Nitric oxide is essential for cadmium‐induced peroxule formation and peroxisome proliferation

• Published in: Plant, cell and environment cell and environment, 2020-10, Vol.43 (10), p.2492-2507
• Main Authors: Terrón‐Camero, Laura C., Rodríguez‐Serrano, María, Sandalio, Luisa M., Romero‐Puertas, María C.
• Format: Article
• Language: English
• Subjects: Arabidopsis - metabolism; Arabidopsis - physiology; Arabidopsis - ultrastructure; Blotting, Western; Cadmium; Cadmium - metabolism; carbonylation; Catalase; Confocal microscopy; Electron microscopy; Gene Expression Regulation, Plant; Hydrogen Peroxide - metabolism; Metabolism; Microscopy; Microscopy, Confocal; Mutants; Nitric oxide; Nitric Oxide - metabolism; Nitric Oxide - physiology; Oxidative metabolism; Peroxisomes; Peroxisomes - metabolism; Peroxisomes - ultrastructure; peroxules; Phenotypes; Plant Leaves - metabolism; Plant Leaves - ultrastructure; Proteins; Real-Time Polymerase Chain Reaction; Signaling; signalling; Stress; S‐nitrosylation
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/pce.13855

Nitric oxide (NO) and nitrosylated derivatives are produced in peroxisomes, but the impact of NO metabolism on organelle functions remains largely uncharacterised. Double and triple NO‐related mutants expressing cyan florescent protein (CFP)‐SKL (nox1 × px‐ck and nia1 nia2 × px‐ck) were generated to determine whether NO regulates peroxisomal dynamics in response to cadmium (Cd) stress using confocal microscopy. Peroxule production was compromised in the nia1 nia2 mutants, which had lower NO levels than the wild‐type plants. These findings show that NO is produced early in the response to Cd stress and was involved in peroxule production. Cd‐induced peroxisomal proliferation was analysed using electron microscopy and by the accumulation of the peroxisomal marker PEX14. Peroxisomal proliferation was inhibited in the nia1 nia2 mutants. However, the phenotype was recovered by exogenous NO treatment. The number of peroxisomes and oxidative metabolism were changed in the NO‐related mutant cells. Furthermore, the pattern of oxidative modification and S‐nitrosylation of the catalase (CAT) protein was changed in the NO‐related mutants in both the absence and presence of Cd stress. Peroxisome‐dependent signalling was also affected in the NO‐related mutants. Taken together, these results show that NO metabolism plays an important role in peroxisome functions and signalling. A tight regulation of NO is required for optimal peroxisomal function and dependent signalling. NO is essential for peroxule production and peroxisome proliferation occurring in plant response to Cd. Additionally, peroxisome number and distribution as well as the oxidative metabolism of the organelle are altered by different levels of NO under control and stress conditions.