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D 4 - Uwe Maier

Diatoms and their response to phosphate limitation

Prof. Dr. Uwe Maier
Philipps-Universität Marburg, Faculty of Biology

Karl-von-Frisch-Straße 8
35043 Marburg

Phone: +49 - 6421 - 2821543

Research summary

Phosphorus is an essential element in all forms of life. In aquatic environments phosphorus is predominantly available as phosphate. Algae, the organisms studied in the application, have to strictly regulate their phosphate homoeostasis. In the project applied here, we would like to study how diatoms, ecologically important primary biomass producers, manage fluctuating phosphate concentrations in the ocean. We have already shown that secreted alkaline phosphatases (AKP) are important players in response to phosphate availability. Notably, the regulation patterns of two studied members of the AKPs are different; only for one of them expression is correlated with phosphate concentrations.

We would like to study in more detail how diatoms try to overcome sinks of available phosphate. For that we plan to investigate the expression, secretion and the accompanied regulation of a total of seven phosphatases. In parallel we inspect the medium for other components secreted under phosphate limitation, which will be subsequently characterized as well. Targeting of some putative factors involved in phosphate metabolism might involve mechanisms, which fine regulates secretion. In order to study this, targeting mechanisms will be studied. Cells can store phosphate under non-limiting conditions. However, the putative phosphate stores or compartments are not known for diatoms and will be identified in our studies. In order to design diatom strains that can be used to study the physiological responses to phosphate limitation, we will establish TALEN-mediated genome editing to precisely eliminate important factors. Altogether, our approach will highlight important cellular responses to phosphate stress on a molecular level in diatoms.