This project will produce genome sequences for four plant-associated Burkholderia species: B. sp. PVA5, B. tuberum STM-678T, B. unamae MTI-641T, and B. sp. SRMrh-20. Pyrosequencing methodology from 454 will be used to sequence each of these genomes. These data will be used to compile a complete description of the genes contained in each bacterium, then analyzed for important physiological mechanisms for nitrogen fixation and compared to other nitrogen-fixing bacteria, particularly the phylogenetically distinct rhizobia.

For over a hundred years, members of the rhizobia were known as the sole group of bacteria that could nodulate (intimately associate with a plant host) and fix nitrogen (providing nutrients for their plant host), a process of critical importance. Thus it is of intense interest to discover the genetic basis for the nitrogen fixing capacity of the Burkholderia. One strain to be sequenced, the novel species B. tuberum STM-678T, isolated in South Africa, acquired nodulation and nitrogen fixation mechanisms independently from other organisms. B. unamae MTI-641T and B. sp. SRMrh-20 represent different clades of plant associated nodulating nitrogen fixers (from Brazil and Mexico), and taken together these organisms will richly sample the genetic diversity of these organisms. The fourth strain to be sequenced, PVA5 (from Brazil), does not nodulate but enters the root by infection and may represent a new form of symbiosis, giving insight into the evolution of this important plant-microbe interaction. These plant-associated Burkholderia will also be examined for genes encoding enzymes in pathways for biocontrol and for soil remediation via the breakdown of xenobiotics. Lastly, the genomes will be compared to other sequenced Burkholderia genomes, particularly from pathogenic species, in order to shed light on the evolution of virulent microorganisms.

An international group of scientists (U.S., U.K., France, Germany, Brazil, Mexico,Taiwan) has been researching the plant-associated Burkholderia strains with regard to their phylogeny, their responses to the environment, and their interactions with plants. The selected organisms are the exact strains that are used in the experimental studies, and hence the genome will be of immense and immediate benefit to these pursuits.