Dual regulations of cell cycle regulator DPa by auxin in Arabidopsis root distal stem cell maintenance.

Junxia Wang, Xiaoxuan Li, Xiaolu Chen, Wenxin Tang, Zipeng Yu, Tongda Xu, Huiyu Tian, Zhaojun Ding

Proceedings of the National Academy of Sciences of the United States of America 2023 May 09

filter terms:

The plant hormone auxin plays a key role to maintain root stem cell identity which is essential for root development. However, the molecular mechanism by which auxin regulates root distal stem cell (DSC) identity is not well understood. In this study, we revealed that the cell cycle factor DPa is a vital regulator in the maintenance of root DSC identity through multiple auxin signaling cascades. On the one hand, auxin positively regulates the transcription of DPa via AUXIN RESPONSE FACTOR 7 and ARF19. On the other hand, auxin enhances the protein stability of DPa through MITOGEN-ACTIVATED PROTEIN KINASE 3 (MPK3)/MPK6-mediated phosphorylation. Consistently, mutation of the identified three threonine residues (Thr10, Thr25, and Thr227) of DPa to nonphosphorylated form alanine (DPa3A) highly decreased the phosphorylation level of DPa, which decreased its protein stability and affected the maintenance of root DSC identity. Taken together, this study provides insight into the molecular mechanism of how auxin regulates root distal stem cell identity through the dual regulations of DPa at both transcriptional and posttranslational levels.

Citation

Junxia Wang, Xiaoxuan Li, Xiaolu Chen, Wenxin Tang, Zipeng Yu, Tongda Xu, Huiyu Tian, Zhaojun Ding. Dual regulations of cell cycle regulator DPa by auxin in Arabidopsis root distal stem cell maintenance. Proceedings of the National Academy of Sciences of the United States of America. 2023 May 09;120(19):e2218503120