An Arabidopsis mutant with high operating efficiency of Photosystem II and low chlorophyll fluorescence

Bert J. van der Zaal,Niels van Tol,Paul J. J. Hooykaas,A. Alia,Martijn Rolloos,Huub J. de Groot,Dieuwertje Augustijn

doi:10.1038/s41598-017-03611-1

Bert J. van der Zaal, Niels van Tol + Show 5 more

Open Access

https://doi.org/10.1038/s41598-017-03611-1

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Journal: Scientific Reports	Publication Date: Jun 12, 2017
Citations: 7	License type: open-access

Affiliation: Leiden University

Abstract

The overall light energy to biomass conversion efficiency of plant photosynthesis is generally regarded as low. Forward genetic screens in Arabidopsis have yielded very few mutants with substantially enhanced photochemistry. Here, we report the isolation of a novel Arabidopsis mutant with a high operating efficiency of Photosystem II (φPSII) and low chlorophyll fluorescence from a library of lines harboring T-DNA constructs encoding artificial transcription factors. This mutant was named Low Chlorophyll Fluorescence 1 (LCF1). Only a single T-DNA insertion was detected in LCF1, which interrupted the expression of the full length mRNA of the gene At4g36280 (MORC2). We demonstrate that the high φPSII and low levels of chlorophyll fluorescence were due to a decrease in PSII:PSI ratio. Although LCF1 plants had decreased rosette surface area and biomass under normal growth conditions, they contained more starch per gram fresh weight. The growth defect of LCF1 was alleviated by low light and short day conditions, and growth could even be enhanced after a period of dark-induced senescence, showing that the plant can utilize its excess photosynthetic conversion capacity as a resource when needed.

Highlights

Photosynthesis is the process that harvests energy from sunlight and fixes it as chemical energy
In order to investigate whether genome interrogation can be used to generate novel plant lines with enhanced photosynthetic properties, a library of Arabidopsis plant lines harboring 3F-VP16 encoding T-DNA constructs was screened for significant changes in φPSII compared to the wild type Col-0 using chlorophyll fluorescence (CF) imaging
We transformed Col-0 plants with a 3F-VP16 encoding T-DNA construct which was reconstituted with the 3F encoding sequence identified in Low Chlorophyll Fluorescence 1 (LCF1), but these did not display high φPSII, demonstrating that the LCF1 phenotype was not triggered in trans by the 3F-VP16 fusion

Summary

Introduction

Photosynthesis is the process that harvests energy from sunlight and fixes it as chemical energy. CF imaging allows for the relatively easy quantification of the maximum quantum efficiency of PSII photochemistry (Fv/Fm) and of the operating light use efficiency of Photosystem II (φPSII)[8]. After first using Fv/Fm as a selection criterion, insertion mutants of the Arabidopsis gene HPE1 (At1g70200) were described which exhibited substantially higher φPSII than Col-011. We have used genome interrogation to investigate whether an innate capacity to perform more efficient photosynthesis can be artificially invoked in Arabidopsis by the large scale distortion of gene expression patterns. Introducing a single artificial gene in an otherwise wild type genome allows for the drastic perturbation of genome-wide gene expression patterns, and the potential induction of (novel) traits of interest

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