Peng Jing, Zhang Qi, Tang Li Ping, Xu Biao Jie, Laux Thomas, Zhang Xian Sheng, Su Ying Hua
National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, China.
Sino-German Joint Research Center on Agricultural Biology, Shandong Agricultural University, Tai'an, Shandong, China.
Nat Commun. 2025 May 6;16(1):4185. doi: 10.1038/s41467-025-59335-8.
Many plant species can develop embryos from somatic cells without fertilization. During this process, known as somatic embryogenesis, changes in the DNA methylation patterns are characteristic of reprogramming somatic cells into an embryogenic state. However, the underlying mechanisms connecting DNA methylation and activating totipotency-regulating genes have remained largely unknown. Here, we show that during somatic embryogenesis induced by overexpressing the totipotency-regulating transcription factor LEAFY COTYLEDON2 (LEC2) in Arabidopsis, CHH hypermethylation is deposited by the LEC2-activated RNA-directed DNA methylation (RdDM) pathway. A reader complex composed of SU(VAR)3-9 HOMOLOGS (SUVH) and its chaperone SUVH-INTERACTING DNAJ DOMAIN-CONTAINING PROTEIN (SDJ) binds to the CHH hypermethylated regions and recruits AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED (AHL) chromatin modification proteins to increase chromatin accessibility, resulting in the transcriptional activation of totipotency-regulating genes. Our work reveals a molecular framework of how epigenetic modifications mediate somatic cell reprogramming, offering a pathway toward enhancing somatic embryogenesis in agricultural regeneration biology.
许多植物物种可以在未受精的情况下从体细胞发育出胚胎。在这个被称为体细胞胚胎发生的过程中，DNA甲基化模式的变化是将体细胞重编程为胚性状态的特征。然而，连接DNA甲基化和激活全能性调控基因的潜在机制在很大程度上仍然未知。在这里，我们表明，在拟南芥中通过过表达全能性调控转录因子LEAFY COTYLEDON2（LEC2）诱导体细胞胚胎发生的过程中，CHH超甲基化是由LEC2激活的RNA指导的DNA甲基化（RdDM）途径沉积的。由SU（VAR）3-9同源物（SUVH）及其伴侣SUVH相互作用DNAJ结构域包含蛋白（SDJ）组成的读取复合物与CHH超甲基化区域结合，并招募含AT钩基序的核定位（AHL）染色质修饰蛋白，以增加染色质可及性，从而导致全能性调控基因的转录激活。我们的工作揭示了表观遗传修饰介导体细胞重编程的分子框架，为农业再生生物学中增强体细胞胚胎发生提供了一条途径。
