Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, CSIC, C/Profesor Albareda 1, E-18008 Granada, Spain.
Group of Biochemistry and Cell Signaling in Nitric Oxide, Department of Biochemistry and Molecular Biology, University of Jaén, Campus "Las Lagunillas", E-23071 Jaén, Spain.
Nitric Oxide. 2017 Aug 1;68:103-110. doi: 10.1016/j.niox.2016.12.010. Epub 2016 Dec 28.
Lead (Pb) contamination has a toxic effect on plant metabolisms, leading to a decrease in biomass production. The free radical nitric oxide (NO) is involved in the mechanism of response to a wide range of abiotic stresses. However, little is known about the interplay between Pb-induced stress and NO metabolism. Peroxisomes are sub-cellular compartments involved in multiple cellular metabolic pathways which are characterized by an active nitro-oxidative metabolism. Thus, Arabidopsis thaliana mutants expressing cyan fluorescent protein (CFP) through the addition of peroxisomal targeting signal 1 (PTS1), which enables peroxisomes to be visualized in vivo by confocal laser scanning microscopy (CLSM) combined with fluorescent probes for nitric oxide (NO), superoxide anion (O) and peroxynitrite (ONOO), were used to evaluate the potential involvement of these organelles in the mechanism of response to 150 μM lead-induced stress. Both NO and O radicals, and consequently ONOO, were overproduced under Pb-stress. Additionally, biochemical and gene expression analyses of peroxisomal enzymes, including the antioxidant catalase (CAT) and two photorespiration enzymes, such as glycolate oxidase (GOX) and hydroxypyruvate reductase (HPR), show that, under Pb-stress, only the catalase was negatively affected, while the two photorespiration enzymes remained unaffected. These results corroborate the involvement of plant peroxisomal metabolisms in the mechanism of response to lead contamination and highlight the importance of the peroxisomal NO metabolism.
铅（Pb）污染对植物代谢有有毒影响，导致生物量生产减少。自由基一氧化氮（NO）参与对广泛的非生物胁迫的响应机制。然而，对于 Pb 诱导的应激和 NO 代谢之间的相互作用知之甚少。过氧化物酶体是参与多种细胞代谢途径的亚细胞区室，其特征是活性硝基-氧化代谢。因此，通过添加过氧化物酶体靶向信号 1（PTS1）表达青色荧光蛋白（CFP）的拟南芥突变体，能够通过共焦激光扫描显微镜（CLSM）与用于一氧化氮（NO）、超氧阴离子（O）和过氧亚硝酸盐（ONOO）的荧光探针在体内可视化这些细胞器，用于评估这些细胞器在对 150 μM 铅诱导的应激的响应机制中的潜在参与。在 Pb 胁迫下，NO 和 O 自由基，以及随后的 ONOO，均过量产生。此外，过氧化物酶体酶的生化和基因表达分析，包括抗氧化酶过氧化氢酶（CAT）和两种光呼吸酶，如乙醇酸氧化酶（GOX）和羟基丙酮酸还原酶（HPR），表明在 Pb 胁迫下，只有过氧化氢酶受到负面影响，而两种光呼吸酶不受影响。这些结果证实了植物过氧化物酶体代谢在应对铅污染的响应机制中的参与，并强调了过氧化物酶体 NO 代谢的重要性。
