Plant–soil compartments predominantly shape microbiome structure and function across juvenile and mature moso bamboo

Plant-associated microbes are essential for host resistance and productivity, but their host age-related dynamics remain poorly explored in long-lived species such as bamboo. In this study, we investigated the microbiomes of various bamboo compartments (i.e., bulk and rhizosphere soils, roots, stems, branches, and leaves) in juvenile and mature moso bamboo ( Phyllostachys edulis ), to explore age-dependent microbial patterns in various compartments. We found that (1) compartment type, rather than age, significantly influenced microbial alpha diversity, while both age and compartment significantly affected microbial community composition; (2) potential microbial migration was significantly greater among aboveground tissues than belowground ones, independent of plant age; and (3) associations among fungal functional groups varied by compartment and age, with the strongest effects observed in mature bamboo leaves, where endophytic fungi were negatively correlated with parasitic fungi, pathogenic fungi, and saprophytic fungi. These results highlight the predominant role of tissue compartment and the compartment-dependent effects of bamboo age in shaping the plant microbiome, providing insights into microbiome-associated processes relevant to bamboo forest health.