The fungus was observed on a deciduous tree, on April 14th 2008, in the forest​ of Chizé (Deux-Sèvres, France). P. spadiceum is visible every year at different times of the year. Note for example that we have also observed it on honey locust (Gleditsia triacanthos), in 2009 in a park in Saintes (Charente-Maritime, France). [Image credit: Patrice Tanchaud]

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.

Porostereum spadiceum

The genus Porostereum is a group of fungi from the order Polyporales. This genus is composed of crust fungi belonging to the family Phanerochaetaceae. Porostereum spadiceum is known from Europe, Armenia, and Morocco (Boidin and Gilles 2002, Talbot 1954, Welden 1975). P. spadiceum (Synonym : Lopharia spadicea) was described in 1990 (Hjortstam, K.; Ryvarden, L.,1990).) The fungus is generally found on branches and trunks with or without hardwoods, or on piles of dead wood, especially Fagus. The common period to find P. spadiceum is from spring to autumn.

Studies on P. spadiceum and potential applications of P. spadiceum

P. spadiceum was subject to several potential application studies, such as for agriculture, wastewater treatment, and metabolite production. The potential use of P. spadiceum for sustainable agriculture was tested by Hamayum et al 2017, and shown that the presence of P. spadiceum could promote salt tolerance of soybean plants. The mechanism of salt tolerance involved gibberellin production by the fungi. In another study, P. spadiceum was shown to produce volatile compounds that were released from mycelia. Their inhibitory activity against plant-pathogenic bacteria and fungi were investigated (Hamamoto et al 2021). Volatile compounds from a culture of P. spadiceum inhibited the colony formation of plant-pathogenic bacteria, including Clavibacter michiganensis subsp. michiganensis and Ralstonia solanacearum, while also inhibiting the conidial germination of plant-pathogenic fungi including Alternaria brassicicola and Colletotrichum orbiculare. The major compound was isolated from the culture filtrate of P. spadiceum, and identified as 3,4-dichloro-4-methoxybenzaldehyde (DCMB).

In a bioremediation context, Anastasi et al 2012 demonstrated that P. spadiceum was able to decolorize textile industry effluents and reduce their chemical oxygen demand (COD). Interestingly the decolorization was related to the production of oxidative enzymes (e.g. Manganese peroxidase, Laccase). Along the same lines, P. spaieceum was tested for the biodegradation of landfill leachate (a highly polluted effluent). Results have shown the capacity of this fungus to decolorize this effluent with a high peroxidase activity (Spina et al 2018)

Isolation of the strain Porostereum spadiceum BS34

P. spadiceum strain BS34 was isolated in 2014 near Bousalem (Tunisia) by Professor Tahar Mechichi. The fungus was isolated from an Australian pine tree (Casuarina equisetifolia).

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).