Abstract
Genomes of the month
This month, four genomes from two different species will be discussed. The first organism, Rhodopseudomonas palustris, is a metabolic fox, in that it can do many different things. R. palustris is one of the most metabolically versatile bacteria known it can grow utilizing any one of the four modes of metabolism that support life. In contrast, the three different Prochlorococcus marinus isolates are perhaps more like metabolic hedgehogs' in that they can do only one thing, but they do it very well. P. marinus requires only light, CO2 and inorganic materials to live, and the three different genomes reflect adaptation to different ecological environments, in terms of wavelength and intensity of available light.
R. palustris is a purple photosynthetic bacterium, belonging to the α-Proteobacteria. R. palustris can obtain energy from light, inorganic compounds or organic compounds, allowing survival and growth under a wide range of conditions. The genome of R. palustris strain CGA009 consists of a circular chromosome of about 5·46 Mbp in length, which is slightly below the average size (5·6 Mbp) for free-living α-Proteobacteria (see Fig. 1). The genome encodes 4836 predicted genes (see for a detailed list of genes), including all genes necessary for growth with CO2 as the sole carbon source; about 15 % of the genome is devoted to transport (Larimer et al., 2004). R. palustris is ideally suited for use as a biocatalyst and it might be possible to bioengineer this organism to produce large amounts of H2 from plant biomass (Larimer et al., 2004).