Fig ( L.) with purple-red peel cultivars are popular among consumers and exhibit better storability. While DNA methylation influences fruit ripening and color development, its specific role in fig fruit remains unclear. This study explores the impact of DNA methylation on the fig peel coloration. Enzymatic colorimetric detection revealed that the level of ‘Purple Peel’ fig DNA methylation decreases with fig fruit ripening and coloring. Treatment of young fruit with the DNA-methylation inhibitor azacytidine induced peel coloration, suggesting that a decrease in DNA-methylation level promotes fig peel coloration. Seven members of DNA methyltransferases and three members of DNA demethylases were identified from a high-level fig genome, highlighting FcMET1 and FcDRM2 as stable proteins, ensuring functional expression. Reference to the protein interaction network map predicted that FcMET1 is in a central position, suggesting a crucial regulatory role in multiple biological processes. Correlation analysis revealed a positive correlation between expression during peel development and the level of total DNA methylation. Weighted gene co-expression network analysis identified co-expression of with the color-related transcription factors , and , as well as with eight structural genes in the flavonoid-biosynthesis pathway. The expression of was negatively correlated with that of . McrBC-PCR and Bisulfite Sequencing detection showed that a low methylation level of the promoter corresponds with its high expression in colored fig. This investigation of the mechanism of DNA methylation provides a theoretical basis for understanding the role of DNA-methylation modifications in fig ripening and coloring.

中文翻译：

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FcMET1 介导低 DNA 甲基化并促进无花果果皮着色


紫红色果皮品种的无花果（L.）深受消费者喜爱，且耐贮性较好。虽然 DNA 甲基化会影响果实的成熟和颜色的形成，但它在无花果果实中的具体作用仍不清楚。本研究探讨 DNA 甲基化对无花果皮颜色的影响。酶比色检测表明，“紫皮”无花果 DNA 甲基化水平随着无花果果实的成熟和着色而降低。用 DNA 甲基化抑制剂氮胞苷处理幼果可诱导果皮着色，表明 DNA 甲基化水平的降低促进无花果果皮着色。从高水平无花果基因组中鉴定出 7 个 DNA 甲基转移酶成员和 3 个 DNA 去甲基化酶成员，突出显示 FcMET1 和 FcDRM2 是稳定的蛋白质，确保功能表达。参考蛋白质相互作用网络图预测FcMET1处于中心位置，表明在多种生物过程中发挥着至关重要的调节作用。相关分析显示果皮发育过程中的表达与总 DNA 甲基化水平呈正相关。加权基因共表达网络分析确定了 与颜色相关转录因子 、 和 以及与类黄酮生物合成途径中的八个结构基因的共表达。的表达量与 的表达量呈负相关。 McrBC-PCR和亚硫酸氢盐测序检测表明，彩色无花果中启动子的低甲基化水平与其高表达相对应。这项对 DNA 甲基化机制的研究为理解 DNA 甲基化修饰在无花果成熟和着色中的作用提供了理论基础。