A combined public and private team of microbiologists has completed sequencing the genome of the plant pathogen Agrobacterium tumefaciens. This bacterium has become an essential tool for plant research and biotechnology, and researchers continue to seek ways of harnessing its infectious processes to bio-engineer plants for societal benefit.
The journal Science in its issue of December 14 features the A. tumefaciens milestone in a cover story on agrobacterium research. A. tumefaciens also serves as a practical model for research into other pathogens that affect both plants and animals.
With principal support from the National Science Foundation (NSF), researchers at the University of Washington (UW) partnered with the E.I. du Pont de Nemours Company to sequence the genome. Other collaborators include researchers from The Institute for Genomic Research, SRI International and the University of Campinas in Brazil. The resulting data will be available publicly for use by other scientists.
Scientists use A. tumefaciens to generate transgenic plants in both academic and industrial settings. Having access to the genome sequences should help researchers improve the efficiency of this tool and broaden the host range to which segments of transgenic DNA (called T-DNA) segments can be effectively transferred.
"Knowledge gleaned from the genome sequence of A. tumefaciens could be key to understanding the evolution of plant-microbe relationships," said UW microbiologist Derek Wood, lead author of the Science article. "This agrobacterium and its cousin, Sinorhizobium meliloti, will let us study the separation of closely related organisms into divergent pathogenic and symbiotic lifestyles. A. tumefaciens is a natural genetic engineer that transfers selected genes into plant cells during the disease process, causing plants to synthesize compounds useful to the bacterium. We can tailor that same process to introduce desirable changes."
One indication of the importance attached to A. tumefaciens is that the DuPont company had completed a "rough draft" of the sequence for proprietary purposes. Maryanna Henkart, director of the NSF Division of Molecular and Cellular Biosciences, said that the university researchers' cooperation with DuPont was important to avoid duplication of effort.
"Broad access to genome data is key to so much progress in science," said Henkart. "A major issue in genomics is how the public and private sectors can collaborate, with mutual benefit. NSF is pleased to have sponsored a part of this innovative arrangement."
Eugene Nester, a UW professor of microbiology and long-time leader in A. tumefaciens research, originated the agreement with DuPont. The company promised to make its data public if NSF funded sequencing of the remaining genome portions. That effort took less than one year following an NSF award in late 2000 to UW Genome Center director Maynard Olson.
"This is the only case in nature where DNA and proteins from bacteria are transferred into plants or animals," said Nester. "At one time, many scientists said it couldn't be done. But in fact, normal tobacco plants contain the A. tumefaciens DNA."