TOR signaling is finely regulated under diverse abiotic stresses and may be required for the plant response with a different time-course depending on the duration and nature of the stress. Target of rapamycin (TOR) signaling is a central regulator of growth and development in eukaryotic organisms. However, its regulation under stress conditions has not yet been elucidated. In Arabidopsis, we show that TOR transcripts and activity in planta are finely regulated within hours after the onset of salt, osmotic, cold and oxidative stress. The expression of genes encoding the partner proteins of the TOR complex, RAPTOR3G and LST8-1, is also regulated. Besides, the data indicate that TOR activity increases at some time during the adverse condition. Interestingly, in oxidative stress, the major TOR activity increment occurred transiently at the early phase of treatment, while in salt, osmotic and cold stress, it was around 1 day after the unfavorable condition was applied. Those results suggest that the TOR signaling has an important role in the plant response to an exposure to stress. Moreover, basal ROS (H2O2) levels and their modification under abiotic stresses were altered in TOR complex mutants. On the other hand, the root phenotypic analysis of the effects caused by the diverse abiotic stresses on TOR complex mutants revealed that they were differently affected, being in some cases less sensitive, than wild-type plants to long-term unfavorable conditions. Therefore, in this work, we demonstrated that TOR signaling is tightly regulated under abiotic stresses, at transcript and activity level, with different and specific time-course patterns according to the type of abiotic stress in Arabidopsis. Taking our results together, we propose that TOR signaling should be necessary during the plant stress response.

中文翻译：

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雷帕霉素信号靶点在不同非生物胁迫下的植物反应中受到严格而不同的调控

TOR 信号在不同的非生物胁迫下受到精细调节，并且可能需要植物响应的不同时间进程，具体取决于胁迫的持续时间和性质。雷帕霉素 (TOR) 信号转导的靶标是真核生物生长和发育的中心调节剂。然而，其在压力条件下的调节尚未阐明。在拟南芥中，我们表明植物中的 TOR 转录物和活性在盐、渗透、冷和氧化应激开始后数小时内受到精细调节。编码 TOR 复合物伴侣蛋白 RAPTOR3G 和 LST8-1 的基因的表达也受到调节​​。此外，数据表明 TOR 活动在不利条件下的某个时间增加。有趣的是，在氧化应激中，主要的TOR活性增加在处理初期是短暂的，而在盐、渗透和冷胁迫下，是在不利条件施加后1天左右。这些结果表明，TOR 信号在植物对压力的反应中具有重要作用。此外，在 TOR 复合突变体中，基础 ROS (H2O2) 水平及其在非生物胁迫下的修饰发生了改变。另一方面，对不同非生物胁迫对 TOR 复合突变体造成的影响的根表型分析表明，与野生型植物相比，它们对长期不利条件的影响不同，在某些情况下不那么敏感。因此，在这项工作中，我们证明了 TOR 信号在非生物胁迫下受到严格调控，在转录和活性水平上，根据拟南芥中非生物胁迫的类型，具有不同和特定的时间进程模式。综合我们的结果，我们建议在植物应激反应期间应该需要 TOR 信号。