Analysing fungal microbiome differences between the roots of healthy and diseased Chinese hickory (Carya cathayensis) trees.

Chinese hickory (Carya cathayensis), an important economic nut species in China, has recently suffered significant losses due to root rot. Previous 16S rRNA amplicon sequencing suggested that the bacterial dysbiosis may contribute to root rot, but the specific pathogens remained unclear. In this study, fungal community analysis revealed that Ascomycota and Basidiomycota dominated the rhizosphere soil, bulk soil, and root tissues, accounting for approximately 93.63% of total fungal communities. The relative abundance of Basidiomycota were more abundant in healthy root tissues, whereas the relative abundance of Ascomycota were enriched in diseased and dead roots. Interestingly, at the genus level, the dominant fungi Xylaria and Ilyonectria were detected exclusively in diseased and dead trees, while Condinaea and Gliocladiopsis were primarily found in dead trees. These genera have been previously reported as root rot pathogens in various plants, suggesting their association with C. cathayensis root rot. Notably, two biocontrol fungi, Chaetomium and Trichoderma, were also present in diseased and dead trees, highlighting potential strategies for disease management. Overall, this study identifies for the first time the potential pathogenic fungi responsible for C. cathayensis root rot and highlights candidate biocontrol agents, providing a foundation for future disease verification and control efforts.