Poster: Genomics Resources

Abs # 932: Genome analysis of Galdieria sulphuraria - a unique unicellular thermo-acidophilic photosynthetic microorganism

Presenter:	Weber, Andreas , aweber@msu.edu
Authors	Weber, Andreas  (A) (D)  Zimmermann, Marc  (A)   Oesterheldt, Christine  (C) (B)  Gross, Wolfgang  (B)   Jamai, Aziz  (E) (D)  Garavito, Michael M (A)   Benning, Christoph  (A)
Affiliations:	(A): Michigan State University (B): Free University of Berlin, Germany (C): Catholic University of Leuven, Belgium (D): University of Cologne, Germany (E): University of Southern Illinois at Carbondale
Web Site:	http://www.plantbiology.msu.edu/weber.shtml

Extreme environments are frequently dominated by prokaryotic extremophiles. However, the eukaryotic unicellular red micro-alga Galdieria sulphuraria can represent up to 90% of the biomass in extreme habitats such as hot sulfur springs (pH 0.05 to 4; temperatures up to 56°C). The gene sequences of this living fossil should reveal much about the evolution of modern eukaryotes. Galdieria thrives on more than 50 different sugars and sugar alcohols – evidence of a large repertoire of metabolic genes unequaled by few other organisms and a potentially rich source of thermophilic enzymes for biotechnology. Moreover, this organism tolerates toxic metals such as aluminum and nickel, suggesting a role in bioremediation. Proteins isolated from thermophiles frequently crystallize more readily, making Galdieria proteins valuable for structural biology studies. Finally, the high temperatures and low pH under which Galdieria photosynthesizes are at the extreme ranges for this process, thus this organism will likely prove a useful model for physical studies on the photosynthesis. We have initiated an EST project for Galdieria sulphuraria, to gain access to the rich source of genes involved in adaptation of this unique photosynthetic eukaryote to extreme conditions. As to date, we have sequenced more than 6,000 ESTs from two cDNA libraries that have been constructed from cells grown photoautotrophically or heterotrophically, respectively. We will present an analysis of the ESTs with emphasis on cDNAs encoding membrane transporters and enzymes involved in carbohydrate and lipid metabolism. In addition, we will report on an initial functional study of a plastid inner envelope membrane transporter from Galdieria sulphuraria.