1. Contribution of Cyclic and Pseudo-cyclic Electron Transport to the Formation of Proton Motive Force in Chloroplasts 
Toshiharu Shikanai, Hiroshi Yamamoto 
Molecular Plant 
Volume 10, Issue 1, Pages (January 2017)
DOI: /j.molp
Copyright © 2017 The Author Terms and Conditions

2. Figure 1
Schematic Representation of Photosynthetic Electron Transport.
Linear electron transport (LET) from water to NADP+ is indicated by the green arrows. Two pathways of cyclic electron transport (CET) around PSI are indicated by the red arrows. The main CET pathway is mediated by the PGR5/PGRL1 complex, which interacts with PSI. On the other hand, the minor pathway depends on chloroplast NDH, which forms the supercomplex with PSI. The blue arrows indicate two pathways of pseudo-cyclic electron transport (pseudoCET). The authentic water–water cycle depends on O2 reduction around PSI. Resulting ROS is scavenged by superoxide dismutase (SOD) and ascorbate peroxidase (APX). Flv is conserved from cyanobacteria to gymnosperms but not in angiosperms. Flv mediates direct reduction of O2 to H2O. The electron donor in vivo is likely NAD(P)H or Fd. CET and pseudoCET are called alternative electron transport and contribute to pmf formation and consequently ATP synthesis without net accumulation of NADPH.
Molecular Plant  , 20-29DOI: ( /j.molp )
Copyright © 2017 The Author Terms and Conditions

3. Figure 2
Size and Components of pmf in Arabidopsis Plants Operating Different Alternative Electron Transport.
The pgr5 mutant is defective in the main pathway of PSI cyclic electron transport, leading to drastic reduction in the size of the pmf. The contribution of ΔpH was higher in the pgr5 mutant that that in the wild-type. The pgr5 mutant was transformed by the FlvA and FlvB genes originating from Physcomitrella patens (pgr5+35S; PpFlv no. 13). Although the size of the pmf was complemented to the wild-type level, the contribution of ΔpH was lower than that in the wild-type, leading to partial complementation of NPQ (Yamamoto et al., 2016). ECS signals were analyzed at different photon flux densities (PFD; μmol photons m−2 s−1). The error bars represent the SD with biological replicates (n = 5). This figure is a different presentation of the same data that was published previously (Yamamoto et al., 2016).
Molecular Plant  , 20-29DOI: ( /j.molp )
Copyright © 2017 The Author Terms and Conditions