Organelle specific localisation of glutathione in Arabidopsis grown under different light intensities and spectra

Session

LSA.7 - Pathology, immunocytochemistry and biomolecular labelling

Authors

Dr Anna Gasperl (2), Dr Ákos Boldizsar (1), MSc Richard Pirklbauer (2), Mag Stefan Möstl (2), Dr Gábor Kocsy (1), Dr Gábor Galiba (1), Dr Maria Müller (2), Dr Günther Zellnig (2)

Affiliations

1. Agricultural Institute, Centre for Agricultural Research
2. Institute of Biology, University of Graz

Keywords

Arabidopsis thaliana L., glutathione, immunogold labeling, light quality, TEM 

Abstract text

Organelle specific localisation of glutathione in Arabidopsis grown under different light intensities and spectra 

 

Gasperl Anna¹, Boldizsar Ákos², Pirklbauer Richard¹, Möstl Stefan¹, Kocsy Gábor², Galiba Gábor²,  Müller Maria¹, Zellnig Günther¹

 

¹ Institute of Biology, University of Graz, NAWI Graz, Graz, Austria; ² Agricultural Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Hungary

 

In the present study the effects of different light spectra and light intensities related to glutathione metabolism were investigated on organelle level in Arabidopsis leaves.

Plant glutathione metabolism reacts upon oxidative stress [1]. Depending on the analysis method, levels of glutathione can be traced on different levels of organization (plant, organ, tissue). Immunocytochemistry and TEM imaging allow the quantification of metabolites such as glutathione on the subcellular level [2]. We have shown previously that subcellular ascorbate and glutathione levels are affected by high light stress in Arabidopsis [1]. The use of light emitting diodes (LEDs) gains increasing importance in growing indoor crops and ornamental plants. A combination of different LED types allows custom-made combinations of wavelengths and prevents damages related to high photon flux rates. However, scientific studies in relation to this general trend are scarce [3]. 

Arabidopsis thaliana L. plants (wildtype Col-0, ascorbate deficient mutant vtc2-1) were cultivated for two weeks in climate chambers under different light quality treatments (white 250 (NL) and 500 (HL) µmol m^-2 s^-1, far red 250 (RL) µmol m^-2 s^-1) under controlled conditions. Immunogold labeling of glutathione with computer supported transmission electron microscopy (TEM) was used to determine relative concentrations of glutathione in different cell organelles of Arabidopsis leaves. 

 

 Figure 1. Compartment specific means of gold particles bound to glutathione (± SE) per µm² in mesophyll cells of Arabidopsis (Col-0 black circles, vtc2-1 black triangles) after 14 days treatment with NL, HL and RL. n>60 for organelles. Significant differences between control treatment (NL) and the other treatments (HL, RL) were compared within the same line (Col-0, vtc2-1) via the Mann Whitney U-Test. Significance is indicated at the 0.01 (**) or 0.001 (***) level of confidence.

 

Light intensity had a more pronounced effect on subcellular glutathione concentration in Col-0, whereas vtc2-1 mainly responded to a change in light spectrum (Figure 1). Our results for Col-0 mitochondria and nuclei under LED high light treatment correspond to the results of a previous study, where high light likewise caused an increase in glutathione compared to control conditions [1]. The findings obtained in this study demonstrate that both light intensity and quality significantly affect glutathione metabolism thereby causing different reactions in the investigated Arabidopsis lines.

References

[1] E Heyneke, N Luschin-Ebengreuth et al, BMC Plant Biology 13 (2013),  p.104.

[2] B Zechmann and M Müller, Protoplasma 246 (2010), p.15.

[3] I Monostori et al, Frontiers in Plant Science 9 (2018), p.605.

[4] The authors gratefully acknowledge funding from the Magyar Tudományos Akademia (MTA), Hungary; Austrian FWF (I 2818-B25); Hungarian National Research, Development Innovation Office (grants ANN 117949, TéT_15-AT-1-2016-0048)