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Kong Y, Deering AJ, Nemali K. Minimizing Escherichia coli O157:H7 contamination in indoor farming: effects of cultivar type and ultra-violet light quality. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2024; 104:4218-4225. [PMID: 38294189 DOI: 10.1002/jsfa.13303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/31/2023] [Accepted: 01/07/2024] [Indexed: 02/01/2024]
Abstract
BACKGROUND Bacterial contamination of produce is a concern in indoor farming due to close plant spacing, recycling irrigation, warm temperatures, and high relative humidity during production. Cultivars that inherently resist contamination and photo-sanitization using ultraviolet (UV) radiation during the production phase can reduce bacterial contamination. However, there is limited information to support their use in indoor farming. RESULTS Lettuce (Lactuca sativa) cultivars with varying plant architectures grown in a custom-built indoor farm exhibited differences in E. coli O157:H7 survival after inoculation. The survival of E. coli O157:H7 was lowest in the leaf cultivar (open architecture) and highest in the romaine and oakleaf cultivars (compact architecture). Of the different UV wavelengths that were tested (UV-A, UV-A + B, UV-A + C), UV A + C at an intensity of 54.5 μmol m-2 s-1 (with 3.5 μmol m-2 s-1 of UV-C), provided for 15 min every day, was found to be most efficacious in reducing the E. coli O157:H7 survival on romaine lettuce with no negative effects on plant growth and quality. CONCLUSION Contamination of E. coli O157:H7 on lettuce plants can be reduced and the food safety levels in indoor farms can be increased by selecting cultivars with an open leaf architecture coupled with photo-sanitization using low and frequent exposure to UV A + C radiation. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Yuyao Kong
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN, USA
| | - Amanda J Deering
- Department of Food Science, Purdue University, West Lafayette, IN, USA
| | - Krishna Nemali
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN, USA
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2
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Szymańska S, Deja-Sikora E, Sikora M, Niedojadło K, Mazur J, Hrynkiewicz K. Colonization of Raphanus sativus by human pathogenic microorganisms. Front Microbiol 2024; 15:1296372. [PMID: 38426059 PMCID: PMC10902717 DOI: 10.3389/fmicb.2024.1296372] [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: 09/18/2023] [Accepted: 01/15/2024] [Indexed: 03/02/2024] Open
Abstract
Contamination of vegetables with human pathogenic microorganisms (HPMOs) is considered one of the most important problems in the food industry, as current nutritional guidelines include increased consumption of raw or minimally processed organic vegetables due to healthy lifestyle promotion. Vegetables are known to be potential vehicles for HPMOs and sources of disease outbreaks. In this study, we tested the susceptibility of radish (Raphanus sativus) to colonization by different HPMOs, including Escherichia coli PCM 2561, Salmonella enterica subsp. enterica PCM 2565, Listeria monocytogenes PCM 2191 and Bacillus cereus PCM 1948. We hypothesized that host plant roots containing bactericidal compounds are less prone to HPMO colonization than shoots and leaves. We also determined the effect of selected pathogens on radish growth to check host plant-microbe interactions. We found that one-week-old radish is susceptible to colonization by selected HPMOs, as the presence of the tested HPMOs was demonstrated in all organs of R. sativus. The differences were noticed 2 weeks after inoculation because B. cereus was most abundant in roots (log10 CFU - 2.54), S. enterica was observed exclusively in stems (log10 CFU - 3.15), and L. monocytogenes and E. coli were most abundant in leaves (log10 CFU - 4.80 and 3.23, respectively). The results suggest that E. coli and L. monocytogenes show a higher ability to colonize and move across the plant than B. cereus and S. enterica. Based on fluorescence in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) approach HPMOs were detected in extracellular matrix and in some individual cells of all analyzed organs. The presence of pathogens adversely affected the growth parameters of one-week-old R. sativus, especially leaf and stem fresh weight (decreased by 47-66 and 17-57%, respectively). In two-week-old plants, no reduction in plant biomass development was noted. This observation may result from plant adaptation to biotic stress caused by the presence of HPMOs, but confirmation of this assumption is needed. Among the investigated HPMOs, L. monocytogenes turned out to be the pathogen that most intensively colonized the aboveground part of R. sativus and at the same time negatively affected the largest number of radish growth parameters.
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Affiliation(s)
- Sonia Szymańska
- Department of Microbiology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, Toruń, Poland
| | - Edyta Deja-Sikora
- Department of Microbiology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, Toruń, Poland
| | - Marcin Sikora
- Center for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Toruń, Poland
| | - Katarzyna Niedojadło
- Department of Cellular and Molecular Biology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, Toruń, Poland
| | - Justyna Mazur
- Center for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Toruń, Poland
| | - Katarzyna Hrynkiewicz
- Department of Microbiology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, Toruń, Poland
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3
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Thomas GA, Paradell Gil T, Müller CT, Rogers HJ, Berger CN. From field to plate: How do bacterial enteric pathogens interact with ready-to-eat fruit and vegetables, causing disease outbreaks? Food Microbiol 2024; 117:104389. [PMID: 37919001 DOI: 10.1016/j.fm.2023.104389] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 09/11/2023] [Accepted: 09/17/2023] [Indexed: 11/04/2023]
Abstract
Ready-to-eat fruit and vegetables are a convenient source of nutrients and fibre for consumers, and are generally safe to eat, but are vulnerable to contamination with human enteric bacterial pathogens. Over the last decade, Salmonella spp., pathogenic Escherichia coli, and Listeria monocytogenes have been linked to most of the bacterial outbreaks of foodborne illness associated with fresh produce. The origins of these outbreaks have been traced to multiple sources of contamination from pre-harvest (soil, seeds, irrigation water, domestic and wild animal faecal matter) or post-harvest operations (storage, preparation and packaging). These pathogens have developed multiple processes for successful attachment, survival and colonization conferring them the ability to adapt to multiple environments. However, these processes differ across bacterial strains from the same species, and across different plant species or cultivars. In a competitive environment, additional risk factors are the plant microbiome phyllosphere and the plant responses; both factors directly modulate the survival of the pathogens on the leaf's surface. Understanding the mechanisms involved in bacterial attachment to, colonization of, and proliferation, on fresh produce and the role of the plant in resisting bacterial contamination is therefore crucial to reducing future outbreaks.
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Affiliation(s)
- Gareth A Thomas
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Teresa Paradell Gil
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Carsten T Müller
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Hilary J Rogers
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK
| | - Cedric N Berger
- School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX, UK.
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Totsline N, Kniel KE, Bais HP. Microgravity and evasion of plant innate immunity by human bacterial pathogens. NPJ Microgravity 2023; 9:71. [PMID: 37679341 PMCID: PMC10485020 DOI: 10.1038/s41526-023-00323-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 08/16/2023] [Indexed: 09/09/2023] Open
Abstract
Spaceflight microgravity and modeled-microgravity analogs (MMA) broadly alter gene expression and physiology in both pathogens and plants. Research elucidating plant and bacterial responses to normal gravity or microgravity has shown the involvement of both physiological and molecular mechanisms. Under true and simulated microgravity, plants display differential expression of pathogen-defense genes while human bacterial pathogens exhibit increased virulence, antibiotic resistance, stress tolerance, and reduced LD50 in animal hosts. Human bacterial pathogens including Salmonella enterica and E. coli act as cross-kingdom foodborne pathogens by evading and suppressing the innate immunity of plants for colonization of intracellular spaces. It is unknown if evasion and colonization of plants by human pathogens occurs under microgravity and if there is increased infection capability as demonstrated using animal hosts. Understanding the relationship between microgravity, plant immunity, and human pathogens could prevent potentially deadly outbreaks of foodborne disease during spaceflight. This review will summarize (1) alterations to the virulency of human pathogens under microgravity and MMA, (2) alterations to plant physiology and gene expression under microgravity and MMA, (3) suppression and evasion of plant immunity by human pathogens under normal gravity, (4) studies of plant-microbe interactions under microgravity and MMA. A conclusion suggests future study of interactions between plants and human pathogens under microgravity is beneficial to human safety, and an investment in humanity's long and short-term space travel goals.
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Affiliation(s)
- Noah Totsline
- Department of Plant and Soil Sciences, AP Biopharma, University of Delaware, Newark, DE, USA.
| | - Kalmia E Kniel
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, USA
| | - Harsh P Bais
- Department of Plant and Soil Sciences, AP Biopharma, University of Delaware, Newark, DE, USA
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5
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Antibacterial and Antibiofilm Effects of Allelopathic Compounds Identified in Medicago sativa L. Seedling Exudate against Escherichia coli. Molecules 2023; 28:molecules28062645. [PMID: 36985619 PMCID: PMC10056293 DOI: 10.3390/molecules28062645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 03/17/2023] Open
Abstract
In this study, the allelopathic properties of Medicago sativa L. (alfalfa) seedling exudates on the germination of seeds of various species were investigated. The compounds responsible for the allelopathic effects of alfalfa were identified and characterized by employing liquid chromatography ion mobility high-resolution mass spectrometry. Crude exudates inhibited the germination of seeds of all various plant species tested. Overall, nine compounds in alfalfa were identified and quantified. The most predominant compounds were a hyperoside representing a flavonoid glucoside, the non-proteinogenic amino acid canavanine, and two dipeptides, identified as H-Glu-Tyr-OH and H-Phe-Glu-OH. The latter corresponds to the first finding that dipeptides are exuded from alfalfa seedlings. In addition, the antibacterial and antibiofilm activities of alfalfa exudate and its identified compounds were elucidated. Both hyperoside and canavanine revealed the best antibacterial activity with minimum inhibitory concentration (MIC) values that ranged from 8 to 32 and 32 to 256 µg/mL, respectively. Regarding the antibiofilm action, hyperoside and canavanine caused a decline in the percentage of E. coli isolates that possessed a strong and moderate biofilm-forming potential from 68.42% to 21.05% and 31.58%, respectively. Studies on their inhibiting effects exhibit that these major substances are predominantly responsible for the allelopathic and antimicrobial effects of the crude exudates.
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Foliar Roughness and Water Content Impact on Escherichia coli Attachment in Baby Leafy Greens. BIOLOGY 2023; 12:biology12010102. [PMID: 36671794 PMCID: PMC9855646 DOI: 10.3390/biology12010102] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/03/2023] [Accepted: 01/04/2023] [Indexed: 01/12/2023]
Abstract
Understanding the relation between the susceptibility of different leafy greens to human pathogen contamination and leaf traits can contribute to increase the food safety of the fresh vegetable industry. The aim of this research was to evaluate the susceptibility to E. coli ATCC 35218 attachment in 30 accessions of baby leaves, and to identify leaf traits potentially involved in the contamination. The accessions were surface inoculated with a bacterial suspension containing 1 × 107 cells/mL and the attachment was measured 1.5 h after inoculation. Significant differences in attachment were detected between the accessions for p ≤ 0.05. The three most and the three least susceptible accessions were selected and characterized for leaf micro-morphological traits (stomata density and size, surface roughness) and water content. Scanning electron microscopy was used to analyse the stomatal parameters. Roughness was measured by an innovative portable 3D digital microscope. No significant correlation between the attachment of E. coli ATCC 35218 and stomatal parameters was detected, while the attachment was positively correlated with roughness and water content. The E. coli ATCC 35218 population in surface-inoculated leaves was also measured after a UV treatment, which was found to be less effective in reducing bacterial contamination in the rougher leaves. This result suggested that roughness offers UV protection, further highlighting its impact on the microbiological safety of baby leafy greens.
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Melo J, Quintas C. Minimally processed fruits as vehicles for foodborne pathogens. AIMS Microbiol 2023; 9:1-19. [PMID: 36891538 PMCID: PMC9988415 DOI: 10.3934/microbiol.2023001] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 12/21/2022] [Accepted: 01/04/2023] [Indexed: 01/18/2023] Open
Abstract
The consumption of minimally processed fruit (MPF) has increased over the last decade due to a novel trend in the food market along with the raising consumers demand for fresh, organic, convenient foods and the search for healthier lifestyles. Although represented by one of the most expanded sectors in recent years, the microbiological safety of MPF and its role as an emergent foodborne vehicle has caused great concern to the food industry and public health authorities. Such food products may expose consumers to a risk of foodborne infection as they are not subjected to prior microbial lethal methods to ensure the removal or destruction of pathogens before consumption. A considerable number of foodborne disease cases linked to MPF have been reported and pathogenic strains of Salmonella enterica, Escherichia coli, Listeria monocytogenes, as well as Norovirus accounted for the majority of cases. Microbial spoilage is also an issue of concern as it may result in huge economic losses among the various stakeholders involved in the manufacturing and commercialization of MPF. Contamination can take place at any step of production/manufacturing and identifying the nature and sources of microbial growth in the farm-to-fork chain is crucial to ensure appropriate handling practices for producers, retailers, and consumers. This review aims to summarize information about the microbiological hazards associated with the consumption of MPF and also highlight the importance of establishing effective control measures and developing coordinated strategies in order to enhance their safety.
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Affiliation(s)
- Jessie Melo
- Universidade do Algarve, Instituto Superior de Engenharia, Campus da Penha 8005-139, Faro Portugal and MED, Mediterranean Institute for Agriculture, Environment and Development, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Célia Quintas
- Universidade do Algarve, Instituto Superior de Engenharia, Campus da Penha 8005-139, Faro Portugal and MED, Mediterranean Institute for Agriculture, Environment and Development, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
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8
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Jacob C, Velásquez AC, Josh NA, Settles M, He SY, Melotto M. Dual transcriptomic analysis reveals metabolic changes associated with differential persistence of human pathogenic bacteria in leaves of Arabidopsis and lettuce. G3 (BETHESDA, MD.) 2021; 11:jkab331. [PMID: 34550367 PMCID: PMC8664426 DOI: 10.1093/g3journal/jkab331] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 09/09/2021] [Indexed: 11/14/2022]
Abstract
Understanding the molecular determinants underlying the interaction between the leaf and human pathogenic bacteria is key to provide the foundation to develop science-based strategies to prevent or decrease the pathogen contamination of leafy greens. In this study, we conducted a dual RNA-sequencing analysis to simultaneously define changes in the transcriptomic profiles of the plant and the bacterium when they come in contact. We used an economically relevant vegetable crop, lettuce (Lactuca sativa L. cultivar Salinas), and a model plant, Arabidopsis thaliana Col-0, as well as two pathogenic bacterial strains that cause disease outbreaks associated with fresh produce, Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium 14028s (STm 14028s). We observed commonalities and specificities in the modulation of biological processes between Arabidopsis and lettuce and between O157:H7 and STm 14028s during early stages of the interaction. We detected a larger alteration of gene expression at the whole transcriptome level in lettuce and Arabidopsis at 24 h post inoculation with STm 14028s compared to that with O157:H7. In addition, bacterial transcriptomic adjustments were substantially larger in Arabidopsis than in lettuce. Bacterial transcriptome was affected at a larger extent in the first 4 h compared to the subsequent 20 h after inoculation. Overall, we gained valuable knowledge about the responses and counter-responses of both bacterial pathogen and plant host when these bacteria are residing in the leaf intercellular space. These findings and the public genomic resources generated in this study are valuable for additional data mining.
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Affiliation(s)
- Cristián Jacob
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
- Department of Plant Sciences, Horticulture and Agronomy Graduate Group, University of California, Davis, Davis, CA 95616, USA
- Departamento de Ciencias Vegetales, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
| | - André C Velásquez
- Department of Biology, Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA
| | - Nikhil A Josh
- Bioinformatics Core Facility in the Genome Center, University of California, Davis, Davis, CA 95616, USA
| | - Matthew Settles
- Bioinformatics Core Facility in the Genome Center, University of California, Davis, Davis, CA 95616, USA
| | - Sheng Yang He
- Department of Biology, Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
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9
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George AS, Brandl MT. Plant Bioactive Compounds as an Intrinsic and Sustainable Tool to Enhance the Microbial Safety of Crops. Microorganisms 2021; 9:2485. [PMID: 34946087 PMCID: PMC8704493 DOI: 10.3390/microorganisms9122485] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/20/2021] [Accepted: 11/26/2021] [Indexed: 12/25/2022] Open
Abstract
Outbreaks of produce-associated foodborne illness continue to pose a threat to human health worldwide. New approaches are necessary to improve produce safety. Plant innate immunity has potential as a host-based strategy for the deactivation of enteric pathogens. In response to various biotic and abiotic threats, plants mount defense responses that are governed by signaling pathways. Once activated, these result in the release of reactive oxygen and nitrogen species in addition to secondary metabolites that aim at tempering microbial infection and pest attack. These phytochemicals have been investigated as alternatives to chemical sanitization, as many are effective antimicrobial compounds in vitro. Their antagonistic activity toward enteric pathogens may also provide an intrinsic hurdle to their viability and multiplication in planta. Plants can detect and mount basal defenses against enteric pathogens. Evidence supports the role of plant bioactive compounds in the physiology of Salmonella enterica, Escherichia coli, and Listeria monocytogenes as well as their fitness on plants. Here, we review the current state of knowledge of the effect of phytochemicals on enteric pathogens and their colonization of plants. Further understanding of the interplay between foodborne pathogens and the chemical environment on/in host plants may have lasting impacts on crop management for enhanced microbial safety through translational applications in plant breeding, editing technologies, and defense priming.
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Affiliation(s)
| | - Maria T. Brandl
- Produce Safety and Microbiology Research Unit, United States Department of Agriculture, Agricultural Research Service, Albany, CA 94710, USA;
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Chalupowicz L, Manulis-Sasson S, Barash I, Elad Y, Rav-David D, Brandl MT. Effect of Plant Systemic Resistance Elicited by Biological and Chemical Inducers on the Colonization of the Lettuce and Basil Leaf Apoplast by Salmonella enterica. Appl Environ Microbiol 2021; 87:e0115121. [PMID: 34613760 PMCID: PMC8612278 DOI: 10.1128/aem.01151-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 09/28/2021] [Indexed: 11/20/2022] Open
Abstract
Mitigation strategies to prevent microbial contamination of crops are lacking. We tested the hypothesis that induction of plant systemic resistance by biological (induced systemic resistance [ISR]) and chemical (systemic acquired resistance [SAR]) elicitors reduces endophytic colonization of leaves by Salmonella enterica serovars Senftenberg and Typhimurium. S. Senftenberg had greater endophytic fitness than S. Typhimurium in basil and lettuce. The apoplastic population sizes of serovars Senftenberg and Typhimurium in basil and lettuce, respectively, were significantly reduced approximately 10- to 100-fold by root treatment with microbial inducers of systemic resistance compared to H2O treatment. Rhodotorula glutinis effected the lowest population increases of S. Typhimurium in lettuce and S. Senftenberg in basil leaves, respectively 120- and 60-fold lower than those seen with the H2O treatment over 10 days postinoculation. Trichoderma harzianum and Pichia guilliermondii did not have any significant effect on S. Senftenberg in the basil apoplast. The chemical elicitors acidobenzolar-S-methyl and dl-β-amino-butyric acid inhibited S. Typhimurium multiplication in the lettuce apoplast 10- and 2-fold, respectively, compared to H2O-treated plants. All ISR and SAR inducers applied to lettuce roots in this study increased leaf expression of the defense gene PR1, as did Salmonella apoplastic colonization in H2O-treated lettuce plants. Remarkably, both acidobenzolar-S-methyl upregulation and R. glutinis upregulation of PR1 were repressed by the presence of Salmonella in the leaves. However, enhanced PR1 expression was sustained longer and at greater levels upon elicitor treatment than by Salmonella induction alone. These results serve as a proof of concept that priming of plant immunity may provide an intrinsic hurdle against the endophytic establishment of enteric pathogens in leafy vegetables. IMPORTANCE Fruit and vegetables consumed raw have become an important vehicle of foodborne illness despite a continuous effort to improve their microbial safety. Salmonella enterica has caused numerous recalls and outbreaks of infection associated with contaminated leafy vegetables. Evidence is increasing that enteric pathogens can reach the leaf apoplast, where they confront plant innate immunity. Plants may be triggered for induction of their defense signaling pathways by exposure to chemical or microbial elicitors. This priming for recognition of microbes by plant defense pathways has been used to inhibit plant pathogens and limit disease. Given that current mitigation strategies are insufficient in preventing microbial contamination of produce and associated outbreaks, we investigated the effect of plant-induced resistance on S. enterica colonization of the lettuce and basil leaf apoplast in order to gain a proof of concept for the use of such an intrinsic approach to inhibit human pathogens in leafy vegetables.
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Affiliation(s)
- L. Chalupowicz
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Institute, Rishon LeZion, Israel
| | - S. Manulis-Sasson
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Institute, Rishon LeZion, Israel
| | - I. Barash
- Department of Molecular Biology and Ecology of Plants, Faculty of Life Sciences, University of Tel Aviv, Tel-Aviv, Israel
| | - Y. Elad
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Institute, Rishon LeZion, Israel
| | - D. Rav-David
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Institute, Rishon LeZion, Israel
| | - M. T. Brandl
- Produce Safety and Microbiology Research Unit, USDA, Agricultural Research Service, Albany, California, USA
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11
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Truong H, Garmyn D, Gal L, Fournier C, Sevellec Y, Jeandroz S, Piveteau P. Plants as a realized niche for Listeria monocytogenes. Microbiologyopen 2021; 10:e1255. [PMID: 34964288 PMCID: PMC8710918 DOI: 10.1002/mbo3.1255] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/09/2021] [Accepted: 11/18/2021] [Indexed: 12/27/2022] Open
Abstract
Listeria monocytogenes is a human pathogen. It is the causative agent of listeriosis, the leading cause of bacterial-linked foodborne mortality in Europe and elsewhere. Outbreaks of listeriosis have been associated with the consumption of fresh produce including vegetables and fruits. In this review we summarize current data providing direct or indirect evidence that plants can serve as habitat for L. monocytogenes, enabling this human pathogen to survive and grow. The current knowledge of the mechanisms involved in the interaction of this bacterium with plants is addressed, and whether this foodborne pathogen elicits an immune response in plants is discussed.
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Affiliation(s)
- Hoai‐Nam Truong
- Agroécologie, AgroSup Dijon, CNRS, INRAEUniversity Bourgogne Franche‐ComtéDijonFrance
| | - Dominique Garmyn
- Agroécologie, AgroSup Dijon, CNRS, INRAEUniversity Bourgogne Franche‐ComtéDijonFrance
| | - Laurent Gal
- Agroécologie, AgroSup Dijon, CNRS, INRAEUniversity Bourgogne Franche‐ComtéDijonFrance
| | - Carine Fournier
- Agroécologie, AgroSup Dijon, CNRS, INRAEUniversity Bourgogne Franche‐ComtéDijonFrance
| | - Yann Sevellec
- French Agency for Food, Environmental and Occupational Health & Safety (ANSES), Laboratory for Food Safety, Salmonella and Listeria UnitParis‐Est UniversityMaisons‐AlfortCedexFrance
| | - Sylvain Jeandroz
- Agroécologie, AgroSup Dijon, CNRS, INRAEUniversity Bourgogne Franche‐ComtéDijonFrance
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Identification of a Chitooligosaccharide Mechanism against Bacterial Leaf Blight on Rice by In Vitro and In Silico Studies. Int J Mol Sci 2021; 22:ijms22157990. [PMID: 34360756 PMCID: PMC8347687 DOI: 10.3390/ijms22157990] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/14/2021] [Accepted: 07/18/2021] [Indexed: 12/12/2022] Open
Abstract
This study focuses on a commercial plant elicitor based on chitooligosaccharides (BIG®), which aids in rice plant growth and disease resistance to bacterial leaf blight (BLB). When the pathogen (Xoo) vigorously attacks rice that has suffered yield losses, it can cause damage in up to 20% of the plant. Furthermore, Xoo is a seed-borne pathogen that can survive in rice seeds for an extended period. In this study, when rice seeds were soaked and sprayed with BIG®, there was a significant increase in shoot and root length, as well as plant biomass. Furthermore, BIG®-treated rice plants showed a significant reduction in BLB severity of more than 33%. Synchrotron radiation-based Fourier transform infrared (SR-FTIR) analysis was used to characterize BIG®’s mechanism in the chemical structure of rice leaves. The SR-FTIR results at 1650, 1735, and 1114 cm−1 indicated changes in biochemical components such as pectins, lignins, proteins, and celluloses. These findings demonstrated that commercial BIG® not only increased rice growth but also induced resistance to BLB. The drug’s target enzyme, Xoo 1075 from Xanthomonas oryzae (PDB ID: 5CY8), was analyzed for its interactions with polymer ingredients, specifically chitooligosaccharides, to gain molecular insights down to the atomic level. The results are intriguing, with a strong binding of the chitooligosaccharide polymer with the drug target, revealing 10 hydrogen bonds between the protein and polymer. Overall, the computational analysis supported the experimentally demonstrated strong binding of chitooligosaccharides to the drug target.
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Zarkani AA, Schikora A. Mechanisms adopted by Salmonella to colonize plant hosts. Food Microbiol 2021; 99:103833. [PMID: 34119117 DOI: 10.1016/j.fm.2021.103833] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 11/16/2022]
Abstract
Fruits and vegetables consumed fresh or as minimally-processed produce, have multiple benefits for our diet. Unfortunately, they bring a risk of food-borne diseases, for example salmonellosis. Interactions between Salmonella and crop plants are indeed a raising concern for the global health. Salmonella uses multiple strategies to manipulate the host defense system, including plant's defense responses. The main focus of this review are strategies used by this bacterium during the interaction with crop plants. Emphasis was put on how Salmonella avoids the plant defense responses and successfully colonizes plants. In addition, several factors were reviewed assessing their impact on Salmonella persistence and physiological adaptation to plants and plant-related environment. The understanding of those mechanisms, their regulation and use by the pathogen, while in contact with plants, has significant implication on the growth, harvest and processing steps in plant production system. Consequently, it requires both the authorities and science to advance and definite methods aiming at prevention of crop plants contamination. Thus, minimizing and/or eliminating the potential of human diseases.
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Affiliation(s)
- Azhar A Zarkani
- Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104, Braunschweig, Germany; University of Baghdad, Department of Biotechnology, 10071, Baghdad, Iraq.
| | - Adam Schikora
- Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Messeweg 11/12, 38104, Braunschweig, Germany.
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14
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Pang Z, Zhang L, Coaker G, Ma W, He SY, Wang N. Citrus CsACD2 Is a Target of Candidatus Liberibacter Asiaticus in Huanglongbing Disease. PLANT PHYSIOLOGY 2020; 184:792-805. [PMID: 32759268 PMCID: PMC7536665 DOI: 10.1104/pp.20.00348] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 07/27/2020] [Indexed: 05/06/2023]
Abstract
Citrus Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus (Las), is one of the most destructive citrus diseases worldwide, yet how Las causes HLB is poorly understood. Here we show that a Las-secreted protein, SDE15 (CLIBASIA_04025), suppresses plant immunity and promotes Las multiplication. Transgenic expression of SDE15 in Duncan grapefruit (Citrus × paradisi) suppresses the hypersensitive response induced by Xanthomonas citri ssp. citri (Xcc) and reduces the expression of immunity-related genes. SDE15 also suppresses the hypersensitive response triggered by the Xanthomonas vesicatoria effector protein AvrBsT in Nicotiana benthamiana, suggesting that it may be a broad-spectrum suppressor of plant immunity. SDE15 interacts with the citrus protein CsACD2, a homolog of Arabidopsis (Arabidopsis thaliana) ACCELERATED CELL DEATH 2 (ACD2). SDE15 suppression of plant immunity is dependent on CsACD2, and overexpression of CsACD2 in citrus suppresses plant immunity and promotes Las multiplication, phenocopying overexpression of SDE15. Identification of CsACD2 as a susceptibility target has implications in genome editing for novel plant resistance against devastating HLB.
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Affiliation(s)
- Zhiqian Pang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida/Institute of Food and Agricultural Sciences, Lake Alfred, Florida 33850
| | - Li Zhang
- MSU-DOE Plant Research Laboratory, Plant Resilient Institute, Michigan State University, East Lansing, Michigan 48824
- Howard Hughes Medical Institute, Michigan State University, East Lansing, Michigan 48824
| | - Gitta Coaker
- Department of Plant Pathology, University of California, Davis, Davis, California 95616
| | - Wenbo Ma
- Department of Microbiology and Plant Pathology, University of California, Riverside, Riverside, California 92521
| | - Sheng-Yang He
- MSU-DOE Plant Research Laboratory, Plant Resilient Institute, Michigan State University, East Lansing, Michigan 48824
- Howard Hughes Medical Institute, Michigan State University, East Lansing, Michigan 48824
| | - Nian Wang
- Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida/Institute of Food and Agricultural Sciences, Lake Alfred, Florida 33850
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Oblessuc PR, Melotto M. A Simple Assay to Assess Salmonella enterica Persistence in Lettuce Leaves After Low Inoculation Dose. Front Microbiol 2020; 11:1516. [PMID: 32765443 PMCID: PMC7381196 DOI: 10.3389/fmicb.2020.01516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 06/10/2020] [Indexed: 11/17/2022] Open
Abstract
Salmonella enterica is an enterobacterium associated with numerous foodborne illnesses worldwide. Leafy greens have been a common vehicle for disease outbreaks caused by S. enterica. This human pathogen can be introduced into crop fields and potentially contaminate fresh produce. Several studies have shown that S. enterica can survive for long periods in the plant tissues. Often, S. enterica population does not reach high titers in leaves; however, it is still relevant for food safety due to the low infective dose of the pathogen. Thus, laboratory procedures to study the survival of S. enterica in fresh vegetables should be adjusted accordingly. Here, we describe a protocol to assess the population dynamics of S. enterica serovar Typhimurium 14028s in the leaf apoplast of three cultivars of lettuce (Lactuca sativa L.). By comparing a range of inoculum concentrations, we showed that vacuum infiltration of a bacterium inoculum level in the range of 3.4 Log CFU ml–1 (with a recovery of approximately 170 cells per gram of fresh leaves 2 h post inoculation) allows for a robust assessment of bacterial persistence in three lettuce cultivars using serial dilution plating and qPCR methods. We anticipate that this method can be applied to other leaf–human pathogen combinations in an attempt to standardize the procedure for future efforts to screen for plant phenotypic variability, which is useful for breeding programs.
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Affiliation(s)
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
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16
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Ranjbaran M, Solhtalab M, Datta AK. Mechanistic modeling of light-induced chemotactic infiltration of bacteria into leaf stomata. PLoS Comput Biol 2020; 16:e1007841. [PMID: 32384085 PMCID: PMC7209104 DOI: 10.1371/journal.pcbi.1007841] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 04/02/2020] [Indexed: 12/04/2022] Open
Abstract
Light is one of the factors that can play a role in bacterial infiltration into leafy greens by keeping stomata open and providing photosynthetic products for microorganisms. We model chemotactic transport of bacteria within a leaf tissue in response to photosynthesis occurring within plant mesophyll. The model includes transport of carbon dioxide, oxygen, bicarbonate, sucrose/glucose, bacteria, and autoinducer-2 within the leaf tissue. Biological processes of carbon fixation in chloroplasts, and respiration in mitochondria of the plant cells, as well as motility, chemotaxis, nutrient consumption and communication in the bacterial community are considered. We show that presence of light is enough to boost bacterial chemotaxis through the stomatal opening and toward photosynthetic products within the leaf tissue. Bacterial chemotactic ability is a major player in infiltration, and plant stomatal defense in closing the stomata as a perception of microbe-associated molecular patterns is an effective way to inhibit the infiltration. Exposure to light can trigger photosynthesis in plant leaves, such as leafy-greens, and increase concentrations of photosynthetic products, such as glucose, within the leaf tissue. Bacteria existing at the leaf surfaces may respond to the available photosynthetic products and migrate into the leaf tissue by chemotaxis toward nutrient concentration gradients. Once the bacteria are inside the leaf tissue, they cannot be washed away, presenting a risk to the consumer. Here, a physics-based model for this light-driven infiltration is presented. This mechanistic model couples transport of bacteria and nutrients, and photosynthesis within a leaf tissue around one stomatal opening. The model shows that the ability of bacteria to transport via chemotaxis is a major factor in infiltration. A moderate intensity light is sufficient to promote chemotactic infiltration of bacteria on a leaf surface into its interior. Infiltration is enhanced in the presence of blue, white and red lights, and for a larger stomatal aperture.
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Affiliation(s)
- Mohsen Ranjbaran
- Department of Biological and Environmental Engineering, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, United States of America
| | - Mina Solhtalab
- Department of Biological and Environmental Engineering, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, United States of America
- Department of Civil and Environmental Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Illinois, United States of America
| | - Ashim K. Datta
- Department of Biological and Environmental Engineering, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, United States of America
- * E-mail:
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Schierstaedt J, Grosch R, Schikora A. Agricultural production systems can serve as reservoir for human pathogens. FEMS Microbiol Lett 2020; 366:5715908. [PMID: 31981360 DOI: 10.1093/femsle/fnaa016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 01/21/2020] [Indexed: 12/31/2022] Open
Abstract
Food-borne diseases are a threat to human health and can cause severe economic losses. Nowadays, in a growing and increasingly interconnected world, food-borne diseases need to be dealt with in a global manner. In order to tackle this issue, it is essential to consider all possible entry routes of human pathogens into the production chain. Besides the post-harvest handling of the fresh produce itself, also the prevention of contamination in livestock and agricultural soils are of particular importance. While the monitoring of human pathogens and intervening measures are relatively easy to apply in livestock and post-harvest, the investigation of the prevention strategies in crop fields is a challenging task. Furthermore, crop fields are interconnected with livestock via fertilizers and feed; therefore, a poor hygiene management can cause cross-contamination. In this review, we highlight the possible contamination of crop plants by bacterial human pathogens via the rhizosphere, their interaction with the plant and possible intervention strategies. Furthermore, we discuss critical issues and questions that are still open.
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Affiliation(s)
- Jasper Schierstaedt
- Plant-Microbe Systems, Leibniz Institute of Vegetable and Ornamental Crops, 14979 Großbeeren, Germany
| | - Rita Grosch
- Plant-Microbe Systems, Leibniz Institute of Vegetable and Ornamental Crops, 14979 Großbeeren, Germany
| | - Adam Schikora
- Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, 38104 Braunschweig, Germany
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Jacob C, Melotto M. Human Pathogen Colonization of Lettuce Dependent Upon Plant Genotype and Defense Response Activation. FRONTIERS IN PLANT SCIENCE 2020; 10:1769. [PMID: 32082340 PMCID: PMC7002439 DOI: 10.3389/fpls.2019.01769] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 12/18/2019] [Indexed: 05/26/2023]
Abstract
Fresh produce contaminated with human pathogens may result in foodborne disease outbreaks that cause a significant number of illnesses, hospitalizations, and death episodes affecting both public health and the agribusiness every year. The ability of these pathogens to survive throughout the food production chain is remarkable. Using a genetic approach, we observed that leaf colonization by Salmonella enterica serovar Typhimurium 14028s (S. Typhimurium 14028s) and Escherichia coli O157:H7 was significantly affected by genetic diversity of lettuce (Lactuca sativa L. and L. serriola L.). In particular, there was a significant variation among 11 lettuce genotypes in bacterial attachment, internalization, and apoplastic persistence after surface- and syringe-inoculation methods. We observed a significant correlation of the bacterial leaf internalization rate with stomatal pore traits (width and area). Moreover, bacterial apoplastic populations significantly decreased in 9 out of 11 lettuce genotypes after 10 days of surface inoculation. However, after syringe infiltration, populations of E. coli O157:H7 and S. Typhimurium 14028s showed positive, neutral, or negative net growth in a 10-day experimental period among seedlings of different lettuce types. The relative ability of the bacteria to persist in the apoplast of lettuce genotypes after syringe inoculation was minimally altered when assessed during a longer period (20 days) using 3.5- to 4-week-old plants. Interestingly, contrasting bacterial persistence in the lettuce genotypes Red Tide and Lollo Rossa was positively correlated with significant differences in the level of reactive oxygen species burst and callose deposition against S. Typhimurium 14028s and E. coli O157:H7 which are related to plant defense responses. Overall, we characterized the genetic diversity in the interaction between lettuce genotypes and enterobacteria S. Typhimurium 14028s and E. coli O157:H7 and discovered that this genetic diversity is linked to variations in plant immune responses towards these bacteria. These results provide opportunities to capitalize on plant genetics to reduce pathogen contamination of leaves.
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Affiliation(s)
- Cristián Jacob
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
- Horticulture and Agronomy Graduate Group, University of California, Davis, Davis, CA, United States
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
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19
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Montano J, Rossidivito G, Torreano J, Porwollik S, Sela Saldinger S, McClelland M, Melotto M. Salmonella enterica Serovar Typhimurium 14028s Genomic Regions Required for Colonization of Lettuce Leaves. Front Microbiol 2020; 11:6. [PMID: 32038592 PMCID: PMC6993584 DOI: 10.3389/fmicb.2020.00006] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 01/03/2020] [Indexed: 11/24/2022] Open
Abstract
Contamination of edible produce leaves with human bacterial pathogens has been associated with serious disease outbreaks and has become a major public health concern affecting all aspects of the market, from farmers to consumers. While pathogen populations residing on the surface of ready-to-eat produce can be potentially removed through thorough washing, there is no disinfection technology available that effectively eliminates internal bacterial populations. By screening 303 multi-gene deletion (MGD) mutants of Salmonella enterica serovar Typhimurium (STm) 14028s, we were able to identify ten genomic regions that play a role in opening the stomatal pore of lettuce leaves. The major metabolic functions of the deleted regions are associated with sensing the environment, bacterium movement, transport through the bacterial membrane, and biosynthesis of surface appendages. Interestingly, at 21 days post inoculation, seven of these mutants showed increased population titers inside the leaf, two mutants showed similar titers as the wild type bacterium, whereas one mutant with a large deletion that includes the Salmonella pathogenicity island 2 (SPI-2) showed significantly impaired persistence in the leaf apoplast. These findings suggest that not all the genomic regions required for initiation of leaf colonization (i.e., epiphytic behavior and tissue penetration) are essential for continuing bacterial survival as an endophyte. We also observed that mutants lacking either SPI-1 (Mut3) or SPI-2 (Mut9) induce callose deposition levels comparable to those of the wild type STm 14028s; therefore, these islands do not seem to affect this lettuce defense mechanism. However, the growth of Mut9, but not Mut3, was significantly impaired in the leaf apoplastic wash fluid (AWF) suggesting that the STm persistence in the apoplast may be linked to nutrient acquisition capabilities or overall bacterial fitness in this niche, which are dependent on the gene(s) deleted in the Mut9 strain. The genetic basis of STm colonization of leaves investigated in this study provides a foundation from which to develop mitigation tactics to enhance food safety.
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Affiliation(s)
- Jeanine Montano
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
- Plant Pathology Graduate Group, University of California, Davis, Davis, CA, United States
| | - Gabrielle Rossidivito
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
- Plant Biology Graduate Group, University of California, Davis, Davis, CA, United States
| | - Joseph Torreano
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
| | - Steffen Porwollik
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA, United States
| | - Shlomo Sela Saldinger
- Microbial Food Safety Research Unit, Department of Food Science, Agricultural Research Organization, Volcani Center, Rishon LeTsiyon, Israel
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA, United States
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
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20
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Oblessuc PR, Matiolli CC, Melotto M. Novel molecular components involved in callose-mediated Arabidopsis defense against Salmonella enterica and Escherichia coli O157:H7. BMC PLANT BIOLOGY 2020; 20:16. [PMID: 31914927 PMCID: PMC6950905 DOI: 10.1186/s12870-019-2232-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 12/30/2019] [Indexed: 05/26/2023]
Abstract
BACKGROUND Food contamination with Salmonella enterica and enterohemorrhagic Escherichia coli is among the leading causes of foodborne illnesses worldwide and crop plants are associated with > 50% of the disease outbreaks. However, the mechanisms underlying the interaction of these human pathogens with plants remain elusive. In this study, we have explored plant resistance mechanisms against these enterobacteria and the plant pathogen Pseudomonas syringae pv. tomato (Pst) DC3118, as an opportunity to improve food safety. RESULTS We found that S. enterica serovar Typhimurium (STm) transcriptionally modulates stress responses in Arabidopsis leaves, including induction of two hallmark processes of plant defense: ROS burst and cell wall modifications. Analyses of plants with a mutation in the potentially STm-induced gene EXO70H4 revealed that its encoded protein is required for stomatal defense against STm and E. coli O157:H7, but not against Pst DC3118. In the apoplast however, EXO70H4 is required for defense against STm and Pst DC3118, but not against E. coli O157:H7. Moreover, EXO70H4 is required for callose deposition, but had no function in ROS burst, triggered by all three bacteria. The salicylic acid (SA) signaling and biosynthesis proteins NPR1 and ICS1, respectively, were involved in stomatal and apoplastic defense, as well as callose deposition, against human and plant pathogens. CONCLUSIONS The results show that EXO70H4 is involved in stomatal and apoplastic defenses in Arabidopsis and suggest that EXO70H4-mediated defense play a distinct role in guard cells and leaf mesophyll cells in a bacteria-dependent manner. Nonetheless, EXO70H4 contributes to callose deposition in response to both human and plant pathogens. NPR1 and ICS1, two proteins involved in the SA signaling pathway, are important to inhibit leaf internalization and apoplastic persistence of enterobacteria and proliferation of phytopathogens. These findings highlight the existence of unique and shared plant genetic components to fight off diverse bacterial pathogens providing specific targets for the prevention of foodborne diseases.
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Affiliation(s)
- Paula Rodrigues Oblessuc
- Department of Plant Sciences, University of California, One Shields Avenue, Davis, CA, 95616, USA
| | | | - Maeli Melotto
- Department of Plant Sciences, University of California, One Shields Avenue, Davis, CA, 95616, USA.
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21
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Merget B, Forbes KJ, Brennan F, McAteer S, Shepherd T, Strachan NJC, Holden NJ. Influence of Plant Species, Tissue Type, and Temperature on the Capacity of Shiga-Toxigenic Escherichia coli To Colonize, Grow, and Be Internalized by Plants. Appl Environ Microbiol 2019; 85:e00123-19. [PMID: 30902860 PMCID: PMC6532046 DOI: 10.1128/aem.00123-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 03/20/2019] [Indexed: 12/21/2022] Open
Abstract
Contamination of fresh produce with pathogenic Escherichia coli, including Shiga-toxigenic E. coli (STEC), represents a serious risk to human health. Colonization is governed by multiple bacterial and plant factors that can impact the probability and suitability of bacterial growth. Thus, we aimed to determine whether the growth potential of STEC for plants associated with foodborne outbreaks (two leafy vegetables and two sprouted seed species) is predictive of the colonization of living plants, as assessed from growth kinetics and biofilm formation in plant extracts. The fitness of STEC isolates was compared to that of environmental E. coli isolates at temperatures relevant to plant growth. Growth kinetics in plant extracts varied in a plant-dependent and isolate-dependent manner for all isolates, with spinach leaf lysates supporting the highest rates of growth. Spinach extracts also supported the highest levels of biofilm formation. Saccharides were identified to be the major driver of bacterial growth, although no single metabolite could be correlated with growth kinetics. The highest level of in planta colonization occurred on alfalfa sprouts, though internalization was 10 times more prevalent in the leafy vegetables than in sprouted seeds. Marked differences in in planta growth meant that the growth potential of STEC could be inferred only for sprouted seeds. In contrast, biofilm formation in extracts related to spinach colonization. Overall, the capacity of E. coli to colonize, grow, and be internalized within plants or plant-derived matrices was influenced by the isolate type, plant species, plant tissue type, and temperature, complicating any straightforward relationship between in vitro and in planta behaviors.IMPORTANCE Fresh produce is an important vehicle for STEC transmission, and experimental evidence shows that STEC can colonize plants as secondary hosts, but differences in the capacity to colonize occur between different plant species and tissues. Therefore, an understanding of the impact that these plant factors have on the ability of STEC to grow and establish is required for food safety considerations and risk assessment. Here, we determined whether growth and the ability of STEC to form biofilms in plant extracts could be related to specific plant metabolites or could predict the ability of the bacteria to colonize living plants. Growth rates for sprouted seeds (alfalfa and fenugreek) but not those for leafy vegetables (lettuce and spinach) exhibited a positive relationship between plant extracts and living plants. Therefore, the detailed variations at the level of the bacterial isolate, plant species, and tissue type all need to be considered in risk assessment.
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Affiliation(s)
- Bernhard Merget
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
- School of Biological Sciences, The University of Aberdeen, Aberdeen, United Kingdom
| | - Ken J Forbes
- School of Medicine and Dentistry, The University of Aberdeen, Aberdeen, United Kingdom
| | - Fiona Brennan
- Teagasc, Department of Environment, Soils and Land-Use, Wexford, Republic of Ireland
| | - Sean McAteer
- Roslin Institute & R(D)SVS, The University of Edinburgh, Edinburgh, United Kingdom
| | - Tom Shepherd
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
| | - Norval J C Strachan
- School of Biological Sciences, The University of Aberdeen, Aberdeen, United Kingdom
| | - Nicola J Holden
- Cell and Molecular Sciences, The James Hutton Institute, Dundee, United Kingdom
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Parkunan T, Ashutosh M, Sukumar B, Chera JS, Ramadas S, Chandrasekhar B, Kumar SA, Sharma R, Kumar MS, De S. Antibiotic resistance: A cross-sectional study on knowledge, attitude, and practices among veterinarians of Haryana state in India. Vet World 2019; 12:258-265. [PMID: 31040568 PMCID: PMC6460864 DOI: 10.14202/vetworld.2019.258-265] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 12/22/2018] [Indexed: 01/21/2023] Open
Abstract
Aim: The current study aimed to assess the knowledge, attitude, and practices pertaining to antibiotic usage among the field veterinarians who serve as nodal officers playing a crucial role in disseminating knowledge to the farmers regarding livestock management practices in India. Materials and Methods: A pilot study was conducted in which 106 of the 173 field veterinarians of Haryana, India, agreed to contribute through their valuable participation in the study. The collected data were critically analyzed by simple descriptive statistics, and the responses were ranked using Garrett’s ranking method. Results: Our study found that most of the clinicians were aware of the fundamental clinical aspects of antibiotic resistance (AR), i.e., the general causes and transmission of resistance, response during treatment failure, and safe disposal of hospital waste. Further, implementation of “antibiotic stewardship” (rational/responsible use of antibiotics) and interruption of AR transmission by means of cross-kingdom pathogens are two ways to restrict the spread of resistant pathogens which were not in the clinical purview of majority of the clinicians. This highlights a lack of awareness and scope of improving clinician’s knowledge pertaining to AR. Moreover, we got to know the methodology adopted by farmers for disposal of infected milk from diseased udders as well as their attitude toward diseased and unproductive animals. Conclusion: This study provides snippets of the current animal husbandry practices prevalent at the field level which would assist to plug in the gaps of knowledge regarding AR among the veterinarians as well as the general public and serve to reduce its deleterious impacts in Indian animal farming as well as in the world through the concept of “One World, One Health.”
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Affiliation(s)
- Thulasiraman Parkunan
- Animal Physiology Division, ICAR-National Dairy Research Institute, Karnal, Haryana, India
| | - Manju Ashutosh
- Animal Physiology Division, ICAR-National Dairy Research Institute, Karnal, Haryana, India
| | - Bharathy Sukumar
- National Institute of Epidemiology, Indian Council of Medical Research, Chennai, Tamil Nadu, India
| | - Jatinder Singh Chera
- Animal Genomics Lab, Animal Biotechnology Centre, ICAR-National Dairy Research Institute, Karnal, Haryana, India
| | - Sendhil Ramadas
- Department of Agricultural Statistics, ICAR-Indian Institute of Wheat and Barley Research, Karnal, Haryana, India
| | - B Chandrasekhar
- Dairy Microbiology Division, ICAR-National Dairy Research Institute, Karnal, Haryana, India
| | - S Ashok Kumar
- Dairy Extension Division, ICAR-National Dairy Research Institute, Karnal, Haryana, India
| | - Rachana Sharma
- Animal Physiology Division, ICAR-National Dairy Research Institute, Karnal, Haryana, India
| | - M Santhosh Kumar
- Dairy Microbiology Division, ICAR-National Dairy Research Institute, Karnal, Haryana, India
| | - Sachinandan De
- Animal Genomics Lab, Animal Biotechnology Centre, ICAR-National Dairy Research Institute, Karnal, Haryana, India
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Bulgari D, Montagna M, Gobbi E, Faoro F. Green Technology: Bacteria-Based Approach Could Lead to Unsuspected Microbe⁻Plant⁻Animal Interactions. Microorganisms 2019; 7:microorganisms7020044. [PMID: 30736387 PMCID: PMC6406919 DOI: 10.3390/microorganisms7020044] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/23/2019] [Accepted: 02/02/2019] [Indexed: 12/16/2022] Open
Abstract
The recent and massive revival of green strategies to control plant diseases, mainly as a consequence of the Integrated Pest Management (IPM) rules issued in 2009 by the European Community and the increased consumer awareness of organic products, poses new challenges for human health and food security that need to be addressed in the near future. One of the most important green technologies is biocontrol. This approach is based on living organisms and how these biocontrol agents (BCAs) directly or indirectly interact as a community to control plant pathogens and pest. Although most BCAs have been isolated from plant microbiomes, they share some genomic features, virulence factors, and trans-kingdom infection abilities with human pathogenic microorganisms, thus, their potential impact on human health should be addressed. This evidence, in combination with the outbreaks of human infections associated with consumption of raw fruits and vegetables, opens new questions regarding the role of plants in the human pathogen infection cycle. Moreover, whether BCAs could alter the endophytic bacterial community, thereby leading to the development of new potential human pathogens, is still unclear. In this review, all these issues are debated, highlighting that the research on BCAs and their formulation should include these possible long-lasting consequences of their massive spread in the environment.
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Affiliation(s)
- Daniela Bulgari
- Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, Italy, via Celoria 2, 20133 Milan, Italy.
- Piattaforma di Microbiologia Agroalimentare ed Ambientale (Pi.Mi.A.A.), AgroFood Lab, Department ofMolecular and Translational Medicine, University of Brescia; 25121 Brescia, Italy.
| | - Matteo Montagna
- Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, Italy, via Celoria 2, 20133 Milan, Italy.
| | - Emanuela Gobbi
- Piattaforma di Microbiologia Agroalimentare ed Ambientale (Pi.Mi.A.A.), AgroFood Lab, Department ofMolecular and Translational Medicine, University of Brescia; 25121 Brescia, Italy.
| | - Franco Faoro
- Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy, University of Milan, Italy, via Celoria 2, 20133 Milan, Italy.
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Cowles KN, Groves RL, Barak JD. Leafhopper-Induced Activation of the Jasmonic Acid Response Benefits Salmonella enterica in a Flagellum-Dependent Manner. Front Microbiol 2018; 9:1987. [PMID: 30190716 PMCID: PMC6115507 DOI: 10.3389/fmicb.2018.01987] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 08/07/2018] [Indexed: 11/29/2022] Open
Abstract
Enteric human pathogens such as Salmonella enterica are typically studied in the context of their animal hosts, but it has become apparent that these bacteria spend a significant portion of their life cycle on plants. S. enterica survives the numerous stresses common to a plant niche, including defense responses, water and nutrient limitation, and exposure to UV irradiation leading to an increased potential for human disease. In fact, S. enterica is estimated to cause over one million cases of foodborne illness each year in the United States with 20% of those cases resulting from consumption of contaminated produce. Although S. enterica successfully persists in the plant environment, phytobacterial infection by Pectobacterium carotovorum or Xanthomonas spp. increases S. enterica survival and infrequently leads to growth on infected plants. The co-association of phytophagous insects, such as the Aster leafhopper, Macrosteles quadrilineatus, results in S. enterica populations that persist at higher levels for longer periods of time when compared to plants treated with S. enterica alone. We hypothesized that leafhoppers increase S. enterica persistence by altering the plant defense response to the benefit of the bacteria. Leafhopper infestation activated the jasmonic acid (JA) defense response while S. enterica colonization triggered the salicylic acid (SA) response. In tomato plants co-treated with S. enterica and leafhoppers, both JA- and SA-inducible genes were activated, suggesting that the presence of leafhoppers may affect the crosstalk that occurs between the two immune response pathways. To rule out the possibility that leafhoppers provide additional benefits to S. enterica, plants were treated with a chemical JA analog to activate the immune response in the absence of leafhoppers. Although bacterial populations continue to decline over time, analog treatment significantly increased bacterial persistence on the leaf surface. Bacterial mutant analysis determined that the bacterial flagellum, whether functional or not, was required for increased S. enterica survival after analog treatment. By investigating the interaction between this human pathogen, a common phytophagous insect, and their plant host, we hope to elucidate the mechanisms promoting S. enterica survival on plants and provide information to be used in the development of new food safety intervention strategies.
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Affiliation(s)
- Kimberly N Cowles
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Russell L Groves
- Department of Entomology, University of Wisconsin-Madison, Madison, WI, United States
| | - Jeri D Barak
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
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Jang H, Matthews KR. Influence of surface polysaccharides of Escherichia coli O157:H7 on plant defense response and survival of the human enteric pathogen on Arabidopsis thaliana and lettuce (Lactuca sativa). Food Microbiol 2018; 70:254-261. [PMID: 29173634 DOI: 10.1016/j.fm.2017.10.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/25/2017] [Accepted: 10/19/2017] [Indexed: 12/29/2022]
Abstract
This study aimed to determine the influence of bacterial surface polysaccharides (cellulose, colanic acid, and lipopolysaccharide; LPS) on the colonization or survival of Escherichia coli O157:H7 on plants and the plant defense response. Survival of E. coli O157:H7 were evaluated on Arabidopsis thaliana and romaine lettuce as a model plant and an edible crop (leafy vegetable), respectively. The population of the wild-type strain of E. coli O157:H7 on Arabidopsis plants and lettuce was significantly (P < 0.05) greater compared with the colanic acid-deficient and LPS-truncated mutants on day 1 and day 5 post-inoculation. This result indicates that colanic acid and LPS structures may contribute to the ability of bacterial survival or persistence on plants. The wild-type strain of E. coli O157:H7 produced approximately twice the amount (P < 0.05) of capsular polysaccharide (CPS) than the colanic acid and LPS-truncated mutants. The significantly lower production of CPS was associated with significantly greater (2-fold) expression of pathogenesis-related gene (PR1) compared with the wild-type and cellulose-deficient mutant (P < 0.05). Collectively, the results of this study may suggest that specific surface polysaccharides of E. coli O157:H7 differentially induce the plant defense response, consequently affecting the survival of the human pathogen on plants. The survival and persistence of E. coli O157:H7 was similar on Arabidopsis and lettuce regardless of day post-inoculation.
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Affiliation(s)
- Hyein Jang
- Department of Food Science, Rutgers University, New Brunswick, NJ 08901, USA
| | - Karl R Matthews
- Department of Food Science, Rutgers University, New Brunswick, NJ 08901, USA.
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Brito PH, Chevreux B, Serra CR, Schyns G, Henriques AO, Pereira-Leal JB. Genetic Competence Drives Genome Diversity in Bacillus subtilis. Genome Biol Evol 2018; 10:108-124. [PMID: 29272410 PMCID: PMC5765554 DOI: 10.1093/gbe/evx270] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2017] [Indexed: 12/18/2022] Open
Abstract
Prokaryote genomes are the result of a dynamic flux of genes, with increases achieved via horizontal gene transfer and reductions occurring through gene loss. The ecological and selective forces that drive this genomic flexibility vary across species. Bacillus subtilis is a naturally competent bacterium that occupies various environments, including plant-associated, soil, and marine niches, and the gut of both invertebrates and vertebrates. Here, we quantify the genomic diversity of B. subtilis and infer the genome dynamics that explain the high genetic and phenotypic diversity observed. Phylogenomic and comparative genomic analyses of 42 B. subtilis genomes uncover a remarkable genome diversity that translates into a core genome of 1,659 genes and an asymptotic pangenome growth rate of 57 new genes per new genome added. This diversity is due to a large proportion of low-frequency genes that are acquired from closely related species. We find no gene-loss bias among wild isolates, which explains why the cloud genome, 43% of the species pangenome, represents only a small proportion of each genome. We show that B. subtilis can acquire xenologous copies of core genes that propagate laterally among strains within a niche. While not excluding the contributions of other mechanisms, our results strongly suggest a process of gene acquisition that is largely driven by competence, where the long-term maintenance of acquired genes depends on local and global fitness effects. This competence-driven genomic diversity provides B. subtilis with its generalist character, enabling it to occupy a wide range of ecological niches and cycle through them.
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Affiliation(s)
- Patrícia H Brito
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Nova Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Portugal
| | - Bastien Chevreux
- DSM Nutritional Products, Ltd., 60 Westview street, Lexington MA, USA
| | - Cláudia R Serra
- Instituto de Tecnologia Química e Biológica, Oeiras, Portugal
| | - Ghislain Schyns
- DSM Nutritional Products, Ltd., 60 Westview street, Lexington MA, USA
| | | | - José B Pereira-Leal
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Ophiomics—Precision Medicine, Lisbon, Portugal
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28
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Food recalls and warnings due to the presence of foodborne pathogens — a focus on fresh fruits, vegetables, dairy and eggs. Curr Opin Food Sci 2017. [DOI: 10.1016/j.cofs.2017.11.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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29
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Melotto M, Zhang L, Oblessuc PR, He SY. Stomatal Defense a Decade Later. PLANT PHYSIOLOGY 2017; 174:561-571. [PMID: 28341769 PMCID: PMC5462020 DOI: 10.1104/pp.16.01853] [Citation(s) in RCA: 171] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/22/2017] [Indexed: 05/18/2023]
Abstract
A decade has passed since the discovery of stomatal defense, and the field has expanded considerably with significant understanding of the basic mechanisms underlying the process.
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Affiliation(s)
- Maeli Melotto
- Department of Plant Sciences, University of California, Davis, California 95616 (M.M., P.R.O.);
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824 (L.Z., S.Y.H.);
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824 (L.Z., S.Y.H.); and
- Plant Resilience Institute, Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Michigan State University, East Lansing, Michigan 48824 (S.Y.H.)
| | - Li Zhang
- Department of Plant Sciences, University of California, Davis, California 95616 (M.M., P.R.O.)
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824 (L.Z., S.Y.H.)
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824 (L.Z., S.Y.H.); and
- Plant Resilience Institute, Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Michigan State University, East Lansing, Michigan 48824 (S.Y.H.)
| | - Paula R Oblessuc
- Department of Plant Sciences, University of California, Davis, California 95616 (M.M., P.R.O.)
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824 (L.Z., S.Y.H.)
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824 (L.Z., S.Y.H.); and
- Plant Resilience Institute, Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Michigan State University, East Lansing, Michigan 48824 (S.Y.H.)
| | - Sheng Yang He
- Department of Plant Sciences, University of California, Davis, California 95616 (M.M., P.R.O.);
- Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824 (L.Z., S.Y.H.);
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824 (L.Z., S.Y.H.); and
- Plant Resilience Institute, Howard Hughes Medical Institute-Gordon and Betty Moore Foundation, Michigan State University, East Lansing, Michigan 48824 (S.Y.H.)
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Wright KM, Crozier L, Marshall J, Merget B, Holmes A, Holden NJ. Differences in internalization and growth of Escherichia coli O157:H7 within the apoplast of edible plants, spinach and lettuce, compared with the model species Nicotiana benthamiana. Microb Biotechnol 2017; 10:555-569. [PMID: 28169510 PMCID: PMC5404196 DOI: 10.1111/1751-7915.12596] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 12/14/2016] [Indexed: 11/30/2022] Open
Abstract
Internalization of food-borne bacteria into edible parts of fresh produce plants represents a serious health risk. Therefore, internalization of verocytotoxigenic E. coli O157:H7 isolate Sakai was assessed in two species associated with outbreaks, spinach (Spinacia oleracea) and lettuce (Lactuca sativa) and compared to the model species Nicotiana benthamiana. Internalization occurred in the leaves and roots of spinach and lettuce throughout a 10 day time-course. The plant species, tissue type and inoculum dose all impacted the outcome. A combination of low inoculum dose (~102 CFU) together with light microscopy imaging highlighted marked differences in the fate of endophytic E. coli O157:H7 Sakai. In the fresh produce species, bacterial growth was restricted but viable cells persisted over 20 days, whereas there was > 400-fold (~2.5 Log10 ) increase in growth in N. benthamiana. Colony formation occurred adjacent to epidermal cells and mesophyll cells or close to vascular bundles of N. benthamiana and contained components of a biofilm matrix, including curli expression and elicitation, extracellular DNA and a limited presence of cellulose. Together the data show that internalization is a relevant issue in crop production and that crop species and tissue need to be considered as food safety risk parameters.
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Affiliation(s)
| | - Louise Crozier
- Cell and Molecular SciencesThe James Hutton InstituteDundeeUK
| | | | - Bernhard Merget
- Cell and Molecular SciencesThe James Hutton InstituteDundeeUK
| | - Ashleigh Holmes
- Cell and Molecular SciencesThe James Hutton InstituteDundeeUK
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31
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Gayatri G, Agurla S, Kuchitsu K, Anil K, Podile AR, Raghavendra AS. Stomatal Closure and Rise in ROS/NO of Arabidopsis Guard Cells by Tobacco Microbial Elicitors: Cryptogein and Harpin. FRONTIERS IN PLANT SCIENCE 2017; 8:1096. [PMID: 28680439 PMCID: PMC5478720 DOI: 10.3389/fpls.2017.01096] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 06/06/2017] [Indexed: 05/11/2023]
Abstract
Plants use stomatal closure mediated by elicitors as the first step of the innate immune response to restrict the microbial entry. We present a comprehensive study of the effect of cryptogein and harpin, two elicitors from microbial pathogens of tobacco, on stomatal closure and guard cell signaling components in Arabidopsis thaliana, a model plant. Cryptogein as well as harpin induced stomatal closure, while elevating the levels of reactive oxygen species (ROS) and nitric oxide (NO) in the guard cells of A. thaliana. Kinetic studies with fluorescent dyes revealed that the rise in ROS levels preceded that of NO in guard cells, when treated with these two elicitors. The restriction of NO levels in guard cells, even by ROS modulators indicates the essentiality of ROS for NO production during elicitor-triggered stomatal closure. The signaling events during elicitor-induced stomatal closure appear to converge at NADPH oxidase and ROS production. Our results provide the first report on stomatal closure associated with rise in ROS/NO of guard cells by cryptogein and harpin in A. thaliana. Our results establish that A. thaliana can be used to study stomatal responses to the typical elicitors from microbial pathogens of other plants. The suitability of Arabidopsis opens up an excellent scope for further studies on signaling events leading to stomatal closure by microbial elicitors.
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Affiliation(s)
- Gunja Gayatri
- Department of Plant Sciences, School of Life Sciences, University of HyderabadHyderabad, India
| | - Srinivas Agurla
- Department of Plant Sciences, School of Life Sciences, University of HyderabadHyderabad, India
| | - Kazuyuki Kuchitsu
- Department of Applied Biological Science, Tokyo University of ScienceChiba, Japan
| | - Kondreddy Anil
- Department of Plant Sciences, School of Life Sciences, University of HyderabadHyderabad, India
| | - Appa R. Podile
- Department of Plant Sciences, School of Life Sciences, University of HyderabadHyderabad, India
| | - Agepati S. Raghavendra
- Department of Plant Sciences, School of Life Sciences, University of HyderabadHyderabad, India
- *Correspondence: Agepati S. Raghavendra, ;
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32
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Noshi M, Mori D, Tanabe N, Maruta T, Shigeoka S. Arabidopsis clade IV TGA transcription factors, TGA10 and TGA9, are involved in ROS-mediated responses to bacterial PAMP flg22. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 252:12-21. [PMID: 27717447 DOI: 10.1016/j.plantsci.2016.06.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 06/15/2016] [Accepted: 06/27/2016] [Indexed: 05/22/2023]
Abstract
Reactive oxygen species (ROS) produced in chloroplasts have been proposed to act as signaling molecules for plant immunity through pathogen-associated molecular patterns (PAMPs), such as flg22. To elucidate this process, we herein conducted genetic screening of flg22-sensitive mutants from T-DNA insertion lines lacking chloroplastic H2O2-responsive genes. The results obtained showed that knockout mutants lacking a clade IV TGA transcription factor, TGA10, were more sensitive to the flg22 treatment than wild-type plants. Furthermore, although no flg22-sensitive phenotype was detected in the knockout mutant of another clade IV TGA9, double knockout tga9 tga10 mutants showed more sensitivity to flg22 than single knockout mutants. Transcripts of TGA10 and TGA9 were strongly induced by flg22 in leaves, and this was facilitated by the double knockout of stromal and thylakoid-bound ascorbate peroxidases (APX), which are major H2O2 scavengers in chloroplasts. The flg22-induced H2O2 accumulation was maintained at high level in these APXs mutants, indicating the clade IV TGAs may be induced by the ROS. Furthermore, TGA10 was required for the complete activation of the expression of several flg22-responsive genes in plants treated with this PAMP. These have provided a new insight into the relationship between the TGA transcription factors and ROS-mediated signaling in PAMPs responses.
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Affiliation(s)
- Masahiro Noshi
- Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, Nakamachi, Nara 631-8505, Japan.
| | - Daisuke Mori
- Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, Nakamachi, Nara 631-8505, Japan.
| | - Noriaki Tanabe
- Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, Nakamachi, Nara 631-8505, Japan.
| | - Takanori Maruta
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University, 1060 Nishikawatsu, Matsue, Shimane 690-8504, Japan.
| | - Shigeru Shigeoka
- Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, Nakamachi, Nara 631-8505, Japan.
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33
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Debode J, De Tender C, Soltaninejad S, Van Malderghem C, Haegeman A, Van der Linden I, Cottyn B, Heyndrickx M, Maes M. Chitin Mixed in Potting Soil Alters Lettuce Growth, the Survival of Zoonotic Bacteria on the Leaves and Associated Rhizosphere Microbiology. Front Microbiol 2016; 7:565. [PMID: 27148242 PMCID: PMC4838818 DOI: 10.3389/fmicb.2016.00565] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Accepted: 04/04/2016] [Indexed: 11/13/2022] Open
Abstract
Chitin is a promising soil amendment for improving soil quality, plant growth, and plant resilience. The objectives of this study were twofold. First, to study the effect of chitin mixed in potting soil on lettuce growth and on the survival of two zoonotic bacterial pathogens, Escherichia coli O157:H7 and Salmonella enterica on the lettuce leaves. Second, to assess the related changes in the microbial lettuce rhizosphere, using phospholipid fatty acid (PLFA) analysis and amplicon sequencing of a bacterial 16S rRNA gene fragment and the fungal ITS2. As a result of chitin addition, lettuce fresh yield weight was significantly increased. S. enterica survival in the lettuce phyllosphere was significantly reduced. The E. coli O157:H7 survival was also lowered, but not significantly. Moreover, significant changes were observed in the bacterial and fungal community of the lettuce rhizosphere. PLFA analysis showed a significant increase in fungal and bacterial biomass. Amplicon sequencing showed no increase in fungal and bacterial biodiversity, but relative abundances of the bacterial phyla Acidobacteria, Verrucomicrobia, Actinobacteria, Bacteroidetes, and Proteobacteria and the fungal phyla Ascomycota, Basidiomycota, and Zygomycota were significantly changed. More specifically, a more than 10-fold increase was observed for operational taxonomic units belonging to the bacterial genera Cellvibrio, Pedobacter, Dyadobacter, and Streptomyces and to the fungal genera Lecanicillium and Mortierella. These genera include several species previously reported to be involved in biocontrol, plant growth promotion, the nitrogen cycle and chitin degradation. These results enhance the understanding of the response of the rhizosphere microbiome to chitin amendment. Moreover, this is the first study to investigate the use of soil amendments to control the survival of S. enterica on plant leaves.
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Affiliation(s)
- Jane Debode
- Plant Sciences Unit, Institute for Agricultural and Fisheries ResearchMerelbeke, Belgium
| | - Caroline De Tender
- Plant Sciences Unit, Institute for Agricultural and Fisheries ResearchMerelbeke, Belgium
| | - Saman Soltaninejad
- Plant Sciences Unit, Institute for Agricultural and Fisheries ResearchMerelbeke, Belgium
- Technology and Food Science Unit, Institute for Agricultural and Fisheries ResearchMelle, Belgium
| | - Cinzia Van Malderghem
- Plant Sciences Unit, Institute for Agricultural and Fisheries ResearchMerelbeke, Belgium
| | - Annelies Haegeman
- Plant Sciences Unit, Institute for Agricultural and Fisheries ResearchMerelbeke, Belgium
| | - Inge Van der Linden
- Technology and Food Science Unit, Institute for Agricultural and Fisheries ResearchMelle, Belgium
- Department of Food Safety and Food Quality, Ghent UniversityGhent, Belgium
| | - Bart Cottyn
- Plant Sciences Unit, Institute for Agricultural and Fisheries ResearchMerelbeke, Belgium
| | - Marc Heyndrickx
- Technology and Food Science Unit, Institute for Agricultural and Fisheries ResearchMelle, Belgium
- Department of Pathology, Bacteriology, and Poultry Diseases, Faculty of Veterinary Sciences, Ghent UniversityMerelbeke, Belgium
| | - Martine Maes
- Plant Sciences Unit, Institute for Agricultural and Fisheries ResearchMerelbeke, Belgium
- Department of Biochemistry and Microbiology, Ghent UniversityGhent, Belgium
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34
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Holden NJ, Jackson RW, Schikora A. Editorial on plants as alternative hosts for human and animal pathogens. Front Microbiol 2015; 6:397. [PMID: 25983729 PMCID: PMC4415427 DOI: 10.3389/fmicb.2015.00397] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 04/17/2015] [Indexed: 11/16/2022] Open
Affiliation(s)
- Nicola J Holden
- Human and Animal Pathogen - Plant Interactions, The James Hutton Institute Dundee, UK
| | - Robert W Jackson
- School of Biological Sciences, University of Reading Reading, UK
| | - Adam Schikora
- Institute of Phytopathology and Applied Zoology, Justus Liebig University of Giessen Giessen, Germany
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35
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Arnaud D, Hwang I. A sophisticated network of signaling pathways regulates stomatal defenses to bacterial pathogens. MOLECULAR PLANT 2015; 8:566-81. [PMID: 25661059 DOI: 10.1016/j.molp.2014.10.012] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Revised: 10/25/2014] [Accepted: 10/26/2014] [Indexed: 05/03/2023]
Abstract
Guard cells are specialized cells forming stomatal pores at the leaf surface for gas exchanges between the plant and the atmosphere. Stomata have been shown to play an important role in plant defense as a part of the innate immune response. Plants actively close their stomata upon contact with microbes, thereby preventing pathogen entry into the leaves and the subsequent colonization of host tissues. In this review, we present current knowledge of molecular mechanisms and signaling pathways implicated in stomatal defenses, with particular emphasis on plant-bacteria interactions. Stomatal defense responses begin from the perception of pathogen-associated molecular patterns (PAMPs) and activate a signaling cascade involving the production of secondary messengers such as reactive oxygen species, nitric oxide, and calcium for the regulation of plasma membrane ion channels. The analyses on downstream molecular mechanisms implicated in PAMP-triggered stomatal closure have revealed extensive interplays among the components regulating hormonal signaling pathways. We also discuss the strategies deployed by pathogenic bacteria to counteract stomatal immunity through the example of the phytotoxin coronatine.
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Affiliation(s)
- Dominique Arnaud
- Department of Life Sciences, POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 790-784, Korea.
| | - Ildoo Hwang
- Department of Life Sciences, POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 790-784, Korea
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36
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Wiedemann A, Virlogeux-Payant I, Chaussé AM, Schikora A, Velge P. Interactions of Salmonella with animals and plants. Front Microbiol 2015; 5:791. [PMID: 25653644 PMCID: PMC4301013 DOI: 10.3389/fmicb.2014.00791] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 12/22/2014] [Indexed: 12/16/2022] Open
Abstract
Salmonella enterica species are Gram-negative bacteria, which are responsible for a wide range of food- and water-borne diseases in both humans and animals, thereby posing a major threat to public health. Recently, there has been an increasing number of reports, linking Salmonella contaminated raw vegetables and fruits with food poisoning. Many studies have shown that an essential feature of the pathogenicity of Salmonella is its capacity to cross a number of barriers requiring invasion of a large variety of cells and that the extent of internalization may be influenced by numerous factors. However, it is poorly understood how Salmonella successfully infects hosts as diversified as animals or plants. The aim of this review is to describe the different stages required for Salmonella interaction with its hosts: (i) attachment to host surfaces; (ii) entry processes; (iii) multiplication; (iv) suppression of host defense mechanisms; and to point out similarities and differences between animal and plant infections.
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Affiliation(s)
- Agnès Wiedemann
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique Nouzilly, France ; UMR1282 Infectiologie et Santé Publique, Université François Rabelais Tours, France
| | - Isabelle Virlogeux-Payant
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique Nouzilly, France ; UMR1282 Infectiologie et Santé Publique, Université François Rabelais Tours, France
| | - Anne-Marie Chaussé
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique Nouzilly, France ; UMR1282 Infectiologie et Santé Publique, Université François Rabelais Tours, France
| | - Adam Schikora
- Institute for Phytopathology, Research Center for BioSystems, Land Use and Nutrition (IFZ), Justus Liebig University Giessen Giessen, Germany
| | - Philippe Velge
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique Nouzilly, France ; UMR1282 Infectiologie et Santé Publique, Université François Rabelais Tours, France
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