title: UNDERSTANDING NITROGEN LIMITATION IN AUREOCOCCUS ANOPHAGEFFERENS (PELAGOPHYCEAE) THROUGH cDNA AND qRT-PCR ANALYSIS(1).
abstract: Brown tides of the marine pelagophyte Aureococcus anophagefferens Hargraves et Sieburth have been investigated extensively for the past two decades. Its growth is fueled by a variety of nitrogen (N) compounds, with dissolved organic nitrogen (DON) being particularly important during blooms. Characterization of a cDNA library suggests that A. anophagefferens can assimilate eight different forms of N. Expression of genes related to the sensing, uptake, and assimilation of inorganic and organic N, as well as the catabolic process of autophagy, was assayed in cells grown on different N sources and in N-limited cells. Growth on nitrate elicited an increase in the relative expression of nitrate and ammonium transporters, a nutrient stress-induced transporter, and a sensory kinase. Growth on urea increased the relative expression of a urea and a formate/nitrite transporter, while growth on ammonium resulted in an increase in the relative expression of an ammonium transporter, a novel ATP-binding cassette (ABC) transporter and a putative high-affinity phosphate transporter. N limitation resulted in a 30- to 110-fold increase in the relative expression of nitrate, ammonium, urea, amino acid/polyamine, and formate/nitrite transporters. A. anophagefferens demonstrated the highest relative accumulation of a transcript encoding a novel purine transporter, which was highly expressed across all N sources. This finding suggests that purines are an important source of N for the growth of this organism and could possibly contribute to the initiation and maintenance of blooms in the natural environment.
authors.affiliation: Department of Geophysics, Stanford University, 397 Panama Mall, Stanford, California 94305, USADepartment of Plant Biology, The Carnegie Institution, 260 Panama Street, Stanford, California 94305, USAGenome Analysis Group Leibniz Institute for Age Research - Fritz Lipmann Institute, Beutenbergstr. 11, D-07745 Jena, GermanyDepartment of Geophysics, Stanford University, 397 Panama Mall, Stanford, California 94305, USADepartment of Plant Biology, The Carnegie Institution, 260 Panama Street, Stanford, California 94305, USA.
authors.forename: Gry Mine
authors.initials: GM
authors.lastname: Berg
authors.affiliation: Department of Geophysics, Stanford University, 397 Panama Mall, Stanford, California 94305, USADepartment of Plant Biology, The Carnegie Institution, 260 Panama Street, Stanford, California 94305, USAGenome Analysis Group Leibniz Institute for Age Research - Fritz Lipmann Institute, Beutenbergstr. 11, D-07745 Jena, GermanyDepartment of Geophysics, Stanford University, 397 Panama Mall, Stanford, California 94305, USADepartment of Plant Biology, The Carnegie Institution, 260 Panama Street, Stanford, California 94305, USA.
authors.forename: Jeff
authors.initials: J
authors.lastname: Shrager
authors.affiliation: Department of Geophysics, Stanford University, 397 Panama Mall, Stanford, California 94305, USADepartment of Plant Biology, The Carnegie Institution, 260 Panama Street, Stanford, California 94305, USAGenome Analysis Group Leibniz Institute for Age Research - Fritz Lipmann Institute, Beutenbergstr. 11, D-07745 Jena, GermanyDepartment of Geophysics, Stanford University, 397 Panama Mall, Stanford, California 94305, USADepartment of Plant Biology, The Carnegie Institution, 260 Panama Street, Stanford, California 94305, USA.
authors.forename: Gernot
authors.initials: G
authors.lastname: Glöckner
authors.affiliation: Department of Geophysics, Stanford University, 397 Panama Mall, Stanford, California 94305, USADepartment of Plant Biology, The Carnegie Institution, 260 Panama Street, Stanford, California 94305, USAGenome Analysis Group Leibniz Institute for Age Research - Fritz Lipmann Institute, Beutenbergstr. 11, D-07745 Jena, GermanyDepartment of Geophysics, Stanford University, 397 Panama Mall, Stanford, California 94305, USADepartment of Plant Biology, The Carnegie Institution, 260 Panama Street, Stanford, California 94305, USA.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Arrigo
authors.affiliation: Department of Geophysics, Stanford University, 397 Panama Mall, Stanford, California 94305, USADepartment of Plant Biology, The Carnegie Institution, 260 Panama Street, Stanford, California 94305, USAGenome Analysis Group Leibniz Institute for Age Research - Fritz Lipmann Institute, Beutenbergstr. 11, D-07745 Jena, GermanyDepartment of Geophysics, Stanford University, 397 Panama Mall, Stanford, California 94305, USADepartment of Plant Biology, The Carnegie Institution, 260 Panama Street, Stanford, California 94305, USA.
authors.forename: Arthur R
authors.initials: AR
authors.lastname: Grossman
keywords: Aureococcus anophagefferens; amino acid/polyamine transporter; ammonium transporter; formate/nitrite transporter; gene expression; nitrate transporter; nitrogen limitation; picoeukaryote; purine transporter; urea transporter