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Detecting the Pathogen That Stalks the Endangered Florida Torreya

Florida torreya (Torreya taxifolia) is a critically endangered conifer tree in swift decline since the 1950s. The torreya fungus (Fusarium torreyae) is currently devastating the remaining Florida torreya population. The fungus forms cankers, or localized dead areas, that damage branch or trunk tissue and eventually kill the trees.

The critically endangered Florida torreya tree has a limited range of only three counties in Florida and Georgia. Photo by Connie Barlow,, used with permission.

In the face of extinction from this pathogen, efforts are underway to collect and preserve the genetic diversity of Florida torreya at the Atlanta Botanical Garden with hopes of expanding these collections to other sites. But conservation efforts will only be successful if collected specimens are free of the torreya fungus.

USDA Forest Service scientist Tyler Dreaden and colleagues from the University of Florida are developing a genetic test to identify the torreya fungus. This work can ensure the health of the collections and reduce unknown risks to other species.

The researchers drew on published DNA sequences for F. torreyae canker pathogen and genetically related species. They mined these genetic codes to find the parts unique to the torreya pathogen.

The technique successfully distinguished the torreya fungus from other related fungal species. The next step — and ultimate goal — is to develop the method further so it can quickly detect the torreya fungus directly from Florida torreya tissue samples.

This study brings hope to expanding conservation efforts that preserve the genetic variation of Florida torreya in anticipation that it can thrive once again.

Read the article in the journal Forest Pathology. For more information, email Tyler Dreaden at