Institute of Biology, Applied Genetics, Dahlem Centre of Plant Sciences, Freie Universität Berlin, D-14195 Berlin, Germany; Botany and Microbiology Department, Faculty of Science, Cairo University, 12613 Giza, Egypt.
Institute of Biology, Applied Genetics, Dahlem Centre of Plant Sciences, Freie Universität Berlin, D-14195 Berlin, Germany.
J Plant Physiol. 2020 Oct;253:153252. doi: 10.1016/j.jplph.2020.153252. Epub 2020 Aug 13.
Periodic changes of light and dark regulate numerous processes in plants. Recently, a novel type of stress caused by an extended light period has been described in Arabidopsis thaliana and was named photoperiod stress. Although photoperiod stress causes the induction of numerous stress response genes of which many are indicators of oxidative stress, the exact timing and mechanisms involved in dealing with this stress have not yet been investigated. We describe the response of the cellular redox system in wild-type Arabidopsis, the photoperiod stress sensitive cytokinin receptor mutant ahk2 ahk3 and the clock mutant cca1 lhy. Photoperiod stress caused several changes in the ROS scavenging system including a reduction of the ascorbic acid (AsA) redox status and strong peroxide formation during the night following the extended photoperiod. The changes were associated with reduced catalase (CAT) and increased apoplastic peroxidase (PRX) activities. Consistently, the expression of the apoplastic PRX genes PRX4, PRX33, PRX34 and PRX71 was strongly induced by photoperiod stress. We show that extending the light period by only few hours causes a stress response during the following night suggesting that the photoperiod stress response might occur in a natural setting.
光暗周期的周期性变化调节着植物的众多过程。最近，在拟南芥中描述了一种新型的由长光周期引起的胁迫，称为光周期胁迫。尽管光周期胁迫会诱导许多应激反应基因的表达，其中许多是氧化应激的指标，但目前还没有研究涉及处理这种胁迫的确切时间和机制。我们描述了野生型拟南芥、光周期胁迫敏感的细胞分裂素受体突变体 ahk2 ahk3 和时钟突变体 cca1 lhy 的细胞氧化还原系统的反应。光周期胁迫导致 ROS 清除系统发生了几种变化，包括在长光周期后的夜间，抗坏血酸（AsA）氧化还原状态降低，过氧化氢大量形成。这些变化与过氧化氢酶（CAT）活性降低和胞外过氧化物酶（PRX）活性增加有关。一致地，胞外 PRX 基因 PRX4、PRX33、PRX34 和 PRX71 的表达被光周期胁迫强烈诱导。我们表明，仅延长几个小时的光照期就会在随后的夜间引起应激反应，这表明光周期应激反应可能在自然环境中发生。
