The role of l-arabinose metabolism for Escherichia coli O157:H7 in edible plants

• Published in: Microbiology (Society for General Microbiology) Vol. 167; no. 7
• Main Authors: Crozier, Louise, Marshall, Jacqueline, Holmes, Ashleigh, Wright, Kathryn Mary, Rossez, Yannick, Merget, Bernhard, Humphris, Sonia, Toth, Ian, Jackson, Robert Wilson, Holden, Nicola Jean
• Format: Journal Article
• Language: English
• Published: England Microbiology Society 01.07.2021
• Subjects: Arabinose - metabolism; Bacteriology; Biochemistry, Molecular Biology; Botanics; Carrier Proteins - genetics; Carrier Proteins - metabolism; Colony Count, Microbial; Escherichia coli O157 - genetics; Escherichia coli O157 - growth & development; Escherichia coli O157 - metabolism; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Food Microbiology; Genomics; Lactuca - microbiology; Life Sciences; Microbiology and Parasitology; Phosphotransferases (Alcohol Group Acceptor) - genetics; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Plant Microbiology and Soil Health; Plants, Edible - microbiology; Spinacia oleracea - microbiology; Vegetal Biology; food safety; plant-microbe interactions; bacterial pathogens; vegetables; plant cell wall degrading enzymes
• ISSN: 1465-2080; 1350-0872; 1465-2080
• DOI: 10.1099/MIC.0.001070

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 pectolytic micro-organisms such as via pectin and hemicellulose degrading enzymes. However, not all plant-associated microbes encode cell-wall-degrading enzymes, yet can metabolize l-arabinose, raising questions about their use of and access to the glycan in plants. Therefore, we examined l-arabinose metabolism in the food-borne pathogen O157:H7 (isolate Sakai) during its colonization of plants. l-arabinose metabolism ( ) and transport ( ) genes were activated at 18 °C by l-arabinose and expressed over prolonged periods . Although deletion of did not impact the colonization ability of O157:H7 (Sakai) on spinach and lettuce plants (both associated with STEC outbreaks), was induced on exposure to spinach cell-wall polysaccharides. Furthermore, debranched and arabinan oligosaccharides induced metabolism gene expression , and stimulated modest proliferation, while immobilized pectin did not. Thus, O157:H7 (Sakai) can utilize pectin/AGP-derived l-arabinose as a metabolite. Furthermore, it differs fundamentally in gene organization, transport and regulation from the related pectinolytic species , reflective of distinct plant-associated lifestyles.