DIVERSITY OF DIATOM IRON METABOLISM GENES REVEALED THROUGH WHOLE TRANSCRIPTOME SEQUENCING
Ferroproteins evolved in Earth's early oceans, taking advantage of iron's availability and superior redox capabilities. The rise of oxygenic photosynthesis led to changes in oceanic chemistry, including greatly decreased concentrations of bioavailable iron, making iron one of the primary limiting nutrients in the open ocean. Marine phytoplankton have evolved several adaptive strategies to compensate for this scarcity. Here we present a comparative analysis of the molecular repertoire utilized by diatoms to respond to variability in iron availability. We utilize sequence data provided by the MMETSP (http://marinemicroeukaryotes.org/), which includes over 40 diatom transcriptomes, to test previous hypotheses of iron metabolism with improved resolution and breadth of organismal diversity. We show that the iron storage protein ferritin is actively transcribed in the majority of diatom species queried, including radial and multipolar centrics. Phylogenetic analysis reveals a monophyletic diatom clade with distinctly diverged clusters. A majority of diatom species express the electron carrier flavodoxin, whereas plastocyanin is only sporadically expressed among the centric and pennate transcriptomes. Diatoms also possess an arsenal of superoxide dismutase isozymes, including a putative nickel superoxide dismutase.
Groussman, R. D., University of Washington, USA, email@example.com
Parker, M. S., University of Washington, USA, firstname.lastname@example.org
Armbrust, E. V., University of Washington, USA, email@example.com
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