<named-content content-type="genus-species">Salmonella enterica</named-content> Suppresses <named-content content-type="genus-species">Pectobacterium carotovorum</named-content> subsp. <italic toggle="yes">carotovorum</italic> Population and Soft Rot Progression by Acidifying the Microaerophilic Environment
ABSTRACT Although enteric human pathogens are usually studied in the context of their animal hosts, a significant portion of their life cycle occurs on plants. Plant disease alters the phyllosphere, leading to enhanced growth of human pathogens; however, the impact of human pathogens on phytopathoge...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2013-03-01
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| Series: | mBio |
| Online Access: | https://journals.asm.org/doi/10.1128/mBio.00557-12 |
| _version_ | 1818683369936912384 |
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| author | Grace Kwan Amy O. Charkowski Jeri D. Barak |
| author_facet | Grace Kwan Amy O. Charkowski Jeri D. Barak |
| author_sort | Grace Kwan |
| collection | DOAJ |
| description | ABSTRACT Although enteric human pathogens are usually studied in the context of their animal hosts, a significant portion of their life cycle occurs on plants. Plant disease alters the phyllosphere, leading to enhanced growth of human pathogens; however, the impact of human pathogens on phytopathogen biology and plant health is largely unknown. To characterize the interaction between human pathogens and phytobacterial pathogens in the phyllosphere, we examined the interactions between Pectobacterium carotovorum subsp. carotovorum and Salmonella enterica or Escherichia coli O157:H7 with regard to bacterial populations, soft rot progression, and changes in local pH. The presence of P. carotovorum subsp. carotovorum enhanced the growth of both S. enterica and E. coli O157:H7 on leaves. However, in a microaerophilic environment, S. enterica reduced P. carotovorum subsp. carotovorum populations and soft rot progression by moderating local environmental pH. Reduced soft rot was not due to S. enterica proteolytic activity. Limitations on P. carotovorum subsp. carotovorum growth, disease progression, and pH elevation were not observed on leaves coinoculated with E. coli O157:H7 or when leaves were coinoculated with S. enterica in an aerobic environment. S. enterica also severely undermined the relationship between the phytobacterial population and disease progression of a P. carotovorum subsp. carotovorum budB mutant defective in the 2,3-butanediol pathway for acid neutralization. Our results show that S. enterica and E. coli O157:H7 interact differently with the enteric phytobacterial pathogen P. carotovorum subsp. carotovorum. S. enterica inhibition of soft rot progression may conceal a rapidly growing human pathogen population. Whereas soft rotted produce can alert consumers to the possibility of food-borne pathogens, healthy-looking produce may entice consumption of contaminated vegetables. IMPORTANCE Salmonella enterica and Escherichia coli O157:H7 may use plants to move between animal and human hosts. Their populations are higher on plants cocolonized with the common bacterial soft rot pathogen Pectobacterium carotovorum subsp. carotovorum, turning edible plants into a risk factor for human disease. We inoculated leaves with P. carotovorum subsp. carotovorum and S. enterica or E. coli O157:H7 to study the interactions between these bacteria. While P. carotovorum subsp. carotovorum enhanced the growth of both S. enterica and E. coli O157:H7, these human pathogens affected P. carotovorum subsp. carotovorum fundamentally differently. S. enterica reduced P. carotovorum subsp. carotovorum growth and acidified the environment, leading to less soft rot on leaves; E. coli O157:H7 had no such effects. As soft rot signals a food safety risk, the reduction of soft rot symptoms in the presence of S. enterica may lead consumers to eat healthy-looking but S. enterica-contaminated produce. |
| first_indexed | 2024-12-17T10:33:39Z |
| format | Article |
| id | doaj.art-6a2d2d75f6e14cf79b9cd417f5664228 |
| institution | Directory Open Access Journal |
| issn | 2150-7511 |
| language | English |
| last_indexed | 2024-12-17T10:33:39Z |
| publishDate | 2013-03-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mBio |
| spelling | doaj.art-6a2d2d75f6e14cf79b9cd417f56642282022-12-21T21:52:27ZengAmerican Society for MicrobiologymBio2150-75112013-03-014110.1128/mBio.00557-12<named-content content-type="genus-species">Salmonella enterica</named-content> Suppresses <named-content content-type="genus-species">Pectobacterium carotovorum</named-content> subsp. <italic toggle="yes">carotovorum</italic> Population and Soft Rot Progression by Acidifying the Microaerophilic EnvironmentGrace Kwan0Amy O. Charkowski1Jeri D. Barak2Department of Plant Pathology, University of Wisconsin---Madison, Madison, Wisconsin, USADepartment of Plant Pathology, University of Wisconsin---Madison, Madison, Wisconsin, USADepartment of Plant Pathology, University of Wisconsin---Madison, Madison, Wisconsin, USAABSTRACT Although enteric human pathogens are usually studied in the context of their animal hosts, a significant portion of their life cycle occurs on plants. Plant disease alters the phyllosphere, leading to enhanced growth of human pathogens; however, the impact of human pathogens on phytopathogen biology and plant health is largely unknown. To characterize the interaction between human pathogens and phytobacterial pathogens in the phyllosphere, we examined the interactions between Pectobacterium carotovorum subsp. carotovorum and Salmonella enterica or Escherichia coli O157:H7 with regard to bacterial populations, soft rot progression, and changes in local pH. The presence of P. carotovorum subsp. carotovorum enhanced the growth of both S. enterica and E. coli O157:H7 on leaves. However, in a microaerophilic environment, S. enterica reduced P. carotovorum subsp. carotovorum populations and soft rot progression by moderating local environmental pH. Reduced soft rot was not due to S. enterica proteolytic activity. Limitations on P. carotovorum subsp. carotovorum growth, disease progression, and pH elevation were not observed on leaves coinoculated with E. coli O157:H7 or when leaves were coinoculated with S. enterica in an aerobic environment. S. enterica also severely undermined the relationship between the phytobacterial population and disease progression of a P. carotovorum subsp. carotovorum budB mutant defective in the 2,3-butanediol pathway for acid neutralization. Our results show that S. enterica and E. coli O157:H7 interact differently with the enteric phytobacterial pathogen P. carotovorum subsp. carotovorum. S. enterica inhibition of soft rot progression may conceal a rapidly growing human pathogen population. Whereas soft rotted produce can alert consumers to the possibility of food-borne pathogens, healthy-looking produce may entice consumption of contaminated vegetables. IMPORTANCE Salmonella enterica and Escherichia coli O157:H7 may use plants to move between animal and human hosts. Their populations are higher on plants cocolonized with the common bacterial soft rot pathogen Pectobacterium carotovorum subsp. carotovorum, turning edible plants into a risk factor for human disease. We inoculated leaves with P. carotovorum subsp. carotovorum and S. enterica or E. coli O157:H7 to study the interactions between these bacteria. While P. carotovorum subsp. carotovorum enhanced the growth of both S. enterica and E. coli O157:H7, these human pathogens affected P. carotovorum subsp. carotovorum fundamentally differently. S. enterica reduced P. carotovorum subsp. carotovorum growth and acidified the environment, leading to less soft rot on leaves; E. coli O157:H7 had no such effects. As soft rot signals a food safety risk, the reduction of soft rot symptoms in the presence of S. enterica may lead consumers to eat healthy-looking but S. enterica-contaminated produce.https://journals.asm.org/doi/10.1128/mBio.00557-12 |
| spellingShingle | Grace Kwan Amy O. Charkowski Jeri D. Barak <named-content content-type="genus-species">Salmonella enterica</named-content> Suppresses <named-content content-type="genus-species">Pectobacterium carotovorum</named-content> subsp. <italic toggle="yes">carotovorum</italic> Population and Soft Rot Progression by Acidifying the Microaerophilic Environment mBio |
| title | <named-content content-type="genus-species">Salmonella enterica</named-content> Suppresses <named-content content-type="genus-species">Pectobacterium carotovorum</named-content> subsp. <italic toggle="yes">carotovorum</italic> Population and Soft Rot Progression by Acidifying the Microaerophilic Environment |
| title_full | <named-content content-type="genus-species">Salmonella enterica</named-content> Suppresses <named-content content-type="genus-species">Pectobacterium carotovorum</named-content> subsp. <italic toggle="yes">carotovorum</italic> Population and Soft Rot Progression by Acidifying the Microaerophilic Environment |
| title_fullStr | <named-content content-type="genus-species">Salmonella enterica</named-content> Suppresses <named-content content-type="genus-species">Pectobacterium carotovorum</named-content> subsp. <italic toggle="yes">carotovorum</italic> Population and Soft Rot Progression by Acidifying the Microaerophilic Environment |
| title_full_unstemmed | <named-content content-type="genus-species">Salmonella enterica</named-content> Suppresses <named-content content-type="genus-species">Pectobacterium carotovorum</named-content> subsp. <italic toggle="yes">carotovorum</italic> Population and Soft Rot Progression by Acidifying the Microaerophilic Environment |
| title_short | <named-content content-type="genus-species">Salmonella enterica</named-content> Suppresses <named-content content-type="genus-species">Pectobacterium carotovorum</named-content> subsp. <italic toggle="yes">carotovorum</italic> Population and Soft Rot Progression by Acidifying the Microaerophilic Environment |
| title_sort | named content content type genus species salmonella enterica named content suppresses named content content type genus species pectobacterium carotovorum named content subsp italic toggle yes carotovorum italic population and soft rot progression by acidifying the microaerophilic environment |
| url | https://journals.asm.org/doi/10.1128/mBio.00557-12 |
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