High‐Voltage Aqueous Mg‐Ion Batteries Enabled by Solvation Structure Reorganization

Herein, an eco-friendly and high safety aqueous Mg-ion electrolyte (AME) with a wide electrochemical stability window (ESW) $≈$ 3.7 V, containing polyethylene glycol (PEG) and low-concentration salt (0.8 m Mg(TFSI)$_2$), is proposed by solvation structure reorganization of AME. The PEG agent significantly alters the Mg$^{2+}$ solvation and hydrogen bonds network of AMEs and forms the direct coordination of Mg$^{2+}$ and TFSI-, thus enhancing the physicochemical and electrochemical properties of electrolytes. As an exemplary material, V$_2$O$_5$ nanowires are tested in this new AME and exhibit initial high discharge/charge capacity of 359/326 mAh g$^{-1}$ and high capacity retention of 80% after 100 cycles. The high crystalline $α$-V$_2$O$_5$ shows two 2-phase transition processes with the formation of $ε$-Mg$_{0.6}$V$_2$O$_5$ and Mg-rich Mg$_x$V$_2$O$_5$ (x $≈$1.0) during the first discharge. Mg-rich Mg$_x$V$_2$O$_5$ (x $≈$ 1.0) phase formed through electrochemical Mg-ion intercalation at room temperature is for the first time observed via XRD. Meanwhile, the cathode electrolyte interphase (CEI) in aqueous Mg-ion batteries is revealed for the first time. MgF$_2$ originating from the decomposition of TFSI- is identified as the dominant component. This work offers a new approach for designing high-safety, low-cost, eco-friendly, and large ESW electrolytes for practical and novel aqueous multivalent batteries

Introgression of Powdery Mildew Resistance Gene Pm56 on Rye Chromosome Arm 6RS Into Wheat

Powdery mildew, caused by the fungus Blumeria graminis f. sp. tritici, represents a yield constraint in many parts of the world. Here, the introduction of a resistance gene carried by the cereal rye cv. Qinling chromosome 6R was transferred into wheat in the form of spontaneous balanced translocation induced in plants doubly monosomic for chromosomes 6R and 6A. The translocation, along with other structural variants, was detected using in situ hybridization and genetic markers. The differential disease response of plants harboring various fragments of 6R indicated that a powdery mildew resistance gene(s) was present on both arms of rye chromosome 6R. Based on karyotyping, the short arm gene, designated Pm56, was mapped to the subtelomere region of the arm. The Robertsonian translocation 6AL⋅6RS can be exploited by wheat breeders as a novel resistance resource

Deep functional analysis of synII, a 770-kilobase synthetic yeast chromosome

INTRODUCTION Although much effort has been devoted to studying yeast in the past few decades, our understanding of this model organism is still limited. Rapidly developing DNA synthesis techniques have made a “build-to-understand” approach feasible to reengineer on the genome scale. Here, we report on the completion of a 770-kilobase synthetic yeast chromosome II (synII). SynII was characterized using extensive Trans-Omics tests. Despite considerable sequence alterations, synII is virtually indistinguishable from wild type. However, an up-regulation of translational machinery was observed and can be reversed by restoring the transfer RNA (tRNA) gene copy number. RATIONALE Following the “design-build-test-debug” working loop, synII was successfully designed and constructed in vivo. Extensive Trans-Omics tests were conducted, including phenomics, transcriptomics, proteomics, metabolomics, chromosome segregation, and replication analyses. By both complementation assays and SCRaMbLE (synthetic chromosome rearrangement and modification by loxP -mediated evolution), we targeted and debugged the origin of a growth defect at 37°C in glycerol medium. RESULTS To efficiently construct megabase-long chromosomes, we developed an I- Sce I–mediated strategy, which enables parallel integration of synthetic chromosome arms and reduced the overall integration time by 50% for synII. An I- Sce I site is introduced for generating a double-strand break to promote targeted homologous recombination during mitotic growth. Despite hundreds of modifications introduced, there are still regions sharing substantial sequence similarity that might lead to undesirable meiotic recombinations when intercrossing the two semisynthetic chromosome arm strains. Induction of the I- Sce I–mediated double-strand break is otherwise lethal and thus introduced a strong selective pressure for targeted homologous recombination. Since our strategy is designed to generate a markerless synII and leave the URA3 marker on the wild-type chromosome, we observed a tenfold increase in URA3 -deficient colonies upon I- Sce I induction, meaning that our strategy can greatly bias the crossover events toward the designated regions. By incorporating comprehensive phenotyping approaches at multiple levels, we demonstrated that synII was capable of powering the growth of yeast indistinguishably from wild-type cells (see the figure), showing highly consistent biological processes comparable to the native strain. Meanwhile, we also noticed modest but potentially significant up-regulation of the translational machinery. The main alteration underlying this change in expression is the deletion of 13 tRNA genes. A growth defect was observed in one very specific condition—high temperature (37°C) in medium with glycerol as a carbon source—where colony size was reduced significantly. We targeted and debugged this defect by two distinct approaches. The first approach involved phenotype screening of all intermediate strains followed by a complementation assay with wild-type sequences in the synthetic strain. By doing so, we identified a modification resulting from PCRTag recoding in TSC10 , which is involved in regulation of the yeast high-osmolarity glycerol (HOG) response pathway. After replacement with wild-type TSC10 , the defect was greatly mitigated. The other approach, debugging by SCRaMbLE, showed rearrangements in regions containing HOG regulation genes. Both approaches indicated that the defect is related to HOG response dysregulation. Thus, the phenotypic defect can be pinpointed and debugged through multiple alternative routes in the complex cellular interactome network. CONCLUSION We have demonstrated that synII segregates, replicates, and functions in a highly similar fashion compared with its wild-type counterpart. Furthermore, we believe that the iterative “design-build-test-debug” cycle methodology, established here, will facilitate progression of the Sc2.0 project in the face of the increasing synthetic genome complexity. SynII characterization. ( A ) Cell cycle comparison between synII and BY4741 revealed by the percentage of cells with separated CEN2-GFP dots, metaphase spindles, and anaphase spindles. ( B ) Replication profiling of synII (red) and BY4741 (black) expressed as relative copy number by deep sequencing. ( C ) RNA sequencing analysis revealed that the significant up-regulation of translational machinery in synII is induced by the deletion of tRNA genes in synII. </jats:sec

Cotyledon-greening analysis on <i>35S</i>:<i>TsRAVs</i> transgenic <i>Arabidopsis</i> seedlings.

<p>(A) Phenotypic comparison of wild-type and <i>35S</i>:<i>TsRAVs</i> transgenic <i>Arabidopsis</i> seedlings after grown on normal 1/2 MS medium (upper panel) or on 1/2 MS medium with 0.5 <i>μ</i>M ABA for 6 days (lower panel). (B) Cotyledon-greening percentages of <i>35S</i>:<i>TsRAVs</i> transgenic <i>Arabidopsis</i> seedlings after grown on 1/2 MS medium with 0.5 <i>μ</i>M ABA for 6 days. Each data bar represents the mean ± SE of three replicates. More than 100 seeds were measured in each replicate. Different letters indicate significant differences among means (<i>P</i><0.05 by Tukey’s test).</p

ABA sensitivity of <i>35S</i>:<i>TsRAVs</i> transgenic <i>Arabidopsis</i> plants.

<p>(A) Germination rates of <i>35S</i>:<i>TsRAVs</i> transgenic <i>Arabidopsis</i> seeds on 1/2 MS media with 1 <i>μ</i>M ABA. Each data bar represents the means ± SE of three replicates. More than 100 seeds were measured in each replicate. (B) Inhibitory effect of 1 <i>μ</i>M ABA on <i>35S</i>:<i>TsRAVs</i> transgenic <i>Arabidopsis</i> seed germination rates. Each data bar represents the mean ± SE of three replicates. More than 50 seedlings were measured in each replicate. Different letters indicate significant differences among means (<i>P</i><0.05 by Tukey’s test). (C) Inhibitory effect of 30 <i>μ</i>M ABA on <i>35S</i>:<i>TsRAVs</i> transgenic <i>Arabidopsis</i> seedling root elongation. Seedlings were grown on normal media for 5 days before being transferred onto 1/2 MS medium with 30 <i>μ</i>M ABA and grown for other 6 days. Each data bar represents the mean ± SE of three replicates. More than 50 seedlings were measured in each replicate. Different letters indicate significant differences among means (<i>P</i><0.05 by Tukey’s test).</p

Sequence characterization of RAV family members of <i>Thellungiella salsuginea</i> and <i>Arabidopsis thaliana</i>.

<p>(A) Phylogenetic tree of the RAV family members in <i>Thellungiella salsuginea</i> and <i>Arabidopsis thaliana</i>. The phylogenetic tree was constructed using full-length protein sequences by the maximum-likelihood method with MEGA 5.0 and a bootstrap value of 1,000. The two major phylogenetic clades are designated as groups A and B. Shown on the right are diagrams of RAV proteins with information on the structure and position of different protein domains. (B) RAV subfamily-specific amino acids and their locations along the RAV full-length sequences. The amino acid sequences in boxes represent the conserved AP2 and B3 DNA-binding domains, which are characteristic of RAV transcription factors. The locations of the conserved YRG and RAYD elements are indicated as well. (C) Schematic illustrations of the types and distributions of motifs for each TsRAV family members with a same group. Motifs were identified using the MEME search tool and numerically marked according to their statistical significance (low <i>E</i>-value) in a descending order.</p

Phenotypic characterization of <i>35S</i>:<i>TsRAVs</i> transgenic <i>Arabidopsis</i> plants under normal conditions.

<p>(A) Primary root length of 7-d-old <i>35S</i>:<i>TsRAVs</i> transgenic <i>Arabidopsis</i> seedlings grown on 1/2 MS media. Each data bar represents the means ± SE of three replicates. More than 50 seedlings were measured for each replicates. Different letters indicate significant differences among means (<i>P</i><0.05 by Tukey’s test). (B) Germination rates of <i>35S</i>:<i>TsRAVs</i> transgenic <i>Arabidopsis</i> seeds during a 5-day period on normal 1/2 MS media. Each data bar represents the means ± SE of three replicates. More than 100 seeds were measured in each replicated.</p