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The use of flagella and motility for plant colonization and fitness by different strains of the foodborne pathogen Listeria monocytogenes.

Gorski L, Duhé JM, Flaherty D - PLoS ONE (2009)

Bottom Line: The motAB mutants were not affected in the colonization of alfalfa, radish, and broccoli sprouts; however, some of the flaA mutants showed reduced colonization ability.The best colonizing wild type strain was reduced in colonization on all three sprout types as a result of a flaA deletion.Here the flaA and motAB mutants of the three strain backgrounds were impaired in fitness of colonization of alfalfa and radish sprouts, and one strain background showed reduced fitness of both mutant types on broccoli sprouts.

View Article: PubMed Central - PubMed

Affiliation: US Department of Agriculture, Produce Safety and Microbiology Research Unit, Agricultural Research Service, Albany, California, United States of America. lisa.gorski@ars.usda.gov

ABSTRACT
The role of flagella and motility in the attachment of the foodborne pathogen Listeria monocytogenes to various surfaces is mixed with some systems requiring flagella for an interaction and others needing only motility for cells to get to the surface. In nature this bacterium is a saprophyte and contaminated produce is an avenue for infection. Previous studies have documented the ability of this organism to attach to and colonize plant tissue. Motility mutants were generated in three wild type strains of L. monocytogenes by deleting either flaA, the gene encoding flagellin, or motAB, genes encoding part of the flagellar motor, and tested for both the ability to colonize sprouts and for the fitness of that colonization. The motAB mutants were not affected in the colonization of alfalfa, radish, and broccoli sprouts; however, some of the flaA mutants showed reduced colonization ability. The best colonizing wild type strain was reduced in colonization on all three sprout types as a result of a flaA deletion. A mutant in another background was only affected on alfalfa. The third, a poor alfalfa colonizer was not affected in colonization ability by any of the deletions. Fitness of colonization was measured in experiments of competition between mixtures of mutant and parent strains on sprouts. Here the flaA and motAB mutants of the three strain backgrounds were impaired in fitness of colonization of alfalfa and radish sprouts, and one strain background showed reduced fitness of both mutant types on broccoli sprouts. Together these data indicate a role for flagella for some strains to physically colonize some plants, while the fitness of that colonization is positively affected by motility in almost all cases.

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Colony spread of strains in soft agar.Strains were toothpicked onto BHI+0.4% agar, and grown at 30°C. Row 1 contains strains in the 10403 background, Row 2 contains strains in the RM2387 background, and Row 3 contains strains in the RM2992 background.
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pone-0005142-g001: Colony spread of strains in soft agar.Strains were toothpicked onto BHI+0.4% agar, and grown at 30°C. Row 1 contains strains in the 10403 background, Row 2 contains strains in the RM2387 background, and Row 3 contains strains in the RM2992 background.

Mentions: To determine if these mutants behaved as motility mutants, they were tested in soft agar to determine the amount of colony spread (Figure 1), and they were observed microscopically both in wet mounts and after flagellar staining (Figure 2). In motility agar all of the ΔflaA and ΔmotAB mutants displayed small colony spreading phenotypes, indicating a lack of motility. Furthermore, all of the mutants were non-motile in wet mounts observed under the phase contrast microscope. Observations after flagellar staining showed that none of the ΔflaA mutants had visible flagella on their cell surfaces; whereas all of the wild types and the ΔmotAB mutant strains did. These data indicate that the ΔflaA mutants were non-motile due to a lack of flagella, and the ΔmotAB mutants were non-motile due to non-functional, but present flagella. Complementation of all the ΔflaA and ΔmotAB mutants with a plasmid carrying the wild type gene in trans resulted in motile phenotypes (data not shown).


The use of flagella and motility for plant colonization and fitness by different strains of the foodborne pathogen Listeria monocytogenes.

Gorski L, Duhé JM, Flaherty D - PLoS ONE (2009)

Colony spread of strains in soft agar.Strains were toothpicked onto BHI+0.4% agar, and grown at 30°C. Row 1 contains strains in the 10403 background, Row 2 contains strains in the RM2387 background, and Row 3 contains strains in the RM2992 background.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2664462&req=5

pone-0005142-g001: Colony spread of strains in soft agar.Strains were toothpicked onto BHI+0.4% agar, and grown at 30°C. Row 1 contains strains in the 10403 background, Row 2 contains strains in the RM2387 background, and Row 3 contains strains in the RM2992 background.
Mentions: To determine if these mutants behaved as motility mutants, they were tested in soft agar to determine the amount of colony spread (Figure 1), and they were observed microscopically both in wet mounts and after flagellar staining (Figure 2). In motility agar all of the ΔflaA and ΔmotAB mutants displayed small colony spreading phenotypes, indicating a lack of motility. Furthermore, all of the mutants were non-motile in wet mounts observed under the phase contrast microscope. Observations after flagellar staining showed that none of the ΔflaA mutants had visible flagella on their cell surfaces; whereas all of the wild types and the ΔmotAB mutant strains did. These data indicate that the ΔflaA mutants were non-motile due to a lack of flagella, and the ΔmotAB mutants were non-motile due to non-functional, but present flagella. Complementation of all the ΔflaA and ΔmotAB mutants with a plasmid carrying the wild type gene in trans resulted in motile phenotypes (data not shown).

Bottom Line: The motAB mutants were not affected in the colonization of alfalfa, radish, and broccoli sprouts; however, some of the flaA mutants showed reduced colonization ability.The best colonizing wild type strain was reduced in colonization on all three sprout types as a result of a flaA deletion.Here the flaA and motAB mutants of the three strain backgrounds were impaired in fitness of colonization of alfalfa and radish sprouts, and one strain background showed reduced fitness of both mutant types on broccoli sprouts.

View Article: PubMed Central - PubMed

Affiliation: US Department of Agriculture, Produce Safety and Microbiology Research Unit, Agricultural Research Service, Albany, California, United States of America. lisa.gorski@ars.usda.gov

ABSTRACT
The role of flagella and motility in the attachment of the foodborne pathogen Listeria monocytogenes to various surfaces is mixed with some systems requiring flagella for an interaction and others needing only motility for cells to get to the surface. In nature this bacterium is a saprophyte and contaminated produce is an avenue for infection. Previous studies have documented the ability of this organism to attach to and colonize plant tissue. Motility mutants were generated in three wild type strains of L. monocytogenes by deleting either flaA, the gene encoding flagellin, or motAB, genes encoding part of the flagellar motor, and tested for both the ability to colonize sprouts and for the fitness of that colonization. The motAB mutants were not affected in the colonization of alfalfa, radish, and broccoli sprouts; however, some of the flaA mutants showed reduced colonization ability. The best colonizing wild type strain was reduced in colonization on all three sprout types as a result of a flaA deletion. A mutant in another background was only affected on alfalfa. The third, a poor alfalfa colonizer was not affected in colonization ability by any of the deletions. Fitness of colonization was measured in experiments of competition between mixtures of mutant and parent strains on sprouts. Here the flaA and motAB mutants of the three strain backgrounds were impaired in fitness of colonization of alfalfa and radish sprouts, and one strain background showed reduced fitness of both mutant types on broccoli sprouts. Together these data indicate a role for flagella for some strains to physically colonize some plants, while the fitness of that colonization is positively affected by motility in almost all cases.

Show MeSH
Related in: MedlinePlus