Home • Atractiellales rhizophila v2.0
Photo of Atractiellales rhizophila v2.0
Mycelium of Atractiellales growing on malt extract agar in a petri dish (top). Dikaryotic nuclei are evident when stained with DAPI (bottom). Photo credits Gregory Bonito & Khalid Hameed.

Within the framework of the CSP 'Metatranscriptomics of Forest Soil Ecosystems' project, we are aiming to explore the interaction of forest trees with communities of soil fungi, including ectomycorrhizal symbionts that dramatically affect bioenergy-relevant plant growth, and saprotrophic soil fungi impacting carbon sequestration in forests. We are sequencing the metatranscriptome of soil fungi (i.e., wood decayers, litter and humus saprotrophs, and ectomycorrhizal symbionts) in woody debris, litter/humus, rhizosphere and ectomycorrhizal roots of ecosystems representative of major Earth ecosystems, the boreal, temperate and mediterranean forests. We are also sequencing the genome of the most abundant fungal species harvested on studied sites to serve as the foundation for a reference database for metagenomics of fungi and for a comprehensive survey of the potential soil fungal metabolome.

The Atractiellales are a newly discovered and poorly studied group of filamentous fungi belonging to a phylogenetically distinct clade within the rust lineage (Pucciniomycotina). They are characterized by several ultrastructural features, including symplechosomes and a simple septal pore structure surrounded by structures known as atractosomes [1]. Some species make tiny fruiting bodies while others appear to be asexual. Some species of Atractiellales are associated with beetles and their galleries. Others are associated with living plants and decaying plant debris.  The isolate whose genome was sequenced here was isolated from healthy roots of Populus deltoides. Its mycelium is dikaryotic without clamp connections; no fruiting has been observed despite multiple attempts to stimulate fructification.  Culture-independent sequencing studies confirm that this species is often abundant in the root endosphere of Populus deltoides [2] in natural ecosystems. Our isolate (PMI 95) can grow intracellularly as a root endophyte on a wide diversity of plants including trees (e.g. Populus, Pinus, Quercus) and grasses (Zea mays). This isolate was recently renamed as Atraciella rhizophila (Bonito et al., 2017)


References
Oberwinkler, F. et al. Two new pycnidial members of the Atractiellales: Basidiopycnis hyalina and Proceropycnis pinicola. Mycologia 98, 637-649, doi:Doi 10.3852/Mycologia.98.4.637 (2006).

Gottel, N. R. et al. Distinct Microbial Communities within the Endosphere and Rhizosphere of Populus deltoides Roots across Contrasting Soil Types. Applied and Environmental Microbiology 77, 5934-5944 (2011).

Bonito, G. et al. Atractiella rhizophila, sp. nov., an endorrhizal fungus isolated from the Populus root microbiome. Mycologia 109:1, 18-26, doi:10.1080/00275514.2016.1271689 (2017)