-1236 ◽  
Author(s):  
Zheng Zheng ◽  
Jianchi Chen ◽  
Xiaoling Deng
Keyword(s):  
Southern China ◽  
Candidatus Liberibacter Asiaticus ◽  
Sequencing Technology ◽  
Next Generation Sequencing Technology ◽  
Historical Perspectives ◽  
Citrus Production ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Generation Sequencing

Citrus huanglongbing (HLB) is a highly destructive disease currently threatening citrus production worldwide. In China, the disease is exclusively associated with ‘Candidatus Liberibacter asiaticus’, a nonculturable proteobacterium. HLB was observed in Guangdong of China over a hundred years ago. Researchers and citrus growers have been battling with the disease through vigorous research and have exercised various control practices. Much of the early work was not well known outside China. This review is intended to fill in gaps of historical information by reviewing selected literature records. Along the way, the HLB system within southern China was evaluated. Emphases were on comparison of symptomatology, evolution of etiology, control practices, and impacts of using next-generation sequencing technology for ‘Ca. L. asiaticus’ research and detection.

scholarly journals First report on molecular evidence of Candidatus Liberibacter asiaticus associated with citrus Huanglongbing in Venezuela

2020 ◽  
Vol 102 (4) ◽  
pp. 1333-1333
Author(s):  
Edgloris Marys ◽  
Eduardo Rodríguez-Román ◽  
Rafael Mejías ◽  
Alexander Mejías ◽  
Mailyn Mago ◽  
...  
Keyword(s):  
Molecular Evidence ◽  
Candidatus Liberibacter Asiaticus ◽  
First Report ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus

scholarly journals Probing Behavior of Diaphorina citri (Hemiptera: Liviidae) on Valencia Orange Influenced by Sex, Color, and Size

2020 ◽  
Vol 20 (2) ◽  
Author(s):  
Timothy A Ebert ◽  
Michael E Rogers
Keyword(s):  
Body Size ◽  
Model Performance ◽  
Diaphorina Citri ◽  
Probing Behavior ◽  
Valencia Orange ◽  
Improve Model ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Improve Model Performance

Abstract Candidatus Liberibacter asiaticus Jagoueix, Bové, and Garnier (Rhizobiales: Rhizobiaceae) is transmitted by the psyllid Diaphorina citri Kuwayama and putatively causes Huanglongbing disease in citrus. Huanglongbing has reduced yields by 68% relative to pre-disease yields in Florida. Disease management is partly through vector control. Understanding vector biology is essential in this endeavor. Our goal was to document differences in probing behavior linked to sex. Based on both a literature review and our results, we conclude that there is either no effect of sex or that identifying such an effect requires a sample size at least four times larger than standard methodologies. Including both color and sex in statistical models did not improve model performance. Both sex and color are correlated with body size, and body size has not been considered in previous studies on sex in D. citri in terms of probing behavior. An effect of body size was found wherein larger psyllids took longer to reach ingestion behaviors and larger individuals spent more time-ingesting phloem, but these relationships explained little of the variability in these data. We suggest that the effects of sex can be ignored when running EPG experiments on healthy psyllids.

scholarly journals Latency and Persistence of ‘Candidatus Liberibacter asiaticus’ in Its Psyllid Vector, Diaphorina citri (Hemiptera: Liviidae)

2017 ◽  
Vol 107 (3) ◽  
pp. 264-272 ◽  
Author(s):  
Maria Cristina Canale ◽  
Arthur Fernando Tomaseto ◽  
Marineia de Lara Haddad ◽  
Helvécio Della Coletta-Filho ◽  
João Roberto Spotti Lopes
Keyword(s):  
Latent Period ◽  
Acquisition Time ◽  
Diaphorina Citri ◽  
Candidatus Liberibacter Asiaticus ◽  
Old Adults ◽  
Sequential Inoculation ◽  
Candidatus Liberibacter ◽  
Citrus Huanglongbing ◽  
Liberibacter Asiaticus ◽  
Series Of Experiments

Although ‘Candidatus Liberibacter asiaticus’ (Las) is a major pathogen associated with citrus huanglongbing (HLB), some characteristics of transmission by the psyllid vector Diaphorina citri are not fully understood. We examined the latent period and persistence of transmission of Las by D. citri in a series of experiments at 25°C, in which third-instar psyllid nymphs and 1-week-old adults were confined on infected citrus for an acquisition access period (AAP), and submitted to sequential inoculation access periods (IAPs) on healthy citrus seedlings. The median latent period (LP50, i.e., acquisition time after which 50% of the individuals can inoculate) of 16.8 and 17.8 days for psyllids that acquired Las as nymphs and adults, respectively, was determined by transferring single individuals in 48-h IAPs. Inoculation events were intermittent and randomly distributed over the IAPs, but were more frequent after acquisition by nymphs. A minimum latent period of 7 to 10 days was observed by transferring groups of 10 psyllids in 48-h IAPs, after a 96-h AAP by nymphs. Psyllids transmitted for up to 5 weeks, when submitted to sequential 1-week IAPs after a 14-day AAP as nymphs. The long latent period and persistence of transmission are indirect evidences of circulative propagation of Las in D. citri.

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