Plant Biology Research Profile: Dr. Marilyn J. Roossinck
Ph.D., Microbiology and Immunology, 1986, University of Colorado
Joined the Noble Foundation in 1991
- We are interested in virus evolution and ecology in host disease and health. We use plant and fungal viruses as model systems. The fundamental questions we are addressing are:
How and why would a virus become a pathogen?What is the role of viruses in natural systems?
What are the molecular mechanisms of virus evolution?
Cucumber mosaic virus
Our model viruses: We use Cucumber mosaic virus (CMV) as a model for many of our studies (Roossinck, 2001). CMV is a species in the genus Cucumovirus and the family Bromoviridae. CMV is a plus-sense RNA virus with a divided genome. It infects about 1200 species of plants, which is the broadest host range of any known virus. RNA 1 (about 3400 nt) encodes the 1a protein that is involved in replication and has the motifs of a methyl transferase (presumed to provide the 5' cap structure to the genomic RNAs) and a helicase. RNA 2 (about 3000 nt) encodes the 2a protein with a classic GDD RNA dependent RNA polymerase motif, and the 2b protein that is involved in suppression of host gene silencing. RNA 3 (about 2200 nt) encodes the movement protein, required for cell-to-cell and systemic movement, and the coat protein that encapsidates the RNA. The open reading frames of CMV exhibit a modular type of evolution (Roossinck, 2002). Sometimes CMV strains harbor a parasitic RNA called the satellite RNA (satRNA). The satRNAs are small (about 330-400 nt) and do not appear to encode any proteins. They are highly structured (Rodríguez-Alvarado and Roossinck, 1997), have a variety of effects on the virus and the host, and make excellent reporters for disease and evolution.
Other models we use are Cowpea chlorotic mottle virus, a relative of CMV, and an array of fungal viruses.
From The Microbeworld Radio Show, which is a daily, 90-second, syndicated radio feature on microbiology. More information >
2/25/2008 (mp3 file)
5,000 virus genome project: A scientist who believes virusesÂ’ bad reputation for causing disease is undeserved is on a mission to analyze the genetic sequences of 5,000 viruses in hopes of restoring their good names.
12/07/2007 (mp3 file)
A plant, a fungus, and a virus: Most people consider viruses to be a bad thing, but one type of grass in Yellowstone National Park needs a virus to survive the extreme heat.