''Solorina crocea'', commonly known as the orange chocolate chip lichen, is a species of

terricolous A terricolous lichen is a lichen that grows on the soil as a substrate. An example is some members of the genus ''Peltigera ''Peltigera'' is a genus of approximately 100 species of foliose lichens in the family Peltigeraceae. Commonly known as ...

(ground-dwelling) and

foliose Foliose lichen is one of the morphological classes of lichens, which are complex organisms that arise from the symbiotic relationship between fungi and a photosynthetic partner, typically algae. This partnership allows lichen to live in diverse ...

(leafy)

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.Peltigeraceae The Peltigeraceae are a family of lichens in the order Peltigerales. The Peltigeraceae, which contains 15 genera and about 600 species, has recently (2018) been emended to include the families Lobariaceae and Nephromataceae. Many Peltigeraceae sp ...

. The lichen, which was first formally described by

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in 1753, has an

arctic–alpine An Arctic–alpine taxon is one whose natural distribution includes the Arctic and more southerly mountain ranges, particularly the Alps. The presence of identical or similar taxa in both the tundra of the far north, and high mountain ranges much f ...

and

circumpolar distribution A circumpolar distribution is any range of a taxon that occurs over a wide range of longitudes but only at high latitudes; such a range therefore extends all the way around either the North Pole or the South Pole. Taxa that are also found in isolat ...

and occurs in Asia, Europe, North America, and New Zealand. It generally grows on the bare ground in sandy soils, often in moist soil near snow patches or

seepage Soil mechanics is a branch of soil physics and applied mechanics that describes the behavior of soils. It differs from fluid mechanics and solid mechanics in the sense that soils consist of a heterogeneous mixture of fluids (usually air and wat ...

areas. Although several

forms Form is the shape, visual appearance, or configuration of an object. In a wider sense, the form is the way something happens. Form also refers to: *Form (document), a document (printed or electronic) with spaces in which to write or enter data * ...

and

varieties Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

of the lichen have been proposed in its history, these are not considered to have any independent

taxonomic Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

significance. The colouration of ''Solorina crocea'' is quite distinct, making it readily identifiable: its upper

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms wer ...

surface is green, while both the undersurface and its internal

medulla Medulla or Medullary may refer to: Science * Medulla oblongata, a part of the brain stem * Renal medulla, a part of the kidney * Adrenal medulla, a part of the adrenal gland * Medulla of ovary, a stroma in the center of the ovary * Medulla of th ...

are bright orange. The orange colour results from a

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

called solorinic acid, one of several

secondary compounds Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the norma ...

that occur in the lichen. The thallus features dark brown discs, usually sunken into the surface, which are

apothecia An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mo ...

–where spores are produced. The lichen has both

blue-green algae Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

and

green algae The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...

as symbiotic partners (

photobiont A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.formally described to science by

in his influential 1753 work ''

Species Plantarum ' (Latin for "The Species of Plants") is a book by Carl Linnaeus, originally published in 1753, which lists every species of plant known at the time, classified into genera. It is the first work to consistently apply binomial names and was the ...

''. He named it ''Lichen crocea'', as it was his convention to classify all lichens in the

eponym An eponym is a person, a place, or a thing after whom or which someone or something is, or is believed to be, named. The adjectives which are derived from the word eponym include ''eponymous'' and ''eponymic''. Usage of the word The term ''epon ...

ously named genus ''Lichen''. His diagnosis made reference to the foliose thallus, the yellow underside (''croceum'' is

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for " saffron-coloured" or "yellow") and yellow veins on the upper side. To his understanding, the lichen occurred in

Lapponia Lapponia may refer to: * Laponia (historical province), a historical Swedish province * ''Lapponia'' (book), a 1673 ethnographic account of the region by Johannes Schefferus * Lapponia (train) The ''Lapponia'' was an express passenger train operate ...

, Switzerland, and

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...

. Although his 1753 work was the first official

description of the species, he had previously mentioned it in his works ''

Flora Svecica ''Flora Svecica'' ("Flora of Sweden", ed. 1, Stockholm, 1745; ed. 2 Stockholm, 1755) was written by Swedish botanist, physician, zoologist and naturalist Carl Linnaeus (1707–1778). This was the first full account of the plants growing in Swed ...

'' (1745), and ''

Flora Lapponica ''Flora Lapponica'' (Amsterdam, 1737) is an account of the plants of Lapland written by botanist, zoologist and naturalist Carl Linnaeus (1707-1788) following his expedition to Lapland. Over the period from 12 May 1732 to 10 September 1732, and ...

'' (1737). Later authors thought that the species was more appropriately classified in other genera, so in its taxonomic history, the

taxon In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

has been transferred to ''

Peltigera ''Peltigera'' is a genus of approximately 100 species of foliose lichens in the family Peltigeraceae. Commonly known as the dog or pelt lichens, species of ''Peltigera'' are often terricolous (growing on soil), but can also occur on moss, trees, ...

'' (

Georg Franz Hoffmann Georg Franz Hoffmann was a German botanist and lichenologist. He was born on 13 January 1760 in Marktbreit, Germany, and died on 17 March 1826 in Moscow, Russia. Professional career After graduating from the University of Erlangen in 1786, he w ...

, 1794), ''Peltidea'' (

Erik Acharius Erik Acharius (10 October 1757 – 14 August 1819) was a Swedish botanist who pioneered the taxonomy of lichens and is known as the "father of lichenology." Acharius was famously the last pupil of Carl Linnaeus. Life Acharius was born in ...

, 1803), '' Arthonia'' (Acharius, 1806), and ''

Parmelia Parmelia may refer to: * Parmelia (barque), the vessel that in 1829 transported the first settlers of the British colony of Western Australia * ''Parmelia'' (fungus), a genus of lichens with global distribution * Parmelia, Western Australia Pa ...

'' (

Kurt Sprengel Kurt Polycarp Joachim Sprengel (3 August 1766 – 15 March 1833) was a German botanist and physician who published an influential multivolume history of medicine, ''Versuch einer pragmatischen Geschichte der Arzneikunde'' (1792–99 in four vol ...

, 1827). The taxon is now known as the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of '' Solorina'', a genus

circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius. Not every polyg ...

by Acharius in 1808. Some

and

of ''Solorina crocea'' have been described, but these do not have independent taxonomic significance, and are assessed by

Index Fungorum ''Index Fungorum'' is an international project to index all formal names ( scientific names) in the fungus kingdom. the project is based at the Royal Botanic Gardens, Kew, one of three partners along with Landcare Research and the Institute of M ...

to be

synonymous A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

with the nominate taxon. These historical subtaxa include: *''Solorina crocea'' f. ''complicata'' *''Solorina crocea'' f. ''dubia'' *''Solorina crocea'' f. ''irregularis'' *''Solorina crocea'' var. ''complicata'' *''Solorina crocea'' var. ''eutipa''

Vernacular name A vernacular or vernacular language is in contrast with a "standard language". It refers to the language or dialect that is spoken by people that are inhabiting a particular country or region. The vernacular is typically the native language, n ...

s the species has acquired in North America include the "saffron-yellow solorina", and the "orange chocolate chip lichen"; the name refers to the large brownish fruitbodies (

ascomata An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mo ...

), which have an appearance resembling

chocolate chip Chocolate chips or chocolate morsels are small chunks of sweetened chocolate, used as an ingredient in a number of desserts (notably chocolate chip cookies and muffins), in trail mix and less commonly in some breakfast foods such as pancakes. ...

s. In the United Kingdom and Ireland, members of the genus are commonly known as "socket lichens", and the species is sometimes called "mountain saffron".

Description

The foliose thallus of ''Solorina crocea'' forms large rosettes comprising thick, rounded lobes; it typically measures up to broad, although measurements up to have been recorded. It is usually tightly pressed to its growing surface. The lobes comprising the thallus are wide with slightly upturned edges; their outline varies from irregular to rounded. The upper thallus surface, when moist, is olive green; in less hydrated conditions it becomes reddish brown. The lower thallus surface is bright orange with a

tomentose Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plant ...

texture and a somewhat reticulate pattern of brownish veins. Lacking a

cortex Cortex or cortical may refer to: Biology * Cortex (anatomy), the outermost layer of an organ ** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain'' *** Motor cortex, the regions of the cerebral cortex i ...

(an outer layer of compacted hyphae), it resembles a mat of orange-coloured, entangled threads. The medulla is orange.

Isidia An isidium is a vegetative reproductive structure present in some lichens. Isidia are outgrowths of the thallus surface, and are corticated (i.e., containing the outermost layer of the thallus), usually with a columnar structure, and consisting o ...

and

soredia Soredia are common reproductive structures of lichens. Lichens reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungal hyphae wrapped around cyanobacteria or gr ...

are absent. The distinctive colouration of the upper and lower surface make this lichen readily identifiable, although in the field the colour difference may not be easy to discern if the lichen is tightly attached to its substrate. The brown to reddish-brown

measure in diameter. They are either more or less level with the cortex or somewhat convex, rather than in concave depressions, as is the case with some other ''Solorina'' species. The

photobiont A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.green algae The green algae (singular: green alga) are a group consisting of the Prasinodermophyta and its unnamed sister which contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophytes) have emerged deep in the Charophyte alga as ...

lies above a patchy

cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

l layer. There are six to eight

ascospore An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or s ...

s in each

ascus An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera or s ...

of ''Solorina crocea''. They are brown with an

ellipsoid An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a surface that may be defined as the ...

shape, and contain a single transverse

septum In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatri ...

that divides the spore into two compartments. Based on a sampling of European specimens, the ascospores were measured to be an average of 11.0

μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

wide (ranging from 8.4 to 21.2 μm) by 39.0 μm long (ranging from 26.6 to 51.1 μm). The fine details of ascospore structure have been studied using scanning electron microscopy, revealing that there is a consistent, distinctive ornamentation in the spores of each of the most common arctic-alpine ''Solorina'' species. In ''S. crocea'', the spores are covered with irregularly shaped papillae (small pimple-like structures), but do not form form ridges or reticulations. The tips of the spores are rounded, and there is a slight constriction between the two cells. '' Solorina octospora'' has similar spore size and ornamentation as ''S. crocea'', but it does not have solorinic acid nor the subsequent orange-coloured medulla.

Similar species

'' Solorina crocoides'', described by

Vilmos Kőfaragó-Gyelnik Vilmos Kőfaragó-Gyelnik (March 30, 1906 – March 15, 1945) was a Hungarian botanist and lichenologist. Prior to earning his PhD in 1929 from Budapest University, he spent a year in Cairo to help organize a botanical museum. In 1930 he started ...

in 1930, was named for its similarity with ''Solorina crocea''. The sterile, non-fruiting version has similar chemical properties as its namesake; according to Krog and Swinscow, "The relationship between these two species needs further investigation". Some lichens collected at high elevations in Nepal are similar in overall morphology to ''Solorina crocea'', but feature some distinguishing characteristics: they have developments of the apothecia at the lobe margins reminiscent of lichens in the genus ''Peltigera'', there are soredia-like structures on the lobe margins that can later develop into isidia-like lobules, and they have a thick layer (100–125 μm) of cyanobacteria, while missing the green algal layer in many parts of the thallus. These lichens have not been formally described as a new species.

Chemistry

Several

lichen product Lichen products, also known as lichen substances, are organic compounds produced by a lichen. Specifically, they are secondary metabolites. Lichen products are represented in several different chemical classes, including terpenoids, orcinol deriva ...

s have been found in ''Solorina crocea'', including several

anthraquinone Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic organic compound with formula . Isomers include various quinone derivatives. The term anthraquinone however refers to the isomer, 9,10-anthraquinone (IUPAC: 9,10-dioxo ...

s ( solorinic acid, norsolorinic acid, averantin, averantin 6-''O''-monomethyl ether, and 4,4'-bissolorinic acid) and two

depside A depside is a type of polyphenolic compound composed of two or more monocyclic aromatic units linked by an ester bond. Depsides are most often found in lichens, but have also been isolated from higher plants, including species of the Ericaceae, L ...

s ( methyl gyrophorate and

gyrophoric acid Gyrophoric acid is a depside that can be found in the lichen ''Cryptothecia rubrocincta'' and in ''Xanthoparmelia pokomyi''. It can also be found in most of the species of the '' Actinogyra'', ''Lasallia'', and ''Umbilicaria'' genera Genus ( p ...

). The presence of solorinic acid causes the medulla and lower thallus surface to yield a positive K

spot test Spot analysis, spot test analysis, or spot test is a chemical test, a simple and efficient technique where analytic assays are executed in only one, or a few drops, of a chemical solution, preferably in a great piece of filter paper, without using ...

(K+, purple); this compound may also mask the results of the KC and C reactions. Solorinine is a novel

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

that was reported from the lichen in 1994. A

glycoside In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...

compound extracted from ''S. crocea'' and reported in 1994 – named 1-(''O''-α--glucopyranosyl)-3S,25R-hexacosanediol – was the first of its type (a "higher

alcoholic Alcoholism is, broadly, any drinking of alcohol that results in significant mental or physical health problems. Because there is disagreement on the definition of the word ''alcoholism'', it is not a recognized diagnostic entity. Predomin ...

glucoside A glucoside is a glycoside that is derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes. The name was o ...

") isolated from a lichen. Three of the anthraquinones from ''Solorina crocea''—norsolorinic acid, solorinic acid, and averantin 6-''O''-methyl ether—have been shown in laboratory experiments to

inhibit Inhibitor or inhibition may refer to: In biology * Enzyme inhibitor, a substance that binds to an enzyme and decreases the enzyme's activity * Reuptake inhibitor, a substance that increases neurotransmission by blocking the reuptake of a neurotra ...

the enzyme

monoamine oxidase Monoamine oxidases (MAO) () are a family of enzymes that catalyze the oxidation of monoamines, employing oxygen to clip off their amine group. They are found bound to the outer membrane of mitochondria in most cell types of the body. The first ...

Habitat and distribution

In North America its range extends from polar regions in alpine to subalpine habitats south to

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

and

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

. European countries in which the lichen has been recorded include Andorra, Austria, Bulgaria, Spain, Iceland, and Finland. In the UK, it occurs in the

Scottish Highlands The Highlands ( sco, the Hielands; gd, a’ Ghàidhealtachd , 'the place of the Gaels') is a historical region of Scotland. Culturally, the Highlands and the Lowlands diverged from the Late Middle Ages into the modern period, when Lowland Sco ...

, and it is represented by a single record from Ireland. Its distribution in Italy is limited to the high-altitude

Alps The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Sw ...

and the northern

Apennines The Apennines or Apennine Mountains (; grc-gre, links=no, Ἀπέννινα ὄρη or Ἀπέννινον ὄρος; la, Appenninus or – a singular with plural meaning;''Apenninus'' (Greek or ) has the form of an adjective, which wou ...

. In India, it is known from the

Himalayas The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 100 ...

regions (

Himachal Pradesh Himachal Pradesh (; ; "Snow-laden Mountain Province") is a state in the northern part of India. Situated in the Western Himalayas, it is one of the thirteen mountain states and is characterized by an extreme landscape featuring several peaks ...

and

Sikkim Sikkim (; ) is a state in Northeastern India. It borders the Tibet Autonomous Region of China in the north and northeast, Bhutan in the east, Province No. 1 of Nepal in the west and West Bengal in the south. Sikkim is also close to the Siligur ...

). Its range extends to the

Eastern Himalayas ] The Eastern Himalayas extend from eastern Nepal across Northeast India, Bhutan, the Tibet Autonomous Region to Yunnan in China and northern Myanmar. The climate of this region is influenced by the monsoon of South Asia from June to September. It ...

, as it has been recorded from

Xizang The Tibet Autonomous Region or Xizang Autonomous Region, often shortened to Tibet or Xizang, is a province-level autonomous region of the People's Republic of China in Southwest China. It was overlayed on the traditional Tibetan regions of Ü ...

Tibet Tibet (; ''Böd''; ) is a region in East Asia, covering much of the Tibetan Plateau and spanning about . It is the traditional homeland of the Tibetan people. Also resident on the plateau are some other ethnic groups such as Monpa people, ...

at an altitude of . In New Zealand, it has been collected from

Mount Peel Mount Peel is a mountain located in South Canterbury, New Zealand. It consists of three peaks, Mount Peel (often referred to as Big Mt Peel), Middle Mt Peel () and Little Mt Peel/Huatekerekere (). Mt Peel is tall and is owned by the Department ...

at an altitude of . Recorded habitats for the lichen include boulder fields, leached windswept ridges, and areas of

solifluction Solifluction is a collective name for gradual processes in which a mass moves down a slope ("mass wasting") related to freeze-thaw activity. This is the standard modern meaning of solifluction, which differs from the original meaning given to it ...

. In Iceland, ''Solorina crocea'' occurs in ''

Salix herbacea ''Salix herbacea'', the dwarf willow, least willow or snowbed willow, is a species of tiny creeping willow (family Salicaceae) adapted to survive in harsh arctic and subarctic environments. Distributed widely in alpine and arctic environments ar ...

'' snowbeds and north-facing slopes with abundant grasses and

sedge The Cyperaceae are a family of graminoid (grass-like), monocotyledonous flowering plants known as sedges. The family is large, with some 5,500 known species described in about 90 genera, the largest being the "true sedges" genus ''Carex'' wit ...

s. Generally, the lichen occurs on the bare ground in sandy soil. It grows in soils that are both acid-rich and base-rich as a result of

from late-lying snow patches.

Species interactions

''Solorina crocea'' is often infected by '' Rhagadostoma lichenicola'', a

lichenicolous A lichenicolous fungus is a parasitic fungus that only lives on lichen as the host. A lichenicolous fungus is not the same as the fungus that is the component of the lichen, which is known as a lichenized fungus. They are most commonly specific to ...

(lichen-dwelling) fungus. Infection results in the appearance of crowded blackish ascomata on the upper surface of the host thallus and a highly branched, dark

mycelium Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrate (biology), substrates. A typical single ...

below the fruitbodies. Its presence does not seem to affect the fertility of the lichen, suggesting that the fungus requires the function and integrity of the host to remain intact. The abundance of certain strains in the associated

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

l community of the lichen has been shown to be altered by the fungal infection. Bacteria normally associated with the lichen include members of the phyla

Acidobacteriota Acidobacteriota is a phylum of Gram-negative bacteria. Its members are physiologically diverse and ubiquitous, especially in soils, but are under-represented in culture. Description Members of this phylum are physiologically diverse, and can be ...

Planctomycetota The Planctomycetota are a phylum of widely distributed bacteria, occurring in both aquatic and terrestrial habitats. They play a considerable role in global carbon and nitrogen cycles, with many species of this phylum capable of anaerobic ammoniu ...

, and

Proteobacteria Pseudomonadota (synonym Proteobacteria) is a major phylum of Gram-negative bacteria. The renaming of phyla in 2021 remains controversial among microbiologists, many of whom continue to use the earlier names of long standing in the literature. The ...

. Another lichenicolous fungus, '' Talpapellis solorinae'', was described as a new species in 2015 from collections made in

North Caucasus The North Caucasus, ( ady, Темыр Къафкъас, Temır Qafqas; kbd, Ишхъэрэ Къаукъаз, İṩxhərə Qauqaz; ce, Къилбаседа Кавказ, Q̇ilbaseda Kavkaz; , os, Цӕгат Кавказ, Cægat Kavkaz, inh, ...

; it does not cause distinct damage to the infected host thallus. Other fungi that have been recorded infecting ''Solorina crocea'' include '' Arthonia peltigerina'', '' Cercidospora punctillata'', '' Corticifraga peltigerae'', '' Cercidospora lichenicola'', ''

Pyrenidium actinellum ''Pyrenidium'' is a genus of lichenicolous (lichen-dwelling) fungi. It is the only genus in the family Pyrenidiaceae. It has 13 species. Taxonomy The genus was circumscribed by Finnish lichenologist William Nylander in 1865, with '' Pyrenidium a ...

'', '' Stigmidium croceae'', '' Protothelenella croceae'', '' Thelocarpon epibolum'', and '' Pronectria robergei''. Infection by '' Stigmidium solorinarium'' results in the appearance of minute

perithecia An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mo ...

, while infection by '' Scutula tuberculosa'' will result in greyish to black

lecideine A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.

Research

Researchers have

cloned Cloning is the process of producing individual organisms with identical or virtually identical DNA, either by natural or artificial means. In nature, some organisms produce clones through asexual reproduction. In the field of biotechnology, c ...

a gene for

polyketide synthase Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynth ...

from ''Solorina crocea'' and transferred it to the filamentous fungus ''

Aspergillus oryzae ''Aspergillus oryzae'', also known as , is a filamentous fungus (a mold) used in East Asia to saccharify rice, sweet potato, and barley in the making of alcoholic beverages such as ''sake'' and '' shōchū'', and also to ferment soybeans for m ...

''. Lichen polyketides are of general research interest for their role in the biosynthesis of a great number of

secondary metabolite Secondary metabolites, also called specialised metabolites, toxins, secondary products, or natural products, are organic compounds produced by any lifeform, e.g. bacteria, fungi, animals, or plants, which are not directly involved in the norm ...

Laccase Laccases () are multicopper oxidases found in plants, fungi, and bacteria. Laccases oxidize a variety of phenolic substrates, performing one-electron oxidations, leading to crosslinking. For example, laccases play a role in the formation of lign ...

s from the lichen have been purified and studied. These enzymes depolymerize and decolorize

humic acid Humic substances (HS) are organic compounds that are important components of humus, the major organic fraction of soil, peat, and coal (and also a constituent of many upland streams, dystrophic lakes, and ocean water). For a long era in the 19th ...

s from soils, suggesting that the lichen is involved in the turnover and transformation of

organic matter Organic matter, organic material, or natural organic matter refers to the large source of carbon-based compounds found within natural and engineered, terrestrial, and aquatic environments. It is matter composed of organic compounds that have c ...

in the soil. A

metagenome Metagenomics is the study of genetic material recovered directly from environmental or clinical samples by a method called sequencing. The broad field may also be referred to as environmental genomics, ecogenomics, community genomics or microb ...

of ''Solorina crocea'' was reported in 2022. In addition to the fungal component of the lichen, the metagenome contained DNA from its green algal photobiont partner '' Coccomyxa solorinae'', from its

cyanobiont Cyanobionts are cyanobacteria that live in symbiosis with a wide range of organisms such as terrestrial or aquatic plants; as well as, algal and fungal species. They can reside within extracellular or intracellular structures of the host. In order ...

partner ''

Nostoc ''Nostoc'', also known as star jelly, troll’s butter, spit of moon, fallen star, witch's butter (not to be confused with the fungi commonly known as witches' butter), and witch’s jelly, is the most common genus of cyanobacteria found in vari ...

'', as well as from a bacterium (family

Caulobacteraceae Caulobacteraceae is a family of Pseudomonadota within the alpha subgroup.Garrity, George M.; Brenner, Don J.; Krieg, Noel R.; Staley, James T. (eds.) (2005). Bergey's Manual of Systematic Bacteriology, Volume Two: The Proteobacteria, Part C: The ...

), and a ''

Trichoderma ''Trichoderma'' is a genus of fungi in the family Hypocreaceae that is present in all soils, where they are the most prevalent culturable fungi. Many species in this genus can be characterized as opportunistic avirulent plant symbionts. This ref ...

'' fungus.

References

External links

* {{Taxonbar, from=Q1679102 Peltigerales Lichen species Lichens described in 1753 Lichens of China Lichens of Europe Lichens of Iceland Lichens of India Lichens of New Zealand Lichens of North America Taxa named by Carl Linnaeus