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UNDERSTANDING NITROGEN LIMITATION IN AUREOCOCCUS ANOPHAGEFFERENS (PELAGOPHYCEAE) THROUGH cDNA AND qRT-PCR ANALYSIS1
Article first published online: 17 SEP 2008
© 2008 Phycological Society of America
Journal of Phycology
Volume 44, Issue 5, pages 1235–1249, October 2008
How to Cite
Berg, G. M., Shrager, J., Glöckner, G., Arrigo, K. R. and Grossman, A. R. (2008), UNDERSTANDING NITROGEN LIMITATION IN AUREOCOCCUS ANOPHAGEFFERENS (PELAGOPHYCEAE) THROUGH cDNA AND qRT-PCR ANALYSIS. Journal of Phycology, 44: 1235–1249. doi: 10.1111/j.1529-8817.2008.00571.x
Received 6 September 2007. Accepted 21 March 2008.
- Issue published online: 8 OCT 2008
- Article first published online: 17 SEP 2008
- amino acid/polyamine transporter;
- ammonium transporter;
- Aureococcus anophagefferens;
- formate/nitrite transporter;
- gene expression;
- nitrate transporter;
- nitrogen limitation;
- purine transporter;
- urea transporter
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.