Plants modulate their defence signalling networks in response to various biotic stresses via inter-organ communication. Song et al. evaluate the root-mediated transmission of systemic acquired resistance (SAR) in response to soil-borne and air-borne plant pathogens.

The SAR-triggering chemical benzothiadiazole (BTH) induces a SAR signal which is transmitted through the root-to-root system from SAR-induced plants to neighbouring plants subjected to local chemical and pathogenic bacteria. Salicylic acid (SA) is shown to be a major signal molecule in this SAR transmission through the root system.
This paper is part of the Root Biology Special Issue.