Symphony of Symbiosis

Abhismita Roy

Department of Botany

abhismita.roy@kalingauniversity.ac.in

In realms where fungi intertwine,

With algae bright and cyanobacteria fine,

Lichen emerge with utmost grace,

Harmony of life in a mutual embrace.

From fungal threads, a shelter spun,

In union strong, their bond begun,

Algae’s gift, carbohydrates won,

As fungi nurture beneath the sun.

Sugar alcohols flow, a sweet exchange,

Through hyphal embrace, they rearrange,

Glucose and ribitol, their currency range,

Fueling the union, a reciprocal change.

Cyanobacteria, a nitrogen  boon,

In tripartite harmony, under the moon,

Fixing the air, a shared fortune,

Expanding life’s tapestry, in lichen’s rune.

Sensitive to environment’s call,

Lichen whisper tales, silent yet tall,

Air pollution’s lament, they solemnly install,

A bioindicator’s noble hall.

Millennia pass, in lichen’s embrace,

Ages untold, in their secret place,

Surviving drought, in resilient grace,

On Earth’s surface, a silent chase.

In Martian sands, a test of might,

Lichens thrive in simulated light,

In space’s void, a cosmic flight,

A testament to life’s resilient plight.

In poetic verse, lichen’s tale unwinds,

A saga of symbiosis, where harmony binds,

In every thallus, a universe finds,

A lichen’s hymn, in nature’s minds.

Background

Lichens are composite organisms resulting from a mutually beneficial symbiotic relationship between fungi and algae or cyanobacteria. The fungi benefit from the carbohydrates produced by the algae or cyanobacteria through photosynthesis, while the latter are shielded from the environment and gain moisture and nutrients from the fungi [1]. This symbiotic association expands the ecological range of both partners. The fungal partner may lose the mitochondrial gene atp9, making it reliant on its symbionts. Algae produce sugars, including sugar alcohols like ribitol and sorbitol, absorbed by the fungus. Some lichens also associate with basidiomycete yeasts called Cyphobasidiales [2]. The association results in distinct morphology, physiology, and biochemistry compared to the individual components.

Lichens are found in diverse habitats globally, indicating successful symbiosis. They are sensitive environmental indicators, used for assessing pollution and metal contamination. Lichens exhibit intense antioxidant activity and slow growth rates. Some lichens are among the oldest living organisms, with lifespans spanning thousands of years [3]. They can survive extreme conditions, including dehydration and Martian simulations. Lichens have even been shown to survive unprotected in space, highlighting their resilience.

Lichens have various practical and cultural uses, spanning from food to biodegradation, traditional medicine, and aesthetics.

Food: Lichens are consumed by numerous cultures worldwide, serving as staple foods or delicacies. While some lichens are eaten primarily during famine, others are regularly incorporated into diets. However, obstacles such as indigestible polysaccharides and mildly toxic compounds must be addressed before consumption [4].

Lichenometry: This technique, introduced by Beschel in the 1950s, employs lichen growth rates to estimate the age of exposed rock surfaces [10]. It finds applications in archaeology, paleontology, and geomorphology, especially for dating surfaces less than 500 years old [5].

Biodegradation: Lichens possess the ability to degrade polyester resins and accumulate environmental pollutants like lead and copper. Certain species produce enzymes capable of degrading pathogenic forms of proteins, potentially aiding in environmental cleanup efforts [6].

Dyes: Lichens produce secondary compounds, including pigments used historically as dyes and primitive antibiotics. Litmus, a pH indicator, is derived from the lichen Roccella tinctoria, while traditional dyes for fabrics like Harris tweed were made from lichens such as Xanthoria parietina [7].

Traditional Medicine and Research: Historically, lichens were utilized in traditional medicine, with species like Lobaria pulmonaria being collected as “lungwort.” Modern research explores lichen metabolites for potential therapeutic or diagnostic applications, with compounds like usnic acid showing antibacterial properties [6,8].

Aesthetic Appeal: Lichens contribute to the visual landscape in various natural settings, from national parks to deserts and rocky seashores. Their intricate formations add to the ambiance of forests, while fruticose lichens are used in modeling hobbies for creating miniature trees and shrubs [9].

References

1. Chen, Jie; Blume, Hans-Peter; Beyer, Lothar (2000). “Weathering of rocks induced by lichen colonization – a review” (PDF). CATENA. 39 (2): 121. Bibcode:.39..121C. doi:10.1016/S0341-8162(99)00085-5. Archived (PDF) from the original on 2 April 2015. Retrieved 21 March 2015.
2. Jones, Clive G.; Shachak, Moshe (1990). “Fertilization of the desert soil by rock-eating snails”. Nature. 346 (6287): 839. Bibcode:346..839J. doi:10.1038/346839a0. S2CID 4311333.
3. Walker, T. R. (2007). “Lichens of the boreal forests of Labrador, Canada: A checklist”. Evansia. 24 (3): 85–90. doi:1639/0747-9859-24.3.85. S2CID 129100097.
4. Oksanen, I. (2006). “Ecological and biotechnological aspects of lichens”. Applied Microbiology and Biotechnology. 73 (4): 723–734. doi:1007/s00253-006-0611-3. PMID 17082931. S2CID 12172616.
5. Lawrey, James D. (1994). “Lichen Allelopathy: A Review”. In Inderjit; K. M. M. Dakshini; Frank A. Einhellig (eds.). Organisms, Processes, and Applications. ACS Symposium Series. Vol. 582. American Chemical Society. pp. 26–38. doi:10.1021/bk-1995-0582.ch002. ISBN 978-0-8412-3061-3.
6. Nash III, Thomas H. (2008). “Lichen sensitivity to air pollution”. In Nash III, T.H. (ed.). Lichen Biology (2nd ed.). Cambridge: Cambridge University Press. pp. 299–314. doi:1017/CBO9780511790478.016. ISBN 978-0-521-69216-8.
7. Knops, J.M.H.; Nash, T. H. III; Boucher, V.L.; Schlesinger, W.H. (1991). “Mineral cycling and epiphytic lichens: Implications at the ecosystem level”. Lichenologist. 23 (3): 309–321. doi:1017/S0024282991000452. S2CID 86133860.
8. Hogan, C. Michael (2010). “Abiotic factor”. Encyclopedia of Earth. Washington, D.C.: National Council for Science and the Environment. Archived from the original on 8 June 2013. Retrieved 27 October 2013.
9. Beltman IH, de Kok LJ, Kuiper PJC, van Hasselt PR (1980). “Fatty acid composition and chlorophyll content of epiphytic lichens and a possible relation to their sensitivity to air pollution”. Oikos. 35 (3): 321–326. Bibcode:.35..321B. doi:10.2307/3544647. JSTOR 3544647.
10. Innes, J. L. (1985). “Lichenometry”. Progress in Physical Geography. 9 (2): 187. Bibcode:…9..187I..