# Root Fungal Endophyte Communities Differ Among Plant Functional Groups in an Alpine Meadow

## TL;DR

This study shows that different plant groups in alpine meadows host unique fungal communities in their roots, influenced by traits like nitrogen levels and root depth.

## Contribution

The study reveals that monocot and dicot forbs host distinct fungal communities, challenging traditional plant classifications and emphasizing microbial roles in alpine ecosystems.

## Key findings

- Monocot and dicot forbs host significantly different root fungal endophyte communities.
- Legumes have more symbiotic fungal types compared to grasses.
- Root nitrogen concentration is the strongest factor shaping fungal endophyte communities.

## Abstract

Root fungal endophytes (RFEs), which live inside plant roots without causing disease, are known to differ among plant species, but it is unclear whether they also vary among broader plant functional groups (PFGs), such as grasses, legumes, and forbs. In an alpine meadow study of 45 plant species across four PFGs (grasses, legumes, dicot forbs, and monocot forbs), we found that each group hosted distinct RFE communities. Notably, monocot and dicot forbs, which often grouped together in traditional classifications, harbored significantly different fungal communities, suggesting they should be treated separately. Legumes had more symbiotic fungal types compared to grasses. Roots’ nitrogen concentration was the strongest factor shaping RFE communities, followed by root depth, biomass, and how common a plant species was. These findings show that plant functional traits and abundance shape belowground microbial partnerships, highlighting the need to include microbes when studying plant diversity and ecosystem resilience in fragile alpine environments.

Disparities in root fungal endophyte (RFE) communities are well documented among plant species, yet differences among plant functional groups (PFGs) remain unclear. Given that RFE community structure is influenced by host plant abundance and species-specific root functional traits, and that PFGs exhibit divergent relative abundances and root traits, we hypothesize that PFGs harbor unique RFE communities, potentially aligned with their functional traits. We investigated RFE communities in 45 alpine meadow species representing four PFGs (grasses, legumes, dicot forbs, and monocot forbs), using high-throughput sequencing. Ascomycota dominated all groups (>50%) except monocot forbs (38.9%). Distinct differences in the RFE community species composition were found among PFGs. In particular, the differences were significant between dicot forbs and monocot forbs, and between monocot forbs and grasses, which contradicted with conventional PFG classification that combined monocot and dicot forbs as a single PFG. Moreover, marker operational taxonomic units (OTUs) with symbiotic lifestyles were more abundant in legumes, and their functional composition differed significantly from grasses. Roots’ nitrogen concentration was the strongest predictor of RFE variation, followed by root length, biomass, and species abundance. These results emphasize the importance of integrating microbial partners into understanding plants’ functional diversity and ecosystem resilience in alpine environments.