title: A Genetic and Chemical Perspective on Symbiotic Recruitment of Cyanobacteria of the GenusNostocinto the Host PlantBlasia pusillaL.
abstract: LiverwortBlasia pusilla L.recruits soil nitrogen-fixing cyanobacteria of genusNostocas symbiotic partners. In this work we comparedNostoccommunity composition inside the plants and in the soil around them from two distant locations in Northern Norway. STRR fingerprinting and 16S rDNA phylogeny reconstruction showed a remarkable local diversity among isolates assigned to severalNostocclades. An extensive web of negative allelopathic interactions was recorded at an agricultural site, but not at the undisturbed natural site. The cell extracts of the cyanobacteria did not show antimicrobial activities, but four isolates were shown to be cytotoxic to human cells. The secondary metabolite profiles of the isolates were mapped by MALDI-TOF MS, and the most prominent ions were further analyzed by Q-TOF for MS/MS aided identification. Symbiotic isolates produced a great variety of small peptide-like substances, most of which lack any record in the databases. Among identified compounds we found microcystin and nodularin variants toxic to eukaryotic cells. Microcystin producing chemotypes were dominating as symbiotic recruits but not in the free-living community. In addition, we were able to identify several novel aeruginosins and banyaside-like compounds, as well as nostocyclopeptides and nosperin.
authors.affiliation: Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT-The Arctic University of Norway Tromsø, Norway.
authors.forename: Anton
authors.initials: A
authors.lastname: Liaimer
authors.affiliation: Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, UiT-The Arctic University of Norway Tromsø, Norway.
authors.forename: John B
authors.initials: JB
authors.lastname: Jensen
authors.affiliation: Department of Microbiology, Institute for Biochemistry and Biology, University of Potsdam Potsdam, Germany.
authors.forename: Elke
authors.initials: E
authors.lastname: Dittmann
keywords: Blasia; Cyanobacteria; Nostoc; allelopathy; secondary metabolites; symbiosis