(a and d) Fluorescence microscopy showing Tulasnella helicospora hyphae stained with calcofluor white. (b and c) Light microscopy images of T. helicospora mycelium grown on agar. (d) orchid protocorms (of Orchis canariensis) germinated symbiotically with T. helicospora OP6.3d. [Photo credit: Jacopo Calevo.]

In the "1KFG: Deep Sequencing of Ecologically-relevant Dikarya" project (CSP1974), we are conducting genomic sequencing of key lineages of plant-interacting fungi and saprophytic fungi that are of significant ecological importance for comprehending terrestrial ecosystems. Furthermore, comparative genomic analysis of saprotrophic, mycorrhizal, and pathogenic fungi provides novel insights into specific and conserved adaptations associated with each fungal lifestyle.

Tulasnella helicospora OP6.3d

Orchids, especially at early stage of development, rely on symbiotic fungi like Tulasnella helicospora, that provide the plant with organic carbon, nitrogen, minerals, and water. T. helicospora is a common mycorrhizal partner of green orchids, particularly known for associating with the orchid genus Orchis, and belongs to the phylum Basidiomycota (order Cantharellales, family Tulasnellaceae). This fungus is widely distributed in Europe, normally found in different habitats, from grasslands to woodlands. T. helicospora can be easily cultivated in vitro. In particular, T. helicospora OP6.3d was isolated from mycorrhizal roots of the Mediterranean orchid Orchis patens subsp. brevicornis (Italy). This strain proved to be the most effective in promoting symbiotic seed germination and plantlet development in vitro of both Orchis patens and the sister species Orchis canariensis from Canary Islands. T. helicospora genome sequencing will allow us to better understand the functional association of this fungus with one of the most widespread European orchid genera.

Researchers who wish to publish analyses using data from unpublished CSP genomes are required to contact the PI and JGI to avoid potential conflicts in data use and coordinate other publications with the CSP master paper(s).