The rhizosphere microbiome of plants is essential for plant growth and health. Recent studies have shown that upon infection of leaves with a foliar pathogen, the composition of the root microbiome is altered and enriched with bacteria that in turn can systemically protect the plant against the foliar pathogen. This protective effect is extended to successive populations of plants that are grown on soil that was first conditioned by pathogen-infected plants, a phenomenon that was coined "the soil-borne legacy." Here we provide a detailed protocol for soil-borne legacy experiments with the model plant Arabidopsis thaliana after infection with the obligate biotrophic pathogen Hyaloperonospora arabidopsidis. This protocol can easily be extended to infection with other pathogens or even infestation with herbivorous insects and can function as a blueprint for soil-borne legacy experiments with crop species.
Keywords: Biotrophic pathogen; Disease resistance; Hyaloperonospora arabidopsidis (Hpa); Plant-microbiome interactions; Rhizosphere.