Foliar Application of Biofilm Formation–Inhibiting Compounds Enhances Control of Citrus Canker Caused by Xanthomonas citri subsp. citri

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.

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Modified Monosaccharides Content of Xanthan Gum Impairs Citrus Canker Disease by Affecting the Epiphytic Lifestyle of Xanthomonas citri subsp. citri

Microorganisms ◽

10.3390/microorganisms9061176 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1176

Author(s):

Simone Cristina Picchi ◽

Laís Moreira Granato ◽

Maria Júlia Festa Franzini ◽

Maxuel Oliveira Andrade ◽

Marco Aurélio Takita ◽

...

Keyword(s):

Biofilm Formation ◽

Xanthan Gum ◽

Wild Type Strain ◽

Natural Infection ◽

Citrus Canker ◽

Wild Type ◽

Xanthomonas Citri ◽

Canker Disease ◽

Key Enzyme ◽

Citrus Canker Disease

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.

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The ecnA Antitoxin Is Important Not Only for Human Pathogens: Evidence of Its Role in the Plant Pathogen Xanthomonas citri subsp. citri

Journal of Bacteriology ◽

10.1128/jb.00796-18 ◽

2019 ◽

Vol 201 (20) ◽

Cited By ~ 2

Author(s):

Laís Moreira Granato ◽

Simone Cristina Picchi ◽

Maxuel de Oliveira Andrade ◽

Paula Maria Moreira Martins ◽

Marco Aurélio Takita ◽

...

Keyword(s):

Biofilm Formation ◽

Host Plants ◽

Citrus Canker ◽

Human Pathogens ◽

Xanthomonas Citri ◽

Content Type ◽

Canker Disease ◽

Bacterial Pathogenicity ◽

Wide Range ◽

Host Infection

ABSTRACT Xanthomonas citri subsp. citri causes citrus canker disease worldwide in most commercial varieties of citrus. Its transmission occurs mainly by wind-driven rain. Once X. citri reaches a leaf, it can epiphytically survive by forming a biofilm, which enhances the persistence of the bacteria under different environmental stresses and plays an important role in the early stages of host infection. Therefore, the study of genes involved in biofilm formation has been an important step toward understanding the bacterial strategy for survival in and infection of host plants. In this work, we show that the ecnAB toxin-antitoxin (TA) system, which was previously identified only in human bacterial pathogens, is conserved in many Xanthomonas spp. We further show that in X. citri, ecnA is involved in important processes, such as biofilm formation, exopolysaccharide (EPS) production, and motility. In addition, we show that ecnA plays a role in X. citri survival and virulence in host plants. Thus, this mechanism represents an important bacterial strategy for survival under stress conditions. IMPORTANCE Very little is known about TA systems in phytopathogenic bacteria. ecnAB, in particular, has only been studied in bacterial human pathogens. Here, we showed that it is present in a wide range of Xanthomonas sp. phytopathogens; moreover, this is the first work to investigate the functional role of this TA system in Xanthomonas citri biology, suggesting an important new role in adaptation and survival with implications for bacterial pathogenicity.

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Effect of a Berry Polyphenolic Fraction on Biofilm Formation, Adherence Properties and Gene Expression of Streptococcus mutans and Its Biocompatibility with Oral Epithelial Cells

Antibiotics ◽

10.3390/antibiotics10010046 ◽

2021 ◽

Vol 10 (1) ◽

pp. 46

Author(s):

Mariem Souissi ◽

Amel Ben Lagha ◽

Kamel Chaieb ◽

Daniel Grenier

Keyword(s):

Epithelial Cells ◽

Streptococcus Mutans ◽

Biofilm Formation ◽

Cell Model ◽

Pcr Analysis ◽

Adhesion Properties ◽

Oral Epithelial Cells ◽

Polymerase Chain ◽

Oral Epithelial ◽

Wild Blueberry

The ability of Streptococcus mutans to adhere to oral surfaces and form biofilm is a key step in the tooth decay process. The aim of this study was to investigate a berry (wild blueberry, cranberry, and strawberry) polyphenolic fraction, commercialized as Orophenol®, for its antibacterial, anti-biofilm, and anti-adhesion properties on S. mutans. Moreover, the biocompatibility of the fraction with human oral epithelial cells was assessed. Phenolic acids, flavonoids (flavonols, anthocyanins, flavan-3-ols), and procyanidins made up 10.71%, 19.76%, and 5.29% of the berry polyphenolic fraction, respectively, as determined by chromatography and mass spectrometry. The berry polyphenolic preparation dose-dependently inhibited S. mutans biofilm formation while not reducing bacterial growth. At concentrations ranging from 250 to 1000 µg/mL, the fraction inhibited the adhesion of S. mutans to both saliva-coated hydroxyapatite and saliva-coated nickel–chrome alloy. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed that incubating S. mutans with the berry polyphenolic fraction was associated with a reduced expression of luxS gene, which regulates quorum sensing in S. mutans. The berry fraction did not show any significant cytotoxicity in an oral epithelial cell model. In conclusion, Orophenol®, which is a mixture of polyphenols from wild blueberry, cranberry and strawberry, possesses interesting anti-caries properties while being compatible with oral epithelial cells.

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GC-TOF/MS-based metabolomics analysis to investigate the changes driven by N-Acetylcysteine in the plant-pathogen Xanthomonas citri subsp. citri

Scientific Reports ◽

10.1038/s41598-021-95113-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Simone Cristina Picchi ◽

Mariana de Souza e Silva ◽

Luiz Leonardo Saldanha ◽

Henrique Ferreira ◽

Marco Aurélio Takita ◽

...

Keyword(s):

Amino Acids ◽

Cell Proliferation ◽

Plant Pathogen ◽

Model Organism ◽

Citrus Canker ◽

Bacterial Cells ◽

Xanthomonas Citri ◽

Canker Disease ◽

Potential Use

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.

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Diversity Analysis of Endophytic Bacterial Community in Two Citrus Cultivars With Different Resistance to Citrus Canker

10.21203/rs.3.rs-347972/v1 ◽

2021 ◽

Author(s):

Bing Liu ◽

Jiahao Lai ◽

Simeng Wu ◽

Junxi Jiang ◽

Weigang Kuang

Keyword(s):

Bacterial Community ◽

Endophytic Bacteria ◽

Citrus Canker ◽

Navel Orange ◽

Xanthomonas Citri ◽

Canker Disease ◽

Satsuma Mandarin ◽

Endophytic Bacterial Community ◽

Dominant Bacteria ◽

The Relationship

Abstract The selective infection of Xanthomonas citri pv. citri to citrus cultivars is universally known, but it is not clarified whether there is a relationship between endophytic bacteria and the resistance of host variety to canker disease. In order to explore the relationship, Satsuma mandarin and Newhall navel orange were collected respectively as samples of resistant or susceptible cultivars to citrus canker disease, and endophytic bacterial community of two citrus cultivars were analyzed by using a next-generation, Illumina-based sequencing approach. Simultaneously, the seasonal dynamics of endophytic bacterial community and dominant genera were analyzed. The results showed that there were four dominant groups including Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes in all samples at phylum level. Endophytic bacteria were the most abundant in spring samples, then in summer and autumn samples. There were some differences between endophytic bacterial community of resistant citrus and that of susceptible citrus to canker disease, and the endophytic bacteria of Satsuma mandarin are more abundant than that of Newhall navel orange. According to the analysis of dominant bacteria in two citrus cultivars, it was found that some endophytic bacteria with antagonistic characteristics existed universally in all samples, although the dominant bacteria in different seasonal sample were different. However, in Newhall navel orange of susceptible citrus to canker disease, there were not only some bacteria against Xanthomonas citri pv. citri, but also some cooperative bacteria of canker occurrence like Stenotrophomonas.

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Evaluation of Saudi Fluorescent Pseudomonads Isolates as a Biocontrol Agent against Citrus Canker Disease Caused by Xanthomonas citri subsp citri A*

Egyptian Academic Journal of Biological Sciences G Microbiology ◽

10.21608/eajbsg.2014.16493 ◽

2014 ◽

Vol 6 (2) ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Mohammed Al-Saleh

Keyword(s):

Biocontrol Agent ◽

Citrus Canker ◽

Fluorescent Pseudomonads ◽

Xanthomonas Citri ◽

Canker Disease ◽

Citrus Canker Disease

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Biocontrol of Citrus Canker Disease Caused by Xanthomonas citri subsp. citri Using an Endophytic Bacillus thuringiensis

The Plant Pathology Journal ◽

10.5423/ppj.oa.03.2019.0060 ◽

2019 ◽

Vol 35 (5) ◽

pp. 486-497 ◽

Cited By ~ 4

Author(s):

Md. Nurul Islam ◽

Md. Sarafat Ali ◽

Seong-Jin Choi ◽

Jae-Wook Hyun ◽

Kwang-Hyun Baek

Keyword(s):

Bacillus Thuringiensis ◽

Citrus Canker ◽

Xanthomonas Citri ◽

Canker Disease ◽

Citrus Canker Disease

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Foliar Application of Limewash Improves Vegetative and Reproductive Growth and Fruit Quality of Bell Pepper under Deficit Irrigation

Journal of Horticultural Science & Technology ◽

10.46653/jhst190203069 ◽

2019 ◽

pp. 69-74

Author(s):

Hashim Hussain ◽

Ishfaq Ahmad Hafiz ◽

Touqeer Ahmad ◽

Irfan Ali ◽

Nadeem Akhtar Abbasi ◽

...

Keyword(s):

Foliar Application ◽

Bordeaux Mixture ◽

Citrus Canker ◽

Fruit Production ◽

Research Station ◽

Canker Disease ◽

Combined Application ◽

Vegetative And Reproductive Growth ◽

Horticultural Research

A good quality fruit fetches a high market value. Citrus canker disease badly affects quality of citrus fruits including grapefruit. The present study was conducted to find out suitable chemicals, alone or incombination, for the control of citrus canker. The experiment was conducted on 15-year-old disease-affected grapefruit cv. Shamber plants in the orchard of Horticultural Research Station, Sahiwal to control the disease for better quality fruit production. Therefore, four sprays of Aliette (300 g 100 L-1 of water), Bordeaux mixture (1:1:100), Flare (100 g 100 L-1 of water) or Bordeaux mixture + Flare were applied; two in the month of March and other two in the month of August with fifteen days interval along with control (no chemical). Combined application of Bordeaux mixture and Flare reduced the attack of citrus canker on leaves and fruits. Comparatively lower values of affected leaves (1.27%), lesions per leaf (0.40), affected fruits (0.25%) and lesions per fruit (0.22) were observed in the treatment in which a combination of Bordeaux mixture and Flare was sprayed on the plants. The disease percentage was high on leaves and fruits of unsprayed (control) plants, while other thee treatment were in the middle in their efficacy to control the disease.

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Survival of Xanthomonas citri in the bark tissues of citrus trees

Canadian Journal of Botany ◽

10.1139/b72-336 ◽

1972 ◽

Vol 50 (12) ◽

pp. 2629-2635 ◽

Cited By ~ 5

Author(s):

Masao Goto

Keyword(s):

High Frequency ◽

Citrus Canker ◽

Citrus Limon ◽

Xanthomonas Citri ◽

Bacterial Populations ◽

Large Numbers ◽

Adult Trees ◽

Infiltration Technique ◽

Lateral Branches ◽

Causal Bacterium

By leaf infiltration technique and by isolation method, the causal bacterium of citrus canker, Xanthomonas citri, was detected from discolored bark tissues of trunks, low scaffold limbs, and lateral branches of adult trees of lemon (Citrus limon, variety Lisbon), Natsudaidai (C. natsudaidai), and Unshu (C. unshu, variety Sugiyama). The pathogen was detected from 32% of the bark tissues taken from lemon trees, 15% from Natsudaidai, and 10% from Unshu. These isolation frequencies as well as the bacterial populations detected from the tissues correlated with degree of susceptibility of the twigs to citrus canker. Such discolored bark areas were considered to be the old canker lesions formed on the twigs in the seedling stage. In Unshu trees, the bacterium was also detected with high frequency but low populations from 6-month- to 3-year-old healthy-appearing green twigs, although any visible symptoms were not subsequently produced on them. In recovery experiments, large numbers of X. citri cells were isolated 3 years after inoculation, from the bark of the trunk of a 12-year-old lemon tree.

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