Population genetics reveals adaptive signatures of Exidia glandulosa across diverse climates from China

Abstract Background Wood-decaying fungus Exidia glandulosa , as the type species of the genus Exidia , is widely distributed in China. However, the scarcity of genomic limits the development of subsequent resources mining and utilization. Results Here, we firstly assembled the high-quality reference genome of E. glandulosa using third-generation and next-generation sequencing technologies, systematically analyzed the population structure and adaptive evolution characteristics of E. glandulosa across diverse climatic regions in China based on 78 samples. This assembled genome revealed an abnormally high level of genome heterozygosity, suggesting elevated ancestral genetic diversity or historical inter-lineage hybridization events. Population genetic analyses indicated that genetic differentiation among E. glandulosa populations, likely driven by regional climatic variations. Selection signal analysis suggested that temperate populations mainly responded to climate variations through enhancing signal transduction and stress responses, subtropical populations focused on energy metabolism, and plateau populations through multidirectional regulation of pathways including energy sensing, autophagy regulation, and DNA damage repair. Conclusions This study elucidates the significant roles of climatic and geographic factors in driving population differentiation and local adaptation in E. glandulosa . The rich genetic diversity and flexible molecular regulation mechanisms identified here underpin its wide ecological distribution. Additionally, this work provides a valuable genomic resource for future Exidia- related omics research and contributes to birding the gap in studies on climate adaptability of wood-decaying fungi within the framework population genetics.