Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan.
Center for Sustainable Resource Science, RIKEN, Yokohama 230-0045, Japan.
Plant Cell. 2022 Oct 27;34(11):4348-4365. doi: 10.1093/plcell/koac218.
Plant cells exhibit remarkable plasticity of their differentiation states, enabling regeneration of whole plants from differentiated somatic cells. How they revert cell fate and express pluripotency, however, remains unclear. In this study, we demonstrate that transcriptional activation of auxin biosynthesis is crucial for reprogramming differentiated Arabidopsis (Arabidopsis thaliana) leaf cells. Our data show that interfering with the activity of histone acetyltransferases dramatically reduces callus formation from leaf mesophyll protoplasts. Histone acetylation permits transcriptional activation of PLETHORAs, leading to the induction of their downstream YUCCA1 gene encoding an enzyme for auxin biosynthesis. Auxin biosynthesis is in turn required to accomplish initial cell division through the activation of G2/M phase genes mediated by MYB DOMAIN PROTEIN 3-RELATED (MYB3Rs). We further show that the AUXIN RESPONSE FACTOR 7 (ARF7)/ARF19 and INDOLE-3-ACETIC ACID INDUCIBLE 3 (IAA3)/IAA18-mediated auxin signaling pathway is responsible for cell cycle reactivation by transcriptionally upregulating MYB3R4. These findings provide a mechanistic model of how differentiated plant cells revert their fate and reinitiate the cell cycle to become pluripotent.
植物细胞表现出其分化状态的显著可塑性，使它们能够从分化的体细胞中再生出整株植物。然而，它们如何逆转细胞命运并表达多能性仍然不清楚。在这项研究中，我们证明了生长素生物合成的转录激活对于重编程分化的拟南芥（Arabidopsis thaliana）叶片细胞是至关重要的。我们的数据表明，干扰组蛋白乙酰转移酶的活性会显著减少叶片原生质体愈伤组织的形成。组蛋白乙酰化允许 PLETHORAs 的转录激活，导致其下游编码生长素生物合成酶的 YUCCA1 基因的诱导。生长素生物合成反过来又需要通过 MYB DOMAIN PROTEIN 3-RELATED (MYB3Rs) 介导的 G2/M 期基因的激活来完成初始细胞分裂。我们进一步表明，AUXIN RESPONSE FACTOR 7 (ARF7)/ARF19 和 INDOLE-3-ACETIC ACID INDUCIBLE 3 (IAA3)/IAA18 介导的生长素信号通路通过转录上调 MYB3R4 负责细胞周期的重新激活。这些发现提供了一个机制模型，说明分化的植物细胞如何逆转其命运并重新启动细胞周期以成为多能性的。
