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Nitric oxide induces the alternative oxidase pathway in Arabidopsis seedlings deprived of inorganic phosphate.

Royo B, Moran JF, Ratcliffe RG, Gupta KJ - J. Exp. Bot. (2015)

Bottom Line: The effects of the phosphate supply on growth, the production of NO, respiration, the AOX level and the production of superoxide were compared for wild-type (WT) seedlings and the nitrate reductase double mutant nia.Phosphate deprivation increased NO production in WT roots, and the AOX level and the capacity of the alternative pathway to consume electrons in WT seedlings; whereas the same treatment failed to stimulate NO production and AOX expression in the nia mutant, and the plants had an altered growth phenotype.It is concluded that NO is required for the induction of the AOX pathway when seedlings are grown under phosphate-limiting conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of Oxford, South Park Road, Oxford OX1 3RB, UK Institute of Agrobiotechnology, IdAB-CSIC-Public University of Navarre-Government of Navarre, Avda. Pamplona 123, E-31192, Mutilva, Navarre, Spain.

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Related in: MedlinePlus

Effect of Pi supply on the respiration rate of Arabidopsis seedlings. Oxygen consumption rates of 14-d-old seedlings were measured for: (A) WT seedlings grown on 1mM Pi; (B) nia seedlings grown on 1mM Pi; (C) WT seedlings grown on 0mM Pi; (D) nia seedlings grown on 0mM Pi; (E) nia seedlings grown on 0mM Pi plus 200 µM GSNO. The measurements were repeated after the addition of 1mM KCN, and again after adding 2mM SHAM. Means (n=6−9) with different letters are significantly different (one-way ANOVA, P<0.05) within a treatment.
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Figure 3: Effect of Pi supply on the respiration rate of Arabidopsis seedlings. Oxygen consumption rates of 14-d-old seedlings were measured for: (A) WT seedlings grown on 1mM Pi; (B) nia seedlings grown on 1mM Pi; (C) WT seedlings grown on 0mM Pi; (D) nia seedlings grown on 0mM Pi; (E) nia seedlings grown on 0mM Pi plus 200 µM GSNO. The measurements were repeated after the addition of 1mM KCN, and again after adding 2mM SHAM. Means (n=6−9) with different letters are significantly different (one-way ANOVA, P<0.05) within a treatment.

Mentions: The respiration rate of WT and nia seedlings was the same for plants grown with 1mM Pi (Fig. 3). In contrast there was a marked difference (P<0.05) between the lines grown on 0mM Pi, with the respiration rate of the nia mutant dropping to about 50% of the WT value (Fig. 3). The capacity of the AOX pathway was investigated by the sequential addition of KCN and SHAM. The addition of SHAM had a greater effect on the respiration rate of WT seedlings grown on 0mM Pi, reducing the KCN-independent respiration rate by 2.0 μmol O2 g FW-1 h-1 at 1mM Pi and by 2.9 μmol O2 g FW-1 h-1 at 0mM Pi (Fig. 3A, C); whereas the nia seedlings only showed an effect of SHAM on the seedlings were grown on 1mM Pi, reducing the respiration rate by 2.5 μmol O2 g FW-1 h-1 (Fig. 3B, D). The contrast between the WT and nia lines—specifically the absence of an effect of SHAM on the nia seedlings that were grown on 0mM Pi—suggests that there could be a positive correlation between NO production and AOX induction during Pi deprivation. Note that the residual respiration rates in the presence of both KCN and SHAM were generally high in these experiments, but they did not decrease when the inhibitor concentrations were increased to 2mM KCN and 5mM SHAM, indicating that the high values could not be attributed to poor penetration by the inhibitors (data not shown).


Nitric oxide induces the alternative oxidase pathway in Arabidopsis seedlings deprived of inorganic phosphate.

Royo B, Moran JF, Ratcliffe RG, Gupta KJ - J. Exp. Bot. (2015)

Effect of Pi supply on the respiration rate of Arabidopsis seedlings. Oxygen consumption rates of 14-d-old seedlings were measured for: (A) WT seedlings grown on 1mM Pi; (B) nia seedlings grown on 1mM Pi; (C) WT seedlings grown on 0mM Pi; (D) nia seedlings grown on 0mM Pi; (E) nia seedlings grown on 0mM Pi plus 200 µM GSNO. The measurements were repeated after the addition of 1mM KCN, and again after adding 2mM SHAM. Means (n=6−9) with different letters are significantly different (one-way ANOVA, P<0.05) within a treatment.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4588884&req=5

Figure 3: Effect of Pi supply on the respiration rate of Arabidopsis seedlings. Oxygen consumption rates of 14-d-old seedlings were measured for: (A) WT seedlings grown on 1mM Pi; (B) nia seedlings grown on 1mM Pi; (C) WT seedlings grown on 0mM Pi; (D) nia seedlings grown on 0mM Pi; (E) nia seedlings grown on 0mM Pi plus 200 µM GSNO. The measurements were repeated after the addition of 1mM KCN, and again after adding 2mM SHAM. Means (n=6−9) with different letters are significantly different (one-way ANOVA, P<0.05) within a treatment.
Mentions: The respiration rate of WT and nia seedlings was the same for plants grown with 1mM Pi (Fig. 3). In contrast there was a marked difference (P<0.05) between the lines grown on 0mM Pi, with the respiration rate of the nia mutant dropping to about 50% of the WT value (Fig. 3). The capacity of the AOX pathway was investigated by the sequential addition of KCN and SHAM. The addition of SHAM had a greater effect on the respiration rate of WT seedlings grown on 0mM Pi, reducing the KCN-independent respiration rate by 2.0 μmol O2 g FW-1 h-1 at 1mM Pi and by 2.9 μmol O2 g FW-1 h-1 at 0mM Pi (Fig. 3A, C); whereas the nia seedlings only showed an effect of SHAM on the seedlings were grown on 1mM Pi, reducing the respiration rate by 2.5 μmol O2 g FW-1 h-1 (Fig. 3B, D). The contrast between the WT and nia lines—specifically the absence of an effect of SHAM on the nia seedlings that were grown on 0mM Pi—suggests that there could be a positive correlation between NO production and AOX induction during Pi deprivation. Note that the residual respiration rates in the presence of both KCN and SHAM were generally high in these experiments, but they did not decrease when the inhibitor concentrations were increased to 2mM KCN and 5mM SHAM, indicating that the high values could not be attributed to poor penetration by the inhibitors (data not shown).

Bottom Line: The effects of the phosphate supply on growth, the production of NO, respiration, the AOX level and the production of superoxide were compared for wild-type (WT) seedlings and the nitrate reductase double mutant nia.Phosphate deprivation increased NO production in WT roots, and the AOX level and the capacity of the alternative pathway to consume electrons in WT seedlings; whereas the same treatment failed to stimulate NO production and AOX expression in the nia mutant, and the plants had an altered growth phenotype.It is concluded that NO is required for the induction of the AOX pathway when seedlings are grown under phosphate-limiting conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Sciences, University of Oxford, South Park Road, Oxford OX1 3RB, UK Institute of Agrobiotechnology, IdAB-CSIC-Public University of Navarre-Government of Navarre, Avda. Pamplona 123, E-31192, Mutilva, Navarre, Spain.

No MeSH data available.


Related in: MedlinePlus