Photoinactivation of photosystem II: Is there more than one way to skin a cat?

Itzhak Ohad*, Alex Berg, Simon M. Berkowicz, Aaron Kaplan, Nir Keren

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

54 Scopus citations

Abstract

We briefly review the main mechanisms proposed for photodamage to photosystem II (PSII), at the donor and acceptor sides, and then discuss the mechanism whereby filamentous cyanobacteria inhabiting biological sand crusts such as Microcoleus sp. are able to avoid serious damage to their photosynthetic machinery. We show that the decline in fluorescence following exposure to excess light does not reflect a reduction in PSII activity but rather the activation of a non-radiative charge recombination in PSII. Furthermore, we show that the difference in the thermoluminescent peak temperature intensities in these organisms, in the presence and absence of inhibitors such as dichlorophenyl-dimethylurea (DCMU), is smaller than observed in model organisms suggesting that the redox gap between QA- and P680+ is smaller. On the basis of these data, we propose that this could enable an alternative, pheophytin-independent recombination, thereby minimizing the damaging 1O2 production associated with radiative recombination.

Original languageAmerican English
Pages (from-to)79-86
Number of pages8
JournalPhysiologia Plantarum
Volume142
Issue number1
DOIs
StatePublished - May 2011

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