Morphological, genic and epigenetic differences often exist in separate sexes of dioecious and trioecious plants. However, the connections and relationships among them in different breeding systems are still unclear. Papaya has three sex types, which is genetically determined and epigenetically regulated, and was chosen as a model to study sex differentiation. Bisulfite sequencing of genomic DNA extracted from early-stage flowers revealed sex-specific genomic methylation landscapes and seasonally methylome reprogramming processes in dioecious and gynodioecious papaya grown in spring and summer. Extensive methylation of sex-determining region (SDR) was the distinguishing epigenetic characteristics of nascent XY sex chromosomes in papaya. Seasonal methylome reprogramming of early-stage flowers in both dioecy and gynodioecy systems were detected, resulting from transcriptional expression pattern alterations of methylation-modification-related and chromatin-remodeling-related genes, particularly from those genes involved in active demethylation. Genes involved in phytohormone signal transduction pathway in male flowers have played an important role in the formation of male-specific characteristics. These findings enhanced the understanding of the genetic and epigenetic contributions to sex differentiation and the complexity of sex chromosome evolution in trioecious plants.

中文翻译：

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甲基化相关基因影响雌雄异株和雌雄异株番木瓜的性别分化。

形态学、基因和表观遗传差异通常存在于雌雄异株和三雌雄异株植物的不同性别中。然而，它们在不同育种系统中的联系和关系仍不清楚。木瓜具有三种性别类型，由基因决定和表观遗传调节，并被选为研究性别分化的模型。从早期花朵中提取的基因组 DNA 的亚硫酸氢盐测序揭示了春季和夏季生长的雌雄异株和雌雄异株番木瓜的性别特异性基因组甲基化景观和季节性甲基化组重编程过程。性别决定区 (SDR) 的广泛甲基化是木瓜中新生 XY 性染色体的显着表观遗传特征。检测到雌雄异株和雌雄异株系统中早期花朵的季节性甲基化重编程，由甲基化修饰相关和染色质重塑相关基因的转录表达模式改变引起，特别是来自那些参与主动去甲基化的基因。参与雄花植物激素信号转导通路的基因在雄性花特异性特征的形成中发挥了重要作用。这些发现增强了对三株植物性别分化和性染色体进化复杂性的遗传和表观遗传贡献的理解。参与雄花植物激素信号转导通路的基因在雄性花特异性特征的形成中发挥了重要作用。这些发现增强了对三株植物性别分化和性染色体进化复杂性的遗传和表观遗传贡献的理解。参与雄花植物激素信号转导通路的基因在雄性花特异性特征的形成中发挥了重要作用。这些发现增强了对三株植物性别分化和性染色体进化复杂性的遗传和表观遗传贡献的理解。