DNA methylation is an epigenetic mark that silences transposable elements (TEs) and repeats. Whereas the establishment and maintenance of DNA methylation are relatively well understood, little is known about their dynamics and biological relevance in plant and animal innate immunity. Here, we show that some TEs are demethylated and transcriptionally reactivated during antibacterial defense in Arabidopsis. This effect is correlated with the down-regulation of key transcriptional gene silencing factors and is partly dependent on an active demethylation process. DNA demethylation restricts multiplication and vascular propagation of the bacterial pathogen Pseudomonas syringae in leaves and, accordingly, some immune-response genes, containing repeats in their promoter regions, are negatively regulated by DNA methylation. This study provides evidence that DNA demethylation is part of a plant-induced immune response, potentially acting to prime transcriptional activation of some defense genes linked to TEs/repeats. epigenetics | RNA silencing | MAMP

The residual defects and groups in chemically reduced graphene oxide cannot only improve the impedance match characteristic and prompt energy transition from contiguous states to Fermi level, but also introduce defect polarization relaxation and groups’ electronic dipole relaxation, which are all in favor of electromagnetic wave penetration and absorption. The chemically reduced graphene oxide shows enhanced microwave absorption compared with graphite and carbon nanotubes, and can be expected to display better absorption than high quality graphene, exhibiting a promising prospect as microwave absorbing material.

Significant efforts have been devoted to develop efficient visible-light-driven photocatalysts for the conversion of CO2 to chemical fuels. The photocatalytic efficiency for this transformation largely depends on CO2 adsorption and diffusion. However, the CO2 adsorption on the surface of photocatalysts is generally low due to their low specific surface area and the lack of matched pores. Here we report a well-defined porous hypercrosslinked polymer-TiO2-graphene composite structure with relatively high surface area i.e., 988 m2 g−1 and CO2 uptake capacity i.e., 12.87 wt%. This composite shows high photocatalytic performance especially for CH4 production, i.e., 27.62 μmol g−1 h−1, under mild reaction conditions without the use of sacrificial reagents or precious metal co-catalysts. The enhanced CO2 reactivity can be ascribed to their improved CO2 adsorption and diffusion, visible-light absorption, and photo-generated charge separation efficiency. This strategy provides new insights into the combination of microporous organic polymers with photocatalysts for solar-to-fuel conversion.

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Anatase TiO2 nanosheets supported on reduced graphene oxide (RGO) were synthesized via a one-step, solvothermal method. During the solvothermal step, graphene oxide (GO) was reduced to RGO, and, subsequently, anatase TiO2 with 73.7% exposed {001} facets was grown in situ on the surfaces of the RGO nanosheets. Compared with pure TiO2, the RGO/TiO2 hybrid nanocomposite had improved photoactivity as a result of effective photoinduced electron transfer from TiO2 to the RGO acceptor through interfacial interactions. Trapping tests showed that the oxidation of dye molecules proceeded for about 22% through the reaction with (•)OH radicals, and the remaining 78% occurred via direct interactions with holes. The holes left in TiO2 crystals were the main reason for the enhanced photocatalytic properties of the RGO/TiO2 composite. This paper not only reports the fabrication of highly active photocatalysts but also gives deeper insight into the photocatalytic mechanism of carbon/TiO2 composites.

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Developing highly efficient hydrogen evolution reaction (HER) catalysts in alkaline media is considered significant and valuable for water splitting. Herein, it is demonstrated that surface reorganization engineering by oxygen plasma engraving on electocatalysts successfully realizes a dramatically enhanced alkaline HER activity. Taking CoP nanowire arrays grown on carbon cloth (denoted as CoP NWs/CC) as an example, the oxygen plasma engraving can trigger moderate CoOx species formation on the surface of the CoP NWs/CC, which is visually verified by the X‐ray absorption fine structure, high‐resolution transmission electron microscopy, and energy‐dispersive spectrometer (EDS) mapping. Benefiting from the moderate CoOx species formed on the surface, which can promote the water dissociation in alkaline HER, the surface reorganization of the CoP NWs/CC realizes almost fourfold enhanced alkaline HER activity and a 180 mV decreased overpotential at 100 mA cm−2, compared with the pristine ones. More interestingly, this surface reorganization strategy by oxygen plasma engraving can also be effective to other electrocatalysts such as free‐standing CoP, Co4N, O‐CoSe2, and C‐CoSe2 nanowires, which verifies the universality of the strategy. This work thus opens up new avenues for designing alkaline HER electrocatalysts based on oxygen plasma engraving.

Nickel nanomaterials with a wide range of morphologies and sizes, such as superfine nanoparticles, urchinlike chains, smooth chains, rings, and hexagonal Ni/Ni(OH)2 heterogeneous structure plates, are synthesized in a single reaction system by simply adjusting the reaction conditions. The morphology transformation mechanism is systematically investigated. Magnetic measurement of urchinlike chains, smooth chains, and rings shows that the saturation magnetization (M s) decreases with reduced sample size, and remanent magnetization (M r) decreases with increasing reaction temperature. Additionally, coercivity (H c) of urchinlike chains which is apparently larger than that of bulk nickel depends more on size than on shape anisotropy according to spherical chain reversal magnetization model. Enhanced microwave absorption of Ni/Ni(OH)2 hexagonal plates compared with smooth chains and rings is due to the synergistic effect of magnetic loss and dielectric loss. Particularly, the urchinlike nickel chains exhibit a best absorption property in contrast with other as-synthesized samples and other reported nickel structures, which can be attributed to the geometrical effect, high initial permeability, point discharge effect, and multiple absorption. The prepared nickel nanomaterials can be applied as promising absorbing materials.