What is fungal biodiversity to us?
By
D. Jayarama Bhat
Department of Botany, Goa University, Goa-403 206
Fungi are eukaryotic, achlorophylous, filamentous or unicellular, microorganisms. They are ubiquitous in nature, found everywhere, and constitute a major decomposers’ community in the biosphere. By number, they are very large. Of the estimated 1.5 million species, only about 83,000 have so far been documented from around the world. Then, where are the remaining fungi? Nearly 30% of the known fungi have been recorded only from the tropics. Fungi of India are known, to some extent. The unexplored habitats in the warmer belt of the globe including the Indian subcontinent are said to be the ‘store-house’ of hitherto unknown fungi in nature.
By virtue of their amazingly large number and diversity of enzymes and metabolites, fungi are able to subsist either as saprotrophs, obligate pathogens or facultative inhabitants, on plants and animals. The substrates and/or habitats that fungi occupy include aerial leaves, internal tissues of plants, decaying leaves and twigs, herbivore dung, live or dead insects, ponds, lakes, streams and rivers, mangroves, oceans and seas and humans . Conspicuous fruit-body forming mushrooms, polypores, brackets, earth-stars, bird-nests, etc., belonging to Basidiomycota and morels and some of the big cup-fungi in Ascomycota are referred as macrofungi. All other fungi, viz. members of Chytridiomycota, Zygomycota and Ascomycota and their asexual phases, are considered as microfungi.
The factual species diversity of fungi may be much greater than the estimated numbers. Estimates of the global species vary from 0.5 to 9.9 x 106 with a proposed 1.5 x 106 species. It is possible that as many as 1.5 M species have still remained undetected.
Diversity of fungi exhibited in form and structure is often expressed in function. The taxonomic diversity in fungi is said to be a reflection of their metabolic versatility. In the recent years, a large number of molecules with known and unknown biological activity have been discovered from fungi. Presently, the fungi are considered as most valuable and economically stainable resources that could conveniently be channelized into various applications in agriculture, bioremediation, carbon sequestration, energy production, fermentation, feed, food, fuel, health-care and industry.
Biodiversity studies
Recent years have witnessed keen interest in understanding the importance of various ecosystems and their biodiversity. The interest is reflected through programmes such as the ‘Global Taxonomy Initiative’, endorsed by the Convention on Biological Diversity (CBD), which is aimed to improve taxonomic knowledge and capacity building and to promote conservation, sustainable use and equitable sharing of the benefits of biodiversity. As per the guidelines of CBD, National Biodiversity Authority (NBA), India, has been set up and is presently functioning from Chennai (www.nbaindia.org).
Strangely, fungi attracted less attention in discussions of biodiversity studies and conservation efforts, as compared to plants and animals. Floristic mycology did not attain significance in the biological scene. Nevertheless, continued survey and isolation and documentation by several dedicated mycologists from a few universities and institutions have resulted with accumulation of recognizable data on fungi of India.
India, endowed with diverse physiography, vegetation, ecosystem and habitats, has huge potential for further explorations and utilization of its untapped biodiversity. The NBA has recently formulated guidelines for understanding and utilization of the microbial diversity, including fungi, of our country. A variety of habitats and substrates present in two mega-biodiversity zones, i.e. the Western Ghats in southern India and the north-eastern Himalayas, are rich repositories of fungal wealth. Efforts are now on to document the fungi of India from hitherto unexplored and under-explored habitats and substrates and to assess the economic value of these microorganisms. The ‘All-India Coordinated Project on Taxonomy (AICOPTAX) of Fungi’, initiated by the Ministry of Environment and Forests, Government of India, since 2000, is one such major attempt.
Fungi of the Western Ghats
Though fungi of the Western Ghats have been explored and documented since the beginning of last century, only small fraction of them is known so far. We have been exploring the fungal diversity in this laboratory, since the inception of the University. It will be a challenge for the future not only to unravel the fungal wealth of this region and conserve in ex situ repositories but also to use them for advantage in sectors such as agriculture, bioremediation, C-sequestration, energy, fermentation, feed, food, fuel, and health-care.
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Uses of fungi
Fungi are used in bread-making, edible mushrooms, alcoholic fermentations, production of life-saving drugs, non-toxic dyes and flavours, biocontrol agents of crops and human pathogens, nutritive and protein-rich food additives, acids and enzymes useful in bio-pulping, bioleaching and bioremediation, mycorrhizal biofertilizers, and SSF of organic waste. Annual global trade of goods and services from fungi in the form of acids, antibiotics, beverages, biofertilizer, biofuel, bioremediation, foodstuffs, healthcare, immunosuppressant, industrial enzymes, vitamins and waste degradation, is said to be about US $ 43 million in 2004. The search for industrially useful novel metabolites and medicinally significant bioactive molecules, is now a priority area research. However, less than 1% of fungal species are available in live form in culture collections around the world, and only a small fraction of the fungal taxa has so far been assessed for their activity.
Efforts are now on to document and conserve the fungi of India from hitherto unexplored and under-explored habitats and substrates and further to assess the economic value of fungal biodiversity. With vast stretches of forests, numerous seasonal streams and rivulets, the forests of Western Ghats have an invaluable wealth of fungal diversity to showcase in the coming days.
We can transform the fungal resources into sustainable revenue generating national wealth. We need very dynamic, motivated and talented young people to work with fungi. The institutes of higher learning in the country should train more young mycologists who would translate the biological wealth into sustainable national treasure. Let the media tell around the world around that facilities are available at Goa University to study the fungi and understand them.
