Speaker
Description
Beneficial root–microbe interactions enhance plant growth and stress resilience, including the establishment of a primed immune state known as Induced Systemic Resistance (ISR). Although ISR is typically assayed through leaf responses, its establishment begins in roots, where the cues that gate successful systemic protection remain poorly understood.
Iron (Fe) is a key element for ISR establishment and sits at the intersection of nutrition and immunity. As an essential cofactor for core metabolic processes, Fe is actively contested by hosts and microbes, and its limitation can itself activate components of the ISR transcriptional program.
Here, we asked how labile Fe pools and root barrier dynamics interact, from root microbial colonization to ISR competence. Using Trichoderma as a model beneficial fungus, we investigate the genetic regulation of Trichoderma-mediated ISR against foliar challenge in both Arabidopsis and tomato. We specifically focus on the convergence of ISR and Fe-dependent responses. During colonization, a dynamic remodeling of root apoplastic barriers is accompanied by redistribution of Fe pools across tissues, indicating coordinated changes in barrier state and Fe partitioning. Our results indicate that beneficial microbes reprogram root barrier properties and Fe homeostasis to create the spatial and chemical context necessary for systemic immune competence, linking nutritional immunity, cell wall dynamics, and microbe-mediated defense across species.