• The Plant Pathology Journal
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• v.40 no.5
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• pp.559-567
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• 2024

Continuous use of synthetic fungicides has led to explosive emergence of fungicide-resistant microbes. Therefore, there are urgent needs for environmentally friendly antimicrobial agents with novel modes of action. This study investigated endolichenic fungi (ELF) as a source of antimicrobial compounds against various plant pathogens. We utilized an One Strain MAny Compounds (OSMAC) approach to enhance the chemical diversity of fourteen ELF. This involved cultivation of ELF in four growth media and subsequently assessing antimicrobial activities of culture extracts. Nearly half of the culture extracts exhibited antimicrobial activity against a Gram-positive bacterium, but showed minimal activity against Gram-negative bacteria tested. Notably, culture extracts from two ELF, Chaetomium globosum and Nodulisporium sp., demonstrated significant inhibitory effects against plant pathogenic fungi. LC-MS/MS-based metabolome profiling confirmed the presence of known bioactive compounds like cyclic dipeptides and chaetoglobosins. These findings highlight the effectiveness of combining OSMAC and metabolomics for identifying antimicrobial agents for agricultural use.

• Mycobiology
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• v.50 no.1
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• pp.55-65
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• 2022

Lichen is a symbiotic mutualism of mycobiont and photobiont that harbors diverse organisms including endolichenic fungi (ELF). Despite the taxonomic and ecological significance of ELF, no comparative investigation of an ELF community involving isolation of a pure culture and high-throughput sequencing has been conducted. Thus, we analyzed the ELF community in Parmotrema tinctorum by culture and metabarcoding. Alpha diversity of the ELF community was notably greater in metabarcoding than in culture-based analysis. Taxonomic proportions of the ELF community estimated by metabarcoding and by culture analyses showed remarkable differences: Sordariomycetes was the most dominant fungal class in culture-based analysis, while Dothideomycetes was the most abundant in metabarcoding analysis. Thirty-seven operational taxonomic units (OTUs) were commonly observed by culture-and metabarcoding-based analyses but relative abundances differed: most of common OTUs were underrepresented in metabarcoding. The ELF community differed in lichen segments and thalli in metabarcoding analysis. Dissimilarity of ELF community intra lichen thallus increased with thallus segment distance; inter-thallus ELF community dissimilarity was significantly greater than intra-thallus ELF community dissimilarity. Finally, we tested how many fungal sequence reads would be needed to ELF diversity with relationship assays between numbers of lichen segments and saturation patterns of OTU richness and sample coverage. At least 6000 sequence reads per lichen thallus were sufficient for prediction of overall ELF community diversity and 50,000 reads per thallus were enough to observe rare taxa of ELF.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.97-101
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• 2011

To isolate a novel antifungal compound, we obtained 107 kinds of endolichenic fungi from Lichen Bioresources Center and examined their antifungal capability. Two fungi EL123 and EL156 showed high antifungal activity against Candida albicans in both MYA and EMM media. Nucleotide sequence analysis and NCBI Blast analysis in ITS region including 5.8S rRNA revealed that EL123 has 95% homology with Thielavia microspora and EL156, 99% with Cryptosporiopsis diversispora which belong to Ascomycetes. It observed that EL156 formed a branched mycelium whereas EL123 formed a straight one. EL156 also produced the antifungal substance faster than EL123 when they grew on MY liquid medium.

• Microbiology and Biotechnology Letters
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• v.40 no.1
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• pp.23-29
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• 2012

To isolate a novel antifungal compound, we obtained 100 kinds of endolichenic fungi from Korean Lichen & Allied Bioresources Center and examined their antifungal capability. Three fungi Usnea rigidula (2326), Parmotrema pseudotinctorum (2202) and Myelochroa sp. (2292) showed high antifungal activity against Candida albicans when they grew in both liquid and solid media. We extracted the culture supernatants of these three fungi with chloroform and then with ethyl acetate. Chloroform fraction exhibited the highest antifungal activities when those fractions were examined for the growth inhibition of Candida albicans with disc diffusion method. The chloroform faction was on further analysis with $C_{18}$ column chromatography to see whether the inhibitors are already known or not. Two peak fractions were collected from 4-day culture extract for Usnea rigidula and from 6-day culture extract for Parmotrema pseudotinctorum on the HPLC. A peak fraction from chloroform extracts of 4-day culture filtrate of Parmotrema pseudotinctorum showed higher antifungal activities against C. albicans and C. glabrata than another peak fraction. It appears that the antifungal materials are relatively nonpolar as usnic acid often found in lichenic fungi.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.165-171
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• 2013

To isolate a novel antifungal compound, we obtained 571 kinds of endolichenic fungi from Lichen Bioresources Center and examined their antifungal abilities. Four fungi Stereocaulon sp. (1429), Stereocaulon sp. (1430), Cryptosporiopsis sp. (0156), and Graphis sp. (1245) showed high antifungal activity against Candida albicans when they grew in both liquid and solid media. We extracted the culture supernatants of these fungi with chloroform and then ethyl acetate. The chloroform fraction exhibited the highest anti-fungal activities when those fractions were examined for the growth inhibition of Candida albicans with disc diffusion method. To see information for the inhibitor present in chloroform fraction we employed GC-MS for the fractions of Stereocaulon sp. (1429). We found that hexamethylcyclotrisiloxane, decanoic acid, hexadecanonic acid-methyl ester, 14-octadecenoic acid-methyl ester, and octadecenoic acid-methyl ester were present more in chloroform fraction than in ethylacetate fraction. This indicates that those compounds could be possible antifungal candidates since antifungal activity of chloroform extract was two times higher than that of ethyl acetate extract.

• Mycobiology
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• v.49 no.3
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• pp.294-296
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• 2021

An endolichenic fungus, Xylaria grammica strain EL000614, showed strong nematicidal effects against plant pathogenic nematode, Meloidogyne incognita by producing grammicin. We report genome assembly of X. grammica EL000614 comprised of 25 scaffolds with a total length of 54.73 Mb, N50 of 4.60 Mb, and 99.8% of BUSCO completeness. GC contents of this genome were 44.02%. Gene families associated with biosynthesis of secondary metabolites or regulatory proteins were identified out of 13,730 gene models predicted.