Plant, Animal & Microbe Genomes X Conference Plant, Animal & Microbe Genomes X ConferenceJanuary 12-16, 2002
Town & Country Convention Center
San Diego, CA
Session: Microbe Session Lecture
Rhodopseudomonas palustris is a very successful photosynthetic bacterium that can be found in virtually any temperate soil or water sample on earth. It is among the most metabolically versatile of known bacteria and has many alternative ways of acquiring carbon and nitrogen and of generating energy. It is also robust and able to survive for long periods of time with very few nutrients. Each of these aspects of the biology of Rps. palustris is reflected in its 5.49 Mb genome. Rps. palustris has a large cluster of photosynthesis genes and a collection of additional genes that encode light-responsive proteins. It has genes for the catabolism of diverse kinds of carbon sources, including lignin monomers, sugars, fatty acids and dicarboxylic acids. It encodes two different carbon dioxide fixation enzymes and three different nitrogen fixation enzymes, each with a different transition metal at its active site. It has genes to carry out anaerobic respiration using nitric oxide and nitrite as electron acceptors and it has genes for thiosulfate oxidation and hydrogen oxidation. It is obvious that an organism with this degree of metabolic versatility must have a great deal of traffic with its environment. This is reflected by a very large number of transport systems, especially transport systems for iron. Genes for at least seven multidrug resistance efflux pumps and the presence of a cluster of genes for polyketide biosynthesis may help explain why Rps. palustris survives so well in most soil and water environments.