Nitrogen addition affects tree trait expression by altering endophytic microbe diversity

Previous studies have demonstrated that plant-associated microbial diversity can confer fitness advantages to the plant host and influence ecosystem functions. The extent to which plant-associated microbial diversity modulates the response of plant fitness to environmental changes through its role in defining trait expression in the host plant remains, however, largely unknown.

In this study, we aimed to address this gap by sampling plant traits and endophytic microbial communities at seven experimental sites simulating nitrogen deposition, a significant environmental change factor.

We found a robust correlation between leaf and root traits, and the correlation remains unaffected by nitrogen addition, indicating a coordinated response of plants across both aboveground and belowground organs in the face of environmental changes. Furthermore, our evidence suggests that the adaptation of plant trait expression to nitrogen deposition is specifically modulated by the diversity of plant endophytic fungi and bacteria, rather than endophytic microbial community structure.

Our results highlight the crucial role of endophytic microbe diversity in modulating plant host adaptation to environmental changes. These findings emphasize the importance of understanding the interactions between plants and their endophytic microbiome to better predict the impacts of environmental changes on ecosystem functions.