Fungalpedia – Note 133 Boletus
Boletus L.
Citation if using this entry: Bera et al. (in prep) Basidiomycota. Mycosphere
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig. 1
Basidiomycota, Agaricomycetes, Boletales, Boletaceae
One of the most highly valued wild edible mushrooms across the globe is Boletus s. str. with its exceptional commercial value playing a crucial economic role for local communities (Hall et al. 1998, Sabra & Walter 2001, Cui et al. 2016, Gelardi 2020). Colloquially known as porcini, king boletes, penny bun, or ceps, Boletus s. str. primarily displays an agaricoid habit, with occasional instances of sequestrate growth forms (Gelardi 2020). The typical feature of these porcini mushrooms is their ventricose to cylindrical stipe often with a broader base and raised reticulate ornamentation, and white mycelium occluding tube mouth in the initial developmental stage (Bashir et al. 2023). Morphologically, they are defined and differentiated from other boletoid genera based on the following cohesive key attributes: fleshy basidiomata with a white hymenophore turning into yellowish to olive-brown, context unchanging or rarely turning brownish or bluish on bruising or exposure, strong nutty odor, spore print usually olive-brown, basidiospores ellipsoid to rarely ovoid, pileipellis of diversified arrangements of hyphae, bilateral divergent hyphae of the hymenophoral trama, fertile caulohymenium, typical “boletoid-type” lateral stipe stratum, and inamyloid reaction of all hyphae with Melzer’s reagent (Smith & Thiers 1971, Singer 1986, Watling 2008, Cui et al. 2016, Gelardi 2020). However, the taxonomy and classification of the members of this genus is quite perplexing, as highlighted by Wang and Yao (2005).
Previously, Boletus s. str. was believed to be monophyletic when the molecular analysis was restricted to the type Boletus edulis Bull. and its allied species (Binder & Hibbett 2006, Dentinger 2007, Watling 2008, Desjardin et al. 2009, Dentinger et al. 2010, Wu et al. 2014, Cui et al. 2016, Gelardi et al. 2015, 2020). Later, various multi-gene phylogenetic analyses over the years on a global scale affirmed the higher diversity and polyphyly within this genus (Moor et al. 2002, Leonardi et al. 2005, Vizzini et al. 2007, Dentinger et al. 2010, Feng et al. 2012, Cui et al. 2016, Chakraborty et al. 2017, Crous et al. 2019) that was yet underexplored especially in temperate and tropical regions (Feng et al. 2012, Wu et al. 2014, Cui et al. 2016, Gelardi 2020). The recent classification based on molecular data divides Boletus s. str. into five distinct lineages: “porcini s. str.,” “Obtextiporus,” “Inferiboletus,” “Alloboletus,” and “Orientiboletus” (Dentinger et al. 2010, Feng et al. 2012, Cui et al. 2016, Gelardi 2020). Currently, a study on this ectomycorrhizal genus has been undertaken by Gelardi (2020) which encompassed the complete diversity, biogeographical distribution, and ecological relationship worldwide.
Type species: Boletus edulis Bull.
Figure 1. Boletus sinoedulis (HKAS 53613) a. Basidiomata. b. Basidiospores. c. Pleurocystidia. d. Basidia. e. Radical-vertical section of pileipellis. Scale bars: b-e = 10 μm. Drawn from Cui et al. 2016.
References
Bashir H, Sarwar S, Krisai-Greilhuber IRMGARD, Hanif A, Khalid AN 2023 – A new fungistic record of Boletus himalayensis– A morphologically complex porcini mushroom from Pakistan. Bangladesh Journal of Plant Taxonomy, 30(1), 99–106. https://eds.p.ebscohost.com/eds/detail/detail?vid=0&sid=a3e7f8d4-d506-462e-a36f-a60b058cafe0%40redis&bdata=JnNpdGU9ZWRzLWxpdmU%3d#AN=164700150&db=asn
Binder M, Hibbett DS 2006 – Molecular systematics and biological diversification of Boletales. Mycologia, 98(6), 971–981. https://www.tandfonline.com/doi/abs/10.1080/15572536.2006.11832626
Chakraborty D, Das K, Baghela A, Adhikari S, Halling RE 2017 – A new species of porcini mushroom from India with morphology and phylogeny. Nova Hedwig, 105(1–2), 197–204. https://www.cabdirect.org/cabdirect/abstract/20198659654
Crous PW, Carnegie AJ, Wingfield MJ, Sharma R, Mughini G, Noordeloos ME, … Silva BDB 2019 – Fungal Planet description sheets, 868–950. Persoonia: Molecular Phylogeny and Evolution of Fungi, 42, 291. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6712538/
Cui YY, Feng B, Wu G, Xu J, Yang ZL 2016 – Porcini mushrooms (Boletus sect. Boletus) from China. Fungal Diversity, 81, 189–212. https://link.springer.com/article/10.1007/s13225-015-0336-7
Cui YY, Feng B, Wu G, Xu J, Yang ZL 2016 – Porcini mushrooms (Boletus sect. Boletus) from China. Fungal Diversity, 81, 189–212. https://link.springer.com/article/10.1007/s13225-015-0336-7
Dentinger BT, Ammirati JF, Both EE, Desjardin DE, Halling RE, Henkel TW,… McLaughlin DJ 2010 – Molecular phylogenetics of porcini mushrooms (Boletus section Boletus). Molecular Phylogenetics and Evolution, 57(3), 1276–1292. https://www.sciencedirect.com/science/article/pii/S1055790310004100
Dentinger BTM 2007 – Systematics and evolution of porcini and clavarioid mushrooms. PhD thesis, University University of Minnesota.
Desjardin DE, Binder M, Roekring S, Flegel T 2009 – Spongiforma, a new genus of gastroid boletes from Thailand. Fungal Diversity, 37(1), 1–8. https://www2.clarku.edu/faculty/dhibbett/mbinder/pdf/Spongioforma.pdf
Feng B, Xu J, Wu G, Zeng NK, Li YC, Tolgor B,…Yang ZL 2012 – DNA sequence analyses reveal abundant diversity, endemism and evidence for Asian origin of the porcini mushrooms. PLoS One, 7(5), e37567. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0037567
Gelardi M 2020 – Diversity, biogeographic distribution, ecology, and ectomycorrhizal relationships of the edible Porcini Mushrooms (Boletus s. str., Boletaceae) worldwide: state of the art and an annotated checklist. Mushrooms, humans and nature in a changing world: Perspectives from ecological, agricultural and social sciences, 223–271. https://link.springer.com/chapter/10.1007/978-3-030-37378-8_8
Gelardi M, Vizzini A, Ercole E, Horak E, Ming Z, Li TH 2015 – Circumscription and taxonomic arrangement of Nigroboletus roseonigrescens gen. et sp. nov., a new member of Boletaceae from tropical South-Eastern China. PLoS One, 10(8), e0134295. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0134295
Hall IR, Buchanan PK, Yun W, Cole ALJ 1998 – Edible and poisonous mushrooms: an introduction. New Zealand Institute for Crop and Food Research Limited, Christchurch. https://natlib.govt.nz/records/21101721?search%5Bpath%5D=items&search%5Btext%5D=Hall%2C+Ian+R.
Leonardi M, Paolocci 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(2), 411–416. https://academic.oup.com/femsle/article/243/2/411/496383
Moor D, Brodmann P, Nicholas G, Eugster A 2002 – Polymerase chain reaction (PCR) for the detection of king bolete (Boletus edulis) and slippery jack (Suillus luteus) in food samples. European Food Research and Technology, 214, 340–345. https://link.springer.com/article/10.1007/s00217-001-0458-x
Sabra A, Walter S 2001 – Non-wood forest products in the Near East: a regional and national overview. Working paper FOPW/01/2. FAO, Rome. https://www.fao.org/3/y1797e/y1797e.pdf
Singer R 1986 – The Agaricales in modern taxonomy, 4th edn. Koeltz Scientific Books, Koenigstein. https://www.worldcat.org/title/15034197
Smith AH, Thiers HD 1971 – The boletes of Michigan. University of Michigan Press, Ann Arbor. https://quod.lib.umich.edu/f/fung1tc/AGK0838.0001.001?rgn=main;view=fulltext
Vizzini A, Mello A, Ghignone S, Sechi C, Ruiu P, Bonfante P 2007 – Boletus edulis complex: from phylogenetic relationships to specific primers. Pagine di Micologia, 30, 48–52. https://iris.unito.it/handle/2318/59352
Wang QB, Yao YJ 2005 – Boletus reticuloceps, a new combination for Aureoboletus reticuloceps. Sydowia, 57(1), 131–136. http://www.sydowia.at/syd57-1/art9-Wang.htm
Watling R 2008 – A manual and source book on the boletes and their allies (Vol. 24). Oslo: Fungiflora. https://www.mykoweb.com/systematics/literature/A%20Manual%20and%20Source%20Book%20on%20the%20Boletes%20and%20Their%20Allies.pdf
Wu G, Feng B, Xu J, Zhu XT, Li YC, Zeng NK, …Yang ZL 2014 – Molecular phylogenetic analyses redefine seven major clades and reveal 22 new generic clades in the fungal family Boletaceae. Fungal Diversity, 69, 93–115. https://link.springer.com/article/10.1007/s13225-014-0283-8
Entry by
Ishika Bera, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand
(Edited by Kevin D Hyde)