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Plant Communications Sep 2020Light is the most important environmental factor affecting many aspects of plant development. In this study, we report that B-box protein 11 (BBX11) acts as a positive...
Light is the most important environmental factor affecting many aspects of plant development. In this study, we report that B-box protein 11 (BBX11) acts as a positive regulator of red light signaling. BBX11 loss-of-function mutant seedlings display significantly elongated hypocotyls under conditions of both red light and long day, whereas overexpression causes markedly shortened hypocotyls under various light states. BBX11 binds to the promoter to activate its transcription, while both BBX21 and HY5 associate with the promoter of to positively regulate its expression. Taken together, our results reveal positive feedback regulation of photomorphogenesis consisting of BBX11, BBX21, and HY5, thus substantiating a transcriptional regulatory mechanism in the response of plants to light during normal development.
Topics: Arabidopsis; Arabidopsis Proteins; Basic-Leucine Zipper Transcription Factors; Chromatin Immunoprecipitation; Electrophoretic Mobility Shift Assay; Feedback, Physiological; Gene Expression Regulation, Plant; Phototropism; Real-Time Polymerase Chain Reaction; Transcription Factors; Transcription Factors, General
PubMed: 33367254
DOI: 10.1016/j.xplc.2020.100045 -
Cell Reports Apr 2020The asymmetric distribution of auxin leads to the bending growth of hypocotyls during gravitropic and phototropic responses, but the signaling events downstream of auxin...
The asymmetric distribution of auxin leads to the bending growth of hypocotyls during gravitropic and phototropic responses, but the signaling events downstream of auxin remain unclear. Here, we identify many SAUR genes showing asymmetric expression in soybean hypocotyls during gravistimulation and then study their homologs in Arabidopsis. SAUR19 subfamily genes have asymmetric expression in Arabidopsis hypocotyls during gravitropic and phototropic responses, induced by the lateral redistribution of auxin. Both the mutation of SAUR19 subfamily genes and the ectopic expression of SAUR19 weaken these tropic responses, indicating the critical role of their asymmetric expression. The auxin-responsive transcription factor ARF7 may directly bind the SAUR19 promoter and activate SAUR19 expression asymmetrically in tropic responses. Taken together, our results reveal that a gravity- or light-triggered asymmetric auxin distribution induces the asymmetric expression of SAUR19 subfamily genes by ARF7 and ARF19 in the hypocotyls, which leads to bending growth during gravitropic and phototropic responses.
Topics: Arabidopsis; Arabidopsis Proteins; Gene Expression Regulation, Plant; Gravitropism; Hypocotyl; Phototropism; Plants, Genetically Modified; Soybean Proteins; Glycine max; Transcription Factors
PubMed: 32320660
DOI: 10.1016/j.celrep.2020.107529 -
Plant Physiology Apr 2021Plants perceive dynamic light conditions and optimize their growth and development accordingly by regulating gene expression at multiple levels. Alternative splicing...
Plants perceive dynamic light conditions and optimize their growth and development accordingly by regulating gene expression at multiple levels. Alternative splicing (AS), a widespread mechanism in eukaryotes that post-transcriptionally generates two or more messenger RNAs (mRNAs) from the same pre-mRNA, is rapidly controlled by light. However, a detailed mechanism of light-regulated AS is still not clear. In this study, we demonstrate that histone 3 lysine 36 trimethylation (H3K36me3) rapidly and differentially responds to light at specific gene loci with light-regulated intron retention (IR) of their transcripts in the moss Physcomitrella patens. However, the level of H3K36me3 following exposure to light is inversely related to that of IR events. Physcomitrella patens MORF-related gene 1 (PpMRG1), a chromatin adaptor, bound with higher affinity to H3K36me3 in light conditions than in darkness and was differentially targeted to gene loci showing light-responsive IR. Transcriptome analysis indicated that PpMRG1 functions in the regulation of light-mediated AS. Furthermore, PpMRG1 was also involved in red light-mediated phototropic responses. Our results suggest that light regulates histone methylation, which leads to alterations of AS patterns. The chromatin adaptor PpMRG1 potentially participates in light-mediated AS, revealing that chromatin-coupled regulation of pre-mRNA splicing is an important aspect of the plant's response to environmental changes.
Topics: Alternative Splicing; Bryopsida; Chromatin; Gene Expression Regulation, Plant; Introns; RNA Splicing
PubMed: 33793927
DOI: 10.1093/plphys/kiaa103 -
International Journal of Molecular... Nov 2021Light is one of the most important factors that influence plant growth and development. This study was conducted to examine how lighting direction affects plant...
Light is one of the most important factors that influence plant growth and development. This study was conducted to examine how lighting direction affects plant morphophysiology by investigating plant growth parameters, leaf anatomy, epidermal cell elongation, stomatal properties, chloroplast arrangement, and physiological changes. In closed-type plant factory units, the rooted cuttings of two chrysanthemum ( Ramat.) cultivars, 'Gaya Glory' and 'Pearl Egg', were subjected to a 10 h photoperiod with a 300 μmol∙m∙s photosynthetic photon flux density (PPFD) provided by light-emitting diodes (LEDs) from three directions relative to the plant including the top, side, and bottom. Compared to the top or bottom lighting, the side lighting greatly enhanced the plant growth, improved the leaf internal structure and chloroplast arrangement, induced small stomata with a higher density, and promoted stomatal opening, which is associated with an increased stomatal conductance and photosynthetic efficiency. It is worth noting that the side lighting significantly enhanced the induction of branching and flowering for both cultivars., The plants grown with side lighting consistently exhibited the greatest physiological performance. We conclude that the lighting direction had a profound effect on the morphophysiological characteristics of chrysanthemum, and that side lighting dramatically promoted their growth and development, especially in their branching and flowering.
Topics: Chrysanthemum; Lighting; Photoperiod; Photosynthesis; Plant Development; Plant Leaves
PubMed: 34769450
DOI: 10.3390/ijms222112019 -
International Journal of Environmental... May 2020The purpose of this study was to determine the effects that different container conditions have on seedling growth. Under greenhouse cultivation, there were no...
The purpose of this study was to determine the effects that different container conditions have on seedling growth. Under greenhouse cultivation, there were no statistical differences observed in plant height and the number of branches; however, significant differences in root collar diameter and root status were observed. In control container growth conditions, the roots grew in an abnormal spiral shape, while in negative phototropism container growth conditions the roots grew in a vertical shape. In outdoor cultivation, seedlings in various container growth conditions showed significant differences. The seedlings that were grown in negative phototropism container growth conditions showed the greatest increases in height, number of branches, root collar diameter, and root growth. This study determined that seedling roots in negative phototropism container growth conditions grew vertically, thus displaying successful rooting when they were transplanted outdoors. This resulted in favorable measurements in height, number of branches, root collar diameter, and root growth.
Topics: Pinus; Plant Roots; Seedlings
PubMed: 32438764
DOI: 10.3390/ijerph17103565 -
Nature Communications Feb 2024Crack formation observed across diverse fields like geology, nanotechnology, arts, structural engineering or surface science, is a chaotic and undesirable phenomenon,...
Crack formation observed across diverse fields like geology, nanotechnology, arts, structural engineering or surface science, is a chaotic and undesirable phenomenon, resulting in random patterns of cracks generally leading to material failure. Limiting the formation of cracks or "programming" the path of cracks is a great technological challenge since it holds promise to enhance material durability or even to develop low cost patterning methods. Drawing inspiration from negative phototropism in plants, we demonstrate the capability to organize, guide, replicate, or arrest crack propagation in colloidal films through remote light manipulation. The key consists in using plasmonic photothermal absorbers to generate "virtual" defects enabling controlled deviation of cracks. We engineer a dip-coating process coupled with selective light irradiation enabling simultaneous deposition and light-directed crack patterning. This approach represents a rare example of a robust self-assembly process with long-range order that can be programmed in both space and time.
PubMed: 38326305
DOI: 10.1038/s41467-024-45365-1 -
American Journal of Botany Nov 2019Plants synthesize information from multiple environmental stimuli when determining their direction of growth. Gravity, being ubiquitous on Earth, plays a major role in...
PREMISE
Plants synthesize information from multiple environmental stimuli when determining their direction of growth. Gravity, being ubiquitous on Earth, plays a major role in determining the direction of growth and overall architecture of the plant. Here, we utilized the microgravity environment on board the International Space Station (ISS) to identify genes involved influencing growth and development of phototropically stimulated seedlings of Arabidopsis thaliana.
METHODS
Seedlings were grown on the ISS, and RNA was extracted from 7 samples (pools of 10-15 plants) grown in microgravity (μg) or Earth gravity conditions (1-g). Transcriptomic analyses via RNA sequencing (RNA-seq) of differential gene expression was performed using the HISAT2-Stringtie-DESeq2 RNASeq pipeline. Differentially expressed genes were further characterized by using Pathway Analysis and enrichment for Gene Ontology classifications.
RESULTS
For 296 genes that were found significantly differentially expressed between plants in microgravity compared to 1-g controls, Pathway Analysis identified eight molecular pathways that were significantly affected by reduced gravity conditions. Specifically, light-associated pathways (e.g., photosynthesis-antenna proteins, photosynthesis, porphyrin, and chlorophyll metabolism) were significantly downregulated in microgravity.
CONCLUSIONS
Gene expression in A. thaliana seedlings grown in microgravity was significantly altered compared to that of the 1-g control. Understanding how plants grow in conditions of microgravity not only aids in our understanding of how plants grow and respond to the environment but will also help to efficiently grow plants during long-range space missions.
Topics: Arabidopsis; Arabidopsis Proteins; Seedlings; Space Flight; Weightlessness
PubMed: 31709515
DOI: 10.1002/ajb2.1384 -
Scientific Reports Sep 2019Carotenoid production in some non-phototropic bacteria occurs in a light-dependent manner to protect cells from photo-oxidants. Knowledge regarding the transcriptional...
Carotenoid production in some non-phototropic bacteria occurs in a light-dependent manner to protect cells from photo-oxidants. Knowledge regarding the transcriptional regulator involved in the light-dependent production of carotenoids of non-phototrophic bacteria has been mainly confined to coenzyme B-based photo-sensitive regulator CarH/LitR family proteins belonging to a MerR family transcriptional regulator. In this study, we found that bacteria belonging to Micrococcales and Corynebacteriales exhibit light-dependent carotenoid-like pigment production including an amino acid-producer Corynebacterium glutamicum AJ1511. CrtR is a putative MarR family transcriptional regulator located in the divergent region of a carotenoid biosynthesis gene cluster in the genome of those bacteria. A null mutant for crtR of C. glutamicum AJ1511 exhibited constitutive production of carotenoids independent of light. A complemented strain of the crtR mutant produced carotenoids in a light-dependent manner. Transcriptional analysis revealed that the expression of carotenoid biosynthesis genes is regulated in a light-dependent manner in the wild type, while the transcription was upregulated in the crtR mutant irrespective of light. In vitro experiments demonstrated that a recombinant CrtR protein binds to the specific sequences within the intergenic region of crtR and crtE, which corresponds to -58 to -7 for crtE, and +26 to -28 for crtR with respect to the transcriptional start site, and serves as a repressor for crtE transcription directed by RNA polymerase containing SigA. Taken together, the results indicate that CrtR light-dependently controls the expression of the carotenoid gene cluster in C. glutamicum and probably closely related Actinobacteria.
Topics: Amino Acid Sequence; Bacterial Proteins; Base Sequence; Carotenoids; Corynebacterium glutamicum; Gene Expression Regulation, Bacterial; Light; Multigene Family; Promoter Regions, Genetic; Reverse Transcriptase Polymerase Chain Reaction; Transcription Initiation Site; Transcription, Genetic
PubMed: 31511549
DOI: 10.1038/s41598-019-49384-7 -
The Plant Journal : For Cell and... Dec 2020In dense canopy, a reduction in red to far-red (R/FR) light ratio triggers shade avoidance responses (SARs) in Arabidopsis thaliana, a shade avoiding plant. Two...
In dense canopy, a reduction in red to far-red (R/FR) light ratio triggers shade avoidance responses (SARs) in Arabidopsis thaliana, a shade avoiding plant. Two red/far-red (R/FR) light photoreceptors, PHYB and PHYA, were reported to be key negative regulators of the SARs. PHYB represses the SARs under normal light conditions; however, the role of PHYA in the SARs remains elusive. We set up two shade conditions: Shade and strong Shade (s-Shade) with different R/FR ratios (0.7 and 0.1), which allowed us to observe phenotypes dominated by PHYB- and PHYA-mediated pathway, respectively. By comparing the hypocotyl growth under these two conditions with time, we found PHYA was predominantly activated in the s-Shade after prolonged shade treatment. We further showed that under s-Shade, PHYA inhibits hypocotyl elongation partially through repressing the brassinosteroid (BR) pathway. COP1 and PIF4,5 act downstream of PHYA. After prolonged shade treatment, the nuclear localization of COP1 was reduced, while the PIF4 protein level was much lower in the s-Shade than that in Shade. Both changes occurred in a PHYA-dependent manner. We propose that under deep canopy, the R/FR ratio is extremely low, which promotes the nuclear accumulation of PHYA. Activated PHYA reduces COP1 nuclear speckle, which may lead to changes of downstream targets, such as PIF4,5 and HY5. Together, these proteins regulate the BR pathway through modulating BES1/BZR1 and the expression of BR biosynthesis and BR target genes.
Topics: Arabidopsis; Arabidopsis Proteins; Brassinosteroids; Darkness; Gene Expression Regulation, Plant; Hypocotyl; Metabolic Networks and Pathways; Phototropism; Phytochrome A; Phytochrome B; Ubiquitin-Protein Ligases
PubMed: 33037720
DOI: 10.1111/tpj.15018 -
Animals : An Open Access Journal From... May 2022Bacterial symbionts in marine sponges play a decisive role in the biological and ecological functioning of their hosts. Although this topic has been the focus of...
Bacterial symbionts in marine sponges play a decisive role in the biological and ecological functioning of their hosts. Although this topic has been the focus of numerous studies, data from experiments under controlled conditions are rare. To analyze the ongoing metabolic processes, we investigated the symbiosis of the sponge specific cyanobacterium and its sponge host under varying light conditions in a defined aquarium setting for 68 days. Sponge clonal pieces were kept at four different light intensities, ranging from no light to higher intensities that were assumed to trigger light stress. Growth as a measure of host performance and photosynthetic yield as a proxy of symbiont photosynthetic activity were measured throughout the experiment. The lack of light prevented sponge growth and induced the expulsion of all cyanobacteria and related pigments by the end of the experiment. Higher light conditions allowed rapid sponge growth and high cyanobacteria densities. In addition, photosynthetically active radiation above a certain level triggered an increase in cyanobacteria's lutein levels, a UV absorbing protein, thus protecting itself and the host's cells from UV radiation damage. Thus, seems to benefit strongly from hosting the cyanbacterium and the relationship should be considered obligatory mutualistic.
PubMed: 35625129
DOI: 10.3390/ani12101283