Peroxisomes are highly dynamic, metabolically active organelles that used to be regarded as a sink for H2O2 generated in different organelles. However, peroxisomes are now considered to have a more complex function, containing different metabolic pathways, and they are an important source of reactive oxygen species (ROS), nitric oxide (NO) and reactive nitrogen species (RNS). Over-accumulation of ROS and RNS can give rise oxidative and nitrosative stress, but when produced at low concentrations they can act as signalling molecules.
Sandalio and Romero-Puertas review the metabolism of reactive oxygen and nitrogen species (ROS and RNS) in peroxisomes and their contribution to the regulation of plant development and acclimation to stress conditions. They highlight that peroxisomes can act not only as a sink of hydrogen peroxide, but also as sources of signalling molecules (ROS and RNS) and as a sensor for ROS/redox changes in the cell, thus triggering specific responses to environmental cues. They conclude that peroxisomes can therefore be regarded as a highly important decision-making platform in the cell where ROS and RNS play a determining role.
This article appears in the special issue ROS and NO Reactions in Plants.