scholarly journals PCH1 integrates circadian and light-signaling pathways to control photoperiod-responsive growth in Arabidopsis

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
He Huang ◽  
Chan Yul Yoo ◽  
Rebecca Bindbeutel ◽  
Jessica Goldsworthy ◽  
Allison Tielking ◽  
...  
Keyword(s):  
Light Exposure ◽  
Red Light ◽  
Constitutive Expression ◽  
Day Length ◽  
Light Signaling ◽  
Dependent Manner ◽  
Phytochrome B ◽  
Necessary And Sufficient ◽  
New Protein ◽  
Short Days

Plants react to seasonal change in day length through altering physiology and development. Factors that function to harmonize growth with photoperiod are poorly understood. Here we characterize a new protein that associates with both circadian clock and photoreceptor components, named PHOTOPERIODIC CONTROL OF HYPOCOTYL1 (PCH1). pch1 seedlings have overly elongated hypocotyls specifically under short days while constitutive expression of PCH1 shortens hypocotyls independent of day length. PCH1 peaks at dusk, binds phytochrome B (phyB) in a red light-dependent manner, and co-localizes with phyB into photobodies. PCH1 is necessary and sufficient to promote the biogenesis of large photobodies to maintain an active phyB pool after light exposure, potentiating red-light signaling and prolonging memory of prior illumination. Manipulating PCH1 alters PHYTOCHROME INTERACTING FACTOR 4 levels and regulates light-responsive gene expression. Thus, PCH1 is a new factor that regulates photoperiod-responsive growth by integrating the clock with light perception pathways through modulating daily phyB-signaling.

scholarly journals SUMOylation of phytochrome-B negatively regulates light-induced signaling in Arabidopsis thaliana

2015 ◽  
Vol 112 (35) ◽  
pp. 11108-11113 ◽  
Author(s):  
Ari Sadanandom ◽  
Éva Ádám ◽  
Beatriz Orosa ◽  
András Viczián ◽  
Cornelia Klose ◽  
...  
Keyword(s):  
Molecular Level ◽  
Expression Patterns ◽  
Red Light ◽  
Regulatory Proteins ◽  
Light Signaling ◽  
Phytochrome B ◽  
Sumo Proteases ◽  
C Terminus

The red/far red light absorbing photoreceptor phytochrome-B (phyB) cycles between the biologically inactive (Pr, λmax, 660 nm) and active (Pfr; λmax, 730 nm) forms and functions as a light quality and quantity controlled switch to regulate photomorphogenesis in Arabidopsis. At the molecular level, phyB interacts in a conformation-dependent fashion with a battery of downstream regulatory proteins, including PHYTOCHROME INTERACTING FACTOR transcription factors, and by modulating their activity/abundance, it alters expression patterns of genes underlying photomorphogenesis. Here we report that the small ubiquitin-like modifier (SUMO) is conjugated (SUMOylation) to the C terminus of phyB; the accumulation of SUMOylated phyB is enhanced by red light and displays a diurnal pattern in plants grown under light/dark cycles. Our data demonstrate that (i) transgenic plants expressing the mutant phyBLys996Arg-YFP photoreceptor are hypersensitive to red light, (ii) light-induced SUMOylation of the mutant phyB is drastically decreased compared with phyB-YFP, and (iii) SUMOylation of phyB inhibits binding of PHYTOCHROME INTERACTING FACTOR 5 to phyB Pfr. In addition, we show that OVERLY TOLERANT TO SALT 1 (OTS1) de-SUMOylates phyB in vitro, it interacts with phyB in vivo, and the ots1/ots2 mutant is hyposensitive to red light. Taken together, we conclude that SUMOylation of phyB negatively regulates light signaling and it is mediated, at least partly, by the action of OTS SUMO proteases.

scholarly journals Mismatched light and temperature cues disrupt locomotion and energetics via thyroid-dependent mechanisms

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Amélie Le Roy ◽  
Frank Seebacher
Keyword(s):  
Oxygen Consumption ◽  
Thyroid Hormone ◽  
Swimming Performance ◽  
Day Length ◽  
Seasonal Temperature ◽  
Dependent Manner ◽  
Atp Production ◽  
Oxidation Rates ◽  
Mitochondrial Efficiency ◽  
Short Days

Abstract Animals integrate information from different environmental cues to maintain performance across environmental gradients. Increasing average temperature and variability induced by climate change can lead to mismatches between seasonal cues. We used mosquitofish (Gambusia holbrooki) to test the hypotheses that mismatches between seasonal temperature and light regimes (short days and warm temperature and vice versa) decrease swimming performance, metabolic rates and mitochondrial efficiency and that the responses to light and temperature are mediated by thyroid hormone. We show that day length influenced thermal acclimation of swimming performance through thyroid-dependent mechanisms. Oxygen consumption rates were influenced by acclimation temperature and thyroid hormone. Mitochondrial substrate oxidation rates (state three rates) were modified by the interaction between temperature and day length, and mitochondrial efficiency (P/O ratios) increased with warm acclimation. Using P/O ratios to calibrate metabolic (oxygen consumption) scope showed that oxygen consumption did not predict adenosine triphosphate (ATP) production. Unlike oxygen consumption, ATP production was influenced by day length in a thyroid-dependent manner. Our data indicate that oxygen consumption alone should not be used as a predictor of ATP production. Overall, the effects of thyroid hormone on locomotion and energetics were reversed by mismatches such as warm temperatures on short days. We predict that mid to high latitudes in North America and Asia will be particularly affected by mismatches as a result of high seasonality and predicted warming over the next 50 years.

scholarly journals EARLY FLOWERING 3 and Photoperiod Sensing in Brachypodium distachyon

2022 ◽  
Vol 12 ◽  
Author(s):  
Frédéric Bouché ◽  
Daniel P. Woods ◽  
Julie Linden ◽  
Weiya Li ◽  
Kevin S. Mayer ◽  
...  
Keyword(s):  
Clock Genes ◽  
Brachypodium Distachyon ◽  
Expression Patterns ◽  
Marker Gene ◽  
Red Light ◽  
Early Flowering ◽  
Day Length ◽  
Wild Type ◽  
Complex Protein ◽  
Short Days

The proper timing of flowering, which is key to maximize reproductive success and yield, relies in many plant species on the coordination between environmental cues and endogenous developmental programs. The perception of changes in day length is one of the most reliable cues of seasonal change, and this involves the interplay between the sensing of light signals and the circadian clock. Here, we describe a Brachypodium distachyon mutant allele of the evening complex protein EARLY FLOWERING 3 (ELF3). We show that the elf3 mutant flowers more rapidly than wild type plants in short days as well as under longer photoperiods but, in very long (20 h) days, flowering is equally rapid in elf3 and wild type. Furthermore, flowering in the elf3 mutant is still sensitive to vernalization, but not to ambient temperature changes. Molecular analyses revealed that the expression of a short-day marker gene is suppressed in elf3 grown in short days, and the expression patterns of clock genes and flowering time regulators are altered. We also explored the mechanisms of photoperiodic perception in temperate grasses by exposing B. distachyon plants grown under a 12 h photoperiod to a daily night break consisting of a mixture of red and far-red light. We showed that 2 h breaks are sufficient to accelerate flowering in B. distachyon under non-inductive photoperiods and that this acceleration of flowering is mediated by red light. Finally, we discuss advances and perspectives for research on the perception of photoperiod in temperate grasses.

scholarly journals Impact of Light at Night Is Phase Dependent: A Study on Migratory Redheaded Bunting (Emberiza bruniceps)

2021 ◽  
Vol 9 ◽  
Author(s):  
Jayant Kumar ◽  
Shalie Malik ◽  
Sanjay Kumar Bhardwaj ◽  
Sangeeta Rani
Keyword(s):  
Light Exposure ◽  
Differential Sensitivity ◽  
Day Length ◽  
Dependent Manner ◽  
Light At Night ◽  
Late Night ◽  
Early Migration ◽  
Migratory Songbird ◽  
Temperature Rhythms ◽  
Intense Activity

Artificial light at night (LAN) alters the physiology and behavior of an organism; however, very little is known about phase-dependent effects of LAN, particularly, in night migratory songbirds. Therefore, in this study, we investigated whether the effects of LAN on daily activity and photoperiodic responses in the Palearctic Indian migratory songbird, redheaded buntings (Emberiza bruniceps), is dependent on the different phases of the night. Male buntings maintained under short photoperiod (8L:16D; L = 100 lux, D < 0.1 lux) in individual activity cages were exposed to LAN (2 lux) for 6 weeks either in 4 h bin given at the different phases of 16 h night (early, mid, or late at ZT 08–12, ZT 14–18, or ZT 20–24, respectively; n = 9 each group) or throughout 16 h night (all night light, n = 6, ZT 08–24, the time of lights ON was considered as Zeitgeber time 0, ZT 0). A group (n = 6) with no LAN served as control. The results showed that LAN at the different phases of night induced differential effects as shown by an intense activity during the night, altered melatonin and temperature rhythms, and showed an increase in body mass and body fattening, food intake, and gonadal size. Midnight light exposure has a greater impact on migration and reproduction linked phenotypes, which is similar to the ones that received light throughout the night. The highlights of this study are that (i) LAN impacts day-night activity behavior, (ii) its continuity with the day alters the perception of day length, (iii) birds showed differential sensitivity to LAN in a phase-dependent manner, (iv) the direction of placing LAN affects the daily responses, e.g., LAN in the early night was “accepted” as extended dusk but the late night was considered as early dawn, and (v) midnight LAN was most effective and induced similar responses as continuous LAN. Overall, LAN induces long day responses in short days and shows differential sensitivity of the different phases of the night toward the light. This information may be valuable in adopting a part-night lighting approach to help reduce the physiological burden, such as early migration and reproduction, of artificial lighting on the nocturnal migrants.

scholarly journals Photodynamic Therapy for Acinetobacter baumannii Burn Infections in Mice

2009 ◽  
Vol 53 (9) ◽  
pp. 3929-3934 ◽  
Author(s):  
Tianhong Dai ◽  
George P. Tegos ◽  
Zongshun Lu ◽  
Liyi Huang ◽  
Timur Zhiyentayev ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Acinetobacter Baumannii ◽  
Light Exposure ◽  
Middle Eastern ◽  
Red Light ◽  
Dorsal Surface ◽  
Multidrug Resistant ◽  
Dependent Manner ◽  
Chronic Infections ◽  
Bacterial Luminescence

ABSTRACT Multidrug-resistant Acinetobacter baumannii infections represent a growing problem, especially in traumatic wounds and burns suffered by military personnel injured in Middle Eastern conflicts. Effective treatment with traditional antibiotics can be extremely difficult, and new antimicrobial approaches are being investigated. One of these alternatives to antimicrobials could be the combination of nontoxic photosensitizers (PSs) and visible light, known as photodynamic therapy (PDT). We report on the establishment of a new mouse model of full-thickness thermal burns infected with a bioluminescent derivative of a clinical Iraqi isolate of A. baumannii and its PDT treatment by topical application of a PS produced by the covalent conjugation of chlorin(e6) to polyethylenimine, followed by illumination of the burn surface with red light. Application of 108 A. baumannii cells to the surface of 10-s burns made on the dorsal surface of shaved female BALB/c mice led to chronic infections that lasted, on average, 22 days and that were characterized by a remarkably stable bacterial bioluminescence. PDT carried out on day 0 soon after application of the bacteria gave over 3 log units of loss of bacterial luminescence in a light exposure-dependent manner, while PDT carried out on day 1 and day 2 gave an approximately 1.7-log reduction. The application of PS dissolved in 10% or 20% dimethyl sulfoxide without light gave only a modest reduction in the bacterial luminescence from mouse burns. Some bacterial regrowth in the treated burn was observed but was generally modest. It was also found that PDT did not lead to the inhibition of wound healing. The data suggest that PDT may be an effective new treatment for multidrug-resistant localized A. baumannii infections.

The homeodomain-leucine zipper ATHB23, a phytochrome B-interacting protein, is important for phytochrome B-mediated red light signaling

2013 ◽  
Vol 150 (2) ◽  
pp. 308-320 ◽  
Author(s):  
Hyunmo Choi ◽  
Suyeong Jeong ◽  
Dong Su Kim ◽  
Hyung Jin Na ◽  
Jong Sang Ryu ◽  
...  
Keyword(s):  
Leucine Zipper ◽  
Red Light ◽  
Light Signaling ◽  
Phytochrome B ◽  
Interacting Protein

scholarly journals BBX4, a phyB-interacting and modulated regulator, directly interacts with PIF3 to fine tune red light-mediated photomorphogenesis

2019 ◽  
Vol 116 (51) ◽  
pp. 26049-26056 ◽  
Author(s):  
Yueqin Heng ◽  
Yan Jiang ◽  
Xianhai Zhao ◽  
Hua Zhou ◽  
Xuncheng Wang ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Red Light ◽  
Plant Cells ◽  
26S Proteasome ◽  
Light Signaling ◽  
Physical Interaction ◽  
Phytochrome B ◽  
Molecular Events ◽  
Light Signals ◽  
Fine Tune

Phytochrome B (phyB) absorbs red light signals and subsequently initiates a set of molecular events in plant cells to promote photomorphogenesis. Here we show that phyB directly interacts with B-BOX CONTAINING PROTEIN 4 (BBX4), a positive regulator of red light signaling, and positively controls its abundance in red light. BBX4 associates with PHYTOCHROME INTERACTING FACTOR 3 (PIF3) and represses PIF3 transcriptional activation activity and PIF3-controlled gene expression. The degradation of BBX4 in darkness is dependent on CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) and the 26S proteasome system. Collectively, BBX4 acts as a key component of the phyB-PIF3–mediated signaling module and fine tunes the red light action. phyB promotes the accumulation of BBX4, which in turn serves to repress PIF3 action through direct physical interaction to promote photomorphogenic development in red light.

scholarly journals Inhibition of arabidopsis hypocotyl elongation by jasmonates is enhanced under red light in phytochrome B dependent manner

2012 ◽  
Vol 126 (1) ◽  
pp. 161-168 ◽  
Author(s):  
Jing Chen ◽  
Kohei Sonobe ◽  
Narihito Ogawa ◽  
Shinji Masuda ◽  
Akira Nagatani ◽  
...  
Keyword(s):  
Red Light ◽  
Hypocotyl Elongation ◽  
Dependent Manner ◽  
Phytochrome B
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