The biological purpose of plant stem cells is to maintain themselves while providing new pools of differentiated cells that form organs and rejuvenate or replace damaged tissues. Protein homeostasis, or proteostasis, is required for cell function and viability. However, the link between proteostasis and plant stem cell identity remains unknown. In contrast to their differentiated counterparts, we find that root stem cells can prevent the accumulation of aggregated proteins even under proteotoxic stress conditions such as heat stress or proteasome inhibition. Notably, root stem cells exhibit enhanced expression of distinct chaperones that maintain proteome integrity. Particularly, intrinsic high levels of the TRiC/CCT chaperonin determine stem cell maintenance and their remarkable ability to suppress protein aggregation. Overexpression of CCT8, a key activator of TRiC/CCT assembly, is sufficient to ameliorate protein aggregation in differentiated cells and confer resistance to proteotoxic stress in plants. Taken together, our results indicate that enhanced proteostasis mechanisms in stem cells could be an important requirement for plants to persist under extreme environmental conditions and reach extreme long ages. Thus, proteostasis of stem cells could provide insights to design and breed plants tolerant to environmental challenges caused by the climate change.

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拟南芥干细胞的内在伴侣网络赋予针对蛋白毒性应激的保护

植物干细胞的生物学目的是维持自身状态，同时提供新的分化细胞库，这些细胞形成器官并恢复或替换受损的组织。蛋白质稳态或蛋白稳态是细胞功能和生存能力所必需的。然而，蛋白稳态和植物干细胞特性之间的联系仍然未知。与它们分化的对应物相反，我们发现，即使在蛋白毒性胁迫条件下，例如热胁迫或蛋白酶体抑制作用下，根干细胞也可以防止聚集蛋白的积累。值得注意的是，根干细胞表现出增强的独特伴侣蛋白的表达，从而维持蛋白质组的完整性。特别是，TRiC / CCT伴侣蛋白的内在高水平决定了干细胞的维持及其抑制蛋白质聚集的显着能力。CCT8的过度表达 TRiC / CCT装配的关键激活因子足以改善分化细胞中的蛋白质聚集，并赋予植物抗蛋白毒性胁迫的能力。两者合计，我们的结果表明，增强干细胞中的蛋白质稳态机制可能是植物在极端环境条件下生存并达到极长寿命的重要要求。因此，干细胞的蛋白质稳态可以为设计和育种耐气候变化引起的环境挑战的植物提供见识。我们的结果表明，增强干细胞的蛋白质稳态机制可能是植物在极端环境条件下生存并达到极长寿命的重要要求。因此，干细胞的蛋白质稳态可以为设计和育种耐气候变化引起的环境挑战的植物提供见识。我们的结果表明，增强干细胞的蛋白质稳态机制可能是植物在极端环境条件下生存并达到极长寿命的重要要求。因此，干细胞的蛋白质稳态可以为设计和育种耐气候变化引起的环境挑战的植物提供见识。