Aluminum (Al) toxicity in plants is one of the primary constraints in crop production. Al-3, the most toxic form of Al, is released into soil under acidic conditions and causes extensive damage to plants, especially in the roots. In rice, Al tolerance requires the ASR5 gene, but the molecular function of ASR5 has remained unknown. Here, we perform genome-wide analyses to identify ASR5-dependent Al-responsive genes in rice. Based on ASR5_RNAi silencing in plants, a global transcriptome analysis identified a total of 961 genes that were responsive to Al treatment in wild-type rice roots. Of these genes, 909 did not respond to Al in the ASR5_RNAi plants, indicating a central role for ASR5 in Al-responsive gene expression. Under normal conditions, without Al treatment, the ASR5_RNAi plants expressed 1.756 genes differentially compared to the wild-type plants, and 446 of these genes responded to Al treatment in the wild-type plants. Chromatin immunoprecipitation followed by deep sequencing identified 104 putative target genes that were directly regulated by ASR5 binding to their promoters, including the STAR1 gene, which encodes an ABC transporter required for Al tolerance. Motif analysis of the binding peak sequences revealed the binding motif for ASR5, which was confirmed via in vitro DNA-binding assays using the STAR1 promoter. These results demonstrate that ASR5 acts as a key transcription factor that is essential for Al-responsive gene expression and Al tolerance in rice.

Guided by a simple strategy in search of new superconducting materials, we predict that high-temperature superconductivity can be realized in classes of high-density materials having strong sp(3) chemical bonding and high lattice symmetry. We examine in detail sodalite carbon frameworks doped with simple metals such as Li, Na, and Al. Though such materials share some common features with doped diamond, their doping level is not limited, and the density of states at the Fermi level in them can be as high as that in the renowned MgB2. Together with other factors, this boosts the superconducting temperature (T-c) in the materials investigated to higher levels compared to doped diamond. For example, the T-c of sodalitelike NaC6 is predicted to be above 100 K. This phase and a series of other sodalite-based superconductors are predicted to be metastable phases but are dynamically stable. Owing to the rigid carbon framework of these and related dense carbon materials, these doped sodalite-based structures could be recoverable as potentially useful superconductors.

Static pressure is an alternative method to chemical pressure for tuning the crystal structure, bonds, and physical properties of materials, and is a significant technique for the synthesis of novel materials and fundamental research. In this letter, we report the crystallization and phase transformation of p-xylene under high pressure. Our optical micrographic observations and the appearance of lattice modes in the Raman and infrared (IR) spectra indicated that p-xylene crystallizes at similar to 0.1 GPa. The X-ray diffraction (XRD) pattern at 0.84 GPa suggests that the crystallized p-xylene had a monoclinic phase with the Cc(9) space group. The sharp shrinkage of the lattice at similar to 13 GPa and the solid state of the decompressed sample we observed suggests a new crystalline phase of p-xylene. The in situ XRD showed that the new crystalline phase was still a monoclinic structure but with a different space group of C2(5), indicating that a phase transition occurred during further compression. The mass spectrometry experiment confirmed phase transition polymerization, with mainly trimer and tetramer polymers. Our findings suggest an easy and efficient method for crystallizing and polymerizing p-xylene under high pressure.

Zebrafish Liver-enriched gene 1a (Leg1a) and Leg1b are liver-produced serum proteins encoded by two adjacently linked homologous genes leg1a and leg1b, respectively. We previously showed that maternal-zygotic (MZ) leg1a null mutant developed a small liver at 3.5 days post-fertilization (dpf) during winter-time or under UV-treatment and displayed an abnormal stature at its adulthood. It is puzzling why Leg1b, which shares 89.3% identity with Leg1a and co-expressed with Leg1a, cannot fully compensate for the loss-of-function of Leg1a in the leg1a(zju1) MZ mutant. Here we report that Leg1a and Leg1b share eight cysteine residues but differ in amino acid residue 358, which is a serine in Leg1a but cysteine (C-358) in Leg1b. We find that Leg1b forms an intermolecular disulfide bond through C-358. Mutating C-358 to Methionine (M-358) does not affect Leg1b secretion whereas mutating other conserved cysteine residues do. We propose that the intermolecular disulfide bond in Leg1b might establish a rigid structure that makes it functionally different from Leg1a under certain oxidative conditions. (c) 2021 Published by Elsevier Inc.