New Clues Discovered on Divergent Origin of Sudden Oak Death Pathogen

Discovering the source of pathogens and its movement from one location is an important information for quarantine regulators. This is specially applied to Phyopthota ramorum fungus, the causal pathogen of the sudden oak death. The relatedness of the three distinct clonal lineages, or genetic descendants of P. ramorum--EU1, NA1 and NA2--was not initially known.

The team led by Nik Grunwald of the U.S. Department of Agriculture-Agricultural Research Service and the North Carolina State University conducted  an extensive DNA sequence analysis and found out that the three lineages are between 1.5 milliion and 5.4 million years old. Furthermore, the European lineage maybe older than the American lineage and that the three lineages originated from three different geographic locations rather than one location, prior to introduction to Europe and North America. This has huge bearing on the need for greater caution when approving plant material for introduction into the U.S. that could introduce additional strains of the pathogen, according to the researchers.

See the press release for more details at: http://www.ars.usda.gov/is/pr/2009/090327.htm