Summary
Chromatin modifications are known to affect flowering time in plants, but little is known about how these modifications regulate flowering time in response to environmental signals like ...photoperiod. In Arabidopsis thaliana, HDC1, a conserved subunit of the RPD3‐like histone deacetylase (HDAC) complex, was previously reported to regulate flowering time via the same mechanism as does the HDAC HDA6. Here, we demonstrate that HDC1, SNLs and MSI1 are shared subunits of the HDA6 and HDA19 HDAC complexes. While the late‐flowering phenotype of the hda6 mutant is independent of photoperiod, the hda19, hdc1 and snl2/3/4 mutants flower later than or at a similar time to the wild‐type in long‐day conditions but flower earlier than the wild‐type in short‐day conditions. Our genome‐wide analyses indicate that the effect of hdc1 on histone acetylation and transcription is comparable with that of hda19 but is different from that of hda6. Especially, we demonstrate that the HDA19 complex directly regulates the expression of two flowering repressor genes related to the gibberellin signaling pathway. Thus, the study reveals a photoperiod‐dependent role of the HDA19 HDAC complex in the regulation of flowering time.
Significance Statement
The study indicates that the HDA19 histone deacetylase (HDAC) complex promotes flowering in long‐day conditions and suppresses flowering in short‐day conditions, thus revealing a photoperiod‐dependent role of the complex in the regulation of flowering time. The study demonstrates that the photoperiod‐dependent regulation of flowering time is at least partially attributed to the HDA19 HDAC complex.
Hyperspectral image (HSI) denoising is an essential preprocess step to improve the performance of subsequent applications. For HSI, there is much global and local redundancy and correlation (RAC) in ...spatial/spectral dimensions. In addition, denoising performance can be improved greatly if RAC is utilized efficiently in the denoising process. In this paper, an HSI denoising method is proposed by jointly utilizing the global and local RAC in spatial/spectral domains. First, sparse coding is exploited to model the global RAC in the spatial domain and local RAC in the spectral domain. Noise can be removed by sparse approximated data with learned dictionary. At this stage, only local RAC in the spectral domain is employed. It will cause spectral distortion. To compensate the shortcoming of local spectral RAC, low-rank constraint is used to deal with the global RAC in the spectral domain. Different hyperspectral data sets are used to test the performance of the proposed method. The denoising results by the proposed method are superior to results obtained by other state-of-the-art hyperspectral denoising methods.
DNA methylation is an epigenetic modification required for transposable element (TE) silencing, genome stability, and genomic imprinting. Although DNA methylation has been intensively studied, the ...dynamic nature of methylation among different species has just begun to be understood. Here we summarize the recent progress in research on the wide variation of DNA methylation in different plants, organs, tissues, and cells; dynamic changes of methylation are also reported during plant growth and development as well as changes in response to environmental stresses. Overall DNA methylation is quite diverse among species, and it occurs in CG, CHG, and CHH (H = A, C, or T) contexts of genes and TEs in angiosperms. Moderately expressed genes are most likely methylated in gene bodies. Methylation levels decrease significantly just upstream of the transcription start site and around transcription termination sites; its levels in the promoter are inversely correlated with the expression of some genes in plants. Methylation can be altered by different environmental stimuli such as pathogens and abiotic stresses. It is likely that methylation existed in the common eukaryotic ancestor before fungi, plants and animals diverged during evolution. In summary, DNA methylation patterns in angiosperms are complex, dynamic, and an integral part of genome diversity after millions of years of evolution.
Hyperspectral image super-resolution by fusing high-resolution multispectral image (HR-MSI) and low-resolution hyperspectral image (LR-HSI) aims at reconstructing high resolution spatial-spectral ...information of the scene. Existing methods mostly based on spectral unmixing and sparse representation are often developed from a low-level vision task perspective, they cannot sufficiently make use of the spatial and spectral priors available from higher-level analysis. To this issue, this paper proposes a novel HSI super-resolution method that fully considers the spatial/spectral subspace low-rank relationships between available HR-MSI/LR-HSI and latent HSI. Specifically, it relies on a new subspace clustering method named "structured sparse low-rank representation" (SSLRR), to represent the data samples as linear combinations of the bases in a given dictionary, where the sparse structure is induced by low-rank factorization for the affinity matrix. Then we exploit the proposed SSLRR model to learn the SSLRR along spatial/spectral domain from the MSI/HSI inputs. By using the learned spatial and spectral low-rank structures, we formulate the proposed HSI super-resolution model as a variational optimization problem, which can be readily solved by the ADMM algorithm. Compared with state-of-the-art hyperspectral super-resolution methods, the proposed method shows better performance on three benchmark datasets in terms of both visual and quantitative evaluation.
Plants in nature are constantly exposed to organisms that touch them and wound them.A highly conserved response to these stimuli is a rapid collapse of membrane potential (i.e. a decrease of ...electrical field strength across membranes). This can be coupled to the production and/or action of jasmonate or ethylene. Here, the various types of electrical signals in plants are discussed in the context of hormone responses. Genetic approaches are revealing genes involved in wound-induced electrical signalling. These include clade 3 GLUTAMATE RECEPTOR-LIKE (GLR) genes, Arabidopsis H⁺-ATPases (AHAs), RESPIRATORY BURST OXIDASE HOMOLOGUEs (RBOHs), and genes that determine cell wall properties. We briefly review touch- and wound-induced increases in cytosolic Ca2+ concentrations and their temporal relationship to electrical activities. We then look at the questions that need addressing to link mechanostimulation and wound-induced electrical activity to hormone responses. Utilizing recently published results, we also present a hypothesis for wound-response leaf-to-leaf electrical signalling. This model is based on rapid electro-osmotic coupling between the phloem and xylem. The model suggests that the depolarization of membranes within the vascular matrix triggered by physical stimuli and/or chemical elicitors is linked to changes in phloem turgor and that this plays vital roles in leaf-to-leaf electrical signal propagation.
Nanozymes, a type of nanomaterials that function similarly to natural enzymes, receive extensive attention in biomedical fields. However, the widespread applications of nanozymes are greatly plagued ...by their unsatisfactory enzyme‐mimicking activity. Localized surface plasmon resonance (LSPR), a nanoscale physical phenomenon described as the collective oscillation of surface free electrons in plasmonic nanoparticles under light irradiation, offers a robust universal paradigm to boost the catalytic performance of nanozymes. Plasmonic nanozymes (PNzymes) with elevated enzyme‐mimicking activity by leveraging LSPR, emerge and provide unprecedented opportunities for biocatalysis. In this review, the physical mechanisms behind PNzymes are thoroughly revealed including near‐field enhancement, hot carriers, and the photothermal effect. The rational design and applications of PNzymes in biosensing, cancer therapy, and bacterial infections elimination are systematically introduced. Current challenges and further perspectives of PNzymes are also summarized and discussed to stimulate their clinical translation. It is hoped that this review can attract more researchers to further advance the promising field of PNzymes and open up a new avenue for optimizing the enzyme‐mimicking activity of nanozymes to create superior nanocatalysts for biomedical applications.
Plasmonic nanozymes (PNzymes), the “beautiful and incredible” encounter between nanozymes and localized surface plasmon resonance effects, and their catalytic mechanisms, bioapplications as well as current challenges and further perspectives are systematically summarized and discussed. It is anticipated that this review will provide new insights into the design of powerful nanocatalysts for biomedical applications.
Increasing seed oil content is one of the most important breeding goals for soybean due to a high global demand for edible vegetable oil. However, genetic improvement of seed oil content has been ...difficult in soybean because of the complexity of oil metabolism. Determining the major variants and molecular mechanisms conferring oil accumulation is critical for substantial oil enhancement in soybean and other oilseed crops. In this study, we evaluated the seed oil contents of 219 diverse soybean accessions across six different environments and dissected the underlying mechanism using a high-resolution genome-wide association study (GWAS). An environmentally stable quantitative trait locus (QTL), GqOil20, significantly associated with oil content was identified, accounting for 23.70% of the total phenotypic variance of seed oil across multiple environments. Haplotype and expression analyses indicate that an oleosin protein-encoding gene (GmOLEO1), colocated with a leading single nucleotide polymorphism (SNP) from the GWAS, was significantly correlated with seed oil content. GmOLEO1 is predominantly expressed during seed maturation, and GmOLEO1 is localized to accumulated oil bodies (OBs) in maturing seeds. Overexpression of GmOLEO1 significantly enriched smaller OBs and increased seed oil content by 10.6% compared with those of control seeds. A time-course transcriptomics analysis between transgenic and control soybeans indicated that GmOLEO1 positively enhanced oil accumulation by affecting triacylglycerol metabolism. Our results also showed that strong artificial selection had occurred in the promoter region of GmOLEO1, which resulted in its high expression in cultivated soybean relative to wild soybean, leading to increased seed oil accumulation. The GmOLEO1 locus may serve as a direct target for both genetic engineering and selection for soybean oil improvement.
Copper is equipped with excellent electrical and thermal properties. However, its poor mechanical properties and poor high-temperature stability prevent its extensive used in structural materials. ...Therefore, establishing an effective strengthening method that enables copper to increase its strength and high-temperature tolerance can promote wide-ranging copper applications. An effective method is the addition of ceramic particles as a reinforcement phase to improve the mechanical properties of copper. The preparation processes of several ceramic particles reinforced copper-based composites are discussed in this paper, including three powder metallurgy processes as mechanical alloying, internal oxidation, and wet chemistry, as well as friction stir processing, reactive spray deposition, and liquidus in situ reaction. The effects of each process on the mechanical properties of copper-matrix composites are introduced.
•Preparation of copper-matrix composites reinforced by the second phase is reviewed.•Mechanical alloying has the characteristics of simple process and low production cost.•Ti, La, and so on in CMCs is of great significance for improving the stability and strength of copper.•Friction stir process is mainly used to modify copper surface.
“Regiodivergent catalysis” is discussed as a class of highly selective reactions of chiral substrates in racemic or enantiomerically enriched form using one or both enantiomers of a catalyst. The key ...point of the reactions is the highly regioselective formation of products that are constitutional isomers. The selectivity is mediated by different interactions of the enantiomerically pure catalysts with both enantiomers of the substrate. Ideally, for racemic substrates, the reactions result in highly efficient parallel resolutions and for enantiomerically pure substrates, in highly regioselective reactions for each enantiomer of the catalyst. “Regiodivergent catalysis” is highly interesting for diversity‐oriented synthesis (DOS) because it provides branching points for the generation of functional and structural diversity.
A catalytic fork in the road: Regiodivergent catalysis describes a class of highly selective reactions of chiral substrates in racemic or enantiomerically enriched form with one or both enantiomers of the catalyst. Its key point is the highly regioselective, catalyst‐controlled formation of products that are constitutional isomers. Regiodivergent catalysis is attractive for parallel resolutions and for diversity‐oriented synthesis in pharmaceutical applications.
Recent researches of the novel 4
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Einstein–Gauss–Bonnet (EGB) gravity have attracted great attention. In this paper, we investigate the validity of the weak cosmic censorship conjecture for a novel ...4
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charged EGB black hole with test charged scalar field and test charged particle respectively. For the test charged field scattering process, we find that both extremal and near-extremal black holes cannot be overcharged. For the test charged particle injection, to first order, an extremal black hole cannot be overcharged while a near-extremal 4
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charged EGB black hole can be destroyed. To second order, however, both extremal and near-extremal 4
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charged EGB black holes can be overcharged for positive Gauss–Bonnet coupling constant; for negative Gauss–Bonnet coupling constant, an extremal black hole cannot be overcharged and the validity of the weak cosmic censorship conjecture for a near-extremal black hole depends on the Gauss–Bonnet coupling constant.
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