scholarly journals Nitrogen Dioxide at Ambient Concentrations Induces Nitration and Degradation of PYR/PYL/RCAR Receptors to Stimulate Plant Growth: A Hypothetical Model

Plants ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 198 ◽  
Author(s):  
Misa Takahashi ◽  
Hiromichi Morikawa

Exposing Arabidopsis thaliana (Arabidopsis) seedlings fed with soil nitrogen to 10–50 ppb nitrogen dioxide (NO2) for several weeks stimulated the uptake of major elements, photosynthesis, and cellular metabolisms to more than double the biomass of shoot, total leaf area and contents of N, C P, K, S, Ca and Mg per shoot relative to non-exposed control seedlings. The 15N/14N ratio analysis by mass spectrometry revealed that N derived from NO2 (NO2-N) comprised < 5% of the total plant N, showing that the contribution of NO2-N as N source was minor. Moreover, histological analysis showed that leaf size and biomass were increased upon NO2 treatment, and that these increases were attributable to leaf age-dependent enhancement of cell proliferation and enlargement. Thus, NO2 may act as a plant growth signal rather than an N source. Exposure of Arabidopsis leaves to 40 ppm NO2 induced virtually exclusive nitration of PsbO and PsbP proteins (a high concentration of NO2 was used). The PMF analysis identified the ninth tyrosine residue of PsbO1 (9Tyr) as a nitration site. 9Tyr of PsbO1 was exclusively nitrated after incubation of the thylakoid membranes with a buffer containing NO2 and NO2− or a buffer containing NO2− alone. Nitration was catalyzed by illumination and repressed by photosystem II (PSII) electron transport inhibitors, and decreased oxygen evolution. Thus, protein tyrosine nitration altered (downregulated) the physiological function of cellular proteins of Arabidopsis leaves. This indicates that NO2-induced protein tyrosine nitration may stimulate plant growth. We hypothesized that atmospheric NO2 at ambient concentrations may induce tyrosine nitration of PYR/PYL/RCAR receptors in Arabidopsis leaves, followed by degradation of PYR/PYL/RCAR, upregulation of target of rapamycin (TOR) regulatory complexes, and stimulation of plant growth.

2001 ◽  
Vol 281 (6) ◽  
pp. H2289-H2294 ◽  
Author(s):  
Illarion V. Turko ◽  
Sisi Marcondes ◽  
Ferid Murad

High levels of reactive species of nitrogen and oxygen in diabetes may cause modifications of proteins. Recently, an increase in protein tyrosine nitration was found in several diabetic tissues. To understand whether protein tyrosine nitration is the cause or the result of the associated diabetic complications, it is essential to identify specific proteins vulnerable to nitration with in vivo models of diabetes. In the present study, we have demonstrated that succinyl-CoA:3-oxoacid CoA-transferase (SCOT; EC 2.8.3.5 ) is susceptible to tyrosine nitration in hearts from streptozotocin-treated rats. After 4 and 8 wk of streptozotocin administration and diabetes progression, SCOT from rat hearts had a 24% and 39% decrease in catalytic activity, respectively. The decrease in SCOT catalytic activity is accompanied by an accumulation of nitrotyrosine in SCOT protein. SCOT is a mitochondrial matrix protein responsible for ketone body utilization. Ketone bodies provide an alternative source of energy during periods of glucose deficiency. Because diabetes results in profound derangements in myocardial substrate utilization, we suggest that SCOT tyrosine nitration is a contributing factor to this impairment in the diabetic heart.


2018 ◽  
Vol 118 (3) ◽  
pp. 1338-1408 ◽  
Author(s):  
Gerardo Ferrer-Sueta ◽  
Nicolás Campolo ◽  
Madia Trujillo ◽  
Silvina Bartesaghi ◽  
Sebastián Carballal ◽  
...  

2002 ◽  
Vol 16 (9) ◽  
pp. 1144-1144 ◽  
Author(s):  
William M. Deen ◽  
Steven R. Tannenbaum ◽  
Joseph S. Beckman

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