The OSU1/QUA2/TSD2-Encoded Putative Methyltransferase Is a Critical Modulator of Carbon and Nitrogen Nutrient Balance Response in Arabidopsis

The balance between carbon (C) and nitrogen (N) nutrients must be tightly coordinated so that cells can optimize their opportunity for metabolism, growth and development. However, the C and N nutrient balance perception and signaling mechanism remains poorly understood. Here, we report the isolation and characterization of two allelic oversensitive to sugar1 mutants (osu1-1, osu1-2) in Arabidopsis thaliana. Using the cotyledon anthocyanin accumulation and root growth inhibition assays, we show that the osu1 mutants are more sensitive than wild-type to both of the imbalanced C/N conditions, high C/low N and low C/high N. However, under the balanced C/N conditions (low C/low N or high C/high N), the osu1 mutants have similar anthocyanin levels and root lengths as wild-type. Consistently, the genes encoding two MYB transcription factors (MYB75 and MYB90) and an Asn synthetase isoform (ASN1) are strongly up-regulated by the OSU1 mutation in response to high C/low N and low C/high N, respectively. Furthermore, the enhanced sensitivity of osu1-1 to high C/low N with respect to anthocyanin accumulation but not root growth inhibition can be suppressed by co-suppression of MYB75, indicating that MYB75 acts downstream of OSU1 in the high C/low N imbalance response. Map-based cloning reveals that OSU1 encodes a member of a large family of putative methyltransferases and is allelic to the recently reported QUA2/TSD2 locus identified in genetic screens for cell-adhesion-defective mutants. Accumulation of OSU1/QUA2/TSD2 transcript was not regulated by C and N balance, but the OSU1 promoter was slightly more active in the vascular system. Taken together, our results show that the OSU1/QUA2/TSD2-encoded putative methyltransferase is required for normal C/N nutrient balance response in plants

Highly efficient CO2 capture by mixed matrix membranes containing three-dimensional covalent organic framework fillers

10.1039/c8ta10333jJOURNAL OF MATERIALS CHEMISTRY A794549-456

NiCoP/CoP Nanoparticles Supported on Ti4O7 as the Electrocatalyst Possessing an Excellent Catalytic Performance toward the Hydrogen Evolution Reaction

NiCoP/CoP nanoparticles and NiCoP/CoP nanoparticles supported on carbon black (NiCoP/CoP-C) and titanium suboxide (NiCoP/CoP-Ti4O7), respectively, are prepared by a hydrothermal method followed by two steps of low temperature annealing processes. As hydrogen evolution reaction (HER) catalysts, the activities of the three catalysts are measured by linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and so on. Impressively, NiCoP/CoP Ti4O7 shows the best electrocatalytic performance for HER with an ultralow overpotential of 128 mV at 10 mA cm(-2) along with negligible catalytic activity degradation after 1000 cycles of CV, which is partly ascribed to the high conductivity and corrosion resistance of Ti4O7. According to the characterization of X-ray photoelectron spectra (XPS), it is found that NiCoP/CoP Ti4O7 has a higher ratio of Ni2+ and surface defects, which can be also used to explain the reason why NiCoP/CoP Ti4O7 owns the most preeminent HER activity among the three catalysts.</p