The Genetic Diversity of Broad-Host-Range Plasmids in Prokaryotes

Regents Of The University Of Idaho, Moscow ID

Investigators

Abstract

Plasmids are genetic elements that often carry antibiotic resistance factors, pollutant degradation genes or code for traits that are useful for their bacterial hosts. Because plasmids can transfer among different bacterial species, they play an important role in the ability of bacteria to degrade environmental contaminants and to become resistant to drugs used to treat infectious diseases of plants, animals and humans. However, little is known about the genetic structure of these mobile elements, the full range of functions that they encode, and the limits to which they can transfer to various organisms. To gain insight into the issues outlined above, this genome sequencing project will focus on the analysis of the genome sequences of 100 plasmids that have a broad host-range (also called BHR plasmids). The sequenced plasmids were obtained from soil, water, and sewage sludge samples from around the globe. The project includes finishing the sequencing and annotation of the plasmids, and then interpreting the sequence information to better understand the evolutionary history of plasmids, and their role in bacterial chromosome evolution and adaptation to new environments. The information collected during this project will add significant new data to the paltry plasmid sequence database that now exists, which is also skewed towards plasmids relevant to human infectious diseases. This study is unique, as it will constitute the first comprehensive expedition to discover the genetic traits encoded by BHR plasmids and to understand the genetic structure of these mobile elements and their role in gene transfer between chromosomes of bacteria. Moreover, the types of plasmids characterized will be extended beyond those that are found in human pathogens and easily cultivated bacteria. The knowledge gained will be of fundamental importance to understanding the evolution and adaptation of bacteria, and of practical significance in developing strategies to exploit plasmid encoded traits and in evaluating the risks associated with the introduction of genetically modified organisms into the environment. The genome sequences of 100 BHR plasmids will be made available to the science community through Genbank as well as through recently constructed plasmid databases. The project will integrate this research with educational programs by involving students from Idaho's undergraduate colleges and local high schools, with special emphasis on Native American and Hispanic students. Efforts to disseminate the work beyond the normal distribution channels will focus on Web delivery that will include several features designed to provide useful information for middle school through college students, their teachers and advisors as well as the public. These features will include innovative information graphics, audio and video podcasts focused on "Issues in Science", a frequently updated blog, and laboratory lesson examples to share with middle and high school teachers. This project will also enhance the careers of two women faculty in science.