Plant Identity Shapes Core Microbiomes on Green Roofs

ABSTRACT

Extensive green roof substrates support plant–microbe interactions that may contribute to ecosystem functioning. Yet the role of plant identity in shaping substrate‐associated microbiomes remains insufficiently resolved beyond Sedum ‐dominated systems. We examined bacterial and fungal communities associated with three plant species representing contrasting functional groups in sterilized and non‐sterilized green roof substrates, integrating taxonomic differentiation with plant functional traits and predicted metabolic pathways. Plant identity was associated with distinct microbial community patterns in sterilized and non‐sterilized substrates, and these associations varied with the substrate's initial microbial state. LEfSe identified 13 discriminant fungal genera in ITS data and 65 bacterial genera in V4 data; strong discriminant taxa included Mortierella, Schizothecium , and Serendipita in fungal communities, and Sphingomonas, Brevundimonas , and Tumebacillus in bacterial communities. Lotus corniculatus showed particularly distinct plant‐associated microbial patterns, while differences in predicted metabolic pathways provided a complementary functional perspective on taxonomic differentiation. Integrating plant functional traits with bacterial and fungal community analyses provided an ecological framework for interpreting plant‐associated microbiome differentiation in extensive green roof substrates. Integrating plant functional traits with microbial community analyses provides an ecological framework for interpreting plant‐associated microbiome differentiation in extensive green roof substrates.