Protein S-nitrosylation, the covalent binding of nitric oxide (NO) to protein cysteine residues, is one of the main mechanisms of NO signaling in plant and animal cells. Using a combination of the biotin switch assay and label-free LC-MS/MS analysis, we revealed the S-nitroso-proteome of the woody model plant Populus x canescens. Under normal conditions, constitutively S-nitrosylated proteins in poplar leaves and calli comprise all aspects of primary and secondary metabolism. Acute ozone fumigation was applied to elicit ROS-mediated changes of the S-nitroso-proteome. This treatment changed the total nitrite and nitrosothiol contents of poplar leaves and affected the homeostasis of 32 S-nitrosylated proteins. Multivariate data analysis revealed that ozone exposure negatively affected the S-nitrosylation status of leaf proteins: 23 proteins were de-nitrosylated and 9 proteins had increased S-nitrosylation content compared to the control. Phenylalanine ammonia-lyase 2 (log2[ozone/control] = −3.6) and caffeic acid O-methyltransferase (−3.4), key enzymes catalyzing important steps in the phenylpropanoid and subsequent lignin biosynthetic pathways, respectively, were de-nitrosylated upon ozone stress. Measuring the in vivo and in vitro phenylalanine ammonia-lyase activity indicated that the increase of the phenylalanine ammonia-lyase activity in response to acute ozone is partly regulated by de-nitrosylation, which might favor a higher metabolic flux through the phenylpropanoid pathway within minutes after ozone exposure.
Research Unit Environmental Simulation, Institute for Biochemical Plant Pathology, Helmholtz Zentrum München, Neuherberg, Germany;Research Unit Environmental Simulation, Institute for Biochemical Plant Pathology, Helmholtz Zentrum München, Neuherberg, Germany;Research Unit Protein Science, Helmholtz Zentrum München, Neuherberg, Germany;Institute for Biochemical Plant Pathology, Helmholtz Zentrum München, Neuherberg, Germany;Institute for Biochemical Plant Pathology, Helmholtz Zentrum München, Neuherberg, Germany;Research Unit Protein Science, Helmholtz Zentrum München, Neuherberg, Germany;Institute for Biochemical Plant Pathology, Helmholtz Zentrum München, Neuherberg, Germany;Research Unit Environmental Simulation, Institute for Biochemical Plant Pathology, Helmholtz Zentrum München, Neuherberg, Germany
Recommended Citation:
Elisa Vanzo,Andrea Ghirardo,Juliane Merl-Pham,et al. S-Nitroso-Proteome in Poplar Leaves in Response to Acute Ozone Stress[J]. PLOS ONE,2014-01-01,9(9)