Strong pairwise interactions do not drive interactions in a plant leaf associated microbial community

Abstract

AbstractMicrobial communities that promote plant growth show promise in reducing the impacts of climate change on plant health and productivity. Understanding microbe-microbe interactions in a community context is paramount for designing effective microbial consortia that enhance plant resilience. In this study, we investigated the dynamics of a synthetic microbial community (SynCom) assembled fromArabidopsis thalianaleaves to elucidate factors shaping community composition and stability. We found notable disparities betweenin vitropairwise interactions and those inferred from correlation networksin planta. Our findings suggested that secondary metabolites, particularly antimicrobials, might mediate interactionsin vitro, but fade into the background in the community context. Through co-cultivation experiments, we identified the siderophore pseudobactin as a potent antimicrobial agent against several SynCom members, but its impact on community compositionin plantawas negligible. Notably, dominant SynCom members, such asPseudomonas koreensis, Flavobacterium pectinovorum, andSporobolomyces roseus, exhibited only positive correlations, suggesting synergism based on for example exopolysaccharides and biotransformation might drive community dynamics rather than competition. Two correlations between SynCom members in the co-abundance network corresponded with their pairwisein vitrointeractions, highlighting the potential for further research, and demonstrating the usefulness of correlation networks in identifying key microbe-microbe interactions. Our findings highlight the importance of considering microbiome-wide interaction studies and synthetic communities in understanding and manipulating plant microbiomes.