The reactive oxygen species (ROS) signalling network is
highly conserved among aerobic organisms and controls a
broad range of biological processes such as growth, development,
and responses to biotic and/or abiotic stimuli (Mittler
et al., 2011). Although early research involving ROS metabolism
focused on the potential toxicity of ROS and the different
ROS-scavenging mechanisms, more recent studies
have focused on the role ROS play as signalling molecules.
To utilize ROS as signalling molecules, non-toxic levels must
be maintained in a delicate balancing act between ROS production,
involving ROS-producing enzymes and the unavoidable
production of ROS during basic cellular processes, and
the metabolic counter-process involving ROS-scavenging
pathways (Mittler et al., 2004).