An endogenous peptide PEP2 modulates Iron-deficiency signalling and root growth in Arabidopsis.

Iron (Fe) is an essential element for most of the living organisms including plants and humans, where plants serve as the primary source of our dietary iron intake. The availability of Fe determines plant fitness and yield. Thus, understanding of iron uptake, its acquisition and utilization is of critical importance to reap nutritional benefits from plant breeding. Despite significant progress in uncovering how iron homeostasis is regulated by transcription factors and phytohormones, molecular pathways that mediate Fe deficiency through the action of signalling peptides remain elusive. In this work, we reported the role of PROPEP2 (Plant Elicitor Peptide 2) and PEPR (Perception of Arabidopsis danger signal peptide receptor) in regulating plant growth and development under Fe-deprived conditions. We revealed that a Damage Associated Molecular Pattern (DAMP) such as PROPEP2 is significantly induced under Fe deficiency. We also show that PEP2 modulates the expression of Iron Regulated Transporter 1 (IRT1) and Ferric-Reduction Oxidase (FRO2) under Fe deficiency. Furthermore, we showed that PEPR2 perceives PEP2 to positively regulate reactive oxygen species (ROS) content and negatively regulate the primary root growth, iron content and rhizosphere acidification. Our findings reveal the complex interplay between Fe and DAMP signalling pathways in plants.