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{{Short description|Species of fungus in the family Teloschistaceae}}
{{Short description|Species of lichen-forming fungus}}
{{Speciesbox
{{Speciesbox
| image = Xanthoria aureola 104935984.jpg
| image = Xanthoria aureola 104935984.jpg
| taxon = Xanthoria aureola
| taxon = Xanthoria aureola
| authority = [[Erik Acharius|Acharius]] & Erichsen, 1930
| authority = ([[Erik Acharius|Acharius]]) Erichsen (1930)
| synonyms = *''Parmelia aureola'' {{au|Ach. (1810)}}
}}
}}


'''''Xanthoria aureola''''', commonly known as the '''seaside sunburst lichen''', is a lichenized species of fungus in the family [[Teloschistaceae]] and phylum [[Ascomycota]].<ref name="auto">{{Cite web |title=Catalogue of Life : Xanthoria aureola (Ach.) Erichsen |url=http://www.catalogueoflife.org/annual-checklist/2019/details/species/id/3b5ff00b15d3ba509d10eece43bde9af |access-date=2023-05-03 |website=www.catalogueoflife.org}}</ref> ''X. aureola'' can be recognized by its bright yellow-orange pigmentation and abundant strap-shaped lobes.<ref name=":0">{{Cite journal |last1=Lindblom |first1=Louise |last2=Ekman |first2=Stefan |date=February 2005 |title=Molecular evidence supports the distinction between Xanthoria parietina and X. aureola (Teloschistaceae, lichenized Ascomycota) |url=http://dx.doi.org/10.1017/s0953756204001790 |journal=Mycological Research |volume=109 |issue=2 |pages=187–199 |doi=10.1017/s0953756204001790 |pmid=15839102 |issn=0953-7562}}</ref>  It is usually found growing on exposed, nutrient-rich rocks in sunny, maritime habitats.<ref name=":1">{{Cite web |last=Fiorentino |first=J. |date=2011 |title=The genus Xanthoria (Teloschistaceae, lichenised Ascomycota) in the Maltese Islands |url=https://www.semanticscholar.org/paper/The-genus-Xanthoria-(Teloschistaceae%2C-lichenised-in-Fiorentino/fd55fd80d9fb7076a4e6eda08f08e4429dde460c |access-date=2023-05-03 |website=www.semanticscholar.org |s2cid=90539006 |language=en}}</ref><ref name=":2">{{Cite journal |last1=Bednar |first1=T. W. |last2=Smith |first2=D. C. |date=April 1966 |title=VI. Preliminary Studies of Photosynthesis and Carbohydrate Metabolism of the Lichen Xanthoria aureola |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.1966.tb06353.x |journal=New Phytologist |language=en |volume=65 |issue=2 |pages=211–220 |doi=10.1111/j.1469-8137.1966.tb06353.x |issn=0028-646X}}</ref>  It is largely restricted to European coasts, stretching from Portugal to Norway.<ref name="auto" />
'''''Xanthoria aureola''''', commonly known as the '''seaside sunburst lichen''', is a lichenized species of fungus in the family [[Teloschistaceae]] and phylum [[Ascomycota]].<ref name="auto">{{Cite web |title=Catalogue of Life : Xanthoria aureola (Ach.) Erichsen |url=http://www.catalogueoflife.org/annual-checklist/2019/details/species/id/3b5ff00b15d3ba509d10eece43bde9af |access-date=2023-05-03 |website=www.catalogueoflife.org}}</ref> ''X. aureola'' can be recognized by its bright yellow-orange pigmentation and abundant strap-shaped {{lichengloss|lobes}}.<ref name=":0">{{Cite journal |last1=Lindblom |first1=Louise |last2=Ekman |first2=Stefan |year=2005 |title=Molecular evidence supports the distinction between ''Xanthoria parietina'' and ''X. aureola'' (Teloschistaceae, lichenized Ascomycota) |url=http://dx.doi.org/10.1017/s0953756204001790 |journal=Mycological Research |volume=109 |issue=2 |pages=187–199 |doi=10.1017/s0953756204001790 |pmid=15839102 |issn=0953-7562}}</ref>&nbsp; It is usually found growing on exposed, nutrient-rich rocks in sunny, maritime habitats.<ref name=":1">{{Cite journal |last=Fiorentino |first=Jennifer |year=2011 |title=The genus ''Xanthoria'' (Teloschistaceae, lichenised Ascomycota) in the Maltese Islands |url=https://www.um.edu.mt/library/oar//handle/123456789/15408 |journal=The Central Mediterranean Naturalist |volume=5 |issue=3–4 |pages=9–17 |s2cid=90539006}}</ref><ref name=":2">{{Cite journal |last1=Bednar |first1=T. W. |last2=Smith |first2=D. C. |year=1966 |title=VI. Preliminary Studies of Photosynthesis and Carbohydrate Metabolism of the Lichen ''Xanthoria aureola'' |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.1966.tb06353.x |journal=New Phytologist |volume=65 |issue=2 |pages=211–220 |doi=10.1111/j.1469-8137.1966.tb06353.x |issn=0028-646X}}</ref>&nbsp; It is largely restricted to European coasts, stretching from Portugal to Norway.<ref name="auto" />


== Taxonomy ==
== Taxonomy ==
''Xanthoria aureola'' was first described as ''Parmelia aureola'' in 1809; it was found on seaside rocks in Boshuslän, Sweden and named by Acharius.<ref name=":0" />  In 1930, Erichsen transferred ''P. aureola'' to the genus ''Xanthoria'' at the species rank, resulting in the accepted binomial ''X. aureola.''<ref name=":0" />  However, from 1965 to 1984, the classification ''X. aureola'' was mistakenly applied to ''X. calcicola'', a closely related species first described in 1937.<ref name=":0" />  Within the genus ''Xanthoria'', DNA sequencing has confirmed that ''X. aureola'' is most closely related to ''X. calcicola'' and more distantly related to ''X. parietina.''<ref name=":3">{{Cite journal |last1=Lindblom |first1=Louise |last2=Ekman |first2=Stefan |date=2005-02-01 |title=Molecular evidence supports the distinction between Xanthoria parietina and X. aureola (Teloschistaceae, lichenized Ascomycota) |url=https://www.sciencedirect.com/science/article/pii/S0953756208613957 |journal=Mycological Research |language=en |volume=109 |issue=2 |pages=187–199 |doi=10.1017/S0953756204001790 |pmid=15839102 |issn=0953-7562}}</ref>  
''Xanthoria aureola'' was first [[species description|described]] as ''Parmelia aureola'' in 1809; it was found on seaside rocks in Boshuslän, Sweden and named by [[Erik Acharius]].<ref name=":0" />&nbsp; In 1930, Christian Erichsen transferred ''P. aureola'' to the genus ''[[Xanthoria]]'' at the species rank, resulting in the accepted binomial ''X. aureola.''<ref name=":0" />&nbsp; However, from 1965 to 1984, the classification ''X. aureola'' was mistakenly applied to ''X. calcicola'', a closely related species first described in 1937.<ref name=":0" />&nbsp; Within the genus ''Xanthoria'', DNA sequencing has confirmed that ''X. aureola'' is most closely related to ''X. calcicola'' and more distantly related to ''X. parietina.''<ref name=":3">{{Cite journal |last1=Lindblom |first1=Louise |last2=Ekman |first2=Stefan |year=2005 |title=Molecular evidence supports the distinction between ''Xanthoria parietina'' and ''X. aureola'' (Teloschistaceae, lichenized Ascomycota) |url=https://www.sciencedirect.com/science/article/pii/S0953756208613957 |journal=Mycological Research |language=en |volume=109 |issue=2 |pages=187–199 |doi=10.1017/S0953756204001790 |pmid=15839102 |issn=0953-7562}}</ref> &nbsp;


== Habitat and distribution ==
== Habitat and distribution ==
''X. aureola'' grows on exposed maritime rocks in sunny areas.<ref name=":1" /><ref name=":2" />  It generally grows on nutrient-rich, siliceous rocks, as well as limestone and lignum.<ref name=":0" /><ref name=":1" />  It is found on European coasts 0–150 meters above sea level.<ref name=":0" />  Some countries in which ''X. aureola'' is commonly found include Spain, Portugal, France, Ireland, Denmark, Sweden, Norway, Italy, and the UK.<ref name="auto" />  It usually grows next to ''X. parietina'', but in greater abundance and on exposed rock.<ref name=":0" /> 
''Xanthoria aureola'' grows on exposed maritime rocks in sunny areas.<ref name=":1" /><ref name=":2" />&nbsp; It generally grows on nutrient-rich, siliceous rocks, as well as limestone and lignum.<ref name=":0" /><ref name=":1" />&nbsp; It is found on European coasts 0–150 meters above sea level.<ref name=":0" />&nbsp; Some countries in which ''X. aureola'' is commonly found include Spain, Portugal, France, Ireland, Denmark, Sweden, Norway, Italy, and the UK.<ref name="auto" />&nbsp; It usually grows next to ''X. parietina'', but in greater abundance and on exposed rock.<ref name=":0" />&nbsp;


== Morphology ==
== Description ==
[[File:Xanthoria aureola 23982461.jpg|thumb|''X. aureola'' apothecia on a rock in Tórshavn, Faroe Islands.]]
[[File:Xanthoria aureola 23982461.jpg|thumb|''X. aureola'' apothecia on a rock in Tórshavn, Faroe Islands.]]
The thallus of ''X. aureola'' is bright yellow, orange, or orange-red with a foliose morphology.<ref name=":0" />  It is characterized by overlapping strap-shaped lobes that exhibit dichotomous branching.<ref name=":0" /><ref name=":1" />  When treated with potassium hydroxide, the thallus turns deep red (K+ red).<ref name=":0" />  Average lobe width is 0.46-1.6&nbsp;mm and average lobe thickness is 135 μm.<ref name=":1" />  ''X. aureola'' has a lower cortex, although no true rhizines.<ref name=":0" />  There are scattered hapters on the cream-colored underside of thick lobes.<ref name=":1" />  The upper cortex is rough with a layer of crystals, dotted with few apothecia.<ref name=":0" />  Chemicals such as parietin, fallacina, emodin, teloistin, and parietinic acid are present, as well as the dominant carotenoid mutatoxanthin.<ref name=":0" /><ref name=":4">{{Cite journal |last=Czeczuga |first=B. |date=1983-11-18 |title=Mutatoxanthin, the dominant carotenoid in lichens of the Xanthoria genus |url=https://dx.doi.org/10.1016/0305-1978%2883%2990032-7 |journal=Biochemical Systematics and Ecology |language=en |volume=11 |issue=4 |pages=329–331 |doi=10.1016/0305-1978(83)90032-7 |issn=0305-1978}}</ref>  Mutatoxanthin, a carotenoid important in the protection of the photosynthetic component against harsh sunlight, represents 94.4% of the total carotenoid content in ''X. aureola''.<ref name=":4" />  Of all ''Xanthori''a species, ''X. aureola'' contains the most mutatoxanthin.<ref name=":4" />  
The thallus of ''X. aureola'' is bright yellow, orange, or orange-red with a foliose morphology.<ref name=":0" />&nbsp; It is characterized by overlapping strap-shaped lobes that exhibit dichotomous branching.<ref name=":0" /><ref name=":1" />&nbsp; When treated with potassium hydroxide, the thallus turns deep red (K+ red).<ref name=":0" />&nbsp; Average lobe width is 0.46-1.6&nbsp;mm and average lobe thickness is 135 μm.<ref name=":1" />&nbsp; ''X. aureola'' has a lower cortex, although no true rhizines.<ref name=":0" />&nbsp; There are scattered hapters on the cream-colored underside of thick lobes.<ref name=":1" />&nbsp; The upper cortex is rough with a layer of crystals, dotted with few apothecia.<ref name=":0" />&nbsp; Chemicals such as parietin, fallacina, emodin, teloistin, and parietinic acid are present, as well as the dominant carotenoid mutatoxanthin.<ref name=":0" /><ref name=":4">{{Cite journal |last=Czeczuga |first=B. |year=1983 |title=Mutatoxanthin, the dominant carotenoid in lichens of the Xanthoria genus |url=https://dx.doi.org/10.1016/0305-1978%2883%2990032-7 |journal=Biochemical Systematics and Ecology |language=en |volume=11 |issue=4 |pages=329–331 |doi=10.1016/0305-1978(83)90032-7 |issn=0305-1978|url-access=subscription }}</ref>&nbsp; Mutatoxanthin, a carotenoid important in the protection of the photosynthetic component against harsh sunlight, represents 94.4% of the total carotenoid content in ''X. aureola''.<ref name=":4" />&nbsp; Of all ''Xanthori''a species, ''X. aureola'' contains the most mutatoxanthin.<ref name=":4" /> &nbsp;


''X. aureola'' is often confused with closely related species ''X. parietina'' and ''X. calcicola''.<ref name=":3" />  In comparison, ''X. aureola'' has a brighter thallus color as well as a considerably thicker medulla (187&nbsp;mm compared to 114–120&nbsp;mm).<ref name=":3" />  Additionally, the rough upper surface of ''X. aureola'' contains few apothecia and does not contain soredia or isidia; laminar structures are lobules.<ref name=":0" /><ref name=":3" />  Last, substrate is important: ''X. aureola'' is restricted to seashore rocks, while ''X. calcicola'' and ''X. parietinia'' can be found on almost any rock or wall.<ref name=":3" />    
''X. aureola'' is often confused with closely related species ''X. parietina'' and ''X. calcicola''.<ref name=":3" />&nbsp; In comparison, ''X. aureola'' has a brighter thallus color as well as a considerably thicker medulla (187&nbsp;mm compared to 114–120&nbsp;mm).<ref name=":3" />&nbsp; Additionally, the rough upper surface of ''X. aureola'' contains few apothecia and does not contain soredia or isidia; laminar structures are lobules.<ref name=":0" /><ref name=":3" />&nbsp; Last, substrate is important: ''X. aureola'' is restricted to seashore rocks, while ''X. calcicola'' and ''X. parietinia'' can be found on almost any rock or wall.<ref name=":3" /> &nbsp; &nbsp;


== Ecology ==
== Ecology ==
The algal symbiont in ''X. aureola'' is ''[[Trebouxia]]''.<ref name=":5">{{Cite journal |last1=Richardson |first1=D. H. S. |last2=Smith |first2=D. C. |date=January 1968 |title=Lichen Physiology. X. The Isolated Algal and Fungal Symbionts of Xanthoria aureola |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1469-8137.1968.tb05455.x |journal=New Phytologist |language=en |volume=67 |issue=1 |pages=69–77 |doi=10.1111/j.1469-8137.1968.tb05455.x |issn=0028-646X}}</ref>  ''Trebouxia'' fixes <sup>14</sup>C mainly into ribitol during photosynthesis; approximately 80% is ribitol, 5% is sucrose, 4% is organic acids, and 9% is baseline CH.<ref name=":5" /><ref name=":6">{{Citation |last=Richardson |first=D. H. S. |title=Chapter 8 - Photosynthesis and Carbohydrate Movement |date=1973-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9780120449507500131 |work=The Lichens |pages=249–288 |editor-last=Ahmadjian |editor-first=VERNON |access-date=2023-05-03 |publisher=Academic Press |language=en |doi=10.1016/b978-0-12-044950-7.50013-1 |isbn=978-0-12-044950-7 |editor2-last=Hale |editor2-first=MASON E.}}</ref>  Therefore, ribitol is the main way in which carbohydrates are transferred among symbionts in the thallus.<ref name=":5" />  The flow of carbon from ''Trebouxia'' to the fungus is efficient, with a steady rate of 15 minutes.<ref name=":2" />  Little carbon (~2%) is stored as insoluble compounds in the thallus.<ref name=":2" /><ref name=":6" />  The mean chlorophyll content per algal cell is 3.0-4.8 x 10<sup>−6</sup> mg.<ref name=":6" />  
The algal symbiont in ''X. aureola'' is ''[[Trebouxia]]''.<ref name=":5">{{Cite journal |last1=Richardson |first1=D. H. S. |last2=Smith |first2=D. C. |year=1968 |title=Lichen Physiology. X. The Isolated Algal and Fungal Symbionts of Xanthoria aureola |journal=New Phytologist |language=en |volume=67 |issue=1 |pages=69–77 |doi=10.1111/j.1469-8137.1968.tb05455.x |issn=0028-646X|doi-access=free }}</ref>&nbsp; ''Trebouxia'' fixes <sup>14</sup>C mainly into ribitol during photosynthesis; approximately 80% is ribitol, 5% is sucrose, 4% is organic acids, and 9% is baseline CH.<ref name=":5" /><ref name=":6">{{Citation |last=Richardson |first=D. H. S. |title=Photosynthesis and Carbohydrate Movement |year=1973 |url=https://www.sciencedirect.com/science/article/pii/B9780120449507500131 |work=The Lichens |pages=249–288 |editor-last=Ahmadjian |editor-first=VERNON |access-date=2023-05-03 |publisher=Academic Press |language=en |doi=10.1016/b978-0-12-044950-7.50013-1 |isbn=978-0-12-044950-7 |editor2-last=Hale |editor2-first=MASON E.|url-access=subscription }}</ref>&nbsp; Therefore, ribitol is the main way in which carbohydrates are transferred among symbionts in the thallus.<ref name=":5" />&nbsp; The flow of carbon from ''Trebouxia'' to the fungus is efficient, with a steady rate of 15 minutes.<ref name=":2" />&nbsp; Little carbon (~2%) is stored as insoluble compounds in the thallus.<ref name=":2" /><ref name=":6" />&nbsp; The mean chlorophyll content per algal cell is 3.0-4.8 x 10<sup>−6</sup> mg.<ref name=":6" /> &nbsp;


Environmental disturbance plays an important role in efficiency and productivity.  Lichen species are often used to monitor pollution since they are sensitive to SO<sub>2</sub>, heavy metals, salt, and high levels of UV.<ref name=":7">{{Cite journal |last1=Kováčik |first1=Jozef |last2=Klejdus |first2=Bořivoj |last3=Štork |first3=František |last4=Malčovská |first4=Silvia |date=2011-06-02 |title=Sensitivity of Xanthoria parietina to UV-A: Role of metabolic modulators |url=https://www.sciencedirect.com/science/article/pii/S1011134411001047 |journal=Journal of Photochemistry and Photobiology B: Biology |language=en |volume=103 |issue=3 |pages=243–250 |doi=10.1016/j.jphotobiol.2011.04.002 |pmid=21531571 |issn=1011-1344}}</ref>  Environmental stress (i.e., increased UV light) enhances the creation of reactive oxygen species (ROS), including superoxide and hydrogen peroxide.<ref name=":7" />  The formation of ROS was higher in all treatments with greater UV, although ''Xanthoria'' species showed the greatest resilience under harsh light conditions.<ref name=":7" />  Additionally, pre-treatment with salicylic acid coupled with high-energy radiation resulted in fewer amino acids, notably Glu, Tyr, and Pro.<ref name=":7" />  Amino acids are essential in the formation of proteins and basic biochemical functions.  Another experiment underscored the sensitivity of ''X. aureola'' to high concentrations of heavy metals and salt.<ref name=":8">{{Cite journal |last1=Yemets |first1=Olena |last2=Gauslaa |first2=Yngvar |last3=Solhaug |first3=Knut Asbjørn |date=2015-08-01 |title=Monitoring with lichens – Conductivity methods assess salt and heavy metal damage more efficiently than chlorophyll fluorescence |url=https://www.sciencedirect.com/science/article/pii/S1470160X15001399 |journal=Ecological Indicators |language=en |volume=55 |pages=59–64 |doi=10.1016/j.ecolind.2015.03.015 |issn=1470-160X}}</ref>  Membrane integrity was measured via conductivity and potential photosystem II (PSII) efficiency (Fv/Fm), with the former being a more accurate measure.<ref name=":8" />  High UV, salt, and heavy metal concentrations increased membrane dissolution and electrolyte leakage.<ref name=":8" />  ''X. aureola'' was more resistant to salt than other lichenized species ''Lobaria pulmonaria'' and ''Parmelia sulcata''.<ref name=":8" />  Copper and zinc had no effect on Fv/Fm of ''X. aureola''.<ref name=":8" />  It is likely that zinc and iodine in seawater protect ''Trebouxia'' and increase resistance to high salt and UV.<ref name=":8" />  Increasing environmental stress may exacerbate ROS formation and electrolyte leakage.  
Environmental disturbance plays an important role in efficiency and productivity.&nbsp; Lichen species are often used to monitor pollution since they are sensitive to SO<sub>2</sub>, heavy metals, salt, and high levels of UV.<ref name=":7">{{Cite journal |last1=Kováčik |first1=Jozef |last2=Klejdus |first2=Bořivoj |last3=Štork |first3=František |last4=Malčovská |first4=Silvia |year=2011 |title=Sensitivity of ''Xanthoria parietina'' to UV-A: Role of metabolic modulators |url=https://www.sciencedirect.com/science/article/pii/S1011134411001047 |journal=Journal of Photochemistry and Photobiology B: Biology |language=en |volume=103 |issue=3 |pages=243–250 |doi=10.1016/j.jphotobiol.2011.04.002 |pmid=21531571 |issn=1011-1344}}</ref>&nbsp; Environmental stress (i.e., increased UV light) enhances the creation of reactive oxygen species (ROS), including superoxide and hydrogen peroxide.<ref name=":7" />&nbsp; The formation of ROS was higher in all treatments with greater UV, although ''Xanthoria'' species showed the greatest resilience under harsh light conditions.<ref name=":7" />&nbsp; Additionally, pre-treatment with salicylic acid coupled with high-energy radiation resulted in fewer amino acids, notably Glu, Tyr, and Pro.<ref name=":7" />&nbsp; Amino acids are essential in the formation of proteins and basic biochemical functions.&nbsp; Another experiment underscored the sensitivity of ''X. aureola'' to high concentrations of heavy metals and salt.<ref name=":8">{{Cite journal |last1=Yemets |first1=Olena |last2=Gauslaa |first2=Yngvar |last3=Solhaug |first3=Knut Asbjørn |year=2015 |title=Monitoring with lichens – Conductivity methods assess salt and heavy metal damage more efficiently than chlorophyll fluorescence |url=https://www.sciencedirect.com/science/article/pii/S1470160X15001399 |journal=Ecological Indicators |language=en |volume=55 |pages=59–64 |doi=10.1016/j.ecolind.2015.03.015 |issn=1470-160X|url-access=subscription }}</ref>&nbsp; Membrane integrity was measured via conductivity and potential photosystem II (PSII) efficiency (Fv/Fm), with the former being a more accurate measure.<ref name=":8" />&nbsp; High UV, salt, and heavy metal concentrations increased membrane dissolution and electrolyte leakage.<ref name=":8" />&nbsp; ''X. aureola'' was more resistant to salt than other lichenized species ''Lobaria pulmonaria'' and ''Parmelia sulcata''.<ref name=":8" />&nbsp; Copper and zinc had no effect on Fv/Fm of ''X. aureola''.<ref name=":8" />&nbsp; It is likely that zinc and iodine in seawater protect ''Trebouxia'' and increase resistance to high salt and UV.<ref name=":8" />&nbsp; Increasing environmental stress may exacerbate ROS formation and electrolyte leakage. &nbsp;

== Cultural significance ==
''Xanthoria'' species have traditionally been used as a treatment for jaundice, menstrual cramps, and kidney disorders.<ref name=":9">{{Cite journal |last1=Basile |first1=Adriana |last2=Rigano |first2=Daniela |last3=Loppi |first3=Stefano |last4=Di Santi |first4=Annalisa |last5=Nebbioso |first5=Angela |last6=Sorbo |first6=Sergio |last7=Conte |first7=Barbara |last8=Paoli |first8=Luca |last9=De Ruberto |first9=Francesca |last10=Molinari |first10=Anna Maria |last11=Altucci |first11=Lucia |last12=Bontempo |first12=Paola |date=April 2015 |title=Antiproliferative, Antibacterial and Antifungal Activity of the Lichen Xanthoria parietina and Its Secondary Metabolite Parietin |journal=International Journal of Molecular Sciences |language=en |volume=16 |issue=4 |pages=7861–7875 |doi=10.3390/ijms16047861 |issn=1422-0067 |pmc=4425054 |pmid=25860944 |doi-access=free }}</ref>  It is also used as an analgesic in eastern Andalucia and Spain.<ref name=":9" /> 


==References==
==References==
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⚫
[[Category:Lichens described in 1930]]
[[Category:Teloschistales]]
[[Category:Teloschistales]]
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[[Category:Lichens described in 1810]]
[[Category:Lichen species]]
[[Category:Lichen species]]
[[Category:Lichens of Europe]]
[[Category:Taxa named by Erik Acharius]]

Latest revision as of 08:04, 25 February 2024

Xanthoria aureola
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Teloschistales
Family: Teloschistaceae
Genus: Xanthoria
Species:
X. aureola
Binomial name
Xanthoria aureola
(Acharius) Erichsen (1930)
Synonyms
  • Parmelia aureola Ach. (1810)

Xanthoria aureola, commonly known as the seaside sunburst lichen, is a lichenized species of fungus in the family Teloschistaceae and phylum Ascomycota.[1] X. aureola can be recognized by its bright yellow-orange pigmentation and abundant strap-shaped lobes.[2]  It is usually found growing on exposed, nutrient-rich rocks in sunny, maritime habitats.[3][4]  It is largely restricted to European coasts, stretching from Portugal to Norway.[1]

Taxonomy[edit]

Xanthoria aureola was first described as Parmelia aureola in 1809; it was found on seaside rocks in Boshuslän, Sweden and named by Erik Acharius.[2]  In 1930, Christian Erichsen transferred P. aureola to the genus Xanthoria at the species rank, resulting in the accepted binomial X. aureola.[2]  However, from 1965 to 1984, the classification X. aureola was mistakenly applied to X. calcicola, a closely related species first described in 1937.[2]  Within the genus Xanthoria, DNA sequencing has confirmed that X. aureola is most closely related to X. calcicola and more distantly related to X. parietina.[5]  

Habitat and distribution[edit]

Xanthoria aureola grows on exposed maritime rocks in sunny areas.[3][4]  It generally grows on nutrient-rich, siliceous rocks, as well as limestone and lignum.[2][3]  It is found on European coasts 0–150 meters above sea level.[2]  Some countries in which X. aureola is commonly found include Spain, Portugal, France, Ireland, Denmark, Sweden, Norway, Italy, and the UK.[1]  It usually grows next to X. parietina, but in greater abundance and on exposed rock.[2] 

Description[edit]

X. aureola apothecia on a rock in Tórshavn, Faroe Islands.

The thallus of X. aureola is bright yellow, orange, or orange-red with a foliose morphology.[2]  It is characterized by overlapping strap-shaped lobes that exhibit dichotomous branching.[2][3]  When treated with potassium hydroxide, the thallus turns deep red (K+ red).[2]  Average lobe width is 0.46-1.6 mm and average lobe thickness is 135 μm.[3]  X. aureola has a lower cortex, although no true rhizines.[2]  There are scattered hapters on the cream-colored underside of thick lobes.[3]  The upper cortex is rough with a layer of crystals, dotted with few apothecia.[2]  Chemicals such as parietin, fallacina, emodin, teloistin, and parietinic acid are present, as well as the dominant carotenoid mutatoxanthin.[2][6]  Mutatoxanthin, a carotenoid important in the protection of the photosynthetic component against harsh sunlight, represents 94.4% of the total carotenoid content in X. aureola.[6]  Of all Xanthoria species, X. aureola contains the most mutatoxanthin.[6]  

X. aureola is often confused with closely related species X. parietina and X. calcicola.[5]  In comparison, X. aureola has a brighter thallus color as well as a considerably thicker medulla (187 mm compared to 114–120 mm).[5]  Additionally, the rough upper surface of X. aureola contains few apothecia and does not contain soredia or isidia; laminar structures are lobules.[2][5]  Last, substrate is important: X. aureola is restricted to seashore rocks, while X. calcicola and X. parietinia can be found on almost any rock or wall.[5]    

Ecology[edit]

The algal symbiont in X. aureola is Trebouxia.[7]  Trebouxia fixes 14C mainly into ribitol during photosynthesis; approximately 80% is ribitol, 5% is sucrose, 4% is organic acids, and 9% is baseline CH.[7][8]  Therefore, ribitol is the main way in which carbohydrates are transferred among symbionts in the thallus.[7]  The flow of carbon from Trebouxia to the fungus is efficient, with a steady rate of 15 minutes.[4]  Little carbon (~2%) is stored as insoluble compounds in the thallus.[4][8]  The mean chlorophyll content per algal cell is 3.0-4.8 x 10−6 mg.[8]  

Environmental disturbance plays an important role in efficiency and productivity.  Lichen species are often used to monitor pollution since they are sensitive to SO2, heavy metals, salt, and high levels of UV.[9]  Environmental stress (i.e., increased UV light) enhances the creation of reactive oxygen species (ROS), including superoxide and hydrogen peroxide.[9]  The formation of ROS was higher in all treatments with greater UV, although Xanthoria species showed the greatest resilience under harsh light conditions.[9]  Additionally, pre-treatment with salicylic acid coupled with high-energy radiation resulted in fewer amino acids, notably Glu, Tyr, and Pro.[9]  Amino acids are essential in the formation of proteins and basic biochemical functions.  Another experiment underscored the sensitivity of X. aureola to high concentrations of heavy metals and salt.[10]  Membrane integrity was measured via conductivity and potential photosystem II (PSII) efficiency (Fv/Fm), with the former being a more accurate measure.[10]  High UV, salt, and heavy metal concentrations increased membrane dissolution and electrolyte leakage.[10]  X. aureola was more resistant to salt than other lichenized species Lobaria pulmonaria and Parmelia sulcata.[10]  Copper and zinc had no effect on Fv/Fm of X. aureola.[10]  It is likely that zinc and iodine in seawater protect Trebouxia and increase resistance to high salt and UV.[10]  Increasing environmental stress may exacerbate ROS formation and electrolyte leakage.  

References[edit]

  1. ^ a b c "Catalogue of Life : Xanthoria aureola (Ach.) Erichsen". www.catalogueoflife.org. Retrieved 2023-05-03.
  2. ^ a b c d e f g h i j k l m n Lindblom, Louise; Ekman, Stefan (2005). "Molecular evidence supports the distinction between Xanthoria parietina and X. aureola (Teloschistaceae, lichenized Ascomycota)". Mycological Research. 109 (2): 187–199. doi:10.1017/s0953756204001790. ISSN 0953-7562. PMID 15839102.
  3. ^ a b c d e f Fiorentino, Jennifer (2011). "The genus Xanthoria (Teloschistaceae, lichenised Ascomycota) in the Maltese Islands". The Central Mediterranean Naturalist. 5 (3–4): 9–17. S2CID 90539006.
  4. ^ a b c d Bednar, T. W.; Smith, D. C. (1966). "VI. Preliminary Studies of Photosynthesis and Carbohydrate Metabolism of the Lichen Xanthoria aureola". New Phytologist. 65 (2): 211–220. doi:10.1111/j.1469-8137.1966.tb06353.x. ISSN 0028-646X.
  5. ^ a b c d e Lindblom, Louise; Ekman, Stefan (2005). "Molecular evidence supports the distinction between Xanthoria parietina and X. aureola (Teloschistaceae, lichenized Ascomycota)". Mycological Research. 109 (2): 187–199. doi:10.1017/S0953756204001790. ISSN 0953-7562. PMID 15839102.
  6. ^ a b c Czeczuga, B. (1983). "Mutatoxanthin, the dominant carotenoid in lichens of the Xanthoria genus". Biochemical Systematics and Ecology. 11 (4): 329–331. doi:10.1016/0305-1978(83)90032-7. ISSN 0305-1978.
  7. ^ a b c Richardson, D. H. S.; Smith, D. C. (1968). "Lichen Physiology. X. The Isolated Algal and Fungal Symbionts of Xanthoria aureola". New Phytologist. 67 (1): 69–77. doi:10.1111/j.1469-8137.1968.tb05455.x. ISSN 0028-646X.
  8. ^ a b c Richardson, D. H. S. (1973), Ahmadjian, VERNON; Hale, MASON E. (eds.), "Photosynthesis and Carbohydrate Movement", The Lichens, Academic Press, pp. 249–288, doi:10.1016/b978-0-12-044950-7.50013-1, ISBN 978-0-12-044950-7, retrieved 2023-05-03
  9. ^ a b c d Kováčik, Jozef; Klejdus, Bořivoj; Štork, František; Malčovská, Silvia (2011). "Sensitivity of Xanthoria parietina to UV-A: Role of metabolic modulators". Journal of Photochemistry and Photobiology B: Biology. 103 (3): 243–250. doi:10.1016/j.jphotobiol.2011.04.002. ISSN 1011-1344. PMID 21531571.
  10. ^ a b c d e f Yemets, Olena; Gauslaa, Yngvar; Solhaug, Knut Asbjørn (2015). "Monitoring with lichens – Conductivity methods assess salt and heavy metal damage more efficiently than chlorophyll fluorescence". Ecological Indicators. 55: 59–64. doi:10.1016/j.ecolind.2015.03.015. ISSN 1470-160X.
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