A lncRNA fine-tunes salicylic acid biosynthesis to balance plant immunity and growth.

Constitutive activation of plant immunity is detrimental to plant growth and development. Here, we uncover the role of a long non-coding RNA (lncRNA) in fine-tuning the balance of plant immunity and growth. We find that a lncRNA termed salicylic acid biogenesis controller 1 (SABC1) suppresses immunity and promotes growth in healthy plants. SABC1 recruits the polycomb repressive complex 2 to its neighboring gene NAC3, which encodes a NAC transcription factor, to decrease NAC3 transcription via H3K27me3. NAC3 activates the transcription of isochorismate synthase 1 (ICS1), a key enzyme catalyzing salicylic acid (SA) biosynthesis. SABC1 thus represses SA production and plant immunity via decreasing NAC3 and ICS1 transcriptions. Upon pathogen infection, SABC1 is downregulated to derepress plant resistance to bacteria and viruses. Together, our findings reveal lncRNA SABC1 as a molecular switch in balancing plant defense and growth by modulating SA biosynthesis.

Epitaxial Grown Carbon Nanotubes Reinforced Pyrocarbon Matrix in C/C Composites with Improved Mechanical Properties.

In order to achieve the highly efficient preparation of high-performance carbon/carbon (C/C) composites, epitaxial grown carbon nanotubes (CNTs) and a pyrocarbon matrix were simultaneously synthesized to fabricate CNT-reinforced C/C composites (CC/C composites). With precise control of the temperature gradient, CNTs and the pyrocarbon matrix could grow synchronously within a 2D needle-punched carbon fiber preform. Surprisingly, the CNTs remained intact within the pyrocarbon matrix at the nano-level, and the CNT-reinforced nano-pyrocarbon matrix was compact, with virtually no gaps and pores, which were tightly connected with the carbon fibers without cracks. Based on the results of Raman analysis, there is less residual stress in the CNT-reinforced pyrocarbon matrix and carbon fibers, and less of a mismatch between the coefficient and thermal expansion. Additionally, CC/C composites fabricated by this method could achieve a low density, open porosity with a large size, and improved mechanical properties. More importantly, our work provides a rational design strategy for the highly efficient preparation and structural design of high-performance CNT-einforced C/C composites.

DEAD-box helicases modulate dicing body formation in Arabidopsis.

Eukaryotic cells contain numerous membraneless organelles that are made from liquid droplets of proteins and nucleic acids and that provide spatiotemporal control of various cellular processes. However, the molecular mechanisms underlying the formation and rapid stress-induced alterations of these organelles are relatively uncharacterized. Here, we investigated the roles of DEAD-box helicases in the formation and alteration of membraneless nuclear dicing bodies (D-bodies) in Arabidopsis thaliana We uncovered that RNA helicase 6 (RH6), RH8, and RH12 are previously unidentified D-body components. These helicases interact with and promote the phase separation of SERRATE, a key component of D-bodies, and drive the formation of D-bodies through liquid-liquid phase separations (LLPSs). The accumulation of these helicases in the nuclei decreases upon Turnip mosaic virus infections, which couples with the decrease of D-bodies. Our results thus reveal the key roles of RH6, RH8, and RH12 in modulating D-body formation via LLPSs.

[Distinguishing the Compositions and Sources of the Chromophoric Dissolved Organic Matter in a Typical Karst River During the Dry Season: A Case Study in Bitan River, Jinfo Mountain].

Since resistant dissolved organic matter (RDOM) plays a critically important role in a karst carbon sink, one of the most important continental carbon sinks, research focusing on the origination, transportation, and translation of RDOM in a karst water system is important. Currently, 3D-fluorescence EEMs are used to detect the composition and origination of chromophoric dissolved organic matter (CDOM), an important part of RDOM. This is a very fast and efficient method for CDOM analysis. In this study, 3D-fluorencence EEMs combined with UV-visible absorption spectrum were used to analyze the composition and origination of CDOM in the Bitan River at Jinfo Mountain. Samples were collected from nine sampling sites from January to March 2017 and analyzed with CDOM EEMs and UV-visible absorption spectrums. In addition hydrochemical characteristics were determined and then samples were stimulated with PARAFAC to detect the chromophoric fluorescent groups and indexes. The PARAFAC stimulation revealed three chromophoric fluorescent groups in which fulvic acid was the largest component, accounting for about 44%, with a humic acid content of about 32% and tyrosine-like acid content of about 24%. Four indexes: FI, BIX, HIX, and ß∶α, were calculated, and the mean values were 2.06, 0.87, 4.35 and 0.69, which showed relatively high FI, BIX, and ß∶α values and a low HIX value, implying that the CDOM was autochthonous and originated from microbes and aquatic plants in the dry season. The spatial dynamic of the index revealed an increased BIX and decreased HIX from the upstream area to the downstream area, implying the impact of land-use and human activities. The forest soil input more humic acid and agriculture input more N and P resulting in flourishing aquatic plants and microbes. Moreover, the correlation coefficients of DIC and humic acid, tyrosine-like acid were 0.515 (P<0.05) and 0.644 (P<0.01), from which it could be inferred that DIC contributed to CDOM formation. The conclusions of this study revealed that DIC would be fixed by karst water aquatic plants and microbes and then sink as autochthonous CDOM and become part of karst water carbon sink.

Facile synthesis of NiCo2O4@Polyaniline core-shell nanocomposite for sensitive determination of glucose.

In this work, the core-shell structure of NiCo2O4@Polyaniline (NiCo2O4@PANI) nanocomposite is fabricated via a facile hydrothermal treatment followed by a post-Polyaniline (PANI) coating process. The synthesized materials are characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectrometer. The biosensing properties of NiCo2O4@PANI composite and NiCo2O4 nanoparticles toward glucose are studied based on glassy carbon electrode. Electrochemical studies indicate that the obtained core-shell NiCo2O4@PANI composite shows higher electrocatalytic activity toward the oxidation of glucose, compared with NiCo2O4 nanoparticles. The enhanced performance is related to the core-shell structure of NiCo2O4@PANI composite and the outstanding conductivity of the polyaniline shell. At a potential of +0.5V, the NiCo2O4@PANI nanocomposite modified glass carbon electrode demonstrates a wide linear range up to 4.7350mM with sensitivity of 4.55mAmM(-1)cm(-2) and detection limit of 0.3833µM. It also shows significant electrochemical stability, good reproducibility and excellent selectivity. The results suggest that the NiCo2O4@PANI nanocomposite is a promising electrode material for electrochemical biosensor.

NiO/graphene nanocomposite for determination of H2O2 with a low detection limit.

In this study, we have reported the preparation of NiO/graphene (NiO/GR) nanocomposite for determination of H2O2 via a convenient solid reaction. The electrocatalytic behaviors towards H2O2 are investigated by cyclic voltammetry and chronoamperometry in alkaline aqueous solution. Electrochemical results indicate that the NiO/GR nanocomposite exhibits a high peak current towards the oxidation of H2O2. Moreover, high electrocatalytic activity toward the oxidation of H2O2 is observed with a low detection limit of 0.7664 µM, high sensitivity of 591 µA mM(-1) cm(-2), a wide linear range of 0.25-4.75 mM (R(2)=0.9971). Besides, the sensor presents many attractive features such as high stability and reproducibility.