Diversity and bioactivity of endolichenic fungi in Usnea lichens of the Philippines.

Abstract

Endolichenic fungi (ELF; asymptomatic microorganisms living inside healthy lichen thalli) were isolated from three Usnea species, namely U. baileyi, U. bismolliuscula and U. pectinata, collected near the town of Sagada, Philippines. A total of 101 ELF were recovered representing 12 genera (classes Sordariomycetes and Eurotiomycetes), with the genera Nemania (50.5%, 51 isolates) and Xylaria (22.8%, 23 isolates) being the most abundant.Comparative analyses on the antimicrobial activities of lichens and ELF revealed that lichen crude extracts were effective against the Gram-positive bacterium Staphylococcus aureus and the yeast Candida albicans, while ELF crude extracts were effective against S. aureus, C. albicans and the Gram-negative bacterium Escherichia coli. The broad-spectrum nature of ELF has provided medicinal and industrial advantages over the slow-growing lichens as shown on their respective bioactivities. Extracts from ELF also had a higher total flavonoid content (TFC; 6.29-85.69 mg QE/g of extract) and stronger antioxidant activities (IC 50 : 0.57-19.63 mg/ml) than lichen-derived extracts. Although only culturable ELF were identified, this study provides the first evaluation of the diversity and bioactivities of culturable ELF from fruticose lichens of the genus Usnea in the Philippines.

In pursuit of promising microbes for drug discovery: tapping endolichenic fungi (ELF) from lichens

“…Galinato et al [35] recently reported that ELF could be leading producers of antioxidants within the lichen thalli, since ELF crude culture extracts exhibited stronger antioxidant activities than the crude lichen extracts. Similar results were reported by Santiago et al [36]. It is, thus, possible that ELF protects the host against harmful conditions through the production of reactive oxygen species (ROS).…”

“…Interestingly, in addition to the biopharmaceutical applications mentioned above, some of the ELF metabolites were also tested for their agricultural potential such as nematicidal [69], biocontrol [70], and phytotoxic activities [71,72]. In the Philippines, the first reports of ELF were that of Galinato et al [35], Santiago et al [36], and Tan et al [44]. Galinato and colleagues isolated 11 morphologically distinct ELF from the fruticose lichen, Ramalina peruviana, collected in Tagaytay City, Cavite Province.…”

“…Their ELF showed antioxidant activities, with three species reporting higher % RSA than the lichen host and the positive control, ascorbic acid [35]. On the other hand, Santiago et al [36] isolated ELF from another fruticose lichen, Usnea, specifically, from U. baileyi, U. bismolliuscula, and U. pectinata, all collected from Sagada, Mountain Province. Their studies also reported the antimicrobial and antioxidant activities of ELF, with many isolates exhibiting better activities than the lichen hosts.…”

Antioxidant compounds produced by endolichenic fungus Penicillium sp. induced from Pyxine subcinerea

“…Thom from Usnea baileyi and a Penicillium sp. from U. bismolliuscula (Santiago et al 2021). The mycelia of P. citrinum isolated from Parmotrema lichens have been shown to contain three antioxidant compounds, with two reported on and determined by Samanthi et al (2015) to be 5′-acetyl-3,5,7′-trimethoxy-3′H-spiro [cyclohexa [2,4]diene-1,1'-isobenzofuran]-3',6-dione and 4-acetyl-2'hydroxy-3',5',6-trimethoxy biphenyl-2-carboxylic acid, and the other reported on and determined by Wickramarachchi et al (2019) to be 10-ethylidene-2,4,9-trimethoxy-10,10a-dihydro-7,11-dioxa-benzo[b] heptalene-6,12-dione; sclerotioramine was not found in that fungal strain.…”

Influence of seagrass traits on the diversity of endophytic fungi

“…Endophytic fungi have been isolated from diverse hosts ranging from lichens (Santiago et al 2021), bryophytes (Zhou et al 2015), gymnosperms (De Mesa et al 2020), and angiosperms (Gautam et al 2013;Gautam 2014;General and Guerrero 2017). In the marine environment, endophytic fungi were found in every marine plant, e.g., mangroves (Apurillo et al 2019), algae (Sahoo et al 2021), and seagrasses (Supaphon et al 2017;Ettinger and Eisen 2020).…”