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1.
Int J Mol Sci ; 22(19)2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34639031

RESUMO

The family of phytochrome photoreceptors contains proteins with different domain architectures and spectral properties. Knotless phytochromes are one of the three main subgroups classified by their distinct lack of the PAS domain in their photosensory core module, which is in contrast to the canonical PAS-GAF-PHY array. Despite intensive research on the ultrafast photodynamics of phytochromes, little is known about the primary kinetics in knotless phytochromes. Here, we present the ultrafast Pr ⇆ Pfr photodynamics of SynCph2, the best-known knotless phytochrome. Our results show that the excited state lifetime of Pr* (~200 ps) is similar to bacteriophytochromes, but much longer than in most canonical phytochromes. We assign the slow Pr* kinetics to relaxation processes of the chromophore-binding pocket that controls the bilin chromophore's isomerization step. The Pfr photoconversion dynamics starts with a faster excited state relaxation than in canonical phytochromes, but, despite the differences in the respective domain architectures, proceeds via similar ground state intermediate steps up to Meta-F. Based on our observations, we propose that the kinetic features and overall dynamics of the ultrafast photoreaction are determined to a great extent by the geometrical context (i.e., available space and flexibility) within the binding pocket, while the general reaction steps following the photoexcitation are most likely conserved among the red/far-red phytochromes.


Assuntos
Processos Fotoquímicos , Fitocromo/química , Fitocromo/metabolismo , Cinética , Luz , Modelos Moleculares , Fotorreceptores Microbianos/química , Fotorreceptores Microbianos/metabolismo , Conformação Proteica , Análise Espectral , Relação Estrutura-Atividade
2.
Phys Chem Chem Phys ; 23(33): 18197-18205, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34612283

RESUMO

Bacterial phytochromes are sensoric photoreceptors that transform light absorbed by the photosensor core module (PCM) to protein structural changes that eventually lead to the activation of the enzymatic output module. The underlying photoinduced reaction cascade in the PCM starts with the isomerization of the tetrapyrrole chromophore, followed by conformational relaxations, proton transfer steps, and a secondary structure transition of a peptide segment (tongue) that is essential for communicating the signal to the output module. In this work, we employed various static and time-resolved IR and resonance Raman spectroscopic techniques to study the structural and reaction dynamics of the Meta-F intermediate of both the PCM and the full-length (PCM and output module) variant of the bathy phytochrome Agp2 from Agrobacterium fabrum. In both cases, this intermediate represents a branching point of the phototransformation, since it opens an unproductive reaction channel back to the initial state and a productive pathway to the final active state, including the functional protein structural changes. It is shown that the functional quantum yield, i.e. the events of tongue refolding per absorbed photons, is lower by a factor of ca. two than the quantum yield of the primary photochemical process. However, the kinetic data derived from the spectroscopic experiments imply an increased formation of the final active state upon increasing photon flux or elevated temperature under photostationary conditions. Accordingly, the branching mechanism does not only account for the phytochrome's function as a light intensity sensor but may also modulate its temperature sensitivity.


Assuntos
Agrobacterium/metabolismo , Proteínas de Bactérias/metabolismo , Luz , Fitocromo/metabolismo , Temperatura , Tetrapirróis/metabolismo , Agrobacterium/química , Proteínas de Bactérias/química , Fitocromo/química , Tetrapirróis/química
3.
Int J Mol Sci ; 22(16)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34445714

RESUMO

Phytochromobilin (PΦB) participates in the regulation of plant growth and development as an important synthetase of photoreceptor phytochromes (phy). In addition, Arabidopsis long hypocotyl 2 (HY2) appropriately works as a key PΦB synthetase. However, whether HY2 takes part in the plant stress response signal network remains unknown. Here, we described the function of HY2 in NaCl signaling. The hy2 mutant was NaCl-insensitive, whereas HY2-overexpressing lines showed NaCl-hypersensitive phenotypes during seed germination. The exogenous NaCl induced the transcription and the protein level of HY2, which positively mediated the expression of downstream stress-related genes of RD29A, RD29B, and DREB2A. Further quantitative proteomics showed the patterns of 7391 proteins under salt stress. HY2 was then found to specifically mediate 215 differentially regulated proteins (DRPs), which, according to GO enrichment analysis, were mainly involved in ion homeostasis, flavonoid biosynthetic and metabolic pathways, hormone response (SA, JA, ABA, ethylene), the reactive oxygen species (ROS) metabolic pathway, photosynthesis, and detoxification pathways to respond to salt stress. More importantly, ANNAT1-ANNAT2-ANNAT3-ANNAT4 and GSTU19-GSTF10-RPL5A-RPL5B-AT2G32060, two protein interaction networks specifically regulated by HY2, jointly participated in the salt stress response. These results direct the pathway of HY2 participating in salt stress, and provide new insights for the plant to resist salt stress.


Assuntos
Arabidopsis/genética , Arabidopsis/metabolismo , Oxirredutases/genética , Oxirredutases/metabolismo , Secas , Germinação/fisiologia , Oxirredutases/fisiologia , Fitocromo/metabolismo , Desenvolvimento Vegetal/efeitos dos fármacos , Plantas Geneticamente Modificadas , Estresse Salino/efeitos dos fármacos , Estresse Salino/genética , Estresse Salino/fisiologia , Sementes/metabolismo , Transdução de Sinais/fisiologia , Cloreto de Sódio/metabolismo , Estresse Fisiológico/genética
4.
New Phytol ; 232(3): 1201-1211, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34289130

RESUMO

Plants monitor their surrounding ambient light environment by specialized photoreceptor proteins. Among them, phytochromes monitor red and far-red light. These molecules perceive photons, undergo a conformational change, and regulate diverse light signaling pathways, resulting in the mediation of key developmental and growth responses throughout the whole life of plants. Posttranslational modifications of the photoreceptors and their signaling partners may modify their function. For example, the regulatory role of phosphorylation has been investigated for decades by using different methodological approaches. In the past few years, a set of studies revealed that ubiquitin-like short protein molecules, called small ubiquitin-like modifiers (SUMOs) are attached reversibly to different members of phytochrome signaling pathways, including phytochrome B, the dominant receptor of red light signaling. Furthermore, SUMO attachment modifies the action of the target proteins, leading to altered light signaling and photomorphogenesis. This review summarizes recent results regarding SUMOylation of various target proteins, the regulation of their SUMOylation level, and the physiological consequences of SUMO attachment. Potential future research directions are also discussed.


Assuntos
Proteínas de Arabidopsis , Fitocromo , Proteínas de Arabidopsis/metabolismo , Luz , Transdução de Sinal Luminoso , Fitocromo/metabolismo , Fitocromo B/metabolismo , Transdução de Sinais , Sumoilação
5.
PLoS One ; 16(7): e0255232, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34314454

RESUMO

Photons during the dark period delay flowering in short-day plants (SDP). Red photons applied at night convert phytochromes to the active far-red absorbing form (Pfr), leading to inhibition of flowering. Far-red photons (greater than 700 nm) re-induce flowering when applied after a pulse of red photons during the dark period. However, far-red photons at sufficiently high intensity and duration delay flowering in sensitive species. Mechanistically, this response occurs because phytochrome-red (Pr) absorbance is not zero beyond 700 nm. We applied nighttime photons from near infrared (NIR) LEDs (peak 850 nm) over a 12 h dark period. Flowering was delayed in Glycine max and Cannabis sativa (two photosensitive species) by 3 and 12 days, respectively, as the flux of photons from NIR LEDs was increased up to 83 and 116 µmol m-2 s-1. This suggests that long wavelength photons from NIR LEDs can activate phytochromes (convert Pr to Pfr) and thus alter plant development.


Assuntos
Cannabis/crescimento & desenvolvimento , Raios Infravermelhos , Fitocromo/metabolismo , Soja/crescimento & desenvolvimento , Cannabis/metabolismo , Cannabis/efeitos da radiação , Flores/crescimento & desenvolvimento , Flores/metabolismo , Flores/efeitos da radiação , Fótons , Caules de Planta/crescimento & desenvolvimento , Caules de Planta/metabolismo , Caules de Planta/efeitos da radiação , Soja/metabolismo , Soja/efeitos da radiação
6.
Angew Chem Int Ed Engl ; 60(34): 18688-18693, 2021 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-34097335

RESUMO

Phytochrome proteins are light receptors that play a pivotal role in regulating the life cycles of plants and microorganisms. Intriguingly, while cyanobacterial phytochrome Cph1 and cyanobacteriochrome AnPixJ use the same phycocyanobilin (PCB) chromophore to absorb light, their excited-state behavior is very different. We employ multiscale calculations to rationalize the different early photoisomerization mechanisms of PCB in Cph1 and AnPixJ. We found that their electronic S1 , T1 , and S0 potential minima exhibit distinct geometric and electronic structures due to different hydrogen bond networks with the protein environment. These specific interactions influence the S1 electronic structures along the photoisomerization paths, ultimately leading to internal conversion in Cph1 but intersystem crossing in AnPixJ. This explains why the excited-state relaxation in AnPixJ is much slower (ca. 100 ns) than in Cph1 (ca. 30 ps). Further, we predict that efficient internal conversion in AnPixJ can be achieved upon protonating the carboxylic group that interacts with PCB.


Assuntos
Proteínas de Bactérias/química , Cianobactérias/química , Fotorreceptores Microbianos/química , Ficobilinas/química , Ficocianina/química , Fitocromo/química , Proteínas Quinases/química , Proteínas de Bactérias/metabolismo , Cianobactérias/metabolismo , Ligação de Hidrogênio , Estrutura Molecular , Processos Fotoquímicos , Fotorreceptores Microbianos/metabolismo , Ficobilinas/metabolismo , Ficocianina/metabolismo , Fitocromo/metabolismo , Proteínas Quinases/metabolismo , Estereoisomerismo
7.
Nat Commun ; 12(1): 3593, 2021 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-34135337

RESUMO

Photoreceptors are conserved in green algae to land plants and regulate various developmental stages. In the ocean, blue light penetrates deeper than red light, and blue-light sensing is key to adapting to marine environments. Here, a search for blue-light photoreceptors in the marine metagenome uncover a chimeric gene composed of a phytochrome and a cryptochrome (Dualchrome1, DUC1) in a prasinophyte, Pycnococcus provasolii. DUC1 detects light within the orange/far-red and blue spectra, and acts as a dual photoreceptor. Analyses of its genome reveal the possible mechanisms of light adaptation. Genes for the light-harvesting complex (LHC) are duplicated and transcriptionally regulated under monochromatic orange/blue light, suggesting P. provasolii has acquired environmental adaptability to a wide range of light spectra and intensities.


Assuntos
Clorófitas/metabolismo , Oceanos e Mares , Fotorreceptores de Plantas/metabolismo , Fitoplâncton/metabolismo , Adaptação Fisiológica/genética , Núcleo Celular/metabolismo , Clorófitas/classificação , Clorófitas/genética , Criptocromos/genética , Criptocromos/metabolismo , Evolução Molecular , Luz , Metagenoma , Fotorreceptores de Plantas/genética , Filogenia , Fitocromo/genética , Fitocromo/metabolismo , Fitoplâncton/classificação , Fitoplâncton/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Tabaco/genética , Tabaco/metabolismo , Transcrição Genética/efeitos da radiação
8.
J Mol Biol ; 433(15): 167092, 2021 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-34116122

RESUMO

Protein dynamics play a major role for the catalytic function of enzymes, the interaction of protein complexes or signal integration in regulatory proteins. In the context of multi-domain proteins involved in light-regulation of enzymatic effectors, the central role of conformational dynamics is well established. Light activation of sensory modules is followed by long-range signal transduction to different effectors; rather than domino-style structural rearrangements, a complex interplay of functional elements is required to maintain functionality. One family of such sensor-effector systems are red-light-regulated phytochromes that control diguanylate cyclases involved in cyclic-dimeric-GMP formation. Based on structural and functional studies of one prototypic family member, the central role of the coiled-coil sensor-effector linker was established. Interestingly, subfamilies with different linker lengths feature strongly varying biochemical characteristics. The dynamic interplay of the domains involved, however, is presently not understood. Here we show that the PHY domain dimer interface plays an essential role in signal integration, and that a functional coupling with the coiled-coil linker element is crucial. Chimaeras of two biochemically different family members highlight the phytochrome-spanning helical spine as an essential structural element involved in light-dependent upregulation of enzymatic turnover. However, isolated structural elements can frequently not be assigned to individual characteristics, which further emphasises the importance of global conformational dynamics. Our results provide insights into the intricate processes at play during light signal integration and transduction in these photosensory systems and thus provide additional guidelines for a more directed design of novel sensor-effector combinations with potential applications as optogenetic tools.


Assuntos
Marinobacter/metabolismo , Fitocromo/química , Fitocromo/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Cristalografia por Raios X , Proteínas de Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Marinobacter/química , Modelos Moleculares , Fósforo-Oxigênio Liases/metabolismo , Conformação Proteica , Domínios Proteicos
9.
Sci Rep ; 11(1): 7948, 2021 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-33846419

RESUMO

A plant's ability to maximize seed germination, growth, and photosynthetic productivity depends on its aptitude to sense, evaluate, and respond to the quality, quantity, and direction of the light. Among diverse colors of light possessing different wavelengths and red light shown to have a high impact on the photosynthetic and growth responses of the plants. The use of artificial light sources where the quality, intensity, and duration of exposure can be controlled would be an efficient method to increase the efficiency of the crop plants. The coherent, collimated, and monochromatic properties of laser light sources enabled as biostimulator compared to the normal light. The present study was attempted to use the potential role of the He-Ne laser as a bio-stimulator device to improve the germination and growth of brinjal and to investigate the possible interactions of plant and laser photons. A substantial enhancement was observed in germination index, germination time and seed vigor index of laser-irradiated than control groups. The enhanced germination rate was correlated with higher GA content and its biosynthetic genes whereas decreased ABA content and its catabolic genes and GA/ABA ratio were noted in laser-irradiated groups during seed germination than control groups. Further the expression of phytochrome gene transcripts, PhyA and PhyB1 were upregulated in laser-irradiated seedlings which correlate with enhanced seed germination than control. Elevated levels of primary metabolites were noted in the early stages of germination whereas modulation of secondary metabolites was observed in later growth. Consequently, significantly increased photosynthetic rate, stomatal conductance, and transpiration rate was perceived in laser-irradiated seedlings compare with control. The current study showed hormone and phytochrome-mediated mechanisms of seed germination in laser-irradiated groups along with the enhanced photosynthetic rate, primary and secondary metabolites.


Assuntos
Lasers , Reguladores de Crescimento de Plantas/farmacologia , Sementes/crescimento & desenvolvimento , Solanum melongena/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Redes e Vias Metabólicas/efeitos dos fármacos , Metabolômica , Análise Multivariada , Fotossíntese/efeitos dos fármacos , Fitocromo/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Metabolismo Secundário/efeitos dos fármacos , Plântula/efeitos dos fármacos , Sementes/efeitos dos fármacos , Solanum melongena/efeitos dos fármacos
10.
J Exp Bot ; 72(12): 4577-4589, 2021 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-33830198

RESUMO

Leaf senescence can be triggered by multiple abiotic stresses including darkness, nutrient limitation, salinity, and drought. Recently, heatwaves have been occurring more frequently, and they dramatically affect plant growth and development. However, the underlying molecular networks of heat stress-induced leaf senescence remain largely uncharacterized. Here we showed that PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and PIF5 proteins could efficiently promote heat stress-induced leaf senescence in Arabidopsis. Transcriptomic profiling analysis revealed that PIF4 and PIF5 are likely to function through multiple biological processes including hormone signaling pathways. Further, we characterized NAC019, SAG113, and IAA29 as direct transcriptional targets of PIF4 and PIF5. The transcription of NAC019, SAG113, and IAA29 changes significantly in daytime after heat treatment. In addition, we demonstrated that PIF4 and PIF5 proteins were accumulated during the recovery after heat treatment. Moreover, we showed that heat stress-induced leaf senescence is gated by the circadian clock, and plants might be more actively responsive to heat stress-induced senescence during the day. Taken together, our findings proposed important roles for PIF4 and PIF5 in mediating heat stress-induced leaf senescence, which may help to fully illustrate the molecular network of heat stress-induced leaf senescence in higher plants and facilitate the generation of heat stress-tolerant crops.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Fitocromo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Regulação da Expressão Gênica de Plantas , Resposta ao Choque Térmico , Luz , Fitocromo/metabolismo
11.
Int J Mol Sci ; 22(6)2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33808792

RESUMO

Adaptation and response to environmental changes require dynamic and fast information distribution within the plant body. If one part of a plant is exposed to stress, attacked by other organisms or exposed to any other kind of threat, the information travels to neighboring organs and even neighboring plants and activates appropriate responses. The information flow is mediated by fast-traveling small metabolites, hormones, proteins/peptides, RNAs or volatiles. Electric and hydraulic waves also participate in signal propagation. The signaling molecules move from one cell to the neighboring cell, via the plasmodesmata, through the apoplast, within the vascular tissue or-as volatiles-through the air. A threat-specific response in a systemic tissue probably requires a combination of different traveling compounds. The propagating signals must travel over long distances and multiple barriers, and the signal intensity declines with increasing distance. This requires permanent amplification processes, feedback loops and cross-talks among the different traveling molecules and probably a short-term memory, to refresh the propagation process. Recent studies show that volatiles activate defense responses in systemic tissues but also play important roles in the maintenance of the propagation of traveling signals within the plant. The distal organs can respond immediately to the systemic signals or memorize the threat information and respond faster and stronger when they are exposed again to the same or even another threat. Transmission and storage of information is accompanied by loss of specificity about the threat that activated the process. I summarize our knowledge about the proposed long-distance traveling compounds and discuss their possible connections.


Assuntos
Meio Ambiente , Fenômenos Fisiológicos Vegetais , Plantas/genética , Plantas/metabolismo , Transporte Biológico , Biomarcadores , Cálcio/metabolismo , Resistência à Doença , Fenômenos Eletrofisiológicos , Interações Hospedeiro-Patógeno , Luz , Especificidade de Órgãos , Fotossíntese , Fitocromo/metabolismo , Doenças das Plantas , Plantas/microbiologia , Plantas/efeitos da radiação , RNA de Plantas , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Compostos Orgânicos Voláteis/metabolismo
12.
Curr Opin Plant Biol ; 63: 102037, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33823333

RESUMO

Light signal perceived by the red/far-red absorbing phytochrome (phy) family of photoreceptors regulates plant growth and development throughout the life cycle. Phytochromes regulate the light-triggered physiological responses by controlling gene expression both at the transcriptional and post-transcriptional levels. Recent large-scale RNA-seq studies have demonstrated the roles of phys in altering the global transcript diversity by modulating the pre-mRNA splicing in response to light. Moreover, several phy-interacting splicing factors/regulators from different species have been identified using forward genetics and protein-protein interaction studies, which modulate the light-regulated pre-mRNA splicing. In this article, we summarize our current understanding of the role of phys in the light-mediated pre-mRNA splicing and how that contributes to the regulation of gene expression to promote photomorphogenesis.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Fitocromo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Luz , Fitocromo/metabolismo , Precursores de RNA/genética , Precursores de RNA/metabolismo , Splicing de RNA/genética
13.
FEBS J ; 288(20): 5986-6002, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33864705

RESUMO

Red/far-red light-sensing bacteriophytochrome photoreceptor (BphP) pathways play key roles in bacterial physiology and ecology. These bilin-binding proteins photoswitch between two states, Pr (red absorbing) and Pfr (far-red absorbing). The isomerization of the chromophore and the downstream structural changes result in the light signal transduction. The agricultural pathogen Xanthomonas campestris pv. campestris (Xcc) code for a single bathy-like type BphP (XccBphP), previously shown to negatively regulate several light-mediated biological processes involved in virulence. Here, we generated three different full-length variants with single amino acid changes within its GAF domain that affect the XccBphP photocycle favouring its Pr state: L193Q, L193N and D199A. While D199A recombinant protein locks XccBphP in a Pr-like state, L193Q and L193N exhibit a significant enrichment of the Pr form in thermal equilibrium. The X-ray crystal structures of the three variants were solved, resembling the wild-type protein in the Pr state. Finally, we studied the effects of altering the XccBphP photocycle on the exopolysaccharide xanthan production and stomatal aperture assays as readouts of its bacterial signalling pathway. Null-mutant complementation assays show that the photoactive Pr-favoured XccBphP variants L193Q and L193N tend to negatively regulate xanthan production in vivo. In addition, our results indicate that strains expressing these variants also promote stomatal apertures in challenged plant epidermal peels, compared to wild-type Xcc. The findings presented in this work provide new evidence on the Pr state of XccBphP as a negative regulator of the virulence-associated mechanisms by light in Xcc.


Assuntos
Arabidopsis/microbiologia , Pigmentos Biliares/metabolismo , Fitocromo/química , Fitocromo/genética , Doenças das Plantas/microbiologia , Virulência , Xanthomonas campestris/fisiologia , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Cristalografia por Raios X , Luz , Modelos Moleculares , Mutagênese Sítio-Dirigida , Mutação , Fitocromo/metabolismo
14.
Proc Natl Acad Sci U S A ; 118(12)2021 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-33727422

RESUMO

Cyanobacteriochromes (CBCRs) are small, linear tetrapyrrole (bilin)-binding photoreceptors in the phytochrome superfamily that regulate diverse light-mediated adaptive processes in cyanobacteria. More spectrally diverse than canonical red/far-red-sensing phytochromes, CBCRs were thought to be restricted to sensing visible and near UV light until recently when several subfamilies with far-red-sensing representatives (frCBCRs) were discovered. Two of these frCBCRs subfamilies have been shown to incorporate bilin precursors with larger pi-conjugated chromophores, while the third frCBCR subfamily uses the same phycocyanobilin precursor found in the bulk of the known CBCRs. To elucidate the molecular basis of far-red light perception by this third frCBCR subfamily, we determined the crystal structure of the far-red-absorbing dark state of one such frCBCR Anacy_2551g3 from Anabaena cylindrica PCC 7122 which exhibits a reversible far-red/orange photocycle. Determined by room temperature serial crystallography and cryocrystallography, the refined 2.7-Å structure reveals an unusual all-Z,syn configuration of the phycocyanobilin (PCB) chromophore that is considerably less extended than those of previously characterized red-light sensors in the phytochrome superfamily. Based on structural and spectroscopic comparisons with other bilin-binding proteins together with site-directed mutagenesis data, our studies reveal protein-chromophore interactions that are critical for the atypical bathochromic shift. Based on these analyses, we propose that far-red absorption in Anacy_2551g3 is the result of the additive effect of two distinct red-shift mechanisms involving cationic bilin lactim tautomers stabilized by a constrained all-Z,syn conformation and specific interactions with a highly conserved anionic residue.


Assuntos
Pigmentos Biliares/química , Pigmentos Biliares/metabolismo , Cianobactérias/fisiologia , Modelos Moleculares , Fitocromo/química , Fitocromo/metabolismo , Conformação Proteica , Luz , Optogenética , Relação Estrutura-Atividade , Raios Ultravioleta
15.
Plant Cell Environ ; 44(6): 1816-1829, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33715163

RESUMO

Light is one of the most important environmental factors that affects various cellular processes in plant growth and development; it is also crucial for the metabolism of carbohydrates as it provides the energy source for photosynthesis. Under extended darkness conditions, carbon starvation responses are triggered by depletion of stored energy. Although light rapidly inhibits starvation responses, the molecular mechanisms by which light signalling affects this process remain largely unknown. In this study, we showed that the Arabidopsis thaliana light signalling protein FAR-RED ELONGATED HYPOCOTYL3 (FHY3) and its homolog FAR-RED IMPAIRED RESPONSE1 (FAR1) are essential for plant survival after extended darkness treatment at both seedling and adult stages. Transmission electron microscopy analyses revealed that disruption of both FHY3 and FAR1 resulted in destruction of chloroplast envelopes and thylakoid membranes under extended darkness conditions. Furthermore, treatment with sucrose, but not glucose, completely rescued carbon starvation-induced cell death in the rosette leaves and arrested early seedling establishment in the fhy3 far1 plants. We thus concluded that the light signalling proteins FHY3 and FAR1 negatively regulate carbon starvation responses in Arabidopsis.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Carbono/metabolismo , Proteínas Nucleares/metabolismo , Fitocromo/metabolismo , Arabidopsis/citologia , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/genética , Proteínas de Ciclo Celular/genética , Morte Celular , Celulases/genética , Cloroplastos/metabolismo , Cloroplastos/patologia , Escuridão , Regulação da Expressão Gênica de Plantas , Glucose/metabolismo , Glucose/farmacologia , Mutação , Proteínas Nucleares/genética , Fitocromo/genética , Células Vegetais , Folhas de Planta/citologia , Plantas Geneticamente Modificadas , Plântula/crescimento & desenvolvimento , Plântula/fisiologia , Sacarose/metabolismo , Sacarose/farmacologia , Tilacoides/metabolismo , Tilacoides/patologia
16.
Annu Rev Plant Biol ; 72: 217-244, 2021 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-33756095

RESUMO

The perception of light signals by the phytochrome family of photoreceptors has a crucial influence on almost all aspects of growth and development throughout a plant's life cycle. The holistic regulatory networks orchestrated by phytochromes, including conformational switching, subcellular localization, direct protein-protein interactions, transcriptional and posttranscriptional regulations, and translational and posttranslational controls to promote photomorphogenesis, are highly coordinated and regulated at multiple levels. During the past decade, advances using innovative approaches have substantially broadened our understanding of the sophisticated mechanisms underlying the phytochrome-mediated light signaling pathways. This review discusses and summarizes these discoveries of the role of the modular structure of phytochromes, phytochrome-interacting proteins, and their functions; the reciprocal modulation of both positive and negative regulators in phytochrome signaling; the regulatory roles of phytochromes in transcriptional activities, alternative splicing, and translational regulation; and the kinases and E3 ligases that modulate PHYTOCHROME INTERACTING FACTORs to optimize photomorphogenesis.


Assuntos
Proteínas de Arabidopsis , Fitocromo , Proteínas de Arabidopsis/metabolismo , Transdução de Sinal Luminoso , Fitocromo/metabolismo , Transdução de Sinais , Ubiquitina-Proteína Ligases/metabolismo
17.
Photochem Photobiol Sci ; 20(3): 451-473, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33721277

RESUMO

Bacteria and fungi of the plant microbiota can be phytopathogens, parasites or symbionts that establish mutually advantageous relationships with plants. They are often rich in photoreceptors for UVA-Visible light, and in many cases, they exhibit light regulation of growth patterns, infectivity or virulence, reproductive traits, and production of pigments and of metabolites. In addition to the light-driven effects, often demonstrated via the generation of photoreceptor gene knock-outs, microbial photoreceptors can exert effects also in the dark. Interestingly, some fungi switch their attitude towards plants in dependence of illumination or dark conditions in as much as they may be symbiotic or pathogenic. This review summarizes the current knowledge about the roles of light and photoreceptors in plant-associated bacteria and fungi aiming at the identification of common traits and general working ideas. Still, reports on light-driven infection of plants are often restricted to the description of macroscopically observable phenomena, whereas detailed information on the molecular level, e.g., protein-protein interaction during signal transduction or induction mechanisms of infectivity/virulence initiation remains sparse. As it becomes apparent from still only few molecular studies, photoreceptors, often from the red- and the blue light sensitive groups interact and mutually modulate their individual effects. The topic is of great relevance, even in economic terms, referring to plant-pathogen or plant-symbionts interactions, considering the increasing usage of artificial illumination in greenhouses, the possible light-regulation of the synthesis of plant-growth stimulating substances or herbicides by certain symbionts, and the biocontrol of pests by selected fungi and bacteria in a sustainable agriculture.


Assuntos
Luz , Microbiota/efeitos da radiação , Plantas/microbiologia , Bactérias/metabolismo , Bactérias/patogenicidade , Fungos/metabolismo , Fungos/patogenicidade , Fotorreceptores Microbianos/química , Fotorreceptores Microbianos/metabolismo , Fitocromo/química , Fitocromo/metabolismo
18.
Int J Biol Macromol ; 180: 14-27, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33722620

RESUMO

Phytochrome-interacting factors (PIFs) are members of basic helix-loop-helix (bHLH) transcription factors and the primary partners of phytochromes (PHY) in light signaling. PIFs interact with the Pfr forms of phytochrome to play an important role in the pathways of response to light and temperature in plants. In this study, 30, 12, and 16 potential PIF genes were identified in Brassica napus, Brassica rapa, Brassica oleracea, respectively, which could be divided into three subgroups. The Br/Bo/BnaPIF genes are intron-rich and similar to the PIF genes in Arabidopsis. However, unlike the AtPIFs that exist in multiple alternative-splicing forms, the majority of Br/Bo/BnaPIF genes have no alternative-splicing forms. A total of 52 Br/Bo/BnaPIF proteins have both the conserved active PHYB binding (APB) and bHLH domains. The Ka/Ks ratio revealed that most BnaPIFs underwent purifying selection. A promoter analysis found that light-related, abscisic acid-related and MYB-binding sites were the most abundant in the promoters of BnaPIFs. BnaPIF genes displayed different spatiotemporal patterns of expression and were regulated by light quality, circadian rhythms, cold, heat, and vernalization. Our results are useful for understanding the biological functions of PIF proteins in rapeseed.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Brassica napus/genética , Brassica napus/metabolismo , Brassica rapa/genética , Brassica rapa/metabolismo , Luz , Filogenia , Proteínas de Plantas/genética , Estresse Fisiológico/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Sítios de Ligação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Genes de Plantas , Fitocromo/metabolismo , Proteínas de Plantas/metabolismo , Regiões Promotoras Genéticas , Ligação Proteica , Transdução de Sinais/genética , Sintenia , Transcriptoma/efeitos da radiação
19.
J Photochem Photobiol B ; 217: 112164, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33676287

RESUMO

Light or low frequency magnetic field (LF-MF) as one of the cultivation environments affects secondary metabolites (SMs) production of M. purpureus. Phytochrome (Phy) is a hybrid histidine kinase possessing dual properties of photoreceptor and kinase to sense red and far-red light. The interaction effects of LF-MF and light on SMs of M. purpureus was investigated by knocking out the Phy-like gene in M. purpureus (MpPhy) by homologous recombination. A MpPhy-deletion (ΔMpPhy) strain produced less Monascus pigments (MPs) and monacolin K (mon K) than the wild-type (WT) strain and reduced citrinin production by 78.3% on 10th day but didn't affect the biomass. These results indicated that the MpPhy gene is involved in SMs biosynthesis of M. purpureus. MPs production in WT was decreased significantly when the inoculum was exposed to white/blue/green/red light (500 Lux). But it in ΔMpPhy was no significant difference when exposed to white/red light. The colony size of ΔMpPhy was smaller on potato dextrose agar media containing 0.01% SDS. These results indicated that the deletion of MpPhy gene affected the aerial hyphae and increased sensitivity to cell membrane stress but decreased sensitivity to red light. The inoculum of both WT and ΔMpPhy was exposure to the LF-MF (50 Hz). The accumulation of WT secondary metabolites was not changed, while SMs production of ΔMpPhy was significantly enhanced under exposed to 2.0 mT LF-MF. This indicated that the decrease of SMs caused by the deletion of MpPhy gene was restored by LF-MF. It revealed that there is a crosstalk between magnetoreception and photosensitivity.


Assuntos
Luz , Monascus/metabolismo , Fitocromo/genética , Metabolismo Secundário/efeitos da radiação , Biomassa , Citrinina/biossíntese , Meios de Cultura/química , Lovastatina/biossíntese , Monascus/citologia , Monascus/crescimento & desenvolvimento , Mutagênese , Fitocromo/metabolismo , Pigmentos Biológicos/metabolismo
20.
Methods Mol Biol ; 2297: 21-31, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33656666

RESUMO

The presence of neighbor or overtopping plants is perceived by changes in light quality, which lead to several growth and developmental changes known as shade avoidance syndrome (SAS). Among them, the analysis of hypocotyl elongation is an important SAS physiological output that has been successfully used to investigate photoreceptors and downstream signaling components. Here we describe the experimental setup and growth conditions used to investigate photoreceptors and their signaling mechanisms through the analysis of hypocotyl elongation in laboratory, using simulated low R/FR ratio, low blue light, and true/deep shade conditions.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Criptocromos/metabolismo , Hipocótilo/crescimento & desenvolvimento , Fitocromo/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Hipocótilo/metabolismo , Luz , Fenótipo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Transdução de Sinais
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