Citrus Canker Eradication

1929 ◽  
Vol 22 (4) ◽  
pp. 656-656
Author(s):  
K. F. Kellerman
Keyword(s):  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Plinio S. Vieira ◽  
Isabela M. Bonfim ◽  
Evandro A. Araujo ◽  
Ricardo R. Melo ◽  
Augusto R. Lima ◽  
...  

AbstractXyloglucans are highly substituted and recalcitrant polysaccharides found in the primary cell walls of vascular plants, acting as a barrier against pathogens. Here, we reveal that the diverse and economically relevant Xanthomonas bacteria are endowed with a xyloglucan depolymerization machinery that is linked to pathogenesis. Using the citrus canker pathogen as a model organism, we show that this system encompasses distinctive glycoside hydrolases, a modular xyloglucan acetylesterase and specific membrane transporters, demonstrating that plant-associated bacteria employ distinct molecular strategies from commensal gut bacteria to cope with xyloglucans. Notably, the sugars released by this system elicit the expression of several key virulence factors, including the type III secretion system, a membrane-embedded apparatus to deliver effector proteins into the host cells. Together, these findings shed light on the molecular mechanisms underpinning the intricate enzymatic machinery of Xanthomonas to depolymerize xyloglucans and uncover a role for this system in signaling pathways driving pathogenesis.


2021 ◽  
Vol 146 ◽  
pp. 105679
Author(s):  
Franklin Behlau ◽  
Alexandre Paloschi ◽  
Tamiris G.S. Marin ◽  
Talita A. Santos ◽  
Henrique Ferreira ◽  
...  

2021 ◽  
Vol 9 (6) ◽  
pp. 1176
Author(s):  
Simone Cristina Picchi ◽  
Laís Moreira Granato ◽  
Maria Júlia Festa Franzini ◽  
Maxuel Oliveira Andrade ◽  
Marco Aurélio Takita ◽  
...  

Xanthomonas citri subsp. citri (X. citri) is a plant pathogenic bacterium causing citrus canker disease. The xanA gene encodes a phosphoglucomutase/phosphomannomutase protein that is a key enzyme required for the synthesis of lipopolysaccharides and exopolysaccharides in Xanthomonads. In this work, firstly we isolated a xanA transposon mutant (xanA::Tn5) and analyzed its phenotypes as biofilm formation, xanthan gum production, and pathogenesis on the sweet orange host. Moreover, to confirm the xanA role in the impaired phenotypes we further produced a non-polar deletion mutant (ΔxanA) and performed the complementation of both xanA mutants. In addition, we analyzed the percentages of the xanthan gum monosaccharides produced by X. citri wild-type and xanA mutant. The mutant strain had higher ratios of mannose, galactose, and xylose and lower ratios of rhamnose, glucuronic acid, and glucose than the wild-type strain. Such changes in the saccharide composition led to the reduction of xanthan yield in the xanA deficient strain, affecting also other important features in X. citri, such as biofilm formation and sliding motility. Moreover, we showed that xanA::Tn5 caused no symptoms on host leaves after spraying, a method that mimetics the natural infection condition. These results suggest that xanA plays an important role in the epiphytical stage on the leaves that is essential for the successful interaction with the host, including adaptive advantage for bacterial X. citri survival and host invasion, which culminates in pathogenicity.


2009 ◽  
Vol 125 (1) ◽  
pp. 23-38 ◽  
Author(s):  
C. H. Bock ◽  
T. R. Gottwald ◽  
P. E. Parker ◽  
A. Z. Cook ◽  
F. Ferrandino ◽  
...  
Keyword(s):  

Plant Disease ◽  
2004 ◽  
Vol 88 (10) ◽  
pp. 1056-1060 ◽  
Author(s):  
Z. Viloria ◽  
D. L. Drouillard ◽  
J. H. Graham ◽  
J. W. Grosser

Resistance of citrus genotypes to Xanthomonas axonopodis pv. citri, the cause of Asiatic citrus canker (ACC), was evaluated by injection infiltration of 103 and 104 CFU/ml through stomates on the abaxial surface of immature leaves. Citrus genotypes for screening comprised two autotetraploids and nine triploid hybrids of ‘Lakeland’ limequat (Citrus aurantifolia × Fortunella japonica) and their progenitors (‘Lakeland’ limequat, the autotetraploids ‘Femminello’ lemon (Citrus limon) and ‘Giant Key’ lime (C. aurantifolia), and the somatic hybrids ‘Key’ [also known as ‘Mexican’] lime + ‘Valencia’ orange and ‘Hamlin’ orange + ‘Femminello’ lemon). ‘Meiwa’ kumquat (Fortunella crassifolia) and ‘Pineapple’ sweet orange (C. sinensis) were used as known resistant and susceptible standards, respectively. Lesion number per inoculation site and bacterial population per lesion were recorded 15 to 19 days after inoculation. The assay was performed four times during a spring-summer-fall period under greenhouse conditions. Canker lesions were consistently produced by stomatal inoculation with 104 but not 103 CFU/ml. Susceptible and resistant genotypes were separated based on lesion number per inoculation site and bacterial population per lesion. Spearman's rank correlation analysis for lesion numbers on 15 genotypes common to all four assays showed significant correlations among the genotype rankings. Genotype rankings were also significantly correlated between the two bacterial population assays. Lesion number per inoculation site is sufficient for assessment of resistance of citrus genotypes to ACC without the necessity of conducting bacterial population assays. ‘Lakeland’ limequat is a promising seed parent for breeding acid citrus fruit that is resistant to ACC.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Simone Cristina Picchi ◽  
Mariana de Souza e Silva ◽  
Luiz Leonardo Saldanha ◽  
Henrique Ferreira ◽  
Marco Aurélio Takita ◽  
...  

AbstractN-Acetylcysteine (NAC) is an antioxidant, anti-adhesive, and antimicrobial compound. Even though there is much information regarding the role of NAC as an antioxidant and anti-adhesive agent, little is known about its antimicrobial activity. In order to assess its mode of action in bacterial cells, we investigated the metabolic responses triggered by NAC at neutral pH. As a model organism, we chose the Gram-negative plant pathogen Xanthomonas citri subsp. citri (X. citri), the causal agent of citrus canker disease, due to the potential use of NAC as a sustainable molecule against phytopathogens dissemination in citrus cultivated areas. In presence of NAC, cell proliferation was affected after 4 h, but damages to the cell membrane were observed only after 24 h. Targeted metabolite profiling analysis using GC–MS/TOF unravelled that NAC seems to be metabolized by the cells affecting cysteine metabolism. Intriguingly, glutamine, a marker for nitrogen status, was not detected among the cells treated with NAC. The absence of glutamine was followed by a decrease in the levels of the majority of the proteinogenic amino acids, suggesting that the reduced availability of amino acids affect protein synthesis and consequently cell proliferation.


2007 ◽  
Vol 8 (1) ◽  
pp. 22 ◽  
Author(s):  
Tim R. Gottwald ◽  
Michael Irey

The impact of 2005 Hurricane Wilma on the dissemination of Xanthomonas axonopodis pv. citri (Xac), the cause of Asiatic citrus canker (ACC), and subsequent disease development was examined and predictions for the areas into which Xac was likely to have spread from known sources of infection were developed. In addition, the effect of the current 579-m (1900-ft) ACC eradication protocol, resulting in removal of all “exposed trees” with a 579-m radius of a known Xac-infected tree, was calculated via GIS analysis and expressed as the predicted “impacted area.” The GIS calculations were based on the extension of the previous published wind-rain index vector (WRIV) model. The model extension consisted of the incorporation of an estimate of distance of spread due to various combinations of wind and rain from data collected during the 2004 hurricane season. An inverse power law dissemination function was used to describe regional dispersal from a point focus of Xac infection. Alternative eradication protocol (distances) to the 579-m protocol were evaluated in association with the GIS analyses and used to examine the effect of eradication distance on predicted “impacted area.” The results of these analyses were used by state and federal regulatory agencies and commercial citrus producer groups to evaluate the feasibility of continued ACC eradication. Accepted for publication 23 January 2007. Published 5 April 2007.


2010 ◽  
Vol 26 (1) ◽  
pp. 90-92 ◽  
Author(s):  
Ki-Woo Kim ◽  
In-Jung Lee ◽  
Jae-Wook Hyun ◽  
Yong-Hoon Lee ◽  
Eun-Woo Park

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