Local induction of IAA5 and IAA29 promotes DNA damage-triggered stem cell death in Arabidopsis roots
Local induction of IAA5 and IAA29 promotes DNA damage-triggered stem cell death in Arabidopsis roots
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DOI：
10.1101/2022.09.02.506394
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发表时间：
2022-09
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影响因子：
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通讯作者：
Naoki Takahashi;Nobuo Ogita;Toshiya Koike;K. Nishimura;Soichi Inagaki;M. Umeda
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文献类型：
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作者：
Naoki Takahashi;Nobuo Ogita;Toshiya Koike;K. Nishimura;Soichi Inagaki;M. Umeda
植物在胚后发育过程中不断产生器官，因此如何在不断变化的环境中保存干细胞对它们的生存至关重要。基因毒性胁迫威胁着所有体细胞的基因组稳定性，而在分生组织中，只有干细胞因DNA损伤而发生细胞死亡，然后进行干细胞补充。以前的研究表明，抑制生长素在根中向下流动参与DNA损伤诱导的干细胞死亡;然而，细胞死亡如何局限于生长素含量减少的组织中的干细胞仍然难以捉摸。在这里，我们表明，在响应DNA双链断裂，Aux/IAA家族成员IAA 5和IAA 29，编码生长素信号的负调节，在拟南芥根的血管干细胞和他们的女儿，本地诱导。这是一种对DNA损伤的主动反应，其中转录因子γ反应1的供应因子直接诱导其表达。在iaa 5 iaa 29双突变体中，DNA损伤诱导的干细胞死亡被显著抑制，而在血管干细胞中稳定形式的IAA 5的表达使其完全恢复。我们的遗传数据显示，生长素信号的抑制和生长素含量的降低是细胞死亡诱导的先决条件，这表明在维持干细胞基因组完整性方面的核心作用。IAA 5和IAA 29的诱导促进DNA胁迫下拟南芥根中的干细胞死亡。
Plants generate organs continuously during post-embryonic development, thus how to preserve stem cells in changing environments is crucial for their survival. Genotoxic stress threatens genome stability in all somatic cells, whereas, in the meristem, only stem cells undergo cell death in response to DNA damage, followed by stem cell replenishment. It was previously shown that inhibition of downward auxin flow in roots participates in DNA damage-induced stem cell death; however, how cell death is confined to stem cells in tissues with reduced auxin content remains elusive. Here we show that, in response to DNA double-strand breaks, the Aux/IAA family members IAA5 and IAA29, which encode the negative regulators of auxin signaling, were locally induced in vascular stem cells and their daughters in Arabidopsis roots. This is an active response to DNA damage in which the transcription factor SUPPRESSOR OF GAMMA RESPONSE 1 directly induces their expression. In the iaa5 iaa29 double mutant, DNA damage-induced stem cell death was significantly suppressed, while it was fully restored by the expression of a stable form of IAA5 in vascular stem cells. Our genetic data revealed that both the suppression of auxin signaling and reduced auxin content are prerequisite for cell death induction, suggesting the central role in maintaining genome integrity in stem cells. One-sentence summary The induction of IAA5 and IAA29 promotes stem cell death in Arabidopsis roots under DNA stress.