title: A common theme in extracellular fluids of beetles: extracellular superoxide dismutases crucial for balancing ROS in response to microbial challenge.
abstract: Extracellular Cu/Zn superoxide dismutases (SODs) are critical for balancing the level of reactive oxygen species in the extracellular matrix of eukaryotes. In the present study we have detected constitutive SOD activity in the haemolymph and defensive secretions of different leaf beetle species. Exemplarily, we have chosen the mustard leaf beetle, Phaedon cochleariae, as representative model organism to investigate the role of extracellular SODs in antimicrobial defence. Qualitative and quantitative proteome analyses resulted in the identification of two extracellular Cu/Zn SODs in the haemolymph and one in the defensive secretions of juvenile P. cochleariae. Furthermore, quantitative expression studies indicated fat body tissue and defensive glands as the main synthesis sites of these SODs. Silencing of the two SODs revealed one of them, PcSOD3.1, as the only relevant enzyme facilitating SOD activity in haemolymph and defensive secretions in vivo. Upon challenge with the entomopathogenic fungus, Metarhizium anisopliae, PcSOD3.1-deficient larvae exhibited a significantly higher mortality compared to other SOD-silenced groups. Hence, our results serve as a basis for further research on SOD regulated host-pathogen interactions. In defensive secretions PcSOD3.1-silencing affected neither deterrent production nor activity against fungal growth. Instead, we propose another antifungal mechanism based on MRJP/yellow proteins in the defensive exudates.
authors.affiliation: Department of Bioorganic Chemistry, Max-Planck-Institute for Chemical Ecology, Hans-Knoell-Str. 8, D-07745 Jena, Germany.
authors.forename: René R
authors.initials: RR
authors.lastname: Gretscher
authors.affiliation: Department of Bioorganic Chemistry, Max-Planck-Institute for Chemical Ecology, Hans-Knoell-Str. 8, D-07745 Jena, Germany.
authors.forename: Priska E
authors.initials: PE
authors.lastname: Streicher
authors.affiliation: Department of Bioorganic Chemistry, Max-Planck-Institute for Chemical Ecology, Hans-Knoell-Str. 8, D-07745 Jena, Germany.
authors.forename: Anja S
authors.initials: AS
authors.lastname: Strauß
authors.affiliation: Research Group Mass Spectrometry/Proteomics, Max Planck Institute for Chemical Ecology, Jena, Germany.
authors.forename: Natalie
authors.initials: N
authors.lastname: Wielsch
authors.affiliation: Department of Bioorganic Chemistry, Max-Planck-Institute for Chemical Ecology, Hans-Knoell-Str. 8, D-07745 Jena, Germany.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Stock
authors.affiliation: Department of Bioorganic Chemistry, Max-Planck-Institute for Chemical Ecology, Hans-Knoell-Str. 8, D-07745 Jena, Germany.
authors.forename: Ding
authors.initials: D
authors.lastname: Wang
authors.affiliation: Department of Bioorganic Chemistry, Max-Planck-Institute for Chemical Ecology, Hans-Knoell-Str. 8, D-07745 Jena, Germany.
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Boland
authors.affiliation: Department of Bioorganic Chemistry, Max-Planck-Institute for Chemical Ecology, Hans-Knoell-Str. 8, D-07745 Jena, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Burse
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000254:growth & development / Q000276:immunology* / Q000382:microbiology*; D020868:Gene Silencing; D006458:Hemolymph / Q000201:enzymology* / Q000276:immunology*; D007814:Larva / Q000276:immunology / Q000382:microbiology; D052981:Metarhizium / Q000276:immunology* / Q000472:pathogenicity; D017382:Reactive Oxygen Species / Q000378:metabolism*; D000072105:Superoxide Dismutase-1 / Q000235:genetics / Q000378:metabolism*; D016019:Survival Analysis
chemical_list: D017382:Reactive Oxygen Species; D000072105:Superoxide Dismutase-1