1-3-dihydroxy-4-4-5-5-tetramethyl-2-(4-carboxyphenyl)tetrahydroimidazole and ethylene

In response to flooding/waterlogging, plants develop various anatomical changes including the formation of lysigenous aerenchyma for the delivery of oxygen to roots. Under hypoxia, plants produce high levels of nitric oxide (NO) but the role of this molecule in plant-adaptive response to hypoxia is not known. Here, we investigated whether ethylene-induced aerenchyma requires hypoxia-induced NO. Under hypoxic conditions, wheat roots produced NO apparently via nitrate reductase and scavenging of NO led to a marked reduction in aerenchyma formation. Interestingly, we found that hypoxically induced NO is important for induction of the ethylene biosynthetic genes encoding ACC synthase and ACC oxidase. Hypoxia-induced NO accelerated production of reactive oxygen species, lipid peroxidation, and protein tyrosine nitration. Other events related to cell death such as increased conductivity, increased cellulase activity, DNA fragmentation, and cytoplasmic streaming occurred under hypoxia, and opposing effects were observed by scavenging NO. The NO scavenger cPTIO (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt) and ethylene biosynthetic inhibitor CoCl

Topics: Benzoates; Cobalt; Ethylenes; Imidazoles; Nitrate Reductase; Nitric Oxide; Nitrites; Oxygen; Plant Growth Regulators; Plant Proteins; Plant Roots; Reactive Oxygen Species; Signal Transduction; Stress, Physiological; Triticum

To better understand nitric oxide (NO) responsive proteins, we investigated the proteomic differences between untreated (control), sodium nitroprusside (SNP) treated, and carboxy-PTIO potassium salt (cPTIO, NO scavenger) followed by SNP treated cotton plants. This is the first study to examine the effect of different concentrations of NO on the leaf proteome in cotton using a label-free approach based on nanoscale ultraperformance liquid chromatography-electrospray ionization (ESI)-low/high-collision energy MS analysis (MS(E)). One-hundred and sixty-six differentially expressed proteins were identified. Forty-seven of these proteins were upregulated, 82 were downregulated, and 37 were expressed specifically under different conditions. The 166 proteins were functionally divided into 17 groups and localized to chloroplast, Golgi apparatus, cytoplasm, and so forth. The pathway analysis demonstrated that NO is involved in various physiological activities and has a distinct influence on carbon fixation in photosynthetic organisms and photosynthesis. In addition, this is the first time proteins involved in ethylene synthesis were identified to be regulated by NO. The characterization of these protein networks provides a better understanding of the possible regulation mechanisms of cellular activities occurring in the NO-treated cotton leaves and offers new insights into NO responses in plants.

Topics: Benzoates; Chlorophyll; Chloroplasts; Cytoplasm; Databases, Protein; Ethylenes; Gene Expression Regulation, Plant; Golgi Apparatus; Gossypium; Imidazoles; Nitric Oxide; Nitroprusside; Photosynthesis; Plant Leaves; Plant Proteins; Protein Biosynthesis; Proteome; Proteomics; Seeds; Spectrometry, Mass, Electrospray Ionization