

@article {2406,
	title = {{Exposure of Escherichia coli \{O157:H7\} to soil, manure, or water influences its survival on plants and initiation of plant defense response}},
	journal = {Food Microbiology},
	volume = {38},
	year = {2014},
	pages = {87{\textendash}92},
	abstract = {This study evaluated whether growth medium or exposure conditions influence the production of capsular polysaccharides \{(CPS)\} by Escherichia coli \{O157:H7,\} and whether changes in \{CPS\} impact plant defense responses, consequently affecting survival on plants. E.\~{}coli \{O157:H7\} grown in \{Luria{\textendash}Bertani\} \{(LB)\} broth supplemented with manure extracts showed an approximately 58\% increase in \{CPS\} production compared to cells grown in \{LB\} medium alone. Levels of \{CPS\} were significantly higher for E.\~{}coli \{O157:H7\} cells exposed to soil or manure extracts as compared to the non-exposed \{LB\} cultured control. Arabidopsis thaliana plants expressing $\beta$-glucuronidase \{(GUS)\} under the control of the $\beta$-1,3-glucanase \{(BGL2)\} promoter were used to investigate whether E.\~{}coli \{O157:H7\} induces defense-related gene expression. Plants inoculated with E.\~{}coli \{O157:H7\} grown in \{LB\} containing manure extracts or cells exposed to manure extracts exhibited 3-fold and 2-fold lower \{GUS\} activity, respectively, suggesting a limited plant defense response compared to plants inoculated with cells grown in \{LB.\} On day 5 post inoculation the population of E.\~{}coli \{O157:H7\} grown in \{LB\} supplemented with manure on plants was significantly greater than the population of E.\~{}coli \{O157:H7\} grown in \{LB\} medium alone. E.\~{}coli \{O157:H7\} cells exposed to soil or manure exhibited greater survival on plants compared to \{LB-grown\} E.\~{}coli \{O157:H7.\} The results of this study underscore the need to consider medium composition and cultural conditions when conducting crop challenge studies.},
	doi = {10.1016/j.fm.2013.08.015},
	author = {Seo, Seungwook and Matthews, Karl R}
}
