title: Acquisition of iron by Trichodesmium and associated bacteria in culture.
abstract: Trichodesmium colonies contain an abundant microbial consortium that is likely to play a role in nutrient cycling within the colony. This study used laboratory cultures of Trichodesmium and two genome-sequenced strains of bacteria typical of Trichodesmium-associated microbes to develop an understanding of the cycling of iron, a potentially limiting micronutrient, within Trichodesmium colonies. We found that the ferric siderophores desferrioxamine B and aerobactin were not readily bioavailable to Trichodesmium, relative to ferric chloride or citrate-associated iron. In contrast, the representative bacterial strains we studied were able to acquire iron from all of the iron sources, implying that naturally occurring Trichodesmium-associated bacteria may be capable of utilizing a more diverse array of iron sources than Trichodesmium. From the organism-specific uptake data collected in this study, a theoretical Trichodesmium colony was designed to model whole colony iron uptake. The bacteria accounted for most (> 70%) of the iron acquired by the colony, highlighting the importance of determining organism-specific uptake in a complex environment. Our findings suggest that, although they may share the same micro-environment, Trichodesmium and its colony-associated microbial cohort may differ substantially in terms of iron acquisition strategy.
authors: Geoscience Research Division, Scripps Institution of Oceanography, La Jolla, California 92093, USA.
authors: Kelly L
authors: KL
authors: Roe
authors: Katherine
authors: K
authors: Barbeau
authors: Elizabeth L
authors: EL
authors: Mann
authors: Margo G
authors: MG
authors: Haygood
mesh_terms: D002712:Chlorides / Q000378:metabolism; D000458:Cyanobacteria / Q000254:growth & development / Q000378:metabolism*; D003676:Deferoxamine / Q000378:metabolism*; D005290:Ferric Compounds / Q000378:metabolism; D006877:Hydroxamic Acids / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D017262:Siderophores / Q000378:metabolism*
chemical_list: D002712:Chlorides; D005290:Ferric Compounds; D006877:Hydroxamic Acids; D017262:Siderophores; C031819:aerobactin; D007501:Iron; D003676:Deferoxamine; C024555:ferric chloride