Purpose

Hydrogen sulfide (H₂S) is an important signaling molecule in prokaryotes and eukaryotes. In higher plants, H₂S regulates different processes throughout development and stress responses. Here, we investigated the underlying mechanism of H₂S in modulating hypoxia response signaling in Arabidopsis.

Methods

DAB (3,3-diaminobenzidine) and fluorescent probes were used to detect the accumulation of reactive oxygen species and H₂S. Evans blue staining was conducted to observe the cell death. Quantitative RT-PCR was performed to measure the relative gene expression levels.

Results

Our data showed that endogenous H₂S production was induced by anoxia and appropriate application of exogenous H₂S mitigated the damage caused by submergence stress. Meanwhile, the histological staining, fluorescent microscope observation and molecular analysis demonstrated that H₂S metabolism-related mutants oasa1 and lcddes1-1 accumulated different ROS levels and exhibited different low oxygen sensitivities compared with the wild type. In addition, we observed that ER stress response genes were up-regulated in wild type upon anoxia, and different ER stress response-related mutants ero1-2, ero1-3, ero2-1, ero2-2 and bzip28bzip60 were more sensitive to submergence or anoxia than wild type. Moreover, the exogenous H₂S pretreatment could not alleviate submergence-induced leaf death in ero2-1 compared with wild type, indicating that hypoxia induced ER stress and activation of the unfolded protein response (UPR) signal pathway is important for plant hypoxia response.

Conclusion

Our work demonstrates that H₂S regulates hypoxic stress response through the integration with UPR. This study provides new insights into H₂S function during plant low oxygen stress response.

中文翻译：

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H2S 通过与拟南芥中未折叠蛋白反应的整合来调节低氧信号

目的

硫化氢 (H ₂ S) 是原核生物和真核生物中重要的信号分子。在高等植物中，H ₂ S 调节整个发育和胁迫反应的不同过程。在这里，我们研究了 H ₂ S 在调节拟南芥缺氧反应信号中的潜在机制。

方法

DAB(3,3-二氨基联苯胺)和荧光探针检测活性氧的积累和H ₂ S。进行伊文思蓝染色观察细胞死亡。进行定量RT-PCR以测量相对基因表达水平。

结果

我们的数据表明，内源性H ₂ S 的产生是由缺氧诱导的，外源性H ₂ S 的适当应用减轻了淹没应力造成的损害。同时，组织学染色、荧光显微镜观察和分子分析表明，与野生型相比，H ₂ S代谢相关突变体oasa1和lcddes1-1积累了不同的ROS水平，表现出不同的低氧敏感性。此外，我们观察到野生型缺氧时内质网应激反应基因上调，不同内质网应激反应相关突变体ero1-2、ero1-3、ero2-1、ero2-2和bzip28bzip60比野生型对淹没或缺氧更敏感。此外，与野生型相比，外源 H ₂ S 预处理不能减轻ero2-1淹没诱导的叶片死亡，表明缺氧诱导的 ER 应激和未折叠蛋白反应 (UPR) 信号通路的激活对植物缺氧反应很重要。

结论

我们的工作表明 H ₂ S 通过与 UPR 的整合来调节缺氧应激反应。这项研究为植物低氧胁迫响应过程中H ₂ S 的功能提供了新的见解。