Misregulation of the jasmonate signaling pathway leads to altered plant microbiota interaction and plant stress responses

The model plant Arabidopsis thaliana hosts diverse microbial communities collectively known as the microbiota. The plant microbiota is generally taxonomically structured. Some of the members can promote plant fitness including growth and stress tolerance. However, microbial imbalance can also result in deleterious effects, a phenomenon known as dysbiosis that was first coined in the gut microbiome field. To unveil the regulatory mechanism to maintain plant homeostatic interaction with microbiota, we performed screening using defined synthetic bacterial communities. We identified an Arabidopsis mutant with altered microbial profiles, an overall increase of microbial load and microbiota-dependent growth defects. Transcriptomic and chemical complementation analyses confirmed that the aforementioned microbiota-dependent phenotypes are contributed by an upregulation of the jasmonate signaling pathway. Upregulation of the jasmonate pathway further promotes microbial growth, possibly forming a positive feedback loop. Even though activation of the jasmonate signaling pathway is known to enhance plant stress tolerance, hyperactivation of the pathway alters plant tolerance or resistance against multiple stressors. Plant association with the microbiota together with proper regulation of the jasmonate signaling pathway are thus essential to maintain plant response to environmental stressors.