Chlorella fusca CHK0059 Keystone-Taxa Antifungal SynCom

A three-member bacterial synthetic community assembled from the keystone taxa of the Chlorella fusca CHK0059 phytomicrobiome — Pseudomonas, Duganella and Brevibacterium — identified by microbiota structure and co-occurrence network analysis of plant hosts treated with the biofertilizer microalga. Applying Chlorella, a Chlorella methanol extract, or D-mannitol to the plant system shifted microbial distribution and diversity, with 2% D-mannitol markedly enriching Pseudomonas, implicating an algal-derived polyol as a recruitment signal in Chlorella-microbiome-plant communication. Recombined as a SynCom, the three keystone taxa suppressed the soilborne pathogen Fusarium oxysporum in both strawberry and tomato more strongly than any constituent strain alone — a community-level phenotype; the source reports "compared to individual strains" and does not report an additivity model, so no claim of synergy or superadditivity is made here. The record captures the SynCom as the mechanistic unit through which C. fusca CHK0059 exerts its disease-suppressive effect. A 2025 precursor study of the same strain (PMID:40064531) located the CHK0059-correlated keystone bacteria in the strawberry rhizosphere and named Pseudomonas, Duganella and Rhizomicrobium; the third genus differs from the Brevibacterium of the SynCom reported here, so the keystone set is not identical between the two studies.