A1 Refereed original research article in a scientific journal
Alternative electron transport mediated by flavodiiron proteins is operational in organisms from cyanobacteria up to gymnosperms
Authors: Petr Ilik, Andrej Pavlovic, Roman Kouril, Alessandro Alboresi, Tomas Morosinotto, Yagut Allahverdiyeva, Eva-Mari Aro, Hiroshi Yamamoto, Toshiharu Shikanai
Publisher: WILEY
Publication year: 2017
Journal: New Phytologist
Journal name in source: NEW PHYTOLOGIST
Journal acronym: NEW PHYTOL
Volume: 214
Issue: 3
First page : 967
Last page: 972
Number of pages: 6
ISSN: 0028-646X
eISSN: 1469-8137
DOI: https://doi.org/10.1111/nph.14536
Abstract
Photo-reduction of O-2 to water mediated by flavodiiron proteins (FDPs) represents a safety valve for the photosynthetic electron transport chain in fluctuating light. So far, the FDP-mediated O-2 photo-reduction has been evidenced only in cyanobacteria and the moss Physcomitrella; however, a recent phylogenetic analysis of transcriptomes of photosynthetic organisms has also revealed the presence of FDP genes in several nonflowering plant groups. What remains to be clarified is whether the FDP-dependent O-2 photo-reduction is actually operational in these organisms.We have established a simple method for the monitoring of FDP-mediated O-2 photoreduction, based on the measurement of redox kinetics of P700 (the electron donor of photosystem I) upon dark-to-light transition. The O-2 photo-reduction is manifested as a fast re-oxidation of P700. The validity of the method was verified by experiments with transgenic organisms, namely FDP knock-out mutants of Synechocystis and Physcomitrella and transgenic Arabidopsis plants expressing FDPs from Physcomitrella.We observed the fast P700 re-oxidation in representatives of all green plant groups excluding angiosperms.Our results provide strong evidence that the FDP-mediated O-2 photo-reduction is functional in all nonflowering green plant groups. This finding suggests a major change in the strategy of photosynthetic regulation during the evolution of angiosperms.
Photo-reduction of O-2 to water mediated by flavodiiron proteins (FDPs) represents a safety valve for the photosynthetic electron transport chain in fluctuating light. So far, the FDP-mediated O-2 photo-reduction has been evidenced only in cyanobacteria and the moss Physcomitrella; however, a recent phylogenetic analysis of transcriptomes of photosynthetic organisms has also revealed the presence of FDP genes in several nonflowering plant groups. What remains to be clarified is whether the FDP-dependent O-2 photo-reduction is actually operational in these organisms.We have established a simple method for the monitoring of FDP-mediated O-2 photoreduction, based on the measurement of redox kinetics of P700 (the electron donor of photosystem I) upon dark-to-light transition. The O-2 photo-reduction is manifested as a fast re-oxidation of P700. The validity of the method was verified by experiments with transgenic organisms, namely FDP knock-out mutants of Synechocystis and Physcomitrella and transgenic Arabidopsis plants expressing FDPs from Physcomitrella.We observed the fast P700 re-oxidation in representatives of all green plant groups excluding angiosperms.Our results provide strong evidence that the FDP-mediated O-2 photo-reduction is functional in all nonflowering green plant groups. This finding suggests a major change in the strategy of photosynthetic regulation during the evolution of angiosperms.
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