It would be prudent to screen fungi of less studied and extreme habitats [EH] to reduce the chances of rediscovering known bioactive compounds since such specialised habitats are abodes of many new species which are source of novel secondary metabolites [3]. It can be argued that with limited interaction webs owing to depauperate species richness in EH, antibiosis as a competitive mechanism may not be as diverse as in the species rich mesophilic environment. However, the unique species present in EH could house exceptional biosynthetic gene clusters for secondary metabolites. Since in fungi, expression of genes governing responses to external stress differ widely between species and adaptations to extreme environments involves horizontal gene transfers leading to major changes in adaptations, the chances of finding novel metabolites in EH fungi are relatively high [4].

Fungal endophytes are an example of stressing the need to explore fungi of less studied ecological groups. They survive as non-pathogenic endosymbionts in plants, seaweeds, and lichens. Certain endophytes including Colletotrichum, Xylaria, Trichoderma, Pestalotiopsis and Phomopsis have a wide  plant host range irrespective of the geographic or taxonomic connectivity of the plants [5]. Such endophytes may have a high diversity of secondary metabolites due to their interactions with diverse chemical milieu and different environmental conditions provided by different plant hosts and environments respectively. Indeed, endophytic Trichoderma species have greater metabolic potential attributable to their endophytic lifestyle when compared with the non-endophytic forms [6]. Genomes of endophytic Xylariaceae exhibit a large number of secondary metabolite gene clusters, gene duplications, and horizontal gene transfers and thus could be a good source of novel antibiotics. Fungi of other less studied habitats which need to be focused including lichenicolous, resinicolous, and endolithic fungi and those associated with marine sponges and corals, tropical peat, rumen, insect gut and exoskeleton, deep sea, and hypersaline environments.