GENOME EVOLUTION · Tracing the evolution of alpha-proteaobacterial genomes
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2008-03-01 → 2010-02-28
- EU contribution
- €166,488
- Participants
- 1
- Scheme
- EIF
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Results in brief
Final Activity and Management Report Summary - GENOME EVOLUTION (Tracing the evolution of alpha-proteaobacterial genomes)
Although invisible to the naked eye, bacteria have played important roles, not only for us, humans, but also at a larger scale: They drive fundamental biochemical processes that are crucial for sustaining life on planet Earth. One way to obtain fundamental insight in how bacteria drive these processes, is to study their genetic. During the past decennia, methods have been developed that allow for the elucidation of complete genomes of organisms, revealing all the genes encoded within it. The current study aims at gaining insight in a specific class of bacteria designated the alpha-proteobacteria, for the following reasons: (i) Alpha-proteobacteria are among the most ubiquitous and versatile bacteria currently known to man and, as such, they represent an evolutionary extremely successful group. In addition (ii), alpha-proteobacteria have been shown to interact with highly developed life, including us, humans. Some alpha-proteobacterial species are known causative agents of diseases and epidemics. Finally (iii), alpha-proteobacteria are interesting from an evolutionary point of view, as mitochondria, essential energy-generating organelles of eukaryotic cells, have emerged from an ancestral-type of alpha-proteobacterium. By studying the alpha-proteobacterial genomes, the current study has tried to gain insight in the genome evolution of alpha-proteobacteria, thereby revealing several interesting features. For example, the genome sequences of the alpha-proteobacterial SAR11 group, which are perhaps to most abundant life forms on the planet, were found to be exceptionally small, having been subjected to extreme genome reduction. Intriguingly, the SAR11 genomes were missing a number of genes involved in the maintenance of their genetic integrity. We argue that the absence of these genes, which were present in all other known alpha-proteobacterial species, might underlie their success in terms of overall abundance of this group of bacteria on the planet. In addition, our study focused on the identification of alpha-proteobacterial species that represented distant relatives to the ancestor of the mitochondria. In a so-called metagenomics approach, in which large amounts of environmental sequence data from the ocean surface waters was analysed, we managed to identify gene fragments that indeed might indeed belong to an alpha-proteobacterial species with a distant relationship to mitochondria.
Data: CORDIS, © European Union
Project objective
The microbial world remains largely unexplored. The goal of this project is to study microbial genome diversity and understand how the genomes of microbial pathogens evolve, using the alpha-proteobacteria as a model system. The alpha-proteobacteria are a bacterial subdivision of much interest from both a medical and an ecological standpoint. Many species establish chronic host-infections, with higher vertebrates (e.g. human, cattle and rodents) as well as with plants and insects. Well-known alpha-proteobacterial infections include trench fever, cat-scratch disease (Bartonella sp.) and formation of tumour-like structures in host tissues, such as in plants by Agrobacterium tumefaciens. Moreover, other alpha-proteobacterial species are known to establish tight symbiotic interactions with plants, such as is the case with the formation of root nodules that are involved nitrogen fixation. Furthermore, they represent a genetic group that is predominant in the environment, as suggested by environmental shotgun genome sequencing of the Sargasso Sea. Because of the broad diversity in genome sizes and structures, the alpha-proteobacteria offer an excellent model system for studies of the forces, mechanisms and rates whereby bacterial genomes evolve. At the date of this writing, more than 20 alpha-proteobacterial genomes have been completely sequenced, ranging in size from 1.1 to 9.1 Megabases, and many more will be available in the near future. The aim of this project is to study the evolution of the alpha-proteobacteria by analyzing their genomes, and as such gain insight in how specific alpha-proteobacterial lineages have evolved into the present-day pathogens and (endo)symbionts. This will be achieved by reconstructing ancestral alpha-proteobacterial genomes and to specifically study the flow of genes along the nodes towards the different pathogenic and symbiotic lineages, including the ultimate endosymbionts: the eukaryotic mitochondria.
Original text from CORDIS.
Participants
- UPPSALA UNIVERSITY · UPPSALACoordinatorSweden
Links
Data: CORDIS, © European Union