Comparison between Serological and Molecular Detection of Citrus Canker Pathogen (Xanthomonas axonopodis pv. citri)

2011 ◽  
Author(s):  
Kutudat-Cairns Mariena
2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
María Laura Tondo ◽  
Ramon Hurtado-Guerrero ◽  
Eduardo A. Ceccarelli ◽  
Milagros Medina ◽  
Elena G. Orellano ◽  
...  

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.


Microbiology ◽  
2011 ◽  
Vol 157 (3) ◽  
pp. 819-829 ◽  
Author(s):  
Florencia Malamud ◽  
Pablo S. Torres ◽  
Roxana Roeschlin ◽  
Luciano A. Rigano ◽  
Ramón Enrique ◽  
...  

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.


PLoS ONE ◽  
2009 ◽  
Vol 4 (2) ◽  
pp. e4358 ◽  
Author(s):  
Natalia Gottig ◽  
Betiana S. Garavaglia ◽  
Cecilia G. Garofalo ◽  
Elena G. Orellano ◽  
Jorgelina Ottado

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1048E-1049 ◽  
Author(s):  
Greg McCollum ◽  
Kim Bowman ◽  
Tim Gottwald

Citrus bacterial canker [causal agent Xanthomonas axonopodis pv. citri (Xac)] is a serious threat to the citrus industry. Currently, there are no effective means to control citrus canker. Our objective was to determine the resistance of selected citrus species, citrus hybrids, and citrus relatives to Xac. Our first experiment focused on determining if differences in resistance exist among 20 C. reticulata genotypes and included three other citrus species and citrus relatives (Glycosmis pentaphylla and Clausena hardimandiana). Plants were inoculated with Xac strain A either by injection infiltration or needle-prick. Our second experiment included 10 members of the genus Citrus and Poncirus trifoliata, representing a total of 31 different selections. Plants were needle-prick inoculated with both Xac strain A and Xac strain A Wellington (AW). All inoculations were done using suspensions of Xac at a concentration of 104 cfu/mL. In both experiments, there were highly significant differences among genotypes in response to inoculation with Xac. In the first experiment, regardless of inoculation method, G. pentaphylla and C. hardimandiana were found to be highly resistant to Xac, whereas C. paradisi was least resistant. In the second experiment for both Xac strain A and AW, Chinotto sour orange, Carrizo citrange, Eustis limequat, and P. trifoliata were the most resistant. Thornless key lime × Meiwa kumquat hybrids showed a range of resistance from among the most susceptible to among the most resistant. Our results expand on previous studies on resistance of citrus and citrus relatives to Xac and indicate that there may be potential for increasing resistance by breeding using selected parents.


2021 ◽  
Vol 18 ◽  
Author(s):  
Miguel Ángel Castillo ◽  
María Guadalupe Reyes ◽  
Elsa Mónica Farfán Torres ◽  
María Laura Uriburu

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.


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