The discovery of a new lichen species, *Allographa effusosoredica*, by Indian scientists has added to the rich biodiversity of the Western Ghats. This finding marks the complex symbiotic relationships within lichens and advances the understanding of their evolution and ecology. The research combines classical taxonomy with modern molecular techniques to reveal new vital information about lichen diversity and their algal partners.
Lichens and Their Symbiotic Nature
Lichens are composite organisms formed by a fungus and a photobiont, usually a green alga or cyanobacterium. The fungus provides structure and protection, while the photobiont captures sunlight to produce food through photosynthesis. This partnership allows lichens to survive in diverse and often harsh environments. They contribute to ecosystems by aiding soil formation, feeding insects, and serving as indicators of environmental health.
Discovery of Allographa effusosoredica
The newly identified species is a crustose lichen characterised by effuse soredia—powdery reproductive structures—and contains norstictic acid, a rare chemical in related species. It was found in the Western Ghats, a global biodiversity hotspot. This species is the 53rd of the genus *Allographa* reported in India and the 22nd from the Western Ghats, marking addition to India’s lichen catalogue.
Methodology – Integrative Taxonomy
Researchers used a polyphasic approach combining morphology, chemistry, and molecular biology. DNA sequencing of multiple genetic markers—mtSSU, LSU, RPB2 for the fungal partner and ITS for the algal symbiont—helped clarify the species’ identity. This approach set new molecular benchmarks for the genus in the region and confirmed its close relation to *Allographa xanthospora*.
Algal Partner and Evolutionary
The study identified the algal partner as a species of *Trentepohlia*, enhancing knowledge of photobiont diversity in tropical lichens. Morphologically, *A. effusosoredica* resembles *Graphis glaucescens*, raising questions about the boundaries between genera in the Graphidaceae family. This discovery supports the idea of locally adapted photobionts and complex evolutionary relationships within lichens.
Significance and Future Directions
This research is the first molecularly supported record of an *Allographa* species from India. It emphasises the need for more molecular studies on Indian lichens, especially in biodiversity-rich areas like the Western Ghats. About lichen diversity at the genetic level can improve conservation strategies and ecological knowledge of these symbiotic organisms.
Questions for UPSC:
- Critically analyse the role of symbiosis in the survival and ecological functions of lichens with suitable examples.
- What are the challenges and benefits of using molecular taxonomy in biodiversity studies? Explain with reference to Indian biodiversity hotspots.
- Comment on the significance of the Western Ghats as a biodiversity hotspot and its role in conservation biology.
- Explain the concept of bioindicators and discuss how lichens serve as bioindicators of environmental health and pollution.
