Commissariat à l'Energie Atomique et aux Energies Alternatives, Direction des Sciences du Vivant, Institut de Biologie Environementale et de Biotechnologies, Laboratoire d'Ecophysiologie Moléculaire des Plantes, F-13108 Saint-Paul-lez-Durance, France.
Plant Cell. 2013 Apr;25(4):1445-62. doi: 10.1105/tpc.113.109827. Epub 2013 Apr 16.
Singlet oxygen (¹O₂) is a reactive oxygen species that can function as a stress signal in plant leaves leading to programmed cell death. In microalgae, ¹O₂-induced transcriptomic changes result in acclimation to ¹O₂. Here, using a chlorophyll b-less Arabidopsis thaliana mutant (chlorina1 [ch1]), we show that this phenomenon can also occur in vascular plants. The ch1 mutant is highly photosensitive due to a selective increase in the release of ¹O₂ by photosystem II. Under photooxidative stress conditions, the gene expression profile of ch1 mutant leaves very much resembled the gene responses to ¹O₂ reported in the Arabidopsis mutant flu. Preexposure of ch1 plants to moderately elevated light intensities eliminated photooxidative damage without suppressing ¹O₂ formation, indicating acclimation to ¹O₂. Substantial differences in gene expression were observed between acclimation and high-light stress: A number of transcription factors were selectively induced by acclimation, and contrasting effects were observed for the jasmonate pathway. Jasmonate biosynthesis was strongly induced in ch1 mutant plants under high-light stress and was noticeably repressed under acclimation conditions, suggesting the involvement of this hormone in ¹O₂-induced cell death. This was confirmed by the decreased tolerance to photooxidative damage of jasmonate-treated ch1 plants and by the increased tolerance of the jasmonate-deficient mutant delayed-dehiscence2.
单线态氧（¹O₂）是一种活性氧物质，可作为植物叶片中的应激信号，导致程序性细胞死亡。在微藻中，¹O₂诱导的转录组变化导致对¹O₂的适应。在这里，我们使用叶绿素 b 缺失的拟南芥突变体（chlorina1 [ch1]）表明，这种现象也可能发生在维管植物中。由于光系统 II 选择性地增加了 ¹O₂的释放，ch1 突变体对光非常敏感。在光氧化应激条件下，ch1 突变体叶片的基因表达谱与在拟南芥突变体 flu 中报道的对 ¹O₂的基因反应非常相似。ch1 植物预先暴露于适度升高的光强度下可消除光氧化损伤，而不会抑制 ¹O₂的形成，表明对 ¹O₂的适应。适应和高光胁迫之间观察到明显的基因表达差异：一些转录因子被适应选择性诱导，而茉莉酸途径则观察到相反的作用。在高光胁迫下，ch1 突变体植物中茉莉酸生物合成强烈诱导，而在适应条件下明显受到抑制，表明该激素参与 ¹O₂诱导的细胞死亡。这通过用茉莉酸处理的 ch1 植物对光氧化损伤的耐受性降低以及茉莉酸缺陷突变体延迟裂爿 2 的耐受性增加得到证实。
