Submitted to: PLoS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2009
Publication Date: 4/9/2009
Citation: Gorski, L.A., Duhe, J., Flaherty, D. 2009. The use of Flagella and Motility for plant colonization and fitness by different strains of the foodborne pathogen Listeria monocytogenes. PLoS One. Available:http:/www.plose.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0005142 published on-line : e5142
Interpretive Summary: In nature the foodborne pathogen Listeria monocytogenes lives in soil and on decaying plant tissue. Thus contaminated produce is an avenue for infection. We studied colonization of plant tissue by L. monocytogenes using sprouts as a model, and testing if flagella are used as a means of attachment and colonization. Mutants were generated in three L. monocytogenes strains in genes that regulate both the production of flagella and the function of flagella, and they were tested to see if they were affected in sprout colonization. Mutants without flagella were reduced in colonization, but mutants with paralyzed flagella were not. Therefore, some strains of L. monocytogenes use flagella as a means to attach to and colonize alfalfa, radish, and broccoli sprouts. The fitness of colonization of sprouts by the mutants was tested by putting them in competition with wild type strains in mixed cultures. Flagella may play a direct role in the colonization of some sprout tissue by some strains of L. monocytogenes. However fitness of colonization was affected by motility for all strains on alfalfa and radish sprouts and for one strain on broccoli sprouts.
Technical 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 the ability to colonize sprouts and for fitness in 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, indicating a role for flagella for some strains to colonize some plants. 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 originally was not affected in colonization by any of the deletions. Fitness in colonization was measured in experiments of competition between mixtures of mutant and parent strains on sprouts.