Seed dormancy, an essential trait for plant adaptation, is determined by the embryo itself and the surrounding tissues. Here, we found that rice (Oryza sativa) FERTILIZATION INDEPENDENT ENDOSPERM1 (OsFIE1) regulates endosperm-imposed dormancy and the dorsal aleurone thickness in a manner dependent on the parent of origin. Maternally expressed OsFIE1 suppresses gibberellin (GA) biosynthesis in the endosperm by depositing trimethylation of lysine 27 on histone H3 (H3K27me3) marks on GA biosynthesis-related genes, thus inhibiting germination and aleurone differentiation. Knockout of rice GA 20-oxidase1 (OsGA20ox1) alleviated the phenotypic defects in osfie1. The aleurone-positive determinant Crinkly 4 (OsCR4) is another target of the OsFIE1-containing Polycomb repressive complex 2 (PRC2). We found that OsFIE1 plays an important role in genomic imprinting in the endosperm of germinating seeds, particularly for paternally expressed genes associated with H3K27me3. The increased aleurone thickness of osfie1 substantially improved grain nutritional quality, indicating that the osfie1 gene may be utilized for breeding nutrient-enriched rice. The findings provide insights into the essential roles of PRC2-mediated H3K27me3 methylation in the acquisition of seed dormancy and endosperm cell differentiation in rice.

中文翻译：

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母系表达的 OsFERTILIZATION INDEPENDENT ENDOSPERM1 调节水稻种子休眠和糊粉酮发育


种子休眠是植物适应的基本特征，由胚胎本身和周围组织决定。在这里，我们发现水稻 （Oryza sativa） 不依赖受精ENDOSPERM1 （OsFIE1） 以取决于原源亲本的方式调节胚乳强加的休眠和背侧糊粉量。母系表达的 OsFIE1 通过将赖氨酸 27 的三甲基化沉积在 GA 生物合成相关基因上的组蛋白 H3 （H3K27me3） 标记上，从而抑制发芽和糊粉酮分化，从而抑制赤霉素 （GA） 在胚乳中的生物合成。敲除水稻 GA 20-氧化酶 1 （OsGA20ox1） 减轻了 osfie1 的表型缺陷。糊粉酮阳性决定簇 Crinkly 4 （OsCR4） 是含 OsFIE1 的多梳抑制复合物 2 （PRC2） 的另一个靶标。我们发现 OsFIE1 在发芽种子胚乳的基因组印记中起重要作用，特别是对于 H3K27me3 相关的父系表达基因。osfie1 糊粉烯厚度的增加显著改善了谷物营养品质，表明 osfie1 基因可用于培育营养丰富的水稻。这些发现为 PRC2 介导的 H3K27me3 甲基化在水稻种子休眠和胚乳细胞分化中的重要作用提供了见解。