GANODERMA: CHARACTERISTICS, HABITAT, USES AND SPECIES - BIOLOGY - 2025

Ganoderma is a genus of cosmopolitan basidiomycetes fungi that belongs to the Ganodermataceae family. This group of fungi causes rotting of various woody plants, by decomposing lignin and cellulose.

Morphologically, the basiodiocarps of the fungi of the genus Gonoderma are characterized by being sessile, stipitate, and imbricate (although some are not). The color of the surface of the umbrella and the hymenophore varies from dark red to yellow. Furthermore, the variation of morphological characters correspond to environmental patterns.

Ganoderma sp. This image was created by user IG Safonov (IGSafonov) at Mushroom Observer, a source for mycological images.You can contact this user here.English - español - français - italiano - македонски - português - +/−

The hyphal system of Ganoderma is usually trimitic and in some cases it can be dimitic. Meanwhile, the generative hyphae are transparent, thin-walled, branched, septate or not, and are also subject. The skeletal hyphae are pigmented, thick-walled, and arboriform or aciculiform. The junctional hyphae are generally colorless with terminal branches.

For their part, basidia and basidiospores are considered the most important characters for the identification of species of basidiomycetes. Ganoderma basidia are relatively large and vary from flat to pyriform.

While the basidiospores are ovoid or elliptical-ovoid, they are sometimes cylindrical-ovoid, and always have a truncated apex. Also, the wall is not uniformly thickened, with the apex always thicker than the base.

In general, basidiospores are double-walled, elliptical, and brown, varying in size. Basidiospores have a transparent appendage on a rounded base, and vacuoles. The surface of the basidiospores is smooth or twisted and, in many cases, contains small and numerous superficial pits.

The number of fungal species belonging to the genus Ganoderma fluctuates between 70 and 90, being likely to find new taxa in poorly studied tropical regions. Of this number it is known that 80% are in temperate regions, half are from Southeast and East Asia and, between 20 to 40%, are Neotropical species.

characteristics

Macromorphology

The fruiting body of the species of the genus Ganoderma varies in shape and this can be from sessile, stipitate and imbricated or not. The surface color of the cap and the hymenophore varies from dark red, yellow and white.

The cap of a normal fruiting body is laterally attached to the stipe, but is eccentric, central, imbricated, and sessile. The stipe, on the other hand, may be relatively thickened at the back.

The varnished characteristic of the cap and stipe is common in the species of the genus Ganoderma. However, the species G. mongolicum does not have a varnished appearance on the surface of the cap.

Ganoderma (mushrooms). Source: pixabay.com

The color of the fruiting body varies from white, dark red, or dark brown. For its part, the morphology of the basidiocarp varies with respect to environmental conditions, being very sensitive to light. The stipe shows positive phototropism and under low light conditions the cap does not fully expand.

Micromorphology

Ganoderma fruiting body usually has hymenoderma or caracoderma and anamixoderma. While the hyphal system is usually trimitic, occasionally dimitic; while generative hyphae are transparent, thin-walled, branched, septate or not, and joined.

On the other hand, the hyphae of the skeleton are always pigmented, thick-walled, arboriform or aciculiform. The skeletal stems can end in flagelliform and branch in the processes of union.

Meanwhile, the junction hyphae are usually colorless with terminal branches. Some Ganoderma species such as G. lucidum and G. ungulatum show Bovista type junctional hyphae which are produced from skeletal or generative hyphae.

In Ganoderma, the only basidiospore is double-walled, ovoid or elliptical-ovoid, occasionally cylindrical-ovoid, and always truncated at the apex. The wall is not evenly thickened, with the apex thicker than the base.

Ganoderma basidiospores are brown and vary in size. In turn, the surfaces of the basidiospores are smooth or twisted and many have numerous small superficial holes.

Colonies

The color of the Ganoderma colonies varies from white to pale yellow on potato dextrose agar (PDA) medium. The colony becomes more yellowish as exposure to light increases.

Taxonomy

The genus Ganoderma is polyphyletic and is within the Ganodermataceae family and within the Aphyllophorales order. This genus is subdivided into three groups and also has two unclassified taxa.

Ganoderma mushrooms. Source: pixabay.com

Group I includes the G. lucidum sensu lato complex and is monophyletic or paraphyletic. This group is subdivided into four subgroups, which are: the G. lucidum complex, the G. resinceum complex, the G. curtisii complex, and the G. tropicum complex.

Group II includes species with varnished appearances other than G. lucidum and also species with unvarnished appearance. This group includes tropical and subtropical species. This group is subdivided into five subgroups: the palm clade, the subgroup II with three clades, the subgroup III, the subgroup IV, and the G. sinense complex.

Group III or group of the G. australe complex is characterized by not producing chlamydospores and by including the European species without varnishing appearance. The taxa that remain unresolved are: G. applanatum B., G.tsunodae, and G. colossum.

Habitat and distribution

Basidiomycete fungi of the genus Ganoderma have a worldwide distribution and grow on numerous conifers and deciduous palms. They are fungi that branch in the wood causing a number of diseases and economic problems in perennial tree crops.

Ganoderma species fulfill their ecological role by breaking down and degrading the dead matter of woody plants. Many of these fungi are saprophytes, but they can exploit the weakness of their hosts as parasites or as secondary parasites.

Ganoderma sp. Vengolis

It is estimated that between 60 and 80% of Ganoderma species have a varnished appearance and 10 to 30% are unvarnished. According to molecular markers, it is counted that 80% of the known species are from temperate regions, with almost half of the species from Southeast and East Asia, while 20 to 40% are Neotropical species.

Following a pattern of molecular weight markers, the Ganoderma clades respond to geographic distribution. This has made it possible to separate the Ganoderma clades of the new and old world, a link between the species of the southern hemisphere and a connection between the more tropical regions of the southern hemisphere and Southeast Asia.

According to molecular markers, it is estimated that there are 5 to 7 species of Ganoderma in Europe and 7 to 8 species in North America. Likewise, it has been determined that at least 12 species in temperate and subtropical regions of Asia, with the question that there are probably more species in this area.

Specificity

The fungi of the genus Ganoderma have a non-mutualistic relationship with several species of woody trees. Something that characterizes this group of basidiomycetes is the specificity with the host.

Thus, G. zonatum colonizes species of palm trees in America and Africa, but it is also found in Eucalyptus; G. miniatotinctum grows only on palm trees in South Asia and the Solomon Islands.

Thus, G. boninense is observed on many palm trees in Sri Lanka and on several Pacific islands. G. cupreum is paleotropical and colonizes palm trees and woody dicotyledons; G. xylonoides is restricted to Africa and inhabits woody dicots and palms; and G. tornatum is in Asia and some Pacific islands, colonizing only palm trees.

View of the hymenium of Ganoderma sp. This image was created by user Lanzz (Lanzz) at Mushroom Observer, a source for mycological images.You can contact this user here.English - español - français - italiano - македонски - português - +/−

Applications

Mushrooms of the genus Ganoderma are well known as species with medicinal properties. They are widely used in China, America, Japan, Korea, among other countries.

According to traditional Chinese medicine, Ganoderma mushrooms have the ability to enhance the body's resistance. In relation to this, channel tropism links the functions of the fungus to its corresponding internal organs.

The main Ganoderma species used are G. lucidum, G. sinensis, G. applanatum, G. tsugae, G. atrum, and G. formosanum. Ganoderma production is generally through artificial crops, which provide enough product to the growing market.

Drugs for the treatment of cancer, such as cisplatin and cyclophosphamide, can cause side effects such as nephrotoxicity, producing a decrease in the quality of life of patients.

That is why the use of immunotherapy against cancer has boomed in recent years. Given this, it has been found that the consumption of G. lucidum for 6 months increases the lymphoproliferative response induced by mitogens, in immunosuppressed children with tumors.

Representative species

Ganoderma lucidum is the representative species of the genus Ganoderma and is characterized by presenting a cap of 2 to 16 cm; on a stipe of 1 to 3 cm, and with a diameter of 1 to 3.5 cm. The color of the hat varies from white or cream-reddish to dark red.

Ganoderma. Source: pixabay.com

On the other hand, G. tsugae is white or pale yellow in color and with flocosy growths. While G. oregonense has the same characteristics, only that it forms a fruiting body under in vitro culture conditions.

References

1. Seo, GS, Kirk, PM 2000. Ganodermataceae: nomenclature and classification. In: Ganoderma Diseases of Perennial Crops pp 3-22.
2. Moncalvo, JM 2000. Systematics of Ganoderma. In: Ganoderma Diseases of Perennial. pp 23-45.
3. Miller, RNG, Holderness, M., Bridge, PD 2000. Molecular and morphological characterization of Ganoderma in oil-palm plantings. In: Ganoderma Diseases of Perennial. pp 159-176.
4. Mani, R., Upashna, C., Jaikumar, S., Rathi, B., Padma, MP 2016. Ganoderma lucidum: A Review with Special Emphasis on the Treatment of Various Cancer. J App Pharm 8: 228.
5. Cao, Y., Xu, X., Liu, S., Huang, L., Gu, J. 2018. Ganoderma: A Cancer Immunotherapy Review. Frontiers in Pharmacology, 9 (1217): 1-14.