Freshwater offers a diversity of microhabitats for fungi to live in. Fungi have been isolated from a wide range of substrata from rivers and lakes; such as, foam, wood and leave. The research also included a study of the fungal colonization of selected woods submerged in rivers in Khao Yai National Park and the south of Thailand. The results revealed a wide diversity of species even on one type of forest and wood species in Thailand. Different timber species exposed in rivers supported very low percent overlap of the fungi found on each timbers and test sites. A single river may support more than 100 species of riverside trees, which presumably drop branches into the water. Attention has recently been given to the so-called “Ingoldian fungi” and in the last two years more than 100 species in this fungal group having been found. As a result, it is possible for such a river to be home to many thousands of wood- and leaf-decay fungi that await discovery.
Marasmius and Mycena are the most diverse genera of saprotrophic mushrooms known in the world, with over 1600 species described in Marasmius and over 1200 species described in Mycena. The greatest species diversity in these genera occurs in the tropics, although hundreds of taxa are found in temperate regions of both the southern and northern hemispheres. Nearly all species are saprotrophic, serving important ecological roles in litter decomposition, nutrient recycling and retention, pedogenesis, litter-binding with its concomitant inhibition of erosion, and as food sources for innumerable species of arthropods, mollusks and small vertebrates. A few species are parasitic of economically important food crops such as coffee, cocoa, sugar cane and on horticultural plants. In addition, a few species produce antibiotics; such as, strobilurin. Many species are host-specific or substrate-specific which accounts for some of the high diversity seen in tropical forests. Many tropical regions of the world (such as Southeast Asia, China, west central Africa and most of Indonesia) which undoubtedly support a great diversity of Marasmius, Mycena and allied genera have had only limited mycological exploration. This is especially true in Thailand. To help fill the void in our knowledge of these ecologically and medically important fungi, the objective of this project is to document the biodiversity, ecology and distribution of the genera Marasmius and Mycena in Thailand.
Polypores are fungi belonging to the family Polyporaceae. They are cosmopolitan recovering from the widest range of ecological niches, and possess saprobic mode of life (lignicolous or humicolous). They also show various utilization potential, such as being the medicinal products (e.g.: Ganoderma lucidum), foods (e.g.: Fistulina hepatica, Laetiporus sulphureus, and various Lentinus spp.), and bioremediation agents (e.g.: Pycnoporus sanquineous). Although Thailand is well known as source of high fungal diversity, polypores are poorly documented. A recent paper describing two new polyporous species in Thailand indicates that there are some polypores in the Thai forests waiting to be discovered. The intensive study on diversity and taxonomy of this fungal group is, therefore, required to complete the knowledge on biodiversity of the country, and to yield the culture for future research and utilization.
Diversity and molecular identification of endophytic fungi which produce antimicrobial substances
Endophytic fungi have been recognized as useful sources of bioactive secondary metabolites. They live asymptomatically within plant parts, intercellularly or intracellularly, for at least part of their life cycle. Endophytic fungi usually occur in aboveground plant tissues but are also found in roots. They have the ability to produce bioactive activity and antimicrobial substances against human pathogens. Various plants such as Garcinia species, mangrove plant and seagrasses were selected for fungal isolation and screened for their antimicrobial activity. Moreover, marine-derived fungi isolated from marine animals have been our target, as they may be a potentially source of novel and antimicrobial compounds. As many endophytes and marine-derived fungi are sterile when isolated onto agar media, therefore, molecular study and phylogenetic analysis based on ribosomal DNA sequence has become the most widely used tool for their identification to allow comparisons from high taxonomic levels down to the species levels. In connection with intensive searches for effective antimicrobial compounds, numbers of projects in collaboration with other institute and university have been made.
Fungi for industrial usages
An ideal industrial enzyme catalyst should possess the properties of high stability and activity over a wide range of conditions. Such enzymes are increasingly being sought from microorganisms existing in extreme environments. However, it is estimated that less than 5 % of all fungi has been recorded, and only ca. 0.7 % has been isolated. Further, even fewer extremophile fungi have been studied or isolated. Extremophiles are isolated from harsh environments such as hot springs (thermophiles), arctic sea-water (psychrophiles), deep-sea hydrothermal vents (barophiles), alkaline lakes (alkalophiles), hot sulphurous springs (acidophiles) and natural or artificial salt lakes (halophiles). Extremophiles are considered to be a novel source of extremozymes. Consequently, many extremozymes have not yet been discovered.
The positive economic impact of the common Aspergillus species; such as, A. niger, A. oryzae, undoubtedly supports the commonwealth of mankind. It probably leads us believe that there are limited Aspergillus species in this world, and the exploitation of these species is enough. In fact, these common Aspergillus account only 5.6% (ca 45 species) of the total described species. There are many more species, especially in the tropical forests, await the discovery and utilization.
Insect pathogenic fungi
Insect fungi are difficult to find and isolate, which explains why so few are available, no matter where in the globe they originate. However, the Clavicipitaceae (a family accounting for many of the insect pathogenic fungi) is a recognized ‘novel metabolite hotspot’. The recent recognition of this ‘hotspot’ feature, however, and a request for ‘fresh’ isolates has resulted in more than 1,000 isolations being made in the last few years. In this regard, the mycology research program plays a critical role in novel metabolite screening research in Thailand. There are now about 400 morphotaxa recognized in Thailand, of which approximately 30% are new species. The insect fungi have been isolated, and Thailand now has the richest collection of this group in the world, with 4,000-plus isolates representing 180-plus species deposited in the BIOTEC culture collection. This group of fungi has provided the most unique and potent biologically active compounds thus far investigated by BIOTEC scientists.
Tropical forests produce a large amount of litter yearly (in Thailand ranging from 4 to 11 tons/hectare/year, depending on forest types), which is a favored source of fungal colonization. Generally, litter composition are divided into leaf litter (60-70%), branch litter (12-15%), bark litter (1-14%), and fruit (also seed) litter (1-17%). Previous studies on fruit and leaf litter fungi revealed their high diversity with more than 200 known species collected, and 14 new species described. The result has shown the similarity of fungal species on the two litter types. However, the higher proportion of leaf litter than fruit litter on the forest floors supported the higher chance in encountering of the new species (12 new species from leaves while 2 new species from fruits). Further studies will focus on population dynamic during different stages of the decay, and fungi colonizing branch and bark litter. The overall studies may help us better understand the role of fungi in the decomposition process of tropical litter.
Marine fungi are worldwide ecological groups that are able to grow and sporulate exclusively in the marine habitats. They are distinct in their uniquely morphological features, in which serve as an aide to floatation, entrapment and attachment to substrata. Three lines of research are currently under investigation on the marine fungi of Thailand. Firstly, documentation of their diversity from new survey areas, the ecological interactions of higher marine fungi with other marine organism, such as seagrasses, seaweeds and corals, remain to be examined. Data gathered from this project will contribute state of knowledge on marine fungi in Thailand.
Higher marine fungi provide a potential source for novel bioactive compounds. More than 150 novel or new chemical structures have been reported from marine fungi. Secondly, therefore, sampling various substrata will be a challenging way to investigate their ability to produce new bioactive compounds. These fungi will be isolated into axenic culture so that they can be screened for novel metabolites. Marine ascomycetes have evolved from terrestrial ancestors, and that this has occurred several times. How these fungi invaded marine habitats, whether as pathogens, endophytes or saprophytes of wetland aquatic plants, remains unresolved. Moreover, we propose to examine the phylogenetic interrelationships of selected marine ascomycetes at different taxonomic levels, especially marine unitunicates and Dothideomycetes has been in progress.
An unusual habitat for fungi is the peat swamp forest in the southern province of Narathiwat, where species-colonizing senescent, decaying palms fronds are under investigation. Over 100 fungi have been recorded, of which many are new species, with at least one new genus. Differences have been noted between the fungal community colonizing submerged fronds and those in a dried environment, as still attached to the plant. Molecular studies of some palm fungi thought to be new genera or species have been undertaken.