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Genetic and genomic studies of the Korean oak wilt fungus (Raffaelea quercus-mongolicae) provide information of its biology and ecology

Mee-Sook Kim: Dept. of Forestry, Environment and Systems, Kookmin University

<div><em>Raffaelea quercus-mongolicae</em> is associated with oak wilt disease in South Korea, and this ambrosia beetle-vectored fungus has thus far only been found in South Korea. Mongolian oak (<em>Quercus mongolica</em>) is the primary host of <em>R</em>. <em>quercus-mongolicae</em>, and it is widely distributed over central South Korea where it is ecologically important in native forests. The objectives of this study on <em>R</em>. <em>quercus-mongolicae</em> were to assess genetic diversity and population structure using Restriction-site-Associated-DNA sequencing (RAD-seq), sequence the whole genome, and analyze the transcriptome under <em>in</em> <em>vitro</em> conditions. Results of RAD-seq indicated low genetic diversity and no apparent population structure among South Korean populations of <em>R</em>. <em>quercus-mongolicae</em>, which supports the hypothesis that this fungus was introduced to South Korea. The genomic sequence of <em>R. quercus-mongolicae</em> (KACC44405; 27-Mb), along with other <em>Raffaelea</em> spp., will provide valuable resources for comparative genomic analyses and identifying genes that contribute to potential pathogenic relationships between the fungus and host, and potential symbiotic relationships between the fungus and insect vector. Transcriptomic analyses showed that many gene products were predicted to have diverse functions, such as ATP production for growth, recovery under stressed conditions, fluidity of cell membrane, maintenance of cell membrane, and regulation of fungal virulence.</div>