Systemic Photooxidative Stress Signalling

Systemic signalling of photooxidative stress from a high light (HL)-exposed leaf to a shaded leaf results in systemic acquired acclimation (SAA) in the distal tissue. As yet unanswered questions in systemic photooxidative stress signalling are in regard to what type of signal and what form of travel the signal takes from a small area of exposed tissue to as yet unstressed distal tissues. Issues such as the specificity of different stress responses, how different ROS signalling pathways converge, and antagonistically regulated systems are all currently being investigated. The majority of studies in this field, however, focus on the intercellular signalling aspects rather than leaf-to-leaf movement of the signal. Traditional studies of biotic long-distance signalling have not as yet been comprehensively applied to abiotic stress signalling research, particularly in regard to whether an abiotic signal is able to rapidly travel through the vasculature from leaf to leaf. This review covers literature relating to the effects that HL intensity and the production of ROS have on the stress signalling processes of light perception, retrograde and intercellular signalling, as well as leaf-to-leaf systemic signalling in the model organism Arabidopsis thaliana.