Rhizosphere Microbiome Transplantation as a Resource‐Efficient Approach to Enhance Growth and Microbial Functional Diversity in Urban Plants

Abstract

Urban soils are increasingly affected by degradation, compaction, pollution, and water limitation, which can constrain plant performance and the functioning of urban green spaces. Rhizosphere microbiome transplantation (RMT), which transfers entire microbial communities from donor plants to target species, has emerged as a potential alternative to conventional single‐strain inoculants. Here, we evaluated the effects of RMT on Cota tinctoria , a species commonly used in urban lawns and gardens, using microbial communities sourced from Festuca ovina . Following seedling establishment, plants were exposed to controlled drought conditions and assessed for growth (biomass, height, leaf number), physiological (chlorophyll content), biochemical (phenolic compounds), and microbial (community‐level physiological profiles of soil, rhizosphere, root endophytes, and leaf endophytes) responses. RMT was associated with higher plant biomass, height, and leaf production compared with the control treatment, whereas photosynthetic pigments and most phenolic compounds showed limited responses. Functional analyses revealed compartment‐specific patterns, with relatively stable soil and rhizosphere communities and pronounced increases in substrate utilization, metabolic activity, and functional diversity in root and leaf endophytes. Stress‐index analyses suggested a shift in endophytic carbon‐use patterns toward greater carbohydrate utilization. Collectively, these results indicate that application of a rhizosphere microbiome transplant is associated with changes in plant performance and microbial functional profiles under drought conditions. The study provides preliminary insights into the potential use of microbiome‐based approaches in urban vegetation management, while highlighting the need for additional mechanistic and field‐based investigations.