Action spectrum of the redox state of the plastoquinone pool defines its function in plant acclimation

Mattila, Heta; Khorobrykh, Sergey; Hakala-Yatkin, Marja; Havurinne, Vesa; Kuusisto, Iiris; Antal, Taras K.; Tyystjärvi, Taina; Tyystjärvi, Esa

doi:10.1111/tpj.14983

Cited by 19 publications

(34 citation statements)

References 69 publications

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“…As only relative absorption spectra of yellow and green leaves were available, the spectra were normalized by setting the absorptance of the green leaves to 100% at 430 nm; earlier measurements from green leaves (Hogewoning et al 2012;Mattila et al 2020) show over 95% absorptance in this region.…”

Section: Estimation Of the Effect Of Leaf Chlorophyll Content On Sosgmentioning

confidence: 99%

Singlet oxygen, flavonols and photoinhibition in green and senescing silver birch leaves

Mattila

Sotoudehnia

Kuuslampi

et al. 2021

Trees

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Key message Decreased absorptance and increased singlet oxygen production may cause photoinhibition of both PSII and PSI in birch leaves during autumn senescence; however, photosynthetic electron transfer stays functional until late senescence. Abstract During autumn senescence, deciduous trees degrade chlorophyll and may synthesize flavonols. We measured photosynthetic parameters, epidermal flavonols, singlet oxygen production in vivo and photoinhibition of the photosystems (PSII and PSI) from green and senescing silver birch (Betula pendula) leaves. Chlorophyll a fluorescence and P700 absorbance measurements showed that the amounts of both photosystems decreased throughout autumn senescence, but the remaining PSII units stayed functional until ~ 90% of leaf chlorophyll was degraded. An increase in the chlorophyll a to b ratio, a decrease in > 700 nm absorbance and a blue shift of the PSI fluorescence peak at 77 K suggest that light-harvesting complex I was first degraded during senescence, followed by light-harvesting complex II and finally the photosystems. Senescing leaves produced more singlet oxygen than green leaves, possibly because low light absorption by senescing leaves allows high flux of incident light per photosystem. Senescing leaves also induced less non-photochemical quenching, which may contribute to increased singlet oxygen production. Faster photoinhibition of both photosystems in senescing than in green leaves, under high light, was most probably caused by low absorption of light and rapid singlet oxygen production. However, senescing leaves maintained the capacity to recover from photoinhibition of PSII. Amounts of epidermal flavonols and singlet oxygen correlated neither in green nor in senescing leaves of silver birch. Moreover, Arabidopsis thaliana mutants, incapable of synthesizing flavonols, were not more susceptible to photoinhibition of PSII or PSI than wild type plants; screening of chlorophyll absorption by flavonols was, however, small in A. thaliana. These results suggest that flavonols do not protect against photoinhibition or singlet oxygen production in chloroplasts.

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Section: Estimation Of the Effect Of Leaf Chlorophyll Content On Sosgmentioning

confidence: 99%

Singlet oxygen, flavonols and photoinhibition in green and senescing silver birch leaves

Mattila

Sotoudehnia

Kuuslampi

et al. 2021

Trees

Self Cite

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“…The wave phenomenon in Chlamydomonas was found only under hydrogen-producing microaerobic conditions, when PSII activity is partly inhibited (Krishna et al 2019 ). This observation raises the possibility that the PSII:PSI ratio, which have a strong influence on the redox state of the PQ pool following a flash (and also the spectrum of the light should be taken into account in this process, Mattila et al 2020 ) can play an important role in the appearance of the fluorescence wave phenomenon.…”

Section: Introductionmentioning

confidence: 99%

Characterization of the wave phenomenon of flash-induced chlorophyll fluorescence in Chlamydomonas reinhardtii

et al. 2022

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Flash-induced chlorophyll fluorescence relaxation is a powerful tool to monitor the reoxidation reactions of the reduced primary quinone acceptor, QA− by QB and the plastoquinone (PQ) pool, as well as the charge recombination reactions between the donor and acceptor side components of Photosystem II (PSII). Under certain conditions, when the PQ pool is highly reduced (e.g. in microaerobic conditions), a wave phenomenon appears in the fluorescence relaxation kinetics, which reflects the transient reoxidation and re-reduction of QA− by various electron transfer processes, which in cyanobacteria is mediated by NAD(P)H dehydrogenase (NDH-1). The wave phenomenon was also observed and assigned to the operation of type 2 NAD(P)H dehydrogenase (NDH-2) in the green alga Chlamydomonas reinhardtii under hydrogen-producing conditions, which required a long incubation of algae under sulphur deprivation (Krishna et al. J Exp Bot 70 (21):6321–6336, 2019). However, the conditions that induce the wave remained largely uncharacterized so far in microalgae. In this work, we investigated the wave phenomenon in Chlamydomonas reinhardtii under conditions that lead to a decrease of PSII activity by applying hydroxylamine treatment, which impacts the donor side of PSII in combination with a strongly reducing environment of the PQ pool (microaerobic conditions). A similar wave phenomenon could be induced by photoinhibitory conditions (illumination with strong light in the presence of the protein synthesis inhibitor lincomycin). These results indicate that the fluorescence wave phenomenon is activated in green algae when the PSII activity decreases relative to Photosystem I (PS I) activity and the PQ pool is strongly reduced. Therefore, the fluorescence wave could be used as a sensitive indicator of altered intersystem electron transfer processes, e.g. under stress conditions.

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“…The question of comparability of results between different illumination set-ups may become even more urgent with the advent of LED based illumination systems that are increasingly used now for plant growth ( Seiler et al, 2017 ; Matsuda et al, 2021 ). A recent study investigated wavelength-specific effects on the redox state of the PQ pool using monochromatic LED illumination of different colors ( Mattila et al, 2020 ). The authors observed varying efficiencies within the 400–700 nm range.…”

Section: Discussionmentioning

confidence: 99%

Effectiveness of Light-Quality and Dark-White Growth Light Shifts in Short-Term Light Acclimation of Photosynthesis in Arabidopsis

et al. 2022

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Photosynthesis needs to run efficiently under permanently changing illumination. To achieve this, highly dynamic acclimation processes optimize photosynthetic performance under a variety of rapidly changing light conditions. Such acclimation responses are acting by a complex interplay of reversible molecular changes in the photosynthetic antenna or photosystem assemblies which dissipate excess energy and balance uneven excitation between the two photosystems. This includes a number of non-photochemical quenching processes including state transitions and photosystem II remodeling. In the laboratory such processes are typically studied by selective illumination set-ups. Two set-ups known to be effective in a highly similar manner are (i) light quality shifts (inducing a preferential excitation of one photosystem over the other) or (ii) dark-light shifts (inducing a general off-on switch of the light harvesting machinery). Both set-ups result in similar effects on the plastoquinone redox state, but their equivalence in induction of photosynthetic acclimation responses remained still open. Here, we present a comparative study in which dark-light and light-quality shifts were applied to samples of the same growth batches of plants. Both illumination set-ups caused comparable effects on the phosphorylation of LHCII complexes and, hence, on the performance of state transitions, but generated different effects on the degree of state transitions and the formation of PSII super-complexes. The two light set-ups, thus, are not fully equivalent in their physiological effectiveness potentially leading to different conclusions in mechanistic models of photosynthetic acclimation. Studies on the regulation of photosynthetic light acclimation, therefore, requires to regard the respective illumination test set-up as a critical parameter that needs to be considered in the discussion of mechanistic and regulatory aspects in this subject.

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Action spectrum of the redox state of the plastoquinone pool defines its function in plant acclimation

Cited by 19 publications

References 69 publications

Singlet oxygen, flavonols and photoinhibition in green and senescing silver birch leaves

Singlet oxygen, flavonols and photoinhibition in green and senescing silver birch leaves

Characterization of the wave phenomenon of flash-induced chlorophyll fluorescence in Chlamydomonas reinhardtii

Effectiveness of Light-Quality and Dark-White Growth Light Shifts in Short-Term Light Acclimation of Photosynthesis in Arabidopsis

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