Grupo de Señalización Molecular y Sistemas Antioxidantes en Plantas, Unidad Asociada al CSIC (EEZ), Departamento de Bioquímica y Biología Molecular, Universidad de Jaén, Spain.
J Exp Bot. 2011 Mar;62(6):1803-13. doi: 10.1093/jxb/erq358. Epub 2010 Dec 20.
Nitric oxide (NO) and related molecules such as peroxynitrite, S-nitrosoglutathione (GSNO), and nitrotyrosine, among others, are involved in physiological processes as well in the mechanisms of response to stress conditions. In sunflower seedlings exposed to five different adverse environmental conditions (low temperature, mechanical wounding, high light intensity, continuous light, and continuous darkness), key components of the metabolism of reactive nitrogen species (RNS) and reactive oxygen species (ROS), including the enzyme activities L-arginine-dependent nitric oxide synthase (NOS), S-nitrosogluthathione reductase (GSNOR), nitrate reductase (NR), catalase, and superoxide dismutase, the content of lipid hydroperoxide, hydrogen peroxide, S-nitrosothiols (SNOs), the cellular level of NO, GSNO, and GSNOR, and protein tyrosine nitration [nitrotyrosine (NO(2)-Tyr)] were analysed. Among the stress conditions studied, mechanical wounding was the only one that caused a down-regulation of NOS and GSNOR activities, which in turn provoked an accumulation of SNOs. The analyses of the cellular content of NO, GSNO, GSNOR, and NO(2)-Tyr by confocal laser scanning microscopy confirmed these biochemical data. Therefore, it is proposed that mechanical wounding triggers the accumulation of SNOs, specifically GSNO, due to a down-regulation of GSNOR activity, while NO(2)-Tyr increases. Consequently a process of nitrosative stress is induced in sunflower seedlings and SNOs constitute a new wound signal in plants.
一氧化氮（NO）和相关分子，如过氧亚硝酸盐、S-亚硝基谷胱甘肽（GSNO）和硝基酪氨酸等，参与生理过程以及对应激条件的反应机制。在暴露于五种不同不利环境条件（低温、机械损伤、高光强、连续光照和连续黑暗）的向日葵幼苗中，活性氮物种（RNS）和活性氧物种（ROS）的代谢关键成分，包括酶活性依赖 L-精氨酸的一氧化氮合酶（NOS）、S-亚硝基谷胱甘肽还原酶（GSNOR）、硝酸还原酶（NR）、过氧化氢酶和超氧化物歧化酶、脂质氢过氧化物、过氧化氢、S-亚硝基硫醇（SNOs）、NO 的细胞水平、GSNO 和 GSNOR 的含量，以及蛋白质酪氨酸硝化[硝基酪氨酸（NO(2)-Tyr）]进行了分析。在所研究的应激条件中，机械损伤是唯一导致 NOS 和 GSNOR 活性下调的条件，这反过来又导致 SNOs 的积累。通过共焦激光扫描显微镜对 NO、GSNO、GSNOR 和 NO(2)-Tyr 的细胞含量进行分析，证实了这些生化数据。因此，提出机械损伤由于 GSNOR 活性下调而触发 SNOs（特别是 GSNO）的积累，而 NO(2)-Tyr 增加。因此，在向日葵幼苗中诱导了一种硝化应激过程，并且 SNOs 构成了植物中的新的伤口信号。
