Singlet Oxygen Production by PSII Under Light Stress: Mechanism, Detection and the Protective role of β-Carotene

Telfer, Alison

doi:10.1093/pcp/pcu040

Cited by 131 publications

(97 citation statements)

References 66 publications

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“…However, it is notable that the application of the scavenger His with PEG treatment significantly delayed cell death and reduced the decrease in the rate of elongation. His is specific for singlet oxygen (Telfer, 2014) and, as demonstrated here, did not affect the other ROS. Hence, the appearance of singlet oxygen in the osmotic stress response is not only symptomatic of imminent cellular demise but is also a necessary component.…”

Section: Discussionsupporting

confidence: 68%

Singlet Oxygen Plays an Essential Role in the Root’s Response to Osmotic Stress

Chen

Fluhr

2018

Plant Physiol.

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As SOSG fluorescence indicated the presence of singlet oxygen both before and after cell death, it is important to consider whether the appearance of singlet oxygen is an essential component of PEG-induced . Relationship between integrity of the quiescent center and root elongation. A, Fluorescence resulting from SCR::GFP expression in the endodermis and quiescent center. Roots were exposed to 30% PEG for 1 to 8 h and counterstained with propidium iodide (PI). The median plane was imaged where opaque regions in PI staining indicate cell death. Arrows indicate the quiescent center; scale bars, 100 μm. B, Root elongation rate following exposure to PEG. Student's t test, alpha = 0.05; difference in letters signifies a P < 0.05 significant difference; error bars are se, n ≥ 13. stress response or a symptom of cell death. In the former possibility, singlet oxygen would play a direct role in the PEG responses, and specific scavengers of singlet oxygen should mitigate its action. To test this, His, a membrane-permeable specific scavenger of singlet oxygen, was employed. His rapidly forms specific endoperoxides in the presence of singlet oxygen. It is a weaker scavenger of hydroxyl radicals and hydrogen peroxide and does not scavenge superoxide (Matheson et al., 1975; Cai et al., 1995; Ishibashi et al., 1996). The specificity of His as a scavenger for singlet oxygen as opposed to the other ROS is shown in Supplemental Figure S6. As indicated in Figure 6, A and B, His readily mitigates the appearance of singlet oxygen as measured by SOSG. Significantly, the amount of cell death was reduced by 50% ( Fig. 6B) and, as shown in Figure 6C, the presence of His alleviated the repression of the rate of root elongation by PEG. In all, the results lend support for an active role of singlet oxygen in the response to osmotic stress.The light-independent origin of singlet oxygen is unclear. SHAM is a nonspecific inhibitor of mitochondrial Composite of multiple confocal images of ROS accumulation in root tips exposed to 30% PEG for different durations. A, Composite of confocal images that were collated for each specific signal (ROS probes and propidium iodide stain). Multiple image acquisitions for each time point were aligned manually by rotation and overlaid to create the average composite image using Matlab script. The Look Up Table was set to "Fire" and scaled to maximum as white and minimum as blue. Shown are 1 O 2 , measured using the SOSG probe; NO, measured using the DAF-FM-AM probe; O − 2, measured using the BesSo-AM probe; H 2 O 2 , measured using the Bes-H 2 O 2 -AC probe, and cell permeability, measured using staining by propidium iodide. B, Schematic representation of the fluorescence shown in A. Scale bar, 100 µm. Figure 5. Singlet oxygen-and hydrogen peroxide-specific gene expression in roots. A, Transcript levels were measured by RT-qPCR analysis at 0, 1, 2, and 3 h after treatment with 30% PEG. B, Specificity of gene expression. The transcript level fold change in roots; no treatment (Control); treatment for 2 h in ...

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Section: Discussionsupporting

confidence: 68%

Singlet Oxygen Plays an Essential Role in the Root’s Response to Osmotic Stress

Chen

Fluhr

2018

Plant Physiol.

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“…Furthermore, they also reported that the Arabidopsis szl1 mutant, which contains less b-carotene than the wildtype, is susceptible to PSI photoinhibition under highlight and low-temperature conditions. This means that 1 O 2 produced in PSI caused PSI photoinhibition because b-carotene is a major 1 O 2 quencher (Telfer, 2014). Therefore, we suggest that 1 O 2 is actually produced in PSI, and 1 O 2 is involved in PSI photoinhibition in higher plants.…”

Section: Discussionmentioning

confidence: 74%

Superoxide and Singlet Oxygen Produced within the Thylakoid Membranes Both Cause Photosystem I Photoinhibition

et al. 2016

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Photosystem I (PSI) photoinhibition suppresses plant photosynthesis and growth. However, the mechanism underlying PSI photoinhibition has not been fully clarified. In this study, in order to investigate the mechanism of PSI photoinhibition in higher plants, we applied repetitive short-pulse (rSP) illumination, which causes PSI-specific photoinhibition in chloroplasts isolated from spinach leaves. We found that rSP treatment caused PSI photoinhibition, but not PSII photoinhibition in isolated chloroplasts in the presence of O 2 . However, chloroplastic superoxide dismutase and ascorbate peroxidase activities failed to protect PSI from its photoinhibition. Importantly, PSI photoinhibition was largely alleviated in the presence of methyl viologen, which stimulates the production of reactive oxygen species (ROS) at the stromal region by accepting electrons from PSI, even under the conditions where CuZn-superoxide dismutase and ascorbate peroxidase activities were inactivated by KCN. These results suggest that the ROS production site, but not the ROS production rate, is critical for PSI photoinhibition. Furthermore, we found that not only superoxide (O 2 2 ) but also singlet oxygen ( 1 O 2 ) is involved in PSI photoinhibition induced by rSP treatment. From these results, we suggest that PSI photoinhibition is caused by both O 2 2 and 1 O 2 produced within the thylakoid membranes when electron carriers in PSI become highly reduced. Here, we show, to our knowledge, new insight into the PSI photoinhibition in higher plants.

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“…In contrast to the two other species, in N. phyllepta, DD de-epoxidation was accompanied by DD de novo synthesis, a way to enhance the capacity to further synthesize DT in case of prolonged stress . Probably due to the shortness of high salinity exposure, there was no significant increase in fucoxanthin and β-carotene, a well-known pigment response to oxidative stress additional to the XC (Dambeck and Sandmann, 2014;Telfer, 2014). As expected, NPQ m was higher in B lucens than in N. phyllepta, while it was higher than previously observed in P. vanheurckii probably due to i) different growth light conditions which generated a higher DES, and ii) the different way of measuring NPQ (RLCs vs. Non-Sequential Light Curves -NSLCs) (Barnett et al, in press).…”

Section: Differential Photosynthetic and Photoprotective Response To mentioning

confidence: 99%

Combined effect of high light and high salinity on the regulation of photosynthesis in three diatom species belonging to the main growth forms of intertidal flat inhabiting microphytobenthos

Juneau

Barnett

Méléder

et al. 2015

Journal of Experimental Marine Biology and Ecology

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International audienceThe strong biological production of estuarine intertidal flats is mainly supported by benthic diatoms in temperate areas. Their photosynthetic productivity is largely driven by changes in light intensity and temperature at the surface of sediment flats during emersion. The impact of an increase in salinity of the upper-layer sediment pore-water during emersion, which is often coupled with high light (HL), has been less studied. Furthermore, benthic diatoms show several growth forms which inhabit specific sediment types where the pore-water salinity can differentially vary due to the degree of cohesion of sediment grains. So far, no study explored if the main growth forms of benthic diatoms (i.e. epipelon, epipsammon and tychoplankton) show different photophysiological response to a combine high salinity-HL stress. Based on field monitoring, we compared the photophysiology (photosynthetic efficiency and photoprotection) of three representatives of the main growth forms during a short high salinity coupled with a moderate HL stress and stable optimal temperature, i.e. experimental conditions reproducing Spring environmental conditions in intertidal flats by the Atlantic French coast. Our results show that all growth forms reacted to HL exposure alone, as expected. While the epipelon representative was relatively insensitive to high salinity alone and combined with HL, the tychoplankton representative was highly sensitive to both, and the epipsammon representative was sensitive mainly to the stress combination. These specific responses fitted well with i) their natural habitat (i.e. more or less cohesive sediment) for which light climate and changes in salinity are different, ii) their growth form (i.e. motile, immotile or amphibious) which determines their probability to be confronted to a combined high salinity-HL stress. Hence, the negative effect of high salinity on photosynthetic efficiency of benthic diatoms appears to be mostly restricted to epipsammon and tychoplankton, and in field conditions, its effect probably remains negligible compared to HL stress

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Singlet Oxygen Production by PSII Under Light Stress: Mechanism, Detection and the Protective role of β-Carotene

Cited by 131 publications

References 66 publications

Singlet Oxygen Plays an Essential Role in the Root’s Response to Osmotic Stress

Singlet Oxygen Plays an Essential Role in the Root’s Response to Osmotic Stress

Superoxide and Singlet Oxygen Produced within the Thylakoid Membranes Both Cause Photosystem I Photoinhibition

Combined effect of high light and high salinity on the regulation of photosynthesis in three diatom species belonging to the main growth forms of intertidal flat inhabiting microphytobenthos

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