Paxillus adelphus Ve08.2h10 v2.0
Paxillus adelphus
Paxillus adelphus carpophores, by Hervé Gryta.

Within the framework of the JGI Mycorrhizal Genomics Initiative, we are sequencing a phylogenetically and ecologically diverse suite of mycorrhizal fungi (Basidiomycota and Ascomycota), which include the major clades of symbiotic species associating with trees and woody shrubs. Analyses of these genomes will provide insight into the diversity of mechanisms for the mycorrhizal symbiosis, including endo- and ectomycorrhiza.

General description: Paxillus adelphus is an ectomycorrhizal basidiomycete specifically associated to alders, first described by Orton in 1969. In France, it is found associated to Alnus glutinosa and Alnus incana, in wet-lands or along rivers. This species belongs to the Paxillaceae family, in which some members are hygrophilic and highly specialized on alders, such as Paxillus adelphus or Gyrodon lividus while some other members have a large ecological range and are generalist, such as Paxillus involutus.

Why sequence P. adelphus? P. involutus is one of the most studied ectomycorrhizal basidiomycota (more than 120 scientific publications since 1977, source: ISI Web of Knowledge) but nearly nothing is known about other members of the Paxillaceae family. Moreover, to understand host specificity, it seems really pertinent to compare 2 species (one specific, one generalist), belonging to the same genus. At this time, only few P. adelphus sequences (ITS, GPD, CytochromeC peroxidase, Cysteine peroxiredoxin type II) are available (GenBank, laboratory EDB) but the sequencing of P. involutus genome is in progress. The availability of genome sequence for both species and genome comparison will certainly allow 1) the identification of mechanisms related to the contrasted ecology of the two species, 2) to understand the role of ectomycorrhizal fungi in the biology of alders and 3) new insights in the comprehension of host specificity.

Genome Reference(s)