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Liu L, Liu X, Liu L, Zhu T, Ye R, Chen H, Zhou L, Wu G, Tan L, Han J, Li R, Ma X, Deng Z. Clarification of the infection pattern of Xanthomonas citri subsp. citri on citrus fruit by artificial inoculation. PLANT METHODS 2024; 20:65. [PMID: 38725004 PMCID: PMC11080196 DOI: 10.1186/s13007-024-01190-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/19/2024] [Indexed: 05/13/2024]
Abstract
BACKGROUND Citrus canker is a significant bacterial disease caused by Xanthomonas citri subsp. citri (Xcc) that severely impedes the healthy development of the citrus industry. Especially when citrus fruit is infected by Xcc, it will reduce or even lost its commercial value. However, due to the prolonged fruiting cycle and intricate structure, much less research progress had been made in canker disease on fruit than on leaf. In fact, limited understanding has been achieved on canker development and the response to Xcc infection in fruit. RESULTS Herein, the progression of canker disease on sweet orange fruit was tracked in the field. Results indicated that typical lesions initially appear on the sepal, style residue, nectary disk, epicarp, and peduncle of young fruits after petal fall. The susceptibility of fruits to Xcc infection diminished as the fruit developed, with no new lesions forming at the ripening stage. The establishment of an efficient method for inoculating Xcc on fruit as well as the artificial inoculation throughout the fruit's developmental cycle clarified this infection pattern. Additionally, microscopic observations during the infection process revealed that Xcc invasion caused structural changes on the surface and cross-section of the fruit. CONCLUSIONS An efficient system for inoculation on citrus fruit with Xcc was established, by which it can serve for the evaluation of citrus germplasm for canker disease resistance and systematic research on the interactions between Xcc and citrus fruits.
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Affiliation(s)
- Lian Liu
- National Center for Citrus Improvement-Changsha, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education, Changsha, 410128, China
| | - Xin Liu
- National Center for Citrus Improvement-Changsha, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education, Changsha, 410128, China
| | - Lingyi Liu
- National Center for Citrus Improvement-Changsha, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education, Changsha, 410128, China
| | - Tao Zhu
- National Center for Citrus Improvement-Changsha, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education, Changsha, 410128, China
| | - Rongchun Ye
- National Center for Citrus Improvement-Changsha, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education, Changsha, 410128, China
| | - Hao Chen
- National Center for Citrus Improvement-Changsha, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education, Changsha, 410128, China
| | - Linglei Zhou
- National Center for Citrus Improvement-Changsha, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education, Changsha, 410128, China
| | - Guang Wu
- National Center for Citrus Improvement-Changsha, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China
- Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education, Changsha, 410128, China
| | - Limei Tan
- Chenzhou Institute of Agricultural Science, Chenzhou, 423000, China
- NanLing Institute of Citrus Industry, Chenzhou, 423000, China
| | - Jian Han
- Hunan Academy of Agricultural Sciences, Hunan Horticultural Research Institute, Changsha, 410125, China
| | - Ronghua Li
- Comprehensive Experimental Station of Navel Sweet Orange in South Hunan, Chenzhou, 424200, China
| | - Xianfeng Ma
- National Center for Citrus Improvement-Changsha, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China.
- Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding, Ministry of Education, Changsha, 410128, China.
| | - Ziniu Deng
- National Center for Citrus Improvement-Changsha, College of Horticulture, Hunan Agricultural University, Changsha, 410128, China.
- NanLing Institute of Citrus Industry, Chenzhou, 423000, China.
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Kim YJ, Choi HS, Park DH. Persistence and viable but non-culturable state induced by streptomycin in Erwinia amylovora. Front Microbiol 2024; 15:1346300. [PMID: 38450169 PMCID: PMC10914980 DOI: 10.3389/fmicb.2024.1346300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 02/08/2024] [Indexed: 03/08/2024] Open
Abstract
Persister cell and viable but non-culturable (VBNC) state of bacteria are survival strategies against antibiotics and various environmental stresses, respectively, but they tend to be ignored in agriculture fields, even though bacteria can regain their abilities to survive and produce disease once those stresses disappear. This study was carried out to determine whether persister cell and VBNC state in Erwinia amylovora are present after exposures to streptomycin, the length of their persistence, and the steps needed to decrease the inoculum. Persister cells were observed using biphasic killed growth curve for 4-8 h when the late stationary phase cells of E. amylovora were cultured in liquid medium containing streptomycin. This state was maintained for up to 12 h based on the colony forming units (CFUs) of the colonies that grew on the mannitol glutamate yeast extract (MGY) medium after streptomycin was removed. The CFUs on the MGY medium were lower than the total count determined using the LIVE/DEAD Kit, suggesting that persister cells and VBNC state might co-exist for up to 12 h after exposure to streptomycin. However, after 12 h, E. amylovora cells did not continue to grow on the medium for 9 days, suggesting that they entered a VBNC state at that time and remained in a persistent state. In addition, based on the Redox Sensor Green staining method, the presence of both states was confirmed for up to 12 h, and only then did the VBNC state became apparent. Furthermore, persister cells were observed for up to 24 h, and damaged cells reduced when E. amylovora cells were culture in distilled water with streptomycin, indicating that the uptake of lower nutrients in E. amylovora led to prolonged persister cells and VBNC state, which are more likely to survive after streptomycin treatments. The addition of sucrose and oxytetracycline to distilled water containing streptomycin reduced persister cells than other sources did. Thus, to inhibit the spread of fire blight, management techniques must consider the hazards of using streptomycin treatments that induce dormancy, such as persister cells and VBNC state, beyond the development of resistant strain.
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Affiliation(s)
- Yeon Ju Kim
- Interdisciplinary Program in Smart Agriculture, Kangwon National University, Chuncheon-si, Republic of Korea
| | - Hyun Seo Choi
- Interdisciplinary Program in Smart Agriculture, Kangwon National University, Chuncheon-si, Republic of Korea
| | - Duck Hwan Park
- Interdisciplinary Program in Smart Agriculture, Kangwon National University, Chuncheon-si, Republic of Korea
- Plant Medicine Program, Division of Bioresource Sciences, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon-si, Republic of Korea
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Formation of Listeria monocytogenes persister cells in the produce-processing environment. Int J Food Microbiol 2023; 390:110106. [PMID: 36753793 DOI: 10.1016/j.ijfoodmicro.2023.110106] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/26/2022] [Accepted: 01/19/2023] [Indexed: 01/27/2023]
Abstract
Persisters are a subpopulation of growth-arrested cells that possess transient tolerance to lethal doses of antibiotics and can revert to an active state under the right conditions. Persister cells are considered as a public health concern. This study examined the formation of persisters by Listeria monocytogenes (LM) in an environment simulating a processing plant for leafy green production. Three LM strains isolated from California produce-processing plants and packinghouses with the strongest adherence abilities were used for this study. The impact of the cells' physiological status, density, and nutrient availability on the formation of persisters was also determined. Gentamicin at a dose of 100 mg/L was used for the isolation and screening of LM persisters. Results showed that the physiological status differences brought by culture preparation methods (plate-grown vs. broth-grown) did not impact persister formation (P > 0.05). Instead, higher persister ratios were found when cell density increased (P < 0.05). The formation of LM persister cells under simulated packinghouse conditions was tested by artificially inoculating stainless steel coupons with LM suspending in media with decreasing nutrient levels: brain heart infusion broth (1366 mg/L O2), produce-washing water with various organic loads (1332 mg/L O2 and 652 mg/L O2, respectively), as well as sterile Milli-Q water. LM survived in all suspensions at 4 °C with 85 % relative humidity for 7 days, with strain 483 producing the most persister cells (4.36 ± 0.294 Log CFU/coupon) on average. Although persister cell levels of LM 480 and 485 were reasonably steady in nutrient-rich media (i.e., BHI and HCOD), they declined in nutrient-poor media (i.e., LCOD and sterile Milli-Q water) over time. Persister populations decreased along with total viable cells, demonstrating the impact of available nutrients on the formation of persisters. The chlorine sensitivity of LM persister cells was evaluated and compared with regular LM cells. Results showed that, despite their increased tolerance to the antibiotic gentamicin, LM persisters were more susceptible to chlorine treatments (100 mg/L for 2 min) than regular cells.
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Costa J, Pothier JF, Boch J, Stefani E, Koebnik R. Integrating Science on Xanthomonas and Xylella for Integrated Plant Disease Management. Microorganisms 2022; 11:microorganisms11010006. [PMID: 36677298 PMCID: PMC9861534 DOI: 10.3390/microorganisms11010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 12/03/2022] [Indexed: 12/24/2022] Open
Abstract
Present, emerging or re-emerging plant diseases due to infection by bacteria of the Lysobacteraceae (syn: Xanthomonadaceae) family are continually challenging food security and cause significant losses to the economies of European countries each year [...].
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Affiliation(s)
- Joana Costa
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, 3000-456 Coimbra, Portugal
- Laboratory for Phytopathology, Instituto Pedro Nunes, 3030-199 Coimbra, Portugal
| | - Joël F. Pothier
- Environmental Genomics and Systems Biology Research Group, Institute of Natural Resource Sciences, Zurich University of Applied Sciences (ZHAW), 8820 Wädenswil, Switzerland
| | - Jens Boch
- Institute of Plant Genetics, Leibniz Universität Hannover, 30419 Hannover, Germany
| | - Emilio Stefani
- Department of Life Sciences, University of Modena and Reggio Emilia, 42122 Reggio Emilia, Italy
| | - Ralf Koebnik
- Plant Health Institute of Montpellier, University of Montpellier, CIRAD, INRAE, Institut Agro, IRD, 34394 Montpellier, France
- Correspondence: ; Tel.: +33-467-416228
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Green Synthesis of Silver Nanoparticles Using Euphorbia wallichii Leaf Extract: Its Antibacterial Action against Citrus Canker Causal Agent and Antioxidant Potential. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27113525. [PMID: 35684463 PMCID: PMC9182241 DOI: 10.3390/molecules27113525] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 11/24/2022]
Abstract
Biologically synthesized silver nanoparticles are emerging as attractive alternatives to chemical pesticides due to the ease of their synthesis, safety and antimicrobial activities in lower possible concentrations. In the present study, we have synthesized silver nanoparticles (AgNPs) using the aqueous extract of the medicinal plant Euphorbia wallichii and tested them against the plant pathogenic bacterium Xanthomonas axonopodis, the causative agent of citrus canker, via an in vitro experiment. The synthesized silver nanoparticles were characterized by techniques such as UV-Vis spectroscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis and transmission electron microscopy. Moreover, the plant species were investigated for phenolics, flavonoids and antioxidant activity. The antioxidant potential of the extract was determined against a DPPH radical. The extract was also evaluated for phenolic compounds using the HPLC technique. The results confirmed the synthesis of centered cubic, spherical-shaped and crystalline nanoparticles by employing standard characterization techniques. A qualitative and quantitative phytochemical analysis revealed the presence of phenolics (41.52 mg GAE/g), flavonoids (14.2 mg QE/g) and other metabolites of medicinal importance. Different concentrations (1000 µg/mL to 15.62 µg/mL—2 fold dilutions) of AgNPs and plant extract (PE) alone, and both in combination (AgNPs-PE), exhibited a differential inhibition of X. axanopodis in a high throughput antibacterial assay. Overall, AgNPs-PE was superior in terms of displaying significant antibacterial activity, followed by AgNPs alone. An appreciable antioxidant potential was recorded as well. The observed antibacterial and antioxidant potential may be attributed to eight phenolic compounds identified in the extract. The Euphorbia wallichii leaf-extract-induced synthesized AgNPs exhibited strong antibacterial activity against X. axanopodis, which could be exploited as effective alternative preparations against citrus canker in planta in a controlled environment. In addition, as a good source of phenolic compounds, the plant could be further exploited for potent antioxidants.
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Predicting the impact of environmental factors on citrus canker through multiple regression. PLoS One 2022; 17:e0260746. [PMID: 35381013 PMCID: PMC8982892 DOI: 10.1371/journal.pone.0260746] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 11/17/2021] [Indexed: 11/19/2022] Open
Abstract
Climatic conditions play a significant role in the development of citrus canker caused by Xanthomonas citri pv. citri (Xcc). Citrus canker is regarded as one of the major threats being faced by citrus industry in citrus growing countries of the world. Climatic factors exert significant impacts on growth stage, host susceptibility, succulence, vigor, survival, multiplication rate, pathogen dispersion, spore penetration rate, and spore germination. Predicting the impacts of climatic factors on these traits could aid in the development of effective management strategies against the disease. This study predicted the impacts of environmental variables, i.e., temperature, relative humidity, rainfall, and wind speed the development of citrus canker through multiple regression. These environmental variables were correlated with the development of canker on thirty (30) citrus varieties during 2017 to 2020. Significant positive correlations were noted among environment variables and disease development modeled through multiple regression model (Y = +24.02 + 0.5585 X1 + 0.2997 X2 + 0.3534 X3 + 3.590 X4 + 1.639 X5). Goodness of fit of the model was signified by coefficient determination value (97.5%). Results revealed the optimum values of environmental variables, i.e., maximum temperature (37°C), minimum temperature (27°C), relative humidity (55%), rainfall (4.7-7.1 mm) and wind speed (8 Km/h), which were conducive for the development of citrus canker. Current study would help researchers in designing better management strategies against citrus canker disease under changing climatic conditions in the future.
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Carvalho IGB, Merfa MV, Teixeira-Silva NS, Martins PMM, Takita MA, de Souza AA. Overexpression of mqsR in Xylella fastidiosa Leads to a Priming Effect of Cells to Copper Stress Tolerance. Front Microbiol 2021; 12:712564. [PMID: 34616378 PMCID: PMC8488296 DOI: 10.3389/fmicb.2021.712564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 08/09/2021] [Indexed: 12/13/2022] Open
Abstract
Copper-based compounds are widely used in agriculture as a chemical strategy to limit the spread of multiple plant diseases; however, the continuous use of this heavy metal has caused environmental damage as well as the development of copper-resistant strains. Thus, it is important to understand how the bacterial phytopathogens evolve to manage with this metal in the field. The MqsRA Toxin-Antitoxin system has been recently described for its function in biofilm formation and copper tolerance in Xylella fastidiosa, a plant-pathogen bacterium responsible for economic damage in several crops worldwide. Here we identified differentially regulated genes by X. fastidiosa MqsRA by assessing changes in global gene expression with and without copper. Results show that mqsR overexpression led to changes in the pattern of cell aggregation, culminating in a global phenotypic heterogeneity, indicative of persister cell formation. This phenotype was also observed in wild-type cells but only in the presence of copper. This suggests that MqsR regulates genes that alter cell behavior in order to prime them to respond to copper stress, which is supported by RNA-Seq analysis. To increase cellular tolerance, proteolysis and efflux pumps and regulator related to multidrug resistance are induced in the presence of copper, in an MqsR-independent response. In this study we show a network of genes modulated by MqsR that is associated with induction of persistence in X. fastidiosa. Persistence in plant-pathogenic bacteria is an important genetic tolerance mechanism still neglected for management of phytopathogens in agriculture, for which this work expands the current knowledge and opens new perspectives for studies aiming for a more efficient control in the field.
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Affiliation(s)
| | - Marcus Vinicius Merfa
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, United States
| | | | | | - Marco Aurélio Takita
- Centro de Citricultura Sylvio Moreira, Instituto Agronômico, Cordeirópolis, Brazil
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Bacteriophage-Mediated Control of Phytopathogenic Xanthomonads: A Promising Green Solution for the Future. Microorganisms 2021; 9:microorganisms9051056. [PMID: 34068401 PMCID: PMC8153558 DOI: 10.3390/microorganisms9051056] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/05/2021] [Accepted: 05/11/2021] [Indexed: 12/21/2022] Open
Abstract
Xanthomonads, members of the family Xanthomonadaceae, are economically important plant pathogenic bacteria responsible for infections of over 400 plant species. Bacteriophage-based biopesticides can provide an environmentally friendly, effective solution to control these bacteria. Bacteriophage-based biocontrol has important advantages over chemical pesticides, and treatment with these biopesticides is a minor intervention into the microflora. However, bacteriophages’ agricultural application has limitations rooted in these viruses’ biological properties as active substances. These disadvantageous features, together with the complicated registration process of bacteriophage-based biopesticides, means that there are few products available on the market. This review summarizes our knowledge of the Xanthomonas-host plant and bacteriophage-host bacterium interaction’s possible influence on bacteriophage-based biocontrol strategies and provides examples of greenhouse and field trials and products readily available in the EU and the USA. It also details the most important advantages and limitations of the agricultural application of bacteriophages. This paper also investigates the legal background and industrial property right issues of bacteriophage-based biopesticides. When appropriately applied, bacteriophages can provide a promising tool against xanthomonads, a possibility that is untapped. Information presented in this review aims to explore the potential of bacteriophage-based biopesticides in the control of xanthomonads in the future.
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