State Key Laboratory of Plant Genomics and Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
New Phytol. 2018 Apr;218(2):789-803. doi: 10.1111/nph.15017. Epub 2018 Feb 26.
In angiosperms, the key step in sexual reproduction is successful acquisition of meiotic fate. However, the molecular mechanism determining meiotic fate remains largely unknown. Here, we report that OsSPOROCYTELESS (OsSPL) is critical for meiotic entry in rice (Oryza sativa). We performed a large-scale genetic screen of rice sterile mutants aimed to identify genes regulating meiotic entry and identified OsSPL using map-based cloning. We showed that meiosis-specific callose deposition, chromatin organization, and centromere-specific histone H3 loading were altered in the cells corresponding to pollen mother cells in Osspl anthers. Global transcriptome analysis showed that the enriched differentially expressed genes in Osspl were mainly related to redox status, meiotic process, and parietal cell development. OsSPL might form homodimers and interact with TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factor OsTCP5 via the SPL dimerization and TCP interaction domain. OsSPL also interacts with TPL (TOPLESS) corepressors, OsTPL2 and OsTPL3, via the EAR motif. Our results suggest that the OsSPL-mediated signaling pathway plays a crucial role in rice meiotic entry, which appears to be a conserved regulatory mechanism for meiotic fate acquisition in angiosperms.
在被子植物中，有性生殖的关键步骤是成功获得减数分裂命运。然而，决定减数分裂命运的分子机制在很大程度上仍然未知。在这里，我们报告 OsSPOROCYTELESS（OsSPL）在水稻（Oryza sativa）减数分裂进入中是至关重要的。我们进行了大规模的水稻不育突变体遗传筛选，旨在鉴定调控减数分裂进入的基因，并使用基于图谱的克隆方法鉴定 OsSPL。我们表明，在 Osspl 花药中花粉母细胞对应的细胞中，减数分裂特异性胼胝质沉积、染色质组织和着丝粒特异性组蛋白 H3 加载发生改变。全转录组分析表明，Osspl 中富集的差异表达基因主要与氧化还原状态、减数分裂过程和壁细胞发育有关。OsSPL 可能形成同源二聚体，并通过 SPL 二聚体和 TCP 相互作用域与 TEOSINTE BRANCHED1/CYCLOIDEA/PCF（TCP）转录因子 OsTCP5 相互作用。OsSPL 还通过 EAR 基序与 TOPLESS（TPL）核心抑制子 OsTPL2 和 OsTPL3 相互作用。我们的结果表明，OsSPL 介导的信号通路在水稻减数分裂进入中起着至关重要的作用，这似乎是被子植物获得减数分裂命运的保守调控机制。
