Elevated temperatures facilitate extremely rapid zeaxanthin-dependent induction of nonradiative dissipation of excitation energy within photosystem II in Norway spruce needles

Vladimír Špundaa,b, Zuzana Materováa, Michal Štrocha,b, Kristýna Večeřováb, Jana Sestřenkováa, Iva Holubováa, Václav Karlickýa,b, Irena Kurasováa,b, Jan Semera, Otmar Urbanb
aFaculty of Science, University of Ostrava, 30. dubna 22, 701 03 Ostrava 1, Czech Republic; bGlobal Change Research Institute CAS, Bělidla 986/4a, 603 00 Brno, Czech Republic

Zeaxanthin (Z) accumulation, occurring after light (ΔpH) activation of the violaxanthin de-epoxidase (VDE) catalysing deepoxidation of violaxanthin (V) to Z via an antheraxanthin (A), contributes to mitigation of oxidative damage of the thylakoid membranes. Particularly, Z modulated ΔpH dependent non-radiative dissipation of excitation energy within photosystem II (NRD) is essential for photosystem II resistance against high light stress [1]. Especially, in Norway spruce acclimated to high-light a fast induction of maximal NRD and accumulation of Z was observed [2]. Recently, it has been shown that elevated temperatures can facilitate activation of VDE and accelerate V deepoxidation upon illumination [3].

In order to elucidate presumed interspecific variability of Z-dependent photoprotection at elevated temperatures, the dynamics of violaxanthin (V) de-epoxidation under different illumination regimes was studied together with chlorophyll a fluorescence transients (monitoring particularly the induction of NRD) in Norway spruce (Picea abies [L.] Karst.) seedlings, and Arabidopsis thaliana leaves (WT and L17 mutant over-expressing PsbS of pre-acclimated to temperatures ranging from 20 to 40°C.

Whereas in spruce seedlings the rapid phase of V deepoxidation (induced by either 10s illumination or 10 light-pulses of 1s duration at 1 min interval, 10x1s) was gradually stimulated upon increasing temperatures, in A. thaliana leaves considerable acceleration of V deepoxidation occurred just at 40°C. Moreover, only in spruce seedlings Z accumulation was induced by 1s light pulses at 32°C and higher temperatures, but neither in WT nor in L17 A. thaliana leaves. In agreement with these results, elevated temperatures stimulated formation of Z-dependent NRD induced by 1s light pulses only in spruce seedlings. Analysis of initial phase of V deepoxidation during illuminations shorter than 10s indicated a saturation of VDE capacity in spruce needles at elevated temperatures. These new findings about extremely rapid light-induced V deepoxidation and NRD induction observed in spruce seedlings at elevated temperatures are discussed with respect to specific fatty acid composition of spruce thylakoid membrane lipids and organization of photosystem II.

Acknowledgement

This work was supported by Grant Agency of the Czech Republic No. 13-28093S/P501.

References

[1] P. Jahns , A. R. Holzwarth, Biochim Biophys Acta 2012, 1817, 182–193.
[2] M. Štroch, K. Kuldová J. Kalina, V. Špunda, J Plant Physiol 2008, 165, 612-622.
[3] R. Zhang, D.M Kramer, J.A Cruz, K.R Struck, TD Sharkey, Photosynth Res 2011, 108, 171–181.