Sodium Storage Performance and Mechanism of MnO2 with Different Phase Structures (α, ß, γ, δ) as Anode Materials for Sodium-Ion Batteries.

An in-depth understanding of the links between the phase structure and electrochemical property is crucial for the advancement of high-performance anode materials. Herein, the sodium storage performance and mechanisms of MnO2 with four distinct phase structures (α, ß, γ, and δ) as anodes are systematically investigated. Among the four materials, the layered δ-MnO2 nanoflowers exhibit the best sodium storage performances, characterized by a specific capacity of 303.6 mA h g-1 after 100 cycles at 200 mA g-1, cyclability of 247.3 mA h g-1 after 500 cycles at 1000 mA g-1, and high-rate performance of 184.5 mA h g-1 at 3000 mA g-1. Furthermore, δ-MnO2 shows the most pronounced pseudocapacitance behavior during discharge/charge processes among the four materials. Ex situ XRD and TEM analyses reveal that the sodium storage reactions of α-, ß-, and γ-MnO2 proceed via a conversion reaction mechanism, while the sodium storage reaction of δ-MnO2 is controlled by an insertion/deinsertion mechanism. The findings presented in this study may offer insights into the structure regulation and performance promotion of MnO2-based anode materials for SIBs.

SUMOylation facilitates the assembly of a Nuclear Factor-Y complex to enhance thermotolerance in Arabidopsis.

Heat stress (HS) has serious negative effects on plant development and has become a major threat to agriculture. A rapid transcriptional regulatory cascade has evolved in plants in response to HS. Nuclear Factor-Y (NF-Y) complexes are critical for this mechanism, but how NF-Y complexes are regulated remains unclear. In this study, we identified NF-YC10 (NF-Y subunit C10), a central regulator of the HS response in Arabidopsis thaliana, as a substrate of SUMOylation, an important post-translational modification. Biochemical analysis showed that the SUMO ligase SIZ1 (SAP AND MIZ1 DOMAIN-CONTAINING LIGASE1) interacts with NF-YC10 and enhances its SUMOylation during HS. The SUMOylation of NF-YC10 facilitates its interaction with and the nuclear translocation of NF-YB3, in which the SUMO interaction motif (SIM) is essential for its efficient association with NF-YC10. Further functional analysis indicated that the SUMOylation of NF-YC10 and the SIM of NF-YB3 are critical for HS-responsive gene expression and plant thermotolerance. These findings uncover a role for the SIZ1-mediated SUMOylation of NF-YC10 in NF-Y complex assembly under HS, providing new insights into the role of a post-translational modification in regulating transcription during abiotic stress responses in plants.