Rice (Oryza sativa) is sensitive to low temperatures, which affects the yield and quality of rice. Therefore, uncovering the molecular mechanisms behind chilling tolerance is a critical task for improving cold tolerance in rice cultivars. Here, we report that OsWRKY63, a WRKY transcription factor with an unknown function, negatively regulates chilling tolerance in rice. OsWRKY63-overexpressing rice lines are more sensitive to cold stress. Conversely, OsWRKY63-knockout mutants generated using a CRISPR/Cas9 genome editing approach exhibited increased chilling tolerance. OsWRKY63 was expressed in all rice tissues, and OsWRKY63 expression was induced under cold stress, dehydration stress, high salinity stress, and ABA treatment. OsWRKY63 localized in the nucleus plays a role as a transcription repressor and downregulates many cold stress-related genes and reactive oxygen species scavenging-related genes. Molecular, biochemical, and genetic assays showed that OsWRKY76 is a direct target gene of OsWRKY63 and that its expression is suppressed by OsWRKY63. OsWRKY76-knockout lines had dramatically decreased cold tolerance, and the cold-induced expression of five OsDREB1 genes was repressed. OsWRKY76 interacted with OsbHLH148, transactivating the expression of OsDREB1B to enhance chilling tolerance in rice. Thus, our study suggests that OsWRKY63 negatively regulates chilling tolerance through the OsWRKY63-OsWRKY76-OsDREB1B transcriptional regulatory cascade in rice.
Ni-rich cathode (Ni > 0.8) provides
a low-cost and high-energy-density
solution to the next-generation lithium-ion batteries. Unfortunately,
severe capacity fading of Ni-rich cathode caused by the interfacial
and bulk structural degradation impeded its application. Herein, Zr
doping and Li6Zr2O7 coating are applied
to a Ni-rich LiNi0.83Co0.12Mn0.05O2 (NCM) layered cathode material, and the modified material
exhibits excellent cycle stability. The 1%Zr-NCM cathode material
maintains a discharge capacity of 173.9 mAh g–1 at
1 C after 200 cycles in the 2.5–4.3 V voltage range at 25 °C,
corresponding to a capacity retention of 94.6%; however, the unmodified
NCM only delivers 129.9 mAh g–1 (capacity retention
68.6%). The synergistic effect of bulk Zr doping and surface Li6Zr2O7 coating improves the cycle stability
of the Ni-rich material. Zr doped into the bulk could form a strong
Zr–O bond to stabilize the layered structure, and Zr located
in the Li layer can act as a pillar to maintain the layered structure
and reduce Li+/Ni2+ mixing. In addition, the
Li6Zr2O7 coating layer can also play
a dual role in promoting Li+ migration and suppressing
surface side reactions. This work demonstrates that sufficiently utilizing
zirconium to enhance the electrochemical performance of cathode materials
is a feasible and promising strategy.
Ni‐rich cathode is considered a promising cathode for its high specific capacity. However, a sharp capacity attenuation induced by interface problems limits the application of the cathode material. Herein, we propose a practical surface modification strategy by introducing diboron trioxide (B2O3) to the surface of LiNi0.83Co0.12Mn0.05O2 (NCM) cathode materials. B2O3‐modified NCM shows superior cyclic stability with a capacity retention of 87.7 % at 1 C after 200 cycles in comparison to 69.4 % for a bare NCM. On the basis of material and electrochemical characterizations, we conclude that the superior cycle stability of B2O3‐modified NCM material benefits from the formation of B2O3 coating and B3+ doping on the surface. The B2O3 coating layer that is confirmed by scanning and transmission electron microscopy can suppress surface side reactions and reduce the content of Li2CO3 on the surface. The B3+‐doping surface is verified by X‐ray diffraction and X‐ray photoelectron spectroscopy and triggers a reduction of a small amount of Ni3+ to Ni2+. Furthermore, the combination of surface B2O3 coating and B3+ doping inhibits the irreversible phase transitions and extension of microcracks in the NCM material. The above surface modification strategy provides a direction for the acquisition of long‐life cathode materials.
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