Ganoderma is a genus of polypore fungi in the family Ganodermataceae that includes about 80 species, many from tropical regions. Because of their genetic diversity, use in traditional Asian medicines, and potential in bioremediation, they are an important genus economically. Ganoderma can be differentiated from other polypores because they have a double-walled basidiospore. They are sometimes called shelf mushrooms or bracket fungi.
The genus Ganoderma was established as a genus in 1881 by Karsten and included only one species, G. lucidum (Curtis) Karst. Previously, this taxon was characterized as Boletus lucidus Curtis (1781) and then Polyporus lucidus (Curtis) Fr. (1821) (Karsten 1881). The species P. lucidus was characterized by having a laccate (shiny or polished) pileus and stipe, and this is a character that Murrill suspected was the reason for Karsten’s division because only one species was included, G. lucidum . Patouillard revised Karsten’s genus Ganoderma to include all species with pigmented spores, adhering tubes and laccate crusted pilei, which resulted with a total of 48 species classified under the genus Ganoderma in his 1889 monograph. Until Murrill investigated Ganoderma in North America in 1902, previous work had focused solely on European species including, for example, G. lucidum, G. resinaceum Boud. (1890) and G. valesiacum Boud. (1895).
Ganoderma are characterized by basidiocarps that are large, perennial, woody brackets also called "conks". They are lignicolous and leathery either with or without a stem. The fruit bodies typically grow in a fan-like or hoof-like form on the trunks of living or dead trees. They have double-walled, truncate spores with yellow to brown ornamented inner layers.
The genus was named by Karsten in 1881. Members of the family Ganodermataceae were traditionally considered difficult to classify because of the lack of reliable morphological characteristics, the overabundance of synonyms, and the widespread misuse of names. Until recently, the genus was divided into two sections – Ganoderma, with a shiny cap surface (like Ganoderma lucidum), and Elfvingia, with a dull cap surface (like Ganoderma applanatum).
Phylogenetic analysis using DNA sequence information have helped to clarify our understanding of the relationships amongst Ganoderma species. The genus may now be divided into six monophyletic groups:
- G. colossus group
- G. applanatum group
- G. tsugae group
- Asian G. lucidum group
- G. meredithiae group
- G. resinaceum group
With the rise of molecular phylogenies in the late 20th century, species concept hypotheses were tested to determine the relatedness amongst the nuanced morphological variabilities of the laccate Ganoderma taxa. In 1995, Moncalvo et al constructed a phylogeny of the rDNA, which was the universally accepted locus at that time, and found five major clades of the laccate species amongst the 29 isolates tested. It turned out that G. lucidum was not a monophyletic species, and further work needed to be done to clarify this taxonomic problem. They also found that G. resinaceum from Europe, and the North American 'G. lucidum', which Adaskaveg and Gilbertson found to be biologically compatible in vitro, did not cluster together. Moncalvo et al. reject biological species complexes as a sole tool to distinguish a taxon, and suggested using a combination between biological and phylogenetic species concepts to define unique Ganoderma taxa.
In 1905, American mycologist William Murrill delineated the genus Tomophagus to accommodate the single species G. colossus (then known as Polyporus colossus) which had distinctive morphological features that did not fit in with the other species. Historically, however, Tomophagus has generally been regarded as a synonym for Ganoderma. Nearly a century later, phylogenetic analyses vindicated Murrill's original placement, as it has shown to be a taxonomically distinct appropriate genus.
Some Ganoderma species can cause major long-term crop losses, especially with trees:
- G. orbiforme (= G. boninense), G. zonatum and G. miniatocinctum are responsible for basal stem rot disease in Asian oil palm plantations.
- G. philippii and G. pseudoferreum are responsible for the root rot of cacao, coffee, rubber and tea trees.
Ganoderma are wood-decaying fungi with a cosmopolitan distribution. They can grow on both coniferous and hardwood species. They are white-rot fungi with enzymes that allow them to break down wood components, such as lignin and cellulose. There has been significant research interest on the wood-degrading enzymes of Ganoderma species for industrial applications, such as biopulping and bioremediation.
For centuries, Ganoderma species have been used in traditional medicine in many parts of Asia. These species are often mislabeled as 'G. lucidum', although genetic testing has shown this to be multiple species such as G. lingzhi, G. multipileum, and G. sichuanense. Several species of Ganoderma contain diverse phytochemicals with undefined properties in vivo, such as triterpenoids and polysaccharides, an area of investigation under basic research.
Although various Ganoderma species are used in folk medicine for supposed benefits and have been investigated for their potential effects in humans, there is no evidence from high-quality clinical research that Ganoderma phytochemicals have any effect in humans, such as in cancer research.
- Ganoderma applanatum - Also known as the artist's conk. An infestation of this species was the main factor in the loss of the Anne Frank Tree.
- Ganoderma lingzhi - Also known as reishi, a mushroom used extensively in traditional Asian medicine.
- Ganoderma lucidum - A polypore with limited distribution in Europe and parts of China, often misidentified on products labeled reishi or lingzhi that actually contain G. lingzhi, because of the persistence of outdated naming conventions.
- Ganoderma multipileum
- Ganoderma tsugae - A polypore which grows on conifers, especially hemlock, giving it its common name, hemlock varnish shelf. Similar in appearance to Ganoderma lucidum and a close relative, which typically grows on hardwoods.
- Kirk PM, Cannon PF, Minter DW, Stalpers JA (2008). Dictionary of the Fungi (10th ed.). Wallingford: CABI. p. 272. ISBN 978-0-85199-826-8.
- Liddell, Henry George & Robert Scott (1980). A Greek-English Lexicon (Abridged Edition). United Kingdom: Oxford University Press. ISBN 0-19-910207-4.
- Karsten, P. 1881. Enumeratio Boletinarum et Polyporarum Fennicarum systemate novo dispositorum. Rev. Mycol. 3:16-18
- Murrill, W. A. 1902. The Polyporaceae of North America, genus I Ganoderma. Bull. Torrey Bot. Club 29:599-608.
- Patouillard, N. 1889. Le genre Ganoderma. Bull. Soc. mycol. Fr. 5:64-80.
- Atkinson, G. F. 1908. Observations on Polyporus lucidus Leys and some of its Allies from Europe and North America. Botanical Gazette 46:321-338.
- Adaskaveg, J. E. 1986. Studies of Ganoderma lucidum and Ganoderma tsugae (Delignification, Mating Systems, Root Rot, Cultural Morphology, Taxonomy). Dissertation. The University of Arizona.
- Murrill, W. A. 1908. Agaricales (Polyporaceae). North Amer. Flora 9:73-131.
- Karsten PA. (1881). "Enumeratio Boletinearum et Polyporearum Fennicarum, systemate novo dispositarum". Revue mycologique, Toulouse (in Latin). 3 (9): 16–19.
- Smith BJ, Sivasithamparam K (2003). "Morphological studies of Ganoderma (Ganodermataceae) from the Australasian and Pacific regions". Australian Systematic Botany. 16 (4): 487–503. doi:10.1071/SB02001.
- Ryvarden L. (1985). "Type studies in the Polyporaceae 17: species described by W. A. Murrill". Mycotaxon. 23: 169–198.
- Hibbett DS, Donoghue MJ. (1995). Progress toward a phylogenetic classification of the Polyporaceae through parsimony analysis of mitochondrial ribosomal DNA sequences. Can J Bot 73(S1):S853–S861.
- Hibbett DS, Thorn RG. (2001). Basidiomycota: Homobasidiomycetes. The Mycota VII Part B. In: McLaughlin DJ, McLaughlin EG, Lemke PA, eds. Systematics and evolution. Berlin-Heidelberg, Germany: Springer-Verlag. p 121–168.
- Hong SG, Jung HS (2004). "Phylogenetic analysis of Ganoderma based on nearly complete mitochondrial small-subunit ribosomal DNA sequences". Mycologia. 96 (4): 742–55. CiteSeerX 10.1.1.552.9501. doi:10.2307/3762108. JSTOR 3762108. PMID 21148895.
- Moncalvo, J.-M., Wang, H.-F., and Hseu, R.-S. 1995. Gene phylogeny of the Ganoderma lucidum complex based on ribosomal DNA sequences. Comparison with traditional taxonomic characters. Mycological Research 99:1489-1499.
- Adaskaveg, J. E., and Gilbertson, R. L. 1986. Cultural studies and genetics of sexuality of Ganoderma lucidum and G. tsugae in relation to the taxonomy of the G. lucidum complex. Mycologia:694-705.
- Murrill WA. (1905). "Tomophagus for Dendrophagus". Torreya. 5: 197.
- Furtado JS. (1965). "Ganoderma colossum and the status of Tomophagus". Mycologia. 57 (6): 979–84. doi:10.2307/3756901. JSTOR 3756901.
- Ling-Chie Wong, Choon-Fah J. Bong, A.S. Idris (2012) Ganoderma Species Associated with Basal Stem Rot Disease of Oil Palm. American Journal of Applied Sciences 9(6): 879-885 (ISSN 1546-9239)
- Loyd, A. L; Held, B. W; Linder, E. R; Smith, J. A; Blanchette, R. A (2018). "Elucidating wood decomposition by four species of Ganoderma from the United States". Fungal Biology. 122 (4): 254–263. doi:10.1016/j.funbio.2018.01.006. PMID 29551199.
- "FBRI: New Enzymes for Biopulping". Archived from the original on 2009-01-04. Retrieved 2008-11-15.
- Matos AJ, Bezerra RM, Dias AA (September 2007). "Screening of fungal isolates and properties of Ganoderma applanatum intended for olive mill wastewater decolourization and dephenolization". Lett. Appl. Microbiol. 45 (3): 270–5. doi:10.1111/j.1472-765X.2007.02181.x. PMID 17718838.
- Wachtel-Galor, Sissi (2011). "Chapter 9 Ganoderma lucidum (Lingzhi or Reishi)A Medicinal Mushroom". Herbal Medicine: Biomolecular and Clinical Aspects. 2nd edition. CRC Press Taylor and Francis. ISBN 978-1-4398-0713-2. Retrieved 2017-02-22.
- Hennicke, F., Z. Cheikh-Ali, T. Liebisch, J.G. Maciá-Vicente, H.B. Bode, and M. Piepenbring. 2016. “Distinguishing commercially grown Ganoderma lucidum from Ganoderma lingzhi from Europe and East Asia on the basis of morphology, molecular phylogeny, and triterpenic acid profiles.” Phytochemistry 127:29–37.
- Hapuarachchi, K., T. Wen, C. Deng, J. Kang, and K. Hyde. 2015. “Mycosphere Essays 1: Taxonomic Confusion in the Ganoderma lucidum Species Complex.” Mycosphere 6:542–559.
- Jin, X; Ruiz Beguerie, J; Sze, D. M; Chan, G. C (2016). "Ganoderma lucidum (Reishi mushroom) for cancer treatment". Cochrane Database of Systematic Reviews. 4: CD007731. doi:10.1002/14651858.CD007731.pub3. PMC 6353236. PMID 27045603.
- "Horse chestnut tree diseased" (Press release). The Anne Frank House. Archived from the original on 3 October 2006. Retrieved 2006-11-17.
- Kuo M., MushroomExpert.Com, Ganoderma tsugae. (2004, February). Retrieved June 15, 2007.