Temporal transcriptomics reveal crucial networks underlying jasmonate-mediated diurnal floret opening and closure in rice.

Diurnal floret opening and closure (DFOC) is essential for rice reproductive development and hybrid breeding, yet transcriptional dynamics and underlying regulatory networks remain poorly characterized. Here, we conducted high-temporal-resolution transcriptomic analyses of lodicules to dissect DFOC regulatory networks in two japonica rice cultivars. Analysis of differentially expressed genes (DEGs) uncovered core genes shared by both cultivars, primarily associated with jasmonic acid (JA) signaling and cell wall remodeling. By integrating DNA affinity purification sequencing (DAP-seq), we constructed core regulatory networks mediated by the basic helix-loop-helix transcription factor (TF) OsMYC2, governing DFOC in rice. We identified xyloglucan endotransglycosylase-related gene 1 (OsXTR1), which encodes a cell-wall loosening enzyme, as a key gene activated by OsMYC2 during DFOC. Disruption of OsXTR1 resulted in florets failing to close after opening, demonstrating its essential role in linking cell wall dynamics to hormonal regulation. Similarly, we identified a JA biosynthesis gene, allene oxide cyclase (OsAOC), which is implicated in DFOC through an OsMYC2-mediated positive-feedback loop. Additionally, we developed the RiceDFOC database ( http://zhoulab.zju.edu.cn/FT/index.html ), providing interactive access to spatiotemporal transcriptomes, co-expression networks, and phenomics data. Collectively, our study unveils a hierarchical OsMYC2-centric network that coordinates JA signaling and structural remodeling during DFOC, providing mechanistic insights and resources for optimizing rice breeding.