This genome was sequenced as a part of the large-scale multi-genome JGI CSP Saprotrophic Agaricomycotina Project (SAP), which focuses on the diversity and evolution of decay mechanisms, organismal phylogenetic relationships, and developmental evolution. A large collaborative effort led by PI of this project, David Hibbett (Clark University) aims for master publication(s) of the SAP data analysis. Researchers who wish to publish analyses using data from unpublished SAP genomes are respectfully required to contact the PI and JGI to avoid potential conflicts on data use and coordinate other publications with the SAP master paper(s).
The genus Hydnomerulius (Boletales, Basidiomycota) contains a single species, H. pinastri, which produces a brown-rot similar to that of Serpula and Coniophora species. Hydnomerulius pinastri is sometimes called the spiny dry rot fungus for obvious reasons. As the resupinate (crust-like) fruiting body develops, the spore-bearing layer first becomes wrinkled and then produces tooth or spine like structures, followed by increased hyphal pigmentation. Serpula, Coniophora, and Hydnomerulius represent morphologically and ecologically similar lineages in the Boletales, but they are not closely related. Hydnomerulius pinastri is the sister group to the Boletineae, which harbors some 800 predominantly ectomycorrhizal species including highly valued edibles, such as porcini mushrooms. The ecological requirements of H. pinastri are identical to those of the dry rot fungus Serpula lacrymans. The wood of conifers is the substrate of choice and both species attack wooden building structures. However, H. pinastri infestations occur rarely and if they do, they are much less aggressive compared to the fatal damage left by S. lacrymans. The brown-rot nutritional mode in the Boletales has received much attention lately, with the emergence of completed genome projects in this fungal group. Class II peroxidases, the enzymes responsible for rapid delignification of wood in white rot fungi, are absent in S. lacrymans and Coniophora puteana. These fungi access cellulose and hemicellulose after modifying the lignin compounds of wood to the extent that the converted lignin becomes recalcitrant to further decay by other saprotrophs. Thus, the ecology of brown-rot fungi creates important carbon sinks in forests, delaying the immediate return of carbon to the carbon cycle. This project will also present an opportunity to study morphological and nutritional transitions in the Boletales as a model system. It has been hypothesized that ectomycorrhizal mushrooms evolved repeatedly and independently from resupinate brown-rot forms in the Boletales, and these shifts may have been promoted by the loss of highly reactive oxidative wood decaying enzymes. A direct comparison of the genome of H. pinastri and the genome of ectomycorrhizal Boletales, such as Paxillus involutus, which is closely related to H. pinastri, will be instrumental to evaluate these hypotheses.
Genome Reference(s)
Kohler A, Kuo A, Nagy LG, Morin E, Barry KW, Buscot F, Canbäck B, Choi C, Cichocki N, Clum A, Colpaert J, Copeland A, Costa MD, Doré J, Floudas D, Gay G, Girlanda M, Henrissat B, Herrmann S, Hess J, Högberg N, Johansson T, Khouja HR, LaButti K, Lahrmann U, Levasseur A, Lindquist EA, Lipzen A, Marmeisse R, Martino E, Murat C, Ngan CY, Nehls U, Plett JM, Pringle A, Ohm RA, Perotto S, Peter M, Riley R, Rineau F, Ruytinx J, Salamov A, Shah F, Sun H, Tarkka M, Tritt A, Veneault-Fourrey C, Zuccaro A, Tunlid A, Grigoriev IV, Hibbett DS, Martin F
Convergent losses of decay mechanisms and rapid turnover of symbiosis genes in mycorrhizal mutualists.
Nat Genet. 2015 Apr;47(4):410-5. doi: 10.1038/ng.3223