Action Spectrum of Photoinhibition in the Diatom Phaeodactylum tricornutum

Havurinne, Vesa; Tyystjärvi, Esa

doi:10.1093/pcp/pcx156

Cited by 23 publications

(18 citation statements)

References 43 publications

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“…If, on one hand, photosynthetic and photoprotective antioxidant pigments increased, which may be also partly explained by the lack of changes in CAT and APX activities, on the other hand, the decreased activity of SOD can lead to the accumulation of lethal superoxide anions and consequent oxidation of several biological components, such as proteins, lipids, and EPA fatty acid [78]. However, a decrease in the energy transduction at the ETC, from Q A to plastoquinone, originated a lethal situation of increased redox accumulation in the affected photosystems [79]. Therefore, the energy reaching the PS I was lower, although the effectiveness of the energy transport from PQH 2 to the PS I was not affected (RE 0 /RC), and even increased under the highest glyphosate-based herbicide concentrations.…”

Section: Discussionmentioning

confidence: 99%

Glyphosate-Based Herbicide Toxicophenomics in Marine Diatoms: Impacts on Primary Production and Physiological Fitness

et al. 2020

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Glyphosate is the main active component of the commercial formulation Roundup®, the most widely used chemical herbicide worldwide. However, its potential high toxicity to the environment and throughout trophic webs has come under increasing scrutiny. The present study aims to investigate the application of bio-optical techniques and their correlation to physiological and biochemical processes, including primary productivity, oxidative stress, energy balance, and alterations in pigment and lipid composition in Phaeodactylum tricornutum, a representative species of marine diatoms, using the case study of its response to the herbicide glyphosate-based Roundup® formulation, at environmentally relevant concentrations. Cultures were exposed to the herbicide formulation representing effective glyphosate concentrations of 0, 10, 50, 100, 250, and 500 μg L−1. Results showed that high concentrations decreased cell density; furthermore, the inhibition of photosynthetic activity was not only caused by the impairment of electron transport in the thylakoids, but also by a decrease of antioxidant capacity and increased lipid peroxidation. Nevertheless, concentrations of one of the plastidial marker fatty acids had a positive correlation with the highest concentration as well as an increase in total protein. Cell energy allocation also increased with concentration, relative to control and the lowest concentration, although culture growth was inhibited. Pigment composition and fatty acid profiles proved to be efficient biomarkers for the highest glyphosate-based herbicide concentrations, while bio-optical data separated controls from intermediate concentrations and high concentrations.

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Section: Discussionmentioning

confidence: 99%

Glyphosate-Based Herbicide Toxicophenomics in Marine Diatoms: Impacts on Primary Production and Physiological Fitness

et al. 2020

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“…NPQ is one such mechanism, as NPQ phenotypes cannot be seen in isolated thylakoids with completely unstacked grana (Goss et al 2007), unless artificially induced (Gilmore andYamamoto 1992, Krieger et al 1992). On the other hand, the kPI value of hit2 is less than half of that of CC124, although NPQ does not lower the kPI value by more than 25% in plants (Sarvikas et al 2006), and the protective efficiency of NPQ is relatively small also in the microalga Phaeodactylum tricornutum (Havurinne and Tyystjärvi 2017). However, hit2 has almost twice as high NPQ than CC124 (Schierenbeck et al 2015), and it is therefore obvious that the strong NPQ contributes to the slow photoinhibition in hit2.…”

Section: Fig 4 Ratios Between Chlorophylls and Biomass (A) Carotenmentioning

confidence: 94%

Photoinhibition and continuous growth of the wild-type and a high-light tolerant strain of Chlamydomonas reinhardtii

Virtanen¹,

Valev²,

Kruse³

et al. 2019

Photosynt.

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The volumetric productivity of the highlight tolerant strain hit2 of Chlamydomonas reinhardtii was found to be higher than that of the parental strain CC124 during continuous growth at PPFD from 200 to 1,500 µmol m-2 s-1. At PPFD of 1,250 µmol m-2 s-1 , hit2 produced 2.53 ± 0.18 and CC124 produced 2.05 ± 0.12 g(biomass) dm-3 d-1. The rate constant of photoinhibition of hit2 was less than half of that of CC124, suggesting that hit2 produces more biomass than CC124 because hit2 does not need to allocate as much resources for PSII repair as CC124. Growth in high light triggered similar loss of chlorophyll, increase in the carotenoid-to-chlorophyll ratio, and decrease in PSI fluorescence in both strains. Thermoluminescence B band was shifted toward the Q band in hit2, suggesting that low redox potential of the QB/QBpair contributes to the photoinhibition tolerance of hit2.

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“…Light regime, including light intensity, light quality and light/dark cycle, is indispensable in the mixotrophic cultivation. In P. tricornutum, Fx binds with Chl a + c and proteins to form FCP complex (Durnford et al, 1999), playing an important role in light harvesting and non-photochemical quenching (NPQ) (Havurinne and Tyystjarvi, 2017;Wang et al, 2019). Different from other microalgae, the specific structure of FCP in P. tricornutum allows it to capture blue-green light and supports its application in artificial cultivation system (Wang et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Improving Fucoxanthin Production in Mixotrophic Culture of Marine Diatom Phaeodactylum tricornutum by LED Light Shift and Nitrogen Supplementation

Yang

Dong

2020

Front. Bioeng. Biotechnol.

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Fucoxanthin (Fx), a kind of primary carotenoids in brown seaweeds and diatoms, has attractive efficacy in human's healthcare including loss weight, the prevention of diabetes and Alzheimer's disease. Marine diatom Phaeodactylum tricornutum is now realized as a promising producer for commercial Fx production due to its higher content of Fx than brown seaweeds with easily artificial cultivation and Fx extraction. In the present study, to improve Fx production in P. tricornutum, the mixotrophic cultures were applied to optimize initial cell density, light intensity, light regime and nitrogen supplementation. The results showed that the higher initial cell density (1 × 10 7 cells mL −1) and lower light intensity (20 µmol m −2 s −1) were favorable for biomass production and Fx accumulation. The maximal Fx content [16.28 mg g −1 dry weight (DW)] could be achieved under blue light (BL), but the highest biomass concentration (5.53 g L −1) could be attained under red: blue light (R: B, 6:1) in the batch culture. A novel twophase culture approach was developed to increase the biomass concentration to the highest value (6.52 g L −1) with the maximal productivity of Fx (8.22 mg L −1 d −1) through light shift from R:B ratio (6:1) in phase 1 to R:B ratio (5:1) by enhancing BL and tryptone addition in phase 2. The content and intracellular amount of Fx were also increased 8% and 12% in phase 2 compared to phase 1. The expression levels analysis revealed that genes encoding phytoene synthase (PSY), zeaxanthin epoxidase (ZEP), and fucoxanthin-chlorophyll-protein b (FCPb) were upregulated significantly, with downregulation of the gene encoding violaxanthin de-epoxidase (VDE), leading to the improvement of Fx in phase 2. The present study demonstrated the two-phase culture strategy could promote Fx productivity through enhancing biomass production and increasing Fx content, indicating that strengthening BL coupled with adding tryptone were effective to facilitate Fx production by mixotrophic cultivation of marine diatom P. tricornutum.

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Action Spectrum of Photoinhibition in the Diatom Phaeodactylum tricornutum

Cited by 23 publications

References 43 publications

Glyphosate-Based Herbicide Toxicophenomics in Marine Diatoms: Impacts on Primary Production and Physiological Fitness

Glyphosate-Based Herbicide Toxicophenomics in Marine Diatoms: Impacts on Primary Production and Physiological Fitness

Photoinhibition and continuous growth of the wild-type and a high-light tolerant strain of Chlamydomonas reinhardtii

Improving Fucoxanthin Production in Mixotrophic Culture of Marine Diatom Phaeodactylum tricornutum by LED Light Shift and Nitrogen Supplementation

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