Damage to the oxygen-evolving complex by superoxide anion, hydrogen peroxide, and hydroxyl radical in photoinhibition of photosystem II

Abstract

Under strong illumination of a photosystem II (PSII) membrane, endogenous superoxide anion, hydrogen peroxide, and hydroxyl radical were successively produced. These compounds then cooperatively resulted in a release of manganese from the oxygen-evolving complex (OEC) and an inhibition of oxygen evolution activity. The OEC inactivation was initiated by an acceptor-side generated superoxide anion, and hydrogen peroxide was most probably responsible for the transportation of reactive oxygen species (ROS) across the PSII membrane from the acceptor-side to the donor-side. Besides ROS being generated in the acceptor-side induced manganese loss; there may also be a ROS-independent manganese loss in the OEC of PSII. Both superoxide anion and hydroxyl radical located inside the PSII membrane were directly identified by a spin trapping-electron spin resonance (ESR) method in combination with a lipophilic spin trap, 5-(diethoxyphosphoryl)-5-phenethyl-1-pyrroline N-oxide (DEPPEPO). The endogenous hydrogen peroxide production was examined by oxidation of thiobenzamide.

Hydrogen sulfide counteracts chlorophyll loss in sweetpotato seedling leaves and alleviates oxidative damage against osmotic stress

“…Though H 2 O 2 acts as a signal for the activation of stress-response pathways (Bowler and Fluhr 2000;Knight and Knight 2001), the enhanced production of H 2 O 2 is damaging. Excessive H 2 O 2 can cause photo-oxidative damage of chlorophyll (Nield et al 2004;Song et al 2006), protein breakdown (Mehta et al 1992) and lipid peroxidation (Blokhina et al 2003). The overproduction of H 2 O 2 and MDA, a product of lipid peroxidation, were observed in leaves of sweetpotato seedling exposed to osmotic stress (Fig.…”

Differential gene expression is tied to photochemical efficiency reduction in virally infected Emiliania huxleyi

“…SOD plays an important role in the quenching of ROS at PSII and PSI (Song et al 2006, Krieger-Liszkay et al 2011). Therefore, lower sod2 expression coupled with lower PSII repair gene expression in infected E. huxleyi may result in enhanced O 2…”

Effects of high temperature coupled with high light on the balance between photooxidation and photoprotection in the sun-exposed peel of apple

“…This clearly indicates that there was an increased need for scavenging reactive oxygen species in the sunburned peel, and the upregulation of the downstream antioxidant system is a response to this increased production of reactive oxygen species. Indeed, both donor side and acceptor side of PSII photoinhibition have been demonstrated to increase the production of reactive oxygen species (Anderson et al 1998;Hakala et al 2005;Song et al 2006). Up-regulation of the antioxidant enzymes and metabolites has also been observed in the shaded peel of apple fruit upon sudden exposure to full sun ) and tomato fruit with sunscald (Torres et al 2006).…”