Nephroma
| Nephroma | |
|---|---|
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| |
| Nephroma arcticum | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Lecanoromycetes |
| Order: | Peltigerales |
| Family: | Peltigeraceae |
| Genus: | Nephroma Ach. (1809) |
| Type species | |
| Nephroma arcticum | |
| Species | |
|
See text | |
| Synonyms[1] | |
Nephroma is a genus of medium to large foliose lichens. The genus has a widespread distribution.[2] They are sometimes called kidney lichens, named after the characteristic kidney-shaped apothecia that they produce on the lower surface of their lobe tips, which often curl upwards and thus are visible from above.[3] Sterile specimens that do not have apothecia can look somewhat like Melanelia, Peltigera, Platismatia, or Asahinea. Most species grow either on mossy ground or rocks, or on trees.[3]
All species of Nephroma contain cyanobacteria (in the genus Nostoc) as a photobiont, which allows the organism to fix nitrogen. In some species the cyanobacteria is the sole photobiont, while other species also contain a green alga photobiont (Coccomyxa) and the cyanobacteria is restricted to warty cephalodia on the upper or lower surface of the lichen.[3]
Description
[edit]Species of Nephroma have a stratified foliose thallus with a cortex that is well-developed on both the upper and lower surfaces. The fruit bodies (apothecia) are formed on the lower surface of the thallus, which is later curved backward to expose the hymenium (spore-bearing surface). Initially, the ascomata are immersed with a vegetative covering that splits open at later stages of development. In contrast to all other groups of Peltigerales, the asci of Nephroma have neither a gelatinous coat nor an iodine-positive apical ring. The brown ascospores are elongated, and have a crosswise partition (septa). Reproductive structures called soredia, isidia, or lobules are present in most species.[4]
Photobionts
[edit]Nephroma species form symbiotic relationships with photosynthetic partners (photobionts) that are essential to their survival. All Nephroma species contain cyanobacteria from the genus Nostoc, which not only provide products of photosynthesis but also fix nitrogen from the atmosphere, making it available to the lichen. Some species, known as tripartite lichens, also contain a green algal partner from the genus Coccomyxa, while others (bipartite lichens) contain only Nostoc.[5]
Research has shown that the Nostoc partners in Nephroma fall into two distinct genetic groups that correlate with the lichen's lifestyle. One group is found exclusively in bipartite species that typically grow on tree bark or rocks, while the other group occurs in tripartite species that usually grow on soil or among mosses. This pattern holds true across wide geographic areas – specimens of the same Nephroma species collected from different continents often contain nearly identical Nostoc strains. The green algal partners (Coccomyxa) in tripartite species show remarkably little genetic variation across different Nephroma species and geographic regions. These algae are closely related to some free-living species, including certain algae that live within the cells of Ginkgo biloba trees.[5]
Evolutionary studies have revealed that transitions between bipartite and tripartite forms in Nephroma's evolutionary history were complex events. When a species gained or lost the ability to partner with green algae, it also had to change the type of Nostoc it associated with, suggesting that these transitions required concurrent changes in both photobiont partnerships.[5]
Species
[edit]
- Nephroma arcticum (L.) Torss. (1843)
- Nephroma australe A.Rich. (1832)
- Nephroma bellum (Spreng.) Tuck. (1841)
- Nephroma cellulosum (Ach.) Ach. (1810)
- Nephroma expallidum (Nyl.) Nyl. (1865)
- Nephroma flavorhizinatum Q.Tian & H.Y.Wang (2011)[6]
- Nephroma helveticum Ach. (1810)
- Nephroma laevigatum Ach. (1814)
- Nephroma orvoi Timdal, M.Westb., Haugan, Hofton, Holien, Speed, Tønsberg & Bendiksby (2020)[7]
- Nephroma parile (Ach.) Ach. (1810)
- Nephroma resupinatum (L.) Ach. (1810)
- Nephroma rufum (C.Bab.) P.James (1983)
- Nephroma subhelveticum H.Y.Wang (2013)[8]
- Nephroma tangeriense (Maheu & A.Gillet) Gattefossé & Werner (1931)
Evolution and biogeography
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A 2011 phylogenetic study of Nephroma species in Macaronesia (the Azores, Madeira, and Canary Islands) revealed evidence of recent evolutionary radiation and neoendemism in the region. The study found that all five Macaronesian endemic species evolved relatively recently (within the last 19 million years) after the formation of the volcanic islands, rather than being ancient relict species. These endemic species belong to two distinct lineages, each associated with a widespread Holarctic species (N. parile or N. laevigatum). The research suggested that Macaronesia may have served as a source for subsequent colonisation of continental areas, with evidence of recent dispersal events from the islands to Western North America and the Mediterranean Basin. This represents the first documented case of neo-endemism in lichenised fungi from Macaronesia.[9]
Broader evolutionary studies have revealed complex patterns in how Nephroma species develop and maintain their symbiotic partnerships. While the fungal partners (mycobionts) of tripartite species do not form a single evolutionary group, their photosynthetic partners show strict patterns of association. This suggests that the evolution of different symbiotic forms in Nephroma was not a simple matter of gaining or losing a green algal partner. Instead, any shift between bipartite and tripartite forms required simultaneous changes in both the green algal and cyanobacterial partnerships.[5]
The genus also shows distinct ecological patterns in its evolution. Species that grow on trees or rocks (epiphytic or lithophytic species) consistently associate with one genetic group of Nostoc partners, while soil-dwelling species partner with a different group. This pattern holds true across continents, suggesting that these specific partnerships evolved early in the genus's history and have remained stable over long periods. Despite this specialisation in symbiotic partners, the fungal components of Nephroma species can show considerable genetic variation within species, particularly in temperate regions.[5]
Uses
[edit]Several species of Nephroma are restricted to pristine, old-growth forests, and thus are important indicator species that have already influenced some forest management decisions.[3] Nephroma occultum is listed as vulnerable in Canada by COSEWIC.
One species of Nephroma has been found to produce a brown dye,[10] while another is recorded as being used in Scotland to produce a blue dye for wool.[11] Nephroma arcticum is called kusskoak by the Yup'ik of Alaska, and it is traditionally eaten after being boiled with crushed fish eggs. A medicinal tea is also made from the lichen, and is reputed to be a powerful medicine to return strength to a person who is in a weak condition.[12] N. arcticum contains several antifreeze proteins that have been patented by the Dutch multinational corporation Unilever for their ability to modify the growth of ice crystals; these proteins have been used to improve the texture of low-fat ice cream.[13]
References
[edit]- ^ "Synonymy. Current Name: Nephroma Ach., in Luyken, Tentam. Histor. Lichen. Gen. Prim. Lin. Distrib. nov., Göttingae: 92 (1809)". Species Fungorum. Retrieved 24 December 2024.
- ^ Kirk PM, Cannon PF, Minter DW, Stalpers JA (2008). Dictionary of the Fungi (10th ed.). Wallingford: CABI. p. 467. ISBN 978-0-85199-826-8.
- ^ a b c d Sharnoff S, Brodo IM, Sharnoff SD (2001). Lichens of North America. New Haven, Connecticut: Yale University Press. ISBN 978-0-300-08249-4.
- ^ Lohtander, K.; Oksanen, I.; Rikkinen, J. (2002). "A phylogenetic study of Nephroma". Mycological Research. 106 (7): 777–787. doi:10.1017/S0953756202006068.
- ^ a b c d e Lohtander, Katileena; Oksanen, Ilona; Rikkinen, Jouko (2003). "Genetic diversity of green algal and cyanobacterial photobionts in Nephroma (Peltigerales)". The Lichenologist. 35 (4): 325–339. doi:10.1016/S0024-2829(03)00051-3.
- ^ Tian, Q.; Wang, L.S.; Wang, H.Y.; Zhao, Z.T. (2011). "A new species of Nephroma (Nephromataceae) from the Tibetan Plateau". Mycotaxon. 115: 281–285.
- ^ Timdal, E.; Westberg, M.; Haugan, R.; Hofton, T.H.; Holien, H.; Speed, J.D.M.; Tønsberg, T.; Bendiksby, M. (2020). "Integrative taxonomy reveals a new species, Nephroma orvoi, in the N. parile species complex (lichenized Ascomycota)". Graphis Scripta. 32 (4): 70–85.
- ^ Wang, H.Y.; Jiang, D.F.; Huang, Y.H.; Wang, P.M.; Li, T. (2013). "Study on the phylogeny of Nephroma helveticum and allied species". Mycotaxon. 125: 263–275.
- ^ Sérusiaux, Emmanuël; Villarreal A., Juan Carlos; Wheeler, Tim; Goffinet, Bernard (2011). "Recent origin, active speciation and dispersal for the lichen genus Nephroma (Peltigerales) in Macaronesia: Recent radiation of Nephroma in Macaronesia". Journal of Biogeography. 38 (6): 1138–1151. doi:10.1111/j.1365-2699.2010.02469.x.
- ^ Brough SG. (1984). "Dye characteristics of British Columbia forest lichens". Syesis. 17: 81–94.
- ^ Uphof JCT. (1959). Dictionary of Economic Plants. New York: Hafner Publishing Co.
- ^ Oswalt WH. (1957). "A western Eskimo ethnobotany". Anthropological Papers of the University of Alaska. 6 (1): 16–36.
- ^ Oksanen, I. (2006). "Ecological and biotechnological aspects of lichens". Applied Microbiology and Biotechnology. 73 (4): 723–34. doi:10.1007/s00253-006-0611-3. PMID 17082931.