Plant responses to leaf bacteria

The perception of, and reaction to, biotic and abiotic stresses is critical for plant health. We recently identified a core set of genes consistently induced by members of the leaf microbiota, termed general non-self response (GNSR) genes. Here, we show that GNSR components conversely impact leaf microbiota composition. Specific strains that benefitted from this altered assembly triggered strong plant responses, suggesting that the GNSR is a dynamic system that modulates colonization levels of certain strains. Examination of the GNSR to live and inactivated bacteria revealed that bacterial abundance, cellular composition, and exposure time collectively determine the extent of the host response. We link the GNSR to pattern-triggered immunity (PTI), as diverse microbe- or danger-associated molecular patterns cause highly dynamic GNSR gene expression. Our findings suggest that the GNSR is the result of a fine-tuned perception and signaling system that feeds back to the leaf microbiota and contributes to the intricate balance of plant-microbiome interactions.