Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing 100039, China.
Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
Curr Biol. 2024 Nov 18;34(22):5187-5196.e3. doi: 10.1016/j.cub.2024.09.052. Epub 2024 Oct 21.
The root system of a plant is essential for plant growth and development because it absorbs nutrients and water from the soil. The root stem cells are maintained and replenished by the quiescent center and are essential for the formation of the specific root structure. In Arabidopsis, the WUSCHEL-RELATED HOMEOBOX 5 (WOX5) plays a key role in regulating root stem cell fate. However, which factor can directly modulate the stability of WOX5 protein remains totally unknown. Here, we report that the peptidase DA1 (LARGE IN CHINESE) interacts with and cleaves WOX5, resulting in the destabilization of WOX5. Genetic analyses support that DA1 acts through WOX5 to regulate root stem cell function. We further demonstrate that cytokinin (CK) signaling induces the accumulation of DA1 protein, thereby decreasing the abundance of WOX5 protein in the root. Consistent with these results, the mutation in DA1 increases the layers of columella stem cells and influences CK-induced differentiation of columella stem cells. Thus, our results reveal a previously unrecognized mechanism by which the cleavage of WOX5 by DA1 connects CK signaling and root stem cell function in Arabidopsis.
植物的根系对于植物的生长和发育至关重要，因为它从土壤中吸收养分和水分。根干细胞由静止中心维持和补充，对于形成特定的根结构至关重要。在拟南芥中，WUSCHEL-RELATED HOMEOBOX 5（WOX5）在调节根干细胞命运方面发挥着关键作用。然而，哪个因素可以直接调节 WOX5 蛋白的稳定性仍然完全未知。在这里，我们报告肽酶 DA1（LARGE IN CHINESE）与 WOX5 相互作用并切割它，导致 WOX5 的不稳定性。遗传分析支持 DA1 通过 WOX5 来调节根干细胞功能。我们进一步证明细胞分裂素（CK）信号诱导 DA1 蛋白的积累，从而减少根中 WOX5 蛋白的丰度。与这些结果一致，DA1 的突变增加了柱状茎细胞的层数，并影响 CK 诱导的柱状茎细胞分化。因此，我们的结果揭示了一个以前未被认识的机制，即 DA1 通过切割 WOX5 将 CK 信号与拟南芥中的根干细胞功能联系起来。
