Aix Marseille Université, UMR7265 CNRS, CEA, Institut de Biosciences et de Biotechnologies d'Aix-Marseille (BIAM), CEA/Cadarache, Saint-Paul-lez-Durance, France.
IRSN, Service de Radioprotection des Populations et de l'Environnement (SERPEN), MICADOLab, CEA/Cadarache, Saint-Paul-lez-Durance, France.
Plant Cell Environ. 2024 Oct;47(10):3882-3898. doi: 10.1111/pce.14994. Epub 2024 Jun 3.
Ionising γ radiation produces reactive oxygen species by water radiolysis, providing an interesting model approach for studying oxidative stress in plants. Three-week old plants of Arabidopsis thaliana were exposed to a low dose rate (25 mGy h) of γ radiation for up to 21 days. This treatment had no effect on plant growth and morphology, but it induced chronic oxidation of lipids which was associated with an accumulation of reactive carbonyl species (RCS). However, contrary to lipid peroxidation, lipid RCS accumulation was transient only, being maximal after 1 day of irradiation and decreasing back to the initial level during the subsequent days of continuous irradiation. This indicates the induction of a carbonyl-metabolising process during chronic ionising radiation. Accordingly, the γ-radiation treatment induced the expression of xenobiotic detoxification-related genes (AER, SDR1, SDR3, ALDH4, and ANAC102). The transcriptomic response of some of those genes (AER, SDR1, and ANAC102) was deregulated in the tga256 mutant affected in three TGAII transcription factors, leading to enhanced and/or prolonged accumulation of RCS and to a marked inhibition of plant growth during irradiation compared to the wild type. These results show that Arabidopsis is able to acclimate to chronic oxidative stress and that this phenomenon requires activation of a carbonyl detoxification mechanism controlled by TGAII. This acclimation did not occur when plants were exposed to an acute γ radiation stress (100 Gy) which led to persistent accumulation of RCS and marked inhibition of plant growth. This study shows the role of secondary products of lipid peroxidation in the detrimental effects of reactive oxygen species.
电离γ辐射通过水的辐射分解产生活性氧物质，为研究植物中的氧化应激提供了一个有趣的模型方法。将拟南芥（Arabidopsis thaliana）三叶期植物暴露于低剂量率（25 mGy h）γ辐射下长达 21 天。这种处理方式对植物的生长和形态没有影响，但会诱导脂质的慢性氧化，这与活性羰基物质（RCS）的积累有关。然而，与脂质过氧化不同，脂质 RCS 的积累是短暂的，在辐照后 1 天达到最大值，并在随后的连续辐照天内回落到初始水平。这表明在慢性电离辐射下诱导了羰基代谢过程。因此，γ辐射处理诱导了外源解毒相关基因（AER、SDR1、SDR3、ALDH4 和 ANAC102）的表达。其中一些基因（AER、SDR1 和 ANAC102）的转录组反应在影响三个 TGAII 转录因子的 tga256 突变体中被扰乱，导致 RCS 的积累增强和/或延长，并在辐照期间与野生型相比显著抑制植物生长。这些结果表明，拟南芥能够适应慢性氧化应激，并且这种现象需要 TGAII 控制的羰基解毒机制的激活。当植物暴露于 100 Gy 的急性γ辐射应激时，这种适应不会发生，这会导致 RCS 的持续积累和植物生长的显著抑制。这项研究表明了脂质过氧化的次级产物在活性氧物质的有害影响中的作用。
