Ozone sensing and early signaling in plants: An outline from the cloud
Résumé
All along their life, plants and trees are exposed to various stresses, and particularly to abiotic ones. Ozone (O-3) is one of the most important air pollutants, whose ground levels keep increasing as a result of climate change. High O-3 concentrations deeply affect plants and cells, and impact worldwide crop and forest production. In plant leaves, O-3 directly interferes with surface tissues or reaches mesophyll cells through stomata. In this case, O-3 is almost immediately degraded into reactive oxygen species (ROS) in the apoplastic space of plant cells. For plants to acclimate to O-3, theO(3) stress signal has to be perceived at the cellular level and relayed to the nucleus to lead to cell reprogramming. The aim of this review is to focus on different O-3-sensing localizations, i.e., epicuticular waxes, the cell wall and the plasma membrane, and to detail the different early signaling components related to these sites - in particular lipids, membrane proteins (G proteins, NADPH oxidases and ion channels) and MAP kinases. Finally, some interesting putative membrane-related O-3 signaling components are presented as clues to be validated in future investigations.