Overexpression of the RieskeFeS Protein Increases Electron Transport Rates and Biomass Yield.

Andrew J Simkin,Christine A Raines,Lorna Mcausland,Tracy Lawson

doi:10.1104/pp.17.00622

Abstract

In this study, we generated transgenic Arabidopsis (Arabidopsis thaliana) plants overexpressing the Rieske FeS protein (PetC), a component of the cytochrome b6f (cyt b6f) complex. Increasing the levels of this protein resulted in concomitant increases in the levels of cyt f (PetA) and cyt b6 (PetB), core proteins of the cyt b6f complex. Interestingly, an increase in the levels of proteins in both the photosystem I (PSI) and PSII complexes also was seen in the Rieske FeS overexpression plants. Although the mechanisms leading to these changes remain to be identified, the transgenic plants presented here provide novel tools to explore this. Importantly, overexpression of the Rieske FeS protein resulted in substantial and significant impacts on the quantum efficiency of PSI and PSII, electron transport, biomass, and seed yield in Arabidopsis plants. These results demonstrate the potential for manipulating electron transport processes to increase crop productivity.

Highlights

In this study, we generated transgenic Arabidopsis (Arabidopsis thaliana) plants overexpressing the Rieske FeS protein (PetC), a component of the cytochrome b6f complex
We report on the production of Arabidopsis (Arabidopsis thaliana) with increased levels of the tobacco (Nicotiana tabacum) Rieske FeS protein, and we show that this manipulation resulted in increases in photosynthetic electron transport, CO2 assimilation, and yield
Transgenic Arabidopsis plants were selected on both kanamycin- and hygromycin-containing medium (Nakagawa et al, 2007), and plants expressing the integrated transgenes were identified using reverse transcriptase-PCR

Summary

Introduction

We generated transgenic Arabidopsis (Arabidopsis thaliana) plants overexpressing the Rieske FeS protein (PetC), a component of the cytochrome b6f (cyt b6f) complex. Questions have been raised about the feasibility of manipulating this multiprotein, membrane-located complex, given that it is composed of eight different subunits, six being encoded in the chloroplast genome (PetA [cyt f], PetB [cyt b6], PetD, PetG, PetL, and PetN) and two in the nucleus (PetC [Rieske FeS] and PetM; Willey and Gray, 1988; Anderson, 1992; Knight et al, 2002; Cramer and Zhang, 2006; Cramer et al, 2006; Baniulis et al, 2009; Schöttler et al, 2015) This protein complex functions as a dimer, with the transmembrane domains of both the Rieske FeS and cyt b6 proteins being implicated directly in the monomer-monomer interaction and stability of the complex and the petD gene product functioning as a scaffold (Hager et al, 1999; Cramer et al, 2006; Schwenkert et al, 2007; Hojka et al, 2014). This work provides evidence that the process of electron transport is a potential route for the improvement of plant productivity

Methods

Results

Discussion

Conclusion