Speaker
Description
Iron is an essential micronutrient that supports core metabolic and defense processes in plants, yet its accumulation must be tightly controlled because excess iron promotes oxidative damage. In the rhizosphere, iron availability also profoundly influences plant–microbe interactions, creating a fundamental challenge for roots that must simultaneously acquire iron from the soil, maintain intracellular and organismal iron homeostasis, and restrict access to iron during immune responses. Understanding how plants coordinate these competing demands requires approaches capable of resolving iron dynamics across spatial and temporal scales. Our recent work has revealed multiple layers of regulation that coordinate iron homeostasis with immune signaling in roots. During sustained iron deficiency and microbial challenge, immune activation suppresses iron acquisition through spatial regulation of the iron deficiency signaling peptide IMA1, thereby limiting iron mobilization in the rhizosphere. In contrast, at much earlier timescales, perception of bacterial flagellin triggers rapid changes in intracellular iron availability that are coupled to receptor trafficking, membrane nano-clustering, and immune signaling of the receptorkinase SRF3. Together, these mechanisms enable roots to balance nutrient acquisition with defense while maintaining cellular iron homeostasis. These findings highlight both the importance and the difficulty of measuring highly dynamic metal distributions in living tissues. I will discuss our findings and emerging current bottlenecks in quantifying iron dynamics in plants and explore how emerging synchrotron- based approaches, including high resolution elemental mapping and chemical speciation analyses, could help elucidate the complex interactions of roots, iron and microbes.