scholarly journals PSB27: A thylakoid protein enabling Arabidopsis to adapt to changing light intensity

2015 ◽  
Vol 112 (5) ◽  
pp. 1613-1618 ◽  
Author(s):  
Xin Hou ◽  
Aigen Fu ◽  
Veder J. Garcia ◽  
Bob B. Buchanan ◽  
Sheng Luan
Keyword(s):  
Photosystem Ii ◽  
Light Intensity ◽  
Light Adaptation ◽  
Light Exposure ◽  
Starch Accumulation ◽  
State Transitions ◽  
Potential Candidate ◽  
Subsequent Work ◽  
Variable Intensity ◽  
Changing Light

In earlier studies we have identified FKBP20-2 and CYP38 as soluble proteins of the chloroplast thylakoid lumen that are required for the formation of photosystem II supercomplexes (PSII SCs). Subsequent work has identified another potential candidate functional in SC formation (PSB27). We have followed up on this possibility and isolated mutants defective in the PSB27 gene. In addition to lack of PSII SCs, mutant plants were severely stunted when cultivated with light of variable intensity. The stunted growth was associated with lower PSII efficiency and defective starch accumulation. In response to high light exposure, the mutant plants also displayed enhanced ROS production, leading to decreased biosynthesis of anthocyanin. Unexpectedly, we detected a second defect in the mutant, namely in CP26, an antenna protein known to be required for the formation of PSII SCs that has been linked to state transitions. Lack of PSII SCs was found to be independent of PSB27, but was due to a mutation in the previously described cp26 gene that we found had no effect on light adaptation. The present results suggest that PSII SCs, despite being required for state transitions, are not associated with acclimation to changing light intensity. Our results are consistent with the conclusion that PSB27 plays an essential role in enabling plants to adapt to fluctuating light intensity through a mechanism distinct from photosystem II supercomplexes and state transitions.

Arabidopsis PsbP-Like Protein 1 Facilitates the Assembly of the Photosystem II Supercomplexes and Optimizes Plant Fitness under Fluctuating Light

2020 ◽  
Vol 61 (6) ◽  
pp. 1168-1180
Author(s):  
Yufen Che ◽  
Shoko Kusama ◽  
Shintaro Matsui ◽  
Marjaana Suorsa ◽  
Takeshi Nakano ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Light Intensity ◽  
Early Stage ◽  
Light Harvesting Complexes ◽  
Green Plants ◽  
Fluctuating Light ◽  
Exact Function ◽  
Stroma Lamellae ◽  
Assembly Factor ◽  
Changing Light

Abstract In green plants, photosystem II (PSII) forms multisubunit supercomplexes (SCs) containing a dimeric core and light-harvesting complexes (LHCs). In this study, we show that Arabidopsis thaliana PsbP-like protein 1 (PPL1) is involved in the assembly of the PSII SCs and is required for adaptation to changing light intensity. PPL1 is a homolog of PsbP protein that optimizes the water-oxidizing reaction of PSII in green plants and is required for the efficient repair of photodamaged PSII; however, its exact function has been unknown. PPL1 was enriched in stroma lamellae and grana margins and associated with PSII subcomplexes including PSII monomers and PSII dimers, and several LHCII assemblies, while PPL1 was not detected in PSII–LHCII SCs. In a PPL1 null mutant (ppl1-2), assembly of CP43, PsbR and PsbW was affected, resulting in a reduced accumulation of PSII SCs even under moderate light intensity. This caused the abnormal association of LHCII in ppl1-2, as indicated by lower maximal quantum efficiency of PSII (Fv/Fm) and accelerated State 1 to State 2 transitions. These differences would lower the capability of plants to adapt to changing light environments, thereby leading to reduced growth under natural fluctuating light environments. Phylogenetic and structural analyses suggest that PPL1 is closely related to its cyanobacterial homolog CyanoP, which functions as an assembly factor in the early stage of PSII biogenesis. Our results suggest that PPL1 has a similar function, but the data also indicate that it could aid the association of LHCII with PSII.

scholarly journals Photosystem II Photochemistry and Phycobiliprotein of the Red AlgaeKappaphycus alvareziiand Their Implications for Light Adaptation

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Xiangyu Guan ◽  
Jinfeng Wang ◽  
Jianyi Zhu ◽  
Chunyan Yao ◽  
Jianguo Liu ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Light Intensity ◽  
Red Algae ◽  
Light Adaptation ◽  
Kappaphycus Alvarezii ◽  
Algal Species ◽  
Light Yield ◽  
Raw Material ◽  
Photosystem Ii Photochemistry ◽  
Pharmaceutical Industries

Photosystem II photochemistry and phycobiliprotein (PBP) genes of red algaeKappaphycus alvarezii, raw material ofκ-carrageenan used in food and pharmaceutical industries, were analyzed in this study. Minimum saturating irradiance (Ik) of this algal species was less than 115 μmol m−2 s−1. Its actual PSII efficiency (yield II) increased when light intensity enhanced and decreased when light intensity reached 200 μmol m−2 s−1. Under dim light, yield II declined at first and then increased on the fourth day. Under high light, yield II retained a stable value. These results indicate thatK. alvareziiis a low-light-adapted species but possesses regulative mechanisms in response to both excessive and deficient light. Based on the PBP gene sequences,K. alvarezii, together with other red algae, assembled faster and showed a closer relationship with LL-Prochlorococcuscompared to HL-Prochlorococcus. Many amino acid loci in PBP sequences ofK. alvareziiwere conserved with those of LL-Prochlorococcus. However, loci conserved with HL-Prochlorococcusbut divergent with LL-Prochlorococcuswere also found. The diversities of PE and PC are proposed to have played some roles during the algal evolution and divergence of light adaption.

scholarly journals PHOTOKINESIS AND TONIC EFFECT OF LIGHT IN UNIONICOLA

1932 ◽  
Vol 16 (2) ◽  
pp. 349-355 ◽  
Author(s):  
John H. Welsh
Keyword(s):  
Light Intensity ◽  
Simple Relation ◽  
Combined Effect ◽  
Direct Proportion ◽  
Water Mite ◽  
Locomotor Muscles ◽  
Leg Movement ◽  
Changing Light ◽  
Effect Of Light

1. The speed of progression of Unionicola, a water mite, is influenced by light; and over a certain range increases as a function of the light intensity. 2. The relation between speed and light intensity is not a simple one, as the speed of progression is due to the combined effect of amplitude of steps and frequency of leg movement. 3. The amplitude of stride increases in direct proportion to the logarithm of the light intensity, while the frequency of stepping has no such simple relation to intensity. 4. The change in length of stride with changing light intensity indicates a tonic effect of light on the locomotor muscles. Such an effect has been observed previously in studies of orientation, due to unequal illumination, which produces changes in posture.

scholarly journals State transitions in the cyanobacterium Synechococcus elongatus 7942 involve reversible quenching of the photosystem II core

2018 ◽  
Vol 1859 (10) ◽  
pp. 1059-1066 ◽  
Author(s):  
Reza Ranjbar Choubeh ◽  
Emilie Wientjes ◽  
Paul C. Struik ◽  
Diana Kirilovsky ◽  
Herbert van Amerongen
Keyword(s):  
Photosystem Ii ◽  
Synechococcus Elongatus ◽  
State Transitions

scholarly journals Elaborate pupils in skates may help camouflage the eye

2018 ◽  
Author(s):  
Sean Youn ◽  
Corey Okinaka ◽  
Lydia M Mäthger
Keyword(s):  
Light Intensity ◽  
Spatial Frequency ◽  
Experimental Evidence ◽  
Pupillary Response ◽  
Pupil Dilation ◽  
Primary Factor ◽  
Natural Substrate ◽  
Spatial Frequencies ◽  
Pupillary Responses ◽  
Changing Light

AbstractThe little skate Leucoraja erinacea has elaborately shaped pupils, whose characteristics and functions have not been studied extensively. It has been suggested that such pupil shapes may camouflage the eye; yet, no experimental evidence has been presented to support this claim. Skates are bottom-dwellers that often bury into the substrate with their eyes protruding. If these pupils serve any camouflage function, we expect there to be a pupillary response related to the spatial frequency (“graininess”) of the background against which the eye is viewed. Here, we tested whether skate pupils dilate or constrict in response to background spatial frequency. We placed skates on background substrates with different spatial frequencies and recorded pupillary responses at three light intensities. In experiment 1, the skates’ pupillary response to three artificial checkerboards of different spatial frequencies was recorded. Skates responded to changing light intensity with pupil dilation/constriction; yet, their pupils did not change in response to spatial frequency. In experiment 2, in which skates could bury into three natural substrates with different spatial frequencies, such that their eyes protruded above the substrate, the pupils showed a subtle but statistically significant response to changes in substrate spatial frequency. Given the same light intensity, the smaller the spatial frequency of the natural substrate, the more constricted the pupil. While light intensity is the primary factor determining pupil dilation, these experiments are the first to show that pupils also change in response to background spatial frequency, which suggests that the pupil may aid in camouflaging the eye.

Light-Adaptation of Photosystem II Is Mediated by the Plastoquinone Pool†

Biochemistry ◽  
2003 ◽  
Vol 42 (25) ◽  
pp. 7655-7662 ◽  
Author(s):  
Karin A. Åhrling ◽  
Sindra Peterson
Keyword(s):  
Photosystem Ii ◽  
Light Adaptation ◽  
Plastoquinone Pool

In vitro studies on the induction of sporogenous tissue on leaves of cinnamon fern. I. Environmental factors

1972 ◽  
Vol 50 (12) ◽  
pp. 2673-2682 ◽  
Author(s):  
William H. Harvey ◽  
James D. Caponetti
Keyword(s):  
Environmental Factors ◽  
Light Intensity ◽  
Environmental Conditions ◽  
Light Exposure ◽  
Progressive Increase ◽  
Light Phase ◽  
Sporogenous Tissue ◽  
Light Darkness

Intact, set III, cinnamon fern cataphyll and frond primordia, which were shown to have no predisposition to fertility in situ, produced sporangia when excised and cultured under sterile conditions in Knudson's medium supplemented with various levels of sucrose and maintained on 11 different regimens of light, darkness, and temperature for 10 weeks. Increasing levels of sucrose resulted in increased fertility under all environmental conditions, but the highest percentage of fertility was obtained under conditions of continuous dark at 26 °C. As the length of the light phase of the photoperiods decreased, a progressive increase in induction of fertile leaves was observed, suggesting that periods of long light exposure are inhibitory to the initiation of sporangia. Conversely, as the light intensity was increased, an inhibition of sporophyll differentiation occurred. Sporangia excised from dark-induced sporophylls and cultured in the light produced viable spores which germinated yielding haploid gametophytes that ultimately produced sporophytes.

scholarly journals Comprehensive Transcriptome Analysis Revealed the Effects of the Light Quality, Light Intensity, and Photoperiod on Phlorizin Accumulation in Lithocarpus polystachyus Rehd.

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 995 ◽  
Author(s):  
Yantong Zhang ◽  
Limei Lin ◽  
Yuehong Long ◽  
Hongyu Guo ◽  
Zhuo Wang ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Light Intensity ◽  
Light Exposure ◽  
Southern China ◽  
Green Light ◽  
Differentially Expressed ◽  
Chromatography Method ◽  
Pal Activity ◽  
Study Results ◽  
Regulatory Effects

Lithocarpus polystachyus Rehd. is an important medicinal plant species grown in southern China, with phlorizin as its main active substance. The effects of light conditions on phlorizin biosynthesis in L. polystachyus remain unclear. Thus, we analyzed the transcriptomes of L. polystachyus plants cultivated under diverse light qualities, light intensities, and photoperiods. The light treatments resulted in 5977–8027 differentially expressed genes (DEGs), which were functionally annotated based on the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Genes encoding transcription factors from 89 families were differentially expressed after the light treatments, implying these transcription factors are photoresponsive. Phenylalanine ammonia lyase (PAL) and 4-coumarate-CoA ligase (4CL) are the key enzymes for the accumulation of phlorizin. The transcription levels of PAL2, PAL, 4CL1 (DN121614), 4CLL7, and 4CL1 (DN102161) were positively correlated with phlorizin accumulation, suggesting that these genes are important for phlorizin biosynthesis. An ultra-high-performance liquid chromatography method was used to quantify the phlorizin content. Phlorizin accumulated in response to the green light treatment and following appropriate decreases in the light intensity or appropriate increases in the duration of the light exposure. The green light, 2000 lx, and 3000 lx treatments increased the PAL activity of L. polystachyus, but the regulatory effects of the light intensity treatments on PAL activity were relatively weak. This study represents the first comprehensive analysis of the light-induced transcriptome of L. polystachyus. The study results may form the basis of future studies aimed at elucidating the molecular mechanism underlying phlorizin biosynthesis in L. polystachyus. Moreover, this study may be relevant for clarifying the regulatory effects of light on the abundance of bioactive components in medicinal plants.

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