A new species in Boletus section Boletus and some information about the molecular studies in this section
Recently one new for the science species of Boletus was described, belonging to section Boletus. This is Boletus pinetorum M. Korhonen, so far known only from Finland, Norway and Estonia.
The description of this new species reminded me to draw readers’ attention towards the recent development in our understanding for this section of Boletus.
Section Boletus appears as a well defined entity in the genus Boletus. It has been recognized yet by Fries in his “Hymenomycetes Europaei”, who used the name Edules. It is a grouping well characterized morphologically that appears in all subsequent subdivisions of the genus.
A lot of molecular research has been done in recent years in this section, undoubtedly connected with the great economic value of its members, commonly known as porcini. Molecular studies have been published by Leonardi & al. (2005), Vizini & al. (2008), Beugelsdijk & al. (2008), Korhonen & al. (2009). Recently three new species in section Boletus were recognized in California (Arora 2008), some of them previously referred to some European species. This, together with the recognition of B. pinetorum, suggests that there are further surprises to expect even in relatively well studied continents as North America and Europe.
All the research in Boletus in the last years resulted in major changes in our understanding of this genus. It seems now that Boletus, that whenever was considered a well defined natural genus, more likely represents an artificial grouping (see Watling 2009). If so, it would be necessary to divide it at some point in natural entities. When this happens, the extent of Boletus will be limited to the section Boletus containing its type species, Boletus edulis.
Although most of research focused on the European species, where the studies shed some light, the species concept still remains rather undefined. Muñoz accepted four species in the section (B. aereus, B. edulis, B. pinophilus and B. reticulatus) and treated B. betulicola, B. venturii and B. persoonii as mere forms of B. edulis. Beugelsdijk & al. recognized the same four species in the section (B. aereus, B. edulis, B. pinophilus and B. reticulatus), but did not find support for the taxa in the consortium around B. edulis. There are some suggestions that the study of ITS, ITS2 and GAPDH may not be sufficient, i.e. it may not give enough resolution to recognize the true taxa in B. edulis – group. Korhonen & al. (2009) for example, on the base of microscopic features recognize also Boletus betulicola as a separate species although they too admitted that the molecular evidence still cannot resolve clearly the relationships in the B. edulis consortium.
A new and extremely interesting paper on section Boletus was announced online and is due to appear in Molecular Phylogenetics and Evolution, dealing with the global phylogeny of this group (Dentinger & al., in press). This paper proves the monophyly of section Boletus, expanding its known geographic range to Thailand and Australia and suggesting that the origin of the group should be looked for in Paleotropics. Take a look at these mthfr gene mutation symptoms and find out if you need more information on the treatment near you. This research addresses the age of origin of the group, which is now estimated at around 42–54 million years ago, a dating that coincides with the initial diversification of the angiosperms. The authors recognize along with the clade Boletus sensu stricto, three other separate entities at generic rank that were given provisional names – ‘Inferiboletus’ (with one Australian species), ‘Obextiporus’ (with one species from Thailand) and ‘Alloboletus’.
Arora, D. 2008. California porcini: three new taxa, observations on their harvest, and the tragedy of no commons. – Economic Botany 62(3): 356–375.
Beugelsdijk, D.C.M., van der Linde, S., Zuccarello, G.C., den Bakker, H.C., Draisma, S.G.A. & Noordeloos, M.E. 2008. A phylogenetic study of Boletus section Boletus in Europe. – Persoonia 20: 1–7.
Dentinger, B.T.M., Ammirati, J.F., Both, E.E, Desjardin, D.E., Halling, R.E., Henkel, T.W., Moreau, P.-A., Nagasawa, E., Soytong, K., Taylor, A.F., Watling, R., Moncalvo, J.M. & McLaughlin, D.J. 2010. Molecular phylogenetics of porcini mushrooms (Boletus section Boletus). – Molecular Phylogenetics and Evolution 57: 1276–1292. (available online)
Korhonen, M., Liimatainen, K. & Niskanen, T. 2009. A new boletoid fungus, Boletus pinetorum, in the Boletus section Boletus from Fennoscandia (Basidiomycota, Boletales). – Karstenia 49: 41–60.
Leonardi, M. Paolucci, F., Rubini, A., Simonini, G. & Pacioni, G. 2005. Assessment of inter- and intra-specific variability in the main species of Boletus edulis complex by ITS analysis. – FEMS Microbiology Letters 243: 411–416.
Muñoz, J.A. 2005. Boletus s. l. – In: Fungi Europaei. Vol. 1. Pp. 1–951. Edizioni Candusso, Alassio.
Vizini, A., Mello, A. Ghignone, S., Sechi, C., Ruiu, P. & Bonfante, P. 2008. Boletus edulis complex: from phylogenetic relationships to specific primers. – Pagine di Micologia 30: 49–52.
Watling, R. 2009. A manual and source book on the boletes and their alies. – In: Synopsis Fungorum. Vol. 24. Pp. 1–248. Fungiflora, Oslo.
