Fighting back against ash dieback: Researchers sequence resistant tree

Ash dieback symptoms. Courtesy of WTPL/Mike Ryder.

Ash dieback symptoms. Courtesy of WTPL/Mike Ryder.

Scientists are fighting back against a deadly ash tree fungus on the genetic level.

The first genetic information from a tree known as tree 35 that survived an outbreak of the deadly fungus that causes ash dieback in Denmark has been sequenced by researchers in the United Kingdom (U.K), which provides new insight into how certain trees resist the fungal attack. They also are working to sequence the genome the fungus that causes ash dieback (Chalara fraxinea), according to the BBC.

Tree 35 is an ash tree that survived a dieback epidemic that killed 60 to 90 percent of the ash population in Denmark. By mapping tree 35’s genome, researchers hope they’ll be able to find what causes resistance to the fungus at the genetic level. This information could provide tree breeders with recommendations on the proper breeding combinations to enhance resistance, according to a statement from The Sainsbury Laboratory, which is leading the study with The John Innes Centre.

“We have managed to generate the first sequence data just two months after receiving samples,” said Dr. Mario Caccamo, acting director of The Genome Analysis Centre, which sequenced the genome. “Speed is important to the research so that all those studying the epidemic can start to look for clues to tackle it.”

Tree 35 is a mostly female tree and researchers hope its genome will help identify a primarily male tree that also is resistant to dieback and breed them. Ash trees do not self-pollinate, meaning they must have pollen from another ash tree to reproduce.

Ash dieback is marked by crown death and leaf loss and eventually, tree death. Last fall, dieback was detected in Suffolk and Ashwellthorpe, which led to an immediate ban on the import of ash trees into the country. Earlier this year, the U.K. further tightened tree import rules to help track certain trees imported from the European Union, including ash.

The genomes are available, free of charge, on the crowdsourcing site OpenAshDieback. In March, researchers released the first genomic data for the fungus for others to download and analyze. It’s a novel approach but one researchers believe is necessary to stem the damage posed by dieback.

“This is not how science normally works, but finding solutions is the priority,” said Professor Sophien Kamoun, head of The Sainsbury Laboratory, in a statement.

Dieback has decimated ash trees around Europe. In the U.K., infected trees have been found at 500 sites across the country, with most in East Anglia and the Southeast.

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