<i>Gliocladiopsis koreensis</i> sp. nov., <i>Ilyonectria koreensis</i> sp. nov., and <i>Mariannaea koreensis</i> sp. nov. (Nectriaceae), Novel Fungi Isolated from Soil in Jeju Island and Upo Wetland in the Republic of Korea

In this study, three novel fungal species belonging to the Nectriaceae family, <i>Gliocladiopsis koreensis</i> sp. nov., <i>Ilyonectria koreensis</i> sp. nov., and <i>Mariannaea koreensis</i> sp. nov., were discovered from soil samples collected at Iseung-ak Oreum on Jeju Island and the Upo Wetland in Changnyeong, Republic of Korea. They were confirmed as distinct species through molecular phylogenetic analyses using the ITS, <i>TUB</i>, <i>Tef1</i>, HIS3, and LSU sequences. Maximum-likelihood and Bayesian inference trees show that <i>G. koreensis</i> forms a sister clade with <i>G. curvata</i>, <i>G. singaporiensis</i>, and <i>G. peggii</i>, <i>I. koreensis</i> clusters closely with <i>I. qitaiheensis</i> and <i>I. changbaiensis</i>, and <i>M. koreensis</i> is phylogenetically related to <i>M. atlantica</i>, <i>M. fusiformis</i>, <i>M. elegans</i> var. <i>punicea</i>, and <i>M. terricola</i>. While all three new species exhibit unique morphological characteristics such as colony growth patterns, pigmentation, and microstructures that differentiate them from their closest relatives. The findings of these novel species contribute to the understanding of fungal diversity in these ecologically significant regions and highlight their potential applications in agriculture, nutrient cycling, and environmental restoration.