EcoFAB 2.0 Root Microbiome Ring Trial SynCom17

A 17-member synthetic bacterial community (SynCom17) used in a standardized inter-laboratory ring trial across five international laboratories (LBNL, UNC Chapel Hill, Max Planck Cologne, Forschungszentrum Julich, U Melbourne) to study root microbiome recruitment and exudate composition of the model grass Brachypodium distachyon in EcoFAB 2.0 fabricated ecosystem devices. All 17 members were originally isolated from switchgrass rhizosphere soil and span four bacterial phyla (Actinomycetota, Bacillota, Bacteroidota, Pseudomonadota). In the full SynCom17, Paraburkholderia sp. OAS925 reproducibly dominates root colonization (~98% relative abundance) across all five labs, uniquely possessing a Type 3 Secretion System (T3SS), high motility, and acid resistance. Removing Paraburkholderia (SynCom16) yields a more variable community dominated by Rhodococcus sp. OAS809 (~68%), Mycobacterium sp. OAE908 (~14%), and Methylobacterium sp. OAE515 (~15%). The study demonstrated that EcoFAB 2.0 with standardized protocols achieves reproducible plant phenotype, exudate, and community structure data across continents, providing benchmark datasets for plant-microbiome research.