scholarly journals Field Identification of Citrus Canker Symptoms and Decontamination Procedures

EDIS ◽  
2019 ◽  
Vol 2005 (13) ◽  
Author(s):  
Mongi Zekri ◽  
Holly L. Chamberlain ◽  
Pete Timmer ◽  
Pamela D. Roberts ◽  
Rosa M. Muchovej
Keyword(s):  
Bacterial Pathogen ◽  
Citrus Canker ◽  
Fruit Trees ◽  
Publication Date ◽  
Xanthomonas Axonopodis ◽  
Fruit Drop ◽  
Field Identification ◽  
Citrus Varieties ◽  
Serious Disease ◽  
General Tree

Citrus canker, caused by a bacterial pathogen Xanthomonas axonopodis pv. citri, is a serious disease of most citrus varieties. The disease causes necrotic lesions on leaves, stems, and fruit (Figure 1 and Figure 2). Severe infestation can cause defoliation, premature fruit drop, twig dieback, general tree decline, and very bad blemishes on fruit. Trees infected with citrus canker become weak, unproductive, and unprofitable. This document is PP-214, one of a series of the Plant Pathology Department, UF/IFAS Extension. Original publication date October 2005. PP-214/PP136: Field Identification of Citrus Canker Symptoms and Decontamination Procedures (ufl.edu)

scholarly journals CROP ALERT: A Citrus Canker Fact Sheet for Homeowners

EDIS ◽  
1969 ◽  
Vol 2003 (11) ◽  
Author(s):  
H. L. Chamberlain ◽  
Pamela D. Roberts ◽  
Lavern W. Timmer ◽  
Kuang-Ren Chung ◽  
Mongi Zekri
Keyword(s):  
Bacterial Pathogen ◽  
Citrus Canker ◽  
Cooperative Extension Service ◽  
Extension Service ◽  
Publication Date ◽  
University Of Florida ◽  
Xanthomonas Axonopodis ◽  
Fact Sheet ◽  
Serious Disease ◽  
Host Tissues

Citrus canker (CC) is caused by the bacterial pathogen Xanthomonas axonopodis pv. citri. The pathogen enters host tissues through wounds and natural openings called stomata. It is a serious disease of all citrus and some citrus relatives. This document is PP194, one of a series of the Plant Pathology Department, Florida Cooperative Extension Service, Insitute of Food and Agricultural Sciences, University of Florida. Original Publication Date: September 2001. Reviewed: June 2003.  PP194/PP116: Homeowner Fact Sheet: Citrus Canker (ufl.edu)

Inhibition of the Citrus Bacterial Pathogen Xanthomonas axonopodis pv. citri through Aloysia gratissima Essential Oil and Flourensia spp. Extracts and Prenylflavonoids

2021 ◽  
Vol 18 ◽  
Author(s):  
Miguel Ángel Castillo ◽  
María Guadalupe Reyes ◽  
Elsa Mónica Farfán Torres ◽  
María Laura Uriburu
Keyword(s):  
Antimicrobial Activity ◽  
Essential Oil ◽  
Essential Oils ◽  
Antimicrobial Agents ◽  
Bacterial Pathogen ◽  
Tween 80 ◽  
Citrus Canker ◽  
Xanthomonas Axonopodis ◽  
Plant Essential Oils ◽  
Pure Compounds

Background: Xanthomonas axonopodis pv. citri is a gram-negative bacterium that affects citrus crops, causing a disease known as citrus canker. Although essential oils and other compounds isolated from plants represent a natural alternative to treat this disease, they have the disadvantage of having low solubility in the media in which the bioassays to determine antimicrobial activity are performed. This has led several researchers to evaluate the solubility of plant essential oils in alternative solvents. Objectives: The aim of this study was to evaluate the solubility of the essential oil from Aloysia gratissima as well as that of low-polarity extracts and pure compounds of the genus Flourensia in diluted agar/Tween 80 solutions to test and improve their antimicrobial activity against Xanthomonas axonopodis pv. citri. Methods: Antimicrobial activity against Xanthomonas axonopodis pv. citri was determined by bioautography, agar diffusion, and microdilution methods. Results: The A. gratissima oil showed increased activity in the agar (0.15 % m/v)/Tween80 (0.5 % v/v) 1:1 mixture, with MIC values ranging from 75 to 100 µL/mL, while Flourensia spp. extracts were more soluble in agar solution (0.15 % m/v). The pure compounds tested presented MIC values ranging from 50 to 150 µg/mL. Conclusion: The proven antimicrobial activity of both Aloysia gratissima essential oil and Flourensia spp. extracts and pure compounds allows proposing these natural products as potential antimicrobial agents in the control of citrus canker.

scholarly journals Crystal Structure of the FAD-Containing Ferredoxin-NADP+Reductase from the Plant PathogenXanthomonas axonopodispv. citri

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
María Laura Tondo ◽  
Ramon Hurtado-Guerrero ◽  
Eduardo A. Ceccarelli ◽  
Milagros Medina ◽  
Elena G. Orellano ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Transfer Process ◽  
Plant Pathogen ◽  
Active Site ◽  
Functional Divergence ◽  
Hydride Transfer ◽  
Citrus Canker ◽  
Xanthomonas Axonopodis ◽  
C Terminus

We have solved the structure of ferredoxin-NADP(H) reductase, FPR, from the plant pathogenXanthomonas axonopodispv. citri, responsible for citrus canker, at a resolution of 1.5 Å. This structure reveals differences in the mobility of specific loops when compared to other FPRs, probably unrelated to the hydride transfer process, which contributes to explaining the structural and functional divergence between the subclass I FPRs. Interactions of the C-terminus of the enzyme with the phosphoadenosine of the cofactor FAD limit its mobility, thus affecting the entrance of nicotinamide into the active site. This structure opens the possibility of rationally designing drugs against theX. axonopodispv. citri phytopathogen.

scholarly journals CitrusKB: a comprehensive knowledge base for transcriptome and interactome of Citrus spp. infected by Xanthomonas citri subsp. citri at different infection stages

Database ◽  
2020 ◽  
Vol 2020 ◽  
Author(s):  
Adriano Ferrasa ◽  
Mayara M Murata ◽  
Teresa D C G Cofre ◽  
Juliana S Cavallini ◽  
Gustavo Peron ◽  
...  
Keyword(s):  
Knowledge Base ◽  
Citrus Canker ◽  
Limited Information ◽  
Xanthomonas Citri ◽  
Comprehensive Knowledge ◽  
Genetic Mechanisms ◽  
Serious Disease ◽  
Canker Development ◽  
User Friendly

Abstract Citrus canker type A is a serious disease caused by Xanthomonas citri subsp. citri (X. citri), which is responsible for severe losses to growers and to the citrus industry worldwide. To date, no canker-resistant citrus genotypes are available, and there is limited information regarding the molecular and genetic mechanisms involved in the early stages of the citrus canker development. Here, we present the CitrusKB knowledge base. This is the first in vivo interactome database for different citrus cultivars, and it was produced to provide a valuable resource of information on citrus and their interaction with the citrus canker bacterium X. citri. CitrusKB provides tools for a user-friendly web interface to let users search and analyse a large amount of information regarding eight citrus cultivars with distinct levels of susceptibility to the disease, with controls and infected plants at different stages of infection by the citrus canker bacterium X. citri. Currently, CitrusKB comprises a reference citrus genome and its transcriptome, expressed transcripts, pseudogenes and predicted genomic variations (SNPs and SSRs). The updating process will continue over time by the incorporation of novel annotations and analysis tools. We expect that CitrusKB may substantially contribute to the field of citrus genomics. CitrusKB is accessible at http://bioinfo.deinfo.uepg.br/citrus. Users can download all the generated raw sequences and generated datasets by this study from the CitrusKB website.

scholarly journals Characteristics of Citrus Canker Lesions Associated with Premature Drop of Sweet Orange Fruit

2019 ◽  
Vol 109 (1) ◽  
pp. 44-51 ◽  
Author(s):  
Fabrício E. Lanza ◽  
Weber Marti ◽  
Geraldo J. Silva ◽  
Franklin Behlau
Keyword(s):  
Sweet Orange ◽  
Linear Regression Analysis ◽  
Negative Relationship ◽  
Citrus Fruit ◽  
Citrus Canker ◽  
Multiple Linear Regression Analysis ◽  
Detachment Force ◽  
Fruit Drop ◽  
Orange Fruit ◽  
The Relationship

During the development of a citrus fruit, many cycles of infection by Xanthomonas citri subsp. citri may occur leading to the development of a range of characteristics of citrus canker lesions scattered across the fruit surface. This study aimed to determine whether the size of the lesions, their distance from the peduncle, and the number and time of appearance of the lesions on fruit of sweet orange were associated with premature fruit drop. A multiple linear regression analysis revealed a negative relationship between the fruit detachment force and the lesion diameter, the proximity of the nearest lesion to the peduncle and the number of lesions. A survival analysis demonstrated that these characteristics significantly influenced the probability and the time that a cankered fruit remained attached to the tree. More than 90% of dropped fruit had large lesions (>5 mm) but not all fruit with large lesions dropped before harvest. Approximately 50% of the harvested fruit had lesions >5 mm. On the harvested fruit remaining on the tree, although large, the lesions had a smaller diameter, were located farther from the peduncle, and were less numerous than those observed on dropped fruit. Small canker lesions neither reduced the detachment force nor the survival of fruit in the tree. The earlier a fruit expressed canker symptoms, the higher the probability the fruit developed large lesions near the peduncle and/or developed lesions in greater numbers. This study provides a better understanding on the relationship between the time of appearance of lesions of citrus canker on fruit and premature fruit drop. This information defines the critical period for fruit protection and may be used to improve disease management.

scholarly journals P27 A scoping review to support the development of pGALSplus: a multi-professional tool and educational resource

Rheumatology ◽  
2019 ◽  
Vol 58 (Supplement_4) ◽  
Author(s):  
Vicky Mercer ◽  
Nicola Smith ◽  
Sharmila Jandial ◽  
Helen Foster
Keyword(s):  
Scoping Review ◽  
Developmental Coordination Disorder ◽  
Conflicts Of Interest ◽  
Paediatric Rheumatology ◽  
Assessment Tools ◽  
Screening Tools ◽  
Publication Date ◽  
The North ◽  
Training Resources ◽  
Serious Disease

Poster presentation Tuesday 8 October Background Musculoskeletal (MSK) problems in children and young people (CYP) are common. The majority will present to healthcare professionals in the community but it can be challenging to identify those with serious disease requiring onward referral. pGALS (paediatric Gait, Arms, Legs and Spine) was developed as a simple, quick MSK clinical assessment to discern abnormal joints, initially within paediatric rheumatology and later targeted at non-specialists. Anecdotally, pGALS can detect joint and functional problems in CYP with other serious conditions, but alone is unlikely to be specific enough. It is unknown whether a pGALSplus assessment is practical. Our aim was to scope the literature about MSK assessments applicable to CYP used in clinical practice, focusing on evidence of validity in the context of diagnosis and assessment of juvenile idiopathic arthritis (JIA), mucopolysaccharidoses (MPS), Muscular dystrophy (MD) and developmental coordination disorder (DCD) to develop an extended pGALS. Methods Scoping review using the Newcastle University Library search tool (which includes several databases) and Google Scholar, and consulting NICE guidance/pathways. Search terms included dyspraxia, paediatric MSK assessment, screening tools, balance, and rheumatology, assessment tools for MD, MPS, and JIA. Studies cited within relevant articles uncovered through searches were also checked. The search was conducted between 1 October and 1 December 2018. Publication date was limited to post-1998, language did not constitute as exclusion criteria unless translation was unavailable. Results 32 journal articles were deemed appropriate, describing specific assessment or screening tools in the context of diagnosis of our target conditions. Within DCD, motor co-ordination test batteries aid diagnosis as part of specialist assessment, but are regarded as too lengthy for the purpose of screening; a questionnaire may be useful as a first-step diagnostic tool, along with an assessment of static balance (found to be significantly worse in children with DCD). In paediatric rheumatology, pGALS is the only validated screening tool to discern normal from abnormal. Other tools to assess health and wellbeing, disability and function are validated in the context of established disease only. For neuromuscular conditions the North Star Ambulatory Assessment is valid, reliable and practical as a functional assessment, and includes activities that are necessary to remain functionally ambulant. With regards to MPS, searches did not reveal specific MSK tests, but evidence suggests that skeletal malformations and joint problems were the most frequently presenting signs. pGALS performs well to identify abnormal joints with restriction within an MPS group. Conclusion This review supports the development of pGALSplus; a toolkit to facilitate identification and assessment of CYP with potentially serious MSK disease. pGALSplus will be targeted at community-based clinicians and will likely include physical examination, questionnaire(s) and appropriate adjuncts. Our group is currently developing pGALSplus, aiming to describe feasibility and acceptability, and develop educational and training resources, aimed at multi-professionals. Conflicts of Interest The authors declare no conflicts of interest.

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

Microbiology ◽  
2011 ◽  
Vol 157 (3) ◽  
pp. 819-829 ◽  
Author(s):  
Florencia Malamud ◽  
Pablo S. Torres ◽  
Roxana Roeschlin ◽  
Luciano A. Rigano ◽  
Ramón Enrique ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Cell Signalling ◽  
Citrus Canker ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Slight Reduction ◽  
Xanthomonas Axonopodis ◽  
Abiotic Surfaces ◽  
Biofilm Development ◽  
Surface Translocation

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

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