Influence of tree mycorrhizal type, tree species identity, and diversity on forest root-associated mycobiomes

Abstract

Understanding the complex interactions between trees and fungi is crucial for forest ecosys- tem management, yet the influence of tree mycorrhizal types, species identity, and diversity on tree-tree interactions and their root-associated fungal communities remains poorly understood. Our study addresses this gap by investigating root-associated fungal communities of differ- ent arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) tree species pairs (TSPs) in a sub- tropical tree diversity experiment, spanning monospecific, two-species, and multi-species mixtures, utilizing Illumina sequencing of the ITS2 region. The study reveals that tree mycorrhizal type significantly impacts the alpha diversity of root-associated fungi in monospecific stands. Meanwhile, tree species identity’s influence is modulated by overall tree diversity. Tree-related variables and spatial distance emerged as major drivers of variations in fungal community composition. Notably, in multi-species mixtures, com- positional differences between root fungal communities of AM and EcM trees diminish, indicat- ing a convergence of fungal communities irrespective of mycorrhizal type. Interestingly, dual mycorrhizal fungal communities were observed in these multi-species mixtures. This research underscores the pivotal role of mycorrhizal partnerships and the interplay of bio- tic and abiotic factors in shaping root fungal communities, particularly in varied tree diversity settings, and its implications for effective forest management and biodiversity conservation.