Maize develops separate ear and tassel inflorescences with initially similar morphology but ultimately different architecture and sexuality. The detailed regulatory mechanisms underlying these changes still remain largely unclear. In this study, through analyzing the time-course meristem transcriptomes and floret single-cell transcriptomes of ear and tassel, we revealed the regulatory dynamics and pathways underlying inflorescence development and sex differentiation. We identified 16 diverse gene clusters with differential spatiotemporal expression patterns and revealed biased regulation of redox, programmed cell death, and hormone signals during meristem differentiation between ear and tassel. Notably, based on their dynamic expression patterns, we revealed the roles of two RNA-binding proteins in regulating inflorescence meristem activity and axillary meristem formation. Moreover, using the transcriptional profiles of 53 910 single cells, we uncovered the cellular heterogeneity between ear and tassel florets. We found that multiple signals associated with either enhanced cell death or reduced growth are responsible for tassel pistil suppression, while part of the gibberellic acid signal may act non-cell-autonomously to regulate ear stamen arrest during sex differentiation. We further showed that the pistil-protection gene () functions antagonistically to the known pistil-suppression genes through regulating common molecular pathways, and constructed a regulatory network for pistil-fate determination. Collectively, our study provides a deep understanding of the regulatory mechanisms underlying inflorescence development and sex differentiation in maize, laying the foundation for identifying new regulators and pathways for maize hybrid breeding and improvement.

中文翻译：

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渐进分生组织和单细胞转录组揭示了玉米花序发育和性别分化的调控机制


玉米发育出独立的穗花序和雄穗花序，最初具有相似的形态，但最终具有不同的结构和性。这些变化背后的详细监管机制仍然很大程度上不清楚。在本研究中，通过分析穗和雄穗的时程分生组织转录组和小花单细胞转录组，我们揭示了花序发育和性别分化的调控动态和途径。我们鉴定了 16 个具有差异时空表达模式的不同基因簇，并揭示了穗和雄穗分生组织分化过程中氧化还原、程序性细胞死亡和激素信号的偏向调节。值得注意的是，根据它们的动态表达模式，我们揭示了两种RNA结合蛋白在调节花序分生组织活性和腋生分生组织形成中的作用。此外，利用 53 910 个单细胞的转录谱，我们发现了穗花和雄穗花之间的细胞异质性。我们发现与细胞死亡增强或生长减少相关的多个信号导致雄蕊雌蕊抑制，而部分赤霉酸信号可能非细胞自主地发挥作用，以调节性别分化过程中耳雄蕊的停滞。我们进一步表明，雌蕊保护基因（）通过调节共同的分子途径与已知的雌蕊抑制基因发挥拮抗作用，并构建了雌蕊命运决定的调控网络。总的来说，我们的研究深入了解了玉米花序发育和性别分化的调控机制，为确定玉米杂交育种和改良的新调控因子和途径奠定了基础。