Despite the importance of dormancy and dormancy cycling for plants’ fitness and life cycle phenology, a comprehensive characterization of the global and cellular epigenetic patterns across space and time in different seed dormancy states is lacking. Using Capsella bursa-pastoris (L.) Medik. (shepherd’s purse) seeds with primary and secondary dormancy, we investigated the dynamics of global genomic DNA methylation and explored the spatio-temporal distribution of 5-methylcytosine (5-mC) and histone H4 acetylated (H4Ac) epigenetic marks. Seeds were imbibed at 30 °C in a light regime to maintain primary dormancy, or in darkness to induce secondary dormancy. An ELISA-based method was used to quantify DNA methylation, in relation to total genomic cytosines. Immunolocalization of 5-mC and H4Ac within whole seeds (i.e., including testa) was assessed with reference to embryo anatomy. Global DNA methylation levels were highest in prolonged (14 days) imbibed primary dormant seeds, with more 5-mC marked nuclei present only in specific parts of the seed (e.g., SAM and cotyledons). In secondary dormant seeds, global methylation levels and 5-mC signal where higher at 3 and 7 days than 1 or 14 days. With respect to acetylation, seeds had fewer H4Ac marked nuclei (e.g., SAM) in deeper dormant states, for both types of dormancy. However, the RAM still showed signal after 14 days of imbibition under dormancy-inducing conditions, suggesting a central role for the radicle/RAM in the response to perceived ambient changes and the adjustment of the seed dormancy state. Thus, we show that seed dormancy involves extensive cellular remodeling of DNA methylation and H4 acetylation.

尽管休眠和休眠循环对植物的适应性和生命周期物候很重要，但缺乏对不同种子休眠状态下跨空间和时间的全球和细胞表观遗传模式的综合表征。使用荠菜(L.) 麦迪克。（牧羊人的钱包）种子具有初级和次级休眠，我们研究了全球基因组 DNA 甲基化的动态，并探索了 5-甲基胞嘧啶 (5-mC) 和组蛋白 H4 乙酰化 (H4Ac) 表观遗传标记的时空分布。种子在 30°C 光照条件下吸收以维持初级休眠，或在黑暗中吸收以诱导次级休眠。基于 ELISA 的方法用于量化与总基因组胞嘧啶相关的 DNA 甲基化。参考胚胎解剖学评估了整个种子（即，包括种皮）内 5-mC 和 H4Ac 的免疫定位。在长时间（14 天）吸收的初级休眠种子中，全球 DNA 甲基化水平最高，更多的 5-mC 标记的细胞核仅存在于种子的特定部分（例如，SAM 和子叶）。在次生休眠种子中，整体甲基化水平和 5-mC 信号在第 3 天和第 7 天高于第 1 天或第 14 天。关于乙酰化，对于两种休眠类型，种子在更深的休眠状态下具有较少的 H4Ac 标记核（例如，SAM）。然而，在诱导休眠的条件下，RAM 在 14 天的吸收后仍然显示出信号，这表明胚根/RAM 在响应感知的环境变化和种子休眠状态的调整中发挥着核心作用。因此，我们表明种子休眠涉及 DNA 甲基化和 H4 乙酰化的广泛细胞重塑。RAM 在诱导休眠的条件下吸水 14 天后仍显示出信号，这表明胚根/ RAM 在响应感知的环境变化和调整种子休眠状态方面发挥着核心作用。因此，我们表明种子休眠涉及 DNA 甲基化和 H4 乙酰化的广泛细胞重塑。RAM 在诱导休眠的条件下吸水 14 天后仍显示出信号，这表明胚根/ RAM 在响应感知的环境变化和调整种子休眠状态方面发挥着核心作用。因此，我们表明种子休眠涉及 DNA 甲基化和 H4 乙酰化的广泛细胞重塑。