Iron is essential for metabolic processes in most living organisms. Pathogens and their hosts often compete
for the acquisition of this nutrient. However, iron can catalyze the formation of deleterious reactive oxygen
species. Hosts may use iron to increase local oxidative stress in defense responses against pathogens.
Due to this duality, iron plays a complex role in plant-pathogen interactions. Plant defenses against
pathogens and plant response to iron deficiency share several features, such as secretion of phenolic
compounds, and use common hormone signaling pathways. Moreover, fine tuning of iron localization
during infection involves genes coding iron transport and iron storage proteins, which have been shown
to contribute to immunity. The influence of the plant iron status on the outcome of a given pathogen
attack is strongly dependent on the nature of the pathogen infection strategy and on the host species.
Microbial siderophores emerged as important factors as they have the ability to trigger plant defense
responses. Depending on the plant species, siderophore perception can be mediated by their strong iron
scavenging capacity or possibly via specific recognition as pathogen associated molecular patterns. This
review highlights that iron has a key role in several plant-pathogen interactions by modulating immunity.