Dynamic Assembly and Multifunctional Roles of Plant Endophytic Microbiomes

Healthy host plants harbor taxonomically structured and diverse endophytic microbial communities that establish sophisticated symbiotic crosstalk with their hosts. These endophytic microbiomes confer multiple beneficial traits, including growth promotion, nutrient acquisition, and enhanced resistance to biotic and abiotic stresses, and are increasingly recognized as key modulators of plant fitness. The assembly of endophytic communities is not random but shaped by combined effects of environmental cues, host filtering, and microbial–microbial interactions, among which plant immunity constitutes an important host-selection dimension. Beneficial endophytes deploy diverse molecular tactics, such as masking microbe-associated molecular patterns (MAMPs) and secreting immune-suppressive compounds, to evade host PAMP-triggered immunity and effector-triggered immunity (PTI-ETI) surveillance for persistent internal colonization. In this review, based on the literature retrieved from Web of Science Core Collection and Scopus (2010–2026), we systematically summarize the colonization process, dynamic assembly rules, and driving factors of plant endophytic microbiomes. We further elaborate their multifaceted physiological functions in regulating plant growth, nutrient utilization, and stress adaptation. Deciphering such multilayered plant–endophyte interactions provides important insights for harnessing beneficial endophytes to advance sustainable agricultural development.