Armillaria tabescens (Scop.) Emel, photographed in Wayne National Forest, Athens Co., Ohio, USA [Photo source: Dan Molter, used under the Creative Commons Attribution-Share Alike license via Mushroom Observer]

This genome was sequenced as part of the JGI CSP "1000 Fungal Genomes – Deep Sequencing of Ecologically-relevant Dikarya" project. Within the framework of this project, we are sequencing keystone lineages of saprophytic, mycorrhizal, and endophytic fungi that are of special ecological importance. Dozens of sequenced species were harvested from Long Term Observatories to serve as the foundation for a reference database for metagenomics of fungi and for a comprehensive survey of the soil fungal metatranscriptome.

Armillaria tabescens CCBAS 213

Members of the genus Armillaria belong to the Physalacriaceae, a highly diverse family in the Agaricales containing white rot wood decayers and devastating tree pathogens. They cause shoestring root rot, which lead to significant losses in forests, parks or vineyards, among others, mostly in the temperate zone. The infection is usually characterized by the presence of rhizomorphs and mycelial mats between the bark and cambium layer of the host root. Rhizomorphs are shoestring-like multicellular structures, which are analogous to plant roots in appearance and forage for food by spreading inside the soil. Armillaria spp. produce macroscopic fruiting bodies that are edible and known as honey mushrooms. Many existing individuals of Armillaria are believed to be the largest and oldest terrestrial organisms known on earth.

We aim to sequence the genomes of several Armillaria strains representing both aggressive pathogens and white-rot saprotrophs. This will allow us to gain insights into the evolution of pathogenicity and the mechanisms of interaction between Armillaria and their host trees. It will further help understanding the biology of these species, including their strategies for host invasion, for wood decay, and the development of rhizomorphs and fruiting bodies. We hope these resources will open the door for developing efficient management strategies for limiting the spread and damage to forest ecosystems.

Armillaria tabescens (Scop.), commonly known as the Ringless Honey Mushroom, belongs to the Desarmillaria subgenus which are characterized by stipes without a ring¹. A. tabescens is commonly found both in North America and Europe and favors the more southerly regions of both continents. They can act both as a saprobe and/or parasites of hardwood trees, it is pathogenic towards Eucalyptus and Quercus^1,2 species and can affect other hardwood trees as well. Usually found in growing clusters of many mushrooms from one central mass of mycelium found just below the ground at the base of the trees or near dead stumps.

The 1KFG project is a large collaborative effort aiming for master publication(s). Please do contact the PI for 1KFG - Deep Sequencing of Ecologically-relevant Dikarya (Dr. Francis Martin) for permission prior to the use of any data in publications.