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Bacillus strains act independently of immune system activation and compensate for its absence

ABSTRACT: The microbiota plays a crucial role in protecting plants from pests and pathogens. The protection provided by the microbiota constitutes not just the plant’s first line of defense, but possibly its most potent one, as experimental disruptions to the microbiota cause plants to succumb to otherwise asymptomatic infections. To understand how microbial plant defense is deployed, we applied a complex and tractable plant-soil-microbiome microcosm. This system, consisting of Arabidopsis plants and a 150-member bacterial synthetic community, provides a platform for the discovery of novel bacterial plant-beneficial traits, under a realistically complex microbial community context. To identify which components of the plant microbiota are critical for plant defense, we deconstructed this microcosm top-down, removing different microbial groups from the community to examine their protective effect on the plant when challenged with the leaf pathogen Pseudomonas syringae. This process of community deconstruction revealed a critical role for the genus Bacillus in protecting the plant from infection. Using plant RNA-seq and bacterial co-culturing experiments, we demonstrated that Bacillus-provided plant protection is independent of plant immune system activation. We also show that the level of plant protection is strongly dependent on the diversity of the protective inoculum. We show that deconstructing the microbiome top-down is a powerful tool for identifying and prioritizing microbial taxa with specific functions within it.

ORGANISM(S): Arabidopsis thaliana

PROVIDER: GSE285599 | GEO | 2025/01/01

REPOSITORIES: GEO

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Bacillus strains act independently of immune system activation and compensate for its absence

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