Armillaria novae-zelandieae [Photo source: The Hidden Forest, used with expressed written permission from Clive Shirley]

In the “1KFG: Deep Sequencing of Ecologically-relevant Dikarya” project (CSP1974), we aim to sequence additional sampling of genomic diversity within keystone lineages of plant-interacting fungi and saprophytic fungi that are of special ecological importance for understanding terrestrial ecosystems. In addition, comparative genome analysis with saprotrophic, mycorrhizal and pathogenic fungi will provide new insights into the specific and conserved adaptations associated with each fungal lifestyle.

Armillaria novae-zelandiae 2840

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 leads to significant losses in forest areas or woody plants, including forests, parks or vineyards, among others, mostly in the temperate zone. The infection is usually characterized by 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 in 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 novae-zelandiae (G.Stev.)¹ was identified as a plant pathogen in New Zealand. It is also distributed across Eastern Australia and New Guinea and is a highly invasive plant pathogen causing root rot preferentially in conifers but also in broadleaved trees. It grows as dense clusters in areas with less sunlight and damp soil. A mature cap is brownish yellow in color and is marked by a slimy appearance when fresh. The mature fruiting body is about 15cm in length, with cap margins striated towards the centre followed by stipes with bulbous ends. The diploid strain Armillaria novae-zelandiae 2840 was received from Jonathan Plett.

Researchers who wish to publish analyses using data from unpublished CSP genomes are respectfully required to contact the PI and JGI to avoid potential conflicts on data use and coordinate other publications with the CSP master paper(s).