title: Response of Medicago truncatula seedlings to colonization by Salmonella enterica and Escherichia coli O157:H7.
abstract: Disease outbreaks due to the consumption of legume seedlings contaminated with human enteric bacterial pathogens like Escherichia coli O157:H7 and Salmonella enterica are reported every year. Besides contaminations occurring during food processing, pathogens present on the surface or interior of plant tissues are also responsible for such outbreaks. In the present study, surface and internal colonization of Medicago truncatula, a close relative of alfalfa, by Salmonella enterica and Escherichia coli O157:H7 were observed even with inoculum levels as low as two bacteria per plant. Furthermore, expression analyses revealed that approximately 30% of Medicago truncatula genes were commonly regulated in response to both of these enteric pathogens. This study highlights that very low inoculum doses trigger responses from the host plant and that both of these human enteric pathogens may in part use similar mechanisms to colonize legume seedlings.
authors.affiliation: Department of Agronomy, University of Wisconsin-Madison, Madison Madison, Wisconsin, United States of America.
authors.forename: Dhileepkumar
authors.initials: D
authors.lastname: Jayaraman
authors.affiliation: Department of Agronomy, University of Wisconsin-Madison, Madison Madison, Wisconsin, United States of America.
authors.forename: Oswaldo
authors.initials: O
authors.lastname: Valdés-López
authors.affiliation: Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
authors.forename: Charles W
authors.initials: CW
authors.lastname: Kaspar
authors.affiliation: Department of Agronomy, University of Wisconsin-Madison, Madison Madison, Wisconsin, United States of America.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Ané
mesh_terms: D015169:Colony Count, Microbial; D060026:Endophytes / Q000254:growth & development; D019453:Escherichia coli O157 / Q000254:growth & development*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D063990:Gene Ontology; D017343:Genes, Plant / Q000235:genetics; D046913:Medicago truncatula / Q000235:genetics / Q000382:microbiology*; D020411:Oligonucleotide Array Sequence Analysis; D018517:Plant Roots / Q000235:genetics / Q000382:microbiology; D019779:Salmonella enterica / Q000254:growth & development*; D036226:Seedlings / Q000235:genetics / Q000382:microbiology*; D013312:Stress, Physiological / Q000235:genetics