Peroxisome-mitochondria contact-mediated ROS transfer: A key line of defence under plant stress

Reactive oxygen species (ROS) act as early messengers in plants exposed to drought, salinity, heat and other environmental challenges. Their timely removal is crucial. Unchecked ROS injure membranes, macromolecules and photosynthetic systems, ultimately curbing growth or causing cell death. While mitochondria possess in-house antioxidant machinery, how non-mitochondrial systems contribute to mitochondrial redox homeostasis has remained unresolved. Laura F. DiGiovanni et al. demonstrate that peroxisomes directly protect mitochondria through contact-mediated ROS shuttling. This discovery extends the concept of organelle crosstalk beyond metabolic exchange to contact-mediated ROS flux, adding a system-level buffer against oxidative stress. Deep understanding and regulation of this pathway are highly significant for exploring how ROS coordinate plant stress responses, enhancing crop stress resistance and reducing extreme environment-induced oxidative damage. This may provide breeders and agronomists with a novel approach to develop stress-resistant traits. • ACBD5-PTPIP51 interactions create dedicated, stable peroxisome–mitochondria (PO-Mito) membrane contact sites. • Oxidative stress increases PO-Mito contacts, shunting excess mitochondrial ROS into peroxisomes to maintain redox balance. • PO-Mito ROS transfer supports a coordinated multi-organelle antioxidant network that augments mitochondrial defenses.