In an ancient vascular plant the intermediate relaxing component of NPQ depends on a reduced stroma: Evidence from dithiothreitol treatment

Ferroni, Lorenzo; Colpo, Andrea; Baldisserotto, Costanza; Pancaldi, Simonetta

doi:10.1016/j.jphotobiol.2020.112114

Cited by 11 publications

(16 citation statements)

References 68 publications

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“…Additionally, the kinetics of the middle phase of NPQ relaxation (1300–1540 s) seems to be partially attributable to the Z pool, as the rate of relaxation was substantially lower in the DTT-fed leaves than in the control condition. It has been reported [ 8 ] that DTT causes a strong dose-dependent decrease in the amplitude of NPQ dark relaxation due to its interference with the chloroplast redox state. The retardation of epoxidation kinetics in DTT samples might also be correlated with the decrease in PSII quantum efficiency [ 53 ] observed in WL, GL, and BL plants.…”

Section: Discussionmentioning

confidence: 99%

“…Fluorescence yields obtained during the analysis were combined to calculate the Stern–Volmer NPQ = (Fm − Fm′)/Fm′ (where Fm′ is the maximal level of chlorophyll fluorescence in light) and the complementary effective quantum yield of PSII photochemistry ΦPSII = (Fm′ − F)/Fm′ (where F is fluorescence yield in conjunction with an applied saturation pulse) [ 28 ], the non-regulated energy dissipation ΦNO = 1/(NPQ + 1 + qL(Fm/Fo − 1)) (where qL is the coefficient of photochemical quenching based on the lake model of PSII antenna pigment organization) and regulated energy dissipation ΦNPQ = 1 − ΦPSII − ΦNO [ 8 , 29 ]. The assessed NPQ value exceeded unity; thus, its value is presented as NPQ/4 for better correspondence with ΦNPQ.…”

Section: Methodsmentioning

confidence: 99%

“…First, energy-dependent quenching, qE, is turned on rapidly by an increase in thylakoid lumen proton concentration, followed by protonation of the thylakoid membrane protein, photosystem II (PSII) subunit S (PsbS) [ 6 ], and reversible conversion of xanthophyll pigments. qE follows the variations of the transmembrane proton gradient (ΔpH), thus its induction and relaxation typically develop within a few minutes (1–3 min) [ 7 , 8 ]. For qE, it is proposed that PsbS promotes energy quenching as it triggers the undocking of light-harvesting complex II (LHCII) from the PSII core [ 9 ], thus promoting antenna oligomerization.…”

Section: Introductionmentioning

confidence: 99%

“…Second, qZ, another NPQ component, is detectable within 10–15 min and is related to violaxanthin (V) de-epoxidation [ 9 ] but not to PsbS [ 8 ]. Thus, the qZ component is strictly related to the xanthophyll cycle activity [ 11 ].…”

Section: Introductionmentioning

confidence: 99%

“…The mechanism of DTT is likely to be related to its reducing action on disulfide bonds in the VDE molecule [ 20 ]. However, DTT does not interfere with the development of the trans-thylakoidal ΔpH [ 8 ] regulating qE. Thus, feeding leaves DTT and AsA, which affect VDE activity in opposite ways, could be applied to distinct NPQ components for a better understanding of the influence of light quality on NPQ characteristics and amplitude.…”

Section: Introductionmentioning

confidence: 99%

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Light Quality-Dependent Regulation of Non-Photochemical Quenching in Tomato Plants

Trojak

Skowron

2021

Biology

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Photosynthetic pigments of plants capture light as a source of energy for photosynthesis. However, the amount of energy absorbed often exceeds its utilization, thus causing damage to the photosynthetic apparatus. Plants possess several mechanisms to minimize such risks, including non-photochemical quenching (NPQ), which allows them to dissipate excess excitation energy in the form of harmless heat. However, under non-stressful conditions in indoor farming, it would be favorable to restrict the NPQ activity and increase plant photosynthetic performance by optimizing the light spectrum. Towards this goal, we investigated the dynamics of NPQ, photosynthetic properties, and antioxidant activity in the leaves of tomato plants grown under different light qualities: monochromatic red (R), green (G), or blue (B) light (L) at 80 µmol m−2 s−1 and R:G:B = 1:1:1 (referred to as the white light (WL)) at 120 µmol m−2 s−1. The results confirm that monochromatic BL increased the quantum efficiency of PSII and photosynthetic pigments accumulation. The RL and BL treatments enhanced the NPQ amplitude and showed negative effects on antioxidant enzyme activity. In contrast, plants grown solely under GL or WL presented a lower amplitude of NPQ due to the reduced accumulation of NPQ-related proteins, photosystem II (PSII) subunit S (PsbS), PROTON GRADIENT REGULATION-LIKE1 (PGRL1), cytochrome b6f subunit f (cytf) and violaxanthin de-epoxidase (VDE). Additionally, we noticed that plants grown under GL or RL presented an increased rate of lipid peroxidation. Overall, our results indicate the potential role of GL in lowering the NPQ amplitude, while the role of BL in the RGB spectrum is to ensure photosynthetic performance and photoprotective properties.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Light Quality-Dependent Regulation of Non-Photochemical Quenching in Tomato Plants

Trojak

Skowron

2021

Biology

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Ultrastructural organization of the thylakoid system during the afternoon relocation of the giant chloroplast in Selaginella martensii Spring (Lycopodiophyta)

Colpo,

Demaria,

Boldrini

et al. 2023

Protoplasma

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Within the ancient vascular plant lineage known as lycophytes, many Selaginella species contain only one giant chloroplast in the upper epidermal cells of the leaf. In deep-shade species, such as S. martensii, the chloroplast is cup-shaped and the thylakoid system differentiates into an upper lamellar region and a lower granal region (bizonoplast). In this report, we describe the ultrastructural changes occurring in the giant chloroplast hosted in the epidermal cells of S. martensii during the daily relocation of the organelle. The process occurs in up to ca. 40% of the microphylls without the plants being exposed to high-light flecks. The relocated chloroplast loses its cup shape: first, it flattens laterally toward the radial cell wall and then assumes a more globular shape. The loss of the conical cell shape, the side-by-side lateral positioning of vacuole and chloroplast, and the extensive rearrangement of the thylakoid system to only granal cooperate in limiting light absorption. While the cup-shaped chloroplast emphasizes the light-harvesting capacity in the morning, the relocated chloroplast is suggested to support the renewal of the thylakoid system during the afternoon, including the recovery of photosystem II (PSII) from photoinhibition. The giant chloroplast repositioning is part of a complex reversible reshaping of the whole epidermal cell.

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Fast chlorophyll a fluorescence induction (OJIP) phenotyping of chlorophyll-deficient wheat suggests that an enlarged acceptor pool size of Photosystem I helps compensate for a deregulated photosynthetic electron flow

Ferroni

Živčák

Kovár

et al. 2022

Journal of Photochemistry and Photobiology B: Biology

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In an ancient vascular plant the intermediate relaxing component of NPQ depends on a reduced stroma: Evidence from dithiothreitol treatment

Cited by 11 publications

References 68 publications

Light Quality-Dependent Regulation of Non-Photochemical Quenching in Tomato Plants

Light Quality-Dependent Regulation of Non-Photochemical Quenching in Tomato Plants

Ultrastructural organization of the thylakoid system during the afternoon relocation of the giant chloroplast in Selaginella martensii Spring (Lycopodiophyta)

Fast chlorophyll a fluorescence induction (OJIP) phenotyping of chlorophyll-deficient wheat suggests that an enlarged acceptor pool size of Photosystem I helps compensate for a deregulated photosynthetic electron flow

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