Journal Article

Protective role of the Arabidopsis leaf microbiota against a bacterial pathogen

Potthoff, Daniel B., Barandun, Niculò, Vogel, Christine M., Vorholt, Julia A., Schäfer, Martin

2021

Overview

The aerial parts of plants are host to taxonomically structured bacterial communities. Members of the core phyllosphere microbiota can protect Arabidopsis thaliana against foliar pathogens. However, whether plant protection is widespread and to what extent the modes of protection differ among phyllosphere microorganisms are not clear. Here, we present a systematic analysis of plant protection capabilities of the At -LSPHERE, which is a collection of >200 bacterial isolates from A. thaliana , against the bacterial pathogen Pseudomonas syringae pv. tomato DC3000. In total, 224 bacterial leaf isolates were individually assessed for plant protection in a gnotobiotic system. Protection against the pathogen varied, with ~10% of leaf microbiota strains providing full protection, ~10% showing intermediate levels of protection and the remaining ~80% not markedly reducing disease phenotypes upon infection. The most protective strains were distributed across different taxonomic groups. Synthetic community experiments revealed additive effects of strains but also that a single strain can confer full protection in a community context. We also identify different mechanisms that contribute to plant protection. Although pattern-triggered immunity coreceptor signalling is involved in protection by a subset of strains, other strains protected in the absence of functional plant immunity receptors BAK1 and BKK1. Using a comparative genomics approach combined with mutagenesis, we reveal that direct bacteria–pathogen interactions contribute to plant protection by Rhizobium Leaf202. This shows that a computational approach based on the data provided can be used to identify genes of the microbiota that are important for plant protection. Systematic analysis of bacterial phyllosphere isolates and their ability to protect Arabidopsis thaliana plants against infection, with the model pathogen Pseudomonas syringae pv. tomato DC3000, identified protective isolates such as Rhizobium Leaf202, whose activity involves direct interaction with the pathogen.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 631/326/2565/2134 / 631/449/2676 / 64 / Antibiosis / Arabidopsis - microbiology / Arabidopsis thaliana / Bacteria / Bacteria - classification / Bacteria - genetics / Bacteria - isolation & purification / Bacterial Physiological Phenomena / Biomedical and Life Sciences / Computer applications / Gnotobiotic / Host plants / Infectious Diseases / Leaves / Life Sciences / Medical Microbiology / Microbiology / Microbiota / Mutagenesis / Parasitology / Pathogens / Phenotypes / Phyllosphere / Phyllosphere microorganisms / Phylogeny / Plant bacterial diseases / Plant Diseases - microbiology / Plant Diseases - prevention & control / Plant immunity / Plant Leaves - microbiology / Plant protection / Pseudomonas syringae / Pseudomonas syringae - physiology / Rhizobium / Solanum lycopersicum - microbiology / Strains (organisms) / Virology