title: Escherichia coli K-12 pathogenicity in the pea aphid, Acyrthosiphon pisum, reveals reduced antibacterial defense in aphids.
abstract: To better understand the molecular basis underlying aphid immune tolerance to beneficial bacteria and immune defense to pathogenic bacteria, we characterized how the pea aphid Acyrthosiphon pisum responds to Escherichia coli K-12 infections. E. coli bacteria, usually cleared in the hemolymph of other insect species, were capable of growing exponentially and killing aphids within a few days. Red fluorescence protein expressing E. coli K-12 laboratory strain multiplied in the aphid hemolymph as well as in the digestive tract, resulting in death of infected aphids. Selected gene deletion mutants of the E. coli K-12 predicted to have reduced virulence during systemic infections showed no difference in either replication or killing rate when compared to the wild type E. coli strain. Of note, however, the XL1-Blue E. coli K-12 strain exhibited a significant lag phase before multiplying and killing aphids. This bacterial strain has recently been shown to be more sensitive to oxidative stress than other E. coli K-12 strains, revealing a potential role for reactive oxygen species-mediated defenses in the otherwise reduced aphid immune system.
authors.affiliation: Department of Biology, Emory University, O. Wayne Rollins Research Center, Atlanta, GA 30322, USA. boran.altincicek@uni-bonn.de
authors.forename: Boran
authors.initials: B
authors.lastname: Altincicek
authors.forename: Bas
authors.initials: B
authors.lastname: Ter Braak
authors.forename: Alice M
authors.initials: AM
authors.lastname: Laughton
authors.forename: Klas I
authors.initials: KI
authors.lastname: Udekwu
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Gerardo
mesh_terms: D000818:Animals; D001042:Aphids / Q000235:genetics / Q000276:immunology / Q000382:microbiology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology; D004927:Escherichia coli Infections / Q000382:microbiology; D048168:Escherichia coli K12 / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000235:genetics / Q000276:immunology; D041981:Gastrointestinal Tract / Q000382:microbiology; D006458:Hemolymph / Q000382:microbiology; D054884:Host-Pathogen Interactions / Q000276:immunology*; D007113:Immunity, Innate / Q000502:physiology*; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology; D018272:Porins / Q000235:genetics / Q000276:immunology; D011494:Protein Kinases / Q000235:genetics / Q000276:immunology; D017382:Reactive Oxygen Species / Q000276:immunology*; D017384:Sequence Deletion / Q000276:immunology; D013559:Symbiosis / Q000276:immunology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C113724:OmpC protein; D018272:Porins; D017382:Reactive Oxygen Species; C078167:OMPA outer membrane proteins; D011494:Protein Kinases; C065271:arcB protein, E coli