Endolichenic fungi: the lesser known fungal associates of lichens

Abstract

Lichens are the result of a stable mutualism between a fungal and a photosynthesising partner (alga or cyanobacterium). In addition to the fungal partner in this mutualism, lichens are associated with endolichenic fungi which reside inside their thalli. The endolichenic fungi appear to have evolved with the lichen and many of them are a source of novel metabolites vested with unique bioactivities. There is very little information on the biology of endolichenic fungi and their interactions with the other components of a lichen microbiome. There is an urgent need to understand these aspects of endolichenic fungi such that their ecology and economic potential are known more completely. The current knowledge on endolichenic fungi is reviewed here.

Phylotypic Characterization of Mycobionts and Photobionts of Rock Tripe Lichen in East Antarctica

“…Lichens may have endolichenic or lichenicolous fungi, i.e., fungi present inside or on the surface of lichens, respectively. These fungi act as hidden potential producers of bioactive substances, such as detoxicants against anti-fungal substances from the lichen-forming fungi, antioxidants and lipase-/amylase-inhibitors, or necrotrophic/biotrophic parasites [4,5,6].…”

Cytotoxic Secondary Metabolites from the Endolichenic Fungus Hypoxylon fuscum

“…Recently, endolichenic fungi that inhabit the inner part of lichen without causing disease symptoms have been shown to be an attractive and valuable biological resource for the discovery of new bioactive natural products [2]. A number of secondary metabolites with diverse biological activities including antimicrobial, anti-inflammatory, and antiproliferative properties have been reported from endolichenic fungi [2][3][4]. However, in comparison with their tremendous species diversity, the number chemically investigated endolichenic fungi are limited.…”

Endolichenic fungal diversity associated with some lichens of the Western Ghats

“…The endolichenic fungi are nonobligate fungal component of lichen symbiome; they are similar to the endophytes of higher plants as they occur inside the lichen thallus, are nonpathogenic, and are transmitted horizontally [5][6][7]. Very few lichens across the globe have been screened for their endophytic fungal assemblages, and all of them invariably harbour these fungi [8]. These endolichenic fungi appear to produce many novel metabolites with technologically exploitable bioactivities [9][10][11][12].…”

“…Although India supports 2511 species of lichens [13], very few species have been screened for their endolichenic fungal assemblage, and that too mostly from temperate regions of Central Himalaya (Uttarakhand) [14]. Considering the paucity of information on endolichenic fungi [8] especially from India [15], we studied the endolichenic fungal assemblage in 10 lichen species (2 crustose, 4 each foliose and fruticose forms) occurring in the Western Ghats, southern India.…”