TY - JOUR
T1 - The role of L-arabinose metabolism for Escherichia coli O157:H7 in edible plants
AU - Crozier, Louise
AU - Marshall, Jacqueline
AU - Holmes, Ashleigh
AU - Wright, Kathryn Mary
AU - Rossez, Yannick
AU - Merget, Bernhard
AU - Humphris, Sonia
AU - Toth, Ian
AU - Jackson, Robert Wilson
AU - Holden, Nicola Jean
PY - 2021/7/28
Y1 - 2021/7/28
N2 - Arabinose is a major plant aldopentose in the form of arabinans complexed in cell wall polysaccharides or glycoproteins(AGP), but comparatively rare as a monosaccharide. l-arabinose is an important bacterial metabolite, accessed by pectolyticmicro-organisms such as Pectobacterium atrosepticum via pectin and hemicellulose degrading enzymes. However, not all plantassociated microbes encode cell-wall-degrading enzymes, yet can metabolize l-arabinose, raising questions about their useof and access to the glycan in plants. Therefore, we examined l-arabinose metabolism in the food-borne pathogen Escherichiacoli O157:H7 (isolate Sakai) during its colonization of plants. l-arabinose metabolism (araBA) and transport (araF) genes wereactivated at 18°C in vitro by l-arabinose and expressed over prolonged periods in planta. Although deletion of araBAD did notimpact the colonization ability of E. coli O157:H7 (Sakai) on spinach and lettuce plants (both associated with STEC outbreaks),araA was induced on exposure to spinach cell-wall polysaccharides. Furthermore, debranched and arabinan oligosaccharidesinduced ara metabolism gene expression in vitro, and stimulated modest proliferation, while immobilized pectin did not. Thus,E. coli O157:H7 (Sakai) can utilize pectin/AGP-derived l-arabinose as a metabolite. Furthermore, it differs fundamentally in aragene organization, transport and regulation from the related pectinolytic species P. atrosepticum, reflective of distinct plantassociated lifestyles.
AB - Arabinose is a major plant aldopentose in the form of arabinans complexed in cell wall polysaccharides or glycoproteins(AGP), but comparatively rare as a monosaccharide. l-arabinose is an important bacterial metabolite, accessed by pectolyticmicro-organisms such as Pectobacterium atrosepticum via pectin and hemicellulose degrading enzymes. However, not all plantassociated microbes encode cell-wall-degrading enzymes, yet can metabolize l-arabinose, raising questions about their useof and access to the glycan in plants. Therefore, we examined l-arabinose metabolism in the food-borne pathogen Escherichiacoli O157:H7 (isolate Sakai) during its colonization of plants. l-arabinose metabolism (araBA) and transport (araF) genes wereactivated at 18°C in vitro by l-arabinose and expressed over prolonged periods in planta. Although deletion of araBAD did notimpact the colonization ability of E. coli O157:H7 (Sakai) on spinach and lettuce plants (both associated with STEC outbreaks),araA was induced on exposure to spinach cell-wall polysaccharides. Furthermore, debranched and arabinan oligosaccharidesinduced ara metabolism gene expression in vitro, and stimulated modest proliferation, while immobilized pectin did not. Thus,E. coli O157:H7 (Sakai) can utilize pectin/AGP-derived l-arabinose as a metabolite. Furthermore, it differs fundamentally in aragene organization, transport and regulation from the related pectinolytic species P. atrosepticum, reflective of distinct plantassociated lifestyles.
KW - Bacterial pathogens
KW - Food safety
KW - Plant cell wall degrading enzymes
KW - Plant-microbe interactions
KW - Vegetables
UR - http://www.scopus.com/inward/record.url?scp=85112712419&partnerID=8YFLogxK
U2 - 10.1099/mic.0.001070
DO - 10.1099/mic.0.001070
M3 - Article
C2 - 34319868
SN - 1350-0872
VL - 167
JO - Microbiology
JF - Microbiology
IS - 7
M1 - 001070
ER -