Data from: Chemical structure predicts the effect of plant-derived low-molecular weight compounds on soil microbiome structure and pathogen suppression

1. Plant-derived low molecular weight compounds play a crucial role in
shaping soil microbiome functionality. While various compounds have been
demonstrated to affect soil microbes, most data are case-specific and do
not provide generalizable predictions on their effects. Here we show that
the chemical structural affiliation of low molecular weight compounds
typically secreted by plant roots – sugars, amino acids, organic acids and
phenolic acids – can predictably affect microbiome diversity, composition
and functioning in terms of plant disease suppression. 2. We amended soil
with single or mixtures of representative compounds, mimicking carbon
deposition by plants. We then assessed how different classes of compounds,
or their combinations, affected microbiome composition and the protection
of tomato plants from the soil-borne Ralstonia solanacearum bacterial
pathogen. 3. We found that chemical class predicted well the changes in
microbiome composition and diversity. Organic and amino acids generally
decreased the microbiome diversity compared to sugars and phenolic acids.
These changes were also linked to disease incidence, with amino acids and
nitrogen-containing compound mixtures inducing more severe disease
symptoms connected with a reduction in bacterial community diversity. 4.
Together, our results demonstrate that low molecular weight compounds can
predictably steer rhizosphere microbiome functioning providing guidelines
to engineer microbiomes based on root exudation patterns by specific plant
cultivars or crop regimes.