Fig. 2

Pathogens employ multiple mechanisms to overcome plant iron-regulated immunity. a One strategy is to extract iron from host iron storage proteins. For example, under plant iron-depleted conditions, V. dahliae employs the Asp-type CFEM-containing VdSCPs (VdSCP33, VdSCP41, VdSCP43, VdSCP72, VdSCP99, VdSCP116, and VdSCP120) to sequester iron to counteract host resistance; under iron-depleted conditions or in planta, xfeA in Xanthomonas oryzae pv. oryzicola senses extra-cytoplasmic iron and changes the hydrogen bonding network of ligand channel domains by adenosine-to-inosine (A-to-I) RNA editing; C. graminicola utilizes the RIA pathway to efficiently acquire iron in the biotrophic stage, overcomes host low iron stress. b Pathogens secrete extracellular siderophores to chelate Fe³⁺ to limit host oxidative stress. Another strategy is to interfere with plant iron homeostasis. For example, effectors delivered by pathogens interact with and target the plant iron homeostasis protein to facilitate iron uptake or inhibit ROS production