M.J. Mathushika . C.M. Nanayakkara . R.G.U. Jayalal . S. Thanthirige

Department of Plant Sciences, Faculty of Science, University of Colombo, Sri Lanka, Email: mathushikaj@gmail.com, Department of Plant Sciences, Faculty of Science, University of Colombo, Sri Lanka, Email: chandi@pts.cmb.ac.lk, Department of Natural Resources, Sabaragamuwa University of Sri Lanka, Email: rgujayalal@yahoo.com, Department of Chemistry, Faculty of Science, University of Colombo, Sri Lanka Email: sacheerangana.92@gmail.com

Received in final form on March 19, 2022

Abstract
Sri Lanka is well-known for its lichen biodiversity. Lichen is a symbiotic association between a fungal partner a photosynthetic partner. Lichen inhabiting fungi may reside in lichens without involving in symbiosis. Unique secondary metabolites, especially lichen inhabiting fungi are reputed for antimicrobial, anti-inflammatory, anti-proliferative and antioxidant activity. The lichen Heterodermia sp. was collected from the Paraviyangala mountain of Kalupahana mountain range in Belihuloya of Sabaragamuwa province in Sri Lanka. Lichen inhabiting fungi were isolated by plating surface sterilized thallus pieces onto potato dextrose agar medium. Emerging fungal tips from the plated pieces were transferred onto fresh medium to obtain pure cultures. Among the fungi isolated, Lasiodiplodia theobromae was identified using colony characteristics, micromorphology and DNA barcoding. The internal transcribed spacer (ITS) region was amplified using ITS-1 and ITS-4 primers to identify the fungus. Crude extracts were obtained from the fungal isolate via solvent extraction using three different solvents: Ethyl acetate, Hexane and Dichloromethane. Then they were screened in triplicate for antimicrobial activity by agar disk diffusion assay using bacteria: Escherichia coli (ATCC® 25922), Pseudomonas aeruginosa (ATCC® 27853) and Staphylococcus aureus (ATCC® 25923) and a clinical isolate of the fungus Candida albicans. Ethyl acetate and dichloromethane crude extracts showed antimicrobial activity against gram positive and negatives as well as Candida. The Ethyl acetate fraction gave the best results. Therefore Lasiodiplodia theobromae has the potential to be used as a source of novel antibacterial and antifungal compounds.

Keywords
Lichen, Symbiosis, Lichen inhabiting fungi, Secondary metabolites, DNA barcoding, ITS region, Antimicrobial activity.

Cite This Article
M.J. Mathushika . C.M. Nanayakkara . R.G.U. Jayalal . S. Thanthirige, The Anti-microbial Potential of Lasiodiplodia Theobromae Inhabiting the Lichen Heterodermia sp. Available in Sri Lanka, J. Innovation Sciences and Sustainable Technologies, 2(3)(2022), 129-136. https://doie.org/10.0725/JISST.2022653218

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