Zhang Rui, Xi Xiaohui, Hu Xiaozhou, Xiang Dan, Wang Yi, Pan Yu, He Xi, Zhang Yuhan, Hong Lilan, Yang Yuanzhu, Zhou Ming
State Key Laboratory of Plant Environmental Resilience, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
Institute of Nuclear Agricultural Sciences, Key Laboratory of Nuclear Agricultural Sciences of Ministry of Agriculture and Rural Affairs, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China.
Sci China Life Sci. 2025 Sep 5. doi: 10.1007/s11427-025-3032-x.
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.
日开花和闭花（DFOC）对水稻生殖发育和杂交育种至关重要，但其转录动态和潜在调控网络仍未得到充分表征。在这里，我们对浆片进行了高时间分辨率的转录组分析，以剖析两个粳稻品种的DFOC调控网络。差异表达基因（DEG）分析揭示了两个品种共有的核心基因，主要与茉莉酸（JA）信号传导和细胞壁重塑相关。通过整合DNA亲和纯化测序（DAP-seq），我们构建了由基本螺旋-环-螺旋转录因子（TF）OsMYC2介导的核心调控网络，该网络控制水稻中的DFOC。我们鉴定了木葡聚糖内转糖基酶相关基因1（OsXTR1），它编码一种细胞壁松弛酶，是DFOC期间由OsMYC2激活的关键基因。OsXTR1的破坏导致小花开放后无法闭合，证明了其在将细胞壁动态与激素调节联系起来方面的重要作用。同样，我们鉴定了一个JA生物合成基因，丙二烯氧化物环化酶（OsAOC），它通过OsMYC2介导的正反馈环参与DFOC。此外，我们开发了水稻DFOC数据库（http://zhoulab.zju.edu.cn/FT/index.html），提供对时空转录组、共表达网络和表型组学数据的交互式访问。总的来说，我们的研究揭示了一个以OsMYC2为中心的分层网络，该网络在DFOC期间协调JA信号传导和结构重塑，为优化水稻育种提供了机制见解和资源。
