730 / 2019-05-10 06:15:50

New insights to N-hydroxy-pipecolic acid induced defense priming in angiosperms

systemic acquired resistance, long-distance signaling, defense metabolites

全体主题 > Biotic Stress

Signal propagation and coordination of whole-organism responses in plants rely heavily on small molecules. Systemic acquired resistance (SAR) is one such process in which long-distance signaling activates immune responses in uninfected tissue as a way to limit the spread of a primary, localized infection. Despite the importance of defense priming, the identity of the mobile defense signal that moves systemically throughout plants to initiate SAR has remained elusive. In this work, we report the discovery of N-hydroxy-pipecolic acid (NHP), a metabolite that plays a key role in initiating and amplifying SAR signaling in Arabidopsis. We show that Arabidopsis FMO1 (FLAVIN-DEPENDENT MONOOXYGENASE 1) synthesizes NHP from pipecolic acid and exogenously applied NHP moves systemically in Arabidopsis plants. We also provide evidence that genes associated with NHP production are conserved across angiosperm and demonstrate a role for NHP in mediating SAR responses in important crop plants. We used heterologous expression in Nicotiana benthamiana to identify a minimal set of genes required for NHP biosynthesis. Expression of these genes in tomato is sufficient to trigger SAR. Our results suggest chemical application or engineering strategies to induce NHP-mediated SAR are promising routes to improve broad-spectrum pathogen resistance in crops.