Comparison of State Transitions of the Photosynthetic Antennae in Arabidopsis and Barley Plants upon Illumination with Light of Various Intensity

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D. V. Vetoshkina¹, M. A. Kozuleva¹, V. V. Terentyev¹, E. M. Zhurikova¹, M. M. Borisova-Mubarakshina¹, and B. N. Ivanov^1,a*

¹Institute of Basic Biological Problems, Pushchino Scientific Center for Biological Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia

^* To whom correspondence should be addressed.

Received April 23, 2019; Revised May 23, 2019; Accepted May 23, 2019

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Changes in the light energy distribution between the photosystems 1 and 2 (PS1 and PS2, respectively) due to the reversible migration of a part of the light-harvesting complex (LHC2) between the photosystems (state transitions, ST) have been studied in leaves of barley (Hordeum vulgare) and Arabidopsis thaliana plants upon short-term illumination with light of various intensity that excited predominantly PS2. Changes in the ratio of fluorescence maxima at 745 and 685 nm in the low-temperature (77 K) fluorescence spectrum of chlorophyll a (Chl a) characterizing energy absorption by the PS1 and PS2, respectively, were insufficient for revealing the differences in the STs in barley and Arabidopsis plants at various light intensities, because they were not associated with STs at high-intensity illumination. Light-induced accumulation of the LHC2 phosphorylated proteins Lhcb1 and Lhcb2 involved in the relocation of a part of the LHC2 from PS2 to PS1 in the leaves of both plants decreased with the increase in the light intensity and was more pronounced in barley than in Arabidopsis at the same light intensity. Relaxation of the non-photochemical quenching (NPQ) of Chl a fluorescence after illumination corresponding to the return of the part of LHC2 from PS1 to PS2 was observed in barley leaves in a wider range of increasing light intensities than in Arabidopsis leaves. The differences in the accumulation of phosphorylated Lhcb1 and Lhcb2, as well as in the parameters of NPQ relaxation after illumination, revealed that STs in barley leaves could occur not only at low-but also at high-intensity light, when it is absent in Arabidopsis leaves.

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KEY WORDS: Arabidopsis, barley, photosynthesis, phosphorylation of antenna proteins, chlorophyll a fluorescence

DOI: 10.1134/S0006297919090098

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