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Summary: Light and brassinosteroids (BR) are indispensable for plant growth and control cell division in the apical meristem. However, how external light signals cooperate with internal brassinosteroids to program root meristem development remains elusive.We reveal that the photoreceptor phytochrome B (phyB) guides the scaffold protein RACK1 to coordinate BR signaling for maintaining root meristematic activity. phyB and RACK1 promote early root meristem development.Mechanistically, RACK1 could reinforce the phyB–SPA1 association by interacting with both phyB and SPA1, which indirectly affects COP1‐dependent RACK1 degradation, resulting in the accumulation of RACK1 in roots. Subsequently, RACK1 interacts with BES1 to repress its DNA‐binding activity toward the target gene CYCD3;1, leading to the release of BES1‐mediated inhibition of CYCD3;1 transcription, and hence the promotion of root meristem development.Our study provides mechanistic insights into the regulation of root meristem development by combination of light and phytohormones signals through the photoreceptors and scaffold proteins. [ABSTRACT FROM AUTHOR]

Energy management strategy (EMS), as a core technology in fuel cell vehicles (FCVs), profoundly influences the lifespan of fuel cells and the economy of the vehicle. Aiming at the problem of the EMS of FCVs based on a global optimization algorithm not being applicable in real-time, a rule extraction-based EMS is proposed for fuel cell commercial vehicles. Based on the results of the dynamic programming (DP) algorithm in the CLTC-C cycle, the deep learning approach is employed to extract output power rules for fuel cell, leading to the establishment of a rule library. Using this library, a real-time applicable rule-based EMS is designed. The simulated driving platform is built in a CARLA, SUMO, and MATLAB/Simulink joint simulation environment. Simulation results indicate that the proposed strategy yields savings ranging from 3.64% to 8.96% in total costs when compared to the state machine-based strategy. [ABSTRACT FROM AUTHOR]

ABSCISIC ACID INSENSITIVE5 (ABI5), a key regulator of the abscisic acid (ABA) signalling pathway, plays a fundamental role in seed germination and post-germinative development. However, the molecular mechanism underlying the repression function of ABI5 remains to be elucidated. In this study, we demonstrate that the conserved eukaryotic WD40 repeat protein Receptor for Activated C Kinase 1 (RACK1) is a novel negative regulator of ABI5 in Arabidopsis. The RACK1 loss-of-function mutant is hypersensitive to ABA, while this phenotype is rescued by a mutation in ABI5. Moreover, overexpression of RACK1 suppresses ABI5 transcriptional activation activity for ABI5-targeted genes. RACK1 may also physically interact with ABI5 and facilitate its degradation. Furthermore, we found that RACK1 and the two substrate receptors CUL4-based E3 ligases (DWA1 and DWA2) function together to mediate the turnover of ABI5, thereby efficiently reducing ABA signalling in seed germination and post-germinative growth. In addition, molecular analyses demonstrated that ABI5 may bind to the promoter of RACK1 to repress its expression. Collectively, our findings suggest that RACK1 and ABI5 might form a feedback loop to regulate the homeostasis of ABA signalling in acute seed germination and early plant development. [ABSTRACT FROM AUTHOR]

Summary: Brassinosteroids (BRs) are a group of plant‐specific steroid hormones, which induces the rapid nuclear localization of the positive transcriptional factors BRASSINAZOLE RESISTANT1/2 (BZR1/2). However, the mechanisms underlying the regulation of nucleocytoplasmic shuttling of BZR1 remain to be fully elucidated.In this study, we show that the scaffold protein Receptor for Activated C Kinase 1 (RACK1) from Arabidopsis is involved in BR signaling cascades through mediating the nuclear localization of BZR1, which is tightly retained in the cytosol by the conserved scaffold protein 14‐3‐3s.RACK1 can interact with BZR1 and competitively decrease the 14‐3‐3 interaction with BZR1 in cytosol, which efficiently enhances the nuclear localization of BZR1. 14‐3‐3 also retains RACK1 in cytosol through their interaction. Conversely, BR treatment enhances the nuclear localization of BZR1 by disrupting the 14‐3‐3 interaction with RACK1 and BZR1.Our study uncovers a new mechanism that integrates two kinds of conserved scaffold proteins (RACK1 and 14‐3‐3) coordinating BR signaling event. [ABSTRACT FROM AUTHOR]