Isolation and Identification of Fungi Associated with Decay of Quercus mongolica

Abstract

The Quercus mongolica has a high utilization value in industrial economic sector. The species is distributed throughout Korea, however, the damage caused by deterioration such as discoloration and decay is severe. For this reason, the deterioration of Q. mongolica is an obstacle to its use as wood, but research on deterioration factors is insufficient. In this study, we focused on fungi as a factor influencing the deterioration of Q. mongolica, and isolated and identified the fungi from the deteriorated Q. mongolica. In additions, in order to confirm whether the identified fungi actually affects wood deterioration, enzyme activities of the identified fungi were evaluated and related mass loss of wood treated with the fungi was measured by wood decay test. As a result of sequencing analysis using the ITS region of the genomic DNA of the fungi isolated from Q. mongolica, Mucor circinelloides, Cunninghamella elegans, and Umbelopsis isabellina 3 species belonging to Mucoromycota phylum, and Ophiostoma piceae and Aureobasidium melanogenum 2 species belonging to Ascomycota phylum were identified. These five fungi had enzyme (i.e. cellulase, laccase) activities related to wood decay and reduced the mass of heartwood and sapwood of Q. mongolica in practice. In particular, O. piceae and A. melanogenum, which have both cellulase and laccase activities, showed 6.9% and 1.5% mass loss, respectively. These results indicated that five fungi identified in this study influence the deterioration of Q. mongolica and are wood decaying fungi for Q. mongolica potentially.

Environmental Suitability for Conservation and the Risk Period for Fungal Damage of Wooden Cultural Heritages in Korea

“…Among them, temperature (T) and relative humidity (RH) are highly related to meteorological conditions, greatly affecting the germination and growth of various airborne fungi inside and outside WCHs. In particular, in the Korean Peninsula with four distinct seasons, when high internal T and RH conditions are created in summer, and simultaneously the air quality inside the space is stagnant, the germination and growth of rot fungi and imperfect fungi, which gain nutrition from organic cultural heritages, cause biological damage to the materials of the heritage structures (Ham et al, 2021;Hong et al, 2018Hong et al, , 2019Lee et al, 2022;Nandika et al, 2023;Priadi et al, 2021Priadi et al, , 2023Yun et al, 2021). For example, in the 1990s, Seosagan-Jang, one of the storage places for Tripitaka in Haeinsa Temple, had poor ventilation, causing high RH during the rainy season every year and continuous mildew growth on the surface of several printing wood blocks stored inside (Park, 2011).…”