DNA methylation is a crucial regulatory mechanism in many biological processes. However, limited studies have dissected the contribution of DNA methylation to sexual differentiation in dioecious plants. In this study, we investigated the variances in methylation and transcriptional patterns of male and female flowers of garden asparagus. Compared with male flowers, female flowers at the same stages showed higher levels of DNA methylation. Both male and female flowers gained DNA methylation globally from the premeiotic to meiotic stages. Detailed analysis revealed that the increased DNA methylation was largely due to increased CHH methylation. Correlation analysis of differentially expressed genes and differentially methylated regions suggested that DNA methylation might not have contributed to the expression variation of the sex-determining genes SOFF and TDF1 but probably played important roles in sexual differentiation and flower development of garden asparagus. The upregulated genes AoMS1, AoLAP3, AoAMS, and AoLAP5 with varied methylated CHH regions might have been involved in sexual differentiation and flower development of garden asparagus. Plant hormone signaling genes and transcription factor genes also participated in sexual differentiation and flower development with potential epigenetic regulation. In addition, the CG and CHG methylation levels in the Y chromosome were notably higher than those in the X chromosome, implying that DNA methylation might have been involved in Y chromosome evolution. These data provide insights into the epigenetic modification of sexual differentiation and flower development and improve our understanding of sex chromosome evolution in garden asparagus.

中文翻译：

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DNA甲基化参与雌雄异株植物园芦笋的性分化和性染色体进化

DNA甲基化是许多生物过程中的关键调控机制。然而，有限的研究已经剖析了 DNA 甲基化对雌雄异株植物有性分化的贡献。在这项研究中，我们调查了花园芦笋雄花和雌花甲基化和转录模式的差异。与雄花相比，同一时期的雌花DNA甲基化水平更高。从减数分裂前到减数分裂阶段，雄花和雌花都在全球范围内获得了 DNA 甲基化。详细分析显示 DNA 甲基化增加主要是由于 CHH 甲基化增加。差异表达基因和差异甲基化区域的相关分析表明，DNA甲基化可能对性别决定基因的表达变异没有贡献。关闭和TDF1但可能在园林芦笋的性分化和开花发育中起重要作用。上调基因AOMS1,AOLAP3,AOAMS， 和AOLAP5不同甲基化的 CHH 区域可能参与了花园芦笋的性分化和花发育。植物激素信号基因和转录因子基因也参与了具有潜在表观遗传调控的性分化和花发育。此外，Y染色体中的CG和CHG甲基化水平明显高于X染色体，这表明DNA甲基化可能参与了Y染色体的进化。这些数据提供了对性分化和花发育的表观遗传修饰的见解，并提高了我们对花园芦笋性染色体进化的理解。