ABSTRACT

Photosynthetic bacteria convert light into chemical energy for the subsequent fixation of carbon dioxide from the atmosphere into biomass. These organisms account for >50% of all photosynthesis, and thus they insure the continued existence of life on Earth. In this study, the genome sequences of 15 photosynthetic bacteria will be completed, annotated and compared. Green Sulfur Bacteria (GSB) are major primary producers in anoxic environments, where they contribute significantly to the biogeochemical cycling of carbon, nitrogen, and sulfur on Earth. Until recently, genome information was only available for Chlorobium tepidum, a possibly atypical organism from a sulfide-rich hot spring. The Joint Genome Institute (JGI-DOE) has completed draft sequences for eight GSB, and a ninth GSB genome will be sequenced in 2005. JGI-DOE will also produce high-quality draft sequences for seven members of the Chloroflexi, six of which are Filamentous Anoxygenic Phototrophs (FAPs; formerly, green gliding/non-sulfur bacteria). Only an incomplete draft sequence for one FAP, Chloroflexus aurantiacus is currently available. Recent studies suggest that FAPs are physiologically diverse and widely distributed in nature. Newly described isolates can fix carbon using different pathways, fix nitrogen, and oxidize sulfide and possibly ferrous iron and other metals. FAPs are important but poorly characterized components of terrestrial, freshwater and saline environments, and whole-genome analyses will provide many new insights into their properties.

Many scientists are currently studying photoautotrophic metabolism, the mechanisms and origins of photosynthesis, and the evolutionary relationships among photoautotrophs. These issues will be directly addressed in this study through whole-genome sequencing and subsequent comparative bioinformatic analyses of the data. Since it will be the largest and most comprehensive database ever assembled for both GSB and FAPs, the data obtained in this study will have very broad impact. The finished sequences will be deposited in public databases, and these data, as well as the automatic and manual annotation data, will also be made available via a publicly accessible website. Two postdoctoral scientists and four undergraduate researchers will be trained during the execution of this research program. The PI and Co-PI will organize a course for advanced undergraduates and graduate students that will provide both passive and active learning experiences in Microbial Genomics and Bioinformatics. This course will fill an existing void in the microbiology and bioinformatics curriculum at The Pennsylvania State University.

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