phyB and HY5 are Involved in the Blue Light-Mediated Alleviation of Dormancy of Arabidopsis Seeds Possibly via the Modulation of Expression of Genes Related to Light, GA, and ABA

Light is one of the most important environmental factors regulating seed germination. It is known that light inhibits seed germination of some monocotyledonous species and that it is mostly related to the blue wavelength of the spectrum received by cryptochromes (cry). Research has also found that the red light (R) stimulates germination of dicotyledonous seeds and that this reaction involves mainly phytochromes (phy). Surprisingly, up to date, the role and the mechanism of action of blue light (BL) in seed biology of dicot plants is still very poorly understood and some questions are unexplained, e.g., whether BL plays a role in regulation of dicot seeds dormancy and/or germination? If, so what particular elements of light signaling pathway are involved in modulation of this(ese) process(es)? Also, is the BL action in regulation of dicot seeds dormancy and/or germination maybe due to changes of expression of genes related to metabolism and/or signaling of two phytohormones controlling seed-related events, such as gibberellins (GA) and abscisic acid (ABA)? To answer these intriguing questions, the combination of biological, transcriptomic, and genetic approaches was performed in this particular study. The germination tests show that freshly harvested wild type (WT) Arabidopsis thaliana Col-0 seeds are dormant and do not germinate in darkness (at 25 °C), while nondormant (after-ripened) seeds germinate well in these conditions. It is also proven that dormancy of seeds of this species is released in the presence of white and/or BL (λ = 447 nm) when placed at 25 °C. Presented here, novel results emphasize the role of BL in dormancy alleviation of dicot seeds, indicating that this wavelength of light spectrum received by phyB induces this process and that the sensitivity to this stimulus depends on the depth of seed dormancy. In addition, it is demonstrated that various elements of phy-mediated pathway can be used in response to the signal induced by BL in germinating dormant seeds of Arabidopsis. The quantitative real time PCR analysis supported by results of germination tests of WT, T-DNA insertion mutants (i.e., hy5, hfr1, and laf1) and overexpression transformants of Arabidopsis seeds (i.e., 35S:OE:HY5, 35S:OE:HYH, 35S:OE:HFR1, and 35S:OE:LAF1) revealed that the HY5 gene coding transcription factor is most probably responsible for the control of expression of genes involved in GA/ABA metabolism and/or signaling pathways during BL-dependent dormancy alleviation of Arabidopsis seeds, while biological functions of HYH and HFR1 are associated with regulation of germination. The model of BL action in regulation of dormancy alleviation and germination potential of Arabidopsis seeds is proposed.

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The Preferences of Different Cultivars of Lettuce Seedlings (Lactuca sativa L.) for the Spectral Composition of Light

Agronomy ◽

10.3390/agronomy11061211 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1211

Author(s):

Barbara Frąszczak ◽

Monika Kula-Maximenko

Keyword(s):

Chlorophyll Content ◽

Blue Light ◽

White Light ◽

Leaf Shape ◽

Red Light ◽

Spectral Composition ◽

Fresh Weight ◽

Light Spectrum ◽

Dark Green ◽

Relative Chlorophyll Content

The spectrum of light significantly influences the growth of plants cultivated in closed systems. Five lettuce cultivars with different leaf colours were grown under white light (W, 170 μmol m−2 s−1) and under white light with the addition of red (W + R) or blue light (W + B) (230 μmol m−2 s−1). The plants were grown until they reached the seedling phase (30 days). Each cultivar reacted differently to the light spectrum applied. The red-leaved cultivar exhibited the strongest plasticity in response to the spectrum. The blue light stimulated the growth of the leaf surface in all the plants. The red light negatively influenced the length of leaves in the cultivars, but it positively affected their number in red and dark-green lettuce. It also increased the relative chlorophyll content and fresh weight gain in the cultivars containing anthocyanins. When the cultivars were grown under white light, they had longer leaves and higher value of the leaf shape index. The light-green cultivars had a greater fresh weight. Both the addition of blue and red light significantly increased the relative chlorophyll content in the dark-green cultivar. The spectrum enhanced with blue light had positive influence on most of the parameters under analysis in butter lettuce cultivars. These cultivars were also characterised by the highest absorbance of blue light.

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Identification and expression of the trehalose-6-phosphate synthase gene family members in tomato exposed to different light spectra

Archives of Biological Sciences ◽

10.2298/abs160325082c ◽

2017 ◽

Vol 69 (1) ◽

pp. 93-101

Author(s):

Zexiong Chen ◽

Juan Lou

Keyword(s):

Plant Growth ◽

Blue Light ◽

White Light ◽

Growth And Development ◽

Light Quality ◽

Red Light ◽

Floral Transition ◽

Stem Length ◽

Pcr Analysis ◽

Phosphate Synthase

Light is the source of energy for plants. Light wavelengths, densities and irradiation periods act as signals directing morphological and physiological characteristics during plant growth and development. To evaluate the effects of light wavelengths on tomato growth and development, Solanum lycopersicum (cv. micro-Tom) seedlings were exposed to different light-quality environments, including white light and red light supplemented with blue light (at ratios of 3:1 and 8;1, respectively). Tomatoes grown under red light supplemented with blue light displayed significantly shorter stem length, a higher number of flower buds and rate of fruit set, but an extremely late flowering compared to white-light-grown plants. To illustrate the mechanism underlying the inhibition of stem growth and floral transition mediated by red/blue light, 10 trehalose-6-phosphate synthase (TPS) genes were identified in tomato, and bioinformatics analysis was performed. qRT-PCR analysis showed that SlTPSs were expressed widely throughout plant development and SlTPS1 was expressed at extremely high levels in stems and buds. Further analysis of several flowering-associated genes and microRNAs showed that the expressions of SlTPS1, SlFT and miR172 were significantly downregulated in tomato grown under red and blue light compared with those grown under white light, whereas miR156 transcript levels were increased. A regulatory model underlying vegetative growth and floral transition regulated by light qualities is presented. Our data provide evidence that light quality strongly affects plant growth and phase transition, most likely via the TPS1-T6P signaling pathway.

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Photosynthetic Physiology of Blue, Green, and Red Light: Light Intensity Effects and Underlying Mechanisms

Frontiers in Plant Science ◽

10.3389/fpls.2021.619987 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jun Liu ◽

Marc W. van Iersel

Keyword(s):

Blue Light ◽

Interactive Effect ◽

Red Light ◽

Green Light ◽

Photosynthetic Photon Flux Density ◽

Interactive Effects ◽

Photon Flux ◽

Photon Flux Density ◽

Light Spectrum ◽

Response Curves

Red and blue light are traditionally believed to have a higher quantum yield of CO2 assimilation (QY, moles of CO2 assimilated per mole of photons) than green light, because green light is absorbed less efficiently. However, because of its lower absorptance, green light can penetrate deeper and excite chlorophyll deeper in leaves. We hypothesized that, at high photosynthetic photon flux density (PPFD), green light may achieve higher QY and net CO2 assimilation rate (An) than red or blue light, because of its more uniform absorption throughtout leaves. To test the interactive effects of PPFD and light spectrum on photosynthesis, we measured leaf An of “Green Tower” lettuce (Lactuca sativa) under red, blue, and green light, and combinations of those at PPFDs from 30 to 1,300 μmol⋅m–2⋅s–1. The electron transport rates (J) and the maximum Rubisco carboxylation rate (Vc,max) at low (200 μmol⋅m–2⋅s–1) and high PPFD (1,000 μmol⋅m–2⋅s–1) were estimated from photosynthetic CO2 response curves. Both QYm,inc (maximum QY on incident PPFD basis) and J at low PPFD were higher under red light than under blue and green light. Factoring in light absorption, QYm,abs (the maximum QY on absorbed PPFD basis) under green and red light were both higher than under blue light, indicating that the low QYm,inc under green light was due to lower absorptance, while absorbed blue photons were used inherently least efficiently. At high PPFD, the QYinc [gross CO2 assimilation (Ag)/incident PPFD] and J under red and green light were similar, and higher than under blue light, confirming our hypothesis. Vc,max may not limit photosynthesis at a PPFD of 200 μmol m–2 s–1 and was largely unaffected by light spectrum at 1,000 μmol⋅m–2⋅s–1. Ag and J under different spectra were positively correlated, suggesting that the interactive effect between light spectrum and PPFD on photosynthesis was due to effects on J. No interaction between the three colors of light was detected. In summary, at low PPFD, green light had the lowest photosynthetic efficiency because of its low absorptance. Contrary, at high PPFD, QYinc under green light was among the highest, likely resulting from more uniform distribution of green light in leaves.

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Germination responses of seeds of Desmodium triflorum

International Journal of Scientific Reports ◽

10.18203/issn.2454-2156.intjscirep20180392 ◽

2018 ◽

Vol 4 (2) ◽

pp. 19 ◽

Cited By ~ 1

Author(s):

Niroj Paudel ◽

Prakash Deep Rai

Keyword(s):

Seed Germination ◽

Blue Light ◽

White Light ◽

Red Light ◽

Light Condition ◽

Dark Condition ◽

Percentage Germination ◽

Negative Effect

Background: Germination of Desmodium triflorum is used for the scarification using the acid is valuable for the different light condition.Methods: The sample was collected as four month of interval of time and the seed is treated with acids with different time. Results: seeds scarified with sulfuric acids for 10 min before sowing had better germination than those scarified for 5 and 15 min. Among them light qualities, red and white light had slightly promoted effect whereas blue light and dark condition had slightly negative effect on seed germination.Conclusions: In comparison to blue light and dark condition, red light and white light were promoted to percentage germination indicating the role of phytochrome in seed germination of Desmodium triflorum.

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Enhanced Microalgal Lipid Production in Internally Illuminated Airlift Photobioreactor

Marine Technology Society Journal ◽

10.4031/mtsj.53.2.4 ◽

2019 ◽

Vol 53 (2) ◽

pp. 38-45

Author(s):

Irem Deniz ◽

Zeliha Demirel ◽

Esra Imamoglu ◽

Meltem Conk Dalay

Keyword(s):

Fatty Acids ◽

Growth Rate ◽

Blue Light ◽

Lipid Content ◽

White Light ◽

Lipid Production ◽

Red Light ◽

Light Spectrum ◽

Light Supply ◽

Total Fatty Acids

AbstractInternal illumination systems are being considered for use as an alternative light supply technique in microalgal products. The main goal of the study was to analyze the roles of different light wavelengths in internally illuminated airlift photobioreactors (PBRs) providing the light energy in an efficient way for the biomass production, lipid yield, and fatty acid composition of Amphora capitellata. The maximum chlorophyll-a concentration per unit biomass (2.62 ± 0.16 mg L−1) was obtained under red light, which was only 14% higher than under blue light in internally illuminated airlift PBR, whereas low chlorophyll-a content was found under white light. Maximum specific growth rate of 0.317 day−1, which corresponded to a doubling time of 2.185 days, was obtained under red light for A. capitellata. It was found that lipid content increased with decreasing growth rate for A. capitellata. Palmitic acid (C16:0) and palmitoleic acid (C16:1) were the principal fatty acids accounting for between 31%‐33% and 31%‐32% of total fatty acids, respectively. It is important to underline that red and blue light spectrum ranges contribute to improved biomass growth, whereas white light has the potential to support lipid content of diatoms.

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Influence of red light on the expression of genes on stomatal formation in maize seedlings

Canadian Journal of Plant Science ◽

10.1139/cjps-2019-0140 ◽

2020 ◽

Vol 100 (3) ◽

pp. 296-303

Author(s):

Tie Dong Liu ◽

Xi Wen Zhang ◽

Yong Xu

Keyword(s):

Blue Light ◽

Stomatal Density ◽

Red Light ◽

Net Photosynthesis ◽

Stomatal Development ◽

Intercellular Signaling ◽

Stomatal Index ◽

Maize Seedlings ◽

Expression Levels ◽

Expression Of Genes

Red light significantly affects the expression of plant photoreceptor genes and influences stomatal development through crosstalk of the constitutive photomorphogenic 1–cryptochrome–phytochrome signaling pathway. When blue light was replaced with red light, the expression levels of ZmCry1, ZmPhyB1, ZmEPF2, and ZmEPFL9 were enhanced, whereas that of ZmCOP1 was restricted. Moreover, the expression levels of ZmSPCH and ZmMUTE were also enhanced, but they were generally lower than those under white light. Consequently, stomatal formation, which was determined by net photosynthesis, stomatal conductance, intercellular CO2 concentration, and transpiration rate, was inhibited through decreased stomatal index and stomatal density. We conclude that red light positively regulates EPFL9 in the intercellular signaling but reduces the positive regulation of blue light on COP1 and epidermal patterning factor 2 in the intracellular and intercellular signaling; therefore, though red light promotes the gene’s function on stomatal development of seedling maize, blue light maybe dominant to red light in seedling stage.

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A Transaldolase From Aquilaria Sinensis Involves in Aba-mediated Seed Germination and Root Growth

10.21203/rs.3.rs-234062/v1 ◽

2021 ◽

Author(s):

Yuqing Rong ◽

Tiezheng Li ◽

Xiao Liu ◽

Shepo Shi ◽

Xiaohui Wang ◽

...

Keyword(s):

Seed Germination ◽

Root Growth ◽

Pentose Phosphate ◽

Wild Type ◽

Aquilaria Sinensis ◽

Phenotypic Analysis ◽

Aba Metabolism ◽

Expression Of Genes ◽

Key Factor ◽

Key Enzyme

Abstract Transaldolase, the key enzyme of the pentose-phosphate pathway, plays an important role in plant growth and defense. Seed germination is a key factor that influences the cultivation of Aquilaria sinensis, the plant source of agarwood, which is widely used as a traditional medicine, perfume and incenses. However, little is known about the function of transaldolase in abscisic acid (ABA)-mediated seed germination. In the present study, the full-length AsTal1 gene was isolated and characterized from A. sinensis calli. Sublocalization analysis indicated that AsTal1 was localized in the cytoplasm. In addition, phenotypic analysis indicated that AsTal1-overexpressing Nicotiana benthamiana (OE) plants were less sensitive to ABA during seed germination and root growth than wild-type (WT) plants. Overexpression of AsTal1 regulated the expression of genes involved in ABA metabolism, biosynthesis and signal transduction under ABA treatment. In addition, expression of NbRbohA and NbRbohB was inhibited in the overexpression lines, whereas the abundance and activities of the antioxidative enzymes SOD, APX, and POD were higher in the transgenic plants than in the WT lines after ABA treatment. Taken together, our results indicated that AsTal1 is involved in the ABA response during seed germination and root growth by regulating the expression of genes involved in the ABA signaling pathway and the enzymes responsive to ROS.

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Manipulation of light spectrum can improve the performance of photosynthetic apparatus of strawberry plants growing under salt and alkalinity stress

PLoS ONE ◽

10.1371/journal.pone.0261585 ◽

2021 ◽

Vol 16 (12) ◽

pp. e0261585

Author(s):

Majid Esmaeilizadeh ◽

Mohammad Reza Malekzadeh Shamsabad ◽

Hamid Reza Roosta ◽

Piotr Dąbrowski ◽

Marcin Rapacz ◽

...

Keyword(s):

Blue Light ◽

Red Light ◽

Photosynthetic Apparatus ◽

Stress Conditions ◽

Control Treatment ◽

Light Spectrum ◽

Light Spectra ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency ◽

Metabolic Activities

Strawberry is one of the plants sensitive to salt and alkalinity stress. Light quality affects plant growth and metabolic activities. However, there is no clear answer in the literature on how light can improve the performance of the photosynthetic apparatus of this species under salt and alkalinity stress. The aim of this work was to investigate the effects of different spectra of supplemental light on strawberry (cv. Camarosa) under salt and alkalinity stress conditions. Light spectra of blue (with peak 460 nm), red (with peak 660 nm), blue/red (1:3), white/yellow (1:1) (400–700 nm) and ambient light were used as control. There were three stress treatments: control (no stress), alkalinity (40 mM NaHCO3), and salinity (80 mM NaCl). Under stress conditions, red and red/blue light had a positive effect on CO2 assimilation. In addition, blue/red light increased intrinsic water use efficiency (WUEi) under both stress conditions. Salinity and alkalinity stress decreased OJIP curves compared to the control treatment. Blue light caused an increase in its in plants under salinity stress, and red and blue/red light caused an increase in its in plants under alkalinity. Both salt and alkalinity stress caused a significant reduction in photosystem II (PSII) performance indices and quantum yield parameters. Adjustment of light spectra, especially red light, increased these parameters. It can be concluded that the adverse effects of salt and alkalinity stress on photosynthesis can be partially alleviated by changing the light spectra.

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The Physiological Response of Lettuce to Red and Blue Light Dynamics Over Different Photoperiods

Frontiers in Plant Science ◽

10.3389/fpls.2020.610174 ◽

2021 ◽

Vol 11 ◽

Author(s):

Giedrė Samuolienė ◽

Akvilė Viršilė ◽

Jurga Miliauskienė ◽

Perttu J. Haimi ◽

Kristina Laužikė ◽

...

Keyword(s):

Blue Light ◽

Physiological Response ◽

Nutritive Value ◽

Leaf Gas Exchange ◽

Soluble Sugar ◽

Soluble Sugars ◽

Red Light ◽

Antioxidant Properties ◽

Photon Flux ◽

Light Spectrum

This study aimed to evaluate the effect of dynamic red and blue light parameters on the physiological responses and key metabolites in lettuce and also the subsequent impact of varying light spectra on nutritive value. We explored the metabolic changes in carotenes, xanthophylls, soluble sugars, organic acids, and antioxidants; the response of photosynthetic indices [photosynthetic (Pr) and transpiration (Tr) rates]; and the intracellular to ambient CO2 concentration ratios (Ci/Ca) in lettuce (Lactuca sativa L. “Lobjoits Green Cos”). They were cultivated under constant (con) or parabolic (dyn) blue (B, 452 nm) and/or red (R, 662 nm) light-emitting diode (LED) photosynthetic photon flux densities (PPFDs) at 12, 16, and 20 h photoperiods, maintaining consistent daily light integrals (DLIs) for each light component in all treatments, at 2.3 and 9.2 mol m–2 per day for blue and red light, respectively. The obtained results and principal component analysis (PCA) confirmed a significant impact of the light spectrum, photoperiod, and parabolic profiles of PPFD on the physiological response of lettuce. The 16 h photoperiod resulted in significantly higher content of xanthophylls (neoxanthin, violaxanthin, lutein, and zeaxanthin) in lettuce leaves under both constant and parabolic blue light treatments (BconRdyn 16 h and BdynRdyn 16 h, respectively). Lower PPFD levels under a 20 h photoperiod (BdynRdyn 20 h) as well as higher PPFD levels under a 12 h photoperiod (BdynRdyn 12 h) had a pronounced impact on leaf gas exchange indices (Pr, Tr, Ci/Ca), xanthophylls, soluble sugar contents, and antioxidant properties of lettuce leaves. The parabolic PPFD lighting profile over a 16 h photoperiod (BdynRdyn 16 h) led to a significant decrease in Ci/Ca, which resulted in decreased Pr and Tr, compared with constant blue or red light treatments with the same photoperiod (BconRdyn and BdynRcon 16 h). Additionally, constant blue lighting produced higher α + β-carotene and anthocyanin (ARI) content and increased carotenoid to chlorophyll ratio (CRI) but decreased biomass accumulation and antioxidant activity.

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MOTHER-OF-FT-AND-TFL1 represses seed germination under far-red light by modulating phytohormone responses in Arabidopsis thaliana

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1806460115 ◽

2018 ◽

Vol 115 (33) ◽

pp. 8442-8447 ◽

Cited By ~ 20

Author(s):

Fabián E. Vaistij ◽

Thiago Barros-Galvão ◽

Adama F. Cole ◽

Alison D. Gilday ◽

Zhesi He ◽

...

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Seed Germination ◽

Signaling Pathways ◽

Red Light ◽

Dependent Manner ◽

Light Conditions ◽

Ga Signaling ◽

Expression Of Genes ◽

Genes Encoding

Seed germination in many plant species is triggered by sunlight, which is rich in the red (R) wavelength and repressed by under-the-canopy light rich in far red (FR). R:FR ratios are sensed by phytochromes to regulate levels of gibberellins (GAs) and abscisic acid (ABA), which induce and inhibit germination respectively. In this study we have discovered that, under FR light conditions, germination is repressed by MOTHER-OF-FT-AND-TFL1 (MFT) through the regulation of the ABA and GA signaling pathways. We also show that MFT gene expression is tightly regulated by light quality. Previous work has shown that under FR light conditions the transcription factor PHYOCHROME-INTERACTING-FACTOR1 (PIF1) accumulates and promotes expression of SOMNUS (SOM) that, in turn, leads to increased ABA and decreased GA levels. PIF1 also promotes expression of genes encoding ABA-INSENSITIVE5 (ABI5) and DELLA growth-repressor proteins, which act in the ABA and GA signaling pathways, respectively. Here we show that MFT gene expression is promoted by FR light through the PIF1/SOM/ABI5/DELLA pathway and is repressed by R light via the transcription factor SPATULA (SPT). Consistent with this, we also show that SPT gene expression is repressed under FR light in a PIF1-dependent manner. Furthermore, transcriptomic analyses presented in this study indicate that MFT exerts its function by promoting expression of known ABA-induced genes and repressing cell wall expansion-related genes.

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