Garbelotto said that other scientists hypothesized that gene regulation has an effect on plant pathogens, based on the evolutionary rates of portions of the genome that are known to have an effect on gene regulation.
"Our work provides the concrete evidence those hypotheses were correct," he said.
Researchers showed that genetically identical strains of the sudden oak death pathogen isolated from different plant hosts were strikingly different in their virulence and their ability to proliferate.
They also demonstrated that these traits were maintained long after they had been isolated from their hosts.
"We found that an identical strain placed in two different plant hosts will undergo distinct changes that will persistently affect the strain's virulence and fitness," said Takao Kasuga, a molecular geneticist with the USDA ARS and the lead author of the paper.
The implications for disease control are significant.
Scientists say that it may not be enough to know what strain of pathogens they are dealing with in order to make treatment decisions; it also may be necessary to know how the pathogen's genes are being regulated.
This study shows that gene regulation may be the result of the environments the strain inhabited before being identified.
Garbelotto uses a parallel example of a well-known human pathogen: particular strains of the H1N1 flu virus have been identified as highly virulent, so a diagnosis of one of these strains indicates to doctors that they should treat that flu aggressively.
"But, hypothetically, if you caught one of these aggressive strains of H1N1 from a guy that went to, for example, Paris, it could be 10 times more dangerous. You may never know from whom you got it, and it's even less likely that you'll be able to learn where your infector visited before passing the germ on to you."
In plants, Garbelotto said, tracking a pathogen
|Contact: Cheryl Dybas|
National Science Foundation