Chalara hyalina [Image by Lilla Virag]

In the “1KFG: Deep Sequencing of Ecologically-relevant Dikarya” project (CSP1974), we are sequencing 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.

Chalara hyalina CBS 558.92

This species belongs to the Laboulbeniomycetes, a small and poorly known class in the Ascomycota. It comprises cca. 2000 species currently in two orders, the species-poor Pyxidiophorales and the diverse Laboulbeniales. Pyxidiophorales are associated with arthropods for dispersal while all described species of Laboulbeniales are unculturable, obligate biotrophic ectoparasites of insects or other arthropods. Laboulbeniales produce small (~0.1 to 3 mm tall) thalli on the exoskeleton of insects. They represent secondarily reduced, mostly non-hyphal fungi with complex thallus morphologies. Thalli often consist of a fixed number of well-defined cells and true hyphal growth is only observed in some genera in the form of hyphae or haustoria penetrating the host (Haelewaters et al. 2017).

The genus Chalara is polyphyletic. Several species are plant pathogens and are related to Ceratocystis (Microascales, Sordariomycetes) or belong to the Helotiales (Cai et al 2009). Chalara hyalina was reported to have a distinct phylogenetic position in the Pyxidiophorales, within the poorly known class Laboulbeniomycetes. The species was described from cysts of the nematode Heterodera (Morgan-Jones et al 1984).

The genome sequence of this species is the first from the order Pyxidiophorales and will help understand the phylogenetic position of this order in the fungal tree of life, as well as the evolution of this group of fungi.

Researchers who wish to publish analyses using data from unpublished CSP genomes are respectfully required to contact the PI and JGI to avoid potential conflicts on data use and coordinate other publications with the CSP master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