The organic air pollutant cumene hydroperoxide interferes with NO antioxidant role in rehydrating lichen

MYRIAM CATALÁ, FRANCISCO GASULLA VIDAL, Pradas-del Real Francisco, García Breijo Francisco José, Reig Armiñana José, EVA BARRENO RODRÍGUEZ

2013

Environmental Pollution

Organic pollutants effects on lichens have not been addressed. Rehydration is critical for lichens, a burst of free radicals involving NO occurs. Repeated dehydrations with organic pollutants could increase oxidative damage. Our aim is to learn the effects of cumene hydroperoxide (CP) during lichen rehydration using Ramalina farinacea (L.) Ach., its photobiont Trebouxia spp. and Asterochloris erici. Confocal imaging shows intracellular ROS and NO production within myco and phycobionts, being the chloroplast the main source of free radicals. CP increases ROS, NO and lipid peroxidation and reduces chlorophyll autofluorescence, although photosynthesis remains unaffected. Concomitant NO inhibition provokes a generalized increase of ROS and a decrease in photosynthesis. Our results suggest that CP induces a ompensatory hormetic response in Ramalina farinacea that could reduce the lichen’s antioxidant resources after repeated desiccation-rehydration cycles. NO is important in the protection from CP.